Classifications

• • C—CHEMISTRY; METALLURGY
  • C11—ANIMAL OR VEGETABLE OILS, FATS, FATTY SUBSTANCES OR WAXES; FATTY ACIDS THEREFROM; DETERGENTS; CANDLES
  • C11D—DETERGENT COMPOSITIONS; USE OF SINGLE SUBSTANCES AS DETERGENTS; SOAP OR SOAP-MAKING; RESIN SOAPS; RECOVERY OF GLYCEROL
  • C11D3/00—Other compounding ingredients of detergent compositions covered in group C11D1/00
  • C11D3/02—Inorganic compounds ; Elemental compounds
  • C11D3/12—Water-insoluble compounds
  • C11D3/124—Silicon containing, e.g. silica, silex, quartz or glass beads
  • C11D3/1246—Silicates, e.g. diatomaceous earth
  • C11D3/1253—Layer silicates, e.g. talcum, kaolin, clay, bentonite, smectite, montmorillonite, hectorite or attapulgite
  • C11D3/126—Layer silicates, e.g. talcum, kaolin, clay, bentonite, smectite, montmorillonite, hectorite or attapulgite in solid compositions
• • C—CHEMISTRY; METALLURGY
  • C11—ANIMAL OR VEGETABLE OILS, FATS, FATTY SUBSTANCES OR WAXES; FATTY ACIDS THEREFROM; DETERGENTS; CANDLES
  • C11D—DETERGENT COMPOSITIONS; USE OF SINGLE SUBSTANCES AS DETERGENTS; SOAP OR SOAP-MAKING; RESIN SOAPS; RECOVERY OF GLYCEROL
  • C11D17/00—Detergent materials or soaps characterised by their shape or physical properties
  • C11D17/0047—Detergents in the form of bars or tablets
  • C11D17/0065—Solid detergents containing builders
  • C11D17/0073—Tablets
• • C—CHEMISTRY; METALLURGY
  • C11—ANIMAL OR VEGETABLE OILS, FATS, FATTY SUBSTANCES OR WAXES; FATTY ACIDS THEREFROM; DETERGENTS; CANDLES
  • C11D—DETERGENT COMPOSITIONS; USE OF SINGLE SUBSTANCES AS DETERGENTS; SOAP OR SOAP-MAKING; RESIN SOAPS; RECOVERY OF GLYCEROL
  • C11D17/00—Detergent materials or soaps characterised by their shape or physical properties
  • C11D17/0047—Detergents in the form of bars or tablets
  • C11D17/0065—Solid detergents containing builders
  • C11D17/0073—Tablets
  • C11D17/0078—Multilayered tablets
• • C—CHEMISTRY; METALLURGY
  • C11—ANIMAL OR VEGETABLE OILS, FATS, FATTY SUBSTANCES OR WAXES; FATTY ACIDS THEREFROM; DETERGENTS; CANDLES
  • C11D—DETERGENT COMPOSITIONS; USE OF SINGLE SUBSTANCES AS DETERGENTS; SOAP OR SOAP-MAKING; RESIN SOAPS; RECOVERY OF GLYCEROL
  • C11D3/00—Other compounding ingredients of detergent compositions covered in group C11D1/00
  • C11D3/02—Inorganic compounds ; Elemental compounds
  • C11D3/12—Water-insoluble compounds
  • C11D3/124—Silicon containing, e.g. silica, silex, quartz or glass beads
  • C11D3/1246—Silicates, e.g. diatomaceous earth
  • C11D3/128—Aluminium silicates, e.g. zeolites
• • C—CHEMISTRY; METALLURGY
  • C11—ANIMAL OR VEGETABLE OILS, FATS, FATTY SUBSTANCES OR WAXES; FATTY ACIDS THEREFROM; DETERGENTS; CANDLES
  • C11D—DETERGENT COMPOSITIONS; USE OF SINGLE SUBSTANCES AS DETERGENTS; SOAP OR SOAP-MAKING; RESIN SOAPS; RECOVERY OF GLYCEROL
  • C11D3/00—Other compounding ingredients of detergent compositions covered in group C11D1/00
  • C11D3/16—Organic compounds
  • C11D3/20—Organic compounds containing oxygen
  • C11D3/22—Carbohydrates or derivatives thereof
  • C11D3/222—Natural or synthetic polysaccharides, e.g. cellulose, starch, gum, alginic acid or cyclodextrin

Definitions

• the present invention relates to cleaning compositions in the form of tablets. These tablets are intended to disintegrate when placed in water and thus are intended to be consumed in a single use.
• the tablets may be suitable for use in machine dishwashing, the washing of fabrics or other cleaning tasks.
• Products in tablet form have several advantages over powdered products: for example, they do not require measuring and are thus easier to handle and dispense into the wash-load, and they are more compact, hence facilitating more economical storage.
• Detergent compositions in tablet form and intended for fabric washing have been described in a number of patent documents including, for example GB 911 204, EP-A-711827, WO-98/42817, US 5 360 567 and WO-99/20730 (all Unilever) , US 3 953 350 (Kao) , DE 19 637 606 (Henkel) and are now sold commercially. Tablets of composition suitable for machine dishwashing have been disclosed in EP-A-318204, O96/23530 and US-A-5691293 and are sold commercially.
• Tablets of a cleaning composition are generally made by compressing or compacting a composition in particulate form. Although it is desirable that tablets have adequate strength when dry, yet disperse and dissolve quickly when brought into contact with water, it can be difficult to obtain both properties together. Tablets formed using a low compaction pressure tend to crumble and disintegrate on handling and packing; while more forcefully compacted tablets may be sufficiently cohesive but then fail to disintegrate or disperse to an adequate extent in the wash. Tabletting will often be carried out with enough pressure to achieve a compromise between these desirable but antagonistic properties. However, it remains desirable to improve one or other of these properties without detriment to the other so as to improve the overall compromise between them. US-A-3 018 267 (Procter & Gamble) taught that the force, and hence pressure, applied when compacting a composition into tablets should be limited, or else the tablets would take too long to dissolve.
• a tablet contains organic surfactant, this can function as a binder, plasticising the tablet. However, it can also retard disintegration of the tablet by forming a viscous gel when the tablet comes into contact with water. Thus, the presence of surfactant can make it more difficult to achieve both good strength and speed of disintegration: the problem has proved especially acute with tablets formed by compressing powders containing surfactant and built with insoluble detergency builder such as sodium aluminosilicate (zeolite) .
• insoluble detergency builder such as sodium aluminosilicate (zeolite)
• Such documents include O98/40462 (Rettenmaier) , 098/55583 (Unilever) and WO-98/40463 (Henkel) .
