GB2331305A

GB2331305A - Fabric softening granules

Info

Publication number: GB2331305A
Application number: GB9824802A
Authority: GB
Inventors: Gerard James Delay; Stuart Walker; Mark Phillip Houghton
Original assignee: Robert McBride Ltd
Current assignee: Robert McBride Ltd
Priority date: 1997-11-12
Filing date: 1998-11-12
Publication date: 1999-05-19
Also published as: GB2331305A9; GB9723810D0; GB9824802D0

Abstract

Co-granules for use in laundry detergent compositions comprise an agglomeration of a fabric softening clay and a water soluble builder salt which together comprise 65% to 95% of the co-granules, said co-granules further comprising at least one organic fabric softening agent. The clay is preferably a smectite, the builder may be a phosphate, carbonate or bicarbonate, and the organic softening agent may be a quatemary salt. The laundry detergent may also comprise a betaine, a nonionic surfactant, sodium dodecyl benzene sulphonate, sodium sulphate, sodium silicate, sodium perborate, TAED, carboxymethyl cellulose, enzymes and water.

Description

2331305 1 FABRIC SOFTENING CO-GRANULES The present invention relates to

co-granules containing a fabric softening clay and being for incorporation in laundry detergent formulations. The invention also relates to laundry detergent formulations incorporating such co-granules.

Lamellar clays are well known as softening agents in laundry detergent formulations for domestic and industrial use. The performance of clays varies widely and depends on other formulation components, particularly the surfactant system since clay may be regarded as a "mud" and as such an efficient surfactant system will decrease its effectiveness. It is known that additives for the clay, e.g. amides, amines, and/or cationic surfactants, can improve performance of the clay.

Clays are often an off-white colour and are supplied as fine powders to aid dispersion and softening. They are therefore often co-granulated to improve whiteness and reduce "dustiness". Co-granules comprising clay and water soluble salt, are known. Thus for example EP-A-0 430 328 discloses a process for preparing high bulk density powders containing clay. This process comprises adding up to 35% by weight of a swelling clay to a particulate starting material comprised of:

(a) 10% to 70% for a non-soap detergent active material, and (b) at least 10% of water-soluble crystalline inorganic salts including sodium tripolyphosphate and/or sodium carbonate, the weight ratio of (a) to (b) being at most 2.5.

The mixture of (a) and (b) is treated in high-speed mixer/granulator having both a stirring action and a cutting action so as to produce a granular detergent composition or component having a bulk density of at least 550gl-1. We have however found that if a high speed mixer/granulator with a mixing and cutting action (hereinafter referred to as a high shear agglomerator) is used to agglomerate a mix of ingredients including a clay, the mixer rapidly becomes fouled with a clay coating, necessitating frequent cleaning and making continuous production difficult. Additionally, such a product tends to have a 2 --- 0 very dark grey appearance due to a multiplicity of small clay domains (resulting from the high sheer mixing/ogglomeration) and also due to absorption of water by the clay during agglomeration.

1 1 --0 Therefore, from a process efficiency point of view, it is desirable not to use high shear agglomeration techniques once clay has been incorporated into the detergent manufacturing process. One means of doing this is to produce a detergent base material using high shear agglomeration, and add the clay subsequently using a low shear mixer. This however leads to the problem that the clay is not agglomerated into the overall product giving rise to problems of dustiness, stickiness and grey appearance of the product. Such a product also frequently exhibits poor dispensing and solubility properties.

Therefore, it would be desirable to find a way in which a clay could be incorporated into a detergent formulation such that it is already in a granular form, but without subjecting it to high shear agglomeration with the other detergent ingredients. This cannot, however, be don simply by using a granular clay particle, as granular clays generally disperse only slowly and thus generally have poor softening properties.

According to the present invention there are provided co-granules comprising an agglomeration of a fabric softening clay and a water soluble builder salt which together comprise 65% to 95% of the co- granules, said co-granules further comprising at least one organic fabric softening agent.

The co-granules may have a mean particle size (by weight) of 300 to 1, 20ogm, more preferably 400 to 800 gm and more preferably 400 to 50Ogm. The co-granules may be produced using a low or medium shear process. Such a process produces co-granual with relatively large clay rich domains. The main domain size (by weight) is preferably 250 to 1,200 im, more preferably 350 to 800 gm and more preferably 350 to 500 gm.

