Propylene-based resin composition

• Main Authors: SOBAJIMA, YOSHIHIRO, HAYAKAWA, YUU, BANNO, YOSHIHIRO
• Format: Patent
• Language: English
• Published: 21.12.2002
• Edition: 7
• Subjects: CHEMISTRY; COMPOSITIONS BASED THEREON; COMPOSITIONS OF MACROMOLECULAR COMPOUNDS; METALLURGY; ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; USE OF INORGANIC OR NON-MACROMOLECULAR ORGANIC SUBSTANCES ASCOMPOUNDING INGREDIENTS

A new propylene-based resin composition exhibits excellent in injection moldability (or injection compression moldability), showing well-balanced properties (in terms of high rigidity, impact strength and surface hardness), excellent in resistance to weather, and, in particular, suitable for a variety of members for industrial devices, particularly interior members for automobiles. Namely the present invention provides a propylene-based resin composition, comprising: (a) 100 wt.parts of a propylene/ethylene block copolymer comprising 60 to 78 wt.% of a crystalline polypropylene homopolymer portion (unit A) and 22 to 40 wt.% of an ethylene/propylene random copolymer portion (unit B), containing ethylene at 30 to 52 wt.% and having a weight-average molecular weight (Mw) of 230,000 to 600,000, the whole composition (a) having a melt flow rate (MFR at 230 DEG C and 2.16 kg) of 25 to 40 g/10 min and number of 100 or less gels for gel size of 50 m or more in a molded article, 25 cm2 in area and 0.5 mm in thickness, (b) 1 to 8 wt.parts of an ethylene/ -olefin copolymer rubber, containing an -olefin having a carbon number of 4 to 8 at 20 to 50 wt.% and having an MFR of 0.5 to 15 g/10 min, (c) 0.01 to 2 wt.parts of a hindered amine compound having a molecular weight of 450 or more, (d) 0 to 2 wt.parts of a nucleating agent, and (e) 0 to 6 wt.parts of talc having an average particle size of 1.5 to 15 m.