CH655325A5 - WATER-BASED, THIXOTROPICAL DISHWASHER, IN PARTICULAR FOR AUTOMATIC DISHWASHER. - Google Patents

Description

The invention relates to a water-containing, thixotropic dishwashing detergent, in particular for automatic dishwashers, that is easily dispersible in the washing medium, so that dishes, glassware, porcelain and the like can be cleaned effectively.

Commercial detergents for household dishwashers are in powder form and have the disadvantage that they are composed unevenly, are relatively complex to produce, and tend to cake when stored in moisture, which leads to the formation of lumps that are difficult to disperse and dust in dry form and thereby cause particular irritation to consumers suffering from allergy and that they tend to clump together in the dispenser container of the dishwasher. Liquid dishwashing detergents, on the other hand, are difficult to use in automatic dishwashers because of the strong foam formation, the extremely low viscosity and the excessively high alkalinity of these detergents.

Recent research and development work has focused on gel or thixotropic mixtures, e.g. on abrasives and dishwashing detergents for automatic dishwashers in the form of thixotropic pastes. However, these products are unsuitable as dishwashing detergents primarily because they are not sufficiently viscous to remain “anchored” in the dispenser of the dishwasher, and moreover they remain on dishes, glassware, porcelain and the like. stained residue. Ideally, thixotropic cleaning agents should be highly viscous in the idle state or be in the plastic Bingham state and have relatively high flow values. Under shear stress, however, these products should quickly become liquid, for example when shaking in a container or being pressed through a nozzle, and if the applied shear force ceases, they should quickly return to Bingham in the highly viscous or plastic state. Furthermore, the stability of these products with regard to phase separation or exudation of components when standing for a long time is of considerable importance.

The detergents for automatic dishwashers with the properties mentioned above, which have hitherto been in gel form, present difficulties particularly in the case of the usual domestic dishwashers. It is generally recommended for such automatic dishwashing detergents that they use sodium tripolyphosphate (NaTPP) to soften the water or bind the water hardness salts and to emulsify and / or peptize dirt as well as sodium silicate to achieve the desired alkalinity for an effective one Cleaning and protection for the glaze and decor of porcelain and sodium carbonate, generally only optional, to increase the alkalinity, also a

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chlorine-releasing agent for the better removal of dirt stains or water stains and finally contain a foam pusher / surfactant in order to reduce foam formation and thus to support the effectiveness of the mechanical cleaning process and ultimately to give the required cleaning effect. This is described, for example, in “SDA Detergents in Depth, Formulations Aspects of Machine Dishwashing” by Thomas Oberle (1974). Detergents constructed in this way are mostly liquids or powders. The combination of these components in gel form, which are suitable for household dishwashers, has led to considerable difficulties. In general, the hypochlorite bleaching agent is omitted from these agents because it reacts with other chemically active ingredients and in particular with the surfactant, thereby decomposing the suspending agent or the thixotropic agent and impairing its effectiveness. For example, U.S. Patent 4,115,308 describes thixotropic pastes for automatic dishwashers containing a suspending agent, e.g. Carboxymethyl cellulose, synthetic clays and the like and further include inorganic salts such as silicates, phosphates, polyphosphates, etc., and small amounts of a surfactant and a foaming agent. However, a bleaching agent is not described. A similar product is known from US Pat. No. 4,147,650, which optionally contains hypochlorite, a bleaching agent, but no organic surfactant and no foam suppressant. The product is described as a detergent slurry that has no appreciable thixotropic properties.

From US Pat. No. 3,985,668, abrasives with a gel-like consistency are known which contain a suspending agent, preferably of the smectite and attapulgite type, furthermore abrasives, such as quartz sand or pearlite, and fillers, such as powdered low-density polymers or expanded pearlite, where these fillers show a certain buoyancy and thus stabilize the mixture and additionally act as dietary fiber and replace water, which would otherwise result in an undesirable protruding layer formation due to exudation or a phase impairment. In addition to these basic ingredients, such abrasives can optionally include hypochlorite bleach, bleach-stable surfactants and buffer substances, e.g. Silicates, carbonates, monophosphates, etc. contain. In addition, builders, such as NaTPP, can also be present in order to support the builder effect of the buffer substances. The amount of such builders should not exceed 5% by weight, based on the total composition. The buffer / builder components maintain the desired pH value above 10, the high pH value being intended to minimize decomposition of the chlorine bleach and an undesirable interaction between surfactant and bleach. The NaTPP which may be present is limited to 5% by weight: these products do not contain foam pressers.

