DETERGENT COMPOSITION

The present invention relates to extrudable detergent compositions, in particular to detergent compositions in bar form and comprising benefit agents, which bars have improved resistance to wet-cracking and embrittlement .

Detergent compositions are used by people all over the world, for care and cleansing of the skin. It is known that detergents help in removing dirt from the skin, the mechanism of which is well understood. In addition to using detergents for their primary function i.e. cleansing, they are also useful as delivery vehicles for various benefit agents e.g. moisturizing agents and skin-lightening additives, which are incorporated therein for added benefits to the user. Consumer research has revealed that presence of such added benefit agents in detergent compositions lends considerable consumer appeal. Consumers are also interested in milder ways to cleanse their skin which results in less damage to the skin's natural protective barrier and also, which retains the moisture in their skin. It can be appreciated that this consumer appeal is directly proportional to the number of different benefits afforded by the detergent composition, during use and post-use. Therefore, detergent compositions capable of providing multiple benefits are highly desirable.

Skin-lightening and moisturisation remain the most preferred benefits among others, which the consumers seek from personal care compositions. Skin lightening is especially desired by people in the Asian subcontinent, while

moisturisation is desired by people across the world. Various skin lightening actives have been used and reported in literature that include herbal extracts and synthetic chemicals. Dicarboxylic acids, such as azelaic acid and their salts form one class of potent skin-lightening agents, which are reported in prior art. The use of dicarboxylic acids has also been reported in GB 2068997 (Colgate, 1981) for prevention/reduction of wet-cracking in detergent bars.

On the other hand, the benefits of alpha-hydroxy acids are also well known, which include skin-lightening, moisturisation and chemical exfoliation. Moisturisation benefit is generally achieved by incorporation of high levels of alpha-hydroxy acids. This has been described in GB 1417183 (Unilever, 1975), which claims specific moisturisation benefits without adversely affecting the processing of bars. It is to be noted that in this publication, the levels of alpha-hydroxy acid is from 20-55 wt%, preferably at least 20 wt% of the composition. GB 1460442 (Unilever, 1977) describes detergent bars for use in personal washing, which contain soap, synthetic detergents and skin moisturizing compound selected from dicarboxylic acids, hydroxy acids, amino acids or combinations thereof. The level of incorporation is from 5 - 55 wt%. These bars give moisturisation benefits owing to the high levels of the acids.

The present inventors wanted to combine the skin lightening benefits of dicarboxylic acids with the benefits of alpha- hydroxy acids and offer the same through a wash-off detergent composition.

When the present inventors tried to make detergent compositions comprising the above two classes of benefit agents, they found, surprisingly that when the composition was extruded in the form of bars, the bars exhibited wet- cracking. This was unexpected as dicarboxylic acids were added to detergent bars in the past to make them crack- resistant .

By way of extensive experimentation, the present inventors found that the same problem could be effectively solved by incorporating reduced quantity of surfactants in the detergent composition.

It is therefore, an object of the present invention to provide multiple benefit agents through a detergent composition .

Another object of the present invention is to make crack- resistant extrudable detergent compositions, having good ion-use properties, comprising combination of dicarboxylic acid and alpha-hydroxy acid.

According to an aspect, the present invention relates to an extrudable detergent composition comprising, 20 % to 80 % by weight soap; 0.5 % to 5 % by weight surfactant selected from anionic, non-ionic, amphoteric and zwitter-ionic surfactants; 0.1 % to 10 % by weight water soluble salt of dicarboxylic acid having the formula COOH-(CH ₂ ) n~COOH where "n" is an integer from 2 to 8; 0.1% to 10 % by weight water soluble salt of alpha-hydroxy acid.

According to a preferred aspect, the surfactant includes a mixture of anionic surfactant and non-ionic surfactant, more preferably the anionic surfactant is present from 2 % to 4 % and the non-ionic surfactant is present upto 1 % by weight.

According to a highly preferred aspect, the anionic surfactant is an alkali metal salt of C8-C18 primary alcohol sulphate and the non-ionic surfactant is an amine oxide. The term "extrudable" for the purpose of this invention means that the composition is capable of being extruded through dies of required dimensions, in the form of streams, which can be cut into small-sized billets or bars, which are ready for use.

The term "detergent composition" has been used herein, synonymously with soaps, soap bars and personal washing bars .

Other advantages of the invention will hereinafter become more fully apparent from the detailed description of the preferred embodiments of the invention.

The present invention relates to extrudable detergent compositions comprising benefit agents.

The wet cracking of soap, i.e., the tendency of soap to form cracks when moistened and dried, particularly during use, has been a general problem. Wet cracking refers to known defect of soap bars in developing cracks when repeatedly moistened and dried. Detergent bars that exhibit wet- cracking are not preferred by the user. The present

inventors have provided a detergent composition that provides skin-lightening and moisturisation benefits to the user, without compromising on the quality of the physical bar structure and integrity, while in use.

