AU611496B2 - Thixotropic aqueous liquid automatic dishwashing detergent composition - Google Patents

Description

ucnaea rnis zbtn day of October 1988 COLGATE-PALMr&IVE C Q9PANY By:e Registered Patent Attorney To: The Commissioner of Patents COMMONWEALTH OF AUSTRALIA COMMONWEALTH OF AUSTRA I l Patents Act 1952 C OMP L E T E S P E C I FP I C A T I O N

(ORIGINAL)

Application Number Lodged Complete Specification Lodged Accepted Published Priority S 28 October 1987 Related Art Name of Applicant Address of Applicant 00q 130. 0 o o o 00 0 o -00 0 0 o o o 0 00 oo ao o 0 0 0 0 0 00 0 0 0 0 0 00 0 00 0 0 0 0 a00 0 0 0 o 00 0000 0 0 0000 0 a 0 004 t a 00 0 COLGA'E-PALMOLIVE COMPANY 300 Park Avenue, New York New York 10022, United States of America Fahim U. Ahmed Charles E. Buck F.B. RICE CO.

Patent Attorneys 28A Montague Street, Balmain N.S.W. 2041 Actual Inventor/s Address for Service Complete Specification for the invention entitled: Thixotropic aqueous liquid automatic dishwasing detergent composition The following statement is a full description of this invention including the best method of performing it known to us? kM I I If Ii

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*1i ij~ o 0 00 0 0 0 o 0 00 0 0 0 FIELD OF THE INVENTION The present invention relates to a thixotropic aqueous liquid automatic dishwashing detergent composition with Improved anti-filming and anti-spotting properties and method of using the detergent composition to clean dishware, glassware, china and the like. The dishwashing composition contains silica, as the anti-filming agent. polyacrylic acid polymer builder Inorganic builder salts, chlorine bleach, bleach stable detergent and a thixotropic tic.'tener.

The detergent dishwashing composition of the preq~nt invention reduces filming and spotting on dlshware, glassware, china and the like.

particularly in hard water, and remains stable against phase separation.

More specifically, th~e invention relates to the use of silica as an anti-filming agent and polyacrylic acid polyn',*7r builder in ihixotropic aqueous liquid dishwashing detergent compositions to reduce filming and spotting, The detergent compositions do no require an added rinse aid, are stable in storage, do not settle and are readily redispersible and are pour able.

The present invention also relates to thixotropic aqueous suspension with improved physical stability. The invention relates to the use of long chain fatty acids, metal salts of fatty acids and clay as thixotropic agents for forming stable gel-like liquid suspensions suitable for use as liquid automatic dishwasher detergent composition.

The present invention specifically relates to aqueous liquid automatic dishwashing detergent compositions having thixotropic properties, improved anti-filming and anti-spotting properties and improved physical stability

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properties, which are readily dispersible in the washing medium to provide effective cleaning of dishware, glassware, china and the like.

PRIOR ART Commercially available household-machine dishwasher detergents provided in powder form have several disadvantages, e.g. non-uniform composition; costly operations necessary in their manufacture; tendency to cake in storage at high humidities, resulting in the formation of lumps which are difficult to disperse; dustiness, a source of particular irritation to users who suffer allergies; and tendency to cake in the dishwasher machine dispenser. Liquid forms of such compositions, however, generally cannot be used in automatic dishwashers due to high foam levels, unacceptably low viscosities and exceedingly high alkalinity.

In addition, the presently used formulated powder detergents frequently require a separate step of hand towel wiping and drying of the dishware, glassware, china and the like to avoid leaving undesirable traces or film of precipitated calcium and magnesium salts. The use of liquid detergnt compositions present other problems. The builder salts settle in storage and are not readily redispersed. The compositions also frequently become thicker in storage and are not readily pourable.

Recent research and development activity has focused on the gel or "thixotropic" form of such compositions, however, such compositions have generally proven to be insufficiently viscous to remain "anchored" in the dispenser cup of the dishwasher, and moreover yield spotty residues on dishware, glassware, china and the like. Ideally, thixotropic cleansing compositions should be highly viscous in a quiescent state, Bingham plastic in nature, and have relatively high yield values. When subjected to shear stresses, however, such as being shaken in a container or squeezed through an orifice, they should quickly fluidize and, upon cassation of the applied shear stress, quickly revert to the high viscosity/Bingham plastic o o o 00 0 0 0 0 o o o 00 0 00 0 00 0o o 0000 0 0 0 0o 1 0 a o t I t L l state. Stability is likewise of primary importance, i.e. ,!here should be no significant evidence of phase separation or leaking after long standing.

For effective use, it is generally recommended that the automatic dishwashing detergent, hereinafter also designated ADD, contain sodium tripolyphosphate (NaTPP) to sofieii or tie up hard-water minerals and to emulsify and/or peptize soil; sodium silicate to supply the alkalinity necessary for effective detergency and to provide protection for fine china glaze and pattern; sodium carbonate, generally considered to be optional, to enhance alkalinity; a chlorine-releasing agent to aid in the elimination of soil specks which lead to water spotting; and defoamor/surfactant to reduce foam, thereby enhancing machine efficiency and supplying requisite detergency. See, for example, SDA Detergents in Depth, "Formulations Aspects of machine Dishwashing," Thomas Oberle (1974). Cleansers approximating to the afore-described compositions are mostly liquids or powders. Generally, such compositions omit hypochlorite bleach, since it tends to react with other chemically active ingredients, particularly surfactant, thereby degrading the suspending or thixotropic oO agent and impairing its effectiveness.

Thus, U.S. Patent No. 3,985,668 describes abrasive scouring cleaners of gel-like consistency containing suspending agent, preferably -he o0 Smectite and attapulgite types of clay; abrasive, e.g. silica sand or 00 0 perlite; and filler comprising light density powdered polymers, expanded perlite and the like, which has a bouyancy and thus stabilizing o00 effect on the composition in addition to serving as a bulking agent, thereby .5 replacing water otherwise available for undesired supernatant layer formation due to leaking and phase destabilization. The foregoing are the o essential ingredients. Optional ingredients include hypochlorite bleach, bleach stable surfactant and buffer, e.g. silicates, carbonates, and 0 0 0o. monophosphates. Builders, such as NaTPP, can be included as further °30 optional ingredients to supply or supplement building function not provided 3 r :I 0 o° 0 o 0 a 00 0 0 0 o 0 0 00 0 0 S0 000 0 00 000 0 0 000 o 00 0 0 0 0 00 00 0 0 3 0 by the buffer, the amount of such builder not exceeding 5% of the total composition, according to the patent. Maintenance of the desired (greater than) pH 10 levels is achieved by the buffer/builder Jomponents. High pH is said to minimize decomposition of chlorine bleach and undesired interaction between surfactant and bleach. When present, NaTPP is limited to as stated. Foam killer is not disclosed.

