GB2162531A - Built laundry detergent bar - Google Patents

Abstract

A built laundry bar using fatty acid ester sulphonate as a component has at least 10% by weight of the cations present as potassium ions.

Description

SPECIFICATION Detergent compositions Field of the Invention This invention relates to improved built detergent bars. These products, which may be used for fabric washing and cleaning surfaces, should have certain properties to provide efficient performance of the required functions.

The invention is directed to improving the feel and lather characteristics of bars containing fatty acid ester sulphonate as the major detergent active.

Commercial built detergent bars contain detergent active and detergent builder materials together with optional components, for example abrasives, fillers, perfumes, alkaline salts, for example silicates, bleaching agents and enzymes.

General Description of the Invention The invention provides an improvement in built detergent bars comprising from about 5% to about 45% by weight of non-soap detergent active material and from about 5% to about 60% by weight of detergency builder.

The invention is specifically directed to detergent bar compositions containing at least about 10% by weight of fatty acid ester sulphonates; these detergent actives have the general formula R' CH(SO3M) COOR2 where R' is branched, eg derived from petroleum, or straight-chain alkyl group containing from 8 to 22 carbon atoms and R2 is an alkyl group containing 1 to 4 carbon atoms. M is a cation providing water-soluble properties for the detergent active and will usually be selected from ammonium, potassium and sodium. The bar composition may contain above about 20% of fatty acid ester sulphonates.

The applicants have found the use of a minimum amount of potassium ions in the cationic electrolyte content of a bar product containing fatty acid ester sulphonate improves the bar in use properties and foam properties. The presence of potassium ions also reduces the mush formed during use of the bars. At least about 10% by weight of the cationic species present must be potassium ions.

Preferably potassium ions form at least about 20% by weight of the cationic species in the bar, more preferably it is above about 40% by weight.

The potassium ions will usually be present in an amount not less than the stoichiometric equivalent to the fatty acid ester sulphonate anions present; preferably they will be present in 10% by weight excess and more preferably 20% by weight.

The upper practical level of potassium ions will usually be about 85% by weight of the cationic species because above this level the bar compositions may, dependent on the other components, exhibit poor process ability because of excess hardness.

The potassium ions may be introduced into the bar by any route, eg using the potassium detergent active salt, potassium salts of phosphate and silicate components and using potassium carbonate to neutralise the feedstock sulphonic acid. Potassium electrolytes, eg potassium sulphate, may also be used. However, the incorporation of potassium is most effective when all the potassium ion content, or at least that part of it equivalent to the fatty acid ester sulphonate anion, is introduced as the potassium fatty acid ester sulphonate during the manufacturing steps. Thus the neutralised active salt can be used as an initial ingredient or added during the mixing stages. Alternatively the sulphonic acid can be neutralised with potassium carbonate as the first stage in the manufacture.

The usual stages of detergent bar manufacture are followed in the examples with the ingredients being mixed in turn beginning with the neutralisation of sulphonic acid. After mixing, the compositions were extruded as bar form products.

Components Detergent active and builder components are well characterised in detergent bar technology.

These components are described in "Surface Active Agents" by Schwartz and Perry (Interscience 1949) and volume II by Schwartz, Perry and Berch (Interscience 1958). The detergent actives usable in the present invention in admixture with fatty acid ester sulphonates may be found in the general classes of anionic, nonionic, amphoteric, betaine and zwitterionic actives.

Specific examples of detergent actives are linear alkyl benzene sulphonates, alkane sulphonates, secondary alcohol sulphates, branched alkyl benzene sulphonates, alkyl sulphates, olefin sulphonates, monocarboxylic acid salts, ethoxylated alcohols and primary alcohol sulphates.

Examples of builder components are: water soluble phosphate salts, eg sodium tripolyphosphate, pyrophosphate and orthophosphate; water soluble carbonates, eg sodium carbonate; organic builders, eg sodium nitrilo triacetate, sodium tartrate, trisodium carboxymethyl oxysuccinate, sodium oxydisuccinate and sodium sulphonated long-chain monocarboxylic acids; ion exchange materials, for example alumino-silicates.

Other ingredients, for example silicates, eg sodium alkaline silicate, starch, sodium carboxymethyl cellulose, colouring materials, fluorescers, opacifiers, germicides, enzymes, perfumes, bleaching agents and fillers, for example sodium sulphate, talc, calcite and bentonite, are optionally present.

Specific Description of the Invention The invention will now be described with reference to specific examples of compositions.

Example I The improvement in lather efficiency was demonstrated using detergent compositions in soiled detergent liquors at a level of 29 per litre. The soiled liquor contained sebum at a level of 0.5 grammes per litre. The bar formulation contained: potassium fatty acid (coco) methyl ester sulphonate 25% sodium pyrophosphate 6% sodium tripolyphosphate 2% alkali metal carbonate 18% calcite filler 39% water 10% In bar (A) sodium carbonate was added as the alkali metal carbonate while in bar (B) the potassium salt was added.

