MXPA04010187A - Cleaning compositions in the form of a tablet. - Google Patents

Abstract

A cleaning tablet which comprises 40-60 % of an alpha hydroxy aliphatic acid, 20-30 % of an alkali metal bicarbonate, a magnesium inorganic salt, a clay, a sulfonated anionic surfactant, an alkali polycarboxylate, a solubilizing agent and a salt of a fatty acid.

Description

CLEANING COMPOSITIONS IN THE FORM OF A TABLET Field of the Invention This invention relates to a concentrate of a cleaning composition containing a bleaching compound in the form of a tablet which has excellent foam collapsing properties and excellent anti-bacterial properties, excellent fat cutting properties and is particularly suitable for cleaning hard surfaces and which is effective to remove dirt and grease and / or dirt from the bathroom and to leave unrinsed surfaces with a shiny appearance.

Background of the Invention In recent years, liquid detergents have been widely accepted for all purposes to clean hard surfaces, for example, panels and painted wood work, tiled walls, washbasin containers, bath tubs, linoleum tile floors, washable wallpaper, etc. Such liquids for all purposes comprise transparent and opaque aqueous mixtures of water soluble synthetic organic detergents and water soluble detergent builder salts. In order to achieve a cleaning efficiency comparable to cleaning compositions for all powder or granular purposes, the use of water-soluble inorganic phosphate-reinforcing salts was favored in liquids for all purposes of the prior art. For example, such initial phosphate-containing cleaning compositions are described in U.S. Patent Nos. 2,560,839; 3,234,138; 3,350,319 and British patent 1,223,739.

In view of environmental efforts to reduce phosphate levels in the earth's water, liquids have appeared for all improved purposes that contain reduced concentrations of inorganic phosphate-reinforcing salts or phosphate-free reinforcing salts. A particularly useful self-opacifying liquid of the latter type is described in U.S. Patent No. 4,244,840.

However, these liquid detergents for all purposes of the prior art containing detergent reinforcing salts or other equivalents tend to leave films, stains or scratches on unrinsed and cleaned surfaces, particularly glossy surfaces. Such liquids require a complete rinsing of the cleaned surfaces which is a time-consuming task for the user.

In order to overcome the above disadvantage of the liquid for all purposes of the prior art, U.S. Patent No. 4,017,409 teaches that a mixture of paraffin sulfonate and a reduced concentration of an anionic phosphate-reinforcing salt should be employed. . However, such compositions are not completely acceptable from an environmental point of view based on the phosphate content. On the other hand, another alternative to achieve liquids for all phosphate-free purposes has been the use of a major proportion of a mixture of anionic and nonionic detergents with minor amounts of glycol ether solvent and organic amine as shown in the patent of the United States of America No. 3,935,130. Again, this approach has not been completely satisfactory and the high levels of organic detergents needed to achieve cleaning cause a foaming which, in turn, leads to the need for a complete rinse and which has been found to be undesirable by consumers. current consumers.

Another approach to formulate a liquid detergent composition for all purposes or hard surface where product homogeneity and clarity are important considerations that involve the formation of oil-in-water microemulsions (o / w) which contain one or more surfactant detergent compounds, a water immiscible solvent (typically a hydrocarbon solvent) and a "cosurfactant" compound which provides product stability. By definition, the oil-in-water microemulsion is a colloidal dispersion that spontaneously forms of "oil" phase particles having a particle size in the range of 25 to 800 Angstroms in a continuous aqueous phase.

In view of the extremely fine particle size of the dispersed oil phase particles, the microemulsions are transparent to light and clear and are usually highly stable against phase separation.

Patent disclosures relating to the use of grease removal solvents and oil-petticoat microemulsions include, for example, European patent applications EP 0137615 and EP 0137616 by Herbots et al .; European patent application EP 0160762 by Johnston et al. and US Pat. No. 4,561,991 by Herbots et al. Each of these patents also discloses the use of at least 5% by weight of a grease removal solvent.

