DK167935B1 - TIXOTROPES, Aqueous Suspensions, and Procedures for the Purification of Soiled Objects WHEN USING IT - Google Patents

Description

in DK 167935 B1

The present invention relates to detergents for automatic washing with thixotropic properties, improved chemical and physical stability and with increased apparent viscosity, and which are readily dispersed in the washing medium to provide effective cleaning of service, cutlery, glass, porcelain and the like.

The invention also relates to a method for cleaning dirty objects, such as cutlery, glasses, kitchen utensils and similar service in an automatic dishwasher.

10

Commercially available household dishwashing detergents have several disadvantages, e.g. a non-uniform composition that expensive operations are necessary for their preparation tends to bake together at high humidity storage, resulting in the formation of lumps which are difficult to disperse, dustiness which is a source of particular irritation for users who suffer from allergies and tend to bake together in the dishwasher dispenser. However, liquid forms of such agents generally cannot be used in automatic dishwashers due to excessive foams, unacceptably low viscosities and excessive alkalinity.

Recent research and development activity has focused on the gel form or "thixotropic" form of such agents which are insufficiently viscous to remain "anchored" in the dispenser cup in the dishwasher, and furthermore stains residues on the washed articles, glass , porcelain and the like. Ideally, thixotropic cleansers should be very viscous in a calm state, be Bingham plastic in nature and have relatively high flow values. When subjected to shear forces, e.g. however, upon being shaken in a container or squeezed through an opening, they must quickly become fluid and upon cessation of the applied shear stress, they must quickly return to the high viscosity / Bingham plastic-to-35 state. Stability is also of primary importance, ie. there should be no significant sign of f aseadski Full view or leakage after prolonged delay.

Thus, the provision of automatic dishwashing agents in gel form having the aforementioned properties has proved problematic, especially with regard to means for use in household dishwashers. For effective use, it is generally recommended that the automatic dishwasher agent, hereinafter referred to as ADD, contains (1) sodium tripolyphosphate 5 (NaTPP) to soften or bind minerals in hard water, and to emulsify and / or peptize dirt, (2) sodium silicate to provide the alkalinity needed for effective cleaning and to provide protection for fine porcelain glaze and patterns, (3) sodium carbonate, generally considered optional, to increase alkalinity, (4) ) a chlorine releasing agent to aid in the elimination of dirt stains leading to water stains and (5) foam reducing / surfactant reducing foam, thereby increasing the effectiveness of the machine and providing the necessary cleaning power. See, e.g. SDA Detergents in Depth "Formulations

Aspects of Machine Dishwashing ", Thomas Oberle (1974). Cleaners approaching the aforementioned agents are mostly liquids or powders. Combining such ingredients in a gel form effective for domestic machine use has proved difficult. In general, such agents omit hypochlorite or otebium as it tends to react with other chemically active ingredients, especially surfactants, thereby degrading the suspending or thixotropic agent and damaging its effectiveness. No. 4,115,308 thixotropic pastes for automatic dishwashers containing a suspending agent such as CMC, synthetic clays or the like, inorganic salts containing silicates, phosphates and polyphosphates, a minor amount of surfactant and a foam suppressant.

30 *

Bleaches are not described. U.S. Patent No. 4,147,650 discloses something similar and optionally includes C1 (hypochlorite) bleach, but no organic surfactant or foam depressant. The product is further described as a detergent slurry without any particular thixotropic properties.

3 DK 167935 B1 US Patent No. 3,985,668 describes abrasive, abrasive cleaners of gel-like consistency containing (1) suspending agent, preferably Smecti tea type and atypical type, (2) abrasives, e.g. . silica sand or perlite 5 and (3) filler comprising low density powdered polymers, expanded perlite and the like having a buoyancy and thus stabilizing effect on the agent in addition to serving as a density filler, thereby replacing water otherwise available for undesirable supernatant ag formation resulting from 2o of leakage and phase destabilization. The foregoing are the essential constituents. Optional ingredients include hypochlorite bleach, bleach stable surfactant and buffer e.g. silicates, carbonates and monophosphates. Builders, such as NaTPP, may be included as additional optional components to provide or supplement builder function not provided by the buffer, the amount of the builder not exceeding 5% of the total agent of the patent. Maintaining the desired (greater than) pH levels of 10 is achieved with the buffer / builder components. A high pH is said to decrease the decomposition of the chlorine bleach and the undesirable interaction between surfactant and bleach. When NaTPP is present, it is limited to 5% as mentioned. No foam killer has been described.

