SOAP/DETERGENT BAR COMPOSITION AND MANUFACTURING PROCESS The invention relates to a synergistic composition of soap/detergent bars, and in particular soap/detergent bars for personal washing. It also relates to a process for the preparation of such soap/detergent bars for personal and/or fabric washing. The invention particularly relates to a low total fatty matter (TFM as defined below) soap/detergent bar comprising high levels of water and other liquid benefit agents, and a process for its manufacture.

Conventional detergent bars based on soap for personal washing usually contain over about 70% by weight TFM, the remainder being water (about 10-20%) and other ingredients such as colour, perfume, preservatives, etc. Structurants and fillers are also present in such compositions in small amounts, which replace some of the soap in the bar while retaining the desired hardness of the bar. Known fillers include starch, kaolin and talc.

Hard non-milled soap bars containing moisture of less than 35% are also available. These bars have a TFM of about 30-65%. The reduction in TFM has usually been achieved by the use of insoluble particulate materials and/or soluble silicates. Milled bars generally have a water content about 8-15%, and the hard non-milled bars have a water content of about 20-35%.

It is important to deliver sensory properties such as lather and skin feel, preferably by incorporating benefit agents in

the formulation without altering the processability and physical properties of the bar. Incorporation of other materials such as phosphates etc. in soap systems can create problems such as efflorescence, gritty feel, etc.

IN 176384 discloses a detergent composition with low TFM content having high ratio of water to TFM without affecting hardness, cleaning and lathering properties of the bar by the incorporation of up to 20% colloidal aluminium hydroxide (A-gel). The A-gel/TFM combination enables the preparation of bars with higher water content while using TFM at a lower level. In this patent, although the A-gel concentration disclosed is up to 20% by weight, the demonstration of the invention is restricted to the use of 7.5% by weight A-gel in combination with 40% TFM with an additional structurant such as 5% by weight of alkaline silicate.

IN 177828 discloses a process wherein, by providing a balanced combination of aluminium hydroxide and TFM, it is possible to prepare a low TFM bar having high water content but with satisfactory hardness. The patent teaches the generation of colloidal aluminium hydroxide in-situ by a reaction of fatty acid/fat with an aluminium containing alkaline material such as sodium aluminate to form bars which are obtained by plodding.

Our co-pending application 811/Bom/98 (corresponding to GB 9906834.8) discloses that use of A-gel from 9 to 16% by weight of the composition synergistically improves the processability, sensory and physical properties of low TFM bars.

In addition, our co-pending application WO 00/36075 discloses a process of preparing a low TFM bar that gives superior bar properties, utilising a reaction of fatty acid with an aluminium containing alkaline material such as sodium aluminate solution, that specifically has a solid content of 20 to 55% by weight, wherein the alumina (Al203) and sodium oxide (Na2O) are in a ratio of 0.5 to 1.55 by weight. These bars have improved hardness and smoother feel. This reaction can take place in a broader temperature range of 40 to 95°C.

Our application WO 01/42419 discloses a process of preparing a low TFM bar that gives superior bar properties comprising in situ reaction of phosphoric acid with an aluminium containing material such as sodium aluminate to generate aluminium hydroxide and a mix of orthophosphates. The sodium aluminate solution has a solid content of 20 to 55% by weight, and the alumina (Al203) to sodium oxide (Na2O) is in a ratio of 0.5 to 1.55 by weight. Bars produced using this process have a lower density relative to bars filled with conventional materials such as calcite, kaolin and talc, and improved physical properties, without interfering with the sensory properties. By this process it is possible to formulate bars that are suitable for both soft and hard water situations.

We have now found that further improved soap bars can be produced with a low TFM content having high ratio of water to TFM without affecting hardness, cleaning and lathering properties of the bar by the incorporation of alumina gel

and tetra sodium pyrophosphate decahydrate (TSPP) produced by the reaction of sodium aluminate and di sodium di hydrogen pyrophosphate, or sodium acid pyrophosphate (SAPP) as it is known commercially. The reaction is preferably carried out in the presence of a freshly formed soap, to ensure good dispersion of the pyrophosphate formed in the soap mix and hence minimise particle size, either with or without the glycerol removed. If the soap is formed by the reaction of sodium aluminate with an oil blend or with fatty acids the reaction to form TSPP is preferably carried out after the saponification stage is essentially complete.

