CA1047903A - Oven cleaning compositions - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE
Compositions useful for oven cleaning comprising an alkali metal hydroxide and an alkanolamine in aqueous solution;
wherein a relatively low concentration of alkali metal hydroxide and the alkanolamine combine to provide a cleaning capability equal to that of conventional oven cleaners having high caustic concentrations.

Description

~L~147~3 This invention relate~ to oven cleaniny compositions.
More particularly, th~s invention relates to oven cleaning com-positions having a low caustic concentration and yet a cleaning capa~ility equal to conventional, high caustic oven cleaners.
Ovens are subjected to heat and are liable to soiling ~y ~aked on organic deposits. The soiling matter deposited consists of a complex organic mixture of natural fats and other deposits from the cooking of food. ~hen heated at normal oven temperatures, this soiling matter is converted into an infusible polymeric mass in which part of the organic màterial may also be charred. Detergents, scouring powders and similar cleaming products, although highly efficient for removing normal greasy soiling matter, are not usually adequate for removing baked-on soil of the type found in ovens.
The removal of this type of soil is there~ore a con-siderable problem, requiring powerful chemical or physical `actiOn~ Among the most e~fective chemical compounds known for this purpose are the caustic alkalis such as sodium or potassium ;;-~
h~vdroxide. They may be applied directly by brush or sponge, or

2~ more conveniently by means of an aerosol spray. Products of t~s type, although efficient in their action, suffer from a nu~ er of major disadvantages. On~ disadvantage is that such ;i; ;
products when applled to soiled oven surfaces ~ust attack the ~ `
soiling matter from the outer surface, while the most severe charring and polymerization is generàlly present in the interior of the soil layer, adjacent to the oven wall. This makes cnleaning more difficult~ Secondly, because of the nature of the caustic alkalis and of conventional oven cleaaing compo~
sitionæ having a hi~ concentration of caustic alkali, it has been necessar~ ta emplo~ considerable safety meaaures in their u~e~ T~u~, the advantage of providing an efficient oven cleaner ~;~
with a low level of caustic alkali is apparent. ~;

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l0~7sa~
~lkalis less alkaline than caustic soda are not very effect~ve ~n.,hydrolyzing baked-on deposits in a short time of application, and consequently are not efficient oven cleaners, In the prior art, various compositions for use in hard surface or oven cleaning, have been disclosed w~ich utilize caustic alkali as the predominant cleaning ingredient. U.S.
Patent No. 3,7lS,324 discloses a sto~e-cleaning composit1on com-prising from 10-40~ sodium hydroxide, in addition to other ingred~i`ents~.~ncludIn~.tr~*.thano~lamine. U.S. Patent Nos. 2,992,99 and 2,097,737 discl~se metal cleaning compositions comprising at ::~
least 10% and 6%, respect.vely o~ an alkali metal hydroxide, in addition to other ingredients including alkanolamines. These patents do not disclose the l-ow caustic compositions of the :~
present invention.
A number of oven cleaning compositions have been dis- ~ :~
closed in the prior art whi~h utilize as~little~as 1~ of a ~;
caustic alkali; however, these compositions comprise additional ingredients for cleaning which are not contemplated in the ; ;-compositions of the present invention. For example, U.S. Pa~nt .
No. 3,644,210 discloses an oven cleaner comprising fr~m 1-20% .
. of alkali metal hydroxide, an ethoxylated alkanolamide, and numerous other ingredients which can be substituted in toto ~or . ~.
the alkali metal hydroxide. U.S. Patent No. 3j625,859 discloses a composition comprising an alkali metal or ammonium salt of a .
styrene-maleic anhydride~; copolymer in addition to the caustic.
U.S. Patent-l~3,03l,408 discloses a composition comprising addi-tionally an alcoholic solvent, flow retarder, and amphoteric deter~ent, U.S, Patent 3,591-,416 discloses an oven cleaning -`
composit~.~on compr;sing 9.9% sodium nitrate and.l~ sodium ~ drox~de, -.
"' ' .~'.

~04~9~3 South ~frican Patent No. 68/6992 to S.C. Johnson and Son, Inc, entitled CLEANING COMPOSITI~N ~described in Chemical Abstracts, Volume 71, 103474 C (1969)~ discloses an oven clean-ing composition containing no alkali metal hydroxide and con-sisting essentially oE primary, secondary, or tertiary amines and includes builders such as carbonates, silicates or ; phosphates as the predominant source of alkalinity.
None of these prior art patents disclose oven clean-ing compositions contemplated in the present invention, which .
comprise a low concentration of alkali metal hydroxide and an alkanolamine. Oven cleaning compositlons are known which comprise a concentration of alkali metal hydroxide, an alkanolamine, and an alkylene glycol aryl ether. However, as described in U.S. Patent NoO 3,663,447, these latter two .
ingredients are combined for use as an "accelerator composition" - :
to increase the effectiveness of the alkali metal hydroxide.
..The patent expressly states the alkanolamine when used without tfie ether has substantially no accelerating effect on the alkali metal hydroxide.

