CA2302141A1 - A builder-containing tablet - Google Patents

Abstract

Builder-containing tablets which contain an additive containing a crystalline layer sodium silicate and a copolymeric polycarboxylic acid can be produced without the use of additional tabletting aids or additional disintegrators and are still comparable in their dissolving behavior to tablets where such components are individually added, but which additionally contain tabletting aids and disintegrators. In addition, such tablets can be obtained with a comparable hardness at lower tabletting pressures. Water softening tablets in particular can thus have a particularly high active substance content because there is largely no need to use auxiliaries which do not contribute towards the water softening function.

Description

A Builder-containing Tablet This invention relates to builder-containing tablets containing crystalline layer silicates which are suitable for washig or cleaning or for softening water.
Tablets have a number of advantages over powders, including easy dosing and minimal packaging volume. However, problems arise out of the fact that relatively high tabletting pressures have to be applied in the tabletting of the powders in order to achieve adequate dimensional stability and fracture resistance. On account of the high compression to which they are subjected, therefore, tablets often have unsatisfactory disintegrating and dissolving properties in use. In order to be able to control problems such as these, tabletting aids are generally added to the actual active substances. The tabletting aids in question are, for example, polyethylene glycols, typically with molecular weights of 1000 to 6000 g/mole, which normally make up from 2 to 6% by weight of the tablet formulation as a whole. In addition, to ensure that the tablets dissolve rapidly, so-called disintegrators are added. These disintegrators, which are normally used in quantities of 3 to 30% by weight of the tablets, include for example microcrystalline cellulose and swellable synthetic polymers, such as polyvinyl pyrrolidone. Both the tabletting aids and the disintegrators are additives which do not themselves contribute towards the effect of the particular tabletted composition. Accordingly, such additives reduce the active-substance content of the tablets.
Accordingly, there is still a need for active substances which also act as tabletting aids or disintegrators and thus eliminate the need for special tabletting aids and disintegrators.
It has now been found that tablets in which crystalline layer silicates and certain copolymers are present in the form of a suitably prepared ' . CA 02302141 2000-03-27 compound do not have to contain further auxiliaries of the type in question and can still be produced with relatively low tabletting pressures without any adverse effect on their fracture resistance. The tablets show excellent dissolving behavior, even in the absence of special disintegrators.
Tablets containing crystalline layer silicates have long been known per se. Patent application WO 95121908 describes tablets containing amorphous, partly crystalline and/or crystalline layer-form sodium silicates with the following formula:
Na2Six02X.., ~yH20 where x is a number of 1.9 to 4 and y is a number of 0 to 20, in quantities of 2 to 100% by weight. A water softening tablet described in this application contains, for example, 20 to 80% by weight of the crystalline layer silicates, optionally up to 80% by weight of zeolite and/or phosphate, optionally up to 50% by weight of polycarboxylate, up to 15% by weight of polymeric poly-carboxylates and up to 30% by weight of surfactants. The tablet described in one Example contains methyl hydroxypropyl cellulose as disintegrator.
EP-A-812 808 describes water softening tablets which may contain up to 45% by weight of crystalline layer silicates and which additionally contain a polybasic carboxylic acid or salt, carbonate andlor bicarbonate and polymer. The tablets also contain 1 to 6% by weight of binder and up to 15% by weight of disintegrator.
It has now been found that tablets which, besides other ingredients, contain a granular additive which in turn contains a crystalline layer silicate and (co)polymeric polycarboxylic acid as key ingredients can be produced at moderate tabletting pressures, even without the use of additional tabletting aids or disintegrators, and are readily soluble.
In a first embodiment, therefore, the present invention relates to tablets containing builders and optionally other ingredients of detergents or ' CA 02302141 2000-03-27 to phases of such tablets, characterized in that they contain a powder-form or granular additive which contains a crystalline layer silicate corresponding to general formula (I):
NaMSiX02X+~ ~ yHzO (I) in which M is sodium or hydrogen, x is a number of 1.9 to 2.2 and y is a number of 0 to 33, and (co)polymeric polycarboxylic acid as key ingredients, the tablets containing no additional disintegrator without a builder effect and at most 2% by weight of additional tabletting aid.
Crystalline layer silicates corresponding to formula (I) are marketed, for example, by Clariant GmbH (Germany) under the trade name Na-SKS, including for example Na-SKS-1 (Na2Si220a5~xH20, kenyaite) Na-SKS-2 (Na2Si,4029.xH20, magadiite), Na-SKS-3 (Na2Si80~~~xH20), Na-SKS-4.
(Na2Si409~xH20, makatite).
Compositions particularly suitable for the purposes of the invention are those containing crystalline layer silicates corresponding to formula (I) in which x is 2. Of these, Na-SKS-5 (a'-Na2Si205), Na-SKS-7 (~ -NazSi205 natrosilite), Na-SKS-9 (NaHSi205 ~ H20), Na-SKS-10 (NaHSi205 ~ 3H20, kanemite), Na-SKS-11 (T~-Na2Si205) and Na-SKS-13 (NaHSi205), but especially Na-SKS-6 ( s-Na2Si205), are particularly suitable. An overview of crystalline layer silicates can be found, for example, in the articles published in "Hoechst High Chem Magazin 1411993", pages 33-38 and in "Seifen-Ole-Fette-Wachse", Vol. 116, No. 20J1990", pages 805-808.
According to the invention, the crystalline layer silicates corresponding to formula (I) are at least partly introduced into the tablets according to the invention through the builder additive used in accordance with the invention. In one preferred embodiment of the invention, the crystalline layer silicates corresponding to formula (I) are introduced into the tablets according to the invention solely through the builder additive used in accordance with the invention. The tablets advantageously contain the crystalline layer-form silicate corresponding to formula (I) in quantities of to at most 50% by weight, preferably in quantities of 5 to 45% by weight and more preferably in quantities of 10 to 40% by weight.
In the context of the present invention, a (co)polymeric polycar-boxylic acid is understood to be a non-neutralized or only partly neutralized homopolymer or copolymer. These include the homopolymers of acrylic or methacrylic acid and copolymers thereof with other ethylenically unsaturated monomers such as, for example, acrolein, dimethyl acrylic acid, ethyl acrylic acid, vinyl acetic acid, allyl acetic acid, malefic acid, fumaric acid, itaconic acid, meth(allylsulfonic acid), vinyl sulfonic acid, styrene sulfonic acid, acrylamidomethyl propane sulfonic acid and monomers containing phosphorus groups such as, for example, vinyl phosphonic acid, allyl phosphoric acid and acrylamidomethyl propane phosphonic acid and salts thereof, and hydroxyethyl (meth)acrylate sulfates, allyl alcohol sulfates and allyl alcohol phosphates. Polymers such as these are described, for example, in German patent applications DE-A-23 57 036, DE-A-44 39 978 and in European patent applications EP-A-0 075 820 and EP-A-0 451 508.
Preferred (co)polymers have an average molecular weight of 1000 to 100,000 glmole, preferably in the range from 2000 to 75,000 glmole and more preferably in the range from 2000 to 35,000 g/mole. The degree of neutralization of the acid groups is advantageously between 0 and 90%, preferably between 10 and 80% and more preferably between 30 and 70%.
Other suitable polymers are, above all, homopolymers of acrylic acid and copolymers of (meth)acrylic acid with malefic acid or malefic anhydride.
Other suitable copolymers are derived from terpolymers which can be obtained by polymerization of 10 to 70% by weight of monoethylenically unsaturated dicarboxylic acids containing 4 to 8 carbon atoms or salts thereof, 20 to 85% by weight of monoethylenically unsaturated monocar-boxylic acids containing 3 to 10 carbon atoms or salts thereof, 1 to 50% by weight of monounsaturated monomers, which release hydroxyl groups on the polymer chain after saponification, and 0 to 10% by weight of other radical-copolymerizable monomers. For the purposes of the use according to the invention, saponification of the monounsaturated monomers, which release a hydroxyl group on the polymer chain after saponification, is preferably carried out in a acidic medium. Products of the type mentioned above are described in German patent applications DE-A-43 00 772 and DE-A-195 16 957 and in WO-A-94115978.
Graft polymers of monosaccharides, oligosaccharides, polysaccha-rides and modified polysaccharides, as described in German patent applications DE-A-40 03 172 and DE-A-4415 623, are also suitable, as are the graft polymers with proteins of animal or vegetable origin disclosed in the European patent application, more particularly with modified proteins.
From the group of graft copolymers, copolymers of sugar and other polyhydroxy compounds and a monomer mixture with the following composition are preferably used: 45 to 96% by weight of monoethylenically unsaturated C3_~o monocarboxylic acid or mixtures of C3_1o monocarboxylic acids andlor salts thereof with polyvalent cations, 4 to 55% by weight of monomers containing monoethylenically unsaturated monosulfonic acid groups, monoethylenically unsaturated sulfuric acid esters, vinyl phosphonic acid and/or the salts of these acids with polyvalent cations and 0 to 30% by weight of water-soluble monoethylenically unsaturated com-pounds modified with 2 to 50 moles of alkylene oxide per mole of mono-ethylenically unsaturated compound. Such compounds are described in DE-A-42 21 381 and in DE-A-43 43 993.
Other suitable polymers are polyaspartic acids and derivatives thereof in non-neutralized or only partly neutralized form. The polyaspartic acids normally accumulate in the form of their alkali metal or ammonium salts. The non-neutralized or only partly neutralized products may be obtained therefrom by adding appropriate quantities of organic or inorganic acids and optionally removing the salts formed.
Products of the type in question may also be obtained by the thermal reaction of malefic acid and ammonia or by the condensation of aspartic acid and subsequent hydrolysis of the polysuccinimide formed. The production of products such as these is described, for example, in DE-A-36 26 672, DE-A-43 07 114, DE-A-44 27 287, EP-A-0 612 784, EP-A-0 644 257 and WO-A-92114753.
Graft polymers of acrylic acid, methacrylic acid, malefic acid and other ethylenically unsaturated monomers with the salts of polyaspartic acid normally accumulating in the above-described hydrolysis of the polysuccinimide are also particularly suitable. In their case, there is no need for the otherwise necessary addition of acid for the production of the only partly neutralized form of polyaspartic acid. The quantity of polyaspartate is normally selected so that the degree of neutralization of all the carboxyl groups incorporated in the polymer does not excess 80%, preferably 60%. Products of the type mentioned are described in detail in International patent application WO-A-94101486.
The quantities in which the non-neutralized or only partly neutralized (co)polymeric polycarboxylates are present in the compositions according to the invention are determined by the content of builder additives used in accordance with the invention and by their content of these polymers.
