CN116063770A - Polyethylene composition, preparation method and application thereof, and polyolefin microporous breathable film - Google Patents

Polyethylene composition, preparation method and application thereof, and polyolefin microporous breathable film Download PDF

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CN116063770A
CN116063770A CN202111273490.9A CN202111273490A CN116063770A CN 116063770 A CN116063770 A CN 116063770A CN 202111273490 A CN202111273490 A CN 202111273490A CN 116063770 A CN116063770 A CN 116063770A
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polyethylene
polyethylene composition
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张雅茹
宋文波
刘振杰
初立秋
张晓萌
李娟�
李�杰
康鹏
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Sinopec Beijing Research Institute of Chemical Industry
China Petroleum and Chemical Corp
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Sinopec Beijing Research Institute of Chemical Industry
China Petroleum and Chemical Corp
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Priority to CA3236535A priority patent/CA3236535A1/en
Priority to AU2022374330A priority patent/AU2022374330A1/en
Priority to PCT/CN2022/128276 priority patent/WO2023072254A1/en
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    • C08J9/00—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof
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    • C08J2423/00—Characterised by the use of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Derivatives of such polymers
    • C08J2423/02—Characterised by the use of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Derivatives of such polymers not modified by chemical after treatment
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    • C08J2423/06—Polyethene

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Abstract

The invention relates to the field of polyolefin compositions, and discloses a polyolefin composition, a preparation method and application thereof. The composition comprises 100 parts by weight of polyethylene, 20-110 parts by weight of pore-forming agent and 0.1-2.5 parts by weight of antioxidant compound auxiliary agent; the pore-forming agent is maleic anhydride copolymer microsphere with a cross-linked structure, the cross-linking degree of the copolymer microsphere is more than or equal to 65%, and the average particle size is 500-2000nm. The composition contains maleic anhydride copolymer microsphere with a cross-linked structure as an organic pore-forming agent, the particle size of the pore-forming agent is uniformly distributed, the dispersion in a polyethylene matrix is good and no agglomeration phenomenon occurs under the condition that a coupling agent and a dispersing agent are not used, and the defects of uneven pore size distribution, poor dispersion, poor compatibility and the like caused by an inorganic pore-forming agent can be avoided. The composition can be applied to a breathable film to improve the breathable uniformity of the product.

Description

Polyethylene composition, preparation method and application thereof, and polyolefin microporous breathable film
Technical Field
The invention relates to the field of polyolefin compositions, in particular to a polyolefin composition, a preparation method and application thereof and a polyolefin microporous breathable film.
Background
The breathable film is also called as a 'water-blocking breathable microporous film', and has the characteristics of ventilation and water impermeability. A composite material is prepared from thermoplastic plastics as matrix, and solid particles (such as calcium carbonate, barium sulfate, titanium oxide and talc powder) through blowing, rolling or casting to obtain film, and uniaxial or biaxial stretching under proper conditions to obtain microporous film. The microporous breathable film can allow gases such as water vapor, air and the like to pass through, can block liquid, can be widely applied to medical articles such as medical protective clothing, wound nursing bandages, dressings and the like, sanitary articles such as baby diapers, adult nursing products and the like, and the fields such as food packaging, daily products and the like, and is a new material which is rapidly developed in the last twenty years.
In theory, thermoplastics could be the matrix resin for the breathable film material, but polyethylene breathable films have the greatest ratio from the point of view of the overall market value of microporous breathable films. Polyethylene has the advantages of rich raw material sources, easy processing and forming, good film forming effect, comfortable and soft hand feeling and the like, and is widely used for matrix resins of breathable film materials.
The hygiene industry is the largest end market for polyethylene breathable films, and therefore the safety and comfort of the breathable film must be considered, and therefore, considerable quality requirements are placed on the porogens used in the preparation of the polyethylene breathable films. Inorganic filler, especially calcium carbonate, is the preferred material for pore-forming agent due to its abundant resources, low cost and good comprehensive properties. However, the inorganic pore-forming agent has the advantages of hydrophilic and oleophobic surface, extremely strong polarity, poor compatibility with a polymer matrix and difficult uniform dispersion in the matrix. Meanwhile, the dispersion uniformity of the pore-forming agent in the matrix can influence the mechanical property, the surface flatness, the pore diameter uniformity of micropores, the porosity and other parameters of the breathable film. In the traditional production process, the inorganic filler is pretreated by adopting a surfactant, so that the compatibility of the inorganic filler and a matrix is improved, and meanwhile, the dispersing problem of the inorganic filler is solved by adding a coupling agent and a dispersing agent.
CN102336940a discloses a composition of a breathable film with low air permeability and a preparation method thereof, and the composition comprises a polyolefin resin mixture, an air permeability regulator, surface modified micron-sized inorganic particles, an antioxidant, a lubricant and a coupling agent, and has the advantages that the micron-sized inorganic filler can improve the mechanical property of the breathable film, and meanwhile, the surface of the inorganic particles is coupled and modified to increase the compatibility with the polyolefin resin, but the disadvantage that the micron-sized inorganic particles cannot be uniformly dispersed in matrix resin, thereby affecting the air permeability uniformity of the film.
The CN1176986C discloses a preparation method of a special resin for polyolefin high-air-permeability casting film, which is prepared by taking polyolefin resin (three compounds of LDPE, LLDPE and copolymerized PP) and superfine mineral filler (calcium carbonate, talcum powder and the like with the particle size of 3-10 mu m) as main raw materials, adding a Ti-Al composite coupling agent, a POE modifier and an OPE dispersing agent, and carrying out coupling treatment, compatibilization dispersion, banburying and extrusion granulation. The special resin is prepared through casting and stretching processes, so that uniform and fine pores are generated between mineral filler particles and polyolefin in the film, and the polyolefin high-permeability casting film is formed after cooling and crystallization. The method can not effectively form holes and control the aperture, and an internal mixer is used, so that the process is complicated.
CN101747548A discloses a composite and a method for preparing a high strength polyolefin breathable film, the components comprising: polyolefin resin, micron-sized and nano-sized inorganic filler, antioxidant, processing aid and coupling agent. Wherein the nano inorganic filler can improve the mechanical property of the polyolefin breathable film, reduce the thickness of the breathable film, and can prepare the breathable film with high strength and high air permeability by adjusting the process conditions; however, the poor compatibility of the nano inorganic filler and the polyolefin resin can cause non-uniformity of ventilation of the material, thereby affecting the use of the breathable film.
At present, the following problems exist with inorganic porogens used in the market for producing breathable films: (1) easy agglomeration; (2) The pore diameter uniformity of the breathable film is poor due to the large particle size and the non-uniformity of the particle size distribution, and even a large number of pinhole defects occur; (3) The surface modification effect of the filler particles is poor, and the compatibility with a matrix is poor, so that the strength of the film is affected; (4) The filler particles have poor dispersibility and migrate to the surface of the breathable film, so that the breathable film has color differences or color spots.
