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ABRASIVE CLEANING COMPOSITIONTechnical FieldThe invention relates to non-liquid, abrasive, compositions containing a particulate abrasive which are suited to the cleaning of hard surfaces.

Backaround to the InventionHard surface cleaners containing abrasive particles are well known. Typical compositions comprise one or more surfactants in solution and a plurality of abrasive particles dispersed therein. Surfactants employed in liquid abrasive cleaners have included, alkyl benzene sulphonates, alcohol sulphates, alcohol ethoxylates, alkyl amido ethoxylates, fatty acid soaps and secondary alkyl sulphonates. Combinations of these surfactants, together with electrolytes are generally used to form a suspending system as is well known in the art.

Solvents are well known components of non-abrasive cleaning compositions. Typical solvents used in cleaning compositions include, alcohols (such as ethanol), ethers (such as Butyl Cellosolve), paraffins (such as Isopar L), esters and terpenes (such as d-limonene). Another known class of solvents are the alkanolamines. EP503219A (P & G) relates to a cleaning composition containing 0.1 - 10% of an alkanolamine.

Non-liquid abrasive compositions are also known. These take the form of pastes, gels and powders. These may contain surfactants and may contain relatively low levels of water.

Typical abrasives used in these compositions include, calcites and dolomites.

Brief Descrittion of the InventionWe have now determined that improved non-liquid abrasive cleaners can be formulated with significant levels of a C2-C6 alkanolamine and an electrolyte base other than alkanolamine. The presence of alkanolamines is desirable as at elevated pH due to the base the alkanolamine can act as both a solvent and as a further base to assist in the removal of difficult soils. Thus the present invention provides a abrasive cleaner which effectively cleans and is stable on storage.

Detailed Descrintion of the InventionThe present invention provides a non-liquid abrasive cleaning composition which comprises a) 50-99.5%wt of one or more particulate abrasives, b) 0.5-15%wt of a C2-C6 alkanolamine, c) at least 0.1%wt of an electrolyte base other than alkanolamine, d) optionally 0.1-20%wt of one or more surfactants, and, e) optionally, 0.1-20%wt of a solvent other than water or alkanolamine It is believed that, in the presence of water, i.e. during use, the combination of the base and the alkanolamine improves cleaning.

The invention also extends to a method of light duty cleaning (i.e. dishwashing) which comprises the step of treating the articles being cleaned with a composition as disclosed herein.

In the context of the present invention non-liquid abrasive relates to products in the form of a paste, gel or powder.

AbrasivesA particulate abrasive phase is an essential ingredient of compositions according to the present invention.

Preferably, the particulate phase comprises a particulate 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 abrasives can be selected from, particulate zeolites, calcites, dolomites, feldspar, silicas, silicates, other carbonates, aluminas, bicarbonates, borates, sulphates, and, polymeric materials such as polyethylene.

Preferred abrasives for use in general purpose compositions have a Moh hardness of 2-6 although higher hardness abrasives can be employed for specialist applications.

Preferred average (weight average) particle sizes for the abrasive fall in the range 0.5-400 microns, with values of around 10-200 microns being preferred. In this range an acceptable compromise between good cleaning behaviour and low substrate damage is achieved.

Preferred levels of abrasive range from 60-95wt% on product, preferably in the range 65-90wt. The physical form of the product will be influenced by the level of abrasive present.

In general compositions with higher levels of abrasive will be powders whereas those with lower levels will be pastes.

Exactly where a particular abrasive product changes from powder to paste with a particular abrasive present at decreasing levels is influenced by the other components present. From the preferred embodiments of the invention described below it can be seen that the compositions become a paste if the level of abrasive falls below 80-90%wt.

The physical stability of a paste may be improved by having a high level of abrasive present. In this instance a high level of abrasive is greater than 80% by weight of the total composition.

The most preferred abrasives are calcium carbonate (as calcite), mixtures of calcium and magnesium carbonates (as dolomite), sodium hydrogen carbonate, potassium sulphate, zeolite, alumina, hydrated alumina, feldspar, talc and silica.

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

AlkanolaminesAlkanolamines for use in the compositions of the present invention can be mono- or poly-functional as regards the amine and hydroxy moieties. Preferred alkanolamines are generally of the formulation H2 N-R1-OH where Ri is a linear or branched alkyl chain having 2-6 carbons. Preferred alkanolamines include: 2-amino-2-methyl-l-propanol, mono- di- and tri- ethanolamine, mono-, di- and tri -isopropanolamine, dimethyl-, diethyl or dibutyl ethanolamine, and mixtures thereof.

