Propylene polymer compositions.

摘要

The propylene polymer composition of the invention comprises, as its essential components, a specific propylene polymer [A] described below and a propylene block copolymer [B]. In addition to the propylene polymer [A] and the propylene block copolymer [A], the propylene polymer composition may contain a thermoplastic elastomer [C] selected from polystyrene.polyethylene/poybutylene.polystyrene block copolymers and ethylene/ alpha -olefin random copolymers, or may further contain an inorganic filler [D]. The propylene polymer [A] used in the invention has the following characteristic properties: (1) a boiling heptane-insoluble component is contained in said polymer in an amount of not less than 96 % by weight, (2) a pentad isotacticity [M5] of the boiling heptane-insoluble component obtained from the following formula (1) using a <1><3>C-NMR spectrum is in the range of 0.970 to 0.995: <MATH> (3) a pentad tacticity [M3] of the boiling heptane-insoluble component obtained from the following formula (2) using a <1><3>C-NMR spectrum is in the range of 0.0020 to 0.0050: <MATH> and (4) a melt flow rate (MFR) of said polymer is in the range of 5 to 50 g/10 min. The propylene polymer compositions of the invention are excellent in both of rigidity and impact strength.