| 摘要 |
PURPOSE:To obtain a film which has an improved strength and is excellent in an uneven thickness precision, by a method wherein an acrylonitrile polymer, reinforced with rubber containing 50-90wt% acrylnitril is logitudinally and transversely stretched 1.5-5.0 times at a given temperature. CONSTITUTION:An acrylonitrile polymer, reinforced with rubber, containing 50-90wt% acrylonitrile is fused, and an unstretched tubular film is extruded to be rolled around a winder 1. The stretched tubular film is unwound from the winder 2, and is longitudinally and transversely 1.5-3.0 times through the working of pinch rolls 5, 5', consisting of a metal roll and a rubber roll, at the temperature of the polymer, heated to glass transition point - glass transition point +70 deg.C by means of a heating far infrared heater 6, and through the pressure of air fed inside. This produces a stretched film 3 which is rolled around a winder 4. |
