| 摘要 |
PURPOSE:To make frictional resistance low at the time of passing through a die, which becomes the cause of longitudinal elongation of a resin tube, by a method wherein a cooling liquid is fed to the circumference of the tube and expansion molding is performed continuously with suction force through negative pressure while cooling. CONSTITUTION:An end port is sealed, compressed air is pressed in through the other end, which is heated by introducing the same into a heating tank and introduced into a precooling part 7 and die 8, in a resin tube A. The title device is constituted so that a cooling liquid 10 is spouted out through the precooling part 7 and the inside of a tank 11 is sucked with a vacuum pump. The cooling liquid 10 is fed continuously within an annular tank by the precooling part 7 and sent out to the outer circumference of the resin tube A through a spouting hole 7b. Since the die 8 is constituted so that the same is provided with a plurality of through holes 8b and a pipe diameter is expanded while lubricating a space between the die 8 and the resin tube A with the cooling liquid released within a depressurizing tank 11, very small and high- quality heat-shrinkable tube can be manufactured at a high rate. |
