WO2001077273A1

WO2001077273A1 - Solid dispersible abrasive compositions

Info

Publication number: WO2001077273A1
Application number: PCT/EP2001/002763
Authority: WO
Inventors: Stephen Briggs; Richard John Curtis; Terry Instone; Steven James Kynaston; Janette Perry
Original assignee: Hindustan Lever Ltd; Unilever NV
Current assignee: Hindustan Unilever Ltd; Unilever NV
Priority date: 2000-04-05
Filing date: 2001-03-09
Publication date: 2001-10-18
Anticipated expiration: 2002-10-05
Also published as: RU2002129360A; CN1422328A; AU2001262090A1; MXPA02009578A; HUP0300292A3; ZA200206780B; RU2256699C2; AR027766A1; HUP0300292A2; BR0109752A; CN1218026C; PL357997A1

Abstract

The invention provides dry compositions comprising a solid abrasive (preferably at least 65 %) and a suspending system (preferably at least 0.1 %) suitable to obtain a stable suspension on mixing with a liquid medium. Suitable suspending systems are based on a surfactants or surfactant mixtures which are able to form a lamellar micelle phase after mixing with the liquid medium or on polymeric thickening systems. The preferred liquid medium is water. The dry abrasive compositions are free flowing and easily dispersible in water by the consumer to obtain a ready-to-use liquid abrasive cleaner.

Description

SOLID DISPERSABLE ABRASIVE COMPOSITIONS

Field of the invention

The invention relates to solid compositions containing an abrasive and suitable to be dispersed in water to obtain a liquid abrasive cleaning composition for cleaning hard surfaces.

Background of the invention

Liquid abrasive cleaning compositions for hard surfacs are well known in the art and typically comprise a combination of detergent surfactants, particularly anionic and nonionic surfactants, which together form a lamellar micelle phase and thereby cause thickening of the liquid. The lamellar phase acts as a suspending system to keep the solid abrasive in a stable suspension. Often electrolyte and/or a polymeric thickener is added to further improve the stability of the suspension.

Thus, in WO 91/08283 liquid abrasive cleaning compositions are disclosed comprising 0.02-20% of detergent, 1-70% of particulate abrasive and 0.01-10% of a thickening mixture consisting of a linear non-starch type polymer and a branched starch type polymer (amylopectin) . The non-starch type polymers include various natural gums and synthetic polymers. Partially acetylated xanthan is particularly preferred. In practice the required amounts of thickening mixture are around 3% by weight of the total composition and the examples all specify 1.5% of non-ionic surfactant.

In WO 95/08619 liquid abrasive cleaning compositions are disclosed comprising a cross-linked polyacrylate, either at least one non-ionic surfactant or a combination of an anionic surfactant and a nonionic surfactant, a pH adjusting agent, and a calcium carbonate abrasive. The compositions are said to contain 0.1-2% of polyacrylate, 0.1-10% of nonionic, up to 10% anionic and 5-60% abrasive. In practice, according to the examples they contain 0.25-0.4% polymer, 0.5% or more nonionic and 40% abrasive. The nonionic is required to provide the right viscosity characteristics. Similar compositions are disclosed in EP 649898 with the extra proviso that they contain hypochlorite and that the surfactant is bleach-stable.

In EP-A-0 875 557 an aqueous thickener composition suitable for a variety of end applications is described which comprises 0.04-30% w/w of a mixture of at least two surfactants in a specific ratio and with a difference in HLB of at least 1 unit and 0.01-5% w/w of an associative thickener selected from hydrophobically modified hydroy- ethylcellulose, hydrophobically modified nonionic polyol and hydrophobically modified alkali-soluble emulsion polymer. In practice the amount of associative thickener is 1-2% and the amount of surfactant mixture 1-10%.

Liquid abrasive cleaning compositions for hard surfaces are normally sold in a ready-to-use form which contains 10-50%, in most cases 30-45% solid abrasive. Such compositions cannot be diluted to e.g. 10-20% solid abrasive content without losing their stability leading to sedimentation. Although in the patent literature abrasive contents of up to 70% are quoted, such contents are not normally found in commercial products.

