Boron based Lewis acids having fluorinated aryl substituents are known to be capable of activating transition metal compounds into olefin polymerization catalysts. Trisperfluorophenylborane is taught in EP 0 520 732 to be capable of abstracting a ligand for certain cyclopentadienyl derivatives of transition metals while providing a stabilizing, compatible noncoordinating anion. The term "noncoordinating anion" is now accepted terminology in the field of olefin polymerization, both by coordination or insertion polymerization and carbocationic polymerization. See, for example, EP 0 277 004, U.S. Pat. No. 5,198,401, and Baird, Michael C., et al, J Am. Chem. Soc. 1994, 116, 6435-6436, and U.S. Pat. No. 5,668,234. The noncoordinating anions are described to function as electronic stabilizing cocatalysts, or counterions, for cationic metallocene complexes which are active for olefin polymerization. The term noncoordinating anion as used here applies both to truly noncoordinating anions and coordinating anions that are at most weakly coordinated to the cationic complex so as to be labile to replacement by olefinically or acetylenically unsaturated monomers at the insertion site.
Organoaluminum compounds are known to be useful with metallocene based transition metal cationic catalysts stabilized with noncoordinating anions, both for catalyst poison inhibition and for alkylation of metallocene dihalide compounds, see WO 91/14713 and EP 0 500 944. See also WO93/14132 where alumoxane compounds are said to be useful for inhibiting catalyst poisons in the presence of cationic, cyclopentadienyl Group 4 complexes activated by tris(perfluorophenyl)boron.
U.S. Pat. No. 5,296,433 teaches the utility in olefin polymerization of borane complexes comprising tris(pentafluorophenyl)borane and complexing compounds such as water, alcohols, mercaptans, silanols, and oximes. These complexes are said to render Group IVB organometallic catalysts based on them soluble in olefin monomer such that higher molecular weight polymers can be made with resulting lower levels of catalyst residue. WO 96/26967 addresses similar tris(pentafluorophenyl)borane complexes and their use with Group IVB organometallic compounds to make rubbery polypropylene homopolymers and copolymers. Polymerization examples are presented where trialkyl aluminum compounds were combined with the reaction product of metallocene compounds with the described complexes. This document also teaches that tris(pentafluorophenyl)-borane forms 1:1 complexes with Lewis bases such as ether, amines and phosphines but states that no uses for such donor-acceptor complexes have been taught.
USPTO Backgrounds
USPTO Backgrounds