CN116057076A - Acrylic rubber bag excellent in roll processability, banbury processability, water resistance, strength characteristics and compression set resistance - Google Patents

Acrylic rubber bag excellent in roll processability, banbury processability, water resistance, strength characteristics and compression set resistance Download PDF

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CN116057076A
CN116057076A CN202180058024.0A CN202180058024A CN116057076A CN 116057076 A CN116057076 A CN 116057076A CN 202180058024 A CN202180058024 A CN 202180058024A CN 116057076 A CN116057076 A CN 116057076A
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acrylic rubber
rubber bag
weight
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rubber
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增田浩文
川中孝文
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Zeon Corp
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    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F220/00—Copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical or a salt, anhydride ester, amide, imide or nitrile thereof
    • C08F220/02—Monocarboxylic acids having less than ten carbon atoms; Derivatives thereof
    • C08F220/10—Esters
    • C08F220/12—Esters of monohydric alcohols or phenols
    • C08F220/16—Esters of monohydric alcohols or phenols of phenols or of alcohols containing two or more carbon atoms
    • C08F220/18—Esters of monohydric alcohols or phenols of phenols or of alcohols containing two or more carbon atoms with acrylic or methacrylic acids
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F2/00—Processes of polymerisation
    • C08F2/12—Polymerisation in non-solvents
    • C08F2/16—Aqueous medium
    • C08F2/22—Emulsion polymerisation
    • C08F2/24—Emulsion polymerisation with the aid of emulsifying agents
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F2/00—Processes of polymerisation
    • C08F2/38—Polymerisation using regulators, e.g. chain terminating agents, e.g. telomerisation
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F22/00—Homopolymers and copolymers of compounds having one or more unsaturated aliphatic radicals each having only one carbon-to-carbon double bond, and at least one being terminated by a carboxyl radical and containing at least one other carboxyl radical in the molecule; Salts, anhydrides, esters, amides, imides or nitriles thereof
    • C08F22/10—Esters
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F220/00—Copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical or a salt, anhydride ester, amide, imide or nitrile thereof
    • C08F220/02—Monocarboxylic acids having less than ten carbon atoms; Derivatives thereof
    • C08F220/10—Esters
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F220/00—Copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical or a salt, anhydride ester, amide, imide or nitrile thereof
    • C08F220/02—Monocarboxylic acids having less than ten carbon atoms; Derivatives thereof
    • C08F220/10—Esters
    • C08F220/26—Esters containing oxygen in addition to the carboxy oxygen
    • C08F220/28—Esters containing oxygen in addition to the carboxy oxygen containing no aromatic rings in the alcohol moiety
    • C08F220/281—Esters containing oxygen in addition to the carboxy oxygen containing no aromatic rings in the alcohol moiety and containing only one oxygen, e.g. furfuryl (meth)acrylate or 2-methoxyethyl (meth)acrylate
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F6/00—Post-polymerisation treatments
    • C08F6/14—Treatment of polymer emulsions
    • C08F6/22—Coagulation
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
    • C08K3/00—Use of inorganic substances as compounding ingredients
    • C08K3/01—Use of inorganic substances as compounding ingredients characterized by their specific function
    • C08K3/013—Fillers, pigments or reinforcing additives
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L33/00—Compositions of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical, or of salts, anhydrides, esters, amides, imides or nitriles thereof; Compositions of derivatives of such polymers
    • C08L33/04—Homopolymers or copolymers of esters

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  • Addition Polymer Or Copolymer, Post-Treatments, Or Chemical Modifications (AREA)
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Abstract

The invention provides an acrylic rubber bag with excellent roller processability, banbury processability, water resistance, strength characteristics and compression set resistance. The acrylic rubber bag of the present invention is composed of an acrylic rubber having at least one reactive group selected from a carboxyl group, an epoxy group and a chlorine atom, wherein the weight average molecular weight (Mw) in the absolute molecular weight and the absolute molecular weight distribution measured by GPC-MALS method is 1000000 ～ 3500000, the ratio (Mw/Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) is 3.7 to 6.5, the amount of methyl ethyl ketone insoluble component in the acrylic rubber bag is 50 wt% or less, the amount of ash is 0.2 wt% or less, and the total amount of sodium, magnesium, calcium, phosphorus and sulfur in the ash is 50 wt% or more.

Description

Acrylic rubber bag excellent in roll processability, banbury processability, water resistance, strength characteristics and compression set resistance
Technical Field
The present invention relates to an acrylic rubber bag, a method for producing the same, a rubber composition, and a crosslinked rubber, and more particularly, to an acrylic rubber bag excellent in roll processability and banbury processability, and excellent in water resistance, strength characteristics, and compression set resistance of the crosslinked rubber, a method for producing the same, a rubber composition containing the same, and a crosslinked rubber obtained by crosslinking the same.
Background
Acrylic rubber is a polymer containing an acrylic ester as a main component, and is generally known as a rubber excellent in heat resistance, oil resistance and ozone resistance, and is widely used in fields related to automobiles, and the like.
For example, in patent document 1 (international publication No. 2019/188709), the following method is disclosed: adding monomer components composed of ethyl acrylate, butyl acrylate, methoxyethyl acrylate and monobutyl fumarate, water and sodium lauryl sulfate, repeatedly degassing under reduced pressure and replacing with nitrogen, adding sodium formaldehyde sulfoxylate and cumene hydroperoxide as an organic radical generator, initiating emulsion polymerization at normal pressure and normal temperature, performing emulsion polymerization until the polymerization conversion reaches 95 wt%, solidifying with calcium chloride aqueous solution, filtering with a metal mesh, and dehydrating and drying with an extrusion dryer with a screw to prepare the acrylic rubber. However, the acrylic rubber obtained by the present method has problems of extremely poor roll processability and banbury processability, and also poor storage stability and water resistance.
Patent document 2 (japanese patent application laid-open No. 2019-119772) discloses the following method: after a monomer emulsion was prepared from a monomer component comprising ethyl acrylate, butyl acrylate, methoxyethyl acrylate and monobutyl maleate using pure water and sodium lauryl sulfate and polyoxyethylene lauryl ether as emulsifiers, a part of the monomer emulsion was put into a polymerization reaction tank and cooled to 12℃under a nitrogen stream, then the remaining part of the monomer emulsion, ferrous sulfate, sodium ascorbate and an aqueous potassium persulfate solution as an inorganic radical generator were continuously added dropwise over 3 hours, then the emulsion polymerization was continued at 23℃for 1 hour until the polymerization conversion reached 97% by weight, then sodium sulfate was continuously added, whereby an aqueous pellet was obtained by coagulation filtration, and after the aqueous pellet was washed with water 4 times, washed with acid 1 time and washed with pure water 1 time, an acrylic rubber was continuously prepared into a sheet shape with an extrusion dryer having a screw, and crosslinked with an aliphatic polyamine compound such as hexamethylenediamine carbamate. However, the sheet-like acrylic rubber obtained by the present method has problems of poor roll processability and poor water resistance of the crosslinked product. In addition, patent document 2 does not describe the encapsulation of the sheet-like acrylic rubber obtained.
Patent document 3 (japanese patent application laid-open No. 1-135811) discloses the following method: a monomer composition comprising ethyl acrylate, caprolactone-added acrylate, cyanoethyl acrylate and vinyl chloride is prepared by emulsifying 1/4 of a monomer mixture comprising the above monomer composition and n-dodecyl mercaptan as a chain transfer agent with sodium lauryl sulfate, polyethylene glycol nonylphenol ether and distilled water, adding sodium sulfite and ammonium persulfate as an inorganic radical generator to initiate polymerization, dropwise adding the rest of the monomer mixture and 2% ammonium persulfate aqueous solution while maintaining the temperature at 60 ℃, continuing to polymerize for 2 hours after dropwise adding, adding a latex with a polymerization conversion rate of 96-99% into 80 ℃ sodium chloride aqueous solution to solidify, sufficiently washing with water, and drying to prepare acrylic rubber, and crosslinking with sulfur. However, the acrylic rubber obtained by the present method has problems of poor roll processability and storage stability, and poor strength characteristics and water resistance of the crosslinked product.
Patent document 4 (japanese patent application laid-open No. 2018-168343) discloses the following method: a monomer emulsion comprising the above monomer components, pure water, sodium lauryl sulfate, polyethylene glycol monostearate and n-dodecyl mercaptan as a chain transfer agent was prepared from ethyl acrylate, butyl acrylate and monobutyl fumarate, and then a part of the monomer emulsion and pure water were charged into a polymerization tank and cooled to 12℃to continuously add dropwise the remaining part of the monomer emulsion, ferrous sulfate, sodium ascorbate and potassium persulfate as an inorganic radical generator over 2.5 hours, and then, after continuing the reaction at 23℃for 1 hour, industrial water was added and heated to 85℃to continuously add sodium sulfate at 85℃to thereby solidify to obtain an aqueous pellet, and after washing with pure water 3 times, an acrylic rubber was produced by drying with a hot air dryer and crosslinked with 2, 2-bis [4- (4-aminophenoxy) phenyl ] propane. However, the acrylic rubber obtained by the method is excellent in stress relaxation property and extrusion processability, but has problems of insufficient roll processability and storage stability, and poor strength characteristics and water resistance of a crosslinked product.
Patent document 5 (japanese patent application laid-open No. 9-143229) discloses the following method: a monomer mixture comprising ethyl acrylate, a specific acrylic ester and vinyl monochloride, sodium lauryl sulfate as an emulsifier, n-octanethiol as a chain transfer agent and water are added into a reaction vessel, nitrogen substitution is performed, then ammonium bisulfide and sodium persulfate as an inorganic radical generator are added to initiate polymerization, copolymerization is performed at 55 ℃ for 3 hours at a reaction conversion rate of 93-96%, and an acrylic rubber is produced and crosslinked with sulfur. However, the acrylic rubber obtained by the method has problems of poor storage stability and roll processability, and poor strength characteristics and water resistance of the crosslinked product.
Patent document 6 (japanese patent application laid-open No. 62-64809) discloses an acrylic rubber which is excellent in processability, compression set and tensile strength and can be vulcanized with sulfur, and is characterized in that: from 50 to 99.9% by weight of at least one compound of alkyl acrylate and alkoxyalkyl acrylate, from 0.1 to 20% by weight of a dihydro-dicyclopentenyl-containing ester of an unsaturated carboxylic acid having a radical-reactive group, from 0% to over 20% by weight of a copolymer comprising at least one monomer selected from the group consisting of other monovinyl compounds, mono1, 1-vinylidene (vinyl) compounds and mono1, 2-vinylidene (vinyl) compounds, wherein the polystyrene-converted number average molecular weight (Mn) of tetrahydrofuran as an eluent is 20 to 120 tens of thousands, and the ratio (Mw/Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) is 10 or less. Furthermore, it is described that: the number average molecular weight (Mn) is 20 to 100 tens of thousands, preferably 20 to 100 tens of thousands, and if Mn is less than 20 tens of thousands, the physical properties and processability of the sulfide are poor, and if it is more than 120 tens of thousands, the processability is poor, and when it is more than 10, the compression set becomes large with respect to the ratio (Mw/Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn), which is not preferable. As specific examples thereof, the following manufacturing methods are disclosed: a process for producing a calcium chloride aqueous solution, which comprises polymerizing an acrylic rubber containing a monomer component such as ethyl acrylate, a radical crosslinkable dicyclopentenyl acrylate, sodium lauryl sulfate as an emulsifier, potassium persulfate as an inorganic radical generator, octyl mercaptoacetate as a molecular weight regulator, and t-dodecyl mercaptan as variables, and having a number average molecular weight (Mn) of 53 to 115 ten thousand, a weight average molecular weight (Mw) of 354 to 626 ten thousand, and a ratio (Mw/Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) of 4.7 to 8, followed by sufficient water washing and direct drying. Further, it is shown in examples and comparative examples that when the amount of the chain transfer agent is small, the number average molecular weight (Mw) of the obtained acrylic rubber increases to 500 ten thousand, the ratio (Mw/Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) becomes narrow to 1.4, and when the amount of the chain transfer agent is large, the number average molecular weight (Mn) decreases to 20 ten thousand, and the ratio (Mw/Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) becomes extremely wide to 17. However, the acrylic rubber obtained by the present method has poor compression set resistance and storage stability, and therefore has problems that even if an appropriate molecular weight distribution (Mw/Mn) is obtained in a polymerization reaction using a radical generator, the molecular weight (Mw, mn) becomes excessively large and complicated, and the roll processability and banbury processability are insufficient. In addition, the acrylic rubber obtained by the present method has the following problems: in cross-linking In the reaction, sulfur as a crosslinking agent and a vulcanization accelerator were added and kneaded by a roll, and then 100kg/cm was carried out at 170 DEG C 2 The vulcanization press of (3) for 15 minutes and crosslinking at 175℃for 4 hours in a Gill oven require a long time, and the resulting crosslinked product has problems such as poor compression set resistance, water resistance and strength characteristics, and poor physical property change after thermal deterioration.
On the other hand, regarding the rubber-encapsulated acrylic rubber, for example, patent document 7 (japanese patent application laid-open No. 2006-328239) discloses a method for producing a rubber polymer, which comprises the steps of: a step of contacting a polymer latex with a coagulating liquid to obtain a pellet slurry containing a pellet-like rubber polymer; using stirring power of 1kW/m 3 The above-mentioned stirrer having a stirring/crushing function crushes the crumb rubber polymer contained in the crumb slurry; a dehydration step of removing water from the crushed crumb slurry of the crumb rubber polymer to obtain a crumb rubber polymer; the step of heat-drying the crumb rubber polymer from which the water has been removed, and the step of introducing the dried crumb into a baler in the form of a sheet and compacting the same to form a bale are also described. The rubber polymer used herein specifically shows an unsaturated nitrile-conjugated diene copolymer latex obtained by emulsion polymerization, and also shows a copolymer composed only of an acrylic ester, such as ethyl acrylate/n-butyl acrylate copolymer, ethyl acrylate/n-butyl acrylate/2-methoxyethyl acrylate copolymer, and the like. However, an acrylic rubber composed only of an acrylic ester has a problem of poor properties of crosslinked rubber such as heat resistance and compression set resistance.
As a gellable acrylic rubber having an ion-reactive group excellent in heat resistance and compression set resistance, for example, patent document 8 (handbook of international publication No. 2018/116828) discloses the following method: the monomer components comprising ethyl acrylate, n-butyl acrylate and mono-n-butyl fumarate were emulsified with sodium lauryl sulfate, polyethylene glycol monostearate and water as emulsifiers, cumene hydroperoxide as an organic radical generator was added to the emulsion polymerization reaction mixture until the polymerization conversion became 95%, the resulting acrylic rubber latex was added to an aqueous solution of magnesium sulfate and dimethylamine-ammonia-epichlorohydrin polycondensate as a polymeric flocculant, followed by stirring at 85℃to give a pellet slurry, and the whole amount of the pellet slurry was passed through a 100-mesh metal mesh after washing with water 1 time, and only the solid component was collected to recover the pellet-like acrylic rubber. Also described is: according to this method, the pellets in the aqueous state obtained are dehydrated by centrifugal separation or the like, dried at 50 to 120 ℃ by a belt dryer or the like, and introduced into a baler to be compressed and baled. However, there are the following problems in this method: the problem that a large amount of water-containing aggregates in a semi-coagulated state are generated during the coagulation reaction and adhere to the coagulation tank, and the problems such as a coagulant and an emulsifier cannot be sufficiently removed by washing, and the problems such as poor roll processability, banbury processability and water resistance of the acrylic rubber itself, insufficient removal of air even when a rubber bag is produced, and poor storage stability are also caused.
Further, regarding the amount of a specific solvent insoluble component of an acrylic rubber, for example, patent document 9 (japanese patent No. 3599962) discloses an acrylic rubber composition excellent in extrusion processability such as extrusion speed, die swell, surface properties, etc., which comprises an acrylic rubber obtained by copolymerizing 95 to 99.9% by weight of an alkyl acrylate or an alkoxyalkyl acrylate with 0.1 to 5% by weight of a polymerizable monomer having 2 or more radically reactive unsaturated groups having different reactivities in the presence of a radical polymerization initiator, a reinforcing filler, and an organic peroxide-based vulcanizing agent, to obtain an acrylic rubber having a gel percentage of 5% by weight or less of an acetone insoluble component. The acrylic rubber having a very small gel percentage (60%) as compared with the acrylic rubber having a high gel percentage (60%) as obtained in the usual acidic region (pH 4 before polymerization, pH3.4 after polymerization) is obtained by adjusting the pH of the polymerization liquid to 6 to 8 with sodium hydrogencarbonate or the like. Specifically, water, sodium lauryl sulfate, polyoxyethylene nonylphenyl ether, sodium carbonate, and boric acid as an emulsifier were added and adjusted to 75 ℃, and then tert-butyl hydroperoxide, ronomide, disodium ethylenediamine tetraacetate, and ferrous sulfate (pH 7.1 in this case) as an organic radical generator were added, followed by emulsion polymerization by dropping monomer components of ethyl acrylate and allyl methacrylate, and the resulting emulsion (pH 7) was salted out with an aqueous sodium sulfate solution, washed with water, and dried to obtain an acrylic rubber. However, the acrylic rubber containing (meth) acrylic acid ester as a main component is decomposed in a neutral to alkaline region, and even if the processability is improved, there are problems of poor storage stability and strength characteristics, and further, problems of poor roll processability, banbury processability, crosslinkability, water resistance and compression set resistance.
Further, in patent document 10 (international publication No. 2018/143101 manual), the following technique is disclosed: an acrylic rubber obtained by emulsion polymerizing a (meth) acrylic acid ester and an ion-crosslinkable monomer, wherein the ratio of the complex viscosity at 100 ℃ ([ eta ]100 ℃) to the complex viscosity at 60 ℃ ([ eta ]60 ℃) to the complex viscosity at 100 ℃ ([ eta ]100 ℃) is 0.8 or less, and the extrusion moldability, particularly the discharge amount, the discharge length and the surface properties of a rubber composition comprising a reinforcing agent and a crosslinking agent are improved. The gel content of the acrylic rubber used in this technique, which is a THF (tetrahydrofuran) insoluble component, is described as 80% by weight or less, preferably 5 to 80% by weight, and preferably as much as possible in the range of 70% or less, and when the gel content is less than 5%, the extrudability is deteriorated. Further, it is described that the weight average molecular weight (Mw) of the acrylic rubber used is 200000 ～ 1000000, and when the weight average molecular weight (Mw) exceeds 1000000, the viscoelasticity of the acrylic rubber becomes too high, which is not preferable. However, no method has been described for improving the workability of rolls, the workability of banbury and the like, and the water resistance.
Prior art literature
Patent literature
Patent document 1: international publication No. 2019/188709;
patent document 2: japanese patent application laid-open No. 2019-119772;
patent document 3: japanese patent laid-open No. 1-135811;
patent document 4: japanese patent application laid-open No. 2018-168343;
patent document 5: japanese patent laid-open No. 9-143229;
patent document 6: japanese patent laid-open No. 62-64809;
patent document 7: japanese patent laid-open No. 2006-328239;
patent document 8: international publication No. 2018/116828 handbook;
patent document 9: japanese patent No. 3599962;
patent document 10: international publication No. 2018/143101.
Disclosure of Invention
Problems to be solved by the invention
The present invention has been made in view of the actual circumstances of the prior art, and an object thereof is to provide an acrylic rubber bag excellent in roll processability and banbury processability and having a high balance among water resistance, strength characteristics and compression set resistance of a crosslinked product, a method for producing the same, a rubber composition comprising the acrylic rubber bag, and a crosslinked rubber product obtained by crosslinking the same.
Solution for solving the problem
The present inventors have conducted intensive studies in view of the above problems, and as a result, have found that an acrylic rubber bag is composed of an acrylic rubber having a specific reactive group and having a weight average molecular weight (Mw) and a ratio of a weight average molecular weight (Mn) to a number average molecular weight (Mw/Mn) of an absolute molecular weight and an absolute molecular weight distribution measured by a GPC-MALS method in a specific range, and that by limiting a specific solvent-insoluble component amount and a specific ash amount, roll processability and banbury processability are excellent, and that a crosslinked product is highly excellent in water resistance, strength characteristics and compression set resistance.
The present inventors have found that an acrylic rubber bag comprising an acrylic rubber having an ion-reactive group capable of reacting with a crosslinking agent such as a carboxyl group, an epoxy group, or a chlorine atom and having an absolute molecular weight as measured by the GPC-MALS method and a specific weight on the high molecular weight side has excellent short-time crosslinkability, strength characteristics, and compression set resistance.
The present inventors have found that, in GPC measurement, the reactive group-containing acrylic rubber is not sufficiently dissolved in tetrahydrofuran used in GPC measurement of the conventional radical-reactive acrylic rubber obtained by copolymerizing ethyl acrylate, dicyclopentenyl acrylate, or the like, and each molecular weight and molecular weight distribution cannot be clearly and reproducibly measured, but by using a specific solvent having an SP value higher than that of tetrahydrofuran as an eluent, it is possible to completely dissolve and reproducibly measure the reactive group-containing acrylic rubber, and by setting each characteristic value to a specific value, roll workability, banbury workability, and water resistance, strength characteristics, and compression set resistance of a crosslinked product of an acrylic rubber bag can be highly balanced.
Regarding the roll processability, the present inventors have found that, in particular, the weight average molecular weight (Mw) of the absolute molecular weight of the acrylic rubber constituting the acrylic rubber bag measured by GPC-MALS method is within a specific range, and it is important to expand the ratio (Mw/Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) of the absolute molecular weight distribution, so that the roll processability of the acrylic rubber bag and the strength characteristics of the crosslinked product can be highly balanced. The present inventors have found that it is not easy to expand the ratio (Mw/Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) of the absolute molecular weight distribution of the constituent acrylic rubber measured by GPC-MALS method to a specific range, but it is possible to achieve this by adding the chain transfer agent in the polymerization reaction after it is batchwise or by drying the aqueous pellet in a screw type biaxial extrusion dryer in a high shear manner. Further, it is found that when the ratio (Mw/Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) is excessively increased, the low molecular weight component becomes excessive, and the strength characteristics are lowered.
Regarding the banbury workability, the present inventors found that the smaller the amount of methyl ethyl ketone insoluble component of the acrylic rubber bag, the more excellent. The present inventors found that the amount of the methyl ethyl ketone insoluble component of the acrylic rubber bag is generated during the polymerization reaction, and particularly, when the polymerization conversion rate is increased in order to improve the strength characteristics, it is extremely difficult to control, but the chain transfer agent is present in the latter half of the polymerization step, so that it is possible to suppress the amount to some extent, and the extremely increased methyl ethyl ketone insoluble component is obtained by melt-kneading and drying the acrylic rubber in a state substantially free of moisture (the moisture content is less than 1% by weight) in a screw type biaxial extrusion dryer, so that the extremely increased methyl ethyl ketone insoluble component disappears without deviation, and the roll processability of the acrylic rubber bag can be remarkably improved. Further, the present inventors have found that the banbury processability and the strength characteristics of an acrylic rubber bag produced by melt-extruding in a state in which water is substantially removed by using a screw type biaxial extrusion dryer are highly balanced.
Regarding the water resistance, the present inventors found that the amount of ash in the acrylic rubber bag is small and that it is particularly excellent when ash is a specific component. The present inventors have found that although it is quite difficult to reduce the ash content in the acrylic rubber, the washing efficiency in hot water and the ash removal efficiency in dehydration of the aqueous pellets subjected to the coagulation reaction by the specific method are high, and the ash of the specific component is difficult to remove in washing, but by performing the same method, the ash of the specific component can be easily reduced and the water resistance can be remarkably improved. The present inventors have found that, in particular, by increasing the ratio of the specific particle size of the aqueous aggregates produced in the coagulation step and washing, dehydrating and drying the aqueous aggregates, the water resistance can be significantly improved without impairing the properties such as the roll processability, the banbury processability, the strength properties and the compression set resistance of the obtained acrylic rubber bag. Further, the present inventors have found that when a specific emulsifier is used in emulsion polymerization of acrylic rubber or a specific coagulant is used in the case of coagulating an emulsion polymerization liquid, the acrylic rubber bag is excellent in water resistance and is remarkably improved in releasability from a metal mold or the like.
The present inventors have found that by increasing the specific gravity of an acrylic rubber bag, roll processability, banbury processability, water resistance, strength characteristics and compression set resistance are excellent, and storage stability can be greatly improved. The present inventors have found that the acrylic rubber of the present invention having a specific reactive group has tackiness and is difficult to remove air, and a large amount of air is involved in the pellet-like acrylic rubber obtained by directly drying the aqueous pellets (the specific gravity becomes small), and the storage stability is deteriorated, but by compacting the pellet-like acrylic rubber with a packer or the like to carry out the rubber encapsulation, some of the air can be removed slightly and the storage stability can be improved; and extrusion-drying the aqueous pellets under reduced pressure by a screw-type biaxial extrusion dryer and extruding and laminating in an air-free sheet form, whereby an acrylic rubber bag containing little air, having a high specific gravity and significantly improved storage stability can be produced. Further, the present inventors have found that the specific gravity considering the content of the air can be measured according to the a method of cross-linked rubber-density measurement using JIS K6268 of buoyancy difference. Furthermore, the present inventors have found that by setting the pH to a specific value, the storage stability of the acrylic rubber bag can be further improved.
Further, the present inventors have found that by increasing the cooling rate after drying, the mooney scorch stability can be significantly improved without impairing the properties such as the roll processability, banbury processability, water resistance, strength properties, compression set resistance and the like of the acrylic rubber bag.
The present inventors have found that, by emulsifying a specific monomer component with water and an emulsifier, initiating emulsion polymerization in the presence of a redox catalyst comprising an inorganic radical generator such as potassium persulfate and a reducing agent, and adding a chain transfer agent in portions during the polymerization without adding the chain transfer agent in the beginning, and performing emulsion polymerization until the polymerization conversion becomes 90 wt% or more, a high molecular weight component and a low molecular weight component can be formed in the absolute molecular weight and the absolute molecular weight distribution of the acrylic rubber that can be produced as measured by GPC, a high molecular weight can be maintained and a wide molecular weight distribution can be formed, and the roll processability, crosslinkability, strength characteristics, and compression set resistance of the acrylic rubber bag are highly balanced.
The present inventors have found that by specifying the number of times of post-addition of the chain transfer agent in batches, the post-addition timing, the post-addition amount, the type of the chain transfer agent, the type of the reducing agent, the post-addition of the chain transfer agent in batches in addition to the reducing agent in the initial stage, the ratio of the amount of the reducing agent initially to the amount of the reducing agent added in the post-addition, and the polymerization temperature, it is possible to produce an acrylic rubber bag having a more balanced roll processability, strength characteristics, water resistance and compression set resistance.
Further, the present inventors have found that, when the emulsion polymerization liquid to which the chain transfer agent is added after the classification is solidified and dried, an acrylic rubber can be produced by melt-kneading and drying an acrylic rubber under high shear conditions using a specific extrusion dryer, whereby the roll processability, short-time crosslinkability, strength characteristics, and compression set resistance can be further improved.
