PT100550A - Linear viscoelastic aqueous liquid detergent composition for automatic dishwashers containing a thickener of the cross-linked polyacrylic acid type - Google Patents

Abstract

This invention relates to a detergent composition for automatic dishwashers which is formulated as a linear viscoelastic pseudoplastic aqueous product of the gel type having exceptionally good physical stability when exposed to daylight, with little residue in the bottle, little loss in glasses and better cleaning performance. Linear viscosity and pseudoplastic behaviour are obtained by incorporating at least one thickener of the cross- linked polyacrylic acid type having a high molecular weight. Potassium to sodium ratios by weight of at least 1/1 reduce the quantity of undissolved solid particles to a minimum in order better to contribute to the stability and pourability characteristics of the composition. Control of the incorporated air bubbles has the function of giving the product a bulk density of between 1.35 g/cm3 and 1.40 g/cm3 which approximately corresponds to the density of the liquid phase. The presence of a stearic acid or other fatty acid or salt in the composition further improves its physical stability.

Description

2

Rationale of the Invention

Automatic dishwashing liquid detergent compositions, both aqueous and non-aqueous, have recently been the subject of much attention, and aqueous products have achieved commercial popularity. The acceptance and popularity of liquid formulations as compared to the more conventional spray products comes from the convenience and yield of liquid products. However, even the best of the normally marketed liquid formulations still suffer from two main problems, namely phase instability of the product and residue in the bottle and somehow loss in the dispensing cup of the automatic dishwasher.

As representative of important patents in this technical area, reference is made to U.S. Patent 4,556,504 to Rek; U.S. Patent 4,226,736 to Bush, et al., U.S. Patent 4,431,559 to Ulrich; U.S. Patent 4,147,650 to Sabatelli; U.S. Patent 4,079,015 to Paucot; U.S. Patent 4,116,849 to Leikhem; U.S. Patent 4,521,332 to Milora; U.S. Patent 4,597,889 to Jones; U.S. Patent 4,512,908 to Heile; U.S. Patent 4,753,748 to Laitem; U.S. Patent 3,579,455 to Sabatelli; U.S. Patent 3,684,722 to Hynam. Other patents relating to thick detergent compositions include U.S. Patent 3,985,668; GB Patent 2,116,199A and GB 240,450A; U.S. Patent 4,511,487; U.S. Patent 4,752,409 (Drapier, et al.); U.S. Patent 4,801,395 (Drapier, et al.). Commonly assigned patents, also pending, include, for example, Serial No. 204,476, filed June 9, 1988; Series No. 924,385, filed October 29, 1986; Series No. 323,138, filed March 13, 1989; Series No. 3

087,836, filed August 21, 1987; Series No. 328,716, filed March 27, 1989; Series No. 323,137, filed March 13, 1989; Serial No. 323,134, filed March 13, 1989. The present invention provides a solution to the above problems.

Brief Description of Drawings

Figures 1-13 are rheograms indicating elastic moduli G 'and viscous modulus G "as a function of applied stress, for the compositions of Example 1, Formulations A, C, D, G, J, Η, I and K, Example 2, A and B, Example 3, L and M and Comparative Example 1, respectively.

Summary of the Invention

According to the present invention, there is provided a new automatic liquid dishwashing liquid detergent composition. The composition is characterized by its linear viscoelastic behavior, substantially indefinite stability against phase separation or settling of dissolved or suspended particles, low levels of residue in the bottle, relatively high density and substantial absence of unbound or free water. This unique combination of properties is achieved due to the incorporation in the aqueous mixture of dishwashing detergent surfactant, alkali metal salt or detergent builder salts and chlorine bleaching compound, a sodium polyacrylate polymer, which does not form crosslinking agent having a molecular weight of 1,000 to 20,000 and a small but effective amount of high molecular weight crosslinking polyacrylic acid thickening agent, a physical stabilizing amount of a long chain fatty acid or its salt, and a source of potassium ions to provide a potassium / sodium weight ratio in the range of 1: 1 to 45: 1 such that practically all builder salts for detergents and other normally solid detergent additives present in the composition are dissolved in the aqueous phase. The compositions further comprise a density of at least 1.28 g / cm, so that the density of the polymer phase and the density of the (continuous) aqueous phase are approximately equal.

Detailed Description and Preferred Embodiments of the Invention

The compositions of this invention are aqueous liquids containing various active cleansing ingredients, detergent adjuvants, builders and thickeners and stabilizing components, although some ingredients may serve more than one of these functions.

Advantageous features of the compositions of this invention, including physical stability, small residue in the bottle, high cleaning yield, e.g. small stain and film formation, dirt debris removal, etc., and superior aesthetic characteristics, are believed to be attributed to various interconnected factors, such as low solids content, i.e. undissolved particulate content, product density and linear viscoelastic rheology. These factors are, in turn, dependent on several critical composition components of the formulations, namely, (1) inclusion of a thickening effective amount of polymeric thickening agent having a high

(2) inclusion of a physical stabilizing amount of a long chain fatty acid or its salt, (3) ratio by weight of ion (K / Na) in the range of from 1: 1 to 45: 1, especially from 1: 1 to 3: 1, (4) a density of the product of at least 1.28%. g / cm, so that the density and density of the liquid phase is almost the same; and a low molecular weight crosslinking polymer chelating agent, namely sodium polyacrylate, which functions as a chelating agent for heavy and transition metal ions. The decomposition of the sodium hypochlorite bleaching agent is accelerated by heavy and transition metal ions which are present in the composition as trace impurities found in the alkali metal tripolyphosphate, namely potassium triphosphate, which is added to the composition as the structuring salt for detergents. The low molecular weight sodium polyacrylate polymer having a molecular weight of 1,000 to 20,000 acts as a chelating agent for heavy and transition metal ions, thereby chemically linking these heavy and transition metal ions such as iron, copper and cobalt. This chelation avoids heavy metals and transition metals from causing degradation of the sodium hypochlorite bleaching agent in the composition.

Polymeric thickening agents contribute to the linear viscoelastic rheology of the compositions of the invention. As used herein, the term " linear viscoelastic " or " linear viscoelasticity " means that the elastic modules (accumulation) (G ') and the viscous (loss) modules (G' ') are both substantially voltage independent at least in an applied voltage range of 0-50%, preferably in an applied voltage range from 0 to 80%. More specifically, a composition is considered to be 6

as linear viscoelastic for the purposes of this invention if, in a 0-50% strain range, the elastic modules G 'have a minimum value of 10 N / m (100 dynes / cm), preferably at least 25 N / m (250 dynes / cm) and has a variation of less than 250 dynes / cm (500 dynes / cm), preferably less than 30 N / m (300-2 dynes / cm, most preferably less than 10 N / m (100. 2 dynes / cm) Preferably, the minimum value of G 'and maximum variation of G' is in the voltage range of 0 to 80% Typically, the variation in loss modules G " will be lower Another feature of the preferred linear viscoelastic compositions is that the ratio of G '/ G' (tg 5) is less than 1, preferably less than 0.8, although greater than 0.05, preferably greater than 0.2, at least in a range of 0 to 50%, and preferably in a range of 0 to 80%. In this connection it should be noted that% of stress is shear stress x 100.