It is also known from British patent application GB 2144763A of Herbots et al. Published on March 13, 1985, that magnesium salts improve the fat removal performance of organic fat removal solvents, such as terpenes in compositions of liquid detergent of oil-in-water microemulsion. The compositions of this invention described by Herbots et al. Require at least 5% of the mixture of grease removal solvent and magnesium salt, preferably at least 5% solvent (which can be a mixture of a non-solvent polar immiscible in water with a polar solvent slightly and sparingly soluble) and at least 0.1% magnesium salt.

However, since the amount of water-immiscible and sparingly soluble components that may be present in the oil-in-water microemulsion, with total active ingredients without harming the microemulsion is quite limited (eg up to 18% by weight of the aqueous phase) the presence of such high amounts of grease removal solvent tend to reduce the total amount of greasy or oily soils which can be taken by and into the microemulsion without causing a phase separation.

The following representative prior art patents also refer to liquid detergent cleansing compositions in the form of oil-in-water microemulsions: patents of the United States of America Nos. 4,472,291 issued to Rosario; 4,540,448 granted to Gauteer and others and 3,723,330 granted to Sheflin, etc.

Liquid detergent compositions which include terpenes, such as d-limonene or other fat removal solvent, even though they are not described as being in the form of oil-in-water microemulsions are the subject matter of the following representative patents : European patent application 0080749; British patent specification 1,603,047 and U.S. Patent No. 4,414,128 and 4,540,505. For example, U.S. Patent No. 4,414,128 broadly discloses a liquid detergent composition characterized by weight, by: (a) from 1% to 20% of an anionic, nonionic, amphoteric, or synthetic suteionic surfactant or mixtures thereof thereof; (b) from 0.5% to 10% of a monkey or sesquiterpene or mixture thereof at a ratio by weight of (a): (b) being in the range of 5: 1 to 1: 3 and (c) from 0.5% to 10% of a polar solvent having a solubility in water at 15 ° C in the range of 0.2% to 10%. Other ingredients described in the formulas described in this patent include from 0.5% to 2% by weight of an alkali metal, ammonium or alkanolammonium soap of a C 13 -C 24 fatty acid; a calcium sequestrant of from 0.5% to 13% by weight; a non-aqueous solvent, for example, alcohols and glycol ethers, up to 10% by weight; and hydrotrope, for example, urea, ethanolamines, salts of alkyl aryl sulfonates, and higher up to 10% by weight. All formulas shown in the examples of this patent include relatively large amounts of detergent reinforcing salts which are perceptible to surface gloss.

Synthesis of the Invention The present invention provides a cleaning system comprising a concentrate of a cleaning composition in a tablet form, which has excellent foam folding properties; good antibacterial properties and excellent grease-cutting property, which, when dissolved in a container, is suitable for cleaning hard surfaces such as plastic, glass and metal surfaces having a glossy finish, oil-stained floors, engines of automobile and other engines. More particularly, the improved cleaning compositions, with excellent foam-collapsing properties and excellent grease-cutting property exhibit good oil and grease removal properties due to the improved interfacial tensions, when used diluted and leave the surfaces clean bright without a need or requiring only a minimum additional rinsing or cleaning. The latter feature is evidenced by the very few or no visible residues on the cleaned unrinsed surfaces and, therefore, overcomes one of the disadvantages of the prior art products.

Surprisingly, these desirable results are desired even in the presence of polyphosphate and other inorganic or organic detergent builder salts and also in the complete absence or in the essentially complete absence of the fat removal solvent.

This invention relates to all cleaning detergents for all purposes in tablet form which dissolve rapidly to give an adequate cleaning solution or variety of domestic light duty cleaning tasks such as in the kitchen or in the bathroom. The tablet contains a bleaching compound and an effervescent system consisting of an organic acid and a sodium bicarbonate to give a signal of effectiveness as it dissolves. In addition, while the card is dissolved it can also optionally contain a bleach and two polymeric disintegrators which help to disintegrate the tablet when it is added to the water. Tablets can be made, such as a single layer tablet with colored spots for aesthetic benefits or can be a multi-layer tablet with different colored layers.

