Thermally expandable microcapsule, method for producing thermally expandable microcapsule, foamable masterbatch, and foam molded article

Patent metadata

Field	Value
Publication number	US-9776157-B2
Application number	US-201113637216-A
Country	US
Kind code	B2
Filing date	Mar 3, 2011
Priority date	Mar 31, 2010
Publication date	Oct 3, 2017
Grant date	Oct 3, 2017

Abstract

The present invention provides a thermally expandable microcapsule that is excellent in heat resistance and durability and exhibits an excellent foaming property in a wide temperature range from low temperatures to high temperatures. The present invention is a thermally expandable microcapsule, which comprises a shell containing a copolymer, and a volatile liquid as a core agent included in the shell, the copolymer being obtainable by polymerization of a monomer mixture containing a monomer A and a monomer B, the monomer A being at least one selected from the group consisting of a nitrile group-containing acrylic monomer and an amide group-containing acrylic monomer, the monomer B being at least one selected from the group consisting of a carboxyl group-containing acrylic monomer and an ester group-containing acrylic monomer, a total amount of the monomer A and the monomer B accounting for 70% by weight or more of the monomer mixture, and a weight ratio of the monomer A and the monomer B being 5:5 to 9:1.

First claim

The invention claimed is:

1. A thermally expandable microcapsule,
which comprises a shell containing a copolymer, and a volatile liquid as a core agent included in the shell,
the copolymer being obtainable by polymerization of a monomer mixture containing a monomer A and a monomer B,
the monomer A being at least one selected from the group consisting of a nitrile group-containing acrylic monomer and an amide group-containing acrylic monomer,
the monomer B being t-butyl acrylate and acrylic acid,
a total amount of the monomer A and the monomer B accounting for 70% by weight or more of the monomer mixture, and
a weight ratio of the monomer A and the monomer B being 5:5 to 9:1,
the monomer B being 10% to 30% by weight of t-butyl acrylate and 10% to 30% by weight of acrylic acid, wherein the weigh percentages of t-butyl acrylate and acrylic acid are relative to the total weight of the monomer A and the monomer B.

2. The thermally expandable microcapsule according to claim 1 ,
wherein the nitrile group-containing acrylic monomer is acrylonitrile and the amide group-containing acrylic monomer is at least one selected from the group consisting of acrylamide, an N-substituted acrylamide, and an N,N-substituted acrylamide.

3. The thermally expandable microcapsule according to claim 2 ,
wherein the N-substituted acrylamide is at least one selected from the group consisting of N-isopropylacrylamide, N-methylolacrylamide, N-methoxymethyl acrylamide, N-ethoxymethyl acrylamide, N-propoxymethyl acrylamide, N-isopropoxymethyl acrylamide, N-butoxymethyl acrylamide, N-isobutoxymethyl acrylamide, diacetone acrylamide, and N,N-dimethylaminopropyl acrylamide, and the N,N-substituted acrylamide is at least one selected from the group consisting of N,N-dimethylacrylamide, N,N-diethylacrylamide, and acryloyl morpholine.

4. The thermally expandable microcapsule according to claim 1 ,
wherein the monomer A is acrylonitrile or acrylamide.

5. A method for producing the thermally expandable microcapsule according to claim 1 , the method comprising the step of
polymerizing a monomer mixture containing a monomer A and a monomer B, the monomer A being at least one selected from the group consisting of a nitrile group-containing acrylic monomer and an amide group-containing acrylic monomer, and the monomer B being t-butyl acrylate and acrylic acid.

6. A foamable masterbatch,
which comprises the thermally expandable microcapsule according to claim 1 , and a thermoplastic resin.

7. A foam molded article,
which is obtainable by foam molding of a resin composition containing a thermoplastic resin and one of the thermally expandable microcapsule according to claim 1 .

8. A foam molded article,
which is obtainable by foam molding of a resin composition containing a thermoplastic resin and a foamable masterbatch according to claim 6 .

Assignees

• Morita Hiroyuki
• Yamauchi Hiroshi
• Natsui Hiroshi
• Sekisui Chemical Co Ltd

Inventors

• Morita Hiroyuki
• Yamauchi Hiroshi
• Natsui Hiroshi

Classifications

• C08F220/44

  Acrylonitrile · CPC title

• B01J13/14 Primary

  Polymerisation; cross-linking · CPC title

• C08F220/56

  Acrylamide; Methacrylamide · CPC title