Before liquid abrasive cleaners became popular it was customary, and in some countries it still is, to clean hard surfaces using powdered abrasive compositions. Such compositions consist almost entirely of powdered abrasive, i.e. for 95% or more, with a small amount (<5%) of a foaming surfactant. The compositions are applied directly onto the hard surface to be cleaned and used with a small amount of water, such as present in a wet cloth. The surfactant aids in cleaning by improving the wetting properties of the water/abrasive mix on the surface and further provides a visual cue of cleaning by the foam which is generated. Thus, in PL 153680 solid abrasive cleaning compositions are described containing 45-95% of ground quartz, feldspar or glass, 1.5-23% of synthetic anionic or nonionic surfactants (particularly Na LAS and alkylene oxide copolymer), a chlorine bleach compound, 0.1-50 phosphoric acid/urea complex and 0.1-25% Na sulphate. GB 1,339,274 describes similar compositions additionally comprising a compound which generates heat on admixture with water during the cleaning operation. RU 2106376 describes a powdered abrasive cleaner containing ground quartz and sodium polyacrylate as a surfactant. The product is intended for use as a classic powdered abrasive. JP-A-02029497 describes abrasive cleaners, which can have the form of a powder, or a liquid and which contain hydroxyapatite as abrasive and a surfactant. EP-A-0 821 721 describes ready-to-use abrasive powders containing a mixture of sodium carbonate and bicarbonate as water-soluble abrasive, an anionic detergent and a solid hypochlorite bleach.

The prior art powdered abrasive cleaning compositions cannot be converted into liquid abrasive cleaning compositions by simply adding a suitable amount of water, because the surfactant present in the powder mix is not intended, and would be unable, to form the lamellar micelle phase required to keep the solid abrasive in stable suspension. Thus, the abrasive would separate quickly and settle to the bottom of the container.

Nevertheless it would be useful to have available a dry mix, either in the form of a powder or of granules or another suitable solid form, which acts as an instant liquid abrasive cleaner, i.e. would be converted into a ready and stable liquid abrasive cleaner on addition of a suitable amount of water. Thus, packaging and transportation costs involved in shipping large amounts of water could be saved and storage conditions adversely affecting the stability of a ready-made liquid system could be avoided.

Dry abrasive soap powders are also known for removing tough soil from the skin. Such products are described e.g. in US 4786432 and US 4786369. They consist of abrasive particles coated with an anionic surfactant mostly fatty acid soap. Soap powders generally contain less than about 80% of abrasive and in most cases not more than about 50%. EP-B-0 796 318 describes solid free-flowing preparations intended fror cleaning hands. The compositions are obtained by fluidized bed drying and granulation of a mixture of a detergent paste and an abrasive selected from pumice, wood meal, ground nut shells or vegetable fibres. Such powders are not intended to be mixed with water before use and the soap system used therein does not have any suspending properties for the abrasive.

WO 94/25563 describes tablets, blocks or similarly shaped articles comprising surfactants and optionally abrasives. They are intended to be used in cleaning machinery and are clearly not suitable to be transferred into a stable suspension. It is mentioned herein that the blocks and their use avoid the need for a suspending system.

However, there is no indication that any of the above described solid products could be converted into a stable suspension.

Brief description of the invention

The invention provides dry solid compositions which can be mixed with a liquid medium to provide a stable, ready to use liquid abrasive cleaning composition for hard surfaces. Thus, the dry compositions comprise a solid abrasive and a suspending system which keeps the abrasive in stable suspension after mixing with the liquid medium. The invention also provides a process for preparing liquid abrasive cleaning compositions comprising the step of mixing a dry composition, which comprises a solid abrasive and a suspending system, with a liquid medium, without the need for any further mixing in of additional components.

Furthermore the invention provides liquid abrasive cleaning compositions obtained according to the process described above.

Detailed description of the invention

All percentages given herein are by weight of the total composition unless specified otherwise.

The dry abrasive compositions according to the invention comprise as essential ingredients a solid abrasive as the main component, preferably in an amount of at least 55%, and a suspending system suitable to obtain a stable suspension on mixing with the liquid medium, preferably in an amount of at least 0.1%. Furthermore the compositions comprise as highly desirable but optional component a foaming surfactant, preferably in an amount of at least 0.1%.

The dry compositions are suitable for the consumer to be mixed by him at home with a liquid medium to obtain the ready-to-use liquid abrasive cleaner. Alternatively, the dry compositions can be shipped to a factory where simple mixing equipment is sufficient to convert the dry composition in a ready-to-use liquid abrasive composition ready for packaging and transport to the consumer.

The liquid medium can be any liquid, which is suitable and safe for use by the consumer. Thus, it should be innocuous to health and preferably non-flammable. The obvious choice is water, but some organic solvents or mixtures of such solvents with water can be suitable as well. Preferably, the medium consists for at least 85% of water.

