CA2315298A1 - Washing and cleaning agent shaped body with bleaching agent - Google Patents

Abstract

This invention relates generally to cleaning tablets containing bleaching agents. More particularly, the invention relates to such tablets as laundry detergent tablets, dishwasher tablets, bleach tablets and water softener tablets containing bleaching agents. Cleaning tablets of compacted particulate detergent/cleaner comprising bleaching agent, builder(s) and optionally other ingredients of washing/cleaning compositions, wherein the bleaching agent has a mean particle size above 0.4 mm.

Description

' CA 02315298 2000-08-17 WASHING AND CLEANING AGENT SHAPED BODY
WITH BLEACHING AGENT
Field of the Invention This invention relates generally to cleaning tablets containing bleaching agents. More particularly, the invention relates to such tablets as laundry detergent tablets, dishwasher tablets, bleach tablets and water softener tablets containing bleaching agents.
Background of the Invention Washing/cleaning compositions in the form of tablets have long been known and are widely described in the prior art although, hitherto, tablets have not been especially prominent on the market. The reason for this is that tablets, despite a number of advantages, also have disadvantages which have an adverse effect both on their production and use and on their acceptance by consumers. The main advantages of tablets, such as elimination of the need to measure out the quantity of product required by the consumer, the higher density and hence the reduced packaging and storage costs and an aesthetic aspect which should not be underestimated, are offset by such disadvantages as the dichotomy between acceptable hardness and sufficiently rapid disintegration and dissolution of the tablets and numerous technological difficulties in production and packaging.
In particular, the dichotomy between a sufficiently hard tablet and a :?0 sufficiently fast disintegration time is a central problem. Since sufficiently stable, i.e. dimensionally stable and fracture-resistant, tablets can only be produced by applying relatively high tabletting pressures, the tablet ingredients are heavily compacted which delays disintegration of the tablet in the aqueous wash liquor and hence leads to excessively slow release of the active substances in the :?5 washing process. The delayed disintegration of the tablets has the further ' CA 02315298 2000-08-17 disadvantage that conventional detergent tablets cannot be flushed into the washing process from the dispensing compartment of domestic washing machines because the tablets do not disintegrate sufficiently quickly into secondary particles which are small enough to be flushed into the drum of the washing machine from the dispensing compartment.
Many proposals have been put forward in the prior art with a view to overcoming the dichotomy between hardness, i.e. transportation and handling stability, and easy disintegration of the tablets. One proposed solution which is known in particular from the pharmaceutical field and which has been extended '10 to detergent tablets is to incorporate certain disintegration aids which facilitate the access of water or which have a swelling or effervescing or other disintegrating effect on contact with water. Other proposed solutions from the patent literature include the tabletting of premixes with certain particle sizes, the separation of individual ingredients from certain other ingredients and the coating of individual '15 ingredients or the tablet as a whole with binders.
Thus, EP-A-0 522 766 (Unilever) describes tablets of a compacted particulate detergent composition containing surfactants, builders and disintegration aids (for example based on cellulose), the particles being at least partly coated with the disintegration aid which shows both a binder effect and a :?0 disintegrating effect during dissolution of the tablets in water. This document also refers to the general difficulty of producing tablets combining adequate stability with good solubility. The particle size of the mixture to be tabletted is said to be above 200 Nm, the upper and lower limits to the individual particle sizes differing by no more than 700 pm from one another.
25 Other documents concerned with the production of detergent tablets are EP-A-0 716 144 (Unilever), which describes tablets with an outer coating of water-soluble material, and EP-A-0 711 827 (Unilever) which mentions a citrate of defined solubility as an ingredient.
The use of birders which optionally develop a disintegrating effect (more ' CA 02315298 2000-08-17 particularly polyethylene glycol) is disclosed in EP-A-0 711 828 (Unilever) which describes detergent tablets obtained by tabletting a particulate detergent composition at temperatures of 28°C to the melting point of the binder, the tabletting process always being carried out below the melting temperature. It is clear from the Examples of this document that the tablets produced in accordance with its teaching have higher fracture resistances when tabletting is carried out at elevated temperature.
Detergent tablets in which individual ingredients are separated from others are described, for example, in EP-A-0 481 793 (Unilever). The detergent tablets '10 disclosed in this document contain sodium percarbonate which is separated from all other components that could affect its stability.
In none of the cited prior art documents concerned with detergent tablets is any particular significance attributed to the physical characteristics of individual ingredients, especially bleaching agents. None of the documents cited above is '15 concerned with improving the solubility of cleaning tablets by the selective use of bleaching agents in certain particle size ranges.
Accordingly, the problem addressed by the present invention was to provide detergent tablets which would contain bleaching agents and would combine high hardness with excellent disintegration properties. The cleaning :?0 tablets provided by the invention would also be able to be dosed from the dispensing compartment without the consumer experiencing any disadvantages through residues in the dispensing compartment and too little detergent in the wash liquor. Besides these tablet-specific properties, the cleaning performance of the tablets according to the invention would also be exemplary.
:?5 Summary of the Invention The present invention relates to cleaning tablets of compacted particulate detergentlcleaner comprising bleaching agent, builders) and optionally other ingredients of washing/cleaning compositions, characterized in that the bleaching ' CA 02315298 2000-08-17 agent has a mean particle size above 0.4 mm.
In the context of the present invention, the mean particle size is a calculated quantity which is obtained by multiplying the percentage content of a sieve fraction by the mesh width of the sieve. The individual values of such mean values can be scattered over a wide range if, for example, extremely small and extremely large particles are present alongside one another. According to the invention, however, the bleaching agent does not have a broad particle size distribution, but a relatively narrow particle size distribution around the mean value. In particular, so-called fines should be ruled out as far as possible so that preferred detergent tablets according to the invention are characterized in that the bleaching agent i:; substantially free from particles below 0.2 mm in size.
"Substantially free" in the context of the present invention means contents below 2% by weight, preferably below 1 % by weight and more preferably below 0.5% by weight.
According to the invention, not only are dust and fines of the bleaching agent absent as far as possible, the content of particles below 0.4 mm in size should also be kept as small as possible. Thus, preferred cleaning tablets are characterized in that the bleaching agent contains less than 30% by weight, preferably less than 20% by weight and more preferably less than 10% by weight :?0 of particles below 0.4 mm in size.
Accordingly, the percentage of relatively large bleaching agent particles should be as high as possible. In another preferred embodiment, the particles of bleaching agent are not only larger than 0.4 mm in size, but are distinctly larger, for example larger than 0.8 mm. Preferred cleaning tablets are characterized in :?5 that the bleaching agent contains more than 10% by weight, preferably more than 20% by weight and more preferably more than 30% by weight of particles larger than 0.8 mm in size.
Nevertheless, the bleaching agent should not of course be incorporated in the form of large lumps in the cleaning tablets according to the invention.
From the practical point of view, particle sizes of the bleaching agent below 2.0 mm have proved effective, the bleaching agent present in the detergent tablets preferably being substantially free from particles larger than 1.6 mm in size.

