Thermoplastic resin composition and injection-molded object thereof

• Main Authors: MORIYASU SHIMOJO, SUSUMU KANZAKI, HISAYUKI IWAI, TAKAYUKI NAGAI, TAKAO NOMURA, KENICHI OHKAWA, MASATOSHI MATSUDA
• Format: Patent
• Language: English
• Published: 10.11.2000
• Edition: 7
• Subjects: AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F,C08G; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING; CHEMISTRY; COMPOSITIONS BASED THEREON; COMPOSITIONS OF MACROMOLECULAR COMPOUNDS; GENERAL PROCESSES OF COMPOUNDING; METALLURGY; ORGANIC MACROMOLECULAR COMPOUNDS; PERFORMING OPERATIONS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDEDFOR; SHAPING OR JOINING OF PLASTICS; THEIR PREPARATION OR CHEMICAL WORKING-UP; TRANSPORTING; USE OF INORGANIC OR NON-MACROMOLECULAR ORGANIC SUBSTANCES ASCOMPOUNDING INGREDIENTS; WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE, IN GENERAL; WORKING-UP

A thermoplastic composition which is obtained by melt-kneading (1) 55 to 75 wt.% crystalline polypropylene resin together with (2) 10 to 30 wt.% elastomer comprising either a rubber containing a vinylaromatic compound or a mixture thereof with an ethylene/ alpha -olefin random copolymer rubber and (3) 15 to 25 wt.% talc having an average particle diameter of 3 mu m or smaller. The composition satisfies specific requirements with respect to: the long period obtained by X-ray small-angle scattering attributable to the vinylaromatic-containing rubber in a blend obtained by melt-kneading the ingredients (1) and (2); the shape and diameter of the elastomer particles present near the polypropylene/elastomer interface in the blend; and the difference between the glass transition point of the ingredient (1) and that of the composition attributable to the crystalline polypropylene homopolymer parts. The composition has a satisfactory balance between impact resistance and rigidity and has excellent injection moldability.