FI93553B - Thixotropic liquid detergent mixture for dishwasher - Google Patents

Description

93553

This invention relates to an aqueous, thixotropic liquid dishwasher detergent composition having improved physical stability. More specifically, the invention relates to the use of potassium polyphosphates and metal salts of long chain fatty acids as physical stabilizers for aqueous suspensions of thixotropic clay used as dishwashing detergents.

The addition of small effective amounts of potassium polyphosphate and small effective amounts of polyvalent metal salts of long chain fatty acids significantly improves the variability of physical stability and theological properties over time with detergent compositions containing aqueous suspensions of thixotropic clay. Thixotropic properties can be maintained or improved by using smaller amounts, such as 0.25-0.50% thixotropic clay thickener, than without potassium polyphosphate stabilizers.

In particular, this invention relates to detergent compositions for automatic dishwashers which have thixotropic properties, improved chemical and physical stability against variations in theological properties over time, and which have increased apparent viscosity and are easy to use; mail dispersible in a washing medium for efficient cleaning of food containers, glassware, porcelain and the like.

Commercially available household dishwasher detergents supplied in powder form have several disadvantages, e.g., non-uniform composition, expensive steps required to manufacture them; the tendency to agglomerate when stored in high humidity, leading to the formation of lumps that are difficult to disperse; dustiness, a special source of irritation for users suffering from allergies; tendency to clump in the dishwasher dispenser.

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Recent research and development has focused on the gel or "thixotropic" form of such compositions, e.g., abrasive detergents and detergent products for automatic dishwashers, which are characteristically thixotropic pastes. The dishwashing products thus obtained are suspect mainly because they are insufficiently viscous to remain "anchored" in the dispensing cup of the dishwasher. Ideally, thixotropic cleaning compositions would be highly viscous in a stationary state, Bingham plastic in nature, and have relatively high yield point values. However, when subjected to shear stresses, such as when shaken in a container or extruded through a nozzle, they should rapidly liquefy and, upon interruption of the shear stress applied to them, they quickly return to a highly viscous / Bingham plastic state. Stability is also paramount, i.e. no significant phase separation or leakage should occur after long standing.

NO patent publication 166 091 discloses dishwashing detergent compositions of aqueous thixotropic clay suspensions containing aluminum stearate as a physical stabilizer. The compositions of the publication show an improvement in the physical stability of the detergent composition and an improvement against phase separation compared to clay-containing compositions which do not contain aluminum stearate. However, the compositions of the present invention have in some cases found difficulty in achieving stability against variations in rheological properties over time and with large temperature changes, and have generally required a relatively high clay content, such as 0.25-2.0%.

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The provision of gel detergent detergent compositions for automatic dishwashers having the above-mentioned properties, with the exception of the improvements described in the above-mentioned NO patent publication 166 091, has thus proved to be problematic for a long time, especially for 3,93553 compositions for household dishwashers. For efficient use, it is generally recommended that an automatic dishwasher detergent, hereinafter also referred to as ADD, contain (1) sodium tripolyphosphate (NaTPP) to soften hard water or to bind minerals therein and to emulsify and / or peptize dirt; (2) sodium silicate to provide the alkalinity necessary for an effective washing effect and to provide porcelain clear glaze and pattern protection; (3) sodium carbonate, which is generally considered optional, to increase alkalinity; (4) a chlorine-releasing agent to help remove dirt stains that lead to the formation of water spots; and (5) a defoamer / surfactant to reduce foam, which improves machine efficiency and provides the required washing power. See. for example, SDA Detergents in Depth, "Formulations Aspects of Machine Dishwashing," Thomas Oberle (1974). Detergents corresponding approximately to the mixtures described above are mostly liquids or powders. Combining these ingredients into a gel form that is effective for household appliance use has proven difficult. In general, such mixtures lack a hypochlorite bleach because it tends to react with other chemically active ingredients, especially surfactants. Accordingly, U.S. Patent 4,115,308 discloses thixotropic pastes for automatic dishwashers containing suspending agents, e.g., CMC, synthetic clays, and the like; inorganic salts such as silicates, phosphates and polyphosphates, a small amount of a surfactant and a defoamer. Bleach is not described. U.S. Patent 4,147,650 is somewhat similar, optionally containing a Cl (hypochlorite) bleach, but not an organic surfactant or defoamer. In addition, the product is described as a detergent slurry without thixotropic properties.

U.S. Patent 3,985,668 discloses abrasive cleaners having a gel-like consistency and containing (1) a suspending agent of 4,93553 suspensions, preferably clay or attapulgite type clay; (2) an abrasive, e.g., silica sand or perlite; and (3) a filler consisting of low density powdered polymers, expanded perlite, etc., which has a buoyancy and thus a stabilizing effect on the mixture in addition to acting as a flocculant, avoiding water that would otherwise be available due to undesirable overlay formation and phase destabilization. The above are essential ingredients. Optional ingredients include hypochlorite bleach, a bleach stable surfactant, and a buffering agent, e.g., silicates, carbonates, and monophosphates. Excipients such as NaTPP may be included in the mixture as optional additives to provide or supplement an adjuvant that is not provided by the buffering agent, up to a maximum of 5% of the total mixture. according to the patent. Maintaining the desired pH levels above 10 is achieved with buffer / excipient components. A high pH is said to reduce the degradation of chlorine bleach and the undesirable interaction between the surfactant and the bleach. When NaTPP is present, it is limited to 5%, as mentioned. Defoamer is not described.

