CH677931A5 - - Google Patents

Description

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description

The invention relates to a gel-like, thixotropic, aqueous, liquid detergent suitable for dishwashers with improved film-preventing properties and to commercial processes for using the detergent for cleaning dishes, glassware, porcelain and the like.

The agent according to the invention contains water,

at least one component from the group consisting of organic surfactant, bleach, builder, sequestering agent, foam inhibitor and mixtures thereof,

- 0.5 to 5% silica as a film-preventing agent and

- A sufficient amount of a thixotropic thickener, which ensures a thixotropy index of 2.5 to 10.

The dishwashing detergent according to the invention reduces the formation on dishes, glassware, porcelain and the like, especially in hard water, and remains sta-bit against phase separation.

The cleaning agents do not require the addition of a rinse aid, are stable when stored, do not settle and are easily redispersible and pourable.

The agent according to the invention is a thixotropic aqueous suspension of improved physical stability. The thixotropic thickener is preferably a long-chain fatty acid, a metal salt of fatty acids and additionally clay. This thickener enables the formation of stable, gel-like, liquid suspensions which are suitable for use as liquid detergents in automatic dishwashers.

The agent according to the invention has improved properties with regard to the prevention of film formation and physical stability, is readily dispersible in the washing medium and ensures effective cleaning of dishes, glass, porcelain and the like.

The commercially available powder detergents for household dishwashing machines have numerous disadvantages: e.g. a non-uniform composition; costly manufacturing processes; the tendency to cake when stored in a humid environment, resulting in the formation of lumps which are difficult to disperse; Dustiness, a source of particular irritation for allergy sufferers; as well as the tendency to cake in the distribution compartment of the dishwasher. Dishwashing detergents in liquid form, however, cannot generally be used in automatic dishwashers because of their high degree of foaming, their unacceptably low viscosities and excessively strong alkalinity.

In addition, current powder detergents often require the separate hand wiping and drying of dishes, glassware, porcelain and the like to avoid leaving unwanted traces or a film of precipitated calcium and magnesium salts. The use of liquid detergents brings other problems. The builder salts settle on storage and are not easily redispersed. The compositions also often thicken during storage and are not easy to pour.

Recent research and development has focused on the gel or "thixotropic" form of such compositions; however, these compositions have generally not been found to be sufficiently viscous to remain stuck in the dishwasher compartment and also result in stained residues on dishes, glass, porcelain and the like. Ideally, thixotropic cleaning agents should be highly viscous at rest, have a Bingham-plastic character and have relatively high flow limits. If, however, they are subjected to shear forces, for example shaken in a container or squeezed through an opening, they should fluidize quickly and quickly return to the state of high viscosity / Bingham plasticity when the applied shear stress ceases. Stability is also of primary importance, i.e. after standing for a long time, there should be no significant phase separation or leakage.

For effective use, it is generally recommended that the detergent used in automatic dishwashers (also known as ADD) contains the following substances:

1) sodium tripolyphosphate (NaTPP) to soften or bind the water-hardening minerals and to emulsify and / or peptize the dirt;

2) Sodium silicate to create the alkalinity required for effective cleaning and to protect the glaze and pattern of fine porcelain;

3) sodium carbonate, optionally to increase alkalinity;

4) a chlorine-releasing substance to help eliminate stains that cause water stains; and

5) Defoamer / surfactant to reduce foam, which increases the efficiency of the machine and increases the cleaning power required.

See, for example, SDA Detergents in Depth, “Formulations Aspects of machine Dishwashing”, Thomas Oberle (1974). Detergents close to the compositions described above,

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are mostly liquids or powders. In general, hypochlorite bleach is omitted from these compositions because it tends to react with other chemically active ingredients, particularly surfactants, degrading the suspending or thixotropic agent and impairing its effectiveness.

For example, US Pat. No. 3,985,668 scrubbing agents are described as having a gel-like consistency and containing (1) suspending agents, preferably types of smectite and attapulgite; (2) polishing agents, e.g. Silica sand or pearlite; and (3) filler made of powdery low density polymer, expanded pearlite and the like, which has buoyancy and thus has a stabilizing effect on the composition, in addition to giving bulk and thereby replacing water, which would otherwise result in unwanted protruding layer formation due to leakage and Phase destabilization becomes available. The above are the essential components. Optional ingredients include hypochlorite bleach, bleach resistant surfactant and buffer, e.g. Silicates, carbonates and monophosphates. As further optional components, builders such as NaTPP can be incorporated in order to supplement the builder function which is not performed by the buffer, the amount of such builders according to the patent not exceeding 5% of the composition. The buffer / builder components maintain the desired (greater than) pH 10 values. A high pH is said to minimize the decomposition of the chlorine bleach and the undesirable interaction between surfactant and bleach. As indicated, NaTPP, if present, is limited to 5%. Foam killers are not specified.

GB 2 116 199A and GB 2 140 450A disclose liquid detergents which can be used in automatic dishwashers, the desired properties of which are characterized as a thixotropic gel-like structure and which contain all of the various constituents which are required for effective cleaning in an automatic dishwasher. The normally gel-like, aqueous composition which can be used in dishwashers and has thixotropic properties comprises, on a weight basis, the following components:

(a) 5 to 35% alkali tripolyphosphate;

(b) 2.5 to 20% sodium silicate;

(c) 0 to 9% alkali carbonate;

(d) 0.1 to 5% chlorine bleach-resistant, water-dispersible organic cleaning active material (surfactant);

(e) 0 to 5% chlorine bleach resistant foam damper;

(f) chlorine bleach in an amount of about 0.2 to 4% available chlorine;

(g) thixtropic thickener in an amount sufficient to provide the composition with a thixotropic index of about 2.5 to 10; and

(h) Sodium hydroxide if necessary to adjust the pH.

