DK159555B - DISHWASH WITH THIXOTROP PROPERTIES, PROCEDURE FOR PREPARING THEREOF AND USING THEREOF. - Google Patents

Description

DK 159555 B

The invention relates to dishwashing detergents for automatic washing with thi-xotropic properties and improved chemical and physical stability which are readily dispersible in the washing medium to provide efficient cleaning of service, glassware, porcelain and the like.

The invention also relates to methods of preparing the agent and its use.

10 Commercially available dishwashing detergents for household dishwashers present in powder liners have several drawbacks, e.g. non-uniform composition; costly work processes necessary for their manufacture; tendency to clump upon storage at high humidity, resulting in the formation of clumps which are difficult to disperse; dusting, which is a source of particular irritation to users suffering from allergies and tends to clump in the dishwasher dispenser. Furthermore, liquid forms of such agents generally cannot be used in automatic dishwashers 20 due to high foams, unacceptably low viscosities and extremely high alkalinity.

Recent research and development activity has gathered on the gel or "thixotropic" form of such agents, e.g. abrasive cleansers and automatic dishwashing products with the character of thixotropic pastes. Detergents thus provided are, first of all, unfortunate in that they are insufficiently viscous to remain "retained" in the dispenser of the dishwasher and additionally provide stain-like residues on service, glassware, crockery and the like. Thixotropic cleansers should preferably be high viscous in a calm state, Bingham plastic by nature and have relatively high flow points. However, when subjected to shear stresses, such as by shaking in a container or pressing through an orifice, they must quickly become fluid and upon cessation of the applied shear stress quickly return to the high viscous / Bingham plastic state. Stability is also of great importance, ie there should not be 2

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some clear sign of phase separation or leakage after long standing.

The preparation of gel detergents for automatic dishwashers and with the previously described properties has so far proved problematic, especially with regard to agents for use in household dishwashers. For effective use, it is generally recommended that the automatic dishwashing detergent, hereinafter also referred to as ADD, contain (1) sodium tri-polyphosphate (NaTPP) to soften or bind minerals in hard water and to emulsify and / or peptize contamination; (2) sodium silicate to impart the necessary alkalinity for effective cleaning and to provide protection for fine porcelain glaze and decoration; (3) sodium carbonate, which is usually considered optional, to improve the alkalinity; (4) a chlorine release agent to aid in the removal of contaminant staining leading to water stains; and (5) a foaming agent / surfactant to reduce foam thereby improving machine efficiency and achieving necessary cleaning performance. See, e.g. SDA Detergents in Depth, "Formulation Aspects of Machine Dishwashing", Thomas Oberle (1974). Detergents that approximate the previously described agent are mostly liquids or powders. The combination of such ingredients in a gel form effective for use in home appliances has proved difficult. Usually, such agents omit hypochlorite bleach, as this tends to react with other chemically active ingredients, especially surfactant, thereby degrading the suspending or thixotropic agent and reducing its effectiveness. In U.S. Pat.

30,115,308 disclose thixotropic pastes for automatic washing containing a suspending agent, e.g. CMC, synthetic clays or 1 in yeast; inorganic salts including silicates, phosphates, polyphosphates, etc., a small amount of surfactant, and an antifoaming agent. Bleaching is not described. U.S. Patent No. 4,147,650 is somewhat reminiscent of this, possibly including a C1 bleach, but no organic surfactant or antifoaming agent. Pro- 3

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the product is further described as a detergent slurry with no apparent thixotropic properties.

U.S. Patent No. 3,985,668 describes sieve abrasive cleaners of gel-like consistency containing (1) a suspending agent, preferably of the smectite or attapulgitler species; (2) an abrasive, e.g. silica sand or perlite; and (3) a filler comprising low density powdered polymers, expanded pearlite and the like having a flowability 10 and thus stabilizing effect on the agent in addition to serving as a volume absorbing agent, thereby replacing water which would otherwise be available to form an undesirable upper swimming layer due to leakage and phase destabilization.

