Leak stop plug against needle piercing and method of manufacturing the leak stop plug

摘要

A pierceable stopper enhanced in elasticity so that the liquid in a container will not leak even after a hollow needle inserted into the container through the pierceable stopper has been removed therefrom and a method of producing the pierceable stopper are provided. A pierceable part (11) through which a hollow needle is inserted into a container (2) is molded from a thermoplastic synthetic resin elastic material. The pierceable part is heat-treated with heated air at a temperature of from 80 to 120° C. to remove the internal stress. The heat-treated pierceable part (11) is inserted into an injection mold (20, 21). A molten thermoplastic synthetic resin is injected into a cavity (26) corresponding to a stopper body (10), which is defined by the injection mold (20, 21) and the pierceable part (11), to form a pierceable stopper (5).