[0001] The removal of undesirable organic matter from various hard surfaces such as metal,
ceramics, baked enamel has received a great deal of study. The organic matter referred
to herein occurs for example, as soil in ovens, on baking pans and barbecue racks,
as finishes, coatings, paints and the like.
[0002] Oven soil which contains baked-on fat and other food ingredients is usually cleaned
by applying to the soil thickened solutions of one of the caustic metal alkalis, either
sodium or potassium hydroxide. These materials react with and hydrolyze the fats,
converting them at least partially into their sodium or potassium salts, which are
water soluble. These water soluble soaps are then washed out of the oven with a wet
rag or sponge. Commercial products of this type usually contain up to 5% of the metal
hydroxide together with other components such as solvents, wetting agents, etc., which
contribute to the efficacy of the product.
[0003] Products of the type described, although efficient in their cleaning ability, suffer
a number of major disadvantages. They are corrosive and, hence, are severely hazardous
to the eyes and skin. Also, the residue after cleaning is slimy due to the saponification
reaction and unreacted cleaner, making the task of removing the residue both messy
and burdensome.
[0004] Non-caustic compositions for removal of oven soil are described in U.S. Patent Nos.
4,236,935; 4,193,886; 4,116,848; and 3,808,051. However, all appear to describe a
saponification reaction with the formation of water soluble or dispersible soaps.
The residue from the reaction would be washed out with a wet or damp sponge. Heating
the composition on the soil to a temperature of at least 250
0F. is also necessary for cleaning to occur.
[0005] U.S. Patent 3,881,948 also describes a non-caustic composition, based on a polyhydric
alcohol and an alkaline acting catalyst. Here the reaction also forms water soluble
or water dispersible compounds which must be washed out of the oven. Heating the composition
on the soil to a temperature of at least 250
0F. is necessary for cleaning to occur.
[0006] For the removal of finishes, coatings, paints, and the like, aqueous solutions of
alkali metal hydroxides have been used to saponify the fatty acid constituents of
the bonding component of the composition, thereby loosening and facilitating the removal
thereof. Such products have similar disadvantages to the oven cleaner compositions
based on alkali metal hydroxides in that they are corrosive to the eye and skin. These
"stripping" compositions generally contain other additives such as water miscible
solvents, accelerators, surfactants and thickeners, to aid product performance. For
example, U.S. Patent No. 3,819,529 discloses a paint stripping composition consisting
essentially of an inorganic alkaline material selected from the group consisting of
alkali metal hydroxides, carbonates, silicates, and phosphates and an alkyl or aryl
(having not more than six (6) carbon atoms) substituted imidazole. The substituted
imidazole is described as an accelerator. Although the disclosure of this patent is
confusing as to necessary components which comprise the stripping composition, it
is clear that the substituted imidazole is not the stripping agent, but only acts
to increase the rate of attack. It is the strong alkali metal compounds which operate
to loosen the paint from the surface.
[0007] It is, accordingly, an object of the invention to provide a novel method and novel
compositions for the removal of organic matter from surfaces.
[0008] It is a further object of the invention to provide novel compositions which are non-caustic,
non-corrosive, and essentially non-irritating to the eyes and skin.
[0009] It is another object of the invention to provide a novel method and novel compositions
which give a relatively dry residue which may be physically removed from the surface
by wiping or brushing.
[0010] It is yet another object of the invention to provide such novel compositions which
are useful in a variety of forms, such as paste, aerosol, and pump spray.
[0011] These and other objects and advantages of the instant invention will become apparent
from the following detailed description.
[0012] The novel method of the invention comprises applying to the undesirable organic matter
an amount of imidazole, pyrazole or an alkyl or aryl substituted imidazole or pyrazole,
for a time sufficient to loosen the organic matter from the surface, and removing
the loosened organic matter from the surface. Compositions containing the imidazole,
pyrazole, substituted imidazole or substituted pyrazole as the active ingredient are
also within the scope of the invention. Obviously, two or more of these compounds
may be used in combination in the method or compositions of the present invention.
Compounds falling within the scope of an alkyl or aryl substituted imidazole include,
inter alia, 1-methylimidazole, 2-methylimidazole, 4-methylimidazole, 1,2-dimethylimidazole,
2-ethylimidazole, 2-isopropylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole,
4-phenylimidazole, benzimidazole and the like. Compounds falling within the scope
of an alkyl or aryl substituted pyrazole include 3-methylpyrazole, 3,5-dimethylpyrazole
and the like.
