SOLVENT DEWAXING WAXY HYDROCARBON OIL DISTILLATES USING A COMBINATION POLY DI-ALKYL FUMARATE-VINYL ACETATE COPOLYMER HAVING PENDENT CARBON SIDE CHAIN LENGTH OF PREDOMINANTLY C.SUB.2.SUB.2 AND POLYALKYL(METH-)ACRYLATE POLYMER DEWAXING ACID

This invention relates to processes for solvent dewaxing waxy hydrocarbon oil distillates employing a dewaxing aid which dewaxing aid is a mixture of (a) poly(meth-)acrylate polymers and (b) polydialkylfumarate/vinyl acetate copolymers. The dewaxing aid mixture is selected from the group of mixtures consisting of a mixture of (a) poly(meth-)acrylate polymer which is an ester of a C10 to C22 aliphatic alcohol with acrylic or methacrylic acid and has a number average molecular weight greater than about 5,000 and (b) polydialkylfumarate/vinyl acetate copolymer wherein the pendent alkyl side chain group contains from 16-30 carbon atoms but is primarily i.e. >50% C22 (preferably behenyl), and the component (B) has a number average molecular weight of about 1,000 to 100,000, preferably about 5,000 to 50,000. The combination (a) plus (b) may be employed in a weight ratio within the range of from about 100/1 to 1/100, preferably about 8/1 to 1/4, more preferably about 8/1 to 1/1 most preferably about 3/1 a/b, and at an aid dose level ranging from about 0.01 to 1 wt.%, preferably between about 0.02 to 0.2 wt.% active ingredient. The solvent dewaxing of bright stocks can also be benefitted by using as a dewaxing aid a combination consisting of component B recited above and a component A which is a polymethacrylate copolymer having an average pendent carbon side chain length of predominantly i.e. >50% C16 and higher.