PURPOSE: To obtain a propylene-α-olefin block copolymer having low adhesivity as polymer particles and excellent powder properties.
CONSTITUTION: This propylene-α-olefin block copolymer is produced using a high active stereoregular-polymerization catalyst, in the state essentially free from a solvent. The polymerization is carried out in three stages. In the first stage, a propylene homopolymer or a propylene-α-olefin copolymer wherein the content of another α-olefin than propylene is ≤5wt.%, is produced within the range of 25-93wt.% of the total polymer weight. In the second stage, a propylene-α-olefin copolymer wherein the content of the ct-olefin is 5-10wt.% is produced in 2-10wt.% of the total polymer weight. In the third stage, a propylene-α-olefin copolymer wherein the content of the α-olefin is 10-90wt.% is produced in 5-65wt.% of the total polymer weight.
KATO HIDETO
MIZUTA MASAO
TANAKA HIDEAKI
