GASKET

摘要

PROBLEM TO BE SOLVED: To provide a gasket excellent in slidability even if a lubricant is not imparted and capable of holding liquidtightness as well as to provide a gasket for preventing separation of a resin film from a gasket body and a molding defect such as a pinhole. SOLUTION: A syringe 1 indicated in a drawing 1 has an outer cylinder 2, the gasket 3 slidable in the outer cylinder 2 and a plunger 4 for movably operating the gasket 3. This gasket 3 is formed by covering at least the outer periphery of the gasket body 5 with the resin film 6 composed of a material having a friction coefficient lower than a gasket body material, and satisfies the relationship of 1.5 Ra1<=Ra2 when surface roughness of an outside surface (an outer cylinder 2 side surface) 61 of the resin film 6 is Ra1 and surface roughness of an inside surface (a gasket body 5 side surface) 62 of the resin film 6 is Ra2.