CA2307430A1 - Washing process using detergent tablets - Google Patents

Abstract

The disadvantages of detergent tablets dispensed via the drum of a washing machine, more particularly elimination of the need to use dispensers without any problems arising in regard to dissolving behavior or spotting, can be avoided by a process for washing laundry using detergent tablets in a domestic washing machine in which the detergent tablets are added to the washing in the drum without a dispensing aid before the washing process and contain sodium percarbonate.

Description

Washing Process Using Detergent Tablets Field of the Invention This invention relates to a process for washing laundry in a domestic washing machine using detergents in the form of shaped bodies which are referred to in short hereinafter as detergent tablets.
Background of the Invention Detergent compositions in the form of tablets have long been known and are widely described in the prior art although, until recently, tablets had not been especially prominent on the market. The reason for this is that tablets, despite a number of advantages, also have disadvantages which have an adverse effect both on their production and use and on their acceptance by consumers. The main advantages of tablets, such as elimination of the need to measure out the quantity of product required by the consumer, the higher density and hence the reduced packaging and storage costs and an aesthetic aspect which should not be underestimated, are offset by such disadvantages as the dichotomy between acceptable hardness and sufficiently rapid disintegration and dissolution of the tablets and numerous technological difficulties in production and packaging.
Extensive prior art literature has been available, especially recently, on solutions to these problems and tablets are now marketed across Europe as a supply form for detergents.
Hitherto, only two methods have been developed for the dispensing of detergent tablets by the consumer. On the one hand, dispensing aids are included with the tablets in the retail pack, the tablets having to be inserted into these dispensing aids before use. The dispenser, including the tablet inserted therein, is then added to the laundry in the washing drum. These dispensers, which generally have a net-like construction, are supposed to prevent direct contact between the detergent tablets and the laundry because the sometimes fairly long dissolving times without a dispenser would lead to direct contact between tablet residues and the laundry which, in turn, can cause local decoloration or lightening in color of the laundry. Another function of the dispenser is to improve the dissolving behavior of tablets in drum-type washing machines. Since the washing drum is inclined slightly forwards, it can happen that the tablet is pressed by the moving laundry into the gap between the sealing ring and the bull's-eye. The water has hardly any chance of reaching the tablet on this rubber collar, so that the tablet remains behind on the rubber collar either undissolved or disintegrating too slowly. Accordingly, the consumer on the one hand has the inconvenience of a relatively poor washing result, because the active substance of the undissolved tablet is either unavailable or is available too late in the wash cycle; on the other hand, having to remove tablet remains from the rubber collar is also an inconvenience to the consumer. The dispensers are supposed to prevent this phenomenon because the moving laundry engages part of the dispensing "net" or solid tablet and entrains the dispenser, even if it should happen to be present on the rubber collar.
On the other hand, detergent tablets are available on the market which can be flushed into the washing process from the dispensing compartment of domestic washing machines in the same way as conventional washing powders. Since these tablets disintegrate in the dispensing compartment itself and hence are flushed into the machine as powders, they are not attended by the above-mentioned problem known as pinhole spotting. However, in view both of the small amount of water used for flushing and the short flushing time, detergent tablets of the type in question have to meet much more stringent requirements than conven-tional tablets and dispensers.
The problem of spotting in the case of in-drum dispensing occurs in particular with tablets containing bleaching agents. The direct contact of the moistened bleach-containing tablet with the laundry results locally in a high concentration of peroxygen which is capable of bleaching dyes.
Bleach-containing detergent tablets are also widely described in the prior art literature:

Thus, European patent application EP-A-0 481 793 (Unilever) describes detergent tablets in which individual ingredients are separated from others. The detergent tablets disclosed in this document contain sodium percarbonate which is separated from all other components that could influence its stability. The document in question does not contain any particulars of the particle size or the dispensing of the final detergent tablets.
Detergent tablets containing sodium percarbonate are described in earlier German patent application DE 198 43 778.1 (Henkel KGaA). The tablets described therein are distinguished by high hardness and by a high disintegration rate because at least 60% by weight of the sodium percarbonate present in them consists of particles smaller than 0.8 mm in size. Following the teaching of the patent application in question, it is possible to produce detergent tablets which can be flushed into the washing process from the dispensing compartment of domestic washing machines.
International patent application WO 98142816 (Unilever) describes detergent tablets in which the bleaching agent is selected from sodium perborate tetrahydrate, sodium percarbonate or mixtures thereof. The document in question does not contain any particulars of the application of these tablets.
The problem addressed by the present invention was to avoid the disadvantages of detergent tablets designed for dispensing via the washing drum. More particularly, the problem addressed by the present invention was to provide a washing process in which there would be no need to use dispensers, but which would still be free from problems in regard to dissolving behavior and spotting. Since the insertion of the tablet into a dispenser and the closing of the dispenser are regarded by the consumer as additional and unnecessary steps, the invention set out to provide a washing process which would enable the consumer to dispense tablets via the washing drum without any burdensome extra effort.

