| 摘要 |
PURPOSE:To obtain a moisture permeable and waterproof film excellent in moisture permeability and stable in waterproofness by a method wherein material, the essential ingredients of which are polyolefin-based resin and additive resin scarcely compatible with the polyolefin- based resin, is melted and kneaded under the specified conditions and, after that, extruded at the specified temperature in the form of film and cooled down and finally said cooled and unstretched film is stretched uniaxially. CONSTITUTION:The essential ingredients of a material are polyolefin-based resin A and thermoplastic resin B scarcely compatible with the polyolefin-based resin. From 100pts.wt. of B, the energy of fluidization and activation which is 20kcal/mol or more with respect to 100pts.wt. of A, the energy of fluidization and activation which is 15kcal/mol or less are melted and kneaded under a condition that the melt viscosity ratio etaB/etaA is 1.1-100 and, after that, extruded in the form of film at a temperature, at which the melt viscosity ratio etaB/etaA is 1.5 or larger. The resultant cooled and unstretched film is stretched at least in one axial direction. The scattering of performance and trouble in a method for blending two kinds of resins, the compatibility between which is small, are prevented from occurring and consequently a moisture permeable and waterproof film excellent in both moisture permeability and waterproofness is efficiently obtained.
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