PH26058A - Detergent bars - Google Patents

Description

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I ? ' 26058

DETERGENT BARS 0p

This invention relates to detergent bars suitable for personal or fabric washing and to a process for the preparation of such detergent bars.

Conventionally a detergent bar based on soap for personal washing contains about 78% by weight TFM (total fatty matter), the remainder being water and other ingredients in small amounts e.g. colour, perfume and preservative. It is known to include also a small amount of inert solid non-detergent material of small particle size which is called a filler and which replaces some of the soap in the bar while retaining the desired firmness of the bar. Known examples of materials used as fillers include starch, kaolin and talc.

EP-A-93011 describes detergent bars containing 10% kaolin, and suggests that in a detergent bar up to 50% kaolin might be used, but no investigation was apparently made at any kaolin level beyond 10%. In India, sales of soap bars containing up to 20% kaolin have been made; typically the soap is soap base A of Comparative Example 1 below. GB-A-160892 describes a framed toilet bar

-2 - - $.3009 A containing between 20 and 50 weight % of 2 6 0 5 8 aluminium silicate, or a natural mineral substance containing a substantial proportions of hydrated aluminium silicate such as china clay, which is prepared by incorporating with melted fatty acids the said hydrated aluminium silicate and adding to the mixture the amount of alkali required for combining with the fatty acids for the production of soap.

Personal washing bars typically have a water content of about 12%. Fabric washing bars have a higher water content, e.g. 20 to 35%. In fabric washing bars ie. bars having a high water content made by the frame cooling process it is known to include high levels of fillers.

The present inventors have now surprisingly discovered that detergent bars having satisfactory properties can be made if the levels of particulate materials are so increased as to form a structurant material, distinct from a mere filler, whose amount can be equal to or even more than the amount of detergent present. A prime advantage is lower cost. The high level of structurant also permits certain useful choices to be made for the detergent content of the bar. The structurant appears to have a surprising combinational effect with the soap, permitting a satisfactory product to be made. For fabric washing bars it is a particular advantage that the bar can be made by plodding (extrusion), and low water levels can be used.

According to one aspect of the present invention, there is provided a detergent bar containing i) 25 to 60% by weight of detergent, of which at least 50% preferably at least 75%, is soap, . Wool

- 3 - S.3009 A r~ ii} 30 to 60% by weight of solid, water-insoluble particulate structurant, which for a framed bar comprises a material other than aluminium silicate when present at a level of not more than 50% by weight in the final bar and iii) 8 to 35% by weight water.

Preferably the bar is made by a method including mechanical working such as plodding.

Herein all percentages are by weight of the bar unless otherwise indicated.

The present invention can provide personal washing bars and fabric washing bars. Preferred water content for both bar types ranges from 8 to 22wt%, more preferred from 8 to 20wtt%. Personal washing bars have a preferred water content of 8 to 15wt%. Fabric washing bars have a preferred water content of 12 to 35wt%, more preferred 12 to 30wt%, even more preferred 15 to 22wt% or even to 20wt%. Other optional ingredients can be included as desired eg. 1 to 2% by weight, perfume, colour and preservative. Fabric washing bars can also contain water soluble alkaline silicate eg. from 10 to 15wt%.

Preferably the detergent content is 30 to 55wt$% more preferably 30 to 45wt%. Preferably the structurant content is 35 to 55wt%, more preferably 40 to 55wt%.

The structurant is insoluble in water, is preferably inert and is preferably selected from (a) silica, sheet or framework crystalline silicate, with or without ion exchange capacity, such as for example, clay, talc, zeolite, kaolin; (b) alkaline earth carbonates such as | dolomite and calcite, magnesite, etc. and (c) water insoluble polysaccharides such as starch or cellulose and

- 4 - 9 60 r (d) mirvtures of any of these. Among suitable starches are those derived from maize, tapioca, rice, wheat and potato.

Freferably the structurant includes at least some atarch, suitably at a level of at least 28wt% with respect to the total amount of structurant present.

Most beneficial results have been obtained when the atructurant material used has average particle size in the range of 0.2 to 30 um, though slight deviation of the particle size is tolerated.