It is envisaged that cyclic alkanolamines such as morpholine can also be employed.

Particularly suitable alkanolamines include: 2-amino-2methyl-l-propanol, mono-ethanolamine and di-ethanolamine.

These materials are believed to give improved cleaning on tough or aged soils. Of these materials 2-amino-2-methyl-lpropanol (AMP) is particularly preferred.

Typical levels of alkanolamine in the compositions of the invention range from l-10%wt. Higher levels are less desirable due to cost and as these may attack certain plastics materials. It is particularly preferred to use 2amino-2-methyl-1-propanol at a level of 2-6%wt.

Electrolvte baseSuitable electrolyte bases include soluble carbonates and bicarbonates, although the use of hydroxides and other alkaline salts is not excluded. Alkali metal carbonates are particularly preferred, with potassium carbonate being the most preferred.

Typical levels of electrolytes range from 0.5-5%wt, with 12.5%wt being particularly preferred. The level of the electrolyte should be such that in use the pH of the composition is raised above the pKa of the alkanolamine, and preferably to a pH at least one unit above the pKa of the alkanolamine. Whether the pH reaches the desired level can be tested by forming a 50%wt slurry of the composition with water and measuring the pH.

Electrolyte can serve a further function in compositions which contain relatively low levels of abrasive, in particular when the abrasive level is below 75% on product and/or where the product is in the form of a paste. It is believed that as a abrasive level in the compositions is lowered the compositions become progressively more unstable and the tendency for the compositions to separate into two phases increases. This can be overcome by the use of potassium carbonate as the electrolyte and the addition of water to the composition.

In compositions which contain potassium carbonate and water it is preferable that the abrasive material is feldspar. It is believed that ion-exchange between the potassium carbonate and the other preferred abrasive materials (particularly dolomite) leads to a progressive buffering of the composition which lowers the pH and eventually reduces the effectiveness of the composition.

SurfactantsThe composition according to the invention will preferably comprise detergent actives which are generally chosen from both anionic and nonionic detergent actives. Surfactant is not a necessary component of the compositions, but provides some foaming which is generally expected by the user and can provide an additional cleaning benefit on certain soils. In some circumstances the presence of surfactant may assist in structuring the product.

Suitable anionic detergent active compounds are watersoluble 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 sulphur 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 and potassium secondary alkanesulphonates; 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;STDC0385 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 olefinsulphonates and higher alkyl sulphates, and the higher fatty acid monoglyceride sulphates. The most preferred anionic detergent active compounds are higher alkyl aromatic sulphonates such as higher alkyl benzene sulphonates containing from 6 to 20 carbon atoms in the alkyl group in a straight or branched chain, particular examples of which are sodium salts of higher alkyl benzene sulphonates or of higher-alkyl toluene, xylene or phenol sulphonates, alkyl naphthalene sulphonates, ammonium diamyl naphthalene sulphonate, and sodium dinonyl naphthalene sulphonate.

The amount of synthetic anionic detergent active to be employed in the detergent composition of this invention will generally be up to 20%, and most preferably from 2 to 15% by weight.

Suitable nonionic detergent active compounds can be broadly described as compounds produced by the condensation of alkylene oxide groups, which are hydrophillic in nature, with an organic hydrophobic compound which may be aliphatic or alkyl aromatic in nature. The length of the hydrophillic 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 hydrophillic 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 condensates containing from 40 to 80% of polyoxyethylene radicals by weight and having a molecular weight of from 5,000 to 11,000;STDC0777 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 R3P0, 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 R2S0 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.

The amount of nonionic detergent active to be employed in the detergent composition of the invention will generally be from 0.5 to 15%wt, preferably from 5 to 10% by weight.

It is also possible optionally to include amphoteric, cationic or zwitterionic detergent actives in the compositions according to the invention.

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 3dodecylamino-propionate, sodium 3-dodecylaminopropane sulphonate and sodium N-2-hydroxydodecyl-N-methyltaurate.

Suitable cat ironic detergent-active compounds are quaternary ammonium salts having an aliphatic radical of from 8 to 18 carbon atoms, for instance cetyltrimethyl ammonium bromide.

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 watersolubilising group, for instance 3-(N,N-dimethyl-Nhexadecylammonium)propane-l-sulphonate betaine, 3 (dodecylmethyl sulphonium) propane-l-sulphonate betaine and 3-(cetylmethylphosphonium) ethane sulphonate betaine.

