Patent Description:
Unit dose cleaning compositions such as detergent tablets are one of the most consumer preferred products, due to ease of handling, dosage and storage. Such compositions are used to clean surfaces, such as bathroom surfaces, kitchen surfaces as well as to clean laundry surfaces.

There have been many attempts to formulate unit dose cleaning compositions which are resistant to breakage (to withstand transport, accidental drop etc) yet dissolve quickly. However, a dichotomy exists in that as compression force is increased in an attempt to provide a composition that is resistant to breakage, the rate of dissolution of the tablets becomes slower. A low compression force, on the other hand, improves dissolution but at the expense of tablet strength. This problem is compounded by the fact that conventional tablet compositions have relatively poor long-term storage-stability characteristics and, to compensate, have to be manufactured to a higher compression specification.

Attempts to provide unit dose cleaning composition with acceptable strength and dissolvability have been described in the prior art. For example, <CIT> discloses a detergent tablet for use in a washing machine, the tablet having one or more phases at least one of which is in the form of a compressed particulate solid comprising: a) a polymeric disintegrant having a particle size distribution such that at least <NUM> % by weight thereof has a particle size below about <NUM> and at least <NUM> % by weight thereof has a particle size below about <NUM>; and b) a water-soluble hydrated salt having a solubility in distilled water of at least about <NUM>/<NUM> at <NUM>.

However, the detergent tablets of <CIT> still suffer from poor dissolvability when added to a bowl of water meaning that the detergent tablets do not meet consumer expectations, in particular in washing laundry.

<CIT> discloses cellulose disintegrant for detergent compositions.

<CIT> discloses washing and cleaning agent shaped bodies which, as preparation components, contain substances selected from the group of alkali sulfates and/or alkaline-earth sulfates and/or alkaline-earth carbonates and/or alkaline-earth phosphates and/or alkaline-earth citrates. These shaped bodies are said to comprise advantageous properties with regard to application techniques if at least <NUM> weight percent of the designated alkali salts and/or alkaline-earth salts comprise particle sizes greater than <NUM> micrometers.

<CIT>) discloses a tablet of compacted particulate detergent composition comprising non-soap surfactant and detergency builder, and; a) disintegration-promoting particles comprising water-insoluble disintegrant which can swell to at least twice its volume on contact with water, and a water-absorbent carrier which so swells to a lesser extent, and b) water-soluble polymeric binder solid at <NUM> degrees centigrade, and either c) comprising <NUM> to <NUM> percent wt. of water-soluble disintegration-promoting particles comprising at least <NUM> percent of materials selected from; compounds with water solubility at <NUM> degrees centigrade of at least <NUM> grams per <NUM> grams of water phase I sodium tripolyphosphate sodium tripolyphosphate that contains water of hydration in an amount which is at least <NUM> percent wt. of the sodium tripolyphosphate in the particles, or d) having a diametral fracture stress of at least <NUM> kPa. The tablets are said to exhibit good disintegration properties.

<CIT>) discloses a disinfecting tablet is disclosed having rapid disintegration and low friability. In one embodiment, the disinfecting tablet comprises sodium dichloro isocyanurate dihydrate and at least one swellable disintegrating agent assisting with rapid disintegration of the tablet. Also disclosed are a disinfecting cleaning tool assembly and a method of cleaning.

<CIT>) discloses peroxygen bleaches, especially diperazelaic acid, are provided in tablet form useful for bleaching fabrics. <CIT> discloses laundry detergent tablets comprising an ion exchange resin and a further disintegrant selected from the group consisting of: celluloses and derivatives thereof; microcrystalline cellulose; and mixtures thereof.

<CIT> discloses a tablet comprising an effervescent system formed by a water-soluble organic acid and an inorganic salt selected from the group formed by an alkaline carbonate, an alkaline bicarbonate, and mixtures thereof; and a disintegrating agent comprising a combination of at least two disintegrating agents selected from the group formed by starch, pregelatinized starch, sodium starch glycolate, and sodium carboxymethyl cellulose, and urea.

It is therefore an object of the invention to provide unit dose tablet compositions having improved dissolution characteristics and which at the same time delivers excellent storage stability in terms of strength.

Accordingly, and in a first aspect, there is provided a unit-dose tablet composition comprising:.

In a second aspect the present invention, provides a process for preparing a unit dose tablet composition, comprising the steps of:.