GB Patent Applications 2116199 A and 2140450 A, both of which have been granted to Colgate-Palmolive, disclose liquid ADD mixtures having properties which are desirably characteristic of a thixotropic, gel-like structure and which contain all of them in various forms. ingredients needed to achieve an effective washing effect with an automatic dishwasher. Normally a gel-like aqueous detergent mixture for an automatic dishwasher with a thixol. tropical properties, contains the following ingredients by weight.

(a) 5-35% alkali metal tripolyphosphate; (b) 2.5-20% sodium silicate; (c) 0-9% early metal carbonate;

II

5,93553 (d) 0.1-5% chlorine bleach stable, water dispersible, active organic detergent material; (e) 0-5% chlorine bleach stable defoamer; (f) a chlorine bleaching compound in an amount to provide about 0.2-4% available chlorine; (g) a thixotropic thickener in an amount sufficient to give the mixture a thixotropic index of about 2.5 to 10; (h) sodium hydroxide as needed to adjust the pH; and (i) the remaining water.

The ADD blends thus blended are low foaming; are readily soluble in the detergent detergent and are most effective at pH values which best affect the improved cleaning performance, namely at pH values of 10.5-14.0. The mixtures normally have a gel consistency, i.e. they are very viscous, opaque petrolatum-like materials with a Bingham plastic character and thus relatively high yield strengths. Under such conditions, the mixture is rapidly liquefiable and easily dispersible. When the shear force is removed, the liquid mixture quickly returns to a high viscosity, Bingham plastic state that closely resembles its previous consistency.

U.S. Patent 4,511,487, issued April 16, 1985, describes a low-foaming detergent paste for dishwashers. The patented thixotropic cleaning agent has a viscosity of at least 30 Pa.s at 20 ° C as measured by a rotary viscometer at a spindle speed of 5 rpm. The mixture is based on a mixture of finely divided hydrated sodium metasilicate, an active chlorine compound and a thickener which is a hectorite. type of leaf silicate. Small amounts of nonionic surfactants and alkali metal carbonates and / or hydroxides may be used.

The formation of organic clays by the reaction 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)].

Although these previously described liquid ADD formulations are not susceptible or to a lesser extent susceptible to one or more of the deficiencies described above, it has been found that further improvements in physical stability and stability against variations in theological properties over time are desired to prolong product shelf life and thus improve consumer shelf life.

At the same time, it would be highly desirable to improve other clay-based thixotropic liquid formulations, such as abrasive cleaners; the physical stability and stability of toothpastes, "liquid" soaps, etc. against variations in theological properties over time.

Accordingly, it is an object of the present invention to provide a solution for preventing settling in thixotropic aqueous clay suspensions used as a dishwasher detergent.

Another object of the present invention is to provide liquid ADD compositions having thixotropic properties and improved physical stability and improved stability against variations in theological properties over time.

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Yet another object of this invention is to provide thixotropic liquid ADD blends with reduced amounts of thixotropic thickener without adversely affecting the generally high viscosities at low shear rates and the lower viscosities at high shear rates characteristic of the desired thixotropic properties.

It is still another object of this invention to improve aqueous thixotropic, clay-based compositions, especially liquid, automatic dishwasher detergent pastes; 7 93553 or gels by adding a smaller amount of potassium polyphosphates and a smaller amount of a fatty acid metal salt to the aqueous clay suspension, which is effective in preventing the settling of suspended particles and preventing phase separation.

It is a further object of this invention to improve the stability of aqueous, thixotropic, clay-based compositions, especially liquid automatic dishwasher detergent pastes or gels, against variations in rheological properties over time by adding a small effective amount of potassium polyphosphate and a small effective amount of fatty acid to the clay aqueous suspension.

The aqueous, thixotropic liquid dishwasher detergent composition according to the invention is characterized in that it contains 0.1 to 0.5% by weight of clay as thixotropic agent, 0.5 to 3.0% by weight of potassium polyphosphate, 0.1 to 0.5% by weight of % of a metal salt of at least one long chain fatty acid, wherein the potassium polyphosphate and the metal salt of the fatty acid improve the physical stability and stability of the mixture against variations in rheological properties over time, water and at least one additive selected from the group consisting of organic detergents, pH modifiers, chlorine bleaching aids, sequestrants, defoamers, abrasive particles and mixtures thereof.

A particular embodiment of the invention is a normally gel-like aqueous automatic dishwasher detergent composition having thixotropic properties and containing by weight: (a) 5-35% sodium tripolyphosphate; (b) 2.5-20% sodium silicate; (c) 0-9% time methyl carbonate; (d) 0.1-5% chlorine bleach stable, water dispersible, active organic detergent material; 8,93553 (e) 0-5% chlorine bleach stable foam reducer; (f) the chlorine bleach compound in an amount to provide about 0.2-4% available chlorine; (g) 0.1-0.5% clay as a thixotropic thickener to impart a thixotropic index of about 2.5-10 to the mixture; (h) 0-8% sodium hydroxide; (i) 0.5-3.0% of at least one potassium tripolyphosphate, potassium pyrophosphate and potassium hexametaphosphate; (j) 0.1 to 0.5% of a polyvalent metal salt of a long chain fatty acid; and (k) the remaining water.