For better explanation, the elastic modulus G 'is a measure of accumulated energy and recovered when a voltage is applied to the composition, while the viscous (loss) modulus G "is a measure of the amount of energy dissipated in the form of heat when voltage is applied. Therefore, a value of tg 5, 0.05 < tg 5 &lt; 1 preferably 0.2 &lt; tg &lt; 0.8 means that the compositions will retain sufficient energy when a force or tension is applied to at least the extent expected to be encountered for products of this type, for example when spilled or agitated in the bottle, or stored in the dispenser cup of detergent. automatic dishwasher for 7 7

return to their previous state when the force or voltage is interrupted. Compositions with tg S values in these ranges will therefore have a high cohesive characteristic, namely, when a cut or strain is applied to a portion of the composition to cause its flowability, the surrounding portions will become fluid. As a result of this cohesion of the linear viscoelastic compositions in question, the compositions will flow uniformly and homogeneously from a bottle when it is inclined, thus contributing to the physical (phase) stability of the formulation and small residue in the bottle (poor product loss in the bottle ) which characterizes the compositions of the invention. The linear viscoelastic feature also contributes to improved physical stability against phase separation of any undissolved particles in suspension, providing a resistance to particle movement due to the tension exerted by a particle in the surrounding fluid medium.

Also contributing to the physical stability and small residue in the bottle of the compositions of the invention are the high potassium to sodium ion ratios in the range of 1: 1 to 45: 1, preferably 1: 1 to 4: 1, most preferably 1.05: 1 to 3: 1, for example 1.1: 1, 1.2: 1, 1.5: 1, 2: 1 or 2.5: 1. In these relationships, the solubility of the solid salt components, such as builder salts for detergents, bleaching agent, alkali metal silicates and the like, is substantially increased since the presence of the potassium (K +) ions requires less water of hydration than the ions of sodium (Na), so that more water is available to dissolve these saline compounds. Accordingly, all or nearly all of the normally solid components are present dissolved in the aqueous phase. Since there is none or only a very small percentage, namely, less than 5%, preferably less than 3% by weight, of suspended solids present in the formulation, there is no δ

any tendency or only a reduced tendency exists for undissolved particles to form sediments of the compositions, for example by causing hard particle formation which could result in high residues in the bottle (i.e. loss of product). Furthermore, any undissolved solids tend to be present in extremely small particle size, usually colloidal or sub-colloidal, such as 1 micron or less, thereby further reducing the tendency for sedimentation of the undissolved particles.

Another attribute of the compositions of this invention which contributes to the overall stability of the product and small residue in the bottle is the high water absorption capacity of the crosslinked polyacrylic acid type thickening agent. As a result of this high water absorption capacity, the entire aqueous carrier component is kept intimately connected to the polymer matrix. Therefore, there is none or virtually no free water present in the compositions of the invention. This absence of free water (as well as the cohesive capacity of the composition) is manifested by the observation that, when the composition is poured from a bottle to a piece of water absorbent filter paper, no water is virtually absorbed by the filter paper and furthermore the mass of the linear viscoelastic material poured into the filter paper will retain its shape and structure until it is again subjected to a force or tension. As a result of the absence of unbound or free water, there is virtually no phase separation between the aqueous phase and the polymer matrix or dissolved solids. This characteristic is manifested by the fact that when the compositions in question are subjected to centrifugation, for example at 1000 rpm for 30 minutes, there is no phase separation and the composition remains homogeneous. 9

However, it has also been found that the linear viscosity and K / Na ratios in the above-mentioned range do not in themselves ensure long-lasting physical stability (as determined by phase separation). To maximize the physical (phase) stability, the density of the composition should be controlled such that the density of the liquid phase is approximately equal to the density of the complete composition, including the polymeric thickening agent. This control and equalization of densities are achieved according to the invention by providing the composition with a density of hair 3. 3 to 1.28 g / cm2, preferably at least 1.32 g / cm2, to 1.42 g / cm2, preferably 1.40 g / cm2. Moreover, in order to obtain these relatively high mass densities, it is important. reducing the amount of air incorporated in the composition (a density of 1.42 g / cm2 is essentially equivalent to an air content of zero).

It has previously been found in connection with other types of aqueous liquid detergent compositions thickened for automatic dishwashers that the incorporation of finely divided air bubbles in amounts of up to 8 to 10% by volume can function effectively to stabilize the composition against phase separation but that in order to avoid agglomeration or leakage of the air bubbles it is important to incorporate certain surface active ingredients, especially higher fatty acids and their salts, namely stearic acid, behenic acid, palmitic acid, sodium stearate, aluminum stearate, and the like. These surfactants have apparently had the function of forming an interfacial film on the surface of the bubbles, while also forming hydrogen bonds or contributing to electrostatic attraction with the particles in suspension, so that the air bubbles and the attracted particles form agglomerates out of 10

density approximately equal to the density of the continuous liquid phase.

Therefore, in a preferred embodiment of the present invention, stabilization of air bubbles which may be incorporated into the compositions during normal processing, in particular during the various mixing steps, is avoided by the subsequent addition of the surfactants, including fatty acid stabilizer or fatty acid salt, to the remainder of the composition under low shear conditions using blending devices designed to minimize cavitation and vortex formation.

As will be described in more detail below, the surface active ingredients present in the composition will include the main detergent surfactant, and will also preferably include antifoaming agent and higher fatty acid or its salt as a physical stabilizer. Crosslinked polyacrylic acid type thickening agents are exemplary of the products sold by BFGoodrich, under the tradename &quot; Carbopol &quot;, namely &quot; Carbopol 941 &quot;, which is the most insensitive to ions of this class of polymers, and &quot; Carbopol 940 &quot; and &quot; Carbopol 934 &quot;. Carbopol &quot; resins, also known as &quot; Carbomer &quot;, are hydrophilic, high molecular weight crosslinked acrylic acid polymers having an average equivalent weight of 76, and the general structure shown by the following formula: n H 1 n HW 1 c. A HO < J η &quot; Carbopol 941 &quot; has a molecular weight of 1,250,000, &quot; Carbopol 940 &quot; has a molecular weight of 4,000,000 and &quot; Carbopol 934 &quot; has a molecular weight of 3,000,000. The resins of &quot; Carbopol &quot; form crosslinking with polyalkenyl polyether, for example, 1% of a sucralose polyallyl ether having a mean of 5.8 allyl groups for each sucrose molecule. There is more detailed information about the resins &quot; Carbopol &quot; provided by B.F. Goodrich, see, for example, the catalog of B.F. Goodrich &quot; GC-67 &quot;, Carbopol Water Soluble Resins.

