Process for the preparation of polyolefins having a broad molecular weight distribution

Claim 2

A process for the preparation of a polyolefin which has a molecular weight distribution M w /M n of ≧3.0 and which may be monomodal, bimodal or multimodal, by polymerization or copolymerization of an olefin, consisting essentially of propylene, at a temperature of from -60° to 200° C., at a pressure of from 0.5 to 100 bar, in solution, in suspension or in the gas phase, in the presence of a catalyst comprising a transition-metal component (metallocene) and an aluminoxane of the formula II ##STR12## for the linear type and/or of the formula III ##STR13## for the cyclic type, where, in the formulae II and III, the radicals R are identical or different and are a C 1 -C 6 -alkyl group, a C 1 -C 6 -fluoroalkyl group, a C 6 -C 18 -aryl group, a C 1 -C 6 -fluoroaryl group or hydrogen, and n is an integer from 0 to 50, or, instead of the aluminoxane, comprises a mixture of an aluminoxane of the formula II and/or of the formula III with a compound AlR 3 , which comprises using, as the transition-metal component, at least one zirconocene of the formula I and at least one zirconocene of the formula Ia or alternatively at least 2 zirconocenes of the formula I ##STR14## in which R 1 and R 2 are identical or different and are a hydrogen atom, a C 1 -C 10 -alkyl group, a C 1 -C 10 -alkoxy group, a C 6 -C 10 -aryl group, a C 6 -C 10 -aryloxy group, a C 2 -C 10 -alkenyl group, a C 7 -C 40 -arylalkyl group, a C 7 -C 40 -alkylaryl group, a C 8 -C 40 -arylalkenyl group or a halogen atom, R 3 and R 4 are identical or different and are a hydrogen atom, a halogen atom, a C 1 -C 10 -alkyl group, which is optionally halogenated, a C 6 -C 10 -aryl group, or a --NR 2 10 , --SR 10 , --OSiR 3 10 , --SIR 3 10 or --PR 2 10 radical, in which R 10 is a halogen atom, a C 1 --C 10 -alkyl group or a C 6 -C 10 -aryl group, R 5 and R 6 are identical or different and are as defined for R 3 and R 4 with the proviso that R 5 and R 6 are not hydrogen, R 7 is ##STR15## ═BR 11 , ═AlR 11 , --Ge--, --Sn, --O--, --S--, ═SO, ═SO 2 , ═NR 11 , ═CO, ═PR 11 or ═P(O)R 11 , where R 11 , R 12 and R 13 are identical or different and are a hydrogen atom, a halogen atom, a C 1 -C 10 -alkyl group, a C 1 -C 10 -fluoroalkyl group, A C 6 -C 10 -aryl group, a C 6 -C 10 -fluoroaryl group, a C 1 -C 10 -alkoxy group, a C 2 -C 10 -alkenyl group, a C 7 -C 40 -arylalkyl group, a C 8 -C 40 -arylalkenyl group or a C 7 -C 40 -alkylaryl group, or R 11 and R 12 or R 11 and R 13 , together with the atoms connecting them, in each case form a ring, and M 1 is silicon, germanium or tin, R 8 and R 9 are identical or different and are as defined for R 11 , R 14 and R 15 are identical or different and are monocyclic or polycyclic hydrocarbon radicals which can form a sandwich structure together with the zirconium atom, and m and n are identical or different and are zero, 1 or 2, where m plus n is zero, 1 or 2.

Claim 3

The process as claimed in claim 1, wherein, in the formula I, R 1 and R 2 are identical or different and are methyl or chlorine, R 3 and R 4 are hydrogen, R 5 and R 6 are identical or different and are methyl, ethyl or trifluoromethyl, R 7 is a ##STR16## radical, and n plus m is zero or 1.

Claim 4

The process as claimed in claim 1, wherein, in the formula Ia, R 1 and R 2 are identical or different and are methyl or chlorine, R 7 is a ##STR17## radical, n+m is zero or 1 and R 14 and R 15 are identical or different and are fluorenyl, idenyl or substituted cyclopentadienyl.