The invention has for its object to provide a dishwashing detergent for automatic dishwashers, which has thixotropic properties and has improved chemical and physical stability and which can be easily and quickly dispersed in the washing liquid, so that the cleaning of porcelain, glass and dishes is carried out effectively can without any of the disadvantages described above.

It is also an object of the present invention to provide a dishwashing detergent with good physical stability which does not show any significant phase separation even after prolonged storage. Furthermore, the new dishwashing detergent should be constructed in such a way that no, or at least only significantly weakened, undesired interactions occur between the chemically active components.

Another object of the invention is to provide a dishwashing detergent for automatic dishwashers, which has the stability mentioned above even when the detergent is strongly alkaline, which is required for the effective cleaning power. Furthermore, the dishwashing detergent should have better rheological properties and have higher viscosities at low shear rates and lower viscosities at high shear rates, so that it can be used advantageously in the dispenser of the dishwashers. Finally, a dishwashing detergent is to be created with low foaming, improved cleaning power and faster dispersibility in a dishwasher.

This object is achieved according to the invention by a water-containing, thixotropic dishwashing detergent, in particular for automatic dishwashers, which is characterized by a content of 20 a) 8 to 35% by weight alkali metal tripolyphosphate,

b) 2.5 to 20% by weight of sodium silicate,

c) 0 to 9% by weight of water-soluble alkali metal carbonate,

d) 0.1 to 5% by weight of a water-dispersible,

organic surfactant resistant to chlorine bleach,

25 e) 0 to 5% by weight of a foam-inhibiting agent which is resistant to chlorine bleach,

f) chlorine bleach in an amount which provides 0.2 to 4% by weight of available chlorine, and g) a thixotropic thickener in an amount which is sufficient for the composition to have a thixotropic

Index from 2.5 to 10.

The dishwashing detergents according to the invention for automatic dishwashers have low foaming, are chemically and physically stable, dissolve quickly in the washing liquid and are particularly effective at pH values which result in an improved cleaning action, namely at pH values in the range of 10.5 to 13.5. The mixtures according to the invention normally have a gel-like consistency, i.e. they are strong ■ viscous, opaque, gelatinous products with a Bingham elasticity and therefore have relatively high flow values. Accordingly, a certain shear force is required in order to effect or intensify the outflow, as is the case in a dispenser of an automatic dishwasher which is operated or switched on. Under these conditions, the mixture according to the invention is quickly brought into a fluid state and easily released. When the shear force is removed, the fluid mixture quickly returns to its highly viscous state or 50 ° to the plastic Bingham state and almost returns to its previous consistency.

In general, the effectiveness of the dishwashing detergents according to the invention is directly dependent on the available chlorine content, the alkalinity, the solubility in the washing medium and the foam inhibition. The pH of the dishwashing detergents according to the invention is preferably at least about 9.5, particularly preferably in the range from 10.5 to 13.5 and very particularly preferably at least about 11.5. At relatively low pH values, the dishwashing detergent according to the invention is too viscous, i.e. almost solid, and can no longer easily be brought into a fluid state under the shear forces prevailing in the dispensing device: such an agent then loses most or even all of its thixotropic properties. The addition of NaOH is therefore often necessary in order to raise the pH to a value within the range given above and to improve the flow properties. The presence of carbonate is also often required

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lent, as it ensures that the desired pH range is maintained as a buffer substance. An excess of carbonate should be avoided, since otherwise needle-like carbonate crystals are formed which impair the stability, thixotropy and / or cleaning power of the dishwashing detergent according to the invention. Caustic soda (NaOH) also serves to neutralize the existing foam depressant, namely the phosphoric acid ester or phosphonic acid depressant. The dishwashing detergent according to the invention generally contains about 0.5 to 3% by weight NaOH and about 2 to 9% by weight sodium carbonate; however, it should be noted that sufficient alkalinity can also be ensured by the NaTPP and sodium silicate present .

