This disclosure is to provide a rubber composition excellent in low loss property, breaking resistance and wear resistance. In order to achieve the aforementioned purpose, this disclosure is a rubber composition containing a rubber component having a diene-based polymer and a silica, wherein: the diene-based polymer has 3 or more modified functional groups capable of interacting with the silica merely within a range of of an entire chain length from a terminal, and has at least one monomer structural unit of a diene-based polymer among the modified functional groups; and a content of the silica is 60 to 250 parts by mass per 100 parts by mass of the rubber component.

Provided are surface-modified elastic bodies (e.g. gasket for syringes) each obtained by a surface modification method for modifying a rubber vulcanizate or a thermoplastic elastomer, the method being capable of providing surfaces with excellent properties such as excellent sliding properties, excellent durability against repeated sliding motion, and excellent performance in preventing adsorption and aggregation of proteins, and allowing the surfaces to maintain the sealing properties, without using expensive self-lubricating plastics. The invention relates to surface-modified elastic bodies (e.g. gasket for syringes) at least partially having a surface modified by a surface modification method including: step 1 of forming polymerization initiation points on a surface of an object to be modified that includes a rubber vulcanizate or thermoplastic elastomer, and step 2 of radically polymerizing a monomer containing a CN bond in a molecule thereof, starting from the polymerization initiation points, to grow polymer chains on the surface of the object.

Provided are surface-modified elastic bodies (e.g. gasket for syringes) each obtained by a surface modification method for modifying a rubber vulcanizate or a thermoplastic elastomer, the method being capable of providing surfaces with excellent properties such as excellent sliding properties, excellent durability against repeated sliding motion, and excellent performance in preventing adsorption and aggregation of proteins, and allowing the surfaces to maintain the sealing properties, without using expensive self-lubricating plastics. The invention relates to surface-modified elastic bodies (e.g. gasket for syringes) at least partially having a surface modified by a surface modification method including: step 1 of forming polymerization initiation points on a surface of an object to be modified that includes a rubber vulcanizate or thermoplastic elastomer, and step 2 of radically polymerizing a monomer containing a CN bond in a molecule thereof, starting from the polymerization initiation points, to grow polymer chains on the surface of the object.

Provided are surface-modified elastic bodies (e.g. gasket for syringes) each obtained by a surface modification method for modifying a rubber vulcanizate or a thermoplastic elastomer, the method being capable of providing surfaces with excellent properties such as excellent sliding properties, excellent durability against repeated sliding motion, and excellent performance in preventing adsorption and aggregation of proteins, and allowing the surfaces to maintain the sealing properties, without using expensive self-lubricating plastics. The invention relates to surface-modified elastic bodies (e.g. gasket for syringes) at least partially having a surface modified by a surface modification method including: step 1 of forming polymerization initiation points on a surface of an object to be modified that includes a rubber vulcanizate or thermoplastic elastomer, and step 2 of radically polymerizing a monomer containing a CN bond in a molecule thereof, starting from the polymerization initiation points, to grow polymer chains on the surface of the object.

A thermoplastic resin composition of the present invention contains a graft copolymer (B) obtained by polymerizing a vinyl-based monomer component (m1) in the presence of a composite rubber polymer (A) formed from a polyorganosiloxane (Aa) and a poly(meth)acrylate ester (Ab), and a (meth)acrylate ester resin (C) obtained by polymerizing a vinyl-based monomer component (m2), wherein the amount of the polyorganosiloxane (Aa) relative to the total mass (100% by mass) of the composite rubber polymer (A) is from 1 to 20% by mass, the volume average particle size of the composite rubber polymer (A) is from 0.05 to 0.15 m, and relative to the total mass (100% by mass) of the vinyl-based monomer component (m2), the amount of the maleimide-based compound is from 1 to 30% by mass, and the amount of the aromatic vinyl compound is from 5.5 to 15% by mass.

A thermoplastic resin composition of the present invention contains a graft copolymer (B) obtained by polymerizing a vinyl-based monomer component (m1) in the presence of a composite rubber polymer (A) formed from a polyorganosiloxane (Aa) and a poly(meth)acrylate ester (Ab), and a (meth)acrylate ester resin (C) obtained by polymerizing a vinyl-based monomer component (m2), wherein the amount of the polyorganosiloxane (Aa) relative to the total mass (100% by mass) of the composite rubber polymer (A) is from 1 to 20% by mass, the volume average particle size of the composite rubber polymer (A) is from 0.05 to 0.15 m, and relative to the total mass (100% by mass) of the vinyl-based monomer component (m2), the amount of the maleimide-based compound is from 1 to 30% by mass, and the amount of the aromatic vinyl compound is from 5.5 to 15% by mass.

This invention relates to a process for the preparation of a silane-functionalized resin composition comprising the steps of mixing a polymer backbone, a silane, and a free radical initiator; and producing a silane-functionalized resin composition. The polymer backbone is selected from at least one of dicyclopentadiene (DCPD)-based polymers, cyclopentadiene (CPD)-based polymers, DCPD-styrene copolymers, C.sub.5 homopolymers and copolymer resins, C.sub.5-styrene copolymer resins, terpene homopolymer or copolymer resins, pinene homopolymer or copolymer resins, C.sub.9 homopolymers and copolymer resins, C.sub.5/C.sub.9 copolymer resins, alpha-methylstyrene homopolymer or copolymer resins, and combinations thereof.

This invention relates to a process for the preparation of a silane-functionalized resin composition comprising the steps of mixing a polymer backbone, a silane, and a free radical initiator; and producing a silane-functionalized resin composition. The polymer backbone is selected from at least one of dicyclopentadiene (DCPD)-based polymers, cyclopentadiene (CPD)-based polymers, DCPD-styrene copolymers, C.sub.5 homopolymers and copolymer resins, C.sub.5-styrene copolymer resins, terpene homopolymer or copolymer resins, pinene homopolymer or copolymer resins, C.sub.9 homopolymers and copolymer resins, C.sub.5/C.sub.9 copolymer resins, alpha-methylstyrene homopolymer or copolymer resins, and combinations thereof.