| 摘要 |
<p>In a process for fabricating a laminated cylindrical film with a plastic resin base, the laminated structure consists of three layers, the inner layer being stretch oriented transversely and the outer layer being stretch oriented longitudinally. The median layer is formed from a film having a lower fusion point than the inner and outer layers, and consolidation is brought about by heating to a temp. slightly below the fusion point of the median layer so that it is bonded to the other two layers. The three layers may be extruded from annular concentric orifices, and orientation in perpendicular directions gives greater strength and enables thinner films to be used for a given weight. The three films are extruded from concentric orifices. The outer layer is then stretched longitudinally between two sets of rolls while the inner film is expanded by a rotating mandrel, the film being then cooled rapidly and flattened. The outer and inner layers may be of a high m.pt. polyolefin while the median film may be of e.g. ethylene/vinyl acetate or ethylene/acrylonitrile copolymers.</p> |
