| 摘要 |
PURPOSE:To enable to obtain a heat-shrinkable covering material having excellent characteristics which is favorable in heat fusion properties also between laminated sheets at the time of heat treatment and does not generate partial peeling-off or stress cracking on a laminated part, by making use of a silane graft polyolefin sheet as a base film. CONSTITUTION:After a silane graft polyolefin sheet in which a silanole condensation catalyst has been made to exist by an arbitrary device has been wound round a desired core tube and laminated by a desired thickness, the mutual wound sheets are thermally fused through heating, crosslinking is made to generate between polymers, then the diameter of the crosslinked laminated tube 3 is built up continuously up to the desired one by a desired device and cooling and fixing of the tube 3 are performed by leaving the diameter as it is. Matters that heating is started at the temperature lower than the softening temperature of the polyolefin polymer used as heat treatment at the time when the mutual wound sheets are made to fuse and crosslink thermally and the heating temperature is made more than 160 deg.C finally and that the diameter of the crosslinked laminated tube molded over the core tube is built up continuously by making use of an expander of the diameter having a mechanical diameter build-up function are both favorable. |
