MANUFACTURE OF MOLDIFIED FILM

PURPOSE:To obtain a film excellent in transparency and the smoothness of the inner surface while the aging of its surface is prevented at the same time as inflation molding by introducing fluorine gas into the relatively upper part of the hollow space of resin bubble discharged from a die, and introducing a gas containing no fluorine into the lower part thereof. CONSTITUTION:Molten resin is extruded from an annular die 9 by an extruding machine 10, and the obtained tubular film (bubble) 1 is nipped by a nip roll 1, and then the film is wound on a winding machine 12. The hollow space of the bubble is divided into an upper part 2 and a lower part 3 by a hollow space dividing device 4. A gas containing fluorine to be introduced in the upper part 2 of the bubble-hollow space, as a blowing gas, is introduced from a conduit 5 and is discharged from a conduit 6. A gas containing no fluorine to be intro duced in the lower part 3, e.g. nitrogen gas is introduced from a conduit 7 and is discharged from a conduit 8. When the gas is introduced thereinto, the molten resin is expanded to be a bubble 1. After the bubble has attained a constant width and a constant thickness, it is cut by a cutter, and is wound on the winding machine 12.