Patent ID: 6720067
Filing Date: 2004-04-13
Classification: B32B,C08J,C08K,C08L,Y10T

Abstract:
A porous film comprising a resin composition comprising:(a) a polypropylene base resin blend comprising 100 parts by weight of an ethylene-propylene block copolymer having a maximum peak melting temperature (Tm) of 140Â° C.&lE;Tm&lE;165Â° C. which is given by differential scanning calorimetry (DSC), 3 to 40 parts by weight of low density polyethylene and 3 to 40 parts by weight of ethylene-vinyl acetate copolymer, (b) calcium carbonate, (c) titanium dioxide coated on a surface thereof with silica and/or alumina, (d) a hindered amine light stabilizer having a molecular weight of 1500 to 4500, (e) an ethyl ester phosphorous acid or biphenylene phosphonite antioxidant, and (f) a hindered phenol antioxidant, wherein the above resin composition comprises 100 to 200 parts by weight of (b), 0.5 to 20 parts by weight of (c), 0.2 to 10 parts by weight of (d), 0.03 to 3 parts by weight of (e) and 0.05 to 3 parts by weight of (f) each per 100 parts by weight (a).