Preferably the amount of abrasive in the dry composition is at least 65%, more preferably at least 70% or even 75%. The abrasive can be any fine particulate solid known in the art for its suitability as an abrasive material. Most of the known materials are insoluble in water, however, suitable materials, which are water-soluble, are known as well. Preferred abrasives have Moh hardness of 6 or below, although higher hardness abrasives can be employed for special applications. Generally, the lower the hardness of the abrasive materials the lesser the surface damage, although a hardness of 1 or more is preferred to give sufficient cleaning capability.

Suitable water-insoluble abrasives can be selected from synthetic as well as naturally occurring materials (minerals) and examples include: zeolites, silica's, silicates, carbonates, alumina and organic polymeric abrasives such as polyethylene, polycarbonate, polyurethane, polystyrene, polypropylene, polyethylene terephthalate, polymethyl- methacrylate and nylon, and mixtures thereof. Preferred abrasives are: calcium carbonate (as calcite) , mixtures of calcium and magnesium carbonates (as dolomite) , zeolite, alumina, hydrated alumina, feldspar, talc and silica. Calcite and dolomite and mixtures thereof with lower amounts of silica, especially amorphous silica, are particularly preferred due to their low cost and good abrasive properties.

Suitable water-soluble abrasives include sodium carbonate, sodium bicarbonate, sodium tripolyphosphate, sodium borate and potassium sulphate. A water-soluble abrasive on mixing with water yields a saturated aqueous solution of the abrasive and a solid phase of undissolved abrasive particles suspended in the aqueous solution. Liquid abrasive cleaning compositions of this kind have been described e.g. in EP-A-0 193 375.

Preferred weight average particle sizes for the abrasives fall in the range 0.5-500 microns, with values of around 10-100 microns being particularly preferred. In this range an acceptable compromise between good cleaning behaviour and low substrate damage is achieved. Nevertheless, for silica to be used in combination with calcite or dolomite an average particle size in the range of 200-500 microns is very suitable as well.

The suspending system may be any suspending system known in the art for suspending abrasive particles in a liquid abrasive cleaner. Satisfactory ready-to-use liquid abrasive cleaners obtained from the dry abrasive compositions according to the invention should have such fluid flow characteristics that they are stable suspensions when not in use, but thin enough to pour the liquid from the container and spread it on the soiled surface without appearing thin and watery. Thus, the type and amount of suspending system is chosen such that the suspension obtained after mixing the dry composition with an equal amount of water has the following flow properties:

r|o is at least 2500 Pa.s σ_c is 2.5-25

T\₂i is at least 0.1 Pa.s

Wherein: ηo is the viscosity at zero shear rate; σ_c is the shear stress at which the viscosity is 0.1. ηo; and η₂ι is the viscosity at a shear rate of 21 s

Preferably η₂ι is 0.3-5.0, more preferably 0.6-1.8, most preferably 1.0-1.5 Pa.s. Measurements made on:

CSL 100 (TA Instruments) with vane and basket measuring system (basket internal diameter 48mm, vane diameter 38mm and height 24.5mm) to measure viscosity from a stress (σ) of 0.01 Pa to the stress required to give a shear rate of 1 s Haake RV20 with M5 measuring head and SV2p measuring geometry to measure viscosity between shear rates of 0.1 and 389 s . All measurements made at 20 °C.

Well known suspending systems comprise a surfactant or mixture of surfactants, preferably in combination with an electrolyte, in such an amount and ratio that the total combination is able to form a lamellar micelle phase. This surfactant, or one or more of these surfactants, may be a foaming surfactant in which case it is superfluous to add an extra optional foaming surfactant in order to get the desired foaming properties. Preferably, the surfactant, or one or more of these surfactants, is (are) anionic. Very suitable suspension systems may be obtained by combining an anionic surfactant with an electrolyte, a nonionic surfactant or a cationic surfactant. Particularly suitable systems comprise an anionic surfactant and a nonionic surfactant, if desired further completed with an electrolyte.

Such suspending systems are preferably comprised in the dry abrasive composition as follows:

• 0.5-30% anionic surfactant, preferably 1.5-25%, more preferably 2.5-20%;

• 0.2-20% nonionic surfactant, preferably 1.0-15%, more preferably 1.5-12%.

