Patent ID: 10815319

Abstract:
The invention relates to a production method of a heterophasic propylene polymerization material containing a propylene homopolymer (I-1) or a propylene copolymer (I-2), and a propylene copolymer (II), wherein the content of the propylene copolymer component (II) is 30% by weight or more, the production method containing the following steps (1) and (2):Step (1): a step of polymerizing a monomer containing propylene in the presence of a catalyst for propylene polymerization to produce a propylene homopolymer (I-1) or a propylene copolymer (I-2), the step satisfying the formula (A): 1100≤α(1.34β)1/3  (A) wherein, α represents the median diameter (unit: μm) of the catalyst for propylene polymerization and β represents the production amount (unit: g/g) of the propylene homopolymer (I-1) or the propylene copolymer (I-2) per 1 g of the catalyst for propylene polymerization in the step (1); Step (2): a step of copolymerizing at least one olefin selected from the group consisting of ethylene and α-olefins having the number of carbon atoms of 4 or more and 12 or less, and propylene in the presence of the propylene homopolymer (I-1) or the propylene copolymer (I-2) obtained in the step (1), using 1 or more gas phase polymerization reactors, to produce a propylene copolymer (II), wherein the concentration of alkanes having the number of carbon atoms of 6 or more in the final gas phase polymerization reactor of the 1 or more gas phase polymerization reactors is 0.01% by volume or more and 0.6% by volume or less.