FI91277C - Aqueous thixotropic automatic dishwasher detergent composition, its preparation method and a method for washing dishes - Google Patents

Description

91277 i

Aqueous thixotropic automatic dishwasher detergent composition, process for its preparation and method for washing dishes

The present invention relates to thixotropic aqueous suspensions having improved physical stability. Even more particularly, the invention relates to the use of long chain fatty acids as a thixotropic excipient in the formation of stable gel-like liquid suspensions suitable for use as a dishwasher detergent composition.

The present invention relates to an aqueous thixotropic automatic dishwasher detergent composition having improved chemical and physical stability and increased apparent viscosity, and which is readily dispersible in the detergent for efficient cleaning of dishes, glassware, porcelain and the like.

Commercial household dishwasher detergents, which are available in powder form, have several disadvantages, e.g. uneven composition. Expensive measures are required to manufacture them. They tend to agglomerate in storage at high moisture contents, resulting in the formation of lumps that are difficult to disperse. Dysfunction is a special source of irritation for users suffering from allergies. In addition, they tend to agglomerate in the dishwasher dispenser. However, liquid forms of such compositions cannot generally be used in dishwashers due to high foam contents, unusable low viscosities and very high alkalinity.

Recent research and development has focused on gel forms or "thixotropic" forms of such compositions, which are insufficiently viscous to remain in the cup of the washing machine dispenser and, in addition, leave the patchy residue in containers, glassware. Ideally, the thixotropic detergent compositions 2 should be highly viscous at rest, "Bingham plastics" in nature, and have a relatively high myotdval. However, when subjected to shear, such as shaking in a container or squeezing through the mouth, they should rapidly change to a high viscosity / Bingham plastic state. Likewise, persistence is of paramount importance, for example, there should be no visible signs of phase separation or leakage after a long standstill.

The production of compositions for use in a dishwasher in gel form with the properties described above has so far proved problematic, especially for household dishwashers. For efficient use, it is generally recommended that a dishwasher detergent, hereinafter referred to as APP, contain (1) sodium tripolyphosphate (NaTPF) to soften or bind hard water minerals and to emulsify and / or peptide dirt; (2) sodium ilicate to provide the necessary alkalinity to achieve an effective washing result and to protect fine porcelain glazing and patterns; (3) sodium carbonate, generally considered optional, to increase alkalinity; (4) a chlorine-releasing agent for eliminating water-staining dirt stains; and (5) antifoam / surfactant to avoid foaming, thereby increasing the efficiency of the machine and providing the necessary washing power. Detergents that roughly correspond to the compositions described above are mostly liquids or powders. The effective combination of such raw materials in gel form for the use of household appliances has proved difficult. Generally, such compositions avoid hypochlorite bleaching because it tends to react with other chemically active ingredients, especially the surfactant, thereby degrading the suspending or thixotropic agent and inhibiting its effective action. Thus, U.S. Patent 4,115,308 discloses a thixotropic dishwashing paste containing a synthetic clay or the like of a suspending agent, e.g., CMC; inorganic salts including silicates, phosphates and polyphosphates, a small amount of 91277 3 surfactants and a defoamer. Bleach is not included. U.S. Patent No. 4,147,650 is somewhat similar, optionally containing a Cl (hypochlorite) bleach, but no organic surfactant or antifoam. The product is described as an additional detergent mixture which does not have obvious thixotropic properties.

U.S. Patent No. 3,985,668 describes abrasive cleaners having a gel-like consistency and comprising (1) a suspending agent, preferably a clay of the smectite and atapulgite type, (2) an abrasive agent such as silica sand or perlite, and (3) ) as a filler for lightweight powdered polymers, expanded perlite and the like, which have a resilience and thus a stabilizing effect on the composition in addition to acting as a pulp agent, thus replacing water otherwise available due to the formation of an undesirable surface layer thanks to. The above ingredients are essential. Possible ingredients include a hypochlorite bleach, a bleach-resistant surfactant and a buffer, e.g. silicates, carbonates and monophosphates. Salt formers, such as NaTPF, may be further incorporated as possible ingredients to produce or increase the salt-forming ability not produced by the buffers, with the amount of such salt-forming agent remaining less than 5% of the total composition according to the patent. Maintaining the desired (above) pH 10 levels is accomplished with buffer / salt former components. The high pH is said to minimize the degradation of the chlorine bleach and the undesired interaction between the surfactant and the bleach. When present, NaTPF is limited to 5% as mentioned. Foam killer is not included.

