CA2165037A1 - Polystyrene particule foams of reduced water absorption capacity - Google Patents
Polystyrene particule foams of reduced water absorption capacityInfo
- Publication number
- CA2165037A1 CA2165037A1 CA002165037A CA2165037A CA2165037A1 CA 2165037 A1 CA2165037 A1 CA 2165037A1 CA 002165037 A CA002165037 A CA 002165037A CA 2165037 A CA2165037 A CA 2165037A CA 2165037 A1 CA2165037 A1 CA 2165037A1
- Authority
- CA
- Canada
- Prior art keywords
- polystyrene
- fluorocarbon
- water absorption
- absorption capacity
- styrene
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
- C08J9/00—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof
- C08J9/16—Making expandable particles
- C08J9/18—Making expandable particles by impregnating polymer particles with the blowing agent
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
- C08L25/00—Compositions of, homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by an aromatic carbocyclic ring; Compositions of derivatives of such polymers
- C08L25/02—Homopolymers or copolymers of hydrocarbons
- C08L25/04—Homopolymers or copolymers of styrene
Landscapes
- Chemical & Material Sciences (AREA)
- Health & Medical Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Medicinal Chemistry (AREA)
- Polymers & Plastics (AREA)
- Organic Chemistry (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Manufacture Of Porous Articles, And Recovery And Treatment Of Waste Products (AREA)
Abstract
The invention relates to polystyrene particle foams of reduced water absorption capacity, obtainable by foaming expandable styrene polymers in a manner known per se, wherein the poly-styrene particles are treated with at least one fluorocarbon compound.
Description
216~0~7 Polystyrene particle foams of reduced water absorption capacity The present invention relates to polystyrene particle foams of reduced water absorption capacity.
Plastics based on styrene and styrene-containing copolymers are produced in large volumes and are used in many areas of industry.
Foamed products are also of considerable importance here.
The preparation and use of these products has been known for some time and has been described in numerous publications.
In many areas of application of polystyrene foams, for example roof insulation, perimeter insulation and fish crates, the foams are exposed to the action of water this may result in penetra-tion of moisture into the interior of the foam, which is disadvantageous in these applications and should be prevented if possible.
Water absorption by sheets and moldings made from polystyrene particle foam has hitherto usually been prevented or reduced by applying a plastic film or coating the finished moldings. How-ever, this requires an additional step, and in addition this coating is frequently not uniform over the entire molding in the case of complex shapes.
Another way of minimizing the ingress of water into moldings made from polystyrene particle foam is to keep the volume between the 30 foam particles as small as possible. This can be achieved by increasing the pressure and temperature of the steam used for expansion.
However, this has the disadvantage of increasing the molding production time and, where the temperature is increased, of resulting in increased energy consumption in molding production.
It is an object of the present invention to develop a polystyrene particle foam of reduced water absorption capacity which can be 40 produced simply and without additional steps.
We have found that, surprisingly, this object is achieved by a polystyrene particle foam which is obtainable by foaming an expandable styrene bead polymer and treating the latter with a fluorocarbon compound after the polymerization, work-up or pre-foaming.
2l6~n37 The present invention accordingly provides a polystyrene particle foam, obtainable by foaming an expandable styrene bead polymer, which is treated with a fluorocarbon compound after the polymeri-zation, work-up or prefoaming, and moldings produced from this polystyrene particle foam.
The present invention furthermore provides an expandable styrene polymer treated with a fluorocarbon compound after the polymeri-zation and work-up.
The present invention furthermore provides moldings made from a polystyrene particle foam which are surface-treated with a fluorocarbon compound after the shaping.
The fluorocarbon compound employed is, according to the inven-tion, a fluorocarbon resin, in particular a polyfluoroalkyl (meth)acrylate, such as polyfluorooctyl acrylate.
Also advantageous are compounds as employed as oil repellents in 20 the textile industry, for example Persistol~ 0 from 8ASF
Aktiengesellschaft. A more detaile~ description of these com-pounds is given, for example, in Ullmanns Encyklopadie der technischen Chemie, Urban & Schwarzenberg, Munich, Berlin, Vienna, 3rd Edition, 1966, Volume 17, page 203 ff.
The fluorocarbon compounds used in accordance with the invention are usually in the form of an emulsion. For example, Persistol~ 0 is sold as a cationic aqueous emulsion. This is advantageous for the novel treatment of polystyrene beads, since any interactions 30 of the polymer with solvents can be excluded in this way.
The content of the fluorocarbon compounds in the emulsion is from about 15 to 20 ~ by weight, based on the weight of the emulsion.