Thus, the oven cleaning compositions disclosed in ;:
.the prior art or known in the oven cleaning art do not . :
recognize or anticipate the use of alkanolamines in combination with a low concentration of an alkali metal hydroxide to pro~
vide an oven cleaning composition equally effective as conven-tional oven cleaning compositions with hlgh concentrations of caustic alkali.
According to the present invention, oven cleaning compositions are provided which comprise by weight from about 0.5% to about 4.0% of an alkali metal hydroxide; rom about :

1.0~ to about 20.0% of an alkanolamine selected from the group ..
consisting of: monoethanolamine, aminoethylethanolamine, monoisopropanolamine, N,N-diethylethanolamine, N-methylethanol~

.. . . . . ..
: ~ . . . . ~ -: . . - - : .

~L~479~3 amine, d~glycolamine, diisopropanolamine, -triisopropanolamine, isopropanolam~ne, dimethylethanolam~ne, N,N-diisopropylethanol-amine, diethanolamine, N-methyldiethanolamine and N ethyl-diethanolamine; and up to about 98.5% water.
Some of the advantages provided by the oven cleaning compositions of the present invention are the reduction of caustic alkali and the increase in cleaning.
-- The oven cleaning compositions contemplated in this invention may contain various additional ingredients which aid in~-providing nan effective oven cleaner, such as for example, bentonite, coconut oil fatty acid, lauryl alcohol, and propellant.
Bentonite is useful as a thic~ener and helps in preventing run off of the oven cleaning composition from the $urface to be cleaned. Since an oven has both vertical and horizontal sur- ~ ~
faces, the thickener concentration may be varied so as to pro- ~ -vide an efficient medium for the composition so that all oven ~urfaces are ef~ectively cleaned. Other thickeners which may ~e utilized are polyoxyethylene compounds, carboxymethylcellulose~
ox titanium dioxide. Various soaps and detergents such as coconut oil fatty acid or aluminum stearate, may be utilized in the present invention to increase solubility of the ingre~
dients. Other solubilizers include lauryl alcohol~l methyl-cellulose, or l,l,l-trichloroethylene. Some of the propellants suitable in the compositions of the present invention are .
propane, pentane, butane, or the halogenated hydrocarbona.
It is not intended to limit the present invention to any of these specificall~ identifled additives because various other oven cleaning additives ma~ also be used.
In determining the effectivaness of the oven cleaning compositions of the pre$ent invention, the following procedures have been utilized.

10~903 First~ an oven stain composition which would likely occur ~n househo;ld ovens was prepared as shown in Table I below:
~' ~ABLE I -' ~ngredient Weight of Ingredient ~ '~
Peanut odl 45 g. ~, Corn oil 25 g.
Cherry p~e mix 25 g. "-~round beef 25 g.
Ground pork 25 g.
Sodium chloride 1 g.
Sodium glutamate 1 g. ~i, !',;, , ;j Water 25 g. '`'~
The ingredients shown in Table I were mixed in a pan and coo~ed in an oven at 400F for two hours. The cooked material was ,,~ , filtered through glass wool, storèd in a glass bottle, and ', ' ' , before testing the bottle was shaken.
Effectiveness ofi an oven cleaning composition is ~elated to the type and nature of the stain to be removed. , ; , 2a Thus, applicatlon and curing of the stain composition to a test ,,','~
surface is important. Approxiamately 0.28 to 0.30 grams of ,~
the above stain composition was placed on a 4-1/2" x 4-1/2" ';
,,- , porcelain test panel. The stain composition was spread as ' , ' uniformly as possible over the test panel surface with a flat spatu~a. Stain material was added or removed from the test ~ ' ' panel until 0.25 grams of stain material remained. ~ ~
. -': .
The stained panels were oven cured in the following manner and as-will be discussed~belo~, curing was performed in vax~ous per~ods of t~me and at Yarious temperatures in order ~ ~-to ~roduce sta~n~ o~ ~ar~ing,difficult~ of removal. Six `~
sta~ned panels were placed in a baking pan. Another baking pan ;

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~47903 was used as a cover. The pan and cover were shut tight with hand-tightened screws and wingnuts. Since it was found that any air currents affect the uniformity of the cured stain, the pan and`cover were sealed with aluminum foil. Three sets of pans and covers (each containing six porcelain test panels) were placed on the three shelves (one set on each shelf) of a "slue M" Model OV-490-A-2 constant temperature oven -~and cured at a specified temperature for a specified time. The oven was accurate to approximately ~ 2F. The oven was ~
equilibrated to the required temperature; the ov~n door was ;-;
opened and the pans placed in the oven as quic~ly as possible. ~ ~a The tim~g was begun with the closing of the oven door. This meant that at the start of the cure, the oven temperature was Belo~ the thermostat setting. After the required length of t~me, the pans were removed from the oven and allowed to cooi to room temperature. The stained panels were then removed from the pans. De~pite all precautions/ the aured stain would usually;no,b be completely uniform. Some stained panels would ~ave areas in which there would be little stain and other areas with more stain. Those panels with extreme variations of stain density were eliminated~
I'est of the oven cleaning compositions of the ~resent invention were performed with formulations con~aining the following ingredients listed in Table II:

1~47g03 T`~BLE II ~
Ingredient Weight Percent of Ingredient ~ -Bentonite 2.5 Sodium hydroxide *
Monoethanolamine *
Coconut oil fatty acid 1.0 50/S0 Isobutane/n-butane 1.5 ;
Water (deionized) to 100% total * The weight percent of this ingredient has been varied to ~-determinP the effective range of proportions of this lngredient ~ -in the oven cleaning compositions.
The oven cleaning compositions were prepared in 300 ;~
gram batches as follows: The approximate ~weight of aqueous bentonite concentrate (to yield a final bentonite concentration of 2,5%~ was weighed linto a 500 ml. Erlenmeyer flask into which ~ ~-had been placed a two-inch teflon coated magnetic stirrer bar. ;
Additional water (as required~was added. Then the sodium hydroxide was added, and the dispersion was s~irred unt~
uniform. The monoethanolamine was added and the dispersion was stirred briefly. Then the coconut oil fatty acid was added and the dispersion was again stirred until uniform. Two .
hundred grams of the composition was weighed into an aerosol ~ `
can. The can was crimped and pressurized with 3 grams~o~ a propellant mixture. The compositions either were prepared, pre~surized and immed1ately used, or prepared and stored over-night at around 85F in a crimped, unpressurized aerosol ¢an and pressurized be~ore use.
Each o~en cleaning composition was tested on the

4-1/2" x 4~1'/2" porcelain stained panels. Preliminar~ tests - `~
were perfo~med in which the compositions were not aerosolized, ~ut were applled to the stained panels with a paint brush. ~`~

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1~)47~03 The cleaning was found -to be inferior to aerosol application.
All further tests used aerosol application. Since the housewife would not be concerned with the quantlty (i.e. weigh-t) of stain remaining in her oven after cleaning but rather with the area of the oven in which,stain remained after cleaning, "percent cleaning" was defined as the percent of the area of the 4-1/2"
x 4-1/2" stained panel which, after cleaning, was free of stain.
The percent cleaning of each stained panel was estimated by eye.
The same person estimated the percent cleaning of all stain 10 panels to eliminate the varying bias from person to person. ~-A factor which was considered was the accuracy in estimating the percent cleaning of each stained panel. Table III below indicated the estimated accuracy in determining the average percent cleaning of the stain panels.
TABLE III -% Cleaning Range of Accuracy 0-2 ~ 0.
2-10 + 1%
10-30 - 3% ;
2030-80 + 5%
80-90 + 1% ;
90-95 + 0 7%
95-100 + 0.5%
Where the range of accuracy in determining the percent cleaning was very critical, such as with 0-2% and 95-100%, the number of stain panels tested was increased in order to ascertain the reliability of the original test. - ~-~
As stated previously, difficulty in removing a stain is affected by the conditions used in curing the stain~ i.e., 30 period of time of curing and temperature. In order to `~

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16;)47903 illustrate the effectiveness of the oven cleaning compositions of the presen-t invention, stains of varying degrees of diffi-culty of removal were prepared, as shown below in Table IV.
These stained panels were treated with a 3% sodium hydroxide solution for a six-hour period, lightly rubbed with a sponge, and rinsed with cold water. In all examples that follow, the `; -;
percentages of sodium hydroxide listed are the percentages -added to the compositions. Since a constant quantity (1%) of -~
coconut oil fatty acid is added to each composition, 0.15% of ~
10 the s~iUm hydroxide is neutr~l~zed ~ thé fat~y ac~ There- ~ -fore, the percentage of active sodium hydroxide in all compo-sitions listed is 0.15% less than the number shown (i.e., a 3% sodium hydroxide test solution contains 2.85% free sodium hydroxide). In all oven cleaning tests described below, only ~;~
the variable alkali metal hydroxide or alkanolamine is stated.
It should be noted that the rem~n~io~th~ ~ve~cL~an~n~
composition has been kept constant as described in Table II.
TABLE IV
Effect of Curing Conditions on Simulated Oven Stains Test Composition: 3% NaOH
Experiment No. 1 2 3 4 5 Curing Time; Hrs. 1.0 1.25 1.25 2.0 1.5 ~`

Curing Temperature O ' 425 450 460 450 475 Reaction Time: Hrs. 6 6 6 6 6 Stain Removal % 99.6 94.8 89.0 70.0 ~50-60 These results demonstrate that a stained panel, cured for one hour at 425F, is easily cleaned by treatment for six hours at room temperature with a 3% sodium hydro~ide solution.

Increasing the curing temperature to 450F, and the curing ~ ~
time to 1.25 hours, decreases the cleaning to 94.8%. The .~ -effect of curing time is shown in experiments where the -curing temperature is maintained at ~50F, but time is increas-ed to two hours. In this situation, the ~ removal is reduced to 70.0~. In con-tras-t, -the effec~ of increasiny the curing temperature 10F, while maintaining the time at 1.25 hours is shown in Experiment 4. In this case, the percent cleaning is reduced from 94.8% to 89.0~. Experiment 5 shows the effect of increasing the curing temperature an additional 15F to 475F, while increasing curing time to 1-1/2 hours. In this experiment, the percent soil removal is reduced to approxi-mately 55%. Based on these results, an arbitrary value for -~
degree of difficulty was assigned to each of these stains.
These degrees of difficulty are listed in the following Table V. Degree of difficulty is defined by the following equation:

