GB2176799A - Detergent composition in paste form - Google Patents

Abstract

A detergent paste comprises from 1% to 45% by weight of detergent, from 1% to 50% by weight of detergent builder, has a viscosity in the range 5,000 to 20,000 poise and contains alumino-silicate which is formed in situ during the preparation of the paste. The presence of the alumino-silicate stabilises the paste against separation of the components during storage or use.

Description

SPECIFICATION Detergent compositions Field of the invention This invention relates to improved built detergent pastes. These products, usually intended for the washing of fabrics and cleaning of surfaces, are required to have properties which allow efficient manufacture and performance of the required functions.

In particular the pastes must be stable over a period of time so that their properties remain constant during storage and subsequent use. The product will usually be sold commercially in a sachet or closed pot but there is, in general, no restriction on the packaging which can be used for these products.

General description of the invention: The invention provides built detergent pastes comprising from about 1%, preferably from about 5%, to about 45% by weight of detergent active material and from about 1%, preferably from about 5% to about 50% by weight of detergency builder. The homogeneous detergent paste will normally have a viscosity at 25"C in the range from 5,000 poises to 20,000 poises, preferably 8,000 poises to 16,000 poises.

Such pastes are designed to be used for hand washing of fabrics and other materials eg.

dishes and cooking utensils but can be applied to the surface to be cleaned with the aid of a cloth or other suitable hand implement. The pastes of the invention may be used as a base for a scouring composition. The pastes can also be formulated to be dispensed in washing machines. Such pastes may have a tendency to destabilise during storage or use by separation of the components within the mass of the product.

Such pastes are required to demonstrate stability even when subjected to temperature cycling and storage for a period.

The present invention provides a means of structuring the homogeneous detergent paste to improve the stability. This objective is achieved by generating an alumino-silicate in situ during the manufacture of the detergent paste. The alumino-silicate will generally form from about 0.5% to about 7% by weight of the final product with the commercial level being selected to provide the necessary stability. It must be appreciated that the stability of any product is dependent on the components and processing to which the product has been subjected. The benefit provided by the invention will be dependent on the formulation to which it is applied. The alumino-silicate formed allows the viscosity of the homogeneous paste to be selected within an appropriate commercial range.

The precursors for the generation of alumino-silicate during processing are not critical but it will be necessary to select the precursors which provide the desired in situ reaction given the conditions of manufacture. In general it is necessary to mix the alumino-silicate precursors in the presence of excess alkali to ensure the desired reaction occurs without aluminium ions remaining in the product. A preferred precursor system is a soluble aluminium salt, for example aluminium sulphate, and sodium silicate, the latter being usable in the neutral or alkaline form. Other aluminium salts which can be used are the chloride and nitrate. In general the precursors will be used in approximately stoichiometric amounts but some variation is allowable provided the aluminium precursor is not in excess. The balance of SiO2:AI203 in the precursors will usually be in the range 1:1 to 2:1 molar.

The present invention also provides a process for preparing a built detergent paste comprising from about 146, preferably from about 5%, to about 45% by weight of detergent active material and from about 1%, preferably from about 5%, to about 50% by weight of detergent builder material and having a viscosity at 25"C in the range of from 5,000 to 20,000 poises, preferably from 8,000 to 16,000 poises, the process comprising generating an alumino-silicate in situ during the manufacture of the detergent paste. Preferably alumino- silicate is generated in an amount above 0.5% by weight and in an amount not above 7%, more preferably not above 5%, by weight with respect to the total composition.The process preferably comprises admixing a soluble aluminium salt with alkaline or neutral e.g. sodium silicate in the presence of the detergent active material and the detergency builder in an alkaline environment. Suitably the alkaline environment is provided by excess alkali e.g. sodium carbonate employed in the previous neutralisation of the detergent active material which is preferably alkyl benzene sulphonic acid.

The aluminium salt is preferably employed in an amount measured as the anhydrous salt between 2.5 and 8.0% by weight with respect to the total composition. The preferred aluminium salt is aluminium sulphate. The silicate is preferably employed in an amount measured as the anhydrous salt between 1.6 and 5.1% by weight with respect to the total composition. The preferred silicate is alkaline sodium silicate. The aluminium salt and the alkaline or neutral silicate are preferably admixed in-situ in the detergency active material and builder mix at a temperature within the range 55 to 70"C, preferably 60 to 70"C.

