GB2332913A

GB2332913A - Liquid bleach composition

Info

Publication number: GB2332913A
Application number: GB9828573A
Authority: GB
Inventors: Michael Harris; Clare Ewin
Original assignee: Jeyes Group Ltd
Current assignee: Jeyes Group Ltd
Priority date: 1997-12-31
Filing date: 1998-12-23
Publication date: 1999-07-07
Anticipated expiration: 2018-12-23
Also published as: GB9828573D0; FR2773168A1; GB2332913B; GB9727517D0; FR2773168B1

Abstract

A liquid bleach composition comprising:- (i) halogen bleach component; (ii) a surfactant thickening system which comprises:- (a) an tertairy amine oxide surfactant; (b) a surfactant component comprising a secondary alkane sulphonate anionic surfactant; and (c) a solubilising anionic surfactant, particularly an alkoyl sarcosinate; (iii) electrolyte; and (iv) water.

Description

LIOUlD BLEACH COMPOSITION The present invention relates to an aqueous, hypochlorite based, liquid bleach composition which contains surfactant(s) and electrolyte(s), to thicken it. In particular the invention is concerned with compositions which retain substantial viscosity on storage and when subsequently diluted.

There have been many disclosures of thickened aqueous liquid bleaches which maintain, increase or do not markedly lose viscosity upon dilution with water. For example, WO 95/02664 discloses compositions (which include bleaches) which increase viscosity upon dilution. The thickening system comprises an ether sulphate surfactant alone or in combination with one or more anionic, nonionic, amphoteric or cationic surfactants and an electrolyte and/or hydrotrope.

A similar approach has been adopted in the proposal of WO 96/21721 where the thickening system comprises up to 15% by weight of a surfactant system comprising one or more anionic surfactants alone or in combination with one or more nonionic or amphoteric surfactants. The compositions preferably also contain a water soluble or dispersible polymeric viscosity modifier.

Exemplified within WO 95/02664 and WO 96/21721 are bleaches thickened with an alkyl ether sulphate plus amine oxide surfactant system. Within the earlier document (WO 95/02664) are exemplified thickened aqueous compositions (albeit non-bleach containing) wherein the thickening system comprises an alkyl ether sulphate in the form of sodium lauryl ether sulphate together with (respectively) one of sodium lauroyl sarcosinate, an alkyl dimethyl amine oxide, a sodium alkane sulphonate, an alkyl amido betaine, sodium lauryl sulphate and coconut diethanolamide, together with 17% by weight of electrolyte.

In practice, all of the aforementioned known thickening systems rely on electrolyte to create the structure which results in the desired high viscosity. However, the concentrated formulations tend to separate into phases and the surfactants, particularly in the separated phases, tend to promote decomposition of bleaching components. The bleach decomposition in turn increases the electrolyte concentration which further affects the viscosity characteristics. This is particularly a problem with lauryl ether sulphate based systems where the surfactant precipitates out at high electrolyte concentration, reducing viscosity and further promoting bleach decomposition.

EP-A-137 551 discloses examples of soap/amine oxide/alkyl ether sulphate; soap/amine oxide/alkyl sulphate; sarcosinate/amine oxide/alkyl ether sulphate; soap/amine oxide/secondary alkyl sulphate; and soap/amine oxide/alkyl benzene sulphonate blends in liquid bleaches. Combinations of amine oxide and sarcosinate surfactants in bleaches are known from GB-A-1 466 560. However, these blends do not show optimal viscosity characteristics upon dilution.

The present invention aims to provide a hypochlorite based liquid bleach composition which is appreciably viscous on storage and dilution, and which will retain appreciable viscosity even after appreciable bleach decomposition.

Thus, the present invention provides a liquid bleach composition comprising: (i) halogen bleach component; (ii) a surfactant thickening system which comprises: (a) a tertiary amine oxide surfactant; (b) a secondary alkane sulphonate anionic surfactant; and (c) a solubilising anionic surfactant; (iii) electrolyte; and (iv) water.

