CA2093783A1 - Pretreatment compositions for dishware - Google Patents

Abstract

Abstract of Disclosure The present invention relates to a pretreatment composition for dishware which comprises a thickening agent; a calcium compound; a preservative; a buffer system; at least one detergent active material; at least one stabilizer; at least one enzyme, an alkali metal nitrate; and water, wherein the composition at a concentration of 10 grams of said composition in one liter of an aqueous bath has a pH of about 6 to about 12.

Description

2~93783 Field of the Invention The present invention relates to a pretreatment composition for dishware which comprises: a thickening agent;
a calcium compound; a preservative; a buffer system; at least one detergent active material; at least one stabilizer; at least one enzyme; an alkali metal nitrate; and water, wherein the composition has a pH of about 6 to about 12.

Background of the Invention This invention relates to compositions in the form of liquids, sprays, gel~, and pastes, which remove dried-on and cooked-on food and other difficult-to-remove soils from kitchen utensils, flatware, dishes, glassware, cookware, bakeware, cooking surfaces, and surrounding areAs in a convenient, easy, timely, and mild manner.
Of the difficult-to-remove soils, the most severe is the baked and/or burned-on (especially when reheated and/or allowed to build up over time). These are very difficult to remove, without using severe methods including heat and alkali. But there is another category of soils that is also a problem especially in automatic dishwashing. Soil categories include grease, meat (including skin), dairy, fruit pie filling, carbohydrate, and starch. Soiled substrate categories include aluminum, iron, stainless steel, enamel, plastic, Corningware, Pyrex, and other glass cookware.

21~937~3 When people ~ ~h dishes by hand, these d ~icult 90ils are individually treated using assorted household detergents, especially light duty liquids, and lots o~ mechanical action.
When people use a dishwasher, these tough soils require extensive pretreatment, almost to the point of completely washing the dish before putting it in the dishwasher.
Pretreatment i9 required because of the mechanical deficiencies of the dishwashers and because people dislike having to rewash dishes because they did not come clean the first time. The use of light duty liquids for the purpose of pretreatment is inconvenient because the surfactants are very foamy and highly unsuitable for use in an automatic dishwasher. They must be rinsed off completely before putting the items in the dishwasher. It i9 possible to use automatic dishwasher detergent for pretreating items to be washed by a mechanical dishwasher. Deficiencies of this method revolve around the caustic and highly oxidizing nature of conventional autodish detergents which usually contain hypochlorite bleach releasing agents and alkali. Thus autodish detergents, whether dissolved or in a slurry form, are dangerous, caustic, attack surfaces and release fumes.
People use all sorts of tools and substances to pretreat their dishes. Examples include sponges, brushes, towels, steel wool, nonwoven plastic or fiber scrubber pads, copper mesh scrub pads, plastic mesh scrub pads and the like. They also use various substances including light duty liquid dish detergent (such as Dawn, Palmolive, A~ax, Lux, or Joy), ammonia, bleach, table salt, washing soda, baking soda, and 2~37~3 commercial hard s~ ~ace cleaners (for example Fantastic, Ajax, or 409). The physical methods are a lot of work. The light duty liquid detergents are formulated to have high foam levels. They require complete and careful rinsing before putting any item washed with them into the dishwasher.
Ammonia and bleach can be corrosive and dangerous to people and to the household items and surfaces. Table salt, washing soda and baking soda by themselves are not effective on many types of tough soil.
It is possible to use a specially formulated pretreatment composition based on surfactants, polyhydric alcohols and a thickener such as described in US Pat. No. 4,818,427. This material does not take advantage of the catalytic power of enzymes and requires a relatively long soaking time, preferably at least 30 minutes.

Summa~y~e~4~ n The present invention relates to a pretreatment composition for dishware which comprises approximately by weight: 0.01 to 5.0~ of a thickening agent; 0 to 1.0~ of a calcium compound; .001 to 1.0~ of a preservative; 0.1 to 5~ by dry weight of a buffer system; 0 to 7.0% of at least one detergent active material; 0 to 8.0~ of at least one stabilizer; 0.1 to 5.0~ of a mixture of one or more enzymes; 0 to 5~ of an alkali metal nitrate; and the balance being water, wherein the composition at a concentration of 10 grams of said composition in one liter of an aqueous bath has a pH of about 6 to about 12.