The NaTPP present in the dishwashing detergent according to the invention in an amount in the range from about 8 to 35% by weight, preferably from about 20 to 30% by weight, should preferably be free of heavy metals, since these prefer to decompose or inactivate the To improve and accelerate the hydration and solubilization of NaTPP and to prevent unwanted thickening of the dishwashing detergent, the NaTPP can have an average degree of hydration of less than about 1 or more than 5, which means a water content of 0 to 2 , 7% by weight or at least 16.5% by weight, including the stable hexahydrate (degree of hydration of 6) corresponding to a water content of about 18% by weight or more 0.3 to 1 wt .-% water very effective and serves to form nuclei of the stable hexahydrate, which the hydration Promote and solubilize the remaining NaTPP particles.

Foam attenuation is important to increase the effectiveness of the dishwasher and to minimize the destabilizing effects that can occur due to excessive foaming during use. The foam can be reduced sufficiently by appropriately selecting both the type and the amount of the surfactants which are the main foam producing ingredient. The extent of the foam development also depends on the hardness of the washing water in the washing machine, whereby a suitable regulation of the proportions of NaTPP, which has a water softening effect, can help to achieve the desired degree of foam damping. In general, however, it is preferred to use a chlorine bleach foam suppressor or muffler. The alkylphosphonic esters of the formula are particularly effective here

0

II

HO - P - R

1

OR

e.g. are available from BASF-Wyandotte (PCUK-PAE), and in particular the alkyl phosphoric acid esters of the formula

0

II

HO - P - OR

1

OR

e.g. are available from Hooker (SAP) and Knapsack (LPKn-158), where one or both R groups in both types of esters independently represent alkyl groups with 12 to 20 C atoms. Mixtures of the two types of esters or other types resistant to chlorine bleaching agents or mixtures of mono- and diesters of the types mentioned can also be used. A mixture of mono- and di- (Ci6- to C! 8-alkyl) phosphoric acid esters is particularly preferred, for example the monosteraryl and distearyl phosphoric acid esters in a ratio of 1.2: 1 (product from Knapsack). As a rule, the foam presser is used in an amount of 0.1 to 5% by weight, preferably 0.1 to 0.5% by weight, in the dishwashing detergent according to the invention, the weight ratio of surfactant (Component d) to foam depressant (component e) is generally in the range from about 10: 1 to 1: 1, preferably in the range from 4: 1 to 1: 1. Other foam pushers include e.g. the well-known silicones.

Although any chlorine bleaching agent can be used in the dishwashing detergent according to the invention, e.g. Dichloroisocyanurate, dichlorodimethylhydantoin, chlorinated TSP u. the like, alkali metal hypochlorites such as e.g. Potassium, lithium, magnesium and especially sodium hypochlorite are preferred. The dishwashing detergents according to the invention contain such an amount of chlorine bleaching agent that is sufficient to supply 0.2 to 4% by weight of active chlorine, which can be determined, for example, by acidifying 100 parts of the dishwashing detergent with excess hydrochloric acid 2 to 4% by weight of sodium hypochlorite also provides or contains approximately the same percentage of active chlorine, with a content of 0.8 to 1.6% by weight of active chlorine being particularly preferred.

The sodium silicate, which contributes to the alkalinity and to the protection of hard surfaces, such as, for example, porcelain glazes and decorations, is used in an amount in the range from 2.5 to 20% by weight, preferably from 5 to 15% by weight. The sodium silicate is generally added in the form of an aqueous solution and preferably has a NaiO ^^ ratio of about 1: 2.2 to 1: 2.8, and most of the other constituents of the dishwashing detergent according to the invention , in particular sodium hydroxide, sodium hypochlorite, foam depressant and thixotropic thickener, are often used in the form of previously prepared aqueous dispersions or solutions.

