IE57534B1 - Bleaching compositions - Google Patents

Abstract

Aqueous hypochlorite bleach compositions are provided comprising from 0.1% to 5.0% of a C10-C18 alkyl C1-C4 alkyl diamine oxide or a C8-C18 alkyl substituted betaine together with from 0.001% to 0.25% of an organosilicon quaternary ammonium compound containing a C16-C20 alkyl group wherein the ionic strength ofthe compositions is less than 5.0 g moles/dm<3>.

Description

This invent ion relates to hypochlorite bleach ccnposi tions and in particular to aqueous hypochlorite bleaches containing a bactericidal material.

Aqueous bleach ccnposi tions containing alkali metal 5 hypohalites, particularly sodium hypochlorite, have been known for many years. Because of their powerful oxidising action they have also been acknowledged to be powerful germicides and have been used extensively there this property is beneficial, e.g. in the cleaning of baths, wash basins, flush toilets, drains and ceramic tile floors. However, it has long been recognised that the germicidal effectiveness of surface treatments using such materials is limited by the relatively short period of time during Which the aqueous ccnposition containing the hypohalite is in contact with the surface concerned. Recent developments in the formulation of hypochlorite bleach products have shown a trend towards the use of higher viscosities, viz. -42-1 n s ' or greater, and this will increase the retention of such products on non horizontal surfaces.

Nevertheless, the increase in retention time introduced by such a thickened formulation will not be particularly significant, being measured in seconds or at most minutes, and a need exists for a bactericidal and germicidal material that is capable of retention cm a target surface for much longer periods.

Quaternary anmonium compounds, in general, are known to have bactericidal characteristics, and certain water soluble quaternary ammonium surfactants such as cetyl pyridinium bromide are very effective antibacterial agents. Polymeric dialkyl siloxane and silane structures are well known as having a high affinity for siliceous surfaces and thus a combination of a quaternary ammonium function and a siloxane or silane grouping might be expected to provide a long lasting antibacterial effect on siliceous surfaces of the type montirtned above· Such is indeed the case and the antimicrobial effectiveness of a representative alkoxy silane (3(trimethaxy silyl) propyl dimethyl octadecyl anmonium chloride) on a variety of surfaces, siliceous, metallic, synthetic, plastic and natural textile in nature, has been reported by A J Isquith et al in J. Applied Microbiology, 24 (6), 1972, pp 859-863.

However, the incorporation of quatemised alkoxy silanes into aqueous cleaning or bleaching conpositions poses considerable difficulty. All alkoxy silanes of this type will hydrolyse in contact with water, to produce the corresponding silanol derivatives which themselves are prone to polymerisation via condensation of the silanol groups.

The polymerised materials are less surface substantive than the parent si lands.

In the case of the more water soluble alkoxy silanes, containing a ^2^14 in the quaternary ammonium portion of the molecule; the materials display physical stability in aqueous alkalis and commercial aqueous hypochlorite and also display surface substantive properties. However, in the presence of hypochlorite-stable surfactants, surface substantivity is markedly impaired due to solubilisation into surfactant micelles. Furthermore, these shorter chain alkyl quatemised alkoxy silanes do not display broad range antibacterial efficacy.

Quaternary alkoxy silanes containing an alkyl chain longer than are less water soluble and do not even display long term stability in aqueous alkaline solutions but precipitate therefrom, probably in polymerised, and hence antibacterially ineffective, form.

However, it has surprisingly been found that those qua tern ised alkoxy silanes containing a alkyl group can be incorporated into certain aqueous hypochlorite bleach conpositions to produce a physically stable product capable of delivering hydrophobic properties and a long lasting antibacterial effect to siliceous surfaces treated therewith.

Aqueous hypochlorite bleach compositions forming suitable vehicles for the delivery of the quatemised alkoxy silanes should be free or substantially free of anionic surfactants and preferably should have a low ionic strength.

