Compared with other alkali soaps in 1942, lithium-based grease has many improved properties compared with calcium-based and sodium-based greases based on lithium soap. Compared with sodium soap grease, they have better water resistance, better high temperature performance, excellent mechanical properties, shear resistance and good pumping ability. Although the manufacturing cost of lithium soap-based grease is higher than other types of grease, compared with sodium and calcium soap thickeners, lithium soap-based grease has many advantages, so the extra cost can be offset by improving its performance.
Lithium soap, especially 12- hydroxystearate lithium soap, has strong thickening ability for mineral oil or synthetic oil. Therefore, compared with calcium-sodium grease, lithium-based grease can reduce the thickening dose by about 1/3, and its service life can be more than doubled. Lithium-based grease, especially the grease thickened with 12- hydroxy lithium stearate soap, can be used for bearing lubrication of airplanes, automobiles, tanks, machine tools and various mechanical equipment by adding antioxidants, rust inhibitors and extreme pressure agents, which can replace calcium-based grease and sodium-based grease. General lithium-based grease (GB7324- 1994): It is divided into 1#, 2# and 3# according to the consistency grade. It has good water resistance, mechanical stability, corrosion resistance and oxidation stability, and is suitable for lubrication of friction parts such as rolling bearings and sliding bearings of various mechanical equipment with working temperature of -20 ~ 120℃. So what are the advantages of lithium-based grease?
1. Lithium composite grease is different from lithium-based grease.
Lithium composite grease has many characteristics of simple lithium soap grease, and has a high dropping point, so that the grease can be used at a higher temperature.
Second, a higher dropping point.
The dropping point of lithium composite grease is higher than that of simple lithium soap grease due to the existence of the second thickener component called complexing agent. Modern lithium composite grease usually uses bifunctional carboxylic acids with short chain length, such as azelaic acid or adipic acid. Compared with simple lithium soap thickeners, lithium salts of these substances usually exist in a significantly lower proportion. An alternative material used as complexing agent is boric acid. The use of this material will also lead to an increase in dropping points.
Third, shear resistance.
Mechanical stability, also known as shear stability, is the ability of grease to maintain consistency when subjected to mechanical shear force. Simple lithium-based grease has good shear resistance, and lithium composite grease also has good shear resistance. This characteristic makes simple lithium and lithium composite grease widely used in various fields.
Fourth, water resistance.
The water resistance of pure lithium and lithium composite grease is related to the solubility of thickener. The solubility of lithium hydroxide in water is limited (about 10%), and the thickener based on it also has a certain solubility. This provides good washing resistance and water absorption. Although other types of thickeners (calcium and barium) have better inherent water resistance than lithium and lithium composite thickeners, these products have disadvantages, which make them less ideal in many applications. In addition, adding a small amount of polymer additives can improve the water resistance of pure lithium and lithium composite grease.
Verb (abbreviation of verb) oil separation performance
The oil separation performance of lubricating grease is related to the lubricating ability and storage stability of products. Grease must release enough oil in the applied contact area (bearings, gears), and at the same time, it must not release too much oil during storage, otherwise the product will be unusable. If there is too much oil during storage, grease should not be mixed and reused.
After reading this article, do you know more about lithium-based grease? I hope everyone can get something after reading it.
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