5 To develop the required bleaching performance, the cleaning tablets according to the invention contain one or more bleaching agents. Among the compounds yielding H202 in water which serve as bleaching agents, sodium perborate tetrahydrate and sodium perborate monohydrate are particularly important. Other useful bleaching agents are, for example, sodium percarbonate, peroxypyrophosphates, citrate perhydrates and H202-yielding peracidic salts or peracids, such as perbenzoates, peroxophthalates, diperazelaic acid, phthaloiminoperacid or diperdodecane dioic acid. The bleaching agents are also used in varying quantities in the cleaning tables according to the invention, depending on the desired product. Typical contents are between 5 and 50% by weight, preferably between 10 and 40% by weight and more preferably between 15 and 35% by weight, based on the tablet as a whole.
The content of bleaching agents in the tablets is again dependent on the application envisaged for the tablets. Whereas typical heavy-duty detergents in tablet form contain between 5 and 30% by weight, preferably between 7.5 and :?0 25% by weight and more preferably between 12.5 and 22.5% by weight of bleaching agent, bleach or bleach booster tablets contain between 15 and 50%
by weight, preferably between 22.5 and 45% by weight and more preferably between 30 and 40% by weight of bleaching agent.
According to the invention, particularly preferred bleaching agents are :?5 sodium perborate and sodium percarbonate, sodium perborate monohydrate being particularly preferred.
In addition to the bleaching agent, the cleaning tablets according to the invention may contain bleach activator(s). Bleach activators are incorporated in detergents in order to obtain an improved bleaching effect at washing temperatures of 60°C or lower. Compounds which form aliphatic peroxocarboxy-lic acids preferably containing 1 to 10 carbon atoms and more preferably 2 to carbon atoms and/or optionally substituted perbenzoic acid under perhydrolysis conditions may be used as bleach activators. Suitable bleach activators are substances which contain O- and/or N-acyl groups with the number of carbon atoms indicated and/or optionally substituted benzoyl groups. Preferred bleach activators are polyacylated alkylenediamines, more especially tetraacetyl ethylenediamine (TAED), acylated triazine derivatives, more particularly 1,5-diacetyl-2,4-dioxohexahydro-1,3,5-triazine (DADHT), acylated glycol urils, more particularly tetraacetyl glycol uril (TAGU), N-acylimides, more particularly N-nonanoyl succinimide (NOSI), acylated phenol sulfonates, more particularly n-nonanoyl- or isononanoyl-oxybenzenesulfonate (n- or iso-NOBS), carboxylic anhydrides, more especially phthalic anhydride, acylated polyhydric alcohols, more especially triacetin, ethylene glycol diacetate and 2,5-diacetoxy-2,5-dihydrofuran.
In addition to or instead of the conventional bleach activators, so-called bleach catalysts may also be incorporated in the tablets. Bleach catalysts are bleach-boosting transition metal salts or transition metal complexes such as, for example, Mn-, Fe-, Co-, Ru- or Mo-salen complexes or carbonyl complexes. Mn-, :?0 Fe-, Co-, Ru-, Mo-, Ti-, V- and Cu-complexes with N-containing tripod ligands and Co-, Fe-, Cu- and Ru-ammine complexes may also be used as bleach catalysts.
The tablets according to the invention contain between 0.5 and 30% by weight, preferably between 1 and 20% by weight and more preferably between 2 :?5 and 15% by weight, based on the tablet as a whole, of one or more bleach activators or bleach catalysts. These quantities may vary according to the application envisaged for the cleaning tablets. Thus, in typical heavy-duty detergent tablets, bleach activator contents of 0.5 to 10% by weight, preferably between 2 and 8% by weight and more preferably between 4 and 6% by weight are normal whereas bleach tablets contain much larger amounts, for example between 5 and 30% by weight, preferably between 7.5 and 25% by weight and more preferably between 10 and 20% by weight. The expert is not restricted in his freedom of formulation and can thus produce laundry detergent tablets, cleaner tablets or bleach tablets with a relatively strong or weak bleaching effect by varying the contents of bleach activator and bleaching agent.
A particularly preferred bleach activator is N,N,N',N'-tetraacetyl ethylenediamine which is widely used in detergents. Accordingly, preferred cleaning tablets are characterized in that tetraacetyl ethylenediamine in the quantities mentioned above is used as bleach activator.
Besides the ingredients mentioned, the cleaning tablets according to the invention may contain other ingredients in quantities determined by the application envisaged for the tablets. Thus, substances from the group of surfactants, builders and polymers are particularly suitable for use in the cleaning tablets according to the invention. The expert will again have no difficulty in selecting the individual components and the quantities in which to use them.
For example, a heavy-dcty detergent tablet will contain relatively large quantities of surfactants) whereas a bleaching tablet may even contain no surfactant at all.
The quantity of builders) used also varies according to the intended application.
:?0 The cleaning tablets according to the invention may contain any of the builders typically used in detergents and cleaners, i.e. in particular zeolites, silicates, carbonates, organic cobuilders and - providing there are no ecological objections to their use - also the phosphates.
Suitable crystalline layered sodium silicates correspond to the general :?5 formula NaMSiX02X+~y H20, where M is sodium or hydrogen, x is a number of 1.9 to 4 and y is a number of 0 to 20, preferred values for x being 2, 3 or 4.
Crystalline layered silicates such as these are described, for example, in European patent application EP-A-0 164 514. Preferred crystalline layered silicates corresponding to the above formula are those in which M is sodium and ' CA 02315298 2000-08-17 x assumes the value 2 or 3. Both Vii- and 8-sodium disilicates Na2Si205y H20 are particularly preferred, ~3-sodium disilicate being obtainable, for example, by the process described in International patent application WO-A- 91108171.
Other useful builders are amorphous sodium silicates with a modulus (Na20:Si02 ratio) of 1:2 to 1:3.3, preferably 1:2 to 1:2.8 and more preferably 1:2 to 1:2.6 which dissolve with delay and exhibit multiple wash cycle properties.
The delay in dissolution in relation to conventional amorphous sodium silicates can have been obtained in various ways, for example by surface treatment, compounding, compacting or by overdrying. In the context of the invention, the term "amorphous" is also understood to encompass "X-ray amorphous". In other words, the silicates do not produce any of the sharp X-ray reflexes typical of crystalline substances in X-ray diffraction experiments, but at best one or more maxima of the scattered X-radiation which have a width of several degrees of the diffraction angle. However, particularly good builder properties may even be achieved where the silicate particles produce crooked or even sharp diffraction maxima in electron diffraction experiments. This may be interpreted to mean that the products have microcrystalline regions between 10 and a few hundred nm in size, values of up to at most 50 nm and, more particularly, up to at most 20 nm being preferred. So-called X-ray amorphous silicates such as these, which also :?0 dissolve with delay in relation to conventional waterglasses, are described for example in German patent application DE-A-44 00 024. Compacted amorphous silicates, compounded amorphous silicates and overdried X-ray-amorphous silicates are particularly preferred.
The finely crystalline, synthetic zeolite containing bound water used in ?5 accordance with the invention is preferably zeolite A and/or zeolite P.
Zeolite MAP~ (Crosfield) is a particularly preferred P-type zeolite. However, zeolite X
and mixtures of A, X and/or P are also suitable. According to the invention, it is preferred to use, for example, a commercially obtainable co-crystallizate of zeolite X and zeolite A (ca. 80% by weight zeolite X) which is marketed by CONDEA Augusta S.p.A. under the name of VEGOBOND AXO and which may be described by the following formula:
nNa20 ~ (1-n)K20 ~ AI203 ~ (2 - 2.5)Si02 ~ (3.5 - 5.5) H20.

