CA2297443A1 - Multiphase detergent tablets - Google Patents

Abstract

Two-phase or multiphase detergent tablets of compacted particulate detergent comprising surfactant(s), builder(s) and optionally other detergent ingredients, in which the surfactant content of the individual phases of the tablets vary by more than 3% by weight, based on the weight of the individual phase, a cellulose-containing disintegration aid containing at most 10% by weight of particles under 200 µm in size being present in larger quantities in the phase(s) with the higher surfactant content than in the phase(s) with the lower surfactant content, have improved disintegration properties despite high hardness values.

Description

MULTIPHASE DETERGENT TABLETS
Field of the Invention This invention relates generally to multiphase detergent tablets.
More particularly, the invention relates to multiphase detergent tablets for washing laundry in a domestic washing machine.
By virtue of the ease with which they can be dosed and other advantages in regard to packaging, transportation and storage, tablets afford a number of advantages which make it appear desirable also to produce detergents in tablet form. A broad prior art exists on the subject of detergent tablets, being concerned in particular with overcoming a major problem of tablets, namely the dichotomy between the hardness of tablets on the one hand and their disintegration rate on the other hand. Adequate hardness is essential for the packaging, storage, transportation and handling of tablets while their disintegration properties critically influence the washing process and sufficiently rapid disintegration is absolutely essential for the formation of a suitably concentrated wash liquor.
Background of the Invention The problem of finding a technically reasonable compromise between hardness and disintegration is further complicated in the case of multiphase tablets. It can be of advantage with the washing process in mind to separate certain detergent ingredients from one another.
However, such separation does lead to differences in the physical property profiles of the various phases in the tablet. Thus, in the extreme case, inter-phase adhesion can diminish to such an extent that multiphase tablets can no longer be produced. The effect of an excessive difference in hardness between different phases would be that certain phases would be damaged to a greater extent during packaging, transportation and handling than other phases. In addition, excessive differences between the disintegration and dissolving rates of individual phases would also be undesirable because otherwise active ingredients from the more slowly disintegrating or dissolving phase would not be available to the washing process. Moreover, it may be desirable for the individual phases of the tablets to have different surfactant contents in order to increase the freedom of choice in selecting particular formulations.
Accordingly, it is crucially important in the case of multiphase detergent tablets for all the phases to adhere to one another and to show adequate and comparable hardness and a sufficiently rapid and identical disintegration and dissolving profile, even when the individual phases differ significantly in their surfactant content. Proposed solutions to these problems are described in only a few prior-art publications.
Multiphase detergent tablets where the surfactant content of the individual phases of the tablets varies by no more than 3% by weight, based on the weight of the individual phase, are described in earlier German patent application DE 198 03 409.1 (Henkel KGaA). Differences in hardness, solubility and disintegration times between the individual phases are avoided in this way.
Multiphase detergent tablets where the surfactant content of the individual phases of the tablets varies by more than 3% by weight, based on the weight of the individual phases, are the subject of earlier German patent application DE 198 03 410.5 (Henkel KGaA). This application teaches that differences in hardness, solubility and disintegration times between the individual phases can be avoided, even where the individual phases differ fairly significantly in their surfactant content, if the phases) with the higher surfactant content contains) a component with an oil absorption capacity of at least 20 g/100 g in larger quantities than the phases) with the lower surfactant content. Besides fine-particle cellulose fibers, this document mentions silicas and/or zeolites in particular as components with a high oil absorption capacity. The detergent tablets described in the Examples contain cellulose - in equal amounts in the two phases - as a disintegration aid. There are no particulars of the particle size of the cellulose used in the document in question.
Now, the problem addressed by the present invention was to provide multiphase detergent tablets which would overcome the disadvantages mentioned above. More particularly, the invention sought to provide multiphase detergent tablets which would have high hardness values and high disintegration and dissolving rates in all phases, irrespective of the degree of difference in surfactant content between the individual phases.
Brief Description of the Invention It has now been found that multiphase detergent tablets with an excellent property profile can be produced provided that - where the surfactant contents in the individual phases vary - one or more cellulose-containing disintegrators is/are added to the phases) with the higher surfactant content in larger quantities than to the phases) with the lower surfactant content during the aftertreatment of the premix to be tabletted.
Accordingly, the present invention relates to two-phase or multiphase detergent tablets of compacted particulate detergent comprising surfactant(s), builders) and optionally other detergent ingredients, characterized in that the surfactant content of the individual phases of the tablets varies by more than 3% by weight, based on the weight of the individual phase, a cellulose-containing disintegration aid containing at most 10% by weight of particles under 200 Nm in size being present in larger quantities in the phases) with the higher surfactant content than in the phases) with the lower surfactant content.
Detailed Description of the Invention More particularly, the present invention provides adetergent tablet having at least two phases comprising compacted detergent granules comprising surfactant(s), builders) and optionally other detergent ingredients, wherein the surfactant content of the individual phases of the tablet varies by more than 3% by weight, based on the weight of the individual phase, a cellulose-containing disintegration aid containing at most 10% by weight of particles under 200 p,m in size being present in larger quantities in the phases) with the higher surfactant content than in the phases) with the lower surfactant content.
In the context of the present invention, the variation of the surfactant content by more than 3% by weight, based on the weight of the individual phases, means that the absolute values of the surfactant content in the phases vary by more than 3% by weight. If, therefore, one phase contains 20% by weight of surfactant(s), the surfactant content of the other phases) must be selected so that the range of variation about the value 20 is more than 3% by weight. In other words, the percentage figure for the surfactant content of the phase with the lower surfactant content is subtracted from that of the phase with the higher surfactant content, the result from phase to phase having to be > 3. In a four-phase tablet, this would mean that - for a surfactant content of 12% by weight in the phase with the lowest surfactant content - the next phases would have surfactant contents of, for example, 15.1 % by weight, 18.2% by weight and 21.3% by weight, the "> 3% by weight" condition being fulfilled in each case by a difference of 3.1 % by weight.