7 ~ 3 An objective ~ the invention is to redu the work of pretreating dishes before putting them in an automatic dishwasher by eliminating the complex routines of rinsing, scraping and sorting typically undergone by the North American consumer.
Another objective is a composition to reduce the need to rewash items that have been through the dishwasher cycle but that are still dirty because they were soiled with tough soils such as starch, grease, egg, milk and cheese.
A further objective is a composition to increase the types of items that go into the dishwasher. Often pots, pans and casseroles are washed by hand because they tend not to be well cleaned in the dishwasher.
It is an object of this invention to remove the labor of doing these by hand and enable them to be put into the machine and come out clean.
Another object of this invention is to use the waiting time between the time that the dishwasher i9 loaded and the time the machine is turned on in such a way as to aid in the cleaning of the dishes. Often only a few dishes are loaded into the dishwasher after each meal. Then the dishes ~it, sometimes for hours and days, gradually drying out and getting harder to clean. With this invention, the dishes get easier to clean as they sit.
General Description The pretreatment compositions, used to pretreat dishware for soil removal prior to cleaning the dishware in an automatic dishwasher, comprise a mixture of water, a 2q~3~3 thickening agent, - least one enzyme, a buff system, a calcium compound, a stabilizer, a preservative, an alkali metal nitrate, and optionally: at least one detergent active material, a colorant, a fragrance, an alcohol, optionally, a polyhydric alcohol, and an anti-foam agent.
The thickening agents which are employed in the instant compositions at a concentration of about 0.01 to about 5.0 wt.
%, more preferably 0.025 to about 2.0 wt. % and most preferably about 0.05 to about 1.5 wt. ~ are used to adjust the Brookfield viscosity of the composition to about 20 to about 1,000 Cp9, more preferably about 100 to 600 cps and most preferably about 140 to 550 cps [as measured at 10 rpm in a Brookfield DV II, #1 spindle] 90 that the compositions do not run off, but rather adhere to plates stacked in a non-horizontal alignment, preferably a vertical alignment. Usefulthickening agents are selected from the group consisting of xanthan gum, welan gum, rhamsan gum, carboxymethyl cellulose, hydroxyalkyl cellulose, (hydroxyethyl cellusose), alkyl cellulose, polyethylene glycol, polyalkylene oxide, polyvinyl alcohol, guar gum, locust bean gum, and polysaccharides with beta glycoside linkages and mixtures thereof. Maleic anhydride polymers, maleic anhydride-methyl vinyl ether co-polymers and polyacrylic acid thickeners are also useful.
Less suitable thickeners are inorganic colloidal materials (clays) including magnesium aluminum silicates. In the presence of Ca ion it is preferred to have a non-chelating thickener.

