CA1317846C - Thixotropic aqueous liquid automatic dishwashing detergent composition - Google Patents

Abstract

PATENT

IR 4425 and IR 4442(A) THIXOTROPIC AQUEOUS LIQUID AUTOMATIC
DISHWASHING DETERGENT COMPOSITION

ABSTRACT OF THE DISCLOSURE

Thixotropic aqueous liquid automatic dishwashing detergent composition with improved anti-filming properties and method of using the detergent composition. The detergent composition comprises alumina or titanium dioxide anti-filming agent, inorganic builder salts, chlorine bleach, bleach-stable detergent and a thixotropic thickener. The compositions provide reduced filming on dishware, glassware, china and the like, particularly in hard water, and remain stable against phase separation.

Description

IR ~419 and IR ~442(A~
THIXOTROPIC AQUEOUS LIQUID AUTOMATIC
DISHWAS~ING DETERGENT COMPOSITION

FIELD OF THE INVENTION
The present invention r01ates to Q thixotropic aqueous liquid automatic dishwashing detergent composition with improved anti-filming properties and method of using the detergent composition to clean dishware, glassware, china and the like. The dishwashing composition contairls alumina or titanium dioxide, as the anti-filming agent, inorganic builder salts, chlorine bleach, bleach stable detergent ~nd a thixotropic thickener.
The detergent dishwashing composition of the present invention reduce filming on dishware, gla~sware, china and the like, particularly in hard water, and remains stable against phase sepsration.
More speciIically, the invention relates to the use of ~lumina or titanium dioxide as an anti-filming agent in thixotropic aqueous liquid dishw~shing detergent compositions to reduce filming.
The detergent compositions do no require an added rinse aid, are stable in storage, do not settle and are readily redispersible and are pourable.
Th~ present invention also relates to thixotropic aqueous ~uspenæion with improved physical ætability. The invention relates to the use of long chain fatty acids, metal salt~ 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 physical stability properties, which 1re readily dispersible :~

in the washing medium to provide effective cleaning of dishware, glassware, china and the like.
PRIOR ART
Commercially available household-machiine àishwasher detergents S provided in powder form have several disadvantages, e. g. non-uniformcompo~ition; costly operations necessary in their manufacture; tendency to cake in stor~ge at h~gh humidities, resulting in the formation of lumps which are dimcul~ to disperse; dustiness, a source of particular irritation to users who suffer allergies; and tendency to cake in the dishwasher machine dispenser. Liquid form~ of such compositions, however, generally cannot be used in automatic dishwashers due to high ~oam levels, unacceptably low viscosities and exceedingly high alkalinity.
In addition, the pre~ently used formulated powder detergents frequently require a SeparAte Btep of hand towel wiping and drying o~ the dishware, glassw~re, china and the like to avoid leaYing undesirable traces or film Of precipitated calcium and magnesium salts. The use of liquid detergent compclsitions present other pro~lems. The builder salts settle in storage and are not readily redispersed. The compositions al90 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 di3penser cup OI 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 ori~ice, they should quickly lluidize and, upon cessation of the applied shear stress, quickly revert to the high vlscosity/EIingham plastic state . Stability is likewise of prim~ry importAnce, i. e . there should be no signiflcant evidence of phase separation or leaking after long standing.
For effective use, it i8 generally recommended that the automatic dishwa~hing detergent, hereinafter also designated ADD, contain (1) sodium tripolypho3phate (NaTPP) to soften or tie up hard-water minerals und to emulsify and/or peptize soil; (2) sodium sil;cate to supply the alkalinity necessary for effective detergency and to provide protection for fine china glaze snd pattern; ~3) sodium carbonate, generally consldered to be optional, to enhance alkalinity; (4) a chlorine-releasing agent to aid in the elimination of soil specks which lead to water spotting; and (5) defoamer/surfactant to reduce foam, thereby enhancing machine efficiency and ~upplying requisite detergency. See, for example, SDA Detergents in Depth 9 "Pormulations Aspects of machine Dishwashing, " Thomas Oberle (197~. Clean~ers approximating to the afore-described compositions are mostly liquid3 or powder~. Generally, such compositions omit hypochlorite bleach, since it tends to react with other chemically active ingredients, particularly ~urfactant 9 thereby degrading the suspending or thixotropic agent and impairing its effectivenes~.
Thus, U.S. Patent No. 3,985,668 desc~ibes abraqive scouring cleaners of gel-like consistency containing (1) suspending agent, preferably the Smectite and attapulgite types of clay; (2) abraQive, e.g. silica sand or perlite; and (3) fil~er comprising light den~ity powdered polymers, expanded perlite end the like, which has a bouyancy and thus stabilizing effect on the composition in addition to serving a~ a bulking agent, thereby ~5 repla¢ing water o~herwise available for undesired supernatant layer formation due to leaking and phase destabilization. The foregoing are the essential ingredients. Optional ingredients include hypochlorite bleach, bleach stable surfactant and buffer, e. g. silicates, carbonates, and monophosphates. B~ilder~, such as NaTPP, can be included as further optional ingredients to supply or ~upplement building ~unotion not provided 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 components. High pH
is said to minimize decomposition of chlorine bleach and undesired interaction between surfactant and bleach. When pre~ent, NaTPP is limited to 5%, as stated. Foam killer is not disclosed.