The builder additive used in accordance with the invention contains the crystalline layer silicate corresponding to formula (I) and the (co)poly meric polycarboxylic acid in a ratio by weight of preferably (40 to 1 ):1 and more preferably (20 to 2):1, ratios of 7:1 to about 3:1, based on the water free active substances, being particularly advantageous. The water content of the builder additives used in accordance with the invention is preferably between 4 and 20% by weight, the upper appropriate limit to the water content being made dependent on the fact that the builder additive should still be stable and free-flowing and should not form any lumps, even after storage at elevated temperatures of, for example, 40°C. It has been found that the lower limit to the water content influences the dissolving behavior of the builder additive. Accordingly, in the interests of a higher dissolving rate of the builder additive, additives containing 5 to 15% by weight of water are preferred, those containing 7 to 12% by weight of water being particularly preferred. The water content is determined over a period of 4 hours at a temperature of 140°C.
The builder additives used in accordance with the invention may be produced simply by contacting the crystalline layer silicate corresponding to formula (I) with an aqueous solution, preferably a concentrated aqueous solution, of the (co)polymeric polycarboxylic acid, optionally followed by drying to the requisite water content. Conventional mixers and granulators, such as the Lodige plowshare mixer or a Schugi mixer or an Eirich mixer or a Lodige CB 30 Recycler and other machines known to the expert, which above all enable a liquid to be sprayed onto a solid, are as suitable as fluidized bed mixers/granulators. The polymer solution acts as an agglo-meration aid. It is assumed that, in the reaction of the crystalline layer silicate corresponding to formula (I) with the acidic polymer, particularly where the polymer solution used has a pH value below 4, the sodium ions of the silicate are partly replaced by protons. However, the silicate skeleton with its layer structure and the majority of the sodium ions remain unchanged. The effect of this is that the builder additives used in accordance with the invention have only a slightly reduced starting alkalinity, but a far lower residual alkalinity than the pure crystalline layer silicate corresponding to formula (I). The residual alkalinity may be adjusted through the polymer acid content of the additives. Accordingly, the builder additive may be used as a buffer in the dishwasher detergents.
The builder additives may contain large quantities of (co)polymeric H 3957/H3957-I g carboxylic acid, preferably quantities of 2 to 40% by weight, more preferably quantities of 5 to 30% by weight and most preferably quantities of 10 to 25% by weight. The content of crystalline layer silicates of formula (I) in the builder additives is preferably between 50 and 90% by weight, more preferably between 60 and 90% by weight and most preferably between 65 and 85% by weight. The additives preferably have a calcium binding capacity above 185 mg CaCO~/g. The pH value of a 0.1 % by weight aqueous solution at 20°C is preferably above 10, but below 12.
The bulk density of the additives used in accordance with the invention varies according to the method used for their production and is normally above 400 to about 700 g/l. Whereas pure crystalline layer silicate corresponding to formula (I), such as SKS 6~, normally accumulates in very fine-particle form and also contains large amounts of dust, the builder additive used in accordance with the invention is a relatively coarse-particle powder or an agglomerate or granules which are finer when produced in a fluidized bed and coarser when produced, for example, in a high-speed mixer. Relative coarse-particle additives have a mean particle size (d5o), for example of about 450 to 900 Nm whereas relatively fine-particle additives have a mean particle size (d5o) of about 280 to 330 Nm. Even in the fine-particle additives, however, the percentage of dust is far lower than in the commercially available pure crystalline layer silicates corresponding to formula (I), more particularly SKS 6~.
The content of these builder additives in the tablets according to the invention is variable within wide limits and depends upon the function the tablets are expected for perform. Normal contents of these builder addi tives are between about 20 and 60% by weight, contents of 25 to 50% by weight being preferred and contents of up to 45% by weight being particu-larly preferred.
Disintegrators which, according to the invention, are not intended to be present in the tablets or in the tablet phases are regarded as auxiliaries which have a positive influence on the dissolving or disintegrating process in the aqueous phase used, but which otherwise have no effect as a builder in the tabletted detergent.
According to Rompp (9th Edition, Vol. 6, page 4440) and Voigt "Lehrbuch der pharmazeutischen Technologie" (6th Edition, 1987, pages 182-184), tablet disintegrators or disintegration accelerators are auxiliaries which promote the rapid disintegration of tablets in water or gastric juices and the release of the pharmaceuticals in an absorbable form. These substances, which are also known as "disintegrators" by virtue of their effect, are capable of undergoing an increase in volume on contact with water so that, on the one hand, their own volume is increased (swelling) and, on the other hand, a pressure can be generated through the release of gases which causes the tablet to disintegrate into relatively small particles.
Well-known disintegrators are, for example, carbonatelcitric acid systems, although other organic acids may also be used. Besides their disintegrating effect, however, these systems have a builder effect and, accordingly, definitely do not belong to the disintegrators which have no effect in the tabletted composition according to the invention, so that they may certainly be present in the tablets or tablet phases according to the invention. Preferred embodiments of the invention actually contain large amounts of organic carboxylic acids and carbonates. These preferred embodiments are water-softening tablets which are describe in detail hereinafter.
Swelling disintegration aids which are not intended to be present in accordance with the invention are, for example, synthetic polymers, such as polyvinyl pyrrolidone (PVP), or natural polymers and modified natural substances, such as cellulose and starch and derivatives thereof, alginates or casein derivatives.
In particular, no cellulose-based disintegrators should be present in the tablets or tablet phases according to the invention. Pure cellulose has the formal empirical composition (CsH~o05)~ and, formally, is a ~i-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 average molecular weights of 50,000 to 500,000.
According to the invention, cellulose derivatives obtainable from cellulose by polymer-analog reactions may also be used as cellulose-based disintegrators. These chemically modified celluloses include, for example, products of esterification or etherification reactions in which hydroxy hydrogen atoms have been substituted. However, celluloses in which the hydroxy groups have been replaced by functional groups that are not attached by an oxygen atom may also be used as cellulose derivatives.
The group of cellulose derivatives includes, for example, alkali metal celluloses, carboxymethyl cellulose (CMC), cellulose esters and ethers and aminocelluloses. Although compounds such as these certainly develop effects in the tabletted composition, particularly where it is a laundry detergent, they are preferably still not present in the tablets or tablet phases. Microcrystalline cellulose is mentioned as another cellulose-based disintegrator or as a constituent of that 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 micro-fine celluloses formed by hydrolysis provides the microcrystalline celluloses which have primary particle sizes of ca. 5 um and which can hp compacted, for example, to granules with a mean particle size of 200 Nm.
Tabletting aids which may be present in the tablets or tablet phases according to the invention in a quantity of up to at most 2% by weight are substances which provide for better cohesion of the individual powder-form or granular constituents and which therefore contribute towards the stability of the tablet.
In a preferred embodiment, the tablets or tablet phases contain only dust binding agents as tabletting aids. These include, in particular, short-chain polyethylene glycols with molecular weights below 800 g/mole and paraffins, more particularly paraffin oils.
The unwanted tabletting aids include, in particular, polyethylene glycols with molecular weights of 1000 to 10,000 glmole, starch, cellulose, starch and cellulose derivatives and also gelatin and polyvinyl pyrrolidone.
Some detergent ingredients, such as certain liquid or paste-form nonionic surfactants, also act as tabletting aids. Although they may be present in tablets according to the invention where the tablets are intended to act as laundry detergents, they are not necessary as tabletting aids. Accordingly, preferred embodiments of the invention are also free from such nonionic surfactants.
Tablets or tablet phases containing these ingredients may be tabletted under moderate pressures and still show high edge abrasion resistance. At the same time, the tablets are readily soluble, their solubility being at least comparable with that of tablets known from the prior art which can contain both relatively large quantities of tabletting aids and also the disintegrators described above. In contrast to such tablets, the tablets or tablet phases according to the invention can accommodate a very high active substance content because they do not contain these disintegrators at all and the described tabletting aids in only very small quantities.
Besides the constituents already described, the tablets may contain other ingredients, preferably substances which have (co)builder properties.
Thus, the tablets may also contain the builders, crystalline sodium layer silicates and polymeric polycarboxylic acids already mentioned in addition to the additive, even in separate form. This may be the case above all when the tablets contain several "phases" or "layers" which have a homogeneous composition in themselves. In the case of multiphase tablets of the type in question, it can be preferred for the various phases which can contain various active substances to dissolve at different rates.
Accordingly, it may be preferred to use the additive in only one phase according to the invention whPrPa~ fihEa n+hcr nh~~o ...,.,+.,~.,~ ....
disintegrator or another disintegrator. However, it may also be entirely desirable for the other phases) to contain the same builders, but in a form which does not have the disintegrating effect of the additive.
The tablets according to the invention may also contain other builders and co-builders.
Other builders are, primarily, alumosilicates and phosphates. The alumosilicate is preferably a finely crystalline, synthetic zeolite containing bound water, more particularly zeolite A, X andlor zeolite P. Zeolite MAP~
(Crosfield), for example, is used as a P-type zeolite. However, zeolite Y
and mixtures of A, X, Y andlor P are also suitable. One such mixture of zeolite X and zeolite A is marketed by Condea Augusta S.p.A. under the name of Vegobond AX~. The zeolite may be used as a spray-dried powder or even as an undried stabilized 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 C,2_~$ fatty alcohols containing 2 to 5 ethylene oxide groups, C~2_~4 fatty alcohols containing 4 to 5 ethylene oxide groups or ethoxylated isotridecanols. Suitable zeolites have a mean particle size of less than 10 ~.m (volume distribution, as measured by the Coulter Counter Method) and contain preferably 18 to 22% by weight and more preferably 20 to 22% by weight of bound water.
Other possible builders are amorphous sodium silicates with a modulus (NaZO: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 rnay 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 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. Their content is generally not more than 25% by weight and preferably not more than 20%
by weight, based on the final composition. In some cases, it has been found that tripolyphosphates in particular, even in small quantities of up to at most 10% by weight, based on the final composition, lead to a synergisic improvement in multiple wash cycle performance in combination with other builders. It can also be of advantage in this regard to use phosphate in the form of the phosphate compounds described in earlier German patent application DE 198 59 807.6.