In U.K. Patent Application GB 2,116,199A and GB 2,140,450A, both of which are assigned to Colgate-Palmolive, liquid ADD compositions are disclosed which have properties desirably characterizing thixotropic, gel-type structure and which include each of the various ingredients necessary for effective detergency with an automatic dishwasher. The normally gel-like aqueous automatic dishwasher detergent composition having thixotropic properties includes the following ingredients, on a weight basis: 5 to 35% alkali metal tripolyphospnate; 2.5 to 20% sodium silicate; 0 to 9% alkali metal carbonate; 0.1 to 5% chlorine bleach stable, water disperLible organic detergent active material; 0 to 5% chlorine bleach stable foam depressant; chlorine bleach compound in an amount to provide about 0.2 to 4% of available chlorine; thixotropic thickener in an amount sufficient to provide the composition with thixotropy index of about 2.5 to 10; and sodium hydroxide, as necessary, to adjust pH.

ADD compositions so formulated are low-foaming; are readily soluble in the washing medium and most effective at pH values best conducive to' improved cleaning performance, viz, pH 10.5-13.5. The compositions are normally of gel consistency, i.e. a highly viscous, opaque jelly-like material having Bingham plastic character and thus relatively high yield values.

4 such as would obtain within the agitated dispenser cup of an energized automatic dishwasher. Under such conditions, the composition is quickly fluidized and easily dispersed. When the shear force is discontinued, the fluid composition quickly reverts to a high viscosity, Bingham plastic state closely approximating its prior consistency.

U.S. Patent 4,511,487 dated April 16, 1985 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 thickening agent which is a foliated silicate of the hectorite type.

Small amount of nonionic tensides and alkali metal carbonates and/or hydroxides may be used.

A related copending application which is assigned to the common assignee is Serial No. 816,535, filed January 7, 1987 which is incorporated herein in Its entirety by reference thereto. The copending application discloses thixotropic aqueous automatic dishwashing detergent composition which contains a long chain fatty acid as a thixotropic thickener agent.

Another related copending application which is also assigned to the o° common assignee is Serial No. 924,385 filed October 29, 1986 which is o incorporated by reference. This copending application discloses an aqueous o 2 0 liquid thixotropic clay dishwashing detergent composition comprising a metal salt of a long chain fatty acid and a polyacrylic acid polymer or salt 0 O* 0 o stabilizing agent.

ADVANTAGES OVER THE PRIOR ART 0o 00 The thixotropic aqueous liquid detergent compositions of the present invention overcome many of the prior art problems associated with powder and liquid detergents. Because of the addition of a small effective amount of a silica anti-filming age~,t and polyacrylic acid polymer or salt builder to the composition an added rinse aid is not required and towel wiping and drying are not required to obtain dry sparkling clean dishes, glasses, cups and eating utensils. The thixotropic aqueous liquid detergent, composition I I r has the additional advantages of being stable, non-settling in storage and readily redispersible. The liquid compositions of the present invention are easily pourable, easily measured and easily put into the dishwashing machines.

An additional and unexpected advantage of adding the silica anti-filming agent to the detergent formulation is that the silica inhibits brown stain formation in the dishwashing machine. The brown stain is formed by the deposition in the dishwashing machine of iron and/or managanese oxides. The brown stain formation is a particularly serious problem in areas having hard water. The silca in the formulation acts on the iron and/or manganese in the wash water to prevent their deposition in the dishwashing machine as iron and/or maganese oxides.

OBJECTS OF THE PRESENT INVENTION It is an object of the present invention to provide a thixotropic aqueous liquid automatic dishwasher detergent composition that has improved anti-filming and anti-spotting properties.

It is another object of the invention to provide a thixotropic aqueous liquid detergent composition which is stable in storage, easily pourable and readily dispersible in the dishwashing water.

A further object of the invention is to provide a method of washing dishware, glassware, china and the like in an automatic dishwashing machine using a thixotropic aqueous liquid detergent composition in which a separate rinse aid is not added or needed.

A still further object of the invention is to provide a method of washing dishware, glassware, china and the like in an automatic washing machine using an aqueous liquid deter:lnt composition by which method the dishware, glassware, china and the like are machine dried without leaving traces or a film.

It is a further object of this invention to provide stable aqueous thixotropic aqueous liquid compositions, especially automatic dishwasher 6 o°un So 0 0. o

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\r 0 oooo o 0 So oo o oI 31a .0 6 detergent compositions, by incorporating in the aqueous suspension a small effective amount of a silica anti-filming agent and polyacrylic acid polymer or salt builder. There is also added a minor amount of a fatty acid, metal salt of a fatty acid and/or clay thixotropic thickener effective to inhibit the settling of the suspended particles and to prevent phase separation.

DETAILED DESCRIPTION OF THE INVENTION These and other objects of the invention which will become more readily understood from the following detailed description of the invention and preferred embodiments thereof are achieved by incorporating in an aqueous liquid detergent composition a small but effective amount of a silica anti-filming agent and polyacrylic acid polymer or salt buildr. The phys'ical stability of the composition is improved by the addition of a fatty acid, metal salt of a fatty acid and/or clay thixotropic thickener. More particularly, according to a preferred and specific embodiment of the invention, there is provided a normally gel-like automatic dishwasher detergent composition it. which is incorporated from about 0.5 to 5% of a silica anti-filming agent and about 2 to 14% of a water soluble polyacrylic acid polymer or salt builder. The silica anti-filming agent has a particle ol 1 size of about 0.1 to 10 microns. The water polyacrylic acid or salt has a S molecular weight of about 500 to 100,000. In a preferred embodiment of the invention there is added to the composition a sufficient amount of a long °chain fatty acid or metal salt of a long chain fatty acid, or either of the foregoing in admixture with a clay thixotropic thickener to provide a .j o thixotropic index of about 2.5 to 10 and to inhibit settling of the suspended particles, such as alkali metal builder salts, etc.

In accordance with this aspect, the present invention provides a acio normally gel-like aqueous liquid automatic dishwasher detergent composition a0 400 having thixotropic properties which includes, on a weight basis: 5 to 35% alkali metal tripolyphosphate; 3'0 2.5 to 40% sodium silicate; I e II I 200, o 0 00 0 0 0 00 0 0.5 to 5% silica anti-filming agent; 2 to 14% polyacryllc acid polymer or salt builder; 0 to 9 alkali metal carbonate; 0.1 to 5% chlorine bleach stable, water dispersible organic detergent active material; 0 to 5% chlorine bleach stable foam depressant; chlorine bleach compound in an amount to provide about 0.2 to 4% of available chlorine; thixotropic thickener In an amount sufficient to provide a thixotropic index of about 2.5 to 0 to 8% sodium hydroxide: and Mk balance water.