In the detergent compositions of the present invention, It is preferred that the soap content is from 20 to 80 % by weight, more preferably from 40-75%.

The predominant wash-active agent in the detergent composition of the present invention could be any conventional soap, otherwise referred to as fatty acid salt. The soap may be derived from one or a mixture of C8-C22, preferably C12-C18 straight or branched chain, saturated or unsaturated monocarboxylic acids, of natural or synthetic origin. Natural sources, e. g. animal, marine or vegetable fats and oils, almost always yield mixtures of these fatty acids, all of which may be employed. Examples thereof include the fatty acids derived from coconut oil, olive oil, palm kernel oil, tall oil, soy bean oil, cottonseed oil, peanut oil, safflower oil, sunflower seed oil, corn oil, fish oils, tallow, and the like. Illustratively, individual fatty acids include capric, lauric, myristic, stearic, oleic, palmitic, palmitoleic, ricinoleic, linoleic, and linoleric acid and the like. The fatty acids may also be derived synthetically by paraffin oxidation, Oxo-synthesis, or the like. The cation or salt portion of the soap is preferably an alkali metal such as potassium and, especially, sodium, but may alternatively be an alkaline earth metal such as calcium or magnesium, or ammonium,

substituted ammonium, or organic amine such as a lower alkylamine or a lower alkanolamine .

Tallow fatty acids can be derived from various animal sources and generally comprise about 1-8% myristic acid, about 21-32 % palmitic acid, about 14-31% stearic acid, about 0-4% palmitoleic acid, about 36-50% oleic acid and about 0-5% linoleic acid. A typical distribution is 2.5 % myristic acid, 29% palmitic acid, 23% stearic acid, 2% palmitoleic acid, 41.5% oleic acid, and 3 % linoleic acid. Other similar mixtures, such as those from palm oil and those derived from various animal tallow and lard are also included. Coconut oil refers to fatty acid mixtures having an approximate carbon chain length distribution of 8% C8, 7% ClO, 48% C12,17 % C14, 8% C16, 2% C18, 7% oleic and 2% linoleic acids (the first six fatty acids listed being) . Coconut oil employed for the soap may be substituted in whole or in part by other "high-lauric" oils, that is, oils or fats wherein at least 50% of the total fatty acids are composed of lauric or myristic acids and mixtures thereof. These oils are generally exemplified by the tropical nut oils of the coconut oil class. For instance, they include: palm kernel oil, babassu oil, ouricuri oil, tucum oil, cohune nut oil, murumuru oil, jaboty kernel oil, khakan kernel oil, dika nut oil, and ucuhuba butter.

A preferred soap is a mixture of about 30% to about 40% coconut oil and about 60% to about 70% tallow. Mixtures may also contain higher amounts of tallow, for example, 15% to 20% coconut and 80 to 85% tallow. The soaps may contain

unsaturation in accordance with commercially acceptable standards. Excessive unsaturation is normally avoided. Without wishing to be bound by theory, the presence of strong electrolytes, into the soap bar, however, can create processing problems as they disrupt the liquid crystal phases of the soap matrix which binds the insoluble soaps together. Without these liquid crystal phases, soap cannot be extruded in any meaningful way. Therefore, it is preferred that the content of added inorganic electrolytes in the detergent composition is kept very low and preferably less than 1% by weight of the composition. The electrolytes include Sodium chloride, Sodium sulphate, Sodium Sulphite and Sodium bisulphate, which are generally added to detergent compositions.

It is preferred that the composition comprises from 0.1% to 10 %, more preferably 1% to 5% and most preferably 1% to 2% by weight water soluble salt of dicarboxylic acid having the formula COOH-(CH 2) n-COOH where "n" is an integer from 2 to 8. More preferably, the dicarboxylic acid is selected from adipic acid, azelaic acid or sebacic acid, more preferably sebacic acid. The water soluble salts include alkali metal salts, e.g. sodium or potassium, or alkanolamine or ammonium salts. Dicarboxylic acids are used herein, primarily as skin-lightening benefit agents.

The water soluble salt of alpha-hydroxy acid is preferably present from 0.1% to 10 %, more preferably from 1% to 5% and most preferably from 1% to 2% by weight of the composition. Preferably, the alpha-hydroxy acid is selected from glycolic acid, lactic acid, malic acid, citric acid or tartaric acid

or mixtures thereof. Lactic acid is the most preferred. The water soluble salts include alkali metal salts, e.g. Sodium or potassium, or alkanolamine or ammonium salts.

