CN1025678C - Preparation of styrene polymer foam and product - Google Patents
Preparation of styrene polymer foam and product Download PDFInfo
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- CN1025678C CN1025678C CN 88108435 CN88108435A CN1025678C CN 1025678 C CN1025678 C CN 1025678C CN 88108435 CN88108435 CN 88108435 CN 88108435 A CN88108435 A CN 88108435A CN 1025678 C CN1025678 C CN 1025678C
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Abstract
The present invention relates to a method for producing an extrusion foam body of a styrene polymer, which comprises the following steps: plastifying the synthetic resin of an alkenyl aromatic group; adding the plastified resin to a mixing device; adding a foaming agent to the mixing device; sustaining pressure in the mixing device to be equal to or larger than the equilibrium vapor pressure of the foaming agent in a mixture of the synthetic resin of an alkenyl aromatic group and the foaming agent; making the mixture pass through a cooling device and pass through a mould of which the pressure is larger than atmospheric pressure; maintaining a minimum critical pressure drop deltaPc of specific determination between the inlets of the mixing device and the mould.
Description
The present invention relates to the preparation of styrene polymer foam body and the product that makes, particularly relate at the scale operation microvesicle and contain in the various novel sealing microvesicle foams processes of new gaseous mixture the method for control top layer character.
One of main application of styrene polymer foam body is to be used in the thermal isolation aspect.Be used for the requirement of heat-insulating styrene polymer foam body and have less microvesicle and fabulous dimensional stability, it is desirable to keep as far as possible for a long time the thermal insulation values of foams.The present invention considers extruding styrene polymer foam body emphatically, compares with so-called molded particle foams, and this crushed foam body has microvesicle sphere diameter quite uniformly.The crushed foam body also can be applicable to usually said decoration field, former cystose is cut into decorate foam, be used as finishing material or as the substrate of further finishing material.
At present the known technology of preparation sponge polystyrene comprises the thermoplastic resin adhesive of fusion volatility vaporized chemical or whipping agent is expressed to the lower zone of pressure, the volatility vaporized chemical evaporates there, and in extruding glue, form many gas micropores, crushed foam glue cooling subsequently forms from foams frame or cellular.People have known many kinds of whipping agents (also being called foaming agent or vaporized chemical), these whipping agents mainly belong to fat hydrocarbon, for example butane, hexane, heptane, pentane or the like, under pressure, be dissolved in gas in the polymkeric substance, as carbonic acid gas, some fluorinated hydrocarbon such as trichlorofluoromethane, trifluoromethane etc. also can use such as hydrochloric ethers such as methyl chlorides.It is found that many these class whipping agents are gratifying to various alkenyl aromatic polymer material.Yet under processing conditions, uncontrolled volatility can cause some defective, particularly in top layer poor performance, the reticulated foams body pore arranged, venting and poor dimensional stability in mould.These defectives make to be interrupted to produce and form substandard products, and production cost is increased.
In the past, undercompounding that it is generally acknowledged molten polymer and whipping agent is the reason that produces pore.In typical production technique, controller is designed to monitor foam surface, and when undercompounding occurring, increases the speed of mixing tank.If it is still improper that mixer speed increases the rear surface, can carry out other so and regulate, comprise that the flow, mould interval and the foam that reduce whipping agent and polymkeric substance break away from speed.Yet these changes have reduced the output of particular device.In the past, warning signal never when beginning to become improper, mixing condition takes place, the homogeneity control of product performance is a technology rather than science to a great extent, because change a kind of variable factor in the course of processing, the multiple product performance is changed.The flow velocity that for example temporarily reduces whipping agent helps to compensate the excessive whipping agent that gathers in the whole extrusion system, but this correction also can produce the foamed products with higher density.In fact, produce because condition variation at random can cause pore, it is necessary every two hours the extruding condition of styrene polymer foam body being made some change.
In for a long time, people use the mixture of methyl chloride or methyl chloride and chlorofluorocarbon to do whipping agent, extruding styrene polymer foam body separately.
When in extruding, adopting such system, usually must aging for some time, methyl chloride is left away from microvesicle and air is entered wherein by the microvesicle wall by suitable diffusion process.All or part of use methyl chloride is made whipping agent in foams, and digestion time is long concerning thicker stripper plate, can bring the trouble in the storage.Store or during excision forming at such foams, need arouse attention, will keep the well-ventilated the bad physical properties of methyl chloride.