In one aspect, the invention generally provides a single-layer or multi-layer tablet which comprises by weight: (a) from 40% to 60% of an alpha hydroxy aliphatic acid such as a lactic acid or a citric acid: (b) 20% to 30% of an alkali metal bicarbonate such as sodium bicarbonate or potassium bicarbonate; (c) 2% to 8% of an inorganic salt containing magnesium selected from the group consisting of magnesium sulfate, magnesium oxide and magnesium chloride and mixtures thereof; (d) 1% to 9% of a clay; (e) 1% to 10% of a sulphonated anionic surfactant; (f) 0.1% to 4% of an alkali metal salt of a polycarboxylic acid; (g) 0.1% to 4% of a solubilizing agent; (h) 0.5% to 1% of an alkali metal or alkaline earth metal salt of a fatty acid such as magnesium stearate; (i) 0 to 5%, more preferably 0.1% to 3% of an ethoxylated nonionic surfactant; (j) 0 to 5%, more preferably 0.1% to 4% of a green citric acid in the form of specks such as green specks; (k) 0 to 5% more preferably 0.1% to 4% of a blue colored citric acid in the form of specks such as blue specks; (1) 0 to 20% more preferably from 1% to 20% of a bleaching compound; (m) 0 to 2.5% more preferably 0.1% to 2% of a perfume.

In other aspects, the invention generally provides a single-layer or multi-layer tablet which comprises by weight: (a) from 20% to 50% of an alpha hydroxy aliphatic acid such as lactic acid or citric acid; (b) from 25% to 45% of an alkali metal bicarbonate such as sodium bicarbonate or potassium bicarbonate; (c) from "1% to 15% of an alkali metal carbonate such as potassium and / or sodium carbonate and mixtures thereof; (d) 1% to 9% of a clay; (e) 1% to 10% of a sulphonated anionic surfactant; (f) 2% to 12% of a C4-C12 aliphatic dicarboxylic acid such as an adipic acid; (g) 0.1% to 6%, more preferably 0.25% to 4% of a precipitated amorphous silica; (h) 0 to 5% of a blue or green dye; (i) 0 to 6%, more preferably 0.1% to 4% of a sodium sulfate; Y (j) 0 to 20% more preferably, 1% to 20% of a bleaching compound; Y (k) 0 to 2.5%, more preferably 0.1% to 2% of a perfume.

Detailed description of the invention The present invention relates to a tablet containing a unit dose of a cleaning composition.

A liquid cleaning composition contained in the form of a single-layer or multi-layer tablet comprises by weight: (a) 40% to 60% of an alpha hydroxy aliphatic acid such as lactic acid or citric acid; (b) 20% to 30% of an alkali metal bicarbonate such as sodium bicarbonate or potassium bicarbonate; (c) 2% to 8% of an inorganic salt containing magnesium selected from the group consisting of magnesium sulfate, magnesium oxide, magnesium chloride and mixtures thereof; (d) 1% to 9% of a clay (e) 1% to 10% of a sulphonated anionic surfactant; (f) 0.1% to 4% of an alkali metal salt and a polycarboxylic acid; (g) 0.1% to 4% of a solubilizing agent; (h) 0.5% to 1% of an alkali metal or alkaline earth metal salt of a fatty acid such as magnesium esters; (i) from 0 to 5%, more preferably from 0.1% to 3% of an ethoxylated nonionic surfactant; (j) from 0 to 5%, more preferably 0.1% to 4% of a green citric acid in the form of specks; (k) 0 to 5% more preferably 0.1% to 4% of a blue colored citric acid in the form of specks; (1) O to 20% more preferably from 1% to 20% of a bleaching compound; Y (m) 0 to 2.5% more preferably 0.1% to 2% of a perfume.

