Disclosed are a propylene polymer composition possessing excellent balance
among rigidity and low warpage, resistance to deterioration caused by
thermal oxidation during processing, weathering resistance, antistatic
properties, and low bleeding properties, and a propylene resin composition
which can easily produce molded products having excellent balance between
rigidity and impact resistance (particularly low-temperature impact
resistance) or heat resistance. The propylene polymer composition and the
propylene resin composition comprise a propylene block copolymer
consisting essentially of the following blocks (a) and (b) and having a
melt flow rate of 0.1 to 200 g/10 min:
block (a): a polymer block of a homopolymer of propylene or a random
copolymer of propylene with a comonomer selected from the group consisting
of ethylene and C.sub.4 -C.sub.20 .alpha.-olefins, the content of the
comonomer being not more than 10% by mole; and
block (b): a polymer block of a random copolymer of propylene with at least
one comonomer selected from the group consisting of ethylene and C.sub.4
-C.sub.20 .alpha.-olefins, the content of the comonomer being 10 to 80% by
mole, the average chain length of the comonomer block and the gross
average chain length of the comonomer having a relationship represented by
formula (I)
n.sub.b.ltoreq.n+1.5 (I)
wherein n.sub.b represents the average chain length of the comonomer block;
and n represents the gross average chain length of the comonomer.