Accordingly the present invention provides a chlorine bleach-containing composition comprising i) a surfactant, ii) a chlorine bleach, iii) non-bleach inorganic compounds, iv) an organosilicon mono-long chain alkyl quaternary ammonium compound of formula (R3)y(R3O)3_ySi(CH2)3 25wherein Rx is long chain alkyl, R2 is C^-C* alkyl, R3 is C1~C4 alkyl, y is an integer from 0 to 2 and X- is a water soluble anion; or the silanol derivative thereof * wherein R3 is H; and v) compatible optional ingredients, wherein a) the composition is aqueous, the percentage weight of water present together with that of components i) to v) totalling 100% by weight, b) the chlorine bleach is an alkali metal hypochlorite comprised in the amount of from 1% to 12% by weight, c) the surfactant is selected from amine oxides of formula R^RgRgN-K) wherein R4 is a c10"c18 alkyl group and R5 and Rg are C.j-C4 alkyl groups, substituted betaines of formula R7RgRgN+ - R^qCOo" where R? is a Cg-C18 alkyl group, Rg and Rg are cx"c4 alkyl groups and R10 is a Cj-C* alkylene group and mixtures thereof, and is comprised in the amount of from 0.1% to 5% by weight, d) the ionic strength of the composition is less than 5.0 g moles/dm and the pH of the composition is in the range from 10 to 13, e) the alkyl group R^ of the organosilicon compound contains from 16 to 20 carbon atoms, this organosilicon compound being comprised in the amount of from 0.001% to 0.25% by weight, f) the composition is substantially free of anionic surfactant species and, g) the non-bleach inorganic compounds are comprised in the amount of from 1% to 15% by weight. ι Preferably the ccnposition contains from 0.005% to 0.05% and most preferably from 0.01% to 0.03% of the organosilicon quaternary ammonium conpound. Preferably R^ is a C^g alkyl group.

In highly preferred oonpositions in accordance with the invention, the viscosity of the composition is at least 2 x 10 ^Pa.s at 20¾ aid conprises alkali metal hypochlorite in an amount of from 8% to 10% by weight, a alkyl dimethyl amine oxide as the only surfactant in an amount of from 1.0 to 1.5% by weight together with at least 400ppm of a secondary or tertiary alcohol as hereinafter defined or the ester thereof with a C2_C3 alkanoic acid, and the composition has an ionic strength of less than 4.0 g moles/dn?.

The above mentioned reference to viscosity is to the dynamic viscosity Vj which is measured by a Brookfield RVT viscometer and for the purposes of this specification measurements are made with Spindle No. 3 at 100 rpm and a liquid tenperature of 20eC. Fluid viscosity can also be expressed as the kinematic viscosity i) in mm^/s (centistokes) as measured by an Ostwald viscometer and is characterised by the expression where yis the dynamic viscosity in mPa.s (centipoises) and is the density in g/cm^. Oonpositions in accordance with the present invention have a density in the 3 range from 1.10 to 1.25 g/cm , typically approximately 1.15 , 3 * g/cm , so that the numerical value of the kinematic viscosity in mn /s is slightly less than that of the dynamic viscosity in mPa.s.

Organosilicon quaternary ammonium conpounds having the desired combination of broad spectrum antibacterial activity and physico chemical stability in compositions in accordance with the invention have the general structure: «2 I N+ —*i x_ ι «2 wherein is c16"C2o is is Cj-C4 alkyl, y is an integer from 0 to 2, and X~ is a water soluble anion. A preferred chain length for is C18 for antibacterial efficacy reasons, and for reasons of cost and ease of preparation Rg and R^ are usually methyl. In aqueous alkaline solution the (RjO) groups will hydrolyse to give the silanol derivative or, depending on the pH, the corresponding zwitterion, so that references herein to the organic silicon quaternary ammonium conpound include the silanol derivative thereof. X- is normally halide, particularly chloride, but can also include methosulphate, acetate or phoEphate.

The level of incorporation of the organosilicon conpound is from 0.001% to 0.25% based on the total weight of the composition but is more usually in the range of from 0.005% to 0.05% and most preferably from 0.01% to 0.03% hy weight.

