| 摘要 |
PURPOSE:To produce a wide thermoplastic resin flat film with little trimming loss or unevenness by extruding a thermoplastic resin melted by a ring-shaped die in a cylindrical form, splitting a cylindrical bubble in its flowing direction with a cutting knife after swelling said resin with air from inside, cooling, solidifying and taking the same as a piece of flat-shaped film. CONSTITUTION:Cylindrical molten resin extruded from a ring-shaped die 2 is cooled by air for cooling from an air tank 3 and at the same time swollen by the air inside and forms a cylindrical bubble. Part of the air inside is leaked out of a space between the bubble and a barrier material 6, and the air of same volume as said leakage is replenished from an inside air introducing line 4 in the lower section of the ring-shaped die 2 to maintain the blow-up of the bubble constant. The bubble blown up is split into a piece of a wide flat film with a cutting knife 7 fixed in the direction of flowing and taken by a take-up roll 8. |