The zeolite may be used both as a builder in a granular compound and for "powdering" the entire mixture to be tabletted, both these options normally being used to incorporate the zeolite in the premix. Suitable zeolites have a mean particle size of less than 10 ~m (volume distribution, as measured by the Coulter 5 Counter Method) and contain preferably 18 to 22% by weight and more preferably 20 to 22% by weight of bound water.
The generally known phosphates may of course also be used as builders providing their use should not be avoided on ecological grounds. The sodium salts of the orthophosphates, the pyrophosphates and especially the 10 tripolyphosphates are particularly suitable.
The quantity of builder is normally between 10 and 70% by weight, preferably between 15 and 60% by weight and more preferably between 20 and 50% by weight. The quantity of builders used is again dependent on the intended application so that bleach tablets can contain larger quantities of builders (for example between 20 and 70% by weight, preferably between 25 and 65% by weight and more preferably between 30 and 55% by weight) than, for example, detergent tablets (normally 10 to 50% by weight, preferably 12.5 to 45% by weight and more preferably between 17.5 and 37.5% by weight).
Useful organic builders are, for example, the polycarboxylic acids usable, :?0 for example, in the form of their sodium salts, such as citric acid, adipic acid, succinic acid, glutaric acid, tartaric acid, benzene hexacarboxylic acid, sugar acids, for example gluconic acid, aminocarboxylic acids, nitrilotriacetic acid (NTA), providing its use is not ecologically unsafe, and mixtures thereof.
Preferred salts are the salts of the polycarboxylic acids, such as citric acid, adipic ?5 acid, succinic acid, glutaric acid, tartaric acid, sugar acids and mixtures thereof.
Preferred cleaning tablets additionally contain one or more surfactant(s).
Anionic, nonionic, cationic and/or amphoteric surfactants and mixtures thereof may be used in the cleaning tablets according to the invention.
Mixtures of anionic and nonionic surfactants are preferred from the performance perspective. The total surfactant content of the tablets is between 5 and 60%
by weight, based on tablet weight, surfactant contents above 15% by weight being preferred.
Suitable anionic surfactants are, for example, those of the sulfonate and sulfate type. Suitable surfactants of the sulfonate type are preferably C~~3 alkyl benzenesulfonates, olefin sulfonates, i.e. mixtures of alkene and hydroxyalkane sulfonates, and the disulfonates obtained, for example, from C~2_~$
monoolefins with an internal or terminal double bond by sulfonation with gaseous sulfur trioxide and subsequent alkaline or acidic hydrolysis of the sulfonation products.
Other suitable surfactants of the sulfonate type are the alkane sulfonates obtained from C~2_~$ alkanes, for example by sulfochlorination or sulfoxidation and subsequent hydrolysis or neutralization. The esters of a-sulfofatty acids (ester sulfonates), for example the a-sulfonated methyl esters of hydrogenated coconut, palm kernel or tallow fatty acids, are also suitable.
Other suitable anionic surfactants are sulfonated fatty acid glycerol esters.
Fatty acid glycerol esters in the context of the present invention are the monoesters, diesters and triesters and mixtures thereof which are obtained where production is carried out by esterification of a monoglycerol with 1 to moles of fatty acid or in the transesterification of triglycerides with 0.3 to 2 moles :?0 of glycerol. Preferred sulfonated fatty acid glycerol esters are the sulfonation products of saturated fatty acids containing 6 to 22 carbon atoms, for example caproic acid, caprylic acid, capric acid, myristic acid, lauric acid, palmitic acid, stearic acid or behenic acid.
Preferred alk(en)yl sulfates are the alkali metal salts and, in particular, the sodium salts of the sulfuric acid semiesters of C~2_~8 fatty alcohols, for example coconut alcohol, tallow alcohol, lauryl, myristyl, cetyl or stearyl alcohol, or C~o_2o oxoalcohols and the corresponding semiesters of secondary alcohols with the same chain length. Other preferred alk(en)yl sulfates are those with the chain length mentioned which contain a synthetic, linear alkyl chain based on a petrochemical and which are similar in their degradation behavior to the corresponding compounds based on oleochemical raw materials. C~Z_~6 alkyl sulfates, C~2_~5 alkyl sulfates and C~a_~5 alkyl sulfates are preferred from the point of view of washing technology. Other suitable anionic surfactants are 2,3-alkyl sulfates which may be produced, for example, in accordance with US 3,234,258 or US 5,075,041 and which are commercially obtainable as products of the Shell Oil Company under the name of DAN~.
The sulfuric acid monoesters of linear or branched C~_2~ alcohols ethoxylated with 1 to 6 moles of ethylene oxide, such as 2-methyl-branched Cg~~
alcohols containing an average 3.5 moles of ethylene oxide (EO) or C~2_~g fatty alcohols containing 'I to 4 EO, are also suitable. In view of their high foaming capacity, they are only used in relatively small quantities, for example in quantities of 1 to 5% by weight, in dishwashing detergents.
Other suitable anionic surfactants are the salts of alkyl sulfosuccinic acid which are also known as sulfosuccinates or as sulfosuccinic acid esters and which represent monoesters and/or diesters of sulfosuccinic acid with alcohols, preferably fatty alcohols and, more particularly, ethoxylated fatty alcohols.
Preferred sulfosuccinates contain C&~$ fatty alcohol residues or mixtures thereof.
Particularly preferred sulfosuccinates contain a fatty alcohol residue derived from :?0 ethoxylated fatty alcohols which, considered in isolation, represent nonionic surfactants (for a description, see below). Of these sulfosuccinates, those of which the fatty alcohol residues are derived from narrow-range ethoxylated fatty alcohols are particularly preferred. Alk(en)yl succinic acid preferably containing 8 to 18 carbon atoms in the alk{en)yl chain or salts thereof may also be used.
:?5 Other suitable anionic surfactants are, in particular, soaps. Suitable soaps are saturated fatty acid soaps, such as the salts of lauric acid, myristic acid, palmitic acid, stearic acid, hydrogenated erucic acid and behenic acid, and soap mixtures derived in particular from natural fatty acids, for example coconut oil, palm kernel oil or tallow fatty acids.