Detergents formulated in this way that can be used in automatic dishwashers are low-foaming, readily soluble in the washing medium and most effective at pH values which are best suited for improved cleaning action, namely pH 10.5 to 13.5. The compositions are usually of a gel-like consistency, i.e. a highly viscous, opaque gelatinous material with a Bingham-plastic character and thus relatively high flow limits. As a result, a certain shear force is necessary to initiate or increase the flow, as is obtained, for example, in the moving distribution unit of an automatic dishwasher that is in operation. Under such conditions, the composition is quickly fluidized and easily dispersed. If the shear force is interrupted, the fluid composition quickly returns to a highly viscous, Bingham-plastic state that closely approximates its previous consistency.

US Pat. No. 4,511,487 describes a low-foaming detergent paste for dishwashers. The composition is based on a mixture of finely divided hydrated sodium metasilicate, an active chlorine compound and a thickener, which is a leafed silicate of the hectorite type. A small amount of nonionic surfactants and alkali carbonates and / or hydroxides can be used.

German patent application P 3 644 795 describes a thixotropic, aqueous cleaning agent which can be used in automatic dishwashers and which contains a long-chain fatty acid as a thixotropic thickener.

The thixotropic, aqueous, liquid detergents of the invention overcome numerous problems of previous powder or liquid detergents. The fact that a small but effective amount of a film-preventing silica agent, namely 0.5-5%, is added to the composition means that a rinse aid is not required and also no wiping or drying with a cloth to dry clean dishes, glassware, cups and get eating utensils. The thixotropic, aqueous, liquid dish detergent also has the advantages that it is stable, does not settle when stored and is easily redispersible. The liquid compositions of the invention are easy to pour, easy to measure and easy to put into the dishwasher.

Another and surprising advantage of adding the film-forming preventing agent to the cleaning agent is that the silica causes brown spots to form in the dishes.

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dishwasher prevented. Brown spots are formed by the deposition of iron and / or manganese oxides in the dishwasher. The formation of brown spots is a serious problem in areas with hard water. The silica present in the formulation acts on the iron and / or manganese in the wash water and prevents their deposition in the dishwasher as iron and / or manganese oxides.

It is an object of the invention to provide a thixotropic, aqueous, liquid cleaning agent which can be used in automatic dishwashers and has improved properties for preventing film formation.

Another object of the invention is to provide a thixotropic, aqueous, liquid detergent that is stable in storage, easy to pour and easily dispersible in the dishwashing water.

Another object of the invention is to provide a commercial process for washing dishes, glass, porcelain and the like in an automatic dishwasher, using a thixotropic, aqueous, liquid cleaning agent in which a separate washing aid additive is not added or required.

Yet another object of the invention is to provide a commercial process for washing dishes, glass, porcelain and the like in an automatic dishwasher using an aqueous liquid detergent, the dishes, glass, porcelain and the like being in the machine can be dried without leaving any traces or film.

Finally, it is also an object of the invention to provide stable thixotropic, aqueous, liquid compositions, in particular cleaning agents which can be used in dishwashers, by incorporating a small effective amount of a film-preventing silica agent, namely 0.5-5%, into the aqueous suspension.

The agent according to the invention also contains a sufficient amount of a thixotropic thickener, preferably a fatty acid, the metal salt of a fatty acid and / or clay, in order to inhibit the settling of the suspended particles and to prevent phase separation. The physical stability is above all due to the addition of a fatty acid , the metal salt of a fatty acid and / or clay improved as a thixotropic thickener. The silica contained in the agent according to the invention usually has a particle size of 0.1-10 micrometers. The thixotropic thickener, which ensures a thixotropy index of 2.5-10, primarily prevents the suspended particles from settling, e.g. Alkali builder salts.

A preferred agent according to the invention contains on a weight basis

(a) 5 to 35% alkali tripolyphosphate;

(b) 2.5 to 40% sodium silicate;

(c) 0.5 to 5% silica as a film preventing agent;

(d) 0 to 9% alkali carbonate;

(e) 0.1 to 5% chlorine bleach resistant, water dispersible organic cleaning active material;

(f) 0 to 5% chlorine bleach resistant foam damper;

(g) chlorine bleach in an amount of 0.2 to 4% available chlorine;

(h) thixotropic thickener in an amount sufficient to ensure a thixotropy index of 2.5 to 10;

(i) 0 to 8% sodium hydroxide; and

(j) water as rest.

According to this aspect, the invention also provides a commercial method for cleaning dishes in an automatic dishwasher using an aqueous washing bath which contains an effective amount of the liquid dishwasher detergent (LADD) suitable for automatic dishwashers, as described above. According to this aspect, the dishwashing detergent can be easily poured into the distributor compartment of the dishwasher and within a few seconds it quickly thickens to its normal gelatinous or pasty state, in which it remains safely in the distributor compartment, until shear forces act on it again, such as, for example, from spray water from the dishwasher .

In the following the invention will be described in more detail by means of special training methods.