The sap content of the present bar may have large proportions of saturated fatty acide (atearic, palmitic). Because of the presence of the large amount of structurant in the present soap bar, it has surprisingly been found that significant quantities of the soap may be soaps of unsaturated fatty acids, without adversely affecting the properties of the bar. Indeed properties, e.q. lather, may be improved in this way. Fats containing high amounts of unsaturated fatty acid residues are usually oils. The use of soaps from ‘soft’ (high unsaturated) oils avoids or reduces the need to hydrogenate such oils to make soaps from them. High unsaturated fats or oils are generally rich in oleic and linoleic esters. The structurants, particularly starch, can appear to have a combinative or synergistic effect with the soaps from unsaturated fatty acids, which unusually enables the inclusion of large quantities of such soaps in a soap bar. Normal soaps have a fat charge having about 42% unsaturated fatty acid content. We have been able to prepare soaps with a fat charge having up to 75% unsaturated fatty acids.

Thus in the present invention, particularly where the detergent is entirely soap preferably at least 45% of the fatty acid content of the soap is unsaturated fatty acide, preferably 50 to 60%.

Such soaps as are described above can be readily used in preparing the present detergent bars by methods of extrusion using a plodder. 1t is sufficient if the soap

- 5 - . S$.3009 A 260K9 based charge and structurant with or without other additives are subjected to plodding/extrusion as necessary or convenient.

The detergent used may be entirely soap (water-soluble salts preferably sodium salts of Cg=Cyp mono-carboxylic acids). Alternatively the detergent may be primarily soap eg. up to 99wt® of the detergent may be soap with a lesser amount of non-soap detergent,

J10 preferably up to 20%, more preferably 2 to 15%, by weight of the bar. A non-soap detergent is known as a co-active.

Preferred as co-actives are anionic and non-ionic detergents, especially anionic detergents. Most preferred as co-active is alpha-olefin sulphonate (AOS), but other useful anionic detergents include sodium acylisethionate of fatty acid such as coconut, sodium lauryl sulphate (SLS), sodium lauryl ether sulphate (SLES), fatty acid ester sulphonates (FAES) and linear alkylbenzenesulphonate (LAS). The use of anionic co-active can substantially improve the lather performance of the soap bar.

We have further discovered that to improve crack resistance and feel of the soap bar it is ideal to include 0.05 to 5%, preferably 0.1 to 1%, of water soluble polymer. The polymer preferably should have an average molecular weight of 2000 to 10°. This polymer can be preferably selected from polyols (such as polyethylene glycol), polyvinylpyrolidone (PVP), polycarboxylate and polysulphonate. Most preferred is polycarboxylate or a mixture of polycarboxylate and polysulphonate. Such polymers can have a particularly beneficial effect in improving the use properties, e.g. mush, feel and lather characteristics, as well as crack resistance, in soap bars of the present invention. A specific class of polymers which can be used is homopolymers of acrylic acid or a salt thereof and copolymers of acrylic acid or a salt

- 6 - $.3009 A 26009 thereof with 1 to 50% of one or more comonomers. OR

The present detergent bar can be superfatted, i.e. contain a small amount of fatty acid, e.g. up to 8% preferably up to 7%, preferably 2 to 5%.

One or more of the several preferred features can be combined as necessary.

The present bar is preferably made by a method including mechanical working such as plodding. The component parts of the bar can be suitably admixed, mechanical worked, extruded to form billets and optionally stamped and packaged. The present bar can thus be made from readily prepared starting materials.

According however to another aspect of the present invention there is provided a method of manufacture of a detergent bar containing i) 25 to 60% by weight of detergent, of which at least 50% preferably 75% is soap, ii) 30 to 55% by weight of solid, water-insoluble particulate structurant, which where the bar is a framed bar comprises a material other aluminium silicate when present at a level of not more than 50% by weight in the final bar, and iii) 8 to 35% by weight water, wherein a charge of fatty acids which are to provide the soap content of the bar is at least partly neutralised by addition of alkali in the presence of said structurant.

The subsequent processing steps can be conventional,

-7 - S.3009 A 960° whether the bar is made by the frame cooling method or by the plodding (extrusion) method. Typically in the plodding method, after neutralisation, other ingredients of the bar are added and the resulting mixture is processed into bars by milling, plodding and/or stamping.

A method including mechanical working such as plodding is preferred.

Preferably the amount of alkali added to the mixture - of fatty acids and structurant is sufficient and no more to neutralize the fatty acids. Preferably also the water content of the alkali is selected so that the water content of the soap and structurant mixture so produced is the final desired water content of the bar, which is preferably in the range 8 to 30%, more preferably in the range 8 to 20wt%. Such a procedure avoids the need for a drying step. For personal washing bars the water content is preferably 8 to 15%, while for fabric washing bars it is preferably 12 to 35%, more preferably 15 to 22%, even more preferably 15 to 20wt%. Additional materials present in the bar may be perfume, colour and preservative, e.g. 1 to 2%. It may also contain water soluble alkali silicate.