Further examples of suitable detergent-active compounds are compounds commonly used as surface-active agents given in the well-known textbooks Surface Active Agents", Volume I by Schwartz and Perry and "Surface Active Agents andDetergents", Volume II by Schwartz, Perry and Berch.

The total amount of detergent active compound to be employed in the detergent composition of the invention will generally be from 1.5 to 20%, preferably from 2 to 15% by weight.

SolventsSolvents other than AMP can be present in the compositions of the invention and their presence is preferred for this reason.

Suitable solvents include saturated and unsaturated, linear or branched hydrocarbons, and/or materials of the general formula: Rl-O- (EO)m- (P )n-R2' wherein R1 and R2 are independently C1-7 alkyl or H, but not both hydrogen, m and n are independently 0-5.

Preferred solvents are selected from the group comprising CloHl6 terpenes, C1O-Cl6 straight chain paraffins, and the glycol ethers.

Suitable glycol ethers include di-ethylene glycol mono nbutyl ether, mono-ethylene glycol mono n-butyl ether, propylene glycol n-butyl ether and mixtures thereof.

Suitable terpenes include d-limonene. Preferred paraffins include the material available in the marketplace as 'Shellsol-T'.

Typical levels of solvent range from 1-15%wt. It is particularly preferred to use terpines at levels l-3%wt.

Some of these terpene materials, such as limonene, have the further advantage that the exhibit insect-repellency. We have determined that the terpene materials give better performance at in use pHis below 11. The straight chain paraffins can be used at higher levels than the terpenes as these materials are less aggressive to plastics. The paraffins are believed to give better performance at in use pH's above 11.

The glycol ethers are preferred over the other solvents, at typical levels of 5-10%wt on product with di-ethylene glycol mono n-butyl ether being particularly preferred.

It is preferred that the ratio of the alkanolamine to the solvent falls in the range 3:1-1:3, with ratios of 1:1 to 1:3 being particularly preferred.

Advantageously, a portion of the solvent can be introduced as a perfume component, although the levels of solvent required will generally require the addition of higher levels of this component that would normally be present as a perfume ingredient in cleaning compositions. Preferably the terpenes are used in this manner as selected terpenes, such as limonene, have a pleasant citrus smell, whereas paraffins and glycol ethers are generally odourless.

Rheolov and Structuring AgentsAs described above the compositions of the invention can be pastes, gels or powders. Suitable rheological control agents can be present especially when the compositions contain significant amounts of water or low viscosity surfactants. These control agents include fumed silicas and clays.

We have determined that 1-2%wt of a fumed silica is sufficient to stabilize a paste. Aerosil 380 (TM) is a suitable structuring agent.

We have also determined that the addition of 1-8% water can also be sufficient to stabilise compositions which are prone to separation.

Compositions which contain mixed surfactant systems are also believed to be stable against phase separation. We have determined that a composition which contains both an ethoxylated alcohol nonionic surfactant and a nonionic alkyl polyglucoside (APG) surfactant is stable against phase separation.

The compositions according to the invention may optionally contain polymeric structuring agents to aid in providing appropriate rheological properties and in enhancing their distribution and adherence of the composition to the hard surface to be cleaned.

Preferred structuring agents include polysaccharides, such as sodium carboxymethyl cellulose and other chemically modified cellulose materials, xanthan gum and other nonflocculating structuring agents such as Biopolymer PS87 referred to in US Patent No. 4 329 448. Certain polymers such as a polymer of acrylic acid cross-linked with a poly R functional agent, for example CARBOPOL , can also be used as structuring agents. The amount of such structuring agents, when employed, to be used in compositions according to the invention can be as little as 0.001%, preferably at least 0.01% by weight of the composition.

In general, the composition of the invention can optionally comprise from 0.1-1% of polymer.

Optional IngredientsThe composition according to the invention can contain other ingredients which aid in their cleaning performance. For example, the composition can contain detergent builders other than the special water-soluble salts, as defined herein, such as nitrilotriacetates, polycarboxylates, citrates, dicarboxylic acids, water-soluble phosphates especially polyphosphates, mixtures of ortho- and pyrophosphate, zeolites and mixtures thereof. Such builders can additionally function as abrasives if present in an amount in excess of their solubility in water. In general, the builder, other than the special water-soluble salts when employed, preferably will form from 0.1 to 25% by weight of the composition.

