WO2007099313A1

WO2007099313A1 - A cleaning block

Info

Publication number: WO2007099313A1
Application number: PCT/GB2007/000699
Authority: WO
Inventors: Malcolm Tom Mckechnie
Original assignee: Reckitt Benckiser (Uk) Limited
Priority date: 2006-03-03
Filing date: 2007-02-28
Publication date: 2007-09-07
Also published as: GB0604238D0

Abstract

A cleaning block comprising at least a first portion and a second portion, said portions having different bulk densities, wherein, upon addition of the block to a column of water, at least part of the first portion disperses and/or dissolves such that the block moves up or down the column of water.

Description

A Cleaning Block

. The present invention relates to cleaning blocks and their method of preparation.

Cleaning blocks, such as lavatory cleaning blocks, are well known. Such blocks, are typically designed to release active materials throughout their life. Lavatory cleaning blocks typically fall into two categories: in-the-bowl (ITB) lavatory blocks and in-the-cistern (ITC) lavatory blocks. An ITB lavatory block may be placed in a cage and suspended from the rim of a toilet bowl . Positioned in this way, the block comes into contact with water every time the toilet is flushed, releasing active materials, such as fragrances and cleaning agents, into the toilet bowl.

An ITC lavatory block is intended to be placed in the cistern of a lavatory. When immersed in the water in the cistern, the block dissolves to produce an aqueous solution of active materials. This solution is released into the lavatory bowl when the lavatory is flushed.

Conventional ITC lavatory blocks tend to dissolve gradually from a static source. Thus, although active materials are eventually dispersed in the water in the cistern, mixing can be relatively slow, as the water in the cistern can remain unagitated for prolonged periods of time. To aid mixing, the water in the cistern may be stirred using external mixing means. However, it may not be possible to mix the water continually over an extended period of time. It is also impossible to release of active materials at particular target sites within the cistern.

According to a first aspect of the present invention there is provided a cleaning block comprising at least a first portion and a second portion, said portions having different bulk densities, wherein, upon addition of the block to a column of water, at least part of the first portion disperses and/or dissolves such that the block moves up or down the column of water.

The present invention will now be further described. In the following passages different aspects of the invention are defined in more detail . Each aspect so defined may be combined with any other aspect or aspects unless clearly indicated to the contrary. In particular any feature indicated as being preferred or advantageous may be combined with any other feature or features indicated as being preferred or advantageous.

In the cleaning block of the present invention, the first portion and second portion have different bulk densities. In other words, the mass to volume ratio of the first portion is different to that of the second portion. Accordingly, the first and second portions have different buoyancies. When the cleaning block is placed in a column of water, at least part of the first portion disperses and/or dissolves. As a result, the density of the block changes, causing the block to move up or down the column of water. This movement may allow active agents in the block to be delivered to different target sites within the column of water. This movement may also aid mixing of the active agents .

The first portion of the cleaning block may be formed of a first composition and the second portion of the cleaning block may be formed of a second composition. The first composition may have a different specific density to the second composition. Alternatively, the first composition may have the same specific density as the second composition. In this instance, however, the first composition is compressed or packed to a different degree to the second composition. Accordingly, the bulk densities of the resulting portions are different.

The bulk densities of the portions may also be varied by the use of buoyancy aids. For example, buoyancy aids, such as polystyrene beads, may be included in the first and/or second composition to reduce the bulk density of the resulting portion. The compositions may also be aerated to different degrees to vary their buoyancies. As a further alternative, oil may be included in the composition to increase its buoyancy. The oil may be mixed with the other components of the composition. Alternatively, capsules containing the oil may be included.

The weight ratio of the first portion to the second portion may be 9:1 to 1:9.