Disclosure of Invention
In order to overcome the problems in the prior art, the invention provides a polyethylene composition, a preparation method and application thereof and a polyolefin microporous breathable film. The composition contains crosslinked maleic anhydride copolymer microsphere as organic pore-forming agent, and the pore-forming agent has uniform particle size distribution, can be well dispersed in polyethylene matrix without using coupling agent or dispersing agent, has no agglomeration phenomenon, and can avoid the defects of uneven pore size distribution, poor dispersibility, poor compatibility and the like caused by inorganic pore-forming agent. The composition can be applied to a breathable film to improve the breathable uniformity of the product.
In order to achieve the above object, the first aspect of the present invention provides a polyethylene composition, characterized in that the composition comprises 100 parts by weight of polyethylene, 20 to 110 parts by weight of a pore-forming agent and 0.1 to 2.5 parts by weight of an antioxidant compounding aid;
the pore-forming agent is cross-linked maleic anhydride copolymer microsphere, the cross-linking degree of the copolymer microsphere is more than or equal to 65%, and the average particle size is 500-2000nm.
In a second aspect, the invention provides the use of the above polyethylene composition in a polyolefin microporous breathable film.
A third aspect of the present invention provides a process for producing the above polyethylene composition, characterized in that the process comprises:
(1) Mixing polyethylene, a pore-forming agent and an antioxidant composite auxiliary agent to obtain a mixture;
(2) And carrying out melt blending extrusion, granulating and drying on the mixture in a double-screw extruder to obtain the polyethylene composition.
According to a fourth aspect of the present invention, there is provided a microporous breathable film of polyolefin, characterized in that said microporous breathable film is produced from the above polyethylene composition.
Through the technical scheme, the polyethylene composition provided by the invention, the preparation method and application thereof, and the polyolefin microporous breathable film have the following beneficial effects:
The composition provided by the invention is added with the crosslinked maleic anhydride copolymer microsphere as the pore-forming agent, the copolymer microsphere has uniform particle size distribution, and the uniform dispersion of the pore-forming agent in the polyethylene blend matrix and the uniform pore size of micropores can be realized under the condition that a coupling agent and a dispersing agent are not used; the method can solve the problems of small adjustable range of physical properties and air permeability of the air permeable membrane in the prior art, and has the advantages of wide adaptability, simple operation and stable product performance.
The polyethylene composition provided by the invention can be widely applied to the fields of disposable medical and health products, water-blocking and moisture-permeable materials and the like.
Drawings
FIG. 1 is a SEM photograph of a cross-section of a sample of the polyethylene composition prepared in example 1;
FIG. 2 is a SEM photograph of a cross-section of a sample of the polyethylene composition prepared in example 2;
FIG. 3 is a SEM photograph of a cross-section of a polyethylene composition-sheet prepared in example 3;
FIG. 4 is a SEM photograph of a cross-section of a polyethylene composition-sheet prepared in example 5;
FIG. 5 is an SEM photograph of a cross-section of a sample of the polyethylene composition prepared in comparative example 1;
FIG. 6 is an SEM photograph of a cross-section of a sample of the polyethylene composition prepared in comparative example 2;
FIG. 7 is an SEM photograph of a cross-section of a polyethylene composition-sheet prepared in comparative example 3.
Detailed Description
The endpoints and any values of the ranges disclosed herein are not limited to the precise range or value, and are understood to encompass values approaching those ranges or values. For numerical ranges, one or more new numerical ranges may be found between the endpoints of each range, between the endpoint of each range and the individual point value, and between the individual point value, in combination with each other, and are to be considered as specifically disclosed herein.
The first aspect of the invention provides a polyethylene composition, which is characterized by comprising 100 parts by weight of polyethylene, 20-110 parts by weight of pore-forming agent and 0.1-2.5 parts by weight of antioxidant composite additive;
the pore-forming agent is cross-linked maleic anhydride copolymer microsphere, the cross-linking degree of the copolymer microsphere is more than or equal to 65%, and the average particle size is 500-2000nm.
The composition provided by the invention is added with the crosslinked maleic anhydride copolymer microsphere as the pore-forming agent, the copolymer microsphere has uniform particle size distribution, and the uniform dispersion of the pore-forming agent in the polyethylene blend matrix and the uniform pore size of micropores can be realized under the condition that a coupling agent and a dispersing agent are not used; the method can solve the problems of small adjustable range of physical properties and air permeability of the air permeable membrane in the prior art, and has the advantages of wide adaptability, simple operation and stable product performance.
Further, the composition comprises 100 parts by weight of polyethylene, 30-90 parts by weight of pore-forming agent and 0.2-1.5 parts by weight of antioxidant compound auxiliary agent.
Further, the crosslinking degree of the copolymer microsphere is more than or equal to 70%, and the average particle size is 800-1700nm.
Further, the average particle diameter of the copolymer microsphere is 900-1500nm.
According to the invention, the polyethylene has a melting enthalpy of DeltaH mPE The polyethylene composition has a melting enthalpy of DeltaH m composition ；
Wherein DeltaH mPE And DeltaH m composition The difference is 8-48J/g.
In the present invention, when the difference between the melting enthalpy of the polyethylene and the melting enthalpy of the polyethylene composition satisfies the above range, it can be shown that the crosslinked maleic anhydride copolymer microspheres are uniformly distributed in the polyethylene composition, and a phenomenon that the melting enthalpy of the composition is greatly reduced due to the agglomeration of the crosslinked maleic anhydride copolymer microspheres does not occur, thereby enabling the breathable film prepared from the composition to have both excellent physical properties and breathability.
In the present invention, the enthalpy of fusion of the polyethylene and the polyethylene composition is measured by differential scanning calorimetry.
Further, ΔH mPE And DeltaH m composition The difference is 10-45J/g.
According to the invention, the crosslinked maleic anhydride copolymer microsphere copolymer comprises structural units A from maleic anhydride and structural units B from comonomer and crosslinked structural units;
In the copolymer, the molar ratio between the structural unit a, the structural unit B and the crosslinking structural unit is 100:100-120:1-40.
Further, in the copolymer, the molar ratio between the structural unit a, the structural unit B and the crosslinked structure is 100:100-105:10-30.
According to the invention, the comonomer M is selected from at least one of the compounds of formula (I), vinyl acetate, mixed carbon four and mixed carbon five;
Figure BDA0003329487810000061
wherein, in the formula I, R is H or methyl.