Description of the Invention It has now been found that a washing process in which the detergent tablets dispensed via the washing drum contain sodium percarbonate fulfils the stated requirements.
The present invention relates to a process for washing laundry using detergent tablets in a domestic washing machine, characterized in that the detergent tablets are added to the laundry in the drum without a dispensing aid before the washing process and contain sodium percarbonate.
It has been found that the washing process according to the inven-tion overcomes the disadvantages described above. Detergent tablets containing sodium percarbonate may be directly introduced into the drum in the washing process according to the invention without any need to use a dispensing aid to avoid dissolving or spotting problems.
To develop the required bleaching effect, the detergent tablets used in the washing process according to the invention contain sodium percarbonate. "Sodium percarbonate" is a non-specific term used for sodium carbonate peroxohydrates which, strictly speaking, are not "percarbonates" (i.e. salts of percarbonic acid), but hydrogen peroxide adducts with sodium carbonate. The commercial material has the mean composition 2 Na2C03 ~ 3 H202 and, accordingly, is not a peroxycarbonate.
Sodium percarbonate forms a white water-soluble powder with a density of 2.14 gcm3 which readily decomposes into sodium carbonate and bleaching or oxidizing oxygen.
Sodium carbonate peroxohydrate was obtained for the first time in 1899 by precipitation with ethanol from a solution of sodium carbonate in hydrogen peroxide, but was mistakenly regarded as peroxycarbonate. It was only in 1909 that the compound was recognised as a hydrogen peroxide addition compound. Nevertheless, the historical name "sodium percarbonate" has been adopted in practice.
On an industrial scale, sodium percarbonate is mainly produced by precipitation from aqueous solution (so-called wet process). In this pro-cess, aqueous solutions of sodium carbonate and hydrogen peroxide are combined and the sodium percarbonate is precipitated by salting-out agents (mainly sodium chloride), crystallization aids (for example polyphos-phates, polyacrylates) and stabilizers (for example Mg2+ ions). The 5 precipitated salt which still contains 5 to 12% by weight of mother liquor is then removed by centrifuging and dried at 90°C in fluidized bed dryers.
The bulk density of the end product can vary between 800 and 1200 gll according to the production process. In general, the percarbonate is stabilized by an additional coating. Coating processes and materials are widely described in the patent literature. Basically, any commercially available percarbonate types as marketed, for example, by Solvay Interox, Degussa, Kemira and Akzo may be used in accordance with the present invention. According to the invention, the advantageousness of the rapid tablet disintegration stems from the defined particle size of the percarbonate.
The sodium percarbonate is used in varying quantities according to the required performance of the product. Normal contents are between 5 and 50% by weight, preferably between 10 and 40% by weight and more preferably between 15 and 35% by weight, based on the tablet as a whole.
Preferred washing processes according to the invention are characterized in that the detergent tablets used contain sodium percarbonate in quantities of 1 to 40% by weight, preferably in quantities of 5 to 30% by weight and more preferably in quantities of 10 to 25% by weight, based on tablet weight.
The advantageousness of using sodium percarbonate within certain particle size ranges described in the prior art literature can also be applied to the process according to the invention. Thus, preferred washing processes are characterized in that at least 60% by weight, preferably at least 70% by weight, more preferably at least 80% by weight and most preferably at least 90% by weight of the sodium percarbonate particles present in the detergent tablets have a particle size below 0.8 mm. In one particularly preferred embodiment, the sodium percarbonate present in the tablets is substantially free from particles larger than 1.2 mm in size.
In addition to the sodium percarbonate, the detergent tablets used in the washing process according to the invention may contain bleach activators) which represents a preferred embodiment of the present invention. Bleach activators are incorporated in detergents in order to obtain an improved bleaching effect at washing temperatures of 60°C or lower. According to the invention, compounds which form aliphatic peroxocarboxylic acids preferably containing 1 to 10 carbon atoms and more preferably 2 to 4 carbon atoms andlor optionally substituted perbenzoic acid under perhydrolysis conditions may be used as bleach activators. Suitable bleach activators are substances which contain O-and/or N-acyl groups with the number of carbon atoms indicated and/or optionally substituted benzoyl groups. Preferred bleach activators are polyacylated alkylenediamines, more especially tetraacetyl ethylenediamine (TAED), acylated triazine derivatives, more particularly 1,5-diacetyl-2,4-dioxohexahydro-1,3,5-triazine (DADHT), acylated glycol urils, more particularly tetraacetyl glycol uril (TAGU), N-acylimides, more particularly N-nonanoyl succinimide (NOSI), acylated phenol sulfonates, more particularly n-nonanoyl- or isononanoyl-oxybenzenesulfonate (n- or iso-NOBS), carboxylic anhydrides, more especially phthalic anhydride, acylated polyhydric alcohols, more especially triacetin, ethylene glycol diacetate and 2,5-diacetoxy-2,5-dihydrofuran.
In addition to or instead of the conventional bleach activators, 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, Mn-, Fe-, Co-, Ru- or Mo-salen complexes or carbonyl complexes. Mn-, Fe-, Co-, Ru-, Mo-, Ti-, V- and Cu-complexes with N-containing tripod ligands and Co-, Fe-, Cu- and Ru-ammine complexes may also be used as bleach catalysts.
The tablets used in the washing process according to the invention normally contain between 0.5 and 30% by weight, preferably between 1 and 20% by weight and more preferably between 2 and 15% by weight -based on the tablet as a whole - of one or more bleach activators or bleach catalysts. These quantities may vary according to the application envisaged for the tablets. Thus, in typical heavy-duty detergent tablets, bleach activator contents of 0.5 to 10% by weight, preferably 2 to 8% by weight and more preferably 4 to 6% by weight are normal whereas bleach tablets can have much higher contents, for example between 5 and 30% by weight, preferably between 7.5 and 25% by weight and more preferably between 10 and 20% by weight. The expert is not restricted in his freedom of formulation and is able in this way to produce laundry detergent tablets, dishwasher tablets or bleach tablets with a stronger or weaker bleaching effect by varying the contents of bleach activator and bleaching agent.
Particularly preferred bleach activators are N,N,N',N'-tetraacetyl ethylenediamine, which is widely used in laundry/dishwasher detergents, and n-nonanoyloxybenzenesulfonate (NOBS). Accordingly, preferred detergent tablets are characterized in that they contain tetraacetyl ethylenediamine in the quantities mentioned above as bleach activator.
Besides the ingredients mentioned above, the detergent tablets used in the washing process according to the invention may contain other ingredients in quantities determined by the particular application envisaged for the tablets. Thus, substances from the groups of surfactants, builders and polymers are particularly suitable for use in the detergent tablets according to the invention. The expert will again have no difficulty in selecting the individual components and the quantities in which to use them. Thus, a heavy-duty detergent tablet will contain relatively large quantities of surfactants) whereas a bleach tablet may well contain no surfactant at all. The quantity of builders) used also varies according to the particular application envisaged.
The detergent tablets used in the washing process according to the invention according to the invention may contain any of the builders normally used in detergents, i.e. in particular zeolites, silicates, carbonates, organic co-builders and - providing there are no ecological objections to their use - also phosphates.
Suitable crystalline layered sodium silicates correspond to the general formula NaMSixO~+~A 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 ~3- and 8-sodium disilicates Na2Si205A y H20 are particularly preferred, ~3-sodium disilicate being obtainable, for example, by the process described in International patent application WO-A- 91!08171.
Other useful builders are amorphous sodium silicates with a modulus (Na20:Si02 ratio) of 1:2 to 1:3.3, preferably 1:2 to 1:2.8 and more preferably 1:2 to 1:2.6 which dissolve with delay and exhibit multiple wash cycle properties. The delay in dissolution in relation to conventional amorphous sodium silicates can have been obtained in various ways, for example by surface treatment, compounding, compacting or by overdrying.
In the context of the invention, the term "amorphous" is also understood to encompass "X-ray amorphous". In other words, the silicates do not produce any of the sharp X-ray reflexes typical of crystalline substances in X-ray diffraction experiments, but at best one or more maxima of the scattered X-radiation which have a width of several degrees of the diffraction angle. However, particularly good builder properties may even be achieved where the silicate particles produce crooked or even sharp diffraction maxima in electron diffraction experiments. This may be interpreted to mean that the products have microcrystalline regions between 10 and a few hundred nm in size, values of up to at most 50 nm and, more particularly, up to at most 20 nm being preferred. So-called X-ray amorphous silicates such as these, which also dissolve with delay in relation to conventional waterglasses, are described for example in German patent application DE-A-44 00 024. Compacted amorphous silicates, compounded amorphous silicates and overdried X-ray-amorphous silicates are particularly preferred.
The finely crystalline, synthetic zeolite containing bound water used in accordance with the invention is preferably zeolite A andlor zeolite P.
Zeolite MAP~ (Crosfield) is a particularly preferred P-type zeolite.
However, zeolite X and mixtures of A, X and/or P are also suitable.
According to the invention, it is also preferred to use, for example, a co-crystallizate of zeolite X and zeolite A (ca. 80% by weight zeolite X) which is marketed by CONDEA Augusta S.p.A. under the name of VEGOBOND
AX~ and which may be described by the following formula:
nNa20 ~ (1-n)K20 ~ AI203 ~ (2 - 2.5)Si02 ~ (3.5 - 5.5) H20.
The zeolite may be used both as a builder in a granular compound and as a kind of "powder" to be applied to the entire mixture to be tabletted, both routes normally being used to incorporate the zeolite in the premix.
Suitable zeolites have a mean particle size of less than 10 ~m (volume distribution, as measured by the Coulter Counter Method) and contain preferably 18 to 22% by weight and more preferably 20 to 22% by weight of bound water.
The generally known phosphates may of course also be used as builders providing their use should not be avoided on ecological grounds.
Among the large number of commercially available phosphates, alkali metal phosphates have the greatest importance in the detergent industry, pentasodium triphosphate and pentapotassium triphosphate (sodium and potassium tripolyphosphate) being particularly preferred.