Claim 5

The process as claimed in claim 1, wherein propylene is polymerized in combination with a minor amount of ethylene.

Claim 6

The process as claimed in claim 1, wherein an isotactic index is in the range of 91.6 to 98.5.

Claim 7

The process as claimed in claim 1, wherein R 3 and R 4 are a hydrogen atom.

Claim 8

The process as claimed in claim 1, wherein R 11 , R 12 , and R 13 , are C 1 -C 4 -alkyl group, CF 3 group, C 6 -C 8 -aryl group, pentafluorophenyl group, C 1 -C 4 -alkoxy group, C 2 -C 4 -alkenyl group, C 7 -C 10 -arylalkyl group, C 8 -C 12 -arylalkenyl group, or a C 7 -C 12 -alkylaryl group.

Claim 9

The process as claimed in claim 1, wherein M 1 is silicon or germanium.

Claim 10

The process as claimed in claim 1, wherein there are either two or three zirconocenes.

Claim 11

The process as claimed in claim 1, wherein n' is an integer from 10 to 35.

Claim 12

The process as claimed in claim 1, wherein R is methyl.

Claim 13

The process as claimed in claim 1, wherein, in said formula Il R 1 and R 2 are halogen; R 5 and R 6 are C 1 -C 10 -alkyl; R 7 is ##STR18## M 1 is silicon; and m and n are zero.

Claim 14

A process for the preparation of a monomodal, bimodal, or multimodal polyolefin having a molecular weight distribution M w /M n of ≧3.0, comprising: polymerizing an olefin of the formula R a CH═CHR b in which R a and R b are identical or different and are a hydrogen atom or an alkyl radical having 1 to 14 carbon atoms, or R a and R b , together with the atoms connecting them, form a ring, at a temperature for from -60° to 200° C., in suspension or in the gas phase, in the presence of a catalyst comprising a zirconocene component and an aluminoxane component, said aluminoxane component comprising an aluminoxane of the formula ##STR19## for the linear type or of the formula (III) ##STR20## for the cyclic type, where, in the formulae II and III, the radicals R are identical or different and are a C 1 -C 6 -alkyl group, a C 1 -C 6 -fluoroalkyl group, a C 6 -C 18 -aryl group, a C 1 -C 6 -fluoroaryl group or hydrogen, and n' is an number from 0 to 50, said aluminoxane component optionally containing a compound of the formula AlR 3 ; said zirconocene component comprising at least one zirconocene of the formula I and at least one zirconocene of the formula Ia or alternatively at least 2 zirconocenes of the formula I ##STR21## in which R 1 and R 2 are identical or different and are a hydrogen atom, a C 1 -C 10 -alkyl group, a C 1 -C 10 -alkoxy group, a C 6 -C 10 -aryl group, a C 6 -C 10 -aryloxy group, a C 2 -C 10 -alkenyl group, a C 7 -C 40 -arylalkyl group, a C 7 -C 40 -alkylaryl group, a C 8 -C 40 -arylalkenyl group or a halogen atom, R 7 is ##STR22## ═BR 11 , ═AlR 11 , --Ge--, --Sn, --O--, --S--, ═SO, ═SO 2 , ═NR 11 , ═CO, ═PR 11 or ═P(O)R 11 , wherein R 11 , R 12 and R 13 are identical or different and are a hydrogen atom, a halogen atom, a C 1 -C 10 -alkyl group, a C 1 -C 10 -fluoroalkyl group, a C 6 -C 10 -aryl group, a C 6 -C 10 -fluoroaryl group, a C 1 -C 10 -alkoxy group, a C 2 -C 10 -alkenyl group, a C 7 -C 40 -arylalkyl group, a C 8 -C 40 -arylalkenyl group or a C 7 -C 40 -alkylaryl group, or R 11 and R 12 or R 11 and R 13 , together with the atoms connecting them, in each case form a ring, and M 1 is silicon, germanium or tin, R 8 and R 9 are identical or different and are as defined for R 11 , R 14 and R 15 are identical or different and are a monocyclic or polycyclic hydrocarbon radical which can form a sandwich structure together with the zirconium atom, and m and n are identical or different and are zero, 1 or 2, where m plus n is zero, 1 or 2, and A is ethylene, methylethylene, dimethyl silyl, diphenylsilyl, or phenyl(methyl) silyl.