The present inventors have further found that by blending carbon black and silica as fillers in the rubber composition comprising the acrylic rubber bag, filler and crosslinking agent of the present invention, the roll processability, banbury processability and short-time crosslinkability are excellent, and the crosslinked product is highly excellent in water resistance, strength characteristics and compression set resistance. The present inventors have found that, as the crosslinking agent, an organic compound, a polyvalent compound or an ionic crosslinking compound is preferable, and for example, by being a polyvalent ionic organic compound having a plurality of ion-reactive groups which react with ion-reactive groups of an acrylic rubber bag such as an amine group, an epoxy group, a carboxyl group or a thiol group, the roll processability, the banbury processability and the short-time crosslinkability are excellent, and the water resistance, the strength characteristics and the compression set resistance of the crosslinked product are highly excellent.
The present inventors have completed the present invention based on these findings.
Thus, according to the present invention, there is provided an acrylic rubber bag comprising an acrylic rubber having at least one reactive group selected from the group consisting of carboxyl groups, epoxy groups and chlorine atoms, having a weight average molecular weight (Mw) of 1000000 ～ 3500000 as measured by GPC-MALS method and an absolute molecular weight distribution, and having a ratio (Mw/Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) of 3.7 to 6.5, wherein the acrylic rubber bag has an methyl ethyl ketone insoluble content of 50% by weight or less, an ash content of 0.2% by weight or less and a total amount of sodium, magnesium, calcium, phosphorus and sulfur in the ash of 50% by weight or more.
In the acrylic rubber package of the present invention, the reactive group is preferably an ion-reactive group.
In the acrylic rubber bag of the present invention, the acrylic rubber is preferably composed of a binding unit derived from a (meth) acrylic acid ester selected from at least one of an alkyl (meth) acrylate and an alkoxyalkyl (meth) acrylate, a binding unit derived from a monomer having a reactive group selected from at least one of a carboxyl group, an epoxy group, and a chlorine atom, and a binding unit derived from another monomer used as needed.
In the acrylic rubber bag of the present invention, the amount of methyl ethyl ketone insoluble component is preferably 15% by weight or less.
In the acrylic rubber bag of the present invention, the values when the amount of the insoluble component of methyl ethyl ketone at 20 points is measured are preferably all within the range of (average value.+ -. 5% by weight).
In the acrylic rubber bag of the present invention, the specific gravity is preferably 0.9 or more.
In the acrylic rubber bag of the present invention, the pH is preferably 6 or less.
The acrylic rubber bag of the present invention is preferably produced by emulsion polymerization using a phosphate salt or a sulfate salt as an emulsifier, and is preferably produced by solidifying and drying a polymerization liquid obtained by emulsion polymerization using an alkali metal salt or a group 2 metal salt of the periodic table as a coagulant. The acrylic rubber bag of the present invention is preferably obtained by melt-kneading and drying after solidification, and preferably the melt-kneading and drying are carried out in a state substantially free from moisture, and the melt-kneading and drying are carried out under reduced pressure. The acrylic rubber bag of the present invention is preferably obtained by cooling at a cooling rate of 40℃per hour or more after the above-mentioned melt kneading and drying.
Further, according to the present invention, there is provided a method for producing an acrylic rubber bag, comprising the steps of: an emulsion step of emulsifying a monomer component with water and an emulsifier, wherein the monomer component contains a (meth) acrylate selected from at least one of an alkyl (meth) acrylate and an alkoxyalkyl (meth) acrylate, a monomer containing a reactive group selected from at least one of a carboxyl group, an epoxy group, and a chlorine atom, and optionally another copolymerizable monomer; an emulsion polymerization step of initiating emulsion polymerization in the presence of a redox catalyst comprising an inorganic radical generator and a reducing agent, adding a chain transfer agent and a reducing agent in batch during the polymerization, and continuing the emulsion polymerization until the polymerization conversion becomes 90 wt% or more to obtain an emulsion polymerization solution; a coagulation step of adding the emulsion polymerization liquid obtained into the stirred coagulation liquid to coagulate, thereby producing water-containing granules; a washing step of washing the produced hydrous pellets with hot water; a dehydration-drying-molding step of dehydrating the washed aqueous pellets with a dehydration barrel to a water content of 1 to 40 wt% and drying with a dryer barrel to a water content of less than 1 wt%, using a dryer barrel having a dehydration slit and a dryer barrel under reduced pressure and a screw type biaxial extrusion dryer having a die at the tip end, and extruding a sheet-like dried rubber from the die; and a step of rubber coating, in which the extruded sheet-like dry rubber is cut and laminated.
The method for producing an acrylic rubber bag of the present invention is preferably a method for producing an acrylic rubber bag of the present invention.
In the method for producing an acrylic rubber bag of the present invention, it is preferable that emulsion polymerization is performed in an emulsion polymerization step using a phosphate salt or a sulfate salt as an emulsifier.
In the method for producing an acrylic rubber bag of the present invention, it is preferable that the polymerization liquid produced in the emulsion polymerization step is coagulated and dried by using an alkali metal salt or a group 2 metal salt of the periodic table as a coagulant.
In the method for producing an acrylic rubber bag of the present invention, it is preferable that the polymerization liquid produced in the emulsion polymerization step is added to an aqueous solution containing a coagulant containing an alkali metal salt or a group 2 metal salt of the periodic table and stirred to coagulate the polymerization liquid.
In the method for producing an acrylic rubber bag of the present invention, it is preferable that the polymerization liquid produced in the emulsion polymerization step is brought into contact with a coagulant to be coagulated, and then melt kneaded and dried.
In the method for producing an acrylic rubber of the present invention, it is preferable that the melt kneading and drying are carried out in a state substantially free from moisture.
In the method for producing an acrylic rubber bag of the present invention, the above-mentioned melt kneading and drying are preferably carried out under reduced pressure.
In the method for producing an acrylic rubber bag of the present invention, the acrylic rubber after melt-kneading and drying is preferably cooled at a cooling rate of 40℃per hour or more.
In the method for producing an acrylic rubber bag of the present invention, it is preferable to wash, dehydrate and dry the aqueous pellet having a particle diameter in the range of 710 μm to 6.7mm in a proportion of 50 wt% or more.
Further, according to the present invention, there is also provided a rubber composition comprising a crosslinking agent, a filler, and a rubber component containing the above-mentioned acrylic rubber bag.
In the rubber composition of the present invention, the filler is preferably a reinforcing filler. In the rubber composition of the present invention, the filler is preferably carbon black. In the rubber composition of the present invention, the filler is preferably silica.
In the rubber composition of the present invention, the crosslinking agent is preferably an organic crosslinking agent. In the rubber composition of the present invention, the crosslinking agent is preferably a polyvalent compound. In the rubber composition of the present invention, it is preferable that the crosslinking agent is an ion-crosslinkable compound. In the rubber composition of the present invention, the crosslinking agent is preferably an ion-crosslinkable organic compound. In the rubber composition of the present invention, the crosslinking agent is preferably a polyionic organic compound.
In the rubber composition of the present invention, the ion of the ion-crosslinkable compound, ion-crosslinkable organic compound or polyion-crosslinkable organic compound as the crosslinking agent is preferably at least one ion-reactive group selected from the group consisting of an amino group, an epoxy group, a carboxyl group and a thiol group.
In the rubber composition of the present invention, the crosslinking agent is preferably a polyion compound selected from at least one of a polyamine compound, a polyepoxide compound, a polycarboxylic acid compound and a polythiol compound.
In the rubber composition of the present invention, the content of the crosslinking agent is preferably in the range of 0.001 to 20 parts by weight relative to 100 parts by weight of the rubber component.
The rubber composition of the present invention preferably further comprises an anti-aging agent. In the rubber composition of the present invention, the antioxidant is preferably an amine-based antioxidant.
Further, according to the present invention, there is provided a method for producing a rubber composition comprising mixing the rubber component comprising the acrylic rubber bag, a filler and an antioxidant, if necessary, and then mixing the mixture with a crosslinking agent.
Further, according to the present invention, there can be provided a crosslinked rubber product obtained by crosslinking the above-mentioned rubber composition. In the rubber crosslinked product of the present invention, the crosslinking of the rubber composition is preferably performed after molding. In the rubber crosslinked product of the present invention, it is preferable that the crosslinking of the rubber composition is performed by primary crosslinking and secondary crosslinking.
Effects of the invention
According to the present invention, there can be provided an acrylic rubber bag excellent in roll processability and banbury processability and having a high balance among water resistance, strength characteristics and compression set resistance of a crosslinked product, an efficient production method thereof, a high-quality rubber composition comprising the acrylic rubber bag, and a crosslinked rubber product obtained by crosslinking the composition.
Drawings
Fig. 1 is a diagram schematically showing an example of an acrylic rubber manufacturing system for manufacturing an acrylic rubber bag according to an embodiment of the present invention.
Fig. 2 is a view showing the structure of the screw extruder of fig. 1.
Fig. 3 is a diagram showing a structure of a transport type cooling device serving as the cooling device of fig. 1.
Detailed Description
The acrylic rubber bag of the present invention is characterized by comprising an acrylic rubber having at least one reactive group selected from the group consisting of carboxyl groups, epoxy groups and chlorine atoms, wherein the weight average molecular weight (Mw) in the absolute molecular weight and the absolute molecular weight distribution measured by GPC-MALS method is 1000000 ～ 3500000, the ratio (Mw/Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) is 3.7 to 6.5, the amount of methyl ethyl ketone insoluble component in the acrylic rubber bag is 50 wt.% or less, the amount of ash is 0.2 wt.% or less, and the total amount of sodium, magnesium, calcium, phosphorus and sulfur in the ash is 50 wt.% or more. The term "GPC-MALS method" as used herein refers to the following. GPC (gel permeation chromatography ) is a liquid chromatography method in which separation is performed based on differences in molecular size. The method comprises the following steps: a multi-angle laser light scattering instrument (MALS) and a differential refractive index instrument (RI) are assembled in the device, the light scattering intensity and the refractive index difference of a molecular chain solution which is classified by the size by a GPC device are measured according to the dissolution time, the molecular weight of a solute and the content thereof are sequentially calculated, and finally the absolute molecular weight distribution and the absolute average molecular weight value of a high molecular substance are obtained.
< reactive group >
The acrylic rubber bag of the present invention is characterized by having at least one reactive group selected from the group consisting of a carboxyl group, an epoxy group and a chlorine atom.
The reactive group selected from at least one of a carboxyl group, an epoxy group and a chlorine atom is not particularly limited, and is preferably a functional group that performs an ionic reaction, more preferably an epoxy group and a carboxyl group, particularly preferably a carboxyl group, and in this case, the crosslinkability in a short period of time and the compression set resistance and water resistance of the crosslinked product can be highly improved, and therefore, it is preferable.
The content of at least one reactive group selected from the group consisting of carboxyl groups, epoxy groups and chlorine atoms in the acrylic rubber bag of the present invention is not particularly limited, and may be appropriately selected depending on the purpose of use, and is usually in the range of 0.001 to 5% by weight, preferably in the range of 0.01 to 3% by weight, more preferably in the range of 0.05 to 1% by weight, and particularly preferably in the range of 0.1 to 0.5% by weight, and in this case, the processability, crosslinkability and the strength characteristics, compression set resistance, oil resistance, cold resistance, water resistance and other characteristics when a crosslinked product is produced are highly balanced, and therefore, it is preferable.
The acrylic rubber bag having at least one reactive group selected from the group consisting of a carboxyl group, an epoxy group and a chlorine atom of the present invention can introduce at least one reactive group selected from the group consisting of a carboxyl group, an epoxy group and a chlorine atom into an acrylic rubber by post-reaction, but it is preferable to copolymerize a monomer containing the reactive group.
< monomer component >
The monomer component constituting the acrylic rubber of the present invention is not particularly limited as long as it contains the above-mentioned reactive group and is a usual monomer constituting the acrylic rubber, but is preferably an acrylic rubber monomer component containing a monomer containing at least one reactive group selected from the group consisting of a carboxyl group, an epoxy group and a chlorine atom, more preferably a monomer component composed of at least one (meth) acrylate selected from the group consisting of an alkyl (meth) acrylate and an alkoxyalkyl (meth) acrylate, a monomer containing at least one reactive group selected from the group consisting of a carboxyl group, an epoxy group and a chlorine atom, and other copolymerizable monomers as necessary. In addition, in the present invention, "(meth) acrylate" is used as a term for esters of acrylic acid and/or methacrylic acid.
The alkyl (meth) acrylate is not particularly limited, and an alkyl (meth) acrylate having an alkyl group having 1 to 12 carbon atoms is generally used, and an alkyl (meth) acrylate having an alkyl group having 1 to 8 carbon atoms is preferably used, and an alkyl (meth) acrylate having an alkyl group having 2 to 6 carbon atoms is more preferably used.
Specific examples of the alkyl (meth) acrylate include: methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, n-hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, cyclohexyl (meth) acrylate, and the like, among which ethyl (meth) acrylate, n-butyl (meth) acrylate, more preferably ethyl acrylate, and n-butyl acrylate are preferable.
The alkoxyalkyl (meth) acrylate is not particularly limited, and an alkoxyalkyl (meth) acrylate having an alkoxyalkyl group having 2 to 12 carbon atoms is usually used, and an alkoxyalkyl (meth) acrylate having an alkoxyalkyl group having 2 to 8 carbon atoms is preferably used, and an alkoxyalkyl (meth) acrylate having an alkoxyalkyl group having 2 to 6 carbon atoms is more preferably used.
Specific examples of the alkoxyalkyl (meth) acrylate include: methoxymethyl (meth) acrylate, methoxyethyl (meth) acrylate, methoxypropyl (meth) acrylate, methoxybutyl (meth) acrylate, ethoxymethyl (meth) acrylate, ethoxyethyl (meth) acrylate, propoxyethyl (meth) acrylate, butoxyethyl (meth) acrylate, and the like. Among these, methoxyethyl (meth) acrylate, ethoxyethyl (meth) acrylate, and the like are preferable, and methoxyethyl acrylate and ethoxyethyl acrylate are more preferable.
At least one (meth) acrylic acid ester selected from these alkyl (meth) acrylate and alkoxyalkyl (meth) acrylate may be used alone or in combination of two or more, and the proportion thereof in the whole monomer components is usually in the range of 50 to 99.99% by weight, preferably in the range of 62 to 99.95% by weight, more preferably in the range of 74 to 99.9% by weight, particularly preferably in the range of 80 to 99.5% by weight, most preferably in the range of 87 to 99% by weight, and in this case, the acrylic rubber bag is excellent in weather resistance, heat resistance and oil resistance and is therefore preferable.
The monomer containing at least one reactive group selected from the group consisting of a carboxyl group, an epoxy group and a chlorine atom is not particularly limited, but is preferably a monomer having an ion-reactive group that participates in an ion reaction, more preferably a monomer having a carboxyl group and an epoxy group, and even more preferably a monomer having a carboxyl group, and in this case, the crosslinkability in a short period of time and compression set resistance and water resistance of a crosslinked product can be improved to a high degree, and therefore, it is preferable.
The monomer having a carboxyl group is not particularly limited, and an ethylenically unsaturated carboxylic acid can be preferably used. Examples of the ethylenically unsaturated carboxylic acid include: among these, ethylenically unsaturated monocarboxylic acid, ethylenically unsaturated dicarboxylic acid monoester and the like are particularly preferable because the compression set resistance when the acrylic rubber is coated into a rubber crosslinked product can be further improved.
The ethylenically unsaturated monocarboxylic acid is not particularly limited, but preferably has 3 to 12 carbon atoms, and examples thereof include acrylic acid, methacrylic acid, α -ethacrylic acid, crotonic acid, cinnamic acid, and the like.
The ethylenically unsaturated dicarboxylic acid is not particularly limited, but preferably an ethylenically unsaturated dicarboxylic acid having 4 to 12 carbon atoms, and examples thereof include: butenedioic acids such as fumaric acid and maleic acid; itaconic acid; citraconic acid, and the like. The ethylenically unsaturated dicarboxylic acid also includes ethylenically unsaturated dicarboxylic acids present as anhydrides.
The ethylenically unsaturated dicarboxylic acid monoester is not particularly limited, and examples thereof include monoesters of an alkyl group having 1 to 12 carbon atoms of an ethylenically unsaturated dicarboxylic acid having 4 to 12 carbon atoms, preferably monoesters of an alkyl group having 2 to 8 carbon atoms of an ethylenically unsaturated dicarboxylic acid having 4 to 6 carbon atoms, and more preferably monoesters of an alkyl group having 2 to 6 carbon atoms of a butenedioic acid having 4 carbon atoms.
Specific examples of the ethylenically unsaturated dicarboxylic acid monoester include: mono-alkyl butenedioates such as monomethyl fumarate, monoethyl fumarate, mono-n-butyl fumarate, monomethyl maleate, monoethyl maleate, mono-n-butyl maleate, monocyclopentyl fumarate, monocyclohexyl fumarate, monocyclohexenyl fumarate, monocyclopentyl maleate, monocyclohexyl maleate, and the like; mono-alkyl itaconates such as monomethyl itaconate, monoethyl itaconate, mono-n-butyl itaconate and monocyclohexyl itaconate, and among these, mono-n-butyl fumarate and mono-n-butyl maleate are preferable, and mono-n-butyl fumarate is particularly preferable.
Examples of the monomer having an epoxy group include: epoxy group-containing (meth) acrylates such as glycidyl (meth) acrylate; epoxy group-containing vinyl ethers such as allyl glycidyl ether and vinyl glycidyl ether.
The monomer having a chlorine atom is not particularly limited, and examples thereof include: unsaturated alcohol esters of saturated carboxylic acids having chlorine atoms, chloroalkyl (meth) acrylates, chloroacyloxy alkyl (meth) acrylates, (chloroacetylcarbamooxy) alkyl (meth) acrylates, unsaturated ethers having chlorine atoms, unsaturated ketones having chlorine atoms, chloromethyl aromatic vinyl compounds, unsaturated amides having chlorine atoms, chloroacetyl unsaturated monomers, and the like.
Specific examples of the unsaturated alcohol ester of a saturated carboxylic acid containing chlorine atom include: vinyl chloroacetate, vinyl 2-chloropropionate, allyl chloroacetate, and the like. Specific examples of the chloroalkyl (meth) acrylate include: chloromethyl (meth) acrylate, 1-chloroethyl (meth) acrylate, 2-chloroethyl (meth) acrylate, 1, 2-dichloroethyl (meth) acrylate, 2-chloropropyl (meth) acrylate, 3-chloropropyl (meth) acrylate, 2, 3-dichloropropyl (meth) acrylate, and the like. Specific examples of the chloroacyloxyalkyl (meth) acrylate include: 2- (chloroacetoxy) ethyl (meth) acrylate, 2- (chloroacetoxy) propyl (meth) acrylate, 3- (hydroxychloroacetoxy) propyl (meth) acrylate, and the like. Examples of the (chloroacetylcarbamoyloxy) alkyl (meth) acrylate include: 2- (chloroacetylcarbamoyloxy) ethyl (meth) acrylate, 3- (chloroacetylcarbamoyloxy) propyl (meth) acrylate, and the like. Specific examples of the unsaturated ether containing chlorine atom include: chloromethyl vinyl ether, 2-chloroethyl vinyl ether, 3-chloropropyl vinyl ether, 2-chloroethyl allyl ether, 3-chloropropyl allyl ether, and the like. Specific examples of the unsaturated ketone containing chlorine atom include: 2-chloroethyl vinyl ketone, 3-chloropropyl vinyl ketone, 2-chloroethyl allyl ketone, and the like. Specific examples of the chloromethyl aromatic vinyl compound include: p-chloromethylstyrene, m-chloromethylstyrene, o-chloromethylstyrene, p-chloromethyl-alpha-methylstyrene, etc. Specific examples of the unsaturated amide containing chlorine atom include: n-chloromethyl (meth) acrylamide, and the like. Further, specific examples of the chloracetyl unsaturated monomer include: 3- (hydroxychloroacetoxy) propyl allyl ether, p-vinylbenzyl chloroacetate, and the like.
These monomers containing at least one reactive group selected from the group consisting of a carboxyl group, an epoxy group and a chlorine atom may be used singly or in combination, and the proportion thereof in the total monomer components is usually in the range of 0.01 to 10% by weight, preferably in the range of 0.05 to 8% by weight, more preferably in the range of 0.1 to 6% by weight, particularly preferably in the range of 0.5 to 5% by weight, and most preferably in the range of 1 to 3% by weight.
The monomer other than the above, which can be used together with the above-mentioned monomers as needed (hereinafter, simply referred to as "other monomer") is not particularly limited as long as it is a monomer copolymerizable with the above-mentioned monomer, and examples thereof include: aromatic vinyl such as styrene, α -methylstyrene, divinylbenzene, etc.; ethylenically unsaturated nitriles such as acrylonitrile and methacrylonitrile; acrylamide monomers such as acrylamide and methacrylamide; olefin monomers such as ethylene, propylene, vinyl acetate, ethyl vinyl ether, butyl vinyl ether, and the like.
These other monomers may be used alone or in combination of two or more, and the proportion of the total monomer components is usually controlled in the range of 0 to 40% by weight, preferably in the range of 0 to 30% by weight, more preferably in the range of 0 to 20% by weight, particularly preferably in the range of 0 to 15% by weight, and most preferably in the range of 0 to 10% by weight.
< acrylic rubber >
The acrylic rubber constituting the acrylic rubber bag of the present invention has a reactive group, and is preferably composed of a combination unit of at least one (meth) acrylic acid ester selected from the group consisting of an alkyl (meth) acrylate and an alkoxyalkyl (meth) acrylate, a monomer containing at least one reactive group selected from the group consisting of a carboxyl group, an epoxy group and a chlorine atom, and other monomers, if necessary, in the acrylic rubber, and the respective proportions thereof are as follows: the binding unit derived from at least one (meth) acrylate selected from the group consisting of alkyl (meth) acrylate and alkoxyalkyl (meth) acrylate is usually in the range of 50 to 99.99% by weight, preferably in the range of 62 to 99.95% by weight, more preferably in the range of 74 to 99.9% by weight, particularly preferably in the range of 80 to 99.5% by weight, and most preferably in the range of 87 to 99% by weight; the binding unit derived from a monomer containing at least one reactive group selected from the group consisting of a carboxyl group, an epoxy group and a chlorine atom is usually in the range of 0.01 to 10% by weight, preferably in the range of 0.05 to 8% by weight, more preferably in the range of 0.1 to 6% by weight, particularly preferably in the range of 0.5 to 5% by weight, and most preferably in the range of 1 to 3% by weight; the binding unit derived from the other monomer is usually in the range of 0 to 40% by weight, preferably in the range of 0 to 30% by weight, more preferably in the range of 0 to 20% by weight, particularly preferably in the range of 0 to 15% by weight, and most preferably in the range of 0 to 10% by weight. When the monomer composition of the acrylic rubber is within this range, the acrylic rubber bag is preferred because of a high balance of properties such as short-time crosslinkability, compression set resistance, weather resistance, heat resistance, and oil resistance.
The measuring solvent for the GPC-MALS method for measuring the absolute molecular weight and the absolute molecular weight distribution of the acrylic rubber constituting the acrylic rubber package of the present invention is not particularly limited as long as it is capable of dissolving and measuring the acrylic rubber of the present invention, and a dimethylformamide-based solvent is preferable. The dimethylformamide-based solvent to be used is not particularly limited as long as it is a solvent containing dimethylformamide as a main component, and the ratio of dimethylformamide in the dimethylformamide-based solvent is 90% by weight, preferably 95% by weight, and more preferably 97% by weight or more. The compound to be added to dimethylformamide is not particularly limited, and in the present invention, a solution in which lithium chloride is added to dimethylformamide at a concentration of 0.05mol/L and 37% concentrated hydrochloric acid is added at a concentration of 0.01% is particularly preferable.
The weight average molecular weight (Mw) of the acrylic rubber constituting the acrylic rubber bag of the present invention is preferably in the range of 1000000 ～ 3500000, more preferably in the range of 1200000 ～ 3000000, even more preferably in the range of 1300000 ～ 3000000, particularly preferably in the range of 1500000 ～ 2500000, and most preferably in the range of 1900000 ～ 2100000, in terms of absolute molecular weight measured by GPC-MALS method, and in this case, the roll processability, strength characteristics and compression set resistance of the acrylic rubber bag are highly balanced. When the weight average molecular weight (Mw) of the acrylic rubber is too small, strength characteristics and compression set resistance are poor, whereas when the weight average molecular weight (Mw) of the acrylic rubber is too large, roll processability, banbury processability, injection moldability and the like are poor, which is not preferable.
The number average molecular weight (Mn) of the acrylic rubber constituting the acrylic rubber bag of the present invention is not particularly limited, and may be appropriately selected depending on the purpose of use, but the absolute molecular weight measured by GPC-MALS method is usually in the range of 100000 ～ 500000, preferably in the range of 200000 ～ 480000, more preferably in the range of 250000 ～ 450000, particularly preferably in the range of 300000 ～ 400000, and most preferably in the range of 350000 ～ 400000, and in this case, the roll processability, strength characteristics and compression set resistance of the acrylic rubber bag are highly balanced and therefore preferable. When the number average molecular weight (Mn) of the acrylic rubber is too small, the strength characteristics and compression set resistance are poor, whereas when the number average molecular weight (Mn) of the acrylic rubber is too large, the roll processability, banbury processability, injection moldability and the like are poor, which is not preferable.
The z-average molecular weight (Mz) of the acrylic rubber constituting the acrylic rubber bag of the present invention is not particularly limited, and is usually in the range of 1500000 ～ 6000000, preferably in the range of 2000000 ～ 5000000, more preferably in the range of 2500000 ～ 4500000, and particularly preferably in the range of 3000000 ～ 4000000, as measured by GPC-MALS method, and in this case, the roll processability, strength characteristics and compression set resistance of the acrylic rubber bag are highly balanced.
The ratio (Mw/Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) of the acrylic rubber constituting the acrylic rubber bag of the present invention is usually in the range of 3.7 to 6.5, preferably in the range of 3.8 to 6.2, more preferably in the range of 4 to 6, particularly preferably in the range of 4.5 to 5.7, most preferably in the range of 4.7 to 5.5, in terms of absolute molecular weight measured by GPC-MALS method, and in this case, the roll processability of the acrylic rubber bag, the strength characteristics after crosslinking and the compression set resistance are highly balanced, and therefore, it is preferable. When the ratio (Mw/Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) of the acrylic rubber is too small, the roll processability is poor, and when too large, the strength characteristics and compression set resistance are poor, and the roll processability becomes insufficient, which is not preferable.
The ratio (Mz/Mw) of the z-average molecular weight (Mz) to the weight-average molecular weight (Mw) of the acrylic rubber constituting the acrylic rubber bag of the present invention is not particularly limited, and may be appropriately selected depending on the purpose of use, and is usually in the range of 1.3 to 3, preferably in the range of 1.4 to 2.7, more preferably in the range of 1.5 to 2.5, particularly preferably in the range of 1.8 to 2, most preferably in the range of 1.8 to 1.95, in terms of the absolute molecular weight distribution in the high molecular weight region measured by GPC-MALS method, and in this case, the processability and strength characteristics of the acrylic rubber bag are highly balanced and the change in physical properties upon storage can be alleviated, and therefore is preferred.
