Self limiting catalyst composition and propylene polymerization process
View Patent ↗A catalyst composition for the polymerization of propylene comprising one or more Ziegler-Natta procatalyst compositions comprising one or more transition metal compounds and one or more esters of aromatic dicarboxylic acid internal electron donors; one or more aluminum containing cocatalysts; a selectivity control agent (SCA) comprising at least one silicon containing compound containing at least one C 1-10 alkoxy group bonded to a silicon atom, and one or more activity limiting agent (ALA) compounds comprising one or more aliphatic or cycloaliphatic carboxylic acids; alkyl-, cycloalkyl- or alkyl(poly)(oxyalkyl)-(poly)ester derivatives thereof; or inertly substituted derivatives of the foregoing.
1. A catalyst composition for the polymerization of propylene or mixtures of propylene and one or more copolymerizable comonomers, said catalyst composition comprising:
one or more Ziegler-Natta procatalyst compositions comprising one or more transition metal compounds and one or more esters of aromatic dicarboxylic acid internal electron donors;
one or more aluminum containing cocatalysts;
a selectivity control agent (SCA) comprising at least one silicon containing compound containing at least one C 1-10 alkoxy group bonded to a silicon atom;
one or more activity limiting agent (ALA) compounds of C 1-20 alkyl esters of aliphatic C 8-20 monocarboxylic acids and inertly substituted derivatives of the foregoing, said ALA compounds and amounts being selected such that the normalized polymerization activity of the catalyst composition at a temperature from 85 to 130° C., is less than the normalized polymerization activity of the catalyst composition in the presence of only the SCA compound at the same total molar quantity of SCA at said temperature; and the catalyst composition does not impart an undesirable odor to the polymer formed therefrom.
2. The catalyst composition according to claim 1 wherein the total quantity of selectivity control agent employed is limited to provide a molar ratio, based on transition metal, from 0.1 to 500.
3. A catalyst composition according to claim 1 wherein the SCA/ALA equivalent ratio is from 99/1 to 0.1/99.9.
4. The catalyst composition according to claim 1 wherein the selectivity control agent is selected from the group consisting of dicyclopentyldimethoxysilane, di-tert-butyldimethoxysilane, methylcyclohexyldimethoxysilane, ethylcyclohexyldimethoxysilane, diphenyldimethoxysilane, diisopropyldimethoxysilane, di-n-propyldimethoxysilane, diisobutyldimethoxysilane, di-n-butyldimethoxysilane, cyclopentyltrimethoxysilane, isopropyltrimethoxysilane, n-propyltrimethoxysilane, n-propyltriethoxysilane, ethyltriethoxysilane, tetramethoxysilane, tetraethoxysilane, cyclopentylpyrrolidinodimethoxysilane, bis(pyrrolidino)-dimethoxysilane, bis(perhydroisoquinolino)dimethoxysilane, and combinations thereof.
5. The catalyst composition according to claim 1 wherein the selectivity control agent is selected from the group consisting of dicyclopentyldimethoxysilane, methylcyclohexyldimethoxysilane, and n-propyltrimethoxysilane and the ALA is isopropyl myristate.
6. The catalyst composition according to claim 1 wherein the ALA is isopropyl myristate.
7. The catalyst composition according to claim 1 wherein the SCA is dicyclopentyldimethoxysilane and the ALA is isopropyl myristate.
8. The catalyst composition according to claim 1 wherein the SCA is dicyclopentyldimethoxysilane.
9. A catalyst composition comprising:
one or more Ziegler-Natta procatalyst compositions comprising one or more transition metal compounds and one or more esters of aromatic dicarboxylic acid internal electron donors;
one or more aluminum containing cocatalysts;
a selectivity control agent (SCA) comprising at least one silicon containing compound containing at least one C 1-10 alkoxy group bonded to a silicon atom; and
one or more activity limiting agent (ALA) compounds comprising isopropyl myristate.
10. The catalyst composition of claim 9 wherein the catalyst composition does not impart an undesirable odor to the polymer formed therefrom.
11. The catalyst composition of claim 9 wherein the SCA is selected from the group consisting of dicyclopentyldimethoxysilane, methylcyclohexyldimethoxysilane, and n-propyltrimethoxysilane.
12. The catalyst composition of claim 9 wherein the SCA is dicyclopentyldimethoxysilane.
13. A polymerization process comprising:
contacting propylene or a mixture of propylene and one or more copolymerizable comonomers under polymerization conditions at a temperature from 40 to 130° C. with a catalyst composition comprising a Ziegler-Natta procatalyst composition comprising a transition metal compound and an ester of aromatic dicarboxyic acid internal electron donor, an aluminum containing cocatalyst, a selectivity control agent (SCA) comprising at least one C 1-10 alkoxy ground bonded to a silicon atom, and a C 1-20 alkyl ester of an aliphatic C 8-20 monocarboxylic acid; and
forming a polymer without an undesired odor.
14. A process according to claim 13 which is a gas phase polymerization process.
15. A process according to claim 13 which is conducted in more than one reactor operating in series.