WO2002066588A2

WO2002066588A2 - Detergent bar and process for its manufacture

Info

Publication number: WO2002066588A2
Application number: PCT/EP2002/001246
Authority: WO
Inventors: Benjamin Rajapandian
Original assignee: Unilever N.V.; Unilever Plc; Hindustan Lever Ltd
Priority date: 2001-02-20
Filing date: 2002-02-05
Publication date: 2002-08-29
Also published as: BR0207334A; WO2002066588A3; AU2002249188A1; ZA200305801B

Abstract

A process for the preparation of a detergent bar, the process comprising the steps of (a) admixing in any order an acid precursor of a detergent active, an alkaline material for at least partially, preferably totally, neutralising the acid precursor, at least one hydroxy and/or amino group containing polymer, a boron containing compound, sodium aluminosilicate and/or generating reactants for generating sodium aluminosilicate in situ by allowing a source of monomeric aluminium to condense with a silicate anion, and optionally if desired, one or more other materials selected from other detergent actives, builders, fillers and minor ingredients; and(b) converting the admixed components resulting from (a), into a detergent bar.

Description

DETERGENT BAR AND PROCESS FOR ITS MANUFACTURE

Technical Field

The invention relates to a detergent bar, particularly, although not exclusively, for fabric washing or hard surface cleaning. It also relates to a process for manufacture of the bar. This invention particularly relates to an improved process for preparing a low density detergent bar comprising high levels of water and with good physical and sensorial attributes.

Background to the Invention

Fabric washing compositions contain, as an essential ingredient, a surfactant system whose role is to assist in removal of soil from the fabric and its suspension in the wash liquor. Detergent bars require an acceptable physical strength so that they retain their structural integrity during handling, transport and use. The hardness of the bars, at the time of manufacture and subsequently, is an especially important property. The water content in the detergent bars is generally maintained around 6%. The binders and fillers used in non-soap detergent (NSD) bars are typically minerals which generally exhibit wide variability in quality, by virtue of the fact that they are mined. The minerals are also responsible for the unattractive base colour of NSD bars and contribute significantly to mush and sog during use. The low moisture content coupled with the use of high proportion of minerals result in NSD bars with high density making them considerably smaller. Commercially available detergent bars contain detergent active components and detergent builders, fillers, structurants, hardeners together with optional components for example abrasives, perfumes , colour and bleaching agents. Commercial hard surface cleaning compositions typically comprise, one or more surfactants and a plurality of abrasives dispersed therein. Combinations of these together with electrolytes are generally used to form a suspending system as is well known in the art.

In fabric washing, where the active constitutes predominantly non-soap surfactants, it is important to deliver superior sensory properties such as lather, bar feel, skin feel, colour of the bar, without altering the processability and physical properties of the bar.

It would be essential to process the formulations using the existing equipment to enable products to be processed by the conventional methods of manufacture and without altering the throughput.

US-A-3, 708,425 teaches a detergent bar containing about 5 to 6% by wt. puffed borax. This work specifically called for puffed borax or other puffed salts to which the user properties of the bar are attributed. The puffed borax is compositionally different than borax or other boron-containing compounds of the invention.

US-A-3,798,181 teaches enzymatic detergent bars containing 10-40% synthetic detergent, o.5-5% enzymes, 5-40) binder (e.g. to help retain water), 20-60% inorganic builder and 12-25% water. Borax may be used as possible inorganic builder.

JP-A-50069240 discloses toilet deodorants that contain poly(vinyl alcohol), borax or boric acid, surfactant (e.g. Na Laurylsulphate), colourant and perfume.

The present invention relates to a process for manufacture of low density detergent compositions that have high levels of water by generating a boron hydroxy polymer gel in-situ, together with aluminosilicate structuring. It also relates to the resultant bar. Definition of the invention

A first aspect of the present invention provides a process for the preparation of a detergent bar, the process comprising the steps of

(a) admixing in any order an acid precursor of a detergent active, an alkaline material for at least partially, preferably totally, neutralising the acid precursor, at least one hydroxy and/or amino group containing polymer, a boron containing compound, sodium aluminosilicate and/or generating reactants for generating sodium aluminosilicate in situ by allowing a source of monomeric aluminium to condense with a silicate anion, and optionally if desired, one or more other materials selected from other detergent actives, builders, fillers and minor ingredients; and

(b) converting the admixed components resulting from (a), into a detergent bar.