Accordingly, the first aspect of the present invention comprises a low total fatty matter toilet soap bar composition comprising 40-78% by weight total fatty matter, 0.4-13% by weight colloidal alumina gel (as A1203), 0-23% by weight TSPP, expressed as the anhydrous salt, 0-15% by weight glycerol, and 7 to 30% by weight water including water of hydration.

If glycerol is being left in the soap base the extra aluminate to neutralise the SAPP may be added during the saponification stage, the excess aluminate being neutralised with SAPP after completion of the saponification reaction.

The ratio of TSPP to alumina gel in the final formulation may be varied within certain limits. To maximise the alumina ratio sodium aluminate is neutralised with the oil/fatty acid. To increase the proportion of TSPP requires the addition of SAPP that is neutralised with the required amount of alkali.

Preferably the weight ratio of A1203 to Na20 from the soap in the soap base noodles after adjusting their water content is in the range 0.05 : 1 to 1.75 : 1 by weight. The total content of free plus hydrated water is in the range 7-30% by weight.

Preferably, the amount of TSSP in the composition, expressed as anhydrous salt, is from 1% to 20% by weight. If the glycerol produced during saponification is left in place it will generally give a level of 0-10% by weight in the final formulation. Extra glycerol may be added to provide a specified level of glycerol if the amount produced by the saponification reaction is insufficient. The glycerol content of the final bar may be raised to a maximum of 15% by weight. Other additives conventionally present in soap bars may also be added.

The process of the invention can be carried out in any batch mixer conventionally used in soap/detergent manufacture and is preferably carried out in a high shear mixer. The preferred mixers include a 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 conventional paddle mixer, a helical screw agitator vessel or multi-head dosing pump/high shear mixer and spray drier combinations as in conventional processing.

According to a second aspect of the invention a process for preparing a low total fatty matter detergent bar comprises the steps of:

a. Making soap by reacting a mixture of one or more fats and/or fatty acids with alkaline aluminium-containing material and/or sodium hydroxide at a temperature of 60-150°C ; b. Optionally removing some or all of the glycerol from the soap mix from (a) if required. c. Further reducing the TFM of the neat soap if required, by in-situ neutralisation of an alkaline aluminium containing material with SAPP; d. Adjusting the water content of the soap base, by adding or removing water to/from the soap mixture, and cooling; e. converting the product of (d) into bars.

The term total fatty matter, referred to above and subsequently, usually abbreviated to TFM, is used to denote the percentage by weight of fatty acid and triglyceride residues present in the composition 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, caster 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 (all percentages by weight). 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% Ciao, 48% C12, 17% C14, 8% C16, 2% C18, 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.

According to a preferred aspect of the invention up to 50% by weight benefit agents such as non-soap surfactants, skin benefit materials such as moisturisers, emollients, sunscreens, or anti-ageing compounds can be incorporated at any step prior to step of milling. Alternatively certain of these benefit agents can be introduced as macro domains during plodding.

A typical suitable fatty acid blend consists of 5 to 30% by weight coconut fatty acids and 70 to 95% by weight 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.

The non-soap surfactants may be anionic, nonionic, cationic, amphoteric or zwitterionic, or a mixture thereof. 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 W-B sun-screens.

Other additives such as one or more water insoluble particulate materials such as talc, kaolin, polysaccharides such as starch or modified starches and celluloses may be incorporated.

At any stage of the process minor additives such as perfume, colour, preservatives, fillers and other conventional additives at 1 to 10 % by weight can be incorporated.

The composition according to the invention will preferably comprise detergent actives which are generally chosen from both anionic and nonionic 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 R3NO, 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 R3PO, 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 R2SO 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 dodecylmethyl-polyoxyethylene ammonium chloride and amine and imidazoline salts for e. g. primary, secondary and tertiary amine 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-solubilising 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.

