| 摘要 |
PURPOSE:To prevent separation of low-molecular components and additives in resin, by providing heat-insulating material, such as heat-insulating fixed ring, between inside mandrel and die-head, and thereby reducing the portion of exposure of the mandrel. CONSTITUTION:Heat-insulating material, such as heat-insulating fixed ring 10, is provided between inside mandrel 3 and core 9 inside die-head 2, and thereby the exposed part 11 of mandrel 3 is reduced. As the above-mentioned heat-insulating fixed ring 10, it is suitable to use a material excellent in heat resistance and processing, such as tetrafluoroethylene. It is desirable to fit it so as to cover cooling pipe 6 and not to make it contact with the melted resin. |