, r, 3 Co-granules in accordance with the invention may be incorporated in liquid or solid laundry detergent formulations for imparting fabric softening properties thereto. Surprisingly, we have found that when such a co-granule is incorporated into a product, the fabric softening properties are enhanced, not only with respect to granular clays, and granular clay/organic softener mixes, but also compared to when fabric softening clays and/or organic softeners are incorporated directly into the product, as suggested in EP-A0430328.

Since after the co-granules are incorporated into a product, the product does not require high shear agglomeration, problems with fouling of apparatus are avoided. Since the clay is present in a co-granule, the product is not sticky and its dispensing and dispersion properties are improved. The product also has improved whiteness and the clay is less prone to segregation. The above combination of factors leads to increased case of manufacture and increased consumer acceptance.

Additionally the co-granules are less prone to segregation in the detergent formulation and may be produced whiter and are therefore more consumer acceptable.

The detergent formulation will comprise clay rich domains which are provided by the original co-granules or parts thereof (if there has been some "size breakdown" of the co-granules during the detergent manufacturing process).

The production of the detergent formulation from the co-granules may result in the formation of "agglomerated" structures in which the clay domain is "adhered" to other components of the formulation said "agglomerated" structures preferably comprise at least 80% by weight of the clay domain.

Generally the co-granule will comprise 25% to 70% of each of the clay and the builder salt, subject to the proviso that the co-granule comprises a total of 65% to 95% of the clay and the builder. More preferably, the cogranule comprises at least 35%, even more preferably at least 45% of the builder salt.

C, ' 1 4 Preferably the total amount of organic fabric softening agent incorporated in the co-granules is in the range 2% to 20% by weight, e.g. 5% to 15% by weight.

The co-granules may for example have a particle size of 500 to 1000 Rm with the clay being present therein as domains having a size of 300 to 750 gm.

The clay which is used in the formulation of the invention may be any one of the fabric softening clays having fabric softening properties used in laundry detergent formulations. Such clays are generally of the "lamellar type" and are such that the layers ttseparate" to become deposited on the garments being washed. The clay may for example be a smectite such as a Laponite, Bentonite, Montmorrillonite, Hectorite or Saponite. For example, the clay may be a Sodium Montmorrillonite, a Sodium Hectorite, a Sodium Saponite, a Calcium Montmorrillonite or a Lithium Hectorite.

Builder salts for use in the invention include at least one alkali metal phosphate, carbonate and/or bicarbonate. A particularly preferred builder salt is sodium triphosphate. Other builder salt which may be used is sodium carbonate.

The organic fabric softening agent is preferably at least one nitrogen containing compound having at least a degree of positive charge on the nitrogen atom.

One class of organic fabric softening agents are amides of the formula CnH2n+l - C-NCM1-12m+1.

0 where n and m are the same or different and are in the range 8 to 22, more preferably 10 to 20. If the alkyl groups are branched then they preferably include a chain of at least 8 carbon atoms.

__1 A particularly preferred amide for use in the invention is stearyl stearamide.

The amide is preferably present in an amount of 20% to 30% by weight of the clay.

Alternatively, or additionally, the organic fabric softening agent may be a quaternary ammonium salt having one long chain (e.g. C8-22) alkyl group and three short chain (e.g. Cl-4) alkyl groups. A suitable cationic surfactant is coco trimethyl ammonium chloride.

It is particularly preferred that the quaternary ammonium salt be used in combination with the above described amides in which case the quaternary ammonium salt may suitably be employed in an amount of up to 5%, more preferably 1 to 2%, by weight of the clay.

The amide and quaternary ammonium salt are preferably incorporated in the clay prior to the agglomeration with the builder salt and as such it is particularly preferred to use a clay such as commercially available under the name Annasoft (ex Akzo Nobel) which contains 25% stearyl stearamide and 1.5% cocotrimethyl ammonium chloride.

Further organic fabric softening agents which may be used include amine andlor amide functionalised silanes.

The clay, organic fabric softening agent (if not previously incorporated in the clay) and the builder salt may be agglomerated using a low speed, low shear mixer of the Lodige type but without the high speed cutting action. A binder such as disilicate (used as water glass) or a non-ionic surfactant (e.g. as available under the name Synperonic) may be used to assist agglomeration.

Co-granules in accordance with the invention may be incorporated in liquid, powdered or granular laundry detergent formulations. Typically the co-granules will be 6 used in such formulations in an amount of 5% to 20% by weight based on the total weight of the formulation.

The surfactant of the laundry detergent formulation may be of the anionic, nonionic or amphoteric type. Any of the surfactants widely used in laundry detergent formulations may be employed in the invention.