Claim 15

A process for the preparation of a monomodal, bimodal, or multimodal polyolefin having a molecular weight distribution M w /M n of ≧3.0, comprising: polymerizing an olefin of the formula R a CH═CHR b in which R a and R b are identical or different and are a hydrogen atom or an alkyl radical having 1 to 14 carbon atoms, or R a and R b , together with the atoms connecting them, form a ring, at a temperature for from -60° to 200° C., in suspension or in the gas phase, in the presence of a catalyst comprising a zirconocene component and an aluminoxane component, said aluminoxane component comprising an aluminoxane of the formula ##STR19## for the linear type or of the formula (III) ##STR20## for the cyclic type, where, in the formulae II and III, the radicals R are identical or different and are a C 1 -C 6 -alkyl group, a C 1 -C 6 -fluoroalkyl group, a C 6 -C 18 -aryl group, a C 1 -C 6 -fluoroaryl group or hydrogen, and n' is an number from 0 to 50, said aluminoxane component optionally containing a compound of the formula AlR 3 ; said zirconocene component comprising at least one zirconocene of the formula I and at least one zirconocene of the formula Ia or alternatively at least 2 zirconocenes of the formula I ##STR21## in which R 1 and R 2 are identical or different and are a hydrogen atom, a C 1 -C 10 -alkyl group, a C 1 -C 10 -alkoxy group, a C 6 -C 10 -aryl group, a C 6 -C 10 -aryloxy group, a C 2 -C 10 -alkenyl group, a C 7 -C 40 -arylalkyl group, a C 7 -C 40 -alkylaryl group, a C 8 -C 40 -arylalkenyl group or a halogen atom, R 7 is ##STR22## ═BR 11 , ═AlR 11 , --Ge--, --Sn, --O--, --S--, ═SO, ═SO 2 , ═NR 11 , ═CO, ═PR 11 or ═P(O)R 11 , wherein R 11 , R 12 and R 13 are identical or different and are a hydrogen atom, a halogen atom, a C 1 -C 10 -alkyl group, a C 1 -C 10 -fluoroalkyl group, a C 6 -C 10 -aryl group, a C 6 -C 10 -fluoroaryl group, a C 1 -C 10 -alkoxy group, a C 2 -C 10 -alkenyl group, a C 7 -C 40 -arylalkyl group, a C 8 -C 40 -arylalkenyl group or a C 7 -C 40 -alkylaryl group, or R 11 and R 12 or R 11 and R 13 , together with the atoms connecting them, in each case form a ring, and M 1 is silicon, germanium or tin, R 8 and R 9 are identical or different and are as defined for R 11 , R 14 and R 15 are identical or different and are a monocyclic or polycyclic hydrocarbon radical which can form a sandwich structure together with the zirconium atom, and m and n are identical or different and are zero, 1 or 2, where m plus n is zero, 1 or 2, and A is ethylene, methylethylene, dimethyl silyl, diphenylsilyl, or phenyl(methyl) silyl.

Claim 16

The process as claimed in claim 13, wherein propylene is polymerized, alone or in combination with ethylene.