While the most favorable results were obtained with polyacrylic resin &quot; Carbopol 941 &quot;, other slightly cross-linked polyacrylic acid type thickening agents may also be used in the compositions of this invention. As used herein, the term &quot; polyacrylic acid type &quot; refers to water soluble homopolymers of acrylic acid or methacrylic acid, or the water-soluble or water-dispersible salts, esters or amides thereof, or water-soluble copolymers of these acids, their salts, esters or amides, with one another or with one or more other ethylenically unsaturated monomers such as, for example, styrene, maleic acid, maleic anhydride, 2-hydroxyethyl acrylate, acrylonitrile, vinyl acetate, ethylene, propylene and the like.

These homopolymers or copolymers are characterized by their high molecular weight in the range of 500,000 to 10,000,000, preferably 500,000 to 5,000,000, especially 1,000,000 to 12,000,000, and their solubility in water, generally at less in an extent up to 5% by weight or more in water at 25 ° C.

These thickening agents are used in their slightly cross-linked form, wherein cross-linking can be obtained by means known in the art of polymeric techniques, in particular by irradiation, or preferably by incorporation into the monomer mixture, to be polymerized , of known cross-linking chemical monomeric agents, typically polyunsaturated (eg, diethylenically unsaturated) monomers such as, for example, divinylbenzene, diethylene glycol divinyl ether, N ', N'-methylenebisacrylamide , polyalkenyl polyethers (such as those described above), and the like. Typically, amounts of cross-linking agent to be incorporated into the final polymer may range from 0.01 to 1.5%, preferably from 0.05 to 1.2%, and especially preferably from 0.1 to 0, 9% by weight of crosslinking agent relative to the weight of the total polymer. In general, those skilled in the art will recognize that the degrees of cross-linking should be sufficient to provide some winding to the otherwise generally linear polymeric compound, the crosslinking polymer still remaining at least water dispersible and highly swellable in water in an aqueous ionic medium. It is also evident that the water swellability of the polymer which provides the desired thickening and viscous properties depends on one or two mechanisms, namely conversion of the acid group containing polymers to the corresponding salts, for example sodium, generating negative charges along the spine dorsal portion of the polymer, thereby causing the expansion of the coiled molecules and the thickening of the aqueous solution; or by the formation of hydrogen bonds, for example, between the carboxyl groups of the polymer and the hydroxyl donor. The first mechanism is especially important in the present invention and, therefore, agents 13

polyacrylic acid type thickeners will contain free carboxylic acid (COOH) groups along the backbone of the polymer. It will also be apparent that the degree of crosslinking should not be so high that the crosslinking polymer is completely insoluble or non-dispersible in water or that inhibits or prevents the unwinding of the polymer molecules in the presence of the aqueous ionic system. The amount of the high molecular weight crosslinking polyacrylic acid or other high molecular weight hydrophilic crosslinking polyacrylic acid thickener intended to provide the desired rheological property of linear viscoelasticity will be generally in the range of 0.1 to 2%, preferably 0.2 to 1.4%, by weight, based on the weight of the composition, although the amount depends on the specific crosslinking agent, ionic strength of the composition, donors hydroxyl and the like.

The compositions of this invention should include a quantity of potassium ions and sufficient sodium ions to provide a K / Na weight ratio of at least 1: 1, preferably 1: 1 to 45: 1, especially 1: 1 to 3: 1, more preferably from 1.05: 1 to 3: 1, in particular 1.5: 1, or 2: 1. When the K / Na ratio is less than 1, there is insufficient solubility of the normally solid ingredients, whereas when the K / Na ratio is greater than 45, especially when it is greater than 3, the product becomes too liquid and phase separation occurs. When K / Na ratios become much higher than 45, as in a complete or almost complete potassium formulation, the polymeric thickener loses its absorption capacity and begins to salinize from the aqueous phase. 14

Potassium and sodium ions may be present in the compositions, such as the alkali metal cation of the detergent builder salts or salts, or alkali metal silicate or alkali metal hydroxide components of the compositions. The alkali metal cation may also be present in the compositions as a component of ionic detergent, bleaching agent or other ionizable salt compound additive, for example, alkali metal carbonate. In determining the weight ratios of K / Na, all these sources must be taken into account.

Specific examples of builder salts for detergents include polyphosphates, such as alkali metal pyrophosphate, alkali metal tripolyphosphate, alkali metal metaphosphate, and the like, for example sodium or potassium (hydrated or anhydrous) tripolyphosphate, tetrasodium or tetrapotassium pyrophosphate, hexa sodium or potassium metaphosphate, trisodium or tripotassium orthophosphate and the like, sodium or potassium carbonate, sodium or potassium citrate, potassium sodium nitrilotriacetate, and the like. Phosphate builders, if not avoided due to local regulations, are preferred, and mixtures of tetrapotassium pyrophosphate (TKPF) and sodium tripolyphosphate (NaTPF) (especially hexahydrate) are especially preferred. Typical NaTPF ratios for TKPF are from 2: 1 to 1: 8, especially 1: 1.1 to 1: 6. The total amount of builder salts for detergents is preferably 5 to 35% by weight, more preferably 15 to 35%, especially 18 to 30% by weight, of the composition.

The linear viscoelastic compositions of this invention may contain, and preferably contain, a small but stabilizing effective amount of a long chain fatty acid or its monovalent or polyvalent salt. While the manner in which the fatty acid or salt contributes to the rheology and stability of the composition has not been fully elucidated, it is hypothesized that it may function as a hydrogen bonding agent or crosslinking agent for the polymeric thickener -rich.

Preferred long chain fatty acids are the higher aliphatic fatty acids having 8 to 22 carbon atoms, more preferably 10 to 20 carbon atoms, and most preferably 12 to 18 carbon atoms, inclusive of the carbon atom of the group carboxyl group of the fatty acid. The aliphatic radical may be saturated or unsaturated and may be straight or branched. The saturated straight chain fatty acids are preferred. Mixtures of fatty acids, such as those derived from natural sources, such as tallow fatty acid, coconut fatty acid, soy fatty acid, mixtures of such acids etc. may be used. Stearic acid and mixed fatty acids, for example, stearic acid / palmitic acid, are preferred.

When the free acid form of the fatty acid is used directly, it will generally be associated with the potassium and sodium ions in the aqueous phase to form the corresponding alkali metal fatty acid soap. However, the fatty acid salts can be directly added to the composition in the form of the sodium salt or potassium salt, or as a polyvalent metal salt, although the alkali metal salts of the fatty acids are the preferred fatty acid salts.