In British Patent Applications Nos. GB 2,116,199A and GB 2,140,450A, liquid AOD agents are disclosed which have properties which desirably characterize a gel-type thixotropic structure containing each of the various constituents which are necessary for efficient cleaning in an automatic dishwasher. The usually gel-like aqueous dishwashing detergent for thixotropic automatic dishwashers comprises the following ingredients on a weight basis: (a) 5 to 35% a1ka1 in metal tripolyphosphate, (b) 2.5 to 20% sodium s (C) 0 to 9% alkali metal carbonate, (d) 0.1 to 5% chlorine bleach stable, water dispersible, organic, detergent, 5 (e) 0 to 5% chlorine bleach stable foam suppressant, (f) chlorine bleach compound in an amount which gives approx. 0.2 to 4 available chlorine; (g) thixotropic thickener in an amount sufficient to give the agent a thixotropic index of ca. 2.5 to 10 10 09 (h) sodium hydroxide if necessary to adjust the pH.

ADDs thus formulated are foamy, readily soluble in the washing medium and most effective at pH values which best lead to improved purity, namely pH 10.5-13.5. The agents are usually of gel consistency, ie. a high viscous opaque gel-like material with a Bingham plastic character and thus relatively high flow values. Thus, a certain shear force is required to initiate or increase flow, as would be achieved in the stirred dispenser cup in an activated automatic dishwasher. Under such conditions, the agent is rapidly fluidized and easily dispersed. When the shear force is interrupted, the liquid agent quickly returns to a high viscous Bingham plastic state, which is close to its previous consistency.

U.S. Patent No. 4,511,487 discloses a 1-foaming detergent paste for dishwashers. The patented thixotropic cleaner has a viscosity of at least 30 Pa.s at 20 ° C as determined with a rotational viscometer at a spindle speed 30 of 5 rpm. The agent is based on a mixture of finely divided hydrated sodium metas 1 in cat, an active chlorine compound and a thickening agent which is a leaf type hector silicate. Small amounts of nonionic surfactants and alkali metal carbonates and / or hydroxides can be used.

35

The formation of organol species by the interaction of clays (such as bentonite and hectorite) with organic compounds such as quaternary ammonium salts has also been described (W.S. Mardis, JAOCS, vol. 61, no. 2, page 382 (1984)).

While these previously described liquid ADD compositions c do not or only to a lesser extent have one or more of the above

ISLAND

As described above, it has been found that in practice further improvements in physical stability are required to increase the shelf life of the product, thereby increasing consumer acceptance.

In the above-mentioned Danish patent application No. 2708/86, the physical stability of clay-based, thixotropic liquid compositions is improved by the addition thereto of small amounts, e.g. from approx. 0.02 to 1% by weight of a polyvalent metal salt of a long chain fatty acid such as aluminum stearate.

15

While the combination of clay thickener and fatty acid salt stabilizer has been found to provide satisfactory long-term stability, such as the absence of phase separation for periods of up to 12 weeks and longer, the addition of clay to these formulations has several drawbacks.

When synthetic thickening agents are used, e.g. the order of addition of the various constituents and the control of the process conditions during the formulation of the agents critical to obtain the desired trixotropic and low foaming properties. In addition, the clay thickeners are expensive materials and can significantly contribute to the final product expense for the consumer. In some cases, the species thickening agents can actually interfere with the overall purification effect.

30

Thus, it is an object of the present invention to provide stable thixotropic aqueous suspensions avoiding the use of clay thickeners.

It is another object of the present invention to provide liquid ADD agents having thixotropic properties with improved physical stability and improved rheological properties.

6 DK 167935 B1

It is a further object of the present invention to provide thixotropic liquid ADD agents having reduced thixotropic thickeners without adversely affecting the generally high viscosities at low shear rates and lower viscosities at high shear rates characteristic of the desired thixotropic properties.

More broadly, it is an object of the present invention to provide stable aqueous thixotropic non-clay-based agents, especially liquid detergent pastes or gels for automatic dishwashers, by incorporating in the clay-free aqueous suspension a small amount of fatty acid effective to inhibiting the precipitation of the suspended particles and to counteract phase separation.

