Polyolefin-based plastic composition and automotive molded article formed thereof

An automotive molded article having a Flexural Elastic Modulus not lower than 1960 MPa, and an IZOD not lower than 0.088 KJ/m, and a Rockwell hardness (in R scale) not lower than 65, said molded article being formed of a polyolefin-based plastic composition comprising:

• (A) block copolymer in an amount ranging from 53 to 68 parts by weight, said block copolymer having a Melt Flow Rate (at 230.degree. C. and under 2.16 kg) ranging from 20 to 50 g/10 min. and containing crystalline polypropylene section in an amount ranging from 90 to 95% by weight, having a density of not lower than 0.908 g/cm.sup.3, and propylene-ethylene random copolymer section in an amount ranging from 5 to 10% by weight, said propylene-ethylene random copolymer section having an ethylene content ranging from 35 to 45% by weight;
• (B) ethylene-1-butene copolymer rubber in an amount ranging from 12 to 20 parts by weight and having a density ranging from 0.85 to 0.87 g/cm.sup.3 and a Melt Flow Rate (at 230.degree. C. and under 2.16 kg) ranging from 0.2 to 5 g/10 min., said copolymer rubber containing 1-butene in an amount ranging from 30 to 40% by weight;
• and
• (C) talc in an amount ranging from 22 to 30 parts by weight and having a length not more than 15 .mu.m and an average particle size ranging from 1.5 to 6 .mu.m, said talc having an average aspect ratio not lower than 5.

A polyolefin-based plastic composition consisting essentially of:

• (A) a block copolymer in an amount ranging from 53 to 68 parts by weight, said block copolymer having a Melt Flow Rate (at 230.degree. C. and under 2.16 Kg) ranging from 20 to 50 g/10 min, and containing a crystalline polypropylene section (I) in an amount ranging from 90 to 95% by weight, having a density of not lower than 0.902 g/cm.sup.3, and a propylene-ethylene random copolymer section (II) in an amount ranging from 5 to 10% by weight, said propylene-ethylene random copolymer section (II) having an ethylene content ranging from 35 to 45% by weight;
• (B) ethylene-1-butene copolymer rubber in an amount ranging from 12 to 20 parts by weight and having a density ranging from 0.85 to 0.87 g/cm.sup.3 and a Melt Flow Rate (at 230.degree. C. and under 2.16 kg) ranging from 0.2 to 5 g/10 min., said copolymer rubber containing 1-butene in an amount ranging from 30 to 40% by weight;
• and
• (C) talc in an amount ranging from 22 to 30 parts by weight and having a length not more than 15 .mu.m and an average particle size ranging from 1.5 to 6 .mu.m, said talc having an average aspect ratio not lower than 5;
• where said polyolefin-based plastic composition has a Melt Flow Rate (at 230.degree. C. and under 2.16 kg) not lower than 8 g/10 min, a Flexural Elastic Modulus not lower than 1960 MPa when molded, an IZOD not lower than 0.088 KJ/m when molded, and a Rockwell hardness (in R scale) not lower than 65 when molded.