In the present invention, the mixed carbon four refers to a generic term of hydrocarbon compounds (mainly including butene) with four carbon atoms, and generally, the mixed carbon four includes a certain amount of alkane (such as n-butane) and other impurities which may exist in addition to butene (such as trans-2-butene, cis-2-butene, n-butene and isobutene) with various structures. In the present invention, the content of the olefin in the mixed carbon four is in the range of 60 to 75 wt%.
In the present invention, the mixed carbon five refers to a generic term for hydrocarbon compounds having five carbon atoms (mainly including pentene), and generally, in addition to pentenes (such as diene (isoprene, cyclopentadiene, 1, 4-pentadiene, piperylene) and mono-olefins (1-pentene, 2-pentene, cyclopentene, 2-methyl-1-butene, 2-methyl-2-butene)) having various structures, a certain amount of alkane (such as n-pentane, isopentane, cyclopentane, 2-methylbutane), alkyne (such as butyne-2, 3-pentene-1 alkyne) and other impurities which may be present are included in the carbon five. In the invention, the content of olefin in the mixed carbon five is 55-65 wt%.
In one specific embodiment of the invention, the porogen is a crosslinked maleic anhydride copolymer microsphere, which is prepared according to the following steps:
in an organic solvent, in the presence of an initiator, contacting and reacting maleic anhydride, a comonomer M shown in a formula (I) and a crosslinking agent to obtain the crosslinked maleic anhydride copolymer microsphere;
the comonomer M is at least one selected from a compound shown in a formula (I), vinyl acetate, mixed carbon four and mixed carbon five;
Figure BDA0003329487810000071
wherein, in the formula I, R is H or methyl.
In one embodiment of the invention, the comonomer M is used in an amount of 50 to 150mol, more preferably 75 to 100mol, relative to 100mol of maleic anhydride.
In the present invention, the amount of the organic solvent is not particularly limited as long as it can provide a medium for the reaction, and is preferably 50 to 150L, more preferably 75 to 100L, relative to 100mol of maleic anhydride.
In the present invention, the organic solvent may be a solvent common to various solution polymerization reactions, for example, the organic solvent includes an organic acid alkyl ester, that is, an organic acid alkyl ester, or a mixture of an organic acid alkyl ester and an alkane, or a mixture of an organic acid alkyl ester and an aromatic hydrocarbon. Wherein the alkyl esters of organic acids include, but are not limited to: at least one of methyl formate, ethyl formate, propyl formate, butyl formate, isobutyl formate, pentyl formate, methyl acetate, ethyl acetate, propyl acetate, butyl acetate, isobutyl acetate, sec-butyl acetate, amyl acetate, isoamyl acetate, benzyl acetate, methyl propionate, ethyl propionate, butyl propionate, methyl butyrate, ethyl butyrate, butyl butyrate, isobutyl butyrate, isoamyl isovalerate, methyl benzoate, ethyl benzoate, propyl benzoate, butyl benzoate, isoamyl benzoate, methyl phenylacetate, and ethyl phenylacetate. The alkanes include, but are not limited to: n-hexane and/or n-heptane. The aromatic hydrocarbons include, but are not limited to: at least one of benzene, toluene and xylene.
In the present invention, the amount of the initiator is not particularly limited, and it is preferable that the amount of the initiator is 0.05 to 10mol, more preferably 1 to 1.5mol, relative to 100mol of maleic anhydride.
In the present invention, the initiator may be a reagent for initiating polymerization of maleic anhydride and α -methylstyrene (or styrene), which is common in the art, and may be a thermal decomposition type initiator. Preferably, the initiator is at least one selected from dibenzoyl peroxide, dicumyl peroxide, di-t-butyl peroxide, lauroyl peroxide, t-butyl peroxybenzoate, diisopropyl peroxydicarbonate, dicyclohexyl peroxydicarbonate, azobisisobutyronitrile and azobisisoheptonitrile.
In the present invention, the amount of the crosslinking agent is not particularly limited, and it is preferably 1 to 40mol, more preferably 10 to 20mol, still more preferably 15 to 20mol, relative to 100mol of maleic anhydride.
In the present invention, the crosslinking agent may be a vinyl-containing monomer capable of undergoing radical polymerization having various common two or more functionalities. Preferably, the crosslinking agent is selected from divinylbenzene and/or acrylic crosslinking agents containing at least two acrylic groups, the structural formula of the acrylic groups is: -O-C (O) -C (R') =ch 2 R' is H or C 1 -C 4 Alkyl (e.g., methyl).
Further, the crosslinking agent is selected from at least one of divinylbenzene, propylene glycol-based bis (meth) acrylate (such as 1, 3-propanediol dimethacrylate, 1, 2-propanediol dimethacrylate, 1, 3-propanediol diacrylate, 1, 2-propanediol diacrylate), ethylene glycol-based bis (meth) acrylate (ethylene glycol dimethacrylate, ethylene glycol diacrylate, diethylene glycol dimethacrylate, diethylene glycol diacrylate, triethylene glycol dimethacrylate, triethylene glycol diacrylate, tetraethylene glycol dimethacrylate, tetraethylene glycol diacrylate), trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, polyethylene glycol diacrylate, polyethylene glycol dimethacrylate, diethylene glycol phthalate diacrylate, pentaerythritol tetraacrylate, pentaerythritol pentaacrylate, pentaerythritol hexaacrylate, and ethoxylated polyfunctional acrylate.
Still further, the crosslinking agent is divinylbenzene.
According to the invention, the reaction conditions include: the reaction is carried out in the presence of inert atmosphere, the reaction temperature is 50-90 ℃, the reaction time is 3-15h, and the reaction pressure is 0.1-1MPa.
Further, the reaction temperature is 60-70 ℃, the reaction time is 5-12h, and the reaction pressure is 0.1-0.5MPa.
In the invention, the product (suspension) of the reaction is subjected to post-treatment steps such as separation, washing, drying and the like to obtain the crosslinked maleic anhydride copolymer microsphere.
In the present invention, a water bath and/or an oil bath is used to provide the heat required for the polymerization of the present invention.
In the invention, a solid-liquid separation mode is adopted to separate the copolymer emulsion suspension obtained by the polymerization reaction so as to obtain the composite microsphere.
In the present invention, a solid-liquid separation method which is conventional in the prior art, preferably, a centrifugal separation method can be used.
In the invention, when centrifugal separation is adopted, the centrifugal rotating speed is 1500-5000rad/min, and the centrifugal time is 5-60min.
According to the invention, the polyethylenes are linear low density polyethylenes and low density polyethylenes.
According to the invention, the linear low density polyethylene is used in an amount of 60 to 99 parts by weight, preferably 70 to 95 parts by weight, based on 100 parts by weight of polyethylene; the low density polyethylene is used in an amount of 1 to 40 parts by weight, preferably 5 to 30 parts by weight.
