Patent ID: 6121363
Filing Date: 2000-09-19
Classification: C08L

Abstract:
A crystalline propylene block-copolymer composition for use in automobile parts, comprising(A) 41 to 71% by weight of a crystalline propylene block-copolymer composed of a propylene homopolymer portion (Fp) and an ethylene/propylene random copolymer portion (Fc) and having an ethylene content of 1 to 10% by weight and a melt flow rate (MFR, determined at 230.degree. C. under a load of 2160 g) of 20 to 100 g/10 min.,(B) 12 to 22% by weight of a first hydrogenated product of a block-copolymer composed of blocks represented by the following formula (1) or (2), namely,X-Y (1)X(-Y-X).sub.n ( 2)in which X stands for a polymer block of a vinyl-mono-substituted aromatic hydrocarbon, Y stands for an elastomeric polymer block of a conjugated diene and n is an integer of 1 to 5, wherein the content of X amounts to 5 to 22% by weight and the melt flow rate (MFR) for the entire block-copolymer is 0.5 to 70 g/10 min. and wherein the hydrogenation degree is at least 90 mole %,(C) 2 to 12% by weight of a second hydrogenated product of a block-copolymer composed of blocks represented by the following formula (1) or (2), namely,X-Y (1)X(-Y-X).sub.n ( 2)in which X stands for a polymer block of a vinyl-mono-substituted aromatic hydrocarbon, Y stands for an elastomeric polymer block of a conjugated diene and n is an integer of 1 to 5, wherein the content of X amounts to 30 to 80% by weight and the melt flow rate (MFR) for the entire block-copolymer is 0.1 to 20 g/10 min. and wherein the hydrogenation degree is at least 90 mole %, and(D) 15 to 25% by weight of talc of a grade having an average particle size, determined by a laser beam diffraction method, of 1 to 5 .mu.m,wherein, in the crystalline propylene block-copolymer (A), the said propylene homopolymer portion (Fp) contains 20 to 50% by weight of a low molecular weight propylene homopolymer (Fh) having a melt flow rate (MFR, determined at 230.degree. C. under a load of 2160 g) of 400 to 1,000 g/10 min. and is constituted of a propylene homopolymer having an average melt flow rate (MFR, determined at 230.degree. C. under a load of 2160 g), for the entire propylene homopolymer portion (Fp), of 100 to 350 g/10 min. and an isotactic pentad fraction (mmmm), determined by .sup.13 C-NMR, of at least 98% and the said ethylene/propylene random copolymer portion (Fc) is constituted of an ethylene/propylene random copolymer having an intrinsic viscosity [.eta.], determined at 135.degree. C. in decalin, of 7 dl/g or higher.