[0013] The imidazole, pyrazole, alkyl or aryl substit-. uted imidazole, or alkyl or aryl
substituted pyrazole is effective by itself, without the need for a carrier, or additional
ingredients, such as the alkali metal compounds required in U.S. Patent No. 3,819,529,
supra, provided only that the compound be in liquid form at use temperature.
[0014] Obviously, it is also desirable that the imidazole, pyrazole, substituted imidazole
or substituted pyrazole be maintained in contact with the soiled substrate to effectuate
maximum cleaning. Accordingly, thickened solutions or suspensions of the compound
which may be applied as a paste or via pump spray or aerosol systems would be preferred
for many applications, such as in oven cleaning, where the compound must be maintained
on an overhead and/or vertical surface. Preparation of these aerosol, pump spray and
paste compositions are within the ordinary skill in the art.
[0015] When used with a carrier (or carrier plus additional ingredients), the concentration
of the imidazole, pyrazole, substituted imidazole or substituted pyrazole may vary
over a wide range - from as little as about 1%, by weight, to as much as about 99%,
by weight. Preferably, the imidazole, pyrazole, substituted imidazole or substituted
pyrazole will comprise about 5 to 25% by weight, of the total composition. Aqueous
carriers, or water and water miscible organic solvent mixtures are preferred. It has
been found that the aryl substituted and higher alkyl (chain length greater than two
(2) carbons) substituted imidazoles and pyrazoles are not very soluble in water and,
accordingly, the use of a co-solvent in a composition containing any of these compounds
and water may be desirable. Alternatively, a non-aqueous carrier may be used. When
the particular compound used is not liquid at a desired use temperature (such as room
temperature), these carriers may be used to solubilize the compound, and accordingly
the carrier system may be routinely chosen by one skilled in the art taking into consideration
the solubility of the particular compound being used in various solvent mixtures,
and the intended use. Alternatively, of course, the compound may be applied as a dispersion
thereof in a carrier, or in a dry state at, for example, room temperature and the
system heated to a temperature sufficient to cause the compound to be solubilized
in the carrier or melt, thereby rendering the same "active".
[0016] When a thickening agent is desirably used with the compound, for example when the
organic matter to be removed is on a non-horizontal surface, any such agent, or mixture
of two or more thereof, which is compatible with the imidazole, pyrazole or substituted
imidazole or pyrazole (and with other ingredients in a formulation, if a formulation
is used) may be used. Useful organic thickening agents include starch, sodium carboxymethylcellulose,
hydroxyethyl cellulose, methocel, and water-soluble polymers such as carboxy vinyl
polymer (Carbopols from B. F. Goodrich Chemical Company) and most preferred are Xanthan
gums such as Kel- trol
o, made by Kelco Company. Inorganic colloidal materials, such as Veegum (magnesium
aluminum silicates manufactured by R. T. Vanderbilt), are also effective. When used,
the thickening agent will typically comprise about 0.1 to 10%, by weight, of the composition,
although more or less may be used.
[0017] It may also be preferable in certain instances to have present as a component of
the composition of the present invention a minor amount of surface active agent which
will cause the composition to spread evenly over the surface from which the undesirable
organic matter is to be removed, or to form a foam. The surface active agents can
be any of those commonly known and used as such. An extensive list of such agents
appears in the publication McCutcheon's Detergents & Emulsifiers, 1982 Annual. The
agents can be anionic, cationic, nonionic, or amphoteric and should be compatible
with the other ingredients and impart the desired surface active properties. When
used, the surface active agent will typically comprise about 0.01 to 0.8%, by weight,
of the composition, although more or less may be used.
[0018] Examples of anionic surfactants include (a) carboxylic acids such as soaps of straight
chain naturally occurring fatty acids, chain-substituted derivatives of fatty acids,
branched-chain and odd-carbon fatty acids, acids from paraffin oxidation, and carboxylic
acids with intermediate linkages; (b) sulfuric esters such as sodium lauryl sulfate,
tallow alcohol sulfates and coconut alcohol sulfates; and (c) alkylaryl sulfonates
such as sodium dodecylbenzene sulfonate, sodium tridecyl benzene sulfonate, and sodium
dodecyl diphenyloxide disulphonate.
