Lube-Tech PUBLISHED BY LUBE: THE EUROPEAN LUBRICANTS INDUSTRY MAGAZINE
Edward Casserly, Ph.D., Timothy Langlais, MBA, and Staci P. Springer, MBA, ERGON REFINING, Inc., Jackson, MS
in cooperation with Anoop Kumar, Ph.D. and Bill Mallory, Royal Manufacturing Company, Tulsa, OK
No.115 page 1
The Effect of Base Oils on Thickening and Physical Properties of Lubricating Greases
This paper examines the effects of naphthenic, paraffinic, and synthetic (polyalphaolefin or PAO) base oils on the thickening capabilities of lithium 12-hydroxystearate (Li 12-HSA), lithium complex (Li complex), aluminum complex (Al complex), clay base, and calcium sulfonate complex (Ca sulfonate) greases and their associated physical properties.
Introduction Lubricating greases consist of base oil (50-98%), thickener (2-50%), and various additives (0-10%) such as antioxidants, corrosion inhibitors, antiwear, and extreme pressure additives. Grease may be used to lubricate bearings and gears (enclosed and open), provide a protective coating, or as a parting agent and drawing compound in casting. Grease is used instead of oil in applications where retention is important, less frequent application is required, to seal out dirt and contaminants, and to protect metals from corrosion.
32 LUBE MAGAZINE NO.144 APRIL 2018
Accordingly, manufacturers measure several unique physical properties of grease: pumpability, dropping point, mechanical stability, and oil separation. In general, for most soap-thickened greases, base fluid viscosity and grease consistency are independent properties of a lubricating grease. The viscosity of the base fluid is determined by the base stock viscosity as well as the effect of some additives. The consistency of a grease is determined by the type and concentration of the thickener in the product.
There are three basic types of hydrocarbon base oils used in grease today. These are naphthenic oils, paraffinic oils, and synthetic isoparaffinic hydrocarbons. The paraffinic oils can be further subdivided into Group I, Group II, and Group III base oils. The synthetic isoparaffinic hydrocarbons consist of Group IV polyalphaolefins (PAO) which are typically oligomers of 1-decene and are the most
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