According to the invention, the linear low density polyethylene is a copolymer of ethylene and an alpha-olefin; preferably, the alpha-olefin is selected from at least one of butene, hexene and octene.
In the invention, the linear low density polyethylene is prepared by Ziegler Natta catalyst and/or metallocene catalyst.
According to the invention, the linear low density polyethylene has a density of 0.905g/cm 3 -0.935g/cm 3 ；
According to the invention, the linear low density polyethylene has a melt flow rate of 0.5g/10min to 10g/10min, preferably 2g/10min to 6g/10min, at 190℃and under a load of 2.16 kg.
According to the invention, the linear low density polyethylene has a molecular weight distribution of 2 to 12, preferably 2 to 10.
According to the invention, the density of the low density polyethylene is 0.913g/cm 3 -0.934g/cm 3 。
According to the invention, the melt flow rate of the low density polyethylene at 190℃and 2.16kg load is from 0.1g/10min to 12g/10min, preferably from 2g/10min to 9g/10min.
According to the invention, the molecular weight distribution of the low density polyethylene is 5 to 11, preferably 6 to 10.
According to the present invention, the polyethylene composition further comprises at least one selected from the group consisting of: medium Density Polyethylene (MDPE), high Density Polyethylene (HDPE), ultra low density polyethylene (VLDPE), ultra high molecular weight polyethylene (hmwppe), polypropylene, propylene-based copolymers, ethylene-vinyl acetate copolymers, ethylene methyl acrylate copolymers, polyolefin plastomers, polyolefin elastomers and polybutenes.
According to the invention, the antioxidant composite auxiliary comprises an antioxidant and an acid absorber.
According to the invention, the weight ratio of the antioxidant to the acid absorber is 1-6:1, a step of; preferably 2-5:1.
according to the present invention, the antioxidant is at least one selected from the group consisting of pentaerythritol tetrakis [ beta- (3, 5-di-t-butyl-4-hydroxyphenyl) propionate ], phenyl tris (2, 4-di-t-butyl) phosphite, stearyl propionate and alkylated polyphenols.
According to the present invention, the acid absorbing agent is a stearate, preferably at least one selected from the group consisting of calcium stearate, zinc stearate and sodium stearate.
According to the invention, the antioxidant compound auxiliary is a mixture of pentaerythritol tetra (beta- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionate), phosphoric triester of (2, 4-di-tert-butylphenyl) phosphite and calcium stearate, wherein the weight ratio of the pentaerythritol tetra (beta- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionate), the phosphoric triester of (2, 4-di-tert-butylphenyl) phosphite to the calcium stearate is (1-3): 1, preferably (1-2): 1.
According to the present invention, the polyethylene composition does not contain a coupling agent and a dispersing agent.
In a second aspect, the invention provides the use of the above polyethylene composition in a polyolefin microporous breathable film.
According to the invention, the polyethylene composition is used for preparing the polyolefin microporous breathable film, so that the physical properties and the air permeability of the breathable film can be obviously improved, and the polyethylene composition can be further used in the fields of disposable medical and health products, water-blocking and moisture-permeable materials and the like.
A third aspect of the present invention provides a process for producing the above polyethylene composition, characterized in that the process comprises:
(1) Mixing polyethylene, a pore-forming agent and an antioxidant composite auxiliary agent to obtain a mixture;
(2) And carrying out melt blending extrusion, granulating and drying on the mixture in a double-screw extruder to obtain the polyethylene composition.
According to the invention, the rotating speed of the double-screw extruder is 150-400r/min; preferably 180-350r/min.
According to the invention, the temperatures of the feeding section, melting section, homogenizing section and die of the twin-screw extruder are 150-180deg.C, 165-200deg.C, 180-215 deg.C, 175-210 deg.C, respectively.
Preferably, the temperatures of the feeding section, melting section, homogenizing section and die of the twin-screw extruder are 160-175 ℃, 175-190 ℃, 190-210 ℃, 180-205 ℃, respectively.
According to a fourth aspect of the present invention, there is provided a microporous breathable film of polyolefin, characterized in that said microporous breathable film is produced from the above polyethylene composition.
In the invention, the polyolefin microporous breathable film prepared from the polyethylene composition not only maintains the excellent physical properties of the polyethylene composition, but also has high air permeability, and can be used in the fields of disposable medical and health products, water-blocking and moisture-permeable materials and the like.
In the present invention, the method for producing the polyolefin microporous breathable film is not particularly limited, and can be produced by selecting an appropriate method according to need, for example: and adding the polyethylene composition into an extrusion casting machine for melting and casting the sheet, wherein the extrusion temperature is 210-240 ℃, and the cooling roller temperature is 20-60 ℃, so as to prepare the polyethylene casting film. The cast film is uniaxially stretched by 2-5 times to obtain the polyethylene microporous breathable film with the average thickness of 25-35 mu m, and the heat setting temperature is 70-120 ℃.
The present invention will be described in detail by examples. It should be understood that the detailed description and specific examples, while indicating and illustrating the invention, are not intended to limit the invention.
The relevant data in the invention and the embodiment thereof are obtained according to the following test method:
1. degree of crosslinking of crosslinked maleic anhydride copolymer: the crosslinking degree is gel content, 2-3 g of polymer microsphere (w 1) is weighed, wrapped by medium-speed qualitative filter paper, put into a Soxhlet extractor, extracted by tetrahydrofuran for 24 hours, and the polymer is dried and weighed for w2, and the crosslinking degree is obtained through calculation of w2/w 1;
2. Content of each structural unit in the copolymer: for the crosslinked maleic anhydride-alpha-methylstyrene copolymer microsphere, LC-MC is adopted to analyze the dosage of monomer or crosslinking agent which does not participate in the reaction, and the molar ratio of the structural unit A, the structural unit B and the crosslinked structural unit is calculated according to the dosage; for the crosslinked mixed carbon tetra-maleic anhydride copolymer microsphere, determining the carbon and oxygen content in the polymer through X-ray fluorescence spectrum analysis; the supernatant after centrifugal separation is analyzed by gas chromatography to determine the content of residual maleic anhydride and crosslinking agent; and the molar ratio between the structural unit A, the structural unit B and the crosslinking structural unit in the polymer can be calculated by comprehensively analyzing the results.
