Catalyst composition with mixed selectivity control agent and method
AssigneeW. R. Grace & Co.-Conn.
InventorLinfeng Chen
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Abstract
The present disclosure provides a Ziegler-Natta catalyst composition comprising a procatalyst, a cocatalyst and a mixed external electron donor comprising a first selectivity control agent, a second selectivity control agent, and an activity limiting agent. A polymerization process incorporating the present catalyst composition produces a high-stiffness propylene-based polymer with a melt flow rate greater than about 50 g/10 min. The polymerization process occurs in a single reactor, utilizing standard hydrogen concentration with no visbreaking.
Claims17
A propylene-based polymer comprising:
- dicyclopentyldimethoxysilane, an ethoxysilane, and at least about 5 ppm to about 150 ppm of an activity limiting agent (ALA) comprising a C4-C30 aliphatic acid monoester, polymer wherein a mole ratio of dicyclopentyldimethoxysilane to ethoxysilane is 0.1-1:1, the propylene-based polymer:
- (A) having a melt flow rate greater than about 100 g/10 min as measured in accordance with ASTM D 1238-01 at 230° C., 2.16 kg;
- (B) having a xylene solubles content of from 0.1 weight percent to less than 2 weight percent;
- (C) exhibiting a TMF greater than about 165° C.;
- (D) wherein the ratio of combined moles of dicyclopentyldimethoxysilane and ethoxysilane to moles of activity limiting agent is about 0.43-2.33:1;
- and
- (E) wherein the mole ratio of dicyclopentyldimethoxysilane to combined moles of dicyclopentyldimethoxysilane and ethoxysilane is about 0.2-0.5:1.
A propylene-based polymer comprising:
- dicyclopentyldimethoxysilane, an ethoxysilane, and at least about 5 ppm to about 150 ppm of an activity limiting agent (ALA) comprising a C4-C30 aliphatic acid monoester, wherein a mole ratio of dicyclopentyldimethoxysilane to ethoxysilane is 0.1-1:1, wherein the ethoxysilane is selected from the group consisting of a diethoxysilane, a tetraethoxysilane, and combinations thereof, the propylene-based polymer:
- (A) having a melt flow rate greater than about 100 g/10 min as measured in accordance with ASTM D 1238-01 at 230° C., 2.16 kg;
- (B) having a xylene solubles content of from 0.1 weight percent to less than 2 weight percent;
- (C) exhibiting a TMF greater than about 165° C.;
- (D) wherein the ratio of combined moles of dicyclopentyldimethoxysilane and ethoxysilane to moles of activity limiting agent is about 0.43-2.33:1;
- and
- (E) wherein the mole ratio of dicyclopentyldimethoxysilane to combined moles of dicyclopentyldimethoxysilane and ethoxysilane is about 0.2-0.5:1.
A propylene-based polymer comprising:
- dicyclopentyldimethoxysilane, an ethoxysilane, wherein a mole ratio of dicyclopentyldimethoxysilane to ethoxysilane is 0.1-1:1, and at least about 5 ppm to about 150 ppm of an activity limiting agent (ALA) comprising a C4-C30 aliphatic acid monoester, the propylene-based polymer:
- (A) having a melt flow rate greater than 100 g/10 min as measured in accordance with ASTM D 1238-01 at 230° C., 2.16 kg;
- (B) having a xylene solubles content of from 0.1 weight percent to less than 2 weight percent;
- (C) exhibiting a TMF greater than about 165° C.;
- (D) wherein the ratio of combined moles of dicyclopentyldimethoxysilane and ethoxysilane to moles of activity limiting agent is about 0.43-2.33:1;
- and
- (E) wherein the mole ratio of dicyclopentyldimethoxysilane to combined moles of dicyclopentyldimethoxysilane and ethoxysilane is about 0.2-0.5:1.
Dependencies are inferred from the claim text.