1 o

These and other objects of the present invention, which will become apparent from the following detailed description and preferred embodiments of the invention, are achieved by incorporating in aqueous liquid detergent a small but effective amount of a non-clay, non-polymeric, thixotropic agent. , which is a long-chain fatty acid. More particularly, in accordance with a preferred and specific embodiment of the invention, there is provided a normal gel-like automatic dishwasher cleaner incorporating from 0.03 to approx. 0.5% by weight of the agent of a long-chain fatty acid which is effective in inhibiting the precipitation of the suspended particles, such as alkali metal buffer salts, etc., without requiring any clay thickener, polymer or other thickening agent.

30 in accordance with this particular aspect, the present invention provides a normally gelatinous aqueous dishwashing detergent with thixotropic properties comprising: (a) 5 to 35% by weight alkali metal tripolyphosphate, 35 (b) 2.5 to 40% by weight sodium silicate, ( c) 0 to 9% by weight of alkali metal carbonate, (d) 0.1 to 5% by weight of chlorine bleaching agent 11, water dispersible, organic cleaning agent, (e) 0 to 5% by weight of chlorine bleaching agent, (f) chlorine bleaching compound in an amount to provide 0.2 to 4% by weight of available chlorine, 5 (g) 0 to 8% by weight of sodium hydroxide, which agent is appreciable in that it further contains (h) 0.03 to 0.5% by weight aliphatic fatty acid having from 8 to 22 carbon atoms, dimers thereof or trimers thereof, (i) the remainder being water.

10

Also related to this specific aspect, the invention provides a method for cleaning soiled articles, such as utensils, cutlery, glasses, kitchen utensils and the like, in an automatic dishwasher with an aqueous washing bath containing an effective amount of the liquid automatic dishwasher detergent ( According to this aspect of the invention, the LADD agent can be easily poured into the dispenser cup of the auto-dishwasher and will quickly thicken to its normal layered or paste-like state within a few seconds and remain safely inside. dispenser cup until shear forces are again applied thereto, such as by spraying water from the dishwasher.

The invention will now be described in more detail by means of specific embodiments thereof and by the following drawing, in which the figure is a graphical representation of ten-xotropic index for two different formulations according to the invention and a type-thickened liquid dishwashing detergent for automatic dishwashers. disclosed in GB Patent No. 302,140,450A.

The LADD products according to the descriptions of the aforementioned GB Patent No. 2,116,199A, GB Patent No. 2,140,450A and Danish Patent Application No. 2708/86 exhibit improved rheological properties judged by testing the viscosity of the product as a function of shear rate. The agents exhibited higher viscosity at a low shear rate and lower viscosity at a high shear rate, which data shows effective liquidity and gelation within the shear rates found in standard dishwashers. In practice, this means improved slope and improved machining properties, as well as less leakage in the dispenser cup of the machine compared to known liquid or gel ADD products. For applied shear rates equal to 3 to 30 rpm, we found the Brookfields similarities from approx. 10,000 to 30,000 cps to approx. 3,000 to 7,000 cps, measured at 10 room temperature using a LVT Brookfield, we are shuttered after 3 min using a spindle # 4. 3. An approximately two-fold increase in shear rate produces about a 3- to 9-fold reduction in viscosity, thus, the agents of the applicant's known invention exhibit threshold values for fluidity at lower shear rates and to a significantly greater extent expressed by incremental increases in shear rate. This property of the prior art LADD products is summarized as a thixotropic index (TI) which is the ratio of apparent viscosity at 3 rpm to 30 rpm. a TI from 2 to 10. The LADD-mi dls should exhibit substantial and rapid return to previous consistency in a calm state when displacement the force is interrupted.

While the determination of thixotropic index TI as a ratio of apparent viscosity at 3 and 30 rpm provides a satisfactory measure of product usability, further research and experience have shown that a more reliable measure of ten-xotropic index and product usability as a liquid ADD agent is obtained by determining thixotropy as a measure of the area of the hysteresis loop, which is obtained by recording under the conditions of shear force S described below, as a function of shear rate η when the shear rate is increased from 0 to a maximum value and then goes back to 0. The larger the area of the hysteresis loop, the larger the 9 DK 167935 B1 thixotropic index. In terms of apparent viscosity, it has also been found that as long as the viscosity at room temperature (22 ° ± 1 ° C) measured in Brookfield viscometer HATD using a spindle # 4 at 20 rpm is less than approx. 20,000 cps, the agent can be easily shaken so that a thixotropic agent can be readily "fluidized" or "liquefied" to allow the product to be dispensed through a conventional clamp tube or other suitable dispenser.

