COLOURED AQUEOUS ALKALIMETAL HYPOCHLORITE COMPOSITIONS

Abstract: The invention pertains to coloured aqueous alkalimetal­ hypochlorite compositions which are suitable for bleaching purposes. By inclusion in such compositions of a halogen­ ated metalphthalocyanine pigment having from 6 to 16 halogen atoms per molecule of phthalocyanine, the colour remains stable much longer than when a metal­ phthalocyanine is used having from 0 to 6 halogen atoms, at an alkalimetalhypochlorite level of 5-15% by weight. Inclusi­ on of a metal complexing agent improves the chemical stability of the coloured composition. A preferred embodi­ ment is a coloured thicknened alkalimetalhypochlorite com­ position.

Description: The present invention relates to aqueous liquid alkalimetal hypochlorite compositions which contain a colouring agent added thereto. The inclusion of colouring agents in aqueous alkalimetal hypochlorite compositions has been described before. Since, however, these compositions form a strongly oxidizing environment, the choice of a colouring additive for the purpose of colouring such a composition is very limited. Thus, potassium permanganate and potassium dichromate have been described for the purpose of colouring such compositions, but the colours they impart to these compositions (purple and yellow) are aesthetically less attractive. Ultramarine Blue has been described for the purpose of colouring hypochlorite compositions, which have no appreciable yield stress value. In Japanese Patent Application 8604/78, laid open to public inspection on 26 January 1978, it is described to include a copperphthalocyanine pigment in aqueous hypochlorite compositions to impart a blue or blue-green colour thereto. The copperphthalocyanines proposed contain from 0 to six halogen atoms per molecule of phthalocyanine, the copperphthalocyanines having 8 or 16 halogen atoms being unsuitable because of their high fading rate. This is demonstrated in the above Japanese patent application for compositions containing 3% of sodium hypochlorite. We have found that at higher sodiumhypochlorite levels, e.g. at a level of 10% by weight, the copperphthalocyanine dyes according to this Japanese patent application, containing from 0 to 6 halogen atoms, fade away rather quickly; the blue colour rapidly changes to green and/or yellow. We found, however, that the copperphthalocyanines having more than 6 halogen atoms imparted a colour to such hypochlorite compositions which remained stable for a far longer period. In view of the findings, reported in the above Japanese patent application about the instability of the colour, produced by these copperphthalocyanine dyes containing more than 6 halogen atoms, our finding was surprising and unexpected. In its broadest aspect therefore, our invention relates to a coloured aqueous liquid alkalimetal hypochlorite composition comprising as colouring agent from 0.0001-0.01% by weight of the composition of a halogenated metalphthalocyanine pigment, which is characterized by the fact that the halogenated metalphthalocyanine pigment contains more than 6 and up to 16 halogen atoms per molecule of phthalocyanine, the amount of alkalimetal hypochlorite in the composition being from 5 to 15% by weight of the composition. The halogenated metalphthalocyanine pigments according to the present invention contain more than 6 and up to 16 halogen atoms per molecule of phthalocyanine. The halogen atom may be chlorine or bromine, or a mixture of these, chlorine being preferred. Preferred are the more fully halogenated derivatives, such as the metalphthalocyanines containing 12 or 15/16 (=fully halogenated) halogen atoms per molecule of phthalocyanine. With increasing chlorine content in the molecule, the colour of the pigment progresses from blue to green, and with increasing bromine content in the molecule the colour of the pigment progresses from blue to yellow-green. The metal in the metalphthalocyanines can be any metal with which phthalocyanine forms a metal chelate complex, such as Cu, Ni, Mg, Pt, AI, Co, Pb, Ba, V and so on. Commercially available halogenated metalphthalocyanine pigments are the halogenated copperphthalocyanine pigments, typical representatives being Monastral Green GNS, a fully chlorinated copperphthalocyanine, identical with Monastral Fast Green G, C. I. No. 74260 ex ICI. Another commercially available halogenated pigment is Colanyl Green GG, identical with pigment green 7, ex Hoechst, also a chlorinated copperphthalocyanine. Other examples of suitable halogenated metalphthalocyanines according to the present invention are Helio-green K8730 ex BASF, a fully chlorinated copperphthalocyanine, Monastral Green LAG ex ICI, a partly brominated and partly chlorinated copperphthalocyanine, Monastral Green 3Y and Monastral Green 6Y ex ICI, a partly, and a fully brominated copperphthalocyanine respectively. All these trademarks are registered trademarks. The metal in these halogenated metalphthalocyanines is present in a chelated form, i.e. the halogenated phthalocyanine chelates the metal in a complex form. For the purpose of the present invention the halogenated copperphthalocyanines, especially the fully chlorinated ones, have been found to be the preferred compounds to be included in the hypochlorite compositions. According to the above Japanese patent application, the copperphthalocyanine pigments containing 0 to 6 halogen atoms do not promote decomposition of the hypochlorite. We have found, however, that such decomposition does occur when these halogenated copperphthalocyanine pigments according to this publication are used in aqueous alkalimetal hypochlorite compositions with a higher level of hypochlorite than those according to this publication. This decomposition can be measured by measuring the amount of oxygen evolved from the hypochlorite composition, and we have found that the amount of oxygen, evolved during a certain period, is much lower when using the halogenated metalphthalocyanines of the invention than with those according to the Japanese patent application. In this respect we have found that the chemical stability of the coloured alkalimetal hypochlorite composition of the invention can be further improved by inclusion therein of metal complexing agents which are oxidation-resistant and stable in aqueous hypochlorite compositions. Typical examples of suitable complexing agents are organic hydroxy carboxylic acids such as tartaric acid, malic acid, sulphosalicylic acid, furthermore inorganic acids such as telluric acid, periodic acid; these acids may also be used in their alkalimetal salt form. Mixtures of these complexing agents can also be used. The compositions of the present invention comprise the halogenated metalphthalocyanine pigment in an amount ranging from 0.0001 to 0.01 % by weight, preferably from 0.0002 to 0.0025% by weight. The amount of alkalimetalhypochlorite in the compositions ranges from 5 to 15% by weight, and the amount of metal complexing agent ranges from 0.0001 to 1.0% by weight. The aqueous alkalimetalhypochlorite composition further comprises an aqueous medium, which may contain the usual small amounts of caustic alkalies and perfumes. Not only is the aqueous composition an aqueous liquid composition, but it may also, and preferably, be a thickened aqueous liquid hypochlorite solution. Such thickened compositions are known per se from UK Patent Specifications 1 329 086; 1 466 560; 2 003 522; 2 046 321; 2 051 162; European Patent Application No. 0030401 and NL-patent application 7 605 328, all these being published specifications, and the present invention is applicable to these compositions as well. These thickened compositions comprise in the aqueous medium as thickening agent a blend of different detergent surfactants, sometimes additional electrolytes, hydrotropes, silicates etc. The thickening agent consists of at least two different detergent active compounds of which at least one must be soluble in aqueous hypochlorite solutions. Suitable examples of such washing agents are the trialkylamine oxide according to Netherlands patent No. 148 103 or German patent No. 2 837 880; betaines according to Netherlands patent No. 148 103; and quaternary ammonium compounds according to U.S. pat. No. 4 113 645 and Netherlands patent application No. 7605328. Mixtures of these washing agents can also be used. The other detergent active compounds present in the thickener can be alkali-metal soaps according to British Pat. 1 329 086, alkali-metal acylsarcosinates or -alkyltaurides according to British Pat. No. 1 466 560 or sugar esters according to Netherlands patent application No. 7605328, alkylsulphates according to British Pat. No. 2 051 162, or mixtures thereof. Alkali-metal C₁₀-C₁₈ alkylether (containing 1-10 moles of ethylene and/or propylene oxide) sulphates can also be used. However, the mixtures of trialkylamine oxides and alkali-metal soaps of fully saturated C₈-C₁₈ fatty acids as described in British Pat. No. 1 329 086 are preferred. The thickening agent is used in an amount of 0.5-5% by weight based on the final product. The weight ratio of the hypochlorite-soluble detergent active substance to the other detergent active substance in the thickening agent can vary from 90:10 to 20:80. The present invention will further be illustrated by way of example. Example 1 A thickened liquid hypochlorite composition of the following formulation was prepared: Samples of this product were taken, to which different colouring agents and complexing agents were added. Of the products thus prepared the colour stability and the stability of the hypochlorite was measured. The following Table represents the details of the additives, and the results obtained. Example 2 Example 1 was repeated, using fully chlorinated copper-phthalocyanine and sodium metaperiodate at varying levels. The following results were obtained: Example 3 Repeating Example 1, (c), but using sodiumtellurate, or sulphosalicylic acid, or malic acid, or tartaric acid instead of sodium metaperiodate gives similar results, the tartaric acid being more effective than the malic acid, which in turn is more effective than the sulphosalicylic acid. The tellurate was as effective as the periodate.