Another liquid cleaning composition contained in the form of a single-layer or multi-layer tablet comprises by weight: (a) 20% to 50% of an alpha hydroxy aliphatic acid such as lactic acid or citric acid; (b) 25% to 45% of an alkali metal bicarbonate such as sodium bicarbonate or potassium bicarbonate; (c) 1% to 15% of an alkali metal carbonate such as potassium carbonate and / or sodium carbonate; (d) 1% to 9% of a clay; (e) 1% to 10% of a sulphonated anionic surfactant; (f) 2% to 12% of a C4-C12 aliphatic dicarboxylic acid such as an adipic acid; (g) 0.1% to 6%, more preferably 0.25% to 4% of a precipitated amorphous silica; (h) 0 to 5% of a blue or green dye; (i) 0 to 6%, more preferably 0.1% to 4% of a sodium sulfate; Y (j) 0 to 20% more preferably, 1% to 20% of a bleaching compound; Y (k) 0 to 5.0%, more preferably 0.1% to 4% of a perfume.

As used herein and in the appended claims, the term "perfume" is used in its ordinary sense to refer to and include any fragrant substance not soluble in water or a mixture of substances including natural odoriferous substances (e.g. obtained by the extraction of flowers, artificial herbs or plants) (for example mixtures of natural oils or constituents of oils) and synthetically produced substances). Typically perfumes are complex mixtures of combinations of various organic compounds such as alcohols, aldehydes, esters, aromatics and varying amounts of essential oils (e.g., terpenes) such as from 0% to 80%, usually from 10% to 70% by weight, the essential oils themselves being volatile odoriferous compounds and also serving to dissolve other components of the perfume.

In the present invention, the precise composition of the perfume is not of a particular consequence for cleaning performance as long as it satisfies the criterion of immiscibility in water and has a pleasant smell. Naturally, of course, in a special way for the cleaning compositions intended for use in the home, the perfume as well as other ingredients must be cosmetically acceptable, for example non-toxic, hypoallergenic, etc.

The nonionic surfactant which can be used in a present cleaning composition is selected from the group of an aliphatic ethoxylated nonionic surfactant and an aliphatic ethoxylated / propoxylated nonionic surfactant and mixtures thereof.

The water-soluble aliphatic ethoxylated ethoxylated surfactants used in this invention are known and include the primary aliphatic alcohol ethoxylate and the secondary aliphatic alcohol ethoxylates. The length of the poliethenoxy chain can be adjusted to achieve the desired balance between the hydrophobic and hydrophilic elements.

The class of nonionic surfactant includes the condensation products of a higher alcohol (for example an alkanol containing 8 to 16 carbon atoms in a straight or branched chain configuration) condensed with 4 to 20 moles of ethylene oxide) by example lauryl or myristyl alcohol condensed with 16 moles of ethylene oxide (EO), tridecanol condensed with 6 to 15 moles of ethylene oxide, myristyl alcohol with 1G moles of ethylene oxide per mole of myristyl alcohol, the condensation product of ethylene oxide with a coconut fatty alcohol cut containing a mixture of fatty alcohols with alkyl chains ranging from 10 to 14 carbon atoms in length wherein the condensate contains either six moles of ethylene oxide per mole of total alcohol and alcohol ethoxylates bait containing 6 ethylene oxide to 11 ethylene oxide per mole of alcohol.

The preferred group of the above nonionic surfactants are the Neodol ethoxylates (from Shell Company) which are a higher aliphatic primary alcohol containing 9-15 carbon atoms such as a Cg-Cn alkanol condensed with 4 to 10 moles of ethylene (Neodol 91-8 or Neodol 91-5), C12-C15 alkanol condensed with 6.5 moles of ethylene oxide (Neodol 23-6.5), C12-C15 alkanol condensed with 13 moles of ethylene oxide (Neodol 45-3) and similar. Such etaxomers have a HLB (lipophilic hydrophobic balance) value of 8 to 15 and give a good oil / water emulsification, while the etaxomers with lipophilic hydrophobic balance values below 7 contain less than four ethylene oxide groups and tend to be emulsifiers poor and poor detergents.

