CA1322708C - Liquid automatic dishwashing detergent compositions containing bleach-stable nonionic surfactant - Google Patents

Abstract

LIQUID AUTOMATIC DISHWASHING DETERGENT COMPOSITIONS
CONTAINING BLEACH-STABLE NONIONIC SURFACTANT

Abstract of The Disclosure Thickened aqueous automatic dishwashing detergent composi-tions comprising certain bleach-stable capped polyalkylene oxide block copolymer nonionic surfactants.

Description

~322~8 3 ~ 3 ~

BLEACH-STABLE NONIONIC SURFACTANT

fieorge C. Kinstedt Sherri L. Myers Technical Field and Backqround Art This invention relates to aqueous automatic dishwashing detergent compositions which have a yield value and are shear-thinning. Compositions of this general Sype are known.
Examples of such compositions are disclosed in U.S. Patent 4,116,851 to Rupe et al, issued September 26, 1978; U.S. Patent 4,4319559 to Ulrich, issued Feb. 14, 1984; U.S. Patent 4,511,487 to Pruhs et al, issued April 1S, 1985; U.S. Patent 4,512,~08 to Heile, issued April 23, 1985; Canadian Patent 1,031,229, Bush et al;
European Patent Application 0130678, Heile, published Jan. 9, 1985;
European Patent Application 01751~3, Robinson, published April 2, 1986; UK Patent Application 2,116,199A, Julemont et al, published Sept. 21, 1983; UK Patent Application Z,140,450A, Julemont et al, published Nov. 29, 1984; UK Patent Application 2,163,447A, Colarusso, published Feb. 26, 19~B6; and UK Patent Application 2,164,350At Lai et al, published March 19, 1986.
Nonionic surfactants are g2nerally not stable ln the presence of chlorine bleach. Henca, state o~ the art liquid automatic dishwashing detergent compositions gcnerally do not comprise nonionic surfactants. Furthermore, the state of the art liquid automatic dishwashing detergent compositions typically thickened with clay still suffcr from phase separation upon stora~e under certaiR conditions. Phase separation is an even greater problem with nonionic surfactants. Such compositions are improved by the utilization of a polycarboxylate thickener and a phosphate ester stabili7er for improved phasa stability and cohesiveness, as described herein.
The use of polyacrylic thickeners in liquid autom~tic dish-washing detergent compositions is known. See, ~or example, U.K.
Patent Application 2,185,037, Dixit, published July 8, 1987, which 1 3227a~

discloses liquid automatic dishwashing detergents which contain a long chain carboxylic or polycarboxylic acid as the thickener.
Also, European Patent Application 0239379, Brumbaugh, published September 9, 1987, teaches that polyacrylate is useful for water spot reduction in liquid automatic dishwashing detergent composi-tions. U.S. Patent 4,226,736 to Bush et al, issued October 7, 1980, teaches that a polymer of acrylic acid can be used as a thickener in liquid automatic dishwashing detergents instead of clay.
The use of phosphate esters, in gencral, in automatic dishwashing detergent compositions is also known. See, for example~ U.K. Patent Application 2,116,199, Julemont et al, published September 21, 1983, which teaches the use of an alkyl ester of phosphoric acid as a foam depressor.
The combination of polyacrylate thickeners and phosphate ester plus clay has also been taught in U.K. Patent Application 1,164,350, Lai et al, published March 19, 1986. The polyacrylate thickeners taught to be useful have molecular-weights of up to 500,000 ~preferably up to 50,000). These compositions are said to 20 be useful for protection of glazillg on fine china.
It has now been found that certain capped polyalkylene oxide block copolymer nonionic surfacta;nts are relatively stable in the presence of chlor~ne bleach in liquid automatic dishwashing compositions. ~hen such compositions further compr;se the preferred polyacrylate thickener and phosphate ester together in thc absenc~ of clay, bleach stability, enhanced phase stability, improved spotlessness, and reduction of filming are achieved, as well as improved dispensing of the product from its container.

Summarv of ~he Inyention - ~ The ~compositions of this invention are liquid automatic dishwashing deter~ent compositions comprising: -1. hypochlorite bleach to yield available chlorine in an amount of from about 0.1% to about 5%;
2. from about O.lYo to about 5% of a nonionic surfactant having the following structure:
:

~ 3s~2~

(A1)X - (A02)y - R

\ ((A1)x~ - (A2)y~ - R')w wherein I is the residue of a compound selected from the group consisting of a monuhydroxyl compound, a dihydroxyl compound, and a polyhydroxyl compound; AO1 and A02 are oxyalkyl groups and one of AO1 and A02 is propylene oxide with the corresponding x or y being greater than zero, and the other of AO1 and A02 is ethylene oxide with the cor-0 responding x or y being greater than zero, and the molar ratio of propylene oxide to ethylene oxide is from about 2:1 to about 8:1; R and R' are selected from the group cnn-sisting of alkyl aryl, aryl alkyl, alkyl, aryl, cycloalkyl, and mixtures thereof; w is less than 8, preferably equal to zero or one; and x' and y' are greater than:or equal to 2ero.