Degree of Difficulty = 10000 % Stain Removal of 3% NaOh (6 hours) TABLE V

Degrees of Difficulty of Standard 5tains - Used in Experimental Program Experiment No. 1 2 3 4 5 Curing Time: Hrs. 1.0 1.25 1.25 2.0 1.5 Curing Temperatùre: ~F 425 450 460 450 475 Degree of Difficulty 100 105 112.5 143 167 These stains of varying degrees of difficulty of removal have been prepared to illustrate the effectiveness of the novel oven cleaning compositions of the present invention -.
and have been utilized in the follo~ing experiments. It should be noted that the 112.5 degree of difficulty stain would most fre~uently be encountered in a household oven. -The 100 stain is easier to remove and the 143 stain is more difficult to remove than those normally encountered, but the combination of these standard stains provides a simple means ~ ~-1~47903 for measuring the performance oE -the oven cleaning compositions of the present invention. '~
In order to measure the performance of these composi- ~ -tions accurately, the range of stains was utilized so that per-formance would not be dependent upon the stain to be removed.
In this regard, composition testing on the 167 stain was discon- ;
tinued due to difficulty in obtaining accurate and reproducible results.
The following experiments illustrate the unexpected ;~
effectiveness of oven cleaning compositions comprising a low concentration of alkali metal hydroxide and an alkanolamine in aqueous solution.
Table VI illustrates the reduction in cleaning when the caustic concentration is reduced from the 3% used to deter-mine the standard stain, to 2%. ~ , TAsLE VI

Effect of NaOH Concentration Reduction on Stain Removal of Standard Stains ~

Experlment No. 1 2 3 4 5 6 7 8 `
Standard Stain 100 100 105 105 112.5 112.5 143 1~3 ~

Caustic Concen- 3 2 3 2 3 2 3 2 `
tration; % Wt.
Stain Removal;% 99.6 98.1 94.8 79.0 89.0 79.0 70.0 23.0 : .
Table VII illustrates the unexpected advantages of the oven cleaning compositions of the present inventlon. Referring to the values for 2% and 3% caustic alone given in Table VI, it -can be shown that addition of a small amount of alkanolamine increases the cleaning capabiltiy of these compositions to a level equal to or greater than that of the higher caustic compositions. ~ , -~04~90~
TABLE VII
...._ Effect oE Addition of 5% Monoethanolamine to Composition of 2% Sodium Hydroxide on _ Removal of Standard Stains Experiment No. 1 2 3 4 Standard Stain 100 105 112.5 143 Stain Removal; % 99.7 96.6 96.2 88.0 It is evident that for each standard stain, the oven cleaning compositions having 2% caustic are not only more effi-cient because of the addition of 5% of an alkanolamine, butunexpectedly, these compositions are also more efficient than the 3% caustic compositions.
In order to emphasize th~s unexpected efficiency in the oven cleaning compositions of this invention, Tables VIII ;
and IX are presented. ~ ~
TABLE VI I I ~ :
Effect of Addition of Small Amounts of Monoethanolamine to Composition of ~ Sodium Hydroxide on Stain Removal __ of 100 Standard Stain Experiment No. 1 2 3 4 5 6 Sodium Hydroxide; ;~
% Wt. .5 .5 1 1 2 2 ....~ .
Monoethanolamine; ~;-; `~
% Wt. 0 1 0 1 0 5 Stain Removal; % 5.6 81.0 82.0 89.9 98.1 99.7 TABLE IX
Effect of Addition of Small Amounts of Monoethanolamine to Composition of 30Sodium Hydroxide on Stain Removal of 105 Standard Stain Experiment No. 1 2 3 4 5 6 7 ~;
~; . , Sodium Hydroxide; ~
% Wt. 2 2 2 2.2~ 2.25 2.35 2.35 ~ -Monoethanolamine;
% Wt. 0 .25 5 0 .25 0 1 Stain Removal; % 79.0 69.0 96.6 80.0 99.0 87.0 95.6 ~ ' ~:

1~479~3 ~ :
As evident from Tables VIII and IX, addition oE a small amount of an alkanolamine contributes greatly t~ the cleaning capability of the oven cleaning compositions of the present invention. This is surprising in two respects. For example, :
as shown in Table VIII, Experiments 1 and 2, and Iable IX, Experiments 4 through 7, the addition of a small àmount of an ~:.
alkanolamine to low concentrations of an alkali metal hydroxide :~.
provides a significant increase in stain removal. Also, even though compositions having caustic alone clean very well on ~
standard stains 100 and 105, which are easier to clean, the ~ `, addition of a relatively small amount of alkanolamine improves~
the effect on stain removal.
Stained panels cured at 460F for 1-1/4 hours (112.5 -~
~ ~, degree of difficulty staln) were subjected for six hours to oven cleaning compositions of~the present inventlon comprising varying concentrations of caustic and alkanolamine. These tests ~ ~.
were conducted to determine if alkanolamines had a significant effect on cleaning capabil~ty of low caustic oven cleaning i~
compositions comprising from 0.5 to 4.0% alkali metal hydroxide.