With increasing surfactant content, the individual phases of the detergent tablets according to the invention contain increasing amounts of a cellulose-containing disintegration aid which contains at most 10% by weight of particles below 200 Nm in size, with the proviso that the phase with the higher surfactant content contains a larger amount of this disintegration aid, based on the overall composition of the phase. In a preferred embodiment of the invention, the content of cellulose-containing disintegration aid in the phases) richer in surfactant is higher by at least 2.5% by weight, preferably by at least 5% by weight and more preferably by at least 10% by weight, based on the weight of the disintegration aid, than in the phases) with the lower surfactant content. On the basis of the above-mentioned example of a four-phase tablet, the facts may be illustrated as follows: if, besides the 12% by weight of surfactant mentioned, the phase with the lowest surfactant content contains 1.5% by weight of the cellulose-containing disintegration aid, the second phase would contain at least 1.5375% by weight (preferably 1.575% by weight and more preferably 1.65% by weight) of that component. The content of cellulose-containing disintegration aid in the third phase is determined by the real content of that component in the second phase - here, too, the difference is preferably at least 0.3% by weight, more preferably at least 0.5% by weight and most preferably at least 1.0% by weight. The same applies to the fourth phase.
By using the cellulose-containing disintegration aid in different 5 quantities in the individual layers, the disintegration times of the layers can be made very similar to one another, thus avoiding the problems mentioned above. According to the invention, detergent tablets where the disintegration times of the layers differ from one another by at most 5 seconds are preferred.
According to the invention, a cellulose-containing disintegration aid of cellulose fibers with a primary fiber length of under 100 Nm, which have been compacted to a particle spectrum of 200 to 2,000 Nm, may be used as the cellulose-based disintegration aid. Further particulars of the cellulose-containing disintegration aid can be found in the following.
Besides the absolute content of surfactants) and the cellulose-containing disintegration aid in the individual phases, based on the composition of the individual phase, the ratio of the quantities in the individual phases to one another is also variable. According to the invention, preferred detergent tablets are those in which the quantity ratio of the cellulose-containing disintegration aid between the individual phases is greater than the quantity ratio of the surfactants between those phases.
If the above-mentioned example is again used for illustration, the ratio of the surfactant contents between phase 2 and phase 1 is 15.1:12.0 - 1.26:1. Now, the second phase compared with the first preferably contains so much cellulose-containing disintegration aid that the ratio of this component in the two phases is greater than 1.26. If, therefore, phase 1 contains, for example, 1.5% by weight of the cellulose-containing disintegration aid, phase 2 should contain more than 1.26 times that quantity, i.e. at least 1.9% by weight of the component in question. Now, depending on how large the content of surfactant and disintegration aid in the individual phase is, the contents of these ingredients in the other phases can be varied so that they satisfy the criteria mentioned. In the case of a phase which is free from cellulose-containing disintegration aid, the formation of ratios is mathematically pointless so that absolute values in the sense of the preferred embodiments of the invention described in the foregoing are used in such a case.
The cellulose-containing disintegration aid containing at most 10%
by weight of particles under 200 Nm in size present in the individual surfactant-containing phases of the tablet may be pure cellulose in the particle size range mentioned although co-granules of cellulose and/or cellulose derivatives with other substances, especially detergent ingredients, may also be used. Corresponding granules containing other ingredients besides cellulose are described, for example, in German patent applications DE 197 23 028.8, DE 198 53 173.7 and DE 199 01 063.3 (all Henkel KGaA) and are preferably used for the purposes of the present invention.
The cellulose present in the cellulose-containing disintegration aid has the formal empirical composition (C6H~pO5)n and, formally, is a ~i-1,4-polyacetal of cellobiose which, in turn, is made up of two molecules of glucose. Suitable celluloses consist of ca. 500 to 5000 glucose units and, accordingly, have average molecular weights of 50,000 to 500,000.
According to the invention, cellulose derivatives obtainable from cellulose by polymer-analog reactions may also be used as cellulose-containing disintegrators. These chemically modified celluloses include, for example, products of esterification or etherification reactions in which hydroxy hydrogen atoms have been substituted. However, celluloses in which the hydroxy groups have been replaced by functional groups that are not attached by an oxygen atom may also be used as cellulose derivatives.
The group of cellulose derivatives includes, for example, alkali metal celluloses, carboxymethyl cellulose (CMC), cellulose esters and ethers and aminocelluloses. The cellulose derivatives mentioned are preferably not used on their own, but rather in the form of a mixture with cellulose as cellulose-based disintegrators. The content of cellulose derivatives in mixtures such as these is preferably below 50% by weight and more preferably below 20% by weight, based on the cellulose-containing disintegrator.
According to the invention, the cellulose-containing disintegration aid must contain less than 10% by weight of particles under 200 Nm in size. It is preferably converted into a coarser form, for example by granulation or compacting, before it is added to and mixed with the premixes to be tabletted. Detergent tablets which contain granular or optionally co-granulated disintegrators are described in German patent applications DE 197 09 991 (Stefan Herzog) and DE 197 10 254 (Henkel) and in International patent application WO 98/40463 (Henkel). Further particulars of the production of granulated, compacted or co-granulated cellulose disintegrators can also be found in these patent applications.
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 the 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 microfine 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 larger particle size.
As already mentioned, the cellulose-containing disintegration aid is preferably used in a relatively coarse-particle, granulated or compacted form. Preferred detergent tablets are characterized in that the cellulose-containing disintegration aid present in them contains less than 20% by weight, preferably less than 10% by weight and more preferably less than 5% by weight of particles under 400 Nm in size. The maximum particle size of the disintegration aid is also preferably limited. According to the invention, preferred detergent tablets are those in which the cellulose-containing disintegration aid present in them contains less than 20% by weight, preferably less than 10% by weight and more preferably less than ' CA 02297443 2000-O1-28 5% by weight of particles over 1200 Nm in size.