Wherein the step b) is carried out at pressure in the range of <NUM> to <NUM> kgf/cm<NUM>.

In a third aspect the present invention provides a method of cleaning a surface comprising the step of dissolving a unit-dose tablet composition as defined herein in water to provide a solution of the cleaning composition, and contacting the surface with the cleaning composition, preferably wherein the surface is a hard surface, a soft surface or a laundry surface.

In a fourth aspect the present invention provides a use of a unit-dose tablet composition as defined herein for cleaning a surface, preferably wherein the surface is a hard surface, a soft surface or a laundry surface.

These and other aspects, features and advantages will become apparent to those of ordinary skill in the art from a reading of the following detailed description and the appended claims. For the avoidance of doubt, any feature of one aspect of the present invention may be utilised in any other aspect of the invention. The word "comprising" is intended to mean "including" but not necessarily "consisting of" or "composed of. " In other words, the listed steps or options need not be exhaustive. It is noted that the examples given in the description below are intended to clarify the invention and are not intended to limit the invention to those examples per se. Except in the operating and comparative examples, or where otherwise explicitly indicated, all numbers in this description indicating amounts of material or conditions of reaction, physical properties of materials and/or use are to be understood as modified by the word "about". Numerical ranges expressed in the format "from x to y" are understood to include x and y. When for a specific feature multiple preferred ranges are described in the format "from x to y", it is understood that all ranges combining the different endpoints are also contemplated.

The unit dose tablet composition comprises a swellable disintegrant and a non-swellable disintegrant. A swellable disintegrant is one which has a water absorption ratio (WAR) of greater than <NUM> and a non-water swellable disintegrant is one which has a water absorption ratio of less than <NUM>.

Water Absorption Ratio is a measure as to how much water a material absorbs under controlled and defined conditions. The process described in ASTM D570 is used in this application.

The swellable disintegrant is selected from microcrystalline cellulose, sodium starch glycolate and mixtures thereof. Preferably, the swellable disintegrant comprises from <NUM> to <NUM>% wt. of the unit dose tablet composition, more preferably from <NUM> to <NUM>% wt. and most preferably from <NUM> to <NUM>% wt.

The non-swellable disintegrant is selected from polyvinyl pyrrolidone, calcium silicate, starch, magnesium stearate and mixtures thereof. Preferably, the non-swellable disintegrant comprises from <NUM> to <NUM>% wt. of the unit dose tablet composition, more preferably from <NUM> to <NUM>% wt. and most preferably from <NUM> to <NUM>% wt.

Preferably, the water-soluble salt has a solubility of at least <NUM>/<NUM> at <NUM>, preferably at least <NUM>/<NUM>, more preferably at least <NUM>/<NUM>, and most preferably at least <NUM>/<NUM> at <NUM>. Preferably, the water-soluble salt has a solubility of at most <NUM>/<NUM>, more preferably at most <NUM>/<NUM> at <NUM>, even more preferably at most <NUM>/<NUM>.

In other words, the water-soluble salt has a solubility of in the range of <NUM>/<NUM> to <NUM>/<NUM> at <NUM>, preferably <NUM>/<NUM> to <NUM> /<NUM> at <NUM>, more preferably <NUM>/<NUM> to <NUM>/<NUM> at <NUM>, even more preferably <NUM>/<NUM> to <NUM>/<NUM>.

The composition preferably comprises a water-soluble salt that is selected from anhydrous forms or hydrates of salts of mono or divalent alkali metals, preferably anhydrous forms or hydrates of salts of mono alkali metals, more preferably wherein the mono alkali metals is sodium or potassium.

Preferably, the anhydrous forms or hydrates of salts of mono alkali metals is selected from the group consisting of sodium chloride, sodium sulphate, sodium hydrogen carbonate, potassium chloride, potassium sulphate, potassium hydrogen carbonate and mixtures thereof.

The unit-dose tablet composition preferably comprises <NUM> to <NUM> wt. % water soluble salt, preferably <NUM> to <NUM> wt. %, more preferably <NUM> to <NUM> wt.

The composition comprises an effervescent. Suitable effervescents include organic acids such as citric acid, tartaric acid, fumaric acid, malic acid, adipic acid, succinic acid, and a carbonate salt. Preferred carbonate salts include sodium carbonate, potassium carbonate, calcium carbonate, sodium bicarbonate, potassium bicarbonate, calcium carbonate, calcium bicarbonate and magnesium carbonate as well as mixtures thereof.

