Functional fluid with borated epoxides, carboxylic solubilizers, zinc

Abstract

A multipurpose functional fluid is disclosed which is comprised of a major amount of a hydrocarbon oil and a minor amount, sufficient to improve characteristics of the fluid of a novel additive. The additive is comprised of a calcium salt complex, a group II metal dithiophosphate salt, a borated epoxide and a carboxylic solubilizer. The calcium salt is preferably in the form of an overbased calcium sulfonate salt, the antiwear agent is preferably in the form of a zinc dithiophosphate salt, the borated epoxide is preferably the reaction product of boric acid and a 16 carbon 1,2 epoxide and the carboxylic solubilizer is preferably in the form of a reaction product of an acylating agent containing a substituted hydrocarbyl-based substituent containing about 12 to 500 carbon atoms. Other components such as viscosity improvers and antifoaming agent are generally present in the fluid. The resulting fluid has improved low temperature fluidity and filterability, improved EP/antiwear performance, excellent friction improving properties, antichatter capability as well as being capable of passing hydraulic/transmission tests, power steering and brake capacity tests. These features are maintained simultaneously without harming other desirable performance characteristics of the fluid. The EP/antiwear performance characteristics are maintained concurrently with the anticorrosion characteristics and transmission performance capabilities. The improved water tolerance is maintained concurrently with the improved EP performance characteristics.