The anionic surfactants, including the soaps, may be present in the form of their sodium, potassium or ammonium salts and as soluble salts of organic bases, such as mono-, di- or triethanolamine. The anionic surfactants are preferably present in the form of their sodium or potassium salts and, more preferably, in the form of their sodium salts.
Preferred nonionic surfactants are alkoxylated, advantageously ethoxylated, more especially primary alcohols preferably containing 8 to 18 carbon atoms and, on average, 1 to 12 moles of ethylene oxide (EO) per mole of alcohol, in which the alcohol radical may be linear or, preferably, methyl-branched in the 2-position or may contain linear and methyl-branched radicals in the form of the mixtures typically present in oxoalcohol radicals. However, alcohol ethoxylates containing linear radicals of alcohols of native origin with 12 to 18 carbon atoms, for example coconut oil, palm oil, tallow or oleyl alcohol, and on average 2 to 8 EO per mole of alcohol are particularly preferred. Preferred ethoxylated alcohols include, for example, C~2_~4 alcohols containing 3 EO or EO, C9_» alcohol containing 7 EO, C~3_~5 alcohols containing 3 EO, 5 EO, 7 EO
or 8 EO, C~2-~s alcohols containing 3 EO, 5 EO or 7 EO and mixtures thereof, such as mixtures of C~2_~4 alcohol containing 3 EO and C~2_~8 alcohol containing 5 EO.
:?0 The degrees of ethoxylation mentioned represent statistical mean values which, for a special product, can be a whole number or a broken number. Preferred alcohol ethoxylates have a narrow homolog distribution (narrow range ethoxylates, NRE). In addition to these nonionic surfactants, fatty alcohols containing more than 12 EO may also be used, examples including tallow fatty alcohol containing 14 EO, 25 EO, 30 EO or 40 EO.
In addition, alkyl glycosides corresponding to the general formula RO(G)X
where R is a primary linear or branched, more particularly 2-methyl-branched, aliphatic radical containing 8 to 22 and preferably 12 to 18 carbon atoms and G
stands for a glycose unit containing 5 or 6 carbon atoms, preferably glucose, may be used as further nonionic surfactants. The degree of oligomerization x, which indicates the distribution of monoglycosides and oligoglycosides, is a number between 1 and 10; x preferably has a value of 1.2 to 1.4.
Another class of preferred nonionic surfactants which may be used either as sole nonionic surfactant or in combination with other nonionic surfactants are alkoxylated, preferably ethoxylated or ethoxylated and propoxylated, fatty acid alkyl esters preferably containing 1 to 4 carbon atoms in the alkyl chain, more especially the fatty acid methyl esters which are described, for example, in Japanese patent application JP 58/217598 or which are preferably produced by the process described in International patent application WO A-90113533.
Nonionic surfactants of the amine oxide type, for example N-cocoalkyl-N,N-dimethylamine oxide and N-tallowalkyl-N,N-dihydroxyethylamine oxide, and the fatty acid alkanolamide type are also suitable. The quantity in which these nonionic surfactants are used is preferably no more than the quantity in which the ethoxylated fatty alcohols are used and, more preferably, no more than half that quantity.
Other suitable surfactants are polyhydroxyfatty acid amides corresponding to formula (I):
R' R-CO-N-(Z] (I ) in which RCO is an aliphatic acyl group containing 6 to 22 carbon atoms, R' is hydrogen, an alkyl or hydroxyalkyl group containing 1 to 4 carbon atoms and [Z]
is a linear or branched polyhydroxyalkyl group containing 3 to 10 carbon atoms and 3 to 10 hydroxyl groups. The polyhydroxyfatty acid amides are known substances which may normally be obtained by reductive amination of a reducing sugar with ammonia, an alkylamine or an alkanolamine and subsequent acylation ;30 with a fatty acid, a fatty acid alkyl ester or a fatty acid chloride.

The group of polyhydroxyfatty acid amides also includes compounds corresponding to formula (II):
R'-O-R2 R-CO-N-[Z] (I I ) in which R is a linear or branched alkyl or alkenyl group containing 7 to 12 carbon atoms, R' is a linear, branched or cyclic alkyl group or an aryl group containing 2 10 to 8 carbon atoms and R2 is a linear, branched or cyclic alkyl group or an aryl group or an oxyalkyl group containing 1 to 8 carbon atoms, C~.~ alkyl or phenyl groups being preferred, and [Z] is a linear polyhydroxyatkyl group, of which the alkyl chain is substituted by at least two hydroxyl groups, or alkoxylated, preferably ethoxylated or propoxylated, derivatives of that group.