"Alkali metal phosphates" is the collective term for the alkali metal (more particularly sodium and potassium) salts of the various phosphoric acids, including metaphosphoric acids (HP03)~ and orthophosphoric acid (H3P04) and representatives of higher molecular weight. The phosphates combine several advantages: they act as alkalinity sources, prevent lime deposits on machine parts and lime incrustations in fabrics and, in addition, contribute towards the cleaning effect.
5 Sodium dihydrogen phosphate (NaH2P04) exists as the dihydrate (density 1.91 gcm3, melting point 60°) and as the monohydrate (density 2.04 gcm3). Both salts are white readily water-soluble powders which, on heating, lose the water of crystallization and, at 200°, are converted into the weakly acidic diphosphate (disodium hydrogen diphosphate, Na2H2P20~) 10 and, at higher temperatures, into sodium trimetaphosphate (Na3P309) and Maddrell's salt (see below). NaH2P04 shows an acidic reaction. It is formed by adjusting phosphoric acid with sodium hydroxide to a pH value of 4.5 and spraying the resulting "mash". Potassium dihydrogen phosphate (primary or monobasic potassium phosphate, potassium biphosphate, KDP), KH2P04, is a white salt with a density of 2.33 gcm3, has a melting point of 253° [decomposition with formation of potassium polyphosphate (KP03)X] and is readily soluble in water.
Disodium hydrogen phosphate (secondary sodium phosphate), Na2HP04, is a colorless, readily water-soluble crystalline salt. It exists in water-free form and with 2 moles (density 2.066 gcm3, water loss at 95°), 7 moles (density 1.68 gcm3, melting point 48° with loss of 5 H20) and 12 moles of water (density 1.52 gcm3, melting point 35° with loss of 5 H20), becomes water-free at 100° and, on fairly intensive heating, is converted into the diphosphate Na4P207. Disodium hydrogen phosphate is prepared by neutralization of phosphoric acid with soda solution using phenol-phthalein as indicator. Dipotassium hydrogen phosphate (secondary or dibasic potassium phosphate), K2HP04, is an amorphous white salt which is readily soluble in water.
Trisodium phosphate, tertiary sodium phosphate, Na3P04, consists of colorless crystals which have a density of 1.62 gcm' and a melting point of 73-76° (decomposition) as the dodecahydrate, a melting point of 100° as the decahydrate (corresponding to 19-20% P205) and a density of 2.536 gcm3 in water-free form (corresponding to 39-40% P2O5). Trisodium phosphate is readily soluble in water through an alkaline reaction and is prepared by concentrating a solution of exactly 1 mole of disodium phosphate and 1 mole of NaOH by evaporation. Tripotassium phosphate (tertiary or tribasic potassium phosphate), K3P04, is a white deliquescent granular powder with a density of 2.56 gcm3, has a melting of 1340° and is readily soluble in water through an alkaline reaction. It is formed, for example, when Thomas slag is heated with coal and potassium sulfate.
Despite their higher price, the more readily soluble and therefore highly effective potassium phosphates are often preferred to corresponding sodium compounds in the detergent industry.
Tetrasodium diphosphate (sodium pyrophosphate), Na4P207, exists in water-free form (density 2.534 gcm3, melting point 988°, a figure of 880°
has also been mentioned) and as the decahydrate (density 1.815 - 1.836 gcm3, melting point 94° with loss of water). Both substances are colorless crystals which dissolve in water through an alkaline reaction. Na4P207 is formed when disodium phosphate is heated to >200° or by reacting phosphoric acid with soda in a stoichiometric ratio and spray-drying the solution. The decahydrate complexes heavy metal salts and hardness salts and, hence, reduces the hardness of water. Potassium diphosphate (potassium pyrophosphate), K4P207, exists in the form of the trihydrate and is a colorless hygroscopic powder with a density of 2.33 gcm3 which is soluble in water, the pH value of a 1 % solution at 25° being 10.4.
Relatively high molecular weight sodium and potassium phosphates are formed by condensation of NaH2P04 or KH2P04. They may be divided into cyclic types, namely the sodium and potassium metaphosphates, and chain types, the sodium and potassium polyphosphates. The chain types in particular are known by various different names: fused or calcined phosphates, Graham's salt, Kurrol's salt and Maddrell's salt. All higher sodium and potassium phosphates are known collectively as condensed phosphates.
The industrially important pentasodium triphosphate, Na5P30~o (sodium tripolyphosphate), is a non-hygroscopic white water-soluble salt which crystallizes without water or with 6 HZO and which has the general formula Na0-[P(O)(ONa)-O]~-Na where n = 3. Around 17 g of the salt free from water of crystallization dissolve in 100 g of water at room temperature, around 20 g at 60° and around 32 g at 100°. After heating of the solution for 2 hours to 100°, around 8% orthophosphate and 15% diphosphate are formed by hydrolysis. In the preparation of pentasodium triphosphate, phosphoric acid is reacted with soda solution or sodium hydroxide in a stoichiometric ratio and the solution is spray-dried. Similarly to Graham's salt and sodium diphosphate, pentasodium triphosphate dissolves many insoluble metal compounds (including lime soaps, etc.). Pentapotassium triphosphate, K5P30~o (potassium tripolyphosphate), is marketed for example in the form of a 50% by weight solution (> 23% P205, 25% K20).
The potassium polyphosphates are widely used in the detergent industry.
Sodium potassium tripolyphosphates, which may also be used in accordance with the invention, also exist. They are formed for example when sodium trimetaphosphate is hydrolyzed with KOH:
(NaP03)3 + 2 KOH ~ Na3K2P30~o + H20 According to the invention, they may be used in exactly the same way as sodium tripolyphosphate, potassium tripolyphosphate or mixtures thereof. Mixtures of sodium tripolyphosphate and sodium potassium tripolyphosphate or mixtures of potassium tripolyphosphate and sodium potassium tripolyphosphate or mixtures of sodium tripolyphosphate and potassium tripolyphosphate and sodium potassium tripolyphosphate may also be used in accordance with the invention.
Organic cobuilders suitable for use in the detergent tablets according to the invention are, in particular, polycarboxylateslpolycarboxylic acids, polymeric polycarboxylates, aspartic acid, polyacetals, dextrins, other organic cobuilders (see below) and phosphonates. These classes of substances are described in the following.
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 which bear 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, aminocarboxylic 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.
The acids per se may also be used. Besides their builder effect, the acids also typically have the property of an acidifying component and, hence, also serve to establish a relatively low and mild pH value in detergents. Citric acid, succinic acid, glutaric acid, adipic acid, gluconic acid and mixtures thereof are particularly mentioned in this regard.
Other suitable builders are polymeric polycarboxylates such as, for example, the alkali metal salts of polyacrylic or polymethacrylic acid, for example those with a relative molecular weight of 500 to 70,000 g/mole.
The molecular weights mentioned in this specification for polymeric polycarboxylates are weight-average molecular weights MW of the particular acid form which, basically, were determined by gel permeation chromatography (GPC) using a UV detector. The measurement was carried out against an external polyacrylic acid standard which provides realistic molecular weight values by virtue of its structural similarity to the polymers investigated. These values differ distinctly from the molecular weights measured against polystyrene sulfonic acids as standard. The molecular weights measured against polystyrene sulfonic acids are generally higher than the molecular weights mentioned in this specification.
Particularly suitable polymers are polyacrylates which preferably have a molecular weight of 2,000 to 20,000 glmole. By virtue of their superior solubility, preferred representatives of this group are the short-chain polyacrylates which have molecular weights of 2,000 to 10,000 glmole and, more particularly, 3,000 to 5,000 glmole.
Also suitable are copolymeric polycarboxylates, particularly those of acrylic acid with methacrylic acid and those of acrylic acid or methacrylic acid with malefic acid. Acrylic acidlmaleic acid copolymers containing 50 to 90% by weight of acrylic acid and 50 to 10% by weight of malefic acid have proved to be particularly suitable. Their relative molecular weights, based on the free acids, are generally in the range from 2,000 to 70,000 g/mole, preferably in the range from 20,000 to 50,000 g/mole and more preferably in the range from 30,000 to 40,000 glmole.
The (co)polymeric polycarboxylates may be used either in powder form or in the form of an aqueous solution. The content of (co)polymeric polycarboxylates in the detergent is preferably from 0.5 to 20% by weight and more preferably from 3 to 10% by weight.
In order to improve solubility in water, the polymers may also contain allyl sulfonic acids, such as allyloxybenzene sulfonic acid and methallyl sulfonic acid, as monomer.
Other particularly preferred polymers are biodegradable polymers of more than two different monomer units, for example those which contain salts of acrylic acid and malefic acid and vinyl alcohol or vinyl alcohol derivatives as monomers or those which contain salts of acrylic acid and 2-alkylallyl sulfonic acid and sugar derivatives as monomers.
Other preferred copolymers are those which are described in German patent applications DE-A-43 03 320 and DE-A-44 17 734 and which preferably contain acrolein and acrylic acidlacrylic acid salts or acrolein and vinyl acetate as monomers.
Other preferred builders are polymeric aminodicarboxylic acids, salts or precursors thereof. Particular preference is attributed to polyaspartic acids or salts and derivatives thereof which, according to German patent application DE-A-195 40 086, are also said to have a bleach-stabilizing effect in addition to their co-builder properties.
Other suitable builders are polyacetals which may be obtained by reaction of dialdehydes with polyol carboxylic acids containing 5 to 7 5 carbon atoms and at least three hydroxyl groups. Preferred polyacetals are obtained from dialdehydes, such as glyoxal, glutaraldehyde, terephthal-aldehyde and mixtures thereof and from polyol carboxylic acids, such as gluconic acid andlor glucoheptonic acid.
Other suitable organic builders are dextrins, for example oligomers 10 or polymers of carbohydrates which may be obtained by partial hydrolysis of starches. The hydrolysis may be carried out by standard methods, for example acid- or enzyme-catalyzed methods. The end products are preferably hydrolysis products with average molecular weights of 400 to 500,000 glmole. A polysaccharide with a dextrose equivalent (DE) of 0.5 to 15 40 and, more particularly, 2 to 30 is preferred, the DE being an accepted measure of the reducing effect of a polysaccharide by comparison with dextrose which has a DE of 100. Both maltodextrins with a DE of 3 to 20 and dry glucose sirups with a DE of 20 to 37 and also so-called yellow dextrins and white dextrins with relatively high molecular weights of 2,000 to 30,000 g/mole may be used.
The oxidized derivatives of such dextrins are their reaction products with oxidizing agents which are capable of oxidizing at least one alcohol function of the saccharide ring to the carboxylic acid function. Dextrins thus oxidized and processes for their production are known, for example, from European patent applications EP-A-0 232 202, EP-A-0 427 349, EP-A-0 472 042 and EP-A-0 542 496 and from International patent applications WO 92118542, WO 93/08251, WO 93116110, WO 94128030, WO 95107303, WO 95112619 and WO 95120608. An oxidized oligosaccharide corresponding to German patent application DE-A-196 00 018 is also suitable. A product oxidized at C6 of the saccharide ring can be particularly advantageous.