As described above, suitable cellulose-containing disintegration aids besides pure cellulose are co-granulates or co-compactates of cellulose with other substances. Preferably, the cellulose-containing disintegration aids used consist predominantly of cellulose, i.e. preferred detergent tablets are characterized in that at least 60% by weight, preferably at least 75% by weight and more preferably at least 90% by weight of the cellulose-containing disintegration aids present in them consist of cellulose.
According to the invention, the individual phases of the tablets may assume various three-dimensional forms. The most simple embodiment is a two-layer or multilayer tablet, each layer of the tablet representing one phase. However, it is also possible in accordance with the invention to produce multiphase tablets in which individual phases assume the form of inclusions in (an)other phase(s). Besides so-called "ring/core" tablets, jacket tablets or combinatiori's of the embodiments mentioned are also possible. Examples of multiphase tablets can be found in the drawings of EP-A-0 055 100 (Jevesl which describes toilet cleaninn hlnnkc Technically the most common form of multiphase tablets are two-layer or multilayer tablets. According to the invention, therefore, the phases of the tablet are preferably in the form of layers.
According to the invention, it is crucial that the surfactant content of the individual phases of the tablet vary by more than 3% by weight, based on the weight of the individual phase, and that the phases) with the higher surfactant content contain more cellulose-containing disintegration aid than the phases with the lower surfactant content. Determination of the surfactant content is based on the sum of the surfactants present in the particular phase, irrespective of the type of surfactant involved. If one phase contains anionic and nonionic surfactants, for example, the total surfactant content of the phase is the sum of the quantities of anionic and nonionic surfactants.
The surfactants may be incorporated in the individual phases of the tablet in pure form. This is readily possible, for example, in the case of soaps or other readily processable surfactants. With many surfactants, however, it is advisable to incorporate surfactant compounds rather than the pure surfactants. These compounds - which should have high surfactant contents according to the particular application - may be produced by conventional processes, such as spray drying, granulation or compounding. A combination of several batches of surfactant granules or a combination of surfactant granules with pure surfactants is of course also possible.
According to the invention, the surfactants) are introduced into the phases of the tablets through surfactant-containing granules.
In other embodiments of the present invention, different surfactant granules may be used for each phase. However, each phase may also derive its surfactant content from the same granules which are therefore present in all phases of the tablet. Another preferred embodiment of the invention is characterized in that the same surfactant granules are used in all phases of the tablets, detergent tablets comprising two layers which contain the same surfactant granules in different quantities being p refe rred .
Now, the most simple possible embodiment of the present invention is a two-phase tablet in which the phases are present as layers and in which the same surfactant granules are used in different quantities in the two layers. These tablets of two layers containing the same surfactant granules can readily be produced in conventional tablet presses.
Anionic, nonionic, cationic and/or amphoteric surfactants or mixtures thereof may be used in the detergent tablets according to the invention. Mixtures of anionic and nonionic surfactants are preferred from the applicational point of view. The tablets have a total surfactant content of 5 to 60% by weight, based on tablet weight, 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 Cs_~3 alkyl benzenesulfonates, olefin sulfonates, i.e. mixtures of alkene and hydroxyalkane sulfonates, and the disulfonates obtained, for example, from C~2_~$ monoolefins with an internal or terminal double bond by sulfonation with gaseous sulfur trioxide and subsequent alkaline or acidic 5 hydrolysis of the sulfonation products. Other suitable surfactants of the sulfonate type are the alkane sulfonates obtained from C~2_~$ alkanes, for example by sulfochlorination or sulfoxidation and subsequent hydrolysis or neutralization. The esters of a-sulfofatty acids (ester sulfonates), for example the a-sulfonated methyl esters of hydrogenated coconut oil, palm 10 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 moles of glycerol. Preferred sulfonated fatty acid glycerol esters are the sulfonation products of saturated fatty acids containing 6 to 22 carbon atoms, for example caproic acid, caprylic acid, capric acid, myristic acid, lauric acid, palmitic acid, stearic acid or behenic acid.
Preferred alk(en)yl sulfates are the alkali metal salts and, in particular, the sodium salts of the sulfuric acid semiesters of C~2_~8 fatty alcohols, for example cocofatty alcohol, tallow fatty alcohol, lauryl, myristyl, cetyl or stearyl alcohol, or Coo-2o oxoalcohols and the corresponding semiesters of secondary alcohols with the same chain length. Other preferred alk(en)yl sulfates are those with the chain length mentioned which contain a synthetic, linear alkyl chain based on a petrochemical and which are similar in their degradation behavior to the corresponding compounds based on oleochemical raw materials. C~2_~6 alkyl sulfates, C~2_~5 alkyl sulfates and C~4_~5 alkyl sulfates are preferred from the point of view of washing technology. Other suitable anionic surfactants are 2,3-alkyl sulfates which may be produced, for example, in accordance with US
3,234,258 or US 5,075,041 and which are commercially obtainable as products of the Shell Oil Company under the name of DAN~.
The sulfuric acid monoesters of linear or branched C~_2~ alcohols ethoxylated with 1 to 6 moles of ethylene oxide, such as 2-methyl branched C9_» 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 quantities of 1 to 5% by weight, in dishwashing detergents.
Other suitable anionic surfactants are the salts of alkyl sulfosuccinic acid which are also known as sulfosuccinates or as sulfosuccinic acid esters and which represent monoesters and/or diesters of sulfosuccinic acid with alcohols, preferably fatty alcohols and, more particularly, ethoxylated fatty alcohols. Preferred sulfosuccinates contain C$_~$ fatty alcohol residues or mixtures thereof. Particularly preferred sulfosuccinates contain a fatty alcohol residue derived from ethoxylated fatty alcohols which, considered in isolation, represent nonionic surfactants (for a description, see below). Of these sulfosuccinates, those of which the fatty alcohol residues are derived from narrow-range ethoxylated fatty alcohols are particularly preferred. Alk(en)yl succinic acid preferably containing 8 to 18 carbon atoms in the alk(en)yl chain or salts thereof may also be used.
Other suitable anionic surfactants are, in particular, soaps. Suitable soaps are saturated fatty acid soaps, such as the salts of lauric acid, myristic acid, palmitic acid, stearic acid, hydrogenated erucic acid and behenic acid, and soap mixtures derived in particular from natural fatty acids, for example coconut oil, palm kernel oil or tallow fatty acids.
The anionic surfactants, including the soaps, may be present in the form of their sodium, potassium or ammonium salts and as soluble salts of organic bases, such as mono-, di- or triethanolamine. The anionic surfactants are preferably present in the form of their sodium or potassium salts and, more preferably, in the form of their sodium salts.