B In U.K. Patent Application GB 2,116,199A and GB 2,140,450A, both of which are assigned to Colgate-Pslmolive, liquid ADD compositions are disclosed which have properties desirably charscteri2ing thixotropic, gel-type structure and which include each of the various ingredients necessary for effective detergency with an automatic dlshwasher. The normally gel-like aqueous automatic dishwasher detergent composition having thixotrop~c properties includes the following ingredients, on a weight basig:
(a) 5 to 35% alkali metal tripolypho3phate;
(b) 2,5 to 2096 sodium silicate;
(c) O to 9% al}cali metal carbonate;
(d~ 0.1 to 596 chlorine bleach stable, wster dispersible organic detergent active material;
(e) 0 to 596 chlorine bleach ~table foam depressant;
(f) chlorine bleach compound in an amount to provide about 0. 2 to 4% of available chlorine;
~ g) thixotropic thickener in an amount sufficient to provide the composition with thixotropy index of about 2.5 to 10; and (h) sodium hydroxide, as necessary, to adjust pH.
ADD compositions so formulsted are low-foaming; are readily soluble in the washing medium and most effective at pH values best conducive to impro-red cleaning per~ormance, viz, pH 10.5-13.5. The compositions are normally of gel consistency, i.e. a highly viscous, opaque jelly-like material having Bingham plastlc character and thus relatively high yield values.
Accordingly, a definite shear force i9 necessary to initiate or increase flow, ~ 4 ~ 1 3 ~ 7 8 4 6 62301-1518 such as would obtain within the ayi~ated dispenser cup of an energized automatic dishwasher or a stream o~ water. Under such conditions, the composi~ion is quickly fluidiæed and easily dispensed. 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 ioaming detergent paste for dishwahsers. The composition is based on a mixture o~ finely divided hydrated sodlum 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 copendlng application which is assigned to the common assignee is Canadian patent applicatlon No. 526,708, filed January 6, 1987. This copending application discloses thixotropic aqueous automatic dishwashing detergent composition which contains a long chain ~a~ty acid as a thixotropic thickener agent.
~20~ ADVANTAGES OVER THE PRIOR ART
The thixotropic aqueous liquid detergent compositions of the present invention overcome many of the prior art problems associated with powdex and liquid detergents. Because of the addition of a small effective amount of an alumina or .~
titanium dioxide anti-filming agent to the composition an added ringe aid is not required and towel wiping and drying are not required to obtain dry sparkling clean dishes, glasses, cups and eating utensi1s. The thlxotropic aqueous liquid detergent composition has the additional advantages of being stable, non-settling in storage and readily redispersible. The liquidcompositions of the present lnvention are easily paurable, 1 3 1 7 ~ 4 6 62301-1518 easily measured and ea~ily put into the dishwashing machines.
An additional and unexpected advantage of adding the alumina or titanium dioxide anti-filming agent to the detergent formulation is that the alumina or titanium dioxide inhibit brown stain formation in the dishwashing ~: :
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~ 5a machine. The brown stain is formed by the deposition in the dishwashing machine of iron and/or manganese oxides. The brown stain formation is a particularly serious prohlem in areas having hard water. The alumina or titanium dioxide in the formulation act on ~he iron andfor manganese in the wash water ; to prevent their deposition in the dishwashing machine as iron and~or manganese ox~des.
The present invention seeks to provide a thixotropic aqueous liquid automatic dishwasher detergent composition that has improved anti-filming properties.
The invention also seeks to provide a thixotropic aqueous liquid detergent composition which is stable in ` :
storage, easily pourable and readily dispersible in the dishwashing water.
The invention further seeks to provide a method of ;~ washing dishware, glassware, china and the like in an automatic dishwashing machine using a thixotropic aqueous li~uid detergent composition in which a separate rinse aid is not ::
added or needed.
The lnvention also seeks to provide a method of washing dishware, glassware, china and the like in an automatic washing machine using an aqueous liquid detergent composition by which method the dishware, glassware, china and the like are machine dried without leaving traces or a film.
This invention additionally seeks to provide stable aqueous thixotropic aqueous liquid compositions, especially automatic dishwasher detergent compositions, by incorporating in the aqueous suspension a~small effective amount of an alumina or titanium dioxide anti-filming agent. 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 ~, t ~ 6 623ol-lsl8 settling of the suspended particles and to prevent phase separation.
D~TAILED DESC~IPTION OF THE INVENTION
; The invention, which will become more readily understood from the following detailed desaription of the inventlon and preferred embodiments thereof, is achieved by incorporating in an a~ueous liquid detergent composition a small but effective amount of an alumina or titanium dioxide anti-filming agent. The physical 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, there is provided a normally gel-like automatic dishwasher detergent composition comprising water, at least one ingredient selected from~the group consisting of organic detergent, chlorine bleach, detergent builder, sequestering agents, foam inhibitors and mixtures thereof, from about 0.5 to 5% of an alumina or titanium dioxide anti-filming agent and a :~ s~ufflcient amount of~thixotropic thickener to provide a thixotropic index of about 2.5 to 10. The alumina or titanium dioxide anti-filming agent preferably has a particle size of ~ about O.l to 10 microns. In a preferred embodiment of the ;~ ~ inventlon there is added to the compositl~on a sufficlent amount of~a long chain fatty acid or metal s~alt of a long chain fatty aa~id, or either of the foregoing in admixture with a clay thixotropic thickener to provide a thixotropic index o~ about `