Detailed Descri~tion of tha Invent~on Bleach-Stable Detergçnt S~f~Ltants The compositions of thls invention contain from about O.l~o to about 5%, preferably from about 0.2% to about 3%, of a bleach-stable capped polyalkylene oxide block copolymer nonionic deter-gent surfactant.
Since the compositions of the present invention contain hypochlorite bleach, the detergent surfactant must be bleach-: 25 stable. Such a surfaetant desirably does not contain functions such as unsaturation and some aromatic, amide, aldehydic, methyl keto or hydroxyl groups which are susceptible to oxidation by the hypochlorite. The capped polyalkylene oxide block copolymer nonionic surfactants prov;de bleach stability. It is believed that the capping function makes the compounds of the present invention less susceptible to oxidation by the hypochlorite.
Bleach-stable nonionic surfactants of th~ prescnt invention are capped polyalkylene oxide block copolymer surfactants of the following structure:

~3227~3 (A01)X - (A~2)y - R

\ ((A1)X~ - (A02)yt - R')w where I is the residue of a monohydroxyl, dihydroxyl, or a polyhydroxyl compound; A01 and A02 are oxyalkyl ~roups and one of A01 and A02 is propylene oxide with the corresponding x or y being greater than zero, and the other of A01 and A02 is ethylene oxide with the corresponding x or y being greater than zero, and the molar ratio of propylene oxide to ethylene oxide is from about 2:1 lo to about 8:1; R and R' are selected from the groups consisting of alkyl, aryl, alkyl aryl, aryl alkyl, cycloalkyl, and mixtures thereof; w is less than 8, preferably equal to zero or one; and x' and y' are greater than or equal to zero.
Preferably the oxyalkyl groups are oxypropyl, oxyethyl, and I5 mixtures thereof; I is the rssidue of an alcohol group, an alkylphenol group, or a dialkyl phenol group, preferably methanol, ethanol, or butanol, or I is the residue of ethylene glycol, propylene glycol, butylene glycol, bisphenol, glycerine, or trimethylolpropane; and R and R' are selected from the group consisting of C1-C~ alkyl, alkyl aryl with an alkyl chain length of C1-Cg, aryl alkyl with an alkyl chain length of C1-Cg, aryl and mixtures thereof. More preferably R and R' are C1-C4 alkyl groups. Most preferably R and fl' are methyl groups. Also preferred in the compounds of ttliS general formula, A01 is propylene oxid~ and A02 is ethylene oxide, and the molar ratio of total propyl~ne oxide to total ethylene oxide is from about 3:1 to about 6:10 Alternative1y, compounds of this general formula in which A02 is propylene oxide and A01 is ethylene oxide, and the mvlar ratio of tot~l propylene oxide to total ethylene oxide is from about 3:1 to about 6:1 are preferred.
Of these compounds, the following structures are preferred:

(1) I - (P0)X - ~EO)y - CH3 ~ (PO~x - (EO)y - CH3 (2) I' `~ (PO)x~ - (EQ)y~ - CH3 ~3~271~

These compounds preferably have molecular weights ranging from about 100~ to about 4000. In these structures I is the residue of a monohydroxyl compound, preferably the residue o~
methanol, ethanol, or butanol, and I' is the r~sidue of a dihydroxyl compound, preferably ethylene glycol, propylene glycol, or butylene glycol. Also, EO is an ethylene oxide group; PO is a propylene oxide group; x and x' are the number of propylene oxide groups; and y and y' are the number of ethylene oxide groups.
Also, x, y, x', and y' are each greater than zero, and the ratio of x to y and x' to y' is from about 3:1 to about 6:1.
The above structures in which the ~EO)y and (PO~X sequencing order are reversed are also useful in the present invention. In these reverse structures, y and y' are the number of propylene oxide groups; x and x' are the number of ethylene oxide groups;
and the ratio of y to x and y' to x' is from about 3:1 to about 6:1.
Most preferably the nonionic surfactant is of the following formula:
~ - ~P)x - (EO)y - CH3 C

- tP)X~ - (EO)y~ - CH3 having a molec~lar weight of about 1800 to about 2000 (preferably l90O~, wherein PO is propylene sxide, EO is ethylene oxide, and the molar ratio of PO to EO is from about 4:1 to abaut 5:1. The surfactant is not only bleach-stable, but it provides low sudsing and superior performance in reducing spotting and filming as well.
Bleachinq Aqent The instant compositions also include a bleaching agent which yields a hypochlorite species in aqueous solution. The hypochlorite ion is chemically represented by the formula OCl-.
The hypochlorite ion is a strong oxidizing agent, and for this reason materials which yield this species are considered to be powerful bleaching agents.

