Patent ID: 7202315

Claim:
A process for homopolymerizing ethylene comprising contacting under polymerization conditions, ethylene with a catalyst system obtained by contacting: A) a bis amido compound of formula (I) wherein Ti is titanium; N is a trivalent nitrogen atom; Y is equal to or different from each other, and is selected from the group consisting of Si, Ge and Sn; X is equal to or different from each other, and is selected from the group consisting of hydrogen, halogen, linear or branched, saturated or unsaturated C 1 –C 20 alkyl, C 1 –C 20 alkoxyl, C 3 –C 20 cycloalkyl, C 6 –C 20 aryl, C 6 –C 20 aryloxyl, C 7 –C 20 alkylaryl and C 7 –C 20 arylalkyl radicals, optionally containing one or more Si, Ge, O, S, P, B or N atoms, or X forms a ring having from 4 to 8 members; R 1 , R 2 , R 3 , R 4 , R 5 and R 6 are equal to or different from each other, and are selected from the group consisting of hydrogen, Si(R 7 ) 3 , linear or branched, saturated or unsaturated C 1 –C 20 alkyl, C 3 –C 20 cycloalkyl, C 6 –C 20 aryl, C 7 –C 20 alkylaryl and C 7 –C 20 arylalkyl radicals, optionally containing one or more Si, Ge, O, S, P, B or N atoms, or two or four substituents selected from the group consisting of R 1 , R 2 , R 3 , R 4 , R 5 and R 6 are linked to two vicinal atoms and form one or two rings having from 4 to 8 members; R 7 are equal to or different from each other, and are linear or branched, saturated or unsaturated C 1 –C 10 alkyl, C 3 –C 10 cycloalkyl, C 6 –C 15 aryl, C 7 –C 15 alkylaryl or C 7 –C 15 arylalkyl radicals; Q is a neutral Lewis base; and m is an integer ranging from 0 to 2; the bis-amido compound optionally being present in a dimer form; B) one or more activating cocatalysts selected from i) compounds of formula U + Z − , wherein U + is a cation that reacts irreversibly with X, and Z − is a compatible non-coordinating anion comprising at least one boron atom; and ii) neutral, strongly Lewis acidic compounds comprising at least one boron atom or combinations thereof; C) optionally when X is halogen, one or more aluminum alkyls or alumoxanes, wherein the process produces an ethylene homopolymer with a long chain branch content higher than 0.05 per 1000 carbon atoms.