Besides the polymeric polycarboxylic acids used in accordance with the invention, useful organic builders are, for example, the polycarboxylic acids usable, for example, in the form of their sodium salts (polycarboxylic acids in this context being understood to be carboxylic acids carrying more than one acid function). Examples include citric acid, adipic acid, succinic acid, glutaric acid, malic acid, tartaric acid, malefic acid, fumaric acid, sugar acids, aminocarboxylic acids, nitrilotriacetic acid (NTA), providing its use is not ecologically unsafe, and mixtures thereof. Preferred salts are the salts of the polycarboxylic acids, such as citric acid, adipic acid, succinic acid, glutaric acid, tartaric acid, sugar acids and mixtures thereof. The acids per se may also be used. Besides their builder effect, the acids typically have the property of an acidifying component and, accordingly, are also used to establish a lower and more mild pH value in laundry or dishwashing detergents. Citric acid, succinic acid, glutaric acid, adipic acid, gluconic acid and mixtures thereof are particularly mentioned in this regard.
Other suitable builders are polyacetals which may be obtained by reaction of dialdehydes with polyol carboxylic acids containing 5 to 7 carbon atoms and at least three hydroxyl groups, for example as described in European patent application EP-A-0 280 223. Preferred polyacetals are obtained from dialdehydes, such as glyoxal, glutaraldehyde, terephthal-aldehyde and mixtures thereof and from polyol carboxylic acids, such as gluconic acid and/or glucoheptonic acid.
Other suitable co-builders are oxydisuccinates and other derivatives of disuccinates, preferably ethylenediamine disuccinate. Ethylenediamine N,N'-disuccinate (EDDS), of which the synthesis is described for example in US 3,158,615, is preferably used in the form of its sodium or magnesium salts. The glycerol disuccinates and glycerol trisuccinates described, for example, in US 4,524,009, US 4,639,325, in European patent application EP-A-0 150 930 and in Japanese patent application JP 931339896 are also preferred in this connection. The quantities used in zeolite-containing and/or silicate-containing formulations are from 3 to 15% by weight.
Other useful organic co-builders are, for example, acetylated hydroxycarboxylic acids and salts thereof which may optionally be present in lactone form and which contain at least 4 carbon atoms, at least one hydroxy group and at most two acid groups. Co-builders such as these are described, for example, in International patent application WO-A-95120029.
Another class of substances with co-builder properties are the phosphonates, more particularly hydroxyalkane and aminoalkane phos phonates. Among the hydroxyalkane phosphonates, 1-hydroxyethane-1,1 diphosphonate (HEDP) is particularly important as a co-builder. It is preferably used in the form of a sodium salt, the disodium salt showing a neutral reaction and the tetrasodium salt an alkaline ration (pH 9).
Preferred aminoalkane phosphonates are ethylenediamine tetramethylene phosphonate (EDTMP), diethylenetriamine pentamethylene phosphonate (DTPMP) and higher homologs thereof. They are preferably used in the form of the neutrally reacting sodium salts, for example as the hexasodium salt of EDTMP and as the hepta- and octasodium salt of DTPMP. Within the class of phosphonates, HEDP is preferably used as builder. The aminoalkane phosphonates also show a pronounced heavy metal binding capacity. Accordingly, it can be of advantage, particularly where the detergents also contain bleaching agents, to use aminoalkane phosphonates, more especially DTPMP, or mixtures of the phosphonates mentioned.
In addition, any compounds capable of forming complexes with alkaline earth metal ions may be used as co-builders.
In one preferred embodiment of the invention, the tablets are water softening tablets. Water softening tablets have a very high percentage content of builders. 60 to 100% by weight of preferred water softening tablets and, in particularly advantageous embodiments, even as much as 80% by weight consist of builders and co-builders. Although active substance contents of more than 90% by weight and, in particular, more than 95% by weight are also preferred in these builder tablets, they are difficult to achieve because water is also introduced into the tablets by the individual ingredients.
Water softening tablets containing the carbonatelpolycarboxylic acid system described in the foregoing are particularly preferred. Water softening systems such as these react effervescently with one another on contact with water and thus contribute towards the disintegration of the tablets, soften the water and, in addition, dissolve completely. The carbonate used may be any alkali metal carbonate, bicarbonate or sesqui-carbonate either on its own or in the form of mixtures with others.
However, it is particularly preferred to use bicarbonates and sesquicarbon-ates. Polycarboxylic acids in this context are understood to be carboxylic acids which carry more than one acid function. Examples of such carboxylic acids are citric acid, adipic acid, succinic acid, glutaric acid, malic acid, tartaric acid, malefic acid, fumaric acid, sugar acids, aminocar-boxylic acids, nitrilotriacetic acid (NTA), providing there are no ecological objections to its use, and mixtures thereof. Citric acid, succinic acid, glutaric acid, adipic acid, gluconic acid and mixtures thereof are particularly preferred. These acids may also be used completely or partly in the form of their salts. Preferred water softening tablets contain 10 to 40% by weight and more particularly 15 to 30% by weight of such polycarboxylic acids or polycarboxylic acid salts and 10 to 50% by weight and, more particularly, 20 to 45% by weight of alkali metal carbonate, bicarbonate or sesquicarbonate.
In another embodiment of the invention, the tablets are laundry detergent tablets.
Laundry detergent tablets may advantageously contain surfactants.
These surfactants belong to the group of anionic, nonionic, zwitterionic and cationic surfactants, anionic surfactants being clearly preferred for economic reasons and for their performance spectrum.
Suitable anionic surfactants are, for example, those of the sulfonate and sulfate type. Preferred surfactants of the sulfonate type are, for example, C9_~3 alkyl benzenesulfonates, olefin sulfonates, i.e. mixtures of alkene and hydroxyalkane sulfonates, and the disulfonates obtained, for example, from C~2_~8 monoolefins with an internal or terminal double bond by sulfonation with gaseous sulfur 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,z_~$ 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 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 coconut alcohol, tallow alcohol, lauryl, myristyl, cetyl or stearyl alcohol, or C~o_2o oxoalcohols and the corresponding semiesters of secondary alcohols with the same chain length. Other preferred alk(en)yl sulfates are those with the chain length mentioned which contain a synthetic, linear alkyl chain based on a petrochemical and which are similar in their degradation behavior to the corresponding compounds based on oleochemical raw materials. C~2_~s alkyl sulfates and C~2.~5 alkyl sulfates and also C~4_~5 alkyl sulfates are particularly preferred from the washing performance point of view. 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_,e fatty alcohols containing 1 to 4 EO, are also suitable.
Other suitable anionic surfactants are the salts of alkyl sulfosuccinic acid which are also known as sulfosuccinates or as sulfosuccinic acid esters and which represent monoesters and/or diesters of sulfosuccinic acid with alcohols, preferably fatty alcohols and, more particularly, ethoxylated fatty alcohols. Preferred sulfosuccinates contain Cg_18 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 H 39571H3957-I 1 g 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.
So far as the choice of anionic surfactants is concerned, there are no basic requirements to restrict the freedom of formulation. Anionic surfactants preferably used in detergents are the alkyl benzenesulfonates and fatty alcohol sulfates, preferred detergent tablets containing 2 to 20%
by weight, preferably 2.5 to 15% by weight and more preferably 5 to 10%
by weight fatty alcohol sulfate(s), based on the weight of the detergent tablets.
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 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, C~2_~$ 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,Z_~8 alcohol containing 5 EO. The degrees of ethoxylation mentioned represent statistical mean values which, for a special product, can be a whole number or a broken number. Preferred alcohol 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 alcohol containing 14 EO, 25 EO, 30 EO or 40 ' CA 02302141 2000-03-27 EO.
