Metallocene catalyst systems with chemically-treated solid oxides for producing ethylene-based plastomers and elastomers

Patent metadata

Field	Value
Publication number	US-11326003-B2
Application number	US-202117480240-A
Country	US
Kind code	B2
Filing date	Sep 21, 2021
Priority date	Jul 14, 2020
Publication date	May 10, 2022
Grant date	May 10, 2022

Abstract

Polymerization processes for producing ethylene-based plastomers and elastomers having densities less than 0.91 g/cm3 utilize a metallocene-based catalyst system containing a chemically-treated solid oxide. These polymerization processes can be conducted in a slurry reactor, a solution reactor, and/or a gas phase reactor. Ethylene polymers produced from the polymerization process can be characterized by a density of less than 0.91 g/cm3, a CY-a parameter of less than 0.2, and a ratio of HLMI/MI of at least 30, or a density less than 0.91 g/cm3, a CY-a parameter from 0.25 to 0.75, and a ratio of Mw/Mn from 2 to 3.

First claim

We claim:

1. A gas phase polymerization process for producing an ethylene polymer having a density of less than or equal to about 0.91 g/cm 3 , the process comprising:
contacting a catalyst composition with ethylene and an α-olefin comonomer in a gas phase reactor containing an inert gas and a C 4 -C 8 alkane at a polymerization temperature in a range from about 48° C. to about 82° C. to produce the ethylene polymer;
wherein the catalyst composition comprises a metallocene compound, a chemically-treated solid oxide, and optionally, a co-catalyst; and
wherein a ratio of heavy hydrocarbon partial pressure to vapor pressure (ratio of P/P*) in the gas phase reactor is less than or equal to about 0.95.

2. The process of claim 1 , wherein:
the density is in a range from about 0.865 to about 0.905 g/cm 3 ;
the α-olefin comonomer comprises 1-butene and/or 1-hexene;
the chemically-treated solid oxide comprises a fluorided solid oxide and/or a sulfated solid oxide; and
the catalyst composition comprises an organoaluminum co-catalyst.

3. The process of claim 1 , wherein:
the chemically-treated solid oxide has an average particle size in a range from about 40 to about 150 μm; and
an amount of transition metal of the metallocene compound based on the weight of the chemically-treated solid oxide is in a range from about 50 to about 5000 ppm.

4. The process of claim 1 , wherein:
the polymerization temperature is in a range from about 48 to about 70° C.; and
the ratio of P/P* is less than or equal to about 0.9.

5. The process of claim 1 , wherein:
the gas phase reactor is a fluidized bed gas-phase reactor;
the inert gas comprises nitrogen, ethane, propane, or a combination thereof;
the C 4 -C 8 alkane comprises butane, pentane, hexane, or a combination thereof, and a C 4 -C 8 alkane concentration in the gas phase reactor is in a range from about 10 to about 30 vol %; and
a carrier for the catalyst composition into the fluidized bed gas-phase reactor is a hydrocarbon.

6. The process of claim 1 , wherein the chemically-treated solid oxide comprises fluorided alumina, chlorided alumina, bromided alumina, sulfated alumina, fluorided silica-alumina, chlorided silica-alumina, bromided silica-alumina, sulfated silica-alumina, fluorided silica-zirconia, chlorided silica-zirconia, bromided silica-zirconia, sulfated silica-zirconia, fluorided silica-titania, fluorided silica-coated alumina, fluorided-chlorided silica-coated alumina, sulfated silica-coated alumina, phosphated silica-coated alumina, or any combination thereof.

7. The process of claim 6 , wherein the catalyst composition comprises the co-catalyst.

8. The process of claim 6 , wherein the density is in a range from about 0.865 to about 0.905 g/cm 3 .

9. The process of claim 8 , wherein an amount of transition metal of the metallocene compound based on the weight of the chemically-treated solid oxide is in a range from about 50 to about 5000 ppm.

10. The process of claim 1 , wherein the gas phase reactor is a fluidized bed gas-phase reactor.

11. The process of claim 10 , wherein a C 4 -C 8 alkane concentration in the gas phase reactor is in a range from about 10 to about 30 vol %.

12. The process of claim 10 , wherein the ratio of P/P* is less than or equal to about 0.85.

13. The process of claim 10 , wherein the polymerization temperature is in a range from about 48 to about 70° C.

14. The process of claim 10 , wherein an amount of transition metal of the metallocene compound based on the weight of the chemically-treated solid oxide is in a range from about 100 to about 2000 ppm.

15. The process of claim 10 , wherein:
the density is in a range from about 0.865 to about 0.905 g/cm 3 ; and
the α-olefin comonomer comprises 1-butene and/or 1-hexene.

16. The process of claim 15 , wherein the chemically-treated solid oxide comprises a fluorided solid oxide and/or a sulfated solid oxide.

17. The process of claim 16 , wherein the metallocene compound is a single atom bridged or two atom bridged metallocene compound.

18. The process of claim 10 , wherein:
the ethylene polymer comprises an ethylene/1-butene copolymer, an ethylene/1-hexene copolymer, and/or an ethylene/1-octene copolymer; and
the ethylene polymer has from about 20 to about 60 SCBs per 1000 total carbon atoms.

19. The process of claim 18 , wherein:
the inert gas comprises nitrogen, ethane, propane, or a combination thereof; and
the C 4 -C 8 alkane comprises butane, pentane, hexane, or a combination thereof.

Assignees

• Chevron Phillips Chemical Co Lp

Inventors

• Kufeld Scott E
• Mcdaniel Max P
• Dooley Kenneth A

Classifications

• C08F210/16 Primary

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

• C08F210/02 Primary

  Ethene · CPC title

• C08F2500/16

  Syndiotactic · CPC title

• C08F4/65927

  two cyclopentadienyl rings being mutually bridged · CPC title

• C08F2500/08

  Low density, i.e. < 0.91 g/cm3 · CPC title