This concentration range is advantageous for the novel procedure, since lower contents can result in incomplete coating of the beads, and higher contents can mean instability of the emulsion.
The treatment with the fluorocarbon compounds can be carried out directly after work-up and drying of the polystyrene beads.
However, it is advantageous to carry out the treatment with the fluorocarbon compounds after prefoaming of the polystyrene beads.
This gives better distribution of the fluorocarbon compounds over the surface of the polystyrene beads.
' 2l6sn~7 The amount of fluorocarbon compounds and their contact time with the polystyrene beads should give complete wetting of the beads.
The time necessary to accomplish this can easily be determined by preliminary experiments.
The wetting of the beads with the fluorocarbon compounds can be carried out, for example, in a bath or by spraying the beads.
After treatment of the polystyrene beads with the fluorocarbon 10 compounds, the beads must be dried. This is usually carried out using air at room temperature or slightly elevated temperature, but this temperature must, in the case of treatment of unfoamed polystyrene beads, be sufficiently far below the softening point of the polystyrene beads that unintended expansion of the beads and escape of the blowing agent are prevented.
It is furthermore possible in accordance with the invention to reduce the water absorption capacity of moldings made from poly-styrene particle foams by treating the surface of the moldings 20 with the fluorocarbon compounds employed in accordance with the invention. Again, the fluorocarbon compounds should be in liquefied form, usually in the form of an emulsion. In this type of treatment, the molding is usually immersed in the emulsion containing the fluorocarbon compounds and is subsequently dried in air.
The polystyrene bead polymers employed for the preparation of the novel polystyrene particle foams of reduced water absorption capacity are prepared by conventional processes known per se. To 30 this end, the monomeric styrene, if desired mixed with other olefinically unsaturated comonomers, catalysts, auxiliaries and additives, is suspended in water and polymerized, usually in the presence of suspension stabilizers. The resultant polystyrene beads are separated off, washed and dried.
The blowing agent can be added during the polymerization, but it is also possible to introduce the blowing agent into the poly-styrene beads in a subsequent step.
40 After impregnation with the blowing agent, the polystyrene beads are usually coated. The coating agents are selected, for example, with a view to reducing stickiness and electrostatic charging of the beads.
2165~37 Examples of coating agents used are esters of glycerol and fatty acids, metal stearates and silicic acid. The coating of the poly-styrene beads is predominantly carried out mechanically, for example in drum mixers.
The foaming of the polystyrene beads containing blowing agent to give foams is likewise usually carried out by processes known from the prior art by first prefoaming the polystyrene beads con-taining blowing agent using steam in open or closed prefoamers.
10 The prefoamed beads are then welded together in gas-permeable molds by means of steam to give moldings or sheets.
The novel treatment with the fluorocarbon compounds is carried out before or after the prefoaming or after molding production.
Further details on conventional polymerization, impregnation and foaming processes are given, for example, in Kunststoffhandbuch, Volume 5, Polystyrene, edited by R. Vieweg and G. Daumiller, Carl-Hanser-Verlag, Munich, 1969.
Surprisingly, the novel treatment with the fluorocarbon compounds has no adverse effects on the mechanical and processing proper-ties of the styrene polymers. Neither are the demolding times increased.
The novel treatment greatly reduces the water absorption capacity of the styrene polymers. Moldings made from polystyrene beads treated in this way can also be employed for applications in which they are constantly exposed to water, for example for roof 30 insulation, perimeter insulation and fish crates.
The novel process is very simple and inexpensive. The fluoro-carbon compounds employed in accordance with the invention are readily available, readily compatible with the styrene polymers and do not impair the properties of the polystyrene foams.
The invention is described in greater detail with reference to the examples below:
40 Example 1 124 g of expandable polystyrene in bead form having a mean bead diameter of 0.9 mm were prefoamed for 2 minutes to a density of 35 g/l in a Rauscher-type pressureless foaming box. After interim storage for 24 hours, the prefoamed beads were immersed for 15 minutes in a bath containing a 17 % strength aqueous emulsion of ~ASF Persistol~ 0 which had been adjusted to a pH of 4 by 216~037 means of acetic acid. The beads were then dried by means of cold air, introduced into a mold having a thickness of 5 cm and a diameter of 25 cm and welded together by means of steam to give a molding. The fluorine content of the molding was 0.22 g/100 g.
In order to determine the water absorption capacity, a water column with a diameter of 10 cm and a height of 10 cm was allowed to act on the molding. After 24 hours, the water level had dropped by 2 mm.