TABLE X ~

Effect on S~ain Removal in Using Compositions of Varying NaOH and Monoethanolamine Concèntrations Experiment No. 1 2 3 4 5 6 Caustic Concen- :~
tration; % Wt. 0.5 0.5 1.0 1.0 1.0 1.0 .-Monoethanolamine Concentration:~
% Wt. 15 20 0 5 9 10 Stain Removal; % 42.0 90.0 4.0 58.0 85.0 92.8 ~ :
.

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~L~479~)3 Table X (Cont'd.) ~ `

Experiment No. 7 8 9 10 11 12 Caustic Concèn-tration: % Wt. 1.0 1.5 1.5 2.0 2.0 2.0 Monoethanolamine Concentration:
% Wt. 20 0 5 0 1 2 Stain Removal; % 96.1 46.0 76.0 79.0 78.0 97.0 Experiment No. 13 14 15 16 17 18 ~ -10 Caustic Concen-tration; % Wt. 2.0 2.6 2.6 3.0 3.0 3.5 Monoethanolamine Concentration;
% Wt. 5 0 1 0 1 0 Stain Removal; % 96.2 88.0 93.9 89.0 95.9 98.4 ~ `

Experiment No. 19 20 21 22 23 24 Caustic Concen-tration: % Wt. 3.5 4.0 4.0 4.0 4.0 4.0 Monoethanolamine Concentration;
% Wt. 5 0 0 2 5 10 Stain Removal; % 99.8 97.1 98.9 99.5 99.5 99.7 ~-;

The results of these experiments demonstrate the inter~

action of alkanolamine and alkali metal hydroxide. For example, even with as low as 1% caustic, the percent of stain removal .
achieved by the addition of 10% of monoethanolamine is greater ~;
than the percent of stain removal with 3% caustic along (see Experiments 6 and 16). Also it is significant that those ov~n cleaning compositions comprising an alkanolamine in addition to alkali metal hydroxide exhlbit superior staln removal compared to those compositions comprising alkali metal hydroxide alone, for eve~ caustic concentration from 0.5 to 4.0%.
It is not intended that the invention be limited by any particular theory as to why addition of an alkanolamine to a low caustic composition provides an oven cleaner as -, '':` ~ '' . .... . . .

7g~3 ~ffective as compositions having high caustic, however, the following discussion may be pertinent. Caus-tic alkali attacks an oven s-tain from the surface and gradually dissolves it with-out penetrating -through the stain. On the other hand, an alkanolamine, in the presence of caustic, reacts quite differently than a caustic alkali. The alkanolamine penetrates through the stain, probably attacking the bond between the stain and the `
surface so as to lift the stain from the oven surface. While caustic alone is effective at high concentrations to remove a common household stain in an adequate perlod of time, the unique combination of an alkanolamine plus a low concentration of caustic is superior in stain removal since this latter oven cleaning composition can penetrate through the stain to lift the stain off the oven surface and allow some caustic to , attack the stain from its under surface. This results in a synergistic cooperation between the caustic alkali and alka-nolamine so that a high concentration of caustic alkali is not required. In order to show that various other alkanolamines are as effective as the monoethanolamine described above, oven cleaning compositions comprising other alkanolamines, listed below in Tables ~I and XII, and 1.5% sodium hydroxide or 2.0 sodium hydroxide were tested on the 112.5 stain. For all experiments, the names of the alkanolamines tested will be abbreviated as follows:
~lonoethanolamine MEA
Triethanolamine TEA
, MonoisopropanQlamine MIPA
N-methylethanolamine N-MEA
Aminoethylethanolamine AEEA . :~
Diglycolamine DiGA

