Abstract: Heat-expandable microspheres include a shell of thermoplastic resin and core material encapsulated in the shell. The core material include a blowing agent having a boiling point not higher than the softening point of the thermoplastic resin and a gas migration inhibitor having a boiling point higher than the softening point of the thermoplastic resin. The ratio of the gas migration inhibitor to the core material is at least 1 weight percent and below 30 weight percent. The average particle size of the heat-expandable microspheres ranges from 1 to 100 micrometers.

Abstract: A rubber composition for a tire containing (i) 100 parts by weight of a diene-based rubber and (ii) 0.5 to 25 parts by weight of a heat-expandable microcapsule including a shell, and a substance capable of vaporizing or expanding under heating to thereby generate a gas and a nonpolar oil, both encapsulated in the shell, wherein the shell is made of a thermoplastic resin obtained by polymerization of a nitrile-based monomer (I), a monomer (II) having an unsaturated double bond and a carboxyl group in the molecule thereof, an optional monomer (III) having two or more polymerizable double bonds, and an optional copolymerizable monomer (IV) for adjusting the expansion properties.

Abstract: Heat-expandable microspheres include a shell of thermoplastic resin and core material encapsulated in the shell. The core material include a blowing agent having a boiling point not higher than the softening point of the thermoplastic resin and a gas migration inhibitor having a boiling point higher than the softening point of the thermoplastic resin. The ratio of the gas migration inhibitor to the core material is at least 1 weight percent and below 30 weight percent. The average particle size of the heat-expandable microspheres ranges from 1 to 100 micrometers.

Abstract: A rubber composition for a tire containing (i) 100 parts by weight of a diene-based rubber and (ii) 0.5 to 25 parts by weight of a heat-expandable microcapsule including a shell, and a substance capable of vaporizing or expanding under heating to thereby generate a gas and a nonpolar oil, both encapsulated in the shell, wherein the shell is made of a thermoplastic resin obtained by polymerization of a nitrile-based monomer (I), a monomer (II) having an unsaturated double bond and a carboxyl group in the molecule thereof, an optional monomer (III) having two or more polymerizable double bonds, and an optional copolymerizable monomer (IV) for adjusting the expansion properties.

Abstract: A rubber composition containing 100 parts by weight of a diene-based rubber and 0.5 to 25 parts by weight of a heat expandable microcapsule composed of a thermoplastic resin particle having a substance enclosed therein, capable of vaporizing or expanding due to heat to thereby generate a gas, wherein a shell of the heat expandable microcapsule comprises a thermoplastic resin obtained by polymerization from, as a main component of a monomer, a nitrile-based monomer (I), a monomer (II) having an unsaturated double bond and carboxyl group in the molecule thereof, a monomer (III) having two or more polymerizable double bonds and, optionally, a copolymerizable monomer (IV) for adjusting the expansion characteristics, and a pneumatic tire using the same, whereby the tire weight is decreased and the ice traction thereof is improved.

Abstract: Thermo-expansive microcapsules comprising a shell of a polymer produced by polymerizing a mixture of monomers, which comprises (I) a nitrile monomer, (II) a monomer having an unsaturated double bond and carboxyl groups in a molecule, (III) a monomer having two or more of polymerizable double bonds in a molecule, and optionally, (IV) a monomer different from and copolymerizable with the monomers (I), (II) and (III) and a blowing agent encapsulated in the shell. The volume retention of the expanded microcapsules of the thermo-expansive microcapsules is 50% or more after loaded with 15 MPa.

Abstract: Thermo-expansive microcapsules comprising a shell of a polymer produced by polymerizing a mixture of monomers, which comprises (I) a nitrile monomer, (II) a monomer having an unsaturated double bond and carboxyl groups in a molecule, (III) a monomer having two or more of polymerizable double bonds in a molecule, and optionally, (IV) a monomer different from and copolymerizable with the monomers (I), (II) and (III) and a blowing agent encapsulated in the shell. The volume retention of the expanded microcapsules of the thermo-expansive microcapsules is 50% or more after loaded with 15 MPa.