Calcium stearate
Encyclopedia
Calcium stearate is carboxylate of calcium
that is found in some lubricant
s and surfactant
s. It is a white waxy powder.
, a fatty acid
, and calcium oxide
:
It is also the main component of soap scum
, a white solid that forms when soap is mixed with hard water
. Unlike soaps containing sodium and potassium, calcium stearate is insoluble in water and does not lather well. Commercially it is sold as a 50% dispersion in water or as a spray dried powder. As a food additive
it is known by the generic E number
E470.
Calcium
Calcium is the chemical element with the symbol Ca and atomic number 20. It has an atomic mass of 40.078 amu. Calcium is a soft gray alkaline earth metal, and is the fifth-most-abundant element by mass in the Earth's crust...
that is found in some lubricant
Lubricant
A lubricant is a substance introduced to reduce friction between moving surfaces. It may also have the function of transporting foreign particles and of distributing heat...
s and surfactant
Surfactant
Surfactants are compounds that lower the surface tension of a liquid, the interfacial tension between two liquids, or that between a liquid and a solid...
s. It is a white waxy powder.
Production and occurrence
Calcium stearate is produced by heating stearic acidStearic acid
Stearic acid is the saturated fatty acid with an 18 carbon chain and has the IUPAC name octadecanoic acid. It is a waxy solid, and its chemical formula is CH316CO2H. Its name comes from the Greek word στέαρ "stéatos", which means tallow. The salts and esters of stearic acid are called stearates...
, a fatty acid
Fatty acid
In chemistry, especially biochemistry, a fatty acid is a carboxylic acid with a long unbranched aliphatic tail , which is either saturated or unsaturated. Most naturally occurring fatty acids have a chain of an even number of carbon atoms, from 4 to 28. Fatty acids are usually derived from...
, and calcium oxide
Calcium oxide
Calcium oxide , commonly known as quicklime or burnt lime, is a widely used chemical compound. It is a white, caustic, alkaline crystalline solid at room temperature....
:
- 2 C17H34COOH + CaO → (C17H34COO)2Ca + H2O
It is also the main component of soap scum
Soap scum
Soap scum is an informal term for the white solid that results from the addition of soap to hard water. Hard water contains calcium or magnesium ions, which react with the fatty acid component of soap to give what are technically called lime soaps:In this reaction, the sodium ion in soap is...
, a white solid that forms when soap is mixed with hard water
Hard water
Hard water is water that has high mineral content . Hard water has high concentrations of Ca2+ and Mg2+ ions. Hard water is generally not harmful to one's health but can pose serious problems in industrial settings, where water hardness is monitored to avoid costly breakdowns in boilers, cooling...
. Unlike soaps containing sodium and potassium, calcium stearate is insoluble in water and does not lather well. Commercially it is sold as a 50% dispersion in water or as a spray dried powder. As a food additive
Food additive
Food additives are substances added to food to preserve flavor or enhance its taste and appearance.Some additives have been used for centuries; for example, preserving food by pickling , salting, as with bacon, preserving sweets or using sulfur dioxide as in some wines...
it is known by the generic E number
E number
E numbers are number codes for food additives that have been assessed for use within the European Union . They are commonly found on food labels throughout the European Union. Safety assessment and approval are the responsibility of the European Food Safety Authority...
E470.
Applications
- Calcium stearate is as a flow agent in powders including some foods (such as SmartiesSmarties (Ce De Candy)In the United States, Smarties are a type of artificially fruit-flavored tablet candy produced by Smarties Candy Company, since 1949. They are marketed in Canada under the brand name Rockets, to avoid confusion with Nestlé Smarties. They are similar to the English Fizzers from Swizzels Matlow...
), a surface conditioner in hard candies such as SpreeSpree (candy)Spree is a candy manufactured by The Willy Wonka Candy Company, a brand owned by Nestlé. Introduced in 1971, Spree is classified as a compressed dextrose candy, covered in a colored fruit-flavored shell. It is currently available in rolls. In Southwest U.S. markets and in Mexico it is available in...
s, a waterproofing agent for fabrics, a lubricant in pencils and crayons. - The concrete industry uses calcium stearate for efflorescenceEfflorescenceIn chemistry, efflorescence is the loss of water of crystallization from a hydrated or solvated salt to the atmosphere on exposure to air.-Examples:...
control of cementitious products used in the production of concrete masonry units i.e. paver and block, as well as waterproofing. - In the paper production, calcium stearate is used as a lubricant to provide good gloss, preventing dusting and fold cracking in paper and paperboard making.
- In plastics, it can act as an acid scavenger or neutralizer at concentrations up to 1000ppm, a lubricant and a release agent. It may be used in plastic colorant concentrates to improve pigment wetting. In rigid PVC, it can accelerate fusion, improve flow, and reduce die swell.
- Applications in the personal care and pharmaceutical industry include tablet mold release, anti-tack agent, and gelling agent.
- Calcium stearate is a component in some types of defoamersDefoamerA defoamer or an anti-foaming agent is a chemical additive that reduces and hinders the formation of foam in industrial process liquids. The terms anti-foam agent and defoamer are often used interchangeably....
.