Process for production of high melt flow propylene-based polymer and product from same
View Patent ↗Disclosed are catalyst compositions having an internal electron donor which includes a 3,6-di-substituted-1,2-phenylene aromatic diester. Ziegler-Natta catalyst compositions containing the present catalyst compositions exhibit very high hydrogen response, high activity, high selectivity and produce propylene-based olefins with high melt flow rate.
1. A Ziegler-Natta polymerization process for producing a propylene-based polymer comprising:
(A) contacting, under polymerization conditions and in the presence of hydrogen gas (H 2 ), propylene and optionally one or more comonomers with a catalyst composition comprising:
(i) a procatalyst composition comprising a substituted-1,2-phenylene dibenzoate having structure (I),
wherein R 1 -R 14 are the same or different, each of R 1 and R 4 is selected from the group consisting of a C 1 -C 8 alkyl group, a C 2 -C 8 alkenyl group, and combinations thereof, each of R 2 and R 3 is selected from the group consisting of hydrogen and a hydrocarbyl group having 1 to 20 carbon atoms, and each of R 5 -R 14 is selected from hydrogen, a halogen, a hydrocarbyl group having 1 to 20 carbon atoms, and a hydrocarbyloxy group having 1 to 20 carbon atoms,
(ii) a cocatalyst, and
(iii) an external electron donor;
(B) maintaining a H 2 /propylene mole ratio from 0.005 to less than 0.1 during the contacting; and
(C) forming a propylene-based polymer having a melt flow rate greater than 50 g/10 min,
wherein the polymerization process is selected from the group consisting of gas phase, slurry, and a bulk polymerization, operating in one or more than one reactor.
2. The process of claim 1 comprising maintaining a H 2 /propylene mole ratio from 0.03 to less than 0.1 during the contacting; and
forming a propylene-based polymer having a melt flow rate greater than 100 g/10 min.
3. The process of claim 1 wherein at least one of R 1 and R 4 is a methyl group.
4. The process of claim 1 wherein each of R 1 and R 4 is a methyl group.
5. The process of claim 1 wherein R 1 is a methyl group and R 4 is an isopropyl group.
6. The process of claim 1 wherein each of R 1 and R 4 is a methyl group, R 3 is hydrogen, and R 2 is selected from the group consisting of an isopropyl group, a cyclopentyl group, a cyclohexyl group, an aryl group, an alkylaryl group, a tert-butyl group, and a 2,3,3-trimethylbutan-2-yl group.
7. The process of claim 1 wherein each of R 1 and R 4 is a methyl group and R 2 is an isopropyl group.
8. The process of claim 1 comprising forming a propylene homopolymer having a melt flow rate greater than 100 g/10 min.
9. The process of claim 1 wherein the catalyst composition comprises an activity limiting agent selected from the group consisting of a carboxylic acid ester, a diether, a poly(alkene glycol), poly(alkene glycol)ester, a diol ester, and combinations thereof.
10. The process of claim 1 wherein the catalyst composition comprises a first selectivity control agent (SCA1), that is a dimethoxysilane and a second selectivity control agent (SCA2) selected from the group consisting of a diethoxysilane, a triethoxysilane, a tetraethoxysilane, a trimethoxysilane, and a dimethoxysilane containing two linear alkyl or alkenyl groups or hydrogen.
11. The process of claim 1 comprising forming a propylene-based polymer having a xylene solubles content from 1 wt % to 4 wt %.
12. A Ziegler-Natta polymerization process for producing a propylene-based polymer comprising:
(A) contacting, under polymerization conditions and in the presence of hydrogen gas (H 2 ), propylene and optionally one or more comonomers with a catalyst composition comprising:
(i) a procatalyst composition comprising a substituted-1,2-phenylene dibenzoate having structure (I),
wherein R 1 -R 14 are the same or different, each of R 1 and R 4 is selected from the group consisting of a C 1 -C 8 alkyl group, a C 2 -C 8 alkenyl group, and combinations thereof, each of R 2 and R 3 is selected from the group consisting of hydrogen and a hydrocarbyl group having 1 to 20 carbon atoms, and each of R 5 -R 14 is selected from hydrogen, a halogen, a hydrocarbyl group having 1 to 20 carbon atoms, and a hydrocarbyloxy group having 1 to 20 carbon atoms,
(ii) a cocatalyst, and
(iii) an external electron donor;
(B) maintaining a H 2 /propylene mole ratio from 0.005 to less than 0.1 during the contacting; and
(C) forming a propylene-based polymer having a melt flow rate greater than 200 g/10 min
wherein the polymerization process is selected from the group consisting of gas phase, slurry, or a bulk polymerization, operating in one or more than one reactor.