Alpha-hydroxy acids (AHAs) are naturally occurring organic carboxylic acids such as glycolic acid, a natural constituent of sugar cane juice and lactic acid, found in sour milk and tomato juice. Topical formulations incorporating these acids are frequently used and they are also present in a wide range of heavily promoted cosmetic products. Among its' various reported benefits exfoliation of dead skin cell, moisturization of the skin, reversal of photodamage and reduction in wrinkles, brown spots and roughness. The overall result is skin which looks and feels better.

In accordance with the present invention, the detergent composition comprises 0.5 % to 5 %, more preferably from 0.5 % to 2% by weight surfactant selected from anionic, non- ionic, amphoteric, betaines or zwitter-ionic surfactants. Cationic surfactants are not generally suited for the present invention, as they are not compatible with the predominantly anionic atmosphere of the composition, due to the relatively large proportion of fatty acid soaps. It is however stated that traces of cationic surfactants, when present in the composition as impurity, or when otherwise added, does not cause any notable undesirable effect.

The synthetic detergents contemplated, as surfactants under this invention are compounds other than soap whose detersive

properties, like soap, are due to the presence of a hydrophilic and a hydrophobic group in the molecule.

The contemplated water soluble anionic surfactants are the alkali metal (such as sodium and potassium) salts of the higher linear alkyl benzene sulfonates and the alkali metal salts of sulfated ethoxylated and unethoxylated fatty alcohols, and ethoxylated alkyl phenols.

Preferred sulfated surfactants which can be used in the compositions of the present invention include sulfated ethoxylated and unethoxylated fatty alcohols, preferably linear primary or secondary monohydric alcohols with Cs -Cis, preferably C12 -C16, alkyl groups and, if ethoxylated, on average about 1-15, preferably 3-12 moles of ethylene oxide (EO) per mole of alcohol, and sulfated ethoxylated alkylphenols with Cs -C16 alkyl groups, preferably Cs -Cg alkyl groups, and on average from 4-12 moles of EO per mole of alkyl phenol.

The preferred class of sulfated ethoxylated surfactants are the sulfated ethoxylated linear alcohols, such as the Cs -Cis alcohols ethoxylated with an average of from about 1 to about 12 moles of ethylene oxide. A most preferred sulfated ethoxylated detergent is made by sulfating a C12 -Ci ₅ alcohol ethoxylated with 3 moles of ethylene oxide.

The anionic surfactant could be, for example, an aliphatic sulfonate, such as a primary alkane (e.g., C 8 -C 22 ) sulfonate, primary alkane (e. g., C 8 -C 22 ) disulfonate, C 8 -C 22 alkene sulfonate, C 8 -C 22 hydroxyalkane sulfonate

or alkyl glyceryl ether sulfonate (AGS) ; or an aromatic sulfonate such as alkyl benzene sulfonate. The anionic may also be an alkyl sulfate (e.g., C 12 -C 18 alkyl sulfate) or alkyl ether sulfate (including alkyl glyceryl ether sulfates) . Among the alkyl ether sulfates are those having the formula:

RO(CH2CH2O)nSO3M

wherein R is an alkyl or alkenyl having 8 to 18 carbons, preferably 12 to 18 carbons, n has an average value of greater than 1.0, preferably between 2 and 3; and M is a solubilizing cation such as sodium, potassium, ammonium or substituted ammonium. Ammonium and sodium lauryl ether sulfates are preferred.

The anionic surfactant may also be alkyl sulfosuccinates

(including mono- and dialkyl, e.g., C 6 -C 22 sulfosuccinates) ; alkyl and acyl taurates, alkyl and acyl sarcosinates, sulfoacetates, C 8 -C 22 alkyl phosphates and phosphates, alkyl phosphate esters and alkoxyl alkyl phosphate esters, acyl lactates, C 8 - C 22 monoalkyl succinates and maleates, sulphoacetates, and acyl isethionates .

Taurates are generally identified by formula; R ² CONR ³ CH2CH2SO3 M wherein R ² ranges from C8 -C20 alkyl, R ³ ranges from Cl -C4 alkyl and M is a solubilizing cation. Acyl isethionates are prepared by reaction between alkali metal isethionate with mixed aliphatic fatty acids having from 6 to 18 carbon atoms and an iodine value of less than

20. At least 75% of the mixed fatty acids have from 12 to 18 carbon atoms and up to 25% have from 6 to 10 carbon atoms. Among the anionic surfactants, C8-C28 primary alcohol sulphates are most preferred.

