| 摘要 |
PURPOSE:To provide the titled film which is uniform without having such defects as ribs and creases in the circumferential direction thereof, by sealing a gas into a cylindrical film discontinuously. CONSTITUTION:A raw material resin 1 is fed from a hopper 7, is melted by heating, is fed in the direction of arrow 8, is extruded from a circular die part 2 and the cylindrical film is stretched by feeding compressed air from a feeding part 3 into the inside of the cylindrical film. Then, the air in the cylindrical film is sealed discontinuously by moving heating rollers 6 in the direction of arrows 11, thereby obtaining the objective cylindrical thermo-shrinkable film 9. |
