prov:value
| - The process as claimed in claim 1, wherein the metallocene is a compound of the formula Ia ##STR10## in which R1 and R2 have the meaning given in claim 1 and R5, R6, R7, R8, R9 and R10 are identical or different and are a hydrogen atom, a halogen atom, a C1 -C10 -alkyl group, a C6 -C10 -aryl group, a C1 -C10 -alkoxy group or a --NR16 2, --SR16, --OSiR16 3, --SiR16 3 or --PR16 2 radical, in which R
|