As mentioned above, the first portion of the cleaning block at least partially disperses and/or dissolves in water. The second portion may also at least partially disperse and/or dissolve. In one embodiment, the first portion and second portion dissolve and/or disperse at different rates. Preferably, the first portion and second portion of the cleaning block disperse and/or dissolve in water, such that the cleaning block completely dissolves and/or disperses when used. In one embodiment/ the cleaning block completely dissolves and/or disperses over a period of 30 seconds to 24 hours, preferably 1 minute to 12 hours, depending on the intended use of the block. If the block is used as an ITC block or ITB block, the block may completely dissolve and/or disperse over a period of, for example, 3 to 24 hours, for example 6 to 12 hours. If the block is. intended to be placed in a container (e.g. bucket) of water to form an aqueous hard surface cleaner, the block may completely dissolve and/or disperse over a period of 30 seconds to 10 minutes, for example 1 to 5 minutes.

The cleaning block may include two or more portions formed from the first composition. Alternatively or additionally, the cleaning block may include two or more portions formed from the second composition. For example, the cleaning block may have layers formed from the first composition alternating with layers formed from the second composition. Alternatively, portions formed from the first composition may be dispersed within a matrix formed from the second composition and vice-versa. As a further alternative, at least one portion of the first composition may partially or completely surround at least a portion of the second composition and vice-versa. For example, the block may be formed of alternating or concentric shells of the first composition and second composition. The configuration and/or position of each of the portions within the cleaning block may have an affect on the buoyancy of the cleaning block in water. Accordingly, it may be possible to control the movement of the block up and/or down column of water by varying the configuration and/or position of the respective portions within the cleaning block. In a preferred embodiment, the buoyancy of the block- is controlled such that it moves up and down a column of water as it disperses and/or dissolves. This may be achieved by ensuring that the overall bulk density of cleaning block varies from being greater than that of water to being less than that of,. water. For example, the density of the block may vary from 0.5 to 1.5 g/cm³, preferably 0.7 to 1.3 g/cm³, more preferably 0.8 to 1.2 g/cm³, and yet more preferably^' 0.9 to 1.1 g/cm³.

The first portion may have a bulk density ranging from 0.5 to 1.5 g/cm³, preferably 0.7 to 1.3 g/cm³, more preferably 0.8 to 1.2 g/.cm³, and yet more preferably 0.9 to 1.1 g/cm³. The second portion may have a bulk density ranging from 0.5 to 1.5 g/cm³, preferably 0.7 to 1.3 g/cm³, more preferably 0.8 to 1.2 g/cm³, and yet more preferably 0.9 to 1.1 g/cm³.

As well as portions formed from the first composition and the second composition, the cleaning block may include at least one further portion formed from a further composition.

Accordingly, the cleaning block may include at least three portions; one formed from the first composition, another, from the second composition and a third formed from the further composition. This further composition may have the same or different bulk density to the first composition.

The further composition may also have the same and/or different bulk density to the second composition. The further portion (s) may have a bulk density of 0.5 to 1.5 g/cm³, preferably 0.7 to 1.3 g/cm³, more preferably 0.8 to 1.2 g/cm³, and yet more preferably 0.9 to 1.1 g/cm³.

Advantageously, the further portion (s) at least partially dissolves and/or disperses in water. This portion may dissolve and/or disperse at a slower, faster or same rate than the first portion and/or second portion. The configuration and/or position of this further portion (s) within the cleaning block may also have an affect on the cleaning block's buoyancy.

The cleaning block of the present invention may be used to form an aqueous hard surface cleaning composition. For example, the cleaning block may be at least partially dissolved and/or dispersed in water to form a hard surface cleaning composition. In one embodiment, the cleaning block is at least partially dissolved and/or dispersed to form a cleaner for drain pipes, such as the U-bend from a sink or shower. In another embodiment, the cleaning block is at least partially dissolved and/or dispersed in water to form a floor cleaner. Accordingly, the cleaning block may be placed in a bucket of water, and allowed to dissolve and/or disperse to form an aqueous floor cleaning composition.

This aqueous floor cleaning composition may then be applied using a mop or cloth.

