Mixed catalyst system with four metallocenes on a single support

文档序号：1277037 发布日期：2020-08-25 浏览：23次中文

阅读说明：本技术 具有在单一载体上的四种茂金属的混合的催化剂体系 (Mixed catalyst system with four metallocenes on a single support ) 是由 M·W·赫尔特卡普 D·F·森德斯 M·S·贝多雅吕清泰于 2018-09-20 设计创作，主要内容包括：本发明提供了负载的催化剂体系及其使用方法。具体地,所述催化剂体系包括四种不同的催化剂,载体材料和活化剂。所述催化剂体系可以用于制备聚烯烃例如聚乙烯。(The present invention provides supported catalyst systems and methods of use thereof. Specifically, the catalyst system includes four different catalysts, a support material, and an activator. The catalyst system can be used to prepare polyolefins such as polyethylene.)

1. A catalyst system comprising:

at least two different catalysts represented by formula (A):

wherein:

m is Hf or Zr;

each R¹、R²And R⁴Independently is hydrogen, alkoxy or C₁-C₄₀A substituted or unsubstituted hydrocarbyl group;

R³independently is hydrogen, alkoxy or C₁-C₄₀Substituted or unsubstituted hydrocarbyl or is-CH₂-SiR'₃or-CH₂-CR'₃And each R' is independently C₁-C₂₀A substituted or unsubstituted hydrocarbon group;

each R⁷、R⁸、R⁹And R¹⁰Independently of one another is hydrogen, alkoxy, C₁-C₄₀Substituted or unsubstituted hydrocarbyl, -CH₂-SiR'₃or-CH₂-CR'₃Wherein each R' is independently C₁-C₂₀A substituted or unsubstituted hydrocarbyl group, provided that R⁷、R⁸、R⁹And R¹⁰is-CH₂-SiR'₃or-CH₂-CR'₃Preferably R⁸And/or R⁹is-CH₂-SiR'₃or-CH₂-CR'₃(ii) a Preferably R⁹is-CH₂-SiR'₃or-CH₂-CR'₃；

T¹Is a bridging group; and

each X is independently a monovalent anionic ligand, or two xs are joined and bound to a metal atom to form a metallocyclic ring, or two xs are joined to form a chelating ligand, a diene ligand, or an alkylidene ligand;

at least two different catalysts represented by formula (B):

T² _yCp_mM¹X_q(B)

wherein:

each Cp is independently a cyclopentadienyl, indenyl, or fluorenyl, which may be independently substituted or unsubstituted;

M¹is zirconium or hafnium;

T²is a bridging group;

y is 0 or 1, which indicates the absence or presence of T;

x is halo, hydrogen, alkyl, alkenyl, or arylalkyl;

m is 2 or 3, q is 0, 1, 2 or 3, and the sum of m + q is equal to the oxidation state of the transition metal, 2, 3 or 4;

each Cp and X is bound to M¹The above step (1);

a carrier material; and

an activator.

2. A catalyst system comprising:

at least two different catalysts represented by formula (A):

wherein:

m is Hf or Zr;

each R¹、R²And R⁴Independently is hydrogen, alkoxy or C₁-C₄₀A substituted or unsubstituted hydrocarbyl group;

T¹Is a bridging group; and

at least one catalyst represented by formula (C) and at least one catalyst represented by formula (D):

Cp_mM¹X_q(C)

T³Cp_mM²X_q(D)

wherein:

each Cp is independently a cyclopentadienyl, indenyl, or fluorenyl, which may be independently substituted or unsubstituted;

M¹is zirconium or hafnium;

M²is zirconium or hafnium;

T³is a bridging group;

x is halo, hydrogen, alkyl, alkenyl, or arylalkyl;

m is 2 or 3, q is 0, 1, 2 or 3, and the sum of m + q is equal to the oxidation state of the transition metal, 2, 3 or 4;

each Cp and X is bound to M¹Or M²The above step (1);

a carrier material; and

an activator.

3. The catalyst system of claim 1 wherein M is Hf or Zr, each R¹、R²、R³And R⁴Is H or C₁-C₂₀Alkyl, and R⁹is-R²⁰-SiR'₃or-R²⁰-CR'₃Wherein R is²⁰Is CH₂And R' is C₁-C₂₀Alkyl or aryl.