GB Patent Applications 2,116,199A and 2,140,450A, both designated Colgate-Palmolive, contain liquid APP compositions, preferably with thixotropic, gel-like structure properties, each containing the various ingredients necessary for efficient dishwasher performance. point of view. Normally, a gel-like aqueous dishwasher detergent composition having thixotropic properties contains the following ingredients by weight: (a) 5-35% alkali metal tripolyphosphate; (b) 2.5-20% sodium silicate; (c) 0-9% alkali metal carbonate; (d) 0.1-5% chlorine bleach resistant water dispersible organic detergent; (e) 0-5% chlorine bleach resistant antifoam; (f) chlorine bleach in an amount of 0.2-4% free chlorine; (g) a thixotropic thickener in an amount sufficient to give the composition a thixotropic index of the order of 2.5 to 10; and (h) sodium hydroxide as needed to adjust the pH.

The APP compositions thus formulated are low-foaming, readily soluble in the washing liquid and at their most effective at the pH values which work best to achieve an improved washing operation, namely at pH 10.5-13.5. The compositions generally have a gel consistency, e.g., a highly viscous opal gel-like substance having the character of a Bingham plastic and thus relatively high yield values. As a result, a certain shear force is required to initiate or increase the flow that could be obtained in the moving dispensing cup of an energy-loaded dishwasher. Under such conditions, the composition liquefies rapidly and is easily dispersible.

When the shear force is cut off, the liquid composition rapidly changes to a high viscosity Bingham plastic state, closely resembling its previous composition.

U.S. Patent 4,511,487 describes a low foam dishwashing paste. The patented thixotropic cleaning agent has a viscosity of at least 30 Pa at 20 ° C as determined by a rotary viscometer at 5 rpm. The composition is based on a mixture of finely divided sodium metasilicate hydrate, an active chlorine compound and a precipitating aid, the latter being a strip-like silicate 91277 5 hectorite type. Small amounts of neutral surfactants and alkali metal carbonates and / or hydroxides may be used.

The formation of organic clays by the interaction of clays (such as bentonite and hectorite) with organic compounds such as quaternary ammonium salts has been described (W.S. Mardis, JAOCS, Vol. 61, No. 2, p. 328 (1984)).

Although the liquid APP formulations described above do not have more or only a few of the shortcomings described above, it has been found in actual use that further improvements are still needed to increase the physical stability of the product and thus the shelf life of the product.

According to U.S. Pat. No. 4,752,409, the physical stability of thixotropic liquid clay-based formula combinations is improved by adding a small amount, e.g. 0.02-1% by weight, of a polyvalent metal salt of a long chain fatty acid such as aluminum stearate.

When a combination of a clay precipitant and a fatty acid stabilizer has been found to have satisfactory long-term stability, such as avoiding phase separation for periods of 12 weeks or more, there are several disadvantages to adding clay to these formula combinations.

For example, when using a clay-like precipitant, the order in which the various ingredients are added and the review of process conditions during formulation are critical to achieving the desired thixotropic properties and low foaming tendencies. In addition, clay-like precipitants are expensive substances and can significantly increase the cost of the final product to the consumer. In some cases, clayey precipitants may in fact be a disadvantage in the overall performance of the cleaning.

Consequently, it is an object of the invention to provide permanent thixotropic aqueous suspensions for automatic dishwashers which have improved physical stability and rheological properties and which avoid the use of clayey precipitants.

Another object of the invention is to provide thixotropic liquid dishwashing detergent compositions having reduced levels of a thixotropic precipitant without adversely affecting high viscosities at low shear rates and low viscosities at high shear rates.

It is an object of Laajeinin's invention to provide a permanent aqueous thixotropic, non-clay-based composition for washing an automatic dishwasher, in particular by incorporating liquid detergent pastes or gels into the anhydrous aqueous suspension.