~L3~27~
- li -The strength of an aqueous solution containing hypochlorite ion is measured in terms of available chlorine. This is the ox-idizing power of the solution measured by the ability of the solution to liberate iodine from an acidified iodide solution.
One hypochlorite ion has the oxidizing power of 2 atoms of chlorine, i.e., one molecule of chlorine gas.
At lower pH levels, aqueous solutions formed by dissolving hypochlorite-yieldin~ compounds contain active chlorine?
partially in the form of hypochlorous acid ~oieties and partially in the form of hypochlorite ions. At pH levels above about 10, i.e., at the preferred pH levels of the instant co~positions, essentially all of the acti~e chlorine is in the form of hypochlorite ion.
Those bleaching agents which yield a hypochlnrite species in aqueous solution include alkali metal and alkaline earth metal hypochlorites, hypochlor;te addition products, chloramines, chlorimines, chloramides, and chlorimides. Specific examples of compounds of this type include sodium hypochlorite, potassium hypochlorite, monobasic calcium hypochlorite, dibaslc magnesium hypochlorite, chlorinated trisodium phosphate dodecahydrate, potassium dichloroisocyanurate, ~odium dichloroisocyanurate, sodium dichloroisocyanurate dihydrate, trichlorocyanuric acid, 1,3-dichloro-5,5-dimethylhydantoin, N-chlorosulfamide, Chloramine T, Dichloramine T, Chloramine B and Dichloramine B. A preferred bleachin~ agent for use in the compositions of the instant invention is sodium hypochlorite.
Mos~ of the above-described hypochlorite-yieldin~ bleaching agents are available in solid or concentrated form and are dis-solved in water during preparation of the compositions of the in-; 30 stant i mention. Some of the above materials are availabl~ as aqueous solutions.
The above-described bleaching-agents are dissolved in the aqueous l~quid component of the present composition. Bleaching a~ents can provide from about 0.1% to 5% available chlorine by weight, prefera~ly from about 0.5% to 2.0X available chlorine by weight~ of the total composition.

~2~

Bufferinq Aqent In the instant compositions, it is generally desirable to also include one or more buffering agents capable of maintaining the pH of the instant compositions within the alkaline range.
Preferably the pH range is from about 10.5 to about 12.5. It is in this pH range that optimum performance of the bleach and surfactant are realized, and it is also within this pH range wherein optimum composition chemical stability is achieved.
Maintenance of this particular pH range minimizes the chemical interaction between the strong hypochlorite bleach and the surfactant compounds present in the instant compositions.
Finally, as noted, high pH values such as those maintained by an optional buffering agent serve to enhance the soil and stain removal properties during utili7ation of the present composi~
ti~ns.
Any compatible material or mixture of materials which has the effect of maintaining the composition pH within the alkaline pH range, and preferably within the 10.5 to 12.5 range, can be utilized as the buffering agent in the instant invention. Such materlals can include, for example, various water-soluble, inor-ganic salts such as the carbonates, bicarbonates, sesquicar-bonates, silicates, pyrophosphates, phosphates 9 tetraborates, and mixtures thereof. Examples of materials which can be used either alone or in combination as the bufferlng agent herein include sodium carbonate, sodium bicarbonate, potassium carbonate, sodium sesqu;carbonate, sodium silicate, sodium~ pyrophosphate, tetrapotassium pyrophosphate, tripotassium phosphate~ trisodium phosphate, anhydrous sodium tetraborate, sodium tetraborate pentahydrate, potassium hydroxide, sodium hydroxide, and sodium tetraborate decahydrate. Pr~ferred buffering agents for use herein comprise from about 4% to about 10% sodium sil kate, from about 0.5% to about 1.5% sodium hydroxide, and mixtures thereof.
Buffering agents for use herein may include mix~ures of tetra-potassium pyrophosphate and trisodium phosphate in a pyrophos-phate/phosphate weight ratio of about 3:1, mixtures of tetra-potassium pyrophosphate and tripotassium phosphate in a ~ 3~2~