Also related to this specific as-)ect, the invention provides a method for cleaning dlahware in an automatic dishwashing machine with an aqueous wash bath containing an effective amount of the liquid automatic dishwasher detergent (LADD) composition as described above. According to this aspect of the invention, the LADD composition can be readily poured into the dispensing cup of the automatic dishwashing machine and will, within just a few seconds, promptly thicken to its normal gel-like or pasty state to remain securely within the dispensing cup until shear forces are again applied thereto, such as by the water spray from the dishwashing machine.

The invention will now be described In greater detail by way of specific embodiments thereof.

The LADD products of for example the prior disclosure in the aforementioned GB 2,116,199A and GB 2,140,450A exhibit rheological properties as evaluated by testing product viscosity as a function of 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 gellation well within the shear rates extant within the standard dishwasher machine. In practical terms, this means improved i pouring and processing characteristics as well as less leaking in the machine dispenser-cup, compared to prior liquid or gel ADD products. For applied shear rates corresponding to 3 to 30 rpm, viscosities (Brookfield) correspondingly ranged from about 10,000 to 30,000 cps to about 3,000 to 7,000 cps, as measured at room temperature by means of an LVT Brookfield viscometer after 3 minutes using a No. 4 spindle. A shear rate of 7.4 -1 sec corresponds to a spindle rpm of about 3. An approximate increase in shear rate produces about a 3- to 9-fold reduction in viscosity.

The compositions of the assignee's prior invention thus exhibit threshold fluidizations at lower shear rates and of significantly greater extent in terms of incremental increases in shear rate versus incremental decrease in viscosity, This property of the LADD products of the prior invention is summarized in .erms of a thixotropic index (TT) which is the ratio of the S apparent viscosity at 3 rpm and at 30 rpm. The prior compositions have a TI of from 2 to 10. The LADD compositions should exhibit substantial and 0 0 0 o. quick return to prior quiescent state consistency when the shear force is oo000 .00o discontinued.

0 0 In terms of apparent viscosity, it has been ascertained that so long as the viscosity at room temperature (22°±1 0 C) measured in a Brookfield Viscosimeter HATD, using a number 4 spindle at 20 rpm, is less than about o S o a 20,000 cps, the composition can be readily shaken so that a thixotropic 0 0 0 o00 0 composition can be easily "fIuidized' or "liquefied" to allow the product to OO 00 o o 0 0 o be dispensed through a conventional squeeze tube bottle or other convy....nt dispenser.

The present invention is based upon the surprising discovery that o 0 S0 substantially improved anti-filming and anti-spotting properties can be obtained by adding to the thixotropic aqueous liquid detergent composition a small effective amount of a silica anti-filming agent and polyacrylic acid polymer or salt builder. The physical stability, resistance to phase R,4

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separation, settling, etc. can be achieved by adding to the composition a small effective amount of a thixotropic thickener and stabilizing agent.

ANTI-FILMING AGENTS The silica anti-filming agent materials that can be used are fumed or precipitated synthetic or natvual silica. The silica may be amorphous or crystalline.

The silica material that is used may contain up to about 0.1 to alumina (Al 0 3 usually up to about 0.5 to 3% and more usually about 1% alumina, based on the weight of silica.

A preferred silica material is Syloid 244 which is amorphous silica and i-o provided by Another preferred silica material is Huber Zeo 49 which is amorphous silica and is provided by J.M. Huber Corporation and contains about 1% alumina (A120 3 The presence of as little as 1% AIO0 3 is found to help reduce the hydrolysis and subsequent solubility of the silica in the highly alkaline automatic dishwashing detergent composition.

The particle size of the filica material that is used is important in achieving the desired anti-filming properties.

The silica particles that are used are finely divided and can have a particle size of about 0.10 to 10 microns, preferably 0.50 to 8 microns and more preferably about 1.0 to 5.0 microns. The silica particles of this size and in the amount used herein are not abrasive.

The finely divided silica material particles in the dishwashing wash act to coagulate proteinaceous particulate soils and keeps them in suspension and with the polyacrylic acid polymer or salt acts as an anti-redeposition agent to prevent them from depositing on the clean glass and dishware.

The amount of silica anti-filming agent that can be used to achieve the deFired improvement in filming and spotting will depend on the hardness of the water, detergent active compound, inorganic salts and other ADD 0o o a o o 0 00 S0 0 0 00 0 000 00 S0 o0 I* o t a I 4 i 01* I t 00 06 0

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t o o a o o o o o 0000 00 0 o oaaa b ingredients. The silica anti-filming agent is '-articularly effective in hard wash water of, for example, 300 ppm hardness or more.

The amount of silica anti-film agent that is used can be about 0.5 to preferably about 1 to 4% and more preferably about 1.5 to 3% by weight based on the weight of the entire composition.

POLYACRYLIC ACID POLYMERS AND SALTS THEREOF The polyacrylic acid polymers and salts thereof that can be used are generally commercially available and are briefly described as follows.

The polyacrylic acid polymers and salts thereof that can be used comprise water soluble low molecular weight polymers having the formula R 1

R

C-C

R

3

COOM

wherein the R 1

R

2 and R 3 can be the same or different and can be hydrogen, CI-C 4 lower alkyl, or combinations thereof. The value of n is to 1000, preferably, 10 to 500, and more preferably 20 to 100. M represents hydrogen, or an alkali metal such as sodium or potassium. The preferred substituent for M is sodium.

The preferred R 1

R

2 and R 3 groups are hydrogen, mety,, nthyl and propyl. Preferred acrylic acid monomer is one where R 1 to R 3 are hydrogen, e.g. acrylic acid, or where R 1 and R 3 are hydrogen and R, is methyl, e.g. methyl acrylic acid monomer.

The degree of polymerization, i.e. the value of n, is generally determined by the limit compatible with the solubility of the polymer in water. The terminal or end groups of the polymer are not critical and can be H, OH, CH 3 or a low molecular weight hydrocarbon.

The polyacrylic acid polymers and salts thereof can have a molecular weight of 500 or 1,000 t 100,000, preferably 1,500 to 50,000 and especially preferably 2,000 to 10,000.

0 o o o 0 0 0 00oo 0 00 0 0 00 0 oo 0 00 ao o o 0 0 0 8" s -:a r x i 1 c

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I II n- COmpU6.LLJU' jUUIIII.LiLy n J.Y' "^y 5 to 35% detergent b'iilder; 2.5 to 40% sodium silicate; 0.5 to 5% of silica anti-filming agent having a particle size of 0.1 to 10 microns; /2 Specific polyacrylic acid polymers which can be used include the Acrysol LMW acrylic acid polymers from Rohm and Haas, such as the Acrysol LMW-45NX, a neutralized sodium salt, which has a molecular weight of about 4,500 and Acrysol LMW-20NX, a neutralized sodium salt, which has a molecular weight of about 2,000. The low molecular weight acrylic acid polymers can, for example, have a molecular weight of about 1.000 to 10,000. Another polyacrylic acid polymer that can be used is Alcosperse 110 (from Alco) which is a sodium salt of an organic polycarboxylate and which has a molecular weight of about 100,000.

