Process and catalyst for producing reactor blend polyolefins

Claim 2

A catalyst system suitable for use in the production of reactor blend polymers comprising (a) at least two different metallocenes, being organometallic coordination compounds which are derivatives of mono, di or tricyclopentadienyls with Group 4b, 5b or 6b transition metal, the molar ratio of the metallocenes being between 100:1 and 1:100; and (b) an alumoxane.

Claim 3

A catalyst system according to claim 1 wherein the molar ratio of the metallocenes is between 10:1 and 1:10.

Claim 4

A catalyst system according to either of claims 1 and 2 wherein the metallocenes are represented by the general formula: or wherein (C 5 R' m ) is a cyclopentadienyl or substituted cyclopentadienyl, each R' which can be the same or different is hydrogen or a hydrocarbyl radical or two R' substituents together form a fused C4-Cfi ring, R" is a C l -C 4 alkylene radical, a dialkyl germanium or silicone, or an alkyl phosphine or amine radical bridging two (C 5 R' m ) rings, Q is a hydrocarbon radical or halogen and can be the same or different, Q' is an alkylidene radical having from 1 to 20 carbon atoms, M is a transition metal of Group 4b, 5b or 6b, s is 0 or 1, p is 0, 1 or 2; s is 0 when p is 0; m is 4 when s is 1; and m is 5 when s is 0.

Claim 5

A catalyst system according to claim 3 wherein Q is methyl, phenyl or chloride.

Claim 6

A catalyst system according to either of claims 3 and 4 wherein M is zirconium or titanium.

Claim 7

A catalyst system according to claim 5 comprising at least two zirconocenes.

Claim 8

A catalyst system according to claim 6 comprising bis(methylcyclopentadienyl) zirconium dichloride and bis(pentamethylcyclopentadienyl) zirconium dichloride.

Claim 9

A catalyst system according to claim 5 comprising at least one titanocene and one zirconocene.

Claim 10

A process for producing a reactor blend comprising polymerising ethylene and at least one alpha-olefin simultaneously in the presence of the catalyst system according to any of the preceding claims, the metallocenes having different reactivities with respect to the monomers employed.

Claim 11

A process according to claim 9 wherein the reactor blend comprises a blend of polyethylene and ethylene-propylene copolymer.

Claim 12

A process according to claim 10 wherein the polyethylene is LLDPE or HDPE.

Claim 13

A process according to claim 9 wherein the reactor blend comprises HDPE/EPR, LLDPE/EPR, HDPE/LLDPE or HDPE/LLDPE/EPR.