Interox Chemicals Limited

Paul L Baxter

Christopher T Wright

Iain S MacKirdy

Michael J Whiting

Under conditions of misuse, water-soluble peroxyacids when they are left in direct contact with dyed fabrics can cause spotting and dye damage. The problem can be ameliorated by surface-treating the peroxyacid with an effective amount, preferably selected in the range of 8 to 25% w/w based on the peroxyacid, of aliphatic amines which melt or soften at about 30.degree. to 70.degree. C. Preferred agents include hydrogenated tallow amine dicocoamine and methyl dihydrogenated tallow amine. The agent can be applied in molten fashion or in inert solvent such as a chlorinated aliphatic hydrocarbon onto agitated particles of the peroxyacid.

Surface treatment of peroxyacids

The bleaching performance of hydrogen peroxide or persalts developing it in situ is markedly lower at lower washing temperatures from ambient to 60.degree. C. than at hot washing temperatures of around 90.degree. C. or above. The present invention relates to compositions and processes employing a minor amount of mixed oxides of calcium, barium or strontium with manganese which activate hydrogen peroxide bleaching and washing of stains at lower wash temperatures in spite of the fact that the compounds are substantially water-insoluble. Suitable mixed oxides include those represented by formula M.sub.x MnO.sub.y in which M represents the alkaline earth metal, x ranges from 1 to 2 and y ranges from 3 to 4.

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

Paul L Baxter