In a preferred embodiment, the cleaning block is a lavatory cleaning block, such as an ITB or ITC lavatory cleaning block. More preferably, the block is placed in the cistern of a lavatory and allowed to dissolve and/or disperse in the water in the cistern. The resulting solution is released into the lavatory bowl when the toilet is flushed.

The cleaning block of the present invention may include an active agent selected from at least one of a surfactant, anti-limescale agent and/or bleaching agent. Thus, each portion of the cleaning block may also include at least one of such active agents. Optionally, enzymes, dyes, pigments, preservatives, fillers, binders and/or solubility control agents may also be present in one or more of the portions of the block. Other optional components include acids, alkalis, chelating agents, dispersing agents and effervescent agents. Each of the active agents may be present in the same or different concentrations in the different portions of the block depending on the effect desired. In one embodiment, it is desirable to include a fragrance and/or an anti-limescale agent in the portion of the block having a relatively low density to ensure that these components are released towards the surface of the column of water. It may also be desirable to include an enzyme or bleaching agent in the portion of the block having a relatively high density to ensure that these components are released in a deeper region of the column of water.

Where a surfactant is employed, the surfactant may be present in one or more of the compositions of the block. For example, the surfactant may be used in the first composition, the second composition and/or the further composition. The surfactant may be included in the first composition, second composition and/or further composition in an amount of 0.1 to 90 weight %, preferably 0.5 to 20 weight %, more preferably 1 to 5 weight % based on the total weight of each composition. The overall concentration of surfactant in the block may 0.1 to 90 weight %, preferably 0.5 to 20 weight %, more preferably 1 to 5 weight % based on the total weight of the block.

Suitable surfactants include anionic, cationic and nonionic surfactants. Examples of anionic surfactants include alkali metal salts of alkyl substituted benzene sulfonic acids, alkali metal salts of long chain fatty sulfates, alkali metal salts of long chain fatty sulfonates, alkali metal ether sulfates derived from phenols, alkali metal sulfosuccinates and alkali metal sarcosinates . For example, sodium or potassium salts of alkyl substituted benzene sulfonic acids, long chain fatty sulfates, long chain fatty sulfonates and ether sulfates derived from phenols may be used. Sodium or potassium sulfosuccinates and alkali metal sarcosinates may also be suitable .

Examples of cationic surfactants are quaternary ammonium bromides and chlorides containing long chain alkyl groups, such as benzalkonium chloride.

Examples of nonionic surfactants include those of the betaine and imidazoline-type . Other examples include ethoxylated C₆-C₂4 fatty alcohol non-ionic surfactant, fatty acid C₆-C₂4 alkanolamides, C₆-C₂O polyethylglycol ethers, polyethyleneglycol with a molecular weight of 1000 to 80000 and C₆-C₂4 amine oxides.

Where an anti-limescale agent is employed, the anti- limescale agent may be present in one or more of the compositions of the block. For example, the anti-limescale agent may be used in the first composition, the second composition and/or the further composition. The anti- limescale agent may be included in the first composition, second composition and/or further composition in an amount of 0.1 to 90 weight %, preferably 1 to 50 weight % based on the total weight of each composition. The overall concentration of anti-limescale agent in the block may be 0.1 to 90 weight %, preferably 1 to 50 weight %.

Examples of anti-limescale agents are phosphonates, phosphates, formats, polycarboxylic acid and polyaspartic acid and citrates. The counter ion may be, for example, silver or zinc. Zeolites may also be used.

Where a bleaching agent is employed, the bleaching agent may be present in one or more of the compositions of the block. For example, the bleaching agent may be used in the first composition, the second composition and/or the further composition. The bleaching agent may be included in the first composition, second composition and/or further composition in an amount of 0.05 to 50 weight %, preferably 0.1 to 6 weight % based on the total weight of each composition. The overall concentration of bleaching agent in the block may be 0.05 to 50 weight %, preferably 0.1 to 6 weight %.