Preferred amine oxides inlcude dimethyldodecylamine oxide, oleyldi (2-hydroxyethyl) amine oxide, dimethyloctylamine oxide, dimethyldecylamine oxide, dimethyltetradecylamine oxide, di (2-hydroxyethyl) tetradecylamine oxide, 3- didodecoxy-2- hydroxypropyldi (3-hydroxypropyl) amine oxide, and dimethylhexadecylamine oxide, more preferably C12-14 alkyldimethyl amine oxide, such as hexadecyl dimethylamine oxide, octadecylamine oxide, lauryl dimethyl amine oxide and their hydrates. The N-oxide group is a weak base having a pKb of about 9. Amine oxides suitable for use herein are made commercially by a number of suppliers, including Akzo Chemie and Ethyl Corp. More preferred amine oxides are selected from C12-14 alkyldimethyl amine oxide, such as hexadecyl dimethylamine oxide, octadecylamine oxide, lauryl dimethyl amine oxide and their hydrates, most preferably lauryl dimethyl amine oxide.

Zwitterionic surfactants are exemplified by those which can be broadly described as derivatives of aliphatic quaternary ammonium, phosphonium, and sulfonium compounds, in which the aliphatic radicals can be straight or branched chain, and wherein one of the aliphatic substituents contains from about 8 to about 18 carbon atoms and one contains an anionic group, e.g., carboxy, sulfonate, sulfate, phosphate, or phosphonate.

Examples of such preferred surfactants include: 4-[N,N-di(2- hydroxyethyl) -N-octadecylammonio] -butane-1-carboxylate; 5- [S-3-hydroxypropyl-S-hexadecylsulfonio] -3-hydroxypentane-l- sulfate; 3- [P, P-diethyl-P-3, 6, 9- trioxatetradexocylphosphonio] -2-hydroxypropane- 1-phosphate; 3- [N, N-dipropyl-N-3-dodecoxy-2-hydroxypropylammonio] - propane-1- phosphonate; 3- (N, N-dimethyl-N- hexadecylammonio) propane-1-sulfonate; 3- (N, N-dimethyl-N- hexadecylammonio) -2-hydroxypropane-l-sulfonate; 4- [N,N-di (2- hydroxyethyl) -N- (2-hydroxydodecyl) ammonio] -butane-1- carboxylate; 3- [S-ethyl-S- (3-dodecoxy-2- hydroxypropyl) sulfonio] -propane-1- phosphate; 3- [P, P- dimethyl-P-dodecylphosphonio] -propane-1-phosphonate; and 5- [N,N-di (3-hydroxypropyl) -N-hexadecylammonio] -2-hydroxy- pentane-1- sulfate.

Amphoteric detergents which may be used in this invention include at least one acid group. This may be a carboxylic or a sulphonic acid group. They include quaternary nitrogen and therefore are quaternary amido acids. They should generally include an alkyl or alkenyl group of 7 to 18 carbon atoms. Suitable amphoteric surfactants include amido betaines and sulphobetaines .

Preferred examples of the sulfobetaine includes alkylaminopropyl sulfobetaines, alkylhydroxy sulfobetaines, amide hydroxy sulfobetaines, and amide propyl sulfobetaines, of which lauryl dimethyl hydroxy sulfobetaine, myristyl dimethyl hydroxy sulfobetaine, N,N-dimethyl lauramide propyl-2-hydroxy sulfobetaine, and N,N-dimethyl cocamide propyl-2-hydroxy sulfobetaine are particularly preferred.

Among these, lauryl dimethyl hydroxy sulfobetaine and myristyl dimethyl hydroxy sulfobetaine are most preferred. Preferred examples of the amido betaines include lauramide propyl betaine and cocamide propyl betaine.

The nonionic which may be used includes in particular the reaction products of compounds having a hydrophobic group and a reactive hydrogen atom, for example aliphatic alcohols, acids, amides or alkyl phenols with alkylene oxides, especially ethylene oxide either alone or with propylene oxide. Specific nonionic detergent compounds are alkyl (C6 -C22 ) phenols-ethylene oxide condensates, the condensation products of aliphatic (C8 -C18 ) primary or secondary linear or branched alcohols with ethylene oxide, and products made by condensation of ethylene oxide with the reaction products of propylene oxide and ethylenediamine . Other so-called nonionic detergent compounds include long chain tertiary amine oxides, long chain tertiary phosphine oxides and dialkyl sulphoxides. The nonionic may also be a sugar amide, such as a polysaccharide amide. Preferred alkyl polysaccharides are alkylpolyglycosides of the formula;

R ² O(CnH2nO) t (glycosyl) x,

wherein R ² is selected from the group consisting of alkyl, alkylphenyl, hydroxyalkyl, hydroxyalkylphenyl, and mixtures thereof in which alkyl groups contain from about 10 to about 18, preferably from about 12 to about 14, carbon atoms; n is 0 to 3, preferably 2; t is from 0 to about 10, preferably 0; and x is from 1.3 to about 10, preferably from 1.3 to about

2.7. The glycosyl is preferably derived from glucose. To prepare these compounds, the alcohol or alkylpolyethoxy alcohol is formed first and then reacted with glucose, or a source of glucose, to form the glucoside (attachment at the 1- position) . The additional glycosyl units can then be attached between their 1- position and the preceding glycosyl units 2-, 3-, 4- and/or 6-position, preferably predominantly the 2-position.

