Lubricating oil made with synthetic base stocks (and not from mineral oil). These have much longer life and they don’t form tar like sticky compound when overheated or prolonged use as compared to mineral based lubricants.
Synthetic lubricants are composed of oil components that have been manufactured synthetically by reaction of a few well-defined chemical compounds (although often petroleum-based) rather than refined from existing petroleum crudes or vegetable oils.
Nevertheless, they are used with good success in applications with extremely high or low temperatures, where fire protection is required, or where very high speeds or high wear rates are encountered. The user must be careful when selecting these lubricants since some of them remove paint and attack rubber seals. The new synthesized hydrocarbons (SHC) have many desirable features such as compatibility with mineral oils and excellent high and low temperature properties. They are excellent selections when EP lubricants along with high temperature operation are required.