Suitable anionic surfactants are water-soluble salts of organic sulphuric acid esters and sulphonic acids, which have in their molecular structure an aliphatic group containing from 8 to 22 carbon atoms. '

Suitable examples thereof are the following water-soluble salts: long chain aliphatic alcohol sulphates, especially those obtained by sulphating the higher alcohols produced by reducing the glycerides of vegetable or animal oils or fats such as tallow or coconut oil; alkylbenzene sulphonates, such as those in which the alkyl group contains from 6 to 20 carbon atoms; - secondary and primary alkanesulphonates; alkyl glyceryl ether sulphates, especially those ethers of the higher alcohols derived from tallow and coconut oil; fatty acid monoglyceride sulphates; ethoxylated fatty alcohol sulphates containing 1-6 EO units in the molecule ethoxylated alkylphenol sulphates containing 1-8 EO units and in which the alkyl radicals contain 4-14 C-atoms the reaction product of fatty acids, e.g. those derived from coconut oil, esterified with isethionic acid and neutralised with sodium hydroxide; and mixtures thereof.

Very suitable water-soluble synthetic anionic surfactant components of a suspending system are: the sodium, potassium and magnesium alkyl-benzenesulphonates, olefinsulphonates, alkyl sulphates, and fatty acid mono-glyceride sulphates. These surfactants also suitably function as foaming surfactants.

In the absence of a source of calcium ions (such as calcite or dolomite) fatty acid soaps are also suitable as anionic surfactant. Even in the presence of Ca ions a small amount of fatty acid (< 4.5%) may still usefully be added to improve stability of the suspension after dilution.

One class of suitable nonionic surfactants 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 attached to any particular hydrophobic group can be readily adjusted to yield a water- soluble compound having the desired balance between hydrophilic and hydrophobic elements. This enables the choice of nonionic surfactants with the right HLB.

Particular examples include: the condensation products of aliphatic alcohols having from 8 to 22 carbon atoms in either straight or branched chain configuration with ethylene oxide, such as coconut alcohol ethylene oxide condensates 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 2 to 25 moles of ethylene oxide per mole of alkylphenol; - condensates of the reaction product of ethylene diamine and propylene oxide with ethylene oxide, the condensates containing from 40 to 80% of ethyleneoxy groups by weight and having a molecular weight of from 5,000 to 11,000.

Other classes of nonionic surfactants are: tertiary amine oxides of general structure RRRN0, where one R is an aliphatic group of 8 to 18 carbon atoms and the other Rs are each alkyl or hydroxyalkyl groups of 1 to 3 carbon atoms, for instance dimethyldodecylamine oxide; - tertiary phosphine oxides of structure RRRP0, where one R is an aliphatic group of 8 to 18 carbon atoms and the other Rs are each alkyl or hydroxyalkyl groups of 1 to 3 carbon atoms, for instance dimethyl-dodecylphosphine oxide; dialkyl sulphoxides of structure RRS0 where one 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; alkyl mercaptans.

Aliphatic alcohol ethylene oxide condensates and amine oxides are particularly suitable components of a suspending system. The amine oxides also suitably function as foaming surfactants .

Other well known suspending systems comprise one or more polymeric thickening agents. The polymers in such systems may be of natural or synthetic origin. Suitable polymers are often of the anionic type. They are available in emulsion and in solid form. Furthermore, they may be hydrophobically modified and/or cross-linked. Such polymers include polycarboxylate type polymers, such as acrylate, methacrylate and maleic anhydride homopolymers and copolymers, and various polysaccharides, such as carboxy-methylcelluloses, hydroxy- ethylcellulose, hydroxypropyl-methylcellulose, carrageen, alginate, tragacanth gum, locust bean gum, guar gum, etc. The polymers should easily dissolve and thicken in cold water without lumping.

Examples of suitable polymers include: ACUSOL HASE and ASE series such as 820, 823 and 842;

POLYGEL/NEUTRAGEL series such as W30, DA, DS, DR and DB;

RHEOVIS series such as CRX

CARBOPOL series such as Aqua 30, ETD 2690, ETD 2691, ETD

2623, EZ-1, EZ-2, EP-1, LNP-3, 663, 664 and 674; PEMULEN Series such as TR1 and TR2;

STRUCTURE 2001, 3001; ALCOGUM SL-70 and SL-78.

ACUSOL is a trademark of Rohm & Haas; CARBOPOL and PEMULEN are trademarks of B F Goodrich; POLYGEL and NEUTRAGEL are trademarks of Sigma 3V; RHEOVIS is a trademark of Ciba Specialties;

STRUCTURE is a trademark of National Starch & Chemical Co.; ALCOGUM is a trademark of Alco.

