Interox Chemicals Limited

Christopher T Wright

Paul L Baxter

Iain S MacKirdy

Eileen M Diakun

It is desired to enhance the ability of hydrogen peroxide and persalts at wash temperatures of around 30.degree. to 70.degree. C., in order to use less energy and to minimize damage to various fabric finishes. It has been proposed in the past to use transition metal compounds, including cobaltous compounds for this purpose, but the literature is self-conflicting in the way to do this. In repeat trials the simple cobaltous salts did not show much activation. The invention provides a class of activators for persalts and hydrogen peroxide comprising cobalt III ammine complexes, preferably containing 4 or 5 ammine ligands obeying the formula:

Bleach activation

It has been suggested hitherto that the bleaching performance of hydrogen peroxide or persalts developing it in situ at ambient to hand hot (e.g. up to 60.degree. C.) temperatures can be enhanced by addition of a transition metal catalyst, but recent investigations revealed that when manganese is selected as catalyst its performance can range from nil enhancement to a substantial improvement. The present invention is based upon the recognition that manganese catalysis of hydrogen peroxide is promoted by the presence of at least an equimolar amount of calcium, barium or strontium compound, and preferably a molar ratio of at least 50:1.

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Warrington, United Kingdom

Christopher T Wright