These and other objects of the invention, which will be better understood from the following detailed description of the invention and its preferred embodiments, are achieved by the inclusion in an aqueous washing liquid composition of a small but effective amount of a non-clay or polymeric long-term, thixotropic agent. such a dimer or trimer.

The fatty acid effectively prevents the settling of suspended particles, such as alkali metal former salts, etc., without the aid of any clay, polymer or other precipitants.

The usually gel-like aqueous automatic dishwasher detergent composition according to the invention, which has thixotropic properties, is thus characterized in that it contains by weight: 91277 7 (a) 5-35% of alkali metal tripolyphosphate; (b) 2.5-40% sodium silicate; (c) 0-9% alkali metal carbonate; (d) 0.1-5% of a water-dispersible organic detergent active agent resistant to chlorine bleaching; (e) 0-5% chlorine bleach resistant antifoam; (f) a chlorine bleach compound in an amount that produces about 0.2-4% available chlorine; (g) 0.03-0.5% aliphatic fatty acid having 8-22 carbon atoms, a dimer or trimer thereof, and (h) 0-8% sodium hydroxide; (i) the remainder of the composition being water

The invention also relates to a method for preparing a detergent composition for an automatic dishwasher as defined above. According to the method, components (a) to (h) of the composition and the water forming the remainder of the composition are combined and mixed into a uniform, homogeneous mixture.

The invention further relates to a method for washing soiled dishes in an automatic dishwasher in a water bath in which an effective amount of a liquid dishwasher detergent composition (NAPK) as defined above is dispersed. According to an aspect of the present invention, the NAPK composition can be easily poured into the cup of the dispenser of the dishwasher and thickens to its normal gel-like or paste-like state in just a few seconds to remain safely in the dispenser cup until shear forces such as washing were applied.

The invention will now be described in more detail by means of its specific embodiments and the following drawing, in which the figure is a graphical representation of the thixotropic index of two different combinations of formulas according to the present invention and the sa-Vella precipitated liquid dishwasher detergent composition disclosed in GB Patent 2,140,450A.

8

Previous GB publications 2,116,199A and 2,140,450A as well as U.S. Patent No. 4,752,409 show improved rheological properties as assessed by testing the viscosity of the product as a function of shear rate. The compositions had higher viscosity at low shear rate and lower viscosity at high shear rate, with data showing efficient liquefaction and gelation well in the range of shear rates of a standard dishwasher. In practice, this means improved flow and processing properties as well as less leakage from the machine's dosing cup compared to previous liquid and gel APP products. At shear rates of 3-30 rpm, the viscosities (Brookfield) ranged from about 10,000 to 30,000 cp to about 3,000 to 7,000 cp, respectively, measured at room temperature on an LVT-Brookfield-vis cosimeter after 3 minutes using No. 4. shuttle. The cutting speed of 7.4 s'1 corresponds to a rotational speed of about 3 rpm. An approximately ten-fold increase in shear rate causes an approximately 3-9-fold decrease in viscosity. The compositions of Applicant's prior invention thus have liquefaction thresholds at lower shear rates and a significantly higher volume when it comes to the ratio of the differential increase in shear rate to the differential decrease in viscosity. The property of the NAPK products of the present invention is the term thixotropic index (TI), which is the ratio of the apparent viscosity at 3 rpm and 30 rpm. Previous compositions have a TI of 2 to 10. NAPK compositions should have a significant and rapid return to previous dormant consistency when shear is interrupted.

When the determination of the thiotropic index TI as the ratio of the apparent viscosity at 3 and 30 rpm serves as a satisfactory measure of the usefulness of the product, further study and experience have shown that the reliability of by drawing the shear force S as a function of the shear rate as the shear rate increases from 0 to its maximum value and then returns to zero. The larger the area of the 91277 9 hysteresis loop, the larger the thixotropic index. The intrinsic viscosity has also shown that as long as the viscosity at room temperature (22 + 1 ° C) measured on a Brookfield viscometer HATD using shuttle number 4 at 20 rpm is less than about 20,000 cp, the composition can be easily shaken so that the thixotropic composition liquefies or "becomes flowable" to allow the product to be dispensed through a standard compressible tube, bottle or other cover dispenser.