Examples of bleaching agents which may be used are solid halogen release agents such as alkali metal or alkaline earth metal hypochlorites, halogenated isocyanuric acid and alkali metal salts thereof and chlorinated dimethyl hydantoin. Peroxy and perborate compositions may be . contemplated in appropriate formulations. Enzymatic bleaching systems, such as laccases, may also be used.

Where an enzyme is employed, the enzyme may be present in one or more of the compositions of the block. For example, the enzyme may be used in the first composition, the second composition and/or the further composition. The enzyme may be included in the first composition, second composition and/or further composition in an amount of 0.1 to 20 weight %, preferably 0.5 to 10 weight % based on the total weight of each composition. The overall concentration of enzyme in the block may be 0.1 to 20 weight %, preferably 0.5 to 10 weight % . >

Suitable enzymes are lipases, proteases, cellulases, amylases, polysaccharide hydrolases and mixtures thereof. The preferred enzyme is lipase. The enzymes are used herein may be stain removal agents .

Commercially available enzymes for use herein include:

- protease of Bacillus, especially from B. licheniformis (e.g. Alcalase^® and from alkalophilic. Bacilus strains according to US 3 723 250 (e.g. ^■ Savinase^® (both available from Novo Industri A/S . - Alpha-amylase of Bacillus, especially B. licheniformis, Termamyl^® (Novo Industri A/S) .

- Protease of Fusarium, especially F. oxysporum, US 3 652 399 (Takeda) , PCT/DK 89/00001.

- Cellulase of Humicola,, especially H.Insolens. Celluzyme^®. (Novo Industri A/S. US 4,435,307 (Novo). Lipase of Humicola, especially H. lanuginose, Lipolase^® (novo) , EP 305 216 (Novo) and US 4,810,414 (Novo) .

Where a dye or pigment is employed, the dye or pigment may be present in one or more of the compositions of the block. For example, the dye or pigment may be used in the first composition, the second composition and/or the further composition. The dye or pigment may be included in the first composition, second composition and/or further composition in an amount of 0.001 to 10 weight %, preferably 0.1 to 5 weight % based on the total weight of each composition. The overall concentration of dye in the block may be 0.001 to 10 weight %, preferably 0.1 to 5 weight %.

Examples of dyes are Solvent Yellow 98 from Hoechst or Solvent Blue 70 from BASF. The choice of colour is arbitrary and any suitable colourants known in the art may be used.

Where a preservative is employed, the preservative may be present in one or more of the compositions of the block. For example, the preservative may be used in the first composition, the second composition and/or the further composition. The preservative may be included in the first composition, second composition and/or further composition in an amount of 0.001 to 10 weight %, preferably 0.01 to 5 weight % based on the total weight of each composition. The overall concentration of preservative in the block may be 0.001 to 10 weight %, preferably 0.01 to 5 weight %. Examples of preservatives are IRGASAN DP 300 (trade mark) or VENTOCIL IB (trade mark) .

Where a filler is employed, the filler may be present in one or more of the compositions of the block. For example, the filler may be used in the first composition, the second composition and/or the further composition. The filler may be included in the first composition, second composition and/or further composition in an amount of 0.1 to 50 weight %, preferably 1 to 20 weight % based on the total weight of each composition. The overall concentration of filler in the block may be 0.1 to 50 weight %, preferably 1 to 20 weight % .

Examples of fillers include inorganic salts such as sodium sulphate, sodium carbonate and sodium silicate. Alternatively or additionally, silica, clay, urea or calcite may be used. The fillers may be used to adjust the properties of the cleaning blocks so that the active agents are released in the desired manner.

The rate of dissolution of each portion of the block may be controlled by the optional addition to these portion of at least one solubility control agent. Suitable solubility control agents usually include materials having a solubility which is lower than readily soluble components (principally surfactants) of the portions. Such solubility control agents may vary in nature from substantially wholly water- soluble materials to materials having a low solubility in water. The solubility control agent may be present in different amounts in the first portion and the second. portion, and/or different solubility control agents may be present in the first portion and the second portion.