From the technology viewpoint, have been found that some halogen-containing compound is being useful as Refrigerant 12 aspect the preparation extruding styrene polymer foam body.Therefore, people wish part or this compounds of cancel all in the application of finally discharging into the atmosphere at present, it is believed that these compounds discharge into the atmosphere, can reduce usefulness, as the ozonosphere of sun shielding layer.
Foam by extrusion and preparation thereof quite at length have been discussed in following United States Patent (USP), and these U.S. Patent numbers are 2,409,910; 2,515,250; 2,669,751; 2,848,428; 2,928,130; 3,121,130; 3,121,911; 3,770,688; 3,815,674; 3,960,792; 3,966,381; 4,085,073; 4,146,563; 4,229,396; 4,312,910; 4,421,866; 4,438,224; 4,454,086 and 4,486,550.
Use the United States Patent (USP) 3,960 of M.Nakamura, the method described in 792 makes the stable styrene polymer foam body of special ideal.
Preparation styrene polymer foam body can use the mixture of chloric ethane, methyl chloride and Refrigerant 12 or chloric ethane and Refrigerant 12 to make whipping agent, and United States Patent (USP) 4,393 has been described the preparation of these foams in 016 and 4,451,417 respectively.United States Patent (USP) 4,344 has been narrated in 710 and 4,424,287 and has been used the another kind of foaming agent system that is made of carbonic acid gas and paraffinic hydrocarbons.
The also available United States Patent (USP) 4,636 of alkenyl aromatic polymer foams, the method preparation described in 527, use carbonic acid gas, the mixture of chloric ethane and hydrocarbon compoud containing fluorine is made whipping agent, and hydrocarbon compoud containing fluorine can be selected from Refrigerant 12 arbitrarily, 1-chloro-1, the mixture of 1-C2H4F2 C2H4F2 and these hydrocarbon compoud containing fluorine.
People wish to obtain a kind of effective means, be used for preparing do not produce pore, the top layer performance is good and the alkenyl aromatic polymer foams of not exitting in mould.
People also wish with method of the present invention, use the alkenyl aromatic polymer foams that the more satisfied whipping agent of surrounding environment is prepared a kind of novelty.
Be easy to reach according to the present invention, these effects and other advantage.For the mean diameter of producing airtight microvesicle is that 0.05 millimeter (mm) arrives about 3.5 millimeters, density is about 16-80 kilogram/rice
3, 52 centimetres of 1.3 centimetres of minimum cross-section thickness and smallest cross-section areas
2Alkenyl aromatic synthetic resins crushed foam body, method therefor comprises the following steps: (a) thermoplastification alkenyl aromatic synthetic resins: (b) plasticized resin and whipping agent are incorporated into inlet pressure and remain on P
MMixing device in, this pressure is greater than the equilibrium vapour pressure of the whipping agent in the mixture of alkenyl aromatic synthetic resins and whipping agent; (c) make mixture pass through refrigerating unit; (d) making the refrigerative mixture is P by die entrance pressure
DMould, this pressure is greater than normal atmosphere; In all these steps, the quality that △ P comes the control foam surface is fallen by the pressure of accurately keeping from the mixer entrance to the die entrance, to the given resin and the mixture of whipping agent, this pressure falls more than or equal to the emergent pressure of the minimum of rule of thumb predicting and falls △ Pc.
According to the inventive method, within the scope of the present invention, consider to prepare alkenyl aromatic synthetic resins crushed foam with known whipping agent.
According to the inventive method, within the scope of the present invention, further consider to use the more gratifying whipping agent of surrounding environment is prepared alkenyl aromatic synthetic resins foams that these foams record with the described testing method in back has fabulous surface property.
According to the inventive method, within the scope of the present invention, further consider preparation polystyrene crushed foam body.
The method according to this invention is further considered preparation styrene/acrylic acid co-polymer crushed foam body within the scope of the invention.
The method according to this invention, further consider the styrene/acrylic acid co-polymer crushed foam body of preparation ionomer within the scope of the invention.
