| 摘要 |
PURPOSE:To provide both of good heat resistance and heat weldability by regulating the acceleration voltage of the electron beam allowed to irradiate a tubular or bag-like instrument composed of a vinyl/vinyl ester copolymer and reducing the crosslinking degree of said copolymer in the thickness direction from the outside of the instrument to the inside thereof. CONSTITUTION:A copolymer formed by polymerizing a vinyl monomer and a vinyl ester monomer is molded into a tubular or bag like shape. The thickness of this molded article is generally set to 0.1-1.0mm. Electron beam is allowed to irradiate the molded article so that the crosslinking degree of the copolymer becomes low in the thickness direction from one side of the molded article to the other side thereof when the molded article has a sheet-like shape. The crosslinking degree different in the thickness direction is obtained by regulating the acceleration voltage of electron beam to be allowed to irradiate. By this crosslinking structure, the heat resistance of an instrument is improved as a whole and the heat weldability of the inside of the instrument is not lowered. |