2~3783 The compositi ~s include about 0 to abou 1.0 wt. ~, more preferably 0.1 to about 0.9 wt. ~, and most preferably about 0.13 wt. ~ to about 0.5 wt. ~ of a calcium compound, wherein the calcium compound activates the enzymes. Preferred calcium compounds are inorganic calcium salts such as calcium chloride, calcium fluoride, calcium bromide, calcium sulfate, calcium nitrate, calcium carbonate and calcium bicarbonate.
The composition contains 0 to about 8.0 wt. ~ of a stabilizer, more preferably about 0.1 to about 6.0 wt. ~, and most preferably about 0.2 to about 4.0 wt. ~, wherein the stabilizer is characterized by the formula YC02X, wherein X is an alkali metal cation and Y is hydrogen or an alkyl group having 1 to about 6 carbon atoms. Especially preferred stabilizers are sodium formate, sodium acetate and sodium propionate and mixtures thereof.
An alkali metal nitrate such as lithium nitrate, sodium nitrate or potassium nitrate i9 employed as an auxiliary stabilizer in the compositions at a concentration level of about 0 to about 5.0 wt. %, more preferably about 0.10 to about 1.0 wt. %, and most preferably about 0.5 to about 0.9 wt %.
The compositions include about .001 to about 1~, more preferably about 0.01 to about 0.5 wt. ~, and most preferably about 0.02 to about 0.2 wt. ~ of a preservative which prevents attacks by microorganisms on the thickener, enzymes and other organic components. Suitable preservatives are Germaben II~
and Germall II~ sold by Sutton Labs, Ucarcide~ sold by Dow Chemical and Kathon CG~ sold by Rohm & Haas. Methyl parabens , 2~3~3 and propyl paraben lre also useful. Formali~ s less preferred since it reduces the activity of the enzymes somewhat.
The compositions also include a buffer system comprising a mixture of boric acid, an alkali metal hydroxide such as lithium hydroxide, sodium hydroxide, and potassium hydroxide and an alkali metal chloride such as lithium chloride, sodium chloride and potassium chloride, wherein the concentration of the buffer sy~tem i5 about .1 to 5.0 wt. ~, more preferably about 0.2 to about 2.0 wt. ~, and most preferably about 0.3 to about 1.7 wt. %. Other boron-containing systems such as boric oxide, borax, alkali metal borates are suitable, but boric acid is preferred.
Another suitable buffer is tris buffer. Tris buffer is 2-amino-2-hydroxymethyl 1,3-propanediol also known as tris(hydroxymethyl)aminomethane and is used as a buffer in the range pH 7 to 9. Other suitable buffers are NaHCO3, NaCO3, and KH2PO4 in the appropriate parts of the pH range covered by thi3 invention. Other suitable buffers are borax, NaHPO4, and the so called "Good" buffers as listed in the Handbook of Biochemistry, Herbert A. Sobe, ed., CRC Press, Cleveland, Ohio 1970, p 238. The buffers should be made up in the range of pH
about 6 to about 12, preferably in the range of 7 to 11.
The composition includes a detergent active material which can be a nonionic surfactant or a mixture of a nonionic surfactant and an anionic surfactant in a weight ratio of about 2/1 to about 100/1, but a ratio of 3/1 or higher i9 2~93~3 preferred. Combin; ;ons of two or more nonior s and two or more anionics can also be used.
The concentration of the detergent active material in the composition is about 0 to about 7.0 wt. %, more preferably about 0.05 to about 4.0 wt. ~, and most preferably about 0.1 to about 1.5 wt. ~.
The liquid nonionic surfactants that can be used in the present detergent compositions are well known. A wide variety of these surfactants can be used.