Preferred nonionic surfactants are alkoxylated, advantageously ethoxylated, more especially primary alcohols preferably containing 8 to 18 carbon atoms and, on average, 1 to 12 moles of ethylene oxide (EO) per mole of alcohol, in which the alcohol component may be linear or, preferably, methyl-branched in the 2-position or may contain linear and methyl-branched residues in the form of the mixtures typically present in oxoalcohol residues. However, alcohol ethoxylates containing linear residues of alcohols of native origin with 12 to 18 carbon atoms, for example coconut oil, palm oil, tallow fatty or oleyl alcohol, and on average 2 to 8 EO per mole of alcohol are particularly preferred. Preferred ethoxylated alcohols include, for example, C~2_~4 alcohols containing 3 EO
or 4 EO, C9_~~ alcohol containing 7 EO, C~3_~5 alcohols containing 3 EO, 5 EO, 7 EO or 8 EO, C12_~$ alcohols containing 3 EO, 5 EO or 7 EO and mixtures thereof, such as mixtures of C~2_~4 alcohol containing 3 EO and C~2_~$ 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 ethoxylates have a narrow homolog distribution (narrow range ethoxylates, NRE). In addition to these nonionic surfactants, fatty alcohols containing more than 12 EO
may also be used, examples including tallow fatty alcohol containing 14 EO, 25 EO, 30 EO or 40 EO.
Another class of nonionic surfactants which may advantageously be used are alkyl glycosides corresponding to 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. The degree of oligomerization x, which indicates the distribution of monoglycosides and oligoglycosides, is a number of 1 to 10, preferred values for x being 1.2 to 1.4.
Another class of preferred nonionic surfactants which may be used either as sole nonionic surfactant or in combination with other nonionic surfactants are alkoxylated, preferably ethoxylated or ethoxylated and ' CA 02297443 2000-O1-28 propoxylated, fatty acid alkyl esters preferably containing 1 to 4 carbon atoms in the alkyl chain, more especially the fatty acid methyl esters which are described, for example, in Japanese patent application JP 581217598 or which are preferably produced by the process described in International patent application WO-A-90113533.
Nonionic surfactants of the amine oxide type, for example N-cocoalkyl-N,N-dimethylamine oxide and N-tallowalkyl-N,N-dihydroxyethyl-amine oxide, and the fatty acid alkanolamide type are also suitable. The quantity in which these nonionic surfactants are used is preferably no more than the quantity in which the ethoxylated fatty alcohols are used and, more preferably, no more than half that quantity.
Other suitable surfactants are polyhydroxyfatty acid amides corresponding to formula (I):
R' R-CO-N-[Z] (I) in which RCO is an aliphatic acyl group containing 6 to 22 carbon atoms, R' is hydrogen, an alkyl or hydroxyalkyl group containing 1 to 4 carbon atoms and [Z] is a linear or branched polyhydroxyalkyl group containing 3 to 10 carbon atoms and 3 to 10 hydroxyl groups. The polyhydroxyfatty acid amides are known substances which may normally be obtained by reductive amination of a reducing sugar with ammonia, an alkylamine or an alkanolamine and subsequent acylation with a fatty acid, a fatty acid alkyl ester or a fatty acid chloride.
The group of polyhydroxyfatty acid amides also includes compounds corresponding to formula (II):
R'-O-R2 R-CO-N-[Z] (I I) in which R is a linear or branched alkyl or alkenyl group containing 7 to 12 carbon atoms, R' is a linear, branched or cyclic alkyl group or an aryl group containing 2 to 8 carbon atoms and R2 is a linear, branched or cyclic alkyl group or an aryl group or an oxyalkyl group containing 1 to 8 carbon atoms, C» alkyl or phenyl groups being preferred, and [Z) is a linear polyhydroxyalkyl 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, fructose, maltose, lactose, galactose, mannose or xylose. The N-alkoxy- or N-aryloxy-substituted compounds may then be converted into the required polyhydroxyfatty acid amides by reaction with fatty acid methyl esters in the presence of an alkoxide as catalyst, for example in accordance with the teaching of International patent application WO-A-95/07331.
According to the invention preferred detergent tablets contain anionic and nonionic surfactant(s). Performance-related advantages can arise out of certain quantity ratios in which the individual classes of surfactant are used.
For example, particularly preferred detergent tablets are those in which the ratio of anionic surfactants) to nonionic surfactants) is between 10:1 and 1:10, preferably between 7.5:1 and 1:5 and more preferably between 5:1 and 1:2.
Certain performance-related advantages can be obtained if certain classes of surfactant are not present in certain phases of the detergent tablets or in any of the phases. In another important embodiment of the present invention, therefore, at least one phase of the tablets is free from nonionic surfactants.
Conversely, however, a positive effect can also be obtained if individual phases or the tablet as a whole, i.e. all the phases, contain certain surfactants. The introduction of the alkyl polyglycosides described above has proved to be advantageous so that detergent tablets in which at least one phase contains alkyl polyglycosides are preferred.