The surfactants used in the dishwashing detergents according to the invention must be stable in the presence of chlorine bleaches, in particular hypochlorite bleaches, and are preferably organic anionic products, amine oxides, phosphine oxides, sulfoxides and betaines as water-dispersible types of surfactants, the former being particularly preferred. They are used in amounts of 0.1 to 5% by weight and preferably 0.3 to 0.8% by weight. Particularly preferred surfactants are linear or branched alkali metal mono- and / or -di-C8-CI4-alkyldiphenyloxide monosulfonates and / or disulfonates, for example the commercially available products Dowfax 3B-2 and Dowfax 2A-1. In general, paraffin sulfonates tend to adversely affect or destroy the thixotropic properties and have been found to cause excessive viscosity increases, causing serious difficulties in the high shear forces required. The surfactants should also be compatible with other components of the mixture according to the invention. Other suitable surfactants are, for example, primary alkyl sulfates, alkyl sulfonates. Alkaryl sulfonates and sec-alkyl sulfates such as sodium C 1 -C 8 alkyl sulfonates e.g. Sodium dodecyl sulfate, sodium tallow alcohol sulfate, sodium C CO-C |S alkane sulfonates, e.g. Sodium hexadecyl-1-sulfonate, as well as sodium C |; -C | 8-alkylbenzenesulfonates, e.g. Sodium dodecylbenzenesulfonate. The corresponding potassium salts can also be used.

Other suitable surfactants are amine oxides of the general

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bO

f> 5

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A formula RiR'NO, where each R radical is a lower alkyl radical, e.g. Is methyl, while R 'is a long-chain alkyl radical having 8 to 22 carbon atoms, e.g. a lauryl, myristyl, palmityl or cetyl group. Instead of an amine oxide, a corresponding phosphine oxide of the general formula R2R'PO or a sulfoxide RR'SO can also be used. Betaine-type surfactants have the general formula R2R'N + R "COO", where each R denotes a lower alkylene group having 1 to 5 carbon atoms. Suitable examples of these surfactants are lauryl dimethyl amine oxide, myristyl dimethyl amine oxide, coconut dimethyl amine oxide, hardened tallow dimethyl amine oxide and the corresponding phosphine oxides and sulfoxides and the corresponding betaines including dodecyl dimethyl ammonium acetate, tetradecyl diethylam monium pentanoate and hexadecyl hexanoate -dimethylammonium hexanoate u. Like. In view of the biodegradability, the alkyl radicals in these surfactants should be linear, so they are preferred.

Such surfactants are well known and e.g. in U.S. Patents 3,985,668 and 4,271,030.

Thioxotropic thickeners, i.e. Thickeners or suspending agents which impart thixotropic properties to an aqueous medium are already known and can be organic or inorganic water-soluble, water-dispersible and colloid-forming monomeric or polymeric products which are of course stable in the dishwashing detergents according to the invention, i.e. resistant to high alkalinity and chlorine bleaches, e.g. Sodium hypochlorite. The particularly preferred thickeners or suspending agents are generally inorganic colloid-forming clays of the smectite and / or attapulgite type. These substances are generally used in amounts of about 2 to 5% by weight, the amount being in any case sufficient to impart the desired Bingham plasticity to the product.

Smectittone include Montmorillonite (bentonite), hectorite, saponite u. The like. These products are sold under the trade names "Thixogel No. 1" and "Gelwhite GP" by the Georgia Kaolin Company and are Montmorillo-nite. The attapulgite clay from Engelhard Minerals and Chemicals Corporation can be used under the trade name "Attagel", such as "Attagel 40", "Attagel 50" and "Attagel 150". Mixtures of smectite and attapulgite in weight ratios of 4: 1 to 1: 5 are also suitable for this. Thickeners or suspending agents of the type mentioned above are well known and e.g. in U.S. Patent 3,985,668. Abrasives or polishing agents should be avoided.

The amount of water contained in the dishwashing detergents according to the invention should of course not be so high that the product obtains an excessively low viscosity and flowability, but also not so low that an excessively high viscosity and low flowability are produced, in any case the thixotropic properties adversely affected or even destroyed. The appropriate amount of water can easily be determined by routine experimentation in any particular case, and is generally in the range of about 45 to 75% by weight, preferably about 55 to 65% by weight. The water used is preferably deionized or plasticized.