The nonionic synthetic organic detergents are generally described as ethoxylated, propoxylated fatty alcohols which are low-foaming surfactants and are possibly capped. The molecules are characterized by the presence of an organic hydrophobic group and an organic hydrophilic group and are typically produced by the condensation of an organic aliphatic or alkyl aromatic hydrophobic compound with ethylene oxide and/or propylene oxide. Practically any hydrophobic compound having a carboxy, hydroxy, amido or amino group with a free hydrogen attached to the nitrogen can be condensed with ethylene oxide or with the polyhydration product thereof, polyethylene glycol, to form a nonionic detergent. The length of the hydrophilic or polyoxy ethylene chain can be readily adjusted to achieve the desired balance between the hydrophobic and hydrophilic group~. Typical ~uitable nonionic surfactants are those disclosed in US Patent Nos. 4,316,812 and 3,630,929.
A preferred class of the nonionic detergent employed i9 the poly-lower alkoxylated higher alkanol wherein the alkanol 137~3 is of 9 to 18 carb atoms and wherein the n~ ~r of mole~ of lower alkylene oxide (of 2 or 3 carbon atoms) is from 3 to 15.
Of such materials it is preferred to employ those wherein the higher alkanol is a high fatty alcohol of 9 to 11 or 12 to 15 carbon atoms.
Useful nonionics are represented by the low foam Plurafac series from BASF Chemical Company which are the reaction product o~ a higher linear alcohol and a mixture of ethylene and propylene oxides, containing a mixed chain of ethylene oxide and propylene oxide, terminated by a hydroxyl group.
Of such materials it is preferred to employ those wherein the higher alkanol is a high fatty acid of 12 to 15 carbon atoms and which contain 3 to 15 alkoxy groups. Examples of such surfactants are C2~s 6EO 3PO, Cl3~5 4EO, 7PO, Cl2l5 lOEO, 5PO. Similar surfactants are members o~ the Plurafac series from BASF. Also useful are Plurafac LF 132 and Plurafac LF
231 and Plura~ac RA30. Lutensol SC9713 and Synperionic LF/D25 are also useful.
An especially preferred type of surfactant is a very high molecular weight surfactant such as Tergitol MDS 42 and Tergitol MDS 32. These surfactants have molecular weights of around 6000. They are very low foamers and are particularly suited to automatic dishwashing. It is estimated by calculation that if the hydrophobe i9 Cl3H~, then Tergitol MDS
42 would have up to 132 ethylene oxide residues and up to 93 propylene oxide re3idues if all the rest of the weight were taken up by one or the other exclusively. Of course, there is expçcted to be a balance between the ethylene oxide and 2~37~3 propylene oxide fr tions. Other useful surf, ~ants are Tergitol Minfoam lx and Tergitol Minfoam 2x. These surfactants have good wetting properties, plus the low foam that is important for effective cleaning in the automatic dishwasher.
Other useful surfactants are Neodol 25-7 and Neodol 23-6.5, which products are made by Shell Chemical Company, Inc.
The latter is a condensation product of a mixture of higher fatty alcohols averaging about 12 to 13 carbon atoms and the number of ethylene oxide groups present averages about 6.5.
The higher alcohols are primary alkanols. Other examples of such detergents include Tergitol 15-S-7 and Tergitol 15-S-9 (registered trademarks), both of which are linear secondary alcohol ethoxylates made by Union Carbide Corp. The former is mixed ethoxylation product of 11 to 15 carbon atoms linear secondary alkanol with seven moles of ethylene oxide and the latter is a similar product but with nine moles of ethylene oxide being reacted.
Also useful in the present compositions as a component of the nonionic detergent are higher molecular weight nonionics, such as Neodol 45-11, which are similar ethylene oxide condensation products of higher fatty alcohols, with the higher fatty alcohol being of 14 to 15 carbo~ atoms and the number of ethylene oxide groups per mole being about 11. Such products are also made by Shell Chemical Company.
Another useful class of surfactants is the anionics.
They are more hostile to the enzymes than the nonionics, but they impart useful wetting and detergency properties to the `