If an amphoteric surface active agent is used it may be present in the formulation in an amount of 0. 1 to 10% by weight, more preferably 0.5 to 5%, even more preferably 1 to 4% on the same basis.

The amphoteric surface active agent may be betaine surface active agent. Preferred betaines may be either of the formula (I) or (11).

R1 1 R3-N±CH2-COO- (1) 1 R2 R1 1 R3CON14CH2CH2C142N±CH2C00- 1 R2 (11) In the above formula, R 1 and R2 may be the same or different Cl -4 alky 1 groups whereas R3 is an alkyl group having 8-22 carbon atoms, more preferably 12 to 18 carbon atoms e.g. mixed C 10 to C 14.

7 The preferred betaine for use in the formulation of the invention is cocoamidopropyl betaine.

An alternative amphoteric surface active agent for use in the formulation of the invention is a glycinate of the formula R3NHCH2CO2H where R3 is as defined above.

Other suitable materials are as given in chapter 1 of "Amphoteric Surfactants", Lomax Ed, Marcel Decker, New York 1996.

If an anionic surface active agent is used then it is preferably present in the formulation in an amount of up to 10% even more preferably up to 5% by weight of the formulation. Examples of anionic surface active agents which may be employed include alkylary] sulphonates, alkyl sulphates, ether sulphates and ether carboxylates all as conventionally employed in laundry detergent formulations.

If a non-ionic surface active agent is used then it is preferably present in an amount of up to 15% by weight of the formulation, more preferably 2 to 10% on the same basis. Examples of non-ionic surface active agent which may be used include alkoxylates, ethylene oxide/propylene oxide block copolymers, alkanolamides (e.g. monoethanolam ides and diethanolarn ides), esters and amine oxides.

The laundry detergent may incorporate an activated bleaching system including a hydrogen peroxide precursor compound and a bleach activator.

The hydrogen peroxide precursor compound may, for example, be an inorganic persalt e.g. a perborate (in the monohydrate and/or tetrahydrate form), a percarbonate or a persulphate. The alkali metal salts of these compounds are preferred, particularly sodium and potassium salts. Alternatively in the case where the detergent formulation is in solid c 8 form, the bleaching agent may be a urea-hydrogen peroxide complex. In the case of a liquid formulation the hydrogen peroxide precursor compound may be hydrogen peroxide per se.

The amount of hydrogen peroxide precursor compound present in the formulation of the invention is preferably such as to provide 0.5% to 3% by weight active oxygen.

Suitable bleach activators are compounds containing aliphatic acyl groups.

It is preferred that the acyl group has two or three carbon atoms and is most preferably the acetyl group.

w r.

A particularly suitable activator is TAED (tetra acetyl ethylene diamine). Further examples of bleach activator which may be used include acetylated sugars and sugar derivatives, e.g. hexa acetyl sorbitol, hexa acetyl mannitol, penta acetyl glucose and octa acetyl sucrose. Particularly preferred are hexa acetyl sorbitol and hexa acetyl mannitol which may be used in admixture, e.g. as disclosed in EP-A-0 525 239. Further examples are compounds having nitrogen atoms in the basic carbohydrate skeleton, e.g. the peracetylated forms ofN-methyl gluxconamide, N-methyl glucamine and glucopyronosyl amine.

The amount of bleach activator incorporated in the detergent formulation of the invention will generally be in the range of 0.5% to 10% by weight of the total formulation, more preferably 1% to 8% and even more preferably 2% to 4% on the same basis.

The detergent formulations may comprise at least one enzyme.

The enzyme may, for example, be a protease, amylase, lipase or cellulase (or mixtures thereof) such as commonly used in detergent formulations. Examples of suitable enzymes are available under the names Opticlean, Savinase, Esperase; Termarnyl, Maxamayl, Lipomax, Lipolase; Celluzyme and Carezyme. The amount of 1 1 9 enzyme incorporated in the formulation will depend on activity but will typically be 0. 1 to 3%. This level is particularly suitable for Savinase 6.0T, Termamyl 60T, Celluzyme 0.7T and Lipomax.

