CA2300630A1 - Washing and cleaning agent shaped bodies with improved solubility - Google Patents

Abstract

The invention relates to washing an cleaning agents in the form of shaped bodies, consisting of compressed, particulate washing and cleaning agents containing a tenside (s), builders, a cellulose-based disintegration agent and optionally, other washing and cleaning agent constituents. The disintegration agent is in a blocked-off area of the shaped body so that it is spanally separate from the hydrophobing substances. By separating the disintegration agent from substances which could prevent moisture from reaching the same, the invention ensures that the shaped bodies display excellent dissolving properties.

Description

Washing and Cleaning Agent Shaped Bodies with Improved Solubility This invention relates generally to compact shaped bodies (tablets) having detersive propertiE~s. 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. A:. 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 pressures, the ingredients of the tablet are heavily compacted so that disintegration of the tablet in the wash liquor is delayed which results in excessively 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 disinvtegration aids, so-called tablet disintegrators, have been used for some times in order to shorten the disintegration times. According to Rompp (9th Edition, \/ol. 6, page 4440) and Voigt "Lehrbuch der pharmazeutischen Techr~ologie" (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 Handbuclh der pharmazeutischen Praxis" (5th Edition, 1991, page 942) classifies the disintegration accelerators or disintegrators according to their action mechanism, 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 vuater (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 andl 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 witlh water. In the case of the wicking mechanism, water is drawn into the intf~rior of the tablet by the disintegration accelerator and loosens the binding forces 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 effiect of the electrical forces generated. A totally different mechanism forms the basis of "effervescent tablets" which contain active substances or active-substance systems which, on contact with water, release gases that cause the tablet to burst. In addition, it is known to use hydrophilicizing ac,~ents which provide for better wetting of the compressed particles in water and hence for faster disintegration.
Whereas substancEa which act by the last two of the above-mentioned mechanisms can easily be distinguished from other disintegration mechanisms, the effects on which the swelling and deformation mechanisms <~nd the wicking and repulsion mechanisms are based cannot always be clearly distinguished from one another, so that classification into hydrophilicizing 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 generally 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 disintec~rator during 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 tableited 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 1464 (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 binders 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 connposition 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;abletting 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.
None of the documents cited above is concerned with improving the solubility of detergent tabNets by selective modification or incorporation of 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 a cellulose-based disintegrator.
The present invention relates to a detergent tablet of compacted particulate detergE;nt containing surfactant(s), builders, a cellulose-based disintegration aid (disintegrator) and optionally other detergent ingredients, the disintegrator in the tablet being present spatially separated from hydro-phobicizing substances in a demarcated region of the tablet.
The detergent tablE~ts according to the present invention solve the problem of inadE~quate tablet disintegration through an inadequate disintegrating effect of thE: cellulose-based disintegrator by separation of hydrophobicizing constituents, which can reduce the disintegrating effect, from the disintegrator.
In the tablets according to the invention, at least one spatially demarcated region contains the cellulose-based disintegrator and optionally other components which do not adversely affect the disintegrating effect. These non-hydrophobicizing substances emanate, for example, from the group of builders, ionic surfactants, bleaching agents and bleach activators and other optional detergent ingredients.
The spatial demarcation of the disintegrator can be achieved in various ways. Thus, the demarcated region may assume the form of a separate layer, a ~:,oating or individual inserts while the hydrophobicizing substances may be present in other layers, in other coating or the core or even in the main matrix ~of the tablet. Another possibility is to produce comparatively large granules or extrudates which are protected by the coating and are di:>tributedl through the tablet.
In one preferred Embodiment of the invention, the demarcated region containing the disintegrator does not contain the disintegrator on its own, but rather in admixture with other non-hydrophobicizing substances.
Preferred detergent tablE~ts contain the disintegrator and other non-hydrophobicizing detergent ingredients in the demarcated region.
In another preferred embodiment of the invention, the demarcated region contains the disintE:grator and at least part of the total quantity of builders and ionic surfactants present in the tablet. Particularly preferred detergent tablets have a demarcated region which contains bleaching agent and/or bleach activator in addition to the disintegrator.
Without wanting to be limited in any way by this theory, applicants assume that the separation of the hydrophobicizing components from the disintegrator makes it easier for water to reach the disintegrator, thereby accelerating tablet disintegration.
Preferred tablets are 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 particles which in turn are compressed to tablets. The secondary particles which contain the disintegrator are separated from hydrophobicizing substances and, in this way, can be quickly wetted and moistened by water and develop their full effect.
Hydrophobicizing substances in the context of the present invention are understood to be suibstances which reduce the wettability of the disintegrator or thc: secondary particles containing the disintegrator with water. In particular, typically hydrophobic substances, such as paraffins and silicones (used as defoamers in detergents) or perfume oils, are not present in the demarcated region. Other hydrophobicizing substances are, for example, nonionic suri~actants 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-hydrophobiciziing nonionic surfactants is difficult. The expert will have no difficulty in findiing nonionic surfactants with an overly hydrophobicizing character and keeping them away from the demarcated region. 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 surfactants, the dmarcated region containing the disintegrator is preferably free from nonionic surfactants. Preferred tablets contain nonionic surfactants spatially separated from the demarcated region as hydrophobicizing substances.