• Typical water-swellable agents which have been disclosed as possible tablet disintegrating agents are starches, cellulose and cellulose derivatives, alginates, dextrans, cross-linked polyvinyl pyrrolidones, gelatines and formaldehyde casein as well as a wide variety of clay minerals and certain ion- exchange resins.
• W098/55575 and DE 199 01 063 (both Henkel) teach the use of cellulose disintegrating aids with a particle size of less than 100 um to minimise deposition.
• the cellulose material is mixed with a material of a given oil absorbing capacity, which includes some zeolites.
• a cleaning composition in the form of a tablet which addresses one of more of the aforementioned problems can be obtained if disintegrant granules comprising a co-granulated mixture of a swelling clay, a water insoluble inorganic material and a water-swellable agent are added to the cleaning composition before it is formed into a tablet. This has been found to result in acceptably low levels of residues on the substrate being treated with the tablet and/or with the tablets maintaining good disintegration properties upon storage.
• JP 10110199 discloses detergent tablets comprising porous silica and kaolinate clay material as separately added ingredients.
• the present -invention provides a tablet of compacted particulate detergent composition comprising non-soap surfactant and detergency builder, wherein the tablet or a discrete region thereof comprises disintegrant granules comprising a water-swelling clay, a water-insoluble inorganic material and a water swellable agent.
• Particularly preferred water insoluble inorganic materials are silica or crystalline aluminosilicates.
• An especially preferred embodiment of the present invention is a tablet of compacted particulate detergent composition comprising non-soap surfactant and detergency builder, wherein the tablet or a discrete region thereof comprises disintegrant granules comprising a water-swelling clay, a water insoluble inorganic material and a water-swellable agent which in its anhydrous state, comprises no more than 20% by weight of the combined weight of the water-swelling clay, the water-insoluble inorganic material and the water-swellable agent.
• the present invention also provides a process for making a tablet of compacted particulate detergent composition comprising non-soap surfactant and detergency builder, the process comprising mixing disintegrant granules comprising a water-swelling clay, a water-insoluble inorganic material and a water swellable agent with the other constituents of the detergent composition to produce a particulate detergent composition, placing a quantity of the resultant particulate detergent composition within a mould, and, compacting the composition within the mould to produce the tablet.
• a disintegrant granule which is formed by the co-granulation of a water-swelling clay, a water insoluble inorganic material and a water swellable agent in a detergent tablet comprising non-soap surfactant and detergency builder, surprisingly good disintegration after storage of the tablets and/or acceptable residue on a substrate is obtained. It is believed that when the water-swelling clay, water insoluble inorganic material and water swellable agent are used in this co-granulated form it is much more efficient in aiding disintegration of the tablet than when the components are added separately to the composition.
• a tablet of the present invention may be either homogeneous or heterogeneous.
• ⁇ homogeneous is used to mean a tablet produced by compaction of a single particulate composition, but does not imply that all the particles of that composition will be of identical composition.
• heterogeneous is used to mean a tablet consisting of a plurality of discrete regions, for example layers, inserts or coatings, each derived by compaction from a particulate composition.
• each discrete region of the tablet will preferably have a mass of at least 5g.
• a detergent (cleaning) tablet of compacted particulate detergent composition comprising non-soap surfactant and detergency builder material according to the invention comprises a disintegrant in the form of granules, said disintegrant granules comprising a swelling clay, a water insoluble inorganic material and a water swellable agent.
• water-insoluble in relation to the inorganic material, is meant a compound with a solubility in water at 25°C of less than 5 grams per 100 grams of water, preferably less than 1 gram per 100 grams of water.
• swelling clays A number of clays are known as swelling clays.
• the term "swelling” as used herein relates to the ability of the layered clay structure to swell or expand on contact with water, that is, the particle size of a clay particle increases significantly on contact with water.
• Swelling clays which are particularly suitable for use in this invention include three- layer swelling clays which are materials classified geologically as smectites.
• smectite clays There are two distinct classes of smectite clays. In the first, aluminium oxide is present in the silicate crystal lattice; in the second class, magnesium oxide is present in the silicate crystal lattice.
• the general formulae of these smectites are Al 2 (Si 2 0 5 ) 2 (OH) 2 and Mg 3 (Si 2 0 5 ) (OH) 2 for the aluminium and magnesium oxide type clay respectively.
• the range of the water of hydration in the clay can vary with the processing to which it has been subjected. Such processing does not significantly affect the swelling characteristics of the hydrated clays as this is dictated by the silicate lattice structure. Furthermore, atom substitution by iron and magnesium can occur within the crystal lattice of the smectites, while metal cations such as Na + , Ca 2+ , as well as H + , can be co- present in the water of hydration to provide electrical neutrality.
• the three-layer, swelling alumino silicates clays useful in the invention are further characterised by a dioctahedral crystal lattice, while the swelling three-layer magnesium silicates have a trioctahedral crystal lattice.
• the clays employed in the invention can contain cationic counterions such as protons, sodium ions, potassium ions, calcium ions and magnesium ions. It is customary to distinguish between clays on the basis of one cation predominantly or exclusively absorbed. For example, a sodium clay is one in which the absorbed cation is predominantly sodium. Such absorbed cations can become involved in exchange reactions with cations present in aqueous solutions.
• Particularly suitable smectite clays include montmorillonite and hectorite clays.
• montmorillonite clays One class of naturally-occurring montmorillonite clays is known as the bentonite clays and these have been found to be especially useful in the present invention.
• Different forms of bentonite clays are known in which the inherent negative charge of the clay matrix is balanced by different cations.
• the naturally-occurring forms where the cation is predominantly either sodium (sodium clay) or calcium (calcium clay) are suitable, as is the material produced by treating calcium bentonite with a compound of sodium and with other cations .
• the smectite clays used in the present invention are commercially available. Such clays include in addition to those mentioned hereinabove, saponite, volchonskoite, nontronite and sauconite. Suitable clays are available under various trade names such as GELWHITETM GP, Bentonite L, H and MB all from Southern Clay,USA; clays available under the tradename VOLCAYTM from American Colloid Co., USA. Other suitable clays are available commercially.
• the smectite minerals obtained under these commercial and trade names can comprise mixtures of the various discrete mineral entities. Such mixtures of the smectite minerals are suitable for use in the invention.
• a preferred bentonite clay is a calcium-form bentonite clay which has been treated with a sodium compound.
• a calcium-form bentonite clay which has been treated with sodium carbonate and which is sold under the trade names BREBENTTM and FLUGELTM (ex Laporte PLC) .
• the weight mean particle size of these clays is between 5 and 25 microns when measured by Malvern Mastersizer using the method described hereinbelow.
• These clays contain relatively high levels of sodium for what is termed a "calcium-form" clay. Calcium form clays have been found to be especially suitable according to the present invention.