Claim 17

A process for the preparation of a monomodal, bimodal, or multimodal polyolefin having a molecular weight distribution M w /M n of ≧3.0, comprising: polymerizing an olefin of the formula R a CH═CHR b in which R a and R b are identical or different and are a hydrogen atom or an alkyl radical having 1 to 14 carbon atoms, or R a and R b , together with the atoms connecting them, form a ring, at a temperature of from -60° to 200° C., in suspension or in the gas phase, in the presence of a catalyst comprising a zirconocene component and an aluminoxane component, said aluminoxane component comprising an aluminoxane of the formula ##STR23## for the linear type or of the formula (III) ##STR24## for the cyclic type, where, in the formulae II and III, the radicals R are identical or different and are a C 1 -C 6 -alkyl group, a C 1 -C 6 -fluoroalkyl group, a C 6 -C 18 -aryl group, a C 1 -C 6 -fluoroaryl group or hydrogen, and n' is a number from 0 to 50, said aluminoxane component optionally containing a compound of the formula AlR 3 ; said zirconocene component comprising at least one zirconocene of the formula I ##STR25## in which R 1 and R 2 are identical or different and are a hydrogen atom, a C 1 -C 10 -alkyl group, a C 1 -C 10 -alkoxy group, a C 6 -C 10 -aryl group, a C 6 -C 10 -aryloxy group, a C 2 -C 10 -alkenyl group, a C 7 -C 40 -arylalkyl group, a C 7 -C 40 -alkylaryl group, a C 8 -C 40 -arylalkenyl group or a halogen atom, R 3 and R 4 are identical or different and are a hydrogen atom, a halogen atom, a C 1 -C 10 -alkyl group, which is optionally halogenated, a C 6 -C 10 -aryl group, or a --NR 2 10 , --SR 10 , --OSiR 3 10 , SiR 3 10 or --PR 2 10 radical, in which R 10 is a halogen atom, a C 1 -C 10 -alkyl group or a C 6 -C 10 -aryl group, R 5 and R 6 are identical or different and are as defined for R 3 and R 4 , with the proviso that R 5 and R 6 are not hydrogen, R 7 is ##STR26## ═BR 11 , ═AlR 11 , --Ge--, --Sn, --O--, --S--, ═SO, ═SO 2 , ═NR 11 , ═CO, ═PR 11 or ═P(O)R 11 , where R 11 , R 12 and R 13 are identical or different and are a hydrogen atom, a halogen atom, a C 1 -C 10 -alkyl group, a C 1 -C 10 -fluoroalkyl group, a C 6 -C 10 -aryl group, a C 6 -C 10 -fluoroaryl group, a C 1 -C 10 -alkoxy group, a C 2 -C 10 -alkenyl group, a C 7 -C 40 -arylalkyl group, a C 8 -C 40 -arylalkenyl group or a C 7 -C 40 -alkylaryl group, or R 11 and R 12 or R 11 and R 13 , together with the atoms connecting them, in each case form ring, and M 1 is silicon, germanium or tin, R 8 and R 9 are identical or different and are as defined for R 11 , R 14 and R 15 are identical or different and are a monocyclic or polycyclic hydrocarbon radicals which can form a sandwich structure together with the zirconium atom, and m and n are identical or different and are zero, 1 or 2, where m plus n is zero, 1 or 2, and at least one of the following zirconocenes: rac-phenyl(methyl)silyl(indenyl) 2 zirconium dichloride, diphenylmethylene(9-fluorenyl) (cyclopentadienyl)zirconium dichloride, isopropylidene(9-fluorenyl) (cyclopentadienyl)zirconium dichloride, rac-dimethylsilyl (2,3,5-trimethyl-1-cyclopentadienyl) 2 zirconium dichloride, rac-dimethylsilyl(indenyl) 2 zirconium dichloride, rac-dimethylgermyl(indenyl) 2 zirconium dichloride, rac-dimethylsilyl(indenyl) 2 dimethylzirconium, rac-phenyl(vinvl)silyl(indenyl) 2 zirconium dichloride, ##STR27## rac-dimethylsilyl (2,4-dimethylcyclopentadienyl) 2 zirconium dichloride, racisopropylidene(idenyl) 2 zirconium dichloride, racdimethylsilyl (2-methyl-4,5,6,7-tetrahydro-1-indenyl) 2 zirconium dichloride, rac-ethylene(indenyl) 2 zirconium dichloride, rac-methylene(3-t-butyl-1-cyclopentadienyl) 2 zirconium dichloride and rac-dimethylsilyl(4,7-dimethyl-1-idenyl) 2 zirconium dichloride, or alternatively at least two zirconocenes of the formula I.

