CA2300018A1 - Interengaging detergent tablets - Google Patents

Abstract

Tablets with one or more elevations and/or depressions on or in their upper surface and one or more depressions and/or elevations in or on their underneath planoparallel to their upper surface, which are designed to interengage, have handling and dosage advantages.

Description

INTERENGAGING DETERGENT TABLETS
Field of the Invention This invention relates generally to compact shaped bodies having detersive properties. Detersive shaped bodies include, for example, laundry detergent tablets, tablets for dishwashing machines or for cleaning hard surfaces, bleach tablets for use in washing or dishwashing machines, water softening tablets or stain remover tablets. More particularly, the present invention relates to detergent tablets which are used for cleaning tableware in a domestic dishwashing machine and which are referred to in short as dishwasher tablets.
Background of the Invention Detergent tablets are widely described in the prior art and have firmly established themselves alongside the traditional powder-form products as a supply form for detergents, particularly in the dishwashing detergent sector. One of the advantages of tablets - their simple dosability - is regarded by many consumers to be a disadvantage because tablets with their defined quantities of ingredients remove dosage control from the hands of the consumer. In the pharmaceutical sector, the problem has been solved by the grooving of tablets so that the consumer is able as and when required to use only half a dosage unit simply by breaking the tablet in half. This method is difficult to apply to large dosage units because excessive force is required. Another disadvantage is that, although the quantity can be determined, the individual units all have the same composition so that selective dosage of individual ingredients is impossible.
A solution to both problems would be to offer the consumer smaller dosage units varying in composition. Such a solution is proposed in DE-OS 25 21 883. This document describes a detergent composition in the form of tablets, envelopes, bags, packs, capsules or other containers in which the ingredients are present in separate individual units and each individual unit is of such a size that between 1 and 10 individual units of each of these ingredients is/are present in the detergent composition which forms the required wash liquor after dissolution in water. In the document in question, the components are separated into individual units in order to produce detergents with different properties, for example heavy-duty or light-duty detergents, through the controlled supply of individual units.
Dishwasher detergents are not mentioned in the cited document.
Unfortunately, the detergents mentioned have the disadvantage that the individual tablets either do not allow separation of the active ingredients or are very large and thus do not lend themselves to multiple portioning, especially in the case of dishwasher tablets, because the dispensing compartments are often very small.
Now, the problem addressed by the present invention was to provide detergent tablets - and a process for their production - which would allow active ingredients to be separated, if desired, and which would also provide for space-saving multi-unit dosage in narrow dispensing compartments.
Description of the Invention Accordingly, the present invention relates to a detergent tablet of compacted particulate detergent containing builders and optionally other detergent ingredients, characterized in that it has one or more elevations and/or depressions on or in its upper surface and one or more depressions and/or elevations in or on its underneath planoparallel to its upper surface which are designed to interengage.
The term "detergent tablet" in the context of the present invention is not meant to be limiting. As already mentioned, it is also understood to encompass laundry detergent, dishwashing detergent, cleaning and washing-aid tablets. The principle described above enables the consumer to stack several of the tablets according to the invention on top of one another in a space-saving manner through the interengagement of the elevations and depressions on or in the upper surface of the first tablet in the depressions and elevations in or on the underneath of the second tablet. In this way, two, three, four or more tablets can be stacked on top of one another and introduced into the dispensing compartment without any space problems arising and without the dispensing compartment having to be repeatedly loaded with the individual units by the consumer.
The tablets according to the invention can be formed with a plurality of elevations and depressions so that their planoparallel upper and lower surfaces can interengage even when a tablet is stacked laterally offset on a second tablet. This principle is similar to that of children's building blocks.
According to the invention, however, a geometrically simpler shape where the detergent tablet has one elevation and/or depression on or in its upper surface and one depression and/or elevation in or on its underneath, which are designed to interengage, is preferred from the point of view of the production of the tablets.
With only one of these elevations or depressions, the risk of the powder mixtures to be tabletted caking on the tabletting tools is reduced. If the tabletting tools have no vertical edges from their upper surface to the highest point of the elevation or from their lower surface to the lowest point of the depression, further process-related advantages, such as further reduced caking and longer tool lives, are obtained. According to the invention, therefore, preferred detergent tablets are characterized in that the elevations and the depressions in which they engage are in the form of a semi-ellipsoid, a spherical segment or a geometrically similar shape.
According to the invention, the basal surface of the tablets, i.e. the upper or lower surface with the elevations and/or depressions, may assume various geometric forms ranging from the triangle via the rectangle and its special case, the square, to pentagonal, hexagonal or octagonal forms. The basal surface may also readily assume the form of other geometric symbols, such as stars or circles, ellipses or animal shapes.
Preferred detergent tablets are characterized in that the basal surface of the tablet is substantially rectangular and preferably has rounded corners.