Examples of substantially insoluble solubility control agents are paradichlorobenzene, waxes such as beeswax, carnauba wax and petroleum waxes long chain fatty acids and alcohols and esters thereof and fatty alkylamides. Solubility control agents of limited aqueous solubility may also be used; examples thereof are known to those skilled in the art. Typically these can include various non-ionic surfactants. Suitable solubility control agents are those which can withstand the conditions of manufacture of the block (for example the pressure and temperature used in an extrusion process) .

The solubility control agent may be included in the first composition, second composition and/or further composition in an amount of 0.1 to 20 weight %, preferably 0.1 to 5 weight % based on the total weight of each composition. The overall concentration of solubility control agent in the block may be 0.1 to 20 weight %, preferably 0.1 to 5 weight

Optionally the block may comprise an acid or an alkali. The acid or alkali may be present in one or more of the compositions of the block. For example, the acid or alkali may be used in the first composition, the second composition and/or the further composition. The acid may be included in the first composition, second composition and/or further composition in an amount of 0.001 to 5 weight %, preferably 0.1 to 20 weight % based on the total weight of each composition. The overall concentration of acid in the block may be 0.001 to 5 weight %, preferably 0.1 to 20 weight %. The alkali may be included in the first composition, second composition and/or further composition in an amount of 0.001 to 5 weight %, preferably 0.1 to 20 weight % based on the total weight of each composition. The overall concentration of alkali in the block may be 0.001 to 5 weight %, preferably 0.1 to 20 weight %.

As mentioned above, the cleaning block of the present invention is intended to be dissolved/dispersed in water. The acid or alkali may be used to control the pH of that water. It may be desirable to control the pH from 0 to 13, preferably 2 to 11. For example in the case of a toilet block, the acid or alkali may be used to ensure that the water in the lavatory is in the range of pH 2 to 11, preferably 4 to 10. The stability and activity of the enzymes of the present invention can be optimised by ensuring the pH of the column of water is at the optimum level for the enzyme used.

Inclusion of acids in the compositions of the present invention may have an additional advantage that they may form small concentrations of the corresponding peracids by reaction with hydrogen peroxide in-situ, thus enhancing the overall performance of the cleaning block. These acids may further be selected to have chelating and/or building properties, which results in limescale removal.

Examples of acids which may be used in the present invention include organic and inorganic acids, preferably organic acids such as citric, maleic, oxalic, succinic and tartaric acids, more preferably citric and maleic acids. Examples of alkalis which may be used in the present invention include sodium hydroxide, potassium hydroxide, alkali metal hydroxides, alkaline earth metal hydroxides and amines, for example monoethylamine, monoethanolamine and triethanolamine .

The cleaning block of the present invention may comprise a chelating agent. Chelating agents may improve the limescale/rust removal performance of the cleaning block.

Furthermore the chelating agent may improve the stability of any bleaching agent in the formulation. Suitable chelating agents include EDTA, NTA, imido disuccinic acid salts or preferably biodegradable chelating agents, such as s,s~ ethylene diamino disuccinate and dipicolinic acid. The chelating agent may be present in an amount of 0.05 to 20 weight %, preferably 0.1 to 10 weight % based on the total weight of the block. The chelating agent may be present in an amount of 0.05 to 20 weight %, preferably 0.1 to 10 weight % based on the weight of each composition in the block.

The cleaning block may include a dispersing agent. The dispersing agent may be present in one or more of the compositions of the block. For example, the dispersing agent may be used in the first composition, the second composition and/or the further composition. The dispersing agent may be included in the first composition, second composition and/or further composition in an amount of 0.1 to 20 weight %, preferably 1 to 10 weight % based on the total weight of each composition. By varying the amount of dispersing agent in a composition, the dispersibility and/or solubility of that composition may be controlled. For example, the dispersibility/solubility of a composition may be increased by increasing the concentration of dispersing agent in the composition. The concentration of dispersing agent in the cleaning block may be 0.1 to 20 weight %, preferably 1 to 10 weight %.