Preferred polyvalent metals are the bi- and trivalent metals of Groups IIA, IIB and IIIB, namely magnesium, calcium, aluminum and zinc, although other polyvalent metals may also be used, including those of Groups IIIA, IVA, VA, IB, IVB , VB, VIB, VIIB and VIII of the Periodic Table of the 16

Elements. Specific examples of these other polyvalent metals include Ti, Zr, V, Nb, Mn, Fe, Co, Ni, Cd, Sn, Sb, Bi, etc. Generally, metals may be present in the bivalent to pentavalent state. Preferably, the metal salts are used in their higher oxidation states. Of course, for use in automatic dishwashers as well as in any other applications where the composition of the invention is or may come in contact with articles used for the handling, storage or serving of food, or otherwise contact, or be consumed by humans or animals, the metal salt must be selected taking into account the toxicity of the metal. To this end, the magnesium and calcium and alkali metal salts are especially preferred as generally safe food additives. The amount of the fatty acid stabilizer or fatty acid salt required to achieve the desired increase in physical stability will depend on factors such as the nature of the fatty acid or salt thereof, the nature and amount of the thickening agent, detergent active compound, salts inorganic, other ingredients, as well as conditions of anticipated storage and shipment.

Generally, however, amounts of fatty acid stabilizing agents or fatty acid salt in the range of 0.02 to 2%, preferably 0.04 to 1%, more preferably of 0.06 to 0.8%, very preferably from 0.08 to 0.4%, provide long-term stability and absence of phase separation at rest or during transport at both high and low temperatures, as is required for a commercially acceptable product.

Depending on the amounts, proportions and types of physical stabilizers of fatty acid and thickening agents of 17

polyacrylic acid type, the addition of the fatty acid or salt not only increases the physical stability, but also provides a simultaneous increase in apparent viscosity. Amounts of fatty acid or salt for polymeric thickening agent in the range of 0.08-0.4% by weight of fatty acid salt and 0.4-1.5% by weight of polymeric thickening agent are usually sufficient to provide these simultaneous benefits, and therefore the use of these ingredients in these amounts is more preferred.

In order to achieve the desired benefit of the fatty acid stabilizer or fatty acid salt without stabilizing excess air bubbles and consequently excessive reduction of the density of the product, the fatty acid or salt should be added to the formulation thereafter, preferably together with the other surface-active ingredients, including detergent active compound and antifoaming agent, when present. These surfactant ingredients are preferably added in the form of an emulsion in water, wherein the oily or oily emulsified materials are thin and homogeneously dispersed throughout the aqueous phase. To achieve the desired fine emulsification of the fatty acid or fatty acid salt and other surface active ingredients, it is generally necessary to heat the emulsion (or preheat the water) to an elevated temperature close to the melting temperature of the fatty acid or its salt . For example, for stearic acid having a melting point of 68-69Â ° C, a temperature in the range of 50Â ° C to 70Â ° C will be used. For lauric acid (mp = 47 ° C), a high temperature of 35 ° to 50 ° C may be used. Apparently, at these elevated temperatures, the fatty acid or salt and other surface active ingredients may be more easily and evenly dispersed (emulsified) in the form of fine droplets throughout the composition. 18 18

In contrast, as will be seen in the examples which will follow, if the fatty acid is simply added subsequently at room temperature, the composition is not linear viscoelastic as defined above and the stability of the composition is clearly lower. Foam inhibition is important to increase the efficiency of the washer and to minimize the destabilizing effects that could occur as a result of the presence of too much foam inside the machine during use. The foam may be reduced by appropriate selection of the type and / or amount of detergent active material, the main foam generating component. The degree of foam is also somewhat dependent on the hardness of the washing water in the machine, and a suitable adjustment of the proportions of the structuring salts, namely NaTPF, which has a water softening effect, can contribute to provide a degree of foam inhibition. However, it is generally preferred to include a stable foam inhibitor or suppressant in the presence of the bleach based on chlorine. Particularly effective are the alkyl esters of phosphoric acid of formula 0

II

HO-P-R

OR and in particular the alkyl acid phosphate esters of the formula

0 • I

HO-P-OR

OR 19

In the foregoing formulas, one or both R groups in each ester type may independently represent a C 12 -C 20 alkyl group. The ethoxylated derivatives of each ester type may also be used, for example, condensation products of one mole of ester with 1 to 10 mol, preferably 2 to 6 mol, more preferably 3 or 4 mol of ethylene oxide. Some examples of the foregoing are commercially available, namely &quot; SAP &quot; of Hooker and &quot; LPKN-158 &quot; of Knapsack. Mixtures of the two types, or any other stable types in the presence of chlorine bleaching agents, or mixtures of mono- and di-esters of the same type may be used. Especially preferred is a mixture of mono- and di-C 16 -C 11 alkyl acid phosphate esters such as monostearyl / di-stearyl acid phosphates 1.2 / 1, and their condensates of 3 to 4 moles of oxide of ethylene. When used, proportions of 0.05 to 1.5% by weight, preferably 0.1 to 0.5% by weight, of suds suppressor in the composition, typically varying the ratio by weight of component active detergent (d) for foam suppressant (e) from 10: 1 to 1: 1, and preferably 5: 1 to 1: 1. Other suppressors which may be used include, for example, the known silicones, such as those sold by Dow Chemicals. Furthermore, it is an advantageous aspect of this invention that many of the stabilizing salts, namely the stearate salts, for example, aluminum stearate, when included, are also effective as foam suppressants.

Although any chlorine bleaching compound, namely dichloro-isocyanurate, dichloro-dimethylhydantoin, or chlorinated TSF, may be used in the compositions of this invention, alkali metal or alkaline earth metal hypochlorite, for example, potassium, lithium , magnesium and especially sodium. The composition should contain sufficient amount of chlorine bleaching compound to provide 0.2 to 4.0%, in 20

weight ratio of available chlorine as determined, for example, by acidifying 100 parts of the composition with excess hydrochloric acid. A solution containing 0.2 to 4.0% by weight of sodium hypochlorite contains or provides almost the same percentage of available chlorine. Particularly preferred is a proportion of 0.8 to 1.6% by weight available chlorine. For example, sodium hypochlorite (NaOCl) solution of 11 to 13% available chlorine may be used in amounts of 3 to 20%, preferably 7 to 12%. The detergent active material useful for this purpose should be stable in the presence of bleach based on chlorine, especially bleach based on hypochlorite and to that end, those of the surfactant types dispersible in organic anionic water, amine, phosphine oxide, sulfoxide or betaine, the most preferred being the anionic ones mentioned first. Particularly preferred surfactants are mono- and di- (C0-C ..) -alkyl-diphenyl-oxide-mono- and / or disulphates of branched or

linearly commercially available, for example as &quot; DOWFAX $ (trade mark) 3B-2 &quot; and &quot; DOWFAX 2A-1 &quot;. In addition, the surfactant should be compatible with the other ingredients of the composition. Other suitable organic anionic non-saponified surfactants include alkyl sulphates, alkyl sulphonates, primary alkyl aryl sulphonates and sec.alkyl sulphates. Examples include sodium C alquil alquil alquilalkylsulfates such as -LUL, sodium dodecylsulfate and sodium alcoholsulfate and tallow; sodium alkane sulfonates such as sodium hexadecyl-1-sulphonate and sodium C 10 -C 10 alkyl benzene sulfonates such as

As well as sodium dodecyl benzene sulfonates. The corresponding potassium salts can also be used.