The level of effervescent is from <NUM> to <NUM>% wt. of the composition, more preferably from <NUM> to <NUM>% wt. of the composition.

Typically, tablets comprise high amounts of filler however, we have found that this level may be significantly reduced thanks to the discovery that the claimed combination of disintegrants improve disintegration without such high levels of fillers.

The composition is also advantageous in that it requires less filler than typical tablet dose compositions.

Preferably, the unit dose cleaning composition comprises no more than <NUM>% filler, more preferably no more than <NUM>% wt. and most preferably no more than <NUM>% filler.

Preferably, the composition comprises some filler though and this should be at least <NUM>% wt. of the composition.

Fillers suitable for use in the composition include calcium carbonate, zeolite, clays such as bentonite, dolomite and combinations thereof.

The unit-dose tablet composition preferably has a diametral fracture stress (DFS) ratio of DFSair/DFSwater of at least <NUM>, preferably at least <NUM>, preferably at least <NUM> more preferably at least <NUM>.

More preferably, the unit-dose cleaning composition has a diametral fracture stress (DFS) ratio of DFSair/DFSwater in the range of <NUM> to <NUM>, preferably <NUM> to <NUM>.

The DFSair/DFSwater ratio can be measured using techniques known to the skilled person. The DFS can be measured using a texture analyser, for example a CT3 Brookfield Texture Analyser. For examples, the DFSair/DFSwater can be measured using a TA instrument, model TA-XT2i and the Texture Experte software (Texture Technologies Corp. , Scarsdale, NY, USA/- Stable Micro Systems, Surrey, England, UK). The instrument is calibrated with a <NUM> load cell and fitted with a stainless steel flat-bottomed cylindrical probe with <NUM><NUM> surface area (Kobe probe). The methodology consists in positioning the tablet to the flat surface of the probe. The probe moves until a trigger force is detected at which point the TA is set to maintain a predetermined nominal force for a given period of time (<NUM> sec). As the tablet starts disintegrating, the TA measures the penetration distance as the tablet is compressed while submerged in the medium (water). A constant temperature of the medium of <NUM> is maintained during the tests by means of a thermos stated double wall cell and a heating bath/circulator (Haake, Karlsruhe, Germany).

Typically, the unit-dose tablet composition comprises <NUM> to <NUM> wt. % surfactant system selected from anionic surfactants, cationic surfactants, non-ionic surfactants, amphoteric surfactants.

The unit dose tablet composition of the invention preferably comprises an anionic surfactant or a mixture of anionic surfactants. Anionic surfactants are included in the composition for primary cleaning action by emulsifying the oil attached to the substrate. Any non-soap anionic surfactant known in the art for use in laundry detergents may be used herein. In general, these surfactants are described in well-known textbooks like "<NPL>, <NPL>, and/or the current edition of "<NPL> or in "<NPL>.

A suitable class of anionic surfactants are water-soluble salts, particularly alkali metal (e.g., sodium or potassium), ammonium and alkylolammonium salts of organic sulphuric acid monoesters and sulphonic acids having in the molecular structure a branched or straight chain alkyl group and condensations products thereof containing <NUM> to <NUM> carbon atoms or an alkyl-aryl group containing <NUM> to <NUM> carbon atoms in the alkyl part.

Preferred anionic surfactants include higher alkyl aromatic sulphonates such as higher alkyl benzene sulphonates containing from <NUM> to <NUM> carbon atoms in the alkyl group in a straight or branched chain, particular examples of which are higher alkyl benzene sulphonates or of higher-alkyl toluene, xylene or phenol sulphonates, alkyl naphthalene sulphonates, diamyl naphthalene sulphonate, and dinonyl naphthalene sulphonate; alkyl sulphates containing <NUM> to <NUM> carbon atoms and alkyl ether sulphates containing from <NUM> to <NUM> ethylene oxide or propylene oxide, preferably <NUM> to <NUM> ethylene oxide units per molecule.

Non-limiting examples of the anionic surfactants include any of the common anionic surfactants such as linear or modified, e. branched alkylbenzene sulphonates, alkylpoly(ethoxylates), sodium lauryl ether sulphates, methyl ester sulphonates, primary alkyl sulphates or mixtures thereof.