In the process according to the first aspect of the present invention, in step (a), any of the materials incorporated into the admixture may be incorporated simultaneously with one or more of the other materials. Any material may optionally also be incorporated not as a single batch or stream but as two or more separate streams or batches.

Step (b) may be effected by any conventional means such as plodding and cutting or stamping, casting or injection moulding.

Step (a) of the process according to the present invention is particularly suited to producing a detergent bar composition in accordance with the second aspect of the present invention and which comprises:- from 5% to 70%, preferably from 15% to 30% by weight of detergent active;

from 0.5% to 30%, preferably from 5% to 15% by weight of boron- hydroxy polymer gel;

from 1 % to 15%, preferably from 2% to 10% by weight of aluminosilicate;

from 5% to 40%, preferably from 6% to 25% by weight water;

from 0% to 30%, preferably from 5% to 20% by weight detergent builder; and

from 0% to 60%, preferably from 10% to 40% by weight inorganic particulates.

This composition may then be converted to a bar of substantially the same composition by means of step (b) of the first aspect of the invention.

A third aspect of the present invention relates to a process for the preparation of low density bars with high water content, the process comprising the steps of:

(a) reacting a precursor of a detergent active with an alkaline material;

(b) adding a mixture of at least one hydroxy bearing polymer and a boron containing compound;

(c) generating in situ sodium aluminosilicate by allowing a source of monomeric aluminium to condense with a silicate anion; (d) adding if desired, other detergent actives, builders, fillers and minor ingredients; and

(e) converting the product into bars by a conventional method, the ingredients being incorporated in such amounts as to provide a bar composition comprising:

from 5% to 70%, preferably from 15% to 30% by weight of detergent active;

from 1 %) to 15%, preferably from 2% to 10% by weight of aluminosilicate;

from 5% to 40%, preferably from 6% to 25% by weight water;

from 0% to 30%, preferably from 5% to 20% by weight detergent builder; and

from 0% to 60%, preferably from 10% to 40% by weight inorganic particulates.

Detailed description of the Invention

It is essential for the process of the present invention that for the manufacture of low density detergent compositions with high levels of water, to generate in situ boron hydroxy polymer gel along with aluminosilicate as the structuring system. The acid precursor is preferably selected from anionic surfactant acids, fatty acids, and mixtures thereof. Preferred anionic surfactants and fatty acids/soaps are described in more detail hereinbelow.

It is particularly preferred that the alkaline material used to form the detergent active is an aluminium containing alkaline material and more preferably the aluminium containing alkaline material is sodium aluminate, preferably having a solid content of 20% to 55% by weight where in the AI2O3 to Na₂O is in a ratio of 0.5 to 1.55 by weight. According to a more preferred aspect of the invention, the neutralisation of the detergent active is carried out by reacting one or more precursors of detergent active and at least one carboxylic acid with sodium aluminate in order to generate amorphous alumina species. The carboxylic acid mentioned are those which have an equivalent weight less than 150 may be selected from aliphatic monocarboxylic acids that are not fatty acids and their polymers and more preferably they are C1 to C5 carboxylic acids and their polymers. Other suitable carboxylic acids are aliphatic or aromatic di-, tri-, or polycarboxylic acids and hydroxy- and amino carboxylic acids.

It is preferred that the weight ratio of the acid precursor of detergent active and the carboxylic acid is in the range 1 :1 to 60:1.