2Qg~3 composition. Ofte~ 'ood soils are dried out, ~specially when baked on or not washed immediately) hydrophobic as in baked egg, or microporous as in potato and cooked starch. In order for the enzymes to work well on these soils, they have to thoroughly wet the soils. For this reason it is useful to add a wetting agent. The anionics are acceptable to the enzymes as long as the anionic/nonionic ratio is less than about 1/3.
It is important to limit the concentration of the anionics in the formula not only to maintain the stability of the enzymes, but also to limit the foam generation in the machine.

2~37g3 Useful anioni include those in the tab~ below:

Ethylene Name Hydrophobe Oxide Units Preferred alkylbenzene sulfonates C9- C15 none secondary n-alkane C8-C24 none C,2-C~8 sulfonates (paraffin sulfonates) soluble esters of alpha sulfonated fatty acids C6-C20 none sulfosuccinate esters C6-C20 none alkyl glyceryl ether C6-C~8 sulfonates alkylphenol ether C~- C~4 1 - 4 sulfates alkyl sulfates C8-C~8 none alkyl ethoxy sulfates Cl0-C20 1-10 1-3 EO, Cll - C13 The preferred surfactants are alkyl ethoxy sulfates C,0-C
with 1-4 ethylene oxide groups, preferably 1-2 ethylene oxide groups, and alpha sulfated and sulfonated fatty acids such as R-CH-(SO3-Na+) COO R' wherein R has about 1 to 8 carbon atoms and R' has 1 to about 8 carbon atoms.
Another group of good wetting agents is block copolymers of ethylene oxide and propylene oxide, especially materials of high molecular weight with low ethylene oxide content.
Examples of such materials are the Pluronics from ~3ASF, especially Pluronic L101, L81, D103, 25R1, 31R1, 31R2, 25R2 as well as the Tetronic and the Tetronic R series. Other useful surfactants include Triton CF 21, CF 10 and the Tergitol 2~37~3 series, especially ~ergitol Minfoam lX, Tergi~ l Minfoam 2X, which are good wetting agents and also relatively low foamers.
The alkylpolysaccharide surfactants are also useful alone or in conjunction with the aforementioned surfactants.
Alkypolysaccharides have a hydrophobic group containing from about 8 to about 20 carbon atoms, preferably from about 10 to about 16 carbon atoms, most preferably from 12 to 14 carbon atoms, and polysaccharide hydrophilic group containing from about 1.5 to about 10, preferably from 1.5 to 4, and most preferably from 1.6 to 2.7 saccharide units (e.g., galactoside, glucoside, fructoside, glucosyl, fructosyl, and/or galactosyl units). Mixtures of saccharide moieties may be used in the alkylpolysaccharide surfactants. The number x indicates the number of saccharide units in a particular alkylpolysaccharide surfactant. For a particular alkylpolysaccharide molecule, x can only assume integral values. Any physical sample can be characterized by the average value of x and this average value can assume non-integral values. In this specification the values of x are to be understood to be average values. The hydrophobic group (R) can be attached at the 2-, 3-, or 4- positions rather than at the 1- position, (thus giving e.g. a glucosyl or galactosyl as opposed to a glucoside or galactoside). However, attachment through the 1-position, i.e., glucosides, galactosides, fructosides, etc., is preferred. In the preferred product the additional saccharide units are predominately attached to the previous saccharide units~s 2-position. Attachment through the 3-, 4-, and 6- positions can also occur. Optionally and 2~3~83 less desirably the~ can be a polyalkoxide chc ~ joining the hydrophobic moiety (R) and the polysaccharide chain. The preferred alkoxide moiety is ethoxide.
rrypical hydrophobic groups include alkyl groups, either saturated or unsaturated, branched or unbranched containing from about 8 to about 20, preferably from about 10 to about 16 carbon atoms. Preferably, the alkyl group is a straight chain saturated alkyl group. The alkyl group can contain up to 3 hydroxy groups and/or the polyalkoxide chain can contain up to about 30, preferably less than 10, most preferably 0, alkoxide moieties.
Suitable alkyl polysaccharides are decyl, dodecyl, tetradecyl, pentadecyl, hexadecyl, and octadecyl, di-, tri-tetra-, penta-, and hexaglucosides, galactosides, lactosides, fructosides, fructosyls, lactosyls, glucosyls and/or galactosyls and mixtures thereof.
The alkyl monosaccharides are relatively less soluble in water than the higher alkylpolysaccharides. When used in admixture with alkylpolysaccharides, the alkylmonosaccharides are solubilized to some extent. The use of alkylmono-saccharides in admixture with alkylpolysaccharides is a preferred mode of carrying out the invention. Suitable mixtures include coconut alkyl, di-, tri-, tetra-, and pentaglucosides and tallow alkyl tetra-, penta-, and hexaglucosides.
The preferred alkylpolysaccharides are alkylpoly-glucosides having the formula:

.