Should the embodiment mentioned above not be wanted, a preferred detergent tablet is characterized in that its basal surface is substantially round.
The elevations and depressions may assume any size. However, in the interests of the stability of the resulting tablets, it has been found to be of advantage if the height of the elevations or the depth of the depressions is at most 1/50th to 1/3rd, preferably 1/40th to one quarter, more preferably 1 /30th to 1 /5th and most preferably 1 /20th to 1 /6th of the distance between the parallel sides of the tablet. The spatial extent of the elevations or depressions, i.e. both the proportion of the area covered by the elevations/depressions on or in the basal area of the tablet and their height, is preferably selected so that the elevations/depressions have a volume which makes up a certain percentage of the total tablet volume.
Accordingly, preferred detergent tablets according to the invention are characterized in that the volume of the elevations or depressions makes up 1/100th to 1/3rd, preferably 1/75th to one quarter, more preferably 1/50th to 1/5th and most preferably 1/25th to 1/10th of total tablet volume.
The tablets produced in accordance with the invention may be stacked on top of one another almost endlessly. According to the invention, however, "end pieces" may be produced by making a tablet where the depression has been filled and so is unable to accommodate the elevation of another tablet. Accordingly, the present invention also relates to detergent tablets where the depressions) in one of the tablet sides is/are filled with a fusible material.
The present invention also relates to a process for the production of the tablets according to the invention. The process according to the invention is a tabletting process known per se in which specially shaped punches are used, i.e. a process for the production of detergent tablets by compressing particulate detergent in known manner in a tablet press with top and bottom punches, characterized in that the top punch has one or more elevations and/or depressions on or in its contact surface while the bottom punch has one or more depressions and/or elevations in or on its contact surface which are designed to interengage.
The same preferred embodiments applying to the tablets according 5 to the invention apply to the tabletting process according to the invention.
Particularly preferred processes according to the invention are characterized in that the top punch has an elevation which is preferably in the form of a semi-ellipsoid, a spherical section or a geometrically similar shape. In this embodiment of the process, the bottom punch - logically -has a depression of complementary shape.
In accordance with standard sizes of detergent tablets (ca. 10 to under 100 cubic centimeters), particularly preferred processes according to the invention are characterized in that the elevation has a volume of 0.5 to 5 ml, preferably 0.6 to 3 ml and more preferably 0.8 to 2 ml.
Tablets with various compositions can be made by the process according to the invention. In particular, the process according to the invention minimizes the problems involved in the manufacture and use of dishwasher tablets. Such tablets normally contain only small amounts of surfactants.
Laundry detergent tablets are normally produced by mixing surfactant granules with aftertreatment components and then tabletting the resulting particulate premix. Accordingly, preferred variants of the process according to the invention are characterized in that the particulate premix contains surfactant-containing granules and has a bulk density of at least 500 g/I, preferably of at least 600 g/I and more preferably of at least 700 g/I.
Accordingly, preferred processes according to the invention comprise the tabletting of a particulate premix of at least one batch of surfactant-containing granules and at least one added powder-form component. The surfactant-containing granules may be produced by standard industrial granulation processes, such as compacting, extrusion, mixer granulation, pelleting or fluidized bed granulation.
In preferred process variants, the surfactant-containing granules satisfy certain particle size criteria. Thus, preferred processes according to the invention are characterized in that the surfactant-containing granules have particle sizes of 100 to 2,000 Nm, preferably 200 to 1,800 Nm, more preferably 400 to 1,600 Nm and most preferably 600 to 1400 Nm.
Besides the active substances (anionic and/or nonionic andlor cationic and/or amphoteric surfactants), the surfactant granules preferably contain carrier materials which, in one particularly preferred embodiment, emanate from the group of builders. Particularly advantageous processes are characterized in that the surfactant-containing granules contain anionic and/or nonionic surfactants and builders and have total surfactant contents of at least 10% by weight, preferably of at least 15% by weight and more preferably of at least 20% by weight.
These surface-active substances emanate from the group of anionic, nonionic, zwitterionic and cationic surfactants, anionic surfactants being preferred on economic grounds 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 C~~3 alkyl benzenesulfonates, olefin sulfonates, i.e. mixtures of alkene and hydroxy-alkane sulfonates, and the disulfonates obtained, for example, from C~2_~$
monoolefins with an internal or terminal double bond by sulfonation with gaseous sulfur trioxide and subsequent alkaline or acidic hydrolysis of the sulfonation products. Other suitable surfactants of the sulfonate type are the alkane sulfonates obtained from C~2_~8 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_~a fatty alcohols, for example cocofatty alcohol, tallow fatty 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, 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 C~~~ 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 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.
According to the invention, preferred surfactant granules are those which contain 5 to 50% by weight, preferably 7.5 to 40% by weight and more preferably 10 to 30% by weight of anionic surfactant(s), based on the granules.
