Patent ID: 6107266
Filing Date: 2000-08-22
Classification: C11D

Abstract:
A process for producing coated bleach activator granules, which consists of:forming a mixture consisting of at least one dry bleach activator and at least one granulating auxiliary selected from the group consisting of cellulose ethers, starch, starch ethers, homopolymers, copolymers and graft copolymers of unsaturated carboxylic acids and/or sulfonic acids and the salts thereof, crosslinked polyvinylpyrrolidone, silicic acid, amorphous silicates, zeolites, bentonites, alkali metal phyllosilicates of the formulaMM'Si.sub.x O.sub.2x-1 *yH2Owherein M or M' is Na, K or H; x is 1.9 to 23; and y is 0 to 25; orthophosphates, pyrophosphates, polyphosphates, phosphonic acids and their salts, carbonates, and bicarbonatespressing said mixture into agglomerates, comminuting said agglomerates to form bleach activator base granules, and coating said bleach activator base granules with from 5 to 15% by weight of a coating substance having a softening or melting point of from 30.degree. C. to 100.degree. C. said coating substance is selected from the group consisting of C.sub.8 -C.sub.31 fatty acids, C.sub.8 -C.sub.31 fatty alcohols, polyalkylene glycols, nonionic surfactants and anionic surfactants, and after said coating step thermally conditioning the coated granules by heat treating in a fluidized bed for 5 to 180 minutes at a temperature of 30.degree. C. to 100.degree. C. wherein the temperature remains constant during said heat treating, but said heat treating temperature is not higher than the melting or softening point of said coating substance, thereby forming a uniform, thin coating on said base granules.