Other suitable co-builders are oxydisuccinates and other derivatives of disuccinates, preferably ethylenediamine disuccinate. Ethylenediamine-N,N'-disuccinate (EDDS) is preferably used in the form of its sodium or magnesium salts. Glycerol disuccinates and glycerol trisuccinates 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 the sodium salt, the disodium salt showing a neutral reaction and the tetrasodium salt an alkaline reaction (pH 9).
Preferred aminoalkane phosphonates are ethylenediamine tetramethylene phosphonate (EDTMP), diethylenetriamine pentamethylenephosphonate (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 or as the hepta- and octasodium salts of DTPMP. Of the phosphonates, HEDP is preferably used as a builder. In addition, the aminoalkane phosphonates have a pronounced heavy metal binding capacity. Accordingly, it can be of advantage, particularly where the detergents also contain bleach, to use aminoalkane phosphonates, more particularly 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.
The quantity of builder used is normally between 10 and 70% by weight, preferably between 15 and 60% by weight and more preferably between 20 and 50% by weight. The quantity of builder used is again dependent upon the particular application envisaged, so that bleach tablets can contain larger quantities of builders (for example between 20 and 70%
by weight, preferably between 25 and 65% by weight and more preferably between 30 and 55% by weight) than, for example, laundry detergent tablets (normally 10 to 50% by weight, preferably 12.5 to 45% by weight and more preferably 17.5 to 37.5% by weight).
In preferred washing processes acording to the invention, the detergent tablets additionally contain one or more surfactant(s). Anionic, nonionic, cationic andlor amphoteric surfactants or mixtures thereof may be used in the detergent tablets used in the washing process according to the invention. Mixtures of anionic and nonionic surfactants are preferred from the performance point of view. The total surfactant content of the tablets is from 5 to 60% by weight, based on the weight of the tablet, surfactant contents above 15% by weight being preferred.
The anionic surfactants used are, for example, those of the sulfonate and sulfate type. Preferred surfactants of the sulfonate type are C9_~3 alkyl benzenesulfonates, olefin sulfonates, i.e. mixtures of alkene and hydroxy-alkane 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~2_~8 alkanes 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.
Other suitable anionic surfactants are sulfonated fatty acid glycerol esters, i.e. 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 C6_22 fatty acids, 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_zo 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 C1a_~5 alkyl sulfates 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_~$ fatty alcohols containing 1 to 4 EO, are also suitable. In view of their high foaming capacity, they are normally used in only relatively small quantities, for example in quantities of 1 to 5% by weight, in dishwashing detergents.
Other suitable anionic surfactants are the salts of alkyl sulfosuccinic acid which are also known as sulfosuccinates or as sulfosuccinic acid esters and which represent monoesters and/or diesters of sulfosuccinic acid with alcohols, preferably fatty alcohols and, more particularly, ethoxylated fatty alcohols. Preferred sulfosuccinates contain Cs_~8 fatty alcohol molecules or mixtures thereof. Particularly preferred sulfosuccinates contain a fatty alcohol molecule 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 molecules 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, in particular, 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, palm kernel or tallow acids.
The anionic surfactants, including the soaps, may be present in the form of their sodium, potassium or ammonium salts and as soluble salts of organic bases, such as mono-, di- or triethanolamine. The anionic surfactants are preferably present in the form of their sodium or potassium salts and, more preferably, in the form of their sodium salts.
Preferred nonionic surfactants are alkoxylated, advantageously ethoxylated, more especially primary alcohols preferably containing 8 to 18 carbon atoms and, on average, 1 to 12 moles of ethylene oxide (EO) per mole of alcohol, in which the alcohol radical may be linear or, preferably, methyl-branched in the 2-position or may contain linear and methyl-branched radicals in the form of the mixtures typically present in oxoalcohol radicals. However, alcohol ethoxylates containing linear radicals of alcohols of native origin with 12 to 18 carbon atoms, for example coconut 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_~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_~$ 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, 5 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.
Suitable other nonionic surfactants are alkyl glycosides with the general formula RO(G)X where R is a primary, linear or methyl-branched, more particularly 2-methyl-branched, aliphatic radical containing 8 to 22 10 and preferably 12 to 18 carbon atoms and G stands for a glycose unit containing 5 or 6 carbon atoms, preferably glucose. The degree of oligomerization x, which indicates the distribution of monoglycosides and oligoglycosides, is a number of 1 to 10 and preferably 1.2 to 1.4.
Another class of preferred nonionic surfactants which may be used 15 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 20 or which are preferably produced by the process described in International patent application WO-A-90113533.
Nonionic surfactants of the amine oxide type, for example N-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-C O-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 xylose. The N-alkoxy- or N-aryloxy-substituted compounds may then be converted into the required polyhydroxyfatty acid amides by reaction with fatty acid methyl esters in the presence of an alkoxide as catalyst, for example in accordance with the teaching of International patent application WO-A-95!07331.