In compositions in accordance with the invention, the hypochlorite bleach, and the alkali metal chloride and chlorate salts which accompany it in commercially available material, provide the majority and preferably substantially all of the ionic strength requirement. This will normally result in an ionic strength of at least 3.0 g moles/dm .

Ionic strength values in excess of 5.0 g moles/dm are not desirable beacuse of their adverse influence on the stability of both the hypochlorite and organosilicon quaternary ammonium compound components. Preferably the ionic strength 3 is less than 4.0 g moles/dm and values in the region of 3.4-3.8 g moles/dm are considered to be optimum there a stable product of vieoosity £2x 10-1Pa.s is desired.

The alkali metal hypochlorite may be a lithium, potassium or sodium hypochlorite and the level of hypochlorite in the conposition is normally arranged to lie in the range 1-12%, preferably 5-10% by weight. Customarily hypochlorite bleach conpositions contain approximately 6% or 9% hypochlorite by weight. However, the activity of chlorine bleaching conpositions is conventionally expressed in terms of the weight percentage of available chlorine in the conposition, and the actual weight percentage of bleaching species is arranged to provide the desired level of 'available chlorine'. The preferred hypochlorite species is sodium hypochlorite which contains 95.3% available chlorine.

Alkali metal hypochlorites are connercially available as aqueous solutions containing 10-15% hy weight 'available chlorine* and the bulk suppliers normally produce material having available chlorine contents towards the upper end of this range viz. 12-14% hy weight. These commercially available hypochlorite solutions contain other salts as byproducts or contaminants, more specifically free alkalinity in the form of alkali metal hydroxide and alkali metal carbonate, and alkali metal chloride. Low levels of other species such as sodium chlorate are also believed to be formed during hypochlorite manufacture but their chemical stability is sufficiently low that they have largely decomposed by the time the hypochlorite is employed in product formulations. The levels of the byproduct materials depend an the processing conditions employed in the manufacture of the hypochlorite but in general they fall within the ranges 0.2 - 1.0% alkali metal hydroxide 0.01 - 0.1% allali metal carbonate .0 - 18.0% alkali metal chloride expressed as a weight percentage of the hypochlorite solution as supplied.

Amine oxides useful in the present invention have the formula R^R^RgN->0 wherein R* is a alkyl group and and Rg are C^-C^ alkyl groups.

The amine oxide is present in an amount of from 0.5% to 5%, more preferably from 0.5% to 2.5% and, in preferred embodiments of the invention in vhich the R^ average chain length «14 carbon atoms, from 1% to 1.5% ty weight of the exposition. The R^ group may be linear or branched and may be derived from natural or synthetic hydrocarbon sources. For the purposes of the present invention linear groups are defined as including moieties incorporating up to 25% methyl branching, predominantly in the 2-position relative to the nitrogen atom of the amine oxide.

Methyl branching on the alkyl chain also predominates in j those amine oxides useful in the present invention in which the R^ group is branched, rather than linear in nature.

Commercially available sources of these amine oxides are normally a mixture of R5 I R—— CH-0¾—N —r 0 where R7 is methyl, and R7 R6 R5 I R— — CH^·· * CHy— M 9 0 , R® which mixture arises as a result of the processing route used to farm the precursor alcohol or aldehyde. This route involves carhonylating or hydroformylating an olefin, preferably a linear«C-olefin and leads to a mixture of the desired branched chain aldehyde or alcohol of the same carbon number. For olefin starting materials having a range of carbon chain length, the resultant alcohol or aldehyde mixture contains compounds of different carbon number and isomers containing straight chain and 2-alkyl branched chain alkyl groups. A typical commercially available mixture comprises 65 to 75% by weight and 35 to 25% ty weight C15 amine oxides with approximately 50% by weight straight chain and 50% by weight 2-alkyl branched chain where the 2-alkyl group is predominantly methyl. These are available from ICI under the trade name Synprolam 35 EMO* as a 30% aqueous solution. The branched chain amine oxides and mixtures thereof with linear chain amine oxides are used at levels towards the upper end of the range viz. 2% by weight of the composition and typically from 2.0% to 2.5% hy weight.