[0019] Examples of cationic surfactants include (a) non- quaternary nitrogen bases such
as amines without intermediate linkages; and (b) quaternary nitrogen bases of the
formula:
wherein R is a straight-chain alkyl of 12 to 19 carbon atoms, wherein a, b, and c
are methyl, ethyl, or benzyl (usually not more than one benzyl group being present),
and wherein X is halide such as chloride, bromide or iodide, methylsulfate or ethylsulfate
and quaternary ammonium salts such as Hyamine 10X (diisobutylcresoxy ethoxyethyl dimethylbenzyl
ammonium chloride monohydrate).
[0020] Examples of nonionic surfactants include polyethyleneoxy ethers of alkylphenols,
alkanols, esters and polyethyleneoxy compounds with amide links.
[0021] In one embodiment of the composition of the invention, a water insoluble, finely
divided material is suspended therein to aid in removing the organic matter and residual
composition after the organic matter has been loosened from the surface. Although
the addition of these materials assist in the removal of varnish, finishes, coatings,
paints, and the like, it has been found to be particularly beneficial for the removal
of oven soil. In oven cleaning applications, the addition of these materials has been
found to contribute to the ease of removal of the organic matter (and residual composition)
from the oven surface after the cleaning cycle by wiping with a dry paper towel, a
brush or the like. When used, the amount of such finely divided material present in
the composition of the present invention typically ranges from about 1 to 25%, by
weight, of the composition, preferably about 2 to 10%, although more or less may be
used. Examples of such finely divided inorganic material include calcium carbonate,
magnesium carbonate, magnesium hydroxide, silica, feldspar, clay and talc.
[0022] In another embodiment of the composition of the present invention, a water soluble
salt of a strong base and a strong acid is added to the composition containing the
imidazole, pyrazole, or substituted imidazole or pyrazole. The addition of the salt
has been found to improve the soil loosening activity of the composition and also
contributes to the ease of removal of the organic matter and residual composition.
Here again, the benefit has been found to be particularly pronounced in oven cleaning
applications. When used, the amount of the salt typically ranges from about 1% to
25% by weight, of the composition depending, of course, upon the solubility of the
compound being used, and is preferably about 1% to 10%, by weight, of the composition,
although more or less may be used. Examples of such water soluble salts include sodium
chloride, potassium chloride, sodium sulfate, and potassium sulfate.
[0023] Other additives which are typically used in compositions for removal of organic matter
may also be used in the compositions of the present invention, provided, of course,
that they are compatible therewith. Exemplary of such other additives are humectants,
anti-foaming agents, dispersants and the like.
[0024] It is an advantage of the method and compositions of the present invention that the
same may be employed at room temperature, or at elevated temperatures when speedier
cleaning is desired or necessary, such as in oven cleaning applications.
[0025] A preferred composition of the present invention for oven cleaning applications is
the following:
[0026] Preferred compositions of the present invention for other organic coatings, such
as polyurethanes, alkyd resins, vinyl resins, and acrylic resins, removal applications
are the following:
[0027] ..The present invention is turther illustrated by the following examples. However,
it is to be understood that the invention is not to be deemed in any way limited by
these examples. All parts and percentages are by weight unless indicated to the contrary.
Example 1
[0028] A fifty percent chicken fat, fifty percent lard soil composition was baked on a stainless
steel plate at 500
0F. for 30 minutes. The baking converted the chicken fat and lard into a hard, brown,
varnish-like coating, similar in composition and appearance to the fatty soil found
in ovens. After cooling, imidazole was applied to the soil, and the plate heated to
300°F. for 60 minutes. The imidazole melted on the soil. During the heating cycle,
it was observed that the soil wrinkled and broke away from the metal surface. Upon
cooling, the imidazole resolidified with the wrinkled soil, and the residue was readily
brushed from the metal surface.
Example 2
[0029] A forty percent solution of imidazole in water was applied to a stainless steel plate
having the baked-on soil composition of Example 1 thereon, and heated to 300°F. for
one hour. Results were similar to those achieved in Example 1.
Examples 3 and 4
[0030] Twenty-five and ten percent solutions of imidazole in water were each separately
applied to stainless steel plates having the baked-on soil of Example 1 thereon, and
heated to 225
0F., 375
0F. and 525
0F. for 60 minutes. Best loosening of the soil occurred at 225
0F. for both solutions, it being theorized that at the higher temperatures some of
the imidazole was lost due to evaporation, thereby reducing the cleaning efficacy
thereof.