pyrophosphate/phosphate weight ratio of about 3:1, and mixtures of anhydrous sodium carbonate and sodium silicate in a carbon-ate/silicate weight ratio of about 1:3 to about 3:1, preferably from about 1:2 to about 2:1.
If present, the above-described buffering agent materials are dissolved or suspended ;n the aqueous l;quid component.
Buffering agents can generally comprise from about 2% to 20Yo by weight, preferably from about 5% to 15% by weight, af the total composition.
DeterqencY Builder Detergency builders are desir~ble materials which reduce the free calo;um and/or magnesium ion concentration in a surfactant-containing aqueous solution. They are used hsrein at a level of from about 5% to about 40YO, preferably from about 15% to about 30%. The preferred detergency builder for use herein is sodium tripolyphosphate in an amount from about 10% to about 40X, preferably from about 20% to about 30%. Generally a certain percentage of the sod;um tripolyphosphate is ;n an undissolved particulate form suspended in the rest of the detergent com-position.
Other detergency builders include potassium pyrophosphate, sodium pyrophosphate, potassium tripolyphosphate, potassium hexametaphosphate, and alkal; metal carbonates suoh as sodium carbonate.
Some ~f the above-described buffering a~ent materials additionally serve as builders. It is preferred that the buffering agent conta~n at least one compound capable of additionally acting as a builder.
PolYcarboxylate PolYmer The compositions of the present ;nvention preferably com-pr;se a high molecular weight polycarboxylate polymer thickener.
By i'high molecular weight" is meant from about 500,000 to about 3~ 5,000,000, preferably from about 750,000 to about 4,000,000.

~3227~

g The polycarboxylate polymer may be a carboxyvinyl polymer.
Such compounds are disclosed in U.S. Patent 2,798,053, issued on July 2, 1957, to Brown.
Methods for making carboxyvinyl polymers are also disclosed in Brown.
A carboxyvinyl polymer is an interpolymer of a monomeric mixture comprising a monomeric olefinically unsaturated carboxylic acid, and from about 0.1% to about 10% by weight of the total monomers of a polyether of a polyhydric alcohol, ~hich polyhydric alcohol contains at least four carbon atoms to which are attached at least three hydroxyl groups, the polyether containing more than one alkenyl group per molecule. Other monoolefinic monomeric materials may be present in the monomeric mixture if desired, even in predominant proportion. Carboxyvinyl polymers are substantially insoluble in liquid, volatile organic hydrocarbons and are dimensionally stable on exposure to air.
Preferred polyhydric alcohols used to produce carboxyvinyl polymers include polyols selected from the class consisting of oligosaccarides, reduced derivatives thereof in which the carbonyl group is converted to an alcohol group, and pentaerythritol; more preferred are oligosaccharides, most preferred is sucrose. It is preferred that the hydroxyl groups of the polyol which are modified be etherified with allyl groups, the polyol having at least two allyl ether groups per polyol molecule. ~hen the polyol is sucrose, it is preferred that the sucrose have at least about five allyl ether groups per sucrose molecule. It is preferred that the polyether of the polyol comprise from about 0.1% to about 4% of the total monomers, more preferably from a~out 0.2~o to about 2.5%.
Preferred monomeric olefinically unsaturated carboxylic acids for use in producing carboxyvinyl polymers used herein include monomeric, polymerizable, alpha-beta monoolefinically unsaturated lower aliphatic carb~xylic acids; more preferred are monomeric monoolefinic acrylic acids of the structure CH2 = G - COOH

~22~

where R is a substituent selected from the group consisting of hydrogen and lower alkyl groups; most preferred is acrylic acid.
Carboxyvinyl polymers useful in formulations of the present invention have a molecular weight of at least about 750,000;
preferred are highly cross-linked carboxyvinyl polymers having a molecular weight of at least about 1~250,000; also preferred are carboxyvinyl polymers having a molecular weight of at least about 3,000,000 which may be less highly cross-linked.
Various carboxyvinyl polymers are commercially available from B. F. Goodrich Company, New York, N~Yo~ under the trade mark Carbopol. Carboxyvinyl polymers useful in formulations of the present invention include Carbopol 910 having a molecular weight of about 750,000, preferred Garbopol 941 having a molecular weight of about 1,250,000, and more preferred Carbopols 934 and 940 having molecular weights of about 3,000,000 and 4,000,0CO9 respectively.
Carbopol 934 is a very slightly cross-linked carboxyvinyl polymer having a molecular weight of about 3,000,000. It has been described as a high molecular weight polyacrylic acid cross-linked with about 1% of polyallyl sucrose having an average of about 5.8 allyl groups for each molecule of sucrose.
Additional polycarboxylate polymers useful in the present invention are Sokalan PHC-25R, a polyacrylic acid available from BASF Corp. and GantrezR, a poly (methyl vinyl ether/maelic acid) interpolymer available from GAF.
Preferred polycarboxylate polymers of the present invention are non-linear, water-dispersible polyacrylic acid cross-linked with a polyalkenyl pclyether and having a molecular weight of from about 750,000 to abo~t 4,000,000. Highly preferred examples of these polycarboxylate polymer thickeners for use in the present invention are the Carbopol S00 s~ries resins available from B~ F. Gondrich. Especially preferred are Carbopol 616 and 617~ It is believed that these resins are more highly cross-linked than the 900 seri@s resins and ha~e molecular 3s weights between 1,000,000 and 4,000,000~

