US3684576A - Oven cleaning method and product - Google Patents

Abstract

THE APPLICATION OF CERTAIN OXIDATION CATALYSTS TO BAKEDON FAT DEPOSITS ON OVEN SURFACES REDUCES TEMPERATURE OF COMPLETE DECOMPOSITION. OVEN CLEANING COMPOSITIONS CONTAINING METAL ACETYLACETONATES, HOPEALITE CATALYST, SODIUM CARBONATE, COBALTO-COBALTIC OXIDE, MANGANESE DIOXIDE, PLATINUM METALS AND COMPOUNDS OF PLATINUM METALS, ALONE AND IN COMBINATION WITH SURFACE ACTIVE AGENTS, PENETRANTS AND CATALYST PROMOTERS SUCH AS FREE ALKALI, ARE DESCRIBED.

Description

AU 165 EX 3,684,576 Patented Aug. 15, 1972 day high temperature ovens, i.e., significantly below 800 3,684,576 F., by applying to the baked-on residue an oxidation OVEN CLEANING METHOD AND PRODUCT Howard Eisen, Fair Lawn, N.J., and Joseph A. Feighan,

Cheltenham, Pa., assignors to Glamorene Products Coromfion Clifton NJ 5 to our invention we have provided a substance which Braking czmfim'mfion of application Ser. can be applied to an oven surface to cause baked-on fat 619,574 M 1 1967. This application Jam 30, residues to more rapidly oxidize andwaporize at a tem- 970 s 7 3 1 perature near the maximum operating temperature of I t, (:1, (323 1/00 present-day conventional ovens, i.e., 450-520" F. The US. Cl. 134-2 7 Claims catalyst system will lower the temperature at which cleaning occurs from 800 F. down to temperatures b'plow 600 F. and in some cases, as low as 400 F. to 450-" F. ABSTRAT OF THE DISCLOSURE Studies of air oxidation of the glazed fat deposits The application of certain oxidation catalysts to bakedfound in dirty Ovens, in absence of yh h on fat deposits on oven surfaces reduces temperature of dcfnollsn'ated that P "moval of 5 y complete decomposition. Oven cleaning compositions conoxldijllon the Substancfl follows a p ure-time taining metal acetylacetonates, hopcalite catalysts, sodium l'elatlonshlp- A! Complete OXldatlOn carbonate, cobalto-cobaltic oxide, manganese dioxide, of fat fieposlts to a P Steel. Surface wmfilke platinum metals and compounds of platinum metals, alone F mlnllteth Rcduclflg the {emperamre 3 and in combination with surface active agents, penetrants "q from {mnutes 0f heallflg i0 and catalyst promoters such as free alkali, are described. achleve the 5mm Complete OXIdatlOn, and at (797 F.) complete oxidation occurs in approximately 45 minutes. At 400 C. (752 F.) complete oxidation re- This application is a continuation of Ser. No. 619,574, quires one 9 P 45 I and at fil d Man 1, 19 7, now d d 25 complete oxidation requires about 6 hours.