2~37~3 R.O(CnH2nO),(Z)~
wherein Z is derived from glucose, R i9 a hydrophobic group selected from the group consisting of alkyl, alkylphenyl, hydroxyalkylphenyl, and mixtures thereof in which said alkyl groups contain from about 10 to about 1~, preferably from 12 to 14 carbon atoms; n is 2 or 3 preferably 2, r is from 0 to about 10, preferably 0; and x is from 1.5 to about ~, preferably from 1.5 to 4, most preferably from 1.6 to 2.7.
The amount of unreacted alcohol (the free fatty alcohol content) in the desired alkylpolysaccharide surfactant i9 preferably less than about 2~, more preferably less than about 0.5~ by weight of the total of the alkylpolysaccharide. For some uses it is desirable to have the alkylmonosaccharide content less than about 10~
The used herein, "alkylpolysaccharide surfactant" is intended to represent both the preferred glucose and galactose derivèd surfactants and the less preferred alkylpolysaccharide surfactants. Throughout this specification, ~alkylpolyglucoside~ is used to include alkyl-polyglycosides because the stereo chemistry of the saccharide moiety is changed during the preparation reaction.
m e composition contains at least one enzyme at a concentration of about 0.1 to about 5.0 wt. percent, more preferably about .1 to about 4.5 weight ~ and most preferably, about 0.2 to about 4.0 weight ~.
A wide variety of enzymes can be used, but proteases and amylases are preferred. The protease can be from an animal, a vegetable or a microrganism. Bromelain, derrived from plants %~37~3 of the family Brom~~iaceae is useful with or ~ -hout amino acid cysetine. Particularly preferred are subtilisin-type proteases obtained from B. subtilis and B. lichenformis.
Other useful proteases are from B. alcalophylus. Suitable commercial availab e proteases are Maxatase and Maxacal protease from International Bio-Synthetics, Alcalase, Savinase and Esperase from NOVO Industries A/S, Milezyme PA~ from Miles Labs and Proact DU 1000 from Kodak. A comhination of two or more proteases would also be useful in this invention.
Amylase.s useful in this invention are available commercially as Maxamyl and Rapidase from International ~io Synthetics, and Alcamyl and Termamyl from NOVO Industries.
Of the available enzymes, the ones that are preferred are the ones with appreciable activity at lower temperatures, such as Maxamyl and Maxatase.
Combinations of two or more enzymes are useful in this inventlon.
The compositions of the instant invention are prepared by first forming at about room temperature a slurry of water, the thickener and the pre~ervative.
A salt concentrate is made by mixing water, the calcium compound, sodium nitrate, stabilizer, buffer system and any other ionic components at room temperature with stirring.
The dispersion of thickener and preservative, the salt concentrate and water are mixed together with stirring at room temperature. The remaining ingredients, such as surfactant, are added with stirring at room temperature. Last, the enzyme 2 ~ 9 3 7 ~ 3 62301-1825 or mixtures of enzymes is added with stirring at room temperature.
A typical pretreatment composition for the pretreatment of dishware prior to its cleaning in an automatic dishwasher comprise, approximately by weight:
(a) 0.01 to 5.0% of a thickening agent;
(b) 0 to 1.0% of a calcium compound;
(c) 0.01 to 1.0% of a preservative;
(d) 0.0 to 5.0% of a buffer system;
(e) 0 to 7.0% of at least one detergent active material;
(f) 0 to 8.0~ of at least one stabilizer;
(g) 0.1 to 5.0% of at least one enzyme;
(h) 0.0 to 5.0~ of an alkali metal nitrate; and (i) balance being water, the composition has a pH of about 6 to about 12.
For the marketing purpose, the composition is put into a container carrying instructions that the composition is to be used for treating a soiled dish before the dish is washed in an automatic dishwasher.
The invention provides, in an aspect, a method which comprises treating a soiled dish with the composition described herein and washing the thus-treated dish in an automatic dishwasher.
Detailed Description of the Preferred Embodiments Example I:
The following formulas A-F were prepared according to the following method.

~.

2~37~3 The thickener and a suitable preservative were dispersed in about 7.5 to about 8 parts of water using a series 2000 model 84 Dispersator at room temperature to form a thickened slurry. A more dilute thickener slurry can be made by using up to about 40 to 42 parts of water. If the particular thickener chosen is hard to disperse, then the higher amount 18a , 2~7~3 of water is better This made it easier to gf a uniformly thickened product, without fish eyes.
A salt concentrate was made by adding the calcium compound, sodium nitrate, sodium formate, the buffer system and any other ionic components to about 40 to about 50 part9 of water. The mixture was stirred on a magnetic stirrer at room temperature until the salts dissolved, about 10 minutes.
The thickened slurry and the salt concentrate and any remaining water from the formula were added together as follows: the remaining water from the formula was added to the thickened slurry. Then the buffer and salts were added.
The thickened slurry should be as dilute as possible before the salts are ~dded to avoid the formation of fish eyes. The composition was stirred on a magnetic stirrer for 15-20 minutes at room temperature.
The remaining ingredients were added to the thickened slurry plus salt mixture. The enzyme was added last to the composition which was stirred on a magnetic stirrer for 10 minutes at room temperature.