• the weight mean particle size of the materials used in this invention is determined using a Malvern Mastersizer model X, with a lens range of up to 300 mm RF and MS17 sample presentation unit.
• This instrument made by Malvern Instruments, Malvern, England, uses the principle of Mie scattering, using a low power HE/NE laser. Before measurement the sample is initially dispersed ultrasonically in water for seven minutes to form am aqueous suspension. This suspension is stirred before it is subjected to the measurement procedure outlined in the instruction manual for the instrument utilising the 300 mm RF lens in the detector system.
• the Malvern Mastersizer measures the weight particle size distribution of the inorganic or reference material .
• the weight mean particle size (d 50 ) or 50 percentile is readily obtained from the data generated by the instrument .
• Smectite clays of a neutral or white colour are preferred for forming the disintegrant granule, especially for neutrally coloured detergent tablets.
• Clays having a Na 2 0 content of less than about 4% by weight and a Ca 2 0 content of less than about 1.5% by weight have been found to be effective according to the present invention.
• Suitable water-insoluble inorganic materials include silica, aluminosilicates, aluminas, calcium carbonate, barium sulphate, titanium dioxide and pigments.
• Preferred water insoluble materials are silica, materials consisting of at least 70% silica by weight, and, aluminosilicates.
• the aluminosilicate is preferably a crystalline aluminosilicate, usually a zeolite, particularly a zeolite suitable for use in a detergent formulation.
• Useful zeolites include zeolite P, A, X and Y and mixtures thereof, with zeolite P and zeolite A being preferred. Zeolite P is especially preferred.
• a type of Zeolite P known as maximum aluminium zeolite P e.g. DOUCIL A24 ex Ineos Silicas, UK
• M represents a metallic cation having a valency of n
• x indicates the ratio of atoms of silica to atoms of aluminium
• y indicates the ratio of molecules of water to atoms of aluminium.
• M is an alkali metal.
• Zeolites of use in this invention may have the structure of any known zeolites.
• the structure and characteristics of many zeolites are described in the standard work "zeolite Molecular Sieves" by Donald W Brock, published by Robert E Krieger Publishing Company.
• x in the above empirical formula is in the range 1.5 to 10.
• Zeolites useful in this invention may be based on naturally- occurring or synthetic aluminosilicates and the preferred forms of zeolite have the structure known as zeolite P, zeolite X or Zeolite A.
• zeolite particularly preferred forms are those disclosed in EP-A-0 384 070, EP-A-565 364, EP-A-0 697 010, EP- A-0 742 780, WO 96/34828 and WO 97/06102, the entire contents of which are incorporated herein by reference.
• the zeolite P described in EP-A-0 384 070 has the empirical formula given above in which M represents an alkali metal cation and x has a value up to 2.66, preferably in the range 1.8 to 2.66, and has a structure that is particularly useful according to the invention and is known as maximum aluminium zeolite P as described above .
• the granular disintegrants of the invention are more effective when the zeolites used to prepare them contain relatively little water.
• the preferred amount of water in the zeolite depends upon the type of zeolite used. For zeolites A and P, it is preferred that the amount of water is less than 21% by weight of the zeolite, more preferably less than 15% by weight, especially 8 to 13% by weight, such as 9 to 12% by weight.
• a particularly useful form of zeolite P which contains from about 9 to about 12% by weight of water is zeolite MAP. As the water content in zeolite P is increased above this range, the effectiveness as a disintegrant decreases with increasing water content. Fully hydrated zeolite P has been found to be less effective as a disintegrant when compared to zeolite MAP.
• the zeolite used as the inorganic carrier shows a volume increase upon contact with water at 20°C.
• the relative amount of the water-swelling clay and the water- insoluble inorganic material, particularly the crystalline aluminosilicate, in the granular disintegrant is preferably in the weight ratio range of from 9:1 to 1:9, more preferably 6:1 to 1:5, such as 2:1 to 1:4 by weight of the clay: inorganic material. Good results have been obtained with ratios in the range from 1.5:1 to 1:3 by weight water-swelling clay: inorganic material .
• the water-swelling clay is preferably present in the disintegrant granule in an amount of from 10 to 50% by weight, preferably 20 or 25% to 45% by weight, such as 30 to 40% by weight based on the weight of the disintegrant granule.
• the water-insoluble inorganic material is preferably present in an amount of from 35 to 80% by weight preferably 45 to 70% by weight, such as 50 to 60% by weight based on the weight of the disintegrant granule.
• the water-swellable agent is preferably present in an amount of from 1 to 10% by weight, preferably 3 to 9% by weight, such as 5 to 9% by weight based on the weight of the disintegrant granule.
• Alkali metal aluminosilicates are commonly used in detergent compositions as builders as further described hereinbelow.
• a composition according to the invention comprises an alkali metal aluminosilicate as a detergency builder
• the builder e.g. aluminosilicate constituent, typically comprises 10 to 60% by weight of the total composition.
• zeolite when used in the disintegrant granules and as a detergency builder in the composition, then at least 1% by weight of the total weight of the composition comprises a zeolite constituent employed in the form of disintegrant granules.
• the water insoluble inorganic materials have a primary average particle size below 10 ⁇ m and, more preferably, the average particle size is below 5 ⁇ m, as measured using a Malvern Mastersizer (Trade Mark)
• the disintegrant granules comprise a water-swellable agent which in its anhydrous state, comprises no more than 15% by weight, more preferably no more than 10% by weight, most preferably no more than 8%wt, such as 7.5% or less of the combined weight of said swelling clay, said water insoluble inorganic material and said water-swellable agent in the granular disintegrant .
• a water-swellable agent which in its anhydrous state, comprises no more than 15% by weight, more preferably no more than 10% by weight, most preferably no more than 8%wt, such as 7.5% or less of the combined weight of said swelling clay, said water insoluble inorganic material and said water-swellable agent in the granular disintegrant .
• at least 1% of the combined weight of said swelling clay, said inorganic material and said water-swellable agent in the granular disintegrant comprises water-swellable agent.
• the water-swellable agent comprises 1 to 8% by weight of the combined weight of the water-swell
• a relatively small amount of the water-swellable agent may, surprisingly, be used in the tabletted composition of the invention whilst still providing acceptable properties in the tabletted composition.
• the amount of water-swellable agent in the tabletted composition is less than 2% by weight, preferably less than 1% of the composition.
• at least 0.2% by weight of the water-swellable agent, based on the total weight of the tabletted composition is present .
• the water-swellable agent comprises a polymer, often a wholly or partially cross-linked polymer, e.g.
• the water swellable agent in the disintegrant granule is preferably a cross-linked carboxymethyl cellulose, such as AquasorbTM A500 and Ac-Di-SolTM and NilynTM XL 90 as mentioned above.