The present invention is based on the astonishing finding that the same or better rheological properties and physical stability, e.g. duration of phase separation and settling, etc. can be achieved as in women previously in liquid aqueous APP compositions at significantly lower cost and without special process requirements a small but effective amount of long-chain fatty acid instead of a clay-like precipitant and, if used, also the metal salt of the fatty acid. At the same time, improvements in patching and film formation (e.g., less spots and less surface film) can be achieved.

As an example of improved rheological properties compared to standard clay-based thixotropic liquid APP, reference is made to the accompanying drawing, which is a plot of shear force S as a function of shear rate, η, for clay-based NAPP (3 wt% clay) (Kayra 1) and two similar. NAPP composition in which the clay is replaced by 0.06% stearic acid (Kayra 2) or 0.08% stearic acid (Kayra 3). The shear force, S, is measured in a static test using a Haake RV-3 equipped with a coaxial cup. The sample is placed in the outer cup and the machine rotates the inner cup incrementally at higher shear rates to a maximum of 113 s-^ and then at gradually decreasing shear rates to zero. The result is automatically plotted as shear force. The experiments were performed using the MV II sensor system (constant values, A = 3.76 Pa, M = 0.9 s 1). The area between the resulting curves 10 for each sample is a measure of thixotropy, with larger areas indicating higher thixotropy. The myth point of each sample can also be determined from the pattern assignment curve, the myotope point being the maximum force on the curve as a function of the shear force as a function of the shear rate. At the same time, the physical stability is such that even after six weeks or later, in the temperature ranges from almost freezing to 40 ° C and above, the compositions containing fatty acid precipitants do not pass through.

The long chain fatty acids used in the invention are higher aliphatic monocarboxylic acids having from about 8 to 22 carbon atoms, more preferably from about 10 to 20 carbon atoms, and most preferably from about 12 to 18 carbon atoms, including the carboxyl carbon atom of the fatty acid. An acid dimer or trimer may also be used. The aliphatic radical may be saturated or unsaturated and may be straight or branched. Of the straight chains, saturated fatty acid is preferred. Mixtures of fatty acids can be used, such as those obtained from natural sources such as tallow fatty acid, coconut fatty acid, etc., or from industrial manufacturing processes obtained from synthetic sources.

Thus, examples of fatty acids which can be used as precipitants instead of clay or polymeric precipitants include e.g. . In addition, myds can be used in dimers and trimers of these acids. Stearic acid and mixed fatty acids, e.g. coconut fatty acid, are preferred.

Within the carbon chain lengths of the monocarboxylic fatty acids specified herein, the viscosity of the product tends to decrease as the number of carbon atoms in the monocarboxylic fatty acid decreases. No regular orientations are observed for dimers or trimers of polybasic carboxylic acids.

11,91277

The amount of fatty acid thickener to achieve the desired thixotropic values and physical stability depends on factors such as the nature of the fatty acid, the detergent active component, inorganic salts, especially TPF, other NAPP ingredients, as well as the assumed storage and shipping conditions.

In general, however, levels of thixotropic fatty acid in the range of about 0.03-0.5%, preferably about 0.03-0.2%, more preferably about 0.03-0.08% provide long-term stability and keep phase separation out of the way. or during transport in both low and high temperatures as required for a commercially acceptable product.

In general, the potency of NAPPr is directly proportional to (a) the level of chlorine available, (b) the alkalinity, (c) the solubility in the detergent, and (d) the antifoam. Here, the pH of the NAPP composition should preferably be at least about 9.5, more preferably about 10.5-13.5, and preferably at least about 11.5. At relatively low pH values, the NAPP product is too viscous, e.g., solid-like, and thus not readily liquefiable at the shear force levels generated in the dispenser cup under normal machine operating conditions. In fact, the composition loses much if not all of its thixotropic nature. Thus, the addition of NaOH is often necessary to raise the pH within the aforementioned limits and to increase the flow properties. The presence of carbonate is often also necessary here, as it acts as a buffer, helping to maintain the desired pH level. However, excess carbonate should be avoided as it may cause the formation of needle-like carbonate crystals, thereby impairing the stability, thixotropy and / or detergent performance of the NAPP product, as well as impairing the dosability of the product from e.g. compressible tube bottles. Lipea (NaOH) in its presence still acts as a neutralizer of the phosphoric or phosphonic acid ester defoamer. About 0.5-3% by weight of NaOH and about 2-9% by weight of sodium carbonate in the NAPP composition are typical, although it should be noted that NaTPF and sodium silicate may produce the required alkalinity.

