| 摘要 |
Provided are a polyester heat shrinkable tube whose length and/or width are simultaneously shrunk when cured after heating and which is environmental friendly and is reduced in percent defective, and an apparatus for preparing the tube. The polyester heat shrinkable tube comprises a polyester resin; 0.1-10 wt% of a wax; and 0.1-20 wt% of a silica powder based on the amount of the polyester resin. Preferably the wax is ethylene bisstearamide. The apparatus comprises an extruder(10) where a tube is extruded; an expansion molding pipe(30) which is installed on the transport path of the molded tube and whose inner face is pressed with a tube by the compressed air supplied into the inside to be expanded and be transported; and first pressing rollers(20, 22) and second pressing rollers(40, 42) which are provided in front and back sides of the expansion molding pipe to the tube to allow the compressed air supplied in the tube to be maintained in the inside of the tube passing through the expansion molding pipe without discharging. A slip layer(50) comprising a fluorine resin or silicon is provided in the inner surface of the expansion molding pipe to reduce the friction force between the tube and the expansion molding pipe during the transport of the tube.
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