Although the above-described mixture of straight chain and branched chain alkyl dimethyl amine oxides has been found suitable for the purposes of the invention, their use does not constitute the most preferred execution of the invention. This is because a bleaching composition containing 8-10% hypochlorite and an amine oxide in which the long chain alkyl group has a carbon number of about 13.3 requires an ionic strength of at least 4.7 g moles/dm to achieve the preferred product viscosity of at least 2 x 10 Pa.s. This level of ionic strength is believe! to make the storage stability of the hypochlorite bleach less than that which is considered desirable for the expected shelf life of the product. The preferred amine oxide structure for 'thickened* products having a viscosity of 2 x 10_1Pa.s is one in which R4 is a linear group which has an average chain length in the * Trade Mark range C· Conpositions containing these preferred amine oxides require a lower amine oxide level viz. <2.0%, more typically 1.0-1.5% and also a lower ionic strength viz. 3:0 g moles/dm minimum in order to achieve target viscosity. Both of these reductions in ingredient level lead to inproved storage stability and also lower the cost of the product.

Another hypochlorite-stable surfactant suitable for the purposes of the present invention is a substituted betaine of formula W/'W00' wherein R? is a Cg-C^g alkyl group, preferably a C1Q-C14 allqrl group, Rg and Rg are Cj-C^ alkyl groups, more preferably methyl groups, and Ι^θ is a ^"^4 alkylene group more preferably a C^-Cj alkylene group. Specific examples include octyl, decyl, dodecyl, tetradecyl and hexadecyl betaines in which R^g is an ethylene or propylene group and Rg and Rg are methyl groups.

Mixtures of hypochlorite-stable surfactants are also known in the art particularly where it is desired to increase the viscosity of the system and examples of other hypochlorite-stable surfactants include saturated fatty acid soaps, alkyl sulphates, alkane sulphonates, sarcosinates and taurides. These surfactants which are anionic in type should be employed at levels which do not interfere with the efficacy of the quatemised alkoxy silane. Because of the tendency of cationic and anionic surfactant species to react to form high molecular weight, relatively water-insoluble complexes, anionic surfactants should be present at less than the amount necessary to complex the quatemised alkoxy silane completely. It has been found that quatemised alkoxy silane deposited on a siliceous surface from compositions in accordance with the invention provides 80% to 90% reduction in V bacteria (E. Ooli) count on exposed surfaces when the treated surfaces are subsequently exposed to an innoculum of fresh bacteria in a distilled water environment. However the presence in the coaposition of anionic surfactants in excess of the amount necessary to complex the quatemised alkoxy silane leads to a significant diminution of the bacteria count reduction under the same conditions.

Accordingly, the composition should be substantially free of anionic surfactants, substantially free being defined as less than the amount of surfactant necessary to completely complex the quatemised alkoxy silane, and preferably should be completely free of such surfactants.

A highly preferred optional ccnponent for hypochlorite bleach compositions suitable for incorporating the quatemised alkoxy silanes, particularly those utilising from 1.0 to 2.0% of an amine oxide wherein R^ has an average chain length of about 14 carbon atoms, is at least 400 ppm based on the weight of the composition, of at least one secondary or tertiary alcohol selected from cedrol, tetra hydro linalool, tetra hydro muguol (a 50;50 mixture of tetra hydro linalool and a positional isomer, tetra hydrcanyrcenol), verdol, dihydro terpineol, isobomeol, 4-tertiary butyl cyclo hexanol and menthol and mixtures of any of these or of their hydrolysable carboxylic acid esters. These alcohols and their Cg-C^ alkanoic acid esters are known and used as ingredients in fragrances, including those employed in detergent compositions. As such their level of incorporation conventionally lies between 10 ppm and 600 ppm of the composition depending on the perfume formulation and the nature of the detergent composition.