I 21

Like other suitable surfactants or detergents, the amine oxide surfactants are typically of the structure wherein each R represents a lower alkyl group, for example methyl, and R represents a lower alkyl group long group having 8 to 22 carbon atoms, for example a lauryl, myristyl, palmityl or cetyl group. In place of an amine oxide, a corresponding surfactant of phosphine oxide 11 PO or RR sulphoxide may be used. Betaine surfactants are typically of the structure NR''COO-, where each R represents a lower alkylene group having 1 to 5 carbon atoms. Specific examples of such surfactants include lauryl dimethyl amine oxide, myristyl dimethyl amine oxide, the corresponding phosphine oxides and sulphoxides, and the corresponding betaines, including dodecyl dimethyl ammonium acetate, tetradecyldiethyl pentanoate, ammonium hexadecyl dimethyl ammonium hexanoate and the like. For reasons of biodegradability, the alkyl groups in these surfactants should be linear, such compounds being preferred.

Surfactants of the foregoing type, all well known in the art, are described, for example, in U.S. Patents 3,985,668 and 4,271,030. If no chlorine bleach compound is used, then any of the well-known non-ionic surfactants of poor foaming, such as alkoxylated fatty alcohols, may also be used, for example, mixed ethylene oxide-propylene oxide condensates of alcohols C--C gord fatty acids. The water dispersible organic detergent (surfactant) active material stable in the presence of the chlorine bleaching agent will normally be present in the composition in minor amounts, generally 1% by weight of the composition, although smaller or larger amounts may be used , 22

in particular up to 5%, for example 0 to 5%, preferably 0.3 or 0.4 to 2%, by weight of the composition. Generally alkali metal silicate (for example potassium or sodium), which provides alkalinity and protection of hard surfaces, such as gloss and fine porcelain pattern, is used in an amount ranging from 5 to 20% by weight, preferably 5 to 15% by weight, more preferably 8 to 12% by weight in the composition. Sodium or potassium silicate is generally added in the form of an aqueous solution, preferably having a Na2 O: SiC> 2 or K20: SiC> 2 ratio of 1: 1.3 to 1: 2.8, most preferably 1: 2.0 to 1: 2.6. It should now be noted that many of the other components of this composition, in particular alkali metal hydroxide and bleaching agent, are also frequently added in the form of a preliminarily prepared aqueous solution or dispersion.

In addition to detergent active surfactant, foam inhibitor, alkali metal silicate based corrosion inhibitor, and detergent builder salts, which all contribute to cleaning performance, it is also known that the effectiveness of the machine liquid detergent compositions Automatic dishwasher is related to alkalinity, and particularly with the moderation of high levels of alkalinity. Accordingly, the compositions of this invention will have pH values of at least 9.5, preferably at least 11 at values as high as 14, generally up to 13 or more, and, when added to the aqueous wash bath at a concentration level typical of 10 grams per liter, will provide a pH in the wash bath of at least 9, preferably at least 10, in particular 10.5, 11, 11.5 or 12 or more. 23 23

The alkalinity will be in part achieved by the alkali metal ions provided by the alkali metal builder salts, for detergents, for example sodium tripolyphosphate, tetrapotassium pyrophosphate and alkali metal silicate; however, it is usually necessary to include alkali metal hydroxide, for example NaOH or KOH, to obtain the desired high alkalinity. Amounts of alkali metal hydroxide in the range (on an active basis) of 0.5 to 8%, preferably 1 to 6%, more preferably 1.2 to 4% by weight of the composition, will be sufficient to obtain of the desired pH level and / or for adjusting the weight ratio of K / Na.

Other alkali metal salts, in particular alkali metal carbonates, may also be present in the compositions in minor amounts, for example 0 to 4%, preferably 0 to 2%, by weight of the composition.

The linear viscoelastic compositions of the present invention will contain 0.1 to 10.0% by weight, more preferably 0.2 to 4.0% by weight of a polymeric chelating agent, which is capable of chelating heavy metal ions and such as copper, iron and cobalt in the composition. The alkali metal polyphosphates used as builder salts for detergents in the composition contain trace impurities of these heavy and transition metal ions. The presence in the composition of the heavy and transition metal ions accelerates the decomposition of the sodium hypochlorite bleaching agent in the composition, thereby deleteriously affecting the stability of the composition. A suitable polymer chelating agent is a low molecular weight crosslinking sodium acrylate polymer having a molecular weight of from 1,000 to 20,000, for example &quot; Good-Rite K-7058N &quot; sold by B.F. Goodrich - 24 - - 24 -

Chemical Company, having a molecular weight, as determined by Gel Permeation Chromatography, of 5,800.

Other conventional ingredients may be included in these compositions in small amounts, generally less than 3% by weight, namely perfume, hydrotropic agents such as benzene, toluene, xylene and sodium cumene sulfonates, preservatives, dyes and pigments and the like, all of which evidently stable in the presence of chlorine bleaching compound and high alkalinity. Particularly preferred as dyes are chlorinated phthalocyanines and aluminosilicate polysulfides, which respectively provide pleasant shades of green and blue. Tic &gt; 2 can be used to bleach or neutralize discolorations.

Although, for the reasons given above, an excess of air bubbles in the compositions of the invention, depending on the amounts of dissolved solids and densities of the liquid phase, the incorporation of small amounts of finely divided air bubbles, generally up to 10%, is not desirable, by volume, preferably up to 2% by volume, may occur to adjust the bulk density to a density close to the liquid phase. The incorporated air bubbles should be finely divided, such as up to 100 microns in diameter, preferably 20 to 40 microns in diameter, to ensure maximum stability. Although air is the preferred gaseous medium for adjusting densities to improve the physical stability of the composition, other inert gases, such as nitrogen, carbon dioxide, helium, oxygen, etc. may also be used. The amount of water contained in such compositions should obviously not be so high that it produces unduly low viscosity and fluidity, or so low that it produces unduly high viscosity and poor fluidity, both of which are reduced or destroyed by viscoelastic properties These amounts are readily determined by routine experimentation in each specific case, generally ranging from 30 to 75% by weight, preferably 35 to 65% by weight. The water should preferably be deionized or softened. The manner of formulating the compositions of the invention is also important. As noted above, the mixing order of the ingredients as well as the manner in which the blending is performed will generally have a significant effect on the properties of the composition, and in particular on product density (by incorporation and stabilization of more or less air) and physical stability (eg phase separation). Thus, according to the preferred practice of this invention, the compositions are prepared by first forming a dispersion of the polyacrylic acid thickener in water under moderate to high shear conditions, neutralizing the dissolved polymer to cause gelation, the detergent builder salts, alkali metal silicates, chlorine bleaching compound, the polymer chelating agent, and the remaining detergent additives, including any previously non-alkali metal hydroxide, are discussed below. used, if any, in addition to the surfactants. All supplemental ingredients may be added simultaneously or sequentially. Preferably, the ingredients are added sequentially, although it is not necessary to complete the addition of one ingredient before starting the addition of the next ingredient. In addition, one or more of these ingredients may be divided into portions and added several times. These mixing steps should also be performed under moderate to high shear conditions to provide a

complete and uniform mixing. These mixing steps may be performed at room temperature, although neutralization with polymeric thickener (gelling) is usually exothermic. The composition may be allowed to age, if necessary, to cause dissolved or dispersed air to dissipate from the composition.