Another class of preferred nonionic surfactants which may be used either as sole nonionic surfactant or in combination with other nonionic surfactants are alkoxylated, preferably ethoxylated or ethoxylated and propoxylated, fatty acid alkyl esters preferably containing 1 to 4 carbon atoms in the alkyl chain, more especially the fatty acid methyl esters which are described, for example, in Japanese patent application JP 58!217598 or which are preferably produced by the process described in International patent application WO-A-90113533.
Another class of nonionic surfactants which may advantageously be used are the alkyl polyglycosides (APGs). Suitable alkyl polyglycosides correspond to the general formula RO(G)Z where R is a linear or branched, more particularly 2-methyl-branched, saturated or unsaturated 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 glycosidation z is between 1.0 and 4.0, preferably between 1.0 and 2.0 and more preferably between 1.1 and 1.4.
Linear alkyl polyglucosides, i.e. alkyl polyglycosides in which the polyglycosyl component is a glucose unit and the alkyl component is an n alkyl group, are preferably used.
The tablets may advantageously contain alkyl polyglycosides, APG
contents of more than 0.2% by weight, based on the tablet as a whole, being preferred. Particularly preferred detergent tablets contain APGs in quantities of 0.2 to 10% by weight, preferably in quantities of 0.2 to 5% by weight and more preferably in quantities of 0.5 to 3% by weight.
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 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-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 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 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, fructose, maltose, lactose, galactose, mannose or i ' CA 02302141 2000-03-27 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.
The surfactant content of detergent tablets is normally between 10 and 40% by weight, preferably between 12.5 and 30% by weight and more preferably between 15 and 25% by weight. Bleach tablets and water softening tablets are normally free free from surfactants.
Besides the builder constituents and surfactants mentioned, the tablets according to the invention may also contain one or more substances from the groups of bleaching agents, bleach activators, enzymes, pH
regulators, perfumes, perfume carriers, fluorescers, dyes, foam inhibitors, silicone oils, redeposition inhibitors, optical brighteners, discoloration ihibitors and dye transfer inhibitors. These substances are described in the following.
Among the compounds yielding H202 in water which serve as bleaching agents, sodium perborate tetrahydrate, sodium perborate monohydrate and sodium carbonate are particularly important. Other useful bleaching agents are, for example, peroxypyrophosphates, citrate perhydrates and H202-yielding peracidic salts or peracids, such as perbenzoates, peroxophthalates, diperazelaic acid, phthaloiminoperacid or diperdodecane dioic acid. Even where the bleaching agents are used, there is no need for surfactants andlor builders so that pure bleach tablets can be produced. If pure bleach tablets are to be used in the washing of laundry, a combination of sodium percarbonate and sodium sesqui-carbonate is preferred irrespective of the other ingredients present in the tablets. In principle, bleaching agents from the group of organic bleaches may also be used. Typical organic bleaching agents are diacyl peroxides, such as dibenzoyl peroxide for example. Other typical organic bleaching ' CA 02302141 2000-03-27 agents are the peroxy acids, of which alkyl peroxy acids and aryl peroxy acids are particularly mentioned as examples. Preferred representatives are (a) peroxybenzoic acid and ring-substituted derivatives thereof, such as alkyl peroxybenzoic acids, but also peroxy-a-naphthoic acid and magnesium monoperphthalate, (b) aliphatic or substituted aliphatic peroxy acids, such as peroxylauric acid, peroxystearic acid, s-phthalimidoperoxycaproic acid [phthaloiminoperoxyhexanoic acid (PAP)], o-carboxybenzamidoperoxycaproic acid, N-nonenylamidoperadipic acid and N-nonenylamidopersuccinates, and (c) aliphatic and araliphatic peroxydicarboxylic acids, such as 1,12-diperoxycarboxylic acid, 1,9-diperoxyazelaic acid, diperoxysebacic acid, diperoxybrassylic acid, diperoxyphthalic acids, 2-decyldiperoxybutane-1,4-dioic acid, N,N-terephthaloyl-di(6-aminopercaproic acid).
In order to obtain an improved bleaching effect where washing is carried out at temperatures of 60°C or lower, bleach activators may be incorporated in the tablets according to the invention. 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 andlor optionally substituted perbenzoic acid under perhydrolysis conditions. Substances bearing O- and/or N-acyl groups with the number of carbon atoms mentioned and/or optionally substituted benzoyl groups are suitable. Preferred bleach activators are polyacylated alkylenediamines, more particularly tetraacetyl ethylenediamine (TAED), acylated triazine derivatives, more particularly 1,5-diacetyl-2,4-dioxohexa-hydro-1,3,5-triazine (DADHT), acylated glycolurils, more particularly tetra-acetyl 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 or mixtures thereof. Enzymes obtained from bacterial strains or fungi, such as Bacillus subtilis, Bacillus licheniformis and Streptomyces griseus, are particularly suitable. Proteases of the subtilisin type are preferred, proteases obtained from Bacillus lentus being particularly preferred. Enzyme mixtures, for example of protease and amylase or protease and lipase or protease and cellulase or of cellulase and lipase or of protease, amylase and lipase or of protease, lipase and cellulase, but especially cellulase-containing mixtures, are of particular interest. Peroxidases or oxidases have also proved to be suitable in some cases. The enzymes may be adsorbed to supports and/or encapsulated in shell-forming substances to protect them against premature decomposition.
The percentage content of the enzymes, enzyme mixtures or enzyme granules in the tablets according to the invention may be, for example, from about 0.1 to 5% by weight and is preferably from 0.1 to about 2% by weight. The most commonly used enzymes include lipases, amylases, cellulases and proteases. Preferred proteases are, for example, BLAP~140 (Biozym), Optimase~ M-400 and Opticlean~ M-250 (Solvay Enzymes); Maxacal~ CX and Maxapem~ or Esperase~ (Gist Brocades) or even Savinase~ (Novo). Particularly suitable cellulases and lipases are Celluzym~ 0, T and Lipolase~ 30 T (Novo Nordisk). The amylases particularly used are Duramyl~ and Termamyl~ 60 T and Termamyl~ 90 T
(novo), Amylase-LT~ (Solvay Enzymes) abd Maxamyl~ P5000 (Gist Brocades). Other enzymes may also be used.
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)-Biphenyl, may also be present. Mixtures of the brighteners mentioned above may also be used.
Dyes and perfumes 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 perfumes include individual perfume compounds, for example synthetic products of the ester, ether, aldehyde, ketone, alcohol and hydrocarbon type. Perfume compounds of the ester type are, for example, benzyl acetate, phenoxyethyl isobutyrate, p-tert.butyl cyclohexyl acetate, linalyl acetate, dimethyl benzyl carbinyl acetate, phenyl ethyl acetate, linalyl benzoate, benzyl formate, ethyl methyl phenyl glycinate, allyl cyclohexyl propionate, styrallyl propionate and benzyl salicylate. The ethers include, for example, benzyl ethyl ether; the aldehydes include, for example, the linear alkanals containing 8 to 18 carbon atoms, citral, citronellal, 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 perfumes which together produce an attractive perfume note are preferably used. Perfume oils such as these may also contain natural perfume mixtures obtainable from vegetable sources, for example pine, citrus, jasmine, patchouli, rose or ylang-ylang oil. Also suitable are clary oil, camomile oil, clove oil, melissa oil, mint oil, cinnamon leaf oil, lime blossom oil, juniper berry oil, vetiver oil, olibanum oil, galbanum oil and labdanum oil and orange blossom oil, neroli oil, orange peel oil and sandalwood oil.
The detergent tablets according to the invention normally contain less than 0.01 % by weight of dyes whereas perfumes/fragrances can make up as much as 2% by weight of the formulation as a whole.
The perfumes may be directly incorporated in the detergents according to the invention, although it can also be of advantage to apply the perfumes to supports which strengthen the adherence of the perfume to the washing and which provide the textiles with a long-lasting fragrance through a slower release of the perfume. Suitable support materials are, for example, cyclodextrins, the cyclodextrinlperfume complexes optionally being coated with other auxiliaries.
In order to improve their aesthetic impression, the detergents 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.
The present invention also relates to a process for the production of tablets containing builders and optionally other ingredients of detergents or phases of such tablets, characterized in that a powder-form or granular additive containing a crystalline layer silicate corresponding to general formula (I):
