CA2300638A1 - Washing and detergent moulded bodies with improved solubility - Google Patents

Abstract

The invention relates to washing and detergent moulded bodies with improved solubility, composed of washing and detergent compacted particulates containing one or more surfactants, additives, a cellulose based disintegration agent, and optionally other constituents of washing and detergent agents, in which all hydrophobic substances are applied to a support material.

Description

Washing and D~eterger~t Moulded Bodies with Improved Solubility This invention relatEa generally to compact shaped bodies (tablets) having detersive propertiEa. More particularly, the invention relates to detergent tablets such as, for example, laundry detergent tablets, dishwasher tablets, stain remover tablets or water softening tablets for use in the home, more particularly for use in machines.
Detergent tablets are widely described in the prior-art literature and are enjoying increasing popularity among consumers because they are easy to dose. Tabletted detergents have a number of advantages over powder-form detergents: they are easier to dose and handle and, by virtue of their compact structurE~, have advantages in regard to storage and transportation. As a result, detergent tablets are also comprehensively described in the patent literature. One problem which repeatedly arises in the use of detergent tablets is the inadequate disintegrating and dissolving rate of the tablets under in-use conditions. Since sufficiently stable, i.e.
dimensionally stable and fracture-resistant, tablets can only be produced by applying relatively high prEasures, the ingredients of the tablet are heavily compacted so that disintegration of the tablet in the wash liquor is delayed which results in e>;cessively slow release of the active substances in the washing process.
The problem of the overly long disintegration times of highly compacted tablets is known in particular from the pharmaceutical industry where certain disintegration aids, so-called tablet disintegrators, have been used for some time in ordE~r to shorten the disintegration times. According to Rompp (9th Edition, Vol. 6, page 4440) and Voigt "Lehrbuch der pharmazeutischen Tech~nologie" (6th Edition, 1987, pages 182-184), tablet disintegrators or disintegration accelerators are auxiliaries which provide for the rapid disintegration of tablets in water or gastric juices and for the release of the pharmaceutical principles in an absorbable form.
"Hagers Handbuc,h der pharmazeutischen Praxis" (5th Edition, 1991, page 942) classifies the disintegration accelerators or disintegrators according to their action imechanism, the most important action mechan isms being the swelling mechanism, the deformation mechanism, the wicking mechanism, the repulsion mechanism and the evolution of gas bubbles on contact with water (effervescent tablets). In the case of the swelling mechanism, the particles swell on contact with water and undergo an increase in volume. This produces local stresses which spread throughout the tablet and thus lead to disintegration of the compacted structure. The deformation mechanism differs from the swelling mechanism in the fact that the swelling particles were previously compressed during the tabletting process and now return to their original size on contact with water.. In the case of the wicking mechanism, water is drawn into the interior of the tablet by the disintegration accelerator and loosens the binding forcE~s between the particles which also results in disintegration of the tablet. The repulsion mechanism differs additionally in the fact that the particles released by the water drawn into the pores repel one another under the effect of the electrical forces generated. A totally different mechanisim forms the basis of "effervescent tablets" which contain active substances or actlive-substance systems which, on contact with water, release gases that cause the tablet to burst. In addition, it is known to use hydrophilicizing agents which provide for better wetting of the compressed particles in water and hence for faster disintegration.
Whereas substances which act by the last two of the above-mentioned mechanisms can easily be distinguished from other disintegration mechanismis, the effects on which the swelling and deformation mechanisms .and the wicking and repulsion mechanisms are based cannot always be clearly distinguished from one another, so that classification into hydrop~hilicizing agents, gas-releasing systems and swelling disintegrators is more appropriate for practical reasons.
In the case of the detergent tablets described in the prior art, the use of disintegration aids is generally explicitly described and the various classes of disintegration aids, such as starch and starch derivatives, cellulose and cellulose derivatives and, for example, polyvinyl pyrrolidone and other polymers are mentioned, although the incorporation of such substances is genE~rally not discussed in detail.
Thus, EP-A-0 522 766 (Unilever) discloses tablets of a compacted particulate detergent cornposition containing surfactants, builders and disintegration aids (for example based on cellulose), the particles being at least partly coated with the disintegration aid which acts both as a binder and as a disinteg~rator daring dissolution of the tablets in water. The document in question also refers to the general difficulty of producing tablets combining :adequai:e stability with good solubility. The particle size in the mixture to be tablelaed is said to be above 200 Nm, the upper and lower limits to the individual particle sizes differing by no more than 700 Nm from one another.
Other docurnents concerned with the production of detergent tablets are EP-A-0716 1414 (Unilever), which describes tablets with an external shell of water-soluble material, and EP-A-0 711 827 (Unilever), according to which one of the ingredients is a citrate with defined solubility.
The use of binder's optionally developing a disintegrating effect (more particularly polyethylene glycol) is disclosed in EP-A-0 711 828 (Unilever) which dE~scribes detergent tablets that are produced by tabletting a particulate detergent cornposition at temperatures between 28°C and the melting point of the binder, tabletting 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 t;ablettinct is carried out at elevated temperature.
Detergent i:ablets in which individual ingredients are present separate from others are also described in EP-A-O 481 793 (Unilever).
The detergent tablets disclosed in this document contain sodium percarbonate which is separated from all other components that could affect its stability.
Perfume tablets for perfuming fabrics in a washing machine, where perfumes are applied to carrier materials such as starches, silicas, silicates, phosphates, zeolites, polymeric polycarboxylates or polyaspartic acids, are known from DE 1915 30 999 (Henkel). The tablets containing 8 to 40% by weight perfume described in this document are used in a process for applying perfumes~~fragrances to fabrics.
None of the documf:nts cited above is concerned with improving the solubility of detergent tablets by selective modification or incorporation of hydrophobicizing constituents or the disintegration aid.
Accordingly, the problem addressed by the present invention was to provide detergent: tablets with further improved disintegration and dissolving properties by selective incorporation of the hydrophobicizing components.
The present invention relates to a detergent tablet of compacted particulate detergent containing surfactant(s), builders, a cellulose-based disintegration aid and optionally other detergent ingredients, all the hydro-phobicizing substances beiing applied to a carrier material.
The detergent tablets according to the present invention solve the problem of inadequate tablet disintegration through an inadequate disintegrating effect of the cellulose-based disintegration aid by application of the hydrophobicizing constituents, which can reduce the disintegrating effect by preventing the rapid access of water to all regions of the tablet, to a carver.
Without wanting to be limited in any way by this theory, applicants assume that the separation of the hydrophobicizing components from the other components makes it easier for water to reach the interior of the tablet, thereby accelerating tablet disintegration. Thus, hydrophobicizing substances are no longer distributed widely and substantially uniformly throughout the tak>let, but are located in demarcated regions so that it is easier for water to reach the interior of the tablet.