The remaining surfactants, including the antifoam agent, organic detergent compound and fatty acid stabilizer or fatty acid salt are subsequently added to the pre-formed mixture as an aqueous emulsion (using 10% , preferably from 2 to 4% of the total water added to the composition in addition to the water added as vehicle for other ingredients or water of hydration), which is preheated to a temperature in the range of Tf + 5 to Tf-20, preferably Tf to Tf-10, where Tf is the melting point temperature of the fatty acid or the fatty acid salt. For the preferred stearic acid stabilizer, the heating temperature is in the range of 50 ° C to 70 ° C. However, if care is taken to avoid excessive entrapping of air bubbles during the gelling step or during mixing of the structural salts for detergents and other additives, for example by operating under vacuum, or by using conditions of low cut, or special mixing apparatus, etc., the order of addition of the surfactants should be less important.

According to a particularly preferred embodiment of the invention, the automatic dishwasher-type linear viscoelastic automatic dishwashing detergent composition of this invention comprises, on a weight basis: (a) 10 to 35%, preferably 15 to 30% %, from builder for detergents based on alkali metal polyphosphate; (b) 5 to 15%, preferably 8 to 12%, of alkali metal silicate; (c) 1 to 6%, preferably 1.2 to 4%, of alkali metal hydroxide; (d) from 0 to 5%, preferably from 0.1 to 3%, of poor detergent organic detergent active material, water dispersible, stable in the presence of the chlorine bleaching agent, preferably anionic detergent not saponified; (e) 0 to 1.5%, preferably 0.05 to 0.5%, of stable suds suppressor in the presence of chlorine bleaching agent; (f) chlorine bleaching compound in an amount sufficient to provide 0.2 to 4%, preferably 0.8 to 1.6% available chlorine; (g) at least one high molecular weight hydrophilic crosslinking polyacrylic acid thickening agent in an amount sufficient to provide a linear viscoelasticity to the formulation, preferably 0.1 to 2.0%, more preferably 0.1 to 1.5%; (H) a long chain fatty acid or a metal salt of a long chain fatty acid in an amount effective to increase the physical stability of the compositions, preferably from 0.08 to 0.4%, more preferably from 0, 1 to 0.3%; (i) 0.1 to 10.0% of a polymeric chelating agent having a molecular weight of from about 1,000 to about 20,000; and

(j) water to be made, preferably from 30 to 75%, more preferably from 35 to 65%; and wherein in (a) the alkali metal polyphosphate comprises a mixture of 5 to 30%, preferably 12 to 22%, of tetrapotassium pyrophosphate, and 0 to 20%, preferably 3 to 18% of tripolyphosphate of sodium, and wherein, throughout the composition, the weight ratio of potassium ions to sodium ions is from 1.05 / 1 to 3/1, preferably from 1.1 / 1 to 2.5 / 1, the compositions having such an amount of air such that the density of the composition is 1.32 to 1.42 g / cm 3, preferably 3 1.35 to 1.40 g / cm 2.

The compositions will be provided to the consumer in suitable dispensing containers, preferably formed of molded plastic, in particular polyolefin plastic, and more preferably polyethylene, in which the compositions of the invention appear to have particularly favorable sliding characteristics. In addition to their linear viscoelastic nature, the compositions of this invention may also be characterized as pseudoplastic (non-thixotropic) gels, which are typically close to the boundary between solid viscoelastic gel and liquid, depending, for example, on the amount of polymeric thickener. The compositions of the invention can be easily poured from their containers without any agitation or compression, although the containers of compression are often convenient and accepted by the consumer for gel-like products.

The liquid aqueous linear dishwashing machine compositions of this invention are easy to use, in the known manner for washing dishes, other kitchenware and the like, in an automatic dishwasher equipped with a suitable detergent dispensing container in a bath of aqueous washing containing an effective amount of the composition,

usually sufficient to fill or partially fill the dispenser cup of the specific machine to be used. The invention also provides a method for dishwashing in an automatic dishwashing machine with an aqueous washing bath containing an effective amount of the liquid linear viscoelastic automatic dishwashing detergent composition as previously described. The composition can be easily poured from the polyethylene container with little or no tightening or shaking into the dispensing cup of the automatic dishwasher and will be sufficiently viscous and cohesive to remain secured within the dispensing cup until it is again cutting forces, such as those caused by the dishwasher's water jet. The invention may be practiced in various ways and a number of specific embodiments will be described to illustrate the invention in connection with the accompanying examples.

All amounts and proportions referred to herein are based on the weight of the composition, unless otherwise indicated.

I

Example 1 The following formulations A-K are prepared as described below: 1 Ingredient / 1 formulation The perf. The perf. The perf. The perf. The perf. The perf. The perf. The perf. The perf. The perf. &quot; Carbopol 941 &quot; 0.9 0.9 0.9 0.9 1 ... 0.9 0.9 ... 1.5 0.91 NaOH (50%) 2.4 2.4 2.4 2.4 3.5 3.5 2.4 2 , 4 2.4 2.4 KOH (50%) ... - - - - 2.4 ... - TKPF TPF Hexahydrate, Na 13 13 12 7, 5 7.5 7.5 13 7.5 Na silicate (47.5%) (1: 2.3) 21 21 21 21 17 17 21 21 21 21 K Silicate (29.1%) (1: 2, 3) &quot; ** ** 34 LPKN (5%) 3.2 3.2 3.2 3.2 - 3.2 3.2 3.2 3.2 3.2 DOWFAX 3B2 &quot; 1 1 1 1 1 1 1 1 1 1 1 Fatty acid = 0.1 0.1 0.1 0.1 ... ... 0.1 0.1 1 0.1 0.1 Bleaching agent (13 , 0% Cl) 7.5 7.5 7.5 7.5 9.1 9.1 7.5 7.5 7.5 7.5 3 Ar (% by volume) &lt; 2.0 &lt; 2.0 &lt; 2.0 &lt; 2.0 &lt; 2.0 &gt; 2.0 &lt; 2.0 &gt; 2.0 &gt; 2.0 &lt; 2.0 &lt; 2.0 Fragrance. .. 0.17 - --- - - - - ... ... K / Na ratio 1.12 1.12 1.16 1.89 1.95 1.95 4.16 45.15 - 1 , 89 ... Density (g / cfO 1.37 1.37 1.35 1.37 1.36 ... 1.37 ... ... 1.37 1.37 Ratio Fig. 1 Fig.2 Fig. 3 Fig.4 Fig.6 Fig.7 Fig.5 Fig.8 Stability results at room temperature 8 weeks (%) 0.0 0.0 0.0 0.0> 10.0> 10.0 0 , 0> 20.0> 5.0 0.0 Stability Results at 38 ° C (100 ° F) 6 weeks (%) 0.0 0.0 0.0 0.0 &gt; 10.0 &gt;; 10.0 0.0 &gt; 20.0 &gt; 5.0 &gt; Carbopol 940 &quot; Emersol 132 &quot; (Mixture of stearic acid and palmitic acid in a ratio of 1: 1)