The dishwashing detergents, for example in accordance with GB 2 116 199A and GB 2 140 450A, show theological properties, which was determined by testing the product viscosity as a function of the shear rate. The compositions exhibited higher viscosity at a low shear rate and lower viscosity at a high shear rate, the data indicating efficient fluidization and gelation well within the shear rates that exist within standard automatic dishwashers. This means practically improved flow and working properties as well as less leakage in the machine's compartment compared to previous liquid or gel detergents for automatic dishwashers. With applied shear rates corresponding to 3 to 30 rpm, the viscosities (Brookfield) were accordingly in the range from 10,000 to 30,000 mPa.s. up to about 3000 to 7000 mPa.s., which after 3 minutes at room temperature using an LVT Brookfield viscometer

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was determined using a No. 4 spindle. A shear rate of 7.4 seconds corresponds to a spindle rpm of approximately 3. An approximately 10-fold increase in the shear rate produces an approximately 3 to 9-fold reduction in viscosity. The applicant's older compositions thus have threshold fluidizations at lower shear rates and to a significantly greater extent, expressed as a proportionate increase in shear rate or shear rate versus proportionate decrease in viscosity. This property of applicant's earlier products has been summarized with the term thixotropy index (TI), which represents the ratio of the apparent viscosity at 3 rpm and at 30 rpm. The previous compositions have a TI of 2 to 10. The detergents to be used in automatic dishwashers should clearly and quickly return to the consistency of the previous idle state when the shear force is interrupted.

As for the apparent viscosity, it was found that as long as the viscosity at room temperature (di 22 ° ± 1 ° C) measured in a Brookfield HATD viscometer using a No. 4 spindle at 20 rpm, was less than about 20,000 mPa. s. is that the composition can be easily shaken so that a thixotropic composition can be easily "fluidized" or "liquefied" and it is possible that the product is distributed through a conventional squeeze tube or other known distributor.

The invention is based on the surprising discovery that significantly improved film-preventing properties are achieved if a small but effective amount of silica or silicon dioxide is added to the thixotropic, aqueous, liquid cleaning agent as a film-preventing agent. The physical stability, i.e. Resistance to phase separation, settling, etc. can be achieved by adding a small but effective amount of a thixotropic thickener and stabilizer to the composition.

The materials that can be used as film-preventing silicas are “evaporated” or “evaporated” (fumed) or precipitated synthetic or natural silicas or silicon dioxide. The silica can be amorphous or crystalline.

The silica material used can contain up to about 0.1 to 5% alumina (Al2O3), usually up to about 0.5 to 3% and especially about 1% alumina, based on the weight of the silica.

A preferred silica material is Syloid® 244, an amorphous silica that has a particle size of about 4 microns and is available from W.R. Grace Co. is available. Another suitable silica material is Siiox® 15, also from W.R Grace Co., which has a particle size of about 4 micrometers.

Another preferred silica material is "Huber Zeo 49", an amorphous silica from J.M. Huber Corporation, which contains about 1% alumina (AI2O3). The presence of as little as 1% Al2O3 has been found to help reduce the hydrolysis and consequent solubility of the silica in the strongly alkaline detergents suitable for dishwashers.

The particle size of the silica material used is essential in order to achieve the desired film-preventing properties.

The silica particles used are finely divided and can have a particle size of about 0.10 to 10, preferably 0.50 to 8 and particularly preferably about 1.0 to 5.0 micrometers. The silica particles of this size and the amount used here are not rubbing or grinding.

The fine-particle silica particles cause the coagulation of proteinaceous, particulate dirt in dishwashing and keep it in suspension to prevent it from settling on clean glass and dishes.

The amount of silica as a film-preventing agent that can be used to achieve the desired improvement in film formation depends on the hardness of the water, the surfactant, inorganic salts and other components of automatic dishwashing detergents. The film-preventing agent is particularly effective in hard water of hardness, for example, 300 ppm or more.

The silica used as a film-preventing substance in an amount of 0.5 to 5, preferably 1 to 4 and particularly preferably from 1.5 to 3 wt .-%, based on the weight of the entire composition.

The thixotropic thickeners or suspending agents which are contained in the composition according to the invention in order to impart thixotropic properties to the aqueous medium can be, for example, fatty acid, polyvalent fatty acid salts or inorganic colloid-forming clays. The thixotropic thickeners are said to be resistant to strong alkalinity as well as to chlorine bleaches such as sodium hypochlorite. The preferred thixotropic thickeners include the fatty acids, the salts of polyvalent metals of fatty acids and the inorganic, colloid-forming clays of the smectite and / or attapulgite types. The amount of thixotropic thickener used depends on the particular thickener used, but sufficient thickener must be added to the formulation to give the composition a thixotropic index of 2.5 to 10.

The preferred thixotropic fatty acid thickeners are the higher aliphatic fatty monocarboxylic acids with 8 to 22, particularly preferably 10 to 20 and in particular 12 to 18 carbon atoms.

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finally the carbon atom of the carboxyl group of the fatty acid. The aliphatic radical can be saturated or unsaturated, straight-chain or branched. Straight chain saturated fatty acids are preferred. Fatty acid mixtures can be used, such as the naturally occurring ones, for example tallow fatty acid, coconut fatty acid, soy fatty acid etc. or the synthetic fatty acids from industrial production processes.