2.5 to 10 and to inhiblt aettling of the suspended particles, such as alkali metal builder salts, etc.
In accordance with this aspect, the present invention provides a normally gel-like aqueous liquid automatic dishwasher detergent composition having thixotropic properties which includes, on a weight basis, ( ~ 3 ~ 7 ~ 4 6 62301-1518 (a) 5 to 35% detergent builder, preferably alkali metal tripolyphosphate;
(b) 2.5 to 40% sodium silicate;
(c) 0.5 to 5% alumina or titanium dioxide anti-filming agent;
(d) 0. to 9~ alkali metal carbonate;
(e) 0.1 to 5% chlorine bleach stable, water dispersible organic detergent active material;
(f) 0 to 5% chlorine bleach stable foam depressant;
(g) chlorine bleach compound in an amount to provide about 0.2 to 4~ o~ available chlorine;

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.
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7a ~ 6~

(h) thixotropic thickener in an amount sufficient to prolride a thixotropic index of about ~.5 to 10.
(i) O to 8~ sodium hydroxide; and (j) balance water.
I Also related to this specific aspect, the in~rention provides a method ¦ for cleaning dishware in an automatic di3hwsshing 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 compo~ition can be readily poured into the ~: 10. dispensing cup of the automntic dishwashing machine and will, within just a few seconds, promptly thick~n to its normal gel-like or pasty state to remain securely within the dispensing cup until shear force~ are again applied thereto, such a~ by the water spray from the dishwashing machine.
Tho invention will now be described in greater detail by way of ~pe~iflc embodiment~ thereof.
The LADD products of for example the prior disclosure in the aforementioned GB 2,116,199A and G8 2,140,450A exhibit rheological properties a8 evsluated by testing product viscosity as a function of shear ~: rate. The compo~itions exhibited higher viscosity at a low shear rate and lower viscosity at a high ~hear rate, the data indicating efficient fluidization and gellation well within the shear rates extant within the standard dishwasher machine. In pr~ctical terms, this means improved : pouring and proce~sing characteristics as we~l as 18ss leaking in the machine di~penser-cup, compared to prior liquid or gel ADD products. For 25 : applied she~r ratec corresponding to 3 to 30 rpm, ~riscosities (Brookfield) correspondingly r~nged from about 10, 000 to 30, OOQ cps to about 3 j 000 to 7,000 cpst a8 measured at room temperatur~ by means of an LVT BrookIield viscometer ~fter 3 minute~ using a No. 4 spindle. A shear rate o~ 7 . 4 sec 1 corresponds to a spindle rpm of about 3. An approximate iO-fold increase in shear rate produces about a 3- to 9-fold reduction in viscosity.

t 3 1 7 ~ ~ ~ 62301-1518 The compositions of the assignee's prior invention thus exhibit threshold fluidizations at lower shear rates and of slgnificantly greater extent in terms of incremental increases in shear rate versus incremental decrease in viscosity. This property of khe LADD products of the prior invention is summarized in terms of a thixotropic index (Tl) which is the ratio of the apparent viscosity at 3 rpm and at 30 rpm. The prior compositions have a Tl of from 2 to 10. The LADD
compositions should exhibit substantial and quick return to prior quiescent state consistency when the shear force is discontinued.
In terms of apparent viscosity, it has been ascertained that so long as the viscosity at room temperature (22~1C) measured in a Brookfield Viscosimeter HATD, using a number 4 spindle at 20 rpm, is less than about 20,000 cps, the composition can be readily shaken so that a thixotropic aomposition can be easily "fluidized" or "liquefied" to allow the product ~o be dispensed through a conventional ~queeze tube bottle or other convenient dispenser.
The present invention is based upon the surprising discovery that substantially improved anti-filming properties can be obtained by adding to the thixotropic aqueous liquid detergent composition a small effective amount of an alumlna or titanium dioxide anti-filming agent. The physical stability, i.e. resistance to phase separation, settllng, etc. can be achieved by adding to the composition a small effective amount of a thixotropic thickener and stabilizing agen~.
ANTI-FILMING AGENTS
The alumina or titanium dioxide anti-filming agent materials that can be used are readily commercially available.
The alumina material that aan be used as an anti-filming agent ~ I

t 3 1 7 8 ~ ~ ~2301-1518 B is insoluble in water and has the formula Al~O3. Suitable materials are available under the ~i~nn~ns-Alumina Oxlde C', Degussa and Catapal D available from Vi~ta Corp. Preferred alumina materlals include fumed alumina ancl a precipitated alum.ina.

9a ,~.

1 3 1 7 ~ 4 6 62301-1518 The tltanlum dloxlde material that can be used as an anti-fllmlng agent ls insoluble ln water and has the formula TiO2. Sultable materials are avallable under the tradenames Tltanlum dloxlde P25, avallable from Degussa Co.
The partlcle size of the alumina and titanlum dioxlde ma~erial that ls used ls important ln achlevlng the deslred antl~fllmlng properties.
The alumlna or tltanlum dloxlde partlcles that are used are flnely divlded and can have a partlcle slze of about 0.10 to 10 ~lcrons, preferably 0.50 to 8 microns and more preferably about 1.0 to 5.0 mlcrons. The alumlna or titanium oxlde partlclea can also have a particle slze of about 0.01 to 8 mlcrons, preferably about 0.02 to 4 or 5 microns. The alumina and titanium dioxide particles of this size and in the amount used he~ein are not abrasive.
The flnely dlvlded alumlna or titanium dioxide material particles ln the dlshwashlng wash act to coagulate protelnaceous particulate ~olls and keeps them ln suspension to prevent them ~rom deposltlng on the clean glass and dlshware.
Without lntending to llmlt the invention in anyway lt is theorized that the alumlna and titanium dloxlde anti-fllming agents ~unctlon in the ~ollowlng manner. The glass surface of vltreous glassware contaln negatlve charges on their surface through the Si-0 bonds. Usually the oxygen atoms carry these charges. It ls postulated that the~e negatlvely charged ions wlll attract posltlvely charged partlcles and thereby wlll form an "artlficlal soll" layer. Thls protectlve layer wlll then repel the regular food soll and wlll lncrease the an~i-redeposltlon property of the automatlc dlshwashlng detergent.
~he alumlna and tltanium dioxide partlcles, respectlvely, will generate posltively charged partlcles whlch will bond 1 31 78~6 62301-1518 themselves to the glassware surface to form the artificial soil layer which will prevent the formation of film.
The amount of alumina or titanium dioxide anti-filming agent that can be used to achieve the desired improvement in film will depend on the hardness of the water, detergent active compound, inorganic salts and other ~DD
ingredients. ~he alumina or titanium dioxide anti-filmil~g agen~