The above are the essential constituents. Optional ingredients include hypochlorite bleach, bleach stable surfactant and buffer, e.g. silicates, carbonates, monophosphates, etc. Builders such as NaTPP may be incorporated as an additional optional agent to provide or supplement the builder function not provided by the buffer, the amount of such builder not exceeding 5% of the total agent of invention. Maintaining the desired pH values> 10 is made possible by the buffer / builder components. A high pH is said to minimize degradation of chlorine bleach and undesirable reaction between surfactant and bleach. When present, NaTPP is limited to 5%, as indicated. A foaming agent is not disclosed.

Thus, it is a primary object of the invention to provide a detergent having thixotropic properties which is advantageously suitable for use in an automatic dishwasher and does not suffer from one or more of the above disadvantages.

A further advantage of the invention is to provide such an agent of good physical stability, without significant phase separation appearing after standing for extended periods.

in

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Another advantage of the invention is to provide such an agent in which problems associated with undesirable reaction between chemically active ingredients are removed or at least substantially reduced.

5

A further advantage of the invention is the provision of such an agent of the aforementioned stability under the highly alkaline conditions necessary for effective performance of the detergent.

10

Another advantage of the invention is to provide such an agent with improved rheological properties which exhibits higher viscosities at low shear rates and lower viscosities at high shear rates - and thus advantageously is intended for use in dispensers of automatic dishwashers.

A further advantage of the invention is to provide such a agent with low foaming properties and improved cleanability which is readily dispersible in the dishwasher.

Other advantages of the invention will become apparent from the following description.

The above object is achieved by an aqueous thixotropic detergent for automatic dishwashers containing by weight: (a) 8 to 35% alkali metal tripolyphosphate; (b) 2.5 to 20% sodium silicate; (C) 0 to 9% alkali metal carbonate; (d) 0.1 to 5% chlorine bleach stable, water dispersible organic detergent; (e) foam breaker; (f) chlorine-containing detergent compound; and (g) thixotropic thickener in a sufficient amount to give the agent a thixotropy index of about 2.5 to 10, which detergent is characterized by alkali metal tri-5

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the polyphosphate (a) has an average degree of hydration of less than 1 or more than 5, that the antifoam (s) is stable to chlorine bleaches and is contained in an amount of 0 to 5%, and that the 5 chlorine-containing bleaching compound (f) is present in an amount providing 0.2 to 4% of available chlorine.

Thus, compound ADDs are low-foaming; stable, both chemically and physically, are readily soluble in the washing medium and most effective at pH values that best contribute to improved purification effect, namely pH 10.5-13.5. The agents usually have gel consistency, ie. a high-viscous, opaque gel-like material of Bingham plastic nature and thus relatively high utilization rates. Therefore, a certain shear force is required to initiate or increase flow which would be obtained in the triggered moving dispenser of an automatic dishwasher. Under such conditions, the agent is rapidly liquidized and readily distributed. If the shear force is interrupted, the liquid agent quickly returns to a high viscosity, Bingham plastic state, which closely approximates its previous consistency.

Processes for preparing the agent are characterized by the characterizing parts of claims 8 and 9.

25

In general, the ADD efficiency is directly linked to (a) available chlorine levels; (b) alkalinity; (c) solubility in a washing medium; and (d) foaming. It is preferred herein that the pH of the ADD be at least about 9.5, preferably from 10.5 to 13.5 and most preferably at least approx. 11.5. At low pH, the ADD product is for viscous, ie. approximately solid-like and therefore cannot be readily liquefied at the shear force levels appearing in the distributor vessel under normal machine operating conditions. Actually, the agent loses a lot of 35, if not all, of its thixotropic character. Thus, the addition of NaOH is often necessary to increase the pH value so that it. is within the aforementioned ranges and flowability 6

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creators. The presence of carbonate is also often necessary herein as it acts as a buffer which enables the maintenance of the required pH value. However, excess carbonate must be avoided as it may cause the formation of needle-like carbonate crystals and thereby impair the stability, thixotropy and / or purity of the ADD product. Caustic soda (NaOH) serves the additional function of neutralizing the phosphorus or phosphonic acid ester foam degrading agent when present. Ca. 0.5 to 3% by weight NaOH and approx. Typically, 2 to 9% by weight of sodium carbonate in the agent is 10, although it should be noted that sufficient alkalinity can be provided with NaTPP and sodium silicate.