4. The catalyst system of claim 2, wherein M¹And M²Both are zirconium.

5. The catalyst system of claim 2, wherein M¹And M²Both are zirconium andwherein T is³Is a bridging group containing at least 2 or more carbon, silicon, oxygen, nitrogen atoms, preferably T³Is Si (Me)₂OSi(Me)₂-、-Si(Me)₂Si(Me)₂-or-CH₂CH₂-。

6. The catalyst system of claim 2, wherein M¹And M²Both zirconium and M is hafnium.

7. The catalyst system of claim 1 or 2 wherein M is Hf or Zr, each R¹、R²、R³And R⁴Is hydrogen or C₁-C₂₀Alkyl, and R⁹is-R²⁰-SiR'₃or-R²⁰-CR'₃Wherein R is²⁰Is CH₂And R' is C₁-C₂₀Alkyl or aryl, and R³is-R²⁰-SiR'₃or-R₂₀-CR'₃Wherein R is₂₀Is CH₂And R' is C₁-C₂₀Alkyl or aryl.

8. The catalyst system of any one of claims 1 to 7, wherein M in formula B¹Is Zr, and Cp is indenyl.

9. The catalyst system of claim 1, 2, 4, 5, 6, or 8, wherein each of the catalysts represented by formula (a) is selected from the group consisting of:

rac/meso-Me₂Si(3-Me₃Si-CH₂-Cp)₂HfMe₂(ii) a racemic-Me₂Si(3-Me₃Si-CH₂-Cp)₂HfMe₂(ii) a rac/meso-Ph₂Si(3-Me₃Si-CH₂-Cp)₂HfMe₂(ii) a rac/meso-PhMeSi (3-Me)₃Si-CH₂-Cp)₂HfMe₂(ii) a Rac/meso- (CH)₂)₄Si(3-Me₃Si-CH₂-Cp)₂HfMe₂(ii) a Rac/meso- (CH)₂)₃Si(3-Me₃Si-CH₂-Cp)₂HfMe₂；Me(H)Si(3-Me₃Si-CH₂-Cp)₂HfMe₂；Ph(H)Si(3-Me₃Si-CH₂-Cp)₂HfMe₂(ii) a Rac/meso- (biphenyl)₂Si(3-Me₃Si-CH₂-Cp)₂HfMe₂(ii) a Rac/meso- (F-C)₆H₄)₂Si(3-Me₃Si-CH₂-Cp)₂HfMe₂(ii) a rac/meso-Me₂Ge(3-Me₃Si-CH₂-Cp)₂HfMe₂(ii) a racemic-Me₂Ge(3-Me₃Si-CH₂-Cp)₂HfMe₂(ii) a rac/meso-Ph₂Ge(3-Me₃Si-CH₂-Cp)₂HfMe₂；Me₂Si(Me₄Cp)(3-Me₃Si-CH₂-Cp)HfMe₂；Ph₂Si(Me₄Cp)(3-Me₃Si-CH₂-Cp)HfMe₂；Me₂Ge(Me₄Cp)(3-Me₃Si-CH₂-Cp)HfMe₂；Ph₂Ge(Me₄Cp)(3-Me₃Si-CH₂-Cp)HfMe₂；PhMeSi(Me₄Cp)(3-Me₃Si-CH₂-Cp)HfMe₂；(CH₂)₃Si(Me₄Cp)(3-Me₃Si-CH₂-Cp)HfMe₂；(CH₂)₄Si(Me₄Cp)(3-Me₃Si-CH₂-Cp)HfMe₂；Et₂Si(Me₄Cp)(3-Me₃Si-CH₂-Cp)HfMe₂(ii) a And forms thereof, wherein Me₂Is made from Et₂、Cl₂、Br₂、I₂Or Ph₂And (3) substituted.

10. The catalyst system of any one of claims 1-9, wherein each of the catalysts represented by formula (B) is selected from the group consisting of:

bis (cyclopentadienyl) zirconium dichloride, bis (cyclopentadienyl) zirconium dimethyl, bis (n-butylcyclopentadienyl) zirconium dichloride, bis (n-butylcyclopentadienyl) zirconium dimethyl, bis (cyclopentadienyl) zirconium dimethyl, bis (n-butylcyclopentadienyl) zirconium dimethyl, bisPentamethylcyclopentadienyl) zirconium dichloride, bis (pentamethylcyclopentadienyl) zirconium dimethyl, bis (pentamethylcyclopentadienyl) hafnium dichloride, bis (pentamethylcyclopentadienyl) zirconium dimethyl, bis (1-methyl-3-n-butylcyclopentadienyl) zirconium dichloride, bis (1-methyl-3-n-butylcyclopentadienyl) zirconium dimethyl, bis (1-methyl-3-phenylcyclopentadienyl) zirconium dichloride, bis (1-methyl-3-phenylcyclopentadienyl) zirconium dimethyl, bis (1-methyl-3-n-butylcyclopentadienyl) hafnium dichloride, bis (1-methyl-3-n-butylcyclopentadienyl) zirconium dimethyl, bis (indenyl) zirconium dichloride, bis (indenyl) zirconium dimethyl, bis (tetrahydro-1-indenyl) zirconium dichloride, bis (tetrahydro-1-indenyl) zirconium dimethyl, (n-propylcyclopentadienyl) (pentamethylcyclopentadienyl) zirconium dichloride, (n-propylcyclopentadienyl) (pentamethylcyclopentadienyl) zirconium dimethyl, rac/meso-bis (1-ethylindenyl) zirconium dichloride, rac/meso-bis (1-ethylindenyl) zirconium dimethyl, rac/meso-bis (1-methylindenyl) zirconium dichloride, rac/meso-bis (1-methylindenyl) zirconium dimethyl, rac/meso-bis (1-propylindenyl) zirconium dichloride, rac/meso-bis (1-propylindenyl) zirconium dimethyl, rac/meso-bis (1-butylindenyl) zirconium dichloride, rac/meso-bis (1-butylindenyl) zirconium dimethyl, meso-bis (1-ethylindenyl) zirconium dichloride, meso-bis (1-ethylindenyl) zirconium dimethyl, (1-methylindenyl) (pentamethylcyclopentadienyl) zirconium dichloride, and (1-methylindenyl) (pentamethylcyclopentadienyl) zirconium dimethyl, and dimethylsilyl-bis (indenyl) zirconium dichloride, rac/meso- (Me)₂Si)₂O(Ind)₂ZrCl₂(ii) a Meso- (Me)₂Si)₂O(Ind)₂ZrCl₂(ii) a Rac/meso- (Ph)₂Si)₂O(Ind)₂ZrCl₂(ii) a Rac/meso- (MePhSi)₂O(Ind)₂ZrCl₂(ii) a Rac/meso- (tBu)₂Si-O-SiPh₂)O(Ind)₂ZrCl₂(ii) a Rac/meso- (Me)₂Si)₂O(1-MeInd)₂ZrCl₂(ii) a Rac/meso- (Ph)₂Si)₂O(1-MeInd)₂ZrCl₂(ii) a Outer coverRac/meso- (MePhSi)₂O(1-MeInd)₂ZrCl₂(ii) a Rac/meso- (tBu)₂Si-O-SiPh₂)O(1-MeInd)₂ZrCl₂(ii) a Rac/meso- (Me)₂Si)₂O(1-EtInd)₂ZrCl₂(ii) a Rac/meso- (Ph)₂Si)₂O(1-EtInd)₂ZrCl₂(ii) a Rac/meso- (MePhSi)₂O(1-EtInd)₂ZrCl₂(ii) a Rac/meso- (tBu)₂Si-O-SiPh₂)O(1-EtInd)₂ZrCl₂(ii) a Rac/meso- (Me)₂Si)₂O(1-PrInd)₂ZrCl₂(ii) a Rac/meso- (Ph)₂Si)₂O(1-PrInd)₂ZrCl₂(ii) a Rac/meso- (MePhSi)₂O(1-PrInd)₂ZrCl₂(ii) a Rac/meso- (tBu)₂Si-O-SiPh₂)O(1-PrInd)₂ZrCl₂(ii) a Rac/meso- (Me)₂Si)₂(Ind)₂ZrCl₂(ii) a Rac/meso- (Ph)₂Si)₂(Ind)₂ZrCl₂(ii) a Rac/meso- (MePhSi)₂(Ind)₂ZrCl₂(ii) a Rac/meso- (tBuPhSi)₂(Ind)₂ZrCl₂(ii) a Rac/meso- (NpPhSi)₂(Ind)₂ZrCl₂(ii) a Rac/meso- (Me)₂Si)₂(1-MeInd)₂ZrCl₂(ii) a Rac/meso- (Ph)₂Si)₂(1-MeInd)₂ZrCl₂(ii) a Rac/meso- (MePhSi)₂(1-MeInd)₂ZrCl₂(ii) a Rac/meso- (tBuPhSi)₂(1-MeInd)₂ZrCl₂(ii) a And rac/meso- (NpPhSi)₂(1-MeInd)₂ZrCl₂。