Preferred nonionic surfactants for use in the compositions of the present invention include ethoxylated fatty alcohols, preferably linear primary or secondary monohydric alcohols with C 10 -Ci8, preferably C12 -C16, alkyl groups and on average about 1-15, preferably 3-12 moles of ethylene oxide (EO) per mole of alcohol, and ethoxylated alkylphenols with Cs -C16 alkyl groups, preferably Cs -Cg alkyl groups, and on average about 4- 12 moles of EO per mole of alkyl phenol. The preferred class of nonionic surfactants compounds are the ethoxylated linear alcohols, such as the C12 -C16 alcohols ethoxylated with an average of from about 1 to about 12 moles of ethylene oxide. A most preferred nonionic detergent is a C12 -Ci5 alcohol ethoxylated with 3 moles of ethylene oxide .

The nonionic surfactant should be liquifiable, e.g. at elevated temperatures up to about 900C, to facilitate processing of the soap composition into bar form. Other nonionic compounds which are suitable are the polyoxyalkylene esters of the organic acids 4 such as the higher fatty acids, the resin acids, tall oil acids, or acids from petroleum oxidation products. These esters will

usually contain from about 10 to about 22 carbon atoms in the acid moiety and from about 12 to about 30 moles of ethylene oxide or its equivalent.

Still other nonionic surfactants are the alkylene oxide condensates with the higher fatty acid amides. The fatty acid group will generally contain from about 8 to about 22 carbon atoms, and this will be condensed with about 10 to about 50 moles of ethylene oxide. The corresponding carboxamides and sulphonamides may also be used as substantial equivalents.

The oxyalkylate higher aliphatic alcohols are the preferred nonionic surfactants for compositions according to the present invention, The fatty alcohols should contain at least 6 carbon atoms, and preferably at least about 8 carbon atoms. The most preferred alcohols are lauryl, myristyl, cetyl, stearyl, and oley] alcohols, and the said alcohols should be condensed with at least about 6 moles of ethylene oxide. A typical nonionic product is C12-C13 aliphatic alcohol condensed with about 6.5 moles of ethylene oxide. The corresponding alkyl mercaptans when condensed with ethylene oxide are also suitable in the compositions of the present invention.

As exemplary of specific nonionic surfactants, mention is made of dinonyi phenol + 15 E. O. (1 mole of dinonyl phenol reacted with 15 moles of ethylene oxide) , dodecyi mercaptan + 10 E.O., lauramide +8 E. O. , stearic acid +20 E.O., tetradecyl amine + 14 E.O., dodecyi sulphonamide +6 E. 0., and myristyl alcohol -1- 10 E. O. Preferred are condensation

products of one mole of an alkanol, preferably straight chain and primary, of about 9 to 20, especially 10 to 18, carbon atoms with about 4 to 20, especially 5 to 15, moles of ethylene oxide, as represented for example by Neodol 23- 65 (C12- 13 alkanol + 6.5 E.O.) and Neodol 45-13 (C4-15 alkanol + 13 E.O. ) .

Mixtures of the foregoing synthetic detergent type of surfactants, e.g., of anionic and nonionic, or of different specific anionic or nonionic surfactants, may be used to modify the detergency, lather characteristics, and other properties of the composition. As indicated in the examples below, inclusion of these surfactants in the extrudable detergent compositions of the present invention enables the attainment better resistance to wet cracking and also provides desired lather profile to the composition.

Specific advantages have been observed when the extrudable detergent composition when the surfactant It is preferred that the surfactant includes a mixture of anionic and nonionic surfactants, especially a mixture of an anionic surfactant, preferably an alkali metal salt of C8-C18 primary alcohol sulphate and an amine oxide.

