Layered Silicates and TAED Efficient Builder Substances with an Excellent Ecological Profile

摘要

As the replacement, Zeolite A, has some weak points and also drawbacks during waste water treatment, the research i nthe field of builder products is an ongoing business. A promising chemical is layered silicate. It copes well with the before mentioned criteria and shows an excellent efficiency and outstanding compatibility with other detergent powder ingredients. As layered silicate will hydrolyse in the sewage, it will not cause problems of solid residue but only liberate silicate and sodium ions. Mainly used in detergent powders, layered silicates are about to broaden their area of application. Remarkable their ability to protect glass from corrosion, thus making them an excellent and multifunctional raw material for automatic dishwasther granulates as well. The availability and the reasonable price of sodiumperborate made it to a widely used raw material in detergent powders. Due to its low activity in the cold and the necessity to wash modern fibers at lower temperature, researchers were looking for improvements. Some tried to replace the perborate by other active oxigen compounds i.e. percarboxylic acids. Others suggested metallcomplexes as catalysts for perborate. Both ways were not really succesful. A third idea, to lower the high activation energy for the perborat decay, by using a second chemical, able to form intermediates, was workable. Among various chemicals, Tetraacetylethylendiamin gained the biggest part of the market. Introced in 1980 its consumption may reach 75 000t in 1999. In recent years TAED has been applied not only in textile detergents, but in automatic dishwashing granulates denture cleaners and other products as well. There is certainly a potential for industrial applications as paper bleach and so on. Though bleaching is the main purpose of its application, the secondary benefits as disinfection and desodorisation will keep TAED in a leading market position.