The non-soap anionic surfactant is present in the detergent composition in a concentration of <NUM> to <NUM>%, preferably not less than <NUM>%, more preferably not less than <NUM>%, still more preferably not less than <NUM>% but typically not more than <NUM>%, preferably not more than <NUM>% or even not more than <NUM>% by weight of the total composition.

Anionic surfactant of the present invention may be combined with another surfactant generally chosen from non-ionic, cationic, amphoteric or zwitterionic surfactants.

In view of the anionic character of the anionic surfactant, cationic, amphoteric or zwitterionic surfactants when added are added at concentrations that do not hinder the performance of the composition.

Suitable non-ionic surfactants include water soluble aliphatic ethoxylated nonionic surfactants commercially known, including the primary aliphatic alcohol ethoxylates and secondary aliphatic alcohol ethoxylates. This includes the condensation products of a higher alcohol (e.g., an alkanol containing about <NUM> to <NUM> carbon atoms in a straight or branched chain configuration) condensed with about <NUM> to <NUM> moles of ethylene oxide, for example, lauryl or myristyl alcohol condensed with about <NUM> moles of ethylene oxide (EO), tridecanol condensed with about <NUM> to <NUM> moles of EO, myristyl alcohol condensed with about <NUM> moles of EO per mole of myristyl alcohol, the condensation product of EO with a cut of coconut fatty alcohol containing a mixture of fatty alcohols with alkyl chains varying from <NUM> to about <NUM> carbon atoms in length and wherein the condensate contains either about <NUM> moles of EO per mole of total alcohol or about <NUM> moles of EO per mole of alcohol and tallow alcohol ethoxylates containing <NUM> EO to <NUM><NUM> EO per mole of alcohol.

Examples of the foregoing non-ionic surfactants include, but are not limited to, the Neodol (trade mark, ex Shell) ethoxylates, which are higher aliphatic, primary alcohol containing about <NUM> to <NUM> carbon atoms, such as C9 to C11 alkanol condensed with <NUM> to <NUM> moles of ethylene oxide (Neodol <NUM>-<NUM> or Neodol <NUM>-<NUM>), C12-<NUM> alkanol condensed with <NUM> moles ethylene oxide (Neodol <NUM>-<NUM>), C12-<NUM> alkanol condensed with <NUM> moles ethylene oxide (Neodol <NUM>-<NUM>), C14-<NUM> alkanol condensed with <NUM> moles ethylene oxide (Neodol <NUM>-<NUM>), and the like. Such ethoxamers have an HLB (hydrophobic lipophilic balance) value of about <NUM> to <NUM> and give good O/W emulsification, whereas ethoxamers with HLB values below <NUM> contain less than <NUM> ethyleneoxide groups and tend to be poor emulsifiers and poor detergents.

Suitable amphoteric surfactants include derivatives of aliphatic secondary and tertiary amines containing an alkyl group of <NUM> to <NUM> carbon atoms and an aliphatic radical substituted by an anionic water-solubilizing group, such as sodium <NUM>-dodecylamino- propionate, sodium <NUM>-dodecylaminopropane sulphonate and sodium N-<NUM>-hydroxydodecyl-N-methyltaurate.

Suitable cationic surfactants are quaternary ammonium salts according to the present invention are quaternary ammonium salts characterised in that the ammonium salt has the general formula: R1R2R3R4N+X- wherein R1 is a C12 to C18 alkyl group, each of R2, R3 and R4 independently is a C1 to C3 alkyl group and X is an inorganic anion. R1 is preferably a C14 to C16 straight chain alkyl group, more preferably C16. R2, R3 and R4 are preferably methyl groups. The inorganic anion (X-) is preferably chosen from halide, sulphate, bisulphate or hydroxide.

For the purposes of this invention, a quaternary ammonium hydroxide is considered to be a quaternary ammonium salt. More preferably the anion is a halide ion or sulphate, most preferably a chloride or sulphate. Cetyl-trimethylammonium chloride is a specific example of a suitable compound and commercially abundantly available.

Another type of quaternary ammonium cationic surfactant is the class of benzalkonium halides, also known as alkyldimethylbenzylammonium halides. The most common type being benzalkonium chloride, also known as alkyldimethylbenzylammonium chloride (or ADBAC).