Likewise, in connection with this particular aspect, the present invention relates to a method of cleaning food containers in an automatic washing machine with an aqueous washing bath containing an effective amount of the liquid automatic dishwasher detergent (LADD) described above. According to this aspect of the invention, the LADD mixture can be easily poured into the dispensing cup of an automatic dishwasher and thickens rapidly, in just a few seconds, to a normal gel-like or pasty state.

In general, the efficiency of a LADD mixture is directly proportional to (a) the available chlorine levels; (b) early; (c) solubility in the detergent; and (d) foam prevention. In this context, it is preferred that the pH of the LADD mixture be at least about 9.5, more preferably about 10.5-14.0, and most preferably at least n.

11.5. In this context, the presence of carbonate is often also required, as it acts as a buffering agent, helping to maintain the desired pH level. However, excess carbonate must be avoided as it can cause the needle-like crystals of carbonate to form. which impairs the stability, thixotropic and / or washing performance of the LADD product and impairs the distribution of the product from, for example, compression tube bottles. An additional function of sodium hydroxide (NaOH) is to neutralize the phosphoric or phosphoric acid ester used as an antifoam when present. About 0.5-6% by weight of NaOH and about 2-9% by weight of sodium carbonate in the LAED-9 93553 mixture are typical, although it should be noted that sufficient alkalinity can be achieved with NaTPPrn and sodium silicate.

The amount of NaTPPrn used in the LADD mixture in an amount of about 8-35% by weight, preferably about 20-30%, should preferably be free of heavy metals that tend to degrade or inactivate the preferred sodium hypochlorite and other chlorine bleaching compounds. NaTPP may be anhydrous or hydrated, including a stable hexahydrate having a degree of hydration 6 corresponding to about 18% by weight or more of water. Particularly preferred LADD mixtures are obtained, for example, by the use of anhydrous and hexahydrated NaTPPra in weight ratios of 0.5rl to 2rl, with values of about lrl being particularly preferred.

Foam control is important to improve the efficiency of the dishwasher and to minimize the destabilizing effects that may occur due to the presence of excess foam in the machine during use. Foam can be sufficiently reduced by appropriate selection of the type and / or amount of active detergent material, which is the main foam-producing component. The degree of foaming also depends to some extent on the hardness of the water in the machine, so that appropriate adjustment of the amounts of NaTPPr, which has a water softening effect, can help to achieve the desired Hillin grade of the foam. In general, however, it is preferable to include in the mixture a chlorine bleach stable foam reducing or curing agent. Particularly effective are alkylphosphonic acid esters of formula 0

HO - P - R

OR

available from BASF-Wyandotte (PCUK-PAE), and in particular phosphate esters of alkyl acid of formula 0

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HO - P - OR

OR

10,93553 available, for example, from Hooker (SAP) and Knapsack (LPKn-158), in which one or both of the R groups in each ester type may independently represent C 2 · Mixtures of the two types or any other chlorine bleach stable types or the same mixtures of mono- and diesters of this type can be used. Particularly preferred is a 1.2 / 1 mixture of mono- and di-C 1-6 alkyl acid phosphate esters, such as monostearyl and di-stearyl acid phosphates (Knapsack) or (Ugine Kuhlman). When defoamers are used, amounts of 0.1 to 5% by weight and preferably about 0.1 to 0.5% by weight in the mixture are typical, with the weight ratio between the active detergent component (d) and the defoamer (e) varying. generally between about 10: 1-1: 1 and preferably about 5: 1-1: 1. Other defoamers that can be used include, for example, known silicones. In addition, a preferred feature of the present invention is that many of the stabilizing salts, such as stearate salts, for example aluminum stearate, are also effective defoamers.

Although any chlorine bleaching compound can 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 mixture should contain sufficient chlorine bleach compound to provide about 0.2-4.0% by weight of available chlorine as determined, for example, by acidifying 100 parts of the mixture with excess hydrochloric acid. A solution containing about 0.2-4.0% by weight of sodium hypochlorite contains or provides the same percentage of available chlorine. About 0.8-1.6% by weight of available chlorine is a particularly preferred amount. For example, a solution of sodium hypochlorite (NaOCl) with about 11-13% available chlorine can be used in amounts of about 3-20%, and more preferably about 7-12%.

Sodium silicate, which provides alkalinity and protection for hard surfaces such as porcelain glaze and images, is used in the mixture in an amount ranging from about 2.5 to 20% by weight, preferably from about 5 to 15% by weight. Sodium silicate is generally added in the form of an aqueous solution in which the ratio of Na 2 O: SiO 2 is preferably about 1: 2 to 1: 2.8.

The active detergent material used in this connection must be stable in the presence of a chlorine bleach, in particular a hypochlorite bleach, and water-dispersible surfactants of the organic anionic, amine oxide, phosphine oxide, sulfoxide or betaine type are preferred, with the former being the most preferred. They are used in amounts ranging from n.

0.1-5% and preferably between about 0.3-2.0%. Particularly preferred surfactants in this context are linear or branched mono- and / or disulfates or disulfonates of alkali metal mono- and / or di- (C 1-4) -alkyl diphenyl oxide, which are commercially available, for example under the name Dowfax (registered trademark) 3B-2 and Dowfax 2A-1. In addition, the surfactant must be compatible with the other ingredients of the mixture. Other suitable surfactants include primary alkyl sulfates, alkyl sulfonates, alkyl aryl sulfonates, and sec-alkyl sulfates. Examples are sodium C 10 C 18 alkyl sulphates such as sodium dodecyl sulphate and sodium tallow alcohol sulphate, sodium C 1 -C 4 alkane sulphonates such as sodium hexadecyl 1-sulphonate and sodium C 1 -C 4 alkyl benzene sulphonate decene sulphonates such as sodium. Corresponding potassium salts can also be used.