This invention relates to a method of cleaning surfaces l belPw lmle Praclical Oven having a tightly-adhering film of baked-on fats and F 8 Pf 15 Obtalfled- At thfifc greases, and to a product for assisting in carrying out 18 mile ible effect after 6 hours, and at 200 C. (392 this method. More particularly, the invention relates to f $8 8 Visible effect 43 ou an oven cleaner and to a method f cleaning oven 30 The oxidation catalysts found useful according to this one of the most disagreeable tasks f ing the house. invention include certain metal derivatives of 2,4-pentanewife is the periodic cleaning of the oven of her kitchen dlonfl. also called eta acelylflceiolnalfish cobalt, stove. Ovens accumulate baked-on deposits of various Vanadyl and mflfllaneifl salts Particularly usefulfood origin which adhere tightly to the enamel surfaces amP1es s s)a 'of the oven. The deposits are organic carbonaceous materials, and most usually result from the spattering of (CH'COCFCOCHSMQ fats and oils from foodstuffs during cooking thereof. (CH,COCHCOCH,),Mn, (CH,COCHCOCH,),Mn, and Proteins and carbohydrates may also contribute, but (Cl-LCOCHCOCHQNO. usually to a lesser extent. These deposits form a lacquer- 40 Other oxidation catalysts found useful according to like i which extremely diffiwll Wi h the invention include those known as hopcalite type catordinary soap and water. alysts, in modified form. One such catalyst, prepared as One current solution to this problem is an oven which described in Kearby in "Preparation and Development is built with suflicient insulation and the appropriate of Catalysts," Standard Oil Development Co., Linden, equipment to operate at a temperature of about 800' F. N.J.-Repcrt No. CD-SP-S 1, has an approximate com- Under this extreme temperature, the baked-on residues position of MnO,, 30% Q10, 15% C0 0,, 5% are rapidly oxidized and vaporized, leaving only a resi- Ag,0. Each compound is separately prepared by precipidue of fine ash. tation in a water solution, then brought into slurry and The other current approach to the problem involves mixed. The a o is precipitated onto the slurry of the th f a v l aner which is applied by the house- 50 first three. The sample is then washed three times, dried wife and which is formulated to dissolve the deposit, or in an oven at 140 C. and powdered. at least soften it so that it can be wiped awsy. Another group of catalysts which is useful according to The cleaner may be one of two general typ s. One this invention are the platinum metals, including type, which is marketed variously as a jelly, a paste or an platinum, ruthenium, rhodium and palladium. Catalytiaerosol composition, relies heavily upon free alkali as its cally active compounds of these metals may be used, such active ingredient. The second basic type of oven cleaner as the oxides, .cerates, manganates or manganites, chrorelies upon methyl chloride or some similar solvent and t or h it d d m the compositions y include v ns stem! or agents Other suitable catalysts include Na,co,, 00,0, (codesigned to lift the baked-on fat layer away from the balto-cobaltic oxide) and MnO,. surface of the oven. Thus, the catalysts suitable for use according to this The oven cleaners based on strong alkali are generally invention ar those from the group consisting f the successful in that they will clean the surface of the oven metal acetylncetonates, hopcalite catalysts, sodium carif used properly. It is well known, h wer, that their use bonate, cobalto-cobaltic oxide, manganese dioxide, is extremely messy and is hazardous to the extent that platinum metals and compounds of platinum metals. severe burns may result if the cleaner comes in contact 66 These catalysts are useful by themselves or with with the skin of the user. The solvent-based cleaners, on diluents, such as carbon. Each of these materials can the other hand, are efiective only for fat which has not also be used in various admixtures with each other to yet burned onto the surface of the oven. Once the latter provide various desired effects. Coloring materials may has occurred, the solvent-based cleaner is ineffective. be employed, and various masking agents may be used We have now found that the baked-on deposit on the 70 to avoid unwanted colors.

oven surface may be removed by heating to temperatures significantly below those temperatures used for presentcatalyst which has the effect of reducing the temperature at which oxidation of the surface film occurs. Accoring In certain cases, it has been advantagesous to employ small aniounts of catalyst promoters with the catalyst described above. Particularly good results have been obtained with the catalysts modified with potassium hydroxide and sodium carbonate as alkaline promoters. Sucrose and manganese dioxide have also been useful in this capacity. Generally speaking, a level of about 1% of promoter based upon the weight of the catalyst has been used to advantage.

The catalyst described above may also be advantageously supported on carriers such as chromia and alumina. Methods for obtaining chromia type catalysts are described in the article by Feighan and Davis, Journal of Catalysis, vol. 4, p. 594, 1965. Preparation of this type catalyst is accomplished by depositing a catalytically active substance, such as a metal acetylacetonate, on the base ceramic material in accordance with procedures known in the art.

