However, a good complex will have a significantly more stable structure and as the temperature approaches 300C may not show an apparent loss of structure. In short, greases have mineral paraffinic base oils as a liquid lubricant. The penetration range at 77F (25C) is 265 to 295. Whereas table 2 is a synthetic PAO formulation. Silicone grease is silicone oil based together with inert fillers thickened with a lithium soap. lithium 12-hydroxystearate grease is probably the best multipurpose grease ever developed. . # 3 # A lithium soap having the formula ##STR2## wherein R represents a member selected from the group consisting of hydrogen, hydroxy, a double bond with the adjacent R and mixtures thereof, n is an integer from 0 to 6, m is an integer from 0 to 6, n+m is an integer from 6 to 9, and R 1 and R 2 represents a member selected from the group . Lithium complex grease, the most popular in North America, is made with lithium hydroxide, 12 HSA, and azelaic acid. The portion of the grease that determines the compatibility is the thickener. Soaps are salts of fatty acidsthey are prepared by heating a fat with a strong base. Lithium soap is the thickener that turns the base oil into grease. But the use of 12HSA along with HCO (hydrogenated castor oil) is most preferred. manufacturing greases with lithium soap as thickener. Lithium soap complex. The heat resistance of a grease can be measured by a temperature sweep test using a controlled stress rheometer. In most cases, lithium soap-based greases offer so many advantages that the additional cost is easily offset by increased performance. MOLYKOTE 33 Extreme Low Temp Bearing Grease (Light) is a premium silicone-based lubricant formulated with a lithium-soap thickener for excellent long-term performance. Lithium-based greases are among the most commonly used greases today, as they offer multi-purpose properties, good low-temperature performance and mechanical stability, low oil bleed tendency, good pumpability and good long-term storage stability. Boom bust Boom. Mineral paraffinic base oils along with naphthenic are prevalent to manufacture greases. These observations may very. The main thickener used in grease is a metallic soap. In addition, you'll find a list of applications where these thickeners have been successful. If you provide more services, kindly contact me via the mentioned e-mail. In the actual reaction process, 12-hydroxystearic acid and stearic acid as thickeners cannot completely saponify with lithium hydroxide to form soap fibers. It offers excellent resistance to heat and water. Begin with understanding the components of grease and its properties. Composition / Chemistry: Lithium Complex or Soap Thickener. Water is still soluble in lithium hydroxide, but only in small amounts. At this time, modern lithium soap (thickener) consists of 12HSA (12-hydroxystearic acid, or triglycerides) with lithium hydroxide monohydrate in a base fluid. Other thickeners such as calcium and barium are more water resistant than lithium and lithium complex thickeners, but their negative qualities make them less desirable in a wide variety of applications. It is the most common soap used to stabilize and thicken lubricating greases. Lithium complex grease, the most popular in North America, is made with lithium hydroxide, 12 HSA, and azelaic acid. Copyright 2022 Redlist, LLC. Similarly, manufacturers use naphthenic base oils to achieve better thickening by soaps and low-temperature fluidity. 1. [Pg.905] Lithium greasescan be manufactured by continuous processin a heated tube reactor. Here base oil is available in 205 litres. The most common mixed soap grease is lithium/calcium as the lithium will improve the high temperature resistance of the resulting grease while the calcium improves the water washout and cost. Caltex Molytex EP 2 Lithium Grease offers further protection through the presence of rust and corrosion inhibitors and molybdenum disulfide solid lubricant. We use our own and third party cookies to personalize content and analyze web traffic. But due to the high price of silicon oil, it has limited use.Esters and PAO-based greases are only for demanding applications due to the very high cost of the synthetic base fluids. Non-soaps are split into two main categories. These thickener types have an advantage over simple soap because of better high-temperature properties. Over time, if the oil separates too much in storage, it may be impossible for the grease to be reconstituted for use. The penetration range at 77F (25C) is 265 to 295. Applications Many fats and fatty acids are suitable to make lithium soaps. 10. There are three types of soap-based thickeners: Simple soap Simple soap results from the reaction of one fatty acid, such as 12 hydroxy stearic acid (12 HSA), and a metallic hydroxide, such as lithium hydroxide. Shut off the heat and hold the batch at 200-210C (383-410F) for 15 minutes while mixing. [3] Use it in normal bearing applications. 