Examples of dispersing agents include fόrmaldehyde-casein, colloidal silica, starch alginic acid and salts thereof, Veegum clays, sugars, gelatine, crosslinked carboxymethylcellulose (e.g., AC-Di-Sol® sold by FMC), polyvinylpyrrolidone and zeolites. Combinations of these agents may also be used.

The cleaning block may comprise an effervescent agent.

The effervescent agent may be present in one or more of the compositions of the block. Preferably, the effervescent agent is only present in certain portions of the block. Accordingly, certain compositions of the block may be devoid of effervescent agent. In one embodiment, the first composition comprises effervescent agent whilst the second composition is devoid of effervescent agent. Alternatively, the second composition comprises effervescent agent whilst the first composition is devoid of effervescent agent. The further composition (s) may also include effervescent agent.

When the effervescent agent comes into contact with water, bubbles of gas are evolved. This evolution of gas may help the cleaning block to move through the column of water. In one embodiment, bubbles of gas adhere to the surface of the cleaning block increasing its buoyancy. This causes the block to rise through the column of water. As the block reaches the surface of the water, the bubbles break, causing the block to descend through the column of water. As more bubbles collect on the block's surface, the block may rise through the column of water again. This movement may help to mix the active materials in the column of water.

The effervescent agent typically comprises an acid source and a carbonate. The evolution of gas may be a result of the reaction between the acid source and .carbonate to produce carbon dioxide gas. The acid source may be present in an amount of 0.1 to 20 weight %, preferably 0.5 to.10 weight % of the total weight of the block. Each of the compositions may include the acid source in an amount of 0.1 to 20 weight %, preferably 0.5 to 10 weight % of the total weight of each composition. The carbonate may be present in an amount of 0.1 to 50 weight %, preferably 0.5 to 10 weight % of the total weight of the block. Each of the compositions may include the carbonate in an amount of 0.1 to 50 weight %, preferably 0.5 to 10 weight % of the total weight of each composition.

Suitable carbonates include alkali and alkali earth metal carbonates and bicarbonates . Examples include carbonate and bicarbonate salts of potassium, sodium and lithium. Carbonates and bicarbonates of sodium and lithium are preferred. In a preferred embodiment, sodium carbonate and/or sodium bicarbonate are employed.

Suitable acid sources include organic acids, such as an carboxylic acids and/or amino acids. Preferably the effervescent source comprises citric acid and/or maleic acid, more preferably citric acid. The effervescent agent may also be a source of oxygen. Examples include perborates, percarbonates and solid peroxides .

The effervescent agent may be present in an amount of 0.1 to 50 weight %, preferably 0.5 to 10 weight % of the total weight of each composition. The effervescent agent may be present in an amount of 0.1 to 50 weight %, preferably 0.5 to 10 weight % of the total weight of the block.'

The cleaning block of the present invention may include a fragrance. Any suitable fragrance may be used. For example, the fragrance may be in solid or liquid form. Liquid fragrances are preferred.

The fragrance may be formed of discreet chemicals. More often, however, the fragrance will be a mixture of volatile ingredients of natural or synthetic origin. The nature of these ingredients may be determined with reference to specialized books of perfumery, such as "Perfume and Flavour Chemicals" (S. Arctander, Montclair N.J., USA 1969), "Perfumery" (Wiley-Intersciences, New York, USA 1994) or similar references. Mixtures of one or more fragrances may be employed. For example, mixtures of two or three fragrances may be employed. Examples of suitable fragrances are described in WO 2005/118007.

The fragrance may be present in an amount of 0.1 to 10 weight %, preferably 0.5 to 5 weight % of each composition.