Suitable zwitterionic surfactants include derivatives of aliphatic quaternary ammonium, sulphonium and phosphonium compounds having an aliphatic radical of from <NUM> to <NUM> carbon atoms and an aliphatic radical substituted by an anionic water-solubilising group, for instance <NUM>-(N-N-dimethyl-N-hexadecylammonium) propane-<NUM> -sulphonate betaine, <NUM>-(dodecylmethyl sulphonium) propane-<NUM> -sulphonate betaine and <NUM>- (cetylmethylphosphonium) ethane sulphonate betaine.

The unit-dose tablet composition is preferably a shaped solid, preferably the unit dose shaped solid is a tablet, lozenge, block or cube.

The composition may be used in washing machines, dishwashers, in toilet bowls, cisterns, water tanks, washing up bowls, surface cleaning and personal care applications.

Wherein the step b) is carried out at pressure in the range of <NUM> to <NUM> kgf/cm<NUM>, more preferably <NUM> to <NUM> kgf/cm<NUM>.

Preferably, step i) also includes adding a builder and a filler.

The amounts and ingredients described above for the unit-dose tablet composition apply mutatis mutandis to the method of preparing the unit-dose tablet composition.

In a third aspect, the present invention relates to a method of cleaning a surface comprising the step of dissolving a unit-dose tablet composition as defined herein in water to provide a solution of the cleaning composition and contacting a surface with the cleaning composition.

Preferably, the method of cleaning a surface comprising the step of dissolving a unit-dose tablet composition as defined herein in water, to provide a solution of the cleaning composition, and contacting a surface with the cleaning solution of the cleaning composition, preferably wherein the surface is a hard surface, a soft surface or a laundry surface.

The surface to be cleaned is preferably selected from the group of hard, soft and laundry surfaces.

Preferably, surface is a hard surface. The hard surface is preferably selected from a bathroom, kitchen or floor surface. Preferably the bathroom surface is selected from the group consisting of baths, toilet bowls, toilet cisterns, shower surfaces, floors and tiles. Preferably, the hard surface is a kitchen surface selected from the group of dishware, worktops, cooker tops, floors, ovens and sinks. The floor surface may be any stone, linoleum, tile, wood, laminate floor.

Preferably, the surface is a soft surface. Preferably the soft surface is selected from the skin and/or scalp. For example, the unit dose composition is preferably dissolved in a container of water for washing the body, hair etc. In other words, the unit dose compositions may be used for personal care applications.

Preferably, the surface is a laundry surface. The laundry surface is preferably any fabric surface to be laundered. A fabric surface is, for example, clothes, towels, linen, bedding etc..

Preferably, the method of cleaning a surface comprises the step of dissolving a unit-dose cleaning composition as defined herein in water to provide a solution of the cleaning composition and contacting a surface with the cleaning composition wherein the surface is a laundry surface.

Preferably, the unit-dose tablet composition is added to a container of water to be used in the cleaning of hard, soft and laundry surfaces.

Preferably the unit dose tablet composition is dosed in a bottle containing sufficient amount of water, thereby provides a cleaning composition in the bottle. The bottle may be equipped with a spray trigger or foaming engine. Thus, a consumer may dispense the cleaning composition directly on a surface as foam or spray. Preferably the ratio of the composition to the water is in the range from <NUM>:<NUM> to <NUM>:<NUM>, more preferably from <NUM>:<NUM> to <NUM>:<NUM> and most preferably from <NUM>:<NUM> to <NUM>:<NUM> by wt.

Preferably, the unit-dose tablet composition is added to a washing machine or a container of water to be used in laundering of fabrics.

In a fourth aspect, the present invention relates to the use of a unit-dose tablet composition as defined herein for cleaning a surface, wherein the surface is a hard surface, a soft surface or a laundry surface.

Unit-dose tablet compositions were prepared according to Table <NUM>. The water-soluble salt and disintegrant is post dosed to the remaining ingredients.

Claim 1:
A unit-dose tablet composition comprising:
a) a swellable disintegrant selected from microcrystalline cellulose, sodium starch glycolate and mixtures thereof;
b) a non-swellable disintegrant, selected from polyvinyl pyrrolidone, calcium silicate, starch, magnesium stearate and mixtures thereof;
c) a water-soluble salt having a solubility in distilled water of in the range of <NUM>/<NUM> to <NUM>/<NUM> at <NUM>;
d) an effervescent; and
e) a surfactant.
wherein the swellable disintegrant has a water absorption ratio of greater than <NUM> and the non-swellable disintegrant has a water absorption ratio of less than <NUM> when measured using the ASTM D570 method.