Catalyst system for producing polyethylene copolymers in a high temperature solution polymerization process
Catalyst system for producing ethylene copolymers in a high temperature solution process, the catalyst system comprising (i) a metallocene complex of formula (I), M is Hf or a mixture with Zr, provided that more than 50% by moles of the complex of Formula I has M=Hf, X is a sigma ligand, R are the same or different from each other and can be saturated linear or branched C 1 -C 10 alkyl, C 5 -C 10 aryl, C 6 -C 20 alkylaryl or C 6 -C 20 arylalkyl groups, which can optionally contain up to 2 heteroatoms or silicon atoms, R 1 is a C 6 -C 20 -aryl, which can be unsubstituted or substituted by one or up to 5 linear or branched C 1 -C 10 alkyl group(s), R 2 is a saturated linear or cyclic C 3 -C 20 alkyl group or a branched CR 3 R 4 R 5 group, wherein R 3 is hydrogen or an C 1 -C 20 alkyl group and R 4 and R 5 are the same or are different and can be an C 1 -C 20 alkyl group and (ii) a boron containing cocatalyst.
1. A catalyst system for producing ethylene copolymers in a high temperature solution process at temperatures higher than 100° C., the catalyst system comprising:
(i) a metallocene complex of formula (I)
wherein
M is Hf;
each X is independently a C 1-6 alkyl, benzyl or a halogen atom;
R's are the same or different and are independently selected from the group consisting of linear or branched C 1 -C 10 alkyl;
R 1 is phenyl, which is unsubstituted or substituted by one linear or branched C 1 -C 10 alkyl group; and
R 2 is a linear or cyclic C 3 -C 20 alkyl group or a branched CR 3 R 4 R 5 group, wherein R 3 is hydrogen or a C 1 -C 20 alkyl group and R 4 and R 5 are the same or are different and are independently a C 1 -C 20 alkyl group;
and
(ii) a boron containing cocatalyst;
wherein the catalyst system is a homogeneous or non-supported catalyst system.
2. The catalyst system according to claim 1 , wherein in the formula (I):
R's are the same or different and are independently selected from the group consisting of linear or branched C 1 -C 6 alkyl;
R 1 is phenyl, which is unsubstituted or substituted by one linear or branched C 1 -C 6 alkyl group; and
R 2 is a linear or cyclic C 3 -C 10 alkyl group or a branched CR 3 R 4 R 5 group, wherein R 3 is hydrogen and R 4 and R 5 are the same or are different and are independently a C 1 -C 10 alkyl group.
3. The catalyst system according to claim 2 , wherein in the formula (I):
R's are the same and are a linear or branched C 1 -C 6 alkyl;
R 1 is phenyl; and
R 2 is a linear or cyclic C 5 -C 10 alkyl group or a branched CR 3 R 4 R 5 group, wherein R 3 is hydrogen and R 4 and R 5 are the same or are different and are independently a C 1 -C 3 alkyl group.
4. The catalyst system according to claim 3 , wherein in the formula (I):
each X is independently a methyl, benzyl, or chloride group;
R's are the same and are all methyl groups; and
R 2 is i-propyl, n-hexyl, or cyclohexyl.
