Borated overbased sulfonates for improved gear performance in functional fluids

摘要

A functional fluid composition having improved gear performance comprises an oil of lubricating viscosity, and added thereto (a) an alkali or alkaline earth metal salt complex in the form of borated and/or non-borated salts; (b) an EP/antiwear agent comprising a mixture of zinc salts of dialkylphosphorodithioic acid and 2-ethylhexanoic acid heated with triphenyl phosphite or an olefin; and (c) a borated epoxide. The oil of lubricating viscosity has a kinematic viscosity of at least 4 cSt and 100 DEG C and a -40 DEG C Brookfield viscosity of less than 20,000.