| 摘要 |
PURPOSE:To obtain a film, the stretching of which is easy and which is excellent in low temperature heat shrinkability, by making a structure wherein both outer layers consist of straight-chain low-density polyethylene having a density of 0.915-0.935g/cm<3> and a melting point of 120-128 deg.C and an intermediate layer consists of straight-chain low-density polyethylene having a density of 0.890-0.910g/cm<3> and a Vicat softening point of 75 deg.C or lower and the thickness of said intermediate layer is set to be 30-80% of the total thickness. CONSTITUTION:A laminated unstretched stock sheet comprising both outer layers, each of which consists of straight-chain low-density polyethylene having a density of 0.915-0.935g/cm<3> and a melting point of 120-128 deg.C and an intermediate layer, which consists of straight-chain low-density polyethylene having a density of 0.890-0.910g/cm<3> and a Vicat softening point of 75 deg.C or lower is obtained by three- layer coextrusion. The laminated unstretched stock sheet is stretched longitudinally and laterally by the conventional method such as blown-film extrusion. After that, the laminated biaxially stretched film is thermally set under relaxation in order to obtain a heat-shrinkable film. Further, at that time, the thickness of said intermediate layer is set to be 30-80% of the total thickness. Thus, the film, the stretching of which is easy and which is excellent in low temperature heat shrinkability, is obtained. |