As other suitable surfactants or detergents, amine surfactants typically have the formula I, wherein each R represents a lower alkyl group, for example a methyl group, and R 1 represents a long chain alkyl group having 8 to 22 carbon atoms, e.g. lauryl, myristyl, palmityl or cetyl. Instead of the amine oxide, the corresponding surfactant phosphine oxide R2R2PO or sulfoxide RR1SO can be used. Betaine surfactants typically have the structure R2R1NR'COO-, where each R represents a lower alkylene group having 1 to 5 carbon atoms. Typical examples of these 123553 surfactants are lauryl dimethylamine oxide, myristyl dimethylamine oxide, the corresponding phosphine oxides, and sulfoxides and the corresponding betaines, including dodecyldimethylammonium acetate, tetradecyldentanylamide, tetradecyldiethylammonium petradecyldiethylammonium. be linear and such compounds are preferred.

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

Thixotropic thickeners, i.e. thickeners or suspending agents which impart thixotropic properties to an aqueous medium, are known in the art and may be organic or inorganic aqueous solutions, water-dispersible or colloidal, and monomeric or polymeric, and must, of course, be stable in these mixtures. stable to highly alkaline and chlorine bleaching compounds such as sodium hypochlorite. Particularly preferred thickeners generally consist of inorganic, colloid-forming clays of the smectite and / or attapulgite type. These materials were generally used in amounts of about 1.5-10 and preferably 2-5% by weight to provide the desired thixotropic properties and Bingham plastic nature in the LADD configurations previously filed by the assignee of the aforementioned GB patent applications 2116199 A and 2140450 A. . One advantage of the LADD formulations of this invention is that the desired thixotropic properties and Bingham plastic nature can be achieved in the presence of potassium polyphosphates and the metal hydrochloric acid stabilizers of this invention using smaller amounts of thixotropic thickeners. For example, amounts of inorganic colloid-forming clays of the smectite and / or attapulgite types in the range of about 0.1-0.5%, preferably 0.2-0.4% and especially 0.25-0.30% are generally sufficient for the desired thixotropic properties and Bingham plastic nature when used in combination with 95553 13 potassium polyphosphates and metal salt stabilizers for physical fatty acids.

Smectite clays include montmorillonite (bentonite), hectorite, attapulgite, smectite, saponite, etc. Montmorillonite clays are preferred and are available under trade names such as Thixogel (registered trademark) No. 1 and Gelwhite (registered trademark) GP, H, etc. manufactured by Georgia Kaolin Company; and Eccagum (registered trademark) GP, H, etc. manufactured by Luthern Clay Products. Attapulgite includes materials commercially available under the tradename Attagel (registered trademark), i.e., Attagel 40, Attagel 50, and Attagel 150, manufactured by Engelhart Minerals and Chemicals Corporation. Mixtures of smectite and attapulgite types in weight ratios of 4: 1 to 1: 5 are also useful in this context. Thickening or suspending agents of the above type are well known in the art and are described, for example, in U.S. Patent 3,985,668, which is incorporated herein by reference. Rubbing! polishes should be avoided in LADD mixtures as they can scratch the surface of food containers, crystals, etc.

The amount of water contained in these mixtures must not, of course, be so high as to cause an unreasonably low viscosity and sensitive fluidity, nor so small that it; produces unreasonably high viscosity and poor flowability, with deterioration or destruction of thixotropic properties in either case. This amount is easily determined by routine experimentation in each case, generally ranging from about 30 to 75% w / w, preferably from about 30 to 65% by weight. The water should preferably also be deionized or plasticized.

For the time being, the description of the LADD product is, unless otherwise stated, consistent with the blends described in the aforementioned GB patent applications 2116199 A and 2140450, the rights of which have been granted to the rights holder of this application.

The LADD products of 14,93553 GB patent applications 2116199 A and 2140450 have improved theological properties when evaluated by testing the viscosity of the product as a function of shear rate. The blends had higher viscosities at low shear rates and lower viscosities at high shear rates, with the results showing efficient liquefaction and gelation at the shear rates found in a standard dishwasher. In practice, this means improved pour and process properties as well as less leakage from the machine's distribution cup compared to previous liquid or gel ADD products. At the shear rates used, which correspond to rotational speeds of 3-30 rpm, the viscosities (Brookfield) ranged from about 10,000 to 30,000 mPa.s to 2,000 to 6,000 mPa.s measured at room temperature with an LVT Brookfield viscometer after 3 minutes using a spindle no. 4 one day after manufacture. The cutting speed of 7.4 s'1 corresponds to a spindle speed of approx. 3 rpm. An approximately ten-fold increase in shear rate causes a decrease in viscosity of about 3-9 times. With previous ADD gels, the corresponding decrease in viscosity was only about twofold. Moreover, the initial viscosity obtained with such mixtures at a rotational speed of about 3 rpm was only about 2500-2700 mPa.s. Thus, the compositions of the prior art owner of this invention have a liquefaction threshold at lower shear rates and to a significantly greater extent as measured by differential increases in shear rate as a function of the differential decrease in viscosity. This property of the LADD products of the previous invention has been summed up as the thixotropic index (TI), which is the ratio of the apparent viscosities at 3 and 30 rpm. The TI values of the previous mixtures are between 2-10. The LADD blends tested showed a substantial and rapid recovery to previous stationary state consistency when shear force was removed.