The glass transition temperature (Tg) of the acrylic rubber constituting the acrylic rubber bag of the present invention may be appropriately selected depending on the purpose of use of the acrylic rubber, and is usually 20 ℃ or lower, preferably 10 ℃ or lower, more preferably 0 ℃ or lower, and in this case, processability and cold resistance are excellent, and therefore, it is preferable. The lower limit of the glass transition temperature (Tg) of the acrylic rubber is not particularly limited, but is usually-80℃or higher, preferably-60℃or higher, and more preferably-40℃or higher. By setting the glass transition temperature to the above lower limit or more, oil resistance and heat resistance can be further improved, and by setting the glass transition temperature to the above upper limit or less, processability, crosslinkability and cold resistance can be further improved.
< acrylic rubber bag >
The acrylic rubber bag of the present invention is characterized by comprising the acrylic rubber having the reactive group, wherein the amount of methyl ethyl ketone insoluble components is 50 wt% or less, the amount of ash is 0.2 wt% or less, and the total amount of sodium, magnesium, calcium, phosphorus and sulfur in the ash is 50 wt% or more.
The amount of insoluble components in the methyl ethyl ketone in the acrylic rubber bag of the present invention is preferably 50% by weight or less, more preferably 30% by weight or less, still more preferably 15% by weight or less, particularly preferably 10% by weight or less, and most preferably 5% by weight or less, and in this case, processability in kneading such as banbury is highly improved.
The value at which the amount of the insoluble component of methyl ethyl ketone at 20 points is arbitrarily measured in the acrylic rubber bag of the present invention is not particularly limited, but it is preferable that all the 20 points are within the range of (average value.+ -. 5) wt%, and preferably all the 20 points are within the range of (average value.+ -. 3) wt%, in which case there is no variation in processability, and the physical properties of the rubber composition and the rubber crosslinked product are stabilized. In addition, when the amount of the methyl ethyl ketone insoluble component at 20 points is arbitrarily measured in the acrylic rubber bag of the present invention, the values of all 20 points within the range of ±5 mean values means that the amount of the methyl ethyl ketone insoluble component at 20 points is all within the range of (mean value-5) to (mean value +5) wt%, and for example, when the mean value of the amount of the methyl ethyl ketone insoluble component at 20 wt%, the values of all 20 points are within the range of 15 to 25 wt%.
The acrylic rubber bag of the present invention is preferably an acrylic rubber bag obtained by melt-kneading and drying an aqueous pellet produced in a coagulation reaction in a state in which water is almost removed (water content of less than 1% by weight) by a screw type biaxial extrusion dryer, and in this case, the banbury processability and strength characteristics are highly balanced.
The ash content of the acrylic rubber bag of the present invention is preferably 0.2 wt% or less, more preferably 0.15 wt% or less, still more preferably 0.14 wt% or less, and even more preferably 0.13 wt% or less, and when in this range, the water resistance, strength characteristics and workability of the acrylic rubber bag are highly balanced.
The lower limit of the ash content of the acrylic rubber bag of the present invention is not particularly limited, and is appropriately selected depending on the purpose of use, but is usually 0.0001 wt% or more, preferably 0.0005 wt% or more, more preferably 0.001 wt% or more, particularly preferably 0.005 wt% or more, and most preferably 0.01 wt% or more, and in this case, the metal adhesion of the rubber is reduced and the handleability is excellent, which is preferable.
The ash content in the acrylic rubber bag of the present invention at the time of highly balancing the water resistance, strength characteristics, workability and handleability is usually in the range of 0.0001 to 0.2% by weight, preferably in the range of 0.0005 to 0.15% by weight, more preferably in the range of 0.001 to 0.14% by weight, particularly preferably in the range of 0.005 to 0.13% by weight, most preferably in the range of 0.01 to 0.13% by weight.
The total amount of sodium, magnesium, calcium, phosphorus and sulfur in the ash of the acrylic rubber bag of the present invention is usually 50% by weight or more, preferably 60% by weight or more, more preferably 70% by weight or more, particularly preferably 80% by weight or more, and most preferably 90% by weight or more, and in this case, the water resistance of the acrylic rubber bag is highly improved, and thus it is preferable. In addition, when the total amount of sodium, magnesium, calcium, phosphorus and sulfur in ash of the acrylic rubber bag of the present invention is in this range, metal adhesion is reduced and operability is excellent, so that it is preferable.
The total amount of magnesium and phosphorus in ash of the acrylic rubber bag of the present invention is not particularly limited, and is appropriately selected depending on the purpose of use, but is usually 30% by weight or more, preferably 50% by weight or more, more preferably 70% by weight or more, particularly preferably 80% by weight or more, and most preferably 90% by weight or more, and in this case, the water resistance, strength characteristics, and workability of the acrylic rubber bag are highly balanced, and therefore, it is preferable. In addition, when the total amount of magnesium and phosphorus in ash of the acrylic rubber bag of the present invention is in this range, metal adhesion is reduced, and operability is excellent, which is preferable.
The amount of magnesium in ash of the acrylic rubber bag of the present invention is not particularly limited, and may be appropriately selected depending on the purpose of use, and is usually 10% by weight or more, preferably 15 to 60% by weight, more preferably 20 to 50% by weight, particularly preferably 25 to 45% by weight, and most preferably 30 to 40% by weight.
The amount of phosphorus in the ash of the acrylic rubber bag of the present invention is not particularly limited and may be appropriately selected depending on the purpose of use, and is usually 10% by weight or more, preferably in the range of 20 to 90% by weight, more preferably in the range of 30 to 80% by weight, particularly preferably in the range of 40 to 70% by weight, and most preferably in the range of 50 to 60% by weight.
The ratio of magnesium to phosphorus ([ Mg ]/[ P ]) in ash of the acrylic rubber bag of the present invention is not particularly limited, and may be appropriately selected depending on the purpose of use, and is usually in the range of 0.4 to 2.5, preferably in the range of 0.45 to 1.2, more preferably in the range of 0.45 to 1, particularly preferably in the range of 0.5 to 0.8, and most preferably in the range of 0.55 to 0.7, and in this case, the water resistance, strength characteristics and workability of the acrylic rubber bag are highly balanced.
The ash in the acrylic rubber bag mainly comes from an emulsifier used for emulsion polymerization by emulsifying a monomer component and a coagulant used for coagulation of an emulsion polymerization liquid, and the total ash amount, the content of magnesium and phosphorus in the ash, and the like vary not only depending on the conditions of the emulsion polymerization step and the coagulation step but also depending on the conditions of the subsequent steps.
The acrylic rubber bag of the present invention is preferably used because it can highly improve mold releasability and workability in addition to water resistance and strength characteristics when an anionic emulsifier, a cationic emulsifier or a nonionic emulsifier is used, preferably an anionic emulsifier, and more preferably a phosphate or sulfate salt is used as an emulsifier in emulsion polymerization described later. The water resistance of the acrylic rubber bag is uniquely related to the ash content in the acrylic rubber and the total amount of sodium, magnesium, calcium, phosphorus and sulfur in the ash, and the use of the above-mentioned emulsifier is preferable because the water resistance, strength characteristics, mold releasability and workability of the acrylic rubber bag can be further highly balanced.
The acrylic rubber bag of the present invention is preferably a metal salt, preferably an alkali metal salt or a metal salt of group 2 of the periodic table, as a coagulant to be described later, since the mold releasability and workability can be improved to a high degree in addition to the water resistance and strength characteristics. The water resistance of the acrylic rubber bag is uniquely related to the ash content in the acrylic rubber and the total amount of sodium, magnesium, calcium, phosphorus and sulfur in the ash, and the use of the above-described coagulant is preferable because the water resistance, strength characteristics, mold releasability and workability of the acrylic rubber bag can be more highly balanced.
The specific gravity of the acrylic rubber bag of the present invention is not particularly limited, but is usually 0.7 or more, preferably 0.8 or more, more preferably 0.9 or more, particularly preferably 0.95 or more, and most preferably 1 or more, and in this case, air is hardly present in the interior, and the storage stability is excellent, and therefore, it is preferable. The specific gravity of the acrylic rubber bag of the present invention is usually in the range of 0.7 to 1.6, preferably in the range of 0.8 to 1.5, more preferably in the range of 0.9 to 1.4, particularly preferably in the range of 0.95 to 1.3, and most preferably in the range of 1.0 to 1.2, and in this case, productivity, storage stability, crosslinking properties, stability, and the like of the crosslinked product are highly balanced, and thus are preferable. When the specific gravity of the acrylic rubber bag is too small, it means that the amount of air in the acrylic rubber bag is large, and that the storage stability is greatly affected, including oxidative deterioration and the like, and is not preferable.
The specific gravity of the acrylic rubber bag of the present invention is the specific gravity of the mass divided by the volume including voids, that is, the specific gravity of the mass divided by the buoyancy measured in air, and is usually the specific gravity measured by the a method according to JIS K6268 crosslinked rubber-density measurement.
The acrylic rubber bag of the present invention is preferably obtained by drying the aqueous pellets produced in the coagulation reaction by a screw type biaxial extrusion dryer under reduced pressure or melt kneading and drying under reduced pressure, because the characteristics such as storage stability, roll processability and strength characteristics are particularly excellent and highly balanced.
The complex viscosity ([ eta ]60 ℃) of the acrylic rubber bag of the present invention at 60℃is not particularly limited, and is suitably selected depending on the purpose of use, but is usually not more than 15000[ Pa.s ], preferably in the range of 1000 to 10000[ Pa.s ], more preferably in the range of 2000 to 5000[ Pa.s ], particularly preferably in the range of 2500 to 4000[ Pa.s ], most preferably in the range of 2500 to 3000[ Pa.s ], and in this case, the processability, oil resistance and shape retention are excellent.
The complex viscosity ([ eta ]100 ℃) of the acrylic rubber bag of the present invention at 100℃is not particularly limited, and is suitably selected depending on the purpose of use, but is usually in the range of 1500 to 6000[ Pa.s ], preferably in the range of 2000 to 5000[ Pa.s ], more preferably in the range of 2300 to 4000[ Pa.s ], particularly preferably in the range of 2500 to 3500[ Pa.s ], most preferably in the range of 2500 to 3000[ Pa.s ], and in this case, the processability, oil resistance and shape retention are excellent.
The ratio of the complex viscosity at 100 ℃ ([ eta ]100 ℃) to the complex viscosity at 60 ℃ ([ eta ]60 ℃) of the acrylic rubber package of the present invention ([ eta ]100 ℃/[ eta ]60 ℃) is not particularly limited, and may be appropriately selected depending on the purpose of use, and is usually 0.5 or more, preferably 0.6 or more, more preferably 0.7 or more, particularly preferably 0.8 or more, and most preferably 0.83 or more. The ratio of the complex viscosity at 100 ℃ ([ eta ]100 ℃) to the complex viscosity at 60 ℃ ([ eta ]60 ℃) of the acrylic rubber package of the present invention ([ eta ]100 ℃/[ eta ]60 ℃) is usually in the range of 0.5 to 0.99, preferably in the range of 0.6 to 0.98, more preferably in the range of 0.7 to 0.97, particularly preferably in the range of 0.8 to 0.96, most preferably in the range of 0.85 to 0.95, and in this case, the processability, oil resistance and shape retention are highly balanced.
The water content of the acrylic rubber bag of the present invention is not particularly limited, and may be appropriately selected depending on the purpose of use, but is usually less than 1% by weight, preferably 0.8% by weight or less, more preferably 0.6% by weight or less, and in this case, the vulcanization characteristics of the acrylic rubber bag are optimized, and the characteristics such as heat resistance and water resistance are highly improved, and therefore, it is preferable.
The pH of the acrylic rubber bag of the present invention is not particularly limited, and is preferably selected appropriately according to the purpose of use, and is usually 6 or less, preferably in the range of 2 to 6, more preferably in the range of 2.5 to 5.5, and most preferably in the range of 3 to 5, and in this case, the storage stability of the acrylic rubber bag is highly improved.
The Mooney viscosity (ML1+4, 100 ℃) of the acrylic rubber bag of the present invention is not particularly limited, and is appropriately selected depending on the purpose of use, and is usually in the range of 10 to 150, preferably 20 to 100, more preferably 25 to 70, and in this case, the processability and strength characteristics of the acrylic rubber bag are highly balanced.
The acrylic rubber content of the above-described structure of the acrylic rubber bag of the present invention is almost an acrylic rubber, and is preferably 90% by weight or more, preferably 95% by weight or more, more preferably 97% by weight or more, since the strength characteristics and the workability of rolls and the like are highly balanced in this case, which is appropriately selected depending on the purpose of use. In addition, the content of the acrylic rubber in the acrylic rubber bag was estimated by subtracting the value of the ash amount from the weight of the acrylic rubber bag.
The size of the acrylic rubber bag of the present invention is not particularly limited, and may be appropriately selected depending on the purpose of use, and the width is usually in the range of 100 to 800mm, preferably in the range of 200 to 500mm, more preferably in the range of 250 to 450mm, the length is usually in the range of 300 to 1200mm, preferably in the range of 400 to 1000mm, more preferably in the range of 500 to 800mm, and the height (thickness) is usually in the range of 50 to 500mm, preferably in the range of 100 to 300mm, more preferably in the range of 150 to 250mm, and the above ranges are appropriate. The shape of the acrylic rubber bag of the present invention is not limited, and may be appropriately selected depending on the purpose of use of the acrylic rubber bag, and in many cases, a rectangular parallelepiped shape is preferable.
< method for producing acrylic rubber bag >
The method for producing the acrylic rubber bag is not particularly limited, and for example, the acrylic rubber bag can be easily produced by a method comprising the steps of: an emulsifying step of emulsifying a monomer component containing at least one (meth) acrylic acid ester selected from the group consisting of alkyl (meth) acrylates and alkoxyalkyl (meth) acrylates, a monomer containing at least one reactive group selected from the group consisting of carboxyl groups, epoxy groups and chlorine atoms, and, if necessary, another copolymerizable monomer with water and an emulsifier; an emulsion polymerization step of initiating emulsion polymerization in the presence of a redox catalyst comprising an inorganic radical generator and a reducing agent, adding a chain transfer agent and a reducing agent in batch during the polymerization, and continuing the emulsion polymerization until the polymerization conversion becomes 90 wt% or more to obtain an emulsion polymerization solution; a coagulation step of adding the emulsion polymerization liquid obtained to the stirred coagulation liquid to coagulate, thereby producing water-containing pellets; a washing step of washing the produced hydrous pellets with hot water; a dehydration, drying and molding step of dehydrating the washed aqueous pellets with a dehydration barrel to a water content of 1 to 40 wt% and drying with a dryer barrel to a water content of less than 1 wt%, using a dryer barrel having a dehydration slit, a dryer barrel under reduced pressure, and a screw type biaxial extrusion dryer having a die at the tip, and extruding a sheet-like dried rubber from the die; and a rubber packing step of cutting the extruded sheet-like dry rubber and laminating the cut sheet-like dry rubber.
(monomer component)
The monomer components used in the present invention are the same as the examples and preferred ranges of the monomer components already described. As already described, the amount of the monomer component used may be appropriately selected so that the composition of the acrylic rubber constituting the acrylic rubber bag of the present invention becomes the composition in emulsion polymerization.
(emulsifier)
The emulsifier used in the present invention is not particularly limited, and examples thereof include: anionic emulsifiers, cationic emulsifiers, nonionic emulsifiers, and the like, and anionic emulsifiers are preferred.
The anionic emulsifier is not particularly limited, and examples thereof include: salts of fatty acids such as myristic acid, palmitic acid, oleic acid, and linolenic acid; alkylbenzene sulfonates such as sodium dodecylbenzene sulfonate; sulfate salts such as sodium lauryl sulfate, phosphate salts such as polyoxyalkylene alkyl ether phosphate salts; alkyl sulfosuccinates, and the like. Among these anionic emulsifiers, phosphate salts and sulfate salts are preferable, phosphate salts are particularly preferable, and 2-valent phosphate salts are most preferable, since the water resistance, strength characteristics, mold releasability and workability of the resulting acrylic rubber bag can be highly balanced. The phosphate and sulfate are preferably alkali metal salts of phosphate and sulfate, and more preferably sodium salts of phosphate and sulfate, and in this case, the water resistance, strength characteristics, mold release properties, and workability of the resulting acrylic rubber bag can be highly balanced, and thus are preferable.
The 2-valent phosphate is not particularly limited as long as it is a phosphate that can be used as an emulsifier in emulsion polymerization, and examples thereof include: alkoxy polyoxyalkylene phosphate, alkylphenoxy polyoxyalkylene phosphate, and the like, among these, metal salts thereof are preferred, alkali metal salts thereof are more preferred, and sodium salts thereof are most preferred.
Examples of the alkoxypolyoxyalkylene phosphate include: among these, alkoxypolyoxyethylene phosphate salts are preferable, such as alkoxypolyoxyethylene phosphate salts and alkoxypolyoxypropylene phosphate salts.
Specific examples of the alkoxypolyoxyethylene phosphate salt include: among these alkali metal salts, especially alkali metal salts of these are preferred octoxydioxyethylene phosphate, octoxytrioxyethylene phosphate, octoxytetraethylene phosphate, decoxytetraethylene phosphate, dodecoxytetraethylene phosphate, tridecyloxytetraethylene phosphate, tetradecyloxytetraethylene phosphate, hexadecyloxytetraethylene phosphate, octadecyl tetraethylene phosphate, octoxypentaethylene phosphate, decoxypentaethylene phosphate, dodecoxypentaethylene phosphate, tridecyloxypentaethylene phosphate, tetradecyloxy pentaethylene phosphate, hexadecyloxy pentaethylene phosphate, octadecyl pentaethylene phosphate, octoxyhexaethylene phosphate, decyloxy hexaethylene phosphate, dodecoxyhexaethylene phosphate, tridecyloxyhexaethylene phosphate, tetradecyloxy hexaethylene phosphate, hexadecyloxy hexaethylene phosphate, octadecyl hexaethylene phosphate, octoxyoctaethylene phosphate, decyloxy octaethylene phosphate, dodecoxyoctaethylene phosphate, tridecyloxyoctaethylene phosphate, tetradecyloxy octaethylene phosphate, hexadecyloxy octaethylene phosphate, and the like.
Specific examples of the alkoxypolyoxypropylene phosphate salt include: octyloxydioxypropene phosphate, octyloxytrioxypropene phosphate, octyloxytetraoxypropylene phosphate, decyloxy tetraoxypropylene phosphate, dodecyloxytetraoxypropylene phosphate, tridecyloxytetraoxypropylene phosphate, tetradecyloxy tetraoxypropylene phosphate, hexadecyloxy tetraoxypropylene phosphate, octadecyloxypropylene phosphate, octyloxypentaoxypropylene phosphate, decyloxy pentaoxypropylene phosphate, dodecyloxypentaoxypropylene phosphate, tridecyloxypentaoxypropylene phosphate, tetradecyloxy pentaoxypropylene phosphate, hexadecyloxy pentaoxypropylene phosphate, octadecyloxypentaoxypropylene phosphate, octyloxypropylene phosphate, decyloxy hexaoxypropylene phosphate, dodecyloxypropylene phosphate, tridecyloxy hexaoxypropylene phosphate, tetradecyloxy hexaoxypropylene phosphate, hexadecyloxy hexaoxypropylene phosphate, octadecyloxy hexapropylene phosphate, octoyloxy octapropylene phosphate, decyloxy octapropylene phosphate, tridecyloxy octaoxypropylene phosphate, tetradecyloxy octapropylene phosphate, hexadecyloxy octapropylene phosphate, octadecyl octapropylene phosphate, and the like, among these, alkali metal salts thereof, particularly sodium salts, are preferred.
Specific examples of the alkylphenoxypolyoxyalkylene phosphate salt include: alkylphenoxypolyoxyethylene phosphate, alkylphenoxypolyoxypropylene phosphate, and the like, and among these, alkylphenoxypolyoxyethylene phosphate is preferable.
Specific examples of the alkylphenoxypolyoxyethylene phosphate salt include: metal salts of methylphenoxy tetraoxyethylene phosphate, ethylphenoxy tetraoxyethylene phosphate, butylphenoxy tetraoxyethylene phosphate, hexylphenoxy tetraoxyethylene phosphate, nonylphenoxy tetraoxyethylene phosphate, dodecylphenoxy tetraoxyethylene phosphate, octadecylphenoxy tetraoxyethylene phosphate, methylphenoxy pentaoxyethylene phosphate, ethylphenoxy pentaoxyethylene phosphate, butylphenoxy pentaoxyethylene phosphate, hexylphenoxy pentaoxyethylene phosphate, nonylphenoxy pentaoxyethylene phosphate, dodecylphenoxy pentaoxyethylene phosphate, methylphenoxy hexaoxyethylene phosphate, ethylphenoxy hexaoxyethylene phosphate, butylphenoxy hexaoxyethylene phosphate, hexylphenoxy hexaoxyethylene phosphate, nonylphenoxy hexaoxyethylene phosphate, dodecylphenoxy hexaoxyethylene phosphate, methylphenoxy hexaoxyethylene phosphate, ethylphenoxy octaoxyethylene phosphate, butylphenoxy octaoxyethylene phosphate, hexylphenoxy octaoxyethylene phosphate, nonylphenoxy octaoxyethylene phosphate, dodecylphenoxy octaoxyethylene phosphate, etc., among these, alkali metal salts, especially sodium salts thereof are preferred.
Specific examples of the alkylphenoxypolyoxypropylene phosphate salt include: metal salts such as methylphenoxy tetraoxypropylene phosphate, ethylphenoxy tetraoxypropylene phosphate, butylphenoxy tetraoxypropylene phosphate, hexylphenoxy tetraoxypropylene phosphate, nonylphenoxy tetraoxypropylene phosphate, dodecylphenoxy tetraoxypropylene phosphate, methylphenoxy pentaoxypropylene phosphate, ethylphenoxy pentaoxypropylene phosphate, butylphenoxy pentaoxypropylene phosphate, hexylphenoxy pentaoxypropylene phosphate, nonylphenoxy pentaoxypropylene phosphate, dodecylphenoxy pentaoxypropylene phosphate, methylphenoxy hexaoxypropylene phosphate, ethylphenoxy hexaoxypropylene phosphate, butylphenoxy hexaoxypropylene phosphate, hexylphenoxy hexaoxypropylene phosphate, nonylphenoxy hexaoxypropylene phosphate, dodecylphenoxy hexaoxypropylene phosphate, methylphenoxy octaoxypropylene phosphate, ethylphenoxy octaoxypropylene phosphate, butylphenoxy octaoxypropylene phosphate, hexylphenoxy octaoxypropylene phosphate, nonylphenoxy octaoxypropylene phosphate, dodecylphenoxy octaoxypropylene phosphate, and the like, and alkali metal salts thereof, particularly sodium salts thereof, are preferred.
As the phosphate salt, a 1-valent phosphate salt such as a sodium salt of di (alkoxypolyoxyalkylene) phosphate can be used alone or in combination with a 2-valent phosphate salt.
Examples of the sulfate salt include: sodium lauryl sulfate, potassium lauryl sulfate, ammonium lauryl sulfate, sodium myristyl sulfate, sodium polyoxyethylene alkyl sulfate, sodium polyoxyethylene alkylaryl sulfate, and the like, with sodium lauryl sulfate being preferred.
Examples of the cationic emulsifier include: alkyl trimethyl ammonium chloride, dialkyl ammonium chloride, benzyl ammonium chloride, and the like.
Examples of the nonionic emulsifier include: polyoxyalkylene fatty acid esters such as polyoxyethylene stearate; polyoxyalkylene alkyl ethers such as polyoxyethylene lauryl ether; polyoxyalkylene alkylphenol ethers such as polyoxyethylene nonylphenyl ether; the polyoxyethylene sorbitan alkyl ester is preferably a polyoxyalkylene alkyl ether or a polyoxyalkylene alkylphenol ether, and more preferably a polyoxyethylene alkyl ether or a polyoxyethylene alkylphenol ether.
These emulsifiers may be used alone or in combination of two or more, and the amount thereof is usually in the range of 0.01 to 10 parts by weight, preferably in the range of 0.1 to 5 parts by weight, more preferably in the range of 1 to 3 parts by weight, relative to 100 parts by weight of the monomer component.
The method (mixing method) of mixing the monomer component, water and emulsifier may be a conventional method, and examples thereof include a method of stirring the monomer, emulsifier and water using a stirrer such as a homogenizer or a disk turbine. The amount of water used is usually in the range of 1 to 1000 parts by weight, preferably in the range of 5 to 500 parts by weight, more preferably in the range of 4 to 300 parts by weight, particularly preferably in the range of 3 to 150 parts by weight, and most preferably in the range of 20 to 80 parts by weight, relative to 100 parts by weight of the monomer component.
(inorganic radical generator)
The polymerization catalyst used in the present invention is characterized by using a redox catalyst comprising an inorganic radical generator and a reducing agent. In particular, the use of an inorganic radical generator is preferable because the workability of the produced acrylic rubber can be improved to a high degree.
The inorganic radical generator is not particularly limited as long as it is an inorganic radical generator generally used in emulsion polymerization, and examples thereof include: among these, persulfates such as sodium persulfate, potassium persulfate, ammonium persulfate, etc., hydrogen peroxide, etc., are preferable, and potassium persulfate and ammonium persulfate are more preferable, and potassium persulfate is particularly preferable.
These inorganic radical generators may be used singly or in combination of two or more kinds, and the amount thereof is usually in the range of 0.0001 to 5 parts by weight, preferably in the range of 0.0005 to 1 part by weight, more preferably in the range of 0.001 to 0.25 part by weight, particularly preferably in the range of 0.01 to 0.21 part by weight, and most preferably in the range of 0.1 to 0.2 part by weight, relative to 100 parts by weight of the monomer component.
(reducing agent)
The reducing agent used in the present invention is not particularly limited as long as it is a reducing agent generally used in emulsion polymerization, and at least two reducing agents are preferably used, and a metal ion compound in a reduced state and the other reducing agents are preferably combined because it can more highly balance the banbury workability and roll workability and strength characteristics of the resulting acrylic rubber bag.
The metal ion compound in the reduced state is not particularly limited, and examples thereof include: among them, ferrous sulfate, sodium iron hexamethylenediamine tetraacetate, cuprous naphthenate and the like are preferable. These metal ion compounds in a reduced state may be used singly or in combination of two or more, and the amount thereof is usually in the range of 0.000001 to 0.01 parts by weight, preferably in the range of 0.00001 to 0.001 parts by weight, more preferably in the range of 0.00005 to 0.0005 parts by weight, relative to 100 parts by weight of the monomer component.
The reducing agent other than the metal ion compound in the reduced state used in the present invention is not particularly limited, and examples thereof include: ascorbic acid or its salts such as ascorbic acid, sodium ascorbate, potassium ascorbate, etc.; erythorbic acid or salts thereof such as erythorbic acid, sodium erythorbate, and potassium erythorbate; sulfinate salts such as sodium hydroxymethanesulfinate; sulfite such as sodium sulfite, potassium sulfite, sodium bisulfite, sodium aldehyde bisulfite, potassium bisulfite, etc.; metabisulfites such as sodium metabisulfite, potassium metabisulfite, sodium metabisulfite, potassium metabisulfite and the like; thiosulfate such as sodium thiosulfate and potassium thiosulfate; phosphorous acid or salts thereof such as phosphorous acid, sodium phosphite, potassium phosphite, sodium hydrogen phosphite, potassium hydrogen phosphite, etc.; pyrophosphorous acid or salts thereof such as pyrophosphorous acid, sodium pyrophosphate, potassium pyrophosphate, sodium hydrogen pyrophosphate, potassium hydrogen pyrophosphate, etc.; sodium formaldehyde sulfoxylate, and the like. Among these, ascorbic acid or a salt thereof, sodium formaldehyde sulfoxylate, and the like are preferable, and ascorbic acid or a salt thereof is particularly preferable.
