TABLE OF CONTENTS A lubricant usually has a base fluid. The base fluid is generally of petroleum origin, combined with additive chemicals that enhance the various desirable properties for a base fluid. Base fluids are essentially obtained from two main sources. One is the refining of petroleum crude oil, and the second is the synthesis of relatively pure compounds with properties that are desirable for lubricants.
The general principles of lubricant base oil manufacture involve a series of steps to improve certain desirable lubricant properties, such as:
Viscosity index
Oxidation resistance
Heat resistance
Low-temperature fluidity.
Starting with petroleum crude oil, the typical process for making lubricant base oil involves:
Separation of lighter boiling materials such as gasoline, jet fuel, diesel, etc.
Removal of impurities that include aromatics and polar compounds
Distillation to give desired base oil viscosity grades
Dewaxing to improve low-temperature fluidity
Finishing to improve oxidation and heat stability.
Another source of lubricant base fluids is synthetic of origin. A suitable definition for a synthetic material is: A product prepared by chemical reaction of lower molecular weight materials to produce a fluid of higher molecular weight designed to provide certain predictable properties.
This is in contrast with refined petroleum oils, which are composed of many compounds of varying chemical composition, depending on the refining method and the crude stock source.
The three most common types of synthetic base oils are:
Polyalpholefins
Organic esters
Polyglycols.
Other synthetic fluids find niche uses in very specialized...
