Plant-oil-based lubricants and hydraulic fluids

It is estimated that, at present, approximately 50% of all lubricants sold worldwide end up in the environment via total loss applications, volatility, spills or accidents. More than 95% of these materials are currently mineral oil based. In view of their high ecotoxicity and low biodegradability, mineral oil-based lubricants constitute a considerable threat to the environment. In contrast, most lubricants and hydraulic fluids based on plant oils are rapidly and completely biodegradable and are of low ecotoxicity; moreover, lubricants based on plant oils display excellent tribological properties and generally have very high viscosity indices and flashpoints. However, in order to compete with mineral-oil-based products, some of their inherent disadvantages must be corrected, such as their sensitivity to hydrolysis and oxidative attack, and their behaviour at low temperatures. Various methods to improve the undesirable properties of native plant oils will be discussed. In parallel, government regulations that encourage or enforce the use of bio-based fluids, at least in ecologically sensitive areas, will help to increase their market share. Using the numerous possibilities for selective breeding and/or chemical improvement of the double bond systems of natural fatty acids by increased R&D, the major obstacles regarding the use of plant-based raw materials for the production of lubricant base fluids can be overcome and bio-based fluids should expect a future with increasing market shares.