5 Preferred tablets acre not produced from a mixture of individual powders, but at least partly from compounds, i.e. a mixture of a few granules. The primary particles of the ingredients are agglomerated to secondary particle:; which in turn are compressed to tablets. It is crucial to the invention th<~t hydrophobicizing components are not uniformly distributed throughout the tablet, for example by being sprayed onto the granules, but are separately applied to a carrier material which is mixed with other powders or secondary agglomerates before the tabletting process. Since the production sequence is generally reversed in the dissolution of the tablets, i.e. the tablets first disintegrate into relatively coarse particles which then dissolve, rapid disintegration into individual particles and hence con~;iderable surface enlargement are essential to good solubility. BE~cause vthe hydrophobicizing components are applied to the carrier material, the indlividual particles of the tablet do not all come into contact with hydrophobicizing substance, so that the disintegration of the tablet into the individual granules takes place far more quickly. The individual particles formed in this way dissolve quickly in the same way as conventional detergent powders, even when individual particles contain hydrophobicizing substances. Surfactant compounds are preferably used as carrier material for the hydrophobicizing substances. These surfactant compounds may be free' from hydrophobicizing nonionic surfactants, although they may also contain hydrophobicizing nonionic surfactants and may be further impregnated with hydrophobicizing substances, for example perfume. In another preferred embodiment, the cellulose-based disintegrator is used a:, carrier material for the hydrophobicizing substances. Ho~nrever, any of the carrier materials typically used in detergents, such as zeolites, silicates, silicas, etc., may of course also be used as carrier materials for the hydrophobicizing substances. In one particularly preferred embodiment, the carrier material impregnated with hydrophobicizing substances is present in a demarcated region of the tablet, the demarcated region containing the carrier impregnated with hydrophobic substance preferably being in the form of a separate layer, a coating or individual insert:>.
Hydrophobicizing substances in the context of the present invention are understood to be substances which reduce the wettability of the tablet or rather constituentparticles with In particular, typically its water.

