Stopper assembly for medical liquid container and method and apparatus for manufacturing the same

A stopper assembly for a medical liquid container, comprising an inner cylindrical stopper member formed of a plastic material, a rubber plug member hermetically contained in a chamber formed within said inner stopper member by first and second partition walls, said second partition wall being thinner than said first partition wall and sealing said rubber plug member from contact with a liquid in the container, said first partition wall being provided with an annular score, said second partition wall being formed at a position spaced from a base portion of the stopper assembly a distance sufficient enough to reduce heat transfer thereto from the base portion upon heat sealing thereof, an outer cylindrical stopper member formed of a plastic material and hermetically welded around and surrounding said inner stopper member, a pulling member formed in said first partition wall at a region enclosed by said annular score and being disposed and enclosed in the inner cylindrical stopper member;

• said outer stopper member having an inner flange formed at the top end thereof and an outer flange formed at the bottom end thereof, said inner flange covering the top end of said inner stopper member, said outer flange being welded to an outer flange formed at the bottom end of said inner stopper member, both of said outer flanges being hermetically welded to a top end of the mouth of said container.