According to the invention, preferred washing processes are characterized in that the detergent tablets used contain anionic and nonionic surfactant(s). Performance-related advantages can arise out of certain quantity ratios in which the individual classes of surfactants are used. Particularly preferred washing processes are characterized in that the detergent tablets contain anionic and/or nonionic surfactants) and have total surfactant contents above 2.5% by weight, preferably above 5%
by weight and more preferably above 10% by weight, based on the weight of the tablet.
For example, in particularly preferred washing processes, the ratio of anionic surfactants) to nonionic surfactants) in the tablets used is from 10:1 to 1:10, preferably from 7.5:1 to 1:5 and more preferably from 5:1 to 1:2. In other preferred washing processes, the detergent tablets contain surfactant(s), preferably anionic andlor nonionic surfactants, in quantities of 5 to 40% by weight, preferably 7.5 to 35% by weight, more preferably 10 to 30% by weight and most preferably 12.5 to 25% by weight, based on tablet weight.
It can be of advantage from the performance point of view if certain classes of surfactants are missing from certain phases of the detergent tablets or from the entire tablet, i.e. from every phase. In another important embodiment of the present invention, therefore, at least one phase of the tablets used in the washing process is free from nonionic surfactants.
Conversely, a positive effect can also be obtained through the presence of certain surfactants in individual phases or in the tablet as a whole, i.e. in every phase. Introducing the alkyl polyglycosides described above has proved to be of particular advantage, so that washing processes in which at least one phase of the tablets used contains alkyl polyglycosides are preferred.
As with the nonionic surfactants, the omission of anionic surfactants from individual phases or from all phases can result in detergent tablets which are more suitable for certain applications. Accordingly, washing processes using detergent tablets where at least one phase of the tablet is free from anionic surfactants are also possible in accordance with the present invention.
The detergent tablets used in the washing process according to the invention may also contain a so-called "disintegrator". In order to facilitate the disintegration of heavily compacted tablets, disintegration aids, so-called tablet disintegrators, may be incorporated in them to shorten their disintegration times. 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 provide for 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. Swelling dis-integration aids 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.
Detergent tablets preferably used in the washing process according to the invention additionally contain 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 3 to 7%
by weight and more preferably 4 to 6% by weight, based on the weight of the tablet.
According to the invention, preferred disintegrators are cellulose-based disintegrators, so that preferred detergent tablets contain a cellulose-based disintegrator in quantities of 0.5 to 10% by weight, preferably 3 to 7% by weight and more preferably 4 to 6% by weight. Pure cellulose has the formal empirical composition (C6H~o05)" and, formally, is a ~i-1,4-polyacetal of cellobiose which, in turn, is made up of two molecules of glucose. Suitable celluloses consist of ca. 500 to 5000 glucose units and, accordingly, have average molecular weights of 50,000 to 500,000.
According to the invention, cellulose derivatives obtainable from cellulose by polymer-analog reactions may also be used as cellulose-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. The cellulose derivatives mentioned are preferably not used on their own, but rather in the form of a mixture with cellulose as cellulose-based disintegrators. The content of cellulose derivatives in mixtures such as these is preferably below 50% by weight and more preferably below 20% by weight, based on the cellulose-based disintegrator. In one particularly preferred embodiment, pure cellulose free from cellulose derivatives is used as the cellulose-based disintegrator.
The cellulose used as disintegration aid is preferably not used in fine-particle form, but is converted into a coarser form, for example by granulation or compacting, before it is added to and mixed with the premixes to be tabletted. Detergent tablets which contain granular or optionally co-granulated disintegrators are described in German patent applications DE 197 09 991 (Stefan Herzog) and DE 197 10 254 (Henkel) and in International patent application WO-A-98140463 (Henkel). Further particulars of the production of granulated, compacted or co-granulated cellulose disintegrators can also be found in these patent applications. The particle sizes of such disintegration aids is mostly above 200 Nm, at least 90% by weight of the particles being between 300 and 1600 Nm in size and, more particularly, between 400 and 1200 pm in size. According to the 5 invention, the above-described relatively coarse-particle cellulose-based disintegrators described in detail in the cited patent applications are preferably used as disintegration aids and are commercially obtainable, for example under the name of Arbocel~ TF-30-HG from Rettenmaier.
Microcrystalline cellulose may be used as another cellulose-based 10 disintegration aid or as part of such a component. This microcrystalline cellulose is obtained by partial hydrolysis of the celluloses under conditions which only attack and completely dissolve the amorphous regions (ca. 30%
of the total cellulose mass) of the celluloses, but leave the crystalline regions (ca. 70%) undamaged. Subsequent de-aggregation of the 15 microfine celluloses formed by hydrolysis provides the microcrystalline celluloses which have primary particle sizes of ca. 5 Nm and which can be compacted, for example, to granules with a mean particle size of 200 Nm.
In many cases, so-called "effervescent systems" are also used as disintegration-promoting systems in detergent tablets. Oligomeric 20 oligocarboxylic acids, such as succinic acid, malefic acid and above all citric acid, in combination with carbonates or hydrogen carbonates are normally used in effervescent systems. In preferred embodiments of the present invention, however, the detergent tablet used is not an "effervescent tablet", i.e. preferred detergent tablets are free from oligomeric 25 oligocarboxylic acids, more particularly citric acid.
Besides the ingredients mentioned (bleaching agent, bleach activator, builder, surfactant and disintegration aid), the detergent tablets used in the washing process according to the invention may contain other typical detergent ingredients from the group of dyes, perfumes, optical brighteners enzymes, foam inhibitors, silicone oils, redeposition inhibitors, discoloration inhibitors, dye transfer inhibitors and corrosion inhibitors.