The present invention is based on the finding that the physical stability, i.e. resistance to phase separation, settling, etc., of liquid aqueous ADD mixtures of GB Patent Applications 2116199 A and 2140450 and NO 166 091 can be significantly improved or adversely affected at the same time. stability against variations in theological properties as time and temperature change by adding a small but effective amount of potassium polyphosphates and small but theocal amounts of a long chain fatty acid metal salt to the mixture.

As an example of the improvement in theological properties, it has been found that viscosities at low shear rates, e.g. about 3 spindle speeds, can often be increased 2-3 times by adding only 1-2% or less potassium polyphosphates and only 0.25-0.50% as a stabilizer. a functional metal salt of a fatty acid. At the same time, physical stability can be improved to the extent that even after 12 weeks or more in temperature ranges close to freezing to 40 ° C and above, mixtures containing potassium polyphosphate and metal salt stabilizers are stable against variations in theological properties over time and temperature. and there is no visible phase separation.

Potassium polyphosphates that can be used are generally commercially available. Typical examples of potassium polyphosphates are potassium tripolyphosphate (TPP), potassium pyrophosphate and potassium hexametaphosphate. Potassium tripolyphosphate (TPP) is preferred.

The amount of potassium polyphosphates required to achieve the desired improvement in physical stability depends on factors such as the nature of the fatty acid salt, the active ingredient of the thixotropic detergent compound, inorganic salts, sodium TPP and other LADD components, and the nature and amount of the ingredient.

The amounts of potassium polyphosphates used as stabilizers (50% of active ingredient) which can be used are between about 0.5-3.0%, preferably about 0.80-2.0% and particularly preferably about 1.0-1, 8%.

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Preferred long chain fatty acids are higher aliphatic fatty acids having about 8 to 22 carbon atoms, more preferably about 10 to 20 carbon atoms, and particularly preferably about 12 to 18 carbon atoms, including the carbon atom of the carboxyl group of the fatty acid. 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 can be used, such as those derived from natural sources such as tallow fatty acid, coconut fatty acid, soybean fatty acid, etc., or synthetic sources available from industrial digestion processes.

Thus, examples of fatty acids from which polyvalent metal stabilizers can be formed include, for example, capric acid, lauric acid, palmitic acid, myristic acid, stearic acid, oleic acid, eicosanic acid, tallow fatty acid, coconut fatty acid, soybean fatty acid, soybean fatty acid, soybean fatty acid, soybean fatty acid. low cost.

Preferred metals are the polyvalent metals of groups IIA, IIB and IIIB, such as magnesium, calcium, aluminum and zinc, although other polyvalent metals, such as those of groups IIIA, IVA, VA, VIA, VIIA, IB, IVB, VB, VIB, VIIB of the Periodic Table of the Elements and VIII metals can also be used. Typical examples of such other polyvalent metals are .. Ti, Zr, V, Nb, Mn, Fe, Co, Ni, Cd, Sn, Sb, Bi, etc. In general, the metals may be present in a divalent to pentavalent state. It is preferred to use metal salts in their higher oxidation states. Of course, for LADD mixtures as well as other mixtures in which the mixture of this invention is or may come into contact with articles used in the handling, storage or serving of food products or which may otherwise come into contact with or consumed by humans or animals, the metal salt should be selected taking into account metal toxicity. For this purpose, calcium and magnesium salts are very particularly preferred as generally safe food additives.

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Many of these metal salts are commercially available. For example, aluminum salts are available in tribasic form, e.g. aluminum stearate as aluminum tristearate, Al (^ H ^ COO) 2 ♦ Monobasic salts, e.g. aluminum monostearate, AKOH ^ iC ^ H ^ COO) and dibasic salts, e.g. aluminum distearate, Al (^ H ^ COO) OH) (C 1 H 2 COO) 2 and mixtures of two or three mono-, dibasic and tribasic salts can be used with these metals, e.g. ali with valences of +3, and mixtures of mono- and dibasic salts can be used with these metals , e.g., with Zn having valencies of +2. It is most preferred that the dibasic salts of +2-valence metals and the tribasic salts of +3-valence metals, the quaternary salts of +4-valence metals and the pentavalent salts of +5-valence metals are used in predominant amounts. For example, at least 30%, preferably at least 50%, especially 80-100% of the total metal salt should be in the highest possible oxidation state, i.e. each of the possible valence sites is occupied by a fatty acid residue.

The above-mentioned metal salts are generally commercially available, but can be easily prepared, for example, by saponification of a fatty acid, e.g. animal fat, stearic acid, etc. or a corresponding fatty acid ester, followed by treatment with a polyvalent metal hydroxide or oxide, e.g. alum, alumina, etc.

Calcium stearate, i.e. calcium distearate, magnesium stearate, i.e. magnesium distearate, aluminum stearate, i.e. aluminum tristearate and zinc stearate, i.e. zinc distearate, are preferred polyvalent fatty acid salt stabilizers. It is also preferred to use metal salts of mixed fatty acids, such as naturally occurring acids, e.g. coconut acid, as well as commercially available mixed fatty acids from the manufacturing process as a cheap but effective source of long chain fatty acids.