Boron-polymer gel

The boron-polymer gel is generated by reaction of a boron containing compound such as borax or boric acid with a hydroxy and/or amino containing polymer, for example selected from poly(vinyl alcohol), poly(vinyl acetate) or any other polymer (degree of polymerisation preferably in the range of 100- 5000) with reactive hydroxyl or amino (electron-donating) groups. In most cases, the reaction is preferably effected in the presence of a cross-linking agent. The cross-linking agent may be an electron accepting metal or metallike atom such as boron. The reaction between the boron containing compound and the hydroxy and/or amino containing polymer is preferably carried out in a mole ratio 0.1 to 15. The boron-hydroxy and/or amino polymer gel is preferably generated after forming the detergent active.

Aluminosilicate structuring system

The aluminosilicate inorganic particulate structurant may be generated in situ using generating reactants comprising a source of monomeric aluminium and a silicate anion able to condense with the source of monomeric aluminium. The preferred components used for the generation of the structurants are aluminium sulphate and alkaline sodium silicate. Additionally or alternatively, it is also possible to incorporate readily available sodium alumino-silicate into the formulation. It is highly preferred that the aluminosilicate is generated or incorporated after the formation of boron-hydroxy polymer gel.

Apparatus

The process according to the first or third aspect of the present invention is preferably carried out in any mixer conventionally used in soap-detergent manufacture and is preferably a high shear kneading mixer. The process may be carried out may be effected using either continuous or batch mixing. The preferred mixers 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 tangential in 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. Detergent active

The detergent active used in the process may be soap or non-soap surfactants. The term total fatty matter, usually abbreviated to TFM, is used to denote the percentage by weight of fatty acid and triglyceride residues present in soaps 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 b e 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% C₈, 7% Cιo, 48% C12, 17% C14, 8% Cιβ, 2% Ciβ, 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.

Fatty acid

A typical fatty acid blend consisted 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.

Non-Soap detergents

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 or 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 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 a sodium and potassium) and alkaline earth metal (such as calcium and magnesium) salts of higher alkyl benzene sulphonates (LAS) 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 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 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 quartemary ammonium halide slates e.g. bis (hydrogenated tallow) dimethylammonium chlorides, cetyltrimethyl ammonium bromide, benzalkonium chlorides and dodecylmethylpolyoxyehtylene ammonium chloride and amine and imidazoline salts for e.g. primary, secondary and tertiary amine hydroch rides 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.

It is especially preferred for personal wash systems of the invention to include up to 30% other liquid benefit agents such as non-soap surfactants, skin benefit materials such as moisturisers, emollients, sunscreens, anti ageing compounds are incorporated at any step prior to step of milling. Alternatively certain of these benefit agents are introduced as macro domains during plodding.

Builders

In addition to the essential alkali metal aluminosilicates (zeolites), detergency builders used in the formulation are preferably inorganic and suitable builders include, for example, alkali metal carbonate, sodium tripolyphosphate (STPP), tetrasodium pyrophosphate (TSPP), citrates, sodium nitrilotriacetate (NTA) and combinations of these. Builders are suitable used in an amount ranging from 1 to 30% by wt. Benefit agents:

If the detergent active is soap and compositions are formulated for personal wash other benefit agents may be incorporated. Examples of moisturisers and humectants include polyols, glyceral, cetyl alcohol, carbopol, ethoxylated caster oil, paraffin oils, lanolin and its derivatives. Silicone compounds such as silicone surfactants like DC3225C (Dow Corning) and/or silicon emollients, silicone oil (DC-200 Ex-Dow Corning) may also be included. Sub-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. Water soluble glycols such as propylene glycol, ethylene glycol, glycerol, may be employed at levels up to 10%.

Inorganic particulates

Inorganic particulate phase is not an essential ingredient of the formulation but may be incorporated especially for hard surface cleaning compositions. Preferably, the particulate phase comprises a particulate structurant and/or abrasive, which is insoluble in water. In the alternative, the abrasive may be soluble and present in such excess to any water present in the composition that the solubility of the abrasive in the aqueous phase is exceeded and consequently solid abrasive exists in the composition.

