# US 11,027,466 B2 · Process for producing foam molded parts with aesthetic surfaces by foam injection molding

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 11,027,466 B2
- Document ID: US11027466B2
- Status: Granted
- Kind: B2
- Application number: 16/061,922
- Filed: 2016-12-13
- Published: 2020-08-20
- Granted: 2021-06-08
- Earliest claimed: 2015-12-17
- Assignees: Ineos Styrolution Group GmbH
- Applicants: Ineos Styrolution Group GmbH
- Inventors: Bastian Raithel; Norbert Niessner; Achim Bernhardt; Stefan Roettel; Pierre Juan; Andreas Popp
- Web page: https://patentgrep.com/patent/US11027466B2

## CPC

- B29C 44/3446: {Feeding the blowing agent}
- C08J 9/0061: {characterized by the use of several polymeric components}
- B29C 44/3415: {Heating or cooling}
- B29C 44/348: {by regulating the temperature and/or the pressure, e.g. suppression of foaming until the pressure is rapidly decreased}
- B29C 44/42: using pressure difference, e.g. by injection or by vacuum
- C08J 9/08: developing carbon dioxide
- C08J 9/122: {Hydrogen, oxygen, CO2, nitrogen or noble gases}
- C08L 55/02: ABS [Acrylonitrile-Butadiene-Styrene] polymers
- B29K 2055/02: ABS polymers, i.e. acrylonitrile-butadiene-styrene polymers
- C08J 2203/02: CO2-releasing, e.g. NaHCO3 and citric acid
- C08J 2203/06: CO2, N2 or noble gases
- C08J 2351/04: grafted on to rubbers
- C08J 2355/02: Acrylonitrile-Butadiene-Styrene [ABS] polymers
- C08J 2469/00: Characterised by the use of polycarbonates; Derivatives of polycarbonates
- C08J 2477/00: Characterised by the use of polyamides obtained by reactions forming a carboxylic amide link in the main chain; Derivatives of such polymers
- B29C: SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING (making preforms B29B11/00; making laminated products by combining previously unconnected layers which become one product whose layers will remain together B32B37/00 - B32B41/00)
- C08J: WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H (working, e.g. shaping, of plastics B29)
- C08L: COMPOSITIONS OF MACROMOLECULAR COMPOUNDS (compositions based on polymerisable monomers C08F, C08G; artificial filaments or fibres D01F; textile treating compositions D06)
- B29K: INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR {MOULDS, } REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS

## Abstract

The invention relates to a process for producing a foam molded part, wherein a foamable material S comprising a thermoplastic polymer matrix M and at least one foaming agent F is foamed by foam injection molding. The polymer matrix M is preferably based on at least one thermoplastic styrene copolymer, such as ABS and ASA, and wherein the at least one foaming agent F is selected from chemical foaming agents, releasing carbon dioxide, and physical foaming agents, being carbon dioxide or nitrogen.

## Claims

### Claim 1

A process for producing a foam molded part by foam injection molding, which comprises the following steps:
a) providing a melt of a foamable material S comprising a thermoplastic polymer matrix M and at least one foaming agent F selected from chemical foaming agents releasing carbon dioxide and physical foaming agents selected from nitrogen and carbon dioxide,
wherein the thermoplastic polymer matrix M comprises at least one thermoplastic styrene copolymer P consisting of, based on P:
1.1 5-95% by weight of a copolymer A consisting of, based on A:
1.1.1 70-76% by weight, of one or more vinyl aromatic monomer(s) A1 selected from styrene and substituted styrenes,
1.1.2 24-30% by weight, of one or more vinyl cyanide monomer(s) A2 selected from acrylonitrile, methacrylonitrile, or mixtures thereof, and
1.1.3 0-6% by weight, of one or more unsaturated copolymerizable monomers A3,
1.2 5-60% by weight of a graft rubber B consisting of, based on B:
1.2.1 10-95% by weight of a graft base B1 comprising, based on B1:
1.2.1.1 80-100% by weight of one or more rubber type monomer(s) B11 selected from butadiene, isoprene, and C1-C10 alkyl acrylates, and
1.2.1.2 0-20% by weight of one or more polyfunctional crosslinking monomer(s) B12, and
1.2.2 5-90% by weight of a graft shell B2 comprising, based on B2:
1.2.2.1 75-85% by weight of one or more vinyl aromatic monomer(s) B21 selected from styrene and substituted styrenes,
1.2.2.2 15-25% by weight of one or more vinyl cyanide monomer(s) B22 selected from acrylonitrile, methacrylonitrile, or mixtures thereof, and
1.2.2.3 0-10% by weight of one or more unsaturated copolymerizable monomers B23;
b) filling a mold cavity K with the melt of the foamable material S by injection;
c) foaming the foamable material S in the mold cavity K by reduction of pressure and/or increase in temperature;
d) taking out the foam molded part; and
e) optionally further working of the foam molded part;
wherein the melt temperature shortly before or during injection of the melt into the mold cavity in step b) is in the range of 255° C. to 300° C., and wherein the mold temperature in step b) is in the range of 50° C. to 150° C., and
wherein filling of the mold cavity K with the melt of the foamable material S by injection in step b) is carried out with an injection speed in the range of 100 to 200 ccm/s.

