Silica-coated alumina activator-supports for metallocene catalyst compositions

Patent metadata

Field	Value
Publication number	US-10239975-B2
Application number	US-201715494674-A
Country	US
Kind code	B2
Filing date	Apr 24, 2017
Priority date	Mar 20, 2008
Publication date	Mar 26, 2019
Grant date	Mar 26, 2019

Abstract

Silica-coated alumina activator-supports, and catalyst compositions containing these activator-supports, are disclosed. Methods also are provided for preparing silica-coated alumina activator-supports, for preparing catalyst compositions, and for using the catalyst compositions to polymerize olefins.

First claim

We claim:

1. A catalyst composition comprising:
(a) a metallocene compound; and
(b) an activator-support comprising a silica-coated alumina treated with an electron-withdrawing anion, wherein:
the silica-coated alumina has a weight ratio of alumina to silica in a range from about 1.2:1 to about 25:1,
the electron-withdrawing anion comprises chloride, bromide, phosphate, triflate, sulfate, or any combination thereof, and
a catalyst activity of the catalyst composition comprising the activator-support is greater than that of a catalyst system containing a silica-alumina treated with the electron-withdrawing anion, under the same polymerization conditions.

2. The catalyst composition of claim 1 , wherein the amount of the metallocene compound in the catalyst composition is in a range from about 0.5 to about 150 micromoles of the metallocene compound per gram of the activator-support.

3. The catalyst composition of claim 1 , wherein:
the weight ratio of alumina to silica is in a range from about 1.5:1 to about 15:1; and
the activator-support further comprises zinc.

4. The catalyst composition of claim 1 , wherein:
the weight ratio of alumina to silica is in a range from about 1.5:1 to about 4:1;
the electron-withdrawing anion comprises phosphate; and
the catalyst composition further comprises a co-catalyst.

5. The catalyst composition of claim 1 , wherein:
a catalyst activity of the catalyst composition is greater than about 1000 grams of polyethylene per gram of activator-support per hour under slurry polymerization conditions, using isobutane as a diluent, with a polymerization temperature of 90° C. and a reactor pressure of 420 psig; and
a catalyst activity of the catalyst composition is greater than about 25,000 grams of polyethylene per gram of metallocene compound per hour under slurry polymerization conditions, using isobutane as a diluent, with a polymerization temperature of 90° C. and a reactor pressure of 420 psig.

6. The catalyst composition of claim 1 , the catalyst activity of the catalyst composition comprising the activator-support is at least twice that of the catalyst system containing the silica-alumina treated with the electron-withdrawing anion, under the same polymerization conditions.

7. The catalyst composition of claim 1 , wherein the metallocene compound comprises a bridged cyclopentadienyl-fluorenyl metallocene compound, an unbridged bis-cyclopentadienyl metallocene compound, an unbridged cyclopentadienyl-indenyl metallocene compound, or a combination thereof.

8. The catalyst composition of claim 1 , wherein the catalyst composition comprises two metallocene compounds.

9. An olefin polymerization process, the process comprising:
contacting the catalyst composition of claim 1 with an olefin monomer and optionally an olefin comonomer to produce an olefin polymer.

10. The process of claim 9 , wherein the catalyst composition in contacted with ethylene and an olefin comonomer comprising propylene, 1-butene, 1-hexene, 1-octene, or a combination thereof.

11. The process of claim 9 , wherein the olefin polymer comprises an ethylene polymer characterized by:
less than about 5 long chain branches (LCB) per million total carbon atoms; and
a CY-a parameter in a range from about 0.4 to about 0.7.

12. A catalyst composition comprising:
(a) a metallocene compound;
(b) an activator-support comprising a silica-coated alumina treated with an electron-withdrawing anion; and
(c) an organoaluminum compound comprising trimethylaluminum, triethylaluminum, tri-n-propylaluminum, tri-n-butylaluminum, triisobutylaluminum, tri-n-hexylaluminum, tri-n-octylaluminum, diisobutylaluminum hydride, diethylaluminum ethoxide, diethylaluminum chloride, or any combination thereof; wherein:
the silica-coated alumina has a weight ratio of alumina to silica in a range from about 1.2:1 to about 25:1,
the electron-withdrawing anion comprises chloride, bromide, phosphate, triflate, sulfate, or any combination thereof, and
a catalyst activity of the catalyst composition comprising the activator-support is greater than that of a catalyst system containing a silica-alumina treated with the electron-withdrawing anion, under the same polymerization conditions.

