| 摘要 |
PURPOSE: To obtain a film having longitudinally and laterally stable strength by controlling the temp. of a molten tubular film reduced in pressure by a mandrel having a tubular film introducing and holding part, a stretching preparatory expanding part and a pressure reducing suction braking part and a stretching preheating zone and arranging the same by an expanding and annealing cylinder in a biaxial stretching zone. CONSTITUTION: A mandrel is provided so that a tubular film is held to a non- oriented state in a tubular film introducing and holding part 40 and the close adhesiveness to the mandrel is enhanced and film shrinkability is applied. In the tubular film vacuum sucking control part 1 of a stretching preparatory expansion part 10, the temp. of the tubular film is controlled to a thermoplastic synthetic resin stretching fitting temp. range from the inner surface thereof by the hot and cold temp. control medium liquid circulating in the mandrel. The tubular film taken over in the biaxial stretching zone is expanded so that the diameter thereof becomes larger than the inner diameter of the inlet of the annealing cylinder from a biaxial stretching pressure atmosphere emitting port 18 to be forcibly stretched. The wrinkles and slackening of film appearance other than crystalliztion are corrected in an annealing zone. |