In the many decades before the present invention, it is believed that under given blowing temperature,, just may produce the airtight microvesicle low density foam of good quality with good top layer characteristic as long as the maintenance die pressure is higher than the vapour pressure of whipping agent system.Sometimes the pore and epidermis slight crack or the texture that contain different numbers with the regular foam body of current methods preparation, and, with containing acceptable whipping agent of surrounding environment such as methane, ethane, carbonic acid gas, nitrogen, water and hydrogenous some hydrocarbon compoud containing fluorine and chlorofluorocarbon whipping agent system, being difficult to production low density crushed foam body.
Obviously different, prepared in accordance with the present invention foams with prior art are for as one man having the low density crushed foam body that top layer performance and physicals change, the present invention has also reduced the waste material ratio, make starting material obtain better utilised, reduced cost, the volatile organic compounds that is dispersed into simultaneously in the atmosphere is less.
Fig. 1～19th according to the schematic diagram of each technology of the present invention, comprises the mensuration of falling to die entrance pressure from mixer entrance.
Opposite with prior art, seriously degenerate so that in fact before final froth product surface forms pore at extruding condition, the present invention sends " pre-warning " signal, particularly is easy to the △ P in the Instrument measuring continuous production, if just the value of △ P is lower than the set-point signal that gives the alarm.
It is found that it is effective that following step diminishes to correction △ P value drift.At first, the temperature of mixing device is reduced the several years; The second, part is closed the throttling valve between mixing tank and the mould; The 3rd, reduce the flow velocity of whipping agent, thereby increase the viscosity of partially mixed polymkeric substance and whipping agent; The 4th, increase velocity of polymer (promptly increasing the RPM of the toothed gear pump that is installed in the mixing tank front), thereby increase the viscosity of partially mixed polymkeric substance and whipping agent.
" alkenyl aromatic synthetic resins " is meant the solid resin (or polymkeric substance) of the polymerisable alkenyl aromatic compounds of one or more following general formulas that contain at least 60% weight.
Ar represents aryl or benzene series halogenated aromatic alkyl in the formula, and R is hydrogen or methyl.
The example of such alkenyl aromatic resin is a vinylbenzene, alpha-methyl styrene, neighbour-vinyl toluene, between-vinyl toluene, p-methylstyrene, the ar-ethyl styrene, ar-vinyl-dimethyl benzene, the solid homopolymer of ar-chlorostyrene or ar-bromostyrene, the solid copolymer of one or more such alkenyl aromatic compounds and a small amount of other easy polymeric olefinic compounds such as methyl methacrylate, vinyl cyanide, maleic anhydride, citraconic anhydride, itaconic anhydride, vinylformic acid, methacrylic acid and rubber enhanced styrene polymer etc.
Alkenyl aromatic synthetic resins also comprises and blended solid homopolymer and solid copolymers such as other solid homopolymer and solid copolymer and a small amount of other polymeric thermoplastic compound such as polyethylene, polycarbonate, polymethylmethacrylate, polyphenylene oxides.
Useful especially is cinnamic solid homopolymer, polystyrene, vinylbenzene and acrylic acid multipolymer (SAA) and SAA ionomer, and wherein ionomer is the cross-linked polymer of sodium, calcium, lithium, potassium and magnesium.
When producing the SAA ionomer, the neutralizing agent that is suitable for that joins among the SAA of the thermoplastification in the extrusion machine has sodium hydroxide, lithium hydroxide, potassium hydroxide, magnesium oxide, calcium hydroxide and calcium stearate, but is not limited to these.The add-on of neutralizing agent is the about percent 0.1 parts of neutralizing agents to 1 part of weight of per 100 parts of weight resins, and preferably percent 0.1 to 0.6 part.
The whipping agent of Shi Yonging is if commercially pure, then normally gratifying in the embodiment of this invention.
Some whipping agent or blowing agent blends contain at least a hydrocarbon compoud containing fluorine, and the rate of permeation of this hydrocarbon compoud containing fluorine by the alkenyl aromatic resin polymkeric substance is not more than 0.017 times of the rate of permeation of nitrogen by this object, thermal conductivity and is not more than 1.11612 * 10
-2Kilocalorie/meter hour ℃, further the low permeability whipping agent of restriction is the compound of following formula.
R in the formula
1Be selected from chlorine, fluorine, methyl, ethyl, chloro methyl, dichloro-methyl, two fluoro methyl, chlorine methyl fluoride, fluoro methyl and trifluoromethyl respectively, R
2Be selected from chlorine, fluorine, methyl, trifluoromethyl and hydrogen respectively, further limit no more than three carbon atoms of this compound, if this compound only contains 2 fluorine atoms as halogen atom, this compound mixture that must contain 3 carbon atoms or these compounds must satisfy above-mentioned restriction so.
