POLYPROPYLENE RESIN COMPOSITION, PRECISION-INJECTION-MOLDED OBJECT, MOLD FOR MOLDING OPTICAL MEMBER, AND PROCESS FOR PRODUCING OPTICAL MEMBER

摘要

Disclosed is a polypropylene resin composition which contains a polypropylene-based polymer containing, as monomer units, propylene and at least one copolymerization monomer of ethylene or α-olefins with carbon atom number of 4 or more. Proportion of the monomer units derived from the copolymerization monomer in the polypropylene-based polymer is 2 to 10% by mass based on the mass of the polypropylene-based polymer. A crystallization half-time at 110° C. of the polypropylene resin composition is 20 seconds or shorter.