Suitable inorganic particulates can be selected from, particulate zeolites, calcites, clays (such as china clay), dolomites, feldspars, silicas, silicates, other carbonates, bicarbonates, sulphates and polymeric materials such as polyethylene.

The most preferred inorganic particulates are calcium carbonate (as Calcite), china clay, mixtures of calcium and magnesium carbonates (as dolomite), sodium hydrogen carbonate, borax, sodium/potassium, sulphate, zeolite, feldspars, talc, koalin and silica.

Calcite, talc, kaolin, feldspar and dolomite and mixtures thereof are particularly preferred due to their low cost and colour.

Other additives

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

Minor additives

Conventional ingredients preferably selected from enzymes, antiredeposition agents, fluorescers, colour, preservatives and perfumes, also bleaches, bleach precursors, bleach stabilisers, sequestrants, soil release agents (usually polymers) and other polymers may optionally be incorporated up to 10 wt%.

EXAMPLES

The invention will now be explained in more detail by way of the following examples.

Different formulations as described in Table 1 was prepared and analysed for hardness, % moisture and bar density. Process for preparing the detergent bar

a. Conventional Process

A batch of 6-kg detergent bar was prepared by taking 1.2kg of linear alkyl benzene sulphonic acid in a sigma mixer and neutralising it with 250g of sodium carbonate, followed by the addition of 360g (formulation) sodium carbonate, 300g of (50%) aluminium sulphate and 22g of (40%) silicate was added to generate aluminosilicate. Other ingredients such as 720g of STPP builder, approximately 3kg of fillers, water and minor ingredients were then added. These were thoroughly mixed and plodded in a conventional manner (Example 1). The moisture of the plodded bar is ~6%. In Example 2, the same procedure was followed by the water content was raised to 9% by reducing the amount of fillers by 180g, i.e. 3%. In Examples 5 borax was added (as a powder) and in Example 6 Poly(vinyl alcohol) {88% poly(vinyl alcohol) + 12% poly (vinyl acetate) and degree of polymerisation ~ 2000} was added.

b. In situ generation of alumina and alumina Na citrate

LAS acid was taken in the mixer and was neutralised with sodium aluminate instead of sodium carbonate (Example 3)

Example 4: In the sigma mixer, Citric acid is first neutralised using sodium aluminate, the sodium aluminate required for LAS neutralisation is added, followed by the addition of LAS acid. The rest of the procedure was as described for Example 1. c. Process according to the invention

In Example 7 a mixture of boron poly vinyl alcohol was introduced into the detergent active formed by neutralisation of LAS acid with sodium carbonate. In Example 8, amorphous alumina-carboxylate and detergent active was generated by a reaction of a mixture of LAS and citric acid with sodium aluminate (as in the case of Example 4) with 44% solid content having an AI2O3 to Na2θ ratio of 1.1 by weight in a sigma mixer. Boron-polyvinyl alcohol mixture was added to this and the bars were processed otherwise as described in Example 1.

The samples were tested for various physical and in-use properties by the following procedure.

Bar hardness

Bar hardness for a given moisture level is a direct indicator of how well the bar is structured. A penetrometer was used to get an estimate of the hardness of the detergent bars, based on the depth of penetration of a needle. Higher the penetration, less the hardness and the yield stress and vice-versa. The penetrometer used as a SUR type PNR 10 (Sommer und Runge of Berlin). Measurements are made by allowing a needle with a cone angle of 9° degrees to fall under a set weight of 50gms for 20 seconds on top of a flat surface of the bar. The depth of penetration is reported in mm.

Density of the bar

The density of the bar is measured by the standard method and calculated using the formula Density (grams/cm ) Weight of bar (grams)

Volume in cm³

Table 1

above. The data presented in Table 1 show that incorporation of boron hydroxy polymer gel helps in structuring water significantly and also reduces the density of the bar but the effect of the structuring system is superior when the aluminium is used to generate the detergent active. Without the boron hydroxy polymer gel if the level of water is increased (Example 2, 5 & 6), the bars become soft and are not processable.

d. Effect of boron-galactomannan polymer (guar gum) on bar structuring

Examples 9 and 10 demonstrate the increased water structuring and density reduction that could be obtained by increasing the level of boron - poly vinyl alcohol mixture. In examples 11 and 12 guar gum, a naturally occurring polymer with reactive hydroxyl groups, molecular weight - 200,000 (as a powder) and borax (powder) were added to the detergent active formed by neutralisation of LAS acid by sodium carbonate. These were processed as per the description above but in the absence of any generated sodium citrate or alumina. The bar hardness and density were measured as per the procedure described.