5. The catalyst system according to claim 1 , wherein the metallocene complex of formula (I) is (Phenyl)(cyclohexyl) methylene(cyclopentadienyl)(2,7-di-tert-butylfluoren-9-yl)hafnium dibenzyl; (Phenyl)(cyclohexyl)methylene(cyclopentadienyl)(2,7-di-tert-butylfluoren-9-yl)hafnium dimethyl; (Phenyl)(isopropyl)methylene(cyclopentadienyl)(2,7-di-tert-butylfluoren-9-yl)hafnium dibenzyl; (Phenyl)(isopropyl)methylene(cyclopentadienyl)(2,7-di-tert-butylfluoren-9-yl)hafnium dimethyl; (Phenyl)(1-hexyl)methylene(cyclopentadienyl)(2,7-di-tert-butylfluoren-9-yl)hafnium dibenzyl; (Phenyl)(1-hexyl)methylene(cyclopentadienyl)(2,7-di-tert-butylfluoren-9-yl)hafnium dimethyl; (Phenyl)(cyclopentyl)methylene(cyclopentadienyl)(2,7-di-tert-butylfluoren-9-yl)hafnium dibenzyl; (Phenyl)(cyclopentyl)methylene(cyclopentadienyl)(2,7-di-tert-butylfluoren-9-yl)hafnium dimethyl; (para-isopropylphenyl)(cyclohexyl)methylene (cyclopentadienyl)(2,7-di-tert-butylfluoren-9-yl)hafnium dibenzyl; (para-isopropylphenyl) (cyclohexyl)methylene(cyclopentadienyl)(2,7-di-tert-butylfluoren-9-yl)hafnium dimethyl; (para-isopropylphenyl)(isopropyl)methylene(cyclopentadienyl)(2,7-di-tert-butylfluoren-9-yl)hafnium dibenzyl; (para-isopropylphenyl)(isopropyl)methylene(cyclopentadienyl)(2,7-di-tert-butylfluoren-9-yl)hafnium dimethyl; (para-isopropylphenyl)(1-hexyl)methylene (cyclopentadienyl)(2,7-di-tert-butylfluoren-9-yl)hafnium dibenzyl; (para-isopropylphenyl)(1-hexyl)methylene(cyclopentadienyl)(2,7-di-tert-butylfluoren-9-yl)hafnium dimethyl; (para-isopropylphenyl)(cyclopentyl)methylene(cyclopentadienyl)(2,7-di-tert-butylfluoren-9-yl)hafnium dibenzyl; or (para-isopropyl)(cyclopentyl)methylene(cyclopentadienyl)(2,7-di-tert-butylfluoren-9-yl)hafnium dimethyl.
6. The catalyst system as claimed in claim 1 , wherein said boron containing cocatalyst comprises an anion of formula:
( Z ) 4 B − (II)
where Z is an optionally substituted phenyl derivative, said substituent being a halo-C 1-6 -alkyl or halide group.
7. The catalyst system according to claim 1 , wherein all R's are the same and are a linear or branched C 1 -C 6 alkyl.
8. The catalyst system according to claim 1 , wherein:
the catalyst system is prepared in solution by contacting the metallocene complex of Formula (I), as a solid or as a solution, with the cocatalyst in a hydrocarbon diluent or previously dissolved in an aromatic solvent, or
the catalyst system is formed by sequentially adding the components of the catalyst system directly into a polymerization reactor.
9. The catalyst system as claimed in claim 1 , wherein said boron containing cocatalyst is selected from the group consisting of triphenylcarbeniumtetrakis (pentafluorophenyl) borate, N,N-dimethylcyclohexylammoniumtetrakis(pentafluorophenyl) borate, N,N-dimethylbenzylammoniumtetrakis(pentafluorophenyl)borate, and N,N-dimethylaniliniumtetrakis(pentafluorophenyl)borate.
10. The catalyst system of claim 1 , wherein in the formula (I) R's are the same and are all methyl groups.
11. The catalyst system of claim 1 , wherein in the formula (I) R 2 is i-propyl, n-hexyl, or cyclohexyl.
12. The catalyst system of claim 1 , wherein in the formula (I) R 1 is unsubstituted phenyl.
13. The catalyst system of claim 1 , wherein in the formula (I) each X is independently a methyl, benzyl, or chloride group.
14. The catalyst system of claim 1 , wherein the metallocene complex of formula (I) is (Phenyl)(cyclohexyl)methylene(cyclopentadienyl)(2,7-di-tert-butylfluoren-9-yl)hafnium dimethyl; (Phenyl)(isopropyl)methylene(cyclopentadienyl)(2,7-di-tert-butylfluoren-9-yl)hafnium dimethyl; or (Phenyl)(1-hexyl)methylene(cyclopentadienyl)(2,7-di-tert-butylfluoren-9-yl)hafnium dimethyl.
15. The catalyst system of claim 1 , wherein said boron containing cocatalyst comprises N,N-Dimethylanilinium Tetrakis(pentafluorophenyl)borate.
16. The catalyst system of claim 1 , wherein the metallocene complex of formula (I) and the boron containing cocatalyst are provided in a molar ratio of boron to Hf of 1:1 to 5:1 mol/mol.
17. The catalyst system of claim 1 , the metallocene complex of formula (I) and the boron containing cocatalyst are provided in a molar ratio of boron to Hf of 1:1 to less than 2:1 mol/mol.