The amount of polymer suspending system to be used in the dry abrasive composition according to the invention is chosen such that the viscosity of the suspension obtained on dilution with an equal amount of water is within the limits specified above. The amount is at least 0.1% and will generally not exceed 10%.

Also combinations of surfactant and polymer suspending systems may be used. Particularly, the stability of a suspension based on a surfactant suspending system may be further improved by additionally adding a small amount of a thickening polymer to the dry abrasive composition.

The optional foaming surfactants, when not already present in a surfactant suspending system, may be chosen from known foaming anionic, nonionic, cationic, zwitterionic or amphoteric surfactants which do not adversely affect the suspending system.

The pH of the ready to use liquid abrasive cleaner should preferably be between 5 and 14. Improved cleaning properties are obtained when the pH of the cleaner is alkaline, preferably above 9 and more preferably below 12. The dry abrasive composition should, if necessary, contain an additional pH regulating system, such as a suitable base, to bring the pH of the liquid cleaner between the desired limits. Suitable bases are e.g. alkali metal hydroxides or carbonates, ammonium carbonate, organic bases such as triethylamine, amino-methylpropanol (AMP) , aminobutanol, mono- , di- or tri-ethanolamine, monoisopropylamine or aminomethylpropanediol .

The dry abrasive compositions according to the invention may contain optional components which improve their cleaning properties. Examples thereof are solid bleaching agents, particularly halogen bleaching agents. In the latter case the other components of the dry compositions, particularly the surfactants and suspending system should obviously be bleach- stable. Other examples are organic solvents such as hydrocarbons and terpenes, alkanol-amines, (poly) ethylene and (poly)propylene glycols and C1-C6 alkyl or phenyl ethers thereof. The amount of such solvents should be such as to not interfere with the free-flowing properties of the dry composition and therefore generally be below 6% .

Furthermore the dry compositions may contain other optional components well known in the art for liquid abrasive cleaners, such as components :

• to increase their attractiveness to the consumer, such as colorants, optical brighteners and particularly perfumes;

• to prevent microbial contamination or give antimicrobial properties to the product, e.g. preservatives and bactericides; • to increase their handling properties such as: free-flowing agents (layering agents, < 10%) to prevent lumping of the dry composition (examples: Alusil ET, a porous aluminium silicate marketed by J. Crosfield, and Socal P2V, marketed by Solvay) , dispersing agents to improve easy dispersion of the dry composition in water and/or to give the obtained suspension freeze/thaw stability (examples: anionic polymers with a mol . weight < 100,000, STP and/or other organic or inorganic phosphates or phosphonates) , antifoams to prevent excessive foaming (example: fatty acid) .

The free-flowing agents and the dispersing agents are particularly preferred additional components.

The dry compositions according to the invention may have any form, which is suitable for easy dispersion in water, such as powder, granules, prills or even tablets. Powders, granules and prills should preferably be free flowing. Spray-drying, fluid bed drying, granulation and similar processes known in the art are very suitable to obtain products, which are free flowing and easily dispersible without lumping. For granulation the addition of a granulating aid such as a polyethelene glycol with mol. weight of 1500-4000 may be useful.

Tablets may be obtained by compressing a predetermined amount of the afore mentioned products. They may contain a disintegration aid to improve dispersion in water. Such disintegration aids are well known in the art of laundry and machine dish-wash detergent tablets. Ready-to-use liquid abrasive cleaners can be obtained from the dry compositions by adding a suitable amount of water. Generally the amount of water should be such that the liquid product contains between 10% and 65% of solid abrasive, preferably between 10% and 60%, more preferably between 15% and 50%, and the product has a viscosity η₂ι of between 0.4 and 3.0 Pas. sec, preferably between 0.8 and 2.5 Pas. sec, more preferably between 1.0 and 2.0 Pas. sec.

Preferred compositions

Preferred dry compositions containing a surfactant based suspending system will generally have a composition as set out below:

Preferred dry compositions containing a polymeric thickener based suspending system will generally have a composition as set out below:

Examples

Example 1

A solid abrasive composition, containing a surfactant based suspending system, was prepared having the composition below:

LAS Acid 5.97

Lialet 111-5.5 1) 3.13

Omyacarb 30AV 2) 79.57

Sodium Carbonate 7.22

Prifac 7901 3) 0.90 Acusol 823 4) 0.03

Perfume 0.72 Proxel GXL 5) 0.028 Socal P2V 6) 1.00 Alusil 7) 0.75

Water 0.67

1) Ethoxylated alcohol nonionic surfactant marketed by Condea Chimica DAC

2) Calcite marketed by Omya, average particle size claimed to be 30 micron. 3) Fatty acid mixture marketed by UniQema