Suitable foam inhilbitors 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 mixturEa 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. The foann inhibitors are preferably applied to a granular water-soluble or water-dispersible carrier material. Mixtures 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 not present in the demarcated region containing the disintegrator.
Preferred detergent tablets contain foam inhibitors spatially separated from the demarcated region as a hydrophobicizing substance.
Dyes and fragrances are added to the detergent tablets according to the invention to improve tlhe 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 tlhe estE~r type are, for example, benzyl acetate, phenoxyethyl isobutyrate, p-tert.butyl cyclohexyl acetate, linalyl acetate, dimethyl benzyl aarbinyl .acetate, phenyl ethyl acetate, linalyl benzoate, benzyl formate, etlhyl 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, citronellyloxy-acetaldehyde, cyclamen aldehyde, hydroxycitronellal, lilial and bourgeonal;
the ketones include, for Example, the ionones, a-isomethyl ionone and methyl cedryl ketone; they 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, junipE~r berry oil, vetiver oil, olibanum oil, galbanum oil and labdanum oil and oranges blossom oil, neroli oil, orange peel oil and sandalwood oil.
The detergent tablE~ts 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 also be used together with the disintegrator in the demarcated region. According to the invention, the pE~rfumes which have a pronounced hydrophobicizing character should be present spatially separated from the disintegrator.
Preferred detergent tablets contain perfume spatially separated from the demarcated region as a hydrophobicizing substance.
Spatial separation in the context of the present invention means that the separate layer, coating or individual insert containing the disintegrator is completely free from the hydrophobicizing substances mentioned. As mentioned above, this c;an be achieved, for example, by producing separate secondary granules which - apart from the disintegrator - contain only non-hydropho~bicizing substances and tabletting them after mixing with other ingredients .and/or compounds. A two-layer or multilayer tablet in which only one layer contains disintegrator could also be produced. In that case, hydrophobicizing substances may be used in (one of) the other layer/layers.
In the context of they 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 ~3-1,4-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 sizes of the cellulose are preferably below 100 Nm, more preferably below 70 pm aind 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 modifiE~d celluloses include, for example, products of esterification or ei:herification reactions in which hydroxy hydrogen atoms have been substituted. ~lowever, 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 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 form of a mixture with cellulose as cellulose-based disintegrators. The contE;nt 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 embodirnent, pure cellulose free from cellulose derivatives is used as the cellulose-based disintegrator.
Microcrystalline celllulose 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 maws) 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 particle 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.
Suitable swellable water-insoluble disintegration aids, which may be used in admixture with c;ellulose~ or cellulose derivatives, are above all polymeric substances having molecular weights between a few ten and hundred 5 thousand gmole'. Be:>ides synthetic polymers, such as polyvinyl pyrrolidone and polyvinyl alcohol for example, natural and chemically modified biopolym~ers - for example from the group of alginates, starches and starch derivatives - arE~ particularly suitable.
The detergent tablets according to the present invention preferably 10 contain other typical detergent ingredients from the group of surfactants, builders, bleachingi agents, bleach activators, enzymes, optical brighteners and other auxiliaries and additives. These substances are described in more detail in the following.
Anionic, noinionic, cationic 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 surfactania 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~tes, olefin sulfonates, i.e. mixtures of alkene and hydroxyalkane sulfionates, 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 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 ghycerol. 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, p:almitic acid, stearic acid or behenic acid.
Preferred a~lk(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_2,~ oxoalcohols and the corresponding semiesters of secondary alcohols with the same chain length. Other preferred alk(en)yl sulfates acre those with the chain length mentioned which contain a synthetic, linear alkyl clhain based on a petrochemical and which are similar in their degradation behavior to the corresponding compounds based on oleochemical raw materials. C~2_~6 alkyl sulfates, C~2_~5 alkyl sulfates and C~4_~~, alkyl sulfates are preferred from the point of view of washing technology. Other suitable anionic surfactants are 2,3-alkyl sulfates which ma,y be produced, for example, in accordance with US
3,234,258 or US 5,075,0.41 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 i:o 6 moles of ethylene oxide, such as 2-methyl-branched Cg_~~ alcohols containing on average 3.5 moles of ethylene oxide (EO) or C~2_~$ fatty alcohols: containing 1 to 4 EO, are also suitable. In view of their high foaming capacity, they are only used in relatively small quantities, for example in quantitiies 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 alcoholls, preferably fatty alcohols and, more particularly, ethoxylated fatty alcohols. Preferred sulfosuccinates contain Ca_~$ 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 frorn narrow-range ethoxylated fatty alcohols are particularly preferrE:d. 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, palmitic acid, stearic acid, hydrogenated erucic acid and behenic acid, and soap nnixtures 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 sodiurn, 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 fapecially 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 l:he 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, C12-14 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_~8 alcohols containing 3 EO, ;i 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. 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 amd G stands for a glycose unit containing 5 or 6 carbon atoms, preferably gluco:>e, may also be used as further nonionic surfactants. They degree of oligomerization x, which indicates the distribution of mor~oglycos,ides and oligoglycosides, is between 1 and 10 and preferably betVVeen 1.:? and 4.
Another cla;>s 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 <:hain, 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 1N0-A-90113533.