The low permeability whipping agent that satisfies above-mentioned requirements is: 1,1, and 1-trifluoro propane, 2,2-difluoropropane, 1,1,2,2-Tetrafluoroethane, 1,1,1,2-Tetrafluoroethane, 1,1,1,2-tetrafluoro-2-monochloroethane, 1,1,1-three fluoro-2-monochloroethane, 1,1-two chloro-2,2,2-Halothane, pentafluoride ethane, 1,1,2-Halothane, 1,1,1-Halothane, octafluoropropane and 1,1-two fluoro-1-monochloroethane, Refrigerant 12 and trichlorofluoromethane and their mixture.All above-mentioned these compounds have the rate of permeation and the thermal conductivity of requirement.
Particularly suitable be 1,1,1,2-Tetrafluoroethane (CFC-134A), 1,1,1,2-tetrafluoro-2-monochloroethane (CFC-124A), 1,1,1-Halothane (CFC-143A), 1,1-two fluoro-1-monochloroethane (CFC-142B) and Refrigerant 12 (CFC-12).
Yet, because environment requires to reduce or restriction use CFC-12.
According to the present invention, consider the problem and the restriction of loss ozone during foams or reduce the concentration of complete halogenated chlorofluorocarbon in preparation, can adopt the more satisfied other whipping agent of surrounding environment is comprised: chloric ethane (EtCl), carbonic acid gas (CO
2), chloro methylene fluoride, 1,1-C2H4F2 C2H4F2, nitrogen (N
2), water (H
2O), aliphatic hydrocarbon comprises the mixture of methane, ethane, ethene, propane, propylene, butane, butylene, Trimethylmethane, pentane, neopentane, iso-pentane, hexane, heptane and any of these whipping agent.
Particularly suitable be methane, ethane, propane, chloric ethane, carbonic acid gas, nitrogen, water and chloro methylene fluoride (CFC-22).
The term that uses in this specification sheets " whipping agent " is meant these two kinds in the mixture of single whipping agent and whipping agent.
In the method for the present invention, the consumption of whipping agent is the whipping agents of per 100 parts of weight alkenyl aromatic synthetic resins about 3 to about 30 parts of weight.
The inventive method prepares that used concrete whipping agent is (with the whipping agent gross weight is benchmark, and all percentage ratios are weight percentage) in the alkenyl aromatic synthetic resins foams process:
(1) CFC-12, CFC-124, CFC-134A, CFC-142B, CFC-143A and their mixture;
(2) any CFC uses separately or to contain 6%CO
2Mixture use.
These whipping agents that exemplify above are not have fully to leave over, and only are some representational examples, for example may contain the whipping agent of methane, nitrogen and/or other known whipping agent such as methyl chloride in addition.
The method according to this invention when the preparation foams, usually needs to add the size that nucleator is controlled microvesicle.Talcum powder, Calucium Silicate powder, indigo or the like is the suitable agent of control microvesicle size.Also wish to add resistance alkene agent such as a hexabromocyclododecane or a chlorine pentabromo-hexanaphthene, extrusion aid such as barium stearate or calcium stearate and acid purification agent such as magnesium oxide or tetrasodium pyrophosphate.
The average microvesicle diameter of prepared according to the methods of the invention alkenyl aromatic resin polymer foam is 0.05-3.5mm, 0.08-3.0mm preferably, and density is 16-80 kilogram/rice
3, 16-64 kilogram/rice preferably
3
The minimum cross-section thickness of prepared according to the methods of the invention alkenyl aromatic resin foam of polymers is 1.3 centimetres, and smallest cross-section area is 52 centimetres
2
According to the present invention, usually with United States Patent (USP) 2, it is the easiest preparing the alkenyl aromatic resin polymkeric substance with the method for narrating shown in 669,751, in this patent volatile fluid and/or gas foaming agent is injected in the polymer melt of the thermoplastification in the extrusion machine.Thermoplastification glue is from extrusion machine feeds mixing tank, and this mixing tank is rotary mixing tank, the rotor seal that a strap bolt is wherein arranged in mixing tank, the internal surface of useful threaded stud of this mixing apparatus and the mutual interlock of rotor.Thermoplastification glue imports the mixer entrance end from extrusion machine, and discharges from exit end, usually with axial flow.Second possible decanting point that volatile fluid and/or gas foaming agent join in the thermoplastified polymer molten mass is mixing tank rather than extrusion machine.Gel comes out from mixing tank, and by as United States Patent (USP) 2,669, the water cooler described in 751 enters the mould of extruding ordinary rectangular plate from water cooler.Like the general category extrusion system and preferably extrusion system see United States Patent (USP) 3,966,381.