All formulations are aerated to a certain degree, depending on the cutting conditions used for the preparation; typically the air volume does not exceed 7-8% by volume, the preferred degree of aeration (2%, by volume) resulting in the stated densities; the air bubbles have on average between 20 and 60 micron in diameter. 31

Formulations A, B, C, D, E, G, J and K are prepared by first forming a uniform dispersion of the thickener &quot; Carbopol 941 &quot; or &quot; Carbopol 940 &quot; in 97% of the water (to be made). 0 &quot; Carbopol &quot; is slowly added to the deionized water at room temperature using a mixer equipped with a main blade with agitation set at a medium shear rate as recommended by the manufacturer. The dispersion is then neutralized by the addition, with mixing, of the caustic soda component (50% NaOH or KOH) to form a thick gel-like thickening product. To the resulting gelled dispersion, silicate, tetrapotassium pyrophosphate (TKPF), sodium tripolyphosphate (TP) (TPF, Na) and bleaching agent are sequentially added sequentially in the order indicated, the mixture continuing to medium shear.

Separately, an emulsion of the phosphate antifoam agent (LPKN), a mixture of stearic acid / palmitic acid and detergent (&quot; Dowfax 3B2 &quot;) is prepared by adding these ingredients to the remaining 3% water ( to be added) and the resulting mixture was warmed to a temperature in the range of 50 ° C to 70 ° C. The heated emulsion is then added to the gelled dispersion previously prepared under low shear conditions so that a vortex does not form.

The remaining formulations F, HeI are prepared essentially in the same manner as described above, with the exception of the heated emulsion of LPKN, stearic acid and &quot; Dowfax 3B2 &quot; be directly added to the neutralized dispersion of &quot; Carbopol &quot; before adding the remaining ingredients. In 32 32

As a result, formulations F, H and I have higher levels of air. . . . 3 incorporated and densities of less than 1.30 g / cm.

The rheograms for formulations A, C, D, G and J are shown in figures 1-5, respectively, and the rheograms for the formulations Η, I and K are indicated in figures 6, 7 and 8, respectively.

These rheograms are obtained with Rheometer System Rheometer 4, equipped with a &quot; Fluid Servo &quot; with a torque transducer of 100 grams-centimeter and a geometry of parallel plates of 50 millimeters, having an aperture of 0.8 millimeters between plates. All measurements are made at room temperature (25øC + 1øC) in a humidity chamber after a 5 minute or 10 minute sample retention period at the aperture. Measurements are made by applying a frequency of 10 radians per second.

All formulations of compositions A, B, C, D, G and J, according to the preferred embodiment of the invention, which include &quot; Carbopol 941 &quot; and stearic acid present linear viscoelasticity, as evident from the rheograms of figure 1-5. Formulation E, which includes &quot; Carbopol 941 &quot; but not stearic acid, did not show phase separation at either ambient temperature or 38øC-100øF after 3 weeks, but showed 10% phase separation after 8 weeks at room temperature and after only 6 weeks at 38 ° C - 100 ° F. Formulation K, containing &quot; Carbopol 940 &quot; instead of &quot; Carbopol 941 &quot;, as disclosed in the diagram of Figure 8, shows a substantial linearity in a voltage range of 2% to 50% (G 'at 2.21% G-voltage at 50% voltage &gt; 50 N / m (500 dynes / cm)), although tg δ &gt; 1 at a voltage greater than 50%.

Example 2

This example demonstrates the importance of the order of adding the premixture of the surfactant components to the remaining part of the composition relative to the density and stability of the product.

The following formulations are prepared by methods A and B:

Ingredient Water, deionized &quot; Carbopol 941 &quot; NaOH (50%) Na Silicate (47.5%) TKPF TPF, In the bleaching agent LPKN Stearic acid &quot; Dowfax 3B2 &quot; to be performed 0.5 2.4 21 15 13 (1%) 7.5 0.16 0.1 1 Method A: &quot; Carbopol 941 &quot; is dispersed at a medium shear rate using a master blade blender in deionized water at room temperature. Add NaOH, with blending, to neutralize and gel the Carbopol 941 dispersion. &Quot; Carbopol 941 &quot;. To the thickened mixture the following ingredients are added in sequence while stirring: sodium silicate, TKPF, TPF and bleaching agent. 34

An emulsion is prepared separately by adding &quot; Dowfax 3B2 &quot;, stearic acid and LPKN to water, while mixing at moderate shear rate and heating the mixture to 65 ° C to finely disperse the surface- active substances emulsified in the water phase. This emulsion premix is then slowly added to the &quot; Carbopol &quot; while the blending operation is performed under low shear conditions without vortexing. The results are presented below. Method B;

Method A is repeated except that the heated emulsion premix is added to the neutralized dispersion of &quot; Carbopol 941 &quot; before sodium stearate, TKPF, TPF and bleaching agent. The results are shown below.

Method A Method B 1.38 1.30 0.00% 7.00% Fig.9 Fig.10

Density

Stability (TA-8 weeks)

Régram i

From the graphs of Figures 9 and 10 it is seen that both products are linear viscoelastic, although the elastic and viscous moduli G 'and G "are higher for Method A than for Method B.

It is apparent from the results that the anticipated addition of the surfactants to the &quot; Carbopol &quot; significantly increases the degree of aeration and reduces the bulk density of the final product. Since the density is lower than the density of the continuous liquid phase, the liquid phase undergoes an inverse separation (a clear liquid phase forms at the bottom of the composition). This reverse separation process appears to be kinetically controlled and will occur much more rapidly as the product density becomes lower.

Example 3

This example shows the importance of the temperature at which the pre-mixed surfactant emulsion is prepared.