The catalyst of the present invention is most conveniently applied to oven surfaces as a paste or gel containing a uniform suspension of catalyst, catalyst promoter and other desired ingredients, including surfactant, thickener, oxygen donor and extender.Triton X-lOO is a suitable surfactant and penetrant, and may be used at a level up to about 0.5%. A level of 0.1% is preferred. Triton X-100 is an alkyl aryl polyether alcohol, i.e., actylphenol condensed with moles of ethylene oxide. Sugar-based surfactants, such as certain sucrose derivatives, as well as polyoxyethylated compounds, may also be used. Suitable thickeners include carboxymethyl cellulose, methyl cellulose, and Polyox, a trade name for a water-soluble, highly polymerized ethylene oxide. A suitable oxygen donor is KNO; preferably at a level of 0.5%. Suitable extenders include sodium aluminate and sodium silicate --Al,0,, preferably at a 0.5% level. Other additives, promoters, color pigments and the like may be used. Suitable thickeners include carboxymethyllevel. The balance of the composition is liquid and preferably is water.

The following examples further illustrate the process of this invention.

EXAMPLE I The efiectiveness of various oxidation catalysts in removing baked-on fat deposits was assessed using the procedure described below. Stainless steel plates, 1" x 4" in size and approximately ,4 thick, were highly polished to present a nonporous surface. These plates were coated with layers of animal fats by brushing the fat onto the surface. The plate was then heated to cause partial decomposition of the fat. and successive layers were deposited. The deposited material was then heated in a Fisher burner in an open flame at temperatures appzoaching 800' C. until a hard glazed coating of dark brown to black coloration was obtained, similar to carbonized fatty solids found in ovens. Approximately 2-4 mg. of fat were deposited per square centimeter of plate surface.

Powdered catalyst was applied to about 40% of the total plate surface, the balance of the plate acting as a control. To assure an even coating of catalyst, the fat deposit was first moistened with a thin film of alcohol. The dry catalyst was then rubbed or spread on the fat deposit. The solvent aided the dispersion process and on drying gave a relatively even catalyst deposit. Where catalysts activators, such as sodium hydroxide and sodium carbonate, were used the activators were dissolved in the alcohol as a 1% solution and applied directly to the fat deposit.

The stainless steel plates with the fat deposit and catalyst thereon were then heated for specified lengths of time at specified temperatures. On completion of the heat treatment, the activity of each catalyst was evaluated in accordance with the following visual rating system:

A-no effect noticeable-fat deposit still glazed. Bbare1y detectable effect on fat deposit. C-intermediate effect on fat deposit, surface disrupted.

4 Dstrong effect, some small amount of steel surface visible. E-surface metal easily observable, large portions of surface cleaned.

Table 1 below summarizes the results obtained.

TABLE 1 Catalyst Temp, Time Catalyst promoter C. (hrs) Rating 400 c 40o c 400 14 D 300 is C 300 34 E 400 M D 400 x E 400 x E 350 i 1) Mll02'N82COs.... 350 l D MnOyKOiL. 350 1 C 300 1 ii 300 l B 300 1 A 360 1 D 360 1 11 850 1 11 300 l A 800 1 B 300 1 B NBzCOs 270 a C NBICOrMIlO 270 3 C MnOrKOI'L. 270 8 B 800 l D NazCOs B00 1 I) 270 8 C NarCOs 270 8 C M110: 850 l C MnO NmCOi 360 l B 800 836 C Na:CO 800 2 B MnOrNazCO 300 2 B MnOz-Kolln 800 2 B NazCO 800 8% O O 300 8}? C M110: 860 E MnO; B00 8% B PtonO MnO1-Ns;C0;.... 800 1 B MnO: 30% Duo, 15% 00101. 6% M10; M10 precipitated onto slurry st ilrst three.

EXAMPLE II A series of oxidation catalysts were prepared and evaluated as agents for removing baked-on fat deposits. For this series, a number of stainless steel sample pans approximately 1" in diameter, and having a ,4 lip were cleaned in hot potassium hydroxide solution, rinsed well and then air dried. The interior surface of these pans were then coated with animal and vegetable fat. The greased pans were heated at 350' C. for approximately 30 minutes in a tube furnace with free access of air to form a hard glazed deposit of fat having up to about 60 mg. per square centimeter.