Second method is that two extrusion machine series connection are placed, and whipping agent joins in first extrusion machine, and mixing device such as interface surface producer (ISG) are placed between two extrusion machines, or second extrusion machine is used as mixing device.First extrusion machine thermoplastified polymer, if but whipping agent is added in first extrusion machine, also can become mixing device.Second extrusion machine is water cooler, if but whipping agent is added in second extrusion machine, also can become mixing device.The thermoplastified polymer molten mass can further mix and/or cool off before leaving mould after leaving second extrusion machine.
Term in this specification sheets " mixing device " refers to the place that adds whipping agent, for example comprises ISG, extrusion machine or rotary mixing tank.
Term " refrigerating unit " is meant the device of cooling thermoplastified polymer molten mass, for example comprises extrusion machine, ISG and water cooler.
During foam produced according to the present invention, whipping agent can join in the resin by any usual manner.Usually blowing agent blends is filled in the thermoplastification alkenyl aromatic resin, and before being squeezed into foams, mixes.Whipping agent can and be incorporated in the thermoplastification resin as the mixed flow perfusion, perhaps uses wherein as an independent fluid streams.For the uniform product, whipping agent and the thermoplastification resin that are met requirement must thorough mixing.Can in all sorts of ways and mix, comprise rotary mixing tank such as extrusion machine, the interface surface producer that uses in so-called static mixer or the United States Patent (USP) 3,751,377 and 3,817,669.
The method according to this invention, with United States Patent (USP) 2,669, the similar approach shown in 751, the alkenyl aromatic synthetic resins extrusion machine of packing into, resin carries out thermoplastification there, produces extruding alkenyl aromatic synthetic resins foams.
The resin of thermoplastification is by pressure control device such as toothed gear pump, and the discharging pressure of this pressure control device control extrusion machine be the more important thing is the inlet pressure of controlling mixing device such as bolt type impeller.
Whipping agent is joined in the bolt type impeller, and obtain required pressure by the temperature of regulating pressure control device and mixing device.
The material that comes out from mixing device passes through refrigerating unit, and for example United States Patent (USP) 3,014, the one or more heat exchangers shown in 702.
Yet the material that comes out from refrigerating unit also expands by mould, and the foam sample in this specification sheets under atmospheric pressure expands, yet also can produce expansion under subatmospheric situation.
Keep constant die entrance pressure, and fall in the scope at certain pressure and to regulate mixer entrance and fall to the pressure of die entrance, can make crushed foam surface quality by poor improve (or vice versa) like this, for given whipping agent, " critical the minimum pressure drop " △ Pc can measure.The combination that is decided by whipping agent and alkenyl aromatic synthetic resins falls in this emergent pressure, and is easy to by simple measuring.Experimental technique is: the maintenance die pressure is constant, adjusting mixing device pressure, has good top layer up to the crushed foam surface, does not have bubble to produce, till not exitting in mould.
The emergent pressure of measuring this moment is fallen then, and promptly mixing device pressure and die pressure is poor.
For given whipping agent and alkenyl aromatic synthetic resins, when known emergent pressure, under guaranteeing, can regulate die pressure greater than atmospheric condition.Yet die pressure adds that the emergent pressure of whipping agent is fallen must be greater than the vapour pressure of this whipping agent, good in order to produce the surface, in fact do not have pore and in mould the crushed foam body of venting hardly, this die pressure also is the minimum pressure that must keep.
In brief, it is minimum blend pressure that sum falls in the emergent pressure of die pressure and measuring, and mixing device must remain under this pressure, so that produce fine extruding alkenyl aromatic synthetic resins foams.
Mixing device must be operated under critical blend pressure at least, also can operate more than critical blend pressure.
The minimum operational pressure that needs in the mixing device is not by method, technology or system's decision, the acceptable working pressure numerical value of minimum is mainly determined by whipping agent in the mixing device, rather than determine by concrete pressing method (methods shown in Fig. 1～19) and manometric accurate position etc.The present invention can be applicable to the extrusion method of any production alkenyl aromatic synthetic resins foams.