The fragrance may be present in an amount of 0.1 to 10 weight %, preferably 0.5 to 5 weight % of the total weight of the block. Preferably, the solubility of the block is controlled to release the fragrance adjacent the surface of the column of water, so that the fragrance can be perceived by a user from above the surface of the column of water.

The cleaning bloqk may also include agents that adjust the wetting properties of the surface under treatment. Such agents may make the surface more hydrophilic or more hydrophobic. The surface may be made more hydrophilic by including agents, such as polyethylene oxide and PVP in the cleaning block. The surface may be made more hydrophobic by including silicone polymers in the cleaning block. Such agents may be included in each of the compositions in an amount of 0.001 to 10 weight %, preferably 0.01 to 5 weight %. Such agents may be included in the cleaning block in an amount of 0.001 to 10 weight %, preferably 0.01 to 5 weight

The cleaning block of the present invention may formed into a variety of different shapes and sizes. For example, the cleaning block may be substantially cylindrical or substantially cuboid in shape. Alternatively, the block may be spherical. The block may measure 1 to 20 cm across, preferably 3 to 10 cm across its largest dimension.

Where the block is cylindrical, the block may have a diameter of 1 to 10 cm, preferably 3 to 8 cm. The length of the block may be 1 to 10 cm, preferably 3 to 8 cm.

Where the block is cuboid, the block may be 1 to 10 cm, preferably 3 to 8 cm long. The block may be 1 to 10 cm, preferably 3 to 8 cm wide and 1 to 10 cm, preferably 3 to 8 cm deep.

Where the block is spherical, the block may have a diameter of 1 to 10 cm, preferably 3 to 8 cm.

In one embodiment, the first portion of the cleaning block may at least partially surround the second portion. Accordingly, the cleaning block may include an outer region comprising the first composition and an inner region comprising the second composition. At least 50% of the surface area of the inner region may be surrounded, preferably from 50% to 100%, even more preferably from 70% to 100%, and most preferably from 85% to 100%. The outer region may be the same thickness as the inner region.

Alternatively, the outer region may be thicker or thinner than the inner region. Regions formed from the first composition may alternate with regions formed from the second composition. For example, the cleaning block may be co-extruded with alternating layers of the first composition and second composition. The ratio of the first composition to the second composition may be 0.5 to 2, preferably 0.8 to 1.2. Optionally, layer (s) formed from the further composition (s) may be provided.

In a preferred embodiment, the cleaning block is in the form of a layered sphere having an outer layer comprising the first composition and an inner layer comprising the second composition. The sphere may be provided with layers of the first composition alternating with layers of the second composition. The layers may be concentric layers. Optionally, layer (s) formed from the further composition (s) may be provided.

In another embodiment, the cleaning block is in the form of a layered block. The first portion may take the form of one layer, whilst the second portion may take the form of another layer. The layers may be placed alternately on top of one another. Optionally, layer (s) formed from the further composition (s) may be provided. The layers may be of the same or of a different thickness.

In yet another embodiment, the first portion of the cleaning block is dispersed in a matrix of the second portion (and vice-versa) . Optionally, the further composition (s) may be dispersed in the matrix. Alternatively or additionally, further composition (s) may form part of the matrix.

In yet a further embodiment, at least part of the first portion and at least part of the second portion of the block form at least part of the surface of the block. For example, the first portion and the second portion may be of the form of rectangular blocks joined on one face to one another. Alternatively, one of the portions may be contained in an indentation in the other, such that part of the first portion and part of the second portion form an outer surface of the block.

According to a further aspect of the present invention there is provided a method of preparing the block described above comprising providing at least the first and the second portion, joining at least said first portion with said second portion, and optionally cutting said joined first and second portion, to form the block.