It has now surprisingly been found that in aqueous hypochlorite bleach solutions containing from 1.0% to 2.0% of a C^-C^g amine oxide as the only surfactant, the incorporation of at least one of the above mentioned secondary or tertiary alcohols or an ester thereof with Cj-Cg alkanoic acid provides an enhancement of the viscosity of the bleach solution and facilitates the generation of viscosities of 200 centipoises and greater at °C. Preferably the secondary or tertiary alcohol or ester is present in an amount of more than 600 ppm and, where the amine oxide level is ¢1.5% ty weight is more preferahly present in an amount of at least 800 ppm. Advantageously a mixture of the alcohols or their Cj-C^ alkanoic acid esters is used in a total amount of from 600 to 1600 ppm although it is preferred that one of the conponents of the mixture should be present in an amount of at least 500 ppm by weight of the ccnposition.

The most preferred materials are cedrol, tetrahydro linalool, tetrahydro iuyrcenol and dihydro terpineol and their acetate esters. These materials have tertiary alcohol functionality and are relatively immune to breakdown in hypochlorite-containing solutions, resulting in viscosity-enhancement effects which are stable with time.

The mode of operation of these materials in this system is not fully understood but it is hypothesised that in the absence of anionic surfactants, hydrogen bonding occurs between adjacent alcohol functions of the relatively water insoluble alcohols held in the amine oxide micelles. This is believed to lead to the formation of an extended micellar structure in the solution which provides an increased viscosity. The maximum viscosity of the system is not reached immediately upon mixing, but develops over a period of time and accordingly viscosity is measured 24 hours after the product has been made.

Thickened aqueous hypochlorite bleach oonpositions including the above mentioned alcohol derivatives are particularly preferred for the incorporation of the quatemised alkoxy silane antibacterial conponent as such compositions utilise the minimum amounts of amine oxide surfactant and ionic salts necessary to generate the desired product viscosity and hence enhance the stability of the quatemised alkoxy silanes.

As stated hereinbefore, the salts accompanying the hypochlorite K bleach provide most if not all of the ionisable species necessary for the ionic strength requirement. However, other non surface ( active organic or inorganic compounds can be added where necessary to provide an ionic strength in the desired range.

The ionisable compound(s) can be inorganic in nature eg. hydroxide, sulphate, halide, (particularly chloride), carbonate, nitrate, or orthophosphate, pyrophosphate, or polyphosphate, or organic such as formate, acetate or succinate.

In the preferred embodiments of the invention inorganic conpounds such as silicates and organic compounds incorporating oxidisable groups are avoided because of their tendency to have adverse effects on physical arid/or chemical stability of the compositions on storage. Certain organic sequestrants such as the amino poly (alkylene phosphonates) salts can, however, be incorporated in an oxidised form in thich they are not susceptible to attack by the hypochlorite bleach. Such sequestrants are normally present in amounts of from 0.1% to 0.5% by weight of the composition.

The ionic strength of the composition is calculated by means of the expression Total Ionic Strength I there C* is the molar concentration of the ionic species in g moles/dm^ is the valency of the species.

The function C*Z? is calculated for each of the ionic species in solution, these functions are summed and divided by two to give the composition ionic strength.

The ionisable alkali metal ccnpound normally comprises a caustic alkali such as sodium or potassium hydroxide either alone or in admixture with alkali metal salts. This gives a composition pH (as is) of 10 to 13, although in-use the pH of the bleaching solution normally has a value in the range from 11 to 12.

For product safety reasons the amount of caustic alkali is normally limited to a value in the range of from 0.5% to 2%, more usually from 0.75% to 1.5% by weight of the composition.

A desirable optional conponent of oonpositions in accordance 10 with the invention is a perfume which is present at a level of from 0.01% to 0.5% preferably from 0.05% to 0.25% ty weight of the ccnposition. In the preferred thickened bleach compositions incorporating one or more of the above described secondary or tertiary alochol components the alcohol conponent(s) can conveniently he incorporated in the perfume mixture.

A further desirable optional conponent in oonpositions in ; accordance with the invention is an agent for siliceous glaze protection such as zinc oxide, or aluminium oxide and water soluble bismuth salts. This can be added in an amount of from 0.01% to 0.1% ty weight of the ccnposition more preferably from 0.02% to 0.06% ty weight.