The product according to the invention exhibits improved theological behavior, in particular with regard to the viscosity as a function of the shear forces. The studies confirm that the mixtures according to the invention have a higher viscosity at a low shear rate and a lower viscosity at a high shear rate, and the results indicate that an effective conversion to the fluid state and a more effective gelation in the shear forces which occur in dishwashers , is made possible. In practice, this means improved pouring and processing properties of the products obtained, which cannot undesirably emerge from the dispensing device, as is the case with conventional liquid dishwashing detergents.

With the shear forces occurring at 3 to 30 revolutions per minute, Brookfield viscosities in a range from 15000 to 30,000 10 ~ 3 Pa-s to about 3000 io to 5000 10 ~ 3 Pa-s are obtained, measured at room temperature with a LVZ Brookfield viscometer after 3 minutes with a No. 4 spindle. A shear rate of 7.4 s_1 corresponds to approximately 3 spindle revolutions per minute. An approximately 10-fold increase in the shear rate results in an approximately 6 to 7-fold reduction in viscosity. In the case of the known gel-type dishwashing detergents, the corresponding reduction in viscosity is only about two times the value. In addition, these known mixtures have an initial viscosity of only about 2500 to 2700 10 -3 Pa-s at about 3 revolutions per minute. The mixtures according to the invention show a threshold value of the fluidization at lower shear rates and to a significantly greater extent of the proportionate increase in the shear rate compared to the proportionate reduction in the viscosity. This property of the products according to the invention is expressed by the thixotropy index (TI), which corresponds to the ratio of the actual viscosity at 3 revolutions per minute to the actual viscosity at 30 revolutions per minute. The 30 mixtures according to the invention have a TI value of about 2.5 to 10 and preferably 6 to 8. All of the dishwashing detergents according to the invention which were tested showed a complete and rapid return to their former resting state with a corresponding consistency when no more shear forces were exerted. 35 were practiced.

According to a preferred process for producing the dishwashing detergents according to the invention, all inorganic salts, i.e. Carbonate (if present), silicate and tripolyphosphate, dissolved or dispersed in the aqueous medium 40. The thickener is usually added last. The foam presser (if present) is previously made as an aqueous dispersion, as is the thickener. The dispersion of the foam presser, the caustic soda (if present) and the inorganic salts 45 are first mixed at elevated temperatures in an aqueous medium (deionized water) and then cooled with constant stirring. Bleach, surfactant and thickener dispersion from room temperature are then added to the cooled (25 to 35 ° C) solution. Apart from the chlorine bleaching agent, the total salt concentration (NaTPP, sodium silicate and carbonate) in the mixture according to the invention is generally 20 to 50% by weight, preferably 30 to 40% by weight.

Other conventional ingredients can be incorporated into the dishes according to the invention in small amounts, generally less than 3% by weight, e.g. perfume, hydrotropic agents e.g. Sodium benzene sulfonate, sodium toluenesulfonate, sodium xylene sulfonate and sodium cumene sulfonate, also preservatives, coloring agents and pigments u. Like., Which of course must all be resistant to chlorine bleach and high alkalinity. The chlorinated phthanlo-cyanines and polysulfides of aluminosilicates, which give pleasing green or blue shades, are particularly preferably used for dyeing. Titanium dioxide 65 can be used to lighten or neutralize false colors.

The liquid dishwashing detergents according to the invention could be used for washing dishes or

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other kitchen appliances u. The like. In automatic dishwashers which are equipped with a suitable dispensing device for detergents, they can easily be used in effective amounts in a water-containing washing bath.

The invention is further illustrated by the following examples. All quantities are to be understood as weights, unless expressly stated otherwise.

example 1

A predispersion I was first prepared using a foam presser, which contains a 2: 1 mixture of mono- and di- (C | 6- to C | 8-) alkyl esters of phosphoric acid (LPKn 158 from Knappsack) in an amount of 0, Contained 16 g in 6 g of water, the dispersion being obtained by mixing for 30 minutes with a disc stirrer at 60 ° C.

Another predispersion II was prepared from a smectite (Gelwhite GP) in an amount of 3 g in 17 g of water, mixing for 10 minutes at a temperature of 70 ° C. with a Z-blade mixer.