A dry, powdered catalyst was added to each pan, and slurrled in the pan with a few drops of methyl alcohol to obtain a coating of uniform thickness over the fat deposit. The deposit was then air dried for several hours to remove the solvent. Duplicates of each sample were then heated for two hours, one at 232 C. and the other at 288' C. and the weight loss occasioned by volatilization by the fat deposit was determined. Table 2 below summarizes the results obtained in these tests.

TABLE 2 Catalyst Promoter EXAMPLE m A suitable composition for use as an oven cleaning composition according to this invention has the following formula:

Water, balance.

The composition is prepared by mixing the ingredients to form a paste. The paste is used by applying it to the surface of an oven having backed-on fat deposits and operating the oven at its maximum temperature from two to three hours.

We claim:

1. A method of removing a deposit of baked-on fats from oven surfaces comprising the steps of (1) applying to the deposit an oxidation catalyst selected from the group consisting of the cobalt, manganese and vanadyl acetylacetonates and soidum carbonate, and (2) heating the deposit for a time and at a temperature suflicient to cause complete oxidation of the deposit.

2. The method of claim 1, wherein the catalyst is applied to the baked-on fat deposits of an oven as a uniform suspension of powdered catalyst in water.

3. The method of claim 2 wherein the suspension of catalyst in water additionally contains a catalyst promoter selected from the group consisting of potassium hydroxide, sodium carbonate, sucrose, and manganese dioxide, at level of about 1%, based on the weight of the catalyst.

4. An oven cleaner consisting essentially of an oxidation catalyst selected from the group consisting of the cobalt,

manganese and vanadyl acetylacetonates and sodium carbonate, which will catalyze the oxidative deterioration of baked-on fat deposits at a temperature below about 600 F. within a three hour period of time.

5. The oven cleaner of claim 4, wherein the composition additionally contains a nonionic surface active agent and a catalyst promoter selected from the group consisting of potassium hydroxide, sodium carbonate, sucrose, and manganese dioxide, at a level of about 1% based on the weight of the catalyst.

6. An oven cleaner adapted for use in oven cleaning processes conducted at a temperature below 600 F. within a one hour period of time consisting essentially of cobaltous acetylacetonate as an oxidative catalyst and about 1% by weight of the catalyst of potassium hydroxide.

7. An oven cleaner in the form of a paste adapted for use in oven cleaning processes consisting essentially of 0.1% of an alkyl aryl polyether alcohol as a penetrant, 0.5% methyl cellulose as a thicknener, 0.5% catalyst of cobaltous acetylacetonate with about 1% by weight of the catalyst of sucrose and potassium hydroxide, 0.1% miscellaneous color pigments and a balance of water.

References Cited UNITED STATES PATENTS 3,266,477 8/1966 Stiles 126-273 3,271,322 9/1966 Stiles 252-428 3,460,523 8/ 1969 Stiles et a1. 126-19 3,498,927 3/1970 Stiles 252-451 3,549,419 12/1970 Stiles 134-2 MAYER WEINBLA'IT, Primary Examiner- U.S. Cl. X.R.

P0405) UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION tent No- ,576 Dated August 15, 1972 Inventor) Howard Eisen and Joseph A. Feighan It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

' Col. 2, lines 34 and 35, the formula should be on one line as follows: -(CH3COCHCOCH3) 2C0, (CH3COCHCOCH3) Co,-;

Col. 3, line 25, "actylphenol" should be -octylphenol-;

Col. 3, line 31, after "KNO insert a comma I Col. 3, line 35, delete". Suitable thickeners include carboxymethyl-" and insert --at levels up to l/8%, and preferably a O.l%--;

Col. 5, line 16, "backed-on" should be bakedon-;

Col. 5, line 24, "soidum" should read --sodium--;

Col. 5, line 34, before "level" insert -a; and

Col. 6, line 19, "thicknener" should be --thickener.

Signed and sealed this 27th day of March 1973.

(SEAL) Attest:

EDWARD M.PLETCHER,JR. RoBEP T (EOTTSCHALK I Attesting Officer Commissioner of Patents