Two formulations, L and M, having the same composition as in Example 2, were prepared except that the amount of stearic acid was increased from 0.1% to 0.2% as revealed in Method A for formulation L and by the following Method C for formulation M. Method C:

The process of Method A is repeated in all its details, except that the emulsion premixture of the surfactants is prepared at ambient temperature and not heated before being added subsequently to the thickened dispersion of &quot; Carbopol &quot;; containing silicate, builders and bleaching agent. The rheograms for the formulations L and M are shown in Figures 11 and 12, respectively. From these rheograms it is seen that the formulation L is linear viscoelastic in both G 'and G', whereas the formulation M is not linear viscoelastic, in particular for the elastic modulus G '(G' at 1% G-tension ' at 30% tension> 50 N / m 2 (500 dynes / cm 2)) and also for G &quot; (1% G-voltage at 30% tension = 30 N / m 2 (300 dynes / cm 2)).

Formulation L remains stable after storage at RT and 38øC (100øF) for at least 6 weeks, while formulation M undergoes phase separation.

Comparative Example 1

The following formulation is prepared without any potassium salts:% by weight Water To make &quot; Carbopol 941 &quot; 0.2 NaOH (50%) 2.4 TPF, Na (50%) 21.0 Na Silicate (47.5%) 17.24 Bleaching Agent (1%) 7.13 Stearic Acid 0.1 LPKN (5 %) 3.2 &quot; Dowfax 3B2 &quot; 0.8 Calcined Soda 5.0 &quot; Acrysol LMW 45-N &quot; 2.0 The procedure used is analogous to that of Method A of Example 2 being added the calcined soda and &quot; Acrysol LMW 45-N &quot; (low molecular weight polyacrylate polymer) before and after, respectively, the silicate, TPF and bleaching agent, to the thickened dispersion of &quot; Carbopol 941 &quot;, followed by the addition of the heated surfactant emulsion premix. The rheogram is shown in figure 13 and is nonlinear with G "/ Gr (tg 5) &gt; 1 in the voltage range of 5% to 80%

Example 4

The formulations A, B, C, D and K prepared according to this invention and comparative formulations F and a commercial automatic dishwasher detergent product, as disclosed in Table 1 above, were subjected to a residue test in bottle, using a standard 28-ounce polyethylene bottle, which corresponds to a bottle normally used for commercial dishwashing liquid detergents.

Six bottles were filled with respective samples and the product was distributed, with a minimum of force, in dosages of 80 grams, with a 2 minute rest period between dosages, until the flow stops. At this point, the bottle was vigorously stirred in an attempt to expel additional product. The amount of product remaining in the bottle was measured, representing a percentage of the total product originally introduced into the bottle. The results are shown below.

Waste in the bottle

Formulation Residue A 8 B 10 C 6 D 5 K 7 * F 4 Commercial Product 20 * The sample separates with aging.

Example 5 -

The following formulas A-B were prepared according to the procedure of Example 1. &quot; Carbopo1614 &quot; 1.0 1.0 &quot; K-7058N &quot; 0 4.0 NaOH (50%) 4.5 4.5 LPKN 158 3.2 3.2 Stearic Acid 0.1 0.1 &quot; Dowfax 3B-2 &quot; 0.8 0.8 Sodium silicate (47.5%) 20.83 20.83 Potassium tripolyphosphate 20.35 20.35 Sodium tripolyphosphate 5.26 5.26 Sodium hypochlorite (13%) 9.2 9 , 2 Water A perf. The perf. &quot; Highlight # 3 &quot; 0.03 0.03 &quot; Cl Green Pigment # 7 &quot; 0.03 0.03. . 1 Unstable Stability2 Stays Sept.

Physical Stability Test

200 ml of the composition was placed in a clear plastic bottle which was stored on a window shelf in daylight with western exposure to the sun at a temperature of 85øF -90øF (29øC-32øC ) for a period of three days. Samples were visually observed for any liquid phase separation and the height of the layer separated at the bottom was measured in case of phase separation. 2

A bottom layer of one cm formed after three days.

J. PEREIRA DA CRUZ

Official Agent of Industrial Property RUA VICTOR CORDON, 10-A 3 "1200 LISBOA

Claims (2)

I. A linear, viscoelastic, aqueous liquid detergent composition for automatic dishwashing machine, comprising: (a) from 10 to 35% of at least one alkali metal detergent builder salt, the composition being said alkali metal detergent builder salt selected from the group consisting essentially of alkali metal tripolyphosphate, alkali metal pyrophosphate, alkali metal metaphosphate, alkali metal carbonate, alkali metal citrate, and alkali metal nitrile triacetate and mixtures thereof; (b) 5 to 15% alkali metal silicate; (c) 0.1 to 3.0% of water-dispersible organic detergent active material stable in the presence of chlorine bleaching agent; (d) 0 to 1.5% of chlorine bleach stable suds suppressor; (e) chlorine bleaching compound in an amount sufficient to provide 0.2 to 4% available chlorine; (f) 0.1 to 2.0% of a cross-linking polyacrylic acid thickening agent having a molecular weight of 1,000,000 to 4,000,000; (g) 0.2 to 2% of a long chain fatty acid or a metal salt of a fatty acid; (h) 0.1 to 10% of a polymeric chelating agent having a molecular weight of 1000 to 20,000; and (i) water, and in that said polyacrylic acid thickening agent is selected from the group consisting essentially of acrylic acid or methacrylic acid, water-dispersible or water-soluble salts, esters or amides thereof, and copolymers of these acids or their salts, esters or amides in combination with one another or with one or more other ethylenically unsaturated monomers and in that the aqueous phase includes both sodium ions and potassium ions in a weight ratio of K / Na from 1/1 to 45/1, for almost all of the normally solid components of the composition are present dissolved in the aqueous phase, and almost all of the water in the composition is firmly attached to the cross-linking polyacrylic acid thickening agent, said composition 3 3 has a density of 1.32 g / cm @ -1 at 1.42 g / cm2 and said composition has no phase separation and remains homogeneous when it is centrifuged at 1000 rpm for 30 minutes. 2δ. Composition according to Claim 1, characterized in that said alkali metal structuring salt is a mixture of sodium tripolyphosphate and potassium tripolyphosphate. 3s. Composition according to Claim 1, characterized in that said alkali metal structuring salt is a mixture of sodium tripolyphosphate and potassium pyrophosphate. 4a. Composition according to Claim 1, characterized in that said alkali metal structuring salt is a mixture of sodium tripolyphosphate, potassium tripolyphosphate, and potassium pyrophosphate and the mixture thereof. 5a. Composition according to Claim 1, characterized in that it further comprises up to 2% by volume, based on the total volume of the composition, of air in the form of finely dispersed bubbles. Composition according to Claim 1, characterized in that the chlorine bleaching compound is sodium hypochlorite. 7a. The composition of claim 1, wherein the polymer chelating agent is a non-crosslinked sodium polyacrylate polymer. 8a. Composition according to claim 1, characterized in that it further comprises a fragrance. The composition of claim 1, further comprising a dye substance or pigment. Lisbon, May 29, 1992 J. PEREIRA DA CRUZ Official Agent of Industrial Property RUA VtCTOR CORDON. 10-A 3. "1200 LISBON