Surface modification method, surface-modified elastic body, gasket for injector, injector, and tire

A surface-modified elastic body implemented by performing property modification on a surface of a thermoplastic elastomer or vulcanized rubber, which has a polymer brush formed by polymerizing a monomer from a polymerization initiation site acting as a point of initiation for polymerization by the atom transfer radical polymerization (ATRP) method, said polymerization initiation site being formed by causing a secondary or tertiary organic halide to bind to a hydroxyl group formed on said surface in a manner such that a water contact angle of said surface becomes 8 to 50 degrees smaller than a value of a water contact angle in an unmodified condition.

An injector in which a plunger integrally formed with a gasket made of a thermoplastic elastomer or a vulcanized rubber slides over an inner surface of a syringe, said gasket having a sliding surface with a polymer brush formed by following a step of forming a hydroxyl group in a manner such that a water contact angle of said sliding surface becomes 8 to 50 degrees smaller than a value of a water contact angle in an unmodified condition and a step of polymerizing a monomer from a polymerization initiation site acting as a point of initiation for polymerization by atom transfer radical polymerization (ATRP) method, AGET ATRP method, or ARGET ATRP method, said polymerization initiation site being formed by causing a secondary or tertiary organic halide to bind to said hydroxyl group.

An injector in which a plunger slides over an inner surface of a syringe, said syringe being made of a thermoplastic elastomer or a vulcanized rubber, said inner surface of said syringe having a polymer brush formed by following a step of forming a hydroxyl group in a manner such that a water contact angle of said sliding surface becomes 8 to 50 degrees smaller than a value of a water contact angle in an unmodified condition and a step of polymerizing a monomer from a polymerization initiation site acting as a point of initiation for polymerization by atom transfer radical polymerization (ATRP) method, AGET ATRP method, or ARGET ATRP method, said polymerization initiation site being formed by causing a secondary or tertiary organic halide to bind to said hydroxyl group.

A gasket for injector integrally formed with a plunger of an injector that slides over an inner surface of a syringe, which is made of a thermoplastic elastomer or a vulcanized rubber, said gasket having a surface which slides over the inner surface of said syringe, said sliding surface having a polymer brush formed by following a step of forming a hydroxyl group in a manner such that a water contact angle of said surface becomes 8 to 50 degrees smaller than a value of a water contact angle in an unmodified condition and a step of polymerizing a monomer from a polymerization initiation site acting as a point of initiation for polymerization by atom transfer radical polymerization (ATRP) method, AGET ATRP method, or ARGET ATRP method, said polymerization initiation site being formed by causing a secondary or tertiary organic halide to bind to said hydroxyl group.

A tire having a tread formed with a groove, which is made of a thermoplastic elastomer or a vulcanized rubber, said groove having an inner surface with a polymer brush formed by following a step of forming a hydroxyl group in a manner such that a water contact angle of the inner surface becomes 8 to 50 degrees smaller than a value of a water contact angle in an unmodified condition and a step of polymerizing a monomer from a polymerization initiation site acting as a point of initiation for polymerization by atom transfer radical polymerization (ATRP) method, AGET ATRP method, or ARGET ATRP method, said polymerization initiation site being formed by causing a secondary or tertiary organic halide to bind to said hydroxyl group.