NaTPP used in the agent in an amount of from approx. 8 to 35% by weight, preferably approx. 20 to 30% by weight, should preferably be 15 free of heavy metals which tend to degrade or inactivate the preferred sodium hypochlorite and other chlorine-containing bleaching compounds. In order to improve and accelerate the hydration of the solubilization of NaTPP and to avoid excessive thickening of the agent, NaTPP may have an average degree of hydration of less than ca. 1 or more than approx. 5, i.e. 0 to 27% by weight or at least 16.5% by weight of water including the stable hexahydrate having a hydration degree of 6 corresponding to approx. 18% by weight water or more. A wetting to an average value of approx. Indeed, 0.3 to 1% water is very effective as it serves to form the germ of the stable hexahydrate, which accelerates hydration and solubilization of the remaining NaTPP particles.

Foam inhibition is important to increase the efficiency of the dishwasher and to minimize the destabilizing effects that may occur due to the presence of excess foam in the washing machine during use. Foam can be sufficiently reduced by appropriate selection of the type and / or amount of the detergent-active material, the essential foam-forming component. The degree of foaming is also somewhat dependent on the hardness of the wash water in the machine, whereby appropriate adjustment of the NaTPP amounts having a water softening effect can help to provide 7

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bring about the desired degree of foam inhibition. However, it is usually preferred to incorporate a chlorine bleaching stable foam exchanger or inhibitor. Particularly effective are the alkylphosphonic esters of formula 50

II

HO - P - R

OR

10 which e.g. can be obtained from BASF-Wyandotte (PCUK-PAE) and in particular the alkyl acid phosphate esters of formula 0

II

HO - P - OR

15 I

OR

that e.g. can be obtained from Hooker (SAP) and Knapsack (LPKn-158), one or both R groups of each ester type independently of each other being Ci2-20 ~ a ^ ky1 · Mixtures of the two types, or any other chlorine bleaching stable types or mixtures of mono- and di-esters of the same type may be used. Particularly preferred is a mixture of mono and di-C 1-6 alkyl alkyl phosphate esters such as monostearyl / distearyl acid phosphates 25 1.2 / 1 (Knapsack). When used, amounts of 0.1 to 5% by weight, preferably approx. Typically, 0.1 to 0.5% by weight of the foam degrading agent in the composition, the weight ratio of the detergent component (d) to the foam degrading agent (s) usually being in the range of approx. 10: 1 to 1: 1 and preferably approx. 4: 1 to 1: 1. Other anti-foaming agents include, e.g. the known silicones, etc.

Although any chlorine-containing bleaching compound may be used in the agents of the invention, such as dichloroisocyanurate, dichlorodimethylhydantoin, chlorinated TSP and the like, alkali metal hypochlorite, e.g. potassium, lithium, magnesium and especially sodium hypochlorite. The remedy must contain 8

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(I.e., sufficient chlorine-containing bleaching compound to obtain) approx. 0.2 to 4% by weight of available chlorine, determined, for example, by acidification of 100 parts of the agent with an excess of hydrochloric acid. A solution containing approx. 0.2 to 4% by weight of sodium-5 hypochlorite contains or provides approximately the same percentage of available chlorine. Ca. 0.8 to 1.6% by weight of available chlorine is particularly preferred.