The following ingredients were mixed in a Giusti mixer at 50 to 60 ° C:

Components

% By weight

% By weight

active ingredients deionized water

16.9

Dispersion I

6.16

0.16

NaOH solution (49%)

2.40

1.2

sodium

7.00

7.0

Sodium silicate solution (47%)

(Na20: Si02 = 1: 2.4)

NaTPP (anhydrous)

12.00

11.54

NatPP (hexahydrate)

12.00

9.36

The anhydrous NaTPP contained about 0-2.7 wt% moisture.

This mixture was cooled to 25-30 ° C. with constant stirring and then the following constituents were added at room temperature:

% By weight% active ingredients

Sodium hypochlorite solution with 13% by weight active chlorine 7.615 1.0

Dispersion II 20.00 3.0

Surfactant 0.80 3.36

A 45% aqueous solution of sodium monodecyl diphenyl oxide disulfonate and sodium didecyl diphenyl oxide disulfonate was used as the surfactant.

An opaque gel-like mixture with about 40% active ingredients was obtained, which had a TI value of about 7 or an actual viscosity of 28,000 10 -3 Pa-s at 3 revolutions per minute and 4,000 10 -3 Pa-s at 30 Revolutions per minute. When tested in an automatic dishwasher with dispenser, the mixture according to the invention showed excellent cleaning behavior, being dispensed easily and quickly. The dishwashing detergent according to the invention was satisfactorily non-foaming. After long storage of the product in a closed container, practically no or only insignificant phase separation was observed. The pH of the detergent in a 1% aqueous solution was 11.6. The behavior under

Shear conditions were excellent: after removal of the shear forces, the product quickly returned to the consistency of the previous rest state, which shows that the flow value is not appreciably adversely affected if the stresses are within the above-mentioned limit values of the shear force, which at least approximate those that occur in an automatic dishwasher that is switched on. There were also no discernible differences in the delivery of the product from a tube compared to the delivery from a dispenser of a dishwasher.

Example 2

Example 1, in which the action of a dishwashing detergent according to the invention with a combination of poly-phosphate, carbonate and silicate in a total concentration of about 37% was shown, was repeated with the difference that the total concentration of these salts was varied within the limits given above.

The best results have been obtained with a total concentration of these combined salts of at least 30% and in particular with a NaTPP concentration of at least about 20%. Higher silicate concentrations, which are desirable to protect the porcelain glaze and decor, also result in higher alkalinity, which can be compensated for by appropriately reducing the sodium hydroxide concentration and / or regulating the sodium carbonate concentration. The results show that these mixtures are very sensitive to changes in the NaTPP concentration (the higher concentration range is more effective) and the degree of hydrogenation. Changes in the surfactant concentration generally also require a corresponding and direct change in the concentration of the foam presser in order to achieve the desired low foaming.

A reduction in the pH of the mixture from Example 1 to below about 10.5 brings about a considerable decrease in the efficiency of this mixture and a corresponding decrease in the flowability.

Example 3

Similar results are obtained when the process according to Example 1 is repeated, with the difference that certain constituents are replaced by corresponding other constituents, namely the alkyl sulfate surfactant, e.g. by sodium cocoalkyl sulfate, and attapulgite clay, e.g. by Attagel 50 or by a mixture of Montmorillo-nit and Attagel 50 in a ratio of 2: 1. The addition of small amounts, e.g. 0.002 to 0.05% by weight of a chlorinated phthalocyanine and an aluminosilicate dye to the mixture according to Example 1 (including the predispersion of the thickener or the subsequent addition to the cooled solution) gives mixtures of a pleasant green or blue color .

Example 4

The following ingredients were added to a mixing kettle with stirring in the order in which the ingredients are listed below and mixed until homogenization was complete.

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Ingredients parts by weight of deionized water

39.436

green color solution (2%)

0.173

Attapulgite tone

3,375

Titanium dioxide

0.375

NaTPP, with 0.5% moisture

(half of the total)

11.558

Foam presser *

0.160

13% sodium hypochlorite solution

(with about 13% by weight of active chlorine)

9.230

sodium

3,000

47.5% sodium silicate solution

(with Na ^ OiSiO; = 1: 2.4)

17,895

49% sodium hydroxide solution

2,600

NaTPP with 0.5% moisture

11.558

Surfactant **

0.800

* 2: 1 mixture of mono- and di- (C | f) - to C | S-) alkyl esters of phosphoric acid.