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21~3~3 The test procf~lre used to measure cleani in Examples 1-6 is described as follows:
Twenty-four grams of Quaker Quick Oats, 2g of Cabot pigment grade carbon black (Sterling R, V647) and 400g of tap water were boiled together with stirring until the total weight of the mixture was 260g. The oatmeal was cooled until it reached 120-130F and blended in an Osterizer blender for 30 seconds on ~low grind~. Three grams of this mixture was spread on each plate in a circle of 11 cm in diameter. The plates were baked for two hours at 80C and then stored at room temperature until used. The oatmeal soil contained carbon black to make it visible on the plate. CaCl2 egg soil was prepared by mixing equal parts of egg yolk and 2.5M CaCl2 in a small beaker, using a stir bar. Egg soil was painted on the plate in the shape of a cross with an area of 40 sq. cm. The plates were stored in a constant humidity incubator (50~+2% RH) overnight before being used. After washing, the egg plates were stained with a dilute solution of Eosin Y. This dye preferentially adhered to certain food 80il~, rather than the china plates. It was used as a coloring agent 90 the remaining egg could be seen easily.
The plates were treated with test solutions. The test solutions were applied with a variety of applicators. The plates were then incubated vertically or horizontally at room temperature for 15 min.
Formulations without thickener, as in Example 1, were incubated horizontally. The plates were put in an automatic dishwasher and washed in the presence of 40g of a mixture of 4 parts margarine to 1 part powdered milk and lOg of whole milk, using water of 120F and 300 ppm hardness. At the beginning of the main wash, 80g of a commercial liquid automatic dishwasher product was added.

2~7~3 In Examples 1- the plates were treated c only one half. When the plates were scored, the treated half was compared to the untreated half. For black oatmeal, in Examples 1-4 the plates were rated by eye aS to percent of the surface area still dirty. The S higher numbers mean dirtier plates. The first number in the table is the percent of area still dirty on the treated side, separated by a slash from the percent still dirty of the untreated area. The egg plates were rated by counting the number of 1/4 x 1/4 in. squares still dirty on the treated and untreated sides of the plate. The results are reported as (percent of treated area still dirty)/(percent of untreated area still dirty). Higher numbers mean dirtier plates.
In Examples 5 and 6, the entire plate was treated. The method for scoring the egg plates was the same except that only one score was given because the whole plate was treated. The oat plates were scored in a completely different way. Since the oatmeal contained carbon black the oatmeal could be ea~ily detected by large area view reflectometer. The reflectometer reading was roughly proportional to the log of the weight of the soil remaining on the plate. The highest possible reflectometer reading is Rd=60 for a clean plate.
The plates were slightly off white 90 higher readings were not expected. The Rd of a plate that was washed in a dishwasher, but not pretreated with present invention, was about 20. The Rd of a completely unwashed black oatmeal plate was approximately zero. The dirtier plates have lower numbers and this was just the opposite from Examples 1-4.

2~37~

The viscositi~ as measured in Examples ~ were Brookfield viscosities measured at room temperature uging a #1 spindle at 10 rpms .
The pH was determined by measuring an aqueous solution of the composition at a concentration 10 grams of the composition per liter of water.
The foregoing detailed description of the invention is given by way of illustration only. Thus, variations may be made therein without departing from the scope and spirit of the invention.

Claims (27)

1. A pretreatment composition for dishware which comprises approximately by weight:
(a) 0.01 to 5.0% of a thickening agent;
(b) 0 to 1.0% of a calcium compound;
(c) .001 to 1.0% of a preservative;
(d) 0.1 to 5.0% of a buffer system;
(e) 0 to 7.0% of at least one detergent active material;
(f) 0.1 to 5.0% of at least one stabilizer;
(g) 0.1 to 3.0% of at least one enzyme or a mixture of an amylase enzyme and an alkaline protease enzyme, if said amylase enzyme and said alkaline protease enzyme are both present, then a weight ratio of said amylase enzyme to said protease enzyme being about 100 to 1 to about 1 to 10;
(h) 0 to 1.0% of an alkali metal nitrate; and (i) balance being water, said composition at a concentration of 10 grams of said composition in one liter of an aqueous bath having a pH of about 6 to about 12.