These reducing agents other than the metal ion compound in the reduced state may be used singly or in combination of two or more, and the amount thereof is usually in the range of 0.001 to 1 part by weight, preferably in the range of 0.005 to 0.5 part by weight, more preferably in the range of 0.01 to 0.1 part by weight, relative to 100 parts by weight of the monomer component.
The preferred combination of the metal ion compound in the reduced state and the reducing agent other than it is a combination of ferrous sulfate and ascorbic acid or a salt thereof and/or sodium formaldehyde sulfoxylate, more preferably a combination of ferrous sulfate and ascorbate or a salt thereof. In this case, the amount of the ferrous sulfate to be used is usually in the range of 0.000001 to 0.01 parts by weight, preferably in the range of 0.00001 to 0.001 parts by weight, more preferably in the range of 0.00005 to 0.0005 parts by weight, relative to 100 parts by weight of the monomer component, and the amount of the ascorbic acid or a salt thereof and/or sodium formaldehyde sulfoxylate to be used is usually in the range of 0.001 to 1 part by weight, preferably in the range of 0.005 to 0.5 parts by weight, more preferably in the range of 0.01 to 0.1 part by weight.
The amount of water used in the emulsion polymerization may be only the amount used in the emulsification of the monomer component, or may be adjusted to be usually in the range of 10 to 1000 parts by weight, preferably in the range of 50 to 500 parts by weight, more preferably in the range of 80 to 400 parts by weight, and most preferably in the range of 100 to 300 parts by weight, relative to 100 parts by weight of the monomer component used for the polymerization.
The emulsion polymerization may be carried out by a conventional method, and may be carried out in any of batch, semi-batch, and continuous modes. The polymerization temperature and polymerization time are not particularly limited, and may be appropriately selected depending on the kind of the polymerization initiator used, and the like. The polymerization time is usually 0.5 to 100 hours, preferably 1 to 10 hours.
The emulsion polymerization is exothermic, and the polymerization reaction can be shortened by increasing the temperature when not controlled, but in the present invention, the emulsion polymerization temperature is usually controlled to 35℃or less, preferably 0 to 35℃and more preferably 5 to 30℃and particularly preferably 10 to 25℃and the strength characteristics of the produced acrylic rubber bag are highly balanced with the processability in kneading such as Banbury.
(post addition of chain transfer agent)
In the present invention, it is preferable that the chain transfer agent is added in batch during the polymerization without adding the chain transfer agent at the beginning, because the acrylic rubber having a high molecular weight component and a low molecular weight component separated from each other can be produced, and the strength characteristics of the produced acrylic rubber bag and the processability at the time of kneading such as rolls are highly balanced.
The chain transfer agent to be used is not particularly limited as long as it is a chain transfer agent generally used in emulsion polymerization, and, for example, a thiol compound can be preferably used.
As the thiol compound, an alkyl thiol compound having 2 to 20 carbon atoms can be generally used, and an alkyl thiol compound having 5 to 15 carbon atoms is preferably used, and an alkyl thiol compound having 6 to 14 carbon atoms is more preferably used.
The alkyl thiol compound may be any of an n-alkyl thiol compound, a secondary alkyl thiol compound, and a tertiary alkyl thiol compound, and is preferably an n-alkyl thiol compound or a tertiary alkyl thiol compound, and more preferably an n-alkyl thiol compound, and in this case, the effect of the chain transfer agent can be stably exhibited, and the processability of the produced acrylic rubber bag such as a roller can be highly improved, which is preferable.
Specific examples of the alkyl thiol compound include: n-pentylmercaptan, n-hexylthiol, n-heptylthiol, n-octylthiol, n-decylthiol, n-dodecylthiol, n-tridecylthiol, n-tetradecylthiol, n-hexadecylthiol, n-octadecylthiol, sec-pentylmercaptan, sec-hexylthiol, sec-heptylthiol, sec-octylthiol, zhong Guiji thiol, sec-dodecylthiol, sec-tridecylthiol, sec-tetradecylthiol, sec-hexadecylthiol, sec-octadecylthiol, tert-pentylmercaptan, tert-hexylthiol, tert-heptylthiol, tert-octylthiol, tert-decylthiol, tert-dodecylthiol, tert-tridecylthiol, tert-tetradecylthiol, tert-hexadecylthiol, tert-octadecylthiol, etc., preferably n-octylthiol, n-dodecylthiol, tert-dodecylthiol, more preferably n-octylthiol, n-dodecylthiol.
These chain transfer agents can be used either individually or in combination of two or more. The amount of the chain transfer agent used is not particularly limited, but is usually in the range of 0.0001 to 1 part by weight, preferably in the range of 0.0005 to 0.5 part by weight, more preferably in the range of 0.001 to 0.5 part by weight, particularly preferably in the range of 0.005 to 0.1 part by weight, most preferably in the range of 0.01 to 0.06 part by weight, based on 100 parts by weight of the monomer component, and in this case, the strength characteristics and roll processability of the produced acrylic rubber bag are highly balanced, and thus are preferable.
In the present invention, it is preferable to add the chain transfer agent in a batch manner during the polymerization without adding the chain transfer agent at the beginning of the polymerization, since the high molecular weight component and the low molecular weight component of the acrylic rubber can be produced, and the molecular weight distribution is set to a specific range, so that the strength characteristics and the processability of rolls and the like are highly balanced.
The number of times of post-addition of the chain transfer agent in batches is not particularly limited, and may be appropriately selected depending on the purpose of use, and is usually 1 to 5 times, preferably 2 to 4 times, more preferably 2 to 3 times, and particularly preferably 2 times, and in this case, the strength characteristics of the produced acrylic rubber bag and the workability of rolls and the like can be highly balanced, and thus are preferable.
The timing of starting the batch-wise post-addition of the chain transfer agent is not particularly limited, and may be appropriately selected depending on the purpose of use, and is usually in the range of 20 minutes or later, preferably 30 minutes or later, more preferably 30 to 200 minutes, particularly preferably 35 to 150 minutes, and most preferably 40 to 120 minutes after the initiation of polymerization, and in this case, the strength characteristics of the produced acrylic rubber bag and the workability of the roll or the like can be highly balanced, and thus are preferable.
The amount of the chain transfer agent added in each of the batch-wise post-addition is not particularly limited, and may be appropriately selected depending on the purpose of use, but is usually in the range of 0.00005 to 0.5 parts by weight, preferably in the range of 0.0001 to 0.1 parts by weight, more preferably in the range of 0.0005 to 0.05 parts by weight, particularly preferably in the range of 0.001 to 0.03 parts by weight, and most preferably in the range of 0.002 to 0.02 parts by weight, based on 100 parts by weight of the monomer component, and in this case, the strength characteristics and roll processability of the produced acrylic rubber bag can be highly balanced, and thus it is preferable.
After the addition of the chain transfer agent, the polymerization reaction may be continued for usually 30 minutes or more, preferably 45 minutes or more, more preferably 1 hour or more, and then the polymerization reaction may be ended.
(post addition of reducing agent)
In the present invention, the reducing agent of the redox catalyst can be added after the polymerization, and thus the strength characteristics of the produced acrylic rubber bag and the workability of rolls and the like can be highly balanced, which is preferable.
The reducing agent added after the polymerization is the same as the above-mentioned examples and preferable ranges of the reducing agent. In the present invention, as the reducing agent to be added later, ascorbic acid or a salt thereof is preferable.
The amount of the reducing agent to be added after the polymerization is not particularly limited, and may be appropriately selected depending on the purpose of use, but is usually in the range of 0.0001 to 1 part by weight, preferably in the range of 0.0005 to 0.5 part by weight, more preferably in the range of 0.001 to 0.5 part by weight, particularly preferably in the range of 0.005 to 0.1 part by weight, and most preferably in the range of 0.01 to 0.05 part by weight, based on 100 parts by weight of the monomer component, and in this case, the productivity of the production of the acrylic rubber bag is excellent, and the strength characteristics and workability of the produced acrylic rubber bag can be highly balanced, and thus it is preferable.
The reducing agent added after the polymerization may be added continuously or batchwise, preferably batchwise. The number of times of adding the reducing agent after it is batchwise during the polymerization is not particularly limited, but is usually 1 to 5 times, preferably 1 to 3 times, more preferably 1 to 2 times.
When the reducing agent added after the initiation of polymerization and during the polymerization is ascorbic acid or a salt thereof, the ratio of the amount of the initially added ascorbic acid or a salt thereof to the amount of the subsequently added ascorbic acid or a salt thereof is not particularly limited, and the weight ratio of "the initially added ascorbic acid or a salt thereof"/"the batchwise subsequently added ascorbic acid or a salt thereof" is usually in the range of 1/9 to 8/2, preferably in the range of 2/8 to 6/4, more preferably in the range of 3/7 to 5/5, and in this case, the productivity of the production of the acrylic rubber bag is excellent, and the strength characteristics and the workability of the produced acrylic rubber bag can be highly balanced, and therefore, it is preferable.
The timing of the post-addition of the reducing agent is not particularly limited, and may be appropriately selected depending on the purpose of use, and is usually in the range of 1 to 3 hours after the start of polymerization, preferably in the range of 1.5 to 2.5 hours after the start of polymerization, and in this case, the productivity of the production of the acrylic rubber bag is excellent, and the strength characteristics of the produced acrylic rubber bag and the workability of rolls and the like can be highly balanced, which is preferable.
The amount of the reducing agent added in each of the batch-wise post-addition is not particularly limited, and may be appropriately selected depending on the purpose of use, but is usually in the range of 0.00005 to 0.5 parts by weight, preferably in the range of 0.0001 to 0.1 parts by weight, more preferably in the range of 0.0005 to 0.05 parts by weight, and particularly preferably in the range of 0.001 to 0.03 parts by weight, based on 100 parts by weight of the monomer component, and in this case, the strength characteristics of the produced acrylic rubber bag and the workability of rolls and the like can be highly balanced, and thus are preferable.
The operation after the addition of the reducing agent is not particularly limited, and the polymerization reaction can be terminated after the polymerization reaction is continued for usually 30 minutes or more, preferably 45 minutes or more, more preferably 1 hour or more.
The polymerization conversion rate of the emulsion polymerization is preferably 90% by weight or more, more preferably 95% by weight or more, and in this case, the produced acrylic rubber bag is excellent in strength characteristics and free from monomer odor, and therefore is preferable. At the termination of the polymerization, a polymerization terminator may be used.
After emulsion polymerization, the resulting emulsion polymerization solution (emulsion) is coagulated and dried, and the acrylic rubber can be separated.
(coagulation step)
In the coagulation step after emulsion polymerization, the emulsion polymerization liquid obtained in emulsion polymerization can be coagulated by adding it to the stirred coagulation liquid to produce an aqueous pellet of the acrylic rubber.
The solid content concentration of the emulsion polymerization liquid used in the coagulation reaction is not particularly limited, and is usually adjusted to a range of 5 to 50% by weight, preferably 10 to 45% by weight, and more preferably 20 to 40% by weight.
The coagulant of the coagulant liquid to be used is not particularly limited, and a metal salt is usually used. Examples of the metal salt include: alkali metal, metal salt of group 2 of the periodic table, other metal salt, and the like are preferable, alkali metal salt and metal salt of group 2 of the periodic table are more preferable, metal salt of group 2 of the periodic table is particularly preferable, and magnesium salt is particularly preferable, and in this case, the water resistance, strength characteristics, mold releasability, and workability of the resulting acrylic rubber bag can be highly balanced, and therefore preferable.
Examples of the alkali metal salt include: sodium salts such as sodium chloride, sodium nitrate, and sodium sulfate; potassium salts such as potassium chloride, potassium nitrate, and potassium sulfate; among these, sodium salts are preferable, and sodium chloride and sodium sulfate are particularly preferable.
Examples of the metal salt of group 2 of the periodic table include: magnesium chloride, calcium chloride, magnesium nitrate, calcium nitrate, magnesium sulfate, calcium sulfate, etc., preferably calcium chloride, magnesium sulfate.
Examples of the other metal salts include: zinc chloride, titanium chloride, manganese chloride, iron chloride, cobalt chloride, nickel chloride, aluminum chloride, tin chloride, zinc nitrate, titanium nitrate, manganese nitrate, iron nitrate, cobalt nitrate, nickel nitrate, aluminum nitrate, tin nitrate, zinc sulfate, titanium sulfate, manganese sulfate, iron sulfate, cobalt sulfate, nickel sulfate, aluminum sulfate, tin sulfate, and the like.
These coagulants may be used alone or in combination of two or more, and the amount thereof is usually in the range of 0.01 to 100 parts by weight, preferably in the range of 0.1 to 50 parts by weight, more preferably in the range of 1 to 30 parts by weight, relative to 100 parts by weight of the monomer component. When the coagulant is in this range, the acrylic rubber can be sufficiently coagulated, and the compression set and water resistance in the case of crosslinked acrylic rubber can be highly improved, so that it is preferable.
In the coagulation step of the present invention, it is preferable to concentrate the particle size of the produced aqueous aggregates to a specific region, because the cleaning efficiency and ash removal efficiency during dehydration are remarkably improved. The proportion of the produced aqueous pellet in the range of 710 μm to 6.7mm (6.7 mm excluding 710 μm) is not particularly limited, but is usually 30% by weight or more, preferably 50% by weight or more, more preferably 60% by weight or more, particularly preferably 70% by weight or more, and most preferably 80% by weight or more, based on the total amount of the produced aqueous pellet, and in this case, the water resistance of the acrylic rubber bag can be significantly improved, and is therefore preferred. The proportion of the produced aqueous pellet in the range of 710 μm to 4.75mm (4.75 mm excluding 710 μm) is not particularly limited, but is usually 30% by weight or more, preferably 50% by weight or more, more preferably 60% by weight or more, particularly preferably 70% by weight or more, and most preferably 80% by weight or more, based on the total amount of the produced aqueous pellet, and in this case, the water resistance of the acrylic rubber bag can be significantly improved, and is therefore preferred. Further, the proportion of the produced aqueous pellet in the range of 710 μm to 3.35mm (3.35 mm excluding 710 μm) is not particularly limited, but is usually 20% by weight or more, preferably 30% by weight or more, more preferably 40% by weight or more, particularly preferably 50% by weight or more, and most preferably 60% by weight or more, based on the total amount of the produced aqueous pellet, and in this case, the water resistance of the acrylic rubber bag can be significantly improved, and is therefore preferred.
The method for producing the aqueous aggregates having a particle size within the above range is not particularly limited, and for example, the emulsion polymerization liquid is added to the stirred coagulation liquid (aqueous coagulant solution) or the coagulation agent concentration of the coagulation liquid, the stirring number of the stirred coagulation liquid, and the peripheral speed are specified, whereby the emulsion polymerization liquid is brought into contact with the coagulant.
The coagulant used is usually used as an aqueous solution, and the coagulant concentration of the aqueous solution is usually in the range of 0.1 to 20% by weight, preferably in the range of 0.5 to 15% by weight, more preferably in the range of 1 to 10% by weight, and particularly preferably in the range of 1.5 to 5% by weight, and in this case, the particle size of the produced aqueous aggregates can be uniformly concentrated in a specific region.
The temperature of the coagulating liquid is not particularly limited, but is usually 40℃or higher, preferably 40 to 90℃and more preferably 50 to 80℃and, in this case, uniform aqueous pellets can be produced, which is preferable.
The stirring number (rotation number) of the stirred coagulation liquid, that is, the rotation number of the stirring blade of the stirring device is not particularly limited, and is usually 100rpm or more, preferably 200rpm or more, more preferably 200 to 1000rpm, particularly preferably 300 to 900rpm, and most preferably 400 to 800 rpm.
Since the number of revolutions is such that the particle size of the produced aqueous pellets can be made small and uniform by stirring vigorously to a certain extent, it is preferable that the number of revolutions is not less than the above-mentioned lower limit, the production of aqueous pellets having excessively large particle size and excessively small particle size can be suppressed, and the coagulation reaction can be controlled more easily by setting the number of revolutions to not more than the above-mentioned upper limit.
The peripheral speed of the stirred coagulation liquid, that is, the speed of the outer periphery of the stirring blade of the stirring device is not particularly limited, and the particle size of the resulting aqueous granules can be made small and uniform at a speed of intense stirring to a certain extent, and therefore, is preferably usually 0.5m/s or more, preferably 1m/s or more, more preferably 1.5m/s or more, particularly preferably 2m/s or more, and most preferably 2.5m/s or more. On the other hand, the upper limit of the peripheral speed is not particularly limited, but is usually 50m/s or less, preferably 30m/s or less, more preferably 25m/s or less, and most preferably 20m/s or less, and in this case, the control of the solidification reaction is facilitated, and is therefore preferable.
By setting the above-mentioned conditions of the coagulation reaction (contact method, solid content concentration of emulsion polymerization liquid, concentration and temperature of coagulation liquid, number of revolutions and peripheral speed at the time of stirring of coagulation liquid, etc.) to specific ranges, the shape and pellet size of the produced aqueous pellets are uniform and concentrated, and as a result, the removal of the emulsifier and coagulant at the time of washing and dehydration is remarkably optimized, and as a result, the water resistance and storage stability of the produced acrylic rubber bag can be highly improved, which is preferable.
(cleaning step)
The aqueous pellets produced in the above-described coagulation reaction are preferably washed with hot water before drying.
The washing method is not particularly limited, and can be performed by mixing the produced aqueous pellets with a large amount of hot water.
The amount of hot water to be added for washing is not particularly limited, but is preferably 50 parts by weight or more, preferably 50 to 15000 parts by weight, more preferably 100 to 10000 parts by weight, and even more preferably 500 to 5000 parts by weight per 100 parts by weight of the monomer component, and in this case, the ash content in the acrylic rubber bag can be effectively reduced.
The temperature of the hot water to be used is not particularly limited, but is usually 40 ℃ or higher, preferably 40 to 100 ℃, more preferably 50 to 90 ℃, particularly preferably 60 to 80 ℃, and in this case, the cleaning efficiency can be significantly improved, and thus is most preferred. When the temperature of the hot water to be used is not less than the lower limit, the emulsifier and the coagulant are separated from the aqueous pellet, and the cleaning efficiency is further improved.
The washing time is not particularly limited, but is usually in the range of 1 to 120 minutes, preferably in the range of 2 to 60 minutes, and more preferably in the range of 3 to 30 minutes.
The number of times of washing (water washing) is also not particularly limited, and is usually 1 to 10 times, preferably 1 to 5 times, and more preferably 2 to 3 times. In addition, from the viewpoint of reducing the residual amount of the coagulant in the finally obtained acrylic rubber bag, it is preferable that the number of times of washing is large, but by setting the shape of the aqueous aggregates and the particle size of the aqueous aggregates to a specific range and/or setting the washing temperature to the above-described range, the number of times of washing can be significantly reduced.
(dehydration-drying-Forming Process)
The dehydration-drying-molding step in the method for producing an acrylic rubber bag of the present invention is characterized in that the above-mentioned washed aqueous pellet is dehydrated to a water content of 1 to 40% by weight by using a dehydration cylinder having a dehydration slit, a drying cylinder under reduced pressure and a screw type biaxial extrusion dryer having a die at the tip end, and the dehydrated rubber (sheet-like acrylic rubber) in a sheet form is extruded from the die by drying the dehydrated cylinder to a water content of less than 1% by weight.
In the present invention, the aqueous pellets supplied to the screw type biaxial extrusion dryer are preferably pellets from which free water (water removal) is removed after washing.
(Water removal Process)
In the present invention, in order to improve the dewatering efficiency, it is preferable to provide a dewatering step of separating free water from the washed aqueous pellets by a dewatering machine.
As the water removing machine, a known water removing machine can be used without particular limitation, and examples thereof include: metal mesh, screen mesh, electric screening machine, etc., preferably metal mesh, screen mesh, etc.
The mesh of the dewatering machine is not particularly limited, but is usually in the range of 0.01 to 5mm, preferably in the range of 0.1 to 1mm, more preferably in the range of 0.2 to 0.6mm, and in this case, the loss of the water-containing aggregates is small and the dewatering can be efficiently performed, so that it is preferable.
The water content of the aqueous pellet after the water removal, that is, the water content of the aqueous pellet to be fed to the dehydration-drying step is not particularly limited, but is usually in the range of 50 to 80% by weight, preferably in the range of 50 to 70% by weight, and more preferably in the range of 50 to 60% by weight.
The temperature of the aqueous pellet after the water removal, that is, the temperature of the aqueous pellet to be fed to the dehydration/drying step is not particularly limited, but is usually 40℃or higher, preferably 40 to 100℃or higher, more preferably 50 to 90℃or lower, particularly preferably 55 to 85℃or lower, and most preferably 60 to 80℃or lower, and in this case, the aqueous pellet having a specific heat of up to 1.5 to 2.5 KJ/kg.K, which makes it difficult to raise the temperature, can be dehydrated and dried efficiently by using the screw type biaxial extrusion dryer, which is preferred.
(dehydration of aqueous pellets in the barrel section of the dehydrator)
The dehydration of the aqueous pellets was performed using a dehydration barrel having dehydration slots in a screw type biaxial extrusion dryer. The mesh size of the dewatering slit may be appropriately selected depending on the conditions of use, and is usually in the range of 0.01 to 5mm, preferably in the range of 0.1 to 1mm, more preferably in the range of 0.2 to 0.6mm, and in this case, the loss of the aqueous pellets is small and the dewatering of the aqueous pellets can be efficiently performed, which is preferable.
The number of the dehydration cylinders in the screw type biaxial extrusion dryer is not particularly limited, but is usually plural, preferably 2 to 10, more preferably 3 to 6, and in this case, dehydration of the adhesive acrylic rubber can be efficiently performed, which is preferable.
The removal of water from the hydrous pellets in the dehydration barrel is distinguished by the fact that the water is removed from the dehydration slit in a liquid state (drain) and removed in a vapor state (drain), and in the present invention, drain is defined as dehydration and drain vapor is defined as predrying.
In the dehydration of the hydrous pellets, the water discharged from the dehydration slit may be in either a liquid state (drain) or a vapor state (drain), but in the case of dehydration using a screw type biaxial extrusion dryer having a plurality of dehydration barrels, dehydration of the adhesive acrylic rubber can be performed efficiently by combining drain and drain, so that it is preferable. In a screw type biaxial extrusion dryer having 3 or more dehydration barrels, the dehydration barrel or the steam-discharge dehydration barrel may be appropriately selected according to the purpose of use, and in general, the dehydration barrel is increased when the ash content in the produced acrylic rubber bag is reduced, and the steam-discharge barrel is increased when the water content is reduced.
The setting temperature of the dehydration barrel may be appropriately selected depending on the monomer composition, ash amount, water content, operating conditions and the like of the acrylic rubber, and is usually in the range of 60 to 150 ℃, preferably 70 to 140 ℃, more preferably 80 to 130 ℃. The setting temperature of the dehydration barrel for dehydration in a drained state is usually 60 to 120 ℃, preferably 70 to 110 ℃, more preferably 80 to 100 ℃. The setting temperature of the dehydration cylinder for dehydration in the vapor-exhausted state is usually in the range of 100 to 150 ℃, preferably in the range of 105 to 140 ℃, and more preferably in the range of 110 to 130 ℃.
The water content after the water discharge type dehydration by extruding water from the hydrous pellets is not particularly limited, but is preferably 1 to 40% by weight, more preferably 5 to 40% by weight, still more preferably 5 to 35% by weight, particularly preferably 10 to 35% by weight, and in this case, productivity and ash removal efficiency are highly balanced.
In the case of dehydration of an adhesive acrylic rubber having a reactive group, when the dehydration is performed using a centrifuge or the like, the acrylic rubber adheres to the dehydration slit portion and is hardly dehydrated (the water content is about 45 to 55% by weight), but in the present invention, the water content can be reduced to the above range by using a screw type biaxial extrusion dryer having a dehydration slit and capable of forced extrusion by a screw.
For dehydration of the aqueous pellets in the case of having a drainage type dehydrator cylinder and a steam discharge type dehydrator cylinder, the water content after drainage in the drainage type dehydrator cylinder section is usually 5 to 40% by weight, preferably 10 to 40% by weight, more preferably 15 to 35% by weight, and the water content after pre-drying in the steam discharge type dehydrator cylinder section is usually 1 to 30% by weight, preferably 3 to 20% by weight, more preferably 5 to 15% by weight.
The dehydration time can be shortened by setting the water content after dehydration to the above lower limit or more, deterioration of the acrylic rubber can be suppressed, and the ash content can be sufficiently reduced by setting the water content after dehydration to the above upper limit or less.
(drying of aqueous pellets in the dryer section)
The dehydrated aqueous pellets are preferably dried using a screw type biaxial extrusion dryer having a dryer barrel section, and the drying is performed in the dryer barrel section under reduced pressure. Drying under reduced pressure is preferable because the drying efficiency is improved, and air present in the acrylic rubber is removed, so that an acrylic rubber bag having a high specific gravity and excellent storage stability can be produced. In the present invention, the storage stability can be improved to a high degree by melting the acrylic rubber under reduced pressure and extrusion-drying the same. The storage stability of the acrylic rubber bag is mainly related to the specific gravity of the acrylic rubber bag, and can be controlled by the specific gravity. However, in the case of controlling the storage stability of the acrylic rubber bag having a high specific gravity at a high level, the storage stability of the acrylic rubber bag can be controlled by the degree of vacuum of the extrusion dryer or the like.
The vacuum degree of the dryer cylinder may be appropriately selected, and is usually 1 to 50kPa, preferably 2 to 30kPa, more preferably 3 to 20kPa, and in this case, it is preferable to be able to dry the aqueous pellets efficiently and to remove air from the acrylic rubber, and to be able to significantly improve the storage stability of the acrylic rubber bag.
The setting temperature of the dryer cylinder may be appropriately selected, and is usually in the range of 100 to 250 ℃, preferably in the range of 110 to 200 ℃, more preferably in the range of 120 to 180 ℃, and in this case, the acrylic rubber is preferably dried efficiently without scorching or deterioration, and the amount of methyl ethyl ketone insoluble components in the acrylic rubber bag can be reduced.
The number of the dryer cylinders in the screw type biaxial extrusion dryer is not particularly limited, but is usually plural, preferably 2 to 10, more preferably 3 to 8. The vacuum level in the case of having a plurality of dryer cylinders may be set to be similar to the entire dryer cylinders, or may be changed. In the case of having a plurality of dryer cylinders, the set temperature may be set so that the entire dryer cylinders are at a similar temperature, or the set temperature may be changed, and it is preferable that the temperature of the discharge portion (the side close to the die) is higher than the temperature of the introduction portion (the side close to the dryer cylinder), because the drying efficiency can be improved.