The amount of potassium polyphosphate and fatty acid salt stabilizers to achieve the desired improvement in physical stability,. 93553 also depends on such factors as the nature of the fatty acid salt, the nature and amount of the thixotropic agent, the active ingredient of the detergent, the inorganic salts, NaTPPr, other LADD ingredients, as well as the expected storage and transport conditions.

In general, however, the amounts of polyvalent metal salts of fatty acids as stabilizers are between about 0.10 and 0.5%, preferably between about 0.2 and 0.4% and particularly preferably between about 0.25 and 0.30%. The use of potassium polyphosphates in combination with polyvalent metal salts of fatty acids as stabilizers provides long-term physical stability, stability against variation in theological properties with time and temperature, and absence of phase separation when standing or transporting the mixture at both low and high temperatures as commercially acceptable.

In another embodiment of the invention, the fatty acids themselves can be used as stabilizers instead of the metal salts of the fatty acid described above.

The long chain fatty acids that can be used are, for example, higher aliphatic fatty acids having about 8 to 22 carbon atoms, preferably about 10 to 20 carbon atoms, and even more preferably about 12 to 18 carbon atoms, including the carbon atom of the carboxyl group of the fatty acid. The aliphatic radical may be saturated or unsaturated and may be straight or branched chain. Straight chain saturated fatty acids are preferred. Mixtures of fatty acids can be used, such as those derived from natural sources such as tallow fatty acid, coconut fatty acid, soybean fatty acid, etc., or synthetic sources available from industrial manufacturing processes.

Thus, examples of fatty acids that can be used as stabilizers include, for example, capric acid, lauric acid, palmitic acid, myristic acid, stearic acid, behenic acid,; oleic acid, eicosanic acid, tallow fatty acid, coconut fatty acid, 19 93553 soybean fatty acid, mixtures of these acids, etc. Benoic acid, stearic acid and mixed fatty acids can be used.

Many of the fatty acids are commercially available. For example, stearic acid and behenic acid are readily available. Mixed fatty acid and, like naturally occurring acids, e.g. coconut acid, as well as mixed fatty acid obtained from a commercial manufacturing process, and it is also preferred to use as a cheap but effective source of long chain fatty acids. Sodium and potassium salts of fatty acids can also be used as stabilizers.

The amount of fatty acid stabilizers and / or their sodium or potassium salts that can be used is in the same range as the amount of the above-mentioned fatty acid metal salts.

From the following examples, it can be seen that depending on the amount, proportions and types of physical stabilizers and thixotropic agents, the addition of potassium polyphosphates and fatty acid salt not only improves physical stability but also in some cases with temperature.

Physical stabilizers are added just before the addition of the clay thickener. Excluding the chlorine bleach compound, the total content (NaTPP, sodium silicate and carbonate) is generally n.

20-50% by weight, preferably about 30-40% by weight in the mixture.

In a preferred method of mixing the ingredients of the LADD formulations, a mixture of water, a defoamer, a detergent, physical stabilizers (potassium tripolyphosphate and fatty acid salt) and a thixotropic agent, e.g. clay, is first formed. These ingredients are mixed together under high shear conditions, preferably starting at room temperature to form a uniform dispersion. To this premixed portion, the remaining ingredients are added under low shear mixing conditions. For example, the required amount of premix is fed to a low shear mixer and then the remaining ingredients are added with mixing either sequentially or simultaneously. The ingredients are preferably added sequentially, although it is not necessary to complete all additions of one ingredient before adding the next ingredient. In addition, one or more ingredients may be subdivided and added at different times. Good results have been obtained by adding the remaining ingredients in the following order: sodium hydroxide, alkali metal carbonate, sodium silicate, sodium tripolyphosphate (hydrated), sodium tripolyphosphate (anhydrous or containing up to 5% water), bleach (preferably sodium hypochlorite) and sodium.

Other conventional ingredients may be included in these mixtures 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, etc., all of which are naturally stable to chlorine. bleaching compound and high alkalinity (properties of all components). Particularly preferred for dyeing are chlorinated phthalocyanines and polysulfides of aluminosilicate, which provide pleasant shades of green and blue, respectively. TiCl 2 can be used for folded shades; lightening or neutralizing them.

The liquid ADD compositions of the present invention are easy to use in a known manner for washing dishes, other kitchen utensils, etc. in an automatic dishwasher equipped with a suitable detergent dispenser in an aqueous washing bath containing an effective amount of the mixture.

Although the present invention has been described specifically for its application to liquid automatic dishwasher detergents, it will be readily apparent to one skilled in the art that the benefits of adding potassium tripolyphosphate and a long chain fatty acid metal salt, namely improved physical stability and stability over clay-based thixotropic 93553 21 suspension are equally suitable for other clay-based thixotropic suspensions used as dishwashing detergents.

The present invention may be practiced in various ways, and numerous 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 mixture unless otherwise indicated.

Example 1

To demonstrate the effect of potassium tripolyphosphate and metal salt stabilizers, liquid ADD formulations are prepared with varying amounts of potassium tripolyphosphate and fatty acid salt stabilizers and a thixotropic clay thickener as follows:

Thixotropic clay formations

percent

Ion-exchanged water (adjusted to 100%) 33.06-42.55

Monostearyl phosphate 0.16

Dowfax 3B2 (45% monodecyl / didecyl diphenyloxide sulfonate - aqueous solution) 0.8

Potassium TPP (50% active ingredient) 0-1.6

Aluminum stearate 0 to 0.4

Pharmagel H 0.25-2.0 These products are mixed together at high shear at room temperature and the following ingredients are then added at room temperature.