3. Copolymer microsphere particle size test method: performing vacuum metal spraying on the copolymer microsphere powder, performing morphology observation on Hitachi S4800 type field emission scanning electron microscope of Hitachi, selecting 500 microspheres from an electron microscope photograph, measuring the diameters of the microspheres, and calculating the average particle diameter of the microspheres by using a mathematical average method;
4. morphology of cross section of polyethylene composition sample and dispersion of porogen: soaking a sample in liquid nitrogen for 15 minutes, performing brittle fracture, performing metal spraying treatment on the section, and characterizing the section of the material by using a Hitachi S4800 type field emission scanning electron microscope of Hitachi, so as to obtain a microscopic morphology photo;
5. Melt flow rate MFR: measured at 190℃under a load of 2.16kg according to the method specified in GB/T3682-2000;
6. tensile properties: measuring according to the method specified in GB/T1040.3-2006 by adopting a universal tensile machine;
9、T C tm and Δhm: the melting process and crystallization process of the material were analyzed using a differential scanning calorimeter. The specific operation is as follows: under the protection of nitrogen, 5-10mg of sample is measured by adopting a three-section temperature-raising and lowering measuring method from 20 ℃ to 200 ℃, the melting and crystallization process of the material is reflected by the change of heat flow, and the crystallization temperature T is calculated according to GB/T19466.3-2004 C Melting temperature Tm and melting enthalpy DeltaHm.
8. Water Vapor Transmission Rate (WVTR): the measurement was carried out according to the method specified in GB/T12704-1991.
The raw materials used in the examples and comparative examples are all commercially available.
Preparation example 1
Preparation of porogen A1
400g of maleic anhydride, 472g of alpha-methylstyrene, 95g of divinylbenzene and 8g of azobisisobutyronitrile were dissolved in 4L of isoamyl acetate and reacted under nitrogen at 70℃under 0.1MPa for 5 hours. And centrifugally separating the reacted system for 30 minutes under the condition of 5000rad/min by a centrifugal machine to obtain the crosslinked alpha-methylstyrene/maleic anhydride polymer microsphere A1, washing and purifying by normal hexane, and drying in vacuum. Wherein the amount of alpha-methylstyrene was 97.9mol, the amount of divinylbenzene was 17.9mol, and the amount of initiator was 1.2mol, relative to 100mol of maleic anhydride.
The crosslinking degree of the crosslinked maleic anhydride-alpha-methylstyrene copolymer microsphere A1 is 82%, the molar ratio of the structural unit A to the structural unit B to the crosslinked structural unit is 100:101:25, and the average particle size of the copolymer microsphere is 1200nm.
Preparation example 2
Preparation of porogen A2
400g of maleic anhydride, 472g of alpha-methylstyrene, 104g of divinylbenzene and 8g of azobisisobutyronitrile were dissolved in 4L of isoamyl acetate and reacted under nitrogen at 70℃under 0.1MPa for 5 hours. And centrifugally separating the reacted system for 30 minutes under the condition of 5000rad/min by a centrifugal machine to obtain the crosslinked alpha-methylstyrene/maleic anhydride polymer microsphere A2, washing and purifying by normal hexane, and drying in vacuum. Wherein the amount of alpha-methylstyrene was 97.9mol, the amount of divinylbenzene was 19.6mol, and the amount of initiator was 1.2mol, relative to 100mol of maleic anhydride.
The crosslinking degree of the crosslinked maleic anhydride-alpha-methylstyrene copolymer microsphere A1 is 84%, the molar ratio of the structural unit A to the structural unit B to the crosslinked structural unit is 100:101:28, and the average particle size of the copolymer microsphere is 900nm.
Preparation example 3
Preparation of porogen A3
1000g of maleic anhydride, 1200g of alpha-methylstyrene, 200g of divinylbenzene and 20g of azobisisobutyronitrile were dissolved in 10L of isoamyl acetate and reacted under nitrogen at 70℃under 0.1MPa for 5 hours. And centrifugally separating the reacted system for 30 minutes under the condition of 5000rad/min by a centrifugal machine to obtain the crosslinked alpha-methylstyrene/maleic anhydride polymer microsphere A3, washing and purifying by normal hexane, and drying in vacuum. Wherein the amount of alpha-methylstyrene was 99.6mol, the amount of divinylbenzene was 15.1mol, and the amount of initiator was 1.2mol, relative to 100mol of maleic anhydride.
The crosslinking degree of the crosslinked maleic anhydride-alpha-methylstyrene copolymer microsphere A1 is 70%, the molar ratio of the structural unit A to the structural unit B to the crosslinked structural unit is 100:101:23, and the average particle size of the copolymer microsphere is 1500nm.
Preparation example 4
Preparation of porogen A4
The composition of the mixed butene gas is as follows: trans-2-butene, 40.83% by weight; cis-2-butene, 18.18% by weight; n-butane, 24.29 wt%; n-butene, 9.52 wt%; 2.78% by weight of isobutene; other, 4.4 wt%. The metered mixed butene (the molar ratio of maleic anhydride to the effective component (terminal olefin) in the mixed olefin is 1:1) is introduced into 1L of isoamyl acetate solution containing 1mol/L maleic anhydride, 0.05mol/L azodiisobutyl cyanide and 0.2mol/L divinylbenzene under the nitrogen atmosphere, the nitrogen is stamped to the relative pressure of 0.5MPa, and the system is reacted for 6 hours at 70 ℃. And (3) centrifugally separating the reacted system for 30 minutes under the condition of 5000rad/min by a centrifugal machine to obtain cross-linked mixed butene/maleic anhydride polymer microspheres A4, washing and purifying by normal hexane, and drying in vacuum. Wherein the amount of mixed butene (active component) was 100mol, the amount of divinylbenzene was 20mol, and the amount of initiator was 5mol, relative to 100mol of maleic anhydride.
The crosslinking degree of the crosslinked mixed carbon tetra-maleic anhydride copolymer microsphere A4 is 76%, the molar ratio of the structural unit A to the structural unit B to the crosslinked structural unit is 100:100:25, and the average particle size of the copolymer microsphere is 1100nm.
Preparation example 5
Preparation of porogen A5
Ionomer microspheres were prepared as in preparation example 1 except that the amount of divinylbenzene was 155g, resulting in crosslinked α -methylstyrene/maleic anhydride polymer microspheres A5. Wherein, the amount of alpha-methyl styrene was 97.9mol, the amount of divinylbenzene was 29.2mol, and the amount of initiator was 1.2mol, relative to 100mol of maleic anhydride.
The crosslinking degree of the crosslinked maleic anhydride-alpha-methylstyrene copolymer microsphere A5 is 89%, the molar ratio of the structural unit A to the structural unit B to the crosslinked structural unit is 100:102:31, and the average particle size of the copolymer microsphere is 400nm.
Example 1
Preparation of polyethylene composition
90 parts of a linear low density polyethylene (MFR 3.5g/10min, density 0.917 g/cm) 3 Molecular weight distribution of 4) and 10 parts of a low density polyethylene (MFR 7.5g/10min, density 0.919g/cm 3 The molecular weight distribution is 7.2), 70 parts of pore-forming agent A1 and 1 part of antioxidant compound auxiliary agent are mixed in a high-speed stirrer, wherein the antioxidant is tetra (beta- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionic acid) penta The weight ratio of the tetraol ester, (2, 4-di-tert-butylphenyl) phosphite triester to the calcium stearate is 2:2:1.