Preferably", the method of the present invention comprises extruding at least a first and a second composition to form the first and second portions said block.. Formulations for the different compositions may be extruded to form a rod or bar with is then cut into appropriately sized pieces or blocks. Suitably, the ingredients of each composition are fed into separate screw-mixer-extruders. In each mixer the ingredients are conveyed to the inside of the barrel by rotation of the screws. Each composition is then pushed outside the its respective barrel towards the compression chamber. In this chamber the different compositions can be joined to each other. For example, the different compositions can exit the extruders one inside another which is so-called axial extrusion.

Typically blocks of the present invention weigh from 20 to 150 grams, preferably from 30 to 50 grams.

As mentioned above, the cleaning blocks of the present invention may be used to form an aqueous hard surface cleaning composition. Specifically, the cleaning blocks of the present invention are intended to be placed in a column of water. Upon addition to a column of water, at least part of the first portion of the block disperses and/or dissolves. As the first portion is of a different density to the second portion of the block, the block moves up or down the column of water depending on the density of the first portion relative to the second portion. Where the first portion has a lower density than the second portion, the block moves down the column of water as the first portion dissolves or disperses. In contrast, where the first portion has a higher density than the second portion, the block moves up the column of water as the first portion dissolves or disperses. The configuration and/or position of each of the portions within the cleaning block may have an affect on the buoyancy of the cleaning block in water. Accordingly, it may be possible to control the movement of the block • up and/or down column of water by varying the configuration and/or position of the respective portions within the cleaning block. In a preferred embodiment, the block moves up and down the column of water as it disperses and/or dissolves. The block may move up and down the column in a number of cycles for example 1 to 100 cycles.

Claims

1. A cleaning block comprising at least a first portion and a second portion, said portions having different bulk densities, wherein, upon addition of the block to a column of water, at least part of the first portion disperses and/or dissolves such that the block moves up or down the column of water.

2. The block according to claim 1 wherein the second portion at least partially disperses and/or dissolves in water.

3. The block according to claim 2 wherein the first portion disperses and/or dissolves in water at a different rate from that of the second portion.

4. The block according to any one of the preceding claims wherein the first portion comprises a dispersing agent and/or an effervescent agent.

5. The block according to any one of the preceding claims wherein the first and/or the second portion is formed from an aerated composition. . ^■

6. The block according to any one of the preceding claims wherein, upon addition of the block to a column of water, the block floats and subsequently, when at least part of the first portion has dispersed and/or dissolved in the water, the block moves down the column of water.

7. The block according to claim 6 wherein the block subsequently" moves up the column of water.

8. The block according to any one of claims 1 to.5 wherein, upon addition of the block to a column of water, the block sinks and subsequently, when at least part of the first portion has dispersed and/or dissolved in the water, the block moves up the column of water.

9. The block according to claim 8 wherein the block subsequently moves down the column of water.

10. The block according to any one of the preceding claims comprising an anti-limescale agent, fragrance, enzyme and/or detergent .

11. The block according to claim 10 comprising an anti- limescale agent or a fragrance which is at least partially released towards the top of the column of water.

12. The block according to claim 10 comprising an enzyme or a detergent which is at least partially released towards the bottom of the column of water.

13. The block according to any one of the preceding claims wherein, upon addition of the block to a column of water, -at least part of the first portion disperses and/or dissolves such that the first portion substantially separates from the second composition.

14. The block according to claim 13 wherein the first composition moves towards the top of the column of water and the second portion moves towards the bottom of the column of water.

15. The block according to any one of claims 1 to 12 wherein the block is in the form of a layered sphere, wherein the first portion is an outer layer comprising a first composition 'and the second portion is an inner layer comprising a second composition.

16. The block according to any one of claims 1 to 12 wherein at least part of the first portion and at least part of the second portion form at least part of the surface of the block.

17.. The block according to any one of the preceding claims which is a lavatory cleaning block.

18. A method of preparing the block as defined in any one of claims 1 to 17 comprising providing at least the first and the second portion, joining at least said first portion with said second portion, and optionally cutting said joined first and second portion, to form the block.

19. The method according to claim 18 comprising extruding at least a first and a second composition to form said block.