Examples of fatty acids that can be used as thickeners include e.g. Decanoic acid, lauric acid, dodecanoic acid, palmitic acid, myristic acid, stearic acid, oleic acid, eicosanoic acid, tallow fatty acid, coconut fatty acid, soy fatty acid and mixtures thereof. Stearic acid and mixed fatty acids, e.g. Coconut fatty acid are preferred.

The amount of fatty acid thickener to achieve the desired thixotropy values and physical stability depend on such factors as the type of fatty acid, the surfactant, the inorganic salts, in particular TPP, on other components of the dishwashing detergent for automatic dishwashers (LADD) and on the expected ones Storage and shipping conditions.

In order to ensure the desired long-term stability and the non-occurrence of phase separation, however, amounts of fatty acid thixotropic agent in the range of 0.03 to 5, preferably 0.03 to 0.2, particularly preferably 0.05 to 0.15% can generally be used will.

The salts of the above fatty acids with polyvalent metals can also be used as thixotropic thickeners for the compositions according to the invention. Metal salts suitable as thixotropic thickeners are disclosed in USSN 903 924 (1986).

The preferred metals are the multivalent metals such as magnesium, calcium, aluminum and zinc.

In general, the metals can be present in the divalent to pentavalent state. The metal salts are preferably used in the higher oxidation states of the metals. The choice of the metal salt for the dishwashing detergent which can be used in the dishwashing machine should, of course, be the same as in old other applications in which the composition according to the invention comes into or may come into contact with objects, which are used for handling, storage or for offering food or in some other way Human or animal come into contact or can be consumed by them with regard to the toxicity of the metal. For this reason, calcium and magnesium salts are particularly preferred since they are generally considered safe food additives.

Many of these metal salts are commercially available. For example, the aluminum salts are obtained in the triacid form, e.g. Aluminum stearate as aluminum tristearate, Al (Ci7H3sCOO) 3. The mono acid salts, e.g. Aluminum monostearate, Al (OH) 2 (Ci7H3sCOO) and the diacid salts, e.g. Aluminum distearate AI (OH) (Ci7H35COO) 2 and mixtures of two or three of the mono-, di- and tri-acid salts can be used with metals such as aluminum which are trivalent (+3); Mixtures of the mono- and diacid salts can be used with divalent metals such as Zn, which are divalent (+2). It is particularly preferred that the diacids of the + 2-valent metals and the triacids of the + 3-valent metals, the tetra acids of the + 4-valent metals and the pentacids of the + 5-valent metals are used in predominant amounts. For example, at least 30, preferably at least 50, particularly preferably at least 80 to 100% of the total metal salts should be in the highest possible oxidation state, i.e. each of the possible valences is said to be occupied by a fatty acid residue.

As mentioned above, the metal salts are generally commercially available; however, they can be easily prepared, for example by saponification of a fatty acid, e.g. of animal fat, stearic acid etc., or the corresponding fatty acid ester, and subsequent treatment with a hydroxide or oxide of the polyvalent metal, in the case of the aluminum salt for example with aluminum, aluminum oxide 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 the preferred fatty acid salt stabilizers of polyvalent metals. Mixed fatty acid metal salts as well as the naturally occurring acids, e.g. Coconut acid, as well as the mixed fatty acids from industrial manufacturing processes are used with advantage as an inexpensive and yet effective source of the long-chain fatty acid.

The amount of fatty acid salt stabilizers used to achieve the desired increase in physical stability depends on such factors as the type of fatty acid salt, the type and amount of thixotropic substance, the surfactant, the inorganic salts, especially TPP, other components of the dishwasher detergent and the expected Storage and shipping conditions.

In general, however, amounts of fatty acid salt of polyvalent metals as stabilizing agents in the range from 0.02 to 1, preferably 0.06 to 0.8, particularly preferably 0.08 to 0.4% ensure the long-term stability and the non-occurrence of phase separation when standing or during transportation at both low and elevated temperatures as required for a product to be accepted commercially.

Conventional inorganic thixotropic clay thickeners can also be used in the compositions according to the invention. The clay thickeners can be used in small amounts in combination with the fatty acid thickeners or in combination with the fatty acid salts used as thickeners

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Metals are used. However, the clay thickeners can be used as such as thixotropic thickeners.

The preferred clay thickeners comprise the inorganic, colloid-forming clays of the smectite and / or attapulgite types.

Smectite clays include montmorillonite (bentonite), hectorite, attapulgite, SmeGtit, saponite and the like. Montmorillonite clays are preferred and are available under trade names such as "Thixogel" ® No. 1 and "Gelwhite" ® GP, H, etc. from Georgia Kaolin Company; and under the trade name "Eccagum" ® GP, H etc. from Luthern Clay Products. Attapulgite clays comprise the materials which are commercially available under the trade name "Attagei" ®, ie Attagel 40, Attagel 50 and Attagel 150 from Engelhard Minerals and Chemicals Corporation. Mixtures of smectite and attapulgite types in weight ratios of 4/1 to 1 / 5, thickeners or suspending agents of the above types are known and are described, for example, in U.S. Patent 3,985,668. Abrasives or polishing agents should be avoided in the LADD compositions as they damage the surface of fine dishes, crystal and the like can.

When used in combination with the fatty acids or the fatty acid salts of polyvalent metals, the thixotropic clay thickeners are used in amounts of 0.1 to 3, preferably 0.1 to 2.5 and particularly preferably 0.1 to 2%.