The foam volume (millilitres) was measured after generation using both 20 and 40 French hard water and its subsequent stability was measured over a period of 5 minutes.

The foam was generated by manually shaking (fifty times) 25ml aliquots of detergent solution in stoppered graduated cylinders. The results are given in table I: Table I System/Product Foam Volume (mls) Stability at Time (minus) 0 1 2 3 4 5 2COFH/soiled: A 16.5 2.5 1.0 nil nil nil B 24.5 18.5 16.0 15.C 13.0 13.0 4COFH/soiled: Product dosage 2.0g/lit A 8.5 1.0 nil nil nil nil B 22.0 17.0 15.0 14.C 12.5 12.5 A bar of this formulation using only sodium as the cation had extremely poor properties.

Example II The foam volumes of bar formulations containing 20% by weight detergent active having relatively high potassium and sodium levels were compared.

The base formulation comprised: detergent active 20% sodium pyrophophate 6% sodium tripolyphosphate 2% alkalimetal carbonate 18% calcite filler 44% water balance The type of active present was varied to provide three test formulations, these were: C - potassium fatty acid (coco) methyl 20% sulphonate D - potassium fatty acid (coco) methyl 14% sulphonate sodium primary alcohol (coco) 6% sulphate E - potassium fatty acid (coco) methyl 14% sulphonate potassium linear alkyl (C12) benzene 6% sulphonate The proportion of potassium and sodium ions in the cationic species was varied by using appropriate potassium analogs of some of the sodium salts quoted, eg carbonate.The foam tests used the procedure of Example I with a formulation concentration of 1.75 g/lit of 20'FH water containing 0.5g/lit of sebum soil. The results are given in Table II.

Table II potassium foam volume (mls) Formulation in cations (8) initial After 1 min C 76.9 16.5 12.5 16.8 11.5 8.0 D 48.1 17.5 15.G 12.0 13.5 12.0 E 57.2 20.0 17.0 16.8 16.0 9.0 These results demonstrate an increase in potassium ions in the cationic species improves the foam properties.

Example 111 The improvement in bar in use properties with increase in potassium ion level was demonstrated by measuring the mush formed on the surface for the test formulations C, D and E. The mush was measured by using used weighed bars which were left overnight in a humidity cabinet (25 C/83% RH) in contact with water. The surface mush was scraped from the total bar surface and the bar weighed again after drying at 40"C for 24 hrs. The weight loss was noted.

Results are given in Table Ill.

Table III potassium Formulation in cations (%) weight loss (g) C 76.9 3.6 60.4 5.0 55.6 11.5 35.7 19.5 25.6 24.8 D 66.8 12.6 48.1 14.8 47.3 16.2 31.1 18.2 23.2 28.0 E 57.2 20.6 50.0 25.3 41.7 29.6 It is seen the amount of mush decreases with increase in potassium level.

Claims (10)

1. A built detergent composition in bar form containing from about 10% to about 45% by weight of non-soap detergent active material and from about 5% to about 60% by weight of detergency builder material wherein the composition contains at least about 10% by weight of detergent active with the general formula R'CH(SO3M)COOR2 where R' is an alkyl group containing 8 to 22 carbon atoms, R2 is an alkyl group containing 1 to 4 carbon atoms and M is a cation providing water soluble properties, characterised in that at least 10% by weight of the cationic species present is potassium ions.

2. A composition according to claim 1 wherein the potassium ions are present in an amount not less than the stoichiometric equivalent to the fatty acid ester sulphonate anions present.

3. A composition according to claim 1 or 2 wherein the potassium ions form at least about 20% by weight of the cationic species.

4. A composition according to any preceding claim wherein the potassium ions form at least about 40% by weight of the cationic species.

5. A composition according to any preceding claim wherein the potassium ions form not more than about 85% by weight of the cationic species.

6. A composition according to any preceding claim wherein the potassium ions form not more than about 60% by weight of the cationic species.

7. A composition according to claim 2 wherein the potassium ions are present in an excess of at least about 10% by weight over the stoichiometric equivalent to the fatty acid ester sulphonate ions.

8. A composition according to claim 7 wherein the excess is at least about 20% by weight over the stoichiometric equivalent.

9. A composition according to any preceding claim containing at least about 20% by weight of fatty acid ester sulphonate.

10. A process of manufacturing a composition according to any preceding claim wherein all the potassium ion content, or at least that part of it equivalent to the fatty acid ester sulphonate anion, is introduced at potassium fatty acid ester sulphonate during the manufacturing steps.