~ ~., ~3227~8 Mixtures of polycarboxylate polymers as herein described may also be used in the present invention. Particular1y preferred is a mixture of Carbopol 616 and 617 series resins.
The nonionic surfactant and polycarboxylate polymer S thickener of the present invention are preferably utilized with essentially no clay thickening agents. In fact, it has bqen found that if the nonionic surfactant and polycarboxylate polymer of the present invention are utilized with clay in the composition o~ the present invention, a much less desirable product results in terms of phase instability. A trace amount of clay may be acceptable, preferably less than 0.05~O clay. The polycarboxylate polymer is preferably used instead of clay as a thickening/stabilizing agent in the present compositions.
The polycarboxylate polymer also provides a reduction in what is commonly called "bottle hang-upn. This term refers to the inability to dispense all of the dishwashing detergent product from its container. ~ithout wishing to be bound by theory, it is believed that the compositions of the present invention provide this benefit because the force of cohesion of the compositlon ~s greater than the force of adhesion to the container wall. With clay thickener systems, which most commercially available products contain, bottle hang-up can be a significant problem under certain conditions.
Without wishing to be bound by theory, it is also believed that the long chain molecules of the polysarboxylate polymer thickener help to suspend solids in the detergent rompositions of the present invention and help to keep th~ matrix expanded. The polymeric material is also less sensitive than clay th kkeners to destruction due to repeated shearing, such as occurs when the composition is vigorously mixed.
From about 0.1% to about 10%, preferably from about 0.2% ~o about 2%, of the high mole~ular weight polycarboxylate polymer is used in the composition of the present invention.
The polymeric thicken~r is utilized to provide a yield value of from about 50 to about 350, and most preferably from about 75 to about 300.

~3227~

Yield Value Analysis The yield value is an indication of the shear stress at which the gel strength is exceeded and flow is initiated. It is measured herein with a Brookfield RVT model viscometer with a T-bar B spindle at 25C utilizing a Helipath drive upward durin~
associated readings. The system is set to O.S RPM and a reading is taken for the composition to be tested after 30 seconds or after the system is stable. The system is stopped and the RPM is reset to 1.0 RPM. A reading is taken for the same composition after 30 seconds or after the system is stable. Stress at zero shear is equal to two times the 0.5 RPM reading minus the reading at 1.0 RPM. The yield value i~ calculated as the stress at zero shear times 18.8 (conversion factor).

Phosphate Ester The compositions of the present invent~on may also comprise an ester of phosphoric acid (phosphate ester) for enhanced stability. Phosphate esters are any materials-of the general formula:
0 ~o RO - P - OH and HO - P - OH
OR' OR' wherein R and R' are C6-C20 alkyl or ethoxylated alky~ groups of the g neral formula: alkyl-(OCHyCH2)y wherein the alkyl 2$ substituent is C6-C?o and Y is between O and about 4. Most preferably the alkyl substituent of that formula is C12-Clg and y is between about 2 and about 4. Such compounds are prepared by known methods from phosphorus pentoxids, phosphor k acid, or phosphorus oxy halide and alcohols or ethoxylated alcohols.
It ~ill be appreciated that the formula depicted represent mono- and di-esters, and commercial phosphate esters will generally comprise mixtures of the mono- and di-esters9 togethe~
with some proportion of tri-ester. Typical commercial esters are available under th~ trademarks "Phospholan~ PDB3 (D~amond Shamrock), "Servoxyl" VPAJ (Servo), PCUK-PAE (BASF-Wyandotte), and SAPC (Hooker). Preferred for use in the prèsent invention are KW340N and KL340N (Hoescht) and monostearyl acid phosphate (Oxidental Chemical Corp.). Most preferred for use in the present invention is Hostophat-TP-2253 (Hoescht).
The phosphate ester component aids in control of specific gravity of the detergent products of the present invention. The phosphate ester also helps to maintain stability of the product.
The phosphate esters useful herein also provide protection of silver and silver-plated utensil surfaces. The phosphate ester component also acts as a suds suppressor; thus an additional suds suppressor is not required in the surfactant-containing detergent compositions disclosed herein.
These phosphate esters in combination with the polycarboxy-late polymer thickener provide enhanced stability to the liquid automatic dishwashing detergent compositions af the present invention. More specifically, the phosphate ester component helps to keep the solid particles in the compositions of the present invention in suspension. Thus, the combination inhibits the separation out oF a liquid layer from compositions of this type.
From about 0.1% to about 5%, preferably from about 0.15% to about 1.0% of the phosphate ester component may be used in the compositions of the present invention.