In addition to the above essential ingredients, the detergent composition of the present invention could also comprise any or all of the following ingredients used to increase its shelf life, aesthetics or functionality namely; Vitamins such as vitamin A and E, and vitamin alkyl esters such as vitamin C alkyl esters; lipids such as cholesterol, cholesterol esters, lanolin, ceramides, sucrose esters, and

pseudo-ceramides; liposome forming materials such as phospholipids, and suitable smphiphilic molecules having two long hydrocarbon chains; essential fatty acids, poly unsaturated fatty acids, and sources of these materials; triglycerides of unsaturated fatty acids such as sunflower oil, primrose oil, avocado oil, almond oil; vegetable butters formed from mixtures of saturated and unsaturated fatty acids such as Shea butter; mineral such as sources of zinc, magnesium, and iron; skin conditioners such as silicone oils, gums and modifications thereof such as linear and cyclic polydimethylsiloxanes, amino, alkyl, and alkylaryl silicone oils; hydrocarbons such as liquid paraffins, petrolatum, vasaline, microcrystalline wax, ceresin, squalene, pristan, paraffin wax and mineral oil; conditioning proteins such as milk proteins, silk proteins and glutins; cationic polymers as conditioners which may be used include Quatrisoft LM-200 Polyquaternium-24, Merquat Plus 3330--Polyquatermium 39; and Jaguar® type conditioners, humectants such as glycerol, sorbitol, and urea emmolients such as esters of long chain fatty acids, such as isopropyl palmitate and cetyl lactate;

In addition to the above, the composition may also include a deep cleansing agent. These are defined here as ingredients that can either increase the send of refreshment immediately after cleansing or can provide a sustained effect on skin problems that are associated with incomplete cleansing. Deep cleansing agents include: antimicrobials such as 2-hydroxy-4, 2 ' , 4 ' - trichlorodiphenylether (DP300), 2, 6-dimethyl-4- hydroxychlorobenzene (PCMX), 3,4,4'- trichlorocarbanilide

- I i

(TCC), 3-trifluoromethyl-4, 4 ' -dichlorocarbanilide (TFC), benzoyl peroxide, zinc salts, tea tree oil. Further optional agents include anti-acne agents, such as salicylic acid, lactic acid, glycolic acid, and citric acid, and benzoyl peroxide (also an antimicrobial agent) ; oil control agents including sebum suppressants, mattifiers such as silica, titanium dioxide, oil absorbers, such as microsponges ; astringents including tannins, zinc and aluminum sales, plant extracts such as from green tea and Witchhazel (Hammailes) ; scrub and exfolliating particles, such as polyethylene spheres, agglomerated silica, sugar, ground pits, seeds, and husks such as from walnuts, peach, avocado, and oats, salts; cooling agents such as menthol and its various derivatives and lower alcohols; fruit and herbal extracts; skin calming agents such as aloe vera; essential oils such as mentha, jasmine, camphor, white cedar, bitter orange peel, ryu, turpentine, cinnamon, bergamot, citrus unshiu, calamus, pine, lavender, bay, clove, hiba, eucalyptus, lemon, starflower, thyme, peppermint, rose, sage, menthol, cineole, eugenol, citral, citronelle, borneol, linalool, geranoil, evening primrose, camphor, thymol, spirantol, penene, limonene and terpenoid oils; Sun-screens such as 4-tertiary butyl-4 ' -methoxy dibenzoylmethane (available under the trade name PARSOL 1789 from Givaudan) and/or 2-ethyl hexyl methoxy cinnamate

(available under the trade name PARSOL MCX from Givaudan) or other UV-A and UV-B sun-screens may also be incorporated.

Other benefit agents that can be employed include antiageing compounds and skin lightening agents, antioxidants such as, for example, butylated hydroxytoluene (BHT) may be used

advantageously in amounts of about 0.01% or higher if appropriate .

Another ingredient which may be included are physical exfoliants such as polyoxyethylene beads, walnut shells and apricot seeds. Incorporation of such physical exfoliants give added benefits, over and above the chemical exfoliation provided by alpha-hydroxy acids. Such added benefits are highly desired by the consumers. The particle size of the exfoliants preferably lies between 50 microns to 1000 microns, more preferably 100 microns to 500 microns and most preferably 100 to 200 microns.

A final group of optional ingredients is optical modifiers which are defined as materials that modify the optical texture or introduce a pattern to increase the distinctiveness of the bar. Examples of suitable optical modifiers include: speckles/bits such as ground fruit pits, seeds, polyethylene beads, mineral agglomerates, and loofha; reflective plate- like particles such as mica; pearlizing agents such as coated micas, and certain waxes; wax/plastic slivers that resemble for example fruits slices; Vegetable or fruit slivers g) mattefiers such as TiO2 and mixtures of the above Further, the bar composition of the invention may include 0 to 25 % by weight of crystalline or amorphous aluminium hydroxide. The said aluminium hydroxide can be generated in- situ by reacting fatty acids and/or non-fatty mono- or polycarboxylic acids with sodium aluminate, or can be prepared separately by reacting fatty acids and/or non-fatty mono- or polycarboxylic acids with sodium aluminate and