lOa ~317846 i8 particularly effective in hard wash water of, for example, 300 ppm hardness or more.
The amount of alumina or titanium dioxide anti-film agent that is used can be about 0. 5 to 5%, preferably about 1 to 4~ and more preferably about 1.5 to 3% by weight based on the weight of the entire composition.
The alumina and titanium dioxide can eQch be used alone or can be used mix together and/or mix with a silica anti-filming agent. When the anti-filming agent~ or used mixed together the weight percent amounts mentioned ~bove are the total for the irlgredients in the mixture.
THIXOTROPIC_THICKENERS
The thixotropic ~hiclceners or ~uspending agents that can be used in 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 salt~ or inorganic colloid forming clay materials. The thixotropic thickeners should be stable to high alkalinity and ~table to ¦ chlorine bleach compounds such a~ sodium hypochlorite. The preferred thixotl~pic thickeners comprise the fatty acids, the ~tty acid polyvelent metal salt~ a~d the inorganic, cdloid-forming clays of smectite and/or attapulgite types. The amount of the thixotropic thickener used will 2 0 depend on the particular thickener used, but sufficient thickener is added to the formulation to provide the composition with a thixotropy index of about 2.5 to 1û.
The preferred fatty acid thixotropic thickeners are the higher aliphatic fatty monocarboxylic acids having from about 8 to about 22 carbon atoms, more preferabl~ from about 10 to 20 carbon atoms, and especi~lly 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 pre~rred. Mixtures of fatty acid~ may be used, such as those derived from natural sources, such a~ tallow fatty ac}d, coco fatty 1 3 ~ 7 ~ 4 ~ 62301-1518 acid, soya fatty acid, etc., or ~rom synthetic sources available from industrial manufacturing processes.
Thus, examples o~ the fatty aclds which can be used as thickeners includey for example, decanoic acid, lauric acid, dodecanoic acid, palmitic acid, myristic acid, stearic acid, oleic acid, eicosanoic acid~ tallow fatty acldr coco fatty acid, soya ratty acid and mixtures of these ac1ds. Stearic acid and mixed fatty acid, e.g.` coco fatty acld, are preferred.
The amount of the fatty acid thickener to achieve the dAsired values of thixotropy and physical s~ability will depend on such factors as the nature o~ the fatty acid, detergent active compound, inorganic salts, especially TPP, other LADD
ingredients, as well a~ the anticipated storage and shipping conditlons.
Generally, however, amounts of the fatty acid thixotropic agent that can be used are in the range of from about 0.03 to 0.5%, preferably from about 0.03 to 0.2~, especially preferably from about 0.05 to 0.15%, provide the desired long term stability and absence of phase separation.
The polyvalent metal salts of the above fatty acids can also be used in the present invention as thixotroplc thickener agents. Suitable metal salt thixotropic thickeners are disclosed in the Canadian Patent Application No. 546,121 filed September 4, 1987 in the name of Drapier et al.
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 hiyher oxidation states. Naturally, for LADD
compositlons, as well as any other appliaations where the invention composition will or may come in~o contact with 1 ~ 1 7 ~ ~ ~ 623~1-1518 articles u~ed for handling, storage or ser~ing of food products or which otherwise may come into contact with or be consumed by people or animals, the metal sal~ should be selected by taking into consideration the toxicity of the , .

12a 1 31 78~6 metal. For this purpose, the calcium and magnesium salt~ are especially highly preferred as generally safe food additi~ves.
Many of these metal salts are commercially available. For example, the aluminum 9alt9 are available in the trlacid form, e.g. aluminum stearate as aluminum tristearate, Al(C17-E135COO~3. The monoacid salts, e. g. aluminum monostearate, Al(OH}2(C17H35COO) and cliacid salts, e.g. ~uminum distearate, Al(OH~ICl7H35COO)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 ~3, and mixtureR of the mono- and di-acid sslts can be used for those metals, e.g. ~n, with valences of ~2. 1$ is mo~e preferreA that the diacids of the +2 valent metals and the triacids of the +3 valent metals ~ the tetraacids of the +4 metals, and the pentacids of the ~5 valent metals, be used in predominant amounts. For example, at lea~t 30%, preferably at I lea~t 50%, especially preferably from 80 to 100% of the total metal salt should be in the highest po~sible oxidation stste, i.e. each of the possible valence ¦ site~ i8 occupied by a fatty acid residue.
¦ The meta~ ~alts, as mentioned above, are generally commercially available but can be easily produced by, for example, saponification of a fatty acid , e . g. animal fat , stearic acid , etc ., or the corresponding fatty acid e~ter, followed by treatment with an hydroxide or oxide of the polyvalent metal, for example, in the case of the aluminum ~alt, with alum, alumina, etc.
Calcium stearate, i. e . calcium distearate, magnesium stearate, i . e .
magrlesium distearate, aluminum stearste, i . e . aluminum tristearate, and zinc2 5 stearate, i O e . zinc distearate, are the preferred polyvslent fstty acid salt stabilizers. Mixed fatty acid metal salts, such as the naturally occurring acid~, e. g. coco acid, as well as mixed fatty acids resulting from the commercial manufacturing process are also advantageously used as an inexpensi~0 but effectiva source of the long chain fatty acid.

