Disclosed are a propylene
polymer having a high
crystallinity of a boiled
heptane-insoluble component contained therein, a high stereoregularity and an extremely long mesochain (continuous propylene units wherein directions of alpha-methyl carbons are the same as each other), and a process for preparing said
polymer. Also disclosed are a propylene block
copolymer containing a crystalline
polypropylene portion having a high
crystallinity of a boiled
heptane-insoluble component contained therein, a high stereoregularity and an extremely long mesochain, and a process for preparing said
copolymer. Further disclosed is a propylene
polymer composition comprising the above propylene polymer or propylene block
copolymer and at least one stabilizer selected from a
phenol type stabilizer, an organophosphite type stabilizer, a
thioether type stabilizer, a hindered amine type stabilizer and a metallic salt of higher aliphatic acid. The propylene polymer of the invention is excellent in rigidity,
heat resistance and
moisture resistance, and can be favorably used for sheet, film, filament, injection molded product, blow molded product, etc. The propylene block polymer of the invention is well-balanced between rigidity,
heat resistance and
moisture resistance, and can be favorably used for sheet, filament, injection molded product, blow molded product, etc. The propylene
polymer composition of the invention has excellent properties of the propylene polymer or the propylene block copolymer, and moreover is excellent in
heat stability during the molding stage, long-term
heat stability and
weathering resistance. The propylene
polymer composition can be favorably used for sheet, film, filament, injection molded product, blow molded product, etc.