Industrial uses of soap and synthetic detergents

Abstract

S OAP and synthetic detergents are used by practically every industry as an essential raw material or operating supply. The importance of these materials to industry and service organizations was brought into sharp focus during World War II when a general shortage of fats and oils threatened to curtail the supply for industry to such an extent that production would be hampered and the war effort impeded. During 1942 federal regulations were created that seriously reduced the quantities of fat and oil that could be used for household packaged soap, but the government at that time recognized the importance of soap for industrial applications and, with the exception of inventory controls to prevent hoarding, provided sufficient fat for all industrial soap requirements. The exact origin of soap probably cannot be stated with accuracy, but more than 2,000 years ago soap plants were in operation, as revealed in excavations among the ruins of Pompeii. The first industrial use of soap on a relatively large scale might be considered to have been in the textile industry during the 15th century for silk degumming. The same industry initiated the use of synthetic detergents in dyeing operations during the first quarter of the 20th century. Since its early use in industry more than 400 years ago, soap now finds application in many important industrial applications. Among the service trades the commercial laundry is the prime user of soap products. Many manufacturing industries, including the previously mentioned textile industry as well as paper, rubber, metal finishing, leather, wire and metal drawing, paint, cement and ceramics, all require soap as an important raw material in operations. All of these applications will be discussed more or less in detail as to the manner in which soap is used and the specific requirements of the soap. I t might be well to consider the chemical characteristics of soap employed by industry so that the selection of the proper type in the different industries may be correlated to the composition. The bulk of industrial soap i s made from animal tallow and grease. The characteristic of this soap is a high melting point or titer of the fat ty acids obtainable from the soap. Tallow produces a soap of 42 degrees centigrade titer, and grease produces lower titer soaps varying down to 35 degrees centigrade. It is interesting to note that the fat ty acids obtainable from natural fats may be separated into varying fractions of different melting points. Many industrial soaps of very low titer really have their origin from tallow after stearic and palmitic fat ty acids have been separated from the liquid oleic acid. The second type of soap made from natural fats and oils, and in this case primarily oils, shows a titer of from 20 to 25~ This type of soap may be made from olive oil and its derivatives as well as from corn, peanut, soya bean, cottonseed and a few other less prominent oils. With the exception of liquid soap, for which many manufacturers employ 100% coconut oil, we find that the use of coconut oil is restricted to modifying the properties of animal fat soaps. For example, a standard blend of 75% tallow and 25% coconut oil is used to produce a type of soap having a titer of approximately 35 degrees, which is readily soluble and has quick foaming characteristics. All of the foregoing soap products are available as so-called neutral soaps or with added alkalies of the carbonate, silicate, and phosphate type to modify the properties and efficiency of the soap product. The soap products are produced in liquid, bar, chip, and granulated forms.