13. The catalyst composition of claim 12 , wherein the amount of the metallocene compound in the catalyst composition is in a range from about 1 to about 120 micromoles of the metallocene compound per gram of the activator-support.

14. The catalyst composition of claim 12 , wherein:
the weight ratio of alumina to silica is in a range from about 1.5:1 to about 15:1; and
the activator-support further comprises zinc.

15. The catalyst composition of claim 12 , wherein:
the catalyst activity of the catalyst composition comprising the activator-support is at least about 3 times that of the catalyst system containing the silica-alumina treated with the electron-withdrawing anion, under the same polymerization conditions; and
the weight ratio of alumina to silica is in a range from about 1.5:1 to about 4:1.

16. The catalyst composition of claim 12 , wherein:
a catalyst activity of the catalyst composition is greater than about 1000 grams of polyethylene per gram of activator-support per hour under slurry polymerization conditions, using isobutane as a diluent, with a polymerization temperature of 90° C. and a reactor pressure of 420 psig; and
a catalyst activity of the catalyst composition is greater than about 25,000 grams of polyethylene per gram of metallocene compound per hour under slurry polymerization conditions, using isobutane as a diluent, with a polymerization temperature of 90° C. and a reactor pressure of 420 psig.

17. The catalyst composition of claim 12 , wherein the metallocene compound comprises a bridged cyclopentadienyl-fluorenyl metallocene compound, an unbridged bis-cyclopentadienyl metallocene compound, an unbridged cyclopentadienyl-indenyl metallocene compound, or a combination thereof.

18. The catalyst composition of claim 12 , wherein the catalyst composition comprises two metallocene compounds.

19. An olefin polymerization process, the process comprising:
contacting the catalyst composition of claim 12 with an olefin monomer and optionally an olefin comonomer to produce an olefin polymer.

20. The process of claim 19 , wherein the catalyst composition is contacted with ethylene and an olefin comonomer comprising propylene, 1-butene, 1-hexene, 1-octene, or a combination thereof.

21. A catalyst composition comprising:
(a) a metallocene compound; and
(b) an activator-support comprising a silica-coated alumina treated with an electron-withdrawing anion, wherein:
the silica-coated alumina has a weight ratio of alumina to silica in a range from about 1:1 to about 2:1, and
the electron-withdrawing anion comprises chloride, bromide, phosphate, triflate, sulfate, or any combination thereof.

22. The catalyst composition of claim 21 , wherein:
the weight ratio of alumina to silica is in a range from about 1.2:1 to about 1.8:1; and
the catalyst composition further comprises an organoaluminum co-catalyst.

23. The catalyst composition of claim 22 , wherein a catalyst activity of the catalyst composition comprising the activator-support is at least twice than that of a catalyst system containing a silica-alumina treated with the electron-withdrawing anion, under the same polymerization conditions.

Assignees

• Chevron Phillips Chemical Co Lp

Inventors

• Mcdaniel Max P
• Yang Qing
• Muninger Randy S
• Benham Elizabeth A
• Clear Kathy S

Classifications

• C08F210/16 Primary

  Copolymers of ethene with alpha-alkenes, e.g. EP rubbers · CPC title

• B01J31/1616

  Coordination complexes, e.g. organometallic complexes, immobilised on an inorganic support, e.g. ship-in-a-bottle type catalysts (catalysts comprising molecular sieves B01J29/00) · CPC title

• B01J27/12

  Fluorides · CPC title

• B01J31/1805

  the ligands containing nitrogen · CPC title

• C08F4/65925

  two cyclopentadienyl rings being mutually non-bridged · CPC title