In preferred washing processes, the detergent tablets additionally contain one or more substances from the group of bleach activators, enzymes, pH regulators, perfumes, perfume carriers, fluorescers, dyes,s foam inhibitors, silicone oils, redepositioo inhibitors, optical brighteners, discoloration inhibitors, dye transfer inhibitors and corrosion inhibitors.
Suitable enzymes are, in particular, those from the classes of hydrolases, such as proteases, esterases, lipases or lipolytic enzymes, amylases, cellulases or other glycosyl hydrolases and mixtures thereof. All these hydrolases contribute to the removal of stains, such as protein-containing, fat-containing or starch-containing stains, and discoloration in the washing process. Cellulases and other glycosyl hydrolases can contribute towards color retention and towards increasing fabric softness by removing pilling and microfibrils. Oxidoreductases may also be used for bleaching and for inhibiting dye transfer. Enzymes obtained from bacterial strains or fungi, such as Bacillus subtilis, Bacillus licheniformis, Streptomyces griseus, Coprinus cinereus and Humicola insolens and from genetically modified variants are particularly suitable. Proteases of the subtilisin type are preferably used, proteases obtained from Bacillus lentus being particularly preferred. Of particular interest in this regard are enzyme mixtures, for example of protease and amylase or protease and lipase or lipolytic enzymes or protease and cellulase or of cellulase and lipase or lipolytic enzymes or of protease, amylase and lipase or lipolytic enzymes or protease, lipase or lipolytic enzymes and cellulase, but especially protease-andlor lipase-containing mixtures or mixtures with lipolytic enzymes.
Examples of such lipolytic enzymes are the known cutinases. Peroxidases or oxidases have also been successfully used in some cases. Suitable amylases include in particular a-amylases, isoamylases, pullanases and pectinases. Preferred cellulases are cellobiohydrolases, endoglucanases and ~-glucosidases, which are also known as cellobiases, and mixtures thereof. Since the various cellulase types differ in their CMCase and avicelase activities, the desired activities can be established by mixing the cellulases in the appropriate ratios.
The enzymes may be adsorbed to supports andlor encapsulated in membrane materials to protect them against premature decomposition.
The percentage content of the enzymes, enzyme mixtures or enzyme granules may be, for example, from about 0.1 to 5% by weight and is preferably from 0.5 to about 4.5% by weight.
In addition, the detergent tablets used in the washing process 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 andlor terephthalic acid known from the prior art or derivatives thereof, more particularly polymers of ethylene terephthalates and/or polyethylene glycol terephthalates or anionically andlor nonionically modified derivatives thereof. Of these, the sulfonated derivatives of phthalic acid and terephthalic acid polymers are particularly preferred.
The tablets may contain derivatives of diaminostilbenedisulfonic acid or alkali metal salts thereof as optical brighteners. Suitable optical brighteners are, for example, salts of 4,4'-bis-(2-anilino-4-morpholino-1,3,5-triazinyl-6-amino)-stilbene-2,2'-disulfonic acid or compounds of similar composition which contain a diethanolamino group, a methylamino group, an anilino group or a 2-methoxyethylamino group instead of the morpholino group. Brighteners of the substituted 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 perfumes are added to the detergent tablets used in the washing process 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, citronellyloxyacetaldehyde, 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 used in the washing process 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 detergent tablets to be used in the washing process 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 cyclodextrin/perfume 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.
It has been found that detergent tablets having a high specific gravity can be used with advantage in the washing process according to the invention. According to the invention, washing processes in which the detergent tablets have a density above 1000 gcm3, preferably above 1050 gcm3 and more preferably above 1100 gcm3 are preferred.
The process according to the invention comprises the washing of laundry in a normal domestic washing machine using a detergent tablet which is introduced into the washing drum without a dispensing aid. The consumer may decide how the tablet (or tablets where several tablets are to be used) should be placed in the drum. Thus, the laundry may be loaded into the machine first followed by addition of the detergent tablets) which islare placed in or on the laundry. A washing process in which the detergent tablets are placed in or on the laundry loaded into the drum before the washing process represents a preferred embodiment of the present invention.