• Cross-linked sodium carboxymethyl cellulose is especially preferred. It is believed that these cross-linked carboxymethyl celluloses have particularly suitable levels of cross-linking and/or degree of substitution for use in the present invention.
• compositions of the invention will contain from 1 to 20% by weight of the disintegrant granules based on the total weight of the compositions, preferably 1 or 2% to 15%, such as 3 to 10%, e.g. 4 to 8% by weight of the disintegrant granules. If the granules are included to aid dissolution of the tablets rather than disintegration, then the amount of the granules in the tablets could be as low as 1% by weight.
• the water-swellable agent preferably has an average primary particle size up to about 600um, but, conveniently, has an average primary particle size of no more than 200 um, preferably no more than lOOum.
• the water swellable agent preferably has a water-swelling capacity of at least 5 cm 3 /gram, preferably 10 cm 3 /gram and more preferably 20 cm 3 /gram as determined in the test described hereinbelow.
• the disintegrant granules preferably have a mean particle size in the range 250 to 1500 micrometers, more preferably 500 to 1200 microns, most preferably 700 to 1200 microns.
• the granules of swelling clay, water insoluble inorganic material and water-swellable agent are in a preferred embodiment prepared by a dry granulation process.
• a typical known process for producing granules of inorganic material comprises mixing the inorganic material with water or an aqueous liquid, agitating the wet mixture until granules are formed and subsequently removing water from the granules .
• the dry granulation process of the current invention the granules are produced without the use of water or an aqueous liquid.
• the dry granulation process can be any of the processes that will be known to those skilled in the art, e.g.
• roller compactors include the Alexanderwerk WP50 manufactured by Alexanderwerk AG, Remscheid, Germany, the IR520 Chilsonator available from Fitzpatrick Company, Illinois, USA and a roller compactor from Hosokawa Bepex of Minneapolis, USA.
• a typical small-scale preparative method is now described in detail. Swelling clay, inorganic material, and particles of the water-swellable agent are blended together in appropriate portions in a Pek mixer for 30 minutes.
• a minimum of 2 kg of blended material so prepared is compacted by feeding into an Alexanderwerk roller compactor, fitted with a sintered block vacuum de-aeration system.
• the roller pressure is selected according to the strength of granule desired, higher pressures leading to stronger granules. Generally, roller pressure is between 8 and 25 Mpa and a typical roller pressure is 10 Mpa.
• the compacted material from the compactor is fed into a granulator, which forms part of the machine, and forced through a mesh and the resulting granules are then screened to the desired particle size range, e.g. a mean average particle size of 250 to 3000 um, using standard laboratory sieves. Preferably the particles have a particle size of 700 to 1500 um.
• the granules, however produced, comprise an intimate mixture of particles of swelling clay, inorganic material and water- swellable agent.
• An especially effective disintegrant granule has been found to be one comprising a mixture, preferably co-granulated, of a bentonite clay produced by treating calcium-form bentonite with a compound of sodium, zeolite MAP and a cross-linked sodium carboxy methyl cellulose.
• compositions of this invention contain one or more non-soap surfactants.
• these preferably provide from 5 to 50% by weight of the composition of the tablet or region thereof, more preferably from 8 or 9% by weight of the composition up to 35% or 40% by weight. If the tablet is composed of more than one discrete region, then these preferred amounts of surfactant may apply to the tablet as a whole.
• the organic surfactant may be present as a component in granulated particles in an amount between 10 and 70% by weight of the particles, more preferably 15 to 50% by weight based on the total weight of the granulated particles. All the surfactant in the composition may be contained within these particles.
• Surfactant may be anionic (soap or non-soap) , cationic, zwitterionic, amphoteric, nonionic or a combination of these.
• anionic surfactant may be present in an amount from 0.5 to 50% by weight, preferably from 2% or 4% up to 30% or 35% or 40% by weight of the tablet or region thereof .
• organic surfactant is likely to constitute from 0.5 to 8%, more likely from 0.5 to 5% of the composition of the tablet or region thereof and is likely to consist of nonionic surfactant, either alone or in a mixture with anionic surfactant .
• Synthetic (i.e. non-soap) anionic surfactants are well known to those skilled in the art .
• alkyl benzene sulphonates particularly sodium linear alkyl benzene sulphonates having an alkyl chain length of C 8 -C ⁇ 5 ; olefin sulphonates; alkane sulphonates; dialkyl sulphosuccinates; and fatty acid ester sulphonates.
• Primary alkyl sulphate having the formula:
• R is an alkyl or alkenyl chain of 8 to 18 carbon atoms especially 10 to 14 carbon atoms and M + is a solubilising cation, is commercially significant as an anionic surfactant.
• R is linear alkyl of 8 to 15 carbon atoms and M + is a solubilising cation, especially sodium, is also a commercially significant anionic surfactant.
• such linear alkyl benzene sulphonate or primary alkyl sulphate of the formula above, or a mixture thereof will be the desired anionic surfactant and may provide 75 to 100 wt% of any anionic non-soap surfactant in the composition.
• the amount of non-soap anionic surfactant lies in a range from 5 to 20 or 25 wt% of the tablet or region thereof .
• soaps of fatty acids are preferably sodium soaps derived from naturally occurring fatty acids, for example, the fatty acids from coconut oil, beef tallow, sunflower or hardened rape seed oil.
• Suitable nonionic surfactant compounds which may be used include in particular the reaction products of compounds having a hydrophobic group and a reactive hydrogen atom, for example, aliphatic alcohols, acids, amides or alkyl phenols with alkylene oxides, especially ethylene oxide.
• Nonionic surfactant compounds are alkyl (C 8 _ 2 2) phenol- ethylene oxide condensates, the condensation products of linear or branched aliphatic C 8 -2o primary or secondary alcohols with ethylene oxide, and products made by condensation of ethylene oxide with the reaction products of propylene oxide and ethylene-diamine .
• the primary and secondary alcohol ethoxylates especially the C 9 -.n and C 1 2-1 5 primary and secondary alcohols ethoxylated with an average of from 5 to 20 moles of ethylene oxide per mole of alcohol.
• the amount of nonionic surfactant lies in a range from 4 to 40% by weight, better 4 or 5 to 30% by weight of the composition of the tablet or region thereof.
• Many nonionic surfactants are liquids. These may be absorbed onto particles of the composition prior to compaction into tablets .
• Amphoteric surfactants which may be used jointly with anionic or nonionic surfactants, or both, include amphopropionates of the formula
• RCO is an acyl group of 8 to 18 carbon atoms, especially coconut acyl .