15 [Z] is preferably obtained by reductive amination of a reduced sugar, for example glucose, fructose, maltose, lactose, galactose, mannose or xylose. The N-alkoxy- or N-aryloxy-substituted compounds may then be converted into the required polyhydroxyfatty acid amides by reaction with fatty acid methyl esters in the presence of an alkoxide as catalyst, for example in accordance with the :?0 teaching of International patent application WO-A-95107331.
According to the invention, preferred cleaning tablets are those containing anionic and nonionic surfactant(s). Performance-related advantages can arise out of certain quantity ratios in which the individual classes of surfactants are used.
For example, particularly preferred cleaning tablets are characterized in that the ratio of anionic surfactants) to nonionic surfactants) is from 10:1 to 1:10, preferably from 7.5:1 to 1:5 and more preferably from 5:1 to 1:2.
It can be of advantage from the performance point of view if certain classes of surfactants are missing from certain phases of the cleaning tablets or ~:0 from the entire tablet, i.e. from every phase. In another important embodiment of the present invention, therefore, at least one phase of the cleaning tablets is free from nonionic surfactants.
Conversely, a positive effect can also be obtained through the presence of certain surfactants in individual phases or in the cleaning tablet as a whole, i.e. in every phase. Introducing the alkyl polyglycosides described above has proved to be of particular advantage, so that cleaning tablets in which at least one phase of the tablet contains alkyl polyglycosides are preferred.
As with the nonionic surfactants, the omission of anionic surfactants from individual phases or from all phases can result in cleaning tablets which are more suitable for certain applications. Accordingly, cleaning tablets where at least one phase of the tablet is free from anionic surfactants are also possible in accordance with the present invention.
In order to facilitate the disintegration of heavily cleaning compacted tablets, disintegration aids, so-called tablet disintegrators, may be incorporated in them to shorten their disintegration times. According to Rompp (9th Edition, Vol. 6, page 4440) and Voigt "Lehrbuch der pharmazeutischen Technologie"
(6th Edition, 1987, pages 182-184), tablet disintegrators or disintegration accelerators are auxiliaries which promote the rapid disintegration of tablets in water or gastric juices and the release of the pharmaceuticals in an absorbable form.
These substances, which are also known as "disintegrators" by virtue of their effect, are capable of undergoing an increase in volume on contact with water so that, on the one hand, their own volume is increased (swelling) and, on the other hand, a pressure can be generated through the release of gases which causes the tablet to disintegrate into relatively small particles. Well-known disintegration aids are carbonate/citric acid systems, although other organic acids may also be used. Swelling disintegration aids are, for example, synthetic polymers, such as polyvinyl pyrrolidone (PVP), or natural polymers and modified natural substances, such as cellulose and starch and derivatives thereof, alginates or casein derivatives.
Preferred cleaning tablets contain 0.5 to 10% by weight, preferably 3 to 7% by weight and more preferably 4 to 6% by weight of one or more disintegration aids, based on tablet weight.
According to the invention, preferred disintegrators are cellulose-based disintegrators, so that preferred cleaning tablets contain a cellulose-based disintegrator in quantities of 0.5 to 10% by weight, preferably 3 to 7% by weight and more preferably 4 to 6% by weight. Pure cellulose has the formal empirical composition (CsH~pO5)n and, formally, is a ~i-1,4-polyacetal of cellobiose which, in turn, is made up of two molecules of glucose. Suitable celluloses consist of ca.
500 to 5000 glucose units and, accordingly, have average molecular weights of 50,000 to 500,000. According to the invention, cellulose derivatives obtainable from cellulose by polymer-analog reactions may also be used as cellulose-based disintegrators. These chemically modified celluloses include, for example, products of esterification or etherification reactions in which hydroxy hydrogen atoms have been substituted. However, celluloses in which the hydroxy groups have been replaced by functional groups that are not attached by an oxygen atom may also be used as cellulose derivatives. The group of cellulose :?0 derivatives includes, for example, alkali metal celluloses, carboxymethyl cellulose (CMC), cellulose esters and ethers and aminocelluloses. The cellulose derivatives mentioned are preferably not used on their own, but rather in the form of a mixture with cellulose as cellulose-based disintegrators. The content of cellulose derivatives in mixtures such as these is preferably below 50% by weight and more preferably below 20% by weight, based on the cellulose-based disintegrator. In one particularly preferred embodiment, pure cellulose free from cellulose derivatives is used as the cellulose-based disintegrator.
The cellulose used as disintegration aid is preferably not used in fine-particle form, but is converted into a coarser form, for example by granulation or compacting, before it is added to and mixed with the premixes to be tabletted.
Detergent tablets which contain granular or optionally co-granulated disintegrators are described in German patent applications DE 197 09 991 (Stefan Herzog) and DE 197 10 254 (Henkel) and in International patent application PCT/EP98101203 (Henkel). Further particulars of the production of granulated, compacted or co-granulated cellulose disintegrators can also be found in these patent applications. The particle sizes of such disintegration aids are mostly above 200 Nm, preferably at least 90% by weight of the particles being between 300 and 1600 Nm in size and, more particularly, between 400 and 1200 Nm in size. According to the invention, the above-described relatively coarse-particle cellulose-based disintegrators described in detail in the cited patent applications are preferably used as disintegration aids and are commercially obtainable, for example under the name of Arbocel~ TF-30-HG from Rettenmaier.
Microcrystalline cellulose may be used as another cellulose-based disintegration aid or as part of such a component. This microcrystalline cellulose is obtained by partial hydrolysis of celluloses under conditions which only attack and completely dissolve the amorphous regions (ca. 30% of the total cellulose mass) of the celluloses, but leave the crystalline regions (ca. 70%) undamaged.
:?0 Subsequent de-aggregation of the microfine celluloses formed by hydrolysis provides the microcrystalline celluloses which have primary particle sizes of ca. 5 pm and which can be compacted, for example, to granules with a mean particle size of 200 Nm.
Cleaning tablets additionally containing a disintegration aid preferably based on cellulose, preferably in granular, cogranulated or compacted form, in quantities of 0.5 to 10% by weight, preferably in quantities of 3 to 7% by weight and more preferably in quantities of 4 to 6% by weight, based on tablet weight, represent a particularly preferred embodiment of the invention.
Besides the constituents mentioned - bleaching agent, bleach activator, builder, surfactant and disintegration aid - the cleaning tablets according to the invention may contain other typical ingredients of washing/cleaning compositions from the group of dyes, perfumes, optical brighteners, enzymes, foam inhibitors, silicone oils, redeposition inhibitors, discoloration inhibitors, dye transfer inhibitors and corrosion inhibitors.
In order to improve their aesthetic impression, the cleaning tablets according to the invention may be colored with suitable dyes. Preferred dyes, which are not difficult for the expert to choose, have high stability in storage, are not affected by the other ingredients of the detergents or by light and do not have any pronounced substantivity for textile fibers so as not to color them.
Any dyes which can be destroyed by oxidation in the washing process and mixtures thereof with suitable blue dyes, so-called blueing agents, are preferably used in the cleaning tablets according to the invention. It has proved to be of advantage to use dyes which are soluble in water or - at room temperature - in liquid organic substances. Suitable dyes are, for example, anionic dyes, for example anionic nitroso dyes. One possible dye is, for example, naphthol green (Color Index (CI) Part 1: Acid Green 1; Part 2: 10020), which is commercially available for example as BasacidO Grun 970 from BASF, Ludwigshafen, and mixtures thereof with suitable blue dyes. Other suitable dyes are Pigmosol~
Blau .?0 6900 (CI 74160), Pigmosol~ Grun 8730 (CI 74260), Basonyl~ Rot 545 FL (CI
45170), Sandolan~ Rhodamin EB 400 (CI 45100), Basacid~ Gelb 094 (CI
47005), Sicovit~ Patentblau 85 E 131 (CI 42051 ), Acid Blue 183 (CAS 12217-22-0, CI Acid Blue 183)., Pigment Blue 15 (CI 74160), Supranol~ Blau GLW (CAS
12219-32-8, CI Acid Blue 221), Nylosan~ Gelb N-7GL SGR (CAS 61814-57-1, CI
Acid Yellow 218) and/or Sandolan~ Blau (CI Acid Blue 182, CAS 12219-26-0).
In selecting the dye, it is important to ensure that the dye does not have an excessive affinity for the textile surfaces and, in particular, for synthetic fibers.
Another factor to be taken into account in the selection of suitable dyes is that dyes differ in their stability to oxidation. Generally speaking, water-insoluble dyes are more stable to oxidation than water-soluble dyes. The concentration of the dye in the detergents varies according to its solubility and hence its sensitivity to oxidation. In the case of readily water-soluble dyes, for example the above-mentioned Basacid~ Grun and Sandolan~ Blau, dye concentrations in the range 5 from a few 10-2 to 10'3 % by weight are typically selected. By contrast, in the case of the pigment dyes which are particularly preferred for their brilliance, but which are less readily soluble in water, for example the above-mentioned Pigmosol~ dyes, suitable concentrations of the dye in cleaners or laundry detergents are typically of the order of a few 10'3 to 10~ % by weight.
10 The tablets may contain optical brighteners selected from derivatives of diaminostilbenedisulfonic acid or alkali metal salts thereof as oxidation-sensitive substances. Suitable optical brighteners are, for example, salts of 4,4'-bis-(2-anilino-4-morpholino-1,3,5-triazinyl-6-amino)-stilbene-2,2'-disulfonic acid or compounds of similar structure which composition which contain a diethan-15 olamino group, a methylamino group, an anilino group or a 2-methoxyethylamino group instead of the morpholino group. Brighteners of the substituted diphenyl styryl type, for example alkali metal salts of 4,4'-bis-(2-sulfostyryl)-diphenyl, 4,4'-bis-(4-chloro-3-sulfostyryl)-Biphenyl or 4-(4-chlorostyryl)-4'-(2-sulfostyryl)-diphen-yl, may also be present. Mixtures of the brighteners mentioned above may also :?0 be used. The optical brighteners are used in the cleaning tablets according to the invention in concentrations of 0.01 tot % by weight, preferably in concentrations of 0.05 to 0.5% by weight and more preferably in concentrations of 0.1 to 0.25%
by weight, based on the tablet as a whole.
Perfumes are added to the cleaning tablets according to the invention to improve the aesthetic impression created by the products and to provide the consumer not only with the required washing performance but also with a visually and sensorially "typical and unmistakable" product. Suitable perfume oils or fragrances include individual perfume compounds, for example synthetic products of the ester, ether, aldehyde, ketone, alcohol and hydrocarbon type.