The moisture content of the dried sheet-like dried rubber is usually less than 1% by weight, preferably 0.8% by weight or less, more preferably 0.6% by weight or less. In the present invention, it is particularly preferable to perform melt extrusion after the moisture content of the dried rubber is brought to this value (in a state where water is substantially removed) in a screw type biaxial extrusion dryer, because this can reduce the amount of methyl ethyl ketone insoluble components in the acrylic rubber bag. In the present invention, it is preferable to use a screw type biaxial extruder dryer for melt-kneading or to highly balance the strength characteristics of the acrylic rubber bag and the Banbury processability. In the present invention, "melt-kneading" or "melt-kneading and drying" means: in a screw type biaxial extrusion dryer, the acrylic rubber is kneaded (mixed) in a molten state or extruded in a molten state and dried at this stage; alternatively, the acrylic rubber is kneaded in a molten (plasticized) state by a screw type biaxial extrusion dryer, extruded, and dried.
In the present invention, the shear rate applied to the cylinder of the screw-type biaxial extrusion dryer in a state where the acrylic rubber is substantially free of water is not particularly limited, but is usually 10[ l/s ] or more, preferably 10 to 400[ l/s ], more preferably 50 to 250[ l/s ], and in this case, the storage stability, roll processability, banbury processability, strength characteristics and compression set resistance of the obtained acrylic rubber bag are highly balanced, and therefore preferable.
The shear viscosity of the acrylic rubber in the screw type biaxial extrusion dryer, particularly in the dryer barrel, used in the present invention is not particularly limited, but is usually not more than 12000[ pa·s ], preferably in the range of 1000 to 12000[ pa·s ], more preferably in the range of 2000 to 10000[ pa·s ], particularly preferably in the range of 3000 to 7000[ pa·s ], and most preferably in the range of 4000 to 6000[ pa·s ], and in this case, the storage stability, roll processability, banbury processability and strength characteristics of the obtained acrylic rubber package are highly balanced, and therefore preferable.
(extrusion of dried rubber from die head)
The dried rubber dehydrated and dried by the screw sections of the dehydrator cylinder and the dryer cylinder is conveyed to a screw-free rectifying die section, and extruded into a desired shape from the die section. A perforated plate or a metal mesh may or may not be provided between the screw portion and the die portion.
The die shape is preferably a substantially rectangular shape, and the extruded dry rubber is extruded into a sheet shape, so that a dry rubber having a small air entrainment, a large specific gravity, and excellent storage stability is obtained.
The resin pressure of the die head is not particularly limited, but is usually in the range of 0.1 to 10MPa, preferably in the range of 0.5 to 5MPa, more preferably in the range of 1 to 3MPa, and in this case, the acrylic rubber bag is preferable because of less air entrainment (high specific gravity) and excellent productivity.
Screw type biaxial extrusion dryer and operating conditions
The screw length (L) of the screw type biaxial extrusion dryer to be used may be appropriately selected depending on the purpose of use, and is usually in the range of 3000 to 15000mm, preferably 4000 to 10000mm, and more preferably 4500 to 8000 mm.
The screw diameter (D) of the screw type biaxial extrusion dryer to be used may be appropriately selected depending on the purpose of use, and is usually in the range of 50 to 250mm, preferably in the range of 100 to 200mm, and more preferably in the range of 120 to 160 mm.
The ratio (L/D) of the screw length (L) to the screw diameter (D) of the screw type biaxial extrusion dryer to be used is not particularly limited, but is usually in the range of 10 to 100, preferably 20 to 80, more preferably 30 to 60, and in this case, the dry rubber is preferably not degraded in molecular weight and scorched, and the water content can be reduced to less than 1% by weight.
The number of revolutions (N) of the screw type biaxial extrusion dryer to be used may be appropriately selected depending on the respective conditions, and is usually 10 to 1000rpm, preferably 50 to 750rpm, more preferably 100 to 500rpm, and most preferably 120 to 300rpm, and in this case, the water content of the acrylic rubber bag and the amount of methyl ethyl ketone insoluble components can be efficiently reduced, which is preferable.
The extrusion amount (Q) of the screw type biaxial extrusion dryer to be used is not particularly limited, but is usually in the range of 100 to 1500 kg/hr, preferably 300 to 1200 kg/hr, more preferably 400 to 1000 kg/hr, and most preferably 500 to 800 kg/hr.
The ratio (Q/N) of the extrusion amount (Q) to the rotation number (N) of the screw type biaxial extrusion dryer to be used is not particularly limited, but is usually in the range of 2 to 10, preferably in the range of 3 to 8, more preferably in the range of 4 to 6.
The maximum torque of the screw type biaxial extrusion dryer to be used is not particularly limited, but is usually 30n·m or more, preferably 35n·m or more, and more preferably 40n·m or more. Further, the maximum torque of the screw type biaxial extrusion dryer used in the present invention is usually in the range of 30 to 100n·m, preferably in the range of 35 to 75n·m, more preferably in the range of 40 to 60n·m, and in this case, the roll processability, banbury processability and strength characteristics of the produced acrylic rubber bag can be highly balanced, and thus it is preferable.
The specific energy consumption of the screw type biaxial extrusion dryer to be used is not particularly limited, but is usually 0.1 to 0.25[ kw.h/kg ] or more, preferably 0.13 to 0.23[ kw.h/kg ], and more preferably 0.15 to 0.2[ kw.h/kg ], and in this case, the roll processability, banbury processability and strength characteristics of the obtained acrylic rubber bag are highly balanced, and therefore preferable.
The specific power of the screw type biaxial extrusion dryer to be used is not particularly limited, but is usually 0.2 to 0.6[ A.multidot.h/kg ] or more, preferably 0.25 to 0.55[ A.multidot.h/kg ], more preferably 0.35 to 0.5[ A.multidot.h/kg ], and in this case, the roll processability, banbury processability and strength characteristics of the obtained acrylic rubber bag are highly balanced, and therefore, it is preferable.
The shear rate of the screw type biaxial extrusion dryer used is not particularly limited, but is usually 40 to 150[ l/s ] or more, preferably 45 to 125[ l/s ], more preferably 50 to 100[ l/s ], and the storage stability, roll processability, banbury processability and strength characteristics of the resulting acrylic rubber bag are highly balanced and therefore preferable.
The shear viscosity of the acrylic rubber in the screw type biaxial extrusion dryer to be used is not particularly limited, but is usually 4000 to 8000[ Pa.s ] or less, preferably 4500 to 7500[ Pa.s ], and more preferably 5000 to 7000[ Pa.s ], and in this case, the storage stability, roll processability, banbury processability and strength characteristics of the obtained acrylic rubber bag are highly balanced, and therefore preferable.
In this way, in the present invention, it is preferable to use an extrusion dryer having a twin screw, because dehydration, drying, and molding under high shear conditions can be performed.
(sheet-like Dry rubber)
The shape of the dried rubber extruded from the screw type biaxial extrusion dryer is preferably a sheet shape, since the specific gravity can be increased without involving air, and the storage stability can be improved to a high degree. The sheet-like dry rubber extruded from the screw type biaxial extrusion dryer is generally cooled and cut to be used as a sheet-like acrylic rubber.
The thickness of the sheet-like dry rubber extruded from the screw type biaxial extrusion dryer is not particularly limited, but is usually in the range of 1 to 40mm, preferably in the range of 2 to 35mm, more preferably in the range of 3 to 30mm, most preferably in the range of 5 to 25mm, and in this case, the handling property and productivity are excellent, and therefore, it is preferable. In particular, since the thermal conductivity of the sheet-like dry rubber is as low as 0.15 to 0.35W/mK, the thickness of the sheet-like dry rubber is usually in the range of 1 to 30mm, preferably in the range of 2 to 25mm, more preferably in the range of 3 to 15mm, and particularly preferably in the range of 4 to 12mm, in the case of improving the cooling efficiency and remarkably improving the productivity.
The width of the sheet-like dry rubber extruded from the screw type biaxial extrusion dryer may be appropriately selected depending on the purpose of use, and is usually in the range of 300 to 1200mm, preferably 400 to 1000mm, more preferably 500 to 800 mm.
The temperature of the dried rubber extruded from the screw type biaxial extrusion dryer is not particularly limited, but is usually in the range of 100 to 200 ℃, preferably in the range of 110 to 180 ℃, and more preferably in the range of 120 to 160 ℃.
The water content of the dried rubber extruded from the screw type biaxial extrusion dryer is not particularly limited, but is usually less than 1% by weight, preferably 0.8% by weight or less, more preferably 0.6% by weight or less.
The sheet-like dry rubber extruded from the screw type biaxial extrusion dryer is not particularly limited in the complex viscosity ([ eta ]100 ℃) at 100℃and is usually in the range of 1500 to 6000[ Pa.s ], preferably in the range of 2000 to 5000[ Pa.s ], more preferably in the range of 2500 to 4000[ Pa.s ], and most preferably in the range of 2500 to 3500[ Pa.s ], and in this case, the extrudability and shape retention as a sheet are highly balanced and therefore preferred. That is, the extrusion properties can be further improved by the lower limit or more, and the collapse and fracture of the shape of the sheet-like dry rubber can be suppressed by the upper limit or less.
The sheet-like dry rubber extruded from the screw type biaxial extrusion dryer can be folded directly and used, and can be usually cut and used.
The sheet-like dry rubber is not particularly limited, and since the acrylic rubber of the present invention has strong adhesiveness, it is preferable to cool the sheet-like dry rubber and then cut the sheet-like dry rubber in order to continuously cut the sheet-like dry rubber without involving air.
The cutting temperature of the sheet-like dry rubber is not particularly limited, but is usually 60℃or lower, preferably 55℃or lower, more preferably 50℃or lower, and in this case, the cutting property and productivity are highly balanced, and therefore, it is preferable.
The sheet-like dry rubber is not particularly limited, and is preferably cut continuously without involving air, because the sheet-like dry rubber has a complex viscosity ([ eta ]60 ℃) of usually 15000 or less, preferably 2000 to 10000[ Pa.s ], more preferably 2500 to 7000[ Pa.s ], and most preferably 2700 to 5500[ Pa.s ].
The ratio of the complex viscosity ([ eta ]100 ℃) at 100℃to the complex viscosity ([ eta ]60 ℃) at 60℃ ([ eta ]100 ℃/[ eta ]60 ℃) of the sheet-like dry rubber is not particularly limited, and is appropriately selected depending on the purpose of use, but is usually 0.5 or more, preferably 0.6 or more, more preferably 0.7 or more, particularly preferably 0.8 or more, most preferably 0.85 or more, and the upper limit is usually 0.98 or less, preferably 0.97 or less, more preferably 0.96 or less, particularly preferably 0.95 or less, most preferably 0.93 or less, and in this case, air inclusion is small, and the cutting property and productivity are highly balanced, and therefore, it is preferable.
The method for cooling the sheet-like dry rubber is not particularly limited, and the sheet-like dry rubber may be left at room temperature, and since the thermal conductivity of the sheet-like dry rubber is extremely small, the sheet-like dry rubber is preferably 0.15 to 0.35W/mK, and forced cooling by air cooling with air blowing or cooling, a water spraying method, a dipping method in water, or the like is preferable, and the air cooling method with air blowing or cooling is particularly preferable.
In the air cooling system of the sheet-like dry rubber, for example, the sheet-like dry rubber can be extruded from a screw extruder onto a conveyor such as a conveyor belt, and conveyed and cooled while blowing cool air. The temperature of the cold air is not particularly limited, and is usually in the range of 0 to 25 ℃, preferably in the range of 5 to 25 ℃, and more preferably in the range of 10 to 20 ℃. The length of cooling is not particularly limited, and is usually in the range of 5 to 500m, preferably in the range of 10 to 200m, and more preferably in the range of 20 to 100 m. The cooling rate of the sheet-like dry rubber is not particularly limited, but is usually 40℃per hour or more, preferably 50℃per hour or more, more preferably 100℃per hour or more, and particularly preferably 150℃per hour or more, and in this case, the cutting is easy, air is not involved in the molded article, and the storage stability is good, which is preferable. In the present invention, the cooling rate of the sheet-like dry rubber is usually 40℃per hour or more, preferably 50℃per hour or more, more preferably 100℃per hour or more, and particularly preferably 150℃per hour or more, and in this case, the scorch stability when the acrylic rubber is coated into a rubber composition is particularly excellent, and therefore, it is preferable.
The cutting length of the sheet-like dry rubber is not particularly limited, and may be appropriately selected depending on the purpose of use, and is usually in the range of 100 to 800mm, preferably in the range of 200 to 500mm, and more preferably in the range of 250 to 450 mm.
The sheet-like acrylic rubber thus obtained is excellent in handling properties, roll processability, crosslinking properties, strength properties and compression set resistance, and also excellent in storage stability, banbury processability and water resistance, as compared with the pellet-like acrylic rubber, and can be used as it is or after lamination and encapsulation.
(lamination step)
The lamination step of the present invention is characterized by laminating the cut sheet-like dry rubber and rubber-wrapping.
The lamination temperature of the sheet-like dry rubber is not particularly limited, but is usually 30℃or higher, preferably 35℃or higher, more preferably 40℃or higher, and in this case, air involved in lamination can be released, which is preferable. The number of laminated sheets may be appropriately selected according to the size or weight of the above-mentioned rubber-coated acrylic rubber. The rubber-covered acrylic rubber of the present invention is integrated by the self weight of the laminated sheet-like dry rubber.
The acrylic rubber bag of the present invention thus obtained is superior to the pellet-like acrylic rubber in handling property, and is excellent in roll processability, banbury processability, crosslinkability, water resistance, storage stability, strength characteristics and compression set resistance, and can be used as it is or after being cut into a desired amount, put into a mixer such as a banbury mixer or a roll, and used.
< rubber composition >
The rubber composition of the present invention is characterized by comprising a rubber component containing the acrylic rubber bag, a filler and a crosslinking agent.
The acrylic rubber bag of the present invention may be used alone as the rubber component which is the main component of the rubber composition of the present invention, or may be used in combination with other rubber components as required. The content of the acrylic rubber composition of the present invention in the rubber component may be appropriately selected depending on the purpose of use, and is, for example, usually 30% by weight or more, preferably 50% by weight or more, and more preferably 70% by weight or more.
The other rubber component to be combined with the acrylic rubber bag of the present invention is not particularly limited, and examples thereof include natural rubber, polybutadiene rubber, polyisoprene rubber, styrene-butadiene rubber, acrylonitrile-butadiene rubber, silicone rubber, fluororubber, olefin elastomer, styrene elastomer, vinyl chloride elastomer, polyester elastomer, polyamide elastomer, polyurethane elastomer, polysiloxane elastomer, and the like.
These other rubber components can be used singly or in combination of two or more. The shape of the other rubber component may be any of a pellet, strand, bale, sheet, powder, and the like. The content of the other rubber component in the whole rubber component may be appropriately selected within a range that does not impair the effect of the present invention, and is, for example, generally 70% by weight or less, preferably 50% by weight or less, more preferably 30% by weight or less.
The filler contained in the rubber composition is not particularly limited, and examples thereof include: the reinforcing filler, the non-reinforcing filler, and the like are preferable since the reinforcing filler is excellent in roll processability, banbury processability, and crosslinking property in a short time, and the crosslinked product is highly excellent in water resistance, strength characteristics, and compression set resistance.
Examples of the reinforcing filler include: carbon blacks such as furnace black, acetylene black, thermal black, channel black, and graphite; and silica such as wet silica, dry silica and colloidal silica. Examples of the non-reinforcing filler include quartz powder, diatomaceous earth, zinc oxide, basic magnesium carbonate, activated calcium carbonate, magnesium silicate, aluminum silicate, titanium dioxide, talc, aluminum sulfate, calcium sulfate, and barium sulfate.
These fillers may be used alone or in combination of two or more, and the amount thereof may be appropriately selected within a range that does not impair the effects of the present invention, and is usually in a range of 1 to 200 parts by weight, preferably in a range of 10 to 150 parts by weight, more preferably in a range of 20 to 100 parts by weight, relative to 100 parts by weight of the rubber component.
The crosslinking agent used in the rubber composition is not particularly limited, and conventionally known crosslinking agents may be selected according to the purpose of use, and examples thereof include: inorganic crosslinking agents such as sulfur compounds, organic crosslinking agents, and the like, and organic crosslinking agents are preferable. As the crosslinking agent, either a polyvalent compound or a monovalent compound may be used, and a polyvalent compound having 2 or more reactive groups is preferable. Further, as the crosslinking agent, either an ion-crosslinkable compound or a radical-crosslinkable compound can be used, and an ion-crosslinkable compound is preferable.
The organic crosslinking agent is not particularly limited, but is preferably an ion-crosslinkable organic compound, and particularly preferably a polyion organic compound. When the crosslinking agent is a polyion organic compound (polyion crosslinkable compound), the rubber composition is particularly preferable because it is excellent in roll processability, banbury processability and crosslinking property in a short period of time, and the crosslinked product is highly excellent in water resistance, strength characteristics and compression set resistance. The "ion" of the ion-crosslinkable or multi-element ion is an ion reactive ion, and is not particularly limited as long as it is an ion that reacts with an ion reactive group of the ion reactive group-containing monomer of the above-mentioned acrylic rubber, and examples thereof include ion-crosslinkable organic compounds having an ion reactive group such as an amine group, an epoxy group, a carboxyl group, and a thiol group.
Specific examples of the polyionic organic compound include: the polyamine compound, the polyepoxide compound, the polycarboxylic acid compound, the polythiol compound, and the like are preferably a polyamine compound and a polythiol compound, and more preferably a polyamine compound.
Examples of the polyamine compound include: aliphatic polyamine compounds such as hexamethylenediamine, hexamethylenediamine carbamate, N' -biscinnamaldehyde-1, 6-hexamethylenediamine; 4,4 '-methylenedianiline, p-phenylenediamine, m-phenylenediamine, 4' -diaminodiphenyl ether, 3,4 '-diaminodiphenyl ether, 4' - (m-phenylenediisopropylene) diphenylamine, 4'- (p-phenylenediisopropylene) diphenylamine aromatic polyamine compounds such as 2,2' -bis [4- (4-aminophenoxy) phenyl ] propane, 4 '-diaminobenzanilide, 4' -bis (4-aminophenoxy) biphenyl, m-xylylenediamine, p-xylylenediamine, and 1,3, 5-benzenetriamine. Among these, hexamethylenediamine carbamate, 2' -bis [4- (4-aminophenoxy) phenyl ] propane, and the like are preferable. Further, as the polyamine compound, carbonates thereof can be preferably used. These polyamine compounds are particularly preferably used in combination with a carboxyl group-containing acrylic rubber bag or an epoxy group-containing acrylic rubber bag.
As the polythiol compound, a triazine thiol compound is preferably used, and examples thereof include: 6-trimercapto-s-triazine, 2-anilino-4, 6-dithiol-s-triazine, 1-dibutylamino-3, 5-dimercaptotriazine, 2-dibutylamino-4, 6-dithiol-s-triazine, 1-phenylamino-3, 5-dimercaptotriazine, 2,4, 6-trimercapto-1, 3, 5-triazine, 1-hexylamino-3, 5-dimercaptotriazine, and the like. These triazine thiol compounds are particularly preferably used in combination with an acrylic rubber bag containing chlorine atoms.
As the other polyvalent organic compound, there may be mentioned: and polycarboxylic acid compounds such as tetradecanedioic acid, metal dithiocarbamates such as zinc dimethyldithiocarbamate. These other polyvalent organic compounds are particularly preferably used in combination with an epoxy group-containing acrylic rubber bag.
These crosslinking agents may be used alone or in combination of two or more, and the amount thereof is usually 0.001 to 20 parts by weight, preferably 0.1 to 10 parts by weight, more preferably 0.1 to 5 parts by weight, relative to 100 parts by weight of the rubber component. When the amount of the crosslinking agent is in this range, the rubber elasticity can be made sufficient, and the mechanical strength as a crosslinked rubber product can be made excellent, which is preferable.
The rubber composition of the present invention may contain an antioxidant as needed. The type of the antioxidant is not particularly limited, and examples thereof include: other phenol-based antioxidants such as 2, 6-di-tert-butyl-4-methylphenol, 2, 6-di-tert-butylphenol, butylhydroxyanisole, 2, 6-di-tert-butyl- α -dimethylamino-p-cresol, octadecyl-3- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionate, styrenated phenol, 2' -methylenebis (6- α -methyl-benzyl-p-cresol), 4' -methylenebis (2, 6-di-tert-butylphenol), 2' -methylenebis (4-methyl-6-tert-butylphenol), 2, 4-bis [ (octylthio) methyl ] -6-methylphenol, 2' -thiobis (4-methyl-6-tert-butylphenol), 4' -thiobis (6-tert-butylphenol), 2, 6-di-tert-butyl-4- [4, 6-bis (octylthio) -1,3, 5-triazin-2-ylamino ] phenol; phosphite antioxidants such as tris (nonylphenyl) phosphite, diphenylisodecyl phosphite, tetraphenyl dipropylene glycol bisphosphite, etc.; thioester-based antioxidants such as dilauryl thiodipropionate; amine-based antioxidants such as phenyl- α -naphthylamine, phenyl- β -naphthylamine, p- (p-toluenesulfonamide) -diphenylamine, 4'- (α, α -dimethylbenzyl) diphenylamine, N-diphenyl-p-phenylenediamine, N-isopropyl-N' -phenyl-p-phenylenediamine, butyraldehyde-aniline condensate, and the like; imidazole-based antioxidants such as 2-mercaptobenzimidazole; quinoline antioxidants such as 6-ethoxy-2, 4-trimethyl-1, 2-dihydroquinoline; hydroquinone-based antioxidants such as 2, 5-di-t-amyl hydroquinone; etc. Among these, amine-based antioxidants are particularly preferable.
These antioxidants may be used alone or in combination of two or more, and the blending amount thereof is usually in the range of 0.01 to 15 parts by weight, preferably in the range of 0.1 to 10 parts by weight, more preferably in the range of 1 to 5 parts by weight, relative to 100 parts by weight of the rubber component.
The rubber composition of the present invention contains the rubber component, filler and crosslinking agent of the acrylic rubber bag of the present invention as essential components, and optionally contains an antioxidant as required, and optionally contains other additives commonly used in the art, for example: crosslinking aids, crosslinking accelerators, crosslinking retarders, silane coupling agents, plasticizers, processing aids, lubricating materials, pigments, colorants, antistatic agents, foaming agents, and the like. These other compounding agents may be used alone or in combination of two or more kinds, and the compounding amounts thereof may be appropriately selected within a range that does not impair the effects of the present invention.
The method for producing the rubber composition of the present invention includes a method of mixing the rubber component containing the acrylic rubber bag of the present invention, the filler, the crosslinking agent, and optionally the antioxidant and other compounding agents, and any method used in the conventional rubber processing field can be used at the time of mixing, for example, an open roll mill, a Banbury mixer, various kneaders, and the like. The mixing step of the components may be carried out in accordance with a usual procedure carried out in the rubber processing field, and it is preferable that, for example, after sufficiently mixing components which are not easily reacted or decomposed by heat, a crosslinking agent or the like which is a component which is easily reacted or decomposed by heat is mixed at a temperature at which no reaction or decomposition occurs in a short period of time.
< crosslinked rubber >
The rubber crosslinked product of the present invention is obtained by crosslinking the rubber composition.
The rubber crosslinked product of the present invention can be produced by the following method: the rubber composition of the present invention is molded by a molding machine, such as an extruder, an injection molding machine, a compressor, or a roll, which corresponds to a desired shape, and is subjected to a crosslinking reaction by heating to fix the shape, thereby producing a rubber crosslinked product. In this case, the crosslinking may be performed after the preliminary molding, or may be performed at the same time as the molding. The molding temperature is usually 10 to 200℃and preferably 25 to 150 ℃. The crosslinking temperature is usually 100 to 250 ℃, preferably 130 to 220 ℃, more preferably 150 to 200 ℃, and the crosslinking time is usually 0.1 minutes to 10 hours, preferably 1 minute to 5 hours. As the heating method, a method for crosslinking the rubber such as pressing heating, steam heating, oven heating, and hot air heating may be appropriately selected.
The rubber crosslinked product of the present invention may be subjected to secondary crosslinking by further heating according to the shape, size, etc. of the rubber crosslinked product. The secondary crosslinking varies depending on the heating method, crosslinking temperature, shape, etc., and is preferably carried out for 1 to 48 hours. The heating method and the heating temperature are properly selected.
The rubber crosslinked product of the present invention maintains tensile strength, elongation, hardness, etc. as basic properties of rubber, and has excellent compression set resistance and water resistance.
The rubber crosslinked material of the present invention can be preferably used as, for example, by making full use of the above-mentioned characteristics: sealing materials such as O-rings, sealing materials, diaphragms, oil seals, shaft seals, bearing seals, mechanical seals, wellhead seals, seals for electrical/electronic devices, and seals for air compression devices; a rocker cover gasket attached to a connection portion between the cylinder block and the cylinder, an oil pan gasket attached to a connection portion between the oil pan and the cylinder head or the transmission case, a gasket for a fuel cell spacer attached between a pair of cases sandwiching a unit cell having a positive electrode, an electrolyte plate, and a negative electrode, a gasket for a top cover of a hard disk drive, and the like; a buffer material and a vibration-proof material; a wire coating material; industrial belts; tubes/hoses; sheets, and the like.
Furthermore, the rubber crosslinked product of the present invention is preferably used as an extrusion molded product and a die crosslinked product for automobile use, for example: fuel-oil hoses such as fuel tanks including fuel hoses, filler neck hoses, exhaust hoses, paper hoses, and oil hoses; a turbo charge air hose: an air hose such as a transmission control hose; various hoses such as radiator hoses, heater hoses, brake hoses, air conditioner hoses, and the like.
< Structure of apparatus for manufacturing acrylic rubber bag >
Next, a structure of an apparatus for manufacturing an acrylic rubber bag according to an embodiment of the present invention will be described. Fig. 1 is a diagram schematically showing an example of an acrylic rubber manufacturing system having an apparatus structure for manufacturing an acrylic rubber bag according to an embodiment of the present invention. In the production of the acrylic rubber bag of the present invention, for example, an acrylic rubber production system 1 shown in fig. 1 can be used.
The acrylic rubber production system 1 shown in fig. 1 is composed of an emulsion polymerization reactor, a coagulation device 3, a cleaning device 4, a water remover 43, and a screw type biaxial extrusion dryer, which are not shown.
The emulsion polymerization reactor is configured to perform the above-described treatment in the emulsion polymerization step. The emulsion polymerization reactor not shown in fig. 1 has, for example: a polymerization reaction tank, a temperature control part for controlling the reaction temperature, and a stirring device with a motor and stirring blades. In the emulsion polymerization reactor, water and an emulsifier are mixed with a monomer component for forming an acrylic rubber, and the mixture is emulsified while being properly stirred by a stirrer, and an emulsion polymerization reaction is initiated in the presence of a redox catalyst comprising an inorganic radical generator and a reducing agent, and a chain transfer agent is added after the batch during the polymerization, whereby an emulsion polymerization liquid can be obtained. The emulsion polymerization reactor may be any of a batch type, a semi-batch type and a continuous type, or may be any of a tank type reactor and a tube type reactor.