4) Polyacrylate marketed by Rohm & Haas

5) preservative supplied by Zeneca Biocides 6)

7) Aluminium silicate marketed by J Crosfield

The Omyacarb and sodium carbonate were warmed in the bowl of a RotoJunior 10L high speed mixer/granulator (Zanchetta & C. S.r.l., Italy) until the temperature had reached approx. 50 °C. LAS acid, warmed to 50 °C was added first and allowed to distribute throughout the solids mixture. Once dispersed, the nonionic/fatty acid/polymer/minors mixture (except free flowing agent and perfume) was added to the bowl. Both LAS acid and the nonionic mix were added slowly, as the agitator was turning (300rpm) , the time taken to add the liquids being approx. 2 minutes.

On completing the liquid addition, the RotoJunior run continues with the agitator, chopper (1400 rpm) and heating (65°C) on for a further 10 minutes. After this, the agitator and chopper are switched off, and the RotoJunior is cooled with water for 20 minutes to cool the product. Every 5 minutes the agitator is switched on again for a few seconds to mix. Then the free flowing agent is added (Socal U2 ) and the material discharged. Perfume is then added externally, using a spray gun and a keg.

Example 2

A solid abrasive composition, containing a polymeric thickener based suspending system, was prepared having the composition below:

Calcite 95

Carbopol ETD 2623 1) 0.36 (C16-18) alkyl-dimethylamine oxide 0.42

AMP (2-amino-2-methyl-propanol-l) 0.38

NaOH 1.00

Perfume 0.84

Water etc to 100%

1) Polyacrylate marketed by B F Goodrich.

The mixing process was carried out in a Kenwood Chef blender using ^λK' shaped attachment according to the procedure below:

1. Add Calcite to mixing bowl

2. Add polymer powder and mix together for approx. 5 mins, mixing speed set low to medium to avoid any loss of powder. The remaining ingredients are liquids added via a pipette.

3. Whilst mixing add AMP pre-dispersed in approx. 1% water 4. Add NaOH (10% solution), mix for approx. 5 mins

5. Add Amine Oxide

6. Add Perfume; mix until a satisfactory homogeneous mix is achieved. Approx. 20 mins.

Claims

1. A dry solid composition comprising a solid abrasive characterized in that it comprises a suspending system suitable to obtain a stable suspension on mixing with a liquid medium.

2. A dry abrasive composition according to claim 1 characterized in that it contains at least 65% of solid abrasive and at least 0.1% of suspending system.

3. A composition according to claim 2 characterized in that the amount of abrasive is at least 70%.

4. A composition according to claim 1-3 characterized in that the abrasive is water-insoluble.

5. A dry abrasive composition according to claims 1-5 characterized in that the suspending system is chosen such that that the suspension obtained after mixing the dry composition with an equal amount of water has the following flow properties: ηo is at least 2500 Pa.s σ_c is 2.5-25 η₂ι is at least 0.1 Pa.s

6. A composition according to claims 1-5 characterized in that the suspending system comprises one or more surfactants able to form a lamellar micelle phase on mixing with the liquid medium.

7. A composition according to claim 6 characterized in that the surfactants comprise an anionic surfactant and a nonionic surfactant.

8. A composition according to claims 1-5 characterized in that the suspending system comprises one or more polymeric thickening agents..

9. A composition according to claims 1-8 characterized in that it comprises at least 0.1% of a foaming surfactant.

10. A composition according to claims 1-9 characterized in that it comprises a free-flowing agent and/or a dispersing agent.

11. A composition according to claims 1-10 characterized in that it has been subjected to processing to make it free-flowing and easily dispersible.

12. A composition according to claim 11 characterized in that the processing is chosen from spray-drying, fluid bed drying and granulation.

13. A process for preparing liquid abrasive cleaning compositions comprising mixing a dry composition according to any one of claims 1-12 with a liquid medium.

14. A process according to claim 13 in which the liquid medium consists for at least 85% of water.

15. A process according to claims 13 or 14 characterized in that the ratio of liquid medium to dry composition is chosen such that the liquid abrasive cleaner contains 10-65% of solid abrasive.

16. A process according to claims 13-15 characterized in that the amount of liquid medium is chosen such that the liquid abrasive cleaner has a η₂ι of between 0.4 and 3.0 Pas. sec