Table 2

The data presented in Table 2 show that incorporation of boron-poly vinyl alcohol and boron-guar gum can structure significant levels of water and also reduce the bar density.

Claims

1. A process for the preparation of a detergent bar, the process comprising the steps of

(b) converting the admixed components resulting from (a), into a detergent bar.

2. A process for the preparation of low density bars with high water content, the process comprising the steps of:

(a) reacting a precursor of a detergent active with an alkaline material;

(c) generating in situ sodium aluminosilicate by allowing a source of monomeric aluminium to condense with a silicate anion;

(d) adding if desired, other detergent actives, builders, fillers and minor ingredients; and (e) converting the product into bars by a conventional method, the ingredients being incorporated in such amounts as to provide a bar composition comprising:

from 5% to 70%, preferably from 15% to 30%> by weight of detergent active;

from 1 % to 15%), preferably from 2% to 10% by weight of aluminosilicate;

from 5% to 40%, preferably from 6% to 25% by weight water;

from 0% to 30%, preferably from 5% to 20% by weight detergent builder; and

from 0% to 60%, preferably from 10% to 40% by weight inorganic particulates.

3. A process according to either preceding claim, wherein the alkaline material contains aluminium.

4. A process according to any preceding claim, wherein the alkaline material is sodium aluminate.

5. A process according to claim 4, wherein the sodium aluminate has a solids content of 20% to 55% by weight and wherein the weight ratio of

AI₂O₃ to Na₂O is from 0.5 to 1.55.

6. A process according to any preceding claim, wherein the acid precursor is selected from anionic surfactant acids, fatty acids and mixtures thereof.

7. A process according to any preceding claim, wherein the acid precursor and alkaline material are reacted in the presence of a non- fatty acid carboxylic acid.

8. A process according to claim 7, wherein the non-fatty acid carboxylic acid is selected from C1-C5, monocarboxylic acids and their polymers, aliphatic or aromatic di-, tri- or polycarboxylic acids, hydroxy- and amino-carboxylic acids and mixtures thereof.

9. A process according to claim 7 or claim 8, wherein the weight ratio of the acid precursor to the carboxylic acid is from 1 :1 to 60:1.

10. A process according to any preceding claim, wherein the hydroxy and/or amino group containing polymer is selected from poly(vinylalcohol), poly(vinylacetate) and other polymers having reactive hydroxy or amino electron donating groups.

11. A process according to any preceding claim, wherein the hydroxy and/or amino group containing polymer has a degree of polymerisation of from 100 to 5,000.

12. A process according to any preceding claim, wherein the boron containing compound is selected from borax, boric acid and mixtures thereof.

13. A process according to any preceding claim, wherein the reaction between the boron containing compound and the hydroxy and/or amino group containing polymer is effected in the presence of a cross-linking agent.

14. A process according to any preceding claim, wherein the mole ratio of the boron containing compound to the hydroxy and/or amino containing polymer is from 0.1 to 15.

15. A process according to any preceding claim, wherein the generating reactants comprise aluminium sulphate and sodium silicate.

16. A detergent bar composition which comprises:-

from 5% to 70%, preferably from 15% to 30% by weight of detergent active;

from 1 % to 15%, preferably from 2% to 10% by weight of aluminosilicate;

from 5% to 40%, preferably from 6% to 25% by weight water;

from 0% to 30%, preferably from 5% to 20% by weight detergent builder; and

from 0% to 60%, preferably from 10% to 40% by weight inorganic particulates.