The further satisfactory water-soluble ethylene oxide condensates are the condensation products of a secondary aliphatic alcohol containing from 8 to 18 carbon atoms in a straight or branched chain configuration condensed with 5 to 30 moles of ethylene oxide . Examples of commercially available nonionic detergents of the above type are the secondary alkanol Cn-Ci5 condensed with either 9 ethylene oxide (Tergitol 15-S-9) or 12 ethylene oxide (Tergitol 15-S-12) marketed by Union Carbide One of the water-soluble nonionic surfactants which can be used in this invention are the aliphatic ethoxylated / propoxylated non-ionic surfactants which are shown by the formula: R- O- (CH2CH20) x (CH2CH2CH2) 3 H? Where R is a branched chain alkyl group having from 10 to 17 carbon atoms, preferably an isotridecyl group and wherein x and y are independently numbered from 1 to 20.

Suitable water-soluble detergents used in the present compositions include those detergent or surfactant compounds which contain an organic hydrophobic group which generally contains from 8 to 26 carbon atoms preferably from 10 to 18 carbon atoms in its molecular structure and at least a water solubilizing group selected from the sulfonate, sulfate and carboxylate group to form a water soluble detergent. Usually, the hydrophobic group will include or comprise an alkyl, C8-C22 alkyl or acyl group. Such surfactants are used in the form of water-soluble salts and the salt-forming cation is selected from the group consisting of sodium, potassium, ammonium, magnesium and mono-di- or tri-alkanolammonium C2-C3 with the sodium cations , magnesium and ammonium again being preferred.

Examples of the sulfonated anionic surfactants suitable for use in the present compositions are the well-known higher alkyl mononuclear aromatic sulphonates such as the higher alkylbenzene sulfonates containing from 10 to 16 carbon atoms in the higher alkyl group in a straight or branched chain, the toluene sulphonates of C8-Ci5 alkyl and the alkyl phenol sulphonates Ce-Cis.

A preferred sulfonate is a linear alkyl benzene sulfonate having a high content of 3- (or higher) phenyl isomers and a correspondingly low content (well below 50%) of 2- (or lower) phenyl isomers, ie , wherein the benzene ring is preferably held in the large part in position 3 or higher (for example, 4, 5, 6, or 7 of the alkyl group) and the content of isomers in which the benzene ring is held in position 2 to 1 is correspondingly low. Particularly preferred materials are set forth in U.S. Patent No. 3,320,174.

Other suitable anionic surfactants are olefin sulfonates, including long-chain alkene sulfonates, long-chain hydroxyalkane sulfonates or mixtures of alkene sulphonates and hydroxy alkane sulfonates. These alginate sulfonate detergents can be prepared in a known manner by the reaction of sulfur trioxide (S03) with long chain de? Ns and containing 8, preferably from 12 to 21 carbon atoms and having the formula RCH = CHRi wherein R is an upper alkyl group of 6 to 23 carbons and R is an alkyl group of 1 to 17 carbons or hydrogen to form a mixture of sultones and sulfonic acid alkene which is then treated to convert the sultones to sulfonates. Preferred olefin sulfonates contain from 14 to 16 carbon atoms in the alkyl group R and are obtained by sulfonating an alpha olefin.

Other examples of suitable anionic sulfonate surfactants are paraffin sulphonates containing 10 to 20, preferably 13 to 17, carbon atoms. The primary paraffin sulfonates are made by reacting the long chain alpha olefins and paraffin sulphonates and sulfonates having a sulfonate group distributed to. along the paraffin chain and are shown in U.S. Patent Nos. 2,503,280; 2,507,088; 3,260,744; 3,372,188 or German Patent No. 735,096.

