Patent ID: 8158706
Filing Date: 2012-04-17
Classification: C08L

Abstract:
1. A process of producing a polypropylene resin composition, comprising: preparing a moldability improver (A) and a polypropylene resin (B) separately; and blending 2 to 15 wt % of the moldability improver (A) and 85 to 98 wt % of the polypropylene resin (B) based on the total weight of the polypropylene resin composition, the moldability improver (A) containing 80 to 95 wt % of a propylene block copolymer (A-1) and 5 to 20 wt % of a propylene block copolymer (A-2) based on the total weight of the moldability improver (A), the propylene block copolymer (A-1) including 80 to 95 wt % of a crystalline propylene polymer component (A-11) and 5 to 20 wt % of a propylene-ethylene random copolymer component (A-12) based on the total weight of the propylene block copolymer (A-1) and satisfying the following properties: (a-11) the crystalline propylene polymer component (A-11) has a melt flow rate of 300 g/10 minutes or higher; (a-12) the propylene-ethylene random copolymer component (A-12) has an ethylene content of 20 to 70 wt %; (a-13) the propylene-ethylene random copolymer component (A-12) has an intrinsic viscosity of 6.5 dl/g or higher; and (a-14) the propylene block copolymer (A-1) has an overall melt flow rate of 80 g/10 minutes or higher, the propylene block copolymer (A-2) including 30 to 65 wt % of a crystalline propylene polymer component (A-21) and 35 to 70 wt % of a propylene-ethylene random copolymer component (A-22) based on the total weight of the propylene block copolymer (A-2) and satisfying the following properties: (a-21) the crystalline propylene polymer component (A-21) has a melt flow rate of 20 g/10 minutes or higher; (a-22) the propylene-ethylene random copolymer component (A-22) has an ethylene content of 20 to 70 wt %; (a-23) the propylene-ethylene random copolymer component (A-22) has an intrinsic viscosity of 4.0 to 9.0 dl/g or higher; and (a-24) the propylene block copolymer (A-2) has an overall melt flow rate of 0.1 to 79 g/10 minutes, the polypropylene resin (B) containing 55 to 85 wt % of a propylene-ethylene block copolymer (B-1), 5 to 20 wt % of at least one of an ethylene elastomer and a styrene elastomer, (B-2) and 10 to 25 wt % of an inorganic filler (B-3) based on the total weight of the polypropylene resin (B), the propylene-ethylene block copolymer (B-1) including less than 35 wt % of a propylene-ethylene random copolymer, component (B-12) based on the total weight of the propylene-ethylene block copolymer (B-1), the inorganic filler (B-3) being either talc, mica, glass fiber or whisker.