3. More than 90% of all bearings have grease as a lubricant. The composition of the thickener is the mixture of lithium 12-hydroxyoctadecanoate and lithium stearate, and the molecular structure of lithium soap is shown in Fig. Thereis a wide variety of soap greases to choose from and they all have different physical properties where the application requirements dictate which soap is best. Add the initial base oil (40-60% of total base oil) to an open kettle, start heating and mixing. On average, polyurea greases can have a three to five times better life expectancy than lithium-based greases. So, lithium hydroxide-based thickeners have the same properties. Thanks. Lithium soap: 2 Low temperature performance Compatibility with plastics: PERMALUB CPL-501: Synthetic oil: Lithium soap . Table 1 is a lithium grease in mineral group I base oil. Lithium soap is the thickener that turns the base oil into grease. [2]. While they are worth a mention as they are the first modern greases, having been developed in the late 1800s, Calcium soap based greases are used less and less today. Lithium greases provide good lubricity and have great shear stability, thermal resistance and relatively low oil separation. Simple lithium soaps are often used in low-cost general-purpose greases and perform relatively well in most performance categories at moderate temperatures. For example, common grease additives areanti-corrosion,metal deactivators,antioxidants,and performance enhancement additives likeanti-wear propertiesand other characteristics. Types of Non-Soap Thickeners Complex soaps. The resulting grease carries unknown performance characteristics (load, temperature stability, shear, etc. You may ask yourself why the selection of a grease thickener is so important to your application. The different types of soap thickeners include lithium 12-hydroxy stearate soaps, lithium stearate soaps, calcium soaps, sodium soaps and aluminum soaps. These thickener types have an advantage over simple soap because of better high-temperature properties. The NLGI grease guide states a thickener is the solid particles which are relatively uniformly dispersed to form the structure of lubricating grease in which the liquid is held by surface tension and other physical forces.. When aluminum soap greases get too hot from bearing heated, they form stringy gels that cause sharp increases in torque and therefore additional work is required to turn a bearing. "Numerous types of grease thickeners are currently in use, each with its own pros and cons. -How does cooling rate affect grease properties? Suitable for automotive and industrial machines, plain/rolling elements bearings, marine, agricultural, mining, construction machinery, pumps, conveyors, elevators, chains, pulleys, cranes, shafts, wire ropes, and automotive applications, where good water resistance and good thermal stability are required. 1347613 [LMCG1/0.4 from SKF Group (The)] from RS Components, Ltd. GMW16601. The combination of sodium/calcium has also been used where the calcium improves the water resistance without lowering the operating temperature of the grease too much. Lithium 12-hydroxystearate is a fatty acid salt commonly known as a "lithium soap". Different thickener systems can react with each other to modify the physical and chemical structure resulting in the inability to hold or release the base oil. Invented in [], Calcium Soap Greases: Tallow (animal fat) based calcium greases were the earliest [], Lubricating grease consistency A grease consistency or penetration score indicates grease consistency []. Lithium grease remains stable in high temperature compare to Silicone grease. Available as an extreme pressure (EP) grease, which adds high load and anti-wear abilities. Examples of simple soap thickeners include lithium 12-hydroxystearate and calcium stearate. Introductory Guide to Acid Number Lubricant Analysis, Intro to Proper Journal Bearing Lubrication, Lubrication Management Practices to Improve Operations, How to Implement Operator-Driven Reliability, The Components of an Effective Lubrication Management Program, A high dropping point of 190-200C (374-392F), Depending on the base oil, a good low-temperature function. Premium Lithium Complex Grease . They offer excellent lubricity, shear stability, and thermal resistance. Copyright 2014-2021 Exxon Mobil Corporation. Lithium 12-hydroxy stearate greases are the most widely used soap greases. Product Name Base Oil Thickener Penetration Grade Characteristics; PERMALUB FIM-3J: Synthetic oil: Lithium soap: 2 . Lithium grease adheres particularly well to metal, is non-corrosive, may be used under heavy loads, and exhibits good temperature tolerance. Lithium hydroxide, Calcium hydroxide or Aluminium hydroxide which is why you will hear greases described as lithium grease, calcium grease and so on. All Rights Reserved, Understanding Grease Thickener Technologies Part 2: Soap-Based Thickeners. Lithium complex greases differed by having a higher dropping point, which allows the grease to work at higher temperatures. (Lithium soapthickens the oil.) Back in November 2017, the spot price for battery-grade lithium carbonate in China peaked at 175,000 yuan per tonne. Lithium soap greases resist shearing . In wet situations, excellent water resistance ensures the grease stays put and isnt washed or sprayed off, minimizing the need for frequent reapplication. Lithium Complex. So, it is best to compare lithium soap-based grease to those using other thickeners, such as sodium and calcium soap thickeners.
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