| 摘要 |
PURPOSE:To manufacture two-layer film excellent in tear-resistance, edge-separability, electrostatic friction factor, etc. by a method wherein resin for composing an internal and an external layer is specified and inflation-molded at a specified temperature. CONSTITUTION:The internal layer part is made from high density polyethylene having melt indexes of about 0.03-0.2 and the external layer part is made from low density polyethylene or ethylene-vinyl acetate copolymer (containing vinyl acetate of about 5-30% by weight). They are introduced into a two-layer circular die, the resin stream only on the external layer is heated in the die up to temperatures of 180-220 deg.C, then the inside and outside resins are combined into a cylindrical body and a two-layer film is formed by inflation molding according to the usual method. |