Example 2 (comparison) The procedure was similar to that of Example 1, but treatment with the aqueous emulsion of ~ASF Persistol~ 0 was omitted.
In order to determine the water absorption capacity, a water column with a diameter of 10 cm and a height of 10 cm was allowed to act on the molding. After 24 hours the water level had dropped by 40 mm.
Example 3 127 g of an expandable polystyrene in bead form having a mean bead diameter of 0.9 mm were immersed for 15 minutes in a bath containing a 17 ~ strength aqueous emulsion of ~ASF Persistol~ 0 which had been adjusted to pH 4 by means of acetic acid.
The expandable polystyrene beads were then removed using a sieve, allowed to drip for 5 minutes and dried in a stream of cold air.
The beads treated in this way were prefoamed to a density of 36 g/l in a Rauscher-type pressureless foaming box. After interim storage for 24 hours, the beads were introduced into a mold having a thickness of 5 cm and a diameter of 25 cm and welded together by means of steam to give a molding.
The water absorption capacity of the foam was determined as described in Example 1.
40 After 72 hours, the water level had dropped by 4 mm.
Example 4 (comparison) The procedure was similar to that of Example 3, but treatment with the aqueous emulsion of ~ASF Persistol~ 0 was omitted.
216~037 The water absorption capacity of the foam was determined as described in Example 1.
After 72 hours, the water level had dropped by 40 mm.
Plastics based on styrene and styrene-containing copolymers are produced in large volumes and are used in many areas of industry.
Foamed products are also of considerable importance here.
The preparation and use of these products has been known for some time and has been described in numerous publications.
In many areas of application of polystyrene foams, for example roof insulation, perimeter insulation and fish crates, the foams are exposed to the action of water this may result in penetra-tion of moisture into the interior of the foam, which is disadvantageous in these applications and should be prevented if possible.
Water absorption by sheets and moldings made from polystyrene particle foam has hitherto usually been prevented or reduced by applying a plastic film or coating the finished moldings. How-ever, this requires an additional step, and in addition this coating is frequently not uniform over the entire molding in the case of complex shapes.
Another way of minimizing the ingress of water into moldings made from polystyrene particle foam is to keep the volume between the 30 foam particles as small as possible. This can be achieved by increasing the pressure and temperature of the steam used for expansion.
However, this has the disadvantage of increasing the molding production time and, where the temperature is increased, of resulting in increased energy consumption in molding production.
It is an object of the present invention to develop a polystyrene particle foam of reduced water absorption capacity which can be 40 produced simply and without additional steps.
We have found that, surprisingly, this object is achieved by a polystyrene particle foam which is obtainable by foaming an expandable styrene bead polymer and treating the latter with a fluorocarbon compound after the polymerization, work-up or pre-foaming.
2l6~n37 The present invention accordingly provides a polystyrene particle foam, obtainable by foaming an expandable styrene bead polymer, which is treated with a fluorocarbon compound after the polymeri-zation, work-up or prefoaming, and moldings produced from this polystyrene particle foam.
The present invention furthermore provides an expandable styrene polymer treated with a fluorocarbon compound after the polymeri-zation and work-up.
The present invention furthermore provides moldings made from a polystyrene particle foam which are surface-treated with a fluorocarbon compound after the shaping.
The fluorocarbon compound employed is, according to the inven-tion, a fluorocarbon resin, in particular a polyfluoroalkyl (meth)acrylate, such as polyfluorooctyl acrylate.
Also advantageous are compounds as employed as oil repellents in 20 the textile industry, for example Persistol~ 0 from 8ASF
Aktiengesellschaft. A more detaile~ description of these com-pounds is given, for example, in Ullmanns Encyklopadie der technischen Chemie, Urban & Schwarzenberg, Munich, Berlin, Vienna, 3rd Edition, 1966, Volume 17, page 203 ff.
The fluorocarbon compounds used in accordance with the invention are usually in the form of an emulsion. For example, Persistol~ 0 is sold as a cationic aqueous emulsion. This is advantageous for the novel treatment of polystyrene beads, since any interactions 30 of the polymer with solvents can be excluded in this way.
The content of the fluorocarbon compounds in the emulsion is from about 15 to 20 ~ by weight, based on the weight of the emulsion.
This concentration range is advantageous for the novel procedure, since lower contents can result in incomplete coating of the beads, and higher contents can mean instability of the emulsion.
The treatment with the fluorocarbon compounds can be carried out directly after work-up and drying of the polystyrene beads.
However, it is advantageous to carry out the treatment with the fluorocarbon compounds after prefoaming of the polystyrene beads.