Entrained Gas ~5 Optionally, the composition-s of the present invention may comprise entrained gas to further ensure stability.
Th~ entrained gas can be any gaseous material that is insoluble in the aqueous liquid. Air is preferred, but any gas that will not react with the composition, such as nitrogen, is also useful.
The entrained gas bubbles are preferably in very finely divided form, preferably less than about 1/32 in. in diam~ter.
They are dispersed throughout th~ aqueous liquid in an amount, - generally from about 1% to about 20Yo~ preferably from about 5% to about 15% by volume, to lower the specific gravity of the overall compositlon to withln from about 5% more than to about lOZo less ~227~

than, preferably within from about 1% more than to about S~O less than the spec;fic gravity of the aqueous liquid without the entrained gas. It is more desirable to be below the specific gravity of the aqueous phase. Any phase separation is then at the bottom of the container, and pouring will tend to remix the separated phase before it is dispensed.
The gas can be admixed with high shear mixing> e.g., through a shear device that has close tolerances to achieve air bubble size reduction. High shear mixing ~an be attained with shear rates greater than about 1000 sec^1, preferably greater than about 15,000 sec~1, most preferably greater than 30,000 sec~1.
The polycarboxylate polymer, on the other hand, should preferably be added last to minimize excessive exposure to shear. Each of these preferred processing steps gives compositions with superior stability. The gas can also be introduced in finely divided form by using a sparger.

Hvdroxy ~FattY Acid Salt Because automatic d~shwashing detergent compositions contain bleach, sterling or silver-plated flatware can become tarnished after repeated exposures to the harsh composition. Metal salts of long chain hydroxy fatty acids llave been found to be useful in automatic dishwashing detergent compositions of this type-to inhibit said tarnishing. By "long chain hydroxy fatty acid" is meant the higher aliphatic hydroxy fatty acids having from about 8 to about 22 carbon atoms, preferably from about 10 to 20 carbon atoms, and most preferably from about 12 to 18 carbon atoms, incluslve of the carbor atom of carboxyl gro~lp of the fatty acid.
Hydroxy stearic acid is especially preferred. By ~'mctal salts"
of the long chain hydroxy fatty acids is meant both monoYalent and polyvalent metal salts particularly the sodium, potassium, lithium, aluminum and zinc salts. Particularly preferred is the lithium salts of the hydroxy fatty acids. Specific examples of the preferred materials are potassium, sodium and particularly lithium hydroxy stearate. The compounds are compatable with bleach and other components traditionally found~in automatic ~3~2~

dishwashing detergent compositions. These compounds are essentially insoluble in water. Because of the presence of the hydroxy group in these compounds, they do not significantly affect viscosity of the compositions of the present invention.
Thus, the hydroxy fatty acid salts are useful in connection with thickening agents such as clay or polycarboxylate th k k2n2rs in automatic dishwashing detergent compositions. The metals salts of long chain hydroxy fatty acids may optionally be incorporated into the automatic dishwashing detergent compositions of the lo present invention at from about 0.05% to about 0.3%, preferahly from about 0.05% to about 0.2X, by weight of the detergent composition.

Other Optional Materials Conventional coloring agents and perfumes can also be added to the instant compositions ta enhance their aesthet~c appeal andJor consumer acceptability. These materials should, of course, be those dye and perfume varieties which are especially stable against degradation by high pH and/or strong active chlorine bleaching agents.
If present, the above-described other optional materials generally comprise no more than about 10% by weight of the total composition and are dissolved, suspended, or emulsified in the present compositions.

~1 Preferred compositions of this invention are liquid automatic dishwasher detergent compositions comprising:
(1) from about 15% to about 25Yo of sodium tripolyphosphate;
(2) from about 4% to about lOYo of sodium silicate;
(3) from about 3X to about 10Z of sodium carbonate;

(4) hypochlori~e bleach in an amount to provide from about 0.5YO to about 1.5~ of available chlorine;

(5) ~rom about 0.2% to about 2~ of a polycarboxylate polymer thickening agent selected from the ~roup consisting of polycarbo~ylate polymers comprising non-linear, ~3~7~

water-dispersible polyacrylic acid cross-linked with polyalkenyl polyether having a molecular weight of from about 750,000 to about 4,000,000, and mixtures thereof;
~6) from about 0.15~ to about 1% of an ethoxylated alkyl ester of phosphoric acid having an average alkyl chain length of from about 12 to about 18 oarbon atoms and an average number of ethoxylate units of from about 2 to about 4; and (7) from about 0.5X to about 2% of a nonionic surfactant haYing the following structure:
/ O-(P0)x-(EO)y-CH~
C

O~(PO)x'~(EO)y~-CH3 and having a molecular w~ight of about 1900, wherein P0 is propylene oxide, E0 ts ethylene oxide, and the molar ratio of P0 to E0 is from about 4:1 to about 5:1; said liquid detergent composition containing no clay suspension agents and having a yield value of l`rom about 100 to about 250.
Th~ following examples illustrate the present invention. It will be appreciated that other motiificatlons of the present inven-tion, within the skill of those in the automatlc liquid dishwashing d~tergency art, can be undertaken without departing from the spirit and scope of this invention.
All parts, percentages, and ratios herein are by weight unless otherw~se spectfled.