Nonionic surfactants of the amine oxide type, for example N-coconutalkyl-N,N-dimethylamine oxide and N-tallowalkyl-N,N-dihydroxy-ethylamine 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 ins 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-C O-N-[Z] ( I ) in which RCO is an aliphatic acyl group containing 6 to 22 carbon atoms, R' is hydrogen, ain 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 acicl chloride.
The group of polyhydroxyfatty acid amides also includes compounds corresponding to formula (I'I):
R'-O-RZ
R-C O-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 to 8 carbon atoms and RZ 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 polyhydroxy-alkyl group, of which the alkyl chain is substituted by at least two hydroxyl groups, or alkoxylated, preferably ethoxylated or propoxylated, derivatives of that group.
[Z] is preferably obtained by reductive amination of a reduced sugar, for example glucose, frucaose, maltose, lactose, galactose, mannose or xylose. The N-al~;oxy- 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 wii:h the teaching of International patent application WO-A-95/07331.
As mentioned above, the nonionic surfactants are preferably not used in the demarcated region containing the disintegrator. Although non-hydrophobicizing nonionic surfactants may be used together with the disintegrator, it is swill prefE~rred to use only ionic surfactants in the spatially demarcated region.
Builders whiich may be present in the detergent tablets according to the invention area in particular, silicates, aluminium silicates (more particularly zeolite:;), 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+~A 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. 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 [3- and 8-sodium disilicates Na2Si205A y H20 are particularly preferred, [i-sodium disilicate being obtainable, for exarnple, by the process described in International patent application WO-A- q1108171.
Other useful builders are amorphous sodium silicates with a modulus (Na20:Sin2 ratioy 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 dlelay 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 ;K-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 whiich have a width of several degrees of the diffraction angle. ~Howeve~r, 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 crystalline, 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, the suspension may contain small additions of nonionic surfactants as stabilizers, for example 1 to 3% by weight, based on zeolite, of ethoxylated C12_~8 fatty alcohols containing 2 to 5 ethylene oxide groups, C~2_~4 fatty alcohola 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 2:?% by weight and more preferably 20 to 22% by weight of bound w<~ter.
The generally kno~nrn 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 example, in thE: form of their sodium salts, such as citric acid, adipic acid, succinic 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.
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 perc,arbonate, peroxypyrophosphates, citrate perhy-drates and H202-yielding peracidic salts or peracids, such as perbenzoates, peroxophth<~lates, diperazelaic acid, phthaloiminoperacid or diperdodecane dioic acid.
In order to .obtain an improved bleaching effect where washing is carried out at temperaturEa of 60°C or lower, bleach activators may be incorporated as sole component or as an ingredient of component b). The bleach activators may be compounds which form aliphatic peroxocarboxylic acids containing preferably 1 to 10 carbon atoms and more preferably 2 to 4 carbon atoms and/or optionally substituted perbenzoic acid under perhydrolysis conditions. ~~ubstances bearing O- and/or N-acyl groups with the number of carbon <~toms mentioned and/or optionally substituted benzoyl groups are suitable. Preferred bleach activators are polyacylated alkylenediamines, more particularly tetraacetyl ethylenediamine (TAED), acylated triazine derivatives, more particularly 1,5-diacetyl-2,4-dioxohexa-hydro-1,3,5-triazirne (DADHT), acylated glycolurils, more particularly tetraacetyl glycoluril (TAC~U), N-acylimides, more particularly N-nonanoyl succinimide (NO:iI), acylated phenol sulfonates, more particularly n-nonanoyl or isononanoylo:Kybenzenesulfonate (n- or iso-NOBS), carboxylic anhydrides, more particularly phthalic anhydride, acylated polyhydric alcohols, more particularlly triacetin, ethylene glycol diacetate and 2,5-diacetoxy-2,5-dihy~drofurari.
In addition to or instead of the conventional bleach activators mentioned above, 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, manganese-, iron-, cobalt-, ruthenium- or molybdenum-salen complexes or carbonyl complexes. Manganese, iron, cobalt, ruthenium, molybdenum, titanium, vanadium and copper coimplexes 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 components with a positive effect on the removability 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 acrid known from the prior art or derivatives thereof, more particularly polymer:; 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, cellulas~es or mixtures thereof. Enzymes obtained from bacterial strains or fungi, such ass Bacillus subtilis, Bacillus licheniformis and Streptomyces griseus, are particularly suitable. Proteases of the subtilisin type are preferrf~d, 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. Peroxida:;es or oxidases have also proved to be suitable in some cases. The enzymes may be adsorbed to supports and/or encapsulated in shell-forming subsi:ances 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% Iby 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 com-position 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 alkali metal salts of 4,4'-bis-(2-sulfostyryl)-diphenyl, 4,4'-bis-(4-chloro-3-sulfostyryl)-diphenyl or 4~-(4-chlorostyryl)-4'-(2-sulfostyryl)-diphenyl, may also be present. h~ixtures of the brighteners mentioned above may also be used.
In preferred embodiments of the process according to the invention, the particulate detergent to be compacted is compressed at temperatures 5 below 30°C and under pressures below 15 N/cmz. 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 by conventional processE;s. To produce the tablets according to the 10 invention, the premix is coimpacted 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), plastic deformation and ejection.
The premix is first introduced into the die, the filling level and hence 15 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, i~; 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 20 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 forrn 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 increasingly shorter so that the tablets formed can have more or less large 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 volumea, 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 talblets 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-callE~d die table. The number of dies varies - according to model - between 6 and 55, although even larger dies are commercially available. Top and bottonn punches are associated with each die on the die table, the tabletting prE~ssures 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 nnove 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 k>e 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 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 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 produced 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 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 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 LAEIS, 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, cylinclrical 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 pressings may be formed as separate individual elements which correspond to a predetermined dose of the detergent.
However, it is also possiblle to form pressings which combine several such units in a single pressing, smaller portioned units being easy to break off in particular through the 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 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 intn~duced 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 invention - 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 :.pots, 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 compressE~d 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 hates. 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 i:ablets 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 preferred 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 the 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 and any bleach activators or bleach catalysts present and/or enzymes may be ~;patially separated from one another in one and the same tablet. ~Aultilaye~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 introduce the tablet into the machine in direct contact with the fabrics without any danger of spotting by bleaching agent or the like.
Similar effE~cts can also be obtained by coating individual constituents of the detergent composition to be compressed or the tablet as a whole. To this end, the 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 stress. This in turn can Ibe determined in accordance with the following equation:

BDt where ~ represents 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 diameter 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 1 were produced by tabletting a particulate detergent composition obtained by mixing basic granules with powder-form aftertreatment component:>. Example 1 corresponds to the invention while Examples 2 and are Comparison Examples.
Table 1:
Composition of the detergE:nt tablets [% by weight]
Basic granules 62.75 Zeolite 1.0 Sodium perborate monohydrate 17.4 TAED 7.3 Foam inhibitor 33.5 Enzymes 2.5 Disintegration aid 4.0 Table 2:
Composition of the basic granules [% by weight]
Cg_~3 Alkyl benzenesulfonate 18.9 C~2_~$ Fatty alcohol + 7 EO 5.2 C~2_~g Fatty alcohol sulfate 4.1 Soap 2.5 Optical brightener 0.2 Sodium carbonate 17.9 Sodium silicate 5.0 Acrylic acid/maleic acid copolymer6.0 Zeolite A (water-free actives 28.5 substance) Water 8.9 Salts ~ Balance In tablets 1 according to the invention, the perfume was added to the basic granules separately from the cellulose before mixing with the powder-form aftertreatmeni: components In comparison tablets 2, the perfume was sprayed onto the tabletting mixture of basic granules and powder-form aftertreatment components, the disintegration aid only being added after spraying of the mixture with perfume. Comparison Example 3 is a tablet in which the nonionic surfactants were not introduced via the basic granules but were added to a mixture of anionic: surfactant granules and powder-form aftertreatment components. The perfume was sprayed last onto the mixture 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 wii:hstood 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 mE:asured, For the "diapensirng" 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 are shown in Table 3 below:
Table 3:
Detergent tablets [physical properties]
Tablet Example 1 Example 2 Example Tablet hardness 35 N 25 N 20 N