The whole bag of tricks of the principle of the invention is used in following example explanation, but should not be construed to limitation of the present invention.
Foams can be with several different polymkeric substance, various whipping agent, and use the device preparation shown in the synoptic diagram 3.More particularly, use 3.8 centimeter of extruded machines and combine use, United States Patent (USP) 3 with 370 watts of toothed gear pumps making by Zenith, the rotary-type mixing tank of disclosed bolt type in 770,668, United States Patent (USP) 3, panel cooler shown in 014,702 and the long and narrow extrusion mould that can regulate the slit.Polymkeric substance is per hour 4.5 kilograms by speed.Each example that table 1～5 expression combines to polymkeric substance and whipping agent, the processing condition that adopted, the character of some products and fall △ Pc by the emergent pressure that experience is determined.
This specification sheets (comprising accompanying drawing) uses following abbreviation:
The PS polystyrene, weight-average molecular weight is about 200,000, uses gel permeation chromatography;
The SAA styrene/acrylic acid co-polymer, weight-average molecular weight is about 165,000, uses gel permeation chromatography;
The calcium ion cross-linked resin of CISAA SAA;
The BA whipping agent
Umber among per 100 parts of the PPh
Fahrenheit degree
The revolution of PPM per minute
PSi pound/square inch
The Tmixer mixer temperature
℃ degree centigrade
Pcf pound/cubic feet
The mm millimeter
The MD machine direction
TD is horizontal
Tf mould blowing temperature
The Poor top layer is poor, pore is arranged and exit in mould
The Fair top layer is better
The Good top layer is good, pore-free
Fabulous, the pore-free in Excellent top layer
P
MMixer entrance pressure
P
DDie entrance pressure
(or P falls in △ P pressure
M-P
D)
△ Pc emergent pressure is fallen
P when PMc measures △ Pc
MValue (being also referred to as critical blend pressure)
Table 1 explanation is under given typical die pressure, respectively more than the emergent pressure in the whipping agent mixing device and the measured and ropy foams of matter of following preparation.With the blowing agent component that contains at least a low permeability (or long-acting adiabatic blowing agent component) as CFC-12, the whipping agent of CFC-142B or both mixtures, the foams of preparation are aging after 5 years under air at room temperature, and its k-factor (℃ is the foams thermal conductivity of unit with kilocalorie/meter hour) is than the k-factor of the same foam body that replaces whipping agent with air extremely when young 3.7204 * 10
-3(table is seen the literary composition back)
Table 2 is illustrated under the given typical mould pressure, and the pressure of mixing device is higher than, when being lower than desired emergent pressure in some cases, and SAA foams (containing 3% polymeric vinylformic acid in the total weight resin) embodiment of fabulous, the good and difference of preparation quality.
This table also illustrates to be measured emergent pressure to fall required experiment is simple rather than on a large scale, shown in second example in the table 2.
Table 3 is illustrated under the given typical mould pressure, the pressure of mixing device is higher than, when being lower than desired emergent pressure in some cases, the embodiment of the ionomer SAA foams (3% polymeric vinylformic acid is arranged in the total resin weight) of fabulous, the good and difference of preparation quality.
Table 4 explanation is being below or above under the emergent pressure, the styrofoam embodiment that preparation quality is good and poor.Whipping agent is the component with high permeability, does not contain the long-acting adiabatic component that definition is discussed in the above-mentioned table 1, and even more ideal to surrounding environment.
Table 5 illustrates that whipping agent is the nonpersistent effect whipping agent with the SAA of method preparation of the present invention and novel CISA foams.
From above-mentioned explanation as seen, can implement the present invention by various changes and modifications, especially with the method for front declarative description different improvement.For this reason, clearly, except the content of setting forth and defining in the claim of back, top content only is for the present invention is described, and can not be construed to constraint of the present invention and restriction.(table is seen the literary composition back)
Claims (12)
1, a kind of production has the method for the alkenyl aromatic synthetic resins crushed foam body of airtight microvesicle, and this method comprises the following steps:
(a) thermoplastification alkenyl aromatic synthetic resins;
(b) this plasticized resin and whipping agent adding inlet pressure are remained on P
MMixing device in, this pressure is greater than the equilibrium vapour pressure of the whipping agent in the mixture of alkenyl aromatic synthetic resins and whipping agent;
(c) make mixture pass through refrigerating unit;
(d) making the refrigerative mixture is P by die entrance pressure
DMould, this pressure is greater than barometric point;
It is characterized in that, fall (△ P=P to the pressure of die entrance by monitoring continuously by mixer entrance
M-P
D), and keep this pressure to fall more than or equal to the resin of rule of thumb prediction and the minimum critical pressure of the given mixture of whipping agent falling (△ P
C) quality of coming the control foam surface.