No external heating need be employed in the present method. It is particularly preferred to avoid the use of direct steam heating which would alter the water content of the mixture.

In the present method one or more or all or part of the structurant is present at the neutralisation stage and any remainder added subsequently. It is also possible to mix part of the structurant with compatible additives such as perfume, colourant, super fatting agent and polymer to give a modified structurant and to add it after the neutralisation stage. It is alternatively possible partly to neutralise the charge without structurant and then [I

- 8 - - §.3009 A 26058 complete the neutralisation with structurant. Various permutations and combinations as will fall within the scope of the invention are possible. Preferred features of the composition for use in the method are as give above.

The invention will now be exemplified by non-limitative Examples.

In each of Examples 1 to 9, and accompanying

Comparative Examples, detergent bars were manufactured by plodding a formulation of soap base and structurant with or without additives and were subjected to various tests, as indicated, to determine their properties. Most of these tests are internal standard tests of the applicants, designed to provide quantitative comparison between different detergent bars in a standardized manner within each comparison. The tests will be described briefly: (A) % wear : a set of bars is used to wash in a standard manner once daily by each operator and drained after each wash, for five days. After two further v non-washing days, % wear is determined as weight loss. This is a standarized simulation of use. (B) Cracking : again after the simulation procedure of (A), the degree of cracking, on a standard scale; is determined by a trained observer. (C) Lather : after a standard washing procedure, the volume of lather produced is 3s measured. FH is the French hardness of water.

-9 - $.3009 A 26078

Ce ei: (D) Hardness : is measured using a cone penetrometer with standard weight. The depth of penetration into the bar is measured in 1/10 mm units. (E}) Grittiness/: a standard washing procedure in cold

Feel cold water is followed by estimation of grittiness by feel, by a trained observer. (F) Mush by : a bar (or part) is immersed in water immersion water at 20°C for 2 hours, after which the mush is weighed and expressed as grams per 50 cm? of surface area. (G) Accelerated : crack resistance of the tablet was cracking test was assessed by immersing three quarter portion of the tablet in a pool of water for 30 minutes and allowing it to dry for rest of the day (23.5 hours). The cycle of immersion and drying was repeated over 5 cycles.

The cracks on the faces and edges of the tablets were compared. (H) Lather by : the test involves a panel of untrained volunteers who wash their hands with panels the test tablets once during the test. | The hand wash is performed using 24°

FH water in a bowl and volume of lather produced is measured.

It is to be noted that these methods give results which can be compared within a chosen set under examination or comparison and do not provide absolute

- 10 - $.3009 A values across different sets. 2 6 0 5 8

Example 1 and Comparative Example 1

A personal washing detergent bar was prepared by plodding a soap charge and structurant to give a preparation containing 55.5% soap base and 40% structurant (starch) and had properties closely comparable to those of a control bar containing 98% soap base, i.e. a conventional amount of soap.

Comparative

Example 1 Example 1

Soap base "A"% 98.0 55.5

Structurant (Maize starch) % Nil 40

Distilled coconut fatty acids % Nil 2.5

Perfume & other standard ingredients % 2.0 2.0

Total water content § 14.7 12.0

Test results: Co $ Wear 18.6 20.4

Cracking (average) 5.3 3.8 v

Lather (ml) 7.2° FH 215.0 247.0 Vv 24° FH 208.0 204.0 Y

Hardness (Penetration 1/10 mm) 4.7 8.0

Grittiness at 20°C 7.1 7.2

Mush by immersion at 20°C 7.7 6.7

Soap base "A" is based on the fat charge 10% coconut oil, 81% Hardened Rice Bran Oil and 9% Soft Rice Bran 0il.

Moisture content is 15%. Moisture content of maize starch

- 11 - $.3009 A is 10%. 2 Q 0 IO yn QUO (9

Example 2 and Comparative Example 2

Here the effect of using a large proportion of soaps (30%) of a soft (unhardened) oil (rice bran) in a plodded personal washing bar embodying the present invention was investigated. The lathering is improved, compared with the conventional bar.