The sodium silicate, which provides the alkalinity and protection of hard surfaces, such as fine porcelain glaze and decoration, is used in an amount of from approx. 2.5 to 20% by weight, preferably approx. 5 to 15% by weight, in the agent. The sodium silicate is usually added in the form of an aqueous solution, preferably with a Na 2 O: SiO 1: 2.2 to 1: 2.8. It should be mentioned here that the major part of the other components of this agent, especially NaOH, sodium hypochlorite, foam degrading agent and thixotropic thickening agent, are also often added in the form of a previously prepared aqueous dispersion or solution.

The detergent active material required herein should be stable in the presence of chlorine bleach, especially hypochlorite bleach, and preferably comprise the organic anionic, amine oxide, phosphine oxide, sulfoxide and betaine water dispersible surfactant types, the former being preferred. They are used in 25 quantities ranging from approx. 0.1 to 5%, preferably approx. 0.3 to 0.8%. Particularly preferred surfactants herein are the commercially available straight-chain or branched-chain alkali metal mono- and / or di-C8-14 alkyldiphenyloxide mono- and / or disulfonates, e.g. "DOWFAX" 3B-2 and "DOWFAX" 2A-1. Generally, the paraffin sulfonates tend to impair, if not destroy, the thixotropic properties, as they have been shown to increase viscosity too much, causing severe shear force problems. In addition, the surfactant must be compatible with the other ingredients of the detergent.

Other suitable surfactants include primary alkyl sulfates, alkyl sulfonates, alkylarylsulfonates and sec-alkyl sulfates. Examples of this are sodium Cig-ie "" alkyl sulfates, such as

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g as sodium dodecyl sulfate and sodium tallow alcohol sulfate, sodium <10-18 alkanesulfonates such as sodium hexadecyl-1-sulfonate, and sodium C12 -188 alkylbenzenesulionates such as sodium dodecylbenzenesulfonates. The corresponding potassium salts may also be used.

As other suitable surfactants or detergents, the amine oxide surfactants typically have the formula F is methyl, and R 1 is a long chain alkyl group having from 8 to 22 carbon atoms, e.g. a lauryl, myristyl, palmityl or cetyl group. Instead of an amine oxide, a corresponding surfactant phosphine oxide RgR2 PO or sulfoxide RR150 can be used. Betaine surfactants typically have the formula R2R + N + R "C00" wherein each R is a lower alkylene group having from 1 to 5 carbon atoms. Specific examples of these surfactants are lauryl dimethyl amine oxide, myristyldimethyl amine oxide, coconut dimethyl amine oxide, cured tallow dimethyl amino. corresponding phosphine oxides and sulfoxides, and the corresponding betaines including dodecyl di methyl ammonium acetate, tetradecyldiethyl ammonium pentanoate, hexadecyldimethylammonium hexanoate and the like. For biodegradability, the alkyl groups in these surfactants should be linear and preferred.

Surfactants of the aforementioned type are known and are e.g. U.S. Patent Nos. 3,985,668 and 4,271,030.

Thixotropic thickeners, i.e. thickeners or suspending agents imparting thixotropic properties to an aqueous medium are known and may be organic or inorganic, water soluble, water dispersible or colloid forming and monomeric or polymeric and must of course be stable in these agents, e.g. stable to high alkalinity and chlorine bleach compounds such as sodium hypochlorite. Particularly preferred are generally the inorganic colloid-forming clays of · smectite and / or attapulgite type. These materials are used •

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10 usually in amounts of approx. 2 to 5% by weight, but in each case in sufficient quantity to impart the desired thixotropic properties and Bingham plasticity.

Smectite species include montmorillonite (bentonite), hectolitre, saponite and the like. Materials of this type are available under the trademarks such as "Thixogel" # 1 and "Gelwhite" GR from the Georgia Kaolin Company (both of which are montmorillonites). At-tabulite grids include materials commercially available under the trademarks "Attagel", i.e. "Attagel" "40," Attagel "50 and" Attagel "150 from Engelhard Minerals and Chemicals Corporation. Mixtures of the smectite and attapulgi types in weight ratios of 4: 1 to 1: 5 are also suitable for this purpose. Thickeners or suspending agents of the aforementioned kind are known. also, being described in, for example, U.S. Patent No. 3,985,668. Abrasive or polishing agents should be avoided.