11. The catalyst system of any one of claims 2-9, wherein each of the catalysts represented by formula (C) is selected from the group consisting of:

12. The catalyst system of any one of claims 2-9 or 11, wherein each of the catalysts represented by formula (D) is selected from the group consisting of: rac/meso- (Me)₂Si)₂O(Ind)₂ZrCl₂(ii) a Meso- (Me)₂Si)₂O(Ind)₂ZrCl₂(ii) a Rac/meso- (Ph)₂Si)₂O(Ind)₂ZrCl₂(ii) a Rac/meso- (MePhSi)₂O(Ind)₂ZrCl₂(ii) a Rac/meso- (tBu)₂Si-O-SiPh₂)O(Ind)₂ZrCl₂(ii) a Rac/meso- (Me)₂Si)₂O(1-MeInd)₂ZrCl₂(ii) a Rac/meso- (Ph)₂Si)₂O(1-MeInd)₂ZrCl₂(ii) a Rac/meso- (MePhSi)₂O(1-MeInd)₂ZrCl₂(ii) a Rac/meso- (tBu)₂Si-O-SiPh₂)O(1-MeInd)₂ZrCl₂(ii) a Rac/meso- (Me)₂Si)₂O(1-EtInd)₂ZrCl₂(ii) a Rac/meso- (Ph)₂Si)₂O(1-EtInd)₂ZrCl₂(ii) a Rac/meso- (MePhSi)₂O(1-EtInd)₂ZrCl₂(ii) a Rac/meso- (tBu)₂Si-O-SiPh₂)O(1-EtInd)₂ZrCl₂(ii) a Rac/meso- (Me)₂Si)₂O(1-PrInd)₂ZrCl₂(ii) a Rac/meso- (Ph)₂Si)₂O(1-PrInd)₂ZrCl₂(ii) a Rac/meso- (MePhSi)₂O(1-PrInd)₂ZrCl₂(ii) a Rac/meso- (tBu)₂Si-O-SiPh₂)O(1-PrInd)₂ZrCl₂(ii) a Rac/meso- (Me)₂Si)₂(Ind)₂ZrCl₂(ii) a Rac/meso- (Ph)₂Si)₂(Ind)₂ZrCl₂(ii) a Rac/meso- (MePhSi)₂(Ind)₂ZrCl₂(ii) a Rac/meso- (tBuPhSi)₂(Ind)₂ZrCl₂(ii) a Rac/meso- (NpPhSi)₂(Ind)₂ZrCl₂(ii) a Rac/meso- (Me)₂Si)₂(1-MeInd)₂ZrCl₂(ii) a Rac/meso- (Ph)₂Si)₂(1-MeInd)₂ZrCl₂(ii) a Rac/meso- (MePhSi)₂(1-MeInd)₂ZrCl₂(ii) a Rac/meso- (tBuPhSi)₂(1-MeInd)₂ZrCl₂(ii) a And rac/meso- (NpPhSi)₂(1-MeInd)₂ZrCl₂。

13. The catalyst system of any one of claims 1-12, wherein the support material has a surface area of 10m²/g-700m²A particle size of 10 μm to 500 μm.

14. The catalyst system of any one of claims 1-13, wherein the support material is selected from the group consisting of silica, alumina, silica-alumina, and combinations thereof.

15. The catalyst system of any one of claims 1-14, wherein the support material is fluorinated or sulfated.

16. The catalyst system of claim 15, wherein the support material has a fluorine concentration of 0.6 wt% to 3.5 wt% based on the weight of the support material.

17. The catalyst system of any one of claims 1-16, wherein the activator comprises an alumoxane or a non-coordinating anion.

18. The catalyst system of any one of claims 1-17, wherein the activator is methylalumoxane.

19. The catalyst system of any one of claims 1-18, wherein the support is a silica aluminate and comprises an electron-withdrawing anion such as fluoride or sulfate.

20. The catalyst system of any one of claims 1-19, wherein the support is treated with an aluminum alkyl.

21. The catalyst system of claim 19 or 20, wherein the support is substantially free of methylaluminoxane and/or a non-coordinating anion.

22. The catalyst system of any one of claims 1-21, wherein the catalyst represented by formula (B) is present in the catalyst system as at least two isomers.

