Field of the Invention

The present invention relates to detergent compositions based on hypochlorite.

Background of the Invention

The present invention relates to the use of hypochlorite comprising compositions.

A disadvantage of using hypochlorite-comprising compositions is that such compositions have a strong odour related to them. This odour is due to the presence of bleach in the composition. The consumer considers this a highly undesirable feature of such compositions.

The alodour is noticeable in all compositions comprising hypochlorite. Indeed, even when only small concentrations of hypochlorite are present in a composition the odour is noticeable.

Additionally, not only do the compositions themselves have an undesirable odour, all articles and surfaces treated with a hypochlorite-comprising composition suffer from malodour as well.

Furthermore, it has been found that after using such a hypochlorite-comprising composition, the consumer's person may also be subject to a residual bleach odour, particularly on the hands. This odour may remain for a number of hours, in spite of washing.

In addition the odour is also very persistent and the odour tends to linger at and around the point of application. Often the odour can still be detected a number of hours after the composition has been used. The pungent odour is considered unpleasant by the consumer and indeed in some cases even nauseous.

Thus, it is an object of the present invention to formulate a hypochlorite-comprising composition with reduced bleach odour.

It has now been found that the use of a hypochlorite- compatible short chain surfactant in hypochlorite- comprising compositions reduces bleach odour.

A further benefit is that the cleaning performance of the composition according to the present invention can be boosted by the incorporation of said short chain surfactant.

The art describes many different hypochlorite-comprising compositions, for example US 4 282 109 discloses a thickened bleach composition comprising hypochlorite and a thickening amount of a surfactant blend, comprising amine oxide CIQ- IS and alkyl sulphate Cg-C-j_2-

EP 274 885 discloses thickened bleaching compositions comprising alkali metal hypochlorite and straight chain C 4 a ine oxide with a mixture of branched and straight chain C_5 amine oxide. There is no mention of short chain surfactants.

EP 233 666 discloses a process for the manufacture of thickened bleaching compositions comprising hypochlorite, a hypochlorite-soluble surfactant and an alkali metal salt of a fatty acid.

DE 28 37 880 covers bleaching compositions comprising alkali metal hypochlorite and mixtures of branched and linear amine oxides of varying chain length, (C5-C17 ₎ for increased viscosity.

EP 30 401 covers thickened bleaching compositions comprising hypochlorit- ^■ - and a certain number of product characteristics including pH and viscosity. Mixtures of Cg- C 8 amine oxides and fatty acids are preferred as thickening agents. No other surfactants are disclosed.

Co-pending European applications Nos: 93202187.6 and 93202186.8 disclose short chain surfactants.

Summary of the Invention

The present invention is the use of a hypochlorite- compatible short chain surfactant comprising a hydrophobic and a hydrophilic portion, wherein the chain length of said hydrophobic portion is Cg to C-j_o for reduced bleach odour in hypochlorite-comprising compositions.

All amounts, percentages and ratios are given by % weight of the total composition unless otherwise stated.

Detailed Description of the Invention

The present invention is the use of a hypochlorite compatible short chain surfactant comprising a hydrophobic and a hydrophilic portion, wherein the chain length of said hydrophobic portion is Cg to C-J_Q, to reduce bleach odour in hypochlorite-comprising compositions.

Thus an essential ingredient for use herein is hypochlorite. Preferably the hypochlorite is an alkali metal hypochlorite. Although alkali metal hypochlorites are preferred other hypochlorite compounds may also be used herein and can be selected from calcium and magnesium hypochlorite. Compositions according to the present invention comprise said hypochlorite compound such that the content of active chlorine in the composition is from 0.1% to 10%, preferably from 0.5% to 6%, more preferably from 1% to 5.5% and most preferably from 1% to 4%.

It has now been found that the bleach odour associated with hypochlorite-comprising compositions and areas and surfaces treated therewith, can be reduced by the use of a short chain surfactant or mixtures thereof in said compositions.

