Aluminoxane-activated metallocene catalysts

1. A catalyst system wherein the catalyst system consists of:

(i) one metallocene complex, wherein the one metallocene complex is of formula (I):

wherein

Mt1 is Hf,

X is a sigma-donor ligand,

R 1 , R 2 , R 3 are the same or different from each other and are hydrogen or a saturated linear or branched C 1 -C 10 alkyl group, wherein the alkyl group optionally comprises up to 2 heteroatoms belonging to groups 14-16 of the periodic table, or wherein R 1 and R 2 or R 2 and R 3 form a ring having 4 to 6 C-atoms and 1 to 3 double bonds,

R 4 and R 5 are the same or different from each other and are 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 optionally comprise up to 2 heteroatoms belonging to groups 14-16 of the periodic table,

n is 1 to 5,

Ar is a C 6 -C 20 -aryl or -heteroaryl group, which is unsubstituted or substituted by 1 to 5 linear or branched C 1 -C 10 alkyl group(s),

and

(ii) an aluminoxane cocatalyst, and

(iii) optionally an aluminium alkyl compound Al(R 7 ) 3 , with R 7 being a linear or branched C2-C8-alkyl group;

or

wherein the catalyst system consists of

(i) two metallocene complexes, present as a mixture of the metallocene complex of formula (I) with a metallocene complex of formula (I′):

wherein Mt2 is Zr, R 1 to R 5 and Ar are defined as for the complex of formula (I), provided that the mixture comprises more than 50% by moles of the complex of formula (I) with Mt1 being Hf; and

(ii) an aluminoxane cocatalyst, and

(iii) optionally an aluminium alkyl compound Al(R 7 ) 3 , with R 7 being a linear or branched C2-C8-alkyl group;

wherein the catalyst system shows a reactivity ratio C AO /C 2 of at least 0.1, wherein AO is C4-10 alpha-olefin comonomer, in a high temperature solution process.

2. The catalyst system of claim 1 , wherein in the formula (I):

Mt1 is Hf,

X is independently a hydrogen atom, a halogen atom, a R 6 , OR 6 , OSO 2 CF 3 , OCOR 6 , SR 6 , NR 6 2 or PR 6 2 group, wherein R 6 is a linear or branched, cyclic or acyclic, C 1 -C 20 -alkyl, C 2 -C 20 -alkenyl, C 2 -C 20 -alkynyl, C 6 -C 20 -aryl, C 7 -C 20 -alkylaryl or C 7 -C 20 -arylalkyl radical, optionally comprising up to 2 heteroatoms belonging to groups 14-16 of the periodic table, or is SiR 6 3 , SiHR 6 2 or SiH 2 R 6 ,

R 1 , R 2 , R 3 are the same or different from each other and are hydrogen or a saturated linear or branched C 1 -C 6 alkyl group, wherein the alkyl group does not comprise any heteroatom belonging to groups 14-16 of the periodic table, or R 1 is hydrogen and R 2 and R 3 form a ring having 5 to 6 C-atoms and 1 to 3 double bonds,

R 4 and R 5 are the same or different from each other and are a saturated linear or branched C 1 -C 10 alkyl or C 6 -C 10 aryl group, wherein the groups do not comprise any heteroatom belonging to groups 14-16,

Ar is a C 6 -C 10 -aryl or -heteroaryl group, which is unsubstituted or substituted by one linear or branched C 1 -C 6 alkyl group, and wherein

n is 2 to 4.

3. The catalyst system of claim 2 , wherein in the formula (I):

Mt1 is Hf,

X is independently a halogen atom or a R 6 or OR 6 group, wherein R 6 is a C 1-6 -alkyl, phenyl or benzyl group,

R 1 , R 2 , R 3 are the same or different from each other and are hydrogen, a saturated linear or branched C 1 -C 4 alkyl group, wherein the alkyl group does not comprise any heteroatom belonging to groups 14-16 of the periodic table, or R 1 is hydrogen and R 2 and R 3 form a ring having 6 C-atoms and 3 double bonds,

R 4 and R 5 are the same or different from each other and are a saturated linear or branched C 1 -C 6 alkyl or phenyl group, wherein the groups do not comprise any heteroatoms belonging to groups 14-16 of the periodic table,

Ar is an unsubstituted C 6 -C 10 -aryl group, and n is 2 to 4.

4. The catalyst system of claim 3 , wherein in the formula (I):

Mt1 is Hf,

X is independently a methyl, chloro or benzyl group,

R 1 , R 2 , R 3 are the same and are all hydrogen or R 1 is hydrogen and R 2 and R 3 form a ring having 6 C-atoms and 3 double bonds,

R 4 and R 5 are the same and are a saturated linear or branched C 2 -C 6 alkyl group,

n is 2 to 4, and Ar is phenyl.