The invention will now be further described by way of illustration only, with reference to the following non- limiting examples which amongst other things show comparative results of the composition prepared by the present invention and beyond the invention.

Example 1.

100 kg of a soap base was prepared in a ploughshare mixer by first adding 4.73 kg of 90% active alpha olefin sulphate (AOS), 0.85 kg sodium chloride and 38.81 kg of sodium aluminate solution containing 20. 5% by weight Na2O and 24. 4% by weight Al203. To this mixture was added 52.18 kg of molten distilled fatty acids (DFAs) at 90°C. The DFA's were allowed to saponify and then 0.12 kg of a 35% by weight solution of sodium EDTA and 0.35 kg of a 60% by weight solution of EHDP (etidronic acid) preservative were added and dispersed in the mix. To this was added 6.11 kg of SAPP. This was allowed to react with the excess sodium aluminate to form TSPP. Water was lost through evaporation due to the heat liberated during the reactions and the final water content of the mixture was adjusted to yield 100 kg of soap base of the following composition:- wt% Sodium soap 56.52 Sodium chloride 0.85 AOS 4.26 NaEDTA 0.04 EHDP 0.21 Al(OH)3 14.48 TSPP 10H2O 12.28 Free Water 11.36 (4.06 kg water lost during processing) Total 100.0

To 93.9 kg of this soap base was added 5.0 kg talc, 0.6 kg of perfume and 0.5 kg of titanium dioxide which were mixed in a z-blade mixer to yield 100 kg of final soap formulation. This was milled, extruded and stamped into soap bars.

Examples 2a-d.

The following soap bases were prepared by mixing ca. 100 kgs of a neat soap with the glycerol extracted at approximately 30% water and 0.5% salt with an appropriate quantity of SAPP slurried in a 2% brine solution at 80 to 90 degrees centigrade. To this mixture was added sufficient sodium aluminate solution containing 20% by weight Na20 and 20% by weight Al203 at 70 to 90°C to completely neutralise the SAPP. The reaction between the aluminate solution and the SAPP took place in situ and the alumina gel and TSPP formed were fully dispersed in throughout the soap. Dilute brine solution was added to the mixture to enable the soap/alumina gel/TSPP mixture to be pumped via heat exchangers to a vacuum dryer where the mixture was dried and cooled to about 40°C for subsequent finishing into soap bars.

A range of soap bases were made in this way to the following nominal compositions prior to finishing. 2a 2b 2c 2d A6025 A6028 A6030 A6043 wt% wt% wt% wt% Sodium soap 81. 3 73.8 67.2 60.3 Sodium chloride 0.5 0.5 0.5 0.5 NaEDTA 0. 02 0.02 0.02 0.02 EHDP 0. 02 0.02 0.02 0.02 Al (OH) 3 0. 9 1.7 2.5 3.3 TSPP 10H20 4.3 8.2 12.0 15.5 Free Water 13. 0 15.8 17.8 20.4 Total 100. 0 100.0 100.0 100.0

Example 3.

40.33 kg of soap base was prepared in a ploughshare mixer by adding 20 kg of an 80 parts tallow/20 parts coconut oil blend pre-heated to 90 degrees centigrade to the mixer. To this oil blend was added 14.8 kg of sodium aluminate solution, containing 20% by weight Na20 and 20% by weight Al203, that had been pre-heated to 90 degrees centigrade.

The mixture was allowed to react under agitation until the saponification of the triglyceride was essentially complete.

To the neat soap blend was added 2.1 kg of SAPP slurried in 3.4 kg water at 85 degrees centigrade. Mixing was continued for a further 30 minutes to ensure complete neutralisation of the SAPP with the excess sodium aluminate after saponification. Finally, 20g of a 40% by weight solution of NaEDTA and llg of a 60% by weight solution of EHDP were added and mixing continued for a further 5 minutes to ensure complete dispersion of the ingredients. A soap base of the following composition resulted. wt. % Soap 51.5 Glycerol 5.8 Aluminium hydroxide 11. 2 TSPP decahydrate 10.5 NaEDTA 0.019 EHDP 0. 016 Water 21. 0