Comparative

Example 2 Example 2

Soap base % 98.0(A) 55.5 (B)

Distilled coconut fatty acids % Nil 2.5

Structurant (Maize starch) % Nil 40.0 v

Perfume & other standard ingredients % 2.0 2.0

Total water content 14.7 12.3

Test results: $ Wear 30.3 27.6

Cracking Average 1.6 1.7

Last day 3.0 5.3

Lather 5°H 255.0 284.0 © 24°H 212.0 250.0 °

Grittiness 6.2 6.4

Mush by immersion 8.9 8.0

Soap base A: Same as in Comparative Example 1 (unsaturated fatty acid content 41%)

Soap base B: Based on the fat charge 20% coconut oil, S0% hardened rice bran oil and 30% soft rice bran oil.

-12 - . S,3009 A 26058

Moisture content of soap base = 15% (unsaturated fatty acid content 50%). Moisture content of maize starch is 10%.

Example 2A and Comparative Example 2A:

A plodded laundry bar of the formulation below as made and tested.

Comparative

Example Example Example 2A "2A 2B

Soap base % .100.0(C) 39.0(D) 39.0(D)

Structurantt (kaolin) Nil 40.8 Nil (calcite) Nil Nil 40.8 (zeolite having 22% water) Nil Nil’ 4.5

Alkaline silicate (40% solution) % Nil 12.4 12.4

Added water % Nil Nil 2.7

Perfume and other ingredients § Nil 7.8 0.6

Total water content § 35 15.2 © 15.8

Test results:

Lather in soiled system (ml) 60.0 71.0 66.0

A test cloth dipped in 24° FH water and wrung was soiled after spreading in 24° FH water on the cloth, the soiled cloth was rubbed with the laundry bar in identical manner in both instances and the rubbed fabric was squeezed, lather and liquor were collected and lather volume measured.

- 13 - . S.3009 A 26058

Soap Base (C) is based on fat charge 100% hardened rice bran oil. It is available premixed with the alkaline silicate perfume and other ingredients and contain 35% water (unsaturated fatty acid content 42%). Kaolin contains 2% water.

Soap Base (D) is based on fat charge 20% coconut oil and 80% soft rice bran oil. Moisture content of base = 18% (unsaturated fatty acid content 61%). -

Example 3 and Comparative Example 3:

The present example demonstrates improved lathering compared with the conventional control, when a plodded personal washing bar embodying the present invention contains 15.5% anionic non-soap detergent.

Example 4 Example 5

Soap base % 98.0 (E) 32.35(E)

Alpha Olefin Sulphonate % (having 3% H,0) ML 15.5.

Structurant (Maize starch) % Nil 47.0

Perfume & other standard ingredients % 2.0 2.0

Water Nil 3.15

Total water content % 14.7 13.2

Lather in 24°FH water by J untrained panel (ml) 44.0 60.0

Soap Base E is readily available and based on the following fat charge: 10% coconut, 15% hardened/dehydroxylated castor 0il/45% distilled fatty acids ex hardened rice bran oil, 10% mowrah oil, 15% hardened mowrah oil, 5% sal oil. Moisture

- 14 - ; “560 content of soap base = 15%. Moisture content of starch > 8 10%.

Examples 4 and 5

The present example shows the effect of improved crack resistance and feel by including polymer in a personal washing soap bar prepared by plodding the fat charge, structurant, polymer and other additives.

Example 4 Example 5

Soap base % 38.7(a) 38.7(A)

Alpha Olefin Sulphonate % (having 30% H,0) 10.3 10.3

Structurant (Maize starch) % 45.0 45.0

Perfume & other standard ingredients % 2.0 2.0

Distilled coconut fatty acid % 2.5 2.3

Carbopol 1720 % Nil 0.2

Water % 1.5 1.5

Total water content % 12.1 12.1 (Carbopol 1720 (trademark) is a polycarboxylate polymer)

Soap Base A as in Example 1. Maize starch has 10% water.

Results

The formulation (Example 5) containing 0.2% Carbopol 1720 was found to be superior to Example 4 (i.e. without

Carbopol 1720) in feel and crack resistance.