hydrophobic substances,such as paraffinsand silicones (used as defoamers in detergents)or perfume oils, mentioned as hydropho-are bicizing substance,. Other hydrophobicizing substances are, for example, nonionic surfactants which do not dissolve spontaneously in water, but tend to gel. Although not all nonionic surfactants have this hydrophobicizing character, a theoretical division into hydrophobicizing and non-hydro-phobicizing nonionic surfactants is difficult. The expert will have no difficulty in finding nonionic surfactants with an overly hydrophobicizing character and applying them to the carrier material. Reference points in this regard are, for example, the HLB values of the nonionic surfactants.
Nonionic surfactants with HLB values below 10 tend to be more hydrophobicizing while those with HLB values above 12 may be regarded as non-hydrophobicizing. In view of the general difficulties involved in theoretically predicting the hydrophobicizing character of nonionic surfac-tants, the nonionic surfacaants are all preferably applied to the carrier material. Preferred tablet, contain nonionic surfactants with HLB values below 10 applied to a carrier material as hydrophobicizing substances.
Application to the carrier material may be carried out, for example, by spraying on a solution or melt. However, introducing the nonionic surfactants in granulation processes where they form surfactant compounds with the carrier materials is another suitable method of apply-ing the carrier material.
Suitable foam inhibitors are, for example, soaps of natural or synthetic origin which have a high percentage content of C~$_24 fatty acids.
Suitable non-surface-active foam inhibitors are, for example, organo polysiloxanes and' mixtures thereof with microfine, optionally silanized, silica or bis-stearyl ethylenediamide. Mixtures of different foam inhibitors, for example mixtures of silicones, paraffins and waxes, may also be used with advantage. Nlixtures of paraffins and bis-stearyl ethylene diamides are particularly preferred. Where they are used in the tablets according to the invention, these foam inhibitors are applied to a .carrier material. Preferred detergent tablets contain foam inhibitors applied to a carrier material as a hydrophobicizing substance.
Dyes and fragrances are added to the detergent 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 vvith 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 estE~r type are, for example, benzyl acetate, phenoxyethyl isobutyrate, p-tert.butyl cyclohexyl acetate, linalyl acetate, dimethyl benzyl c<~rbinyl 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 ald~ehydes include, for example, the linear alkanals containing 8 to 18 carbon atoms, citral, citronellal, citronellyloxy-acetaldehyde, cyclamen aldehyde, hydroxycitronellal, lilial and bourgeonal;
the ketones inclucle, 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 detergE:nt tablets according to the invention normally contain less than 0.01 % by weight of dyes whereas perfumes/fragrances can make up as much as 2% by weight of the formulation as a whole.
Since the dyes used in detergents are generally readily soluble in water and are not absorbed by the treated fabric, they may even be distributed throughout the tablet. According to the invention, the perfumes which have a pronounced hydrophobicizing character should be applied to a carrier material. PreferrE:d detergent tablets contain perfume applied to a carrier material as a hydrophobicizing substance.
In the context of the present invention, disintegrators are understood to be cellulose-based disintegrators of which the disintegrating effect is distinctly improved by their presence in accordance with the invention in a demarcated region separate from hydrophobicizing substances. Pure cellulose has the formal empirical composition (C6H~o05)" and, formally, is a ~-1,4-polyacetal of cellobiose which, in turn, is made up of 2 molecules of glucose. Suitable celluloses consist of ca. 500 to 5000 glucose units and, accordingly, have averages molecular weights of 50,000 to 500,000. The cellulose may be agglomerated by granulation with other ingredients to form secondary granules with a larger particle size. The pre-granulation primary particle si~:es of the cellulose are preferably below 100 pm, more preferably below i'0 Nm and most preferably below 50 Nm. According to the invention, cellulose derivatives obtainable from cellulose by polymer-analog reactions may al o 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. Hlowever, celluloses in which the hydroxy groups have been replaced by functional groups that are not attached by an oxygen atom may also b~e used as cellulose derivatives. The group of cellulose derivatives includes, for example, alkali metal celluloses, carboxymethyl cE:llulose (CMC), cellulose esters and ethers and aminocelluloses.
The cellulose derivatives mentioned are preferably not used on their own, but rather in the forrn 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 embodinnent, pure cellulose free from cellulose derivatives is used as the cellulose-based disintegrator.
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. Subsequent de-aggregation of the micro fine celluloses formed by hydrolysis provides the microcrystalline celluloses which have primary parlricle sizes of ca. 5 Nm and which can be compacted, for example, to granules with a mean particle size of 200 Nm.
In the context of the present invention, cellulose-based disintegrators are also understood to be disintegrators which contain a mixture of cellulose or cellulose derivatives and other disintegrators providing the cellulose or cellulose derivative content exceeds 50% by weight, based on the disintegrator. With disintegrators such as these also, the separation of hydrophobicizing substances in accordance with the invention leads to a distinct improvement in the disintegrating effect.
5 Suitable swellable water-insoluble disintegration aids, which may be used in admixture with c:ellulose~ or cellulose derivatives, are above all polymeric substances havinct molecular weights between a few ten and hundred thousand gmole-'. Besides synthetic polymers, such as polyvinyl pyrrolidone and polyvinyl alcohol for example, natural and chemically 10 modified biopolymers - for' example from the group of alginates, starches and starch derivatives - arE: particularly suitable.
The detergent tablets according to the present invention preferably contain other typical detergent ingredients from the group of surfactants, builders, bleaching agents, bleach activators, enzymes, optical brighteners and other auxiliaries and additives. These substances are described in more detail in the following.
