Synthesis of branched polyethylene fluids for use in lubricant compositions

Abstract

The novel synthetic polyethylene fluids of the present invention are characterized by high viscosity indices (about 94-151 VI), low pour points (about -60 to -10.degree. C.), and a kinematic viscosity of about 6 to 28 cSt KV at 100.degree. C. The product compositions comprise polymers having a molecular weight of from about 300 to 30,000 and a high branching index of 151 to 586 branches per 1000 CH.sub.2 groups, or BI=0.18-0.40, wherein the polymer is substantially free of methyl branches. Highly-branched polyethylene fluids that have less than 5 methyl branches per 1000 CH.sub.2 groups are prepared by polymerizing ethylene in the presence of a catalyst system consisting of [C] and [B], wherein [C] is a catalyst having the empirical formula MX.sub.4 and [B] is a co-catalyst having the empirical formula R.sub.n AlX.sub.3-n, where M is a Group IVB transition metal, X is a halogen anion, R is a C.sub.1 -C.sub.20 alkyl group, and n is 1-2, in the presence of a promoter, wherein the promoter is selected from the group consisting of hydrogen or a Lewis acid such as, for example, FeCl.sub.3, AlCl.sub.3, or mixtures thereof.

Dependencies are inferred from the claim text.