Claim 18

A process for the preparation of a monomodal, bimodal, or multimodal polyolefin having a molecular weight distribution M w /M n of ≧3.0, comprising: polymerizing an olefin of the formula R a CH═CHR b in which R a and R b are identical or different and are a hydrogen atom or an alkyl radical having 1 to 14 carbon atoms, or R a and R b , together with the atoms connecting them, form a ring, at a temperature of from -60° to 200° C., in suspension or in the gas phase, in the presence of a catalyst comprising a zirconocene component and an aluminoxane component, said aluminoxane component comprising an aluminoxane of the formula ##STR23## for the linear type or of the formula (III) ##STR24## for the cyclic type, where, in the formulae II and III, the radicals R are identical or different and are a C 1 -C 6 -alkyl group, a C 1 -C 6 -fluoroalkyl group, a C 6 -C 18 -aryl group, a C 1 -C 6 -fluoroaryl group or hydrogen, and n' is a number from 0 to 50, said aluminoxane component optionally containing a compound of the formula AlR 3 ; said zirconocene component comprising at least one zirconocene of the formula I ##STR25## in which R 1 and R 2 are identical or different and are a hydrogen atom, a C 1 -C 10 -alkyl group, a C 1 -C 10 -alkoxy group, a C 6 -C 10 -aryl group, a C 6 -C 10 -aryloxy group, a C 2 -C 10 -alkenyl group, a C 7 -C 40 -arylalkyl group, a C 7 -C 40 -alkylaryl group, a C 8 -C 40 -arylalkenyl group or a halogen atom, R 3 and R 4 are identical or different and are a hydrogen atom, a halogen atom, a C 1 -C 10 -alkyl group, which is optionally halogenated, a C 6 -C 10 -aryl group, or a --NR 2 10 , --SR 10 , --OSiR 3 10 , SiR 3 10 or --PR 2 10 radical, in which R 10 is a halogen atom, a C 1 -C 10 -alkyl group or a C 6 -C 10 -aryl group, R 5 and R 6 are identical or different and are as defined for R 3 and R 4 , with the proviso that R 5 and R 6 are not hydrogen, R 7 is ##STR26## ═BR 11 , ═AlR 11 , --Ge--, --Sn, --O--, --S--, ═SO, ═SO 2 , ═NR 11 , ═CO, ═PR 11 or ═P(O)R 11 , where R 11 , R 12 and R 13 are identical or different and are a hydrogen atom, a halogen atom, a C 1 -C 10 -alkyl group, a C 1 -C 10 -fluoroalkyl group, a C 6 -C 10 -aryl group, a C 6 -C 10 -fluoroaryl group, a C 1 -C 10 -alkoxy group, a C 2 -C 10 -alkenyl group, a C 7 -C 40 -arylalkyl group, a C 8 -C 40 -arylalkenyl group or a C 7 -C 40 -alkylaryl group, or R 11 and R 12 or R 11 and R 13 , together with the atoms connecting them, in each case form ring, and M 1 is silicon, germanium or tin, R 8 and R 9 are identical or different and are as defined for R 11 , R 14 and R 15 are identical or different and are a monocyclic or polycyclic hydrocarbon radicals which can form a sandwich structure together with the zirconium atom, and m and n are identical or different and are zero, 1 or 2, where m plus n is zero, 1 or 2, and at least one of the following zirconocenes: rac-phenyl(methyl)silyl(indenyl) 2 zirconium dichloride, diphenylmethylene(9-fluorenyl) (cyclopentadienyl)zirconium dichloride, isopropylidene(9-fluorenyl) (cyclopentadienyl)zirconium dichloride, rac-dimethylsilyl (2,3,5-trimethyl-1-cyclopentadienyl) 2 zirconium dichloride, rac-dimethylsilyl(indenyl) 2 zirconium dichloride, rac-dimethylgermyl(indenyl) 2 zirconium dichloride, rac-dimethylsilyl(indenyl) 2 dimethylzirconium, rac-phenyl(vinvl)silyl(indenyl) 2 zirconium dichloride, ##STR27## rac-dimethylsilyl (2,4-dimethylcyclopentadienyl) 2 zirconium dichloride, racisopropylidene(idenyl) 2 zirconium dichloride, racdimethylsilyl (2-methyl-4,5,6,7-tetrahydro-1-indenyl) 2 zirconium dichloride, rac-ethylene(indenyl) 2 zirconium dichloride, rac-methylene(3-t-butyl-1-cyclopentadienyl) 2 zirconium dichloride and rac-dimethylsilyl(4,7-dimethyl-1-idenyl) 2 zirconium dichloride, or alternatively at least two zirconocenes of the formula I.

