Thermally stable antifoam agent and methods for use in functional fluids

摘要

A functional fluid contains conventional additives in addition to an antifoam composition. The antifoam compositions contain perfluoropolyether compounds (PFPE). An exemplary functional fluid is an engine oil and engines containing such new engine oil as per the invention exhibit reduced foaming and improved performance. A method of treating the engines comprises adding to the lubricating composition in the sump a top treat composition comprising an antifoam composition of the invention.