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NaTPF may be used in the NAPP composition in the range of about 8-35% by weight, preferably about 20-30% by weight, and should preferably be pure with respect to heavy metals that tend to degrade the tax to inactivate the preferred sodium hypochlorite and other chlorine bleach compounds. NaTPF may be anhydrous or as a hydrate, including a permanent hexahydrate having a degree of hydration of six, corresponding to about 18% by weight or more of water. In fact, given the stability of the hexahydrate, some water is very effective, it is thought to form stable hexahydrate seeds that accelerate the hydration and dissolution of the remaining NaTPF particles. If only hexahydrate is used, the detergent product may be too liquid and may have too little or no thixotropic character. Conversely, if only anhydrous NaTPF is used (the detergent product may in some cases be too thick and unsuitable for its pace. Particularly preferred NAPP compositions are obtained, e.g., using 0: 1-2: 1 by weight anhydrous to hexahydrate NaTPF. , with values of about 1: 1 being particularly preferred.

The importance of defoaming is important to increase the power of the dishwasher and to minimize the unstable effects that may occur if the machine contains excess foam during use. The foam can be sufficiently reduced by appropriately selecting the type and / or amount of detergent, the bulk component of the foam formation. The degree of foaming also depends somewhere on the hardness of the wash water in the machine, where the appropriate application of the ratios of NaTPF having a water softening power may help to produce the desired degree of antifoaming. However, it is generally preferred to include a chlorine bleach resistant antifoam or inhibitor. Alkylphosphonic acid esters of the formula 0 π are particularly effective

HO- P - R

OR

91277 13 available e.g. from BASF-Wyandotte (PCUK-PAE) and in particular alkyl acid phosphate esters of formula 0

II

HO - P -OR

OR

available e.g. from Hooker (SAP) and Knapsack (LPKn-158), where one or both R groups of each type of ester may independently represent ci2_2o_a ^ kyy ^ ry * 1, naa * Mixtures of the two types or any other chlorine bleaching may be used mixtures of a stable type or mono- and diesters of the same type. A mixture of mono- and di-C16-10-alkyl acid phosphate esters, such as a 1.2 / 1 mixture of monostearyl / distearyl acid phosphates (Knapsack), is particularly preferred. When used, ratios of 0.01 to 5% by weight, preferably 0.1 to 5% by weight, especially about 0.1 to 0.5% by weight of antifoam in the composition, are typical of the weight ratio of the detergent active component (d). the antifoam (e) is generally in the range of about 10: 1 to 1: 1 and preferably about 4: 1 to 1: 1. Other defoamers that can be used include, for example, known silicones.

Although any chlorine bleach compound may be used in the compositions of this invention, such as dichloroisocyanurate, dichlorodimethylhydantoin or chlorinated TSP, alkali metal, e.g. potassium, lithium, magnesium and especially sodium hypochlorite are preferred. The composition should contain sufficient chlorine bleach component to produce about 0.2-4.0% by weight of the available chlorine as determined, e.g., by acid treatment of 100 parts of the composition with excess hydrochloric acid. A solution containing about 0.2-4.0% by weight of sodium hypochlorite contains or produces roughly the same percentage of free chlorine. About 0.8-1.6% by weight of free chlorine is considered particularly good. For example, it is preferred to use a sodium hypochlorite solution containing from about 11% to about 13% free chlorine in an amount of about 3-20%, preferably 7-12%.

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Sodium silicate, which imparts alkalinity and protects hard surfaces such as fine porcelain glazing and patterning, is used as a dye in the composition of about 2.5-40% by weight, preferably about 10-35% by weight. At the higher levels specified herein, e.g., levels above about 10% by weight, the silicone also provides an increased anti-smudge effect. Sodium silicate is generally added as an aqueous solution, preferably with a Na 2 O: SiO 2 ratio of about 1: 2.2 to 1: 2.8, e.g. 1: 2.4. Most of the other components of the composition, especially NaOH, sodium hypochlorite and antifoam, can also be added in the form of an aqueous dispersion or solution.