Diisopropanolamine DiIPA :
Triisopropanolamine TriIPA

1~479~3 Mixed isopropanolamine ~made by the Union Carbide Company conSisting of a mixture of 10 to 15 weight %
mono-, 40 to 50 weight ~ di-, and 40 to 50 weight % tri-isopropanol-amine) IPA -~
N,N-diethylethanolamine DiEEA
N,N-dimethylethanolamine DiMEA :
N,N-diisopropylethanolamine DiIPEA
Diethanolamine DiEA
N-methyldiethanolamine MDiEA ;~
N-ethyldiethanolamine EDiEA
,, " ,~
TABLE XI
Effect of Addition of Other Alkanolamines To A Composition of 2.0% Sodium Hydroxide on Removal of 112 5 Stain Test No. 1 2 3 4 5 Alkanolamine -- AEEA MIPA N-MEA DiGA
Alkanolamine;
% Wt. __ 8.52 6.15 6.15 8~6 ` ~
Stain Removal;% 79.0 96.78 84.89 90.89 94.22 ; ,-Test NO. 6 7 8 9 10 ,`~ `
AlkanolamineDiIPA TriIPA IPA DiMEA DiEEA ~ `
: . , Alkanolamine; `,~ `
% Wt. ` 10.8 15.66 12.41 7.3 9.64 Stain Removal; % 89.22 93.67 90.22 76.9 96.9 ' Test NO. 11 12 13 `~`
Al]canolamine MDiEA EDiEA DiPEA
Alkanolamine;
% Wt.9. 75 10. gl 10~.90 Stain Removal; % 59.0 94.0 98.8 TABLE XII
Effect of Addition of Other Alkanolamines To Composition of 1.5% Sodium Hydroxide on Removal of 112.5 Stain `
Test No. 1 2 3 4 S - -Alkanolamine -- AEEA MIPA N-MEA DiGA - ~
-~ .
. -.
18- `;
' 16)4~3 Table XII Con-t'd.
Alkanolamine; % Wt. -- 8.52 6.15 6.15 8.6 Stain Removal; % 47.22 88.0 41.0 71.0 62.0 Test No. 6 7 8 9 10 Alkanolamine DiIPA TriIPA IPA DiMEA DiEEA
Alkanolamine; % Wt. 10.8 15.66 12.41 7.3 9.64 Stain Removal; % 84.0 85.0 89.0 54.5 79.0 Test No. 11 12 13 Alkanolamine MDiEA EDiEA DiPEA
Alkanolamine; % Wt. 9.75 10.91 10.9 Stain Removal; % 32.0 50.0 95.11 It is apparent from Table XI that at the 2% sodium hydroxide level all alkanolamines tested, except for N,N-dimethylethanolamine and N-methyldiethanolamine effect a significant improvement over caustic alone in their cleaning :
capabiltiy. In fact, these oven cleaning compositions com- ; ~
prising 2% sodium hydroxide and the other alkanolamines in ~ `
molar concentrations equal to that of 5% monoethanolamine ;
clean equal to or better than the 3% caustic composition, ~;
.
as shown in Table IV, Experiment 3. B~ decreasing the caustic concentration to 1.5% as shown in Table XII, the cleaning capabiltiy of compositions comprising 1.5% caustic .
alone is reduced to 47.22%. This means that at this lower caustic concentra.tion, the alkanolamines must be more efficient so as to yield a satisfactory level of oven stain .
removal. For example, in T.àble XI, monoisopropanolamine provides good stain removal as compared with the composition comprising 2% caustic alone, but the composition comprising ..
1.5% caustic and monoisopropanolamine does not increase :;~ .
the percent of stain .removal over that of 1.5% caustic alone. ~
When stains of a greater degree of difficulty are ~ .
utilized for testing of these oven cleaning compositions .-.. :. . : ,. ~. : ~ ~ , ~ 7903 such as the 143 s-tain, the contribution of the addition of an alkanolamine becomes even more signiflcant. As shown in Table XIII below, oven cleaning compositions comprising various concentrations of sodium hydroxide and of monoethanol- -amine were tested on the 143 stain.
TABLE XIII

Effect of Compositions of Sodium Hydroxide and Monoethanolamine ~ -on Removal of 143 Stain 10Experiment No. 1 2 3 4 5 Sodium Hydroxide;
~ Wt. 1 2 2 2 3 Monoethanolamine;
~ Wt. ~ 5 10 --Stain Removal; ~ 2.8 23.0 88.0 83.0 70.0 ';"",,~ . ' "
Experiment No. 6 7 8 9 10 11 i~ -Sodium H~droxide;
% Wt. 3.5 3.7 3.7 3.7 4.0 4.0 ~;~

Monoethanolamine- ., % Wt. -- -- 1 5 -- 5 ;~ ~-20Stain Removal; % 80.0 78.0 84.3 96.0 97.1 99.3 ~
-:., ,, ~ .:
It is evident from Table XIII that even when testing this more difficult stain, stain removal is significantly increased by the addition of a small amoun* of an monoethanolamine (compare `~;
Experiments #2 to #3, and #7 to ~9). This is also the case for the other alkanolamines previously tested as shown in the ~;
following Table XIV. In this set of experiments, compositions comprising 3.7~ sodium hydroxide and the other alkanolamines were applled to the 143 stain.

TABLE XIV
,:
Effect of Addition of Alkanolamines and 3.7~ 5Odium H~droxide on Rémoval o 143 Stain -~
~, Test No. 1 2 3 4 5 6 Alkanolamine -- AEEA MIPA N-MEA DiGA DiIPA