The above polyacrylic acid polymers and salts thereof can be made using procedures known in the art, see for example U.S. Patent 4,203,858.

The amount of polyacrylic acid polymer or salt builder that can be used to achieve the desired improvement in anti-filming and anti-spotting Sproperties will depend on the hardness of the water, detergent active compound, inorganic salts and other ADD ingredients.

The polyacrylic acid or salt builder is particularly effective in reducing spotting in hard water of, for example, 300 ppm hardness or more.

Generally, the amounts of the polyacrylic acid polymer or salt that can o1O be used are in the range of from about 2.0 to 14%, preferably from about to 12%, especially preferaoly about 4 to t* THIXOTROPIr THICKENF.RS The thixotropic thickeners or suspending agents that can be used in V i o' accordance with the present invention to provide the aqueous medium with thixotropic properties may be organic, for example, fatty acid or fatty acid polyvalent metal salts or inorganki colloid forming clay materials. The thixotropic thickeners should stable to high alkalinity and stable to chlorine bleach compounds such as bodium hypochlorite. The preferred thixotropic thickeners compriss the fatty acids, the fatty acid polyvalent metal salts dnd the inorganic, colloid-forming clays of smectite and/or 1 i i attapulgite types. The amount of the thixotropic thickener used will depend on the particular thickener used, but sufficient thickener is added to the formulation to provide the composition with a thlxotropy index of about 2.5 to The preferred fatty acid thixotropic thickeners are the higher aliphatic fatty monocarboxylic acids having from about 8 to about 22 carbon atoms, more preferably from about 10 to 20 carbon atoms, and especially preferably from about 12 to 18 carbon atoms, inclusive of the carbon atom of the carboxyl group of the fatty acid. The aliphatic radical may be saturated or unsaturated and may be straight or branched. Straight chain saturated fatty acids are preferred. Mixtures of fatty acids may be used, such as those derived from natural sources, such as tallow fatty acid, coco fatty acid, soya fatty acid, etc., or from synthetic sources available from industrial manufacturing processes.

Thus, examples of the fatty acids which can be used as thickeners include, for example, decanoic acid, lauric acid, dodecanoic acid, palmitic acid, myristie acid, stearic acid, oleic acid, etcosanoic acid. tallow fatty oo °o acid, coco fatty acid, soya fatty acid and mixtures of these acids. S3daric °o acid and mixed fatty acids, e.g. coco fatty acid, are preferred.

0O o oo 0 The amount of the fatty acid thickener to achieve the desired values of thixotropy and physical stability will depend on such factors as the nature o o of the fatty acid, detergent active compound, inorganic salts, especially TPP, other LADD ingredients, well as tihe anticipated storage and S shipping conditions.

0 00 Generally, however, amounts of the fatty acid thixotropic agent that can be used are in the range of from about 0.03 to preferably from about 0.03 to especially preferably from about 0.05 to 0.15%, provide g o, the desired long term stability and absence of phase separation.

oS The polyvalent metal salts oi the above fatty acids can also be used in the present invent'on as thixotropic thickener agents. Suitable metal salt .13 i o 40 4, 4 464 0C I U inciualng the best method of performing it known to usfW:r;7 r~A0 o ,oo 00 0 o o o 04 040 0 0 0 0 000 00000 o0 0 0 0 0 00 0 00 0000 0 0 0600 0 0 o o co oo° 0 0 0 o 0o S30 0 0 0 thixotropic thickeners are disclosed in the prior application Serial No.

903,924 filed September 5, 1986 in the name of Drapier et al., which is incorporated herein in its entirety by reference thereto.

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

Generally, the metals may be present in the divalent to pentavalent state. Preferably, the metal salts are used in their higher oxidation states.

Naturally, for LADD compositions, as well as any other applications where the invention composition will or may come into contact with articles used for the handling, storage or serving of food products or which otherwise may come into contact with or be consumed by people or animals, the metal salt should be selected by taking into consideration the toxicity of the metal. For this purpose, the calcium and magnesium salts are especially highly preferred as generally safe food additives.

Many of these metal salts are commercially available. For example, the aluminum salts are available in the triacid form, e.g. aluminum stearate as aluminum tristearate, AI(C 1 7

-H

3 5

COO)

3 The monoacid salts, e.g. aluminum monostearate, AI(OH) 2

(C

1 7

H

3 5 COO) and diacid salts, e.g. aluminum distearate, Al(OH)C 1 7

H

3 5

COO)

2 and mixtures of two or three of the mono-, di- and tri-acid salts can be used for those metals, e.g. Al, with valences of and mixtures of the mono- and di-acid salts can be used for those metals, e.g. Zn, with valences of It is more preferred that the diacids of the +2 valent metals and the triacids of the +3 valent metals, the tetraaids of the +4 metals, and the pentacids of the +5 valent metals, be used in predominant amounts. For example, at least 30%, preferably at least 50%, especially preferably from 80 to 100% of the total metal salt should be In the highest possible oxidation state, i.e. each of the possible valence sites is occupied by a fatty acid residue.

The metal salts, as mentioned above, are generally commercially available but can be easily produced by, for example, saponification of a 14 o 00 0 00 00o o 7MOW-

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S VIf oo0 0 00 00 0 o o o 9 00 0' 4 0 4 oo i 4 i o t fatty acid, e.g. animal fat, stearic acid, etc., or the corrasponding fatty acid ester, followed by treatment with an hydroxide or oxide of the polyvalent metal, for example, in the case of the aluminum salt, with alum, alumina, etc.

Calcium stearate, i.e. calcium distearate, magnesium stearate, i.e.

magnesium distearate, aluminum stearate, i.e. aluminum tristearate, and zinc stearate, i.e. zinc distearate, are the preferred polyvalent fatty acid salt stabilizers. Mixed fatty acid metal salts, such as the naturally occurring acids, e.g. coco acid, as well as mixed fatty acids resulting from the commercial manufacturing process are also advantageously used as an inexpensive but effective source of the long chain fatty acid.

The amount of the fatty acid salt stabilizers to achieve the desired enhancement of physical stability will depend on such factors as the nature of the fatty acid salt, the nature and amount of the thixotropic agent, detergent active compound, inorganic salts, especially TPP, other L. DD ingredients, as well as the anticipated storage and shipping conditions.

Generally, however, amounts of the polyvalent metal fatty acid salt stabilizing agents in the rang( of from about 0.02 to preferably from about 0.06 to especially preferably from about 0.08 to provide the long term stability and absence of phase separation upon standing or during transport at both low and elevated temperatures as are required for a commercially acceptable product.

