| 摘要 |
<p>PURPOSE:To obtain an interlaminar hollow film excellent in light transmittance and heat retaining by equilibrating the pressure of gas supplied in a circular slit, the pressure of gas supplied into the inner side of an interlaminar cylindrical film and the pressure of the cooling water. CONSTITUTION:An inner and an outer circular cooling water tank 2, 3 are provided and the resin which is expanded and extruded cylindrically between the double layers is cooled therewith and, at the same time, the water depth contacting with inner and outer layers of the double cylindrical hollow film are equalized by adjusting the heights on positions of water depth adjusting rings 21 of said inner annular cooling water vessel and external annular cooling water vessel, and of the hollow cylindrical nuts 31; at the same time, the air pressure given under pressure from an air vent 11 formed between both circular slits 8, 9 of the die is balanced with said water pressure in order not to cause bending inward of the inner and outer layers of the film or buckling of the feet between both films. The pressure is balanced also with the gaseous pressure in the cylindrical film to be expanded.</p> |