Thus, according to the present invention another essential ingredient is a hypochlorite compatible short chain surfactant. Said short chain surfactant comprises a hydrophobic portion and a hydrophilic portion, wherein the chain length of the hydrophobic portion is Cg to C^Q.

All surfactants have in common that they comprise a hydrophobic portion and a hydrophilic portion. By short chain surfactant, it is meant herein surfactants which comprise a Cg-C _] _o alkyl chain as their hydrophobic portion. Such short chain surfactants are accordingly those conventionally used in this field, but with a shorter alkyl chain, and can be of any type. Accordingly, suitable short chain surfactants for use herein include ^c 6~ ^c 10 alkyl sulfates (C -CioSC- ) , alkyl ether sulfates (Cg-

C_o (OCH CH2)eS04) , alkyl sulphonates , alkyl succinates (Cg-C-]_o ^OOCCH 2 ^CH 2 ^cooz ) / alkyl carboxylates (Cg- C ₁₀ COOM) , alkyl ether carboxylates (Cg-Cio (OCH ₂ CH ) _e COOM) , alkyl sareosinates (Cg-C--_oCON(CH3)R) , alkyl sulpho succinates (Cg-C ₁₀ OOCCH(SO ₃ M)CH ₂ COOZ) , amine oxides (Cg-CioRR'NO) , and betaines (Cg-C ₁₀ N ⁺ (CH ₃ ) CH ₂ COO-) . In the formulae in brackets, e is from 0 to 20 and Z is M or R, M is H or any counterion such as those known in the art, including Na, K, Li, NH4, amine. R and R ¹ are preferably 1-C3, most preferably methyl. All these surfactants are well known in the art. According to the present invention the compositions may comprise any of the above surfactants alone, or any combination thereof, depending on the end use envisioned.

Preferred short chain anionic surfactants for use herein are alkyl sulfates (Cg-CιoS04) and alkyl sulphonates (Cg-CιoSθ3) . Most preferred are the C6-C8 alkyl sulfates and sulphonates. Such short chain anionic surfactants can be made by well known sulphation or sulphonation processes followed by neutralization, but said anionic short chain surfactants are more conveniently commercially available, for instance from Rhone Poulenc under the trade name Rhodapon® OLS, or from Witco under the trade name Witconate . According to the present invention said short chain surfactants may be used alone or in combination.

Preferred short chain surfactant for use herein is octyl sulphate. Suitable short chain surfactants for use herein are hypochlorite compatible. According to the present invention, the compositions comprise from 0.01% to 8% of short chain surfactants, preferably from 0.02% to 7% more preferably from 0.1% to 4% and most preferably from 0.5% to 3%.

According to the present invention the composition may further comprise a number of additional ingredients. Suitable optional ingredients include other hypochlorite-compatible long chain surface actives including alkyl sareosinates, alkyl ether sulphates, paraffin sulphonates and amine oxides.

The compositions according to the present invention may also comprise a number of other additional ingredients such as hypochlorite stable and soluble colourants and perfumes, and hydrotopes such as sodium xylene sulphonate

According to the present invention, an optional requirement of the compositions is that the pH is as is of from 9 to 14, preferably greater than 10, more preferably greater than 11, most preferably greater than 11.5. This is achieved by the addition of from 0.1% to 2% of a caustic alkali. Suitable caustic alkalis for use herein include sodium and potassium hydroxide.

In one embodiement of the present invention it is important to maintain the pH of the compositions of the present invention in the alkaline range throughout use. Thus, according to the present invention the compositions may further comprise a buffering system to buffer the pH of the present compositions throughout use. It is also suspected that the buffering of the hypochlorite compositions reduces harshness to hands. Particularly useful to be used herein are silicate or carbonate salts, or mixtures thereof. The preferred alkali metal salts of silicate and carbonate are sodium silicate and sodium carbonate, both of which are commercially available, or mixtures thereof. Preferred compositions herein use a mixture of sodium carbonate and sodium, silicate. The compositions herein comprise up to 5% by weight of the total composition of sodium carbonate, preferably from 0.2% to 5%, more preferably from 0.5% to 3%, and preferably up to 3% by weight of the total composition of sodium silicate, preferably from 0.02% to 3%, more preferably from 0.04% to 3%.

