ELASTOMER COMPATIBLE SEAL SWELL ADDITIVE FOR AUTOMATIC TRANSMISSION FLUIDS, POWER TRANSMISSION FLUIDS AND HYDRAULIC STEERING APPLICATIONS

摘要

ABSTRACT OF DISCLOSUREA fluid having a mineral lubricating oil base and containing the combinationof an oil-soluble tris (C8-C24 hydrocarbyl) phosphite ester and an oil-solubleC8-C24 hydrocarbyl substituted phenol, the weight ratio of said phosphite tosaid phenol ranging from about 4:1 to 1:4, preferably 3:1 to 1:3 wherebyelastomer compatibility of said fluid is enhanced. The phosphite ester-substituted phenol combination imparts to the fluid the property of maintainingthe chemical and physical properties of seals under oxidizing condition inautomatic transmissions, power transmissions and power steering systems andthereby improves retention of the fluid in these mechanical structures;preferably when at least an inhibitory amount of an anti-oxidant capable oftrapping free radicals at temperatures above 65°C., to 200°C. is present.