US Patent 7989565 Polyolefins

Process for making a copolymer by copolymerising (1) ethylene with (2) at least one comonomer selected from aliphatic C3-C20 alpha-olefins and (3) 5-ethylidene-2-norbornene, including contacting the monomer with a catalyst comprising a transition metal compound having the following Formula A, and an activating quantity of a suitable activator of the formula shown herein, wherein Z comprises a five-membered heterocyclic group, the five membered heterocyclic group containing at least one carbon atom, at least one nitrogen atom and at least one other hetero atom selected from nitrogen, sulphur and oxygen, the remaining atoms in the ring being selected from nitrogen and carbon; M is a metal from Group 3 to 11 of the Periodic Table or a lanthanide metal; E1 and E2 are divalent groups independently selected from (i) aliphatic, hydrocarbon, (ii) alicyclic hydrocarbon, (iii) aromatic hydrocarbon, (iv) alkyl substituted aromatic hydrocarbon, (v) heterocyclic groups and (vi) heterosubstituted derivatives of said groups (i) to (v); D1 and D2 are donor atoms or groups; X is an anionic group, L is a neutral donor group; n=m=zero or 1; y and z are independently zero or integers such that the number of X and L groups satisfy the valency and oxidation state of the metal M.