Sodium hydroxide solution (50% NaOH) 2.2 - 10.2

Sodium carbonate, anhydrous 5.00

Sodium silicate, 47.5% solution,

Na 2 O: SiO 2 ratio 1: 2.4 15.74 22 93553

Sodium TPP hexahydrate (Thermphos N hexa) 12.00

Sodium TPP (essentially anhydrous, i.e.

0.5% and especially 3% moisture) (Thermophos NW) 12.00

Sodium hypochlorite solution (11% available chlorine) 9.00

Liquid ADD formulations 1-9 are prepared and measured for density, apparent viscosity at 3 and 30 ppm, and physical stability (phase separation) during standing and transport test. The results obtained are shown in the following Tables I and II.

The results reported in Tables I and II lead to the following conclusions: Addition of 0.1% aluminum stearate to the formulation containing 1.25% Pharmagel H, Run 2 (revision) results in an increase in physical stability without altering the apparent viscosity compared to Run 1 (revision).

Adding 0.4% aluminum stearate to the formulation containing 0.25% Pharmagel H, Run 3 (revision) results in increases in physical stability and apparent viscosity compared to runs 1 (revision) and 3 (revision). The use of a higher amount of aluminum stearate, 0.4% Run 3 (check) also makes it possible to reduce the clay content by 1.25% ·. Run 2 (check) to 0.25%, Run 3 (check) while maintaining the physical stability of the assembly.

The results in Table I also show that the concomitant use of about 1.6% potassium TPP in a formulation containing 0.5% or 0.3% Pharmagel H, runs 4 and 6, does not adversely affect the physical stability of the formulations. while making it possible to stabilize variations in theological properties over time.

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Notes to Table I

(1) Measured with spindle 4 after three minutes on 24-hour-old samples (2) Measured from height (RT = room temperature = 20 + 2 ° C) (3) Measured by weight (RT = room temperature = 20 + 2 ° C) (4) Liquid separation measured after 6 weeks and 2000 km in a private car (by weight in a plastic bottle).

Example 2

To determine the variations in rheological properties over time, the apparent viscosities of runs 1-7 of Example 1 were measured at 3 rpm and 30 rpm after 1 day, 2 weeks, 4 weeks, 6 weeks and 12 weeks, and the results obtained are shown in Table II below.

The results in Table II show that a 1.5% increase (runs 4, 6 and 7) results in a strong stabilization of variations in rheological properties over time without altering the physical stability of the formulations at 0.3% and 0.5% Pharmagel H clay contents. compared to times 3 (revision) and 5 (revision), which show significant variations in apparent viscosity over time.

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Example 3

The following gel-like thixotropic liquid ADD is prepared following the same general procedures as in Example 1.

Ingredient Amount,% by weight

Sodium silicate (47.5% solution,

Na 2 O: SiO 2 ratio 1: 2.4) 7.48

Monostearyl phosphate 0.16

Dowfax 3B-2 0.36

Thermphos NW 12.0

Thermphos N hexa 12.0

Potassium TPP (50% of active ingredient) 1.6

Aluminum stearate 0.25

Sodium carbonate, anhydrous 4.9

Sodium hydroxide solution (50% NaOH) 6.2

Pharmagel H 1.25

Sodium hypochlorite solution (11%) 1.0

Water remaining pH = 13-13.4

Small amounts of fragrance, color, etc. can also be added to the composition.

The mixture is found to have good thixotropic properties, good stability against phase separation and good stability against variations in theological properties over time.

Example 4

A gel-like thixotropic liquid ADD is prepared as in Example 3 with the change that potassium TPP is replaced by 1.6% (50% active ingredient) potassium pyrophosphate. Similar results are obtained as in Example 3.

Example 5

The following gel-like thixotropic liquid-ADD is prepared following the same general procedures as in Example 1: 28 93553

Ingredient Amount,% by weight

Sodium silicate (47.5% solution,

Na 2 O: SiO 2 ratio 1: 2.4) 7.48

Monostearyl phosphate 0.16

Dowfax 3B-2 0.36

Thermphos NW 12.0

Thermphos N hexa 12.0

Potassium TPP (50% active ingredient) 1.6

Stearic acid 0.4

Sodium carbonate, anhydrous 5.0

Sodium hydroxide solution (50% NaOH) 3.1

Pharmagel H 0.5

Sodium hypochlorite solution (11%) 1.0

Water the rest

Small amounts of fragrance, color, etc. can also be added to the composition.

Example 6

The following gel-like, thixotropic liquid-ADD is prepared following the same general procedures as in Example 1:

Ingredient Amount,% by weight

Sodium silicate (47.5% solution, 7.48

Na 2 O: SiO 2 ratio 1: 2.4)

Monostearyl phosphate 0.16

Dowfax 3B-2 0.36

Thermphos NW 12.0

Thermphos N hexa 12.0

Potassium TPP (50% active ingredient) 1.6

Becheic acid 0.2

Sodium carbonate, anhydrous 5.0

Sodium hydroxide solution (50% NaOH) 6.2

Pharmagel H 0.5

Sodium hypochlorite solution (11%) 1.0

Water remaining 29 93553

Small amounts of fragrance, color, etc. can also be added to the composition.