2. The composition of claim 1, wherein said thickening agent is selected from the group consisting of xanthan gum, welan gum, rhamsan gum, carboxymethyl cellulose, hydroxyalkyl cellulose, alkyl cellulose, polyethylene glycol, polyalkylene oxide, polyvinyl alcohol and polysaccharide with beta glycoside linkages and mixtures thereof.

3. The composition of claim 1, wherein said preservative is selected from the group consisting of Germaben II, Ucarcide, formalin, benzoic acid, alkali metal salts of benzoic acid, sorbic acid and alkali salts of sorbic acid and mixtures thereof.

4. The composition of claim 1, wherein said calcium compound is an inorganic calcium salt;

5. The composition of claim 1, wherein said stabilizer has the formula YCO2X, wherein Y is hydrogen or an alkyl group having about 1 to about 6 carbon atoms and X is an alkali metal cation.

6. Composition of claim 5, wherein said stabilizer is selected from the group consisting of sodium formate, sodium acetate and sodium propionate.

7. The composition of claim 1, wherein said buffer system comprises a mixture of an alkali metal hydroxide, an alkali metal chloride and boric acid at a concentration sufficient to adjust the pH of the composition to about 6 to about 10.

8. The composition of claim 7, wherein said alkali metal chloride is selected from the group consisting of lithium chloride, sodium chloride and potassium chloride.

9. The composition of claim 8, wherein said alkali metal hydroxide is selected from the group consisting of lithium hydroxide, sodium hydroxide and potassium hydroxide.

10. The composition of claim 1, wherein said detergent active material comprises a mixture of a nonionic surfactant and an anionic surfactant, a weight ratio of said nonionic surfactant to said anionic surfactant being about 100/1 to about 2/1.

11. The composition claim 1, further including a colorant.

12. The composition of claim 1, further including a fragrance.

13. The composition of claim 1 further including a lipase enzyme.

14. The composition of claim 2, wherein said preservative is selected from the group consisting of Germaben II, Ucarcide, Kathon CG, formalin, benzoic acid, alkali metal salts of benzoic acid, sorbic acid and alkali salts of sorbic acid and mixtures thereof.

15. The composition of claim 14, wherein said calcium compound is an inorganic calcium salt;

16. The composition of claim 15, wherein said stabilizer has the formula YCO2X, wherein Y is hydrogen or an alkyl group having about 1 to about 6 carbon atoms and X is an alkali metal cation.

17. Composition of claim 16, wherein said stabilizer is selected from the group consisting of sodium formate, sodium acetate and sodium propionate.

18. The composition of claim 16, wherein said buffer system comprises a mixture of an alkali metal hydroxide, an alkali metal chloride and boric acid at a concentration sufficient to adjust the pH of the composition to about 6 to about 10.

19. The composition of claim 18, wherein said alkali metal chloride is selected from the group consisting of lithium chloride, sodium chloride and potassium chloride.

20. The composition of claim 19, wherein said alkali metal hydroxide is selected from the group consisting of lithium hydroxide, sodium hydroxide and potassium hydroxide.

21. The composition of claim 18, wherein said detergent active material comprises a mixture of a nonionic surfactant and an anionic surfactant, a weight ratio of said nonionic surfactant to said anionic surfactant being about 100/1 to about 2/1.

22. The composition claim 21, further including a colorant.

23. The composition of claim 22, further including a fragrance.

24. The composition of claim 23 further including a lipase enzyme.

25. The composition of claim 24, further including an anti-foaming agent.

26. The composition as defined in any one of claims 1 to 25, which has a Brookfield viscosity of 20 to 1,000 cps and is contained in a commercial container carrying instructions that the composition is to be used for treating a dish before the dish is washed in an automatic dishwasher; and in which the enzyme is activated by the calcium compound.

27. A method which comprises:
treating a soiled dish with the composition as defined in any one of claims 1 to 25, and washing the thus-treated dish in the automatic dishwasher.