23. The catalyst system of any one of claims 1-22, wherein the activator comprises one or more of the following: n, N-dimethylanilinium tetrakis (perfluoronaphthyl) borate, N-dimethylanilinium tetrakis (perfluorobiphenyl) borate, N-dimethylanilinium tetrakis (perfluorophenyl) borate, N-dimethylanilinium tetrakis (3, 5-bis (trifluoromethyl) phenyl) borate, triphenylcarbenium tetrakis (perfluoronaphthyl) borate, triphenylcarbenium tetrakis (perfluorobiphenyl) borate, triphenylcarbenium tetrakis (3, 5-bis (trifluoromethyl) phenyl) borate, triphenylcarbenium tetrakis (perfluorophenyl) borate, [ Me₃NH⁺][B(C₆F₅)^4-]1- (4- (tris (pentafluorophenyl) borate) -2, 3, 5, 6-tetrafluorophenyl) pyrrolidinium, [ Me ]₃NH⁺][B(C₆F₅)^4-]1- (4- (tris (pentafluorophenyl) borate) -2, 3, 5, 6-tetrafluorophenyl) pyrrolidinium, sodium tetrakis (pentafluorophenyl) borate, potassium tetrakis (pentafluorophenyl) borate, 4- (tris (pentafluorophenyl) borate) -2, 3, 5, 6-tetrafluoropyridinium, sodium tetrakis (perfluorophenyl) aluminate, potassium tetrakis (pentafluorophenyl) borate, and N, N-dimethylanilinium tetrakis (perfluorophenyl) aluminate.

24. A process for polymerizing olefin monomers comprising contacting one or more olefin monomers with the catalyst system of any of claims 1-23.

25. The process of claim 24, wherein the olefin monomer comprises ethylene and the olefin monomer polymerizes to form linear low density polyethylene.

26. A process for producing an ethylene alpha-olefin copolymer comprising: polymerizing ethylene and at least one alpha-olefin by contacting the ethylene and the at least one alpha-olefin with the catalyst system of any of claims 1-23 in at least one gas phase reactor at a reactor pressure of 0.7 to 70bar and a reactor temperature of 20 ℃ to 150 ℃ to form an ethylene alpha-olefin copolymer.

27. An ethylene alpha-olefin copolymer obtained by contacting ethylene, at least one alpha-olefin, and the catalyst system of any of claims 1-23 in at least one gas phase reactor, the copolymer having a density of 0.890g/cc or greater, a melt flow index of 0.1 to 80g/10min, and a Mw/Mn of 2.5 to 12.5.

28. The copolymer of claim 27, wherein the copolymer has a density of 0.900 to 0.940 g/cc.

29. The copolymer of claim 27 or 28, wherein the Mz/Mw of the copolymer is from 2 to 3.

30. The copolymer of any of claims 27, 28 or 29 wherein the copolymer has a Mw value of 50000 and 250000g/mol and a Mw/Mn value of 2.5 to 10.

31. A process for producing an ethylene alpha-olefin copolymer comprising: polymerizing ethylene and at least one alpha-olefin by contacting the ethylene and the at least one alpha-olefin with the catalyst system of any of claims 1-23 in at least one slurry phase reactor at a reactor pressure of 0.7 to 70bar and a reactor temperature of 60 ℃ to 130 ℃ to form an ethylene alpha-olefin copolymer.

32. An ethylene alpha-olefin copolymer obtained by contacting ethylene, at least one alpha-olefin, and the catalyst system of any of claims 1-23 in at least one slurry phase reactor, the copolymer having a density of 0.890g/cc or greater, a melt flow index of 0.1 to 80g/10min, and a Mw/Mn of 2.5 to 12.5.

33. A polyethylene composition comprising:

ethylene derived units and 0.5-20 wt% of C₃-C₁₂α -olefin derived units;

MI is 0.1-6g/10 min;

a density of 0.890 to 0.940 g/cc;

HLMI is 5-40g/10 min;

Tw₁-Tw₂the value is greater than-36 ℃;

Mw₁/Mw₂the value is 0.9 to 4;

Mw/Mn is from 5 to 10;

Mz/Mw is from 2.5 to 3.5;

Mz/Mn is 15-25; and

g' (vis) is greater than 0.90.

34. A polyethylene composition comprising:

ethylene derived units and 0.5-20 wt% of C₃-C₁₂α -olefin derived units;

MI is 0.1-20g/10 min;

a density of 0.890 to 0.940 g/cc;

the melt index ratio I21/I2 is 25-45g/10 min;

Tw₁-Tw₂the value is less than-30 ℃;

Mw₁/Mw₂the value is 0.9 to 4;

Mw/Mn is from 5 to 10;

Mz/Mw is from 2.5 to 3.5;

Mz/Mn is 15-25; and

g' (vis) is greater than 0.90.

