Production of high haze films using metallocene-based catalyst systems in cyclohexene

Patent metadata

Field	Value
Publication number	US-10131725-B2
Application number	US-201715807665-A
Country	US
Kind code	B2
Filing date	Nov 9, 2017
Priority date	Jun 26, 2015
Publication date	Nov 20, 2018
Grant date	Nov 20, 2018

Abstract

Methods for preparing metallocene-based catalyst systems containing an activator-support are disclosed. These methods are directed to contacting an activator-support, an organoaluminum compound, and a mixture containing a metallocene compound and cyclohexene or a mixture of cyclohexane and 1-hexene, resulting in catalyst systems with increased catalytic activity for the polymerization of olefins. The olefin polymers can be used to produce film products with high haze values.

First claim

We claim:

1. A method of making an ethylene polymer capable of producing a film with high haze, the method comprising:
contacting a catalyst composition with ethylene and an olefin comonomer in a polymerization reactor system under polymerization conditions to produce an ethylene polymer, wherein:
the catalyst composition comprises:
(A) an activator-support;
(B) an organoaluminum compound:
(C) a metallocene compound; and
(D) cyclohexene; and

the film has a haze in a range from about 8% to about 30%.

2. The method of claim 1 , wherein the ethylene polymer has:
a density in a range from about 0.90 to about 0.93 g/cm 3 ;
a melt index in a range from about 0.5 to about 3 g/10 min; and
a ratio of Mw/Mn in a range from about 2 to about 4.

3. The method of claim 1 , wherein:
the film has an average thickness from about 0.5 to about 8 mils; and
the film is a blown film.

4. The method of claim 1 , wherein:
the polymerization reactor system comprises a slurry reactor, a gas-phase reactor, a solution reactor, or a combination thereof; and
the olefin comonomer comprises 1-butene, 1-hexene, 1-octene, or a mixture thereof.

5. The method of claim 4 , wherein the catalyst composition further comprises 1-hexene.

6. The method of claim 5 , wherein:
the activator-support comprises a fluorided solid oxide, a sulfated solid oxide, a phosphated solid oxide, or a combination thereof; and
the organoaluminum compound comprises trimethylaluminum, triethylaluminum, tri-n-propylaluminum, tri-n-butylaluminum, triisobutylaluminum, or any combination thereof.

7. The method of claim 6 , wherein the metallocene compound comprises an unbridged zirconium or hafnium based metallocene compound containing two cyclopentadienyl groups, two indenyl groups, or a cyclopentadienyl and an indenyl group.

8. The method of claim 6 , wherein the metallocene compound comprises a bridged zirconium or hafnium based metallocene compound with a cyclopentadienyl group and a fluorenyl group.

9. A polymerization process comprising:
contacting a catalyst composition with ethylene and an α-olefin comonomer in a polymerization reactor system under polymerization conditions to produce an ethylene polymer, wherein:
the catalyst composition comprises:
(A) an activator-support;
(B) an organoaluminum compound:
(C) a metallocene compound; and
(D) cyclohexene; and

a film comprising the ethylene polymer is characterized by a haze in a range from about 8% to about 30%.

10. The process of claim 9 , wherein the ethylene polymer contains substantially no residual toluene.

11. The process of claim 9 , wherein:
the film has an average thickness from about 0.8 to about 5 mils;
the haze is in a range from about 9% to about 25%; and
the film is a blown film.

12. The process of claim 11 , wherein:
the ethylene polymer has a density in a range from about 0.91 to about 0.93 g/cm 3 and a melt index of less than or equal to about 3 g/10 min; and
the ethylene polymer comprises an ethylene/1-butene copolymer, an ethylene/1-hexene copolymer, and/or an ethylene/1-octene copolymer.

13. The process of claim 12 , wherein the catalyst composition further comprises 1-hexene at a weight ratio of 1-hexene:cyclohexene in the catalyst composition in a range from about 90:10 to about 50:50.

14. The process of claim 13 , wherein:
the activator-support comprises fluorided alumina, fluorided silica-alumina, fluorided silica-zirconia, fluorided silica-coated alumina, fluorided-chlorided silica-coated alumina, sulfated alumina, sulfated silica-alumina, sulfated silica-coated alumina, or any combination thereof; and
the metallocene compound comprises a bridged zirconium or hafnium based metallocene compound with a cyclopentadienyl group and a fluorenyl group.

15. A method of making a film with high haze, the method comprising:
(a) contacting a catalyst composition with ethylene and an olefin comonomer in a polymerization reactor system under polymerization conditions to produce an ethylene polymer, wherein the catalyst composition comprises:
(A) an activator-support;
(B) an organoaluminum compound:
(C) a metallocene compound; and
(D) cyclohexene; and

(b) melt processing the ethylene polymer through a film die to form the film, wherein the film has a haze in a range from about 8% to about 30%.

16. The method of claim 15 , wherein:
the activator-support comprises a fluorided solid oxide, a sulfated solid oxide, a phosphated solid oxide, or a combination thereof;
the olefin comonomer comprises a C 3 -C 10 alpha-olefin; and
the polymerization reactor system comprises a slurry reactor, a gas-phase reactor, a solution reactor, or a combination thereof.

17. The method of claim 16 , wherein the catalyst composition further comprises 1-hexene.

18. The method of claim 16 , wherein the ethylene polymer has:
a density in a range from about 0.90 to about 0.925 g/cm 3 ; and
a melt index in a range from about 0.7 to about 2 g/10 min.

19. The method of claim 18 , wherein:
the film has an average thickness from about 0.5 to about 8 mils;
the haze is in a range from about 9% to about 25%; and
the film is a blown film.

20. The method of claim 19 , wherein:
the catalyst composition further comprises 1-hexene at a weight ratio of 1-hexene:cyclohexene in the catalyst composition in a range from about 90:10 to about 50:50; and
the activator-support comprises fluorided alumina, fluorided silica-alumina, fluorided silica-zirconia, fluorided silica-coated alumina, fluorided-chlorided silica-coated alumina, sulfated alumina, sulfated silica-alumina, sulfated silica-coated alumina, phosphated alumina, or a combination thereof.

Assignees

• Chevron Phillips Chemical Co Lp

Inventors

• Clark Kensha Marie
• Yang Qing
• Glass Gary L

Classifications

• C08F2/06

  Organic solvent · CPC title

• C08F4/649

  organic · CPC title

• C08F4/65927

  two cyclopentadienyl rings being mutually bridged · CPC title

• C08F4/65925

  two cyclopentadienyl rings being mutually non-bridged · CPC title

• C08F4/6592

  containing at least one cyclopentadienyl ring, condensed or not, e.g. an indenyl or a fluorenyl ring · CPC title