| 摘要 |
PURPOSE:To obtain a film having oxygen barrier properties and high dimensional stability under high temperatures by a method wherein saponified ethylene-vinyl acetate copolymers each having an ethylene content of 20-50mol% and a degree of saponification of vinyl acetate component of at least 90mol% are coextruded into a multilayer film, which is then stretched. CONSTITUTION:Saponified ethylene-vinyl acetate copolymers each having an ethylene content of 20-50mol% and a saponification degree of vinyl acetate component of at least 90% are co-extruded into a multilayer film at 170-270 deg.C by multilayer inflation molding method, T-die extrusion method, multilayer blow molding method or the like. The thickness of the film can be in the range from that of a sheet to those of pipes, containers, etc. The multilayer film thus co-extruded is stretched after an appropriate moisture absorbing treatment or the like. The stretching is conducted either uniaxially or biaxially. |