So far as the choice of anionic surfactants is concerned, there are no basic requirements to restrict the freedom of formulation. However, preferred surfactant granules do have a soap content in excess of 0.2% by weight, based on the total weight of the detergent tablet produced in step d). Preferred anionic surfactants are 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 of 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 moiety may be linear or, preferably, methyl-branched in the 2-position or may contain linear and methyl-branched radicals in the form of the mixtures typically present in oxoalcohol radicals. However, alcohol ethoxylates containing linear radicals of alcohols of native origin with 12 to 18 carbon atoms, for example coconut oil, palm oil, tallow 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, C~» alcohol containing 7 EO, C»~5 alcohols containing 3 EO, 5 EO, 7 EO or 8 EO, C~2_~8 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-~s 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 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 581217598 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 5 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 10 polyglycosyl component is a glucose unit and the alkyl moiety is an n-alkyl group, are preferably used.
The surfactant granules 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 5% 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-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 (II):
R' R-CO-N-[Z] (I 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 (III):
R'-O-R2 R-CO-N-[Z] (I 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 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-95107331.
Irrespective of whether anionic or nonionic surfactants or mixtures of surfactants belonging to these classes and optionally amphoteric or cationic surfactants are used in the surfactant granules, preferred processes according to the invention are those in which the surfactant content of the surfactant-containing granules is 5 to 60% by weight, preferably 10 to 50% by weight and more preferably 15 to 40% by weight, based on the surfactant granules.
The surfactant granules may be used in varying amounts in the detergent tablets. Processes according to the invention in which the surfactant-containing granules make up 40 to 95% by weight, preferably 45 to 85% by weight and more preferably 55 to 75% by weight of the detergent tablets are preferred. As mentioned above, dishwasher tablets normally contain only small quantities of surfactants so that the foregoing observations do not apply to this class of detergent tablets.
Besides the detersive substances, builders are the most important ingredients of detergents. Any of the builders normally used in detergents may be present in the surfactant granules or - where no surfactant granules are used - even as part of the premix, including in particular zeolites, silicates, carbonates, organic co-builders and also - providing there are no ecological objections to their use - phosphates.
Suitable crystalline layered sodium silicates correspond to the general formula NaMSiXO~+~y H20, where M is sodium or hydrogen, x is a number of 1.9 to 4 and y is a number of 0 to 20, preferred values for x being 2, 3 or 4. Crystalline layered silicates such as these are described, for example, in European patent application EP-A-0 164 514. Preferred crystalline layered silicates corresponding to the above formula are those in which M is sodium and x assumes the value 2 or 3. Both Vii- and 8-sodium disilicates Na2Si205y H20 are particularly preferred, ~-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 (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 may be interpreted to mean that the products have microcrystalline regions between 10 and a few hundred nm in size, values of up to at most 50 nm and, more particularly, up to at most 20 nm being preferred. So-called X-ray amorphous silicates such as these, which also dissolve with delay in relation to conventional waterglasses, are described for example in German patent application DE-A-44 00 024. Compacted amorphous silicates, compounded amorphous silicates and overdried X-ray-amorphous silicates are particularly preferred.
If desired, more zeolite besides the quantity of P and/or X zeolite introduced through the surfactant granules can be incorporated in the premix by adding zeolite as an aftertreatment component. The finely crystalline, synthetic zeolite containing bound water used in accordance with the invention is preferably a zeolite of the A, P, X or Y type. However, zeolite X and mixtures of A, X and/or P are also suitable. 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 their use is not ecologically unsafe, and mixtures thereof. Preferred salts are the salts of the polycarboxylic acids, such as citric acid, adipic acid, succinic acid, glutaric acid, tartaric acid, sugar acids and mixtures thereof.
In addition, the detergent tablets produced in accordance with the invention may contain 0.5 to 5% by weight and preferably 1 to 3% by weight of a polycarboxylate polymer containing (meth)acrylate and/or maleate units as additional co-builders and discoloration inhibitors. These anionic polymers may be used in their acid form or in the form of completely or partly neutralized salts. Preferred polymers are homo-polymers and copolymers of acrylic acid. Polyacrylates, acrylic acid/maleic acid copolymers and acrylic phosphinates are particularly preferred.
Polyacrylates are commercially available, for example, under the names of Versicol~ E5, Versicol~ E7 and Versicol~ E9 (trade marks of Allied Colloids), Narlex~ LD 30 and Narlex LD 34 (trade marks of National Adhesives), Acrysol~ LMW 10, Acrysol~ LMW-20, Acrysol~ LMW-45 and Acrysol~ A1-N (trade marks of Rohm & Haas) and Sokalan~ PA-20, Sokalan~ PA-40, Sokalan~ PA-70 and Sokalan~ PA-110 (trade marks of BASF). Ethylene/maleic acid copolymers are marketed under the name of EMA~ (trade mark of Monsanto), methyl vinyl ether/maleic acid copoly-mers are marketed under the name of Gantrez~ AN 119 (trade mark of GAF Corp.) and acrylic acid/maleic acid copolymers are marketed under the name of Sokalan~ CP5 and Sokalan~ CP7 (trade marks of BASF).
Acrylic phosphinates are obtainable as DKV11~ (trade mark of National Adhesives) and Belperse~ (trade mark of Ciba Geigy) types. Graft copolymers obtained by grafting polyalkylene oxides having molecular weights of 2,000 to 100,000 with vinyl acetate may also be used in combination with the polymers mentioned or as sole discoloration inhibitor.
