How to make PCS based oxygen bleach system stable in powder detergent formulations?
Detergent compositions containing sodium percarbonate are known in the art. Sodium percarbonate is an attractive perhydrate for use in detergent compositions because it dissolves readily in water, is weight efficient and, after giving up its available oxygen, provides a useful source of carbonate ions for detergency purposes. However, the inclusion of percarbonate salts in detergent compositions has been restricted by the relative instability of the bleach both as is and in use. Sodium percarbonate loses its available oxygen at a significant rate in the presence of ions of heavy metals such as iron, copper and manganese and also in the presence of moisture, these effects being accelerated at temperatures in excess of about 30.degree. C. To solve this problem, several solutions have been found. 1, Sodium percarbonate is coated with a hydrophobic substance or the like. 2, Magnesium silicate is incorporated in a detergent composition containing sodium percarbonate. 3, A chelating agent wh
