| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for producing a propylene-based block copolymer in which the stickiness or bleedout is suppressed. SOLUTION: The method etc., for producing the propylene-based block copolymer are carried out by successively polymerizing a propylene-based polymer component (A) using a supported metallocene catalyst in a first step and polymerizing a propylene-α-olefin random copolymer component (B) having a higher content of theα-olefin than that of the propylene-based polymer component (A) in a second step. In the method, the following (i) to (iv) are satisfied: (i) the average particle diameter of polymer particles during starting of the second step is≥700μm, (ii) the ratio of the copolymer component (B) [W(B)] to the total amount of the copolymer is 3-95 mass%, (iii) theα-olefin content [E(B)] of the copolymer component (B) is 3-90 mass% and (iv) the melting point [Tm(A)] of the propylene-based polymer component (A) is <143°C. COPYRIGHT: (C)2008,JPO&INPIT
|