The coagulation apparatus 3 shown in fig. 1 is configured to perform the treatment in the coagulation step. As schematically illustrated in fig. 1, the solidification apparatus 3 includes, for example, a stirring tank 30, a heating unit 31 for heating the inside of the stirring tank 30, a temperature control unit not shown for controlling the temperature in the stirring tank 30, a stirring device 34 including a motor 32 and stirring blades 33, and a drive control unit not shown for controlling the rotation number and rotation speed of the stirring blades 33. In the coagulation apparatus 3, the emulsion polymerization liquid obtained in the emulsion polymerization reactor is brought into contact with a coagulation liquid to coagulate the emulsion polymerization liquid, whereby an aqueous pellet can be produced.
In the coagulation device 3, for example, the emulsion polymerization liquid may be brought into contact with the coagulation liquid by adding the emulsion polymerization liquid to the stirred coagulation liquid. That is, the agitation tank 30 of the coagulation device 3 is filled with a coagulation liquid in advance, and an emulsion polymerization liquid is added to the coagulation liquid and brought into contact therewith to coagulate the emulsion polymerization liquid, thereby producing an aqueous pellet.
The heating unit 31 of the solidifying apparatus 3 is configured to heat the solidifying liquid filled in the stirring tank 30. The temperature control unit of the solidification apparatus 3 is configured to control the temperature in the stirring tank 30 by controlling the heating operation of the heating unit 31 while monitoring the temperature in the stirring tank 30 measured by the thermometer. The temperature of the solidification liquid in the stirring tank 30 is controlled to be normally 40 ℃ or higher, preferably 40 to 90 ℃, and more preferably 50 to 80 ℃ by the temperature control unit.
The stirring device 34 of the solidifying apparatus 3 is configured to stir the solidification liquid filled in the stirring tank 30. Specifically, the stirring device 34 has a motor 32 that generates rotational energy consumption and a stirring blade 33 that extends in a vertical direction with respect to a rotation axis of the motor 32. The stirring blade 33 can rotate around a rotation axis by the rotation energy of the motor 32 in the coagulation liquid filled in the stirring tank 30, and thereby the coagulation liquid can flow. The shape, size, number of the stirring vanes 33, and the like are not particularly limited.
The drive control unit of the coagulation device 3 is configured to control the rotational drive of the motor 32 of the stirring device 34, and to set the rotation number and rotation speed of the stirring blade 33 of the stirring device 34 to predetermined values. The rotation of the stirring blade 33 is controlled by the drive control unit so that the stirring number of the solidification liquid is, for example, in a range of usually 100rpm or more, preferably 200 to 1000rpm, more preferably 300 to 900rpm, and particularly preferably 400 to 800 rpm. The rotation of the stirring blade 33 is controlled by the drive control unit so that the peripheral speed of the solidification liquid is usually 0.5m/s or more, preferably 1m/s or more, more preferably 1.5m/s or more, particularly preferably 2m/s or more, and most preferably 2.5m/s or more. Further, the rotation of the stirring blade 33 is controlled by the drive control unit so that the upper limit value of the peripheral speed of the solidification liquid is usually 50m/s or less, preferably 30m/s or less, more preferably 25m/s or less, and most preferably 20m/s or less.
The cleaning apparatus 4 shown in fig. 1 is configured to perform the processing in the above-described cleaning process. As schematically illustrated in fig. 1, the cleaning apparatus 4 includes, for example, a cleaning tank 40, a heating unit 41 for heating the cleaning tank 40, and a temperature control unit, not illustrated, for controlling the temperature in the cleaning tank 40. In the cleaning device 4, the aqueous pellets produced in the coagulation device 3 are mixed with a large amount of water and cleaned, whereby the ash content in the finally obtained acrylic rubber bag can be effectively reduced.
The heating unit 41 of the cleaning device 4 is configured to heat the inside of the cleaning tank 40. The temperature control unit of the cleaning apparatus 4 is configured to control the temperature in the cleaning tank 40 by controlling the heating operation of the heating unit 41 while monitoring the temperature in the cleaning tank 40 measured by the thermometer. As described above, the temperature of the washing water in the washing tub 40 is controlled to be normally 40 ℃ or higher, preferably 40 to 100 ℃, more preferably 50 to 90 ℃, and most preferably 60 to 80 ℃.
The aqueous pellets washed by the washing apparatus 4 are supplied to a screw type biaxial extrusion dryer 5 for performing a dehydration step and a drying step. In this case, the washed aqueous pellets are preferably fed to the screw type biaxial extrusion dryer 5 after passing through the water separator 43 capable of separating free water. The water removing machine 43 may be, for example, a metal mesh, a screen, an electric sieving machine, or the like.
When the washed aqueous pellets are fed to the screw type biaxial extrusion dryer 5, the temperature of the aqueous pellets is preferably 40 ℃ or higher, more preferably 60 ℃ or higher. For example, the temperature of the water used for washing in the washing device 4 may be set to 60 ℃ or higher (for example, 70 ℃) so that the temperature of the aqueous pellets at the time of being supplied to the screw type biaxial extrusion dryer 5 can be maintained to 60 ℃ or higher, or may be heated so that the temperature of the aqueous pellets is 40 ℃ or higher, preferably 60 ℃ or higher at the time of being transported from the washing device 4 to the screw type biaxial extrusion dryer 5. This can effectively perform the dehydration step and the drying step as subsequent steps, and can greatly reduce the water content of the finally obtained dried rubber.
The screw type biaxial extrusion dryer 5 shown in fig. 1 is configured to perform the above-described dehydration step and drying step. In fig. 1, a screw type biaxial extrusion dryer 5 is shown as a preferable example, but a centrifugal separator, a squeezer, or the like may be used as a dehydrator for performing the treatment in the dehydration step, or a hot air dryer, a reduced pressure dryer, an expansion dryer, a kneader type dryer, or the like may be used as a dryer for performing the treatment in the drying step.
The screw type biaxial extrusion dryer 5 is configured to mold the dried rubber obtained through the dehydration step and the drying step into a predetermined shape and discharge the molded rubber. Specifically, the screw type biaxial extrusion dryer 5 is configured as follows: a dewatering machine cylinder 53 having a function as a dewatering machine for dewatering the aqueous pellets washed by the washing device 4; and a dryer barrel section 54 having a function as a dryer for drying the aqueous pellets; also provided is a die 59 having a molding function for molding the aqueous pellets on the downstream side of the screw type biaxial extrusion dryer 5.
The structure of the screw type biaxial extrusion dryer 5 will be described below with reference to fig. 2. Fig. 2 shows a structure of a preferable embodiment of the screw type biaxial extrusion dryer 5 shown in fig. 1. The above-described dehydration-drying step can be preferably performed by the screw type biaxial extrusion dryer 5.
The screw type biaxial extrusion dryer 5 shown in fig. 2 is a biaxial screw type extrusion dryer having a pair of screws not shown in the cylinder unit 51. The screw type biaxial extrusion dryer 5 has a drive unit 50 that rotationally drives a pair of screws in a barrel unit 51. With this structure, the acrylic rubber can be dried by applying high shear, which is preferable. The drive unit 50 is mounted at the upstream end (left end in fig. 2) of the barrel unit 51. Further, the screw type biaxial extrusion dryer 5 has a die 59 at the downstream end (right end in fig. 2) of the barrel unit 51.
From the upstream side to the downstream side (from the left side to the right side in fig. 2), the barrel unit 51 has a supply barrel portion 52, a dehydration barrel portion 53, and a dryer barrel portion 54.
The supply cylinder portion 52 is composed of 2 supply cylinders, i.e., a 1 st supply cylinder 52a and a 2 nd supply cylinder 52 b.
The dewatering cylinder section 53 is composed of 3 dewatering cylinders, namely, a 1 st dewatering cylinder 53a, a 2 nd dewatering cylinder 53b, and a 3 rd dewatering cylinder 53 c.
The dryer section 54 is composed of 8 dryer cylinders, i.e., a 1 st dryer cylinder 54a, a 2 nd dryer cylinder 54b, a 3 rd dryer cylinder 54c, a 4 th dryer cylinder 54d, a 5 th dryer cylinder 54e, a 6 th dryer cylinder 54f, a 7 th dryer cylinder 54g, and an 8 th dryer cylinder 54 h.
As described above, the barrel unit 51 is constituted by connecting 13 divided barrels 52a to 52b, 53a to 53c, 54a to 54h from the upstream side to the downstream side.
The screw type biaxial extrusion dryer 5 further includes heating means, not shown, for heating the respective cylinders 52a to 52b, 53a to 53c, 54a to 54h individually, and for heating the aqueous pellets in the respective cylinders 52a to 52b, 53a to 53c, 54a to 54h individually to a predetermined temperature. The heating units have numbers corresponding to the respective barrels 52a to 52b, 53a to 53c, 54a to 54 h. As such heating means, for example, a structure in which high-temperature steam or the like is supplied from the steam supply means in a steam flow shield formed in each of the barrels 52a to 52b, 53a to 53c, 54a to 54h can be used, but the invention is not limited thereto. The screw type biaxial extrusion dryer 5 further includes a temperature control unit, not shown, for controlling the set temperatures of the heating units corresponding to the respective cylinders 52a to 52b, 53a to 53c, and 54a to 54 h.
The number of supply cylinders, dewatering cylinders, and drying cylinders constituting the respective cylinder sections 52, 53, and 54 in the cylinder unit 51 is not limited to the one shown in fig. 2, and may be set to a number corresponding to the water content of the aqueous pellets of the acrylic rubber to be dried.
For example, the number of supply barrels to the barrel portion 52 may be, for example, 1 to 3. The number of the dewatering cylinders of the dewatering cylinder section 53 is preferably 2 to 10, for example, and in the case of 3 to 6, it is more preferable because the dewatering of the water-containing aggregates of the adhesive acrylic rubber can be efficiently performed. The number of the dryer cylinders of the dryer cylinder section 54 is preferably 2 to 10, more preferably 3 to 8, for example.
The pair of screws in the barrel unit 51 are rotationally driven by a driving unit such as a motor housed in the driving unit 50. The pair of screws extend from the upstream side to the downstream side in the barrel unit 51, and by the rotation driving, the aqueous pellets supplied to the supply barrel unit 52 can be conveyed to the downstream side while being mixed. The pair of screws are preferably biaxial meshing type in which the flight portion and the groove portion are in meshing engagement, whereby the dewatering efficiency and drying efficiency of the aqueous pellet can be improved.
The rotation direction of the pair of screws may be the same direction or different directions, and from the viewpoint of self-cleaning performance, the pair of screws are preferably rotated in the same direction. The screw shape of the pair of screws is not particularly limited as long as it is a shape required in each of the cylinder portions 52, 53, 54.
The supply cylinder section 52 is a region in which the aqueous pellets are supplied into the cylinder unit 51. The 1 st supply cylinder 52a of the supply cylinder section 52 has a feed port 55 for supplying the aqueous pellets into the cylinder unit 51.
The dewatering cylinder 53 is a region in which a liquid (slurry) water containing a coagulant or the like is separated from the aqueous pellet and discharged.
The 1 st to 3 rd dewatering cylinders 53a to 53c constituting the dewatering cylinder 53 have dewatering slits 56a, 56b, 56c for discharging the water of the aqueous pellets to the outside, respectively. A plurality of dewatering slits 56a, 56b, 56c are formed in each dewatering cylinder 53a to 53 c.
The slit width, that is, the mesh width of each dewatering slit 56a, 56b, 56c may be appropriately selected depending on the conditions of use, and is usually 0.01 to 5mm, preferably 0.1 to 1mm, more preferably 0.2 to 0.6mm, from the viewpoint that the loss of the aqueous pellets is small and the dewatering of the aqueous pellets can be efficiently performed.
The removal of water from the hydrous pellets in each of the dewatering cylinders 53a to 53c of the dewatering cylinder 53 is both in the case of removing water in a liquid state from each of the dewatering slits 56a, 56b, 56c and in the case of removing water in a vapor state. In the dehydrator cylinder 53 of the present embodiment, the case of removing water in a liquid state is defined as drain, and the case of removing water in a vapor state is defined as drain.
The combination of water discharge and steam discharge in the dehydrator cylinder 53 is preferable because the water content of the adhesive acrylic rubber can be reduced efficiently. In the dewatering cylinder section 53, which of the 1 st to 3 rd dewatering cylinders 53a to 53c is used for dewatering or discharging steam is appropriately set according to the purpose of use, and in general, in the case of reducing the ash content in the produced acrylic rubber, the dewatering cylinder for dewatering can be increased. In this case, for example, as shown in fig. 2, the 1 st and 2 nd dewatering cylinders 53a and 53b on the upstream side are used for water discharge, and the 3 rd dewatering cylinder 53c on the downstream side is used for steam discharge. For example, in the case where the dewatering cylinder portion 53 has 4 dewatering cylinders, a mode in which water is discharged from the 3 dewatering cylinders on the upstream side and steam is discharged from the 1 dewatering cylinder on the downstream side can be considered. On the other hand, in the case of decreasing the water content, a dehydration cylinder in which steam discharge is performed may be increased.
As described in the above dehydration-drying step, the setting temperature of the dehydration barrel section 53 is usually in the range of 60 to 150 ℃, preferably in the range of 70 to 140 ℃, more preferably in the range of 80 to 130 ℃, the setting temperature of the dehydration barrel that performs dehydration in a water discharge state is usually in the range of 60 to 120 ℃, preferably in the range of 70 to 110 ℃, more preferably in the range of 80 to 100 ℃, and the setting temperature of the dehydration barrel that performs dehydration in a steam discharge state is usually in the range of 100 to 150 ℃, preferably in the range of 105 to 140 ℃, more preferably in the range of 110 to 130 ℃.
The dryer cylinder 54 is a region in which the dehydrated aqueous pellets are dried under reduced pressure. The 2 nd, 4 th, 6 th, and 8 th dryer barrels 54b, 54d, 54f, and 54h constituting the dryer barrel section 54 have exhaust ports 58a, 58b, 58c, 58d for degassing, respectively. Exhaust pipes, not shown, are connected to the exhaust ports 58a, 58b, 58c, 58d, respectively.
A vacuum pump, not shown, is connected to the end of each exhaust pipe, and the interior of the dryer cylinder 54 is depressurized to a predetermined pressure by the operation of these vacuum pumps. The screw extruder 5 has a pressure control unit, not shown, for controlling the operation of these vacuum pumps to control the vacuum degree in the dryer barrel 54.
The vacuum degree in the dryer cylinder 54 may be appropriately selected, and is set to be generally 1 to 50kPa, preferably 2 to 30kPa, and more preferably 3 to 20kPa, as described above.
The temperature to be set in the dryer barrel 54 may be appropriately selected, and is usually set to 100 to 250 ℃, preferably 110 to 200 ℃, and more preferably 120 to 180 ℃ as described above.
In each of the dryer cylinders 54a to 54h constituting the dryer cylinder section 54, the set temperature in all of the dryer cylinders 54a to 54h may be set to a similar value, or may be different, and it is preferable that the drying efficiency is improved when the temperature on the downstream side (the die 59 side) is set to be higher than the temperature on the upstream side (the dryer cylinder section 53 side).
The die 59 is a die disposed at the downstream end of the barrel unit 51, and has a discharge port having a predetermined nozzle shape. The acrylic rubber dried in the dryer cylinder 54 is extruded into a shape corresponding to a predetermined nozzle shape by passing through the discharge port of the die 59. The acrylic rubber passing through the die 59 can be molded into various shapes such as a pellet, a column, a round bar, a sheet, etc., depending on the nozzle shape of the die 59, and is molded into a sheet in the present invention. Between the screw and the die 59, a perforated plate, a metal mesh, or the like may be provided.
The aqueous pellets of the acrylic rubber obtained through the cleaning step are supplied from the feed port 55 to the supply cylinder portion 52. The aqueous pellets supplied to the supply cylinder section 52 are transported from the supply cylinder section 52 to the dehydration cylinder section 53 by rotation of a pair of screws in the cylinder unit 51. In the dewatering cylinder 53, the dewatering slits 56a, 56b, and 56c provided in the 1 st to 3 rd dewatering cylinders 53a to 53c are used to drain water and steam contained in the aqueous pellets, respectively, and the aqueous pellets are dewatered as described above.
The hydrous pellets dehydrated in the dehydration cylinder section 53 are conveyed to the dryer cylinder section 54 by the rotation of a pair of screws in the cylinder unit 51. The aqueous pellets sent to the dryer section 54 are plasticized and mixed into a molten mass, and are sent downstream while being heated by heat release. Then, the moisture contained in the acrylic rubber melt is vaporized, and the moisture (vapor) is discharged to the outside through exhaust pipes, not shown, connected to the respective exhaust ports 58a, 58b, 58c, 58 d.
As described above, the aqueous pellets are dried by the dryer barrel 54 to obtain a melt of the acrylic rubber, which is supplied to the die 59 by the rotation of the pair of screws in the barrel unit 51, and extruded from the die 59.
Here, an example of the operating conditions of the screw type biaxial extrusion dryer 5 of the present embodiment is given.
The number of rotations (N) of the pair of screws in the barrel unit 51 may be appropriately selected depending on the respective conditions, and is usually 10 to 1000rpm, preferably 50 to 750rpm, more preferably 100 to 500rpm, and most preferably 120 to 300rpm, from the viewpoint of being able to efficiently reduce the water content of the acrylic rubber and the amount of methyl ethyl ketone insoluble components.
The extrusion amount (Q) of the acrylic rubber is not particularly limited, but is usually 100 to 1500 kg/hr, preferably 300 to 1200 kg/hr, more preferably 400 to 1000 kg/hr, and most preferably 500 to 800 kg/hr.
The ratio (Q/N) of the extrusion amount (Q) of the acrylic rubber to the number of revolutions (N) of the screw is not particularly limited, but is usually 1 to 20, preferably 2 to 10, more preferably 3 to 8, particularly preferably 4 to 6.
The maximum torque in the barrel unit 51 is not particularly limited, and is usually in the range of 30 to 100n·m, preferably in the range of 35 to 75n·m, and more preferably in the range of 40 to 60n·m.
The specific energy consumption in the cylinder unit 51 is not particularly limited, but is usually 0.1 to 0.25[ kw.h/kg ] or more, preferably 0.13 to 0.23[ kw.h/kg ], and more preferably 0.15 to 0.2[ kw.h/kg ].
The specific power in the cylinder unit 51 is not particularly limited, but is usually 0.2 to 0.6[ A.multidot.h/kg ] or more, preferably 0.25 to 0.55[ A.multidot.h/kg ], and more preferably 0.35 to 0.5[ A.multidot.h/kg ].
The shear rate in the barrel unit 51 is not particularly limited, but is usually 40 to 150[ l/s ] or more, preferably 45 to 125[ l/s ], and more preferably 50 to 100[ l/s ].
The shear viscosity of the acrylic rubber in the cylinder unit 51 is not particularly limited, but is usually 4000 to 8000[ Pa.s ] or less, preferably 4500 to 7500[ Pa.s ], and more preferably 5000 to 7000[ Pa.s ].
The cooling device 6 shown in fig. 1 is configured to cool the dried rubber obtained through the dehydration step by a dehydrator and the drying step by a dryer. As the cooling method by the cooling device 6, various methods including an air cooling method by blowing or cooling air, a water spraying method, a dipping method in water, and the like can be employed. In addition, the rubber may also be dried by cooling at room temperature.
As described above, the dried rubber discharged from the screw extruder 5 is extruded into various shapes such as a pellet, a column, a round bar, a sheet, etc., according to the nozzle shape of the die 59, and is molded into a sheet in the present invention. A conveyor type cooling device 60 for cooling the sheet-shaped dried rubber 10 molded into a sheet shape, which is an example of the cooling device 6, will be described below with reference to fig. 3.
Fig. 3 shows a structure of a transport type cooling device 60 which is preferable as the cooling device 6 shown in fig. 1. The conveying type cooling device 60 shown in fig. 3 is configured to cool by an air cooling method while conveying the sheet-like dry rubber 10 discharged from the discharge port of the die 59 of the screw extruder 5. By using this conveyor cooling device 60, the sheet-like dry rubber discharged from the screw extruder 5 can be cooled preferably.
The conveying type cooling device 60 shown in fig. 3 is used in direct connection with the die 59 of the screw type extruder 5 shown in fig. 2, for example, or is disposed in the vicinity of the die 59.
The conveying type cooling device 60 has a conveyor 61 that conveys the sheet-like dry rubber 10 discharged from the die 59 of the screw type extruder 5 in the direction of arrow a in fig. 3, and a cooling unit 65 that blows cool air to the sheet-like dry rubber 10 on the conveyor 61.
The conveyor 61 has rollers 62, 63, and a conveyor belt 64 wound around these rollers 62, 63 in tension and on which the sheet-like dry rubber 10 is placed. The conveyor 61 is configured to continuously convey the sheet-like dry rubber 10 discharged from the die 59 of the screw extruder 5 to the downstream side (right side in fig. 3) on the conveyor belt 64.
The cooling unit 65 is not particularly limited, and examples thereof include a cooling unit having a structure capable of blowing cooling air sent from a cooling air generating unit, not shown, onto the surface of the sheet-like dry rubber 10 on the conveyor belt 64.
The length L1 of the conveyor 61 and the cooling unit 65 of the transport type cooling device 60 (the length of the portion capable of blowing cooling air) is not particularly limited, and is, for example, 10 to 100m, preferably 20 to 50m. The conveying speed of the sheet-like dry rubber 10 in the conveying type cooling device 60 may be appropriately adjusted according to the length L1 of the conveyor 61 and the cooling unit 65, the discharge speed of the sheet-like dry rubber 10 discharged from the die 59 of the screw extruder 5, the target cooling speed, the cooling time, and the like, and is, for example, 10 to 100 m/hr, and more preferably 15 to 70 m/hr.
According to the conveying type cooling device 60 shown in fig. 3, the sheet-like dry rubber 10 discharged from the die 59 of the screw extruder 5 is conveyed by the conveyor 61, and cooling air from the cooling unit 65 is blown onto the sheet-like dry rubber 10, whereby the sheet-like dry rubber 10 is cooled.
The transport cooling device 60 is not particularly limited to the configuration having 1 conveyor 61 and 1 cooling unit 65 as shown in fig. 3, and may have a configuration having 2 or more conveyors 61 and 2 or more cooling units 65 corresponding thereto. In this case, the total length of the 2 or more conveyors 61 and the cooling unit 65 may be set to the above range.
The glue coating device 7 shown in fig. 1 is constituted as follows: the dried rubber extruded from the screw extruder 5 and cooled by the cooling device 6 is processed to produce a bale as a single piece. As described above, the screw extruder 5 can extrude the dried rubber into various shapes such as pellets, columns, round bars, and sheets, and the rubber coating device 7 is configured to carry out rubber coating on the dried rubber thus molded into various shapes. The weight, shape, etc. of the acrylic rubber bag manufactured by the rubber bag forming apparatus 7 are not particularly limited, and for example, an acrylic rubber bag having a substantially rectangular parallelepiped shape of about 20kg can be manufactured.
The rubber packing device 7 may have, for example, a packer by which the cooled dry rubber is compressed to manufacture an acrylic rubber packing.
In addition, in the case of producing the sheet-like dry rubber 10 by the screw extruder 5, an acrylic rubber bag in which the sheet-like dry rubber 10 is laminated can be produced. For example, a cutter mechanism for cutting the sheet-like dry rubber 10 may be provided in the rubber packing device 7 disposed downstream of the conveyor-type cooling device 60 shown in fig. 3. Specifically, the cutting mechanism of the glue wrapping apparatus 7 is configured as follows, for example: the cooled sheet-like dried rubber 10 is continuously cut at predetermined intervals, and processed into a sheet-like dried rubber 16 of a predetermined size. By stacking a plurality of pieces of the sliced dried rubber 16 cut into a predetermined size by a cutting mechanism, an acrylic rubber bag in which the sliced dried rubber 16 is stacked can be manufactured.
In the case of producing an acrylic rubber bag in which the sliced dried rubber 16 is laminated, it is preferable to laminate the sliced dried rubber 16 at 40 ℃ or higher, for example. By stacking the sliced dried rubber 16 at 40 ℃ or higher, good air discharge can be achieved by further cooling and compression by its own weight.
Examples
Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples. Unless otherwise specified, "parts", "%" and "ratio" in each example are on a weight basis. The physical properties and the like of the various materials were evaluated by the following methods.
[ monomer composition ]
Regarding the monomer composition in the acrylic rubber, the polymerization is carried out by 1 The monomer structure of each monomer unit in the acrylic rubber was confirmed by H-NMR, and the residual activity of the reactive group and the content of each reactive group in the acrylic rubber were confirmed by the following method. The content ratio of each monomer unit in the acrylic rubber is calculated from the amount of each monomer used for polymerization reaction and the polymerization conversion rate. Specifically, since the polymerization reaction is an emulsion polymerization reaction and the polymerization conversion rate is approximately 100% which cannot be confirmed by the unreacted monomers, the content ratio of each monomer unit in the rubber is the same as the amount of each monomer used.
[ reactive group content ]
The content of the reactive group in the acrylic rubber bag was measured by the following method.
(1) The carboxyl group amount was calculated by dissolving a sample (acrylic rubber bag) in acetone and potentiometric titration with potassium hydroxide solution.
(2) The epoxy group amount was calculated by dissolving a sample in methyl ethyl ketone, adding a predetermined amount of hydrochloric acid thereto to react with the epoxy group, and titrating the residual hydrochloric acid amount with potassium hydroxide.
(3) The chlorine content was calculated by completely burning the sample in a burning flask, absorbing the generated chlorine with water, and titrating with silver nitrate.
[ Ash content ]
The ash content (%) contained in the acrylic rubber bag was measured in accordance with JIS K6228A method.
[ ash component amount ]
The amount (ppm) of each component in the acrylic rubber-coated ash was obtained by pressing ash collected at the time of measuring the ash against titration filter paper having a diameter of 20mm, and measuring XRF using ZSX Primus (manufactured by Kyowa Co., ltd.).
[ molecular weight and molecular weight distribution ]
The molecular weight (Mw, mn, mz) and the molecular weight distribution (Mw/Mn and Mz/Mw) of the acrylic rubber are the absolute molecular weight and the absolute molecular weight distribution measured by GPC-MALS method using a solution in which lithium chloride was added to dimethylformamide as a solvent at a concentration of 0.05mol/L and 37% concentrated hydrochloric acid was added at a concentration of 0.01%.
The structure of the gel permeation chromatography multi-angle light scattering photometer as a main device was composed of a pump (manufactured by LC-20ADOpt corporation, shimadzu corporation) and a differential refractive detector (manufactured by Optilab rEX Huai Ya trickplay company) as a detector, and a multi-angle light scattering detector (manufactured by DAWN HELEOS Huai Ya trickplay company).
Specifically, a multi-angle laser light scattering detector (MALS) and a differential refractive index detector (RI) were assembled in a GPC (Gel Permeation Chromatography) apparatus, and the light scattering intensity and refractive index difference of a molecular chain solution classified by size were measured by a GPC apparatus according to elution time, whereby the molecular weight of a solute and its content were calculated in order. The measurement conditions and measurement methods using the GPC apparatus are as follows.
Column: TSKgel alpha-M2 root%
Figure BDA0004113517400000581
Manufactured by Tosoh corporation
Column temperature: 40 DEG C
Flow rate: 0.8ml/mm
Sample preparation: to 10mg of the sample (acrylic rubber bag) was added 5ml of the solvent, and the mixture was stirred slowly at room temperature (dissolution was visually confirmed). Then, filtration was performed using a 0.5 μm filter.