The amount of water contained in these agents must, of course, not be so high as to give an disadvantageously low viscosity and flowability, or so low as to give disadvantageously high viscosity and low flowability, with the thixotropic properties in each case. diminished or destroyed. Such an amount can be readily determined by routine tests in each case, usually in the range of from 45 to about 25% by weight, preferably about 55 to 65% by weight. The water should also preferably be deionized or softened.

The ADD product of the invention exhibits improved rheological properties assessed by testing product viscosity 30 as a function of shear rate. The study confirms that the agents exhibit higher viscosity at a low shear rate and lower viscosity at a high shear rate, the data indicating effective fluidization and gelling within the shear rates occurring in the dishwasher. In practice, this means improved pouring and processing characteristics as well as less leakage in the dispenser compartment of the machine compared to currently used 11

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liquid or gel-like ADD products. At the shear rates used, corresponding to 3 to 30 rpm. per minute, the viscosity (Brookfield) of approx. 15.00Ό-30,000 cps. to approx. 3000-5000 cps., Measured at room temperature using a LTV Brookfield viscometer after 3 minutes using a No. 4 spindle. A shear rate of 7.4 seconds is equivalent to the rotation of one spindle per second. minute of approx. Third

An increase of approx. ten times the shear rate gives a 6- to 7-fold reduction in viscosity. With the currently used 10 ADD gels, the corresponding reduction in viscosity is only approx. doubled. With such agents, the initial viscosity, taken at ca. 3 rpm minute, moreover only approx. Thus, the agents in question exhibit threshold fluidizations at low shear rates and significantly greater in terms of incrementally increasing shear rate toward stepwise decrease in viscosity. This property of the immediate-acting ADD products is summarized in a thixotropy index (TI), which measures the ratio of (a) apparent viscosity at 3 rpm. and (b) apparent viscosity at 30 rpm. minute. The agents in question have a TI of 2.5 to 10 and preferably 6 to 8. Each of the tested ADD agents showed substantial and rapid return to previous condition when the shear force was interrupted.

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According to a preferred method of preparing these agents, all the inorganic salts must be dissolved or dispersed, i.e. carbonates (when used), silicates and tripolyphosphates, in the aqueous medium. The thickener is added at last. The foaming agent (when used) is initially provided as an aqueous dispersion, as is the thickener. The foaming dispersion, caustic soda (when used), and inorganic salts are first mixed at elevated temperatures in aqueous solution (deionized water) and then cooled, using stirring constantly. Bleach, surfactant and thickener dispersion at room temperature are then added to the cooled 12

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(25-30 ° C) solution. Apart from the chlorine bleaching compound, the total salt concentration (NaTPP, sodium silicate and carbonate) in the agent is usually about 20 to 50% by weight, preferably approx. 30 to 40% by weight.

5

Other conventional constituents may be included in these agents in small amounts, usually less than ca. 3% by weight such as perfume, hydrotropic agents such as sodium benzene, toluene, xylene and cumene sulfonates, preservatives, dyes and 10 pigments and the like, all of course being stable to chlorine bleach compounds and high alkalinity (properties of all the components). For dyeing, especially chlorinated phthalocyanines and aluminum silicate polysulfides are preferred which provide pleasant green and blue coloration, respectively. TiO 2 can be used to create whiteness or neutralize wrong shades.

The liquid ADD agents of the invention are readily used in known manner for washing dishes, other kitchen utensils and the like in an automatic dishwasher equipped with a suitable detergent dispenser in an aqueous washing bath containing an effective amount of the agent.

