Expandable acrylic resin bead, expanded acrylic resin bead, and expanded acrylic resin beads molded article

Patent metadata

Field	Value
Publication number	US-10377873-B2
Application number	US-201615554842-A
Country	US
Kind code	B2
Filing date	Mar 1, 2016
Priority date	Mar 2, 2015
Publication date	Aug 13, 2019
Grant date	Aug 13, 2019

Abstract

Provided are an expanded acrylic resin beads molded article that produces little soot during burning, and has good castabilities and high strength, and an expandable acrylic resin bead and an expanded acrylic resin bead for producing the expanded acrylic resin beads molded article. The expandable acrylic resin bead includes a physical blowing agent and a copolymer. The copolymer is composed of a methyl methacrylate component, an acrylic acid ester component, and a styrene component in a predetermined proportion. The copolymer constitutes a base resin of the expandable acrylic resin beads. The water content of the expandable acrylic resin bead is a 0.5 mass % or less. The expanded acrylic resin bead includes the copolymer and has a bulk density and cell diameters within predetermined ranges, and the expanded acrylic resin beads molded article is produced by in-mold molding of plural expanded beads.

First claim

The invention claimed is:

1. An expandable acrylic resin bead comprising:
a physical blowing agent; and
a base resin comprising a copolymer comprising 50 to 79 mol % of a methyl methacrylate component, 1 to 10 mol % of an acrylic acid ester component, and 20 to 40 mol % of a styrene component,
wherein the acrylic acid ester component comprises at least one selected from the group consisting of butyl acrylate, ethyl acrylate, and methyl acrylate;
wherein a total content of the methyl methacrylate component, the acrylic acid ester component, and the styrene component amounts to 100 mol %;
wherein the expandable acrylic resin bead has a water content of 0.05 to 0.4 mass % and a content of a volatile component of 5 to 10 mass %, and
wherein a molar ratio of a total amount of the acrylic acid ester component and the methyl methacrylate component to an amount of the styrene component is in a range of 2 to 3.8.

2. The expandable acrylic resin bead according to claim 1 , wherein a molar ratio of a total amount of the acrylic acid ester component and the methyl methacrylate component to an amount of the styrene component is in a range of 2.2 to 3.5.

3. The expandable acrylic resin bead according to claim 1 , wherein the copolymer has a weight-average molecular weight of 50000 to 300000.

4. The expandable acrylic resin bead according to claim 1 , wherein the copolymer consists essentially of the methyl methacrylate component, the acrylic acid ester component, and the styrene component.

Assignees

• Jsp Corp

Inventors

• KUWADA Yohta
• Murata Mitsushi

Classifications

• B29K2033/12

  Polymers of methacrylic acid esters, e.g. PMMA, i.e. polymethylmethacrylate · CPC title

• B29K2105/0085

  Copolymers · CPC title

• C08J9/232

  by sintering expandable particles · CPC title

• C08J9/141

  Hydrocarbons · CPC title

• B29K2105/041

  Microporous · CPC title