Anionic, nonionic, ~:,ationic and/or amphoteric surfactants may be used in the detergent tablets according to the invention. From the performance point of view, it is preferred to use mixtures of anionic and nonionic surfactants in which the percentage content of anionic surfactants should be greater than that of the nonionic surfactants. The total surfactant content of the tablets is (between 5 and 60% by weight, based on the weight of the tablet, surfactant contents of more than 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 C9_~3 alkyl benzene~sulfona~les, olefin sulfonates, i.e. mixtures of alkene and hydroxyalkane sulfonates, and the disulfonates obtained, for example, from C~2_~8 monoolefins with an internal or terminal double bond by sulfonation with gaseous sulfur trioxidf: 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 neutraliza-tion. The esters of a-sulfofatty acids (ester sulfonates), for example the a-sulfonated methyl esters ~of hydrogenated coconut oil, palm kernel oil 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 3 moles of fatty acid or in the transesterification of triglycerides with 0.3 to 2 molE~s of glycerol. Preferred sulfonated fatty acid glycerol esters are the sulfonation products of saturated fatty acids containing 6 to 22 carbon atoms, for ex;~mple caproic acid, caprylic acid, capric acid, myristic acid, lauric: acid, p~almitic acid, stearic acid or behenic acid.
Preferred alk(en)yl sulfates are the alkali metal salts and, in particular, the sodium salia 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_2c~ oxoalcohols and the corresponding semiesters of secondary alcc>hols 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~2_~s 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 ShE~ll 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 C9_1~ alcohols containing on average 3.5 moles of ethylene oxide (EO) or C~Z_~$ fatty alcohols containing 1 to 4 EO, are also suitable. In view of their high foaming capacity, thE~y 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 Cg_~g fatty alcohol residues or mixtures thereof. Particularly preferred sulfosuccinates contain a fatty alcohol moiety derived from ethoxylated fatty alcohols which, considered in isolation, represent nonionic surfactants (for a description, see below). Of these sulfosuccinates, those of which the fatty alcohol moieties are derived from narrow-range ethoxylated fatty alcohols are particularly preferr~sd. 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.
Other suitable anionic surfactants are, in particular, soaps. Suitable soaps are saturated fatty acid soaps, such as the salts of lauric acid, myristic acid, palrnitic aciid, stearic acid, hydrogenated erucic acid and behenic acid, and soap rnixtures 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, pota:>sium 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, palm, tallow or oleyl alcohol, and on average 2 to 8 EO per mole of alcohol are particularly preferred. Preferred ethoxylated alcohols include, for example, 02_14 alc:ohols containing 3 EO or 4 EO, C9_~~ alcohol containing 7 EO, C~3_~5 alcohols containing 3 EO, 5 EO, 7 EO or 8 EO, C~2_~$ alcohols containing 3 EO, 5 EO or 7 EO and mixtures thereof, such as mixtures of C~2_~4 alcohol coni:aining 3 EO and C,Z_,8 alcohol containing 5 EO. 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 ethoxyla~tes have a narrow homolog distribution (narrow range ethoxylates, NRE). In addition to these nonionic surfactants, fatty alcohols containing mores 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 the general formula RO(G)X where R is a primary, linear or methyl-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 also be used as further nonionic surfactants. They degree of oligomerization x, which indicates the distribution of monoglycosides and oligoglycosides, is between 1 and 10 and preferably between 1.:? and 4.
Another class of preferred nonionic surfactants which may be used either as sole nonionic surfactant or in combination with other nonionic surfactants are alkoxylatE;d, preferably ethoxylated or ethoxylated and propoxylated, fatty acid allkyl 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 581217598 or which are preferably produced by the process described in International patent application ~VIIO-A-90/13533.
Nonionic surfactants of the amine oxide type, for example N
coconutalkyl-N,N-climethyl;amine oxide and N-tallowalkyl-N,N-dihydroxy ethylamine oxide, and they 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 atom:. and 3 i:o 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 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] (II) 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 to 8 carbon atoms and R2 is a linear, branched or cyclic alkyl group or an aryl group or yin oxyalkyl group containing 1 to 8 carbon atoms, C~_4 alkyl or phenyl group; being preferred, and [ZJ is a linear polyhydroxy-alkyl group, of which the alkyl chain is substituted by at least two hydroxyl 5 groups, or alkoxyl<~ted, prE~ferably ethoxylated or propoxylated, derivatives of that group.
[Zj is preferably obtained by reductive amination of a reduced sugar, for example glucose, fructose, maltose, lactose, galactose, mannose or xylose. The N-al~;oxy- or N-aryloxy-substituted compounds may then be 10 converted into the required polyhydroxyfatty acid amides by reaction with fatty acid methyl esters iin the presence of an alkoxide as catalyst, for example in accordance with the teaching of International patent application WO-A-95107331.
As mentioned above, the nonionic surfactants are preferably not 15 distributed throughout thE; tablet, but instead are applied to a carrier material, for example the disintegrator. Although non-hydrophobicizing nonionic surfactants may also be used in other compounds or regions, it is still preferred to distribute only ionic surfactants widely over the tablet.
Builders which may be present in the detergent tablets according to the invention area in particular, silicates, aluminium silicates (more particularly zeolites), carbonates, salts of organic di- and polycarboxylic acids and mixtures of thesE~ builders.
Suitable crystalline layer-form sodium silicates correspond to the general formula Na2MSiX02X+~HZO, where M is sodium or hydrogen, x is a number of 1.9 to ~~ and y is a number of 0 to 20, preferred values for x being 2, 3 or 4. CiystallinE: layer silicates such as these are described, for example, in European patent application EP-A-0 164 514. Preferred crystalline layer silicates corresponding to the above formula are those in which M is sodium and x assumes the value 2 or 3. Both [i- and b-sodium disilicates Na2Si20~5y H20 are particularly preferred, [i-sodium disilicate being obtainable, for example, by the process described in International patent application 'WO-A- !31108171.