NaMSix02x+~ ~ yH24 (I) in which M is sodium or hydrogen, x is a number of 1.9 to 2.2 and y is a number of 0 to 33, and (co)polymeric polycarboxylic . acid as its key constituents is mixed with other builders and optionally ingredients of detergents to form a premix and the resulting premix is tabletted without the incorporation of additional disintegrators without a builder effect and with at most 2% by weight of tabletting aids to form tablets or phases of tablets.
The builder additive is the additive described in the foregoing. Since the production process described here is intended to provide the tablets or phases of tablets described in the foregoing, it is self evident that the preferred embodiments described in reference to the tablets are also preferably produced accordingly in the process.
As mentioned in the foregoing, the tablets according to the invention contain the builder additives according to the invention in varying amounts according to the application envisaged. In complete analogy, processes according to the invention in which the builder additive is used in quantities of 20 to 60% by weight, preferably in quantities of 25 to 55% by weight and more preferably in quantities of up to 45% by weight are also preferred.
Even the premixes containing the described builder additive have advantages. These premixes show very good flow properties, so that the filling shoe can be uniformly filled, and hence help in guaranteeing a uniform tablet quality. In addition, the premix does not form lumps and, accordingly, does not cake on the walls of the tablet press. In addition, the builder additive according to the invention enables the premix to be tabletted at moderate pressures. This preserves the tabletting tools and H 39571H3957-I 2g thus increases their useful life.
Depending on the application envisaged, the builder additive is mixed with other detergent ingredients and the resulting premix is tabletted.
Preferred processes according to the invention are characterized in that the builder additive is mixed with at least one oxygen bleaching agent selected from the group of alkali metal perborates, alkali metal percarbonates, organic peracids and hydrogen peroxide. The bleaching agents in question were described in the foregoing.
The bleaching performance of bleach-containing tablets, such as water softening tablets, laundry detergent tablets and bleach tablets, is preferably boosted by the use of bleach activators. Thus, preferred processes according to the invention are characterized in that the builder additive is mixed with at least one bleach activator, preferably from the group of polyacylated alkylenediamines, more particularly tetraacetyl ethylenediamine (TAED), N-acyl imides, more particularly N-nonanoyl succinimide (NOSI), acylated phenol sulfonates, more particularly n-nonanoyl or isononanoyloxybenzenesulfonate (n- or iso-NOBS), n-methyl morpholinium acetonitrile methyl sulfate (MMA) and/or the bleach-boosting transition metal complexes, more particularly containing the central atoms Mn, Fe, Co, Cu, Mo, V, Ti andlor Ru, preferably from the group of manganese andlor cobalt salts and/or complexes, more preferably the cobalt (ammine) complexes, cobalt (acetate) complexes, cobalt (carbonyl) complexes, chlorides of cobalt or manganese andlor manganese sulfate.
As mentioned in the foregoing, the tablets or phases of tablets according to the invention may contain other ingredients of detergents so that preferred variants of the process are carried out accordingly.
In one particularly preferred embodiment, the premix additionally contains one or more substances from the group of enzymes, pH
regulators, perfumes, perfume carriers, fluorescers, dyes, foam inhibitors, silicone oils, redeposition inhibitors, optical brighteners, discoloration r H 3957IH3957-I 2g inhibitors and dye transfer inhibitors.
Before the particulate premix is compressed to form 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 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 compound is preferably "powdered" with fine-particle zeolite, zeolites of the faujasite type being preferred. In the context of the present invention, the expression "zeolite of the faujasite type" encompasses all three zeolites which form the faujasite subgroup of zeolite structural group 4 (cf. Donald W. Breck: "Zeolite Molecular Sieves", John Wiley & Sons, New York, London, Sydney, Toronto, 1974, page 92). Besides zeolite X, therefore, zeolite Y and faujasite and mixtures of these compounds may also be used, pure zeolite X being preferred. Mixtures of the co-crystallizates of zeolites of the faujasite type with other zeolites which do not necessarily have to belong to zeolite structure group 4 may also be used for powdering, at least 50% by weight of the powdering material advantageously consisting of a zeolite of the faujasite type.
The tablets according to the invention are produced by first dry-mixing the ingredients, which may be completely or partly pregranulated, and then tabletting the resulting premix using conventional processes. To produce the tablets according to the invention, the premix is compacted between two punches in a die to form a solid compactate. This process, which is referred to in short hereinafter as tabletting, comprises four phases, namely metering, compacting (elastic deformation), plastic deformation and ejection.
The premix is first introduced into the die, the filling level and hence the weight and shape of the tablet formed being determined by the position of the lower punch and the shape of the die. Uniform dosing/metering, i s even at high tablet throughputs, is preferably achieved by volumetric metering of the premix. As the tabletting process continues, the top punch comes into contact with the premix and continues descending towards the bottom punch. During this compaction phase, the particles of the premix are pressed closer together, the void volume in the filling between the punches continuously diminishing. The plastic deformation phase in which the particles coalesce and form 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 volumes, it is preferred to use eccentric tablet presses in which the punches) islare 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 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, 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 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 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 (BEILU). 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, 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 w CA 02302141 2000-03-27 compartment of commercially available domestic washing machines, so that the tablets can be introduced directly, i.e. without a dosing aid, into the dispensing compartment where they dissolve on contact with water.
However, it is of course readily possible - and preferred in accordance with the present invention - to use the water softening and laundry detergent tablets in conjunction with a dosing aid.
Another preferred tablet which can be produced has a plate-like or slab-like structure with alternately thick long segments and thin short segments, so that individual segments can be broken off from this "bar" at the predetermined weak spots, which the short thin segments represent, and introduced into the machine. This "bar" principle can also be embodied in other geometric forms, for example vertical triangles which are only joined to one another at one of their longitudinal sides.
In another possible embodiment, however, the various components are not compressed to form a single tablet, instead the tablets obtained comprise several layers or "phases", i.e. at least two layers. These various layers may have different dissolving rates. This may advantageously be achieved in particular if only one of the layers contains the builder additive acording to the invention while the other layer contains no disintegrator at all or another disintegrator. This can provide the tablets with favorable performance properties. If, for example, the tablets contain components which adversely affect one another, one component may be integrated in the more quickly dissolving layer while the other component may be incorporated in a more slowly dissolving layer so that the first component can already have reacted off by the time the second component dissolves.
The various layers of the tablets can be arranged in the form of a stack, in which case the inner layers) dissolve at the edges of the tablet before the outer layers have completely dissolved. Alternatively, however, the inner layers) may also be completely surrounded by the layers lying further to the outside which prevents constituents of the inner layers) from dissolving prematurely.
In another 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 bleach-ing agent and any bleach activators present and/or enzymes may be spatially separated from one another in one and the same tablet. Multilayer 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 effects 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 be determined in accordance with the following equation:

a =
nDt where n 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 Water softening tablets were produced from the ingredients listed in Table 1 in a rotary press (manufacturer: Fette). To this end, the individual components were mixed and the resulting premix was tabletted under the pressure shown in Table 2. All the tablets had a weight of 18 g. The tabletting pressure was selected so that all the tablets had the same height.
A layer silicate/polymer compound was used in Examples E1 to E3 according to the invention. This compound had been formed by reacting SKS-6~ (Clariant) with a terpolymer according to patent application EP-A-849 355. The terpolymer used had been produced in accordance with the disclosure of WO 94!15978 from 80% by weight of acrylic acid and malefic acid in a ratio by weight of 7:3 and 20% by weight of vinyl acetate and then saponified in an acidic medium (commercial product of Stockhausen). The resulting builder additive contained 71 % by weight of SKS-6, 20% by weight of the terpolymer and 9% by weight of water. Copolymer - an acrylic acid/maleic acid copolymer (Sokalan CP5~, a product of BASF) -was used in Example E2 and in the Comparison Examples. Comparison Examples C1 and C3 contained layer silicate in the form of SKS-6 powder.
The Comparison Examples also contained microcrystalline cellulose as a disintegrator and a polyethylene glycol with a molecular weight of 4000 g/mole as a tabletting aid. In exactly the same way as the polyethylene glycol used in the Comparison Examples (molecular weight 400 glmole), the paraffin oil used in the Examples according to the invention serves as a dust binding agent. Balances to 100% by weight in Table 1 are made up by water additionally present and salts.
The Examples according to the invention gave harder tablets with greater edge breakage stability than the Comparison Examples, despite lower tabletting pressures. At the same time, the tablets according to the invention have comparable dissolving times to the Comparison Examples.
Less caking on the walls of the filling shoes and in the die were also observed in the production of the tablets according to the invention (see Table 2).
Table 1:
Composition of the tablets [% by weight]