~3 13178~6 The amount of the fatty acid salt sta~ilizers 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 LADD
ingredients, as well as the anticipated storage and shipping condition~.
Generally, however, amount~ of the polyvalent metal fatty acid salt stabilizing agents in the range of from about 0.02 to 1~, preferably from about 0 . 06 to 0 . 8%, especially preferably from about 0 . 08 to 0 . ~%, provide the long term stability and absence of phase separation upon standing or during transporl at both low and elevated temperatures as are required for a commercilally acceptable product.
There may also ba 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 aeid polyvfllent metal salt thickeners. The clay thickeners, however, may be used by them~elve~ as the thixotropic thickeners .
The preferred clay thickeners compri~e the inorganic, colloid forming clays of smectite and/or att~pulgite types.
Smecti~e CIEly8 include montmorillonite (bentonite), hectorite, attapulgite, smectite, saponite, and the like. Montmorillonite clays are preferred and are available under tradenames 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 90, Attagel 50 and Attagel 150 from Engelhard Minerals an~d Chemicals Corporation. Mixtures of smectite and attapulgite types in weight ratios of ~:1 to 1:5 are also useful herein. Thickening or suspending agents of the foregoing types are well known in the art, being described, 13t7~46 for example, in U.S. P&tent No. 3,985,668 referred to above. Abrasives or polishing agents should be avoided in the LADD compositions 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 thickener~ are used in amounts of O .1 to 3%, preferably O .1 to 2 . 5% and more preferably in amounts of O .1 to2~.
When the clsy thixotropic thickeners are used alone as the thixotropic thickener agent they can be used in amounts of about 1.5 to 8~, preferably 2 to 59~ by weight of the formulation.
Generally, LADD effectiveness is directly related to (a) available chlorine levels; (b) alkalinity; (c) solubility in wa~hing medium; and (d) foam inhibition. It i8 preferred herein that the pH of the LADD composition be at least ~bout 9.5, more preferably from about 10.5 to 13.5 and most preferably at least about 11.5. At the relatively lower pH values, the ¦ LADD produot i8 too viscous, i.e. so~id-like, and thus not readily fluidized under the shear-~orce level~ created within the dispenser cup under normal mhchine operating conditions. Addition of NaOH is thu~ often needed to increase the pH to within the above ranges, and to increase flowability properties. The pre~ence of carbonate is ~lso often needed herein, since it acts as a buffer helping to maintain the desired pH level. Excess carbonate is to be ~voided, however, since it m~y cause the formation of needle-like crystals of carbonate, thereby impairing the stability9 thixotropy and/or detergency of the LADD product, as well a~ impairing the di~pensibility of the product from, for example, squeeze tube bottles. Caustic soda ~NaOH) serves the further function of neutralizing the phosphoric or phosphonic acid ester foam depres~ant when present. About 0.5 to 3 wt% of NaOE~ and sbout 2 to 9 wt% of sodium carbonate in the LADD composition sre typical, although it should be noted that sufficient alkalinity may be provided by the NATPP and sodium ~ilicate.

The NaTPP may be employed in the LADD composition in a range of about 8 to 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 hypochlorite 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.
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 of the stable hexahydrate which e~pedites hydration and solubili~ation of 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, therefore, unsuit~ble. Especially preferred LADD compositions are obtained, for example, when using a 0.5:1 to 2:1 weight ratio of anhydrous to hexahydrated NaTPP, value~ of about 1:1 being p~rticularly preferred.
Foam inhibition is importallt to increase dishwasher machine efficiency and minimi~e de tabillizing effects which mi~ht occur due to the presence of . excess foam within the washer during U80. Foam may be sufficiently reduced by ~uitable selection of the type and/or amount of detergent active 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 ~uitable adjustment of the proportions of NaTPP which has a water softenin~ effect may aid in providing the desired degree of foam inhibition.
However, it is generally preferred to include a chlorine bleach stable foam depre~sant or inhibitor. Particularly effective are the alkyl phosphonic acid esters of the formula HO--P--R
OR

1 317~6 available for example from BASF-Wyandotte (PCUK-PAE) 9 and especially the alkyl acid phosphate esters of the formula 1 , HO--P--OR
OR
available, for example~ from Hooker (SAP) ~nd Knapsack (LPKn-158), in :~ ¦ which one Dr both R groups in each type of ester may represent independently a C12_20 alkyl group. Mixtures of the two types, or any other chlorine bleach stable types, or mixtures of mono- and di-esters of the same type, may be employed. Especially preferred is a mixture of I mono- and di-C16 18 ~lkyl acid phosphate esters such ~s 1 monostearyl/distearyl ~cid phosphates 1.211 (Knapsack). When employed, proportions of 0.01 to 5 wt%, preferably 0.1 to 5 wt%, especially about 0.1 to O. 5 wt%, of foam depressant in the composition is typical, the weight ~; ratio of detergent active component (d) to foam depres~ant (e) generally . ranging from about 10:1 to 1:1 ~nd preferably about 4:1 to 1~ Other defoamers which may be use~ include, for exsmple, the known silicones.
Although any chlorine bleach compound may be employ~d in the composit~s of this invention, such a~ dichloro-isocyanurate, dichloro-dimethyl hydantoin, or chlorinated TSP, alk~li metal, e. g.
potassium, lithium, magnesium and especially sodium hypochlo~te is preIerred. The composition should contain sufflcient chlorine bleach compound to provide about O . 2 to 4 . 0% by weight of ava~lable chlorine, as determined, for example, by acidification of 100 parts of the composition with excess of hydrochloric acid . A solution containing ~bout O . 2 to 4 . 096 by weight of sodium hypochlolite contains or provides roughly the same percentage of avail~ble chlorine. A solution containing about 0.8 to 1.6% by weight sodium hypochlorite contains about 0.8 to 1,6% by weig~ht of available chlorine and iq espec~lly preferred. For example, sodiurn hypochlorite 1 31 7~4~

