Bleaching composition.

0001The present invention relates to a bleaching and cleaning composition, and more in particular to a liquid thickened chlorine bleaching composition which is based on an aqueous solution of alkali metal hypochlorite.

0002Aqueous solutions of an alkali metal hypochlorite are widely used as disinfectant cleaners for lavatory pans, urinals, drains and waste pipes, but may also be employed in the cleaning and bleaching of fabrics.

0003In British Patent Specification N° 1 329 086 it has been recognized that the efficiency of such solutions is considerably increased by thickening to viscosities at which they adhere much longer to non-horizontal surfaces, thereby enabling them to perform their bleaching/ cleaning function before draining off.

0004In the British Patent 1 329 086 thickened chlorine bleaching compositions are described, which have an active-chlorine content of 1 to 15% by weight and a thickening detergent-active system comprising an alkali metal salt of a fully saturated C₈-C₁₈ fatty acid in combination with, inter alia, a trialkylamineoxide having a straight chain C₈-C₁₈ alkyl group and two ^C_l-^C₃ groups.

0005In general, present-day bleaching products based on the above thickening system contain the commercially available amineoxides derived from naturally occurring fatty acids such as coconut acids, lauric acid and myristic acid.

0006It has now been found that if a substantial proportion (which will be defined below) of the long-chain alkyl groups of the amineoxide are C₁₆-C₁₈ alkyl groups, the thickening action is significantly improved and accordingly levels of the thickening active system may be reduced. Furthermore it has been found that, in particular if higher proportions of amineoxide have C₁₈ alkyl groups, the weight ratio of the amineoxide to the co-active may be decreased, which in general leads to a further reduction in costs.

0007Accordingly the present invention provides a liquid thickened chlorine bleaching composition comprising an aqueous alkali-metal hypochlorite solution which is thickened by means of a detergent-active mixture comprising a mono(C₈-C₁₈)-di(C₁-C₃) alkylamine-oxide, characterized in that at least 20% by weight of the amineoxide component have C₁₆-C₁₈ alkyl-groups.

0008The thickening active system consists of at least two different detergent-active components, one of which comprises a trialkylamineoxide having two short chain C_l-C₃ alkylgroups and a long chain C₈-C₁₈ alkylgroup. In order to obtain the advantages of the present invention at least 20%, preferably 20 to 50%, and most preferably 30 to 50% by weight of the amineoxide should contain long chain alkylgroups having 16-18 carbon atoms. Higher proportions of amineoxide having C₁₈ alkyl groups have an increasing effect on the cloud point of the composition and in general allow a reduction of the amineoxide/co-active weight ratio. Accordingly it is preferred that in the C₁₆-C₁₈ alkylamine-oxide fraction the amount of C₁₈-alkyl exceeds that of C₁₆-alkyl.

0009The second detergent active component present in the thickener can be an alkalimetal soap or mixture thereof according to British Patent Specification 1 329 086, alkalimetal acylsarcosinates or -alkyltaurides according to British Patent Specification 1 466 560 or sugar esters according to Dutch Patent Application 7 605 328, or mixtures thereof. Alkali metal C₁₀-C₁₈ alkylether (containing 1-10 moles of ethylene- and/or propyleneoxide) sulphates can also be used. However, the mixtures of trialkylamineoxides and alkali metal soaps of fully saturated C_a-C₁₈ fatty acids are preferred.

0010The thickening active system is used in an amount of 0.3-5%, preferably 0.5-3% by weight of the final composition.

0011The composition may be thickened to a wide range of viscosities, preferably from about 10 to 250 cS or even from about 30 to 150 cS as measured with a U-tube viscosimeter at a temperature of 25°C.

0012The stability of the composition may be improved by the addition of a small amount, in the order of 0.1-15%, of alkaline agents, such as for example sodium carbonate, trisodium orthophosphate, sodium hydroxide and the like.

0013The alkali metal hypochlorite will generally be present in the composition in an amount sufficient to provide from 1 to 15%, preferably 2 to 11% and most preferably 5 to 10% by weight of available chlorine on the basis of the total weight of the composition.

0014Although alkali metal hypochlorites are preferred, other chlorine compounds which yield the hypochlorite ion in alkaline aqueous solution may also be used, e.g. calcium and magnesium hypochlorite, alkali metal dichloro-isocyanurate, chloramines and the like.

0015Further, the thickened chlorine bleaching compositions according to the invention may contain small amounts of conventional additives, such as hypochlorite-soluble and stable colorants and perfumes. Small amounts of insoluble solid particles are also tolerable.

0016The compositions of the invention can be prepared in conventional ways, for example as described in British Patent Specification 1 329 086.

0017The compositions of the invention are useful for all bleaching purposes, especially for bleaching hard surfaces, such as toilets, tiles, floors, kitchen sinks, etc., where by their thickened nature they adhere longer to the surface than non-thickened bleaching compositions.

0018The invention will be further illustrated by way of example, in which all percentages are by weight unless otherwise indicated.

0019The following general composition was used in all examples: <tables id="tabl0001" num="0001"><img file="EP0145084A2_D0001.tif" /></tables>

0020In Table 1 comparative examples are given, illustrating for products with constant active level the effects of varying amineoxide compositions on viscosity and cloud- point behaviour. <tables id="tabl0002" num="0002"><img file="EP0145084A2_D0002.tif" /></tables>

0021In Table 2 comparative examples are given illustrating for products having the same viscosity (~45 cS) and cloud point (~43°C) the reduction in active level for varying amineoxide compositions. <tables id="tabl0003" num="0003"><img file="EP0145084A2_D0003.tif" /></tables>

0022In Table 3 comparative examples are given illustrating for products having the same cloud point (45°C) the effect on viscosity for varying amineoxide compositions (using mixtures of Coco-AO and Tallow-AO) and reduction in soap level. <tables id="tabl0004" num="0004"><img file="EP0145084A2_D0004.tif" /></tables>

0023In Table 4 comparative examples are given illustrating for products having the same viscosity (25 cS) the reduction in active system. <tables id="tabl0005" num="0005"><img file="EP0145084A2_D0005.tif" /></tables>

0024Examples 20 and 21 show improved foaming behaviour.

0025In Table 5 comparative examples are given illustrating the effect of varying amineoxide compositions for other co- actives. <tables id="tabl0006" num="0006"><img file="EP0145084A2_D0006.tif" /></tables>