There may also be used in the present invention the conventional inorganic thixotropic clay thickeners. The clay thickeners may be used in small amounts in combination with the fatty acid thickeners or in combination with fatty acid polyvalent metal salt thickeners. The clay thickeners, however, may be used by themselves as the thixotropic thickeners.

The prefer' id clay thickeners comprise the inorganic, colloid forming clays of smer, ind/or attapulgite types.

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through an orifice, they should quickly fluidize and, upon 4assation of the applied shear stress, quickly revert to the high viscosity/Bingham plastic 2 ff Smectite clays include montmorillonite (bentonite), hectorite, attapulgite, smectite, saponite, and the like. Montmorillonite clays are preferred and are available under trndenames such as Thixogel (Registered Trademark) No. 1 and Gelwhite (Registered Trademark) GP, H, etc., from Georgia Kaolin Company; and Eccagum (Registered Trademark) GP, H, etc., from Luthern Clay Products. Attapulgite clays include the materials commercially available under the tradename Attagel (Registered Trademark), i.e. 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 are also useful herein. Thickening or suspending agents of the foregoing types are well known in the art, being described, for example, in U.S. Patent No. 3,985,668 referred to above. Abrasives or polishing agents should be avoided in the LADD compositionn as they may mar the surface of fine dishware, crystal and the like.

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

o 0o o °0 i When the clay thixotropic thickeners are used alone as the thixotropic 00oo 0, S 20 thickener agent they can be used in amounts of about 1.5 to preferably 2 to 5% by weight of the formulation.

01 0 0 0 0 0 0 Generally, LADD effectiveness is directly related to available chlorine levels; alkalinity; solubility in washing medium; and (d) 0 00 0 0 0 °0 foam inhibition. It is preferred herein that the pH of the LADD composition o o0 4 be at least about 9.5, more preferably from about 10.5 to 13.5 and most b ooo* preferably at least about 11.5. At the relatively lower pH values, the 0 LADD product is too viscous, i.e. solid-like, and thus not readily fluidized t under the shear-force levels created within the dispenser cup under normal machine operating conditions. Addition of NaOH is thus often needed to increase the pH to within the above ranges, and to increase flowability S16 a1iL. upulonal Ingredients include hypochlorite bleach, 1 bleach stable surfactant and buffer, e.g. silicates, carbonates, and o0 0 monophosphates. Builders, such as NaTPP, can be included as further E" optional ingredients to supply or supplement building function not provided

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properties. The presence of carbonate is also often needed herein, since it acts as a buffer helping to maintain the desired pH level. Excess carbonate is to be avoided, however, since it may cause the formation of needle-like crystals of carbonate, thereby impairing the stability, thixotropy and/or detergency of the LADD product, as well as impairing the dispensibility of the product from, for example, squeeze tube bottles. Caustic soda (NaOll) serves the further function of neutralizing the phosphoric or phosphonic acid ester foam depressant when present. About 0.5 to 3 wt% of NaOH and about 2 to 9 wt% of sodium carbonate in the LADD composition are typical, although it should be noted that sufficient alkalinity may be provided by the NA:i'PP and sodium silicate.

Th NaTPP may be employed in the LADD composition in a range of about 8 'o 35 wt%, preferably about 20 to 30 wt%, and should preferably be free of heavy metal which tends to decompose or inactivate the preferred sodium hy)ochlorite and other chlorine bleach compounds. The NaTPP may be anhydrous or hydrated, including the stable hexahydrate with a degree of hydration of 6 corresponding to about 18% by weight of water or more.

o o Actually, in view of the stability of the hexahydrate, the presence of some water of hydration is highly effective, serving it is thought to form seeds S2 of the stable hexahydrate which expedites hydration and solubilization of 0 the remaining NaTPP particles. If only the hexahydrate is used, the detergent product may be too liquid. Conversely, if only the anhydrous NaTPP is used, the product may, in some cases, be too thick and, Stherefore, unsuitable. Especially preferred LADD compositions are obtained, for example, when using a 0.5:1 to 2:1 weight ratio of anhydrous to hexahydrated NaTPP, values of about 1:1 being particularly preferred.

o Foam inhibition is important to increase dishwasher machine efficiency and minimize destabilizing effects which might occur due to the presence of S excess foam within the washer during use. Foam may be sufficiently reduced by suitable selection of the type and/or amount of detergent active 17 normally of gel consistency, i.e. a highly viscous, opaque jely-like material having Bingham plastic character and thus relatively high yield values.

S3. Accordingly, a definite shear force is necessary to initiate or increase flow, 1 4 material, the main foam-producing component. The degree of foam is also somewhat' dependent on the hardness of the wash water in the machine whereby suitable adjustment of the proportions of NaTPP which has a water softening effect may aid in providing the desired degree of foam inhibition.

However, it is generally preferred to include a chlorine bleach stable foam depressant or inhibitor. Particularly effective are the alkyl phosphonic acid esters of the formula 0 o HO- P R

OR

available for example from BASF-Wyandotte (PCUK-PAE), and especially the alkyl acid phosphate esters of the formula 0 HO-P -OR

OR

available, for example, from Hooker (SAP) and Knapsack (LPKn-158), in which one or both R groups in each type of ester may represent a independently a C12-20 alkyl group. Mixtures of the two types, or any o° 15 other chlorine bleach stable types, or mixtures of mono- and di-esters of pg the same type, may be employed. Especially preferred is a mixture of mono- and di-C16 1 8 alkyl acid phosphate esters such as monostearyl/distearyl acid phosphates 1.2/1 (Knapsack). When employed, proportions of 0.01 to 5 wt%, preferably 0.1 to 5 wt%, especially about 0.1 2 0 'o to 0.5 wt%, of foam depressant in the composition is typical, the weight o ratio of detergent active component to foam depressant generally ranging from about 10:1 to 1:1 and preferably about 4:1 to 1:1. Other defoamers which may be used include, for example, the known silicones.

Although any chlorine bleach compound may be employed in the compositions of this invention, such as dichloro-isocyanurate, I dichloro-dimethyl hydantoin, or chlorinated TSP, alkali metal, e.g.

18 'So S-o- j- uu puLymr :r or zat DUlicler to the composition an added rinse aid is not required and towel wiping and drying are not required to obtain dry sparkling clean dishes, glasses, cups and eating utensils. The thixotropic aqueous liquid detergent composition W- I -q potassium, lithium, magnesium and especially sodium hypochlorite is preferred. The composition should contain sufficient chlorine bleach compound to provide about 0.2 to 4.0% by weight of available chlorine, as determined, for example, by acidification of 100 parts of the composition with excess of hydrochloric acid. A solution containing about 0.2 to by weight of sodium hypochlorite contains or provides roughly the same percentage of available chlorine. A solution containing about 0.8 to 1.6% by weight sodium hypochlorite contains about 0.8 to 1.6% by weight of available chlorine and is especially preferred. For example, sodium hypochlorite (NaOCI) solution of. from about 11 to about 13% available chlorine in amounts of about 3 to 20%, preferably about 7 to 12%, can be advantageously used.