(NaOCl) solution of from about 11 to about 18~ available chlorine in amount~
of about 3 to 20%, preferahly about 7 to 12~, can be advantageously used.
The sodium silicate, which provides alkalinity and protection OI 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 level~ specified herein for example at levels greater than about 10 wt~ the silicate al90 provides increased antispotting action. The sodium silicate i9 generally added in the form OI an aqueous solution, preferably having an Na2O: SiO2 ratio of about 1: 2 . 2 LO 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 here~n must be ~table in the presence of chlorine bleach, e~pecially hypochlorite bleach, and those of the organic anionic, amine oxide, phosphine oxide, sulphoxide or betaine water dispersible surf~ctant type~ are preferred, the first mentioned anionic~
being most preferred. They are used in amounts ranging from about 0.1 to 5% preferably about 0 . 3 to 2 . 0% . Particularly pre~erred surfactants herein are the linear or branched alkali metal mono- and/or di-(C8 14) alkyl diphenyl oxide mono andlor disulphates, commercially available for example as DOWFAX (Regis~ered Trademark) 3B-2 and DOWFAX 2A-1.
In addition, the surfactant should be compatible with the other ingredients of the composition. Other suitable surfactnnts include the primary alkylsulphstes, alkylsulphonates, alkylaryl-sulphonates and sec.-alkylsulphates. Examples include sodium C1~ 18 alkylsulphates such as sodium dodecylsulphate and sodium tallow alcoholsulphate; sodium C10 18 alkanesulphonates such as sodium hexadecyl-l-sulphonate and sodium C12_18 alkylbenzenesulphonates such as sodium dodecylbenzenesulphonates. The corresponding potassium salts may also be employed.

1~

l ~ 31 7~6 As other suitable surfactants or detergents t the amine oxide surfactants are typically of the structure R2R1NO, in which eflch R
represents a lower alkyl group, for instance, methyl, and Rl 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 R2RlPO or sulphoxide RRlSO can be employed. Betaine surfactants are typically of the structure R2RlN -R"COO, in which each R represents a lower alkylene group having from 1 to 5 carbon atom~. Specific examples of these surfactants are lauryl-dimethylamine oxide, myristyldimethylamine oxide, the corresponding phosphine oxides and sulphoxides, and the corre3ponAing betaines, including dodecyldimethylammonium acetate, tetradecyldiethylammonium pentflno~te, hexadecyl-dimethylammonium hexanoate and the like. For biodegradabiliey, the alkyl groups in the3e surfactants should be linear, and such compounds are preferred. .
Surf~ct~nts of the oregoing type, a~l well known in the art, are described, for example, in U.S. Patents 3,985,668 and ~,271,030, The amount o~ water contamed in these composition~ should, of course, be neither 90 high as to produce unduly low viscosity and fluidity, nor so low as to produce unduly high viscosity and low flowability, thixotropic propertie~ in either case being diminished or destroyed. Such amount is readily determined by routine experimentation in any particular instance, gener~ly ranging from about 25 to 75 wt%, preferably about 50 to 65 wt~.
The water should al80 be preferably deionized or soften~d. These amounts 2 5 of water in the composition include the water added a~ parts of the liquid solutlons of other ingredient~, but do no include bound water, for example that in NaTPP hexahydrate.
Other conventional ingredients may be included in these compositions in small amounts, generally less than about 3 wt%, such as perfume, hydrotropic agents such as the sodium ben~Qne, toluene, xylene and cumene 1 ~ 7~46 sulphonate~, preservatives, dye~tuffs and pigments and the like, all of course being stable to chlorine bleach compound and high alkalinity (properti0s of all the components). Especially preferred for coloring are the chlorinated phthalocyanines and polysulphi~es of aluminosilicate which provide, respectively, plea~ing green and blue tint~.
The liquid ADD compositions of this invention are readily employed in known manner for washin~ dishes, glas3ea, cup~, eating utensils and the like in an automatic dishwa~her, provided with a suitable detergent di3penser, in Im aqueou~ wash bath containing an effective amount of the composition .
In a preferred embodiment of the invention the aqueous liquid ¦ dishwashing detergent compo~ition i~ formulated using the below named ¦ ingredients .
Component Wei~ht Percent Alkali Metal Tripolyphosphate 10-25 Sodium Silicste (47.5%) 15-~0 Alumina or Titanium Dioxide Anti-filming Agent 1-4 Alakli Metal Carbonate (anhydrou~) 2-8 Chlorine Bleach Stable, Water Di~persible Organic Detergent Active Material 0.5-3 Chlorine Bleach Stsble Foam Depressant0.10-3 Chlorine BleQch C:ompound 0.2-4 Fatty Acid Thixotropic Thickener 0.03-0.5 Sodium Hydroxide ~ 5096) 2-6 Balance Water ~~~
The thixo~ropic aqueous liquid automaticdishwashing detergent compositions of the present invention can contain conventional dishwashing detergent composition additives. The formulations can be prepared with commercially available solid powder builders, andlor the ingredients can be mixed and the ~ormulations ground to a desired particle size.