As with the nonionic surfactants, the omission of anionic surfactants from individual phases or from all the phases can also result in detergent tablets which are better suited to certain applications. According to the invention, therefore, detergent tablets in which at least one phase is free 5 from anionic surfactants are also possible.
Besides the detersive substances, builders are the most important ingredients of detergents. The detergent tablets according to the invention may contain any of the builders typically used in detergents, i.e. in particular zeolites, silicates, carbonates, organic co-builders and -10 providing there are no ecological objects to their use - the phosphates.
Suitable crystalline layer-form sodium silicates correspond to the general formula NaMSiXOZX+~y H20, where M is sodium or hydrogen, x is a number of 1.9 to 4 and y is a number of 0 to 20, preferred values for x being 2, 3 or 4. Crystalline layer silicates such as these are described, for 15 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 F~-sodium disilicates Na2Si205y H20 are particularly preferred, ~i-sodium disilicate being obtainable, for example, by the process described in International patent application WO-A- 91108171.
Other useful builders are amorphous sodium silicates with a modulus (Na20:Si02 ratio) of 1:2 to 1:3.3, preferably 1:2 to 1:2.8 and more preferably 1:2 to 1:2.6 which dissolve with delay and exhibit multiple wash cycle properties. The delay in dissolution in relation to conventional amorphous sodium silicates can have been obtained in various ways, for example by surface treatment, compounding, compacting or by overdrying. In the context of the invention, the term "amorphous" is also understood to encompass "X-ray amorphous". In other words, the silicates do not produce any of the sharp X-ray reflexes typical of crystalline substances in X-ray diffraction experiments, but at best one or more maxima of the scattered X-radiation which have a width of several degrees of the diffraction angle. However, particularly good builder properties may even be achieved where the silicate particles produce crooked or even sharp diffraction maxima in electron diffraction experiments. This may be interpreted to mean that the products have microcrystalline regions between 10 and a few hundred nm in size, values of up to at most 50 nm and, more particularly, up to at most 20 nm being preferred. So-called X-ray amorphous silicates such as these, which also dissolve with delay in relation to conventional waterglasses, are described for example in German patent application DE-A-44 00 024. Compacted amorahous 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.
According to the invention, it is also possible to use, for example, a commercially obtainable co-crystallizate of zeolite X and zeolite A (ca.
80% by weight zeolite X) which is marketed by CONDEA Augusta S.p.A.
under the name of VEGOBOND AX~ and which may be described by the following formula:
nNa20 ~ (1-n)K20 ~ AI203 ~ (2 - 2.5)Si02 ~ (3.5 - 5.5) H20.
The zeolite may be used both as a builder in a granular compound and also to "powder" the entire mixture to be tabletted, both methods normally being used to incorporate the zeolite in the premix. Suitable zeolites have a mean particle size of less than 10 ~m (volume distribution, as measured by the Coulter Counter Method) and contain preferably 18 to 22% by weight and more preferably 20 to 22% by weight of bound water.
The generally known phosphates may of course also be used as builders providing their use should not be avoided on ecological grounds.
The sodium salts of the orthophosphates, the pyrophosphates and, 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 its 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.
Detergent tablets are produced by the application of pressure to a mixture to be tabletted which is accommodated in the cavity of a press. In the most simple method of tablet production - hereinafter referred to simply as tabletting - the mixture to be tabletted is compressed directly, i.e. without preliminary granulation. The advantages of this so-called direct tabletting are its simple and inexpensive application because no other process steps and hence no other items of equipment are involved.
However, these advantages are offset by disadvantages. Thus, a powder mixture which is to be directly tabletted must possess adequate plastic deformability and good flow properties and must not show any tendency to separate during storage, transportation and filling of the die.
Unfortunately, these three requirements are very difficult to satisfy with many mixtures so that direct tabletting is often not applied, particularly in the production of detergent tablets. Accordingly, the normal method of producing detergent tablets starts out from powder-form components ("primary particles") which are agglomerated or granulated by suitable methods to secondary particles with larger particle diameters. These granules or mixtures of different granules are then mixed with individual powder-form additives and the resulting mixtures are tabletted. Depending on the composition of the phases of the multiphase detergent tablets, the die is filled in steps with different premixes. In the production of multilayer tablets, the application of light pressure between the fillings with premixes can have advantages for the next step. In the production of ring/core tablets or jacket tablets, precompression and shaping/forming such as this is even almost indispensable.
According to the invention, preferred detergent tablets are obtained by tabletting particulate premixes of at least one batch of surfactant-containing granules and at least one subsequently added powder-form component. The surfactant-containing granules may be produced by conventional granulation processes, such as mixer and pan granulation, fluidized bed granulation, extrusion, pelleting or compacting. It is of advantage so far as the subsequent detergent tablets are concerned if the premixes to be tabletted have a bulk density approaching that of standard compact detergents. In one particularly preferred embodiment, the premix to be tabletted has a bulk density of at least 500 g/I, preferably of at least 600 g/I and more preferably above 700 g/I. Another advantage can arise out of a relatively narrow particle size distribution of the surfactant granules used. According to the invention, preferred detergent tablets are those in which the granules have particle sizes of 10 to 4,000 Ilm, preferably between 100 and 2,000 pm and more preferably between 600 and 1,400 Nm.
The particle size distribution of the powder-form aftertreatment components subsequently added can also be varied, detergent tablets where the powder-form components) subsequently added contain the cellulose-containing disintegration aid being preferred.
Before the particulate premix is compressed to form detergent tablets, it may be "powdered" with fine-particle surface treatment materials.
This can be of advantage to the quality and physical properties of both the premix (storage, tabletting) and the final detergent tablets. Fine-particle powdering materials have been known for some time in the art, zeolites, silicates and other inorganic salts generally being used. However, the premix is preferably "powdered" with fine-particle zeolite, zeolites of the faujasite type being preferred. In the context of the present invention, the expression "zeolite of the faujasite type" encompasses all three zeolites which form the faujasite subgroup of zeolite structural group 4 (cf. Donald W. Breck: "Zeolite Molecular Sieves" John Wiley & Sons, New York/London/Sydney/Toronto, 1974, page 92). Besides zeolite X, there-fore, zeolite Y and faujasite and mixtures of these compounds may also be used, pure zeolite X being preferred. Mixtures or co-crystallizates of zeolites of the faujasite type with other zeolites, which do not have to belong to zeolite structural group 4, may also be used for powdering, in which case at least 50% by weight of the powdering material advantageously consists of a zeolite of the faujasite type.
According to the invention, preferred detergent tablets consist of a particulate premix containing granular components and subsequently incorporated powder-form components, the, or one of the, fine-particle components subsequently incorporated being a zeolite of the faujasite type with particle sizes below 100 Nm, preferably below 10 Nm and more preferably below 5 Nm and making up at least 0.2% by weight, preferably at least 0.5% by weight and more preferably more than 1 % by weight of the premix to be compressed.
The fine-particle aftertreatment components with the particle sizes mentioned above may be dry-mixed with the premix to be tabletted.
However, it is also possible and preferred to "stick" them onto the surface of the relatively coarse particles by addition of small quantities of liquid components. These powdering techniques are widely described in the prior art literature and familiar to the expert. Liquid components suitable as adhesion promoters for the powdering materials are, for example, nonionic surfactants or aqueous solutions of surfactants or other detergent ingredients. In one preferred embodiment of the invention, perfume is used as the liquid component for promoting the adhesion of the powdering materials.
Besides the above mentioned ingredients (surfactants, builders and disintegration aids), the detergent tablets according to the invention may contain other typical detergent ingredients from the group of bleaching agents, bleach activators, enzymes, perfumes, perfume carriers, fluorescers, dyes, foam inhibitors, silicone oils, redeposition inhibitors, optical brighteners, discoloration inhibitors, dye transfer inhibitors and corrosion inhibitors.