Claim 19

The process as claimed in claim 15, wherein propylene is polymerized, alone or in combination with ethylene.

Claim 20

A process for the preparation of a monomodal, bimodal, or multimodal polyolefin having a molecular weight distribution M w M n of ≧3.0, comprising: polymerizing an olefin of the formula R a CH═CHR b in which R a and R b are identical or different and are a hydrogen atom or an alkyl radical having 1 to 14 carbon atoms, or R a and R b , together with the atoms connecting them, form a ring, at a temperature of from -60° to 200° C., in suspension or in the gas phase, in the presence of a catalyst comprising a zirconocene component and an aluminoxane component, said aluminoxane component comprising an aluminoxane of the formula ##STR28## for the linear type or of the formula (III) ##STR29## for the cyclic type, where, in the formulae II and III, the radicals R are identical or different and are a C 1 -C 6 -alkyl group, a C 1 -C 6 -fluoroalkyl group, a C 6 -C 18 -aryl group, a C 1 -C 6 -fluoroaryl group or hydrogen, and N' is an integer from 0 to 50, said aluminoxane component optionally containing a compound of the formula AlR 3 ; said zirconocene component comprising at least one zirconocene of the formula I and at least one zirconocene of the formula Ia or alternatively at least 2 zirconocenes of the formula I ##STR30## in which R 1 and R 2 are identical or different and are a hydrogen atom, a C 1 -C 10 -alkyl group, a C 1 -C 10 -alkoxy group, a C 6 -C 10 -aryl group, a C 6 -C 10 -aryloxy group, a C 2 -C 10 -alkenyl group, a C 7 -C 40 -arylalkyl group, a C 7 -C 40 -alkylaryl group, a C 8 -C 40 -arylalkenyl group or a halogen atom, R 3 and R 4 are identical or different and are a hydrogen atom, a halogen atom, a C 1 -C 10 -alkyl group, which is optionally halogenated, a C 6 -C 10 -aryl group, or a --NR 2 10 , --SR 10 , --OSiR 3 10 , --SiR 3 10 or --PR 2 10 radical, in which R 10 is a halogen atom, a C 1 -C 10 -alkyl group or a C 6 -C 10 -aryl group, R 5 and R 6 are identical or different and are as defined for R 3 and R 4 , with the proviso that R 5 and R 6 are not hydrogen, R 7 is ##STR31## ═BR 11 , ═AlR 11 , --Ge--, --Sn, --O--, --S--, ═SO, ═SO 2 , ═NR 11 , ═CO, ═PR 11 or ═P(O)R 11 , where R 11 , R 12 and R 13 are identical or different and are a hydrogen atom, a halogen atom, a C 1 -C 10 -alkyl group, a C 1 -C 10 -fluoroalkyl group, a C 6 -C 10 -aryl group, a C 6 -C 10 -fluoroaryl group, a C 1 -C 10 -alkoxy group, a C 2 -C 10 -alkenyl group, a C 7 -C 40 -arylalkyl group, a C 8 -C 40 -arylalkenyl group or a C 7 -C 40 -alkylaryl group, or R 11 and R 12 or R 11 and R 13 , together with the atoms connecting them, in each case form a ring, and M 1 is silicon, germanium or tin, R 8 and R 9 are identical or different and are as defined for R 11 , R 14 and R 15 are identical or different and are monocyclic or polycyclic hydrocarbon radicals which can form a sandwich structure together with the zirconium atom, and m and n are identical or different and are zero, 1 or 2, where m plus n is zero, 1 or 2.