10

The present invention is based on the surprising finding that the same or improved rheological properties and physical stability, i.e. resistance to phase separation, precipitation, etc., as in the known liquid aqueous AODs, can be obtained at significantly lower cost and without any particular processing requirements by adding a small but effective amount of a long chain fatty acid to the thixotropic clay thickener, and when used, including the metal salt of the fatty acid. At the same time, improvements in staining and film formation ability (i.e. fewer stains and reduced film formation) can be achieved.

As an example of the improvement in rheological properties compared to a standard species thixotropic liquid ADD, reference is made to the accompanying drawing, which is a record of shear forces S, as a function of shear rate η for a clay-based LADD (3 wt% clay). ) (curve 1) and for two similar LADD agents in which the clay is replaced by 0.06% by weight of stearic acid (curve 2) or by 0.08% by weight of stearic acid (curve 3). Shear force S is measured in a static experiment using a Haake RV-3 machine equipped with a coaxial cup. The sample is placed in the outer cup and the inner cup is rotated by the machine at gradually higher shear rates to a maximum of 113 sec ~ 1, and then the shear rate is gradually reduced to zero. 35 The reaction is automatically absorbed as the shear force. The tests were performed using an MV II sensor system 10 (constant values A = 3.76 Pa, M = 0.9 sec "l). The area between the resulting curve lines for each sample is a measure of the thixotrope. pi, as larger areas indicate higher thixotropy, the flow point of each sample can also be determined from the curves shown in the figure; the floating point is the maximum force in the shear force versus shear velocity curve, while the physical stability is such that even after six For weeks or longer over temperature ranges ranging from near the freezing point to 40 ° C and more, the agents containing the fatty acid thickeners undergo no visible phase separation.

10

The preferred long chain fatty acids are the higher aliphatic fatty monocarboxylic acids having from 8 to. 22 carbon atoms, more preferably from 10 to 20 carbon atoms and particularly preferred from 12 to 18 carbon atoms, including the carbon atom of the fatty acid carboxyl group. Polycarboxylic acids may also be used. The aliphatic radical may be saturated or unsaturated and may be straight or branched. Straight-chain saturated fatty acids are preferred. Mixtures of fatty acids may be used, such as those obtained from natural sources, such as tallow fatty acid, coconut fatty acid, soy fatty acid, etc., or from synthetic sources available from industrial manufacturing processes.

Thus, examples of fatty acids which can be used as thickening agents in place of clay or polymeric thickening agents may include e.g. decanoic acid, lauric acid, dodecanoic acid, palmic acid, myristic acid, stearic acid, oleic acid, eicosanoic acid, tallow fatty acid, coconut fatty acid, soy fatty acid and mixtures of these acids. In addition, the dimers or trimers of these acids may also be used. Stearic acid and mixed fatty acids 30 e.g. coconut fatty acid is preferred.

Within the carbon chain length ranges of the monocarboxylic fatty acids listed herein, the viscosity of the product tends to decrease as the number of carbon atoms in the monocarboxylic fatty acid decreases. No systematic trends have been observed for the dimers or trimers or polyhydric carboxylic acids.

The amount of the fatty acid thickener to achieve the desired values of thixotropy and physical stability will depend on such factors as the nature of the fatty acid, the cleansing compound, inorganic salts, especially TPP, other LADD constituents as well as the expected storage conditions and shipping conditions.

S

However, in general, amounts of the thixotropic fatty acid agent in the range of 0.03 to 0.5%, preferably from 10.03 to 0.2%, especially preferably from 0.03 to 0.08%, provide the long-term stability and absence of phase separation upon standing or during transport at both low and elevated temperature necessary for a commercially acceptable product.