The acetate groups may optionally be up to 15% saponified. Polymers of this type, which are described in European patent application EP-A-0 219 5 048 (BASF), are marketed under the name of Sokalan~ HP22 (trade mark of BASF).
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 10 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 15 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 Wley & 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 need not necessarily belong to zeolite structural group 4, may also be used as powdering materials, 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 compound which contains granular components and powders subsequently added, the powder-form components subsequently added or one of the powder-form components subsequently added 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 tabletted.
According to the invention, detergent tablets additionally containing a disintegration aid are preferred. Processes according to the invention in which the premix additionally contains a disintegration aid, preferably a cellulose-based disintegration aid, preferably in granular, co-granulated or compacted form, in quantities of 0.5 to 10% by weight, preferably in quantities of 3 to 7% by weight and more preferably in quantities of 4 to 6%
by weight, based on the weight of the premix, are also preferred. In addition to or instead of the ingredients mentioned (surfactant, builder and disintegration aid), the particulate premixes to be tabletted in the process according to the invention may additionally contain one or more substances from the group of bleaching agents, bleach activators, enzymes, pH
regulators, fragrances, perfumes, 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 are, for example, sodium percarbonate, peroxypyrophosphates, citrate perhy-drates and H202-yielding peracidic salts or peracids, such as perbenzoates, peroxophthalates, diperazelaic acid, phthaloiminoperacid or diperdodecane dioic acid. Even where bleaching agents are used, there is no need for surfactants and/or builders so that pure bleaching tablets can be produced. If such bleaching tablets are to be added to the washing, a combination of sodium percarbonate with sodium sesquicarbonate is preferred, irrespective of which other ingredients are present in the tablets.
If detergent or bleaching tablets for dishwashing machines are being produced, 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 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, e-phthalimidoperoxycaproic acid [phthaoiminoperoxyhexanoic acid (PAP)], o-carboxybenzamido-peroxycaproic acid, N-nonenylamidoperadipic acid and N-nonenyl-amidopersuccinates, 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-aminoper-caproic acid).
Other suitable bleaching agents in tablets for dishwashing machines are chlorine- and bromine-releasing substances. Suitable chlorine- or bromine-releasing materials are, for example, heterocyclic N-bromamides and N-chloramides, for example trichloroisocyanuric acid, tribromo-isocyanuric acid, dibromoisocyanuric acid and/or dichloroisocyanuric acid (DICA) and/or salts thereof with cations, such as potassium and sodium.
Hydantoin compounds, such as 1,3-dichloro-5,5-dimethyl hydantoin, are also suitable.
In order to obtain an improved bleaching effect where washing is carried out at temperatures of 60°C or lower, bleach activators may be incorporated as sole constituent or as an ingredient of component b). The bleach activators may be compounds which form aliphatic peroxocarboxylic acids containing preferably 1 to 10 carbon atoms and more preferably 2 to 4 carbon atoms and/or optionally substituted perbenzoic acid under perhydrolysis conditions. 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 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 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 produced in accordance with the invention may be, for example, from about 0.1 to 5% by weight and is preferably from 0.1 to about 2% by weight.
In addition, the 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 hydroxypropoxyl groups, based on the nonionic cellulose ether, and the polymers of phthalic acid and/or terephthalic acid known from the prior art or derivatives thereof, more particularly polymers of ethylene terephthalates and/or polyethylene glycol terephthalates or anionically and/or nonionically modified derivatives thereof. Of these, the sulfonated derivatives of phthalic acid and terephthalic acid polymers are particularly preferred.
The tablets may contain derivatives of diamino-stilbenedisulfonic acid or alkali metal salts thereof as optical brighteners. Suitable optical brighteners are, for example, salts of 4,4'-bis-(2-anilino-4-morpholino-1,3,5-triazinyl-6-amino)-stilbene-2,2'-disulfonic acid or compounds of similar com-position which contain a diethanolamino group, a methylamino group, an anilino group or a 2-methoxyethylamino group instead of the morpholino group. Brighteners of the substituted Biphenyl styryl type, for example alkali metal salts of 4,4'-bis-(2-sulfostyryl)-Biphenyl, 4,4'-bis-(4-chloro-3-sulfostyryl)-Biphenyl or 4-(4-chlorostyryl)-4'-(2-sulfostyryl)-Biphenyl, may also be present. Mixtures of the brighteners mentioned above may also be used.
Dyes and fragrances are added to the detergent tablets produced in accordance with the invention to improve the aesthetic impression created 5 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 10 compounds of the ester type are, for example, benzyl acetate, phenoxy-ethyl 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 15 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, 20 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 fragrances may be directly incorporated in the tablets produced in accordance with 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 com-plexes optionally being coated with other auxiliaries.
In order to improve their aesthetic impression, the tablets produced in accordance with 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 detergent tablets or by light and do not have any pronounced substantivity for textile fibers so as not to color them.