35. A film comprising the polyethylene composition of any one of claims 27, 28, 29, 32, 33 or 34.

Technical Field

The present invention provides multi-catalyst systems and methods of use thereof. Specifically, the catalyst system comprises four group 4 metallocene compounds, a support material, and an activator. The catalyst system can be used in olefin polymerization processes.

Background

Polyolefins are widely used commercially due to their robust physical properties. For example, various types of polyethylene, including high density, low density and linear low density polyethylenes, are some of the most commercially useful. Polyolefins are typically prepared using catalysts for polymerizing olefin monomers.

Low density polyethylenes are typically prepared at high pressure using free radical initiators or in a gas phase process using ziegler-natta or vanadium catalysts. The low density polyethylene typically has a density of about 0.916g/cm³. Use of selfThe usual low density polyethylene produced by radical initiators is known in the industry as "LDPE". LDPE is also known as "branched" or "heterogeneously branched" polyethylene due to the relatively high number of long chain branches extending from the main polymer backbone. Polyethylenes of similar density which do not contain branching are known as "linear low density polyethylenes" ("LLDPE") and are usually produced with conventional ziegler-natta catalysts or with metallocene catalysts. By "linear" is meant that the polyethylene has few, if any, long chain branches, and typically has a g' vis value of 0.97 or higher, for example 0.98 or higher. The polyethylene having a density of still greater is high density polyethylene ("HDPE"), e.g., a density greater than 0.940g/cm³And is typically prepared with a ziegler-natta or chromium catalyst. Very low density polyethylene ("VLDPE") can be produced by several different processes, which result in a typical density of 0.890 to 0.915g/cm³The polyethylene of (1).

Copolymers of polyolefins such as polyethylene have a comonomer, such as hexene, incorporated into the polyethylene backbone. These copolymers provide different physical properties compared to polyethylene alone and are typically produced in low pressure reactors using, for example, solution, slurry or gas phase polymerization processes. The polymerization can be carried out in the presence of catalyst systems such as those using ziegler-natta catalysts, chromium-based catalysts or metallocene catalysts.

Copolymer compositions such as resins have a compositional distribution, which refers to the distribution of comonomers that form short chain branches along the copolymer backbone. When the amount of short chain branching varies between copolymer molecules, the composition is said to have a "broad" composition distribution. The composition distribution is said to be "narrow" when the comonomer amount/1000 carbons is similar between copolymer molecules of different chain lengths.

The composition distribution affects the properties of the copolymer composition, such as stiffness, toughness, environmental stress crack resistance, and heat sealing, among other properties. The composition distribution of the polyolefin composition can be easily measured by, for example, Temperature Rising Elution Fractionation (TREF) or crystallization analysis fractionation (CRYSTAF).

The composition distribution of the copolymer composition is influenced by the nature of the catalyst(s) used to form the polyolefin of the composition. Ziegler-natta catalysts and chromium-based catalysts tend to produce compositions with a broad composition distribution, while metallocene catalysts generally produce compositions with a narrow composition distribution.

In addition, polyolefins such as polyethylene having high molecular weights typically have desirable mechanical properties compared to their lower molecular weight counterparts. However, high molecular weight polyolefins can be difficult to process and can be expensive to produce. Polyolefin compositions having a bimodal molecular weight distribution are desirable because they can combine the advantageous mechanical properties of the high molecular weight portion of the composition with improved processability of the low molecular weight portion of the composition.

For example, useful bimodal polyolefin compositions include a first polyolefin having a low molecular weight and a high comonomer content (i.e., comonomer incorporated into the polyolefin backbone), while a second polyolefin has a high molecular weight and a low comonomer content. As used herein, "low comonomer content" is defined as a polyolefin having 6 wt% or less comonomer based on the total weight of the polyolefin. The high molecular weight fraction produced by the second catalyst may have a high comonomer content. As used herein, "high comonomer content" is defined as a polyolefin having greater than 6 wt% comonomer, based on the total weight of the polyolefin.

There are several methods of producing bimodal or broad molecular weight distribution polyolefins, such as melt blending, polymerization in reactors configured in series or parallel, or polymerization in a single reactor using a bimetallic catalyst. However, these methods, such as melt blending, are difficult to fully homogenize the polyolefin composition and have high costs.

In addition, the synthesis of these bimodal polyolefin compositions using a mixed catalyst system will include a first catalyst to catalyze the polymerization of, for example, ethylene under conditions substantially similar to a second catalyst, while not interfering with the polymerization catalysis of the second catalyst.