After being evenly mixed, the mixture is added into a double-screw extruder for melt blending, extrusion granulation, the rotating speed of a screw is 200r/min, and the temperatures of a feeding section, a melting section, a homogenizing section and a die head are respectively as follows: 170 ℃, 180 ℃, 200 ℃ and 190 ℃ to obtain the polyethylene composition of the invention. The resulting polyethylene composition was dried. The properties of the polyethylene composition are shown in Table 1. The polyethylene composition was melted at 200℃and tabletted, the plaques were 160-200 μm thick. Fig. 1 is an SEM photograph of a cross section of a sample of a polyethylene composition, from which it can be seen that the porogen has a uniform particle size and is uniformly distributed in the polyethylene matrix.
Example 2
Preparation of polyethylene composition
90 parts of a linear low density polyethylene (MFR 3.5g/10min, density 0.917 g/cm) 3 Molecular weight distribution of 4) and 10 parts of a low density polyethylene (MFR 7.5g/10min, density 0.919g/cm 3 The molecular weight distribution is 7.2), 30 parts of pore-forming agent A2 and 1 part of antioxidant compound auxiliary agent are blended in a high-speed stirrer, wherein the weight ratio of tetra (beta- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionic acid) pentaerythritol ester, (2, 4-di-tert-butylphenyl) phosphite triester and calcium stearate is 2:2:1.
After being evenly mixed, the mixture is added into a double-screw extruder for melt blending, extrusion granulation, the rotating speed of a screw is 200r/min, and the temperatures of a feeding section, a melting section, a homogenizing section and a die head are respectively as follows: 170 ℃, 180 ℃, 200 ℃ and 190 ℃ to obtain the polyethylene composition of the invention. The resulting polyethylene composition was dried. The properties of the polyethylene composition are shown in Table 1. The polyethylene composition was melted at 200℃and tabletted, the plaques were 160-200 μm thick. Fig. 2 is an SEM photograph of a cross section of a sample of the polyethylene composition, from which it can be seen that the porogen has a uniform particle size and is uniformly distributed in the polyethylene matrix.
Example 3
Preparation of polyethylene composition
75 parts of a linear low density polyethylene (MFR 3.5g/10min, density 0.917 g/cm) 3 Molecular weight ofDistribution 4), 25 parts of a low density polyethylene (MFR 7.5g/10min, density 0.919g/cm 3 The molecular weight distribution is 7.2), 50 parts of pore-forming agent A3 and 1 part of antioxidant compound auxiliary agent are mixed in a high-speed mixer, wherein the weight ratio of tetra (beta- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionic acid) pentaerythritol ester, (2, 4-di-tert-butylphenyl) phosphite triester and calcium stearate is 2:2:1.
After being evenly mixed, the mixture is added into a double-screw extruder for melt blending, extrusion granulation, the rotating speed of a screw is 200r/min, and the temperatures of a feeding section, a melting section, a homogenizing section and a die head are respectively as follows: 170 ℃, 180 ℃, 200 ℃ and 190 ℃ to obtain the polyethylene composition of the invention. The resulting polyethylene composition was dried. The properties of the polyethylene composition are shown in Table 1. The polyethylene composition was melted at 200℃and tabletted, the plaques were 160-200 μm thick. Fig. 3 is an SEM photograph of a cross section of a sample of the polyethylene composition, from which it can be seen that the porogen particles are uniform in size and uniformly distributed in the polyethylene matrix.
Example 4
Preparation of polyethylene composition
90 parts of a linear low density polyethylene (MFR 3.5g/10min, density 0.917 g/cm) 3 Molecular weight distribution of 4) and 10 parts of a low density polyethylene (MFR 7.5g/10min, density 0.919g/cm 3 The molecular weight distribution is 7.2), 90 parts of pore-forming agent A4 and 1 part of antioxidant compound auxiliary agent are blended in a high-speed stirrer, wherein the weight ratio of tetra (beta- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionic acid) pentaerythritol ester, (2, 4-di-tert-butylphenyl) phosphite triester and calcium stearate is 2:2:1.
After being evenly mixed, the mixture is added into a double-screw extruder for melt blending, extrusion granulation, the rotating speed of a screw is 200r/min, and the temperatures of a feeding section, a melting section, a homogenizing section and a die head are respectively as follows: 170 ℃, 180 ℃, 200 ℃ and 190 ℃ to obtain the polyethylene composition of the invention. The resulting polyethylene composition was dried. The properties of the polyethylene composition are shown in Table 1.
Example 5
Preparation of polyethylene composition
90 parts of linear low density polyethyleneAlkene (MFR 3.5g/10min, density 0.917 g/cm) 3 Molecular weight distribution of 4), 10 parts of a low density polyethylene (MFR of 7.5g/10min, density of 0.919g/cm 3 The molecular weight distribution is 7.2), 100 parts of pore-forming agent A1 and 1 part of antioxidant compound auxiliary agent are mixed in a high-speed mixer, wherein the weight ratio of tetra (beta- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionic acid) pentaerythritol ester, (2, 4-di-tert-butylphenyl) phosphite triester and calcium stearate is 2:2:1.
After being evenly mixed, the mixture is added into a double-screw extruder for melt blending, extrusion granulation, the rotating speed of a screw is 200r/min, and the temperatures of a feeding section, a melting section, a homogenizing section and a die head are respectively as follows: 170 ℃, 180 ℃, 200 ℃ and 190 ℃ to obtain the polyethylene composition of the invention. The resulting polyethylene composition was dried. The properties of the polyethylene composition are shown in Table 1. The polyethylene composition was melted at 200℃and tabletted, the plaques were 160-200 μm thick. Fig. 4 is an SEM photograph of a cross section of a sample of the polyethylene composition, from which it can be seen that the porogen particles are uniform in size and uniformly distributed in the polyethylene matrix.
Comparative example 1
A polyethylene composition was prepared as in example 1, except that the porogen A1 was 15 parts. The properties of the polyethylene composition are shown in Table 1. Fig. 5 is an SEM photograph of a cross section of a sample of the polyethylene composition, and it can be seen from fig. 5 that the porogen has a uniform particle size, but a small number and a non-uniform distribution.
Comparative example 2
90 parts of a linear low density polyethylene (MFR 3.5g/10min, density 0.917 g/cm) 3 Molecular weight distribution of 4) and 10 parts of a low density polyethylene (MFR 7.5g/10min, density 0.919g/cm 3 Molecular weight distribution of 7.2), 100 parts of nano CaCO 3 Powder (10000 meshes of Shanghai river chemical industry Co., ltd.) and 1 part of antioxidant compound auxiliary agent are mixed in a high-speed mixer, wherein the weight ratio of pentaerythritol tetra (beta- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionate), phosphoric triester (2, 4-di-tert-butylphenyl) phosphite and calcium stearate is 2:2:1.