In general, the efficacy of the LADD agent is directly related to (a) the amount of chlorine available, (b) the alkalinity, (c) the solubility in the washing medium, and (d) the foam inhibition. It is preferred according to the invention that the pH value of the LADD agent be at least approx. 9.5 more preferably from 10.5 to 13.5 and most preferably at least approx. 11.5. At the relatively low pH values, the LADD products are too viscous, ie. as solids and therefore do not readily flow below the shear force levels created in the dispenser cup under normal operating conditions of the machine. The result is that the agent loses much if not all of its thixotropic character. Thus, addition of NaOH is often necessary to increase the pH to within the above ranges and to increase the flow properties. The presence of carbonate is also often necessary according to the invention as it acts as a buffer which helps maintain the desired pH level. However, too much carbonate must be avoided as it can cause the formation of needle-like crystals of carbonate, thereby damaging the stability, thixotropy and / or purity of the LADD product, as well as damaging the delivery ability of the product from e.g. terminal tube1 ash. Sodium hydroxide (NaOH) 35 further serves to neutralize the foam suppressing phosphorus or phosphonic acid ester when present.

12 DK 167935 B1

Ca. 0.5 to approx. 3% by weight NaOH and approx. 2 to approx. 9% by weight of sodium carbonate in the LADD agent is typical, although it should be noted that sufficient alkalinity can be provided with NaTPP and sodium il in cat.

5

NaTPP can be used in the LADD agent in an amount of from approx. 8 to approx. 35% by weight, preferably approx. 20 to approx. And should preferably be free of heavy metals which tend to decompose or inactivate the preferred sodium hypochlorite and other chlorine bleaching compounds. NaTTP may be anhydrous or hydrated, including the stable hexahydrate having a hydration degree of 6 corresponding to approx. 18% by weight water or more. In fact, for the stability of hexahydrate, the presence of some hydration seepage water is very effective in that it is thought to serve to form seed crystals of the stable he-l5 xahydrate which promotes hydration and solubilization of the other NaTPP particles. If only hexahydrate is used, the cleaning product may be too liquid and may have little to no thixotropic character. In contrast, if only the anhydrous NaTPP is used, the product may in some cases be too thick and therefore unsuitable. Particularly preferred LADD agents are obtained e.g. when using a weight ratio of 0.5: 1 to 2: 1 between anhydrous and hexahydrate in serified NaTPP and values of ca. 1: 1 is particularly preferred.

Foam inhibition is important to increase the efficiency of the dishwasher and to reduce 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 choice of the type and / or amount of purifying active material which is the most important foam producing component. The degree of foam also depends to some extent on the hardness of the wash water in the machine, whereby appropriate adjustment of the amounts of NaTPP having a water softening effect can help to provide the desired degree of foam inhibition. However, fo-22 is generally preferred to include a chlorine bleach stable foam suppressant or inhibitor. Particularly effective are the alkyl phosphonic acid esters of the formula DK 167935 ΒΊ 13 0

II

HO - P - R

OR

available from e.g. BASH-Wyandotte (PCUK-PAE) and in particular the alkyl acid phosphate esters of formula 0

II

HO - P - OR

OR

10 which can be obtained from e.g. Hooker (SAP) and Knapsack (LPKn-158), in which one or both R groups in each type of ester can independently represent a 0 ^ 2-20319ruPPe · Mixtures of the two types or any other chlorine. bleach stub 1 type or mixtures of mono and diesters 15 of the same type can be used. Particularly preferred is a mixture of mono- and di-Cjgg alkyl acid phosphate esters, such as monostearyl / distearlyl acid phosphates 1,2 / 1 (Knapsack). When used, amounts of 0.01 to 5 wt.%, Preferably 0.1 to 5 wt. 0.1 to approx. Typically, about 0.5% by weight of the foam suppressant agent typically comprises the weight ratio of the purifying active component (d) to the foam suppressant (s) generally from ca. 10: 1 to approx. 1: 1 and preferably from. ca. 4: 1 to approx. 1: 1. Other foam suppressants which may be used include e.g. the known silicones.

25

Although any bleaching chlorine compound can be used in the agents of the invention, such as dichloroisocyanurate, dichloro-dimethylhydantoin or chlorinated TSP, alkali metal hypochlorite is preferred, e.g. potassium, lithium, magnesium and especially 30 sodium hypochlorite or it. The agent should contain sufficient bleaching chlorine compound to provide 0.2 to 4.0% by weight of available chlorine, as determined e.g. by acidifying 100 parts of the agent with excess hydrochloric acid. A solution containing approx. 0.2 to approx. 4.0% by weight of sodium hypochlorite 35 contains or provides substantially the same percentage of available chlorine. Ca. 0.8 to approx. 1.6% by weight of chlorine is particularly preferred. Eg. advantageously, sodium hypochlorite (NaOCl) solution having from about ca. 11 to approx. 13% available chlorine in amounts of approx. 3 to approx. 20%, preferably from approx. 7 to approx. 12%.

