To provide a polypropylene with an excellent elasticity, particularly excellent in highly controlled stereoregularity, and a production method therefor, wherein the polypropylene can be used for various molded articles having very good flexibility, little stickiness, and excellent heat resistance and transparency, as well as excellent elastic recovery.
This propylene homopolymer is characterized in that the isotactic pentad ratio (mmmm) is 0.20-0.55, the triad chain fractions: mm, rr and mr are in a relationship of mm>rr>mr, the ratio of the mole number of a propylene unit derived from 2,1-insertion reaction of propylene monomer, and the ratio of the mole number of a propylene unit derived from 1,3-insertion reaction of propylene monomer, to the total mole number of the propylene units constituting the propylene homopolymer, are <0.2%, respectively, and niso is 5-30, the niso being calculated by the equation: niso=DP/(1+DP.(Pmrrm+ P1-3+P2-1)).
HACHIMAN GOJI
OKI YOSHIYUKI
CHISSO SEKIYU KAGAKU KK
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