| 摘要 |
<p>[Problem] To provide a piston member that is for a syringe and that can sufficiently satisfy slidability and the sealing properties of being liquid non leaking water vapor impermeable and the like without a limitation in size from a small diameter to a large diameter and moreover being low cost. [Solution] The piston member (10) such as a gasket (10a) and an intermediate piston (10b) is formed by cutting/machining a PTFE block and is used in a sliding state having been pressed into a syringe barrel (1). Of the sliding contact surface (11) of the piston member (10) that is in sliding contact with the inner peripheral surface (2) of the syringe barrel (1) a peripheral direction convex band (13) is formed across at least the entire periphery of the sliding contact surface (11a) abutting a liquid contacting surface (14) that contacts a drug (30). The pitch (P) of the convex band (13) during cutting/machining is no greater than 50 µm and the press in margin (T) with respect to the syringe barrel (1) is 10 150 µm.</p> |
