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In Chemistry, soap is a salt of a fatty acid.〔IUPAC. "(''IUPAC Gold Book – soap'' )" ''Compendium of Chemical Terminology'', 2nd ed. (the "Gold Book"). Compiled by A. D. McNaught and A. Wilkinson. Blackwell Scientific Publications, Oxford (1997). XML on-line corrected version: created by M. Nic, J. Jirat, B. Kosata; updates compiled by A. Jenkins. ISBN 0-9678550-9-8. . Accessed 2010-08-09〕 Consumers mainly use soaps as surfactants for washing, bathing, and cleaning, but they are also used in textile spinning and are important components of lubricants. Soaps for cleansing are obtained by treating vegetable or animal oils and fats with a strongly alkaline solution. Fats and oils are composed of triglycerides; three molecules of fatty acids attach to a single molecule of glycerol.〔Cavitch, Susan Miller. ''The Natural Soap Book''. Storey Publishing, 1994 ISBN 0-88266-888-9.〕 The alkaline solution, which is often called lye (although the term "lye soap" refers almost exclusively to soaps made with sodium hydroxide), brings about a chemical reaction known as saponification. In this reaction, the triglyceride fats first hydrolyze into free fatty acids, and then these combine with the alkali to form crude soap: an amalgam of various soap salts, excess fat or alkali, water, and liberated glycerol (glycerin). The glycerin, a useful by-product, can remain in the soap product as a softening agent, or be isolated for other uses.〔 Soaps are key components of most lubricating greases, which are usually emulsions of calcium soap or lithium soap and mineral oil. These calcium- and lithium-based greases are widely used. Many other metallic soaps are also useful, including those of aluminium, sodium, and mixtures of them. Such soaps are also used as thickeners to increase the viscosity of oils. In ancient times, lubricating greases were made by the addition of lime to olive oil.〔Thorsten Bartels et al. "Lubricants and Lubrication" in Ullmann's ''Encyclopedia of Industrial Chemistry'', 2005, Weinheim. 〕 Soap is very important for effective hand-washing and hygiene, but if it is not available in difficult situations, then people can use clean ash or sand / soil as a substitute - as recommended by (for example) the World Health Organization.〔 WHO, accessed October 2014 http://www.who.int/water_sanitation_health/emergencies/qa/emergencies_qa17/en/ 〕 ==Mechanism of cleansing soaps== 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「soap」の詳細全文を読む スポンサード リンク
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