; EXAMPLE I
Preparation of a compound of the following formula:
/0 - (P)X - (E~)y - CH3 .

- (PO)x~ - (EO)yJ - CH3 ~322~a8 having a moleoular weight of about 1900, wherein PO is propylene oxide, EO is ethylene oxide, and the molar ratio of PO to EO is from about 4:1 to about 5:1, is as follows.
The initi~tor, ethylene glycol, is reacted first with propylene oxide and then with ethylene oxide und~r base catalysis with KOH to form the potassium salt of the polyol.
This is then reacted with either dimethyl sulfate in the presence of sodium hydroxide or with methyl ehloride and CH30Na or CH30K to yield the methyl capped polyalkylene o oxide block copolymer nonionic surfactant. this nonionic surfactant is significantly ~ore stable in the presence of chlorine bleach than the uncapped parent molecule.
Other nonionic surfactants of th~ present invention can be prepared in a similar fashion EXAMPlE II
A liquid automatic dishwashing deter~ent compnsition of the invention is as follows:
Component Wt. %
Sodium tripolyphosphate (anhydrous basis) 20.0 Capped polyalkylene oxide block copolymer nonion~c surfactant of Examp!e I 1.0 Sodium carbonate 6.0 Sodium hydroxide 0.95 AYailable chlorine from sodium hypochlorlte 1.0 Sod1u~ silicate solids (2.4R) 6.54 :~ Polyacrylate thickener-Carbopol 616 0.~0 : Polyacrylate thickener-Carbopol 617 0.25 Ethoxylated phosphate ester-Hostophat TP-2253 0.20 Lithium hydroxystearate 1.0 Minor ingredients and water Balance The omposition~is prepared as follows. The NaOCl, NaOH, sodium silicate, perfume, lithium hydroxystearate, phosphate ester, and water are combined in a stainless steel container which is placed in an ice bath. A Ross mixer is used to high shear mix the contents of th conta~ner whils add~ng the sodium tripolyphosphate and the sodium carbonate. M~xing is continued ~3227~

ulltil the particle size is acceptably small, i.e., no visible clumps of sodium tripolyphosphate or sodium carbonate particles can be seen in a thin film of the mixture on a stainless steel spatula. Mixing is continued as the nonionic surfactant is added. Mixing is then stopped and the container is removed from the ice bath. A paddle mixer is th2n placed into the mixture. The dye is then paddled into the mixture. In a separate container the polycarboxylate polymer is premixed with enough water to moisten the polymer. The polymer slurry (2.5%3 is then paddled into the mixture of the other components.
The resulting automatic dishwashing detergent composition has a pH (1% solution) of about 11, a yield value of about 150, and a specific gravity of about 1.32. Th;s detergent composition has bleach stability and enhanced phase stability when compared with similar products thickened with clay or other colloid thickeners. This enhanced phase stability can be seen when the composition of the present invention is stored at 25C for four months; no separation out of a liquid phase results. This is comparable to at least 1% separat.ion out of a liquid phase for traditional clay-thickened autoMatic dishwashing detergent compositions in a much shorter period of time. This detergent also provides superior spotlessness and reduction of filming on dishware and reduced bottle hang-up.
Other compositions of the present ~nvention are obtained when the nonionio surfactant of Example I is replaced with other - polyalkylene oxide block copolymer nonionic surfactants havingmolecular weights between 1000 and 4003 and comprising propylene oxid~ and ethylene oxide in a molar ratio of from about 4:1 to about 5:1, and being capped with a capping group selected from C1-Cg alkyl, alkyl aryl with an alkyl chain length of C1-Cg, aryl alkyl with an alkyl chain length of C1-Cg, aryl, and mi~tures thereof.
Yet other compositions of the present invention are obtained when the Carbopol polyacrylate thickeners are replaoed in whole 3s or in part with polyacrylate polymers sold under the trade names ~3227~8 Sokolan PHC-25R, available from BASF Corp., or 6antrezR, available from GAF Corp.