### Claim 2 (depends on 1)

The process according to claim 1, wherein the foamable material S comprises as further additive one or more additives selected from fillers, plasticizers, impact modifiers, dyes, pigments, colorants, flame retardants, antistatic agents, mold-release agents, antioxidants, stabilizers, and lubricants.

### Claim 3 (depends on 1)

The process according to claim 1, wherein the vinyl aromatic monomer(s) A1 and/or B21 are selected from styrene, substituted styrenes of the formula I:
wherein:
R is C1-C8-alkyl or hydrogen,
R1 is C1-C8-alkyl or hydrogen,
with the provision that not both R and R1 are hydrogen, and
n is 1, 2, or 3,
and mixtures of these compounds.

### Claim 4 (depends on 1)

The process according to claim 1, wherein the thermoplastic polymer matrix M consists of a blend of at least one thermoplastic styrene copolymer P and at least one further polymer selected from polycarbonates and polyamides.

### Claim 5 (depends on 1)

The process according to claim 1, wherein the foamable material S comprises at least 0.1% by weight, based on the foamable material S, of a chemical foaming agent comprising bicarbonate and citric acid as sole foaming agent.

### Claim 6 (depends on 1)

The process according to claim 1, wherein the melt temperature shortly before or during injection of the melt into the mold cavity in step b) is equal or higher than 270° C., and wherein the mold temperature in step b) is equal or higher than 70° C.

### Claim 7 (depends on 1)

The process according to claim 1, wherein the melt temperature shortly before or during injection of the melt into the mold cavity in step b) is in the range of 265° C. to 290° C., and wherein the mold temperature in step b) is in the range of 50° C. to 100° C.

### Claim 8 (depends on 1)

The process according to claim 1, wherein filing of the mold cavity K with the melt of the foamable material S by injection in step b) is carried out with an injection speed in the range of 150 to 180 ccm/s.

### Claim 9 (depends on 1)

The process according to claim 1, wherein the mold cavity K exhibits a polished surface or a grained surface having grain domains of at least 10 μm.

### Claim 10 (depends on 1)

The process according to claim 1, wherein the thermoplastic polymer matrix M consists of at least one polymer selected from acrylonitrile-butadiene-styrene copolymers, acrylonitrile-styrene-acrylate copolymers, and blends of said styrene copolymers with at least one polyamide.

### Claim 11 (depends on 1)

The process according to claim 1, wherein the foaming in step c) is carried out by reduction of pressure and wherein the reduction of pressure and the foaming is performed together with the injection step b).

### Claim 12 (depends on 1)

The process according to claim 1, wherein the foaming of the foamable material S in step c) results in a density reduction in the range of 5 to 20%.

### Claim 13 (depends on 1)

The process according to claim 1, wherein the thermoplastic polymer matrix M consists of acrylonitrile-butadiene-styrene copolymers, acrylonitrile-styrene-acrylate copolymers, or blends of acrylonitrile-butadiene-styrene copolymer and at least one polyamide, wherein the melt temperature shortly before or during injection of the melt into the mold cavity in step b) is in the range of 265° C. to 290° C.; wherein the mold temperature in step b) is in the range of 70 to 90° C.; and wherein the foaming of the foamable material S in step c) results in a density reduction in the range of 7 to 18%.