The oonpositions are made ty conventional mixing techniques. Because of the relatively low aqueous solubility of the organo silicon ccnpound which is normally supplied as a solution in methanol, a premix of the amine oxide, perfune, added caustic alkali and water is normally prepared and the organo silicon eonpound is then added with vigorous agitation.

This mixture is then added to the hypochlorite solution to make the final product. Other orders of addition can be used but unless the amine oxide is present in the solution to which the organo silicon eonpound solution is added, problems of incomplete solution or precipitation can arise.

The invention is illustrated in the following exanples in which percentages are expressed hy weight of the composition unless otherwise stated. 6 In the Examples, reference to ingredients have been abbreviated as follows: Cj^EMAO CX5 alkyl dimethyl amine oxide in which the alkyl group is 95% < CX5 and approximately 50% of the alkyl groups contain methyl branching on the 2-carbon atom. ΟχψΧΑΟ CX4 alkyl dimethyl amine oxide in vhich the alkyl gxoqp is a predominantly linear CX4 ( 94%) moiety. Available from Albright & Wilson Ltd as Etapigen 0ΗΪ NaCl Sodium chloride NaOH Sodium hydroxide NaOCl Sodium hypochlorite EXAMPLE 1 420g of a 30% solution of C^ alkyl dimethyl amine oxide was added to 3555.6 g of demineralised water and 12.5 g of a perfume material containing 6.4g of isobornyl acetate was dispersed therein. To this solution was slowly added, with vigorous agitation, 11.9 g of a 42% solution in methanol of 3(trimethoxy silyl) prcpyl dimethyl octadecyl ammonium chloride (available from Dow Corning Ltd as DC 5700) to form a premix solution. 125 g of solid sodium hydroxide was dissolved in 5875 g of sodium hypochlorite solution (15.3% AvCl2 solution supplied hy ICI Ltd) and 4000 g of the premix was then blended with high shear agitation into this solution.

* Trade Mark This cooposition had the following analysis, in percent 2 ty weight and had a density of 1.15 g/cm . NjsOCl 9.43 (= 9.0% available chlorine) 3 1.46 g moles/dm NaCl 9.40 1.84...... NaCH 1.25 0.36 Amine Oxide 1.26 DC5700 0.05 Perfume 0.125 Water & Mi sc 78.485 100.000 This product was a single phase solution having a dynamic viscosity of'2.7 x IO*1 Pa.s as measured at 20eC with a Brookfield viscometer using the No. 3 spindle at 100 rpm on product that was 24 hours old.

The ionic strength of this composition was calculated to be 3.66.

EXAMPLE 2 The following compositions are prepared according to the technique of Exanple 1: (a) (b) (c) (d) c14dmvo 1.2 1.5 1.75 c15dmao 1.2 25 DC5700 0.02 0.02 0.02 0.02 NaCH 1.0 1.0 1.0 1.0 NaOCl 9.0 9.0 9.0 9.0 NaCl 9.0 9.0 9.0 9.0 Isobomeol 0.05 0.06 0.04 30 Dihydroterpinyl 0.06 acetate Water & Mi sc. -to 100 Viscosity x lO-1Ea.s 3.5 1.9 2.45 3.24 The density of each of these compositions is 1.15 g/ml and the ionic strength for each composition is calculated to he 3.5 g moles/dm^· The product viscosity was measured at 20’C 1 using the technique of Example 1. f EXAMPLE 3 The following oonpositions were prepared according to the technique of Example 1. The alcohol and ester levels are given in ppm. (a) (b) (c) (d) C14 DMftO 1.26 1.26 1.26 1.26 DC5700 0.02 0.02 0.02 0.02 NaOH 1.0 1.0 1.0 1.0 NaOCl 9.0 9.0 9.0 9.0 NaCl 9.0 9.0 9.0 9.0 Cedrol 733 733 Tetrahydrolinalool 517 Verdol 511 Dihydro terpinyl 647 acetate Isohornyl Acetate 641 641 4 Tertiary butyl 450 cyclohexyl acetate Isobomyl propionate 687 Menthyl acetate 290 Water to 100 1» Brookfield viscosity measurements were made after 24 and 72 hours and were as follows; values are in Pa.s x 10 : (a) (b) (c) (d) 24 hours 2.95 1.90 0.70* 2.40 5 72 hours 2.95 2.15 3.55 2.55 *The solution was cloudy and appeared to display non homogeneity. This disappeared after further storage.