** 45% aqueous solution of sodium monodecyl and sodium didecylphenyl oxide disulfonates.

Chemical and physical properties of the obtained

Mixture:

Total moisture content 59.8%

active chlorine 1.2 ± 0.1%

Silicates 8.5%

pH '12.8 ± 0.3

Density 1.35 min viscosity (Brookfield RVF viscometer, 9250 ± 3250 I0 "3

Spindle No. 5.20 rpm at 25 ° C) Pa-s

Claims (16)

655 325 1. Water-based, thixotropic dishwashing detergent, in particular for automatic dishwashers, characterized by a) 8 to 35% by weight alkali metal tripolyphosphate, b) 2.5 to 20% by weight of sodium silicate, c) 0 to 9% by weight of water-soluble alkali metal carbonate, d) 0.1 to 5% by weight of a water-dispersible, organic surfactant resistant to chlorine bleach, e) 0 to 5% by weight of a foam-inhibiting agent which is resistant to chlorine bleach, f) chlorine bleach in an amount that provides 0.2 to 4 weight percent available chlorine, and g) a thixotropic thickener in an amount sufficient that the composition has a thixotropy index of 2.5 to 10. 2. Dishwashing detergent according to claim 1, characterized in that the surfactant is an organic anionic product, an amine oxide, phosphine oxide, sulfoxide and / or betaine. 2nd PATENT CLAIMS 3. Dishwashing detergent according to claim 1, characterized in that the surfactant is an organic anionic alkali metal sulfate or sulfonate. 4. Dishwashing detergent according to claim 1, characterized in that the surfactant is an alkali metal (C8 to C14 alkyl) diphenyl oxide sulfonate. 5. Dishwashing detergent according to claim 1, characterized in that the chlorine bleach is sodium hypochlorite. 6. Dishwashing detergent according to claim 1, characterized in that the thickening agent is a smectite and / or attapulgite clay. 7. Dishwashing detergent according to claim 1, characterized in that it contains 0 to 9 wt .-% sodium carbonate. 8. Dishwashing detergent according to claim 1, characterized in that it contains at least 0.1 wt . 9. Dishwashing detergent according to claim 1, characterized in that the pH is 10.5 to 13.5. 10. Dishwashing detergent according to claim 1, characterized by a) 8 to 35% by weight of sodium tripolyphosphate, b) 2.5 to 20% by weight of sodium silicate, c) 2 to 9% by weight sodium carbonate, d) 0.1 to 5% by weight of a water-dispersible, organic surfactant resistant to chlorine bleach, e) 0 to 5% by weight of a foam-inhibiting agent resistant to chlorine bleach, 0 sodium hypochlorite in an amount sufficient to provide 0.2 to 2% by weight of available chlorine, g) 1.5 to 10% by weight of a thixotropic smectite and / or attapulgite clay as a thickener, which are sufficient for the composition to have a thixotropy index of 2.5 to 10, and h) sodium hydroxide in an amount which is sufficient that the composition has a pH of 10.5 to 13.5. 11. Dishwashing detergent according to claim 10, characterized in that it contains as a surfactant 0.5 to 2 wt .-% of a mixture of sodium salts of mono- and di- (CS to C 14 alkyl) diphenyloxysulfonic acids. 12. Dishwashing detergent according to claim 11, characterized in that it is a foam-inhibiting agent 0.1 to 0.5 wt .-% of a mixture of mono- and di- (Ci6- bis C 18 alkyl) contains phosphate esters. 13. Dishwashing detergent according to claim 12, characterized in that it contains 20 to 30 wt .-% sodium tripolyphosphate. 14. Dishwashing detergent according to claim 13, characterized in that it contains 2 to 5 wt .-% thixotropic montmorillonite clay as a thickener. 15. Dishwashing detergent according to claim 13, characterized in that it contains 2 to 5 wt .-% thixotropic attapulgite clay as a thickener. 16. Dishwashing detergent according to claim 13, characterized in that the thixotropy index has a value of 6 to 8.