-~047~Q3 Table XIV Cont'd.
Alkanolamine; % Wt. -- 8.52 6.15 6.15 8.60 10.8 Stain Removal; ~ 78.0 98.9 97.1 98.0 82.0 95.4 Test No. 7 8 9 10 Alkanolamine TriIPA IPA DiMEA DiEEA
Alkanolamine; ~ 15.66 12.41 7.3 9.64 Stain Removal; ~ 89.4 97.1 96.7 94.7 Test No. 11 12 13 Alkanolamine MDiEA EDiEA DIPEA ~ ~
Alkanolamine; ~ 9.75 10.91 10.9 :-Stain Removal; % 90.7 90.9 99.3 In comparing the oven cleaning composition comprising 3.7% -caustic alone., which removed 78% of the 143 stain, with the oven cleaning compositions comprising 3.7% caustic and an ~ .
alkanolamine, there is a significant improvement in cleaning ~.
with compositions comprising the alkali metal hydroxide~
.
alkanolamine combination. The weight percentages of the .
alkanolamines listed in Ta.bles XI, XII, and XIV are such that ~;
the alkanolamines are equimolar.
Effect of Addition of MEA to Composition of 2.09% Lithium Hydroxide On Removal of 112.5 Stain :~
Experiment No. 1 2 - .
Monoethanolamine, ~ -- 5 ;~
Stain Rè~oval; % 83.0 98.4 Since oven cleaning compositions comprising a caustic alkali and triethanolamine have been disclosed in the prior art, .
experiments were conducted on the various standard stains with various concentrations of both sodium hydroxide and tri- : .
ethanolamine to determine the effectiveness of this particular alkanolamine in oven cleaning compositions having low caustic.
' 1~47~3 ` ~
TABLE XVI
Evalua-tion of Compositions having TEA to Compositions having MEA in % Stain Removal Experiment No. 1 2 3 4 5 6 Standard Stain 112.5 112.5 112.5 112.5 112.5 112.5 Sodium Hydroxide;
% Wt. 0.5 0.5 0.5 1.5 1.5 1.5 Alkanolamine MEA MEA TEA -- MEA TEA
Alkanolamine; % Wt. 15 20 15 -- 5 12.21 - ;
Stain Removal; % 42.0 90.0 41.7 46.0 76.0 16.0 -~
Experiment No. 7 8 9 10 11 12 Standard Stain 112.5 112.5 112.5 112.5 112.5 112.5 '`~
Sodium Hydroxide;
~ Wt. 2 ~2 2 3 3 3 Alkanolamine -- MEA TEA ~- MEA TEA ;
. ~ . .- :
Alkanolamine; % Wt. -- 5 12.21 -- 1 12.21 Stain Re~oval; % 79.0 92.1 72.3 89.0 95.9 86.0 Experiment No. 13 14 15 16 17 18 Standard Stain 112.5 112.5 112.5 143 143 143 Sodium Uydroxide;
% Wt. 3.5 3.5 3-5 3-7 3-7 3-7 ,~
Alkanolamine -- MEA TEA -- MEA TEA
- .
Alkanolamine; % Wt. -- 5 12.21 -- 5 12.21 Stain Removal; % 98.4 99.8 93.1 78.0 96.0 95.0 Experiment No. 19 20 21 Standard Stain 143 143 143 Sodium Hydroxide;
% Wt 4 4 4 Alkanolamine -- MEA TEA ~ , ,. ~
Alkanolamine; % Wt. -- 5 12.21 Stain Removal; ~ 97.1 99.5 92.8 '' , ': ~ ' ' " ': , . . :

~347903 It is evident from Table XVI that triethanolamine does not increase the cleaning capabiltiy of compositions com prising from 0.5 to 4.0% ~austic. Further, triethanolamine has a deleterious effect on the composi-tions tested in Experiment 6, 9, 12, 15 and 21 because these compositions exhibit less stain removal than those compositions having caustic alone.
Some oven cleaning compositions have been prepared utilizing the ingredients of the present invention as follows:

TABLE XVII

% by % by % by % by Ingredients Wt. (A) Wt. (B) Wt. (C) Wt. (D) Water (DI) 81.0076.14 75.63 83.40 Bentonite 2.43 2.43 2.41 2.50 ~ -50% Aqueous NaOH 3.93 3.97 3.85 4.00 Monoethanolamine 4.86 9.72 9.65 5.00 ~-Lauryl Alcohol0.87 0.87 0.87 0.90 Coconut oil fatty acid 0.970.97 0.96 1.00 Perfume 0.19 0.19 0.19 0.20 Propellant 5.75 5.75 6.44 3.00 ` ;~

Examples A and B in Table XVII are preferred embodiments of this invention.
In a preferred range of ingredients the oven cleaning compositions of the present invention comprise, by weight, from about 1.5% to about 3.7% of an alkali metal hydroxide; from about 3% to 15% of an alkanolamine selected from the group consisting of: monoethanolamine, monoisopropanolamine, N-methylethanolamine, aminoethylethanolamine, diglycolamine, diisopropanolamine, triisopropanolamine, mixed isopropanolamine, N,N-diethylethanolamine, N,N-diisopropylethanolamine, diethanol- ;~
amine, and N-ethyldiethanolamine~ and up to about 95.5% of water. ~`~
-~:
- 23 - ~

r~

:ILlt)47903 Another preferred embodiment of the oven cleaning compositions of the present invention comprises, by weight, ;~
about 2.0% of sodium hydroxide; about 5.0% of monoethanolamine;
about 2~5% bentonite; about 1.0% of a coconut oil fatty acid;
about 1.5% of an isobutane-n-butane propellant and up to about ;
88.0% water.
Another preferred embodiment of the oven cleaning ~ ~
compositions of the present invention comprises, by weight, ~ -about 2.0% of sodium hydroxide; about 10.0% of monoethanolamine; -~ ;
about 2.5% bentonite; àbout 1.0% of a coconut fatty acid; ~ ~
.:. .
about 1.5% of an isobutane-n-butane propellant and up to about ;

83.0% water.

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Claims (27)

The embodiments of the invention in which an exclu-sive property or privilege is claimed are defined as follows:

1. An oven cleaning composition comprising:
a. from about 0.5% to about 4.0% by weight, of an alkali metal hydroxide;
b. from about 1.0% to about 20.0% by weight, of an alkanolamine selected from the group consisting of:
monoethanolamine, monoisopropanolamine, N-methyl-ethanolamine, aminoethylethanolamine, diglycolamine, diisopropanolamine, mixed isopropanolamine, N,N-diethylethanolamine, dimethylethanolamine, N,N-diisopropylethanolamine, diethanolamine, and N-ethyldiethanolamine; and up to about 98.5% by weight of water.