The solubilising surfactant serves to maintain the activity of the bleaching constituents in solution in the bleach composition, particularly in the concentrated composition. By keeping the thickening system in solution, the viscosity of the composition is maintained. Also, by preventing dissolution, a relatively clear, concentrated composition can be achieved.

The solubilising surfactant serves to maintain other ingredients, such as perfumes, in solution.

The solubilising surfactant will be strongly hydrophilic, with good solubilising properties and good halogen stability, and serves to prevent separation of the bleach composition into separate phases.

Particularly preferred solubilising surfactants are an alkoyl sarcosinate anionic surfactant; a soap, particularly C8 to C16 and preferably Sodium Laurate; an alkyl carboxylate, particularly Cs to C16 and preferably C12; and xylene sulphonate. The sarcosinate is especially preferred.

The tertiary amine oxide surfactant component of the thickening system is preferably selected from the class of amine oxides defined by the general formula:

in which R is a long chain straight or branched alkyl group, typically containing 8 to 20 carbon atoms; and each of the groups Rl is a lower alkyl group, typically containing 1-4 carbon atoms. Particular examples of this class of nonionic surfactants are alkyl dimethyl amine oxides such as those sold under the trade names "Empigen OB" and "Empigen OH-25D"by Albright & Wilson or "Pentanox 4XX' from Pentagon chemicals.

In this specification, the amount of material used is the amount calculated on the basis of the active material in the commercially supplied material. Thus, 2.5% by weight would be 2.5 gm of active material per 100 gm of bleach composition.

The total amount of the tertiary amine oxide surfactant in the composition is preferably from 2.5% to 5%, more preferably from 2.6% to 4.35% and especially from 3.35% to 3.85% by weight of the total composition.

The total amount of the secondary alkane sulphonate anionic surfactant is preferably less than 2%, more preferably less than 1.17%, most preferably less than 0.93% and especially from 0.57% to 0.81% by weight of the total composition.

The total amount of the solubilising surfactant is preferably less than 2%, more preferably less than 1.61% and especially from 0.89% to 1.25% by weight of the total composition.

In any event, preferably the surfactant thickening system comprises from 1% to 10%, more preferably from 2.5% to 9% by weight of the total composition.

In addition to the essential components of the surfactant thickening system, the thickening system may optionally comprise one or more other surfactants at, for example, from 0.1% to 5%, preferably from 0.5% to 2% by weight of the total composition. Such other surfactants may be selected from anionic, nonionic, amphoteric and cationic surfactants.

The bleach component is preferably an alkali metal hypochlorite bleach, particularly sodium hypochlorite. Thus, compositions in accordance with the invention may be formulated to give, upon dilution (e.g. 2 parts water to 1 part composition), a bleach product which provides bleach in an amount sufficient to give from 0.1 to 10% by weight available chlorine in the diluted product.

In any event, the bleach component as a whole preferably constitutes from 0. 1% to 15% by weight of the total composition.

The electrolyte content of the composition influences the viscosity in the neat product and upon dilution. Such electrolytes may be added as a separate component to the composition or added to one of the other components before incorporation in the product. Electrolyte may also be present as a manufacturing by-product in one of the other components, e.g. a hypohalite bleach. Reference herein to electrolyte refers to electrolyte incorporated from any source. The term refers to any metal salt of an inorganic acid and which is dissolved in the composition according to the present invention.

Suitable electrolytes may be selected from one or more of sodium chloride, sodium hydroxide and sodium carbonate (or other appropriate alkali metal salt). As the bleach degrades with storage, some of these electrolytes will tend to increase. However, as a general guide, we prefer that the total amount of electrolyte is from 0.1% to 15% by weight of the total composition, preferably from 5% to 10%, especially from 6% to 9% of the initial formulation.