The detergent tablets may of course also be introduced into the drum first and the laundry subsequently loaded into the washing machine.
A washing process in which the detergent tablets are introduced into the drum and the laundry is placed on the tablets before the washing process 5 is another preferred embodiment of the present invention.
In order not to restrict the consumer in regard to the potential uses of the tablets placed at his disposal, it is preferred to achieve high performance levels even in applications which are not covered by the recommended dosages. If conventional detergent tablets which can only 10 be dispensed from dispensers are introduced into the dispensing compartment by the consumer, the poor dispensing behavior and the poor washing result attributable to the lack of detergent can frustrate the consumer. In a preferred embodiment of the present invention, therefore, the detergent tablets are designed to be dispensed without leaving any 15 residues, even when dispensed from a dispensing compartment, so that the detergent is available to the washing process. Accordingly, a preferred washing process according to the invention is characterized in that the detergent tablets can be dispensed without leaving any residues, even from dispensing compartments.
20 In the context of the present invention, the expression "without leaving any residues" means that at most 5% by weight of the quantity of detergent originally dispensed is present in the dispensing compartment after the dispensing process, the quantity left in the compartment being weighed out after drying.
25 Embodiments of the invention are described in the following examples which are not to be construed as limiting.
Examples To produce detergent tablets containing sodium percarbonate, surfactant granules were mixed with other detergent ingredients and the 30 resulting mixture was tabletted (tablet diameter 44 mm, tablet height 22 mm, tablet weight 37.5 g). The composition of the surfactant granules are shown in Table 1 below while the composition of the premix to be tabletted (and hence the composition of the tablets) is shown in Table 2.
Table 1:
Surfactant granules [% by weight]
C9_~3 alkyl benzenesulfonate 18.4 C~2_~8 fatty alcohol sulfate 4.9 C~2_~8 fatty alcohol ~ 7 EO 4.9 Soap 1.6 Sodium carbonate 18.8 Sodium silicate 5.5 Zeolite A (water-free active substance)31.3 Optical brightener 0.3 Na hydroxyethane-1,1-diphosphonate0.8 Acrylic acid/maleic acid copolymer5.5 Water, salts Balance Table 2:
Premix [% by weight]
Surfactant granules 60.0 Sodium perborate monohydrate19.0 Tetraacetyl ethylenediamine 7.0 Foam inhibitor 3.5 Enzymes 2.5 Perfume 0.5 Zeolite A 1.0 Cellulose 5.5 For disintegration trials, two tablets were tested in various washing machines. To this end, each machine was loaded with 3.5 kg of laundry, two tablets were placed in the laundry and a 40°C colors program was started without any prewash. Commercially available tablets which, according to the dosage instructions, had to be dispensed via the drum using a net dispenser, were used for comparison. These comparison tablets contained sodium perborate as their bleaching agent and were added without dispensers similarly to the washing process according to the invention. On completion of the wash program, the residues left on the rubber collar of the washing machine were visually evaluated.
Discoloration of the laundry was also evaluated, the following scheme being used for both evaluations:
++ no residues on the collarlno discoloration + slight residues on the collarlslight lightening of black fabrics - distinct residues on the collarlvisible discoloration of colored fabrics -- large residues (tablet remains) on the collarldistinct discoloration of colored laundry.
The results of the two washing processes in various machines are set out in Table 3:
Table 3:
Washing processes (comparison) Machine type Invention Comparison Residue DiscolorationResidueDiscoloration Whirlpool AWG 780 ++ ++ _ _ Siemens Siwamat plus ++ ++ - _ Matura ~5kostar 9150 ++ + _ _ AEG ~5ko-Lavamat 6955 ++ + __ _ Bauknecht WA 2381 ++ ++ _ _ Miele W 918 ++ ++ + -

