Bleaching activator granulate

#The present invention relates to bleaching activator granulate for activating peroxide bleaching agents such as percarbonates.

#Bleaching agents and bleaching detergents for clothes now available on the market contain particularly sodium percarbonate or sodium perborate as a bleaching base. However, such a base has come to be used in combination with an organic peracid precursor of N-acyl or alkanoyloxybenzene type, since a sufficient bleaching function cannot be obtained with only the base. Such a base reacts with a hydrogen peroxide compound such as sodium percarbonate to form an organic peracid having a high bleaching effect for effectively removing stains such as food stains from clothes or for bleaching yellowed clothes.

#Recently, a bleaching activator of alkanoyloxybenzene type having a high bleaching effect even in a low concentration began being incorporated into detergents. Such a compound should be granulated by a certain method, since it is easily hydrolyzed in the presence of an alkali component in the detergent. Japanese Patent Unexamined Published Application (hereinafter referred to as "J. P. KOKAI") No. Sho 61-111400 discloses a technique of coating the surface of long-chain sodium alkanoyloxybenzenesulfonate particles with a neutral or acidic, water-soluble inorganic hydrate such as Na sulfate or acidified borax to improve the storabiity and water dispersibility of the particles. Although acidic substances are preferred from the viewpoint of the storability, bleaching activators having a phenol ester group have problems that the solubility thereof is not easily improved by only granulating them with PEG or the like or by coating them with an acidic or neutral salt.

#The following Examples will further illustrate the present invention.

#A bleaching activator having an average particle diameter of 200 .mu.m as shown in Table 1, AOS (Lipolan PJ 400 having 14 carbon atoms; a product of Lion Corporation) and PEG 6000 (molecular weight: 6,000) all in the form of powders were fed into S-1KRC kneader (a product of Kurimoto, Ltd.) and kneaded under heating to about 65.degree. C. The kneaded mixture was then passed through a mesh plate having about 20 to 40 holes having a diameter of 0.8 mm to obtain needle-shaped granules having a length of 10 to 100 mm. The granules were cooled to 40.degree. C. or below by blowing cold air and then broken by slowly rotating them in a Henshel mixer to obtain rod-shaped bleaching activator granulate having a diameter of 0.8 mm and a length of 0.5 to 7 mm.

#TABLE 1 ______________________________________ Bleaching activator No. R X ______________________________________ a C.sub.11 H.sub.23 SO.sub.3 Na b C.sub.13 H.sub.27 SO.sub.3 Na c C.sub.15 H.sub.31 SO.sub.3 Na d C.sub.7 H.sub.15 COONa e C.sub.9 H.sub.19 COONa f C.sub.11 H.sub.23 COONa g C.sub.7 H.sub.15 COOH h C.sub.9 H.sub.19 COOH i C.sub.11 H.sub.23 COOH j C.sub.19 H.sub.39 SO.sub.3 Na k CH.sub.3 COOH ______________________________________