Preferably, before dilution, compositions according to the present invention have a viscosity of from 50cp (centipoise) to 50,000cp, more preferably from 100cp to 10,000cp and most preferably from 500cp to 1,000cp. Upon dilution with 2 parts water to 1 part of the composition, they produce a diluted product with a viscosity preferably from 25cp to 10,000cp, more preferably from 50cp to 2,000cp and most preferably from 100cp to 500cp. All viscosities quoted herein are as measured using a Brookfield LV viscometer with spindle no. 2 at a speed of 6 rpm and at a temperature of 20"C.

Compositions of the present invention may also contain one or more other optional ingredients such as colouring agents, such as dyestuffs, fragrances, sequestrants and chlorine bleach stable viscosity modifiers. In this connection it may be noted that commercially available fragrances may in themselves have a viscosity-modifying effect.

The present invention will now be explained in more detail by way of the following non-limiting examples.

Example 1 A base composition having the formulation in Table 1 was prepared.

Neat Product Diluted Product* 1 Myristyldimethyl amine oxide 3.36 1.12 2 Lauroyl sarcosinate 1.13 0.38 3 Secondary alkane sulphonate 0.70 0.23 4 Sodium hypochlorite 7.50 2.50 5 Sodium hydroxide 1.32 0.44 6 Perfume qs qs 7 Stabiliser (sodium periodate) 0.024 0.008 8 Softened water balance balance *derived by dilution 1 part concentrate plus 2 parts water by weight.

As mentioned above, the quantity of material is the amount of active material, given as % by weight of the overall composition.

The neat product had a viscosity of about 500cps and the diluted product a viscosity of about 220cps measured using a Brookfield LV viscometer with spindle no. 2 at a speed of 6 rpm and at a temperature of 20"C.

The effect of varying the concentration of the surfactant components was then measured by varying the concentration of one component, the other two being kept constant, giving the following results: MDAO % w/w Viscosity Neat Viscosity of Dilution* 1.25 20 25 2.60 70 200 2.85 180 220 3.10 375 210 3.35 555 240 3.60 645 240 3.85 1190 255 4.10 2000 255 4.35 2920 235 Alkane Sulphonate % w/w Viscosity Neat Viscosity of Dilution 0.33 2840 55 0.45 2075 85 0.57 1385 135 0.69 755 215 0.81 380 285 093 270 395 1.05 40 515 1.17 30 530 Alkoyl Sarcosinate % w/w Viscosity Neat Viscosity of Dilution 0.77 365 280 0.89 400 265 1.01 435 255 1.13 420 215 1.25 520 185 1.37 615 160 1.49 645 125 1.61 685 115 The surfactant thickening systems remained soluble, and hence there was a simple reduction in viscosity on dilution, but to a level which, in the preferred concentration ranges, gave an acceptably high viscosity in the diluted product.

Examples 2 to 5 The following formulations were prepared and the viscosity before and after dilution was measured Example 2.

Neat Product Diluted Product Myristyl Dimethyl Amine Oxide 3.36 1.12 Lauroyl Sarcosinate 1.13 0.38 Lauryl Ether Sulphate (2 Moles EO) 0.38 0.125 Secondary Alkane Sulphonate 0.7 0.23 Sodium Hypochlorite 7.5 2.5 Sodium Hydroxide 1.32 0.44 Perfume qs qs Stabiliser (Sodium Metaperiodate) 0.024 0.008 Softened Water balance balance Viscosity (LV, Spindle 2, Speed 6rpm) 540cps 230cps Example 3.

Neat Product Diluted Product Myristyl Dimethyl Amine Oxide 3.36 1.12 Xylene Sulphonate 0.72 0.24 Secondary Alkane Sulphonate 0.7 0.23 Sodium Hypochlorite 7.5 2.5 Sodium Hydroxide 1.32 0.44 Perfume qs qs Stabiliser (Sodium Metaperiodate) 0.024 0.008 Softened Water balance balance Viscosity (LV, Spindle 2, Speed 6rpm) 181Scps 140cps Example 4.