It will be appreciated that the formulation may incorporate additional components as conventionally included in laundry detergent formulation. One example of such an additional component is a soap which may be used in an amount up to 5% by weight as a processing aid. Further examples include anti-foam agents, sequestrants (e.g. of the phosphonate type), whiteness maintenance agents (e.g. CMC, polyoxyethylene terephthalate, polyethylene terephthalate), colourants (e.g. dyestuffs), perfume, flow control agents (e.g. a sulphate) flow enhancer (e.g. a zeodite), pH regulators (e.g. a carbonate or bicarbonate), anti-corrosion agents, dye transfer inhibitors (e.g. PVP) and optical brighteners (e.g. Tinopal CBS- X and Tinopal DMS-X). These components may, for example, each be present in amounts up to 1% by weight of the formulation.

The invention will be further described with reference to the following nonlimiting Examples.

Example 1

Co-granules AJ of the following compositions were prepared and sieved to have an average particle size of 500 gm.

A) Laundrosil DGA ex Sud Chemie - Comparative B) Laundrosil DGA (48%) co granulated with STP (48%) and 4% Sodium Disilicate introduced as water glass. - Comparative C) Armasoft EN 1 OOC ex Akzo Nobel - Comparative D) Armasoft EN I OOC Clay 75%,co granulated with Sodium Disilicate 21% and 4% Sodium Disilicate introduced as water glass.

C, t, Z1 c 1 1 - 1. ' 1 E) Armasoft EN I OOC Clay 75%, co granulated with Syriperonic A7 25% - Comparative.

F) Annasoft EN 1 OOC Clay 42%, co granulated with STP 40% & Sodium Disilicate 18% introduced as water glass.

G) Armasoft EN I OOC Clay 42%, co granulated with STP 46% & 12% Syriperonic A7 H) Armasoft EN I OOC Clay 42%, co granulated with STP 45.8% & 12% Synperonic A7 + 0.2% DMS-X (ex Ciba Speciality Chemicals) fluorescent whitening agent.

1) Armasoft EN I OOC Clay 42%, co granulated with STP 42% & 12% Synperonic A7 + 4% Titanium dioxide powder of average particle size 10Ogm.

J) Armasoft EN lOOC Clay 42%, co granulated with Sodium Carbonate 46% & 12% Synperonic A7.

K) Armasoft WA powder clay 50% aggregated under pressure with 50% STP. Laundrosil is a Montmorillonite clay.

Annasoft is a Montmorillonite clay with 25% Stearyl Stearamide and 1.5% Cocotrimethyl Ammonium Chloride.

Whiteness of the co-granules A4 was measured by a Harrison reflectometer using the Z- scale with ultra violet filter to exclude fluorescent effects and Z+ to include fluorescent effects measurement scale as defined in R. Mc Donald, Colour Physics for Industry, SDC Press, Bradford, 1987. (Higher Z is whiter appearance).

1 .e 11 Granule Z_ Z+ A 58 58 B 73 73 c 56 56 D 58 58 E 71 71 F 59 59 G 76 76 H 71 97 1 87 87 j 74 74 K 72 72 1 ' 0 n.5 0 0 J 3 12 Example 2

Detergent formulations IA to IK were prepared as follows 1 Formulation IA and IC IB and IK IF, IG, 1H, ID and 11 and U IE Synperonic A7 1.5% 1.5% 1.5% 1.5% Nonionic surfactant ex ICI Dodecyl benzene 3.6% 3.6% 3.6% 3.6% sulphonate sodium salt Sodium Carbonate 21% 21% 21% 21% Sodium Phosphate 20% 20% 20% 20% Sodium Sulphate 22% 22% 22% 220% Sodium Silicate 1.5% 1.5% 1.5% 1.5% Sodium Perborate 11.5% 11.5% 11.5% 11. 5 j/-.

Tetra acetyl 1.5% 1.5% 1.5% 1.5% ethylene diamine Softening granules 7% AorC Softening granules 14% B or K Softening granules 16.6% F, G, H, 1 or J Softening granules 10.5% D or E Water 5% 5% 5% 5% Carboxymethyl 1.5% 1.5% 1.5% 1.5% cellulose Enzymes and other to 100% to 100% to 100% to minor ingredients 100% 13 Further detergent formulations 2A to 2K were prepared as follows Formulation 2A and 2C 2B and 2K 2F, 2G, 2H 21 and 2J 2D and 2E Synperonic A7 Nonionic 3% 3% 3% 3% surfactant ex ICI Synperonic A3 1% 1% 1 % 1% Nonionic surfactant ex ICI Cetyl amido propy) 1.6% 1.6% 1.6% 1.6% betaine surfactant ex Akzo Nobel Sodium Carbonate 22 22 22 22 Sodium Phosphate 27% 20% 20% 20% Sodium Sulphate 27% 27% 27% 27% Sodium Silicate Sodium Perborate 11.50% 11.5% 11.5% 11.5% Tetra acetyl ethylene 1.5% 1.5% 1.5% 1.5% diamine Softening granules A or 7% c Softening granules 14% B or K Softening granules F, G, 16.6% H, 1 or J Softening granules D or 10.5% E Water 5% 5% 5% 501, Carboxymethyl cellulose 1.5% 1.5% 1.5% 1.5% Enzymes and other to 100% to 100% to 100% to 100% minor in-redients 0 14 A further detergent formulation I L was prepared by mixing formulation I K in a high shear blender for ten minutes to reduce the domain size. A further formulation 2L was prepared in the same manner from formulation 2K.