Claims (10)

1. A detergent tablet of compacted particulate detergent containing builders and optionally other detergent ingredients, characterized in that it has one or more elevations and/or depressions on or in its upper surface and one or more depressions and/or elevations in or on its underneath planoparallel to its upper surface which are designed to interengage.

2. A detergent tablet as claimed in claim 1, characterized in that has one elevation and/or depression on or in its upper surface and one depression and/or elevation in or on its underneath which are designed to interengage.

3. A detergent tablet as claimed in claim 1 or 2, characterized in that the elevations or the depressions in which they engage are in the form of a semi-ellipsoid, a spherical section or a geometrically similar shape.

4. A detergent tablet as claimed in any of claims 1 to 3, characterized in that its base is substantially rectangular and preferably has rounded corners.

5. A detergent tablet as claimed in any of claims 1 to 3, characterized in that its base is substantially round.

6. A detergent tablet as claimed in any of claims 1 to 5, characterized in that the volume of the elevations or depressions makes up 1/100th to 1/3rd, preferably 1/75th to one quarter, more preferably 1/50th to 1/5th and most preferably 1/25th to 1/10th of total tablet volume.

7. A detergent tablet as claimed in any of claims 1 to 6, characterized in that the depression(s) in one of the tablet sides are filled with a fusible material.

8. A process for the production of detergent tablets by compressing particulate detergent in known manner in a tablet press with top and bottom punches, characterized in that the top punch has one or more elevations and/or depressions on or in its contact surface while the bottom punch has one or more depressions and/or elevations in or on its contact surface which are designed to interengage.

9. A process as claimed in claim 8, characterized in that the top punch has an elevation which is preferably in the form of a semi-ellipsoid, a spherical section or a geometrically similar shape.

10. A process as claimed in claim 8 or 9, characterized in that the elevation has a volume of 0.5 to 5 ml, preferably 0.6 to 3 ml and more preferably 0.8 to 2 ml.