• amphoteric surfactants also includes amine oxides and also zwitterionic surfactants, notably betaines of the general formula;
• R is an aliphatic hydrocarbon chain which contains 7 to 17 carbon atoms
• R 2 and R 3 are independently hydrogen, alkyl of 1 to 4 carbon atoms or hydroxyalkyl of 1 to 4 carbon atoms such as CH 2 OH
• Y is CH 2 or of the form CONHCH 2 CH 2 CH 2 (amidopropyl betaine)
• Z is either a COO " (carboxybetaine) , or of the form CHOHCH 2 S0 3 - (sulfobetaine or hydroxy sultaine) .
• amphoteric surfactant is amine oxide of the formula
• R x is C ⁇ 0 to C 20 alkyl or alkenyl
• R 2 , R 3 and R 4 are each hydrogen or C x to C 4 alkyl, while n is from 1 to 5.
• Cationic surfactants may possibly be used. These frequently have a quaternised nitrogen atom in a polar head group and an attached hydrocarbon group of sufficient length to be hydrophobic .
• a general formula for one category of cationic surfactants is ;
• each R independently denotes an alkyl group or hydroxyalkyl group of 1 to 3 carbon atoms and R h denotes an aromatic, aliphatic or mixed aromatic and aliphatic group of 6 to 24 carbon atoms, preferably an alkyl or alkenyl group of 8 to 22 carbon atoms and X " is a counterion.
• the amount of amphoteric surfactant, if any, may be from 3% to 20 or 30% by weight of the tablet or region of a tablet; the amount of cationic surfactant, if any, may be from 1% to 10 or 20% by weight of the tablet or region of a tablet.
• a composition which is compacted to form tablets or tablet regions typically contains a detergency builder which serves to remove or sequester calcium and/or magnesium ions in the water.
• the builder acts as a water softener.
• the amount of builder is likely to be from 5% to 80%, more usually 10% or 15% to 40%, 55% or 60% by weight of the tablet.
• the detergency builder may be present in granulated particles in an amount of from 20 to 80% by weight, more preferably 20%, 25% or 30 to 60% by weight.
• Detergency builders may be provided wholly by water soluble materials, or may be provided in large part or even entirely by water-insoluble material with water-softening properties.
• Alkali metal aluminosilicates are strongly favoured as environmentally acceptable detergency builders for fabric washing, and are preferred in this invention.
• Alkali metal (preferably sodium) aluminosilicates may be either crystalline or amorphous or mixtures thereof, having the general formula:
• xH 2 0 Some bound water (indicated as xH 2 0) and are required to have a calcium ion exchange capacity of at least 50 mg CaO/g.
• the preferred sodium aluminosilicates contain 1.5-3.5 Si0 2 units (in the formula above). Both the amorphous and the crystalline materials can be prepared readily by reaction between sodium silicate and sodium aluminate, as amply described in the literature.
• Suitable crystalline sodium aluminosilicate ion-exchange materials are described, for example, in GB 1 429 143 (Procter & Gamble) .
• the preferred sodium aluminosilicates of this type are the well known commercially available zeolites A and X, the newer zeolite P described and claimed in EP 384 070 (Unilever) and mixtures thereof.
• This form of zeolite P is also referred to as "zeolite MAP" as referred to hereinabove.
• a detergency builder could be a layered sodium silicate as described in US 4 664 839.
• NaSKS-6 is the trademark for a crystalline layered silicate marketed by Hoechst (commonly abbreviated as "SKS-6") .
• KS-6 has the delta-Na 2 Si0 5 morphology form of layered silicate. It can be prepared by methods such as described in DE-A-3 , 17, 649 and DE-A-3 , 742 , 043.
• layered silicates such as those having the general formula NaMSi x 0 2x+ ⁇ .yH 2 0 wherein M is sodium or hydrogen, x is a number from 1.9 to 4, preferably 2, and y is a number from 0 to 20, preferably 0 can be used.
• the less preferred category of water-soluble phosphorus- containing inorganic softeners includes the alkali-metal orthophosphates, metaphosphates, pyrophosphates and polyphosphates .
• Specific examples of inorganic phosphate detergency builders include sodium and potassium tripolyphosphates, orthophosphates and hexametaphosphates .
• Non-phosphorus water-soluble detergency builders may be organic or inorganic.
• Inorganics that may be present include alkali metal (generally sodium) carbonate; while organics include polycarboxylate polymers, such as polyacrylates, acrylic/maleic copolymers, and acrylic phosphonates, monomeric polycarboxylates such as citrates, gluconates, oxydisuccinates, glycerol mono- di- and trisuccinates, carboxymethyloxysuccinates , carboxymethyloxymalonates, dipicolinates and hydroxyethyliminodiacetates .
• alkali metal generally sodium
• organics include polycarboxylate polymers, such as polyacrylates, acrylic/maleic copolymers, and acrylic phosphonates, monomeric polycarboxylates such as citrates, gluconates, oxydisuccinates, glycerol mono- di- and trisuccinates, carboxymethyloxysuccinates , carboxy
• Tablet compositions preferably include polycarboxylate polymers, more especially polyacrylates and acrylic/maleic copolymers which have some function as water-softening agents and also inhibit unwanted deposition onto fabric from the wash liquor.
• the tablet contains water soluble builder it is preferably present in an amount of from 10 to 80% by weight based on the total weight of the tablet or region thereof. Where the tablet contains water in-soluble builder it is preferably present in an amount of from 5 to 80% by weight based on the total weight of the tablet or region thereof.
• Tablets comprising from 4 to 50% by weight of surfactant and from 5 to 80% by weight of builder are especially preferred for fabric washing tablets. Tablets comprising from 1 to 5% by weight of surfactant and from 50 to 98% of detergency builder are especially preferred for machine dishwashing tablets.
• the percentage ranges for the components referred to herein may apply to the overall composition of the tablet, as well as to at least one region of the tablet .
• compositions of the invention in either the whole tablet or in a region thereof, may contain water-soluble disintegration promoting particles in addition to the disintegrant granules. It is preferred that such disintegration-promoting particles make up from 2%, 3%, 5%, 8% or 10% up to 15%, 20%, 25% or 30% by weight of the composition of the tablet or region thereof. It is especially preferred that such disintegration-promoting particles make up from 5% to 25% by weight of the composition, based on the total weight of the composition.
• Such soluble particles typically contain at least 40% (of their own weight) of one or more materials which is other than soap or organic surfactant and which has a solubility in deionised water of at least 30g/l00g at 20°C.
• at least a part of the water-soluble disintegration-promoting particles is added to a pre-granulated portion of the composition used to produce the tablet.
• a small proportion of such soluble material may also be included in granulated particles which may contain organic surfactant and/or detergency builder, in an amount of preferably 1 to 25% by weight, more preferably 3 or 5% to 10% or 15% by weight of these granulated particles.