After being evenly mixed, the mixture is added into a double-screw extruder for melt blending, extrusion granulation, the rotating speed of a screw is 200r/min, and the temperatures of a feeding section, a melting section, a homogenizing section and a die head are respectively as follows: 170 ℃, 180 ℃, 200 ℃ and 190 ℃ to obtain the polyethylene composition of the invention. The resulting polyethylene composition was dried. The properties of the polyethylene composition are shown in Table 1. The polyethylene composition was melted at 200℃and tabletted, the plaques were 160-200 μm thick. Fig. 6 is an SEM photograph of a cross-section of a sample of the polyethylene composition, showing significant agglomeration of porogens.
Comparative example 3
90 parts of a linear low density polyethylene (MFR 3.5g/10min, density 0.917 g/cm) 3 Molecular weight distribution of 4) and 10 parts of a low density polyethylene (MFR 7.5g/10min, density 0.919g/cm 3 Molecular weight distribution of 7.2), 100 parts of nano BaSO 4 Powder (Sa Ha Liben Blanc FixeMicro, organic coating, d50=0.7 mu m) and 1 part of antioxidant compound auxiliary agent are blended in a high-speed stirrer, wherein the weight ratio of tetra (beta- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionic acid) pentaerythritol ester, (2, 4-di-tert-butylphenyl) phosphite triester to calcium stearate is 2:2:1.
After being evenly mixed, the mixture is added into a double-screw extruder for melt blending, extrusion granulation, the rotating speed of a screw is 200r/min, and the temperatures of a feeding section, a melting section, a homogenizing section and a die head are respectively as follows: 170 ℃, 180 ℃, 200 ℃ and 190 ℃ to obtain the polyethylene composition of the invention. The resulting polyethylene composition was dried. The properties of the polyethylene composition are shown in Table 1. The polyethylene composition was melted and film-pressed at 200℃and the film thickness was 160-200. Mu.m. Fig. 7 is an SEM photograph of a cross-section of a sample of the polyethylene composition, and it can be seen that significant agglomeration of porogens occurs.
Comparative example 4
A polyethylene composition was prepared as in example 1, except that the porogen A1 was 135 parts. The properties of the polyethylene composition are shown in Table 1.
Comparative example 5
A polyethylene composition was prepared as in example 1, except that the porogen used was porogen A5. The properties of the polyethylene composition are shown in Table 1.
TABLE 1
Figure BDA0003329487810000201
As can be seen from Table 1, the polyethylene composition provided by the invention has a Melt Flow Rate (MFR) meeting the casting process requirements, and ΔH mPE And DeltaH m composition When the difference meets the range of the invention, the crosslinked maleic anhydride copolymer microspheres can be ensured to be uniformly distributed in the composition, so that the composition has better mechanical property and can meet the requirement of the stretching multiplying power of the breathable film.
According to the invention, the organic pore-forming agent and the polyolefin matrix resin with uniform particles are reasonably selected, so that the uniformity of the dispersion of the pore-forming agent in the matrix resin is obviously improved under the condition of not additionally using a coupling agent and a dispersing agent, and the mechanical property of the polyolefin resin for the breathable film is improved to a certain extent.
Test case
The polyethylene compositions of examples and comparative examples were fed into an extrusion casting machine to melt and cast a cast sheet, the extrusion temperature was 210 to 240℃and the chill roll temperature was 20 to 60℃to prepare polyethylene cast films. The cast film was uniaxially stretched 3 times to obtain a polyethylene microporous breathable film having an average thickness of 30 μm, and the heat setting temperature was 85 ℃. The properties of the polyethylene microporous breathable film are shown in table 2.
TABLE 2
Project Water vapor transmission rate (g/m) 2 ·24h)
Example 1 3170
Example 2 3110
Example 3 3150
Example 4 3090
Example 5 3060
Comparative example 1 1860
Comparative example 2 2540
Comparative example 3 2660
Comparative example 4 2710
Comparative example 5 2720
As can be seen from table 2, the polyethylene breathable film prepared from the polyethylene composition provided by the present invention has high breathability. The properties of the polyethylene composition and the prepared breathable film are inferior to those of the examples under the condition of no addition of dispersing agent or coupling agent by using inorganic pore-forming agent. The polyethylene breathable film prepared by the embodiment of the invention has high breathability and can be widely applied to the fields of disposable medical and health products, water-blocking and moisture-permeable materials and the like.
The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited thereto. Within the scope of the technical idea of the invention, a number of simple variants of the technical solution of the invention are possible, including combinations of the individual technical features in any other suitable way, which simple variants and combinations should likewise be regarded as being disclosed by the invention, all falling within the scope of protection of the invention.

Claims (20)

1. A polyethylene composition, which is characterized by comprising 100 parts by weight of polyethylene, 20-110 parts by weight of pore-forming agent and 0.1-2.5 parts by weight of antioxidant compound auxiliary agent;
The pore-forming agent is cross-linked maleic anhydride copolymer microsphere, the cross-linking degree of the copolymer microsphere is more than or equal to 65%, and the average particle size is 500-2000nm.
2. The polyethylene composition according to claim 1, wherein the composition comprises 100 parts by weight of polyethylene, 30-90 parts by weight of porogen and 0.2-1.5 parts by weight of antioxidant compounding aid;
preferably, the crosslinking degree of the copolymer microsphere is more than or equal to 70%, and the average particle size is 800-1700nm.
3. The polyethylene composition according to claim 1 or 2, wherein the polyethylene has a melting enthalpy Δh mPE The polyethylene composition has a melting enthalpy of DeltaH m composition ；
Wherein DeltaH mPE And DeltaH m composition The difference is 8-48J/g, preferably 10-45J/g.
4. A polyethylene composition according to any of claims 1-3, wherein the crosslinked maleic anhydride copolymer microsphere copolymer comprises structural units a from maleic anhydride and structural units B from comonomer M and crosslinked structural units;
in the copolymer, the molar ratio between the structural unit a, the structural unit B and the crosslinking structural unit is 100:100-120:1-40, preferably 100:100-105:10-30 parts of a base;
preferably, the comonomer M is selected from at least one of a compound represented by formula (I), vinyl acetate, mixed carbon four and mixed carbon five;
Figure FDA0003329487800000011
Wherein, in the formula I, R is H or methyl.