All the soap bases can be of a single source of fat charge. Alternatively the soap base can be obtained from suitable combination of two or more soap bases derived from different fat charges. ’

- 15 - S.3009 A , 2605

Examples 6 to 9 H S

Comparative

Example for Examples 6 to 9 6 1 8 9

Soap base % 95 (F) 27(a) 26 (A) 26 (A) 26 (A)

Alpha Olefin Sulfonate % (having 3% H,0) Nil 14 10.7 12.1 12.1

Structurant §

Maize starch Nil 47 54 34 49

Kaolin Nil 0 0 20 0

Distilled Coconut ~ fatty acids § 3.3 2.5 3 3 3

Distilled Palmitic Nil Nil Nil Nil 5 acid &

Carbopol 1720 % Nil 0.25 0.3 0.3 0.3

Zinc stearate % Nil 1 1 1 1

Perfume and other 2 1.7 1.7 1.7 1.7 standard ’ ingredients %

Total water 13 15.7 13 9.5 11.5 content %

Lather in 24FH 34.3 35.6 43.37 44.8’ 44.5 r water by untrained panel (ml)

- 16 - . 5.3009 A 26058

Soap base (F) is available and is based on the ei fat charge: 20% coconut oil, 62% palm stearin, 18% soft rice bran oil

Mositure content of soap base (F) = 14%

Unsaturated fatty acid content of soap base (F) = 42%

Soap base (A) is based on the fat charge 10% coconut oil, 81% Hardened rice bran oil and 9% soft rice bran oil and is available.

Moisture content of soap base (A) = 15%

Unsaturated fatty acid content of soap base (A) = 41%

The compositions of the bars embodying the present invention in Examples 1 to 9 are summarised in the following Table in terms of total percentage detergent content, the percentage soap content with respect to total detergent content, the percentage content of unsaturated soap with respect to the total soap content, the percentage amount in the bar and type of structurant and the total analysed moisture content of the bar. It should be noted that the following table, as in the claims and elsewhere in the present specification other than in the descriptions given in the Examples, soap content is given as anhydrous soap. In the above description of Examples 1 to 9 it is given as percentage with respect to the bar of hydrated soap ingredient. In the following table P/W means personal washing bar and F/W means fabric washing bar.

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- 18 ~ $.3009 a

Example 10: 2 6 0 o 8

A fatty acid mixture was prepared using the following materials: i. coconut fatty acid 20% by wt. ii, hardened rice bran fatty acid 50% by wt. iii. soft rice bran fatty acid 30% by wt.

It was thoroughly mixed and warmed to homogenise the same. 2500 gms of the above charge was taken in a mixer and 2400 gm of a structurant made of starch (maize starch) was added with stirring. When thoroughly stirred, the mixture was subjected to neutralisation by gradual addition of a stoichiometric amount of 48.7% aqueous sodium hydroxide solution under stirring. The amount of the aqueous solution was 780 gms. The temperature of neutralisation reaction rises and the reaction mixture is cooled indirectly to a temperature not exceeding 40-45°C.

Stirring is continued and the following additions were made: a) Distilled coconut fatty acid 150 gms. b) Perfume and other standard ingredients 105 gms.

The final mixture is not powdery and is doughy enough for further processing. The mass is further blended for = 10 minutes and then noodled, milled twice and plodded in two stage vacuum plodder. The plodded material is cut into billets of standard size and stamped. The moisture content of the bar produced is 12.3%.

A similar product was prepared without structurant.

It had a total fatty matter of about 78% before noodling whereas the product prepared according to the presently described process had a total fatty matter of about 44%

. } 2? I~ a 26058 only before noodling and still fared equally well with the conventional processing equipment of noodler, mills and plodder.

The two products obtained had comparable properties.

Additional examples of bars prepared by the method embodying the present invention and incorporating the optional features described above yielded satisfactory results with various combinations of features and alternatives.

Examples 11. 12 & 13

Examples

Ay AAS

Soap base¥ wt 54 54 56

Structurant: kaolin wt’ 4.) 20 O starch wt 0 20 40

Ferfume and other ingredients 2 2 2

Wear (g loss per tablet) HE. 8 TEs. nEL.9

Mush hy immersion (gm/B0em™ ) 1 9.6 9.4

Wt. loss on mashing 10 77 83.4

Jy gm/ 50cm”

Brit 7.3 7.9 7.0 x -

Density g/cm’ 1.38 1.25 1.15

XBoap hase was a fat charge of 20wt% cocoanut oil and 80wt’%4 soft

Rice Bran 0il.

\ 26058 —- 20 - - ~ ,

Molsture content of the base was 13wt4 and its unsaurated fatty acid content was 60.%5wt%.

Although we do not wish to be bound by theory, we believe that the improved mush properties in Example 12 and the improved mush and wear characteristics in Example 13% are due to the relative size difference of particulate starch and its density compared to kaolin. The particle density of the starch was 1.9 g/cm and of the kaolin was 2.5 am/cm The average particle size of the starch was 8 to 30 microns and of the kaolin was 0.2 to 2.0 microns.