Other useful buildlers are amorphous sodium silicates with a modulus (Na20:SitJ2 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 silicatEa 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 they sharp ;~C-ray reflexes typical of crystalline substances in X-ray diffraction e~xperimE~nts, 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 elE~ctron 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 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 ciystallinES, synthetic zeolite containing bound water used in 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. The zeolite may be u:>ed as a spray-dried powder or even as an undried suspension still moist from its production. If the zeolite is used in the form of a suspension, i:he suspension may contain small additions of nonionic surfactants as stabilizers, for example 1 to 3% by weight, based on zeolite, of ethoxylated C~2.~8 fatty alcohols containing 2 to 5 ethylene oxide groups, C~2_~4 fatty alcohols containing 4 to 5 ethylene oxide groups or ethoxylated isotridecanols. Suitable zeolites have a mean particle size of less than 10 ~m (volume distribution, as measured by the Coulter Counter Method) and contain preferably 18 to 22% by weight and more preferably 20 to 22% by weight of bound w;~ter.
The generally knovun 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, in particular, the tripolyphosphates are particularly suitable.
Useful organic builders are, for example, the polycarboxylic acids usable, for examplle, in the form of their sodium salts, such as citric acid, adipic acid, succin~ic acid, glutaric acid, tartaric acid, sugar acids, amino carboxylic acids, nitrilotriacetic acid (NTA), providing their use is not ecologically unsafe, and mixtures thereof. Preferred salts are the salts of the polycarboxylic acids, such as citric acid, adipic acid, succinic acid, glutaric acid, tartaric acid, sugar acids and mixtures thereof.
If desired, tlhe builders mentioned may be used as carriers for the hydrophobicizing substances. However, the cellulose-based disintegrator is preferably used <~s the carrier for those substances.
Among the compounds yielding HZOZ 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 perhy-drates and H20~2-yielding peracidic salts or peracids, such as perbenzoates, peroxophth;alates, diperazelaic acid, phthaloiminoperacid or diperdodecane dioic acid.
In order to obtain an improved bleaching effect where washing is carried out at temperatures of 60°C or lower, bleach activators may be incorporated as sole component or as an ingredient of component b). The bleach activators rnay be compounds which form aliphatic peroxocarboxylic acids containing preferabh~r 1 to 10 carbon atoms and more preferably 2 to 4 carbon atoms and/or optionally substituted perbenzoic acid under perhydrolysis conditions. .Substances bearing O- and/or N-acyl groups with the number of carbon atoms mentioned and/or optionally substituted benzoyl groups are suitable. Preferred bleach activators are polyacylated alkylenediamines, more C>articularly tetraacetyl ethylenediamine (TAED), acylated triazine clerivatives, more particularly 1,5-diacetyl-2,4-dioxohexa-hydro-1,3,5-triazine (DADHT), acylated glycolurils, more particularly tetraacetyl glycoluril (TAG~U), N-acylimides, more particularly N-nonanoyl succinimide (NO~~I), acylated phenol sulfonates, more particularly n-nonanoyl or isononanoyloxybenzenesulfonate (n- or iso-NOBS), carboxylic anhydrides, more particularly phthalic anhydride, acylated polyhydric alcohols, more particularly triacetin, ethylene glycol diacetate and 2,5-diacetoxy-2,5-dihydrofuran~.
In addition to or instead of the conventional bleach activators mentioned above, so-callE~d 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, manganese-, iron-, cobalt-, rutheniurn- or molybdenum-salen complexes or carbonyl complexes. Manganese, iron, cobalt, ruthenium, molybdenum, titanium, vanadium and copper complexes with nitrogen-containing tripod ligands and cobalt-, iron-, copper- and ruthenium-ammine complexes may also be used as bleach catalysts.
In addition, the detergents according to the invention may also contain componenia with a positive effect on the removability of oil and fats from textiles by w<~shing (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 mei:hyl hydlroxypropyl 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 terephi:halic 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.
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 grisE:us, are particularly suitable. Proteases of the subtilisin type are preferrE~d, proteases obtained from Bacillus lentus being particularly preferred. Enzyme mixtures, for example of protease and amylase or proteaae 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 o:xidases have also proved to be suitable in some cases. The enzymes may be adsorbed to supports and/or encapsulated in shell-forming substances to protect them against premature decomposition.
The percentage content of the enzymes, enzyme mixtures or 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.
The tablets may contain derivatives of diamino-stilbenedisulfonic acid or alkali metal salts thereof as optical brighteners. Suitable optical brighteners are, for example, salts of 4,4'-bis-(2-anilino-4-morpholino-1,3,5 triazinyl-6-amino)-:>tilbene-2,2'-disulfonic acid or compounds of similar composition which contain a diethanolamino 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 5 alkali metal salts of 4,4'-bis-(2-sulfostyryl)-diphenyl, 4,4'-bis-(4-chloro-sulfostyryl)-diphenyl or 4G-(4-chlorostyryl)-4'-(2-sulfostyryl)-diphenyl, may also be present. IVlixtures of the brighteners mentioned above may also be used.
In preferred embodiments of the process according to the invention, 10 the particulate detergent to be compacted is compressed at temperatures below 30°C and under pressures below 15 N/cm2. The tablets according to the invention are actually produced by initially dry-mixing the constituents, which may be partly or completely pre-granulated, and subsequently shaping, more particularly tabletting, the resulting premixes 15 by conventional processes. To produce the tablets according to the invention, the premix is compacted between two punches in a die to form a solid compactate. This process, which is referred to in short hereinafter as tabletting, comprises four phases, namely metering, compacting (elastic deformation), plastiic deforrnation and ejection.