Example 1 25

A first dispersion of an antifoaming agent comprising a 2µl mixture of mono- and di- (C1-6 Cl8) a ^ y ^ esters phosphoric acid *, 0.16 g of 6 water is prepared by mixing at 60 ° C for 30 minutes using a plate-shaped stirrer. This dispersion is referred to as Part 1.

A first dispersion of "Gelwhite" GP (hydration), 3 g of thickener in 17 g of water, is prepared mixing at 70 ° C for 10 minutes using a Z-shaped stirrer mixer. This dispersion is referred to as Part 2.

The following ingredients are mixed in a Giusti mixer at 50-60 ° C: 13

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% ai ^ D

Deionized water 16.9

Part I 6.16 0.16

Caustic soda solution 40% NaOH 2.40 1.2 5 Sodium carbonate 7.00 7.0

Sodium silicate, 47.5% solution! 13.74 6.5

Sodium TPP (essentially water free) © 12.00 11.54

Sodium TPP (hexahydrate) 12.00 9.36 10

The mixture is cooled to 25-30 ° C with continuous stirring, and the following ingredients are added at room temperature:

_% _ ai ^ D

Sodium Hypochlori Top Solution - 13% Available Chlorine 7.615 1.0

Part II (dispersed with high speed turbine) 20.00 3.0 "Dowfax" 3B-β) 0.80 0.36 20 1. Knapsack LPKn 158 2. Active Ingredient 3. Na20: SiO2 - ΐΛ, 4 4. ie. 0-5%, especially 3%, moisture 25 5. 45% Na monodecyl / didecyldiphenyloxide disulfonates, aqueous solution.

An opaque agent (about 40% AI) with a gel-like consistency is obtained. The agent is determined to have a TI of approx. 7 at 30 the procedure described above based on apparent viscosity values of 28,000 cps. and 4,000 cps. at 3 rpm, respectively. per minute and 30 rpm. minute. When tested in an automatic dishwasher equipped with a dispenser compartment, the aforementioned agent exhibits an excellent cleaning effect and is dispensed easily and quickly. The agent is found to be satisfactory non-foaming. Little or no phase separation is observed after prolonged standing in a closed container

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holder. The pH of the agent, measured as a 1% solution in water, is 11.6. When performing the shear test assessments, it is noted that the agent quickly returns to its former consistency, suggesting no appreciable decrease of flow-5 point when tested within the limits previously described herein, i.e. within shear force limit values that at least approximate those found in an activated automatic dishwasher. No noticeable difference is obtained when dispensing the ADD product by means of a clamping tube instead of a dispenser compartment.

Example 2

Example 1, illustrating a total polyphosphate carbonate silicate concentration of approx. 37% is repeated, but the total concentration of such salts is varied within the limits given previously. The best results are obtained at a combined salt concentration of at least 30%, and especially when the sodium tripolyphosphate concentration is at least approx. 20%. Higher 20 silicate concentrations desirable to protect porcelain glaze and decoration also provide greater alkalinity which can be compensated for by appropriately reducing the caustic soda concentration and / or adjusting the sodium carbonate (buffer) concentration. As a result, the agent appears to be very sensitive to changes in NaTPP concentration (the higher concentration level is more effective) as well as its degree of hydration. Surfactant concentration variations generally require similar and direct variations in antifoam concentration 30 to achieve the desired low foaming levels.

Lowering the pH of the agent in Example 1 to below 10.5 results in a noticeable decrease in the efficiency of the agent as well as a corresponding decrease in the flowability.

35 15

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Example 3

Similar results are obtained when the procedure of Example 1 is repeated, but by replacing corresponding constituents with surfactant alkyl sulfate, e.g. sodium coconut alkyl sulfate, attapulgitles, e.g. "Attagel" 50, and a 2: 1 mixture of montmorillonite and "Attagel" 50. Addition of small amounts, e.g., 0.002-0.05% chlorinated phthalocyanine and aluminum silicate dyes to the agent of Example 1 (including 10 the first thickener dispersion or added to the cooled solution later.) Gives pleasantly colored - green and blue means, respectively.