All of the above formulations were tested for their fabric softening performance.

Cloths for softening where prepared by scouring and desizing the cloths using three washes at 951C for cotton articles and 3 at 6WC for polycotton (50/50) and polyester articles. The cloths were desized using a mixture of the following composition.

Component Percentage Sodium Disilicate 48% Synperonic A7 ex ICI 2% Sodium Triphosphate 50% This leaves pure coarse cotton base on which to evaluate softening benefits.

The test formulation was dosed at 150g per wash. Washes were carried out at 40'C in a Hotpoint Ultima 1200 washing machine using 30Opprn Calcium carbonate water hardness. The wash loads were made up to 2.5kg weight using a clean cotton ballast. After washing, a panel of twenty people were asked individually to rank the cloth pieces in order of softness (1=softest).

The results were as follows Formulations 1AAL Granule Softness ranking Average Domain Size A 12 None B 11 450 gm c 10 50 gm D 7 470 gm E 9 455 gm F 5 450 gm G 1 425 gm H 1 430 gm 1 1 475 gm j 6 415 gm K 1 430 gm L 7 100 gm 1 16 Formulation 2A-2L Granule Softness ranking A 12 B 11 c 10 D 8 E 7 F 5 G 1 H 1 1 1 j 6 K 1 L 8 Comparison between Formulations 1 and 2 Formulation Softness ranking IA 7 2A 7 ID 5 2D 6 li 3 2J 4 IG 2 2G 1 17 Conclusions

Co-granules comprised of a clay, a soluble salt and an organic fabric softening agent have improved softening capability. The best softening salt is STP but other salts, carbonate and silicate proved to be effective. It may be expected that other analogous salts to these will also be effective. Cogranulation was ineffective in improving an 'inactivated clay' (i.e. one which does not contain an organic fabric softening agent). Formulations based upon anionic surfactant at low levels were the most effective in utilising the softening benefit of a cogranulated clay. Cogranulation also improved product whiteness especially if specific whitening agents are included. The use of a surfactant granulation aid gives more effective softening and a whiter granule than using an inorganic binder.

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Claims

1. Co-granules comprising an agglomeration of a fabric softening clay and a water soluble builder salt which together comprise 65% to 95% of the cogranules, said cogranules further comprising at least one organic fabric softening agent.

2. Co-granules as claimed in claim 1 having a mean particle size by weight of 300 to 1,200 gm more preferably 400 to 800 tm and most preferably 400 to 500 gm.

3. Co-granuies as claimed in claim 1 or 2 comprising 25% to 70% by weight of the clay.

4. Co-granules as claimed in any one of claims 1 to 3 wherein the clay is of the Lamellar type.

Co-granules as claimed in any one of claims 1 to 4 wherein the clay is a smectite.

6. Co-granules as claimed in any one of claims 1 to 5 wherein the clay is a Laponite, Bentonite, Montmorrillonite, Hectorite or Saponite.

7. Co-granules as claimed in claim 6 wherein the clay is a Sodium Montmorrillonite, a Sodium Hectorite, a Sodium Saponite, a Calcium Montmorrillonite or a Lithium Hectorite.

8. Co-granules as claimed in any one of claims 1 to 7 comprising 25% to 75% by weight of builder salt.

9. Co-granules as claimed in claim 8 comprising 35% to 70% by weight of builder salt.

10. Co-granules as claimed in claim 9 comprising 45% to 70% by weight of builder salt.

,0.

r.

1 19

11. Co-granules as claimed in any one of claims 1 to 10 wherein the builder salt comprises at least one alkali metal phosphate, carbonate andlor bicarbonate.

