Process for producing propylene copolymers

Abstract

In a process for producing a propylene copolymer, propylene and at least one olefin monomer selected from ethylene and alpha olefins having 4 to 20 carbon atoms are contacted with a catalyst system comprising (a) a catalyst precursor comprising an organometallic compound and (b) an activator comprising a fluoroarylborate anion represented by the formula:

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a graph of copolymer molecular weight versus the number, n, of perfluoronaphthyl (C₁₀F₇) ligands on an activator anion having the formula (C₆F₅)_4-n(C₁₀F₇)_n⁻ for the ethylene/propylene polymerization runs of Examples 4 to 7 using a precatalyst comprising μ-dimethylsilyl(bis-indenyl)hafnium dimethyl (Catalyst A) and the activator Ct⁺(C₆F₅)_4-n(C₁₀F₇)_n⁻ where Ct⁺is the dimethylanilinium cation.

FIG. 2 is a graph comparing the activity of the polymerization catalyst A, averaged over x number of runs, with the number, n, of perfluoronaphthyl (C₁₀F₇) ligands on the activator Ct⁺(C₆F₅)_4-n(C₁₀F₇)_n⁻ for the ethylene/propylene polymerization runs of Examples 4 to 7.

FIG. 3 is a graph of copolymer molecular weight versus the number, n, of perfluoronaphthyl (C₁₀F₇) ligands on an activator anion having the formula (C₆F₅)_4-n(C₁₀F₇)_n⁻ for the ethylene/propylene polymerization runs of Examples 8 to 17.

Claims

1. A process for producing a propylene copolymer comprising contacting propylene and at least one olefin monomer selected from ethylene and alpha olefins having 4 to 20 carbon atoms with a catalyst system comprising (a) a catalyst precursor comprising an organometallic compound and (b) an activator comprising a fluoroarylborate anion represented by the formula: Ct+[B—(ArxRn)]−

2. The process of claim 1 wherein Ar is a perfluorophenyl.

3. The process of claim 1 wherein R is a perfluoronaphthyl.

4. The process of claim 1 wherein x is 1 and n is 3.

5. The process of claim 1 wherein x is 2 and n is 2.

6. The process of claim 1 wherein x is 3 and n is 1.

7. The process of claim 1 wherein an activator comprises at least one of the anions:

8. The process of claim 1 wherein Ct+ is selected from silylium, trityl carbenium, Group-12 metal, anilinium, ammonium, phosphonium, and arsonium cations, and anilinium, ammonium, phosphonium, and arsonium cationic derivatives wherein the cationic derivatives contain C1 to C30 hydrocarbyl, hydrocarbylsilyl, or hydrocarbyl-amine substituents for one or more cation hydrogen atoms.

9. The process of claim 1 wherein said at least one olefin monomer is ethylene.

10. The process of claim 9 wherein said propylene copolymer contains units derived from propylene in an amount greater than or equal to 65 weight percent, and units derived from ethylene in an amount of from 5 to 35 weight percent.

11. The process of claim 1 wherein said catalyst precursor is selected from a metallocene catalyst precursor, a bisamide catalyst precursor, an amine bisamide catalyst precursor, or a pyridine bisamide catalyst precursor.

12. The process of claim 1 wherein said catalyst system is capable of producing stereoregular polypropylene.

13. The process of claim 1 wherein said catalyst precursor is a metallocene catalyst precursor.

14. The process of claim 13 wherein said metallocene catalyst precursor is selected from pentamethylcyclopentadienyltitanium isopropoxide, pentamethylcyclopentadienyltribenzyl titanium, dimethylsilyltetramethylcyclopentadienyl-tert-butylamido titanium dichloride, pentamethylcyclopentadienyl titanium trimethyl, dimethylsilyltetramethylcyclopentadienyl-tert-butylamido zirconium dimethyl, dimethylsilyltetramethylcyclopentadienyl-dodecylamido hafnium dihydride, dimethylsilyltetramethylcyclopentadienyl-dodecylamido hafnium dimethyl, bis(1-methyl-3-butylcyclopentadienyl)zirconium dimethyl, pentamethylcyclopentadienyl-cyclopentadienyl zirconium dimethyl, (tetramethylcyclopentadienyl)(n-propylcyclopentadienyl)zirconium dimethyl, dimethylsilylbis(tetrahydroindenyl)zirconium dichloride, silacyclobutyl(tetramethylcyclopentadienyl)(n-propyl-cyclopentadienyl)zirconium dimethyl, dimethylsilylbisindenyl zirconium dichloride, dimethylsilylbisindenyl hafnium dimethyl, dimethylsilylbis(2-methylindenyl)hafnium dimethyl, dimethylsilylbis(2-methylindenyl)zirconium dimethyl, dimethylsilylbis(2-methyl-4-phenylindenyl)hafnium dimethyl, dimethylsilylbis(2-methyl-4-phenylindenyl)zirconium dimethyl, dimethylsilylbis(2-methylbenzindenyl)zirconium dichloride, dimethylsilylbis(2-methylbenzindenyl)zirconium dimethyl, diphenylmethyl(fluorenyl)(cyclopentadienyl)zirconium dimethyl and di(para-triethylsilylphenyl)methylene(2,7-ditert-butylfluorenyl) (cyclopentadienyl)hafnium dimethyl.

15. A propylene copolymer produced by the process of claim 1.

16. A blend comprising a copolymer according to claim 15 and another polymer.

17. The blend according to claim 16 wherein the other polymer is polypropylene homopolymer.

18. An injection molded article, fiber, film or non-woven article comprising the copolymer of claim 15.

19. An injection molded article, fiber, film or non-woven article comprising the polymer blend of claim 16.