Perfume compounds of the ester type are, for example, benzyl acetate, phenoxyethyl isobutyrate, p-tert.butyl cyclohexyl acetate, linalyl acetate, dimethyl benzyl carbinyl acetate, phenyl ethyl acetate, linalyl benzoate, benzyl formate, ethyl methyl phenyl glycinate, allyl cyclohexyl propionate, styrallyl propionate and benzyl salicylate. 'The ethers include, for example, benzyl ethyl ether; the aldehydes include, for example, the linear alkanals containing 8 to 18 carbon atoms, citral, citronellal, citronellyloxyacetaldehyde, cyclamen aldehyde, hydroxycitronellal, lilial and bourgeonal; the ketones include, for example, the ionones, a-isomethyl ionone and methyl cedryl ketone; the alcohols include anethol, citronellol, eugenol, geraniol, linalool, phenyl ethyl alcohol and terpineol and the hydrocarbons include, above all, the terpenes, such as limonene and pinene. However, mixtures of various perfumes which together produce an attractive perfume note are preferably used. Perfume oils such as these may also contain natural perfume mixtures obtainable from vegetable sources, for example pine, citrus, jasmine, patchouli, rose or ylang-ylang oil. Also suitable are clary oil, camomile oil, clove oil, melissa oil, mint oil, cinnamon leaf oil, lime blossom oil, juniper berry oil, vetiver oil, olibanum oil, galbanum oil and labdanum oil and orange blossom oil, neroli oil, orange peel oil and sandalwood oil.
The perfume content of the cleaning tablets according to the invention is :?0 normally up to 2% by weight of the formulation as a whole. The perfumes may be directly incorporated in the tablets according to the invention, although it can also be of advantage to apply the perfumes to supports which strengthen the adherence of the perfume to the washing and which provide the textiles with a long-lasting fragrance through a slower release of the perfume. Suitable support :?5 materials are, for example, cyclodextrins, the cyclodextrin/perfume complexes optionally being coated with other auxiliaries.
Suitable enzymes are those from the class of proteases, lipases, amylases, cellulases or mixtures thereof. Enzymes obtained from bacterial strains or fungi, such as Bacillus subtilis, Bacillus licheniformis and Streptomyces griseus, are particularly suitable. Proteases of the subtilisin type are preferred, proteases obtained from Bacillus lentus being particularly preferred. Enzyme mixtures, for example of protease and amylase or protease and lipase or protease and cellulase or of cellulase and lipase or of protease, amylase and lipase or of protease, lipase and cellulase, but especially cellulase-containing mixtures, are of particular interest. Peroxidases or oxidases have also proved to be suitable in some cases. The enzymes may be adsorbed to supports and/or encapsulated in membrane materials to protect them against premature decomposition. The percentage content of the enzymes, enzyme mixtures or 't 0 enzyme granules in the tablets according to the invention may be, for example, from about 0.1 to 5% by weight and is preferably from 0.1 to about 2% by weight.
In addition, the cleaning tablets according to the invention may also contain components with a positive effect on the removal of oil and fats from textiles by washing (so-called soil repellents). This effect becomes particularly clear when a textile which has already been repeatedly washed with a detergent according to the invention containing this oil- and fat-dissolving component is soiled. Preferred oil- and fat-dissolving components include, for example, nonionic cellulose ethers, such as methyl cellulose and methyl hydroxypropyl cellulose containing 15 to 30% by weight of methoxyl groups and 1 to 15% by weight of hydroxypropoxyl groups, based on the nonionic cellulose ether, and the polymers of phthalic acid and/or terephthalic acid known from the prior art or derivatives thereof, more particularly polymers of ethylene terephthalates and/or polyethylene glycol terephthalates or anionically and/or nonionically modified derivatives thereof. Of these, the sulfonated derivatives of phthalic acid and terephthalic acid polymers are particularly preferred.
Cleaning tablets are produced by the application of pressure to a mixture to be tabletted which is accommodated in the cavity of a press. In the most simple method of tablet production - hereinafter referred to simply as tabletting -the mixture to be tabletted is compressed directly, i.e. without preliminary granulation. The advantages of this so-called direct tabletting are its simple and inexpensive application because no other process steps and hence no other items of equipment are involved. However, these advantages are offset by disadvantages. Thus, a powder mixture which is to be directly tabletted must possess adequate plastic deformability and good flow properties and must not show any tendency to separate during storage, transportation and filling of the die. Unfortunately, these three requirements are very difficult to satisfy with many mixtures so that direct tabletting is often not applied, particularly in the production of cleaning tablets. Accordingly, the normal method of producing detergent tablets starts out from powder-form components ("primary particles") which are agglomerated or granulated by suitable methods to secondary particles with larger particle diameters. These granules or mixtures of different granules are then mixed with individual powder-form additives and the resulting mixtures are tabletted.
According to the invention, preferred cleaning tablets are obtained by tabletting particulate premixes of at least one batch of surfactant-containing granules and at least one subsequently added powder-form component. The surfactant-containing granules may be produced by conventional granulation processes, such as mixer and pan granulation, fluidized bed granulation, extrusion, pelleting or compacting. It is of advantage so far as the subsequent detergent tablets are concerned if the premixes to be tabletted have a bulk density approaching that of standard compact detergents. In one particularly preferred embodiment, the premix to be tabletted has a bulk density of at least 500 g/l, preferably of at least 600 g/l and more preferably above 700 g/l.
Another .?5 advantage can arise out of a relatively narrow particle size distribution of the surfactant granules used. According to the invention, preferred cleaning tablets are those in which the granules have particle sizes of 10 to 4,000 Nm, preferably between 100 and 2,000 Nm and more preferably between 600 and 1,400 pm.
In another preferred embodiment, the components) subsequently incorporated contains) the bleaching agent in the particle size distribution according to the invention mentioned above.
Before the particulate premix is compressed to form detergent tablets, it may be "powdered" with fine-particle surface treatment materials. This can be of advantage to the quality and physical properties of both the premix (storage, tabletting) and the final cleaning tablets. Fine-particle powdering materials have been known for some time in the art, zeolites, silicates and other inorganic salts generally being used. However, the premix is preferably "powdered" with fine-particle zeolite, zeolites of the faujasite type being preferred. In the context of the present invention, the expression "zeolite of the faujasite type" encompasses all three zeolites which form the faujasite subgroup of zeolite structural group 4 (cf.
Donald W. Breck: "Zeolite Molecular Sieves" John Wiley & Sons, New York/London/Sydney/Toronto, 1974, page 92). Besides zeolite X, therefore, zeolite Y and faujasite and mixtures of these compounds may also be used, pure zeolite X being preferred.
Mixtures or co-crystallizates of faujasite zeolites with other zeolites, which do not have to belong to zeolite structural group 4, may also be used for powdering, in which case at least 50% by weight of the powdering material advantageously consists of a zeolite of the faujasite type.