Components of the formulation: Detergent active and builder components are well characterised in detergent technology literature. 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 may be found in the general classes of anionic, nonionic, amphoteric, betaine and zwitterionic actives. Specific examples of suitable detergent actives are primary alcohol sulphates, linear alkyl benzene sulphonates, branched alkyl benzene sulphonates, alkane sulphonates, secondary alcohol sulphates, alkyl sulphates, olefin sulphonates, ethoxylated alcohols, monocarboxylic acid salts and fatty acid ester sulphonates.

Examples of builder components are the water soluble phosphate salts eg. sodium tripolyphosphate, pyrophosphate and orthophosphate; water soluble carbonates e.g. sodium carbonate and organic builders e.g. sodium nitrilo triacetate, sodium tartarate, trisodium carboxy-methyl oxysuccinate, sodium oxydisuccinate and sodium sulphonated long chain monocarboxylic acids.

Other ingredients, for example silicates e.g. sodium alkaline silicate, starch, sodium carboxymethyl cellulose, enzymes, colouring materials, fluorescers, opacifiers, germicides, lather boosters eg. coconut ethanolamide, perfumes, bleaching agents, fillers e.g. sodium sulphate, talc, calcite and bentonite, and electrolytes (other than those listed previously) to provide the necessary electrolyte concentration, are optionally present.

Prior Literature: UK 2099013 (Unilever) describes improving detergent bar product properties by generating alumino-silicate in situ during processing. Examples of specifications described detergent pastes are US 4409136 (Cheng/Colgate Palmolive) and US 4115308 (Guerry/Procter and Gamble).

Examples of specifications describing the use of alumino-silicate as a builder material and as an ion-exchange material are respectively FR 2287503 and GB 2001944, both in the name of Henkel.

Specific Description of the Invention: Detergent pastes were prepared and subjected to tests to determine the stability improvement obtained when alumino-silicate was formed in the product during processing.

EXAMPLE I A paste intended for fabric washing and having the formulation below was prepared.

Sodium alkyl benzene sulphonate 31% Sodium pyrophosphate 6% Sodium carbonate (remaining from neutralisation) 0.8% Total water 49% Sodium alumino-silicate 5% Remainder eg. salts, non detergent organic matter, fluorescer, perfume and dye.

Water (290 gms) was heated to about 70"C in a reactor vessel and then sodium pyrophosphate (45 gms) sodium carbonate (39 gms) and caustic soda (31 gms) were added to the hot water with rapid stirring until maximum solution was obtained. An alkyl benzene sulphonic acid (MW324, 2669) was added slowly with stirring over a 20 minute period to the alkaline solution prepared previously. The viscosity of the mixture increased during this addition and increased stirring was necessary to ensure good mixing efficiency. After the neutralisation period the temperature was about 70"C.

Alkaline silicate (48% by weight, 589) was then added and the mixture stirred for 10 minutes.

Aluminium sulphate hydrate powder (709) was then added and the mixture stirred for a further 5 minutes. During this period the viscosity of the solution increased. The minor components i.e.

fluorescer, dye and perfume were added followed by 15 minutes rapid stirring. The whole paste was then cooled and was ready for packaging; it had a viscosity of 16,000 poises at 25"C.

EXAMPLE II A paste intended for dishwashing was prepared.

Water (2909) was heated to about 70"C in a reactor vessel and then soda ash (122.59) and stirred for 5 minutes. An alkyl benzene sulphonic acid (MW 324, 1849) was then added slowly with stirring over a 20 minute period to the alkaline solution prepared above. Sodium sulphate (769) was then added and the mixture stirred for a further 5 minutes. Alkaline silicate solution (48%, 359) was added next and after a further 10 minutes stirring aluminium sulphate hydrate (429). The mixture thickened after stirring for a further 5 minutes. Finally, the minor components i.e. pigment and perfume were added followed by a further 15 minutes rapid stirring. The whole paste was then cooled and, was ready for packaging, it had a viscosity of 10,5000 poises at 25"C.