Claims: A coloured, aqueous liquid alkalimetalhypochlorite composition comprising as colouring agent from 0.0001-0.01 % by weight of the composition of a halogenated metalphthalocyanine pigment, characterized in that the halogenated metalphthalocyanine pigment contains more than 6 and up to 16 halogen atoms per molecule of phthalocyanine, the amount of alkalimetalhypochlorite in the composition being from 5 to 15% by weight of the composition. A composition according to claim 1, characterized in that the halogenated metalphthalocyanine pigment contains from 12-16 halogen atoms per molecule of phthalocyanine. A composition according to claim 1 or 2, characterized in that the halogen is chlorine. A composition according to claims 1-3, characterized in that the metalphthalocyanine is copperphthalocyanine. A composition according to claim 4, characterized in that the halogenated metalphthalocyanine is fully chlorinated copperphthalocyanine. A composition according to claims 1-5, characterized in that it further contains an oxidation-resistant, hypochlorite-stable metal complexing agent in an amount of 0.0001-1.0% by weight of the composition. A composition according to claim 6, characterized in that the metal complexing agent is sodiumperiodate. A composition according to claims 1-7, characterized in that it has been thickened in a manner known per se by inclusion therein of a blend of at least two different detergent surfactants.

Inventors: FOXLEE, JOHN CLIFFORD
Applicants: UNILEVER N.V., UNILEVER PLC
Application year: 1982
Main classification: C11D3
IPC codes: C11D3, C01B11