Examples 5 and 6
[0031] The following formulations were prepared:
[0032] The formulations were applied to soiled stainless steel plates having the baked-on
soil composition of Example 1 thereon, and heated for one hour at 225
0F., 375
0F., and 525
0F. As in Examples 3 and 4, best loosening of the soil occurred at 225°F. At this temperature,
both formulations gave excellent removal of the soil. The ease of removal of the residue
by physical means such as wiping with sponge, paper towel, scrubbing pad, etc., or
by brushing was improved as compared to formulations not containing calcium carbonate.
Examples 7 and 8
[0033] A fifty percent chicken fat, fifty percent lard soil composition was baked onto six
(6) porcelain enameled test trays at 500°F. for 30 minutes.
[0034] The following formulations were prepared:
[0035] Each of the formulations was applied (30 g/1000 cm
2) to three (3) of the soiled trays as follows:
Condition A: Applied at ambient temperature (about 68 to 77°F.) and left for. sixteen
(16) hours without heat, in a household oven;
Condition B: Applied at ambient temperature, then heated in oven at 2250F. for fifteen (15) minutes, then allowed to cool;
Condition C: Applied to warm (200°F) soiled tray, then allowed to cool gradually in
oven.
[0036] Very good (at least 90%) soil removal was obtained with the formulation containing
ten (10) percent imidazole at all three cleaning conditions. The formulation residue
could also be easily removed from the surface by brushing. Good (60 to 90%) removal
was obtained with the formulation containing five (5) percent imidazole. Ease of removal
of the residue was also good.
Examples 9 and 10
[0037] The following formulations were prepared:
[0038] The formulations were applied to soiled porcelain enameled test trays, prepared as
described in Examples 7 and 8, and evaluated using the three (3) test condition described
in Examples 7 and 8 for both soil removal and ease of removing the residue by brushing.
[0039] Very good soil removal and ease of residue removal was obtained with the formulation
containing the calcium carbonate. However, even better soil removal was obtained with
the formulation containing the potassium sulfate and calcium carbonate. The ease of
brushing the residue off the tray was also improved. These test results were obtained
at all three test conditions.
Example 11
[0040] The following base formulation was prepared:
[0041] There was then added to this base formulaton varying amounts of imidazole and substituted
imidazoles as shown in Table 1, and water to total one hundred (100) percent.
[0042] The various formulations were applied (30 g/1000 cm2) to soiled porcelain enameled
test trays, prepared as described in Examples 7 and 8, and evaluated using the three
test conditions described in Examples 7 and 8.
[0043] At the end of each treatment, the soil plus the residual formulation was brushed
from each treated plate followed by wiping with a damp sponge. The overall degree
of cleaning was evaluated according to the following scale: VG - Very good - at least
90% of treated area cleaned. G - Good - 60 - 90% of treated area cleaned.
[0044] F - Fair - 25 - 60% of treated area cleaned.
[0045] P - Poor - some cleaning occurred, but less than 25% of treated area cleaned.
[0046]
Example 12
[0047] A soil composition containing 120g. ground beef, 58g. cheddar cheese, 120ml. milk,
110g. sugar, 120ml. cherry juice, 19g. tapioca, 1 egg, 15g. flour and 120ml. tomato
juice was prepared by mixing with a hand mixer (low speed) for 3 minutes. The soil
was baked onto a porcelain enameled test tray at 450
0F. for 60 minutes. After cooling, imidazole was applied to the soil, and the plate
heated to 300°F. for 60 minutes. The results obtained were similar to those achieved
in Example 1.
Examples 13 to 17
[0048] The procedure of Example 1 is repeated, except that 2-phenylimidazole, 4-phenylimidazole,
benzimidazole, pyrazole and 3-methylpyrazole are each separately substituted for imidazole.
At least fair (25-60%) soil removal is accomplished in each instance.
Examples 18 and 19
[0049] The following two (2) formulations were prepared:
[0050] Both formulations were tested for their ability to remove a variety of organic coatings
from surfaces as follows:
The following twelve (12) coatings were each brushed or sprayed on one (1) wood and
one (1) metal surface test panel according to label directions. The twenty-four (24)
test panels were then dried overnight, and aged for eight (8) hours at 1000C. in an air circulation oven.