Claims (11)

1. CLAIMSl

1. A chlorine bleach-containing composition comprising i) a surfactant? 5 ii) a chlorine bleach, iii) non-bleach inorganic compounds, iv) an organosilicon mono-long chain alkyl quaternary ammonium compound of formula (R 3 ) y (R 3 o) 3 _ySl(CH 2 ) 3 M + - s x x' , 10 wherein R^ is long chain alkyl, R 2 is C-^-C* alkyl, R 3 is alkyl, y is an integer from 0 to 2 and X** is a water soluble anion; or the silanol derivative thereof wherein R 3 is H; and v) compatible optional ingredients, 15 wherein a) the composition is aqueous, the percentage weight of water present together with that of components i) to v) totalling 100% by weight, b) the chlorine bleach is an alkali metal 20 hypochlorite comprised in the amount of from 1% to 12% by weight, c) the surfactant is selected from amine oxides of formula R 4 R g RgN4O wherein R 4 is a c 10” c 18 alkyl group ) and Rg and R fi are C 1 ~C 4 alkyl groups, substituted betaines of formula R 7 R 8 R g N + - R 4Q COO“ where R ? is a C g -C 18 alkyl group, R 0 and R g are Cj-C* alkyl groups and 5 R 1(J is a alkylene group and mixtures thereof, and is comprised in the amount of from 0.1% to 5% by weight, d) the ionic strength of the composition is less than 5.0 g moles/dm and the pH of the composition is in the range from 10 to 13, 10 e) the alkyl group R^ of the organosilicon compound contains from 16 to 20 carbon atoms, this organosilicon compound being comprised in the amount of from 0.001% to 0.25% by weight, f) the composition is substantially free of anionic 15 surfactant species and, g) the non-bleach inorganic compounds are comprised in the amount of from 1% to 15% by weight.

2. A bleaching ccnposition according to Claim 1 wherein t is and X - is a halide anion. , 20

3. A bleaching ccnposition according to either one of Claims 1 and 2 tdierein the ionic strength of the ccnposition is less than 4.0 g moles/dm .

4. A bleaching composition according to any one'of Claims 1-3 therein an alkyl dimethyl amine oxide, in vhich the alkyl group is linear and has an average carbon chain length of from 14 to 15 carbon atoms, is the only surfactant species present. '

5. A bleaching composition according to claim 4 therein the amine oxide comprises from 1.0% to 2.0% by weight of the composition.

6. A bleaching composition according to claim 5 further incorporating from 0.01% to 0.1% by weight of a glaze protection agent selected from zinc oxide aluminium oxide and water soluble bismuth salts.

7. A thickened bleaching composition according to either one of claims 5 and 6 wherein the composition incorporates at least 400ppm, by weight, of a ccmpound selected from cedrol, tetrahydro linaool, tetra hydro myrcenol, verdol, dihydro terpineol, isoborneol, 4- tertiary butyl cyclo hexanol and menthol, the hydrolysahle Cg-Cg carboxylic acid esters of any of the foregoing, and mixtures of any thereof, hereby the composition has a viscosity of 2 x 10~^Pa.s at 20°C.

8. A thickened bleaching composition according to claim 7 therein the amine oxide level is from 1.0% to 1.5% and said selected conpound is present in any amount of at least 600 ppm.

9. A thickened bleach composition according to claim 7 or 8 therein a mixture of alcohols and/or Cg-Cg alkanoic acid esters thereof is present in a total amount of from 600 ppm to 1600 ppm.

10. A thickened composition according to any one of t claims 7-9 wherein the compound is selected from cedrol, tetrahydro linacol, tetra hydro myrcenol or dihydro terpineol, the C 2 -C 3 alkanoic acid esters of any of the 5 foregoing and mixtures thereof.

11. A chlorine bleach-containing composition according to claim 1, substantially as hereinbefore described and exemplified.