:?0 According to the invention, preferred cleaning tablets consist of a particulate premix containing granular components and subsequently incorporated powder-form components, the, or one of the, fine-particle components subsequently incorporated being a zeolite of the faujasite type with particle sizes below 100 Nm, preferably below 10 Nm and more preferably below :?5 5 Nm and making up at least 0.2% by weight, preferably at least 0.5% by weight and more preferably more than 1 % by weight of the premix to be compressed.
The fine-particle aftertreatment components with the particle sizes mentioned above may be dry-mixed with the premix to be tabletted. However, it is also possible and preferred to "stick" them onto the surface of the relatively coarse particles by addition of small quantities of liquid components. These powdering techniques are widely described in the prior art literature and familiar to the expert. Liquid components suitable as adhesion promoters for the powdering materials are, for example, nonionic surfactants or aqueous solutions 5 of surfactants or other detergent ingredients. In one preferred embodiment of the invention, perfume is used as the liquid component for promoting adhesion between the powdering materials and the coarse particles.
To produce the tablets according to the invention, the premixes are compacted between two punches in a die to form a solid compactate. This '10 process, which is referred to in short hereinafter as tabletting, comprises four phases, namely metering, compacting (elastic deformation), plastic deformation and ejection.
The tabletting process is carried out in commercially available tablet presses which, in principle, may be equipped with single or double punches. In '15 the latter case, not only is the top punch used to build up pressure, the bottom punch also moves towards the top punch during the tabletting process while the top punch presses downwards. For small production volumes, it is preferred to use eccentric tablet presses in which the punches) is/are fixed to an eccentric disc which, in turn, is mounted on a shaft rotating at a certain speed. The 20 movement of these punches is comparable with the operation of a conventional four-stroke engine. Tabletting can be carried out with a top punch and a bottom punch, although several punches can also be fixed to a single eccentric disc, in which case the number of die bores is correspondingly increased. The throughputs of eccentric presses vary according to type from a few hundred to at ?5 most 3,000 tablets per hour.
For larger throughputs, rotary tablet presses are generally used. In rotary tablet presses, a relatively large number of dies is arranged in a circle on a so-called die table. The number of dies varies - according to model - between 6 and 55, although even larger dies are commercially available. Top and bottom punches are associated with each die on the die table, the tabletting pressures again being actively 'built up not only by the top punch or bottom punch, but also by both punches. The die table and the punches move about a common vertical axis, the punches being brought into the filling, compaction, plastic deformation and ejection positions by means of curved guide rails. At those places where the punches have to be raised or lowered to a particularly significant extent (filling, compaction, ejection;l, these curved guide rails are supported by additional push-down members, pull-down rails and ejection paths. The die is filled from a rigidly arranged feed unit, the so-called filling shoe, which is connected to a storage ~10 container for the compound. The pressure applied to the premix can be individually adjusted through the tools for the top and bottom punches, pressure being built up by the rolling of the punch shank heads past adjustable pressure rollers.
To increase throughput, rotary presses can also be equipped with two filling shoes so that only half a circle has to be negotiated to produce a tablet. To produce two-layer or multi-layer tablets, several filling shoes are arranged one behind the other without the lightly compacted first layer being ejected before further filling. Given suitable process control, shell and bull's-eye tablets -which have a structure resembling an onion skin - can also be produced in this way.
In .?0 the case of bull's-eye tablets, the upper surface of the core or rather the core layers is not covered and thus remains visible. Rotary tablet presses can also be equipped with single or multiple punches so that, for example, an outer circle with 50 bores and an inner circle with 35 bores can be simultaneously used for tabletting. Modern rotary tablet presses have throughputs of more than one ?5 million tablets per hour.
Tabletting machines suitable for step a) of the process according to the invention can be obtained, for example, from the following companies:
Apparatebau Holzwarth GbR, Asperg, Wilhelm Fette GmbH, Schwarzenbek, Hofer GmbH, Weil, KILIAN, Cologne, KOMAGE, Kell am See, KORSCH Pressen GmbH, Berlin, Mapag Maschinenbau AG, Bern (Switzerland) and Courtoy N.V., Halle (BE/LU). One example of a particularly suitable tabletting machine is the model HPF 630 hydraulic double-pressure press manufactured by LAEIS, D.
The tablets can be made in certain shapes and certain sizes, always consisting of several phases, i.e. layers, inclusions or cores and rings.
Suitable shapes are virtually any easy-to-handle shapes, for example slabs, bars, cubes, squares and corresponding shapes with flat sides and, in particular, cylindrical forms of circular or oval cross-section. This last embodiment encompasses shapes from tablets to compact cylinders with a height-to-diameter ratio of more '10 than 1.
The portioned pressings may be formed as separate individual elements which correspond to .a predetermined dose of the detergent/cleaner. However, it is also possible to form pressings which combine several such units in a single pressing, smaller portioned units being easy to break off in particular through the '15 provision of predetermined weak spots. For the use of laundry detergents in machines of the standard European type with horizontally arranged mechanics, it can be of advantage to produce the portioned pressings as cylindrical or square tablets, preferably with a diameter-to-height ratio of about 0.5:2 to 2:0.5.
Commercially available hydraulic presses, eccentric presses and rotary presses ?0 are particularly suitable for the production of pressings such as these.
The three-dimensional form of another embodiment of the tablets is adapted in its dimensions to the dispensing compartment of commercially available domestic washing machines, so that the tablets can be introduced directly, i.e. without a dosing aid, into the dispensing compartment where they 25 dissolve on contact with water. The cleaning tablets may of course also be used in conjunction with a dosing aid.
Another preferred multi-phase tablet which can be produced has a plate-like or slab-like structure with alternately thick long segments and thin short segments, so that individual segments can be broken off from this "bar" at the predetermined weak spots, which the short thin segments represent, and introduced into the machine. This "bar" principle can also be embodied in other geometric forms, for example vertical triangles which are only joined to one another at one of their longitudinal sides. In this case, it is appropriate for optical reasons to make the base of the triangle, by which the individual segments are interconnected, as one phase while the apex forms the second phase. In this embodiment, different coloring of the two phases is particularly attractive.
After pressing, the cleaning tablets have high stability. The fracture resistance of cylindrical tablets can be determined via the diametral fracture stress. This in turn can be determined in accordance with the following equation:

a=
~Dt where a represents the diametral fracture stress (DFS) in Pa, P is the force in N
which leads to the pressure applied to the tablet that results in fracture thereof, D
is the diameter of the tablet in meters and t is its height.
Examples To produce bleach-containing cleaning tablets, surfactant granules were :?0 mixed with other additive components and the resulting mixture tabletted in an eccentric tablet press. The bleaching agent (sodium perborate monohydrate) added via the additive components had different particle size distributions according to the tablet series. The composition of the surfactant granules is shown in Table 1 below while the composition of the premix to be tabletted (and hence the composition of the tablets) is set out in Table 2. Table 3 shows the particle size distributions of the perborate monohydrate used in the various tablets.
Table 1:
Surfactant granules [% by weight]

C9_,3 alkyl benzenesulfonate 18.4 C,2_,$ fatty alcohol sulfate 4.9 C,2_,$ fatty alcohol + CEO 4.9 Soap 1.6 Sodium carbonate 18.8 Sodium silicate 5.5 Zeolite A (water-free active 31.3 substance) Optical brightener 0.3 Na hydroxyethane-1,1-diphosphonate0.8 Acrylic acid/maleic acid copolymer5.5 Water, salts Balance Table 2:
Premix [% by weight]
Surfactant granules 62.95 Sodium perborate manohydrate17.00 Tetraacetyl ethylenediamine7.3 Foam inhibitor 3.5 Enzymes 2.5 Perfume 0.5 Zeolite A 1.0 Cellulose* 4.0 ~ compacted cellulose (particle size: 90% by weight > 400 Nm ~ Table 3:
Sodium perborate monohydrate - particle size distribution [% by weight]

>1.6mm <1 - - -> 0.8 mm 40-60 2 -> 0.4 mm 30-60 55 33 > 0.2 mm < 10 40 60 90 <0.2mm <1 <5 <8 10 Mean particle size 0.54-0.620.32 0.26 0.19 [mm]

The hardness of the tablets was measured by deforming a tablet until it broke, the force being applied to the sides of the tablet and the maximum force withstood by the tablet being determined.
To determine tablet disintegration, a tablet was placed in a glass beaker filled with water (600 ml water, temperature 30°C) and the time taken for the tablet to disintegrate completely was measured.
For the dispensing test, two tablets were placed in the dispensing compartment of a commercially available washing machine and the wash program was started. On completion of the dispensing phase, the dispensing compartment was removed from the machine and visually evaluated. If residues are clearly visible in the compartment, the tablets were judged to be non-dispensable.
The individual premixes were tabletted in an eccentric tablet press to form series of tablets. Two series of tablets differing in hardness were produced by varying the tabletting pressure.
The experimental data are set out in Table 4.
Table 4:
Detergent tablets [physical data]
Tablet E1 E1' C1 C1' C2 C2' C3 C3' Tablet hardness 25 35 25 35 25 35 25 35 [N]

Tablet disintegration6 10 18 55 24 70 35 63 [s]

Dispensable Yes Yes Yes No Yes No No No Besides their outstanding physical properties, tablets E1 and E1' according to the invention also show improve cleaning performance against enzymatically removable soils (egg, blood, cocoa).

Claims (28)

1. Cleaning tablets of compacted particulate detergent/cleaner comprising bleaching agent, builder(s) and optionally other ingredients of washing/cleaning compositions, wherein the bleaching agent has a mean particle size above 0.4 mm.

2. Cleaning tablets as claimed in claim 1, wherein the bleaching agent is substantially free from particles below 0.2 mm in size.

3. Cleaning tablets as claimed in claim 1 or 2, wherein the bleaching agent contains less than 30% by weight of particles below 0.4 mm in size.

4. Cleaning tablets as claimed in claim 3, wherein the bleaching agent contains less than 20% by weight of particles below 0.4 mm in size.

5. Cleaning tablets as claimed in claim 3, wherein the bleaching agent contains less than 10% by weight of particles below 0.4 mm in size.

6. Cleaning tablets as claimed in any of claims 1 to 5, wherein the bleaching agent contains more than 10% by weight of particles larger than 0.8 mm in size.

7. Cleaning tablets as claimed in claim 6, wherein the bleaching agent contains more than 20% by weight of particles larger than 0.8 mm in size.

8. Cleaning tablets as claimed in claim 6, wherein the bleaching agent contains more than 30% by weight of particles larger than 0.8 mm in size.

9. Cleaning tablets as claimed in any of claims 1 to 8, wherein the bleaching agent is substantially free from particles larger than 1.6 mm in size.

10. Cleaning tablets as claimed in any of claims 1 to 9, wherein sodium perborate or sodium percarbonate is the bleaching agent.

11. Cleaning tablets as claimed in claim 10, wherein sodium perborate monohydrate is the bleaching agent.

12. Cleaning tablets as claimed in any of claims 1 to 11, wherein there is additionally present one or more bleach activator(s).

13. Cleaning tablets as claimed in any of claims 1 to 12, wherein there is additionally present one or more surfactant(s).

14. Cleaning tablets as claimed in any of claims 1 to 13, wherein the tablets are obtained by tabletting a particulate premix of at least one type of surfactant-containing granules and at least one subsequently added powder-form component.

15. Cleaning tablets as claimed in claim 14, wherein the granules are produced by standard granulation processes such as mixer and pan granulation, fluidized bed granulation, extrusion, pelleting or compacting.

16. Cleaning tablets as claimed in claim 14 or 15, wherein the granules have particle sizes of 100 to 4000 µm.

17. Cleaning tablets as claimed in claim 14 or 15, wherein the granules have particle sizes in the range from 100 to 2000 µm.

18. Cleaning tablets as claimed in claim 14 or 15, wherein the granules have particle sizes in the range from 600 to 1400 µm.

19. Cleaning tablets as claimed in any of claims 14 to 18, wherein the powder-form component(s) subsequently added contain(s) the bleaching agent.

20. Cleaning tablets as claimed in any of claims 14 to 19, wherein the premix to be tabletted has a bulk density of at least 500 g/l.

21. Cleaning tablets as claimed in any of claims 14 to 19, wherein the premix to be tabletted has a bulk density of at least 600 g/l.

22. Cleaning tablets as claimed in any of claims 14 to 19, wherein the premix to be tabletted has a bulk density of at least 700 g/l.

23. Cleaning tablets as claimed in any of claims 1 to 19, wherein there is additionally present a disintegration aid in quantities of 0.5 to 10% by weight based on the weight of the tablets.

24. Cleaning tablets as claimed in claim 23, wherein the disintegration aid is a cellulose-based disintegration aid.

25. Cleaning tablets as claimed in claim 23 or 24, wherein the disintegration aid is in granular, co-granulated or compacted form.

26. Cleaning tablets as claimed in any of claims 23 to 25, wherein the disintegration aid is present in quantities of 3 to 7% by weight.

27. Cleaning tablets as claimed in any of claims 23 to 26, wherein the disintegration aid is present in quantities of 4 to 6% by weight.

28. Cleaning tablets as claimed in any of claims 1 to 27, wherein there is additionally present one or more substances selected from the group of enzymes, pH regulators, perfumes, perfume carriers, fluorescers, dyes, foam inhibitors, silicone oils, redeposition inhibitors, optical brighteners, discoloration inhibitors, dye transfer inhibitors and corrosion inhibitors.