Example 4 15 In this example, the ingredients are added to the mixing vessel with stirring in order of the order listed below in the order of homogeneity: 20 Parts (weight)

Deionized water 39,436 2% green color solution 0.173 "Attagel" 50 clay thickener® 3,375

Titanium Dioxide - Anatase 0.375 NasTPP - 0.5% Moisture (% total) 11,558 Knapsack LPKnl58® 0.160 13% Sodium Hypochlorite Solution 9,230

Sodium Carbonate 3,000 47.5% Sodium Si 1 Solution Solution 17,895 30 49% Sodium Hydroxide Solution 2,600

NasTPP - 0.5% moisture 11,558 "Dowfax" 3B-2 © 0.800 35

Claims (10)

1. Aqueous thixotropic dishwashing detergent for automatic dishwashers containing by weight (a) 8 to 35 g of 1kali metal tripolyphosphate, 30 (b) 2.5 to 20% sodium silicate, (c) 0 to 9% alkali metal carbonate, (d) 0.1 to 5 % chlorine bleaching stable, water dispersible organic detergent, (e) antifoaming agent, (f) chlorine-containing compound, and (g) thixotropic thickener in an amount sufficient to give the agent a thixotropy index as defined in DK 159555 B. 2.5 to 10, characterized in that the alkali metal tripolyphosphate (a) has an average degree of hydration of less than 1 or more than 5, 5 that the antifoam agent (s) is stable to chlorine bleaching agents and is contained in an amount of 0 to 5%, and that the chlorine-containing bleaching compound (f) is present in an amount which provides 0.2 to 4% of available chlorine. 1. Attapulgit An agent according to claim 1, characterized in that the detergent active material is selected from organic anionic, amine oxide, phosphine oxide, sulfoxide and betaine surfactants and any mixtures thereof. 3. An agent according to claim 1, characterized in that the detergent-active material is an alkali metal C8-14 alkyldiphenyl oxide sulfonate. 2. Foaming agent 3. Approx. 13% available chlorine An agent according to claims 1 to 3, characterized in that the chlorine-containing bleaching compound is sodium hypochlorite. 4. Na 2 O: SiO 2 - 1: 2.4 An agent according to claims 1-4, characterized in that the thickener is a smectite or attapulgitic species or a mixture thereof. 25 5. Detergent surfactant. The invention has been described with respect to preferred embodiments, and it should be understood that limitations and variations therein which are apparent to those skilled in the art must be included within the spirit and scope of the application and the scope of the appended claims. Claims. 25 -------------------- 5 Silicates 8.5% pH 12.8 +/- 0.3 Specific gravity 1.35 Min. Viscosity (Brookfield RVF, # 5 spindle, 20 rpm 10 rpm for 20 rev @ 25 ° C) 9,250 +/- 3,250 cps. An agent according to claims 1-5, characterized in that it contains approx. 0 to 9 wt% sodium carbonate. An agent according to claims 1-6, characterized in that it contains at least approx. 0.1% by weight of said antifoam agent selected from alkyl acid phosphate esters and alkyl phosphonic acid esters containing one or two C 1-2-20 alkyl groups and mixtures thereof. Process for the preparation of an agent according to claims 1-7, characterized in that in a first step it comprises preparing an aqueous dispersion of any component (s) used, mixing the dispersion with aqueous components. (a), (b) and any component (c) used, and then mixing the resulting mixture with components (d), (f) and a previously prepared aqueous dispersion of component (g). Process for the preparation of an agent according to claims 1-7, characterized in that it comprises admixing in water of sequentially components (g), half of component (a), any component (e), (f). , any component (c), (b), the other half of component (a), and to sit (d). Use of an agent according to any one of claims 1 to 7 for dishwashing in an automatic dishwasher. 15 20 25 30 35