Neat Product Diluted Product Myristyl Dimethyl Amine Oxide 3.36 1.12 Alkyl Carboxylate 0.384 0.128 Secondary Alkane Sulphonate 0.7 0.23 Sodium Hypochlorite 7.5 2.5 Sodium Hydroxide 1.32 0.44 Pefume qs qa Stabiliser (Sodium Metaperiodate) 0.024 0.008 Viscosity (LV, Spindle 2, Speed 6rpm) 290cps 400cps Example 5.

Neat Product Diluted Product Myristyl Dimethyl Amine Oxide 3.36 1.12 Sodium laurate 0.15 0.05 Secondary Alkane Sulphonate 0.7 0.23 Sodium Hypochlorite 7.5 2.5 Sodium Hydroxide 1.32 0.44 Perfume qs qs Stabiliser (Sodium Metaperiodate) 0.024 0.008 Softened Water balance balance Viscosity (LV, Spindle 2, Speed 6rpm) 352cps 150cps 1) Lauryl Amine Oxide = Empigen OB 2) Lauryl Ether Sulphate = Manro NES28 3) Alky] Carboxylate = Akypo TFC 4) Xylene Sulphonate = Manro SXS30 5) Sodium Laurate = Neutralised form of lauric acid.

6) Myristyl Amine Oxide = Empigen OH25D 7) Alkyl Sarcosinate = Hamposyl L30 8) Secondary Alkane Sulphonate = Manro SAS30X

Claims

CLAIMS: 1. A liquid bleach composition comprising: (i) halogen bleach component; (ii) a surfactant thickening system which comprises: (a) a tertiary amine oxide surfactant; (b) a surfactant component comprising a secondary alkane sulphonate anionic surfactant; and (c) a solubilising anionic surfactant; (iii) electrolyte; and (iv) water.
2. A composition according to claim 1, wherein the bleach component is a chlorine based bleach component.
3. A composition according to claim 2, wherein the bleach component is sodium hypochlorite.
4. A composition according to claim 1, 2 or 3, wherein the solubilising surfactant is selected from the group consisiting of an alkoyl sarcosinate, a soap, an alkyl carboxylate, and xylene sulphonate.
5. A composition according to claim 4, wherein the solubilising surfactant is an alkoyl sarcosinate.
6. A composition according to any one of claims 1 to 5, wherein the total amount of tertiary amine oxide surfactant is from 2.5% to 5%, preferably from 2.6% to 4.35%, more preferably from 3.35% to 3.85% by weight of the total composition.
7. A composition according to either preceding claim, wherein the total amount of secondary alkane sulphonate anionic surfactant is less than 2%, preferably less than 1.17%, more preferably less than 0.93% and most preferably from 0.57% to 0.81% by weight of the total composition.
8. A composition according to any preceding claim, wherein the total amount of solubilising anionic surfactant is less than 2%, preferably less than 1.61%, more preferably from 0.89% to 1.25% by weight of the total composition.
9. A composition according to any preceding claim, comprising from 1% to 10%, preferably 2.5% to 9% by weight of the total composition of the surfactant thickening system.
10. A composition according to any preceding claim, comprising from 0.1% to 15% by weight of the bleach component.
11. A composition according to claim 7, comprising an amount of the halogen bleach sufficient to provide from 0.1% to 10% by weight of available halogen when diluted with two parts by weight of water to one part by weight of the composition.
12. A composition according to any preceding claim, wherein the total amount of electrolyte is from 0.1% to 15%, preferably from 5% to 10% and especially from 6% to 9% by weight of the total composition.
13. A composition according to any preceding claim, having a viscosity of from 50cp to 50,000cp, preferably from 100cp to 10,000cp, most preferably from 500cp to 1 ,OOOcp.
14. A composition according to any preceding claim, which when diluted with two parts by weight of water to one part by weight of the composition, produces a diluted product having a viscosity of from 25cp to 10,000cp, preferably from 50cp to 2,000cp, more preferably from 100cp to 500cp.