| 摘要 |
PROBLEM TO BE SOLVED: To make weight lighter by previously forming a release layer consisting of a silicon polymer of a fluorine polymer on the surface of a flexible tube for internal pressure packing used at the time of thermal molding in a metal mold and removing the flexible tube from a frame after the molding. SOLUTION: The surface of the flexible tube 30 is provided with the release layer 31 consisting of the silicon polymer and/or fluorine polymer, by which the drawing of the flexible tube from the inside of the frame after the molding is made possible. A tube of high tensile strength in spite of the relatively thin thickness of, for example, a nylon tube, or the like, used thus far is usable for the flexible tube 30 itself. The flexible tube, therefore, elongates along the inside surface of the mold part 21 of the metal mold M without rupturing in spite of the intricate crass-sectional surface shape of the mold part when the internal pressure of the flexible tube is increased by filling a high-pressure fluid into the flexible tube at the time of the molding. The drawing of the tube from the inside of the frame by the release layer disposed on the surface of the tube after the molding is thus made possible. |