When the thixotropic clay thickeners are used alone as the thixotropic agent, they can be used in amounts of 1.5 to 8, preferably 2 to 5%, based on the weight of the formulation.

In general, LADD effectiveness is directly dependent on (a) the available chlorine levels; (b) alkalinity; (c) the solubility in the washing medium; and (d) foam inhibition. It is preferred that the pH of the LADD composition be at least about 9.5, more preferably about 10.5 to 13.5, and most preferably at least about 11.5. At the relatively lower pH values, the LADD product is too viscous, i.e. similar to solids, and is therefore not readily fluidized under the shear forces generated within the manifold compartment under normal operating conditions. The addition of NaOH is often necessary in order to increase the pH so that it is within the ranges indicated above and to increase the flowability. In the compositions according to the invention, the presence of carbonate is also often required, since it acts as a buffer and helps maintain the desired pH. Excess carbonate should, however, be avoided since it can cause the formation of needle-like carbonate crystals, which affects the stability, thixotropy and / or washing power of the LADD product, as well as the distributability of the product, for example from squeeze bottles. Furthermore, caustic soda (NaOH) serves to neutralize the phosphorus or phosphonic acid ester that may be present as a foam damper. Usually about 0.5 to 3% by weight of NaOH and about 2 to 9% by weight of sodium carbonate are added to the LADD composition, although it should be noted that sufficient alkalinity can be achieved with the NaTPP and sodium silicate.

The NaTPP can be used in the LADD composition in a range of 8 to 35, preferably about 20 to 30% by weight and should preferably be free of heavy metal which has a tendency to decompose or add to the preferred sodium hypochlorite and other chlorine bleaching agents inactivate. The NaTPP can be anhydrous or hydrated and can comprise the stable hexahydrate with a degree of hydration of 6 corresponding to about 18% by weight of water or more. In fact, because of the stability of the hexahydrate, the presence of a certain amount of water of hydration is highly effective, since it presumably forms nuclei of the stable hexahydrate, which promote the hydration and solubilization of the remaining NaTPP particles. If only the hexahydrate is used, the product can become too liquid. Conversely, if only the anhydrous NaTPP is used, the product may become too thick and therefore unsuitable. Particularly preferred LADD compositions are obtained, for example, if a weight ratio of 0.5 / 1 to 2/1 of anhydrous / hexahydrated NaTPP is used, values of about 1/1 being particularly preferred.

Foam inhibition is essential to increasing the efficiency of the dishwasher and minimizing the destabilizing effects that can occur in the presence of excess foam within the appliance during use. The foam can be reduced sufficiently by a suitable choice of the type and / or amount of the surfactant, which is the main foam-producing component. The degree of foaming also depends somewhat on the hardness of the washing water in the machine, so that an appropriate adjustment of the proportions of NaTPP, which has a water softening effect, can help to achieve the desired level of foam inhibition. In general, however, it is preferred to incorporate a chlorine bleach resistant foam damper or inhibitor. The alkylphosphonic acid esters of the formula are particularly effective

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HO — P R

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which are available from BASF Wyandotte (PCUK-PAE), and especially the acidic alkyl phosphate esters of the formula

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HO-P -OR

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which are available, for example, from Hooker (SAP) and Knapsack (LPKN-158), in which one or both R groups in leather esters can independently be a Cte to Cao alkyl group. Mixtures of these two types or any other chlorine bleach-resistant types or mixtures of mono- and diesters of the same type can be used. A mixture of acidic mono- and di-gra- to cis-alkyl phosphate esters, for example acidic monostearyl / distearyl phosphates 1.2 / 1 (Knapsack), is particularly preferred. If they are used, the foam silencers are usually used in amounts of 0.01 to 5, preferably 0.1 to 5, particularly approximately 0.1 to 0.5%, the weight ratio of surfactant to foam silencer generally being approximately 10% / 1 to 1/1 and preferably about 4/1 to 1/1. Other applicable defoaming agents include, for example, the known silicones.

Although any chlorine bleach is applicable in the compositions of the invention, such as dichloroisocyanurate, dichlorodimethylhydantoin or chlorinated TSP, alkali, e.g. Potassium, lithium, magnesium and especially sodium hypochlorite are preferred. The composition is said to contain a sufficient amount of chlorine bleach to provide about 0.2 to 4.0 weight percent chlorine, as determined, for example, by acidifying 100 parts of the composition with excess hydrochloric acid. A solution containing about 0.2 to 4.0% by weight sodium hypochlorite contains (roughly) the same percentage of available chlorine. A solution with about 0.8 to 1.6% by weight sodium hypochlorite contains about 0.8 to 1.6% by weight available chlorine and is particularly preferred. For example, sodium hypochlorite (NaOCl) solution with about 11 to about 13% of available chlorine in amounts of about 3 to 20, preferably about 7 to 12% can be used with advantage.

The sodium silicate, which ensures alkalinity and protection of hard surfaces such as glaze and pattern of fine porcelain, is used in an amount of about 2.5 to 40, preferably about 10 to 35% by weight in the composition. The sodium silicate also protects the washing machine against corrosion. At the higher concentrations given here, for example at concentrations above about 10% by weight, the silicate also ensures an improved stain-preventing effect. The sodium silicate is usually added in the form of an aqueous solution which preferably has a NaaO / SiOa ratio of about 1 / 2.2 to 1 / 2.8, for example 1 / 2.4. Most of the other components of the composition, especially NaOH, sodium hypochlorite and the foam suppressor can also be added in the form of an aqueous dispersion or solution.

