To provide a porous polypropylene film which has excellent tear strength and a thermal shrinkage factor of ≤5% and can give laminated sheets having excellent moisture permeability, weather resistance and heat resistance, to provide a method for producing the porous film, and to provide a laminated sheet obtained by laminating the porous film to a polyolefin nonwoven fabric.
This porous film comprises 100 pts.wt. of a resin composition, 100 to 200 pts.wt. of calcium carbonate, 0.5 to 20 pts.wt. of titanium oxide whose surface is coated with silica and/or alumina, 0.2 to 10 pts.wt. of a hindered amine photostabilizer having a mol.wt. of 1,500 to 4,500, 0.03 to 3 pts.wt. of biphenylene phosphite antioxidant, and 0.05 to 3 pts.wt. of a hindered phenolic antioxidant. The porous film is molded in a specific thermal treatment condition. The resin composition comprises 100 pts.wt. of ethylene-propylene block copolymer, 3 to 40 pts.wt. of low density polyethylene and 3 to 40 pts.wt. of ethylene-vinyl acetate copolymer.
OZAKI DAISUKE
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