20 The premix is first introduced into the die, the filling level and hence the weight and shape of the tablet formed being determined by the position of the lower punch and the shape of the die. Uniform metering, even at high tablet throughputs, is preferably achieved by volumetric metering of the compound. As. the tabletting process continues, the top punch comes into contact with the premix and continues descending towards the bottom punch. During this compaction phase, the particles of the premix are pressed closer together, the void volume in the filling between the punches continuously diminishing. The plastic deformation phase in which the particles coalesce and fornn the tablet begins from a certain position of the top punch (and hence from a certain pressure on the premix). Depending on the physical properties of the premix, its constituent particles are also partly crushed, the premix sintering at even higher pressures. As the tabletting rate increases, i.e. at high throughputs, the elastic deformation phase becomes in~creasirngly shorter so that the tablets formed can have more or less larger voids. In the final step of the tabletting process, the tablet is forced from the die by the bottom punch and carried away by following conveyors. At this stage, only the weight of the tablet is definitively established because the tablets can still change shape and size as a result of physical processes (re-elongation, crystallographic effects, cooling, etc.).
The tabletting process is carried out in commercially available tablet presses which, in principle, may be equipped with single or double punches. In 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 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 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 gable. 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 tableaing 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 ibe raised or lowered to a particularly significant extent (filling, compaction, ejection), 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 container for the compound. The pressure applied to the compound c;an be iindividually 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 multiple-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, jacket and bull's-eye tablets - which have a structure resembling an onion skin -can also be produiced in this way. In 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 talblet 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 borE~s can be simultaneously used for tabletting.
Modern rotary tablet presses have throughputs of more than one million tablets per hour.
Suitable tabletting machines can be obtained, for example, from the following companiE~s: Apparatebau Holzwarth GbR, Asperg, Wilhelm Fette GmbH, Schwarzenbek, Hofer GmbH, Weil, KILIAN, Cologne, KOMAGE, Kell am See, KOR:SCH 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 l~4EIS, D.
The tablets, can be made in certain shapes and certain sizes.
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 than 1.
The portioned pre:;sings may be formed as separate individual elements which correspond to a predetermined dose of the detergent.
However, it is also possible to form pressings which combine several such units in a single pressing, amaller portioned units being easy to break off in particular through 'the provision of predetermined weak spots. For the use of laundry detergf:nts in machines of the standard European type with horizontally arrangied 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 are particularly suitable for the production of pressinigs such as these.
The three-dimensional form of another embodiment of the tablets according to the invention 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 dissolve on contact with water.
However, it is of course readily possible - and preferred in accordance with the present inventiion - to use the detergent tablets in conjunction with a dosing aid.
Another preferred 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 another possible embodiment, however, the various components are not compressed to form a single tablet, instead the tablets obtained comprise several layers, i.e. at least two layers. These various layers may have different dissolving rates. This can provide the tablets with favorable performance properties. If, for example, the tablets contain components which adversely affect one another, one component may be integrated in the more quickly dissolving layer while the other component may be incorporated in a more slowly dissolving layer so that the first component can already have reacted off by the time the second component dissolves.
The various layers, of the tablets can be arranged in the form of a stack, in which case the inner layers) dissolve at the edges of the tablet before the outer layers have completely dissolved. Alternatively, however, the inner layers) may also be completely surrounded by the layers lying further to the outside which prevents constituents of the inner layers) from dissolving prematurely.
In another ~preferre~d embodiment of the invention, a tablet consists of at least three layers, i.e. two outer layers and at least one inner layer, a peroxy bleaching agent being present in at least one of the inner layers whereas, in the case of tlhe stack-like tablet, the two cover layers and, in the case of the envelope:-like tablet, the outermost layers are free from peroxy bleaching agent. In another possible embodiment, peroxy bleaching agent ;end any bleach activators or bleach catalysts present and/or enzymes may be spatially separated from one another in one and the same tablet. IVlultilayE:r tablets such as these have the advantage that they can be used not only via a dispensing compartment or via a dosing unit which is added to the wash liquor, instead it is also possible in cases such as these to introduces the tablet into the machine in direct contact with the fabrics without any danger of spotting by bleaching agent or the like.
Similar effects can also be obtained by coating individual constituents of the detergent composition to be compressed or the tablet as 5 a whole. To this end, i:he tablets to be coated may be sprayed, for example, with aqueous solutions or emulsions or a coating may be obtained by the process known as melt coating.
After pressing, the detergent tablets have high stability. The fracture resistance of cylindrical tablets can be determined via the diametral fracture 10 stress. This in turn can Ibe determined in accordance with the following equation:

a=
~Dt where a represent, the diametral fracture stress (DFS) in Pa, P is the force in the N which leads to the pressure applied to the tablet that results in fracture thereof, D is the dliameter of the tablet in meters and t is its height.
Examples Three detergent tablet variants 1, 2 and 3 with the same composition shown in Table 'I were produced by tabletting a particulate detergent composition. Examples 1 and 2 correspond to the invention while Example 3 is a Comparison Example.

Table 1:
Composition of the detergent tablets [% by weight]
Surfactant granules 61.4 C~2_~$ fatty alcohol sulfate 4.0 Sodium perborate 16.0 Tetraacetyl ethylenediamine (TAED) 7.3 Cellulose 4.0 Terephthalic acid/E~thylene glycol/PEG0.75 ester (soil release polymer) Foam inhibitor 3.5 Enzymes 2.3 Brightener 0.15 Perfume ~ 0.45 Salts/water Balance Table 2:
Composition of the surfactant granules [% by weight]
C9_~3 alkyl benzenEaulfonate 20.0 C~2_~8 fatty alcohol + 7 EO 5.8 Soap 1.7 Zeolite 33.0 Sodium carbonate 17.8 Sodium silicate 5.0 Acrylic acid/maleic acid copolymer 6.6 Optical brightener 0.26 Salts/water ~ Balance In tablets 11 according to the invention, the perfume was added separately from the other' ingredients in the form of a perfume/cellulose compound. In tablets 2 according to the invention, the perfume was applied to the surfactant .compound separately from the other ingredients and, after mixing with the remaining ingredients, the mixture was compressed to tablets. In the comparison tablets 3, the perfume was uni-formly distributed throughout the tablet by spraying the mixture to be tabletted with perfume.
The hardness of the tablets was measured by deforming the tablets until they broke, the force being applied to the sides of the tablet and the maximum force withstood by the tablets being determined.
To determine tablet disintegration, tablets were placed in a glass beaker filled with water (600 ml water, temperature 30°C) and the time taken for the tablets to disintegrate completely without mechanical assistance was measured.
For the "dispensing" test, three 40 g tablets were placed in the dispensing compartment of the washing machine used. After the dispens-ing phase, the residue in the compartment was dried and weighed out.
The test results area shown in Table 3 below:
Table 3:
Detergent tablets [physicail properties]
Tablet Example Example 2 Example Tablet hardness 15 N 15 N 15 N

