Haze free oil additive compositions containing polymeric viscosity index improver and process for producing said compositions

Claim 1

A process of decreasing haze in a composition comprising: a major amount of hydrocarbon lubricating oil; in the range of about 5 to 30 wt. %, based upon the total weight of said composition, of an oil-soluble viscosity index improver polymer which consists essentially of about 30 to 80 wt. % ethylene and propylene, said polymer being formed by a Ziegler-Natta polymerization, said polymer having a M n in the range from 700 to 500,000 and a M w /M n ratio of less than 10; and a haze forming amount, but less than 1 wt. %, based on the total weight of said composition, of an oil insoluble, haze forming material resulting from the manufacture of said polymer, which material is a disassociable metal salt of a weak organic acid having a pK of more than about 3.8, and wherein said metal is selected from the class consisting of alkaline earth metal, zinc, sodium, potassium, aluminum, vanadium, chromium, iron, manganese, cobalt, nickel, cadmium, lead, bismuth and antimony; which process comprises adding to said composition about 0.1 to about 2.5 equivalents, per equivalent of metal of said haze forming material, of an oil soluble hydrocarbyl substituted strong acid containing a hydrogen disassociating moiety and having a pK of less than about 2.5, and reacting for about 0.1 to about 20 hours at room temperature to about 250° C. said strong acid with said haze forming material to thereby decrease haze by converting said haze forming material either to an oil soluble weak acid or a volatile product, while converting the metal into an oil soluble strong acid metal salt and/or ionic complex of said strong acid, wherein said strong acid is selected from the group consisting of maleic acid, malonic acid, phosphoric acid, thiophosphoric acids, phosphonic acid, thiophosphonic acids, phosphinic acid, thiophosphinic acids, sulfonic acid, sulfuric acid, and alpha-substituted halo- or nitro- or nitrilo-carboxylic acids; and wherein the oil solubilizing hydrocarbyl group or groups of said strong acid contain from about 6 to about 40 carbon atoms.