The final product had the composition:alkyl benzene sulphonic acid 25% sodium carbonate 9% sodium sulphate 15% Sodium alumino-silicate 3% Water 47.25% Remainder-fluorescer, perfume, dye, non detergent organic matter.

The formulations described in Examples I and II did not show, after storage, water separation or mobility. The surface did not show cracking and/or curdling. During storage the products were subjected to 26 cycles of 6 hours at 42"C and 18 hours at 20 to 250C.

Example 111 A paste intended for fabric washing and having the formulation below was prepared.

Sodium alkyl benzene sulphonate 25% Sodium pyrophosphate 2.5% Sodium carbonate (remaining from neutralisation) 2.5% Total water 49% Sodium alumino-silicate 3% Remainder e.g. salts, non-detergent organic matter, fluorescer, perfume and dye.

The paste was prepared following the procedure described in Example 1. 300gms water, 19gms sodium pyrophosphate and 74gms sodium carbonate were used to form the alkaline solution to which 187gms of alkyl benzene sulphonic acid (m.w. 324) were added. Alkaline silicate (48% by weight 35gms) was added to the neutralised mixture, followed by 42gms aluminium sulphate hydrate powder.

The resulting paste had a viscosity of 16,500 poises at 25"C.

Example IV A paste intended for fabric washing and having the formulation below was prepared.

Sodium alkyl benzene sulphonate 25% Sodium pyrophosphate 1% Sodium carbonate (remaining from neutralisation) 5% Total water 47% Sodium alumino-silicate 3% Remainder e.g. salts, non-detergent organic matter, fluorescer, perfume and dye.

The paste was prepared following the procedure described in Example 1. 285gms water, 8gms sodium pyrophosphate, 92gms sodium carbonate, 187gms alkyl benzene sulphonic acid (m.w. 324), 35gms alkaline silicate (48% by weight) and 42gms aluminium sulphate hydrate powder were employed.

The resulting paste has a viscosity of 16,000 poises at 25"C.

Example IV A paste intended for fabric washing and having the formulation below was prepared.

Sodium alkyl benzene sulphonate 25% Sodium pyrophosphate 10% Sodium carbonate (remaining from neutralisation) 5% Total water 49% Sodium alumino-silicate 3% Remainder e.g. salts, non-detergent organic matter, fluorescer, perfume and dye.

The paste was prepared following the procedure described in Example I. 300gms water, 75gms sodium pyrophosphate, 92gms sodium carbonate, 187gms alkyl benzene sulphonic acid (m.w. 324), 35gms alkaline silicate (48% by weight) and 42gms aluminium sulphate hydrate powder were employed.

The resulting paste had a viscosity of 18,000 poises at 25"C.

Claims (10)

1. A stable detergent paste comprising from about 1% to about 45% by weight of detergent active material, from about 1% to about 50% by weight of detergent builder material, and having a viscosity in the range 5,000 to 20,000 poise characterised in that the product contains alumino-silicate formed in situ in an amount effective to stabilise the paste.

2. A paste according to claim 1 comprising at least about 5% by weight of detergent active material.

3. A paste according to claim 1 or 2 comprising at least about 5% by weight of detergent builder material.

4. A paste according to any preceding claim containing at least about 5% of phosphate builder.

5. A paste according to any preceding claim wherein the viscosity is above about 8,000 poises.

6. A paste according to any preceding claim wherein the viscosity is up to about 16,000 poises.

7. A paste according to any preceding claim wherein the alumino-silicate is present in an amount above 0.5% by weight of the product.

8. A paste according to any preceding claim wherein the amount of alumino silicate is not above about 7% by weight.

9. A paste according to any preceding claim wherein the amount of alumino-silicate is not above about 5% by weight.

10. Process for preparing a built detergent paste comprising from about 1% to about 45% by weight of detergent active material and from about 1% to about 50% by weight of detergent builder material and having a viscosity in the range 5,000 to 20,000 poises characterised by generating an alumino-silicate in situ during the manufacture of the detergent paste.