Improving the performance of synthetic base fluids with additives

Because of their improved performance characteristics over mineral oil based lubricants, partly and fully synthetic fluids are being used more open, the main types of synthetic base fluids being esters and polyalphaolefins (PAOs). The response of additives, such as anti-oxidants, anti-wear additives and viscosity index improvers, to mineral oil, eslers or PAOs will obviously differ. This paper reports an attempt to find the most effective types of such additives for esters and PAOs, in order to optimize lubricant performance. PAOs have deficiencies in terms of a number of peformance characteristics, particularly with respect to additive solubility, and they are thus blended with esters to improve these properties.