| 摘要 |
PURPOSE:To stabilize molding by lowering the frost line of a molten bubble by a reduced amt. of cooling air and reducing the fine movement of the molten bubble to enhance the thickness accuracy of a film by employing a downward air cooling inflation film molding method. CONSTITUTION:A thermoplastic resin, for example, polyethylene, an ethylene/ propylene copolymer, polystyrene, polyvinyl chloride, polyamide or polyether is extruded from the tubular die of an extruder in a molten state and gas of which the density is lower than that of air, for example, hydrogen, helium, nitrogen or methane is blown into the extruded molten bubble. Herein, the density of gas is pref. 0.0013g/cm<3> or less in a standard state (0 deg.C, 1atm). A downward air cooling inflation film molding method wherein the molten bubble extruded from the die is inflated by the inner pressure of the gas blown in the bubble and cooled and solidified by an air cooling ring to be continuously taken up is employed. |