5. The catalyst system of claim 1 , wherein the metallocene complex of formula (I) is selected from:

(phenyl)(but-3-en-1-yl)methylene(cyclopentadienyl)(2,7-di-tert-butylfluoren-9-yl)hafnium dimethyl,

(phenyl)(but-3-en-1-yl)methylene(cyclopentadienyl)(2,7-di-tert-butylfluoren-9-yl)hafnium dibenzyl,

(phenyl)(but-3-en-1-yl)methylene(cyclopentadienyl)(2,7-di-tert-butylfluoren-9-yl)hafnium dichloride,

(phenyl)(4-penten-1-yl)methylene(cyclopentadienyl)(2,7-di-tert-butylfluorenyl)hafnium dimethyl,

(phenyl)(4-penten-1-yl)methylene(cyclopentadienyl)(2,7-di-tert-butylfluorenyl)hafnium dibenzyl,

(phenyl)(4-penten-1-yl)methylene(cyclopentadienyl)(2,7-di-tert-butylfluorenyl)hafnium dichloride,

(phenyl)(5-hexen-1-yl)methylene(cyclopentadienyl)(2,7-di-tert-butylfluoren-9-yl)hafnium dimethyl,

(phenyl)(5-hexen-1-yl)methylene(cyclopentadienyl)(2,7-di-tert-butylfluoren-9-yl)hafnium dibenzyl, or

(phenyl)(5-hexen-1-yl)methylene(cyclopentadienyl)(2,7-di-tert-butylfluoren-9-yl)hafnium dichloride,

and which is optionally mixed with a corresponding metallocene complex of formula (I′):

wherein Mt2 is Zr, R 1 to R 5 and Ar are defined as for the complex of formula (I), provided that the mixture comprises more than 50% by moles of the complex of formula (I) with Mt1 being Hf.

6. The catalyst system of claim 1 , wherein the catalyst system is homogeneous or non-supported catalyst systems, wherein the catalyst system is prepared in a solution, by contacting the metallocene complex of formula (I) or a mixture of the metallocene complex of formula (I) with a metallocene complex of formula (I′):

wherein Mt2 is Zr, R 1 to R 5 and Ar are defined as for the complex of formula (I), provided that the mixture comprises more than 50% by moles of the complex of formula (I) with Mt1 being Hf, as a solid or as a solution, with the cocatalyst in a hydrocarbon diluent or previously dissolved in an aromatic solvent, or which is formed by sequentially adding the catalyst system components directly into a polymerization reactor.

7. The catalyst system of claim 1 , wherein the aluminoxane cocatalyst is methylaluminoxane.

8. The catalyst system of claim 1 , wherein the aluminium alkyl compound of the formula Al(R 7 ) 3 with R 7 being a linear or branched C 2 -C 8 -alkyl group is present, and wherein the aluminium alkyl compound of the formula Al(R 7 ) 3 together with the aluminoxane are used as cocatalyst.

9. The catalyst system of claim 8 , wherein the cocatalyst is a reaction product of the aluminoxane with the aluminium alkyl compound Al(R 7 ) 3 .

10. A process for preparing a catalyst system of claim 1 , comprising an activation method comprising contacting at least one metallocene complex of formula (I):

wherein

Mt1 is Hf,

X is a sigma-donor ligand,

R 1 , R 2 , R 3 are the same or different from each other and are hydrogen or a saturated linear or branched C 1 -C 10 alkyl group, wherein the alkyl group optionally comprises up to 2 heteroatoms belonging to groups 14-16 of the periodic table, or wherein R 1 and R 2 or R 2 and R 3 form a ring having 4 to 6 C-atoms and 1 to 3 double bonds,

R 4 and R 5 are the same or different from each other and are 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 optionally comprise up to 2 heteroatoms belonging to groups 14-16 of the periodic table,

n is 1 to 5,

Ar is a C 6 -C 20 -aryl or -heteroaryl group, which is unsubstituted or substituted by 1 to 5 linear or branched C 1 -C 10 alkyl group(s),

optionally mixed with a metallocene complex of formula (I′):

wherein Mt2 is Zr, R 1 to R 5 and Ar are defined as for the complex of formula (I), provided that the mixture comprises more than 50% by moles of the complex of formula (I) with Mt1 being Hf,

with a reaction product of an aluminoxane cocatalyst with an aluminium alkyl compound Al(R 7 ) 3 , with R 7 being a linear or branched C 2 -C 8 -alkyl group, before being introduced into a polymerization reactor.