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Lithium Stearate and Lithium Grease Overview

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Update time : 2019-10-14 13:57:19
Overview

Lithium stearate, also known as lithium octadecanoic, has a white powdery form and is stable under average temperature and pressure. Insoluble in ethyl acetate. The water solubility is 0.09g/100ml, slightly soluble in water; the solubility in ethanol is 0.04g/100ml, somewhat dissolvable in ethanol. A colloid is formed in mineral oil. Melting point: 220.0-221.5 °C. Commonly used in stabilizers and lubricants. A medium-viscosity mineral or synthetic lubricating oil thickened by lithium stearate can be made into a lithium-based grease.

 
 

Performance Characteristics

(1) Grease thickened by lithium stearate, only two intersecting temperatures, the first intersecting temperature (from pseudo-gel state to gel state) is generally above 170 ° C, the second phase transition temperature ( That is, from the gel state to the sol state) usually above 200 ° C, therefore, when a suitable mineral oil is selected, it can be used at 120 ° C for a long time or 150 ° C for a short period of time.

(2) A grease thickened with lithium stearate can be seen by an electron microscope to form a double-stranded, entangled twisted ribbon, and thus has excellent mechanical stability.

(3) Determination of the heat of adsorption of alkanes by lithium 12-hydroxy stearate and lithium stearate by gas chromatography, and the binding strength of lithium 12-hydroxypalmitate and lithium stearate to the surface of soap fiber And the liquid phase bonding strength in the crystal lattice is relatively large, therefore, the lithium stearate thickened grease has better colloidal stability.

(4) The degree of solubility in water in the alkali metal is small, so the oil thickened with lithium stearate has excellent water resistance and can be used for wet and mechanical parts in contact with water.
 

 
 

Application

Lithium stearate soap has a strong thickening ability for mineral oil or synthetic oil. Therefore, compared with calcium-based grease, lithium-based grease can reduce the thickening dose by about 1/3, and the service life can be extended by one. More than double. Lithium-based oils, especially those formulated with lithium 12-hydroxy stearate soap, are added with antioxidants, rust inhibitors, and extreme pressure agents to become multi-effect long-life general-purpose greases. Calcium-based anti-grease and sodium-based grease for bearing lubrication in aircraft, automobiles, tanks, machine tools, and various mechanical equipment.

 

(I) Universal lithium grease

 

1 Introduction

The general-purpose lithium-based grease is made of a hard acid lithium soap thickened medium-viscosity mineral oil and is added with an anti-oxidation anti-rust additive.

2. Performance

(l) Has excellent resistance to water and rust. It can be used on wet and mechanical parts that come into contact with water.

(2) It has excellent mechanical stability and colloidal stability. Under high-speed mechanical shearing, the grease does not become thin or lost.

(3) Excellent heat resistance and a high dropping point. It can be used at more top temperature conditions.

3. Use

  Universal lithium grease is a long-life, multi-purpose oil that replaces calcium-based, sodium-based, and calcium-sodium-based lubricants and is a replacement for these greases. It has excellent water resistance, mechanical stability, rust resistance, and oxidation stability, and is widely used for lubrication of rolling bearings and sliding bearings and other friction parts of various automated equipment in a wide temperature range of -20 ° C ~ 120 ° C. Suitable for medium and medium speed mechanical equipment. Such as cars, tractor wheel bearings, small and medium-sized motors, pumps, and blowers. Also suitable for mining machinery, automobiles, tractor wheel bearings, large and medium engines, and other equipment.

4. Notes

(l) General-purpose lithium-based grease should not be packed in large containers to avoid oil precipitation. If there is a small amount of oil, it can be stirred or ground at room temperature and used.

(2) Do not mix with other lipids.

 

(II) Automotive, general-purpose lithium grease

 

l. Introduction

Automotive general-purpose lithium grease is made by thickening fatty acid soap with low-condensation point mineral oil and adding rust inhibitor and antioxidant.

2. Performance

(l) It has excellent high and low-temperature properties and can be used in a wide temperature range of -30 ° C ~ 120 ° C.

(2) It has excellent water resistance and rust resistance and can be used on wet and mechanical parts in contact with water.

(3) It has excellent mechanical stability, colloidal stability, oxidation stability, water resistance, and lubricity. Under the mechanical shearing action of high-speed operation, the grease will not deteriorate and lose, ensuring proper lubrication.

3. Use

Automotive general-purpose lithium grease is suitable for lubrication of friction parts such as automobile hub bearings, chassis, and water pump in the range of -30 °C~120 °C. It can also be used for the load wheels and guide wheel bearings of tanks. Compared with the currently used calcium-based fats and complex calcium-based greases, the oil change period is extended by two times, the wear is reduced, and the variety is simplified. Satisfying the use of cars from the cold zone to the tropics can reduce lubrication and maintenance costs by more than 40%.

4. Notes

(l) Wash the bearing when it is used. After drying, fill the grease into the inner raceway and the rolling element to ensure proper lubrication.

(2) The grease container should be kept clean and stored in a dry and dark place.

(3) After being activated, it should be tightly sealed to prevent impurities from entering, and the rabbits will affect the use effect.

 

(III) Synthetic lithium grease

 

l. Introduction

The synthetic lithium-based grease is made by thickening a medium viscosity mineral oil with lithium stearate and adding an antioxidant or the like. According to the penetration degree, it is divided into four grades: ZL-LH, ZL-2H, ZL-3H, and ZL-4H.

2. Performance

(l) It has a certain degree of water resistance and can be used on wet and mechanical parts in contact with water.

(2) It has excellent mechanical stability.

 (3) High dropping point and excellent heat resistance.

3. Use

Synthetic lithium grease is a versatile, long-life grease. It is suitable for the lubrication of rolling and sliding friction parts of various mechanical equipment with working temperatures ranging from -20 °C to 120 °C. It can replace calcium-based, sodium-based, and calcium-sodium-based greases and is widely used in high-temperature, high-speed, mechanical parts in contact with water. Such as cars, tractor wheel bearings, small and medium-sized motors, pumps, and blowers. Also suitable for mining machinery, automobiles, tractor wheel bearings, large and medium engines, and other equipment. It can be used in an environment of about 120 °C for a long time.

4. Notes

(l) The large container is easy to produce oil separation. If there is a small amount of oil, it can still work after stirring evenly.

(2) It cannot be mixed with other greases.