The surfactant used in the compositions according to the invention must be stable in the presence of chlorine bleach, especially hypochlorite bleach. Preferred are the anionic, amine oxide, phosphine oxide, sulfoxide or betaine surfactants which are water dispersible, with the anion surfactants mentioned first being most preferred. They are used in amounts in the range of about 0.1 to 5, preferably about 0.3 to 2.0%. The surfactants which are particularly preferred for the invention are the linear or branched alkali mono- and / or di (Cs to Ci4) alkyl diphenyl oxide mono- and / or disulfonates, which are commercially available, for example, under the trade names “DOWFAX” ®, e.g. DOWFAX 3B-2 and DOWFAX 2A-1.

In addition, the surfactant should be compatible with the other components of the composition. Other suitable surfactants include the primary alkyl sulfates, alkyl sulfonates, alkyl aryl sulfonates and secondary alkyl sulfates. Examples are sodium Cio to Cß-alkyl sulfates such as sodium dodecyl sulfate and sodium tallow alcohol sulfate, * sodium Cio to cis alkane sulfonates such as sodium hexadecyl 1-sulfonate and sodium tri-Ci2 to cis alkylbenzenesulfonates such as sodium dodecylbenzenesulfonates. The corresponding potassium salts can also be used.

As further suitable surface-active substances or surfactants, the amine oxide surfactants of the structure RaRiNO are typical, in which each R has a lower alkyl group such as e.g. Is methyl and R1 is a long alkyl radical of 8 to 22 carbon atoms, e.g. a lauryl, myristyl, palmityl or cetyl group stands in place of an amine oxide surfactant a corresponding phosphine oxide R2RIPO or Sul-

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foxid RR1SO are used. Betaine surfactants usually have the structure R2R1NR "COO ~, in which each R denotes a lower alkylene group having 1 to 5 carbon atoms. Specific examples of these surfactants are lauryldimethylamine oxide, myristyldimethylamine oxide, the corresponding phosphine oxides and sulfoxides and the corresponding betaines including dodecyldimethylammonium acetate, tetradecylanoethylatonamethylammonium hexamethylammonium hexamethyl ammonium etc. For reasons of biodegradability, the alkyl groups in these surfactants are said to be linear, such compounds are preferred.

Surfactants of the type specified above are known and are described, for example, in US Pat. Nos. 3,985,668 and 4,271,030.

The amount of water contained in these compositions should of course not be so great that an unacceptably low viscosity and high fluidity is produced, nor so low that an unacceptably high viscosity and low flowability is generated, in any case the thixotropic properties being reduced or destroyed . This amount is easily determined by routine experiments in each individual case and is generally about 25 to 75, preferably about 50 to 65% by weight. The water should also preferably be demineralized and softened. These amounts of water in the composition include the water added as part of the liquid solutions of other ingredients, but include unbound water such as that in NaTPP hexahydrate.

Other conventional ingredients can be incorporated into these compositions in small amounts, which are generally less than 3% by weight, such as, for example, perfume, hydrotropes such as sodium benzene, toluene, xylene and cumene sulfonates, protective substances, dyes and Pigments and the like, which of course all have to be resistant to chlorine and high alkalinity (properties of all components). The chlorinated phthalocyanines and polysulfides of aluminum silicate, which in each case provide pleasant green and blue tints, are particularly preferred as the coloring substance.

The liquid ADD compositions of the invention are usually used in a simple manner known per se for washing dishes, glassware, cups, eating utensils and the like in an automatic dishwasher equipped with a suitable dishwasher detergent dispenser in an aqueous washing bath which contains an effective amount of the Contains composition.

According to a preferred embodiment of the invention, the aqueous, liquid composition for cleaning dishes is formulated using the ingredients specified below.

component

Percent by weight

Alkali tripolyphosphate

10 to 25

Sodium silicate (47.5%)

15 to 40

preventing film

1 to 4

Silica agent

Alkali carbonate (anhydrous)

2 to 8

chlorine-proof, water-dispersible

0.5 to 3

organic active cleaning material (surfactant)

chlorine bleach resistant foam damper

0.10 to 3

Sodium hypochlorite, bleach

0.2 to 4

Fatty acid as a thixotropic thickener

0.03 to 0.5

Sodium hydroxide (50%)

2 to 6

Water as rest

-

The thixotropic, aqueous, liquid detergents of the invention which can be used in automatic dishwashers can contain customary additives for dishwashing detergents. The formulations can be made with commercially available solid powder builders and / or the ingredients can be mixed and the formulations milled to a desired particle size.

The invention can be implemented in various ways; some specific training methods are described in the attached examples.

All amounts and ratios are based on the weight of the composition unless otherwise stated.

example 1

A thixotropic, aqueous, liquid detergent suitable for dishwashing machines was produced from the components and amounts given below.