Metal ion sequestrants such as ethylenediaminetetraacetates, amino-polyphosphonates (DEQUEST ) and phosphates and a wide variety of other poly-functional organic acids and salts, can also optionally be employed provided they are compatible with the abrasive material.

Compositions according to the invention can also contain, in addition to the ingredients already mentioned, various other optional ingredients such as colourants, whiteners, optical brighteners, soil suspending agents, detersive enzymes, compatible bleaching agents (particularly hypohalites), bactericides, and preservatives (for example 1,2, benzisothiazolin-3-one).

Preferred Comcositions Preferred compositions according to the present invention comprise: a) 70-90%wt, preferably 75-80%wt of one or more particulate abrasives selected from the group comprising: calcium carbonate, magnesium carbonates, feldspar and mixtures thereof, b) l-6%wt, preferably 2-6%wt of an alkanolamine selected from the group comprising: 2-amino-2-methyl-l-propanol, mono- di- and tri- ethanolamine, mono, di- and tri isopropanolamine, dimethyl-, diethyl- or dibutyl ethanolamine, and mixtures thereof, c) 0.5-5%wt, preferably 1-5%wt of an alkali metal carbonate or bicarbonate electrolyte, d) 2-10%wt, preferably 5-10%wt of one or more surfactants, and, e) 2-10%wt, preferably 5-15%wt of a glycol ether solvent.

In order that the invention may be further understood it will be described hereinafter with reference to the following non-limiting examples:EXAMPLESIn the following Examples:Imbentin 91 3.5 OFA is a fatty alcohol having an average carbon chain length of Cg-Cll and an average degree of ethoxylation at 5 mol EO (ex Libran Chemicals Ltd).

Glucopan 600 CS/UP HH is an alkyl polyglycoside with an average carbon chain length of Cl2-Cl4 (ex Henkel).

AMP is 2-amino 2-methyl-l-propanol.

Dolomite is a magnesium carbonate/calcium carbonate mix.

Example 1: basic formulations.

Compositions P1-P3 were prepared as in Table 1 below.

Table 1EMI15.1 <tb> Component <SEP> % <SEP> P1 <SEP> P2 <SEP> P3<tb> Dolomite <SEP> (abrasive) <SEP> 90 <SEP> 75 <SEP> 70<tb> Imbentin <SEP> 91 <SEP> 3.5 <SEP> OFA <SEP> (TM) <SEP> 4.3 <SEP> 10.7 <SEP> 5.27<tb> Glucopon <SEP> 600 <SEP> CS/UP <SEP> HH <SEP> (TM) <SEP> - <SEP> - <SEP> 5.27<tb> AMP <SEP> 1.7 <SEP> 4.3 <SEP> 4.22<tb> Butyl <SEP> Digol <SEP> 3.4 <SEP> 8.6 <SEP> 8.43<tb> Potassium <SEP> Carbonate <SEP> anhydrous <SEP> 0.6 <SEP> 1.4 <SEP> 1.32<tb> Water <SEP> - <SEP> ? <SEP> <SEP> to <SEP> 100%<tb> Sample preparation entailed pre-mixing the liquid ingredients, then adding the K2CO3 to the dolomite followed by the pre-mixed liquid.

Example P1 was a powder P1 showed no separation of ingredients. Example P3 was a paste, Example P2 was also a paste.

From the results given above it can be seen that stable compositions can be made with both single and mixed surfactant systems.

Example 2: use of fumed silica.

The following formulations were made up: Table 2EMI16.1 <tb> Component <SEP> % <SEP> P2 <SEP> ] <SEP> P2a <SEP> P2b <SEP> P2c <SEP> <tb> Dolomite <SEP> 75 <SEP> 75 <SEP> 75 <SEP> 75<tb> Imbentin <SEP> (TM) <SEP> 10.8 <SEP> 10.54 <SEP> 10.32 <SEP> 9.89<tb> Butyl <SEP> Digol <SEP> 8.6 <SEP> 8.43 <SEP> 8.26 <SEP> 7.91<tb> AMP <SEP> 4.3 <SEP> 4.21 <SEP> 4.13 <SEP> 3.96<tb> K2CO3 <SEP> 1.3 <SEP> 1.32 <SEP> 1.29 <SEP> 1.24<tb> Aerosil <SEP> 380 <SEP> (TM) <SEP> - <SEP> <SEP> 0.5 <SEP> 1.0 <SEP> 2.0<tb> fumed <SEP> silica<tb> PH <SEP> after <SEP> 24 <SEP> hours <SEP> of <SEP> 11.9 <SEP> - <SEP> <SEP> 11.4 <SEP> 11.2<tb> 50% <SEP> slurry<tb> The formulations were made up as described earlier, then theAerosil 380 was carefully stirred in.

