Process for the preparation of high purity propylene polymers

  • US 10,221,261 B2
  • Filed: 09/17/2012
  • Issued: 03/05/2019
  • Est. Priority Date: 09/23/2011
  • Status: Active Grant
First Claim
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1. A low ash process for the preparation of a high purity propylene copolymer comprising copolymerizing propylene in the presence of a catalyst system comprising:

  • (a) a solid catalyst component comprising Mg, Ti, a first internal electron donor compound (1ID) comprising a succinate and a second internal electron donor compound (2ID) comprising a 1,3-diether, wherein the molar ratio of the first internal donor compound and the second internal donor compound 1ID;

    2ID is from 4;

    6-9;

    1 and the solid catalyst component comprising an average particle size of 25-65 μ

    m; and

    (b) an organo-aluminum compound;

    wherein the process is carried out at a temperature equal to or higher than 78°

    C. with a weight ratio of organo-aluminum compound to propylene from 0.005-0.020 kg/ton, and wherein the propylene copolymer comprises an Mw/Mn greater than 6.0, a rheological polydispersity index (PI) greater than 3.5, an isotacticity greater than 98.0%, a Mg content lower than 2 ppm, a Cl content lower than 5 ppm, a Ti content lower than 1 ppm, and an Al content lower than 3 ppm.

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