Claim 21

A process for the preparation of a monomodal, bimodal, or multimodal polyolefin having a molecular weight distribution M w M n of ≧3.0, comprising: polymerizing an olefin of the formula R a CH═CHR b in which R a and R b are identical or different and are a hydrogen atom or an alkyl radical having 1 to 14 carbon atoms, or R a and R b , together with the atoms connecting them, form a ring, at a temperature of from -60° to 200° C., in suspension or in the gas phase, in the presence of a catalyst comprising a zirconocene component and an aluminoxane component, said aluminoxane component comprising an aluminoxane of the formula ##STR28## for the linear type or of the formula (III) ##STR29## for the cyclic type, where, in the formulae II and III, the radicals R are identical or different and are a C 1 -C 6 -alkyl group, a C 1 -C 6 -fluoroalkyl group, a C 6 -C 18 -aryl group, a C 1 -C 6 -fluoroaryl group or hydrogen, and N' is an integer from 0 to 50, said aluminoxane component optionally containing a compound of the formula AlR 3 ; said zirconocene component comprising at least one zirconocene of the formula I and at least one zirconocene of the formula Ia or alternatively at least 2 zirconocenes of the formula I ##STR30## in which R 1 and R 2 are identical or different and are a hydrogen atom, a C 1 -C 10 -alkyl group, a C 1 -C 10 -alkoxy group, a C 6 -C 10 -aryl group, a C 6 -C 10 -aryloxy group, a C 2 -C 10 -alkenyl group, a C 7 -C 40 -arylalkyl group, a C 7 -C 40 -alkylaryl group, a C 8 -C 40 -arylalkenyl group or a halogen atom, R 3 and R 4 are identical or different and are a hydrogen atom, a halogen atom, a C 1 -C 10 -alkyl group, which is optionally halogenated, a C 6 -C 10 -aryl group, or a --NR 2 10 , --SR 10 , --OSiR 3 10 , --SiR 3 10 or --PR 2 10 radical, in which R 10 is a halogen atom, a C 1 -C 10 -alkyl group or a C 6 -C 10 -aryl group, R 5 and R 6 are identical or different and are as defined for R 3 and R 4 , with the proviso that R 5 and R 6 are not hydrogen, R 7 is ##STR31## ═BR 11 , ═AlR 11 , --Ge--, --Sn, --O--, --S--, ═SO, ═SO 2 , ═NR 11 , ═CO, ═PR 11 or ═P(O)R 11 , where R 11 , R 12 and R 13 are identical or different and are a hydrogen atom, a halogen atom, a C 1 -C 10 -alkyl group, a C 1 -C 10 -fluoroalkyl group, a C 6 -C 10 -aryl group, a C 6 -C 10 -fluoroaryl group, a C 1 -C 10 -alkoxy group, a C 2 -C 10 -alkenyl group, a C 7 -C 40 -arylalkyl group, a C 8 -C 40 -arylalkenyl group or a C 7 -C 40 -alkylaryl group, or R 11 and R 12 or R 11 and R 13 , together with the atoms connecting them, in each case form a ring, and M 1 is silicon, germanium or tin, R 8 and R 9 are identical or different and are as defined for R 11 , R 14 and R 15 are identical or different and are monocyclic or polycyclic hydrocarbon radicals which can form a sandwich structure together with the zirconium atom, and m and n are identical or different and are zero, 1 or 2, where m plus n is zero, 1 or 2.