Grease is mainly composed of thickener, base oil and additives. The content of thickener in general grease is about 10% -20%, the content of base oil is about 75% -90%, and the content of additives and fillers is below 5%.
The base oil is the dispersion medium in the grease dispersion system, and it has a great influence on the performance of the grease. Generally, most greases use medium-viscosity and high-viscosity petroleum lubricating oils as base oils. Some also use synthetic lubricating oils as base oils to meet the needs of mechanical lubrication and sealing under severe conditions. Poly wee-olefin oil and so on.
Thickener is an important component of grease. The thickener is dispersed in the base oil and forms the structural skeleton of the grease, so that the base oil is adsorbed and fixed in the structural skeleton. The water resistance and heat resistance of grease are mainly determined by the thickener. There are two main types of thickeners used to make grease. Soap-based thickeners (ie, fatty acid metal salts) and non-soap-based thickeners (hydrocarbon, inorganic, and organic).
Soap-based thickeners are divided into three types: single soap-based (such as calcium-based grease), mixed soap-based (such as calcium-sodium-based grease), and complex soap-based (such as complex-calcium-based grease). 90% of grease is made with soap-based thickener.
3. Additives and fillers
One type of additive is what a grease needs, called a peptizer, which makes the combination of oil and soap more stable, such as glycerin and water. Once water is lost in calcium-based grease, its structure is completely destroyed, and it cannot form fat. For example, glycerin in sodium-based grease can adjust the consistency of the fat. The other additives are the same as those in lubricating oils, such as anti-oxidants, anti-wear and rust inhibitors, but the amount is generally higher than that in lubricating oils. Such as phosphate ester, ZDDP, Elco extreme pressure antiwear agent, compounding agent, dropping point enhancer, etc. Sometimes, in order to improve the ability of the grease to resist loss and enhance lubrication, graphite, molybdenum disulfide, and carbon black are often added as fillers.