There is a need for catalyst systems that provide polyolefin compositions having a new combination of comonomer content fraction and molecular weight. There is a further need for new multi-catalyst systems in which one catalyst does not inhibit the polymerization catalysis of any other catalyst, and vice versa.

Catalysts for olefin polymerization are typically based on cyclopentadienyl transition metal catalyst compounds as catalyst precursors, in combination with an activator (typically an alumoxane) or with an activator containing a non-coordinating anion. Typical metallocene catalyst systems include a metallocene catalyst, an activator, and an optional support. Supported catalyst systems are used in many polymerization processes, often in slurry or gas phase polymerization processes.

For example, U.S. Pat. No.7829495 discloses Me₂Si (fluorenyl) (3-nPr-Cp) ZrCl₂And U.S. Pat. No.7179876 discloses loaded (nPrCp)₂HfMe₂。

Furthermore, Stadelhofer, j.; weidlein, j.; haaland, A.J. organomet.chem.1975, 84, C1-C4 discloses the preparation of potassium cyclopentadienide.

Furthermore, Me has already been synthesized₂C(Cp)(Me₃SiCH₂-Ind)MCl₂And Me₂C(Cp)(Me，Me₃SiCH₂-Ind)MCl₂(wherein M is Zr or Hf) and screened for syndiotactic polymerization of propylene; see Leino, r., Gomez, f.; cole, a.; waymouth, r. macromolecules2001, 34, 2072-.

Metallocenes are often combined with other catalysts, or even other metallocenes, to attempt to alter polymer properties. See, for example, U.S. patent nos. 8088867 and 5516848, which disclose the use of two different cyclopentadienyl-based transition metal catalyst compounds activated with an aluminoxane or a non-coordinating anion. See also PCT/US2016/021748 filed 3/10/2016, which discloses two metallocenes for the preparation of ethylene copolymers.

Also, Me has been synthesized₂C(Cp)(Me₃SiCH₂-Ind)MCl₂And Me₂C(Cp)(Me，Me₃SiCH₂-Ind)MCl₂(wherein M is Zr or Hf) and screened for syndiotactic polymerization of propylene; see Leino, r., Gomez, f.; cole, a.; waymouth, r. macromolecules2001, 34, 2072-.

Additional references of interest include: immobilized Me of Hong et al₂Si(C₅Me₄)(N-t-Bu)TiCl₂/(nBuCp)₂ZrCl₂Hybrid Metallocene Catalyst System for the Production of Poly (ethylene-co-hexane) with Psuedo-bimodulal Molecular Weight and InversElectromer Distribution, (Polymer Engineering and Science-2007, DOI10.1002/pen, p. 131-139, published on-line in Wiley Interscience (www.interscience.wiley.com)2007Society of Plastics Engineers); kim, j.d. et al, j.polym.sci.part a: polymchem, 38, 1427 (2000); iedema, p.d. et al, ind.eng.chem.res., 43, 36 (2004); U.S. patent nos. 4701432; 5032562, respectively; 5077255, respectively; 5135526, respectively; 5183867, respectively; 5382630, respectively; 5382631, respectively; 5525678, respectively; 6069213, respectively; 6207606, respectively; 6656866, respectively; 6828394, respectively; 6964937, respectively; 6956094, respectively; 6964937, respectively; 6995109, respectively; 7041617, respectively; 7119153, respectively; 7129302, respectively; 7141632, respectively; 7172987, respectively; 7179876, respectively; 7192902, respectively; 7199072, respectively; 7199073, respectively; 7226886, respectively; 7285608, respectively; 7312283, respectively; 7355058, respectively; 7385015, respectively; 7396888, respectively; 7595364, respectively; 7619047, respectively; 7662894, respectively; 7829495, respectively; 7855253, respectively; 8110518, respectively; 8138113, respectively; 8268944, respectively; 8288487, respectively; 8329834, respectively; 8378029, respectively; 8575284, respectively; 8598061, respectively; 8680218, respectively; 8785551, respectively; 8815357, respectively; 8940842, respectively; 8957168, respectively; 9079993, respectively; 9163098, respectively; 9181370, respectively; 9303099, respectively; U.S. publication No. 2004/259722; 2006/275571, respectively; 2007/043176, respectively; 2010/331505, respectively; 2012/0130032, respectively; 2014/0031504, respectively; 2014/0127427, respectively; 2015/299352, respectively; 2016/0032027, respectively; 2016/075803, respectively; PCT publication No. WO97/35891; WO 98/49209; WO 00/12565; WO 2001/09200; WO 02/060957; WO 2004/046214; WO 2006/080817; WO 2007/067259; WO 2007/080365; WO 2009/146167; WO 2012/006272; WO 2012/158260; WO 2014/0242314; WO 2015/123168; WO 2016/172099; PCT application No. PCT/US2016/021757, filed 3, 10, 2016; EP 2374822; EP 2003166; EP 0729387; EP 0676418; EP 0705851; KR 20150058020; KR 101132180; the results of Sheu, s, 2006,"Enhanced Bimodal PE masks the allowable, http:// www.tappi.org/content/06as area/pdfs-Enhanced/Enhanced. pdf; and Chen et al, "Modeling and Simulation of Borstar Bimodal Polyethylene Process Based on one Rigorous PC-SAFT evaluation of State Model", Industrial&Engineering chemical research, 53, 19905 and 19915, (2014). Other references of interest include: U.S. publication No.2015/0322184 and A.Calhoun et al, "Polymer Chemistry", Chapter 5, pages 77-87.

