Grease, also called lubricating grease, is a thick, greasy, semi-solid substance. Used for the friction parts of machinery to lubricate and seal. Also used on metal surfaces to fill gaps and prevent rust.
Basic Composition of Grease
Grease is mainly composed of three parts: thickener, base oil and additives.
Thickener
Thickener is an important component of grease. The thickener is dispersed in the base oil and forms the structural skeleton of the grease, allowing the base oil to be 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 categories of thickeners used in preparing greases. Soap-based thickeners and non-soap-based thickeners. 90% of greases are made with soap-based thickeners.
Base Oil
Base oil is the dispersioin medium in the grease dispersion system, which has a great influence on the performance of the grease. Generally, greases mostly use petroleum lubricants of medium viscosity and high viscosity as base oils. In order to meet the needs of mechanical lubrication and sealing working under harsh conditions, some use synthetic lubricants as base oils, such as ester oil, silicone oil, Poly-alpha-olefin oil, etc.
Additives
One type of additives is needed for grease, called 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 cannot form grease. The other type of additives is the same as in lubricants, such as antioxidants, anti-wear and rust inhibitors, but the dosage is generally higher than that in lubricants. Sometimes, in order to improve the grease's ability to resist loss and enhance lubrication, some graphite, molybdenum disulfide, carbon black, etc. are often added as fillers.