5

The sodium sulphate, which provides alkalinity and protection of hard surfaces, such as fine porcelain glaze and pattern, is used in an amount ranging from approx. 2.5 to approx. 40% by weight, preferably approx. 10 to approx. 35% by weight of the agent. At the higher 10 amounts listed herein e.g. at quantities greater than approx.

10% by weight also gives the silicate increased anti-staining effect. The sodium silicate is usually added in the form of an aqueous solution, preferably having a Na 2 O: SiO 2 ratio of approx. 1: 2.2 to 1: 2.8 e.g. 1: 2.4. Most of the other constituents of the agent in particular NaOH, sodium hypochlorite and foam suppressant may also be added in the form of an aqueous dispersion or solution.

Purifying active material useful for the invention should be stable in the presence of chlorine bleach, especially hypochlorite bleach, and preferably comprise the water-dispersible surfactant types such as organic, anionic, amine oxide, phosphine oxide, sulphoxide, or betaine, the first mentioned anionic types. are most preferred. They are used in quantities ranging from approx. 0.1 to approx. 5% preferably from about 0.3 to approx. 2.0%.

Particularly preferred surfactants of the invention are the linear or branched alkali metal mono and / or di (C8-14) alkyl diphenyloxide mono and / or disulphates commercially available e.g. such as D0WFAX (registered trademark) 3B-2 and D0WFAX 2A-1. In general, the paraffin sulphonates t 1 - 30 are prone to damage, albeit not destroying, thixotropy, having been found to increase viscosity too much and cause severe shear force problems. In addition, the surfactant should be compatible with the other constituents of the agent. Other suitable surfactants include the primary alkyl sulfates, alkyl sulfonates, alkyl alkyl aryl sulfonates and secondary alkyl sulfates. Examples are sodium C 10-18 alkyl sulfates, such as sodium dodecyl sulfate and sodium tallow alcohol sulfate, sodium C 10-18 alpha sulfonates such as sodium hexadecylene sulfonate and sodium C 1-8 alkylene benzylbenzenesulfonate. benzenesulphonates. The corresponding potassium salts may also be used.

5

As other suitable surfactants or detergents, the surfactant amine oxide agent is typically the structure of R 1 R 2, where each R represents a lower alkyl group, e.g. represents 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 R 2 R 2 PO or sulfoxide R 11 50 may be used. Typically, surfactant betaine agents have the structure R2R * N - R "COO-f wherein each R represents a lower alkylene group having from 1 to 5 carbon atoms. Specific examples of these surfactants are lauryl dimethyl amine oxide, myri-dimethyl amine oxide, the corresponding phosphine oxides and sulfoxides and the corresponding betaines, including dodecyl dimethyl ammonium acetate, tetradecyldiethylammonium pentanoate, hexadecyl dimethyl ammonium hexanoate and the like. For biodegradability, the alkyl groups of these surfactants should be linear and such compounds preferred.

Surfactants of the type mentioned above, all well known in the art, are described e.g. in U.S. Patent Nos. 3,985,668 and 4,271,030.

The amount of water contained in these agents should, of course, not be so high as to give too low viscosity and flow unit, or so low as to give too high viscosity and low flowability, in both cases diminishing or destroying the thixotropic properties. Such an amount is readily determined by routine experimentation in a given case and is generally from ca. 25 to approx. 75% by weight, preferably approx. 55 to approx. 65% by weight.

The water should also preferably be deionized or softened. DK 167935 Pg 16

Other conventional constituents may be included in these agents in small amounts, which are generally less than about 10%. 3% by weight, such as perfume, hydrotropic agents such as sodium benzene sulfonate, toluene sulfonate, xylenesulfonate and cumene sulfonate, preservatives, dyes and pigments, and the like, all of which are stable to bleaching chlorine compounds and high alkalinity components ). Particularly preferred for staining are the chlorinated phthalocyanines and polyunsulfides of aluminum silicate which give a pleasant green and blue color respectively. TiO2 can be used for whitening or neutralizing impure color shades.

The liquid ADDs of the invention are readily used in known manner for dishwashing objects, such as cutlery, glass, ser vice and other kitchen utensils and the like in an automatic dishwasher equipped with a suitable detergent dispenser, in an aqueous wash bath containing an effective amount of the agent.