According to the present invention the compositions may be used for a variety of purposes, such as bleaching hard surfaces and in laundry applications including hand washing as well as washing with automatic washing machines. The

compositions according to the present invention can be illustrated by the following examples.

Examples

Compositions A B C D E F G

Q- . amine oxide 3 3 3 3 4 4 3.2 octyl sulphate 3 4 3 4 4 3 3 ^c χ ₂ alkyl sulphate 2 2 3 3 2 3 3

Sodium hypochlorite 1. .6 1. 6 1. 6 1. 6 1. 6 1.6 1.6

Fatty acid (Coconut/ 0. 9 0. 9 0. 9 0. 9 0. 9 0.9 0.9 palm kernel)

Sodium hydroxide 0. 8 0. 8 1 1 1 1 1

Water and minors (balance)

Compositions G H I J K L

C]_2 amine oxide 2. 7 2.7 2. ,7 2. 4 2.4 1.6 octyl sulphate 2 2 2 2 2 1

Sodium hypochlorite 2 2 2 2 2 2

Fatty acid (Coconut/ - - - - 1 1.6 palm kernel)

Sodium hydroxide 1. 3 1.3 1. .3 1. ,3 1.3 1.3

Water and minors (balance)

Compositions M N octyl sulphate 3 3 3 3 2 3

Cχ4 amine oxide 3 3 3 3 / /

C]_4 alkyl sulphate 1.5 1.5 1.5 1.5 / / palm kernal fatty acid 0.8 0.8 0.8 0.8 / / sodium hypochlorite 2 3 4 5 5 5 sodium hydroxide 1.3 1.3 1.3 1.3 0.7 0.7

silicate 0 . 4 0 . 4 0 . 4 0 . 4 1 /

Carbonate / / / / 1 1 perfume 0 . 3 0 . 3 0 . 3 0 . 3 / / water and minors (balance)

The compositions according to the present invention may be tested for bleach odour using the following method:

The method is comparitive and thus only one composition's odour respective to another may be tested at any one time. The odour is evaluated using the following scale:

0 No bleach odour

1 Very weak bleach odour

2 Weak bleach odour

3 Moderate bleach odour

4 Strong bleach odour

5 Very strong bleach odour

Hard Surface odour evaluation:

The hypochlorite comprising composition is diluted, 1 part to 25 parts water. 5ml of the solution is pipetted into a glass container. A dry sponge is placed in the container and left until all the solution has been soaked up. A tile is then wiped lightly five times with the sponge. The tile is then placed in another glass container with the lids slightly ajar. The tile is then smelt without removing it from the glass container at intervals of 0, 15, 30, 45, 90 and 120 minutes. A rating for the odour is then given using the above scale. The test is then repeated.

Residual odour on hands evaluation:

The hypochlorite comprising composition is diluted, 1 part to 25 parts water. Sufficient solution is made to fill a container to a level to submerge the hands and wrists of the

tester. The tester places one hand into each of the solutions to be tested for 30 seconds. The hands are then removed from the solution and placed under cold running water for 5 seconds. Each hand is patted dry with paper towels. The hands are ^' then smelt at time intervals of 0, 15, 30, 45, 60, 90 and 120 minutes. A rating for odour is then given using the above scale. After 3 hours the hands are rewetted and smelt. The test is then repeated.

Neat odour on hands evaluation

5grms of the hypochlorite-comprising composition is placed on a damp sponge. The fingers of the tester are placed on the sponge for 5 minutes. The hands are then removed from the sponge and left to dry on a clean, dry and flat surface for 5 minutes. During this time the hands are kept stationary. The hands are then smelt at time intervals of 0,15, 30, 45, 60, 90 and 120 minutes. An odour rating is then given using the above scale. The test is then repeated.

The result for the neat odour on hands evaluation test for composition G compared to an identical composition wihtout the short chain surfactant is shown in figure I.

All the compositions according to the examples above have reduced bleach odour.