| 摘要 |
An apparatus for biaxially stretching a tubular film, by the use of a heated pressurized fluid supplied in the inside of the expanding tubular film and allowing to leak a part of the fluid through a thin layer clearance between the expanded tubular film and an inserted mandrel at the outside thereof and the difference of speeds between the feed side and takeup side, which is characterized by cylindrical nets of variable diameter, whose upper ends are fixed and on which a positive tension is applied vertically downwards, and which are provided at a leakage section of a heating pressurized fluid filling a thin layer clearance between the outer periphery of an umbrellalike insulating membrane and an expanded tubular film and at the discharge section of a cooling liquid along the outer periphery of an inserted bag mandrel and the expanded tubular film, respectively, to give a uniform and sufficient discharging resistance to the fluid at the entire outer periphery of the bag mandrel and thereby to reduce the leakage of the heating pressurized fluid, and to attain the facilitation of the pressure maintenance in the stretching section above the insulating membrane as well as the uniform discharge of the cooling liquid around the entire outer periphery of the bag mandrel.
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