Processes for preparing metallocene-based catalyst systems for the control of long chain branch content

Patent metadata

Field	Value
Publication number	US-12240933-B2
Application number	US-202418585446-A
Country	US
Kind code	B2
Filing date	Feb 23, 2024
Priority date	Aug 26, 2021
Publication date	Mar 4, 2025
Grant date	Mar 4, 2025

Abstract

Methods for preparing a metallocene-based catalyst composition that can impact the long chain branching of ethylene homopolymers and copolymers produced using the catalyst composition are described. The catalyst composition can be prepared by contacting a metallocene compound, a hydrocarbon solvent, and a first organoaluminum compound for a first period of time to form a metallocene solution, and then contacting the metallocene solution with an activator-support and a second organoaluminum compound for a second period of time to form the catalyst composition.

First claim

We claim:

1. A process to produce a catalyst composition, the process comprising:
(a) contacting a metallocene compound, a hydrocarbon solvent, and a first organoaluminum compound for a first period of time to form a metallocene solution; and
(b) contacting the metallocene solution with an activator-support and a second organoaluminum compound for a second period of time to form the catalyst composition,
wherein:
the first organoaluminum compound comprises triisobutylaluminum and/or tri-n-octylaluminum;
the second organoaluminum compound comprises 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; and
the first organoaluminum compound and the second organoaluminum compound are different.

2. The process of claim 1 , wherein the activator-support comprises fluorided silica-alumina, fluorided silica-coated alumina, sulfated alumina, or any combination thereof.

3. The process of claim 1 , wherein the catalyst composition is substantially free of aluminoxane compounds, organoboron or organoborate compounds, ionizing ionic compounds, or combinations thereof.

4. The process of claim 1 , wherein:
a weight ratio of the metallocene compound to the activator-support is from 1:1 to 1:100,000; and
a molar ratio of the first organoaluminum compound to the second organoaluminum compound is from 1000:1 to 1:1000.

5. A polymerization process comprising:
(I) performing the process of claim 1 ; and
(II) contacting the catalyst composition with ethylene and an optional olefin comonomer in a polymerization reactor system under polymerization conditions to produce an ethylene polymer.

6. The polymerization process of claim 5 , wherein
the catalyst composition is contacted with ethylene and an olefin comonomer comprising a C 3 -C 10 alpha-olefin; and
a LCB content of the ethylene polymer produced by the process is at least 50% greater than a LCB content of an ethylene polymer produced under the same polymerization conditions using a catalyst system obtained without the first organoaluminum compound.

7. The process of claim 1 , wherein step (a) comprises contacting a solution of the metallocene compound in the hydrocarbon solvent with the first organoaluminum compound.

8. The process of claim 1 , wherein the activator-support comprises a fluorided solid oxide and/or a sulfated solid oxide.

9. The process of claim 8 , wherein the metallocene compound comprises a single bridged metallocene compound or a single unbridged metallocene compound.

10. The process of claim 1 , wherein the metallocene compound comprises:
a bridged zirconium or hafnium based metallocene compound with a cyclopentadienyl group and a fluorenyl group; and/or
a bridged zirconium based metallocene compound with two indenyl groups.

11. The process of claim 1 , wherein the hydrocarbon solvent comprises an alkane, an olefin, an aromatic, or any combination thereof.

12. The process of claim 1 , wherein:
the activator-support comprises fluorided silica-alumina, fluorided silica-coated alumina, sulfated alumina, or any combination thereof; and
the hydrocarbon solvent comprises 1-hexene and/or heptane.

13. The process of claim 1 , wherein:
a molar ratio of the first organoaluminum compound to the metallocene compound is from 1:1 to 1000:1; and
a weight ratio of the activator-support to the second organoaluminum compound is from 100:1 to 1:100.

14. The process of claim 1 , wherein the activator-support comprises a solid oxide treated with an electron-withdrawing anion.

15. The process of claim 14 , wherein the activator-support contains from 1 to 30 wt % of the electron-withdrawing anion.

16. The process of claim 15 , wherein:
the solid oxide comprises silica, alumina, silica-alumina, silica-coated alumina, aluminum phosphate, aluminophosphate, heteropolytungstate, titania, zirconia, magnesia, boria, zinc oxide, or any combination thereof; and
the electron-withdrawing anion comprises sulfate, bisulfate, fluoride, chloride, bromide, iodide, fluorosulfate, fluoroborate, phosphate, fluorophosphate, trifluoroacetate, triflate, fluorozirconate, fluorotitanate, phospho-tungstate, tungstate, molybdate, or any combination thereof.

17. The process of claim 1 , wherein:
the first period of time is from 5 sec to 48 hours; and
the second period of time is from 1 sec to 48 hours.

18. The polymerization process of claim 5 , wherein the ethylene polymer comprises an ethylene homopolymer, an ethylene/1-butene copolymer, an ethylene/1-hexene copolymer, an ethylene/1-octene copolymer, or any combination thereof.

19. A process to produce a catalyst composition, the process comprising:
(a) contacting a metallocene compound, a hydrocarbon solvent, and a first organoaluminum compound for a first period of time to form a metallocene solution; and
(b) contacting the metallocene solution with an activator-support and a second organoaluminum compound for a second period of time to form the catalyst composition,
wherein:
the metallocene compound comprises rac-ethylene-bis(indenyl) zirconium dichloride;
the hydrocarbon solvent comprises an olefin solvent and/or an alkane solvent; and
the first organoaluminum compound comprises triisobutylaluminum.

20. A process to produce a catalyst composition, the process comprising:
(a) contacting a metallocene compound, a hydrocarbon solvent, and a first organoaluminum compound for a first period of time to form a metallocene solution; and
(b) contacting the metallocene solution with an activator-support and a second organoaluminum compound for a second period of time to form the catalyst composition,
wherein:
the metallocene compound comprises rac-ethylene-bis(indenyl) zirconium dichloride;
the hydrocarbon solvent comprises an aromatic solvent and/or an alkane solvent; and
the first organoaluminum compound comprises trioctylaluminum.

21. A process to produce a catalyst composition, the process comprising:
(a) contacting a metallocene compound, a hydrocarbon solvent, and a first organoaluminum compound for a first period of time to form a metallocene solution; and
(b) contacting the metallocene solution with an activator-support and a second organoaluminum compound for a second period of time to form the catalyst composition,
wherein:
the metallocene compound comprises methyl(buten-3-yl)methylidene(η5-cyclopentadienyl)(η5-2,7-di-tert-butylfluoren-9-ylidene) zirconium dichloride;
the hydrocarbon solvent comprises an aromatic solvent; and
the first organoaluminum compound comprises triisobutylaluminum.

Assignees

• Chevron Phillips Chemical Co Lp

Inventors

• Yang Qing
• Mcdaniel Max P
• Crain Tony R

Classifications

• C08F210/16

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

• C08F2500/09

  Long chain branches · CPC title

• C08F4/64

  Titanium, zirconium, hafnium or compounds thereof · CPC title

• C08F4/52

  selected from boron, aluminium, gallium, indium, thallium or rare earths (C08F4/14 takes precedence) · CPC title

• C08F110/02

  Ethene · CPC title