Method for preparing a ziegler-natta catalyst system with improved performance in propylene polymerization
AssigneeFormosa Plastics Corporation, U.S.A.
InventorsLei ZHANG, Gapgoung Kong, Cyrus C.Y. Lee, Guangxue Xu
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Abstract
A method for preparing a Ziegler-Natta catalyst system, especially a phthalate-free catalyst system, with improved performance in propylene polymerization is provided. It is found that catalyst performance, especially catalyst activity and hydrogen response, is significantly improved when a propylene-based pre-polymer is prepared in the presence of a vinyldisilane compound and then used in propylene polymerization.
Claims14
A method for producing a propylene-based pre-polymer with improved performance in olefin polymerization, comprising:
- preparing a bare catalyst (C) by contacting a solid catalyst component (C1) comprising magnesium, titanium and a halogen, and a vinyldisilane compound (C2);
- and
- preparing the propylene-based pre-polymer (P) by contacting the bare catalyst (C) with propylene.
A method for producing a propylene-based pre-polymer with improved performance in olefin polymerization, comprising:
- preparing a bare catalyst (C) by contacting a solid catalyst component (C1) comprising magnesium, titanium and a halogen, a vinyldisilane compound (C2), an organoaluminum compound (C3), and an organosilicon compound (C4) comprising one or more Si—O—C or Si—N—C bonds;
- and
- preparing the propylene-based pre-polymer (P) by contacting the bare catalyst (C) with propylene.
A method for producing a propylene-based pre-polymer with improved performance in olefin polymerization, comprising:
- preparing a bare catalyst (C) by contacting a solid catalyst component (C1) comprising magnesium, titanium and a halogen, and a vinyldisilane compound (C2);
- and
- preparing the propylene-based pre-polymer (P) by contacting the bare catalyst (C) with propylene;
- wherein the vinyldisilane compound (C2) is represented by the formula:
- (CH2=CH—)m(R1)n(R2O—)kSi—Si(—CH═CH2)x(R3)y(—OR4)z
- wherein R1, R2, R3 and R4 are independently selected from a hydrocarbon group or a heteroatom-containing hydrocarbon group;
- wherein 1≤m≤3, 0≤n≤2, 0≤k≤2, 0≤x≤3, 0≤y≤3, 0≤z≤3;
- wherein m+n+k=3 and x+y+z=3;
- wherein R1 can be the same or different when n>1;
- wherein R3 can be the same or different when y>1;
- wherein R2 can be the same or different when k>1;
- and
- wherein R4 can be the same or different when z>1.
Dependencies are inferred from the claim text.