Coatings:
[0051]
1. McCloskeyTM - Clear Varnish # 0092 Gloss
2. McCloskeyTM - Gloss Polyurethane # 1195
3. Rust-OleumTM - Gloss White # 7792
4. SearsTM - Interior/Exterior White Enamel # 30-69954
5. SearsTM - Easy Living Flat Interior Latex # 30-91444
6. SearsTM - Easy Living Semi-Gloss Interior Latex # 30-78114
7. SearsTM - Gloss Enamel (White) # 30-69324
8. SearsTM - High Gloss Enamel (Cherry Red) # 30-67524
9. KrylonTM - Spray Enamel (Cherry Red) # 2101
10. KrylonTM - Spray Enamel (Flat Black) # 1602
11. Dupli-ColorTM - Automotive Touch Up Paint #DS-GM-301
12. RevlonTM - Nail Enamel
[0052] To 25cm
2 of each of the so prepared test panels was then uniformly applied about 5 grams of
each fomulation, above, at room temperature (about 2l
oC.).
[0053] For coatings 1 through 10, wrinkles began appearing in the'tested areas after about
1 hour. The entire treated area wrinkled within about 4 hours, and the treated area
was easily wiped clean.
[0054] For coating 11, bubbles developed in the treated area, and about 25% of the treated
area was brushed clean.
[0055] For coating 12, after two (2) hours, all polish on the treated area was easily removed
by washing with water.
Examples 20 to 23
[0056] The procedure of Examples 18 and 19 is repeated, except that 3-methylpyrazole and
pyrazole are separately substituted for the imidazole. Substantial removal of the
twelve (12) coatings from both wood and metal surface test panels is accomplished.
1. A method for facilitating the removal of undesirable organic matter from a surface
which comprises contacting said organic matter with a substantially loosening effective
amount of a compound selected from imidazole, pyrazole, an alkyl or aryl substituted
imidazole, an alkyl or aryl substituted pyrazole, or a mixture of two or more thereof,
in liquid form, for a time sufficient to effect a substantial loosening of said organic
matter.
2. A method for facilitating the removal of an undesirable organic matter from a surface
which comprises contacting said organic matter with a substantially loosening effective
amount of a compound selected from imidazole, pyrazole, an alkyl or aryl substituted
imidazole, an alkyl or aryl substituted pyrazole, or a mixture of two or more thereof,
in dry, dispersion, or part solution-part dispersion form and heating the system to
a temperature at which the compound is rendered liquid, for a time sufficient to effect
a substantial loosening of said organic matter.
3. The method according to Claim 1 wherein the compound is imidazole, 2-methylimidazole,
4-methylimidazole, 1,2-dimethylimidazole, 2-ethylimidazole, 2-ethyl-4-methylimidazole,
1-isopropylimidazole, or a mixture of two or more thereof.
4. The method according to Claim 1 wherein the compound is imidazole.
5. The method according to Claim 1 wherein the organic matter is food soil and the
surface is an oven surface.
6. The method according to Claim 4 wherein the organic matter is food soil and the
surface is an oven surface.
7. A non-caustic composition for facilitating the removal of undesirable organic matter
from a surface which comprises (a) a substantially loosening effective amount of a
compound selected from imidazole, pyrazole, an alkyl or aryl substituted imidazole,
an alkyl or aryl substituted pyrazole, or a mixture of two or more thereof and (b)
a carrier.
8. The composition of Claim 7 further comprising (c) a thickening agent and, optionally,
one or more of (d) a surfactant, (e) a finely divided inorganic material, and (f)
a water soluble salt of a strong acid and a strong base.
9. The composition of Claim 8 wherein (c) is selected from the group consisting of
starch, sodium carboxymethyl cellulose, hydroxymethyl cellulose, methocel, carboxy
vinyl polymers, Xanthan gum, magnesium aluminum silicates, and mixtures of two or
more thereof, (e) is selected from the group consisting of calcium carbonate, magnesium
carbonate, magnesium hydroxide, silica, feldspar, clay, talc and mixtures of two or
more thereof, and (f) is selected from the group consisting of sodium chloride, potassium
chloride, sodium sulfate, potassium sulfate and mixtures of-two or more thereof.
10. The composition according to Claim 9 wherein the compound is imidazole.