adding the reaction product to the soap. Another class of hardening agents are insoluble inorganic or mineral solids that can structure the discontinuous phase by network formation or space- filling. These include fumed, precipitated or modified silica, alumina, calcium carbonate, kaolin, and talc. Alumino-silicate clays especially synthetic or natural hectorites can also be used. In addition to the benefit agents, suitable bar structurants that provide integrity to the bar could also be used. Water insoluble structurants also have a melting point in the range 40-100 °C, more preferably at least 50 °C, notably 50 ⁰ C. to 90 ⁰ C. Suitable materials which are particularly envisaged are fatty acids, particularly those having a carbon chain of 12 to 24 carbon atoms. Examples are lauric, myristic, palmitic, stark, arachidic and behenic acids and mixtures thereof. Sources of these fatty acids are coconut, topped coconut, palm, palm kernel, babassu and tallow fatty acids and partially or fully hardened fatty acids or distilled fatty acids. Other suitable water insoluble structurants include alkanols of 8 to 20 carbon atoms, particularly cetyl alcohol. These materials generally have a water solubility of less than 5 g/litre at 20 ⁰ C. Other structurants may include particulate solids such as talc, starch (e.g., maltodextrin) or clay. The relative proportions of the water soluble structurants and water insoluble structurants govern the rate at which the bar wears during use. The presence of the water-insoluble structurant tends to delay dissolution of the bar when exposed to water during use and hence retard the rate of wear.

Further, the composition can be made multicolored, e.g., striped, through the judicious use of dye as is well known in the art.

The benefit agents generally comprises about 0-25% by wt . of the composition, preferably 5-20%, and most preferably between 2 and 10%.

Finally, bar compositions of the invention comprise about 1 to 15%, preferably 2 to 12%, more preferably 3 to 12% by wt . Water. Bar compositions of the invention have pH of about 6 to 11, preferably above 7.

The essential benefit agents of the present invention can be added at any stage in the processing of the bar provided the component is not subjected to processing steps leading to its degradation The components may be added as the free acid or salt dependant on the pH of medium i.e. with a very alkaline active material the free acid may be added so that the salt is formed in the bar. In preparing the detergent bars of the present invention, the dicarboxylic acid, alpha- hydroxy acid and non-cationic surfactant components may be incorporated into the soap at any stage of processing into bar form, preferably by admixture with the previously prepared soap chips in the crutcher or, more preferably, the amalgamator. According to a further feature of the invention, the dicarboxylic acid and the alpha-hydroxy acid components are first dissolved or dispersed in the liquid or liquified surfactant (e.g. by heating up to about 90 ⁰ C if needed) and the resulting solution (or dispersion) then admixed with the fatty acid salt- containing soap

composition, followed by conventional extrusion and pressing into bar form. The surfactant included detergent composition of the present invention improves their solubility and lathering properties in use in water, especially cold, hard water, exerts an emollient or anti- irritation effect on the skin, and renders the soap composition more plastic and more readily and economically processed into bars. Pre-dissolving the dicarboxylic acid and the alpha-hydroxy acid in the surfactant further facilitates uniform mixing into the soap composition.

The soap bars may be prepared by either neutralization or saponification. If fatty acid is to be used, it may be introduced into the mixture a number of ways. The fatty acids, for example, may be added directly to the mixer and melted. A second approach to combining the ingredients begins with using pre- formed soap noodles and mixing the ingredients well below the melting temperature of the soap (e.g. 50 ⁰ C) . Pre-formed soap noodles may be added to a z- blade type mixer (or a similar type mixer which provides sufficient kneading action for blending the materials) and subsequently adding the salt of alpha-hydroxy acid and the salt of dicarboxylic acid, as described above. As long as the ingredients are mixed until homogeneous, the material may be cooled, milled, extruded and subsequently pressed.

The procedure for combining these materials is very flexible. One way of combining the ingredients is to weigh out a predetermined amount of soap noodles (formed from a conventional process by mixing ingredients, cooling and refining), warm and mix them to about 40 ⁰ C, add the salt -

hydroxy acid (e.g., sodium lactate) followed by the salt of dicarboxylic acid, e.g. Dipotassium sebacate) . The mass can then be milled and processed into bars.

The bar could be in the form of a single phase bar or a multiphasic bar, commonly also known as variegated detergent bars, which have at least 2 generally visually distinct phases in the bar, which could be e.g. in the form of co- extruded billets. Multicolor or multiphase soaps have been described by various terms that include variegated, marbled, striated, and striped.

Another way of preparing the formulation is to prepare the entire mass in a single pot under molten conditions. The bars described in this application can be prepared using manufacturing techniques described in the literature and known in the art for the manufacture of toilet soap bars. Examples of the types of manufacturing processes available are given in the book Soap Technology for the 1990' s (Edited by Luis Spitz, American Oil Chemist Society Champaign, and Illinois. 1990) . These broadly include: melt forming, extrusion/stamping, and extrusion, tempering, and cutting. A preferred process is extrusion and stamping because of its capability to economically produce high quality bars suitable as toilet soaps.

