PURPOSE: To obtain a polypropylene resin composition having a well-balanced combination of impact resistance, rigidity, and heat resistance by compounding a specific mixed PP resin with an olefin rubber or another polyolefin.
CONSTITUTION: The composition comprises (A) 50-90 pts.wt. mixed PP consisting of 3-30wt.% PP which is insoluble in hot heptane but soluble in hot octane and has a weight-average mol.wt. of 5,000-1,000,000 and in which the content of pentads each made up of five propylene units bonded through meso bonds only is 70% or higher and the content of pentads each made up of propylene units bonded through racemic bonds only is 5% or higher and 70-95wt.% ultrahighly wstereoregular PP which has a melt flow rate of 0.1-1,000g/10min and in which the meso-average chain length, Nm, calculated from the triad contents using equation I satisfies relationship II, (B) 50-10 pts.wt. at least either an olefin rubber or a polyolefin other than the PPs, and (C) an inorganic filler in an amount of up to 40 pts.wt. per 100 pts.wt. the sum of the components (A) and (B).
OKURA MASATOSHI
UEKI SATOSHI
TOKI SHIGEYUKI
NISHIO TAKESUMI
NOMURA TAKAO
TOYOTA MOTOR CORP