20

The invention can be practiced in various ways, and some specific embodiments are described to illustrate the invention with reference to the appended examples.

25 All quantities and proportions are by weight of the agent unless otherwise stated.

Example 1

To demonstrate the effect of the fatty acid thickener 30, liquid ADD compositions with varying amounts of thixotropic fatty acid thickener (Experiments 1, 2 and 3) are prepared, as shown in Table 1. A similar composition (Experiment # 4) corresponding to the composition of Example 1 of GB Patent No. 2,140,450A in accordance with the procedure described in said example.

17 DK 167935 B1 TABLE 1

Ingredients Attempt Attempt Attempt Attempt # 1 # 2 # 3 No. 4 5 Water 32.99 32.96 32.94 41.92

Stearic acid 0.03 0.03 0.08

Clay Art (Gel White GP) - - 3.00

Sodium acid in cat (47.5% solution of IO Na 2 O: SiO 2 in 1: 2: 4 ratio) 25.00 25.00 25.00 13.73

Sodium tri polyphosphate (substantially anhydrous ie about 3% moisture) 12.00 12.00 12.00 12.00 µ5 Sodium tripolyphosphate hexahydrate 12.00 12.00 12.00 12.00

Sodium carbonate (soda) 7.00 7.00 7.00 7.00

Sodium hypochlorite (13% available chlorine) 7.61 7.61 7.61 7.61 2o Surfactant (Dowfax 3B-2, 45% sodium mono- and di-decyl di-phenyl oxide di sulfonate aqueous solution) 0.80 0.80 0.80 0.80 Anti-foaming agent (Knapsack LPKn 158, and mixture of mono- and di-stearyl (C16_18) alkyl esters of phosphoric acid, mole ratio about 1: 1.3 0.16 0.16 0 , 16 0.16

Causal soda solution (50% NaOH) 2.40 2.40 2.40 2.40

Color (Graphitol Green) 0.01 0.01 0.01 0.01 35.00 100.00 100.00 100.00

A sample of each of the compositions of Experiments Nos. 2 and 3 and the Species-Based Comparative Composition (Experiment # 4) is subjected to shear force measurement using the Haake RV-3 machine, as described above for determination of thixotropic index and flow point. . The results are shown in the attached figure, where curve 1 is based on the sample from experiment no.

5 4, curve 2 is based on the sample from experiment # 2 and curve 3 is based on the sample from experiment # 3. The floating point value - the maximum value for shear force S, is shown in Table 2.

Other properties are also shown in Table 2 comprising the apparent viscosity rj, measured on a 24 hour sample using a Brookfield HATD viscometer using a spindle # 4 at 20 rpm (T = 22e ± leC ), density, capillary drainage rate, stability and centrifugation. Capillary drainage rate (CDR) is a measure of stability with higher values indicating higher stability. CDR measurements are performed by the following procedure: a No. 1 Whatman fi lter paper with a 6.4 cm diameter circle, then plotted, is placed on a 10 cm x 10 cm flat glass plate. A 6.4 cm long plastic tube with a 3.4 cm diameter diameter 20 is placed in a standing position, centered on the circle. The tube is filled with a sample of the liquid ADD (after standing for a day). Measure the time required for the solvent to leak out of the tube and reach the drawn circle. Time is measured on three sides of the circle and averages are calculated. Faster times mean that the gel does not hold the solvent (water) well, which can therefore seep into the filter paper. Times greater than approx. 7 min (all samples) are acceptable. The stability measurement is performed by placing the sample in a glass vial at room temperature and observing 2q% separation at the end of four weeks. The spin test is also a measure of stability. GI ascentri grout tubes are filled with equal volumes of each sample and centrifuged vertically, ie. in a plane parallel to the ground, in a Sorwall centrifuge for 25 min at 500 rpm. The volume of clear liquid is then measured. The results are given as the ratio of the height of clear liquid to the total height of the sample divided by 100, ie. . -a ^^ 1 a r x loo. Lower numbers of liquid height indicate greater stability.