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 5 are, for example, sodium percarbonate, peroxypyrophosphates, citrate perhydrates and H202-yielding peracidic salts or peracids, such as perbenzoates, peroxophthalates, diperazelaic acid, phthaloiminoperacid or diperdodecane dioic acid.
In order to obtain an improved bleaching effect where washing is 10 carried out at temperatures of 60°C or lower, bleach activators may be incorporated in one or more phases. 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 15 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 alkylene-diamines, more particularly tetraacetyl ethylenediamine (TAED), acylated triazine derivatives, more particularly 1,5-diacetyl-2,4-dioxohexahydro-20 1,3,5-triazine (DADHT), acylated glycolurils, more particularly tetraacetyl glycoluril (TAGU), N-acylimides, more particularly N-nonanoyl succinimide (NOSI), 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-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 complexes with nitrogen-containing tripod ligands and cobalt-, iron-, copper- and ruthenium-ammine complexes may also be used as bleach catalysts.
Suitable enzymes are those from the class of proteases, lipases, amylases, cellulases and mixtures thereof. Enzymes obtained from bacterial strains or fungi, such as Bacillus subtilis, Bacillus licheniformis and Streptomyces griseus are particularly suitable. Proteases of the subtilisin type are preferably used, proteases obtained from Bacillus lentus being particularly preferred. Of particular interest in this regard are 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 protease, lipase and cellulase, but especially cellulase-containing mixtures. Peroxidases or oxidases have also been successfully used 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 enzymes, enzyme mixtures or enzyme granules in the tablets according to the invention may be, for example, about 0.1 to 5% by weight and is preferably from 0.1 to about 2% by weight.
In addition, the detergent tablets 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 hydroxy-propoxyl groups, based on the nonionic cellulose ether, and the polymers of phthalic acid and/or terephthalic acid known from the prior art or derivatives thereof, more particularly polymers of ethylene terephthalates and/or polyethylene glycol terephthalates or anionically and/or nonionically modified derivatives thereof. Of these, the sulfonated derivatives of phthalic acid and terephthalic acid polymers are particularly preferred.
The tablets may contain derivatives of diaminostilbenedisulfonic 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)-stilbene-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 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)-diphen-yl, may also be present. Mixtures of the brighteners mentioned above may also be used.
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 with a visually and sensorially "typical and unmistakable" product. Suitable perfume oils or fragrances include individual fragrance compounds, for example synthetic products of the ester, ether, aldehyde, ketone, alcohol and hydrocarbon type. Fragrance compounds of the ester type are, for example, benzyl acetate, phenoxyethyl isobutyrate, p-tert.butyl cyclohexyl acetate, linalyl acetate, dimethyl benzyl carbinyl acetate, phenyl ethyl acetate, linalyl benzoate, benzyl formate, ethyl methyl phenyl glycinate, allyl cyclohexyl propionate, styrallyl propionate and benzyl salicylate. The ethers include, for example, benzyl ethyl ether; the aldehydes include, for example, the linear alkanals containing 8 to 18 carbon atoms, citral, citronellal, citronellyloxy-acetaldehyde, cyclamen aldehyde, hydroxycitronellal, lilial and bourgeonal;
the ketones include, for example, the ionones, a-isomethyl ionone and methyl cedryl ketone; the alcohols include anethol, citronellol, eugenol, geraniol, linalool, phenyl ethyl alcohol and terpineol and the hydrocarbons include, above all, the terpenes, such as limonene and pinene. However, mixtures of various fragrances which together produce an attractive fragrance note are preferably used. Perfume oils such as these may also contain natural fragrance 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 softeners 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.
The fragrances may be directly incorporated in the detergents according to the invention, although it can also be of advantage to apply the fragrances to supports which strengthen the adherence of the perfume to the washing and which provide the textiles with a long-lasting fragrance through a slower release of the perfume. Suitable support materials are, for example, cyclodextrins, the cyclodextrin/perfume complexes optionally being coated with other auxiliaries.
In order to improve their aesthetic impression, the detergent tablets according to the invention may be colored with suitable dyes. Preferred dyes, which are not difficult for the expert to choose, have high stability in storage, are not affected by the other ingredients of the detergents or by light and do not have any pronounced substantivity for textile fibers so as not to color them. Since the present invention relates to multiphase detergent tablets, considerable significance attaches to the coloring of individual phases in order to underscore the differences in active character between individual phases. Examples of the effectivenes of such coloring and of the success of relevant claims are sufficiently known from the advertizing of denture cleaning preparations.
The tablets according to the invention are produced by first dry-mixing the constituents of the individual phases, which may be completely partly pregranulated, and then forming/shaping, more particularly tabletting, the resulting mixtures using conventional processes for the production of multiphase tablets. To produce the tablets according to the invention, the premixes are 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), plastic deformation and ejection.
The tabletting process is carried out in commercially available tablet presses which, in principle, may be equipped with single or double punches. In 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 table. The number of dies varies - according to model - between 6 and 55, although even larger dies are commercially available. Top and bottom punches are associated with each die on the die table, the tabletting pressures again being actively built up not only by the top punch or bottom punch, but also by both punches. The die table and the punches move about a common vertical axis, the punches being brought into the filling, compaction, plastic deformation and ejection positions by means of curved guide rails. At those places where the punches have to be raised or lowered to a particularly significant extent (filling, compaction, ejection), 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 premix can be individually adjusted through the 5 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 or more filling shoes. To produce two-layer or multiple-layer tablets, several filling shoes are arranged one behind the other without the lightly 10 compacted first layer being ejected before further filling. Given suitable process control, shell and bull's-eye tablets - which have a structure resembling an onion skin - can also be produced in this way. In 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 15 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.
Tabletting machines suitable for the purposes of the invention can 20 be obtained, for example, from the following companies: Apparatebau Holzwarth GbR, Asperg, Wilhelm Fette GmbH, Schwarzenbek, Hofer GmbH, Weil, KILIAN, Cologne, KOMAGE, Kell am See, KORSCH Pressen GmbH, Berlin, Mapag Maschinenbau AG, Bern (Switzerland) and Courtoy N.V., Halle (BE/LU). One example of a particularly suitable tabletting 25 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, consisting always of several phases, i.e. layers, inclusions or cores and rings. Suitable shapes are virtually any easy-to-handle shapes, for example slabs, bars, cubes, squares and corresponding shapes with flat sides and, in particular, cylindrical forms of circular or oval cross-section.
This last embodiment encompasses shapes from tablets to compact cylinders with a height-to-diameter ratio of more 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 possible to form pressings which combine several such units in a single pressing, smaller portioned units being easy to break off in particular through the 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 pressings 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 to use the detergent tablets in conjunction with a dosing aid.
Another preferred multiphase 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 " multiphase bar" at the predetermined weak spots, which the short thin segments represent, and introduced into the machine. This "bar"
principle can also be embodied in other geometric forms, for example vertical triangles which are only joined to one another at one of their longitudinal sides. In this case, it is appropriate for optical reasons to make the base of the triangle, by which the individual segments are interconnected, as one phase while the apex forms the second phase. In this embodiment, different coloring of the two phases is particularly attractive.
After pressing, the detergent tablets have high stability. The fracture resistance of cylindrical tablets can be determined via the diametral fracture stress. This in turn can be determined in accordance with the following equation:

a=
~Dt where a represents the diametral fracture stress (DFS) in Pa, P is the force in N which leads to the pressure applied to the tablet that results in fracture thereof, D is the diameter of the tablet in meters and t is its height.
Examples Premixes were prepared by mixing surfactant-containing granules with powder-form aftertreatment components and tabletted in a Korsch tablet press to form two-phase detergent tablets. Surfactant granules 1, 2 and 3 had been produced in a 130-liter plowshare mixer (Gebruder Lodige, Paderborn) and then dried in a fluidized-bed dryer. After the coarse fractions (>_ 1.6 mm) and the fine particles (<_ 0.4 mm) had been removed by sieving, the surfactant granules were mixed with the aftertreatment components in a paddle mixer.
The composition of the surfactant granules is shown in Table 1.

' CA 02297443 2000-O1-28 Table 1: Surfactant granules [% by weight]
G~trw''u~~a$~'~ainiutesGr~~c~les:

.: ~. r.. ~'.~~ ~
. .
, 3 ~ .. , , , ~ '. < ., , 21.2 18.6 19.4 , C9_~3 alkyl benzenesulfonate C~2_~$ fatty alcohol sulfate8.5 5.4 5.2 C~2_~8 fatty alcohol + 7 - 5.7 4.8 EO

C~2_~s alkyl-1,4-glycoside - - 1.0 Soap 1.6 1.6 1.6 Sodium carbonate 17.0 16.6 17.0 Sodium silicate 5.6 5.4 5.6 Zeolite A (water-free active28.5 29.9 28.5 substance) Optical brightener 0.3 0.3 0.3 Na hydroxyethane-1,1-diphosphate0.8 0.8 0.8 Acrylic acid/maleic acid 5.6 5.4 5.6 copolymer) Water, salts Balance Balance Balance Two-layer detergent tablets were produced from the premixes (surfactant granules + aftertreatment components) in a Korsch rotary press, the first layer making up 75% and the second layer 25% of the total weight of each tablet. The diameter of the tablets was 44 mm, the total quantity of cellulose was always 5% by weight, based on the tablet as a whole.
Tables 2, 3 and 4 below show the phase compositions of the detergent tablets. The figures in the columns of the Table represent the quantity of the particular ingredient in the particular phase of the tablet, i.e.
the figures in each column add up to 100%. The quantity of the particular ingredient in the tablet as a whole can easily be calculated from the percentage content of the individual phases in the tablet. Commensurate with the different tablet weights (37.5 g t 1 %,caused by slight variations in the feed of the premix to the die of the press), the tablet hardnesses varied by about ca. t 10%, the disintegration times by ca. 5 seconds. The tablet hardnesses and disintegration times are also shown in the Tables.
Table 2: Detergent tablets - composition [% by weight], physical properties Ex~m p~le Invention Comparison Example Layer Layer Layer Layer Granules 1 - 57.1 70.0 56.7 71.3 Sodium perborate monohydrate23.7 - 23.7 -Tetraacetyl ethylenediamine9.7 - g.7 Enzyme granules* - 10.0 - 10.0 Foam inhibitor 0.8 11.7 0.8 11.7 Repelotex SRP 4** 1.5 - 1.5 -Perfume 0.7 - 0.7 -Zeolite A 2.0 2.0 2.0 2.0 Cellulose** 4.6 6.3 5.0 5.0 ~ ~rfa~tant ~ont~nt , , 17.$"Tfa 21.x'!I17.751c~ 22:32I
;

Sitt~fiaCt~nt cr~nter~t 1$.$>la 'f ~f~~~~~~ 8:89la iffer~tlC~ in'sUrf~Ct~t 4.04 lo ~t3~t~:r>rt ' /a ,~
. -s,o :. 4b7 ,, : ~: .
_.

. , ~~#ac~ s~~ sur~~t,~~lr.g~"~tr~ut~~ 1 '~~:'~.2-.
. ;E 1123 ; a 1 ~
C~Irulc~,r~o*~' Y 't ~:'~T.
y.3"~' ef,, , Tablet hardness 36-48 39-47 N N

Disintegration time 17-23 33-41 secs. secs.

* Enzyme granules of protease, cellulase, amylase, lipase on a support (starch), coated ** Repelotex SRP 4 is a terephthalic acid/ethylene glycol, polyethylene glycol ester made by Rhone Poulenc *** Arbocel~ TF 30 HG (Rettenmaier), particle size: 2% <200 Nm, 2%
5 >200 Nm, 11 % >400 Nm, 23% > 600 Vim, 62% > 800 Vim, 0% > 1.2 mm Table 3: Detergent tablets - composition [% by weight], physical properties ~~~ ~~ 2' Invention Comparison Example Layer Layer Layer Layer Granules 2 56.9 70.5 56.6 71.3 Sodium perborate monohydrate23.7 - 23.7 -Tetraacetyl ethylenediamine2.5 21.7 2.5 21.7 Enzyme granules 3.3 - 3.3 -Foam inhibitor 4.7 - 4.7 -Repelotex SRP 4 1.5 - 1.5 -Perfume 0.7 - 0.7 -Zeolite A 2.0 2.0 2.0 2.0 Cellulose 4.7 5.8 5.0 5.0 5urfa~tartt cner~t 17.61% 2ZwtI7,!'~?.7~/n 2.32~~~

ur~actant~~rite~t.~~abl~~ ~t6.8'~/Q 't$:8 7I
, ': ' '= .
~_ . ~ ~ .

