Self limiting catalyst composition and propylene polymerization process

1. A catalyst composition comprising:

a procatalyst composition;

a cocatalyst;

a selectivity control agent (SCA) comprising one or more silicon containing compounds; and

an activity limiting agent (ALA) selected from the group consisting of distearyl 3,3-thiodipropionate, butanedioic acid polymer with 4-hydroxy-2,2,6,6-tetramethyl-1-piperidineethanol, bis(2,2,6,6,-tetramethyl-4-piperidyl)sebacate, pentaerythritol tetrakis[3-(3′,5′-di-t-butyl-4′-hydroxyphenyl)propionate], and combinations thereof.

2. The catalyst composition of claim 1 wherein the ALA comprises distearyl-3,3-thiodipropionate.

3. The catalyst composition of claim 1 wherein the ALA comprises butanedioic acid polymer with 4-hydroxy-2,2,6,6-tetramethyl-1-piperidineethanol.

4. The catalyst composition of claim 1 wherein the ALA comprises bis(2,2,6,6,-tetramethyl-4-piperidyl)sebacate.

5. The catalyst composition of claim 1 wherein the ALA comprises pentaerythritol tetrakis[3-(3′,5′-di-t-butyl-4′-hydroxyphenyl)propionate].

6. The catalyst composition of claim 1 wherein the SCA comprises dicyclopentyldimethoxysilane.

7. The catalyst composition of claim 1 wherein the SCA comprises a member selected from the group consisting of methylcyclohexyldimethoxysilane and n-propyltrimethoxysilane.

8. A catalyst composition comprising:

a procatalyst composition;

a cocatalyst;

a selectivity control agent (SCA) comprising one or more silicon containing compounds; and

an activity limiting agent (ALA) comprising a C 2-20 alkyl monocarboxylate derivative of a C 2-100 (poly)polyglycol ether.

9. The catalyst composition of claim 8 wherein the ALA comprises (poly)(ethylene glycol) methyl ether laurate.

10. The catalyst composition of claim 8 wherein the SCA comprises dicyclopentyldimethoxysilane.

11. The catalyst composition of claim 8 wherein the SCA comprises methylcyclohexyldimethoxysilane.

12. The catalyst composition of claim 8 wherein the SCA comprises n-propyltrimethoxysilane.

13. A catalyst composition comprising:

one or more Ziegler-Natta procatalyst compositions;

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.

14. The catalyst composition of claim 13 comprising an SCA/ALA mixture comprising 1 to 99.9 wt % ALA and 99 to 0.1 wt % SCA.

15. The catalyst composition of claim 13 comprising an SCA/ALA mixture comprising 30 to 99 wt % ALA and 70 to 1 wt % SCA.

16. The catalyst composition of claim 13 comprising an SCA/ALA mixture comprising 50 to 98 wt % ALA and 50 to 2 wt % SCA.

17. The catalyst composition of claim 13 wherein the SCA comprises dicyclopentyldimethoxysilane.

18. The catalyst composition of claim 13 wherein the SCA comprises methylcyclohexyldimethoxysilane.

19. The catalyst composition of claim 13 wherein the SCA comprises n-propyltrimethoxysilane.

20. The catalyst composition of claim 13 wherein the ALA comprises isopropyl myristate.