The physical appearance of the formulations containing fumed silica remained unchanged over several months. The formulation without the fumed silica (Aerosil 380 (tm)) was not as stable. From these results it can be seen that the fumed silica is an effective stabiliser.

Example 3: Use water to achieve stabilityA sample of P2 was taken and a small amount of water added.

The water caused an increase in apparent viscosity of the sample, and no separation was evident after about 60 hours.

Samples of example P2 were taken and different amounts of water added. The appearance of the samples was noted after 24 hours, and the stable samples were monitored over several weeks. Results are given in table 3 below: Table 3EMI17.1 <tb> % <SEP> water <SEP> added <SEP> to <SEP> P2 <SEP> After <SEP> 24 <SEP> hours<tb> <SEP> 0 <SEP> <SEP> Clear <SEP> layer <SEP> separation <SEP> (CLS)<tb> <SEP> 1.96 <SEP> No <SEP> CLS<tb> <SEP> 3.85 <SEP> No <SEP> CLS<tb> <SEP> 5.66 <SEP> No <SEP> CLS<tb> <SEP> 7.41 <SEP> Shiny <SEP> surface,STDC0368 <SEP> but <SEP> no <SEP> CLS<tb> <SEP> 9.09 <SEP> CLS<tb> 10.71 <SEP> CLS<tb> CLS = Clear layer separationThe samples showing no clear layer separation after 24 hours remained stable for the duration of the experiment (about 2 months). The experiment was repeated successfully withDobanol 91-8 (TM) replacing the Imbentin 91 3.5.

Example 4: Preferred ElectrolyteThe preferred electrolyte is a soluble carbonate. To illustrate this two further samples were made up replacing potassium carbonate on a mole for mole basis with either potassium sulphate (P2i) or potassium iodide (P2j). Each sample was then split into 50g samples, different amounts of water added, and the stability monitored after 24 hours.

Table 4EMI18.1 <tb> Sample <SEP> Appearance <SEP> after <SEP> 24 <SEP> hours<tb> 50g <SEP> P2 <SEP> + <SEP> 0.5g <SEP> water <SEP> Thick. <SEP> Shiny <SEP> surface.<tb>

<SEP> No <SEP> CLS<tb> 50g <SEP> P2 <SEP> + <SEP> 1.0g <SEP> water <SEP> Thick. <SEP> Holds <SEP> shape. <SEP> No<tb> <SEP> CLS<tb> 50g <SEP> P2 <SEP> + <SEP> 2.0g <SEP> water <SEP> Thick. <SEP> Holds <SEP> shape. <SEP> No<tb> <SEP> CLS<tb> 50g <SEP> P2i <SEP> (K2S04) <SEP> Spreads. <SEP> CLS<tb> 50g <SEP> P2i <SEP> + <SEP> 0.5g <SEP> water <SEP> Spreads. <SEP> CLS<tb> 50g <SEP> P2i <SEP> + <SEP> l.0g <SEP> water <SEP> Spreads. <SEP> CLS<tb> 50g <SEP> P2i <SEP> + <SEP> 2.0g <SEP> water <SEP> Spreads. <SEP> CLS<tb> 50g <SEP> P2j <SEP> (KI) <SEP> Spreads. <SEP> CLS<tb> 50g <SEP> P2j <SEP> + <SEP> 0.5g <SEP> water <SEP> Spreads. <SEP> CLS<tb> 50g <SEP> P2j <SEP> + <SEP> 1.0g <SEP> water <SEP> Spreads.STDC0396 <SEP> CLS<tb> 50g <SEP> P2j <SEP> + <SEP> 2.0g <SEP> water <SEP> Spreads. <SEP> CLS<tb> Potassium carbonate is a hydratable salt. Potassium sulphate and potassium iodide are non-hydratable. The experiment was repeated replacing the anhydrous potassium carbonate with other anhydrous but hydratable salts, namely sodium carbonate (P2k) and sodium sulphate (P21).