The clays which are used in the present compositions are the inorganic colloid formable clays of the smectite and / or attapulgite type. These materials are generally used in amounts of 0.5% by weight to 10% by weight, preferably 1 to 9% by weight.

Smectite clays include montmorillonite (bentonite) hectorite, smectite, saponite and the like. Montmorillonite clays are available under trade names such as Thixogel (registered trademark) No. 1 and Gelwhite (registered trademark) GP, H etc., from Georgia Kaolin Company etc.,; and ECCAGU (registered trademark) GP H, etc., of Luthern Clay Products. Attapulguite clays include materials commercially available under the trademark Attagel (trademark) for example Attagel 40, Attagel 50 and Attagel 150 from Engethard Minerals and Chemicals. Mixtures of the smectite and attapulguite types from 4: 1 to 1: 5 are also used here. Another clay is a clay is a bentonite that contains a blue, green or pink dye which is manufactured by Larivosa Chimica Milenaria S. p. A. Detercal P4 ™. A more preferred clay is the laponite clay manufactured by Southern Clay.

A bleaching compound may be optionally employed in the compositions of this invention. Preferred bleaching compounds chlorine bleach such as dichloroisocyanurate, dichloro-dimethylhydantoin or chlorinated TSP, the alkali metal or the alkaline earth metal, for example potassium, lithium, magnesium, especially sodium hypochlorite are preferred.

The alkali metal salt of the crosslinked poly acrylic acid polymer of poly acrylic acid which has the structure of: Where n is a sufficient number to provide a polymer with a molecular weight of 400,000 to 2,000,000, more preferably from 400,000 to 1,500,000 and X is an alkali metal or alkaline earth metal cation. A preferred crosslinked poly acrylic acid polymer is Acusol 771 ™ manufactured by Rohm and Haas Company.

The solubilizing agent improves the solubility of the tablet in water when it is added to water. The solubilizing agent is a? -2-polyvinyl pyrrolidone having a particle sizes of 15 to 125 microns. Polyvinyl pyrrolidone is manufactured by International Specialty Corporation under the trade name Polyplasdone ™ XL (100 microns) or Polyplasdone ™ XL-10 (30 microns).

The lubricant used in the cleaning tablet is employed to improve the process for manufacturing the tablet by improving the release of the tablet from the mold during manufacture. The lubricant is an alkali metal salt of a fatty acid having from 8 to 22 carbon atoms such as a sodium stearate, magnesium stearate or potassium stearate and is used in the concentration of 0.5 to 2% by weight, more preferably from 0.1 to 1.0% by weight.

The tablets present may also contain 0 to 5.0% by weight, more preferably from 0.1% to 4% by weight of a fragrance. The present compositions may optionally contain 0 to 15% by weight of an enzyme amylase, protease or lipase and mixtures thereof.

The cleaning composition of this invention can, if desired, also contain other components either to provide the additional effect or to make the product more attractive to the consumer. The following are mentioned by way of example in various colors or inks in amounts up to 0.5% by weight; bactericides in amounts of up to 1% by weight; preservatives or antioxidant agents, such as formalin, 5-bromo-5-dioxane-1, 3; 5-chloro-2-methyl-4-isotaliozalin-3-one, 2,6-di-tert.butyl-p-cresol, etc., in amounts of up to 2% by weight. A final form, cleaning compositions which contain less than 5% by weight of water exhibit stability at reduced and increased temperatures.

The process for making tablets contains two steps. Dry mix the formula amounts of powders with an overspray of non-ionic liquid and fragrance. Any necessary color solutions are also sprayed at this time and then the resulting powder is run through a tablet press which has mole to prepare tablets of a desired shape, size and weight desired. The powders are added to the mixer (a twin shell mixer or other suitable mixer).