The sodium silicate, which provides alkalinity and protection of hard surfaces, such as fine china glaze and pattern, is employed in an amount ranging from about 2.5 to 40 wt%, preferably about 10 to 35 wt%, in the composition. At the higher levels specified herein for examp'a at levels greater than about 10 wt% the silicate also provides increased antispotting action. The sodium silicate is generally added in the form of an aqueous solution, preferably having an Na 2 0:SiO 2 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 foam depressant may also be added in the form of an aqueous dispersion or solution.

Detergent active material useful herein must be stable in the presence of chlorine bleach, especially hypochlorite bleach, and those of the organic anionic, amine oxide, p,,osphine oxide, sulphoxide or. betaine water dispersible surfactant types are preferred, the first mentioned anionics being most preferred. They are used in amounts ranging from about 0.1 to preferably about 0.3 to Particularly preferred surfactants herein are the linear or branched alkali metal mono- and/or di-(C 8 _1 4 alkyl diphenyl oxide raono and/or disulphates, commercially available for example as DOWFAX (Registered Trademark) 3B-2 and DOWFAX 2A-1.

SA a V1 4 1 4 o r e 3t

L

wa, canina a ia ine nKe are machine dried without leaving traces or a film.

is a further object of this invention to provide stable aqueous 3O' thixotropic aqueous liquid compositions, especially automatic dishwasher 6 ~jW-1 In addition, the supfactant should be compatible with the other ingredients of the composition. Other suitable surfactants include the primary alkylsulphates, alkylsulphonates, alkylaryl-sulphonates and sec.-alkylsulphates. Examples include sodium C 1 0 1 8 alkylsulphates such as sodium dodecylsulphate and sodium tallow alcoholsulphate; sodium C10-18 alkanesulphonates such as sodium hexadecyl-1-sulphonate and sodium C 1 2 1 8 alkylbenzenesulphonates such as sodium dodecylbenzenesulphonates. The corresponding potassium salts may also be employed.

As other suitable surfactants or detergents, the amine oxide surfactants are typically of the structure R 2 R NO, in which each R 1 represents a lower alkyl group, for instance, methyl, and R represents a long chain alkyl group having from 8 to 22 carbon atoms, for instance a lauryl, myristyl, palmityl or cetyl group. Instead of an amine oxide, a corresponding surfactant phosphine oxide R 2 R PO or sulphoxide RR SO can be employed. Betaine surfactants are typically of the structure R 2 R N R"COO in which each R represents a lower alkylene group having from 1 to 5 carbon atoms. Specific examples of these surfactants are S* lauryl-dimethylamine oxide, myristyldimethylamine oxide, the corresponding phosphine oxides and sulphoxides, and the corresponding betaines, o 20 including dodecyldimethylammonium acetate, tetradecyldiethylammonium pentanoate, hexadecyl-dimethylanimonium hexanoate and the like. For S" biodegradability, the alkyl groups in lhese surfactants should be linear, and such compounds are 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.

The amount of water contained in these compositions should, of course, be neither so high as to produce unduly low viscosity and fluidity, nor so low as to produce unduly high viscosity and low flowability, thixotropic properties in either case being diminished or destroyed. Such aim.unt is readily determined by routine experimentation in any particular instance, I' 3' having thixotropic properties which includes, on a weight basis: 5 to 35% alkali metal tripolyphosphate; 2.5 to 40% sodium silicate; 7 i, t: Si.

e 'r \i

I

m r.

generally ranging from about 25 to The water should also be preferably of water in the composition Include solutions of other ingredients, but that in NaTPP hexahydrate.

Other conventional ingredients in small amounts, generally less hydrotropic agents such as the sodi sulphonates, preservatives, dyestu course being stable to chlorine (properties of all the components).

the chlorinated phthalocyaninea and provide, respectively, pleasing gree The liquid ADD compositions of known manner for washing dishes, like in an automatic dishwasher, dispenser, in an aqueous wash bat composition.

I

0 it ii 0*a 75 wt%, preferably about 50 to 65 wt%.

deionized or softened. These amounts the water added as parts of the liquid do no include bound water, for example may be included in these compositions than about 3 wt%, such as perfume, um benzene, toluene, xylene and cumene ffs and pigments and the like, all of bleach compound and high alkalinity Especially preferred for coloring are Spolysulphides of aluminosilicate which n and blue tints.

f this invention are readily employed in glasses, cups, eating utensils and the provided with a suitable detergent h containing an effective amount of the !1 I II IS I I S S o. ile compositions exhibited higher viscosity at a low shear rate and lower viscosity at a high shear rate, the data indicating efficient fluidization and gellation well within the shear rates extant within the standard dishwasher machine. In practical terms, this means improved 8 a B 1 1 Ir i 1

I

In a preferred embodiment of the invention the aqueous liquid dishwashing detergent composition is formulated using the below named ingredients.

Component Weight Percent Alkali Metal Tripolyphosphate 10-25 Sodium Silicate 20-40 Silica Anti-filming Agent 1-4 Polyacrylic Acid Polymer or Salt 3-12 Alakli Metal Carbonate (anhydrous) 2-8 Chlorine Bleach Stable, Water Dispersible Organic Detergent A: ive Material 0.5-3 Chlorine Bleach Stabl Foam Depressant 0.10-3 Chlorine Bleach Compound 0.2-4 Fatty Acid Thixotropic Thickener 0.03-0.5 Sodium Hydroxide 2-6 Balance Water The thixotropic aqueous liquid automatic dishwashing detergent compositions of the present invention can contain aconventional dishwashing detergent composition additives. The formulations can be prepared with commercially available solid powder builders, and/or the ingredients can be mixed and the formulations ground to a desired particle size.

The invention may be put into practice in various ways and a number of specific embodiments will be described to illustrate the invention with reference to the accompanying examples.

All amounts and proportions referred to herein are percent by weight of the composition urdess otherwise indicated.

The present invention is further illustrated by the following examples.

I

O0 o0 00 0 0 0i q0 I0*

I

obtained by adding to the thixotropic aqueous liquid detergent composition a small effective amount of a silica anti-filming agent and polyacrylic acid polymer or salt builder. The physical stability, resistance to phase 9 Example 1 A thixotropic aqueous liquid automatic dishwashing detergent composition is formulated from the following ingredients in the amounts specified.