Table 5EMI19.1 <tb> <SEP> Sample <SEP> Appearance <SEP> after <SEP> 24 <SEP> hours<tb> 50g <SEP> P2k <SEP> (Na2CO3) <SEP> Spreads. <SEP> CLS<tb> 50g <SEP> P2k <SEP> + <SEP> 1.0g <SEP> water <SEP> Reduced <SEP> CLS<tb> 50g <SEP> P2k <SEP> + <SEP> 2.0g <SEP> water <SEP> Reduced <SEP> CLS<tb> 50g <SEP> P21 <SEP> (Na2SO4) <SEP> Spreads. <SEP> CLS<tb> 50g <SEP> P21 <SEP> + <SEP> 1.0g <SEP> water <SEP> Spreads. <SEP> CLS<tb> 50g <SEP> P21 <SEP> + <SEP> 2.0g <SEP> water <SEP> Spreads. <SEP> CLS<tb> The sodium carbonate samples with water added showed reduction in the amount of clear layer separation compared to the original sample, but were not as thick as the potassium carbonate. The physical stability of the sodium sulphate sample was not improved by water addition.

The above experiment was repeated using hydrated potassium carbonate (K2CO.l1/H2O. Sample P2m) rather than the anhydrous salt.

Table 6EMI19.2 <tb> Sample <SEP> Appearance <SEP> after <SEP> 24<tb> <SEP> hours<tb> 50g <SEP> P2m <SEP> (K2CO3.11/2H2O) <SEP> Spreads. <SEP> CLS<tb> 50g <SEP> P2m <SEP> + <SEP> 1.0g <SEP> water <SEP> Thick. <SEP> Holds <SEP> shape. <SEP> No<tb> <SEP> CLS<tb> 50g <SEP> P2m <SEP> + <SEP> 2.0g <SEP> water <SEP> Thick. <SEP> Holds <SEP> shape. <SEP> No<tb> <SEP> CLS<tb> These results show that the potassium carbonate can be used either in the anhydrous or the hydrated form. It should however be noted that use of the hydrated salt does not negate the need for water to be added to thicken the sample when low levels of carbonate are used.STDC0304Example 5: Use of different abrasivesThe pH of 50% slurries of Example P2 and with 2% water was measured initially, and then over a couple of weeks, the slurries being made fresh each time the pH was measured. It was determined that the pH of the water containing samples drops over a couple of weeks.

The abrasive of P2 was changed to feldspar (potassium aluminosilicate). 2% water was added to one sample and the pH was monitored as above. Initially the pH of both samples was 11.9. After 10 days the pH of the water free sample was 11.7, whereas the sample with water was 11.8. Thus no pH drop occurred.

Example

Table 7EMI21.1 <tb> Example <SEP> P20 <SEP> P2p <SEP> P2q<tb> Imbentin <SEP> 91 <SEP> 35 <SEP> 10 <SEP> - <SEP> <tb> Butyl <SEP> Digol <SEP> 8 <SEP> 8 <SEP> 8<tb> AMP <SEP> 4 <SEP> 4 <SEP> 4<tb> K2CO3 <SEP> (anh) <SEP> 1.25 <SEP> 1.25 <SEP> 1.25<tb> Dolomite <SEP> 70 <SEP> 70 <SEP> 70<tb> AOS <SEP> 10 <SEP> <tb> LAS <SEP> - <SEP> <SEP> 10<tb> Water <SEP> - <SEP> to <SEP> 10.0 <SEP> where AOS is Alkyl Olefin Sulphonate LAS is Sodium Alkyl Benzene SulphonateFor foaming, samples to be tested were diluted to 0.04% active with a 1:4 mixture of Prenton water:STDC0380demineralised water, giving a final water hardness of -5"FH. The diluted samples were thermostatted at 45 C. 100ml of the sample was put in the plunger cylinder, and 0.2ml aliquots of the standard soil added until the foam died. The number of aliquots required to just 'kill' the foam was determined.

Each sample was tested four times, and the mean and standard deviation calculated.

Table 8EMI22.1 <tb> Sample <SEP> Mean <SEP> no. <SEP> of <SEP> Standard<tb> <SEP> aliquots <SEP> of <SEP> Deviation<tb> <SEP> soil<tb> P2 <SEP> 8 <SEP> 0.8<tb> P3 <SEP> 20.75 <SEP> 0.5<tb> Vim <SEP> Ultra <SEP> Powder <SEP> 14.25 <SEP> 1.0<tb> Vim <SEP> Ultra <SEP> Paste <SEP> 17.25 <SEP> 1.0<tb> P2o <SEP> (Imbentin) <SEP> 8.75 <SEP> 1.0<tb> P2p <SEP> (AOS) <SEP> 18.25 <SEP> 1.3<tb> P2q <SEP> (LAS) <SEP> 23.5 <SEP> 1.7<tb>