This gives better distribution of the fluorocarbon compounds over the surface of the polystyrene beads.
' 2l6sn~7 The amount of fluorocarbon compounds and their contact time with the polystyrene beads should give complete wetting of the beads.
The time necessary to accomplish this can easily be determined by preliminary experiments.
The wetting of the beads with the fluorocarbon compounds can be carried out, for example, in a bath or by spraying the beads.
After treatment of the polystyrene beads with the fluorocarbon 10 compounds, the beads must be dried. This is usually carried out using air at room temperature or slightly elevated temperature, but this temperature must, in the case of treatment of unfoamed polystyrene beads, be sufficiently far below the softening point of the polystyrene beads that unintended expansion of the beads and escape of the blowing agent are prevented.
It is furthermore possible in accordance with the invention to reduce the water absorption capacity of moldings made from poly-styrene particle foams by treating the surface of the moldings 20 with the fluorocarbon compounds employed in accordance with the invention. Again, the fluorocarbon compounds should be in liquefied form, usually in the form of an emulsion. In this type of treatment, the molding is usually immersed in the emulsion containing the fluorocarbon compounds and is subsequently dried in air.
The polystyrene bead polymers employed for the preparation of the novel polystyrene particle foams of reduced water absorption capacity are prepared by conventional processes known per se. To 30 this end, the monomeric styrene, if desired mixed with other olefinically unsaturated comonomers, catalysts, auxiliaries and additives, is suspended in water and polymerized, usually in the presence of suspension stabilizers. The resultant polystyrene beads are separated off, washed and dried.
The blowing agent can be added during the polymerization, but it is also possible to introduce the blowing agent into the poly-styrene beads in a subsequent step.
40 After impregnation with the blowing agent, the polystyrene beads are usually coated. The coating agents are selected, for example, with a view to reducing stickiness and electrostatic charging of the beads.
2165~37 Examples of coating agents used are esters of glycerol and fatty acids, metal stearates and silicic acid. The coating of the poly-styrene beads is predominantly carried out mechanically, for example in drum mixers.
The foaming of the polystyrene beads containing blowing agent to give foams is likewise usually carried out by processes known from the prior art by first prefoaming the polystyrene beads con-taining blowing agent using steam in open or closed prefoamers.
10 The prefoamed beads are then welded together in gas-permeable molds by means of steam to give moldings or sheets.
The novel treatment with the fluorocarbon compounds is carried out before or after the prefoaming or after molding production.
Further details on conventional polymerization, impregnation and foaming processes are given, for example, in Kunststoffhandbuch, Volume 5, Polystyrene, edited by R. Vieweg and G. Daumiller, Carl-Hanser-Verlag, Munich, 1969.
Surprisingly, the novel treatment with the fluorocarbon compounds has no adverse effects on the mechanical and processing proper-ties of the styrene polymers. Neither are the demolding times increased.
The novel treatment greatly reduces the water absorption capacity of the styrene polymers. Moldings made from polystyrene beads treated in this way can also be employed for applications in which they are constantly exposed to water, for example for roof 30 insulation, perimeter insulation and fish crates.
The novel process is very simple and inexpensive. The fluoro-carbon compounds employed in accordance with the invention are readily available, readily compatible with the styrene polymers and do not impair the properties of the polystyrene foams.
The invention is described in greater detail with reference to the examples below:
40 Example 1 124 g of expandable polystyrene in bead form having a mean bead diameter of 0.9 mm were prefoamed for 2 minutes to a density of 35 g/l in a Rauscher-type pressureless foaming box. After interim storage for 24 hours, the prefoamed beads were immersed for 15 minutes in a bath containing a 17 % strength aqueous emulsion of ~ASF Persistol~ 0 which had been adjusted to a pH of 4 by 216~037 means of acetic acid. The beads were then dried by means of cold air, introduced into a mold having a thickness of 5 cm and a diameter of 25 cm and welded together by means of steam to give a molding. The fluorine content of the molding was 0.22 g/100 g.
In order to determine the water absorption capacity, a water column with a diameter of 10 cm and a height of 10 cm was allowed to act on the molding. After 24 hours, the water level had dropped by 2 mm.
Example 2 (comparison) The procedure was similar to that of Example 1, but treatment with the aqueous emulsion of ~ASF Persistol~ 0 was omitted.
In order to determine the water absorption capacity, a water column with a diameter of 10 cm and a height of 10 cm was allowed to act on the molding. After 24 hours the water level had dropped by 40 mm.