9

5

10th

15

20th

25th

30th

35

40

45

50

55

60

65

CH 677 931 A5

Component weight percent

Demineralized water 26.26

Knapsack LPKN-158 foam damper ^ 0.16

Sodium hydroxide (50%) 5.00

Sodium carbonate (anhydrous) 5.00

Sodium tripolyphosphate (anhydrous) 20.00

Silicic acid as film-preventing agent 2.00 Stearic acid as thixotropic thickener 0.10

Dowfax 3B-2 as Tensid® 0.80

Sodium hypochlorite (11%) 9.10

Sodium silicate (1 / 2.23.47%) 31.58

100.00

^ Mixture of mono- and distearyl (Cie to Ci8) alkyl esters of phosphoric acid, molar ratio 171.3.

® silica Syloid 244 has a particle size of about 4 microns and is from W.R. Grace Co. available.

® sodium mono- and didecyldiphenyl ether sulfonate (45% solution).

The stearic acid was melted and the ingredients were added to the water generally in the order given and stirring was gently until a homogeneous mixture was obtained. The formulation was made by washing glass and dishes at 54.4 ° C in hard water (300 ppm hardness) tested in an automatic dishwasher, the cleaned and dried dishes had no visible film.

Example 2

In order to demonstrate the effect of the addition of the silica used as a film-preventing agent, formulations with and without a film-forming preventing agent were prepared and compared with a commercially available powder-form cleaning agent.

The compositions contained the following ingredients:

component

Silica (A '

No silica'8 '

as a film preventing as a film preventing

agent

agent

Demineralized water

32.05

34.55

Knapsack LPKN-158, foam damper

0.16

0.16

Sodium hydroxide (50%)

5.00

5.00

Sodium carbonate (anhydrous)

5.00

5.00

Sodium tripolyphosphate (anhydrous)

20.00

20.00

Silica (Syloid 244), film-preventing agent

2.50

-

Stearic acid, thixotropic thickener

0.10

0.10

Dowfax 3B-2, surfactant

0.80

0.80

Sodium hypochlorite (11%)

9.10

9.10

Sodium silicate (1 / 2.23; 47%)

25.29

25.29

100.00

The stearic acid was melted and the ingredients were added to the water generally in the order given, stirring gently until a homogeneous mixture was obtained. The formulation was tested by washing glassware at 54.4 ° C in hard water (300 ppm hardness)

The two formulations (A) and (B) above were tested and compared with a commercially available powder-form cleaning agent (C) for dishwashers. The formulations were tested in a Kenmore automatic dishwasher using the method described in ASTM D3566-79

10th

5

10th

15

20th

25th

30th

35

40

45

50

55

60

65

CH 677 931 A5

except that only four cleaning cycles were used. The film and stain values were rated on the following scales;

Film rating scale

1. Best, no visible film

2. Slight, visible film picture

3. Noticeable film, increasingly

4. Continued growth of a significant film

5. The film formation becomes excessive

6. Strong film formation, excessive build-up

7. Continued increase in excessive film education

Spot rating wet scale

A. Best of all, no stains

B. Very few visible spots

C. Clearly

D. Significant coverage about 50%

The results after the 4th gear are summarized in Table I below.

Table 1

Formulation of impact assessment i__ spots film

(A) Film preventing silica agent B-C 1-2

(B) no film-preventing silica agent B-C 5-6

(C) Puiver-shaped commercial product B-C 4-5

Example 3

Thixotropic, aqueous, liquid cleaning agents suitable for dishwashers were formulated from the following constituents in the amounts stated.

11

5

10th

15

20th

25th

30th

35

40

45

50

55

60

65

CH 677 931 A5

component

Silica'1 "^

No silica (E)

as a film preventive as a film preventive

agent

agent

Demineralized water

32.638

34.638

Graphtol, green pigment

0.002

0.002

Knapsack LPKN-158, foam damper

0.160

0.160

Sodium hydroxide (50%)

5,000

5,000

Sodium carbonate (anhydrous)

5,000

5,000

Sodium silicate (1 / 2,35,43,5%)

25,300

25,300

Sodium tripolyphosphate (anhydrous)

20,000

20,000

Silica as anti-fime agent'1 *

2,000

-

Dowfax 3B-2, Tensid®

0.800

0.800

Stearic acid®

0.100

0.100 ■

Sodium hypochlorite (11%)

9,000

9,000

100,000 100,000

Silicic acid (Huber Zeo 49) contains approximately 1% aluminum oxide (AI2O3) and has a particle size of approximately 9 microns.

® sodium mono- and -didecyldiphenyletherdisuifonat (45% solution).

® Emersol 132 from Emery Company.

The stearic acid was melted and the ingredients were added to the water generally in the order given, stirring until a homogeneous mixture was obtained. The formulations were tested by washing glassware at 54.4 ° C in hard water (300 ppm hardness)

The two formulations were tested and compared to a powdery, commercially available detergent (F) for automatic dishwashers. The formulations were tested in a Kenmore automatic dishwasher using the method described in ASTM D3566-79 with the exception that only four cleaning cycles were used. The stain and film formation was evaluated as in Example 2; the results obtained after the fourth cleaning cycle are summarized in Table II below

Table"

Impact assessment

Spots film

(D) Film-preventing silica agent B-C 1-2

(E) no anti-siliceous agent B-C 4

(F) Powdered detergent (commercial product) B-C 5-6

Example 4

A thixotropic aqueous liquid dishwashing detergent for dishwashers was formulated from the following ingredients in the amounts stated:

12

5

10th

15

20th

25th

30th

35

40

45

50

55

60

65

CH 677 931 A5

component

Percent by weight

Demineralized water

38.79

Aluminum stearate, thixotropic thickener

0.25

Clay (Pharmagel H), thixotropic thickener

1.25

Sodium silicate (1 / 2,4,47,5%)

17.73

Sodium tripolyphosphate (anhydrous)

12.00

Sodium tripolyphosphate (hexahydrate)

12.00

Silica agent which prevents film

2.00

Sodium carbonate (anhydrous)

5.00

Sodium hypochlorite (11%)

7.61

Dowfax 3B-2, surfactant

0.80

Foam vapors / 1 '

0.16

Sodium hydroxide (50%)

2.40

Graphitol, green

0.01

100.00

(1) 1/1 mixture of LPKN-158 and PCUK-PAE.

