Calcium soap grease

Grease is primarily a soap and lube oil mixture. The properties of grease are determined in large part by the properties of the soap component. For example, sodium soap grease is water soluble and not suitable for water contact service. A calcium soap grease, on the other hand, can be used in water service. The soap may be purchased as a raw material or may be manufactured on site as an auxiliary process. 

C Calcium soap grease. D Sodium soap grease. E Lithium soap... 

The surfactant or soap used in a grease is critical in the temperature dependence of its rheology and hardness behavior. For example, calcium soap greases become... 

Calcium base greases depend on a definite water content to stabilize the soap/oil structure. If the water is removed, the grease has a tendency to separate. For this reason calcium soap greases are not recommended for temperatures over 150°F due to water evaporation. Calcium soaps do not dissolve in water, and calcium base greases may be used in damp locations— damp or wet but not submerged in water. 

Greases may contain soaps of lithium, calcium, sodium, aluminium, etc., or they may be non-soap greases. 

Calcium complex soap greases, obtained by the reaction of lime and a mixture of fatty acids and acetic acid. These greases offer good high temperature and anti-wear/extreme pressure properties related to the presence, in the soap, of calcium acetate that acts as solid lubricant they have good mechanical stability. 

Salts of Organic Acids. Calcium salts of organic acids may be prepared by reaction of the carbonate hydroxide and the organic acid (9). Calcium lactate [814-80-2] is an iatermediate ia the purification of lactic acid from fermentation of molasses. Calcium soaps, soaps of fatty acids, ate soluble ia hydrocarbons, and are useful as waterproofing agents and constituents of greases (9). 

Calcium soaps are insoluble in water but are soluble in hydrocarbons. They tend to form jellylike masses and are used as constituents of greases and as waterproofing agents. 

To make grease the soap is dispersed in the oil as fibers of such a size that it may only be possible to detect them by microscopy. The fibers form a matrix for the oil, and the type, amount, size, shape, and distribution of the soap fibers dictate the consistency, texture, and bleeding characteristics, as well as the other properties of grease. Grease may contain from 50% to 30% soap, and although the fatty acid influences the properties of grease, the metal in the soap has the most important effect. For example, calcium soaps form smooth, buttery grease that is resistant to water but is limited in use to temperatures under about 95°C (200°F). 

Nevertheless, calcium greases of this type are still in use today for less demanding applications and their manufacture is very similar to the processes used over 100 years ago. Calcium soap is produced with a small residual water content which acts as a stabiliser for the soap matrix and thus provides the required structure of the thickener. In some operating conditions, when the temperature is constantly above 50°C, water evaporation may result in the complete breakdown of consistency in the grease and it will revert to a fluid state. 

New improved lubricating greases containing ash-free additives, the combination of lithium and calcium soaps to improve water resistance, the incorporation of functional polymers into the thickener matrix to improve spray-off properties and many more customer-specific solutions have been offered. In the pipeline are products containing functional soaps, nano particles (nested spheres) and lyotropic liquid crystals. In scientific terms, the trend is moving from know how to know why as more is understood about the actual mechanisms involved in grease lubrication. 

This section refers to the use of quicklime as a component of continuous casting lubricants and of slaked lime as a lubricant carrier in wire drawing (the use of lime in greases and calcium soaps is described in section 31.13). 

Lubricating greases frequently contain 10 to 25 % of calcium soaps dispersed in naphthenic or aromatic mineral oils. While greases containing simple soaps are only suitable for use at temperatures up to 60 °C, complex soaps can be used at up to 160 °C [32.50]. 

Soap greases (calcium base grease is an example) are made by cooking a mixture of a suitable fatty acid and a portion of the petroleum oil with calcium hydroxide. When the saponification of the acid by the lime is complete, the water content is adjusted and the remainder of the oil incorporated. A fine mesh wire screen removes impurities and lumps before packaging (Imperial Oil). 

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