The invention may be put into practice in various ways and a number of specific embodiments will be described to illustrate the invention with reference to the accompanying examples.

All amounts and proportions referred to herein and in the appended claims are by weight unless otherwise indicated.

Experiment -1

Various detergent compositions 1-7 in the form of soap bars were made. The final composition of these bars is tabulated in the table-1 below, while the panel scores are tabulated in table-2.

Table-1

Soap noodles containing 80 parts non-lauric soap and 20 parts lauric soaps, had 77 % TFM, 16% moisture and volatiles and 0.4% alcohol insolubles. Ex-Jocil

Industries, India.

SLS is Sodium Lauryl Sulphate (90% purity) Ex-Galaxy

Surfactants

DMLO is Dimethyl Lauryl Amine oxide (28% aqueous solution)

Ex-Galaxy Surfactants

Sodium Lactate (60% aqueous solution) Ex Lactochem India

Dipotassium Sebacate powder Ex-FDL UK

Polymer beads - Polyethylene beads 100 mesh, from Micropowders INC USA.

Table-2

Method of scoring The soap bars were washed down under controlled conditions by a panel of 5 trained operators for 4 successive days, each operator handling each bar once a day. A single wash involved immersion of the tablet in about 2 litres of water (changed for every tablet) for 15 seconds and then turning and rubbing the tablet edgewise in the hand at 180 degrees, 40 times. The tablet was immersed for 15 seconds after the 20 ^th time and was twisted again at the end of the operation. The daily readings after drying and the reading on the last day were assessed for cracking on a scale of 0 -14 where 0 represents no cracking whereas 14 represents very severe cracking, with increasing degree of cracking. A cracking score of 0 is most desirable and is preferred over cracking scores of 0.1 or 0.2 and higher.

From the table-2 above, it is clear that when the compositions contained no surfactant or high (6%) surfactant, the cracking scores were un-acceptable (batch nos . 1, 2, 5 and 6) .

Whereas, batches within the invention 3, 4 and 7 show cracking score of 0.

An illustrative procedure for making detergent compositions in the form of milled-plodded and extruded soap bars is given below. The following ingredients were used for making the soap bars, as in table-3 below. All ingredients are in Kg.

Table-3

Soap noodles 910

Glycerin 5

SLS 25

DMLO 10

Parsol MCX 1

Sodium lactate 20

Di-potassium sebacate 15

Titanium dioxide 3

Tinopal 0.2

Extracts 1

Perfume 15

Polymer beads 1

Colorant 0.7

Total 1000

• Soap noodles containing 80 parts non-lauric soap and 20 parts lauric soaps, had 77 % TFM, 16% moisture and volatiles and 0.4% alcohol insolubles. Ex-Jocil Industries, India.

• Glycerin (99 %pure) Ex- Jocil Industries

• SLS is Sodium Lauryl Sulphate (90% purity) Ex-Galaxy Surfactants

• DMLO is Dimethyl Lauryl Amine oxide (28% aqueous solution) Ex-Galaxy Surfactants

• Sodium Lactate (60% aqueous solution) Ex Lactochem India

• Dipotassium Sebacate powder Ex-FDL UK • Polymer beads - Polyethylene beads 100 mesh, from Micropowders INC USA.

• Extracts - Mixture of Fruit and Turmeric extracts

(Extrapone Curcuma) and (Extrapone fruits) available from Symrise India

Process: The soap noodles were taken into a mixer and then mixed with SLS for 3 minutes. After it was converted to fine powder, DMLO and polymer beads were added followed by sodium lactate and Parsol MCX. The mass was mixed for 3 minutes and solid additives like Titanium dioxide, Tinopal, and

Dipotassium sebacate, were added to the mass. After mixing it for 2 minutes extracts were added and mixed for another 2 minutes. The colorants and perfume were added and mixed for 2 minutes. The composition was then milled followed by plodding and stamping.

The present invention thus provides an extrudable detergent composition comprising multiple benefit agents like alpha- hydroxy acids and dicarboxylic acids, which compositions, when extruded in bar form, remain resistant to wet-cracking, a situation, which otherwise is not acceptable to the consumer .

While the basic principle of the method of this invention has been illustrated and described herein, it will be appreciated by those skilled in the art that variations in

the disclosed arrangement, both as to its details and as to the organization of such details, may be made without departing from the spirit and scope thereof. Accordingly, it is intended that the foregoing disclosure and examples will be considered only illustrative of the principles of the invention and not construed in a limiting sense.