Here, the usable detergent should be stable in the presence of a chlorine bleach, in particular a hypochlorite bleach, and water-dispersible surfactant types of organic anionic, amine oxide, phosphine oxides, sulfoxides or betaines are preferred, the former being anionic. They are used in the range of about 0.1-5%, preferably about 0.3-2.0%. Particularly preferred surfactants are linear or branched mono- and / or di- (C 1-4) -alkyl diphenyloxide mono- and / or disulfates of alkali metals, commercially available e.g. DOWFAX (registered trademark) 3B-2 and DOWFAX 2A -l.

In general, paraffin sulfonates tend to reduce, if not eliminate thixotropy, they have been found to unreasonably increase viscosity, causing severe shear problems. In addition, the surfactant should be compatible in composition with the other ingredients. Other suitable surfactants include primary alkyl sulfates, alkyl sulfonates, alkyl aryl sulfonates and sec-alkyl sulfates. Examples include sodium C 1 -C 4 alkyl sulfates such as sodium dodecyl sulfate and sodium fatty alcohol sulfate, sodium C 1 -C 4 alkane sulfonates such as sodium hexadecyl 1-sulfonate, and sodium C 2 -C 18 alkyl benzene benzene benzene benzene benzene benzene benzene. Corresponding potassium salts can also be used.

91277 15

As other suitable surfactants or detergents, amine oxide detergents are typically of the structure R 1, R 2 NO, wherein each R represents a lower alkyl group, e.g. methyl, and R represents a long chain alkyl group having 8 to 22 carbon atoms, e.g. lauryl, a myristyl, palmityl or cetyl group. Instead of the amine oxide, the corresponding surfactant phosphine oxide R2r1PO or sulfoxide RR1SO can be used. Betaine surfactants are typically of the form R 2 R 1 N - R "COO -, where each R represents a lower alkylene group having 1 to 5 carbon atoms. including dodecyldimethylammonium acetate, tetradecyldiethylammonium pentanoate, hexadecyldimethylammonium hexanoate, etc. For biodegradation, the alkyl groups of these surfactants should be linear, and such compounds are preferred.

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

Of course, the amount of water contained in these compositions should not be so high as to cause unreasonably low viscosity and fluidity, nor so low as to cause unreasonably high viscosity and low fluidity, with varying or destructive thixotropic properties in both cases. Such an amount is readily determined in any particular case by routine test arrangements, generally in the range of about 25-75% by weight, preferably 55-65% by weight. The water should also preferably be deionized or softened.

Other conventional ingredients may be included in these compositions in small amounts, generally less than about 3% by weight; such as perfume, hydrotropic agents such as sodium benzene, toluene, xylene and cumene sulfonates, preservatives, colorants and pigments and the like, 16 all of which, of course, are resistant to chlorine bleach and high alkalinity (properties of all components). Chlorinated phthalocyanines and polysulfides of aluminosilicate, which provide a pleasant green and blue color in this order, are particularly preferred for dyeing. TiO2 can be used for bleaching or neutralization of side tones.

The liquid APP compositions of the present invention are readily used in a known manner to wash dishes, other kitchen utensils and the like in a dishwasher equipped with a suitable detergent dispenser in a water bath containing an effective amount of the composition.

The invention may be practiced in many ways and a number of specific embodiments will be described to illustrate the invention with reference to the accompanying examples.

All amounts and ratios mentioned herein are by weight of the composition unless otherwise indicated.

Example 1

To illustrate the effect of the fatty acid precipitant, liquid APP formula combinations with various amounts of fatty acid-based thixotropic precipitant (Experiments 1, 2 and 3) are prepared according to Table 1. For comparison, a similar composition (Experiment No. 4) corresponding to the composition in Example 1 GB Patent 2,140,445A is prepared according to the procedure appended to said example.

