Bimetallic metallocene alumoxane catalyst system and its use in the preparation of ethylene-alpha olefin and ethylene-alpha olefin-non-conjugated diolefin elastomers

Claim 1

A process for producing an ethylene-alpha-olefin elastomeric copolymer comprising: (i) adding ethylene and an alpha-olefin monomer to a reaction vessel in amounts and Under pressure sufficient to maintain the desired ethylene-alpha-olefin weight ratio in the liquid phase in the reaction vessel; and (ii) adding to the mixture of monomers a catalyst system selected from the group consisting of 1,9-(1,9-disila -1,1,9,9-tetramethylnonylene)-1,1 1 -di[bis(cyclopentadienyl) zirconium dichloride], 1,10-(1,10-disila-1,1,10,10-tetramethyldecylene)-1,1 1 -di[bis(cyclopentadienyl) zirconium dichloride], 1,12-(1,12-disila-1,1,12,12-tetramethyldodecylene)-1,1 1 -di[bis(cyclopentadienyl) zirconium dichloride], [1,7-disila-1,7-dimethyl-heptadiylidene]-1,1 1 ,1 11 ,1 111 -di[bis(cyclopentadienyl) zirconium dichloride], [1,8-disila-1,8-dimethyl-octadiylidene]-1,1 1 ,1 111 ,1 111 -di[bis(cyclopentadienyl) zirconium dichloride], [1,9-disila-1,9-dimethyl-nonadiylidene]-1,1 1 , 1 11 , 1 111 di[bis(cyclopentadienyl) zirconium dichloride], [1,10-disila-1,10-dimethyl-decadiyliden]-1,1 1 , 1 11 , 1 111 -di-[bis(cyclopentadienyl) zirconium dichloride] and [1,12-disila-1,12-dimethyl-dodecadiylidene]-1,1 1 , 1 11 , 1 111 -di[bis(cyclopentadienyl) zirconium dichloride]; and an alumoxane; (iii) reacting the mixture for a time sufficient to permit copolymerization of said ethylene and alpha-olefin to an elastomeric copolymer, and (iv) recovering the elastomeric copolymer.