[ glass transition temperature (Tg) ]
The glass transition temperature (Tg) of the acrylic rubber was measured by a differential scanning calorimeter (DSC, product name "X-DSC7000", manufactured by Hitachi high technology, co., ltd.).
[ amount of methyl ethyl ketone insoluble component ]
The amount (%) of methyl ethyl ketone insoluble component in the acrylic rubber bag was determined as the amount of the insoluble component in methyl ethyl ketone by the following method.
About 0.2g (Xg) of an acrylic rubber bag was weighed, immersed in 100ml of methyl ethyl ketone, left at room temperature for 24 hours, and then insoluble components in methyl ethyl ketone were filtered using an 80 mesh metal mesh to obtain a filtrate in which only the methyl ethyl ketone-soluble rubber component was dissolved, and the filtrate was evaporated, dried and solidified, and the obtained dry solid component (Yg) was weighed and calculated by the following formula.
Methyl ethyl ketone insoluble component amount (%) =100× (X-Y)/X
[ specific gravity ]
The specific gravity of the acrylic rubber bag was measured in accordance with JIS K6268 crosslinked rubber-density measurement method A.
The measured value obtained by the following measuring method was the density, and the density of water was 1Mg/m 3 As specific gravity. Specifically, the specific gravity of the rubber sample obtained by the method a according to JIS K6268 crosslinked rubber-density measurement is the specific gravity obtained by dividing the mass of the rubber sample by the volume of the voids containing the rubber sample, and the specific gravity obtained by dividing the density of the rubber sample obtained by the method a according to JIS K6268 crosslinked rubber-density measurement by the density of water (when the density of the rubber sample is divided by the density of water, the values are the same, and the unit disappears). In detail, the base The specific gravity of the rubber sample was determined in the following steps.
(1) From a rubber sample which was left to stand at a standard temperature (23 ℃ + -2 ℃) for at least 3 hours, 2.5g of a test piece was cut out, and a fine nylon yarn having a mass of less than 0.010g was used, and the test piece was hung from a hook on a chemical balance having an accuracy of 1mg so that the bottom edge of the test piece was 25mm or more from the tray for the chemical balance, and the mass (m 1) of the test piece was measured in the atmosphere for 2 times until mg was measured.
(2) Next, 250cm of the sample was placed on a chemical balance tray 3 The beaker was filled with distilled water which was boiled and cooled to a standard temperature, the test piece was immersed therein, bubbles adhering to the surface of the test piece were removed, the swinging of the pointer of the balance was observed for several seconds, it was confirmed that the pointer was not slowly swung by convection, and the mass (m 2) of the test piece in water was measured in mg units for 2 times.
(3) In addition, when the density of the test piece is less than 1Mg/m 3 When the test piece was floated in water, a weight was added to the test piece, and the mass of the weight in water (m 3), the mass of the test piece, and the mass of the weight (m 4) were measured 2 times in mg units.
(4) Using the average value of each of m1, m2, m3, and m4 measured as described above, the density (Mg/m) was calculated based on the following formula 3 ) The calculated density divided by the density of water (1.00 Mg/m 3 ) The specific gravity of the rubber sample was determined.
(Density of rubber sample when weight is not used)
Density=m1/(m 1-m 2)
(Density of rubber sample when weight was used)
Density=m1/(m1+m3-m 4)
[ Water content ]
Moisture content (%) according to JIS K6238-1: the measurement was performed by the oven a (volatile component measurement) method.
[pH]
After dissolving 6g (+ -0.05 g) of the acrylic rubber bag with 100g of tetrahydrofuran, 2.0ml of distilled water was added thereto, and after confirming complete dissolution, the pH was measured with a pH electrode.
[ Complex viscosity ]
The complex viscosity η was determined by measuring the temperature dispersion (40 to 120 ℃) at a deformation of 473% and 1Hz using a dynamic viscoelasticity measuring device "rubber processing analyzer RPA-2000" (manufactured by alpha technology Co., ltd.). Here, the ratio η (100 ℃) to η (60 ℃) was calculated by taking the dynamic viscoelasticity at 60℃as the complex viscosity η (60 ℃) and the dynamic viscoelasticity at 100℃as the complex viscosity η (100 ℃).
[ Mooney viscosity (ML1+4, 100 ℃)
Mooney viscosity (ML1+4, 100 ℃ C.) was measured according to the uncrosslinked rubber physical test method of JIS K6300.
[ Cross-Linkability ]
The crosslinkability of the rubber sample was determined by calculating the ratio of the change in the breaking strength of the rubber crosslinked material subjected to the secondary crosslinking for 2 hours to the change in the breaking strength of the rubber crosslinked material subjected to the secondary crosslinking for 4 hours ((breaking strength of the 4-hour crosslinked rubber crosslinked material/breaking strength of the 2-hour crosslinked rubber crosslinked material) ×100) according to the following criteria.
And (3) the following materials: the change rate of the breaking strength is less than 10 percent
X: the change rate of the breaking strength is more than 10 percent
[ roll processability ]
The roll processability of the rubber sample was evaluated by observing the roll-winding property and the state of the rubber when the rubber sample was rolled, according to the following criteria.
And (3) the following materials: the rubber composition was easily kneaded and wound around a roll, and separation from the roll was not observed, and the surface of the rubber composition after kneading was smooth
O: the kneading was easy, winding around the rolls was easy, separation from the rolls was not observed, and irregularities were slightly observed on the surface of a part of the rubber composition after kneading.
And ∈: the kneading is easy, the roll winding property is excellent, and the surface of the rubber composition after the kneading has a little concave-convex.
Delta: the kneading was easy, the roll-winding property was slightly poor, and the surface of the rubber composition after kneading was rough.
X: the kneading is loaded and the roll windability is poor
[ Banbury processability ]
For the banbury processability of the rubber sample, the rubber sample was put into a banbury mixer heated to 50 ℃ and plasticated for 1 minute, and then, compounding agent a of the rubber mixture described in table 1 was put into the mixer, and the time for which the rubber mixture in the first stage was integrated to exhibit the maximum torque value, that is, BIT (Black Incorporation Time, carbon black mixing time) was measured, and the index of comparative example 2 was evaluated as 100 (the smaller the index, the more excellent the processability).
[ evaluation of storage stability ]
For the storage stability of the rubber sample, the rubber sample was put into a constant temperature and humidity tank (SH-222 manufactured by espek) at 45 ℃ x 80% rh, and the change rate of the water content before and after the test was calculated for 7 days, and the evaluation was made with the index of comparative example 2 as 100 (the smaller the index, the more excellent the storage stability).
[ evaluation of Water resistance ]
For the water resistance of the rubber sample, an immersion test was performed in which the crosslinked product of the rubber sample was immersed in distilled water at 85℃for 100 hours in accordance with JIS K6258, and the volume change rate before and after immersion was calculated in accordance with the following formula, and the evaluation was made with the index of comparative example 2 as 100 (the smaller the index, the more excellent the water resistance).
Rate of change in volume (%) = ((volume of test piece after immersion-volume of test piece before immersion) before and after immersion
Test piece volume before immersion) ×100
[ compression set resistance ]
The compression set resistance of the rubber sample was evaluated according to JIS K6262, by measuring the compression set after leaving the rubber crosslinked product of the rubber sample to stand at 175℃for 90 hours in a state of being compressed by 25%.
And (3) the following materials: compression set of less than 15%
X: compression set of 15% or more
[ evaluation of physical Properties in Normal state ]
The normal physical properties of the rubber sample were measured according to JIS K6251, and the breaking strength, 100% tensile stress and elongation at break of the rubber crosslinked product of the rubber sample were evaluated according to the following criteria.
(1) For the breaking strength, 10MPa or more was evaluated as excellent, and less than 10MPa was evaluated as x.
(2) For 100% tensile stress, 5MPa or more was rated as excellent, and less than 5MPa was rated as X.
(3) Regarding the elongation at break, 150% or more was evaluated as excellent, and less than 150% was evaluated as x.
[ evaluation of deviation of the amount of insoluble methyl ethyl ketone ]
For the evaluation of the deviation of the methyl ethyl ketone insoluble content of the rubber sample, the methyl ethyl ketone insoluble content of 20 points arbitrarily selected from 20 parts (20 kg) of the rubber sample was measured, and the evaluation was performed based on the following criteria.
And (3) the following materials: calculating the average value of the measured methyl ethyl ketone insoluble component amounts at 20 points, wherein the measured methyl ethyl ketone insoluble component amounts at 20 points are all within the average value + -3
And (2) the following steps: calculating the average value of the methyl ethyl ketone insoluble component amounts at 20 points, wherein the measured 20 points are all within the range of the average value.+ -. 5 (1 point out of the measured 20 points is outside the range of the average value.+ -. 3, but the 20 points are all within the range of the average value.+ -. 5)
X: calculating the average value of the measured methyl ethyl ketone insoluble component amounts at 20 points, wherein 1 point out of the measured 20 points is out of the range of + -5 of the average value
[ evaluation of processing stability of Mooney scorch inhibition ]
The mooney scorch stability of the acrylic rubber composition was evaluated with respect to the cooling rate of the sheet-like acrylic rubber extruded from the screw type biaxial extrusion dryer described in japanese patent No. 6683189.
Example 1
As shown in Table 2-1, 46 parts of pure water, 4.5 parts of ethyl acrylate, 64.5 parts of n-butyl acrylate, 29.5 parts of methoxyethyl acrylate, 1.5 parts of mono-n-butyl fumarate, and 1.8 parts of sodium octoxyethylenephosphate as an emulsifier were added to a mixing vessel having a homogenizer, and stirred to obtain a monomer emulsion.
Into a polymerization reaction vessel equipped with a thermometer and a stirring device, 170 parts of pure water and 3 parts of the monomer emulsion obtained above were charged, and after cooling to 12℃under a nitrogen stream, 0.00033 parts of ferrous sulfate, 0.02 parts of sodium ascorbate, and 0.2 parts of potassium persulfate as an inorganic radical generator were added to initiate polymerization. The polymerization reaction was continued by maintaining the temperature in the polymerization reaction vessel at 23℃and continuously dropping the remaining portion of the monomer emulsion over 3 hours, adding 0.0072 part of n-dodecyl mercaptan after 50 minutes of initiation of the reaction, adding 0.0036 part of n-dodecyl mercaptan after 100 minutes, and adding 0.4 part of sodium L-ascorbate after 120 minutes, and stopping the polymerization reaction by adding hydroquinone as a polymerization terminator when the polymerization conversion rate reached approximately 100%, to obtain an emulsion polymerization solution.
Next, in a coagulation tank having a thermometer and a stirring device, the emulsion polymerization liquid obtained above was heated to 80 ℃ and continuously added to 350 parts of a 2% magnesium sulfate aqueous solution (coagulation liquid using magnesium sulfate as a coagulant) heated to 80 ℃ and vigorously stirred with a stirring blade of the stirring device at 600 revolutions (circumferential speed 3.1 m/s), and the polymer was coagulated to obtain a coagulated slurry containing aggregates of acrylic rubber as a coagulated material and water. The granules were filtered from the slurry obtained, and water was discharged from the solidified layer to obtain aqueous granules.
194 parts of hot water (70 ℃) was added to the coagulation tank in which the filtered aqueous pellets remained and stirred for 15 minutes, the aqueous pellets were washed, then the water was discharged, 194 parts of hot water (70 ℃) was added again and stirred for 15 minutes, and washing of the aqueous pellets was performed (the total number of washing times was 2). The washed aqueous pellet (aqueous pellet temperature 65 ℃) was fed to a screw type biaxial extrusion dryer 15, dehydrated and dried, and a sheet-like dried rubber having a width of 300mm and a thickness of 10mm was extruded. Then, the sheet-like dry rubber was cooled at a cooling rate of 200℃per hour using a conveyor type cooling device provided in direct connection with the screw type biaxial extrusion dryer 15.
The screw type biaxial extrusion dryer used in example 1 was composed of 1 feeder cylinder, 3 dehydrators (1 st to 3 rd dehydrators), and 5 dryer cylinders (1 st to 5 th dryer cylinders). The 1 st dewatering cylinder discharges water, and the 2 nd and 3 rd dewatering cylinders discharge steam. The operating conditions of the screw type biaxial extrusion dryer are as follows.
Water content:
water content of the aqueous pellet after draining of the 1 st dewatering barrel: 20 percent of
Water content of the aqueous pellets after steam venting in the 3 rd dewatering barrel: 10 percent of
Moisture content of the aqueous pellets after drying in the 5 th dryer barrel: 0.4%
Rubber temperature:
temperature of the aqueous pellets fed to the feed barrel: 65 DEG C
Temperature of rubber discharged from screw type biaxial extrusion dryer: 140 DEG C
Set temperature of each barrel:
1 st dewatering barrel: 100 DEG C
2 nd dewatering barrel: 120 DEG C
3 rd dewatering barrel: 120 DEG C
1 st dryer barrel: 120 DEG C
Dryer barrel 2: 130 DEG C
3 rd dryer barrel: 140 DEG C
4 th dryer barrel: 160 DEG C
5 th dryer barrel: 180 DEG C
Operating conditions:
diameter of screw (D): 132mm
Full length of screw (L): 4620mm
·L/D：35
Revolution of screw: 135rpm
Vacuum of the dryer barrel: 10kPa
Extrusion amount of rubber extruded from die: 700 kg/hr
Resin pressure in die: 2MPa of
Maximum torque in screw type biaxial extrusion dryer: 15 N.m
The extruded sheet-like dry rubber was cooled to 50℃and then cut by a cutter, and 20 parts (20 kg) of the sheet-like dry rubber was laminated to obtain an acrylic rubber bag (A) before the temperature was lowered to 40℃or lower. The reactive group content, ash component content, methyl ethyl ketone insoluble component content, pH, specific gravity, glass transition temperature (Tg), water content, molecular weight distribution, and complex viscosity at 100℃and 60℃of the obtained acrylic rubber bag (A) were measured and are shown in tables 2-2. Further, the storage stability test of the acrylic rubber bag (A) was conducted to determine the water content change rate, and the results are shown in Table 2-2.
Next, 100 parts of the acrylic rubber bag (A) and the compounding agent A of "compounding 1" shown in Table 1 were charged into the Banbury mixer, and mixed at 50℃for 5 minutes (first-stage mixing). BIT at this time was measured, and the Banbury processability of the acrylic rubber bag (A) was evaluated, and the results are shown in Table 2-2.
Next, the resulting mixture was moved to a roller at 50℃and blended with the compounding agent B of "compounding 1" (second stage mixing) to obtain a rubber composition. The roll processability at this time was evaluated, and the results are shown in Table 2-2.
TABLE 1
Figure BDA0004113517400000651
1: SEAST 3 (HAF) in the table is carbon black (manufactured by Tokida carbon Co., ltd.).
2: NOCRAC CD in the tables is 4,4' -bis (. Alpha.,. Alpha. -dimethylbenzyl) diphenylamine (manufactured by Dain Ind Chemie Co., ltd.).
3: rhenotran xLA-60 in the table is a vulcanization accelerator (manufactured by Langsheng Co.).
The obtained rubber composition was placed in a metal mold having a length of 15cm, a width of 15cm and a depth of 0.2cm, and was pressed at 180℃for 10 minutes while being pressurized by a pressing pressure of 10MPa, whereby primary crosslinking was performed, and the obtained primary crosslinked product was further heated by a Gill oven at 180℃for 2 hours to perform secondary crosslinking, whereby a sheet-like crosslinked rubber product was obtained. Then, a test piece of 3 cm. Times.2 cm. Times.0.2 cm was cut out from the resulting sheet-like crosslinked rubber, and the water resistance, compression set resistance and normal physical properties were evaluated. Further, the sheet-like rubber crosslinked material subjected to secondary crosslinking for 2 hours was measured for its normal physical properties, and the crosslinkability was evaluated. The results are shown in Table 2-2.
Example 2
An acrylic rubber bag (B) was obtained in the same manner as in example 1, except that the emulsifier was changed to 1.8 parts of nonylphenoxy hexaoxyethylene phosphate sodium salt, the amount of the inorganic radical generator potassium persulfate was changed to 0.21 part, and further, the post-addition of the chain transfer agent n-dodecyl mercaptan was changed to 0.017 part after 50 minutes, 0.017 part after 100 minutes and 0.017 part after 120 minutes, and the properties were evaluated. The results are shown in Table 2-2.
Reference example 1
An acrylic rubber bag (C) was obtained in the same manner as in example 1 except that the monomer components were changed to 48.25 parts of ethyl acrylate, 50 parts of n-butyl acrylate and 1.75 parts of mono-n-butyl fumarate, the emulsifier was changed to 1.8 parts of sodium tridecyloxy hexaoxyethylene phosphate, and the washed aqueous pellets were dried to a water content of 0.4% by using a hot air dryer at 160℃to obtain pellet-like acrylic rubber, which was then packed in a 300X 650X 300mm packer and compacted at a pressure of 3MPa for 25 seconds to obtain a rubber bag-like acrylic rubber. The properties of the acrylic rubber bag (C) were evaluated (the compounding agent was changed to "compounding 2"), and the results are shown in Table 2-2.
Reference example 2
An acrylic rubber bag (D) was obtained in the same manner as in reference example 1 except that the monomer components were changed to 28 parts of ethyl acrylate, 38 parts of n-butyl acrylate, 27 parts of methoxyethyl acrylate, 5 parts of acrylonitrile and 2 parts of allyl glycidyl ether, and each characteristic was evaluated (the compounding agent was changed to "compounding 3"). The results are shown in Table 2-2.
Reference example 3
An acrylic rubber bag (E) was obtained in the same manner as in reference example 1 except that the monomer components were changed to 42.2 parts of ethyl acrylate, 35 parts of n-butyl acrylate, 20 parts of methoxyethyl acrylate, 1.5 parts of acrylonitrile and 1.3 parts of vinyl chloride acetate, and each characteristic was evaluated (the compounding agent was changed to "compounding 4"). The results are shown in Table 2-2.
Reference example 4
An acrylic rubber bag (F) was obtained in the same manner as in example 2 except that the monomer components were changed to 48.25 parts of ethyl acrylate, 50 parts of n-butyl acrylate and 1.75 parts of mono-n-butyl fumarate, the emulsifier was changed to 1.8 parts of sodium tridecyloxy hexaoxyethylene phosphate, and the washed aqueous pellets were dried to a water content of 0.4% by using a hot air dryer at 160℃to obtain pellet-like acrylic rubber, which was then packed in a 300X 650X 300mm packer and compacted at a pressure of 3MPa for 25 seconds to obtain a rubber bag-like acrylic rubber. The properties of the acrylic rubber bag (F) were evaluated (the compounding agent was changed to "compounding 2"), and the results are shown in Table 2-2.
Reference example 5
An acrylic rubber bag (G) was obtained in the same manner as in reference example 4 except that the monomer components were changed to 28 parts of ethyl acrylate, 38 parts of n-butyl acrylate, 27 parts of methoxyethyl acrylate, 5 parts of acrylonitrile and 2 parts of allyl glycidyl ether, and each characteristic was evaluated (the compounding agent was changed to "compounding 3"). The results are shown in Table 2-2.
Reference example 6
An acrylic rubber bag (H) was obtained in the same manner as in reference example 4 except that the monomer components were changed to 42.2 parts of ethyl acrylate, 35 parts of n-butyl acrylate, 20 parts of methoxyethyl acrylate, 1.5 parts of acrylonitrile and 1.3 parts of vinyl chloride acetate, and each characteristic was evaluated (the compounding agent was changed to "compounding 4"). The results are shown in Table 2-2.
Reference example 7
The procedure of reference example 6 was repeated except that the amount of the inorganic radical generator potassium persulfate was changed to 0.22 part, a chain transfer agent was not added, and the rubber was not baled with a baler to obtain a pellet-like acrylic rubber (I), and each property was evaluated. The results are shown in Table 2-2.
Comparative example 1
A pellet-like acrylic rubber (J) was obtained in the same manner as in reference example 7 except that a 0.7% aqueous magnesium sulfate solution was added to the stirred emulsion polymerization solution (stirring number 100rpm, circumferential speed 0.5 m/s) after emulsion polymerization to carry out a coagulation reaction, and each property was evaluated. The results are shown in Table 2-2.
Comparative example 2
The emulsifier was changed to 0.709 part of sodium lauryl sulfate and 1.82 parts of polyoxyethylene lauryl ether, the coagulation liquid was changed to 0.7% sodium sulfate aqueous solution, and the cleaning method was changed to: the procedure was carried out in the same manner as in comparative example 1 except that 194 parts of industrial water was added to 100 parts of the aqueous pellets after the coagulation reaction, the aqueous pellets were stirred at 25℃for 5 minutes in the coagulation tank, and then washed with water discharged from the coagulation tank, then 194 parts of an aqueous sulfuric acid solution having a pH of 3 was added, and after stirring at 25℃for 5 minutes, water was discharged from the coagulation tank, acid washing was carried out 1 time, 194 parts of pure water was added, and pure water washing was carried out 1 time, whereby a pellet-like acrylic rubber (K) was obtained, and each characteristic was evaluated. The results are shown in Table 2-2.
Comparative example 3
0.025 parts of chain transfer agent n-dodecyl mercaptan was continuously added to the monomer emulsion and the aqueous pellets were washed only 2 times with the following operations: a pellet-like acrylic rubber (L) was obtained in the same manner as in comparative example 2 except that 194 parts of industrial water was added and stirred in the coagulation tank at 25 ℃ for 5 minutes, and then water was discharged from the coagulation tank, whereby each property was evaluated. The results are shown in Table 2-2.
[ Table 2-1]
Figure BDA0004113517400000691
[ Table 2-2]
Figure BDA0004113517400000701
As is clear from tables 2-1 and 2-2, the acrylic rubber bags (A) to (B) of the present invention are composed of acrylic rubber having at least one reactive group selected from the group consisting of carboxyl groups, epoxy groups and chlorine atoms, having a weight average molecular weight (Mw) of 1000000 ～ 3500000 in terms of absolute molecular weight and absolute molecular weight distribution measured by GPC-MALS method, a ratio (Mw/Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) of 3.7 to 6.5, a methyl ethyl ketone insoluble content of 50% by weight or less, an ash content of 0.2% by weight or less, and a total amount of sodium, magnesium, calcium, phosphorus and sulfur in ash of 50% by weight or more, and are excellent in roll processability, banbury workability, water resistance, compression set resistance and physical properties including strength characteristics, and also excellent in crosslinking property and storage stability (examples 1 to 2).
Further, as is clear from tables 2 to 2, the acrylic rubber bags (a) to (L) produced under the conditions of examples, reference examples and comparative examples of the present invention have a carboxyl group, an epoxy group and a plasma-reactive group such as a chlorine atom, and the weight average molecular weight (Mw) of the absolute molecular weight measured by GPC-MALS method is high and exceeds 100 ten thousand, and therefore all of the crosslinking property, compression set resistance and normal physical properties including strength characteristics are excellent in a short period of time (examples 1 to 2, reference 1 to 7 and comparative examples 1 to 3). However, the pellet-like acrylic rubbers (J) to (L) of comparative examples 1 to 3 were excellent in crosslinking property, compression set resistance and strength characteristics, but were inferior in roll processability, banbury processability, water resistance and storage stability (comparative examples 1 to 2), and were inferior in roll processability, water resistance and storage stability (comparative example 3).
As is clear from table 2-2, in the case where the weight average molecular weight (Mw) is between 100 ten thousand and 350 ten thousand and the ratio (Mw/Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) is large, it is preferably 3.5 or more, more preferably 3.7 or more, and still more preferably 4 or more, the strength characteristics of the acrylic rubber bag are not impaired in this case, and the roll processability can be significantly improved (comparison of examples 1 to 2 with comparative examples 1 to 3).
As is clear from tables 2-1 and 2-2, by elongating 1 polymerization chain with an inorganic radical generator and adding a chain transfer agent (n-dodecylmercaptan) in portions thereafter, it is possible to realize an acrylic rubber having a large Mw and a broad Mw/Mn, which is excellent in strength characteristics and roll processability (examples 1-2 and reference examples 1-6). Further, it was found that in order to efficiently expand Mw/Mn, the influence of the number of times of post-batch addition of the chain transfer agent was large, the Mw/Mn of one of 2 times was widened compared with the number of times of post-batch addition of 3 times (comparison of reference examples 1 to 3 and reference examples 4 to 6), and when the chain transfer agent was continuously added, the Mw/Mn expansion was small, and the improvement of roll processability was limited (comparative example 3). This is presumably because, although the GPC-MALS method does not show a complete double peak in the chart, the chain transfer agent is added after the chain transfer agent is added in portions, so that the Mw/Mn is widened and the roll processability is greatly improved. In addition, although not shown in table 2-1, in the present example, sodium ascorbate as a reducing agent was added 120 minutes after the start of polymerization, whereby the formation of the high molecular weight component of the acrylic rubber was facilitated, and the effect of enlarging Mw/Mn of the post-addition of the chain transfer agent was increased. Further, although not shown in table 2-1, when an organic radical generator is used instead of an inorganic radical generator, mw/Mn becomes small, and roll processability is remarkably lowered, so that it is not preferable.
As is clear from tables 2 to 2, the banbury workability of the acrylic rubber bag was excellent in terms of the amount of the methyl ethyl ketone insoluble component, and the amount of the methyl ethyl ketone insoluble component was small. It is found that, particularly, when the methyl ethyl ketone insoluble content is 50 wt% or less, preferably 30 wt% or less, the acrylic rubber is excellent in the banbury workability (comparison of reference examples 1 to 6 and comparative example 3 with reference examples 7 and comparative examples 1 to 2), and when the methyl ethyl ketone insoluble content is 10 wt% or less, preferably 5 wt% or less, the acrylic rubber is extremely excellent in the banbury workability (examples 1 to 2). It was found that the amount of methyl ethyl ketone insoluble components in the acrylic rubber bag (reference examples 1 to 6 and comparative example 3) can be reduced by performing emulsion polymerization in the presence of a chain transfer agent, and particularly when the polymerization conversion rate is increased in order to improve the strength characteristics, the amount of methyl ethyl ketone insoluble components increases sharply, and therefore, the production of methyl ethyl ketone insoluble components can be suppressed in reference examples 1 to 6 in which a chain transfer agent is added after the latter half of polymerization. Further, by drying the aqueous pellets with a screw type biaxial extrusion dryer, the amount of methyl ethyl ketone insoluble components in the acrylic rubber bag was significantly reduced, and the banbury processability of the produced acrylic rubber bag was significantly improved (comparison of examples 1 to 2 and reference examples 1 to 6). In the present invention, although not shown in the present example, it was confirmed that the melt kneading was carried out in a screw-type biaxial extrusion dryer in a state substantially free of moisture (moisture content less than 1% by weight), and the methyl ethyl ketone insoluble component (comparative examples 1 and 2) which was rapidly increased in emulsion polymerization without adding a chain transfer agent was disappeared, and the strength characteristics were not impaired, and the banbury processability was significantly improved.