The ingredients were mixed in the usual way or according to the method of German patent application P 3 729 381.

The formulation was tested by washing glassware at 54.4 ° C in hard water (300 ppm hardness) in an automatic dishwasher. The clean and dried glassware was film-free.

The thixotropic, aqueous, liquid, dishwasher-safe detergents of the invention provide improved film properties.

Claims (18)

Claims 1. Containing gel-like, thixotropic, aqueous, liquid detergent suitable for dishwashers -Water, at least one component from the group consisting of organic surfactant, bleach, builder, sequestering agent, foam inhibitor and mixtures thereof, - 0.5 to 5% silica as a film-preventing agent and - A sufficient amount of a thixotropic thickener, which ensures a thixotropy index of 2.5 to 10. 2. Cleaning agent according to claim 1, characterized in that the film-preventing silica is present in an amount of 1 to 4%. 3. Cleaning agent according to claim 1, characterized by a weight-based content of (a) 5 to 35% builder; (b) 2.5 to 40% sodium silicate, (c) 0.5 to 5% film-preventing silica agent having a particle size of 0.1 to 10 microns; (d) 0 to 9% alkali carbonate; (e) 0.1 to 5% chlorine bleach resistant, water dispersible organic surfactant; (f) 0 to 5% chlorine bleach resistant foam damper; (g) chlorine bleach in an amount providing 0.2 to 4% chlorine; (h) a sufficient amount of a thixotropic thickener to ensure a thixotropy index of 2.5 to 10; (i) 0 to 8% sodium hydroxide; 0) water as rest. 4. Cleaning agent according to claim 3, characterized in that the thixotropic thickener comprises a long-chain fatty acid in an amount of 0.03 to 0.5%. 5. Cleaning agent according to claim 3, characterized in that the thixotropic thickener comprises a salt of a polyvalent metal of a long-chain fatty acid in an amount of 0.02 to 1.0%. 6. Cleaning agent according to claim 4, characterized in that it additionally comprises a thixotropic clay thickener in an amount of 0.1 to 3.0%. 7. Cleaning agent according to claim 5, characterized in that it additionally comprises a thixotropic clay thickener in an amount of 0.1 to 3.0%. 13 5 10th 15 20th 25th 30th 35 40 45 50 55 60 65 CH 677 931 A5 8. Cleaning agent according to claim 3, characterized in that the film-preventing silica agent has a particle size of 0.5 to 8.0 microns. 9. Cleaning agent according to claim 1, characterized by a content of (a) 5 to 35% alkali tripolyphosphate; (b) 2.5 to 40% sodium silicate; (c) 1 to 4% film-preventing silica agent having a particle size of 0.5 to 8.0 microns; (d) 0 to 9% alkali carbonate; (e) 0.1 to 5% chlorine bleach-resistant, water-dispersible organic surfactant, (f) 0 to 5% chlorine bleach resistant foam damper; (g) chlorine bleach in an amount providing 0.2 to 4% chlorine, (h) a sufficient amount of a thixotropic thickener to have a thixotropy index of 2.5 to 10 to guarantee, (i) 0 to 8% sodium hydroxide; and (j) water as rest. 10. Cleaning agent according to claim 8, characterized in that the film-preventing silica agent contains 0.1 to 5% aluminum oxide, based on the weight of the silica. 11. Cleaning agent according to claim 8, characterized in that the silica has a particle size of 1 to 5 microns. 12. Cleaning agent according to claim 8, characterized in that the thixotropic thickener comprises a long-chain fatty acid with 16 to 20 carbon atoms in an amount of 0.03 to 0.20%. 13. Cleaning agent according to claim 8, characterized in that the thixotropic thickener comprises a salt of a polyvalent metal of a long-chain fatty acid with 16 to 20 carbon atoms in an amount of 0.06 to 0.8%. 14. Cleaning agent according to claim 13, characterized in that the polyvalent metal is one of the metals aluminum, calcium, zinc and magnesium. 15. Cleaning agent according to claim 12, characterized in that it additionally contains a thixotropic clay thickener in an amount of 0.1 to 2.5%. 16. Cleaning agent according to claim 13, characterized in that it additionally contains a thixotropic clay thickener in an amount of 0.1 to 2.5%. 17. Commercial process for cleaning dirty glass and dishes in an automatic dishwasher, characterized in that the soiled dishes and glass in the automatic dishwasher are brought into contact with an aqueous washing bath in which an effective amount of the cleaning agent of claim 2 is dispersed. 18. Commercial process for cleaning soiled glass and dishes in an automatic dishwasher, characterized in that the soiled glass and dishes are brought into contact in an automatic dishwasher with an aqueous washing bath in which an effective amount of the cleaning agent of claim 8 is dispersed. 14