Method for the preparation of sodium percarbonate granules having enhanced stability

This invention relates to a method for the preparation of sodium percarbonate granules wherein the granule surface is modified by creating a dense thin film enhancing the stability of the final sodium percarbonate product. Further, the invention relates to these stability enhanced sodium percarbonate granules, and to the use of these granules in detergent compositions. A method for the preparation of sodium percarbonate granules having enhanced stability, comprising modifying the surface of the sodium percarbonate granules by a surface reaction between sodium percarbonate and carbon dioxide or bicarbonate species to form a dense solid film of essentially sodium bicarbonate on the surface of the sodium percarbonate granules, the method comprising the steps of:a) dissolving carbon dioxide in water to form an aqueous solution containing dissolved carbon dioxide and bicarbonate,b) exposing the surface of the sodium percarbonate granules to a spray of the aqueous solution containing dissolved carbon dioxide and bicarbonate, to form the solid film of essentially sodium bicarbonate, and subsequentlyc) removing the residual fluid from the surface.