As is clear from tables 2 to 2, the acrylic rubber packs (A) to (B) of examples 1 to 2 of the present invention were excellent in water resistance, and the acrylic rubber packs (C) to (I) of reference examples 1 to 7 were excellent, as compared with the pellet-like acrylic rubbers (J) to (L) of comparative examples 1 to 3. As is clear from the observation of the influence of the difference in the ion-reactive groups on the water resistance in reference examples 1 to 7 having the same ash amount, the acrylic rubber bags (C, F) of reference examples 1 and 4 having carboxyl groups and the acrylic rubber bags (D, G) of reference examples 2 and 5 having epoxy groups were 2 times more excellent than the acrylic rubber bags (E, H, I) of reference examples 3, 6 and 7 having chlorine atoms. It is apparent that the acrylic rubber packs (a) to (B) of the examples of the present invention, the acrylic rubber packs (C) to (I) of the reference examples, and the particulate acrylic rubber (J) to (L) of the comparative examples each have a total element amount of more than 90% by weight of phosphorus, magnesium, sodium, calcium, and sulfur in ash, and that the acrylic rubber is excellent in water resistance, mold releasability, and other characteristics, and in particular, even if the ash content is the same, one of the ash in which the ratio of phosphorus to magnesium is large is excellent in water resistance (comparison of reference example 7 and comparative example 2).
Further, as is clear from tables 2 to 2, regarding the water resistance of the acrylic rubber bag, the ash amount was greatly affected. The ash content of the acrylic rubber is difficult to remove during cleaning, and a large amount of ash containing phosphorus and magnesium components remains during cleaning of the aqueous pellets in the normal coagulation step (comparison of comparative example 1 and comparative example 2) as compared with ash containing sodium and sulfur components. However, it was found that even with ash containing a large amount of phosphorus and magnesium, the coagulant was prepared into a concentrated aqueous solution (coagulant) and stirred vigorously, and the emulsion polymerization solution after emulsion polymerization was added to the coagulant to carry out the coagulation reaction, and the resulting aqueous pellets were washed with hot water (reference examples 1 to 7); and dewatering the washed aqueous pellets (examples 1 to 2), whereby ash can be greatly reduced. Further, it was found that even if the ash content was the same, the water resistance of the acrylic rubber bag could be significantly improved by increasing the content of phosphorus and magnesium in the ash and defining the ratio of phosphorus to magnesium (comparison of reference examples 1 to 7 and comparative example 2). It was found that the water resistance of the acrylic rubber bag was different depending on the type of the reactive group, and that the carboxyl group and the epoxy group were more excellent than the chlorine atom (comparison of reference examples 1 to 2 and 3, and comparison of reference examples 4 to 5 and 6). Although not shown in tables 2-1 and 2-2, in the same production of acrylic rubber as in comparative example 2 (the ash content contains a large amount of sodium and sulfur), the water resistance can be significantly improved by performing the coagulation reaction and the washing in the same manner as in reference example 3, and the index of the water resistance can be improved to about 10 to 15 by dehydrating and drying the washed aqueous pellets in a screw type biaxial extrusion dryer in the same manner as in example 1, and the ash content can be 0.15 wt% or less, preferably 0.13 wt% or less. In addition, although the ash content can be reliably reduced up to the 3 rd time in the water washing at room temperature, the ash content reduction effect after the 4 rd time is hardly seen, although the 3 rd time and the 4 th time are hardly different from each other in terms of the influence of the number of washing times on the ash content in the acrylic rubber. On the other hand, in the hot water washing, the ash content in the acrylic rubber was reduced until the 2 nd time, and the washing effect after the 3 rd time was hardly seen.
As is clear from tables 2 to 2, the acrylic rubber bags (a) to (B) of the present invention are excellent in crosslinking property, roll processability, banbury processability, water resistance, compression set resistance and strength characteristics, and also are extremely excellent in storage stability (examples 1 to 2). It was found that the storage stability of the acrylic rubber bag was closely related to the specific gravity of the acrylic rubber bag, and when the specific gravity was large, air was not involved in the acrylic rubber, and the storage stability was excellent (comparative examples 1 to 2, reference examples 1 to 6, and comparative examples 1 to 3). The acrylic rubber bag having a large specific gravity can be obtained by compacting a granulated acrylic rubber by a packer to form a bag (reference examples 1 to 6), and more preferably by extruding the acrylic rubber bag into a sheet by a screw type biaxial extrusion dryer without involving air, cutting the sheet at a specific temperature, and laminating the sheet to form a bag (examples 1 to 2). In the present invention, it was found that, in particular, an acrylic rubber bag obtained by laminating acrylic rubber sheets obtained by melt-kneading and drying under reduced pressure, the storage stability was remarkably improved without impairing the short-time crosslinkability, roll processability, compression set resistance, normal physical properties including strength characteristics, and water resistance (examples 1 to 2). Further, it was found that the storage stability of the acrylic rubber bag was as low as the ash content (examples 1 and 2).
The acrylic rubber bags (A) to (B) of the present invention are composed of an acrylic rubber having at least one reactive group selected from a carboxyl group, an epoxy group and a chlorine atom, having a weight average molecular weight (Mw) of 1000000 ～ 3500000 and a ratio (Mw/Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) of 3.7 to 6.5 in an absolute molecular weight and an absolute molecular weight distribution measured by GPC-MALS method, having a methyl ethyl ketone insoluble content of 50 wt% or less, an ash content of 0.2 wt% or less, and a total amount of sodium, magnesium, calcium, phosphorus and sulfur in ash of 50 wt% or more, and are highly balanced in roll processability, brix processability, water resistance, compression set resistance and normal physical properties including strength characteristics, and also excellent in crosslinking property and storage stability.
[ particle size of resulting hydrous pellets ]
The proportion of the amount of the aqueous pellets produced in the coagulation step of examples 1 to 2, reference examples 1 to 7 and comparative example 1 to the total amount of the aqueous pellets was measured by using JIS sieves (1) at 710 μm to 6.7mm (not passing through 710 μm but passing through 6.7 mm), (2) at 710 μm to 4.75mm (not passing through 710 μm but passing through 4.75 mm), (3) at 710 μm to 3.35mm (not passing through 710 μm but passing through 3.35 mm). The results are shown below.
Example 1: (1) 90 wt%, (2) 90 wt%, (3) 87 wt%
Example 2: (1) 92 wt%, (2) 91 wt%, and (3) 89 wt%
Reference example 1: (1) 89 wt%, (2) 87 wt%, and (3) 83 wt%
Reference example 2: (1) 91 wt%, (2) 90 wt%, and (3) 83 wt%
Reference example 3: (1) 93 wt%, (2) 91 wt%, and (3) 89 wt%
Reference example 4: (1) 95 wt%, (2) 89 wt%, and (3) 80 wt%
Reference example 5: (1) 92 wt%, (2) 92 wt%, (3) 88 wt%
Reference example 6: (1) 94 wt%, (2) 93 wt%, (3) 87 wt%
Reference example 7: (1) 90 wt%, (2) 89 wt%, and (3) 88 wt%
Comparative example 1: (1) 15 wt%, (2) 1 wt%, (3) 0 wt%
From this result, it was found that even when the same washing was performed, the amount of ash remaining in the acrylic rubber bag was different depending on the size of the aqueous aggregates generated in the coagulation step, and that the washing efficiency of the aqueous aggregates having a large specific ratio of (1) to (3) was high, the ash amount was reduced, and the water resistance was excellent (comparison between reference examples 1 to 7 and comparative example 1 of tables 2-2). Further, it was found that the ash removal rate at the time of dehydration of 20 wt% was also high even when the specific proportions of (1) to (3) were large, the ash amount was further reduced, and the water resistance of the acrylic rubber bag was significantly improved (comparison of examples 1 to 2 with reference examples 1 to 7). It is also clear from a comparison of reference example 6 and reference example 7 that the particle size of the aqueous pellets produced in the coagulation step is independent of the presence or absence of the chain transfer agent.
For reference, the procedure was carried out in the same manner as in comparative example 1 (reference example 9) except that the emulsion polymerization liquid was added to the coagulation liquid in the coagulation step (reference example 8), and the coagulant concentration of the coagulation liquid was changed from 0.7% by weight to 2% by weight, except that the particle size ratio of the produced aqueous pellets and the ash content in the acrylic rubber were measured in the same manner as in comparative example 1. The results are shown below. When the stirring number of the solidification liquid in reference example 9 was changed to 600rpm and the circumferential speed was increased from 0.5m/s to 3.1m/s, the same conditions as in reference example 7 were employed.
Reference example 8: (1) 90 wt%, (2) 55 wt%, and (3) 22 wt%, and ash content 0.55 wt%
Reference example 9: 91 wt%, 70 wt%, 40 wt% and 0.41 wt% ash
From the results, it was found that the water resistance (examples 1 to 2) can be significantly improved by increasing the concentration of the coagulating liquid (2%) in the acrylic rubber bag during the coagulation reaction, changing the method to a method in which the emulsion polymerization liquid is added to the stirred coagulating liquid (Lx ∈) and the coagulating liquid is vigorously stirred (stirring number 600 rpm/circumferential speed 3.1 m/s), whereby the particle size of the produced aqueous pellets can be concentrated in a specific range of 710 μm to 4.75mm, the washing efficiency in hot water and the removal efficiency of the emulsifier and coagulant during dehydration can be significantly improved, the ash content in the acrylic rubber bag can be reduced, and the properties such as the crosslinking property, the roll workability, the compression set resistance and the normal physical properties including the strength property of the acrylic rubber bag can be not impaired.
Example 3
An acrylic rubber bag (M) was obtained in the same manner as in example 2 except that the monomer components were changed to 74.5 parts of ethyl acrylate, 17 parts of n-butyl acrylate, 7 parts of methoxyethyl acrylate, 1.5 parts of mono-n-butyl fumarate and 1.8 parts of sodium tridecyloxy hexaoxyethylene phosphate as shown in Table 3-1, and the properties were evaluated, and the results are shown in Table 3-2. In addition, table 3-1 shows the post-dewatering (draining) water content, maximum torque, specific power, specific energy consumption, shear rate, and shear viscosity of the screw type biaxial extrusion dryer.
Example 4
An acrylic rubber bag (N) was obtained in the same manner as in example 1 except that the monomer components were changed to 74.5 parts of ethyl acrylate, 17 parts of N-butyl acrylate, 7 parts of methoxyethyl acrylate and 1.5 parts of mono-N-butyl fumarate, and the emulsifier was changed to 1.8 parts of sodium tridecyloxy hexaoxyethylene phosphate, and the properties were evaluated, and the results are shown in tables 3 to 2. In addition, table 3-1 shows the post-dewatering (draining) water content, maximum torque, specific power, specific energy consumption, shear rate, and shear viscosity of the screw type biaxial extrusion dryer.
Example 5
An acrylic rubber bag (O) was obtained in the same manner as in example 3 except that the monomer components were changed to 28 parts of ethyl acrylate, 38 parts of N-butyl acrylate, 27 parts of methoxyethyl acrylate, 5 parts of acrylonitrile and 2 parts of allyl glycidyl ether, and the operating conditions of the screw-type biaxial extrusion dryer were changed to high shear (maximum torque 45n·m), and the properties (the compounding agent was changed to "compounding 3"), and the results were shown in table 3-2. In addition, table 3-1 shows the post-dewatering (draining) water content, maximum torque, specific power, specific energy consumption, shear rate, and shear viscosity of the screw type biaxial extrusion dryer.
Example 6
An acrylic rubber bag (P) was obtained in the same manner as in example 5 except that the monomer components were changed to 48.5 parts of ethyl acrylate, 50 parts of n-butyl acrylate and 1.5 parts of mono-n-butyl fumarate, and each characteristic (the compounding agent was changed to "compounding 1") was evaluated, and the results thereof are shown in table 3-2. In addition, table 3-1 shows the post-dewatering (draining) water content, maximum torque, specific power, specific energy consumption, shear rate, and shear viscosity of the screw type biaxial extrusion dryer.
Example 7
An acrylic rubber bag (Q) was obtained in the same manner as in example 5 except that the monomer components were changed to 48.25 parts of ethyl acrylate, 50 parts of n-butyl acrylate and 1.75 parts of mono-n-butyl fumarate, and each characteristic (the compounding agent was changed to "compounding 2") was evaluated, and the results are shown in table 3-2. In addition, table 3-1 shows the post-dewatering (draining) water content, maximum torque, specific power, specific energy consumption, shear rate, and shear viscosity of the screw type biaxial extrusion dryer.
Example 8
An acrylic rubber bag (R) was obtained in the same manner as in example 4 except that the monomer components were changed to 28 parts of ethyl acrylate, 38 parts of N-butyl acrylate, 27 parts of methoxyethyl acrylate, 5 parts of acrylonitrile and 2 parts of allyl glycidyl ether, and the operating conditions of the screw-type biaxial extrusion dryer were changed to high shear (maximum torque 45n·m), and the properties (the compounding agent was changed to "compounding 3"), and the results were shown in table 3-2. In addition, table 3-1 shows the post-dewatering (draining) water content, maximum torque, specific power, specific energy consumption, shear rate, and shear viscosity of the screw type biaxial extrusion dryer.
Example 9
An acrylic rubber bag (S) was obtained in the same manner as in example 8 except that the monomer components were changed to 48.5 parts of ethyl acrylate, 50 parts of n-butyl acrylate and 1.5 parts of mono-n-butyl fumarate, and each characteristic (the compounding agent was changed to "compounding 1") was evaluated, and the results thereof are shown in Table 3-2. In addition, table 3-1 shows the post-dewatering (draining) water content, maximum torque, specific power, specific energy consumption, shear rate, and shear viscosity of the screw type biaxial extrusion dryer.
Example 10
An acrylic rubber bag (T) was obtained in the same manner as in example 8 except that the monomer components were changed to 48.25 parts of ethyl acrylate, 50 parts of n-butyl acrylate and 1.75 parts of mono-n-butyl fumarate, and each characteristic (the compounding agent was changed to "compounding 2") was evaluated, and the results are shown in table 3-2. In addition, table 3-1 shows the post-dewatering (draining) water content, maximum torque, specific power, specific energy consumption, shear rate, and shear viscosity of the screw type biaxial extrusion dryer.
[ Table 3-1]
Figure BDA0004113517400000781
[ Table 3-2]
Figure BDA0004113517400000791
As is clear from tables 3-1 and 3-2, by increasing the maximum torque of the screw type biaxial extrusion dryer to a specific region (high shear) and dehydrating and drying the aqueous pellets, the properties of the acrylic rubber bag of the present invention such as crosslinking property, banbury workability, water resistance, compression set resistance and strength properties were not impaired, and the roll processability was significantly improved (comparison of examples 3 to 4 with examples 5 to 10). It is found that the acrylic rubber comprising a high molecular weight component and a low molecular weight component, which is emulsion polymerized by adding a chain transfer agent, is dried by applying shear at high shear using a screw type biaxial extrusion dryer, whereby the molecular weight distribution can be further appropriately enlarged, and the roll processability can be further improved. On the other hand, although not shown in tables 3-1 and 3-2, it is found that when chain transfer agent is excessively added to excessively expand the molecular weight distribution (Mw/Mn), for example, to 10 or more, the low molecular weight component of the acrylic rubber becomes excessive, and the strength characteristics and compression set resistance are poor, which is not preferable.
Further, the deviation of the amount of methyl ethyl ketone insoluble component was evaluated for each rubber sample by the method described above. Specifically, the amount of methyl ethyl ketone insoluble component at 20 points selected arbitrarily from 20 parts (20 kg) of the rubber sample was measured, and the deviation evaluation of the amount of methyl ethyl ketone insoluble component of the rubber sample was performed based on the above criteria.
When the acrylic rubber packs (a) to (B) and (M) to (T) obtained in examples 1 to 10 and the pellet-like acrylic rubber (J) obtained in comparative example 1 as rubber samples were evaluated for the deviation of the amount of methyl ethyl ketone insoluble components, the results of the acrylic rubber packs (a) to (B) and (M) to (T) in examples 1 to 10 of the present invention were all "excellent", and the result of the pellet-like acrylic rubber (J) of comparative example 1 was "x".
From this, it is assumed that the acrylic rubber bags (a) to (B) and (M) to (T) are melt-kneaded by a screw type biaxial extrusion dryer, and melt-kneaded and dried in a state where substantially no moisture is present (the moisture content is less than 1 wt%), whereby the amount of the methyl ethyl ketone insoluble component is almost eliminated, and the deviation of the amount of the methyl ethyl ketone insoluble component is almost eliminated, whereby the crosslinking property, the roll processability, the compression set resistance and the normal physical properties including the strength characteristics are not impaired, and the banbury processability can be remarkably improved.
On the other hand, it was found that the aqueous pellets produced after emulsion polymerization and coagulation washing under the conditions for producing the acrylic rubber (J) of comparative example 1 were fed into a screw type biaxial extrusion dryer under the same conditions as in example 1 and extrusion-dried, and the methyl ethyl ketone insoluble content deviation measured on the obtained acrylic rubber were substantially the same as those of the acrylic rubber bag (a), and the banbury processability was improved, but the roll processability was evaluated as "x".
Regarding the acrylic rubber compositions comprising the acrylic rubber packages (a) to (B) and (M) to (T) of examples 1 to 10, the mooney scorch storage stability was evaluated according to the following criteria by the method of the processing stability evaluation of mooney scorch inhibition described above, by measuring the mooney scorch time T5 (min) at a temperature of 125 ℃ in accordance with JIS K6300. The results were excellent.
And (3) the following materials: the Mooney scorch time t5 is more than 2.0 minutes
And (2) the following steps: the Mooney scorch time t5 is 1.5 to 2.0 minutes
X: the Mooney scorch time t5 is less than 1.5 minutes
In the acrylic rubber packages (a) to (B) and (M) to (T), the cooling rate of the sheet-like dry rubber extruded from the screw type biaxial extrusion dryer was as high as that of example 1, and was approximately 200 ℃/hour, and was 40 ℃/hour or more.
[ Release to Metal mold ]
The rubber compositions of the acrylic rubber packages (a) to (B) and (M) to (T) obtained in examples 1 to 10 were press-fitted into a 10mm Φx200 mm mold, crosslinked at a mold temperature of 165 ℃ for 2 minutes, and then the rubber crosslinked product was taken out, and mold releasability was evaluated on the basis of the following criteria, and at this time, the acrylic rubber packages (a) to (B) and (M) to (T) were all "excellent", i.e., good evaluation.
And (3) the following materials: can be easily released from the metal mold without mold residue
O: the mold can be easily released from the mold, but it was confirmed that there was little mold residue
Delta: can be easily released from a metal mold, but has a small amount of mold residues
X: difficult to release from a metal mold
Description of the reference numerals
1: acrylic rubber manufacturing system
3: coagulation device
4: cleaning device
5: screw extruder
6: cooling device
7: glue packaging device

Claims (42)

1. An acrylic rubber bag composed of an acrylic rubber having at least one reactive group selected from the group consisting of a carboxyl group, an epoxy group and a chlorine atom,
the weight average molecular weight (Mw) of the acrylic rubber is 1000000 ～ 3500000, the ratio (Mw/Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) is 3.7 to 6.5 based on the absolute molecular weight and the absolute molecular weight distribution measured by GPC-MALS method,
The amount of the insoluble methyl ethyl ketone component in the acrylic rubber bag is 50 wt% or less, the amount of the ash component is 0.2 wt% or less, and the total amount of sodium, magnesium, calcium, phosphorus and sulfur in the ash is 50 wt% or more.
2. The acrylic rubber bag of claim 1, wherein the reactive group is an ion-reactive group.
3. The acrylic rubber bag according to claim 1 or 2, wherein the acrylic rubber is composed of a binding unit derived from a (meth) acrylic acid ester, a binding unit derived from a monomer having a reactive group, and a binding unit derived from another monomer used as needed,
the (meth) acrylic acid ester is at least one selected from the group consisting of alkyl (meth) acrylates and alkoxyalkyl (meth) acrylates,
the reactive group is selected from at least one of carboxyl, epoxy and chlorine atoms.
4. The acrylic rubber bag according to any one of claims 1 to 3, wherein the amount of methyl ethyl ketone insoluble component of the acrylic rubber bag is 15% by weight or less.
5. The acrylic rubber bag according to any one of claims 1 to 4, wherein the values when the amount of the insoluble component of methyl ethyl ketone at 20 points is measured are all within the range of (average ± 5% by weight).
6. The acrylic rubber bag according to any one of claims 1 to 5, wherein the specific gravity of the acrylic rubber bag is 0.9 or more.
7. The acrylic rubber bag according to any one of claims 1 to 6, wherein the pH of the acrylic rubber bag is 6 or less.
8. The acrylic rubber bag according to any one of claims 1 to 7, wherein the acrylic rubber bag is emulsion-polymerized using a phosphate salt or a sulfate salt as an emulsifier.
9. The acrylic rubber bag according to any one of claims 1 to 8, wherein the acrylic rubber bag is obtained by solidifying and drying the emulsion-polymerized polymerization liquid using an alkali metal salt or a group 2 metal salt of the periodic table as a coagulant.
10. The acrylic rubber bag according to any one of claims 1 to 9, wherein the acrylic rubber bag is melt-kneaded and dried after solidification.
11. The acrylic rubber bag according to claim 10, wherein the melt-kneading and drying are performed in a state substantially free of moisture.
12. The acrylic rubber bag according to claim 10 or 11, wherein the melt-kneading and drying are performed under reduced pressure.
13. The acrylic rubber bag according to any one of claims 10 to 12, wherein cooling is performed at a cooling rate of 40 ℃/hr or more in the melt kneading and drying.
14. The acrylic rubber bag according to any one of claims 1 to 13, wherein the acrylic rubber bag is obtained by washing, dehydrating and drying an aqueous pellet having a particle diameter in the range of 710 μm to 6.7mm in a proportion of 50% by weight or more.
15. The manufacturing method of the acrylic rubber bag comprises the following steps:
an emulsifying step of emulsifying a monomer component with water and an emulsifier, wherein the monomer component contains a (meth) acrylate, a monomer containing a reactive group, and optionally another copolymerizable monomer, the (meth) acrylate is at least one selected from alkyl (meth) acrylates and alkoxyalkyl (meth) acrylates, and the reactive group is at least one selected from carboxyl groups, epoxy groups, and chlorine atoms;
an emulsion polymerization step of initiating emulsion polymerization in the presence of a redox catalyst comprising an inorganic radical generator and a reducing agent, adding a chain transfer agent and a reducing agent in batch during the polymerization, and continuing the emulsion polymerization until the polymerization conversion becomes 90 wt% or more to obtain an emulsion polymerization solution;
A coagulation step of adding the emulsion polymerization liquid obtained to the stirred coagulation liquid to coagulate, thereby producing water-containing pellets;
a washing step of washing the produced hydrous pellets with hot water;
a dehydration-drying-molding step of dehydrating the washed aqueous pellets with a dehydration barrel to a water content of 1 to 40 wt% and drying with a dryer barrel to a water content of less than 1 wt%, using a dehydration barrel having a dehydration slit, a dryer barrel under reduced pressure, and a screw type biaxial extrusion dryer having a die at the tip end, and extruding a sheet-like dried rubber from the die; and
and a step of packaging the extruded sheet-like dry rubber, wherein the sheet-like dry rubber is cut and laminated.
16. The method for producing an acrylic rubber bag according to claim 15, wherein the method for producing an acrylic rubber bag produces the acrylic rubber bag according to any one of claims 1 to 14.
17. The method for producing an acrylic rubber bag according to claim 15 or 16, wherein in the emulsion polymerization step, emulsion polymerization is performed using a phosphate salt or a sulfate salt as an emulsifier.
18. The method for producing an acrylic rubber bag according to any one of claims 15 to 17, wherein the polymerization liquid produced in the emulsion polymerization step is coagulated and dried by using an alkali metal salt or a group 2 metal salt of the periodic table as a coagulant.
19. The method for producing an acrylic rubber bag as claimed in claim 18, wherein the polymerization liquid produced in the emulsion polymerization step is coagulated by adding the polymerization liquid to an aqueous solution containing a coagulant and stirring,
the coagulant comprises an alkali metal salt or a group 2 metal salt of the periodic table of elements.
20. The method for producing an acrylic rubber bag according to any one of claims 15 to 19, wherein the polymerization liquid produced in the emulsion polymerization step is brought into contact with a coagulant to be coagulated, and then melt kneaded and dried.
21. The method for producing an acrylic rubber bag according to claim 20, wherein the melt kneading and drying are performed in a state substantially free of moisture.
22. The method for producing an acrylic rubber bag according to claim 20 or 21, wherein the melt-kneading and drying are performed under reduced pressure.
23. The method for producing an acrylic rubber bag according to any one of claims 20 to 22, wherein the acrylic rubber after melt-kneading and drying is cooled at a cooling rate of 40 ℃/hr or more.
24. The method for producing an acrylic rubber bag according to any one of claims 15 to 23, wherein the aqueous pellets having a particle diameter in the range of 710 μm to 6.7mm in a proportion of 50% by weight or more are washed, dehydrated and dried.
25. A rubber composition comprising a crosslinking agent, a filler, and a rubber component containing the acrylic rubber bag according to any one of claims 1 to 14.
26. The rubber composition according to claim 25, wherein the filler is a reinforcing filler.
27. The rubber composition according to claim 25, wherein the filler is a carbon black.
28. The rubber composition according to claim 25, wherein the filler is a silica type.
29. The rubber composition according to any one of claims 25 to 28, wherein the crosslinking agent is an organic crosslinking agent.
30. The rubber composition according to any one of claims 25 to 29, wherein the crosslinking agent is a multi-component compound.
31. The rubber composition according to any one of claims 25 to 30, wherein the crosslinking agent is an ion-crosslinkable compound.
32. The rubber composition according to claim 31, wherein the crosslinking agent is an ion-crosslinkable organic compound.
33. The rubber composition according to claim 31 or 32, wherein the crosslinking agent is a polyionic organic compound.
34. The rubber composition according to any one of claims 31 to 33, wherein the ion of the ion-crosslinkable compound, the ion-crosslinkable organic compound or the polyion-organic compound as the crosslinking agent is at least one ion-reactive group selected from the group consisting of an amino group, an epoxy group, a carboxyl group and a thiol group.
35. The rubber composition according to claim 33, wherein the crosslinking agent is at least one polyionic compound selected from the group consisting of a polyamine compound, a polyepoxide compound, a polycarboxylic acid compound and a polythiol compound.
36. The rubber composition according to any one of claims 25 to 35, wherein the content of the crosslinking agent is in the range of 0.001 to 20 parts by weight relative to 100 parts by weight of the rubber component.
37. The rubber composition of any of claims 25-36, wherein the rubber composition further comprises an anti-aging agent.
38. The rubber composition according to claim 37, wherein the anti-aging agent is an amine-based anti-aging agent.
39. A process for producing a rubber composition comprising mixing the rubber component comprising the acrylic rubber bag according to any one of claims 1 to 14, a filler and an optionally used antioxidant, and then mixing the resulting mixture with a crosslinking agent.
40. A rubber crosslinked product obtained by crosslinking the rubber composition according to any one of claims 25 to 38.
41. A rubber crosslinked according to claim 40 wherein the crosslinking of the rubber composition is performed after molding.
42. The rubber crosslinked according to claim 40 or 41 wherein the crosslinking of the rubber composition is a crosslinking that performs primary crosslinking and secondary crosslinking.
CN202180058024.0A 2020-06-05 2021-06-04 Acrylic rubber bag excellent in roll processability, banbury processability, water resistance, strength characteristics and compression set resistance Pending CN116057076A (en)

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