2. An oven cleaning composition comprising:
a. from about 0.5% to about 4.0% by weight, of an alkali metal hydroxide;
b. from about 1.0% to about 20.0% by weight, of an alkanolamine selected from the group consisting of:
monoethanolamine, N-methylethanolamine, aminoethyl-ethanolamine, diglycolamine, diisopropanolamine, mixed isopropanolamine, N,N-diethylethanolamine, dimethylethanolamine, and N,N-diisopropylethanolamine;
and up to about 98.5% by weight of water.

3. A composition according to Claim 2 wherein said hydroxide is sodium hydroxide.

4. A composition according to Claim 2 wherein said hydroxide is potassium hydroxide.

5. A composition according to Claim 2 wherein said hydroxide is lithium hydroxide.

6. A composition according to Claim 2 wherein said alkanolamine is monoethanolamine.

7. A composition according to Claim 2 wherein said alkanolamine is aminoethylethanolamine.

8. A composition according to Claim 2 wherein said alkanolamine is diglycolamine.

9. A composition according to Claim 2 wherein said hydroxide is sodium hydroxide and said alkanolamine is mono-ethanolamine.

10. A composition according to Claim 2 wherein said hydroxide is sodium hydroxide and said alkanolamine is amino-ethylethanolamine.

11. A composition according to Claim 2 wherein said hydroxide is sodium hydroxide and said alkanolamine is diglycolamine.

12. An aqueous oven cleaning composition comprising:
a. from about 1.5% to about 3.7% by weight, of an alkali metal hydroxide;

b. from about 3.0% to about 15.0% by weight, of an alkanolamine selected from the group consisting of:
monoethanolamine, monoisopropanolamine, M-methyl-ethanolamine, aminoethylethanolamine, diglycolamine, diisopropanolamine, mixed isopropanolamine, N,N-diethylethanolamine, N,N-diisopropylethanolamine, diethanolamine, and N-ethyldiethanolamine; and up to about 95.5% by weight water.

13. A composition according to Claim 12 wherein said hydroxide is sodium hydroxide.

14. A composition according to Claim 12 wherein said hydroxide is potassium hydroxide.

15. A composition according to Claim 12 wherein said hydroxide is lithium hydroxide.

16. A composition according to Claim 12 wherein said alkanolamine is monoethanolamine.

17. A composition according to Claim 12 wherein said alkanolamine is aminoethylethanolamine.

18. A composition according to Claim 12 wherein said alkanolamine is diglycolamine.

19. A composition according to Claim 12 wherein said hydroxide is sodium hydroxide and said alkanolamine is mono-ethanolamine.

A composition according to Claim 12 wherein said hydroxide is sodium hydroxide and said alkanolamine is amino-ethylethanolamine.

21. A composition according to Claim 12 wherein said hydroxide is sodium hydroxide and said alkanolamine is diglycolamine.

22. An aerosol oven cleaning composition consisting essentially of:
a. about 2.0% of an alkali metal hydroxide;
b. about 5.0% of an alkanolamine selected from the group consisting of monoethanolamine, monoisopropanol-amine, N-methylethanolamine, aminoethylethanolamine, diglycolamine, diisopropanolamine, mixed isopropanol-amine, N,N-diethylethanolamine, N,N-diisopropyl-ethanolamine, diethanolamine and N-ethyldiethanolamine;
c. about 2.5% thickener;
d. about 1.0% solubilizer;
e. about 1.5% of propellant; and f. up to about 88% water; by weight of said composition.

23. An aerosol oven cleaning composition consisting essentially of:
a. about 2.0% of an alkali metal hydroxide;
b. about 10.0% of an alkanolamine selected from the group consisting of monoethanolamine, monoisopropanol-amine, N-methylethanolamine, aminoethylethanolamine, diglycolamine, diisopropanolamine, mixed isopropanol-amine, N,N-diethylethanolamine, N,N-diisopropylethanol-amine, diethanolamine and N-ethyldiethanolamine;

c. about 2.5% thickener;
d. about 1.0% solubilizer;
e. about 1.5% of propellant; and f. up to about 83% water; by weight of said composition.

24. An aerosol oven cleaning composition consisting essentially of:
a. about 2.0% of an alkali metal hydroxide;
b. about 5.0% of monoethanolamine;
c. about 2.5% bentonite;
d. about 1.0% coconut oil fatty acid;
e. about 1.5% of an isobutane-n-butane propellant; and f. up to about 88% water; by weight of said composition.

25. An aerosol cleaning composition consisting essentially of:
a. about 2.0% of an alkali metal hydroxide;
b. about 10.0% of monoethanolamine;
c. about 2.5% bentonite;
d. about 1.0% coconut oil fatty acid;
e. about 1.5% of an isobutane-n-butane propellant; and f. up to about 83% water; by weight of said composition.

26. An aerosol oven cleaning composition consisting essentially of, by weight:

27. An aerosol oven cleaning composition consisting essentially of, by weight: