Title of Invention	IMPROVED DETERGENT BAR AND PROCESS OF MANUFACTURE
Abstract	IMPROVED DETERGENT BAR AND PROCESS OF MNUFACTURE

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FORM -2 THE PATENTS ACT, 1970 (39 of 1970) COMPLETE SPECIFICATION (See Section 10) IMPROVED DETERGENT BAR AND PROCESS OF MANUFACTURE HINDUSTAN LEVER LIMITED, a company incorporated under the Indian Companies Act, 1913 and having its registered office at Hindustan Lever House, 165/166, Backbay Reclamation, Mumbai -400 020, Maharashtra, India The following specification particularly describes the nature of the invention and the manner in which it is to be performed. Technical Field: The invention relates to a synergistic composition of soap/detergent bars for personal and/or fabric washing. It also relates to a process for the preparation of such soap/detergent bars for personal and/or fabric washing. In particular, the invention is directed towards the suppression of efflorescence in detergent bars comprising a detergent active and one or more phosphates. Background and Summary: Conventional detergent bars for personal and fabric washing usually contain a detergent active, water and other ingredients such as colour, perfume, preservatives, etc. Structurants and fillers are also present in such compositions, which replace some of the active in the bar while retaining the desired hardness of the bar. A few known structurants and fillers include starch, kaolin, silicates and talc. Bars meant for personal wash are based on soap and are either milled or non-milled. Hard non-milled soap bars contain 20-35% moisture while milled bars have a moisture content of 8-15%. Unstructured hard non-milled soap bars have a total fatty matter (TFM) of 55-60% while unstructured milled soap bars have a TFM of 75-80%. Reduction in TFM requires that the bar be "structured" by the use of insoluble particulate materials like kaolin and talc and/or soluble silicates. Orthophosphates and pyrophosphates are used in soap bar compositions. The phosphates help in reducing TFM, increasing the moisture content of the bar and act as builders. While it is advantageous to incorporate phosphates, their use in the soap system creates problems like efflorescence that impairs the visual appearance of the bar. US6310016 (Unilever Home & Personal Care USA) discloses a low total fatty matter detergent bar composition comprising 15-70% total fatty matter, 0.5-40% colloidal aluminium hydroxide-phosphate complex and 10-50% water wherein the phosphate is generated from orthophosphoric acid. US 4297230 (The Procter & Gamble Company) is directed towards transparent soap bar compositions comprising potassium soap and chloride ions. The potassium soap and chloride ions form crystals which impair the appearance of the bar. To prevent crystallisation, electrolytes are added. Electrolytes suitable for the invention include simple and condensed potassium phosphates as well as electrolytes chosen from sodium and/or potassium citrates, acetates, formates and tartarates. Thus, the prior art does not address the problem of efflorescence in soap bars due to the presence of phosphates. Further, soap bars containing phosphates have a higher pH than conventional soap bars. The high pH causes problems like skin irritation and dryness, particularly amongst users with sensitive skin. The pH is conventionally adjusted by adding free fatty acid. These "superfatted" phosphate structured bars show enhanced efflorescence. By superfatted is meant bars that contain free fatty acid. The aforesaid problem is also not addressed in the prior art. The present inventors have now found that a detergent bar comprising the detergent active, phosphates and a water soluble organic salt shows synergistic benefits of minimal or no efflorescence during storage. In particular, efflorescence is significantly reduced for soap bars that are superfatted and phosphate structured. The invention also relates to a process to make these bars. Brief Description of the Invention: The present invention relates to synergistic detergent bar compositions comprising a detergent active, one or more hydrated phosphates and one or more water soluble salts of organic acids. The detergent bar of the invention shows minimal or no efflorescence. Preferably the detergent bar comprises soap. In particular, the invention is useful for "superfatted" soap bars comprising soap, hydrated phosphates and water soluble salts of organic acids. The invention also relates to a process to make the synergistic detergent bars of the invention. Detailed Description of the Invention: According to the first aspect of the invention, there is provided a synergistic detergent bar composition comprising: 1. from 15 to 70% by weight of one or more detergent actives 2. one or more hydrated phosphates 3. from 0.1 to 5% by weight of at least one water soluble salt of an organic carboxylic acid 4. from 10 to 55% by weight of water 5. balance other optional ingredients as herein described wherein the anhydrous component of hydrated phosphate is upto 20% phosphorus pentoxide (P2O5). Preferably the detergent active comprises a soap. The phosphate and the soap may be generated in situ consecutively or simultaneously or prepared independently and mixed. Thus according to the preferred aspect of the invention, there is provided a synergistic detergent bar composition comprising: 1. from 15 to 70% by weight of one or more detergent actives, wherein at least 75% of the detergent active is soap 2. one or more hydrated phosphates 3. from 0.1 to 5% by weight of at least one water soluble salt of an organic carboxylic acid 4. from 10 to 55% by weight of water 5. balance other optional ingredients as herein described wherein the anhydrous component of hydrated phosphate is upto 20% P2O5. It is particularly preferred that the alkali used in the soap formation contains aluminium. Sodium aluminate is especially preferred. According to a further preferred aspect of the invention, there is provided a synergistic detergent bar composition comprising: 1. from 15 to 70% by weight of one more detergent actives, wherein at least 75% of the active is soap 2. one or more hydrated phosphates 3. from 0.5 to 30% by weight of colloidal aluminium hydroxide 4. from 0.1 to 5% by weight of at least one water soluble salt of an organic carboxylic acid 5. from 10 to 55% by weight of water 6. balance other optional ingredients as herein described wherein the anhydrous component of hydrated phosphate is upto 20% P2O5. It is further preferred that upto 5% free fatty acid is present in the detergent bar of the invention. Especially preferred fatty acids have a carbon chain length of C8-C14. According to a second aspect of this invention there is provided an improved process for preparing a synergistic detergent bar composition comprising from 15 to 70% by weight of one or more detergent actives one or more hydrated phosphates from 0.1 to 5% by weight of at least one water soluble salt of an organic carboxylic acid from 10 to 55% by weight of water balance other optional ingredients as herein described wherein the anhydrous component of hydrated phosphate is upto 20% P2O5. which process comprises the steps of: a. generating phosphate by reacting phosphorus containing mineral acid with an alkali in presence of the detergent active precursor at a temperature between 25°C to 105°C to obtain a mixture of phosphate and neutralised detergent active; b. generating in or adding to the neutralised detergent active the water soluble salt of an organic carboxylic acid; c. adding if desired, other detergent actives and minor additives such as herein described to the detergent mixture d. converting the product of step (c) into bars by conventional method. According to a preferred aspect of this invention there is provided an improved process for preparing a synergistic detergent bar composition comprising from 15 to 70% by weight one or more detergent actives, wherein at least 75% of the active is soap one or more hydrated phosphates from 0.1 to 5% by weight of at least one water soluble salt of an organic carboxylic acid from 10 to 55% by weight of water and balance other optional ingredients as herein described wherein the anhydrous component of hydrated phosphate is upto 20% P2O5. which process comprises the steps of: a. generating phosphate by reacting phosphorus containing mineral acid with an alkali in presence of soap and optionally other detergent active precursors at a temperature between 25°C to 105°C to obtain a mixture of phosphate and soap; b. generating in or adding to the soap the water soluble salt of an organic carboxylic acid c. adding if desired, other detergent actives and minor additives such as herein described to the soap mixture d. converting the product of step (c) into bars by conventional method. It is particularly preferred according to one embodiment of the invention that one or more detergent active precursors and the phosphorus containing mineral acid are reacted with an alkali to simultaneously form the neutralised active and the phosphate. According to another preferred embodiment the neutralised active is first formed by reacting one or more detergent active precursors with an alkali followed by mixing the neutralised active with the phosphorus containing mineral acid and if required, alkali to obtain the mixture of neutralised active and phosphate. According to yet another preferred embodiment, a) the neutralised active is formed by reacting one or more detergent active precursors with an alkali and b) the phosphate is formed by reacting a phosphorus containing mineral acid with an alkali and the neutralised active and phosphate so formed are mixed. Preferably, the detergent active precursors comprise fatty acids and/or fat. The alkali used for soap formation can be any conventional alkali e.g. caustic soda, soda ash, caustic potash, sodium aluminate etc. More preferred alkalis include caustic soda and/or an aluminium containing alkali (e.g. sodium aluminate). Sodium aluminate with a solid content of 20 to 55% wherein the Al2O3 to Na2O is in a ratio of 0.5 to 1.55 by weight is especially preferred. Preferred phosphorus containing mineral acids are orthophosphoric acid and sodium acid pyrophosphate (disodium dihydrogen pyrophosphate). When an aluminium containing alkali is used, it is especially preferable to maintain a weight ratio of aluminium oxide (AI2O3) to phosphorus containing mineral acid in the range 0.40 to 2.40. Preferably the detergent bar of the invention has upto 5% free fatty acid. The free fatty acid can be added at any step during the process of soap making as described above. Alternatively, it can be generated in-situ by adding a suitable material that will break down the soap to generate free fatty acid. Examples of such materials include citric acid, adipic acid etc. The materials are preferably added after step (c) of the process described above. DETERGENT ACTIVES The composition according to the invention will comprise one or more detergent actives which are generally chosen from anionic, nonionic, cationic, amphoteric or zwitterionic detergent actives. Preferably the detergent active is an anionic active, more preferably a soap. By the term soap is meant neutralised total fatty matter. Preferably, at least 75% of the detergent active is soap. Total Fatty Matter The term total fatty matter, usually abbreviated to TFM is used to denote the percentage by weight of fatty acid and triglyceride residues present without taking into account the accompanying cations. For a soap having 18 carbon atoms, an accompanying sodium cation will generally amount to about 8% by weight. Other cations may be employed as desired, for example zinc, potassium, magnesium, alkyl ammonium and aluminium. The term soap denotes salts of carboxylic fatty acids. The soap may be derived from any of the triglycerides conventionally used in soap manufacture-consequently the carboxylate anions in the soap may contain from 8 to 22 carbon atoms. The soap may be obtained by saponifying a fat and/or a fatty acid. The fats or oils generally used in soap manufacture may be such as tallow, tallow stearines, palm oil, palm stearines, soya bean oil, fish oil, castor oil, rice bran oil, sunflower oil, coconut oil, babassu oil, palm kernel oil, and others. In the above process the fatty acids are derived from oils/fats selected from coconut, rice bran, groundnut, tallow, palm, palm kernel, cotton seed, soybean, castor etc. The fatty acid soaps can also be synthetically prepared (e.g. by the oxidation of petroleum or by the hydrogenation of carbon monoxide by the Fischer-Tropsch process). Resin acids, such as those present in tall oil, may be used. Naphthenic acids are also suitable. 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% C 8 , 7% C 10 , 48% C 12 , 17% C 14 , 8% C 16 , 2% C 18 , 7% oleic and 2% linoleic acids (the first six fatty acids listed being saturated). Other sources having similar carbon chain length distributions, such as palm kernel oil and babassu kernel oil, are included within the term coconut oil. A typical suitable fatty acid blend consists of 5 to 30% coconut fatty acids and 70 to 95% fatty acids ex-hardened rice bran oil. Fatty acids derived from other suitable oils/fats such as groundnut, soybean, tallow, palm, palm kernel, etc. may also be used in other desired proportions. Other Detergent Actives Suitable anionic detergent active compounds are water soluble salts of organic sulphuric reaction products having in the molecular structure an alkyl radical containing from 8 to 22 carbon atoms, and a radical chosen from sulphonic acid or sulphuric acid ester radicals and mixtures thereof. Examples of suitable anionic detergents are sodium and potassium alcohol sulphates, especially those obtained by sulphating the higher alcohols produced by reducing the glycerides of tallow or coconut oil; sodium and potassium alkyl benzene sulphonates such as those in which the alkyl group contains from 9 to 15 carbon atoms; sodium alkyl glyceryl ether sulphates, especially those ethers of the higher alcohols derived from tallow and coconut oil; sodium coconut oil fatty acid monoglyceride sulphates; sodium and potassium salts of sulphuric acid esters of the reaction product of one mole of a higher fatty alcohol and from 1 to 6 moles of ethylene oxide; sodium and potassium salts of alkyl phenol ethylene oxide ether sulphate with from 1 to 8 units of ethylene oxide molecule and in which the alkyl radicals contain from 4 to 14 carbon atoms; the reaction product of fatty acids esterified with isethionic acid and neutralised with sodium hydroxide where, for example, the fatty acids are derived from coconut oil and mixtures thereof. The preferred water-soluble synthetic anionic detergent active compounds are the alkali metal (such as sodium and potassium) and alkaline earth metal (such as calcium and magnesium) salts of higher alkyl benzene sulphonates and mixtures with olefin sulphonates and higher alkyl sulphates, and the higher fatty acid monoglyceride sulphates. Suitable nonionic detergent active compounds can be broadly described as compounds produced by the condensation of alkylene oxide groups, which are hydrophilic in nature, with an organic hydrophobic compound which may be aliphatic or alkyl aromatic in nature. The length of the hydrophilic or polyoxyalkylene radical which is condensed with any particular hydrophobic group can be readily adjusted to yield a water-soluble compound having the desired degree of balance between hydrophilic and hydrophobic elements. Particular examples include the condensation product of aliphatic alcohols having from 8 to 22 carbon atoms in either straight or branched chain configuration with ethylene oxide, such as a coconut oil ethylene oxide condensate having from 2 to 15 moles of ethylene oxide per mole of coconut alcohol; condensates of alkylphenols whose alkyl group contains from 6 to 12 carbon atoms with 5 to 25 moles of ethylene oxide per mole of alkylphenol; condensates of the reaction product of ethylenediamine and propylene oxide with ethylene oxide, the condensate containing from 40 to 80% of polyoxyethylene radicals by weight and having a molecular weight of from 5,000 to 11,000; tertiary amine oxides of structure R 3 NO, where one group R is an alkyl group of 8 to 18 carbon atoms and the others are each methyl, ethyl or hydroxyethyl groups, for instance dimethyldodecylamine oxide; tertiary phosphine oxides of structure R 3 PO, where one group R is an alkyl group of from 10 to 18 carbon atoms, and the others are each alkyl or hydroxyalkyl groups of 1 to 3 carbon atoms, for instance dimethyldodecylphosphine oxide; and dialkyl sulphoxides of structure R 2 SO where the group R is an alkyl group of from 10 to 18 carbon atoms and the other is methyl or ethyl, for instance methyltetradecyl sulphoxide; fatty acid alkylolamides; alkylene oxide condensates of fatty acid alkylolamides and alkyl mercaptans. It is also possible to include cationic, amphoteric or zwitterionic detergent actives in the compositions according to the invention. Suitable cationic detergent actives that can be incorporated are alkyl substituted quaternary ammonium halide salts e.g. bis (hydrogenated tallow) dimethylammonium chlorides, cetyltrimethyl ammonium bromide, benzalkonium chlorides and dodecylmethylpolyoxyethylene ammonium chloride and amine and imidazoline salts for g. primary, secondary and tertiary £mine hydrochlorides and imidazoline hydrochlorides. Suitable amphoteric detergent-active compounds that optionally can be employed are derivatives of aliphatic secondary and tertiary amines containing an alkyl group of 8 to 18 carbon atoms and an aliphatic radical substituted by an anionic water-solubilizing group, for instance sodium 3-dodecylamino-propionate, sodium 3-dodecylaminopropane sulphonate and sodium N-2-hydroxydodecyl-N-methyltaurate. Suitable zwitterionic detergent-active compounds that optionally can be employed are derivatives of aliphatic quaternary ammonium, sulphonium and phosphonium compounds having an aliphatic radical of from 8 to 18 carbon atoms and an aliphatic radical substituted by an anionic water- solubilising group, for instance 3-(N-N-dimethyl-N-hexadecylammonium) propane-1 -sulphonate betaine, 3-(dodecylmethyl sulphonium) propane-1- sulphonate betaine and 3-(cetylmethylphosphonium) ethane sulphonate betaine. SALT OF ORGANIC CARBOXYLIC ACID The detergent bar of the invention essentially comprises one or more water soluble salts of organic carboxylic acids. Organic carboxylic acids suitable for the invention include C1-C10 carboxylic acids. Preferred salts include the alkali or alkaline earth metal salts of formic, acetic, propionic, citric, lactic and tartaric acid. Especially preferred salts are sodium and/or potassium formates, acetates, citrates, lactates and tartarates. Most preferred salts are chosen from sodium formate, sodium aceae, sodium citrate, sodium lactate and sodium tartarate. OPTIONAL INGREDIENTS Other conventional ingredients like moisturisers, emollients, sunscreens, skin lightening agents, perfume, anti-microbials, anti perspirants, natural extracts, anti-ageing compounds etc. are incorporated at any step prior to step of milling. Alternatively certain of these benefit agents are introduced as macro domains during plodding. Examples of moisturisers and humectants include polyols, glycerol, cetyl alcohol, carbopol 934, ethoxylated castor oil, paraffin oils, lanolin and its derivatives. Silicone compounds such as silicone surfactants like DC3225C (Dow Corning) and/or silicone emollients, or silicone oil (DC-200 Ex-Dow Corning) may also be included. Suitable sun¬screens include 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 LIV¬ES sun- screens. FILLERS While it is preferred not to use conventional fillers like kaolin, china clay, talc, silicates, starch etc., these may however be incorporated into the detergent bar of the invention. PROCESS OF MAKING DETERGENT BAR The process of the invention comprises the steps of a. generating phosphate by reacting phosphorus containing mineral acid with an alkali in presence of the detergent active precursor at a temperature between 25°C to 105°C to obtain a mixture of phosphate and neutralised active; b. generating in or adding to the neutralised active the water soluble salt of an organic acid c. adding if desired, other detergent actives and minor additives such as herein described to the soap mixture d. converting the product of step (c) into bars by conventional method. The mixture of phosphate and neutralised active can be obtained by any of the following methods : 1) generating the phosphate and the neutralised active consecutively (either the phosphate or the neutralised active can be generated first) 2) generating the neutralised active and phosphate simultaneously or 3) by generating the neutralised active and phosphate separately and then mixing the same. When a non-ionic surfactant is used in the process of the invention, neutralisation is not required. The sequence of generation of the phosphate and the surfactant remain the same as steps 1), 2) and 3). When an oil/fat is neutralised to generate the soap, glycerine is formed. In the process of the invention, the glycerine may be retained in the soap or may be removed. The water soluble organic carboxylic acid may be added or generated prior to the neutralisation of the detergent active or at any step after the neutralisation of the active. Other optional ingredients as described may be added in a suitable amount at any step of the process of making the detergent bar. The process of the invention is carried out in any mixer conventionally used in soap/detergent manufacture. High shear kneading mixers suitable for the invention include ploughshare mixer, mixers with kneading members of Sigma type, multi-wiping overlap, single curve or double arm. The double arm kneading mixers can be of overlapping or the tangential design. Alternatively the invention can be carried out in a helical screw agitator vessel or multi-head dosing pump/high shear mixer and spray drier combinations, as in conventional processing. The invention will now be further described by way of illustration only, with reference to the following non-limiting examples which amongst other things shows comparative results of the composition prepared by the present invention and beyond the invention. EXAMPLES : Examples 1 to 5 The process of making the soap bars Examples 1-5 is as given below : A mixture of fatty acids at 80-85°C and alpha olefin sulphonate (AOS) were taken into a ploughshare mixture. The fatty acids were neutralised with an alkali solution. For Example 1, caustic soda was used for neutralisation, for Examples 2-5, 45% sodium aluminate solution was used. Sodium acetate was then added in Examples 1-5. A phosphorus containing mineral acid was then added. For Examples 1-3, phosphoric acid was used. For Examples 4-5, sodium acid pyrophosphate was used. Other optional components were added and additional water was added to obtain a free moisture content6 of about 14% in the ploughshare mixer. The soap mass was then passed through a chilled drum and noodler to produce soap noodles. The noodles were then passed through a sigma mixer, mixed with perfume, colour and opacifier and passed twice through a triple roll mill. The milled chips were plodded under vacuum and formed into billets. The billets were cut and stamped into tablets. The tablets were then packaged in conventional wrappers and stored at three different conditions : 1. 40-45 degree centigrade and at 35-40% relative humidity for a period of 12 weeks (hot and dry - HD) 2. 40-45 degree centigrade and 75-80% relative humidity for a period of 12 week (hot and humid -HH) 3. 25-30 degree centigrade and at 55-65% relative humidity for a period of 12 weeks (ambient conditions - AC) The physical appearance of the tablets was assessed after 12 weeks using a 0 - 4 scale 0.5 denoted no visible change in the soap surface while 4 denoted extremely dense efflorescence all over the tablet. Any rating above 0.75 would result in a visually unappealing bar. The composition of the bars within and outside the invention and the efflorescence rating for the bars is presented in Table 1. Table 1 : 1 2 3 4 5 Soap 44 44 44 44 44 AOS 4 4 4 4 4 Aluminium Hydroxide 0 16.5 15.5 15.5 15.5 Sodium Orthophosphate 16 9.5 8.5 0 0 Tetra sodium pyrophosphate 0 0 0 12 12 Sodium Chloride 0 0 0 0 0 Sodium Acetate 1.5 1.5 1.5 1.5 1.5 Free Fatty acid 0 0 2 0 1 Minor ingredients 1.5 1.5 1.5 1.5 1.5 Efflorescence HD 0.5 0.5 0.5 0.5 0.5 HH 0.5 0.5 0.5 0.5 0.5 AC 0.5 0.5 0.5 0.5 0.5 The data shows that the bars of the invention (Examples 1-5), comprising sodium acetate, had a good visual appearance and did not show efflorescence Even for bars that contained free fatty acid, that increases efflorescence, the addition of sodium acetate resulted in bars with no efflorescence. Thus the present invention provides for synergistic phosphate structured detergent bars that show minimal or no efflorescence. WE CLAIM 1. A detergent bar composition comprising : a. from 15 to 70% by weight of one or more detergent actives; b. one or more hydrated phosphates; c. from 0.1 to 5% by weight of at least one water soluble salt of an organic carboxylic acid; and d. from 10 to 55% by weight of water; wherein the anhydrous component of hydrated phosphate comprises 0.1 to 25% phosphorus pentoxide (P2O5). 2. A detergent bar composition as claimed in claim 1 wherein the detergent active comprises at least 75% soap. 3. A detergent bar composition as claimed in claim 1 or claim 2 wherein the organic carboxylic acid is a C1-C10 carboxylic acid. 4. A detergent bar composition as claimed in claim 3 wherein the salt of the organic carboxylic acid an alkali or alkaline earth metal salt. 5. A detergent bar composition as claimed in claim 1 wherein the salt of the organic carboxylic acid selected from sodium formate, sodium acetate, sodium citrate, sodium lactate and sodium tartazate. 6. A detergent bar composition as claimed in any one of the preceding claims wherein the bar additionally comprises from 0.5 to 30% by weight of colloidal aluminium hydroxide. 7. A detergent bar composition as claimed in any one of the preceding claims wherein the bar additionally comprises up to 5% free fatty acid. 8. A detergent bar composition as claimed in any one of the preceding claims comprising the steps of: a) generating a neutralised detergent active by reacting a detergent active processor with an alkali and generating phosphate by reacting phosphorous containing mineral acid with an alkali at a temperature between 25°C and 105°C to obtain a mixture of phosphate and neutralised detergent active; b) generating in or adding to the neutralised detergent active the water soluble salt of an organic carboxylic acid; c) adding if desired, other detergent actives and minor additives to the detergent mixture; and d) converting the product of step (c) into bars by conventional method. 9. A process as claimed in claim 8 wherein one or more detergent active precursors and the phosphorus containing mineral acid are reacted with an alkali to simultaneously form the neutralised active and the phosphate. 10. A process as claimed in claim 8 wherein the neutralised active is first for4med by reacting one or more detergent active precursor with an alkali followed by mixing the neutraliseD active with the phosphorous containing mineral acid and if required, alkali to obtain the mixture of neutralised active and phosphate. 11. A process as claimed in claim 8 wherein the neutralised active is formed by reacting one or more detergent active precursors with an alkali; the phosphate is formed by reacting a phosphorus containing mineral acid with an alkali; and the neutralised active and phosphate formed are mixed. 12. A process as claimed in any one of claims 8 to 11 wherein the alkali comprises caustic soda and/or an aluminium containing alkali. 13. A process as claimed in claim 12 wherein the aluminium containing alkali is sodium aluminate. 14. A process as claimed in claim 13 wherein the sodium aluminate has a solid content of 20 - 55% and the AL2o3 to Na2o ratio is in the range 0.5 to 1.55 by weight. 15. A process as claimed in claim any one of claims 8 to 14 wherein the phosphorus containing mineral acids are orthophosphoric acid and sodium acid pyrophosphate (disodium dihydrogen pyrophosphate). Dated this 13th day of February 2002 S.. MAJUMDAR OF S.MAJUMDAR & CO. Applicant"s Agents

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