| 摘要 |
<p>PURPOSE:To highly densify the projections developed by particles contained and to uniformize the height of the projections and, at the same time, uniformize the widthwise lamination thickness of the film concerned by a method wherein the thickness of thermoplastic resin A in unstretched sheet-like material is made to be specified times as large as the mean particle diameter of the particle containing therein and the areal biaxial draw ratio of the unstretched sheet-like material is made to be specified-fold. CONSTITUTION:By filtering melt of thermoplastic resin A before lamination through a filter, the 95% filtering accuracy of which is 30mum or less, the thickness of thermoplastic resin layer in unstretched sheet-like material is made to be 5-80 times as large as the mean particle diameter of the particle containing in the thermoplastic resin A. The unstretched sheet-like material is stretched through the stage of biaxial stretching so as to realize the areal draw ratio of (8-50)-folds. Thus, the surface projections of the film of the thermoplastic resin A layer are produced by the particles, which are equal to or slightly larger than those of the laminated film layer of the thermoplastic resin A, resulting in surely realize the high densification of the projections formed and the uniformization of their heights. At the same time, due to high draw ratio, superior physical properties as biaxially stretched thermoplastic resin film are ensured.</p> |