Example 3 127 g of an expandable polystyrene in bead form having a mean bead diameter of 0.9 mm were immersed for 15 minutes in a bath containing a 17 ~ strength aqueous emulsion of ~ASF Persistol~ 0 which had been adjusted to pH 4 by means of acetic acid.
The expandable polystyrene beads were then removed using a sieve, allowed to drip for 5 minutes and dried in a stream of cold air.
The beads treated in this way were prefoamed to a density of 36 g/l in a Rauscher-type pressureless foaming box. After interim storage for 24 hours, the beads were introduced into a mold having a thickness of 5 cm and a diameter of 25 cm and welded together by means of steam to give a molding.
The water absorption capacity of the foam was determined as described in Example 1.
40 After 72 hours, the water level had dropped by 4 mm.
Example 4 (comparison) The procedure was similar to that of Example 3, but treatment with the aqueous emulsion of ~ASF Persistol~ 0 was omitted.
216~037 The water absorption capacity of the foam was determined as described in Example 1.
After 72 hours, the water level had dropped by 40 mm.
Claims (10)
1. A polystyrene particle foam having a reduced water absorption capacity, obtainable by foaming an expandable styrene polymer in a manner known per se, wherein the polystyrene particles are treated with at least one fluorocarbon compound.
2. A polystyrene particle foam as claimed in claim 1, wherein the styrene bead polymer is treated with at least one fluoro-carbon compound after prefoaming.
3. A polystyrene particle foam as claimed in claim 1 or 2, wherein the fluorocarbon compound employed is a fluorocarbon resin.
4. An expandable styrene bead polymer as claimed in any of claims 1 to 3, wherein the polystyrene particles containing blowing agent are treated with at least one fluorocarbon com-pound after polymerization, drying and work-up.
5. An expandable styrene bead polymer as claimed in any of claims 1 to 4, wherein the fluorocarbon compound is in the form of an emulsion.
6. An expandable styrene bead polymer as claimed in any of claims 1 to 5, wherein the fluorocarbon compound is in the form of an aqueous emulsion.
7. A process for the preparation of expandable styrene bead polymers which can be converted into polystyrene particle foams of reduced water absorption capacity, by polymeriza-tion, known per se, of styrene, if desired mixed with other olefinically unsaturated monomers, impregnation of the polymers with blowing agent during or after the polymeriza-tion, and conventional work-up of the beads, which comprises treating the polystyrene particles with at least one fluoro-carbon compound.
8. A process as claimed in claim 7, wherein the treatment of the styrene polymers with the fluorocarbon compound is carried out by spraying.
9. A process as claimed in claim 7, wherein the treatment of the styrene polymers with the fluorocarbon compound is carried out by immersion.
10. A process for the preparation of polystyrene particle foams of reduced water absorption capacity by the preparation, known per se, of expandable styrene polymers, followed by work-up, drying and coating, and impregnation of the pre-foamed polystyrene particles with at least one fluorocarbon compound.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DEP4445210.1 | 1994-12-17 | ||
| DE4445210 | 1994-12-17 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2165037A1 true CA2165037A1 (en) | 1996-06-18 |
Family
ID=6536215
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002165037A Abandoned CA2165037A1 (en) | 1994-12-17 | 1995-12-12 | Polystyrene particule foams of reduced water absorption capacity |
Country Status (2)
| Country | Link |
|---|---|
| KR (1) | KR960022765A (en) |
| CA (1) | CA2165037A1 (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1997043334A1 (en) * | 1996-05-14 | 1997-11-20 | Basf Aktiengesellschaft | Expandable polystyrene particles |
| EP0913423A2 (en) * | 1997-10-28 | 1999-05-06 | Basf Aktiengesellschaft | Coated expansible styrene polymer beads |
-
1995
- 1995-12-12 CA CA002165037A patent/CA2165037A1/en not_active Abandoned
- 1995-12-15 KR KR1019950050348A patent/KR960022765A/en not_active Application Discontinuation
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1997043334A1 (en) * | 1996-05-14 | 1997-11-20 | Basf Aktiengesellschaft | Expandable polystyrene particles |
| CN1070207C (en) * | 1996-05-14 | 2001-08-29 | 巴斯福股份公司 | Expandable polystyrene particles |
| EP0913423A2 (en) * | 1997-10-28 | 1999-05-06 | Basf Aktiengesellschaft | Coated expansible styrene polymer beads |
| EP0913423A3 (en) * | 1997-10-28 | 2000-12-27 | Basf Aktiengesellschaft | Coated expansible styrene polymer beads |
Also Published As
| Publication number | Publication date |
|---|---|
| KR960022765A (en) | 1996-07-18 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| FZDE | Dead |