DK 167935 E1 19 TABLE 2

Property Experiment Experiment Experiment Experiment No. 1 No. 2 No. 3 No. 3 5 Viscosity, cps 11,460 10,660 11,260 5,100 floating point, quilts / cm1 2 3 4 5 6 7 - 372 720 392 density, g / ml 1.35 1, 36 1.34 1.37 CDR (minutes) - 8.5 10.0 7.0 stability (4 weeks RT),% separation <1.0 0.0 0.0 5.0 centrifugation <1.0 0 , 0 0.0 5.0

The results in Table 2 clearly show the superior phase separation stability of stearic acid-based compositions 15 compared to the species-based composition. These results, together with the thixostropic characteristics illustrated by the graphical progression 11 in ng of the figure, show exterior 1 in greater superiority of the compositions of the invention with respect to dishwasher cup leakage.

20

Example 2

Each of the compositions of Experiments 1 to 4 of Example 1 is tested for comparability of purity (stain and film build on glass) using a Kenmore dishwasher 25 using tap water at a temperature of 54 ° C and 120

ppm in hardness. The test procedure is described in ASTM

D3566-79, except that only four cleaning cycles were used. The film formation and staining is judged on the following scale.

30

Film RatingIscale a

The best, no apparent movie.

2

Easier filming becomes visible.

3 35 3. Remarkable movie on the rise.

4

Continued increase of significant film.

5

Filmmaking is starting to get powerful.

6

Great filming, strong build.

7

Continued increase in heavy film.

20 DK 167935 B1 • Spot rating 1 sixths a A. The best - no spots B. Very few visible spots 5 C. Clear D. Significant coverage approx. 50%

The results are shown in Table 3.

TABLE 3 10

Trial No. Performance Assessment

Stain Film 1 B 1.2 2 B, C 1.2 15 3 B, C 2.3 4 C 2.3

Example 3

Similar results were obtained to those described above when stearic acid was replaced by isostearic acid, myristic acid, palmitic acid, lauric acid, emphol-dimeric acid, empfoltrimeric acid or emphol-1052 polyvalent acid.

In addition to the superior physical stability, thixotropy, and purification performance, the agents of the invention further have the significant advantage of requiring no particular order of addition of the respective constituents. All the ingredients can be added in any order or at the same time to a simple container, mixer, etc., and stirred until a uniform homogeneous mixture is reached. The mixture can be carried out at room temperature or at elevated temperature. It is not necessary to pre-mix some of the ingredients or to use shear mixing agents.

35

Claims (10)

21 DK 167935 B1 Aqueous, thixotropic, dishwasher detergent comprising: (a) 5 to 35 wt% alkali metal tripolyphosphate, (b) 2.5 to 40 wt% sodium silicate, (c) 0 to 9 wt% alkali metal carbonate, (d) 0 , 1 to 5 wt.% Chlorine bleach stable, water dispersible, organic, detergent, (e) 0 to 5 wt.% Chlorine bleach stable foam suppressant, (f) chlorine bleach compound in an amount to provide 0.2 to 4 wt.% Of available chlorine, (G) 0 to 8 wt% sodium hydroxide, characterized in that it further contains (h) 0.03 to 0.5 wt% aliphatic fatty acid having from 8 to 22 carbon atoms, its dimers or its trimers, (i) the remainder is water. An agent according to claim 1, characterized in that the aliphatic fatty acid (h) has from approx. 10 to approx. 22 carbon atoms. An agent according to claim 2, characterized in that the fatty acid has from approx. 12 to approx. 18 carbon atoms. Agent according to claim 1, characterized in that the fatty acid is stearic acid. An agent according to claim 1, characterized in that the fatty acid (h) is present in an amount of from approx. 0.03 to approx. 0.2%. 22 DK 167935 B1 6. An agent according to claim 4, characterized in that the fatty acid (h) is present in an amount of 0.03 to 0.08%. Agent according to Claim, characterized in that the chlorine bleach compound (f) is sodium hypochlorite. An agent according to claim 1 * characterized in that it contains at least 0.1% by weight of foam suppressant (s). An agent according to claim 8, characterized in that the foam suppressant is an alkyl acid phosphate ester or an alkyl phosphonic acid ester containing one or two 0 to 20-20 alkyl groups, or a mixture thereof. Agent according to claim. It is characterized in that it has a pH of 10.5 to 13.5. Oxygen Process for the cleaning of soiled articles, such as cutlery, glasses, kitchen utensils and similar service in an automatic dishwasher, characterized in that in an automatic dishwasher, the soiled articles come into contact with an aqueous washing bath in which an effective amount is dispersed. of the agent according to claim 1