Tablet disintegration 20 secs. 20 secs. >50 secs.

Residue - - 9 9

Claims (8)

1. A detergent tablet of compacted particulate detergent containing surfactant(s), builders, a cellulose-based disintegration aid and optionally other detergent ingredients, characterized in that all the hydrophobicizing substances are applied to a carrier material.

2. A detergent tablet as claimed in claim 1, characterized in that a surfactant compound is used as the carrier material.

3. A detergent tablet as claimed in claim 1 or 2, characterized in that the cellulose-based disintegrator is used as the carrier material.

4. A detergent tablet as claimed in any of claims 1 to 3, characterized in that it contains nonionic surfactants applied to a carrier material as hydrophobicizing substances.

5. A detergent tablet as claimed in any of claims 1 to 4, characterized in that it contains foam inhibitor applied to a carrier material as a hydrophobicizing substance.

6. A detergent tablet as claimed in any of claims 1 to 5, characterized in that it contains perfume applied to a carrier material as a hydrophobicizing substance.

7. A detergent tablet as claimed in any of claims 1 to 6, characterized in that the hydrophobicizing substance applied to a carrier material is in the form of a separate layer, a coating or individual inserts.

8. A detergent tablet as claimed in any of claims 1 to 7, characterized in that the hydrophobicizing substance applied to a carrier material is granulated with other detergent ingredients to form a compound before the tabletting process.