Claims (26)

1. A process for washing laundry using detergent tablets in a domestic washing machine, wherein the detergent tablets are added to the laundry in the drum without a dispensing aid before the washing process and contain sodium percarbonate.

2. A washing process as claimed in claim 1, wherein the detergent tablets contain sodium percarbonate in quantities of 1 to 40% by weight based on tablet weight.

3. A washing process as claimed in claim 2, wherein the detergent tablets contain sodium percarbonate in quantities of 5 to 30% by weight based on tablet weight.

4. A washing process as claimed in claim 3, wherein the detergent tablets contain sodium percarbonate in quantities of 10 to 25% by weight based on tablet weight.

5. A washing process as claimed in any one of claims 1 to 4, wherein at least 60% by weight of the sodium percarbonate particles present in the detergent tablets have a particle size below 0.8 mm.

6. A washing process as claimed in claim 5, wherein at least 70% by weight of the sodium percarbonate particles present in the detergent tablets have a particle size below 0.8 mm.

7. A washing process as claimed in claim 6, wherein at least 80% by weight of the sodium percarbonate particles present in the detergent tablets have a particle size below 0.8 mm.

8. A washing process as claimed in claim 7, wherein at least 90% by weight of the sodium percarbonate particles present in the detergent tablets have a particle size below 0.8 mm.

9. A washing process as claimed in any one of claims 5 to 8, wherein the sodium carbonate is substantially free from particles larger than 1.2 mm in size.

10. A washing process as claimed in any one of claims 1 to 9, wherein the detergent tablets contain surfactant(s) in quantities of 5 to 40% by weight based on tablet weight.

11. A washing process as claimed in claim 10, wherein the detergent tablets contain surfactant(s) in quantities of 7.5 to 35% by weight based on tablet weight.

12. A washing process as claimed in claim 11, wherein the detergent tablets contain surfactant(s) in quantities of 10 to 30% by weight based on tablet weight.

13. A washing process as claimed in claim 10, wherein the detergent tablets contain surfactant(s) in quantities of 12.5 to 25% by weight based on tablet weight.

14. A washing process as claimed in any one of claims 9 to 13, wherein the surfactant(s) are selected from anionic and/or nonionic surfactants.

15. A washing process as claimed in any one of claims 1 to 14, wherein the detergent tablets additionally contain a disintegration aid in quantities of 0.5 to 10% by weight.

16. A washing process as claimed in claim 15, wherein the disintegration aid is present in quantities of 3 to 7% by weight.

17. A washing process as claimed in claim 16, wherein the disintegration aid is present in quantities of 4 to 6% by weight.

18. A washing process as claimed in any one of claims 15 to 17, wherein said disintegration aid is cellulose-based.

19. A washing process as claimed in claim 18, wherein the disintegration aid is in granular, cogranulated or compacted form.

20. A washing process as claimed in any one of claims 1 to 19, wherein the detergent tablets have a density above 1000 gcm3.

21. A washing process as claimed in claim 20, wherein the detergent tablets have a density above 1050 gcm3.

22. A washing process as claimed in claim 21, wherein the detergent tablets have a density above 1100 gcm3.

23. A washing process as claimed in any one of claims 1 to 22, wherein the detergent tablets additionally contain one or more substances selected from the group consisting of bleach activators, enzymes, pH regulators, perfumes, perfume carriers, fluorescers, dyes, foam inhibitors, silicone oils, redeposition inhibitors, optical brighteners, discoloration inhibitors, dye transfer inhibitors and corrosion inhibitors.

24. A washing process as claimed in any one of claims 1 to 23, wherein the detergent tablets are placed on or in the laundry loaded into the drum before the washing process.

25. A washing process as claimed in any one of claims 1 to 23, wherein the detergent tablets are added to the drum and the laundry is placed on the tablets before the washing process.

26. A washing process as claimed in any of claims 1 to 5, wherein the detergent tablets are also designed to be dispensed from the dispensing compartment without leaving any residues.