The powder is then added to a rotating press having from 19 to 30 moles. The tablets are pressed at high speed (5 per second). When leaving the press these are channeled to the packaging line. The tablets may be generally in any form, but preferably they are elliptical in shape and the tablets may be elongated in the shape with arched ends such as an oval shape or a circular, square or rectangular shape.

The following examples illustrate the liquid cleaning compositions of the described invention. Unless otherwise specified the proportions in the film and in other parts of the description are by weight.

Example 1 The following formula was prepared in percent by weight by simple mixing and then formed into a tablet: The tablet containing the aforementioned formulas was dissolved in 3 liters in two liters of water in a container. This formula usually foamed during the solution and subsequent use.

Example 2 The following formula was prepared in% by simple mixing and then formed into a tablet.

The tablet contained in the aforementioned formulas was dissolved in 3 minutes in 2 liters of water in a container. This formula generates foams during dissolution and subsequent use. For example, at a typical concentration of 0.4% in tap water (23 ° C) this formula generates 180 ml of foam in an inverted cylinder foam test (instant foam).

Example 3 The following formula was prepared in% by weight by simple mixing and then a tablet was formed: Sodium bicarbonate 36.20 Citric acid 35.50 Adipic acid 7.50 Sodium carbonate 7.O0 Bentonite clay 4.55 Sodium dodecyl benzene sulfonate 4.25 Perfume 3.00 Precipitated synthetic amorphous silica 0.75 Sodium sulfate 0.60 Pigment blue 15 (C174160) 0.40 Clay laponite RD 0.05 The tablet containing the aforementioned formulas was dissolved in three minutes in two liters of water in a container.

Claims (9)

R E I V I N D I C A C I O N S

1. A cleaning tablet which comprises by weight: (a) 40% to 60% of an alpha hydroxy aliphatic acid; (b) 20% to 30% of an alkali metal bicarbonate; (c) 2% to 8% of an inorganic salt containing selected magnesium; (d) 1% to 9% of a clay (e) 1% to 10% of a sulphonated anionic surfactant; (f) 0.1% to 4% of an alkali metal salt and a polycarboxylic acid; (g) 0.1% to 4% of a solubilizing agent; Y (h) 0.5% to 1% of an alkali metal or alkaline earth metal salt of a fatty acid such as magnesium stearate.

2. A cleaning tablet as claimed in clause 1, characterized in that it includes a non-ionic surfactant.

3. A cleaning tablet as claimed in clause 1, characterized in that it includes a perfume.

4. A cleaning tablet as claimed in clause 3, characterized in that it includes colored specks of citric acid blue and / or green colored specks of citric acid.

5. A cleaning tablet as claimed in clause 1, characterized in that it contains 1% to 20% by weight of a bleaching compound.

6. A cleaning tablet which comprises by weight: (a) from 25% to 50% of an alpha hydroxy aliphatic acid; (b) from 25% to 43% of an alkali metal bicarbonate; (c) from 1% to 15% of an alkali metal carbonate; (d) from 1% to 95 of a clay; (e) 1% 10% of a sulphonated anionic surfactant; (f) from 2% to 11% of a C4-C12 aliphatic dicarboxylic acid; from 1% to 20% of a bleach-containing compound; (h) from 0.1% to 6% of an amorphous precipitated silica.

7. A cleaning tablet as claimed in clause 6, characterized in that said clay is a laponite clay.

8. A cleaning tablet as claimed in clause 6, characterized in that it also comprises perfume.

9. A cleaning tablet as claimed in clause 1, characterized in that it includes 1% to 20% by weight of a bleaching compound. SUMMARIZES A cleaning tablet which comprises 40-60% of an alpha-hydroxy aliphatic acid, 20-30% of alkali metal bicarbonate, an inorganic magnesium salt, a clay, a sulphonated anionic surfactant, an alkyl polycarboxylate, a solubilizing agent and a salt of fatty acid.