91277 17

table 1

Component Test Test Test Test _ η: No. 1 No. 2 No. 3 No. 4

Water 32.99 32.96 32.94 41.92

Stearic acid 0.03 0.06 0.08

Clay (Gel White GP) - - 3.00

Sodium silicate (47.5% Na 2: 1: 2.4 solution in SiO 2) 25.00 25.00 25.00 13.73

Sodium tripolyphosphate (almost anhydrous, e.g.

approx. 3% moisture) 12.00 12.00 12.00 12.00

Sodium tripolyphosphate hexahydrate 12.00 12.00 12.00 12.00

Sodium carbonate (soda ash) 7.00 7.00 7.00 7.00

Sodium hypochlorite (13% free chlorine) 7.61 7.61 7.61 7.61

Surfactant (DOWFAX 3B-2, 45% aqueous solution of sodium mono- and didecyl di-phenyloxide disulfonate) 0.80 0.80 0.80 0.80

Antifoam (Knapsack LPK 158, a mixture of mono distearyl (C 15 -C 10) alkylphosphoric acid esters, molar ratio about 1: 1.3 0.16 0.16 0.16 0.16

Lip solution (50% NaOH) 2.40 2.40 2.40 2.40

Color (graphitol green) 0.01 0.01 0.01 0.01 100.00 100.00 100.00 100.00

A sample of the formula combinations of each of Experiments Nos. 2 and 3 and a vertical base clay of Formula (Experiment No. 4) are subjected to shear force measurement using a Haake RV-3 as described above to determine the thixotropic index and myotopic point. The results are shown in the accompanying figure, in which Kayra 1 is based on the sample of Experiment No. 4, Kayra 2 is based on the sample of Experiment No. 2, and Kayra 3 is based on the sample of Experiment No. 3. Myotope value - the maximum value of the shear force, S, is shown in Table 2.

18

Other properties are also shown in Table 2, including the intrinsic viscosity, 0, measured from a 24-hour-old sample using a Brookfield HATD viscometer, number 4 shuttle at 20 rpm (T = 22 ° + 1 ° C) (density, capillary). Capillary leakage rate (CDR) is a measure of stability at higher values indicating higher stability.CCDR measurements are made as follows: Whatman No. 1 filter paper with a circle drawn on a flat plate 6.4 cm in diameter is placed on a flat glass. , 10 cm x 10 cm Plastic tube, 6.4 cm long 3.4 cm in diameter is placed in a vertical position in the center of the circle.

The tubes are filled with sample liquid APP composition (after standing for one day). Measure the time it takes for the solution to seep out of the tube and reach the drawn circle.

Time is measured on three sides of a circle and averaged. Faster times mean that the gel does not hold enough solvent (water), which can then leak into the filter paper.

Times greater than about 7 minutes (all samples) are acceptable. The stability measurement is made by placing the sample in a glass bottle at room temperature and taking into account the% difference after four weeks. The centrifugation test is also a measure of stability. The glass centrifuge tubes are filled with equal volumes of each sample and rotated in an upright position, e.g., in a parallel plane in a Sorwall centrifuge for 25 minutes at 500 rpm. The volume of clear liquid is measured. The results are expressed as the ratio of the thickness of the clear liquid to the total thickness of the sample multiplied by 100, e.g.

the thickness of the clear liquid χ ^ qo. Lower figures indicate greater stability over the entire fluid thickness.

91277 19

Table 2

Feature Experiment 1 Experiment 2 Experiment 3 Experiment 4

Viscosity cP 11 460 10 660 11 260 5100

Myotopiste dyne / cm 2 - 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 at room temperature)% difference <1.0 0.0 0.0 5.0

Centrifugation <1.0 0.0 0.0 5.0

The data in Table 2 clearly show the superior phase separation stability of the stearic acid-based formula combinations.

These results, combined with the thixo, tropical properties shown in the graphical representations of the figure, further illustrate the superiority of the formula combinations of the invention with respect to the cup leakage of a dishwasher.