• this water-soluble material is selected from compounds containing at least 40% (by weight of the particles) of one or more materials selected from the group consisting of; compounds with a water-solubility exceeding 50 grams/100 grams in water at 20°C; or sodium tripolyphosphate containing at least 50% of its own weight of the phase I anhydrous form; or sodium tripolyphosphate which is partially hydrated so as to contain water of hydration in an amount which is at least 0.5% by weight of the sodium tripolyphosphate in the particles .
• these disintegration- promoting particles can also contain other forms of tripolyphosphate or other salts within the balance of their composition.
• the material in such water-soluble disintegration-promoting particles can function as a detergency builder, (as is the case with sodium tripolyphosphate) then of course it contributes to the total quantity of detergency builder in the tablet composition.
• a solubility of at least 50 g/lOOg of deionised water at 20°C is an exceptionally high solubility: many materials which are classified as water soluble are less soluble than this.
• this highly water soluble material is incorporated as particles of the material in a substantially pure form (i.e. each such particle contains over 95% by weight of the material) .
• the said particles may contain material of such solubility in a mixture with other material, provided that material of the specified solubility provides at least 50% by weight of these particles .
• Preferred water-soluble materials having a solubility exceeding 50 grams/100 grams of deionised water at 20°C are sodium citrate dihydrate, urea, and sodium acetate which may be in a partially or fully hydrated form (trihydrate) .
• sodium acetate trihydrate is especially preferred.
• the highly water-soluble material is a salt which dissolves in water in an ionised form. As such a salt dissolves it leads to a transient local increase in ionic strength which can assist disintegration of the tablet by preventing nonionic surfactant from swelling and inhibiting dissolution of other materials.
• tablets of this invention may contain water- soluble salt, with a solubility exceeding 50g/l00g of deionised water at 20°C, both as a small percentage within the said granulated particles and as separate particles which are mixed with them.
• such highly water soluble salt may be present in an amount from 0 to 30% by weight of those particles, preferably from 3 to 10% or 15% thereof, while the materials added to those particles before tabletting may be such highly soluble salts in an amount from 2 or 5% up to 15% of the whole tablet formulation.
• the said particles which promote disintegration are particles which contain sodium tripolyphosphate with more than 50% (by weight of the particles) of the anhydrous phase I form, and, which is partially hydrated so as to contain water of hydration in an amount which is at least 1% by weight of the sodium tripolyphosphate .
• phase II which is the low temperature form
• phase I which is stable at high temperature.
• the conversion of phase II to phase I proceeds fairly rapidly on heating above the transition temperature, which is about 420°C, but the reverse reaction is slow. Consequently phase I sodium tripolyphosphate is metastable at ambient temperature .
• a process for the manufacture of particles containing a high proportion of the phase I form of sodium tripolyphosphate by spray drying below 420°C is given in US-A-4 536 377.
• These particles should also contain sodium tripolyphosphate which is partially hydrated.
• the extent of hydration should be at least 1% by weight of the sodium tripolyphosphate in the particles. It may lie in a range from 1 to 4%, or it may be higher. Indeed fully hydrated sodium tripolyphosphate may be used to provide these particles.
• the remainder of the tablet composition used to form the tablet or region thereof may include additional sodium tripolyphosphate.
• This may be in any form, including sodium tripolyphosphate with a high content of the anhydrous phase II form. Suitable material is commercially available. Suppliers include Rhone-Poulenc, France and Rhodia, UK.
• a zero-phosphate tablet in accordance with this invention may utilise a suitable amount, e.g. 15% by weight or more of disintegration-promoting material with solubility of at least 50gm/100gm at 20°C.
• suitable amount e.g. 15% by weight or more of disintegration-promoting material with solubility of at least 50gm/100gm at 20°C.
• Other countries permit the use, or at least some limited use, of phosphates, making it possible to use some sodium tripolyphosphate.
• Tablets of the present invention may include a water-soluble organic polymer which is solid at 25 °C to act as a binder for the particulate composition when compacted. This may be included in granulated particles containing organic surfactant and/or detergency builder.
• solid is used here to denote materials which have the appearance of an immobile solid at 25 °C and can be handled as solids. They contrast with liquids which, even if viscous, can be seen to be capable of fluid flow.
• Organic polymers are general amorphous materials which are strictly classified as supercooled liquids - but of such high viscosity that for practical purposes they are solid.
• water-soluble is used here in relation to this organic polymer to indicate that when the polymer is placed in water it appears, on visual inspection, to dissolve. Whether the solution is a true isotropic solution or has some colloidal character is not important to this invention. It is preferred that the polymer material should melt at a temperature of at least 35°C, better 40°C or above, which is above ambient temperatures in many temperate countries . For use in hotter countries it will be preferable that the melting temperature is somewhat above 40°C, so as to be above the ambient temperature.
• Some polymers which may be used are solids at temperatures up to 100°C, that is to say they retain a solid appearance even though they are in an amorphous state. They may soften and melt to a mobile liquid on heating further, or may decompose without melting on heating sufficiently in excess of 100°C. Such polymers will generally be added as a powder during the course of granulation. Another possibility would be addition as a solution in a volatile organic solvent, but that is not preferred.
• polymers which may be used melt to liquid form at temperatures not exceeding 80°C and may be sprayed as molten liquid onto the surfactant and builder mixture during the course of granulation.
• Organic polymers are in general amorphous solids.
• a significant parameter characterising amorphous solids is their glass transition temperature.
• an amorphous hydrophilic polymer absorbs moisture, the moisture acts as a plasticiser and lowers the glass transition temperature of the polymer.
• Suitable polymers may have a glass transition temperature, when anhydrous, which is from 300 to 500K (i.e. approximately 25°C to 225 °C) but may be incorporated in a moisture-containing state so that their glass transition temperature is lower.
• a preferred polymer is polyethylene glycol .
• Preferred polymer materials are synthetic organic polymers especially polyethylene glycol. Polyethylene glycol of average molecular weight 1500 (PEG 1500) melts at 45°C and has proved suitable.
• Polyethylene glycol of higher molecular weight can also be used (PEG 4000 melts at 56°C and PEG 6000 at 58°C).
• Other possibilities are polyvinylpyrrolidone, and polyacrylate and water-soluble acrylate copolymers.
• the amount of water-soluble polymer included in particles which may also contain organic surfactant and detergency builder is preferably between 0.2% or 0.5% or 1% and 15% by weight of the particles, possibly at least 1.5 or 3%. Further preferred is that the amount is not over 7 or 10% by weight.
• the amount of water-soluble polymer present may be defined in terms of the whole composition of the tablet or region thereof, in which case, it is desirably present in an amount of between 0.5% and 5% by weight, more preferably 0.5 to 4% by weight. In some cases the addition of the polymer has been found to hinder slightly, the disintegration of the tablet.
