OXIDATIVE STABILITY AND ANTIWEAR PROPERTIES OF HIGH OLEIC VEGETABLE-OILS

Environmental concerns resulted in the utilization of vegetable oils a s a possible replacement of mineral oil basestocks. Their low oxidativ e stability is often a major concern. Data from the Klaus Penn State m icroreactor test on steel surfaces at 225 degrees C demonstrate that u ninhibited high oleic vegetable oils are much poorer in oxidative stab ility than neat mineral oils. Nevertheless, they show an advantage of low volatility. The possibility to dramatically inhibit deposit format ion in high oleic sunflower oil using 1% wt. of proprietary antioxidan t is demonstrated, resulting in oxidative stability comparable to 10W3 0 SG-grade commercial crankcase lubricant. Addition of ZDDP reduces th e effect of the antioxidant but greatly improves antiwear properties o f the fluid, as demonstrated by the four-ball wear test. Neat high ole ic sunflower oil shows better lubricity than neat mineral oil and its formulation with the antioxidant and ZDDP is superior to commercial cr ankcase lubricant in antiwear properties.