Component Weight Percent Deionized Water 24.05 Knapsack LPKN-158 Foam Depressant 1 0.16 Sodium Hydroxide 5.00 Sodium Carbonate (anhydrous) 5.00 Sodium Tripolyphosphate (anhydro:s) 20.00 Silica Anti-filming Agent 2 Sodium polyacrylate polymer builder 8.00 Stearic Acid Thixotropic Thickener 0.10 Dowfax 3B-2 Surfactant 4 0.80 Sodium Hypochlorite 9.10 Sodium Silicate (1/2.23 47%) 25.29 100.00 Mixture of mono and distearyl (C 1 6

-C

1 8 alkyl esters of phosphoric acid, molk ratio 1:1.3.

Silica SyloAd 244 has a particle size of about 4 microns and is available from Co.

Alcosperse 149, about 2000 mw, available as a 40% solution.

20 Na mono- and didecyl diphenyl ether disulfonate (45% solution).

o The ingredients are added to the water generally in the order listed and gently stirred until a homogeneous mixture is obtained. The o. formulation is tested by washing glassware and dishware at a temperature of o, o t 120 0 F in hard wator (300 ppm hardness) in an automatic dishwashing machine and the clean and dried dishes are found to have no apparent film S and very few apparent spots.

23 The amount of silica anti-filming agent that can be used to achieve the desired improvement in filming and spotting will depend on the hardness of the water, detergent active compound, inorganic salts and other ADD Example 2 In order to demonstrate the effect of adding the Lilica anti-filming agent, formulations ai prepared with and without the silica anti-filming agent and are comp-'ed to a commercially available powder detergent composition.

The compositions are formulated to contain the following ingredients.

A B C Silica/ No Silica/ Silica/No Component Polyacrylate Polyacrylate Polyacrylate Deionized Water 24.05 26.55 32.05 Knapsack LPKN-158 Foam Depressant 0.16 0.16 0.16 Sodium Hydroxide 5.00 5,00 5.00 Sodium Carbonate (Anhydrous) 5.00 5.00 5.00 Sodium Tripolyphosphate (Anhydrous) 20.00 20.00 20.00 Silica (Syloid 244) Anti-filming Agent 2.50 2.50 Sodium Polyacrylate Polymer(1)(A.I.) 8.00 8.00 Stearic Acid Thixotropic Thickener 0.10 0.10 0.10 Dowfax 3B-2 Surfactant 0.80 0.80 0.80 Sodium Hypochlorite 9.10 9.10 9.10 SSodium Silicate (1/2.23 47%) 25.29 25.29 25.29 O 100.00 100.00 100.00 'o Alcosperse 149.

The ingredients are added to the water generally in the order listed and gently stirred until a homogeneous mixture is obtained. The formulation is tested by washing glassware at 120°F in hard water (300 ppm hardness).

SThe three above formulations and were tested and compared with a commercially available powder automatic dishwasher C- detergent formulation D. The formulations were tested in a Kenmore 24.

L

j i=i1L nyarocaroon.

The polyacryiic acid polymers and salts thereof can have a molecular weight of 500 or 1,000 t- 100,000, preferably 1,500 to 50,000 and especially preferably 2,000 to 10,000.

-OEM

automatic dishwvasher using the procedure described in ASTMD 3566-79, except ihat only four cleaning cycles are used. The filming and spotting are evaluated according to the following scales: Film Rating Scale 1. Best, no apparent film 2. Filming slight, becoming apparent 3. Noticeable film, increasing 4. Continued increase of significant film Filming becoming excessive 6. Filming high, excessive buildup 7. Continued Increase of excessive film.

Spot Rating Scale A. Best no spots B. Very few spots apparent C. Distinct D. Significant coverage approximately The results obtained are reported in the below Table 1.

TABLE 1 Formulation Silica/ Polyacrylate No Silica/Polyacrylate Silica/No Polyacrylate Commercial Powder Detergent Performance Rating Spot Film B 1-2 B-C 5-6 B-C 2 B-C 3-4 thixotropic thickeners comprise metal salts and the inorganic, the fatty acids, the fatty acid polyvalent colloid-forming clays of smectite and/or a El^- i-i Example 3 Thixotropic aqueous liquid automatic dishwashing compositions are formulated from the following ingredients in specified.

detergent the amounts 23 S oa E F G Silica/ No Silica/ Silica/No Component Polyalrylate Polyacrylate Polyacrylate Deionized Water 27.64 29.64 32.64 Knapsack LPKN-158 Foam Depressant 0.16 0.16 0.16 Sodium Hydroxide 5.00 5.00 5.00 Sodium Carbonate (Anhydrous) 5.00 5.00 5.00 Sodium Silicate (1/2.35 43.5%) 25.30 25.30 25.30 Sodium Tripolyphosphate (Anhydrous) 20.00 20.00 20.00 Silica Anti-filming Agent 2.00 2.00 Sodium Polyacrylate 2 5.00 5.00 Dowfax 3B-2 Surfactant 3 0.80 0.80 0.80 Stearle Acid 4 0.10 0.10 0.10 Sodium Hypochlorite 9.00 9.00 9.00 100.00 100.00 100.00 Silica (Huber Zeo 49) contains about 1% alumina (AL 2 0 3 and has a particle size of about microns.

LMW 45 N, about 4500 MW, available as a 45% solution of active ingredient.

Na mono and didecyl diphenyl ether disulfonate (45% solution).

Emersol 132 available from Company.

The ingredients are added to the water generally in the order listed and stirred until a homogeneous mixture is obtained. The formulations are tested by washing glassware at 130°F in hard water (300 ppm hardness).

he two formulations were tested and compared to a commercial powder automatic dishwasher detergent formulation H. The formulations were tested in a Kenmore automatic dishwasher using the nrocedure described in ASTMD 3666-79. except that only four cleaning cycles were used. The spotting and filming are evaluated as in Example 2 and the results obtained are reported in below Table o 26 S the desired long term stability and absence of phase separation.

.a i The polyvalent metal salts of the above fatty acids can also be used in the present inveni'on as thixotropic thickener agents. Suitable metal salt .n i13 TABLE 2 Performance Rating Spot Film Silica/Polyacrylate A 2 No Silica/Polyacrylate A 4 SilclaNo Polyacrylate B 2-3 Comme'cial Powder Detergent B-C 5-6 Example 4 A thixotropic aqueous liquid automatic dishwashing detergent composition is formulated from the following ingredients in the amounts specified.

Component Weight Percent Deionized Water 34.79 Aluminum Stearate Thixotropic Thickener 0.25 Clay (Phaymagel H) Thixotrop!i Thickener 1.25 Sodium Silicate (1/2.4 47.5%) 13.73 Sodium Tripolyphosphate (anhydrous) 12.00 Sodium Tripolyphosphate (hexahydrate) 12.00 I" Silica Anti-filming Agent 2.00 Sodium Polyacrylate (MW 2000) 6.00 Sodium Carbonate (anhydrous; 7.00 Sodium Hypochlorite 7.61 Dowfax 3B-2 Surfactant 0.80 Knapsack LPKN-158 Foam Depressant 0.16 Sodium Hydroxide 2.40 Graphitol Green 0.01 100.00 The ingredients are mlxed following the procedure of the copending commonly "ssigned application Serial No. 903,924 filed September 5, 1986, which is incorporated herein in its entirety by reference tie.o.