• the level of the water-soluble polymer is preferably in the range 0.5 to 2% by weight.
• compositions according to the invention may contain a bleach system.
• a bleach system preferably comprises one or more peroxy bleach compounds, for example, inorganic persalts or organic peroxyacids, which may be employed in conjunction with activators to improve bleaching action at low wash temperatures. If any peroxygen compound is present, the amount is likely to lie in a range from 10 to 25% by weight of the composition of the tablet or region thereof.
• Preferred inorganic persalts are sodium perborate monohydrate and tetrahydrate, and sodium percarbonate, advantageously employed together with an activator.
• Bleach activators also referred to as bleach precursors, have been widely disclosed in the art.
• Preferred examples include peracetic acid precursors, for example, tetraacetylethylene diamine (TAED) , now in widespread commercial use in conjunction with sodium perborate and percarbonate; and perbenzoic acid precursors.
• TAED tetraacetylethylene diamine
• the quaternary ammonium and phosphonium bleach activators disclosed in US 4 751 015 and US 4 818 426 (Lever Brothers Company) are also of interest.
• Another type of bleach activator which may be used, but which is not a bleach precursor is a transition metal catalyst as disclosed in EP-A-458 397, EP-A-458 398 and EP-A-549 272.
• a bleach system may also include a bleach stabiliser (heavy metal sequestrant) such as ethylenediamine tetramethylene phosphonate and diethylenetriamine pentamethylene phosphonate .
• Tablets according to the invention may comprise one or more detergency enzymes.
• the enzyme is selected from amylase, protease, cellulase, lipase and mixtures thereof.
• the aforementioned enzymes are designed to remove a variety of soils and stains from fabrics.
• Detergency enzymes well known in the art for their ability to degrade and aid in the removal of various soils and stains.
• suitable proteases are Maxatase (Trade Mark) , as supplied by Gist-Brocades N.V. , Delft, Holland, and Alcalase (Trade Mark) , and Savinase (Trade Mark) , as supplied by Novo Industri A/S, Copenhagen, Denmark.
• Detergency enzymes are commonly employed in the form of granules or marumes, optionally with a protective coating, in amount of from about 0.1% to about 3.0% by weight of the composition of the tablet or region thereof; and these granules or marumes present no problems with respect to compaction to form a tablet.
• the tablets of the invention may also contain a fluorescer (optical brightener) , for example, Tinopal (Trade Mark) DMS or Tinopal CBS available from Ciba-Geigy AG, Basel, Switzerland.
• Tinopal DMS is disodium 4 , 4 'bis- (2-morpholino-4-anilino-s- triazin-6-ylamino) stilbene disulphonate
• Tinopal CBS is disodium 2, 2 ' -bis- (phenyl-styryl) disulphonate.
• An antifoam material is advantageously included if organic surfactant is present, especially if a detergent tablet is primarily intended for use in front-loading drum-type automatic washing machines.
• Suitable antifoam materials are usually in granular form, such as those described in EP 266 863A (Unilever) .
• Such antifoam granules typically comprise a mixture of silicone oil, petroleum jelly, hydrophobic silica and alkyl phosphate as antifoam active material, sorbed onto a porous absorbed water-soluble carbonate-based inorganic carrier material .
• Antifoam granules may be present in an amount up to 5% by weight of the composition of the tablet or region thereof.
• a tablet of the invention includes an amount of an alkali metal silicate, particularly sodium ortho-, meta- or disilicate.
• an alkali metal silicate particularly sodium ortho-, meta- or disilicate.
• a composition for fabric washing will generally not contain more than 15wt% silicate.
• a tablet for machine dishwashing will frequently contain at least 20wt% silicate.
• the starting particulate composition from which the tablets are produced may in principle have any bulk density
• the present invention may be especially relevant to tablets of detergent composition made by compacting powders of relatively high bulk density, because of their greater tendency to exhibit disintegration and dispersion problems.
• Such tablets have the advantage that, as compared with a tablet derived from a low bulk density powder, a given dose of composition can be presented as a smaller tablet .
• the starting particulate composition may suitably have a bulk density of at least 400 g/litre, preferably at least 500 g/litre, and possibly at least 600 g/litre.
• Granular detergent compositions of high bulk density prepared by granulation and densification in a high-speed mixer/granulator, as described and claimed in EP-A-340 013 (Unilever) , EP-A-352 135 (Unilever) , and EP-A-425 277
• WO-A- 98/11193 Another particularly suitable process for the preparation of a high-bulk density detergent powder is described in WO-A- 98/11193 (Unilever) .
• a feedstock of the starting acid for production of the anionic surfactant is partially neutralised, for example by sodium hydroxide, before being fed into a high-speed mixer densifier (e.g. Lodige CB 30 Recycler) where the partially neutralised acid feedstock is completely neutralised, whilst being mixed with the majority of other components of the detergent base powder granule.
• This powder can be further densified by treating in a moderate speed mixer (e.g. Lodige KM 300 mixer), before which stage further detergency builder may be added.
• a moderate speed mixer e.g. Lodige KM 300 mixer
• the water-soluble polymer material is preferably added before the further densification step, although it may be added in the first mixer.
• the water- soluble polymer material may be heated to a temperature considerably above its melting point to obtain a free-flowing liquid.
• the resulting powder can be cooled and dried using a fluid bed, after which any desired particle size control can be exercised.
• any separate particles containing further components of the finished formulation can be mixed with the base powder prior to compaction.
• Particle sizes can be controlled in the manufacturing process of any particles included in the composition. Oversize particles are usually removed by sieving (for example by a
• Mogensen screen at the end of the production process, followed by milling and recycling of the removed oversize fraction.
• Undersize particles can also be removed by sieving, or if the manufacturing process employs a fluidised bed undersized particles may be entrained in the air stream and subsequently recovered from it for recycling to the granulation stage .
• the average particle size of granulated particles forming the particulate composition from which the tablet is formed is between 400 and 1100 micrometers, preferably between 500 and 1000 micrometers. Preferably no more than 5% of these particles is smaller than 200 micrometers while no more than 5% is larger than 1400 micrometers.
• Materials which are mixed with the granulated particles may also comply with these requirements concerning particle size. These materials (post-added) typically comprise from 5% - 60% by weight of the total weight of the final composition, more usually 35 to 55% by weight.
• Tabletting Tabletting entails compaction of a particulate composition.
• tabletting machinery is known, and can be used. Generally it will function by stamping a quantity of the particulate composition which is confined in a die. Tabletting may be carried out at ambient temperature or at a temperature above ambient which may allow adequate strength to be achieved with less applied pressure during compaction.