1 31 78~6 The invention may be put into praetice in various ways and a number of specific embodiments will be described to illustrnte the invention with - reference to the accompanying examples.
l All amounts and proportions referred to herein are percent by weight ¦ of the compo~ition unles~ otherwise indicated.
The present invention i8 further illustrated by the following examples.
::

1 3 1 7 8 4 6 623~1-1518 ExamPle 1 A thixotropic aqueous liquid automatic dishwashing detergen~ composition is formulated from the following ingredients in the amounts speclfied.
C~P~n~ Weight Percent Deionized Water 39.04 Knapsack LPKN-158 Foam Depressant(l) 0.16 Sodium Hydroxide (50%) 2.3 Sodium Carbonate (anhydrous)4.88 Sodium Tripolyphosphate (anhydrous~ 11.70 Sodiu~ Tripolyphosphate (hexahydrate) 11.70 Alumina Anti-filming Agent(2)2.50 Gel White }1. Clay 1.22 Aluminum Stearate Thixotropic Thickener 0.09 Dowfax 3B-2 Surfactant(3) 0.78 Sodium Hypochlorite (11%) 8.78 Sodium Silicate (1~2.23 - 43.5~) 16.81 Graphtal Green Color 0.002 100.002 (1) Mixture of mono and distearyl (C16-C18) alkyl esters of phosphoric acid, mole ratio 1:1.3.
(2~ Aluminum Oxide Cr (Degussa) has a particle size of about 0.02 microns and is available from Degussa Co.

(3) Na mono- and didecyl diphenyl ether disulfonate (45%
: solu~ion).
The ingredients are mixed following the procedure of the copending commonly assigned Canadian pa~ent application No.
546,121 filed September 4, 1987.
(The ingredlents are added to the water generally in the order listed and gently stirred until a homogeneous mixture is ob~ained.) The ~ormulation is tested by washing glassware and dishware at a temperature of 120E in hard water (300 ppm hardness) in an automatic dishwashing machlne and the clean and dried dishes are found ~o have no apparent fil~.
ExamDle 2 In order to demonstra~e ~he effect of adding the alumlna or tltanium dioxide anti-filming a~ent, formulatlons are prepared wlth and without the alumina and titanium dloxide anti-filming agent and axe compared ~o a commercially available powder detergent composition.
The composltions are ~ormulated to contain the following ingredients.

: .

(A) (B) (C) Tlt~nlum Alumina Dioxlde No Anti-fllmAnti-fllmAnt~-f~lm Component ~ A~ent Agent Deionized Water 39.04 39-04 41,54 Knapsack LPXN 158 Fo~m Depres~arlt 0,16 0.16 0.16 Sodlum ~yd~o~cide (50~) 2.34 2.34 2.34 Sodlum C~rbon~t~ (anhydrous) 4.88 4,88 4.88 Sodlum T ~polyphosphate (anhydroua) 11.70 11.70 11.70 Sodium T ~polyphosph~te (hsxahydrate) 11.70 11.70 11.70 Antl-fllmlng Agent 2.50 2.50 ---Cel Whlte H Clsy 1.22 1.22 1.22 Alum~num Ste~rate Thixotropic Thlckener 0 . 090 . 09 0 . 09 Dowfax 3B-2 Surf~tflnt 0.78 0.78 0.78 8Odlum Hypochlo~te (11~) 8,78 ~.78 8,78 Sodlum Sll~c~te (1/2,~3 - 43,5%) 16.81 16.81 16,81 100.00 100.00 100.00 The ingredients are mixed in a conventlonal manner or can be mixed following the pxocedure of the copending commonly assigned Canadian patent application No. 546rl21 filed September 4, 1987.

tThe in~redients are added to the water generally in the order lis$ed and gently stirred until el homogeneous mixture is obtained.) The formulation is tested by washing glassware at 120F in hard water (300 ppm hardness).

.

23a ,~

1 31 784h The three above formulations (A), (B~ and tC) were te~ted and compared with a commercially available powder automatic dishwa~her detergen~ formulation (D~. The formulRtions were tested in a Kenmore automatilc dishwasher using the procedure describad in ASTMD 3566-79, except that only four cleaning cycles are used. The spotting and filming are evaluated according to the following scales:
Film Rating Scale 1. Be~, no apparent film 2. Filming slight, becoming apparent 3. Noticeable film, lncreasing 4. Continued increAse o~ significant fllm 5. Nlming becoming excessive 6. FYlming high, excessive buil~up 7. Continued increa2e of excessive ~ilm.
Spot Rating Scale A. Be~t - no spot~
B. Very few spo~s app~rent C. Distinct D. Signi~icant coverage appro~nm~tely 50%.
The results obtained are reported in the below Table 1.

I'ormul~t~on Performance R~E
Spot Eilm (A) Alumina Anti-filming Agent B 2-3 (B) Til:anium Dioxide Anti-filming Agent B 2-3 (C) No Anti-filming Agent B 4 (D) Commercial Powder DetergentB-C 3-4 The products (A), (B~ and ~C) left no ~pot on glasswares except one/two prong marks and were rated B. The product (C) with no anti-film additive left a signlflcant uniform film 4 on glasswares. However, 1 31 7~6 ¦ significant fllming improvements were obtained with both alumina and ¦ titanium dioxide.
' I .
Example 3 A thixotropic aqueous liquid automatic dishwashing detergent composition is formulated from the followin~ ingredients in the amounts specified.

