| 摘要 |
PURPOSE:To obtain a highly oriented film by cold drawing having improved low- temperature shrink characteristics and a wide range of packaging adaptobility temperatures, by extruding a composition consisting of a polyolefin and a thermoplastic elastomer made of an alpha-elefin copolymer from a ring dir, followed by orientation. CONSTITUTION:A composition consisting of A) 95-10 wt.% of a polyolefin and B) 5-90 wt.% of a thermoplastic elastomer made of an alpha-olefin copolymer is mixed to give a molten blend. The blend is extruded from a ring-die, quenched by a liquid refrigerant, and set to make a raw tubular film, which is irradiated with high energy rays so that it has boiling xylene insoluble gel content not more than 60 wt.% and a melt index not more than 1.0. The film is then heated up to not more than 110 deg.C and air is blown into the film between two pairs of nip rolls at 20-100 deg.C so that the film is orientated in a cold state at an area draw ratio of 5-30:1 and at a cross direction draw ratio of 2:7:1. |
