| 摘要 |
PURPOSE:To obtain a film which is excellent in an oxygen-insulating property and a transparency, by a method wherein a distance from an extruding dice outlet to an inflation completion and a temperature of a film positioned just in front of a nip roll are set at specified values. CONSTITUTION:A copolymer, in which 50-95pts.wt. acrylonitrile and 50-5 pts.wt. acryl acid methyl are graft-polymerized, is fused under the existence of 3-30pts.wt. butadiene-acrylonitrile copolymer containing 40-95wt% butadiene. So fused copolymer is extruded in a tubular shape through a ring dice 2, and is inflated up to a film having a diameter equivalent to its given folding width as it is cooled by means of a cooling air ring 3. The resultant work is nipped with nip rolls 7 to form a film 8. Through the adjustment of an air amount and an air temperature at the air ring 3, a distance from a dice outlet to an inflation completion point 4 is regulated so as to become not less than 300mm., and a temperature of a film positioned just in front of the nip roll is set at Tg-40 deg.C-Tg+20 deg.C (Tg: glass transition point). |