~3i~'er~nce ir~,~~r~~fctar~t 4.2fi~~ ~fit~%:
content ; _ E:, . r , ~..
Fa~icx.a~~r~at~r~~~ranu~~s, ~1:1.~4 ~.
:E ;,, :. -l~t.2fi C~lu~~se r~tia~ ~ :1 ~

E;.

Tablet hardness 36-48 37-49 N N

Disintegration time 20-28 38-45 secs. secs.

Table 4: Detergent tablets - composition [% by weight), physical properties ~~~r ripl~
~

Invention Comparison Example Layer Layer Layer Layer Granules 3 56.8 70.8 56.8 70.8 Sodium perborate monohydrate19.8 11.7 19.8 11.7 Tetraacetyl ethylenediamine9.7 - g.7 _ Enzyme granules - 10.0 - 10.0 Foam inhibitor 4.7 - 4.7 -Repelotex SRP 4 1.5 - 1.5 -Perfume 0.7 - 0.7 -Zeolite A 2.0 2.0 2.0 2.0 Cellulose 4.8 5.5 5.0 5.0 ~rfac~a nt aar~tent g 18* ~ ~* fifil:'t 22fifil ~~ .
~

8%~

~~rfac~ant ~nte~ (tabl~t~ .',~f9a3 t~% ."~9:3 i~~-~ - ;

C~ifferert~~ ire urfa~tar~t~-.4fifo 4:48%
c~nt~nt -Ratir~o~~urf~rt~r~~,c~rnr~teEj,'t:1. ~~.25 G~lluias~ ratip ~:~.'~. 1:1 .

Tablet hardness 43-51 38-47 N N

Disintegration time 14-19 ~28-37 secs. secs.

It can be seen that, despite the same content of cellulose-containing disintegration aid (based on the tablet as a whole), the tablets according to the invention have far shorter disintegration times than the Comparison Examples.

Claims (23)

1. A detergent tablet having at least two phases comprising compacted detergent granules comprising surfactant(s), builder(s) and optionally other detergent ingredients, wherein the surfactant content of the individual phases of the tablet varies by more than 3% by weight, based on the weight of the individual phase, a cellulose-containing disintegration aid containing at most 10% by weight of particles under 200 µm in size being present in larger quantities in the phase(s) with the higher surfactant content than in the phase(s) with the lower surfactant content.

2. The detergent tablet as claimed in claim 1, wherein the content of cellulose-containing disintegration aid in the phase(s) richer in surfactant is higher by at least 2.5% by weight, based on the weight of the disintegration aid, than in the phase(s) with the lower surfactant content.

3. The detergent tablet as claimed in claim 1, wherein the disintegration times of the layers differ from one another by at most 5 seconds.

4. The detergent tablet as claimed in claim 1, wherein the cellulose-containing disintegration aid consists essentially of cellulose fibers with a primary fiber length of under 100 µm which have been compacted to a particle spectrum of 200 to 2000 µm.

5. The detergent tablet as claimed in claim 1, wherein the quantity ratio of the cellulose-containing disintegration aid between the individual phases is greater than the quantity ratio of the surfactants between the respective phases.

6. The detergent tablet as claimed in claim 1, wherein the cellulose-containing disintegration aid present contains less than 20% by weight of particles with a particle size below 400 µm.

7. The detergent tablet as claimed in claim 1, wherein the cellulose-containing disintegration aid present in the tablet contains less than 20%
by weight of particles with a particle size above 1200 µm.

8. The detergent tablet as claimed in claim 1, wherein at least 60% by weight of the cellulose-containing disintegration aid present in the tablet consists of cellulose.

9. The detergent tablet as claimed in claim 1, wherein the phases of the tablet are in the form of layers.

10. The detergent tablet as claimed in claim 1, wherein the surfactant(s) are introduced into the phases of the tablet through at least one batch of surfactant-containing granules.

11. The detergent tablet as claimed in claim 10, wherein the same surfactant granules are used in all phases of the tablet.

12. The detergent tablet as claimed in claim 10, wherein the tablet comprises at least two layers which contain the same surfactant granules in different quantities.

13. The detergent tablet as claimed in claim 1, wherein the tablet contains anionic and nonionic surfactant(s).

14. The detergent tablet as claimed in claim 13, wherein the ratio of anionic surfactant(s) to nonionic surfactant(s) is between 10:1 and 1:10.

15. The detergent tablet as claimed in claim 1, wherein at least one phase of the tablet is free from nonionic surfactants.

16. The detergent tablet as claimed in claim 1, wherein at least one phase of the tablet contains alkyl polyglycosides.

17. The detergent tablet as claimed in claim 1, wherein at least one phase of the tablet is free from anionic surfactants.

18. The detergent tablet as claimed in claim 1, wherein the tablet is obtained by tabletting of a particulate premix of at least one batch of surfactant-containing granules and at least one subsequently incorporated powder-form component.

19. The detergent tablet as claimed in claim 18, wherein the granules are produced by a process selected from the group consisting of mixer granulation, pan granulation, fluidized bed granulation, extrusion, pelleting or compacting.

20. The detergent tablet as claimed in claim 18, wherein the granules have particle sizes of 10 to 4,000 µm.

21. The detergent tablet as claimed in claim 18, wherein the powder form component(s) subsequently incorporated contain the cellulose-containing disintegration aid.

22. The detergent tablet as claimed in claim 18, wherein the premix to be tabletted has a bulk density of at least 500 g/l.

23. The detergent tablet as claimed in claim 1, wherein the tablet additionally contains at least one substance selected from the group consisting of builders, bleaching agents, bleach activators, enzymes, pH
regulators, perfumes, perfume carriers, fluorescers, dyes, foam inhibitors, silicone oils, redoposition inhibitors, optical brighteners, discoloration inhibitors, dye transfer inhibitors and corrosion inhibitors.