27 o °The metal salts, as mentioned above, are generally commarcially available but can be easily produced by, for example, saponification of a 14 14 I I The formulation is tested by washing glassware at 130 0 F in hard water (300 ppm hardness) in an automatic dishwashing rmachine. The cleaned and dried glassware are found to have no apparent film and very few apparent spots.

The thixotropic aqueous liquid automatic dishwashing detergent compositions of the present invention provide improved film properties.

The invention is not to be limited by the above disclosu-e and Examples which are given as illustrations only. The invention is to be interpreted in accordance with the below claims.

(i

Claims (18)

1. A gel-like thixotropic aqueous liquid automatic dishwashing detergent composition comprising water, at least one ingredient selected from the group consisting of organic detergent, chlorine bleach, detergent builder, sequestering agent, foam inhibitors, and mixtures thereof, from 0.5 to 5% of a silica anti-filming agent and 2 to 14% of a polyacrylic acid polymer or salt, and a sufficient amount of a thixotropic thickener to provide a thixotropic index of 2.5 to

2. The composition of claim 1 wherein the silica anti-filming is in an amount of 1 to 4% and the polyacrylic acid polymer or salt is in an amount of 3 to 12%.

3. A thixotropic aqueous liquid automatic dishwasher composition comprising by weight: 5 to 35% detergent builder; 2.5 to 40% sodium silicate; 0.5 to 5% of silica anti-filming agent having a particle size of 0.1 to 10 microns; C 2 to 14% polyacrylic acid polymer or salt builder having a molecular weight of 1000 to 100,000; 0 to 9% alkali metal carbonate; 0.1 to 5% chlorine bleach stable, o water-dispersible organic detergent active material; oa 0 to 5% chlorine bleach stable foam depressant; 0o o. chlorine bleach compound in an amount to provide 0.2 to 4% of available chlorine; a sufficient amount of a thixotropic thickener to oo provide a thixotropic index of 2.5 to 0 to 8% of sodium hydroxide; balance water.

4. The composition of claim 3 wherein the polyacrylic acid polymer or salt has the formula R I&J LALAAJ ULI L ylC;I CIHLy Sand minimize destabilizing effects which might occur due to the presence of S excess foam within the washer during use. Foam may be sufficiently reduced by suitable selection of the type and/or amount of detergent active 17 30 -C C R- COOM n wherein R 1 R 2 and R 3 can be the same or different and can be hydrogen, C 1 -C 4 lower alkyl, M represents hydrogen, or an alkali metal, n 5 to 1000 and the polymer has a molecular weight of 1000 to 100,000. The composition of claim 3 wherein the thixotropic thickener comprises a long chain fatty acid in an amount of 0.03 to

6. The composition of claim 3 wherein the thixotropic thickener comprises a polyvalent metal salt of a long fatty acid in an amount of 0.02 to

7. The composition of claim 5 additionally comprising a clay thixotropic thickener in an amount of 0.1 to

8. The composition of claim 6 additionally comprising a 0 clay thixotropic thickener in an amount of 0.1 to

9. The composition of claim 3 wherein the silica anti-filming agent has a particle size of 0.5 to microns. A thixotropic aqueous liquid automatic dishwasher OO composition comprising by weight: o 5 to 35% alkali metal tripolyphosphate; o 2.5 to 40% sodium silicate; 1 to 4% silica anti-filming agent having a particle size of 0.5 to 8.0 microns; S(d) 3 to 12% polyacrylic acid polymer or salt 0 builder; 0 to 9% alkali metal carbonate; 0.1 to 5% chlorine bleach stable, water dispersible organic detergent active material; 0 to 5% chlorine bleach stable foam depressant; I op ouLY en orine bleach compound may be employed in the o compositions of this invention, such as dichloro-isocyanurate, dichloro-dimethyl hydantoin, or chlorinated TSP, alkali metal, e.g. 18 31 chlorine bleach compound in an amount to provide 0.2 to 4% of available chlorine; a sufficient amount of a thixotropic thickener to provide a thixotropic index of 2.5 to 0 to 8% of sodium hydroxide; balance water.

11. The composition of claim 10 wherein the polyacrylic acid polymer or salt has the formula R 1 R -C C R 3 COOM n wherein R 1 and R 3 are hydrogen, and R 2 is hydrogen or methyl, M represents hydrogen, sodium or potassium, n to 500 aind the polymer has a molecular weight of 1500 to 50,000.

12. The composition of claim 10 wherein the polyacrylic acid polymer or salt has a molecular weight of 2000.

13. The composition of claim 10 wherein the polyacrylic acid polymer or salt has a molecular weight of 4500.

14. The composition of claim 10 wherein the silica anti-filming agent contains 0.1 to 5% of alumina, based on o weight of silica. The composition of claim 10 wherein the silica has a S particle size of 1 to 5 microns.

16. The composition of claim 10 wherein the thixotropic thickener comprises a long chain fatty acid having C 16 a to C 2 carbon atoms in an amount of 0.03 to 0.20%. «a I 20

17. The composition of claim 10 wherein the thixotropic thickener comprises a polyvalent metal salt of a long chain fatty acid having C 16 to C20 carbon atoms in an 1 AIvs are the l~near or branched alkali metal mono- and/or di-(C 8 14 alkyl diphenyl oxide mono and/or disulphates, commercially available for example Q, as DOWFAX (Registered Trademark) 3B-2 and DOWFAX 2A-1. 19 -32- amount of 0.06 to 0.8%.

18. The composition of claim 17 wherein the polyvalent metal is one of aluminium, calcium, zinc and magnesium.

19. The composition of claim 16 additionally comprising a clay thixotropic thickener in an amount of 0.1 to The composition of claim 17 additionally comprising a clay thixotropic thickener in an amount of 0.1 to

21. A method for cleaning soiled glassware and dishware in an automatic dishwashing machine which comprises contacting the soiled dishware in an automatic dishwashing machine in an aqueous washbath having dispersed therein an effective amount of the composition of claim 3.

22. A method for cleaning soiled dishware in an automatic dishwashing machine which comprises contacting the soiled glassware and dishware in an automatic dishwashing machine in an aqueous washbath having dispersed therein an effective amount of the composition of claim DATED this 25 day of March 1991 COLGATE-PALMOLIVE COMPANY Patent Attorneys for the Applicant 0 F.B. RICE CO. 0A G fl iAo ,14V3 4 9