Synthetic Lubricants
Synthetic lubricants are lubricants produced by chemical synthesis
rather than by extraction or refinement of petroleum in order to produce
a compound that has planned and predictable properties. Within the auto
industry synthetic lubricants are typically used as motor oils in
gasoline or diesel engines, however other applications of synthetic
lubricants include use as food grade and high temperature lubricants, as
well as for gear, bearing, air compressor, blower and vacuum pump
lubrication.
Synthetic lubricants can offer numerous advantages over petroleum-based lubricants, commonly referred to as organic lubricants, including increased shear stability, reduced flammability, high oxidation resistance, decreased loss due to evaporation and enhanced mechanical and chemical properties. However, synthetic lubricants also have some disadvantages when compared to organic lubricants, such as potential problems with decomposition in industrial applications as well as compatibility issues with certain materials. Synthetic lubricants are most widely used in the automotive industry, in addition to use in the aerospace, marine, medical, industrial, HVAC, commercial and textile. Some dry lubricants, such as boron nitride and tungsten sulfide are synthetic, and synthetic lubricating grease is often used in the food industry as food grade lubricant for meat slicing machines and such. Food grade lubricants are particularly important synthetic lubricants, since they must be effective as lubricants as well as safe to digest incase they come in contact with food. Without synthetic lubes, it would be expensive and difficult to keep food processing machines well maintained.
The majority of synthetic lubricants are formed from one of five different bases. These bases include glycol, esters, polyalphaolefin, fluorinated lubricants and silicone, each of which is used for particular properties that offer advantages for specific applications. For instance, esters are chemical compounds composed of an oxoacid combined with a hydroxyl group. Ester-based synthetic lubricants have excellent heat-resistant properties and are used as high temp lubricants. The chemical compound glycol contains two hydroxyl groups and is also referred to as diol. Glycol-based synthetic lubricants offer increased lubricity due to glycol’s high polarity and as a result, have extremely high film strength. Polyalphaolefin is a polymer made from olefins and is also referred to as polyalkylene. Polyalphaolefin-based lubricants are ideal as multi-purpose lubricants because of their numerous advantages including thermal stability, high natural lubricity, hydrolytic stability and low volatility. There are three classes of fluorinated lubricants: chlorofluorocarbons, perfluoroalkylpolyethers and fluorosilicones. Fluorinated lubricants are expensive, but offer excellent chemical inertness that makes them worth the cost in many industrial applications. Lastly, silicone lubricants provide moisture protection that allows them to also function as sealants and are highly popular in the automotive industry.