Componen~ Weight_ercent Deionlzed Water 32.8 Knapsack LFKN-158 Follm Depressant 0.16 Sodillm Hydroxide ( 50%) 2 . 3 Sodium Carbonate (Anhydrous) 4 . 88 Sodium T:ripolyphosphate (anhydrous) 11. 70 Sodium Tripolyphosphate (hexahydrate) 11.7û

:~ : Alumin~l Anti-film Agent 2.5û

Stearic Acid Thixotropic Thickener 0.10 Dowfax 3B-2 Surfactant 0.60 Sodium Hypochlorlte ~11%) 7.61 Sodium Silicate ( 112 . 4-47 . 5%) 25 . 60 Graphitol Green 0 01 ~ , 100.~0 The ingredients are added to the wuter generally in the order listed and gently stirred until a homogeneou~ mixture is obtained.
The formulation is tested by washing gla~sware at 130F in hard water (300 ppm hardness) in an automatic clishwashing machine. The clean nnd dried glassware are found to have no app~rent film.
The thixo~ropic aqueous liquid automaffc dishwashing detergent compositions of the present invention provide improved film properties.
The lnvention i8 not to be limitad by the above disclosure and Examples 13178~6 which are given as illustrations only. The invention is to be interpreted in :~ccorderou wit the below cl~imf~.

2i

Claims (23)

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 about 0.5 to 5% of an alumina or titanium dioxide or mixture thereof anti-filming agent and a sufficient amount of thixotropic thickener to provide a thixotropic index of about 2.5 to 10.

2. The composition of claim 1 wherein the alumina or titanium dioxide anti-filming is in an amount of about 1 to 4%.

3. A thixotropic aqueous liquid automatic dishwasher composition comprising approximately by weight;
(a) 5 to 35% detergent builder;
(b) 2.5 to 40% sodium silicate;
(c) 0.5 to 5% of an alumina or titanium dioxide anti-filming agent having a particle size of about 0.02 to 8 microns;
(d) 0 to 9% alkali metal carbonate;
(e) 0.1 to 5% chlorine bleach stable, water-dispersible organic detergent active material;
(f) 0 to 5% chlorine bleach stable foam depressant;
(g) chlorine bleach compound in an amount to provide about 0.2 to 5% of available chlorine;
(h) a sufficient amount of a thixotropic thickener to provide a thixotropic index of about 2.5 to 10;
(i) 0 to 8% of sodium hydroxide;
(j) balance water.

4. The composition of claim 3 wherein the thixotropic thickener comprises a long chain fatty acid in an amount of about 0.03 to 0.5%.

5. The composition of claim 3 wherein the thixotropic thickener comprises a polyvalent metal salt of a long chain fatty acid in an amount of about 0.02 to 1.0%.

6. The composition of claim 4 additionally comprising a clay thisotropic thickener in an amount of about 0.1 to 3.0%.

7. The composition of claim 5 additionally comprising a clay thixotropic thickener in an amount of about 0.1 to 3.0%.

8. The composition of claim 3 wherein the alumina or titanium dioxide anti-filming agent has a particle size of about 0.5 to 8.0 microns.

9. A thixotropic aqueous liquid automatic dishwasher composition comprising approximately by weight:
(a) 5 to 35% alkali metal tripolyphosphate;
(b) 2.5 to 40% sodium silicate;
(c) 1 to 4% an alumina or titanium dioxide anti-filming agent having a particle size of about 0.02 of 5.0 microns;
(d) 0 to 9% alkali metal carbonate;
(e) 0.1 to 5% chlorine bleach stable, water dispersible organic detergent active material;
(f) 0 to 5% chlorine bleach stable foam depressant;
(g) chlorine bleach compound in an amount to provide about 0.2 to 4% of available chlorine;

(h) a sufficient amount of a thixotropic thickener to provide a thixotropic index of about 2.5 to 10;
(i) 0 to 8% of sodium hydroxide; and (j) balance water.

10. The composition of claim 8 comprising a non-abrasive amount of said anti-filming agent.

11. The composition of claim 8 wherein the alumina or titanium dioxide anti-filming agent comprises about 1.5 to 3%
by weight of the composition.

12. The composition of claim 8 wherein the alumina anti-filming agent has a particle size of about 1 to 5 microns.

13. The composition of claim 8 wherein the titanium dioxide anti-filming agent has a particle size of about 1 to 5 microns.

14. The composition of claim 8 wherein the alumina anti-filming agent has a particle size of about 0.02 to 4.0 microns.

15. The composition of claim 8 wherein the titanium dioxide anti-filming agent has a particle size of about 0.02 to 4.0 microns.

16. The composition of claim 8 wherein the alumina or titanium oxide anti-filming agent has a particle size of about 0.01 to 0.5 microns.

17. The composition of claim 8 wherein the thixotropic thickener comprises a long chain fatty acid having C10 to C20 carbon atoms in an amount of about 0.03 to 0.20%.

18. The composition of claim 8 wherein the thixotropic thickener comprises a polyvalent metal salt of a long chain fatty acid having C10 to C20 carbon atoms in an amount of about 0.06 to 0.8%.

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

20. The composition of claim 17 additionally comprising a clay thixotropic thickener in an amount of about 0.1 to 2.5%.

21. The composition of claim 18 additionally comprising a clay thixotropic thickener in an amount of about 0.1 to 2.5%.

22. 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 2.

23. 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 8.