Example 2

Each of the formulas in Experiments 1 to 4 of Example 1 is tested to compare washing performance (formation of glassware spots and films) using a Kenmore dishwasher, using tap water at 54 ° C and a hardness of 120 ppm. The performance of the test is described in ASTM D 3566-79, except that only four washes are used. Film and spot formation are assessed on the following scales:

Membrane Rating Scale 1. Best, no clear film 2. Mild film formation, becoming apparent 3. Visible film, increasing 4. Significant and continuous film growth 5. Membrane formation becoming more extensive 6. Membrane formation high, large scale A. Best - no spots B. Very few clear spots C. Clear spots D. Clear about 50% coverage

The results are shown in Table 3:

Table 3

performance Evaluation

Experiment No. Tåplå Kalvo 1 B 1,2 2 B, C 1,2 3 B, C 2,3 4 C 2,3

Example 3

Results similar to those described above are obtained if stearic acid is replaced by isostearic acid, myristic acid, palmitic acid, lauric acid, Emphol dimer acid or Emphol trimer acid (long-chain carboxylic acids prepared by Emory Chemical, USA).

In addition to improved physical stability, thixotropy, and washing performance, the compositions of this invention further have the significant advantage that they do not require any particular order of addition of successive ingredients. All ingredients can be added in any order or simultaneously to one vessel, mixer, etc. and mixed until a uniform homogeneous mixture is obtained. Stirring can be performed at room temperature or at elevated temperature. It is not necessary to mix any of the ingredients in advance or to use different shear mixing conditions.

Claims (12)

91277 An aqueous thixotropic automatic dishwasher detergent composition, characterized in that it comprises approximately: (a) 5-35% alkali metal tripolyphosphate, (b) 2.5-40% sodium silicate, (c) 0-9% alkali metal carbonate, (d) 0.1-5% chlorine bleach-resistant, water-dispersible organic detergent, (e) 0-5% chlorine bleach-resistant defoamer, (f) chlorine bleach compound in an amount producing 0.2-4% available chlorine, (g) 0.03 -0.5% aliphatic fatty acid having Θ-22 carbon atoms, a dimer or trimer thereof, and (h) 0-8% sodium hydroxide, (i) the remainder of the composition being water. Composition according to Claim 1, characterized in that the aliphatic fatty acid (g) has 10 to 20 carbon atoms. Composition according to Claim 2, characterized in that the fatty acid has 12 to 18 carbon atoms. Composition according to Claim 1, characterized in that the fatty acid is stearic acid. Composition according to Claim 1, characterized in that the amount of fatty acid (g) is about 0.03 to 0.2%. Composition according to Claim 4, characterized in that the amount of fatty acid (g) is about 0.03 to 0.08%. Composition according to Claim 1, characterized in that the chlorine bleaching compound (f) is sodium hypochlorite. Composition according to Claim 1, characterized in that it contains at least 0.1% by weight of antifoam (.net). Composition according to Claim 8, characterized in that the antifoam agent is an alkyl acid phosphate ester or an alkylphosphonic acid ester containing one or two C 1-20 alkyl groups, or a mixture thereof. The composition of claim 1, characterized in that it has a pH of about 10.5 to 13.5. A process for preparing an aqueous thixotropic detergent composition for an automatic dishwasher, characterized in that the components of the detergent composition having by weight proportions of approximately: (a) 5-35% alkali metal tripolyphosphate, (b) 2.5-40% sodium silicate , (c) 0-9% alkali metal carbonate, (d) 0.1-5% chlorine bleach-resistant, water-dispersible organic detergent, (e) 0-5% chlorine bleach-resistant defoamer, (f) chlorine bleach compound in an amount of 0.2 -4% available chlorine, (g) 0.03-0.5% aliphatic fatty acid having 8-22 carbon atoms, a dimer or trimer thereof, and (h) 0-8% sodium hydroxide, and the remainder of the composition is combined with water. and mixed to a uniform, homogeneous mixture. A method for washing soiled dishes in an automatic dishwasher, characterized in that the dishes are placed in a dishwasher in a water bath dispersed with an effective amount of a detergent composition containing by weight about: (a) 5-35% alkali metal polyol; 5-40% sodium silicate, (c) 0-9% alkali metal carbonate, 91277 (d) 0.1-5% chlorine bleach-resistant, water-dispersible organic detergent, (e) 0-5% chlorine bleach-resistant defoamer, (f) chlorine bleach compound yielding 0.2-4% available chlorine, (g) 0.03-0.5% aliphatic fatty acid having 8-22 carbon atoms, a dimer or trimer thereof, and (h) 0-8% sodium hydroxide, (i) the remainder of the composition being water.