2, according to the process of claim 1 wherein that the foaming agent composotion in the step (b) is selected from a kind of composition in the following composition, wherein all percentage ratios all are to be the weight percentage of benchmark with the whipping agent gross weight:
(1) CFC-12, CFC-124, CFC-134A, CFC-142B, CFC-143A and their mixture;
(2) any CFC in (1) or this CFC and nearly 6%CO
2Mixture;
3, according to the process of claim 1 wherein that it is the 0.05-3.5 millimeter that this product has average micro-pore diameter, density is 16-80 kilogram/rice
3(1.0-5.0 pound/cubic feet), minimum cross-section thickness are that 1.3 centimetres (0.5 inches) and smallest cross-section area are 52 centimetres
2(8 inches
2).
4, according to the process of claim 1 wherein that alkenyl aromatic synthetic resins is polystyrene.
5, according to the process of claim 1 wherein that alkenyl aromatic synthetic resins is styrene/acrylic acid co-polymer, contain 0.1 to 15%(weight in the total resin weight) polymeric vinylformic acid.
6, according to the process of claim 1 wherein that alkenyl aromatic synthetic resins is the styrene/acrylic ionic crosslinking copolymer.
7, according to the method for claim 6, wherein this ion is selected from calcium, sodium, lithium, potassium, magnesium and these ionic mixtures.
8, according to the method for claim 7, the ion of wherein supplying with the ionomer styrene/acrylic acid co-polymer is to be percent 0.1 neutralizing agents to 1 part of weight by add per 100 parts of weight resins in the thermoplastification resin in step (a), and these neutralizing agents are selected from the mixture of calcium hydroxide, lithium hydroxide, sodium hydroxide, potassium hydroxide, magnesium oxide and these compounds.
9, method according to Claim 8, the amount of the neutralizing agent of wherein said adding are that per 100 parts of weight resins are percent 0.1 to 0.6 part.
10, according to the method for claim 1, step (a) afterwards and step (b) before, also comprise the thermoplastification resin by this step of pressure control device.
11, according to the process of claim 1 wherein the reduction of proofreading and correct △ P value by following method:
(a) temperature of reduction mixing device;
(b) part is closed in the throttling valve between mixing device and the die entrance;
(c) reduce density of foaming agent; And/or
(d) improve the input speed that alkenyl aromatic synthetic resins enters mixing device.
12, require the method for any one claim among the 1-11 according to aforesaid right, METHOD FOR CONTINUOUS DETERMINATION △ P value wherein is whenever △ P value drops to the preset value signal that just gives the alarm automatically when following.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 88108435 CN1025678C (en) | 1988-10-14 | 1988-10-14 | Preparation of styrene polymer foam and product |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 88108435 CN1025678C (en) | 1988-10-14 | 1988-10-14 | Preparation of styrene polymer foam and product |
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|---|---|
| CN1041960A CN1041960A (en) | 1990-05-09 |
| CN1025678C true CN1025678C (en) | 1994-08-17 |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| US7144532B2 (en) * | 2002-10-28 | 2006-12-05 | Trexel, Inc. | Blowing agent introduction systems and methods |
| CA2628473C (en) * | 2005-11-30 | 2014-07-22 | Lg Chem, Ltd. | Microcellular foam of thermoplastic resin prepared with die having improved cooling property and method for preparing the same |
| CN102658620B (en) * | 2012-05-07 | 2014-03-26 | 青岛海信模具有限公司 | Method for improving surface quality of foam molded plastic part |
| KR102265615B1 (en) * | 2013-12-12 | 2021-06-16 | 다이아비 인터내셔널 에이비 | Apparatus and method for the production of expanded foam embryos |
-
1988
- 1988-10-14 CN CN 88108435 patent/CN1025678C/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| CN1041960A (en) | 1990-05-09 |
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