There remains a need in the art for new and improved catalyst systems for olefin polymerization to achieve increased activity or enhanced polymer properties, to increase conversion or comonomer incorporation, or to alter comonomer distribution. There is also a need for supported catalyst systems and methods of using such catalyst systems to polymerize olefins (e.g., ethylene) to provide ethylene polymers having unique properties of high stiffness, high toughness, and good processability.

Summary of The Invention

The present invention provides a supported catalyst system comprising four group 4 metallocene compounds; a carrier material; and an activator, wherein the catalyst system comprises:

a) at least two different catalysts represented by formula (A):

wherein:

m is Hf or Zr;

each R¹，R²And R⁴Independently is hydrogen, alkoxy or C₁-C₄₀A substituted or unsubstituted hydrocarbyl group;

each R⁷，R⁸，R⁹And R¹⁰Independently of one another is hydrogen, alkoxy, C₁-C₄₀Substituted or unsubstituted hydrocarbyl, -CH₂-SiR'₃or-CH₂-CR'₃Wherein each R' is independently C₁-C₂₀A substituted or unsubstituted hydrocarbyl group, provided that R⁷，R⁸，R⁹And R¹⁰is-CH₂-SiR'₃or-CH₂-CR'₃Preferably R⁸And/or R⁹is-CH₂-SiR'₃or-CH₂-CR'₃(ii) a Preferably R⁹is-CH₂-SiR'₃or-CH₂-CR'₃；

T¹Is a bridging group; and

b) at least two different catalysts represented by formula (B):

T² _yCp_mM¹X_q(B)

wherein:

each Cp is independently a cyclopentadienyl, indenyl, or fluorenyl, which may be independently substituted or unsubstituted;

M¹is zirconium or hafnium;

T²is a bridging group;

y is 0 or 1, which means that T is absent or present²；

X is halo, hydrido, alkyl, alkenyl or arylalkyl;

m is 2 or 3, q is 0, 1, 2 or 3, and the sum of m + q is equal to the oxidation state of the transition metal, typically 2, 3 or 4; and

each Cp and X is bound to M¹The above step (1);

c) a carrier material; and

d) an activator.

The invention also provides a process for polymerizing monomers (e.g., olefin monomers) comprising contacting one or more monomers with the supported catalyst system described above.

The present invention also provides a process for producing an ethylene polymer composition comprising: i) in a single reaction zone, in gas or slurry phase, ethylene and C₃-C₂₀Contacting the comonomer with a catalyst system comprising a support, an activator, and the catalyst system described above, and ii) obtaining an in situ ethylene polymer composition having at least 50 mole percent ethylene and a density of 0.890g/cc or greater, alternatively 0.910g/cc or greater, alternatively 0.935g/cc or greater.

The present invention also provides a process for producing an ethylene polymer composition comprising: i) in a single reaction zone, in gas or slurry phase, ethylene and C₃-C₂₀The comonomer is contacted with a catalyst system comprising a support, an activator and the above catalyst system, and an ethylene polymer is obtained having: a) a density of 0.890g/cc or more, b) a melt flow index (ASTM1238, 190 ℃, 2.16kg) of 0.1 to 80dg/min, c) a Mw/Mn of 2.5 to 12.5.

The invention also provides polymer compositions produced by the methods and catalyst systems described herein.

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Mixed catalyst system with four metallocenes on a single support

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