Tablet disintegration 17 secs. 30 secs. >60 secs.

Residue 4 g 4 g 34 g

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 the disintegration aid in the tablet is present spatially separated from hydrophobicizing substances and any nonionic surfactants present in a demarcated region of the table, with the proviso that. where microcrystalline cellulose is used as the cellulose-based disitegration aid, it is present in the form of compacted granules with a mean particle size of 200 µm.

2. A detergent tablet as claimed in claim 1, characterized in that the demarcated region contains the disintegration aid and other non-hydrophobicizing detergent ingredients.

3. A detergent tablet as claimed in claim 1 or 2, characterized in that the demarcated region contains the disintegrator and at least part of the total quantity of builders and ionic surfactants present in the tablet.

4. A detergent tablet as claimed in any of claims 1 to 3, characterized in that the demarcated region contains bleaching agent and/or bleach activator in addition to the disintegration aid.

5. A detergent tablet ass claimed in any of claims 1 to 4, characterized in that it contains nonionic surfactants spatially separated from the demarcated region as hydrophobicizing substances.

6. A detergent tablet ass claimed in any of claims 1 to 5, characterized in that it contains foam inhibitor spatially separated from the demarcated region as a hydrophobicizing substance.

7. A detergent tablet ass claimed in any of claims 1 to 6, characterized in that it contains perfume spatially separated from the demarcated region as a hydrophobicizing substance.

8. A detergent tablet as claimed in any of claims 1 to 7, characterized in that the demarcated region is in the form of a separate layer, a coating or individual inserts.