Claims (24)

‘ =28= es CLAIMS: /

1. A detergent bar containing (i) 25 to 40% by weight of detergent selected from the group consisting of soap I of Ca to Coo monocarboxylic fatty acids and mixtures thereof with non-socap anionic or nonionic detergent in which mixtures the weight of soap exceeds the weight of non- soap detergents : (ii) 30 to 60%Z by weight of solid, water- insoluble particulate structurant selected from the group consisting of sheet or framework crystalline silicate, alkaline earth carbonate, } water-insoluble polysaccharide and mixtures thereof, with the proviso that in a framed bar : with 30 to 50% by weight of structurant, the structurant is not solely aluminium silicates; (iii) 8 to 357 by weight water.

2. A detergent bar according to claim 1 or claim 2 containing 8 to 15% by weight of water.

3. A detergent bar according to claim 1 containing 12 to 35% by weight of water. !

=29=

:

4. A detergent bar according to claim 3 containing 195 to 22% by weight of water. i:

5. A detergent bar according to claim 1 containing said detergent in an amount from 30 to 45% by weight.

&. 6 detergent bar according to claim 1 containing said structurant in an amount from 40 to 55% by weight.

7. a detergent bar according to claim 1 wherein said structurant is selected from the group consisting of clay, talc, zeolite, kaolin and starch.

a. A detergent bar according to claim 1 wherein said structurant has an average particle size in the range 0.2 to 30 um.

9. A detergent bar according to claim 1 wherein at least 45% by weight of the fatty acid content of the 'spap is unsaturated fatty acids.

10. A detergent bar according to claim 9 wherein 50 to 50% by weight of the fatty acid content of the spap is unsaturated fatty acids.

f - =aI30= ’ 11. A detergent bar according to claim 1 wherein i oo said detergent includes an amount of said nbn-soap . anionic or nonionic detergent not exceeding 20% hy B weight of the bar. } :

12. A detergent bar according to claim { including 0.05 to 5% by weight of water soluble polymer.

13. A detergent bar accordihg tb claim {2 wherein : the polymer has an average molecular weight in the range 2000 to 10%.

14. A detergent bar according to claim 12 wherein the polymer is a polycarboxylate or a mixture of . * 1 polycarboxylate and polysuiphonate.

15. A detergent bar according to claim 4 7. including an amount, not exceeding 7% by weight; of fatty acid. . Co

16. A method of manufacture of a detergent bar oo containing oo (1) 25 to 60% by weight of detergent selected from the group consisting thereof of Cq to Coo : monocarboxylic fatty acids and mixtures of soap with non—-soap anionic or nonionic detergent in which mixtures the weight of soap exceeds the weight bf : : Ce hy % wie 1h va. +

=31= non—soap detergents; (ii) 30 to 60% by weight of solid, water—insoluble particulate structurant selected from the group consisting of sheet or framework crystalline silicate, alkaline earth carbonate, water-insoluble polysaccharide and mixtures thereof, with the proviso that in a framed bar with 30 to 50% by weight of structurant, the structurant is not solely aluminium silicate; (iii) 8 to 35% by weight water, wherein an amount of said fatty acids which are to provide the soap content of the bar is at least partly neutralised by addition of alkali in the presence of said structurant. 13 17. A method according to claim 1&6 which includes a subsequent step of mechanically working the resulting mixture.

18. A method according to claim 16 wherein the amount of alkali added to the mixture of fatty acids structurant is sufficient to neutralize the fatty acids.

19. A method according to claim 16 wherein the water content of the alkali is selected so that the

=X2= water content of the mixture so produced is the final desired water content of the bar. '

20. A method according to claim 16 wherein the detergent content of the bar is 30 to 45% by weight.

21. A method according to claim 16 wherein the structurant content of the bar is 40 to 55% by weight.

22. A method according to claim 16 wherein the structurant is selected from the group consisting of clay, talc, zeolite, kaolin and starch.

23. A method according to claim 16 wherein part of the structurant content is added after neutralisation.

24. A method according to claim 16 wherein. the fatty acid charge is partially neutralised without structurant and then at least some of the structurant is added. . ' SUNIL MANOHARIAL SAHNI DEVADATTA SHIVAJI SANI+ SANKHOLKAR } Inventors i : oo