# US 11,993,669 B2 · Foamable resin particles and method of producing same, and foamed molded body

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- Number: US 11,993,669 B2
- Document ID: US11993669B2
- Status: Granted
- Kind: B2
- Application number: 17/170,101
- Filed: 2021-02-08
- Published: 2021-06-03
- Granted: 2024-05-28
- Earliest claimed: 2018-08-09
- Assignees: Kaneka Corporation
- Applicants: Kaneka Corporation
- Inventors: Atsushi Iida; Mitsuhiro Tamura; Yoichi Ohara
- Web page: https://patentgrep.com/patent/US11993669B2

## CPC

- C08F 212/10: with nitriles
- C08J 9/232: by sintering expandable particles
- C08F 212/08: Styrene
- C08J 9/141: {Hydrocarbons}
- C08J 9/18: by impregnating polymer particles with the blowing agent
- C08J 2201/034: Post-expanding of foam beads or sheets
- C08J 2203/10: Water or water-releasing compounds
- C08J 2203/14: Saturated hydrocarbons, e.g. butane; Unspecified hydrocarbons
- C08J 2325/12: with unsaturated nitriles
- C08F: MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
- 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)

## Abstract

Expandable resin particles that have a reduced VOC content, a method of producing the expandable resin particles, and a foamed molded product that has reduced VOC emission are provided. The expandable resin particles contain a base material resin containing, as a structural unit, a styrene unit and an acrylonitrile unit and an expanding agent. The expandable resin particles have a styrene content and an ethylbenzene content each of which is not more than a specific amount.

## Claims

### Claim 1

Expandable resin particles comprising:
a base material resin containing, as a structural unit, a styrene unit and an acrylonitrile unit; and an expanding agent,
wherein the expandable resin particles have a styrene content of not more than 20 ppm and an ethylbenzene content of not more than 130 ppm, and
wherein the base material resin has a TH/TQ ratio of less than 1.20.

### Claim 2 (depends on 1)

The expandable resin particles as set forth in claim 1, wherein:
(a) the base material resin further contains an alpha-methylstyrene unit as a structural unit;
(b) an amount of the styrene unit in the base material resin is not less than 60 parts by weight and not more than 75 parts by weight, an amount of the acrylonitrile unit in the base material resin is not less than 21 parts by weight and not more than 27 parts by weight, and an amount of the alpha-methylstyrene unit in the base material resin is not less than 3 parts by weight and not more than 15 parts by weight; and
(c) a total amount of the styrene unit, the acrylonitrile unit, and the alpha-methylstyrene unit in the base material resin is 100 parts by weight.

### Claim 3 (depends on 1)

The expandable resin particles as set forth in claim 1, wherein the expandable resin particles have a water content of not less than 1%.