5. The polyethylene composition according to any one of claims 1 to 4, wherein the method of preparing the crosslinked maleic anhydride copolymer microspheres comprises the steps of:
in an organic solvent, in the presence of an initiator, carrying out contact reaction on maleic anhydride, a comonomer M shown in a formula (I) and a crosslinking agent; obtaining the crosslinked maleic anhydride copolymer microspheres;
the comonomer M is at least one selected from a compound shown in a formula (I), vinyl acetate, mixed carbon four and mixed carbon five;
Figure FDA0003329487800000021
wherein, in the formula I, R is H or methyl.
6. The polyethylene composition according to claim 5, wherein the comonomer M is used in an amount of 50 to 150mol, preferably 75 to 100mol, relative to 100mol of maleic anhydride; the crosslinking agent is used in an amount of 1 to 40mol, preferably 10 to 20mol; the initiator is used in an amount of 0.05 to 10mol, preferably 1 to 1.5mol.
7. The polyethylene composition according to claim 5 or 6, wherein the organic solvent comprises an alkyl ester of an organic acid;
preferably, the initiator is selected from at least one of dibenzoyl peroxide, dicumyl peroxide, di-t-butyl peroxide, lauroyl peroxide, t-butyl peroxybenzoate, diisopropyl peroxydicarbonate, dicyclohexyl peroxydicarbonate, azobisisobutyronitrile and azobisisoheptonitrile;
Preferably, the cross-linking agent is selected from divinylbenzene and/or acrylate cross-linking agents containing at least two acrylate groups;
more preferably, the structural formula of the acrylate group is: -O-C (O) -C (R') =ch 2 R' is H or C 1 -C 4 Is a hydrocarbon group.
8. The polyethylene composition according to any one of claims 5-7, wherein the cross-linking agent is selected from at least one of divinylbenzene, propylene glycol diacrylate, propylene glycol dimethacrylate, ethylene glycol diacrylate, ethylene glycol dimethacrylate, trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, diethylene glycol diacrylate, pentaerythritol tetraacrylate, pentaerythritol pentaacrylate, pentaerythritol hexaacrylate, and ethoxylated polyfunctional acrylate;
preferably, the crosslinking agent is divinylbenzene.
9. The polyethylene composition according to any one of claims 5-8, wherein the reaction conditions comprise: the reaction is carried out in the presence of inert atmosphere, the reaction temperature is 50-90 ℃, the reaction time is 3-15h, and the reaction pressure is 0.1-1MPa.
10. The polyethylene composition according to any one of claims 1-9, wherein the polyethylene is a linear low density polyethylene and a low density polyethylene;
preferably, the linear low density polyethylene is used in an amount of 60 to 99 parts by weight, preferably 70 to 95 parts by weight, based on 100 parts by weight of polyethylene; the low density polyethylene is used in an amount of 1 to 40 parts by weight, preferably 5 to 30 parts by weight.
11. The polyethylene composition according to claim 10, wherein the linear low density polyethylene is a copolymer of ethylene and an α -olefin; preferably, the alpha-olefin is selected from at least one of butene, hexene and octene;
preferably, the linear low density polyethylene has a density of 0.905g/cm 3 -0.935g/cm 3 ；
Preferably, the linear low density polyethylene has a melt flow rate of 0.5g/10min to 10g/10min, preferably 2g/10min to 6g/10min, at 190℃and under a load of 2.16 kg;
preferably, the linear low density polyethylene has a molecular weight distribution of from 2 to 12, preferably from 2 to 10.
12. The polyethylene composition according to claim 10 or 11, wherein the low density polyethylene has a density of 0.913g/cm 3 -0.934g/cm 3 ；
Preferably, the low density polyethylene has a melt flow rate of 0.1g/10min to 12g/10min, preferably 2g/10min to 9g/10min, at 190℃and under a load of 2.16 kg;
Preferably, the low density polyethylene has a molecular weight distribution of 5 to 11, preferably 6 to 10.
13. The polyethylene composition according to any one of claims 10-12, wherein the polyethylene composition further comprises at least one member selected from the group consisting of: medium density polyethylene, high density polyethylene, ultra low density polyethylene, ultra high molecular weight polyethylene, polypropylene, propylene-based copolymers, ethylene-vinyl acetate copolymers, ethylene methyl acrylate copolymers, polyolefin plastomers, polyolefin elastomers and polybutenes.
14. The polyethylene composition of any of claims 1-13, wherein the antioxidant co-agent comprises an antioxidant and an acid absorber;
preferably, the weight ratio of the antioxidant to the acid absorber is 1-6:1, a step of;
preferably, the antioxidant is selected from at least one of pentaerythritol tetrakis [ beta- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionate ], phenyl tri (2, 4-di-tert-butyl) phosphite, stearyl propionate and alkylated polyphenols;
preferably, the acid absorber is a stearate, preferably at least one selected from the group consisting of calcium stearate, zinc stearate and sodium stearate.
15. The polyethylene composition according to claim 14, wherein the antioxidant co-agent is a mixture of pentaerythritol tetrakis (β - (3, 5-di-tert-butyl-4-hydroxyphenyl) propionate), trisaccharide (2, 4-di-tert-butylphenyl) phosphite and calcium stearate, wherein the weight ratio of pentaerythritol tetrakis (β - (3, 5-di-tert-butyl-4-hydroxyphenyl) propionate), trisaccharide (2, 4-di-tert-butylphenyl) phosphite to calcium stearate is (1-3): (1-3): 1.
16. The polyethylene composition according to any one of claims 1-15, wherein the polyethylene composition is free of coupling agents and dispersants.
17. Use of the polyethylene composition according to any one of claims 1 to 16 in a polyolefin microporous breathable film.
18. A process for preparing a polyethylene composition according to any one of claims 1 to 16, comprising:
(1) Mixing polyethylene, a pore-forming agent and an antioxidant composite auxiliary agent to obtain a mixture;
(2) And carrying out melt blending extrusion, granulating and drying on the mixture in a double-screw extruder to obtain the polyethylene composition.
19. The production method according to claim 18, wherein the twin-screw extruder has a rotation speed of 150 to 400r/min;
preferably, the temperatures of the feeding section, melting section, homogenizing section and die of the twin-screw extruder are 150-180deg.C, 165-200deg.C, 180-215 deg.C, 175-210 deg.C, respectively.
20. A polyolefin microporous breathable film, characterized in that said microporous breathable film is made from the polyethylene composition of any of claims 1-16.
CN202111273490.9A 2021-10-29 2021-10-29 Polyethylene composition, preparation method and application thereof, and polyolefin microporous breathable film Pending CN116063770A (en)

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CN101695869A (en) * 2009-10-30 2010-04-21 沧州明珠塑料股份有限公司 Preparation method of polyolefin microporous film
CN104558751A (en) * 2013-10-25 2015-04-29 中国石油化工股份有限公司 Composition and method for preparing ultrathin gas-permeable film
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