• the particulate composition is preferably supplied to the tabletting machinery at an elevated temperature. This will of course supply heat to the tabletting machinery, but the machinery may be heated in some other way also. If any heat is supplied, it is envisaged that this will be supplied conventionally, such as by passing the particulate composition through an oven, rather than by any application of microwave energy.
• the size of a tablet will suitably range from 10 to 160 grams, preferably from 15 to 60 g, depending on the conditions of intended use, and whether it represents a dose for an average load in a fabric washing or dishwashing machine or a fractional part of such a dose.
• the tablets may be of any shape.
• blocks of substantially uniform cross-section such as cylinders or cuboids .
• the overall density of a tablet for fabric washing preferably lies in a range from 1040 or 1050g/litre preferably at least HOOg/litre up to 1400g/litre.
• the tablet density may well lie in a range up to no more than 1350 or even 1250g/litre.
• the overall density of a tablet of some other cleaning composition such as a tablet for machine dishwashing or as a bleaching additive, may range up to 1700g/litre and will often lie in a range from 1300 to 1550g/litre.
• the detergent tablet may be made by a process which comprises mixing said disintegrant granules with the other constituents of the composition, placing a quantity of the resultant particulate composition within a mould, and, compacting the composition within the mould to produce the tablet .
• the speed of disintegration of the tablets in the examples was measured by means of a test procedure under static conditions in which a pre-weighed tablet was placed on a metal grid with 1 X 1 cm mazes and the tablet and grid was then immersed in a suitable amount of 15° FH (French Hardness) tap water at 10°C or 20°C so that the tablet when immersed is covered by 2cm of water. After 60 seconds the metal grid is carefully taken out of the water and the wet tablet residue is weighed. If the tablet had fully disintegrated in this time then the time taken for 100% disintegration is recorded.
• FH Frnch Hardness
• the tablets exhibit 70% or more disintegration in the above test, more preferably 75% or more, most preferably 80% or more.
• DFS diametrical fracture stress in Pascals
• F max is the applied load in Newtons to cause fracture
• D is the tablet diameter in metres
• t is the tablet thickness in metres.
• the test is carried out using an Instron type universal testing instrument to apply compressive force on a tablet diameter (i.e. perpendicular to the axis of a cylindrical tablet). It is preferred that tablets have a DFS of at least 20kPa more preferably at least 25kPa, such as 30kPa or above.
• the tablets when used as fabric washing tablets in an automatic washing machine, may be added either to the powder dispensing draw, or, directly in to the washing drum. This may occur either manually or automatically.
• the detergent/cleaning tablets of the invention are suitable for use in what is known in the art as ⁇ homecare' applications. That is, detergent tablets which are suitable for use in cleaning and maintenance operations typically carried out around the home. It does not include operations carried out directly on a human or animal body which are known as ⁇ personal care' applications.
• ⁇ homecare' detergent tablets include; laundry tablets, (machine) dishwashing tablets, hard- surface cleaning tablets, toilet-cleaning tablets, bleaching tablets, water-softening tablets etc.
• a stock granular detergent powder was made by granulating the ingredients above the entry "post-dosed ingredients” under high shear followed by densification under reduced shear to produce a granulated component. The post-dosed ingredients were then added as described above under the heading "Granulation Process” to produce a detergent powder of the overall composition in table 1.
• DOUCIL iP1 A24' is a maximum aluminium zeolite P (MAP) ex
• NDOM is non detergent organic matter
• SOKALANTM HP23 is a grafted co-polymer of polyethylene oxide and polyvinylacetate ex BASF, Germany.
• DEQUESTTM 2047 is ethylene diamine tetra methylene phosphonate ex Monsanto
• DEQUEST 1 2016 is ethylene hydroxy diphosphonate ex Monsanto .
• Disintegrant Granules A to F Six disintegrant granules were prepared by the typical preparative method described above under the heading
• Disintegrant granules The granules had the compositions given in table 2 and were sieved to collect the fraction having a particle size of 500 to 1200 um unless otherwise stated.
• the amounts given in Table 2 are the percentages of each ingredient by weight in the disintegrant granule and add up to 100% by weight based on the total weight of the granule.
• Ac-Di-SolTM is the water-swellable agent.
• Brebent clay a water-swelling calcium-form bentonite clay which has been treated with sodium carbonate and which is sold under the name BREBENTTM ex Laporte PLC. Cross-linked carboxymethyl cellulose ex FMC Corporation, USA.
• Comparative examples Cl to C5 were produced having the composition as shown in table 3.
• each comparative composition 40g portions of each comparative composition were made into cylindrical tablets of 44.5 mm diameter and height 18-22 mm using a Graseby Specac laboratory tabletting machine.
• the compaction pressure used for each tablet was adjusted so that the tablets were all compacted to the same diametrical fracture stress of 30 kPa .
• the strength of the tablets, in their dry state as made on the press, was determined as their diametrical fracture stress DFS by the method detailed in the description of the invention above.
• compositions were compacted as detailed above for comparative examples Cl etc above.
• the speed of disintegration of the tablets was measured under static conditions as described above under the heading "Tablet testing - disintegration” .
• the disintegration results are given in table 5.
• the “initial” result is the disintegration result obtained for tablets made and tested on the same day.
• the “storage” result is the disintegration result obtained for tablets made and stored at 20°C in a closed container for 14 days before being tested for disintegration.
• Comparative example C6 was prepared as shown in table 6.
• the disintegrant granule components are expressed as parts by weight .
• C6 shows excellent disintegration but requires 21% by weight of a disintegration promoting particle material plus 5% by weight of a disintegrant granule.
• the tablets according to the invention also show acceptable disintegration but at much lower total levels of disintegration promoting particle material and disintegrant granule. This allows greater amounts of the stock' composition to be used in the tablets.
• the additional improvement in disintegration obtained by including a disintegration promoting particle material in the composition in addition to the disintegrant granule can be seen by comparing the results obtained for examples 3, 5, 4 and 8. Comparative example C7.
• Comparative example C7 was produced as shown in table 9. The granule components are expressed as parts by weight.
• compositions were compacted as detailed above for comparative examples Cl etc.
• the tablets according to the invention show good disintegration compared to a tablet comprising a disintegrant granule which comprised zeolite but no clay.
• the stock detergent powder of table 1 was mixed with disintegrant granule b and additional sodium acetate/zeolite blend to produce examples 15 to 17 which are examples according to the invention as detailed in table 12.
• compositions were compacted as detailed above for comparative examples Cl etc above.
• the stock detergent powder of table 1 was mixed with disintegrant granule A and additional sodium acetate/zeolite blend, and the additional minor ingredients to produce examples 18 and 19 which are examples according to the invention as detailed in table 14.
• compositions were compacted as detailed above for comparative examples Cl etc.

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