12. Co-granules as claimed in claim 11 wherein the builder salt is sodium triphosphate.

13. Co-granules as claimed in claim 11 wherein the builder salt is sodium carbonate.

14. Co-granules as claimed in any one of claims 1 to 13 comprising a total of 2% to 20% by weight of organic fabric softening agent.

15. Co-granules as claimed in claim 14 comprising a total of 5% to 15% by weight organic fabric softening agent.

16. Co-granules as claimed in any one of claims 1 to 15 wherein the organic fabric softening agent is a nitrogen containing compound having at least a degree of positive charge on the nitrogen atom.

- 1 1

17. Co-granules as claimed in claim 16 wherein the organic fabric softening agent is an amide of the formula Cril712n+ 1 - C-NCmH2m+ 1 1 1 0 where n and m are the same or different and are in the range 8 to 22.

18. Co-granules as claimed in claim 17 wherein n and m are the same or different and are in the range 10 to 20.

19. Co-granules as claimed in claim 17 or 18 wherein the amide is present in an amount of 20% to 30% by weight of the clay.

20. Co-granules as claimed in any one of claims 17 to 19 wherein the amide is stearyl stearamide.

21. Co-granules as claimed in claim 16 wherein at least part of the organic fabric softening agent is provided by a quaternary ammonium salt having one C8-22 alkyl group and three C 1-4 alkyl groups.

22. Co-granules as claimed in claim 21 wherein the quaternary ammonium salt is present in an amount of up to 5% by weight of the clay.

23. Co-granules as claimed in claim 21 or 22 wherein the quaternary ammonium salt is coco trimethyl ammonium chloride.

24. Co-granules as claimed in any one of claims 16 to 23 wherein the fabric softening agent comprising 20 to 30% of an amide as defined in claim 16 and 1 to 2% of the quaternary ammonium salt as defined in claim 19, these percentages being based on the weight of the clay.

21

25. Co-granules as claimed in any one of claims 1 to 24 which incorporate a binder.

26. Cogranules as claimed in claim 25 wherein the binder is a disilicate or a nonionic surfactant.

27. A laundry detergent formulation having fabric softening properties comprising at least one surface active agent and being prepared from cogranules as claimed in any one of claims 1 to 26, said formulation including claim rich domains having a mean domain size by weight of 250 to 1,200 gm more preferably 350 to 800 gm and most preferably 350 to 500 gm.

28. A formulation as claimed in claim 27 wherein the co-granules comprise 5% to 20% by weight based on the total weight of the formulation.

29. A formulation as claimed in claim 27 or 28 incorporating an amphoteric surface active agent.

30. A composition as claimed in claim 29 wherein the amphoteric agent is present in an amount of 0. 1 to 10% by weight based on the total weight of the formulation.

31. A composition as claimed in claim 30 wherein the amphoteric agent is present in an amount of 0.5 to 5% by weight based on the total weight of the formulation.

32. A composition as claimed in claim 31 wherein the amphoteric agent is present in an amount of 1 to 4% by weight based on the total weight of the formulation.

33. A formulation as claimed in any one of claims 29 to 32 wherein the amphoteric surface active agent is a betaine surface active agent.

34. A formulation as claimed in claim 33 wherein the betaine surface active agent is of the formula (1) or (11) -C, C - 1 1 1 c 1-1\ -1 '. (-, 22 RI 1 R3-N±CH2-COO- (1) 1 R2 RI i R3CONVICH2CH2CH2N±CH2C00- 1 (I1) R2 where RI and R2 are the same or different C1-4 alkyl groups are R3 is a C8-22 alkyl group.

35. A formulation as claimed in claim 34 wherein the betaine is cocoamidopropyl betaine.

36. A formulation as claimed in claim 27 or 28 incorporating an anionic surface active agent.

37. A formulation as claimed in claim 36 wherein the anionic surface active agent is present in the formulation in an amount of up to 10% by weight.

38. A formulation as claimed in claim 36 or 37 wherein the ionic surface active agent is an alkylaryl sulphonate, alkyl sulphate, ether sulphate or ether carboxylate.

C.

23

39. A formulation as claimed in any one of claims 27 to 38 incorporating a non-ionic surface active agent.

40. A formulation as claimed in claim 39 wherein the non-ionic surface agent is present in an amount up to 15% by weight of the formulation.

41. A formulation as claimed in claim 39 or 40 wherein the non-ionic surface active agent is an alkoxylate, ethylene oxide/propylene oxide block copolymer, alkanolamide, ester and amine oxide.