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

摘要

Provided are: surface modification method for imparting slidability to surface of elastic body such as vulcanized rubber or thermoplastic elastomer without using expensive self-lubricating resin; surface-modified elastic body with polymer brush formed on its surface; and gasket for injector and injector formed of surface-modified elastic body. The surface modification method applies to surface of thermoplastic elastomer or vulcanized rubber. The surface modification method comprises the step of forming hydroxyl group on surface of to-be-modified object such as rubber so that water contact angle of the surface becomes 8 to 50 degrees smaller than original water contact angle in unmodified condition, the step of forming polymerization initiation site by subjecting the hydroxyl group to action of secondary or tertiary organic halide, and the step of growing polymer brush on the surface of to-be-modified object by subjecting monomer to radical polymerization at the polymerization initiation site acting as a point of initiation.

主权项

1. A surface modification method for a thermoplastic elastomer or a vulcanized rubber surface comprising the steps of:
subjecting the thermoplastic elastomer or vulcanized rubber surface to ultraviolet irradiation so as to form hydroxyl groups under a condition of reducing a value of the water contact angle of the surface by 8 to 50 degrees as compared to a value of the water contact angle of the surface before irradiation on a basis of a relationship between an ultraviolet irradiation time and a decreasing degree of a value of the water contact angle after irradiation to the thermoplastic elastomer or vulcanized rubber surface; reacting the formed hydroxyl groups on the surface with a secondary or tertiary organic halide so as to form polymerization initiation sites; and subjecting the surface polymerization initiation sites to radical polymerization conditions along with providing a monomer source so as to grow a polymer brush on the thermoplastic elastomer or vulcanized rubber surface.