ABSTRACT
Historically, the base stocks for functional fluids have been derived from petroleum. Synthetics, on the other hand, are products manufactured by chemical synthesis. The development of synthetic functional fluids can be traced back over 50 years [1]. The initial impetus was the military need for fluids with high-performance characteristics. German
shortages of petroleum during World War II also spurred development of synthetics. Until the mid-1970s, however, synthetics were used only in those applications where the required performance characteristics could not be met by petroleum-based products (i.e., mineral oils). The large cost differential virtually prohibited the use of synthetics in any application adequately served by mineral oils.