Citric acid 21 26 28 21 16 14 Bicarbonate 30 34 42 30 25 20 Citrate - - - - - 35 Sodium perborate monohydrate4 - _ _ _ _ Paraffin oil 1 1 1 - - _ Microcrystalline cellulose - - - 6 7 7 Zeolite - - - - 30 -Copolymer - 5 - 9 8 14 Layer silicate (powder) - _ _ 3p _ 5 Layer silicate/polymer compound44 34 29 - - _ The hardness of the tablets was measured by deforming a tablet until it broke, the force being applied to the sides of the tablet and the maximum force withstood by the tablet being determined. The measure-ment was carried out in a Holland CT5 hardness tester with punch diameters of 8 mm.
The edge breakage test was carried out in a rectangular plastic container with edge lengths of 18 x 14 x 22 cm. Five tablets were weighed into this container which was then rotated for 1 minute at 40 r.p.m. The tablets were then reweighed, the result being expressed as the weight of the tablets after the test as a percentage of the weight of the tablets before the test (Table 2).

The dissolving test was carried out in a glass beaker at 20°C. To this end, a 14.8 x 34.4 mm tablet was placed on a sieve with a mesh width of 0.6 x 0.6 cm, after which the sieve was suspended in a 1000 ml glass beaker filled with water. The time which the tablet took to drop through the sieve was measured while stirring.
For the dissolving test in a washing machine, three tablets were placed in the drum of a washing machine filled with laundry. The machine was then switched on (30°C program, no prewash). The time measure-ment was started when the drum began to rotate. The washing process was then terminated and the water pumped off after 1, 2, 3, 4 and 5 minutes. The time after which no tablet residues were found was then determined as the dissolving time. The values listed in Table 2 are mean values of double determinations.
Caking on the tablet press was visually evaluated. Evaluation is based on the following code: very good (++); no significant caking; good (+): visible caking, but no adverse effect on tabletting; satisfactory (0):
visible caking, slight interference with tabletting; poor (-): serious interfer-ence with tabletting.
The experimental data of the individual tablet series are shown in Table 2:

H 39571H3957-I 3g Table 2:
Properties of the tablets Tabletting pressure (kN] 32 ~ 46 56 70 _ 74 Tablet hardness (kg] 12 ~ 11 12 9 8 6 Edge breakage test (%] 94 92 91 84 86 82 Dissolving time (mina.]

- in a glass beaker 1.3 1.0 0.8 0.8 2.5 0.7 - in a washing machine 1.5 1.5 1.5 1.5 3.5 1.5 Bulk density (gll] 810 810 810 770 680 740 Caking ++ ++ ++ + - +

Claims (16)

1. A tablet containing builders and optionally other ingredients of detergents or a phase of such a tablet, characterized in that it contains a powder-form or granular additive which contains a crystalline layer silicate corresponding to general formula (I):
NaMSi x O2x+1 ~ yH2O (I) in which M is sodium or hydrogen, x is a number of 1.9 to 2.2 and y is a number of 0 to 33, and (co)polymeric polycarboxylic acid as key ingredients, the tablet containing no additional disintegrator without a builder effect and at most

2% by weight of additional tabletting aid.
2. A tablet or tablet phase as claimed in claim 1, characterized in that it contains the crystalline layer silicate corresponding to formula (I) in quantities of 2 to at most 50% by weight, preferably in quantities of 5 to 45% by weight and more preferably in quantities of 10 to 40% by weight.

3. A tablet or tablet phase as claimed in claim 1 or 2, characterized in that it contains the builder additive in quantities of 20 to 60% by weight, preferably in quantities of 25 to 55% by weight and more preferably in quantities of up to 45% by weight.

4. A tablet or tablet phase as claimed in any of claims 1 to 3, characterized in that it contains a builder additive containing 50 to 90% by weight, preferably 60 to 90% by weight and more preferably 65 to 85% by weight of crystalline layer silicate corresponding to formula (I), 2 to 40% by weight, preferably 5 to 30% by weight and more preferably 10 to 25% by weight of polymeric polycarboxylic acid and 4 to 20% by weight, preferably 5 to 15%
by weight and more preferably 7 to 12% by weight of water.

5. A tablet or tablet phase as claimed in any of claims 1 to 4, characterized in that the (co)polymeric polycarboxylic acid in the builder additive has a molecular weight of 1000 to 100,000 g/mole, preferably 2000 to 75,000 g/mole and more preferably 2000 to 35,000 g/mole, the degree of neutralization of the acid groups being between 0 and 90%, preferably between 10 and 80% and more preferably between 30 and 70%.

6. A tablet or tablet phase as claimed in any of claims 1 to 5, characterized in that the tablet does not contain any disintegrators based on polyvinyl pyrrolidone or natural polymers or modified natural materials, such as cellulose and starch or starch derivatives, such as alginates or casein derivatives, above all no microcrystalline cellulose, and only dust binding agents, more particularly short-chain polyethylene glycols with molecular weights below 800 g/mole or paraffins, as tabletting aids.

7. A tablet or tablet phase as claimed in any of claims 1 to 6, characterized in that the tablet is a water-softening tablet which preferably contains 60 to 100% by weight of builders and, more preferably, more than 80% by weight of builders.

8. A tablet or tablet phase as claimed in claim 7, characterized in that the tablet contains 10 to 40% by weight, more particularly 15 to 30% by weight of polycarboxylic acids or polycarboxylic acid salts and 10 to 50% by weight and more particularly 20 to 45% by weight of alkali metal carbonate, bicarbonate or sesquicarbonate.

9. A tablet or tablet phase as claimed in any of claims 1 to 6, characterized in that the tablet is a laundry detergent tablet.

10. A tablet or tablet phase as claimed in claim 9, characterized in that the tablet contains alkyl benzenesulfonate and 2 to 20% by weight, preferably 2.5 to 15% by weight and more preferably 5 to 10% by weight of fatty alcohol sulfate.

11. A tablet or tablet phase as claimed in any of claims 1 to 10, characterized in that it additionally contains one or more substances from the groups of bleaching agents, bleach activators, enzymes, pH regulators, perfumes, perfume carriers, fluorescers, dyes, foam inhibitors, silicone oils, redeposition inhibitors, optical brighteners, discoloration inhibitors and dye transfer inhibitors.

12. A process for the production of tablets containing builders and optionally other ingredients of detergents or phases of such tablets, characterized in that a powder-form or granular additive containing a crystalline layer silicate corresponding to general formula (I):
NaMSi x O2x+1 ~ yH2O (I) in which M is sodium or hydrogen, x is a number of 1.9 to 2.2 and y is a number of 0 to 33, and (co)polymeric polycarboxylic acid as its key constituents is mixed with other builders and optionally ingredients of detergents to form a premix and the resulting premix is tabletted without the incorporation of additional disintegrators without a builder effect and with at most 2% by weight of tabletting aids to form tablets or phases of tablets.

13. A process as claimed in claim 12, characterized in that the builder additive is used in quantities of 20 to 60% by weight, preferably in quantities of 25 to 55% by weight and more preferably in quantities of up to 45% by weight.

14. A process as claimed in claim 13 or 14, characterized in that the builder additive used contains 50 to 90% by weight, preferably 60 to 90%
by weight and more preferably 65 to 85% by weight of crystalline layer silicate corresponding to formula (I), 2 to 40% by weight, preferably 5 to 30% by weight and more preferably 10 to 25% by weight of (co)polymeric polycarboxylic acid and 4 to 20% by weight, preferably 5 to 15% by weight and more preferably 7 to 12% by weight of water, the (co)polymeric polycarboxylic acid having a molecular weight of 1000 to 100,000 g/mole, preferably 2000 to 75,000 g/mole and more preferably 2000 to 35,000 g/mole and the degree of neutralization of the acid groups being between 0 and 90%, preferably between 10 and 80% and more preferably between 30 and 70%.

15. A process as claimed in claim 13 or 14, characterized in that the premix additionally contains one or more substances from the group of enzymes, pH regulators, perfumes, perfume carriers, fluorescers, dyes, foam inhibitors, silicone oils, redeposition inhibitors, optical brighteners, discoloration inhibitors and dye transfer inhibitors.

16. The use of a powder-form or granular additive containing a crystalline layer silicate corresponding to general formula (I):
NaMSi x O2x+1 ~ yH2O (I) in which M is sodium or hydrogen, x is a number of 1.9 to 2.2 and y is a number of 0 to 33, and (co)polymeric polycarboxylic acid as its key constituents as a tabletting aid and disintegrator in tablets or individual tablet phases.