Abstract: Heat-expandable microspheres having a thermoplastic resin shell and a thermally-vaporizable blowing agent encapsulated therein. The thermoplastic resin is a copolymer produced from a polymerizable component containing 15 to 90 wt % of acrylonitrile, 3 to 50 wt % of an acrylate ester monomer (A) represented by formula (1) shown below, and 3 to 70 wt % of a methacrylate ester monomer (B) represented by formula (2) shown below. The weight ratio of the acrylate ester monomer (A) represented by formula (1) to the methacrylate ester monomer (B) represented by formula (2) in the polymerizable component (A:B) ranges from 10:90 to 90:10: H2C?CH—COOR1??(1) H2C?C(CH3)—COOR2??(2). Also disclosed are hollow particles manufactured by expanding the heat-expandable microspheres; a composition containing a base compound and the heat-expandable microspheres or the hollow particles; and a formed product manufactured by molding or applying the composition.

Abstract: Heat-expandable microspheres having a thermoplastic resin shell and a thermally-vaporizable blowing agent encapsulated therein. The thermoplastic resin is a copolymer produced from a polymerizable component containing 15 to 90 wt % of acrylonitrile, 3 to 50 wt % of an acrylate ester monomer (A) represented by formula (1) shown below, and 3 to 70 wt % of a methacrylate ester monomer (B) represented by formula (2) shown below. The weight ratio of the acrylate ester monomer (A) represented by formula (1) to the methacrylate ester monomer (B) represented by formula (2) in the polymerizable component (A:B) ranges from 10:90 to 90:10: H2C?CH—COOR1??(1) H2C?C(CH3)—COOR2??(2). Also disclosed are hollow particles manufactured by expanding the heat-expandable microspheres; a composition containing a base compound and the heat-expandable microspheres or the hollow particles; and a formed product manufactured by molding or applying the composition.

Abstract: A process for producing heat-expandable microspheres including a thermoplastic resin shell and a blowing agent encapsulated therein. The process includes the steps of dispersing a polymerizable component and the blowing agent in an aqueous dispersion medium having a pH of 7 or less and containing a fine-particle metal compound having a mean particle size ranging from 1.0 to 10 nm, and polymerizing the polymerizable component. The amount of the fine-particle metal compound ranges from 0.15 to 20 parts by weight to 100 parts by weight of the total amount of the polymerizable component and the blowing agent. Also disclosed are heat-expandable microspheres produced by dispersing a polymerizable component and a blowing agent in an aqueous dispersion medium containing colloidal silica and polymerizing the polymerizable component.

Abstract: A process for producing heat-expandable microspheres including a thermoplastic resin shell and a blowing agent encapsulated therein. The process includes the steps of dispersing a polymerizable component and the blowing agent in an aqueous dispersion medium having a pH of 7 or less and containing a fine-particle metal compound having a mean particle size ranging from 1.0 to 10 nm, and polymerizing the polymerizable component. The amount of the fine-particle metal compound ranges from 0.15 to 20 parts by weight to 100 parts by weight of the total amount of the polymerizable component and the blowing agent. Also disclosed are heat-expandable microspheres produced by dispersing a polymerizable component and a blowing agent in an aqueous dispersion medium containing colloidal silica and polymerizing the polymerizable component.