WHAT IS CLAIMED IS:

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Claims (21)

1. A liquid automatic dishwashing detergent composition comprising:
(a) hypochlorite bleach to yield available chlorine in an amount of from about 0.1% to about 5%; and (b) from about 0.1% to about 5% of a nonionic surfactant having the following structure:
wherein I is the residue of a compound selected from the group consisting of a monohydroxyl compound, a dihydroxyl compound, and a polyhydroxyl compound; AOl and AO2 are oxyalkyl groups and one of AOl and AO2 is propylene oxide with the corresponding x or y being greater than zero, and the other of AO1 and AO2 is ethylene oxide with the cor-responding x or y being greater than zero, and the molar ratio of propylene oxide to ethylene oxide is from about 2:1 to about 8:1; R and R' are selected from the group con-sisting of alkyl aryl, aryl alkyl, alkyl, aryl, cycloalkyl, and mixtures thereof; w is less than 8, preferably equal to zero or one; and x' and y' are greater than or equal to zero.

2. The composition of Claim 1 wherein I is the residue of a monohydroxyl compound selected from the group consisting of branched and unbranched alcohol groups, an alkyl phenol group, or a dialkyl phenol group.

3. The composition of Claim 1 wherein I is the residue of a monohydroxyl compound selected from the group consisting of methanol, ethanol, and butanol; the residue of a dihydroxyl compound selected from the group consisting of ethylene glycol, propylene glycol, butylene glycol, and bisphenol; or the residue of the polyhydroxyl compound selected from the group consisting of glycerine and trimethylolpropane.

4. The composition of Claim 1 wherein R and R' are selected from the group consisting of C1-C8 alkyl, alkyl aryl with an alkyl chain length of C1-C8, aryl alkyl with an alkyl chain length of C1-C8, aryl, and mixtures thereof.

5. The composition of Claim 4 wherein R and R' are methyl groups.

6. The composition of Claim 4 wherein AO1 is propylene oxide, AO2 is ethylene oxide, and the molar ratio of total propylene oxide to total ethylene oxide is from about 3:1 to about 6:1.

7. The composition of Claim 6 wherein w is equal to zero and R
is a methyl group.

8. The composition of Claim 6 wherein w is equal to one and R
and R' are methyl groups.

9. The composition of Claim 4 wherein AO2 is propylene oxide, AO1 is ethylene oxide, and the molar ratio of total propylene oxide to total ethylene oxide is, from about 3:1 to about 6:1.

10. The composition of Claim 9 wherein w is equal to zero and R
is a methyl group.

11. The composition of Claim 9 wherein w is equal to one and R
and R' are methyl groups.

12. The composition of Claim 1 wherein the surfactant is:

having a molecular weight of about 1900, wherein PO is propylene oxide and EO is ethylene oxide and the molar ratio of PO to EO is from about 4:1 to about 5:1, and mixtures thereof.

13. The composition of Claim 1 which additionally comprises from about 5% to about 40% of detergency builder.

14. The composition of Claim 13 wherein said detergency builder is selected from the group consisting of sodium tripolyphosphate, sodium carbonate, potassium pyrophosphate, sodium pyrophosphate, and mixtures thereof.

15. The composition of Claim 14 which additionally comprises from about 4% to about 10% of sodium silicate.

16. The composition of Claim 15 which additionally comprises from about 0.5% to about 1.5% of sodium hydroxide.

17; The composition of claim 14 comprising sodium hypochlorite to yield from about 0.5% to about 2% of available chlorine.

18. The composition of Claim 14 additionally comprising a polycarboxylate polymer thickening agent having a molecular weight of from about 500,000 to about 5,000,000; and mixtures thereof.

19. The composition of Claim 18 wherein said polycarboxylate polymer thickening agent is selected from the group consisting of polycarboxylate polymers comprising non-linear, water-dispersi-ble, polyacrylic acid cross-linked with a polyalkenyl polyether having a molecular weight between about 750,000 and about 4,000,000; and mixtures thereof.

20. A liquid automatic dishwashing detergent composition comprising:
(a) from about 15% to about 255 of sodium tripolyphosphate, (b) from about 4% to about 10% of sodium silicate, (c) from about 3% to about 10% of sodim carbonate;
(d) hypochlorite bleach in an amount to provide from about 0.5% to about 1.5% of available chlorine;

(e) from about 0.2% to about 2% of a polycarboxylate polymer thickening agent selected from the group consisting of polycarboxylate polymers comprising non-linear, water-dispersible, polyacrylic acid cross-linked with a polyalkenyl polyether having a molecular weight of from about 750,000 to about 4,000,000, and mixtures thereof;
(f) from about 0.5% to about 2%. of a nonionic surfactant of the following structure:

having a molecular weight of about 1900, wherein PO is propylene oxide, EO is ethylene oxide, and the molar ratio of PO to EO is from about 4:1 to about 5:1.

21. The composition of Claim 20 containing no clay suspension agents and having a yield value of from about 100 to about 250.