| 摘要 |
PURPOSE:To reduce a natural shrinkage factor, and to obtain a film excellent even in printing properties by quenching the film so as to reach to a specific temperature or lower, annealing it within a specific temperature range and quenching it. CONSTITUTION:When manufacturing a polypropylene group heat-shrinkable film, a tubular film discharged from a dice 1 is cooled and solidified by a cooling ring 2, and heated by a heater 8, and a gas is encapsulated after the heating. The film is quenched at 30 deg.C or lower by cooling rolls 9, annealed at 50-75 deg.C in an annealing tank 10, and quenched at 30 deg.C or lower by cooling rolls 11, a gas is encapsulated among nip rolls 6, 7, and the film is wound by a rotating winder through a guide roll 12. Accordingly, a natural shrinkage factor is reduced, and the heat-shrinkable film, which is not tightened through winding and is excellent in smoothness while it can also be printed, can be obtained. |