It is to be understood that the foregoing detailed description is provided for illustrative purposes only and is subject to change without departing from the spirit of the present invention.

Claims (26)

1. Aqueous thixotropic liquid detergent mixture for dishwasher, characterized in that it contains 0.1-0.5% by weight of clay as thixotropic agent, 0.5-3.0% by weight of potassium polyphosphate, 0.1-0 5% by weight metal salt of at least one long chain fatty acid, wherein potassium polyphosphate and metal salt of fatty acid improve the physical stability and stability of the mixture against variations in the rheological properties with time, water and at least some additives selected in the group consisting of organic detergents, pH modifiers, chlorine bleach aids in detergents, sequestering agents, anti-foaming agents, frying particles and mixtures thereof. 2. A composition according to claim 1, characterized in that said mixture contains at least one of the group consisting of potassium tripolyphosphate, potassium pyrophosphate and potassium hexametaphosphate. 3. A composition according to claim 1, characterized in that said mixture contains potassium tripolyphosphate. A mixture according to claim 1, characterized in that the metal salt consists of a polyvalent metal salt formed from a long chain fatty acid containing about 8-22 carbon atoms, or a mixture of one or more such fatty acids, and a metal of group II, III. and IV of the periodic system of the elements. 5. A mixture according to claim 1, characterized in that it. polyvalent metals are aluminum, zinc, calcium or magnesium. 6. A composition according to claim 1, characterized in that the metal salt of fatty acid is aluminum stearate, potassium stearate or magnesium stearate. 93553 35 Detergent composition for automatic dishwashers according to claim 1, characterized in that it contains approximately calculated by weight: (a) 5-35% sodium tripolyphosphate; (b) 2.5-20% sodium silicate, (c) 0-9% alkali metal carbonate; (d) 0.1-5% stable, water dispersible, organic active detergent substance which is stable with respect to pd chlorine bleaching; (e) 0-5% foam reducing agent which is stable with respect to chlorine bleaching; (f) an amount of chlorine bleaching compound which produces about 0.2-4% usable chlorine; (g) 0.1-5% clay in the form of a thixotropic thickener to give the mixture a thixotropy index of about 2-10; (h) 0-8% sodium hydroxide; (i) 0.5-3.0% of at least one of the group consisting of potassium tripolyphosphate, potassium pyrophosphate and potassium hexametaphosphate; (j) 0.1-0.5% of a polyhydric metal salt of a low-chain fatty acid; and (k) the ethereal water. A mixture according to claim 7, characterized in that the stabilizer contains potassium tripolyphosphate. A mixture according to claim 7, characterized in that the stabilizer contains potassium pyrophosphate. 10. A mixture according to claim 7, characterized in that the stabilizer contains potassium hexametaphosphate. A mixture according to claim 7, characterized in that the metal salt stabilizer is a polyvalent metal salt of an aliphatic fatty acid containing about 8-22 carbon atoms. 93553 36 A mixture according to claim 7, characterized in that the acid contains about 12-18 carbon atoms. Mixture according to claim 7, characterized in that the metal salt stabilizer is an aluminum salt or zinc salt of said fatty acid. Mixture according to claim 7, characterized in that the metal salt stabilizer is aluminum stearate. Mixture according to claim 7, characterized in that the metal salt stabilizer is zinc stearate. Mixture according to claim 7, characterized in that the thixotropic thickener (g) is an inorganic colloid forming clay. Detergent composition for automatic dishwashers according to Claim 1, characterized in that it contains approximately by weight: (a) 5-35% sodium tripolyphosphate; (b) 2.5-20% sodium silicate; (c) 0-9% alkali metal carbonate; (d) 0.1-5% in water dispersible active detergent substance which is stable to chlorine bleaching; (e) 0-5% foam reducing agent which is stable to chlorine bleaching; (f) an amount of chlorine bleaching compound which produces about 0.2-4% usable chlorine; (g) 0.1-0.5% clay as thixotropic thickener to give the mixture a thixotropy index of about 2-10; (h) 0-8% sodium hydroxide; (i) 0.5-3.0% potassium polyphosphate; (j) 0.1-0.5% of a polyvalent metal salt of an aliphatic fatty acid containing 12-18 carbon atoms; and (k) the ethereal water. II 93553 37 A mixture according to claim 17, characterized in that it contains potassium tripolyphosphate. Mixture according to claim 17, characterized in that it contains potassium pyrophosphate. A mixture according to claim 17, characterized in that the metal salt stabilizer is an aluminum salt or zinc salt of said fatty acid. Mixture according to claim 17, characterized in that the metal salt stabilizer is aluminum stearate. 22. A composition according to claim 17, characterized in that the metal salt stabilizer is zinc stearate. 23. A composition according to claim 17, characterized in that it contains 0.2-0.4% by weight of clay, 0.8-2.0% by weight of potassium polyphosphate and 0.2-0.4% by weight of metal salt of fatty acid. Composition according to claim 17, characterized in that the thixotropic thickener (g) is an inorganic, colloid-forming clay. 25. A method for cleaning dishes in an automatic dishwasher, characterized in that the dishes in the automatic dishwasher are contacted with an aqueous washing bath, in which an active amount of the mixture according to claim 7 is dispersed. Method for cleaning dishes in an automatic dishwasher, characterized in that the dishes in the automatic dishwasher are contacted with an aqueous washing bath, in which an active amount of the mixture according to claim 17 is dispersed.