Note: Descriptions are shown in the official language in which they were submitted.
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The present invention relates to an improved oven
cleaner and to a method for removing baked on fats and
greases from cooking surfaces.
Oven cleaners are compositions of matter used to remove
baked on fats and greases from cooking surfaces. Such
compositions are commonly used for cleaning ovens as the name
implies but may also be used to clean other cooking surfaces
on which there has been a build up of baked on fats and
greases. Such surfaces include fry pans, kitchenware,
barbecue equipment, cooking utensils and the like. These
surfaces may be of bare metal, metal coated as with baked
enamel, glazed stoneware, porcelain, glass or the like.
Conventional oven cleaners are based on caustic soda.
It has generally been considered necessary to use a caustic
alkali in order to efectively saponify the fats in the baked
on material in order to enable its removal. A ~ew oven
cleaners have been based on solvents, acetate salts, amines
or ammonia. The known caustic based systems suffer from the
disadvantage o~ being quite hazardous and/or require the
consumer to wear gloves during usage. These known
caustic-based systems are required to carry poisons schedule
labelling and warning statements. The systems based on
acetate salts have the disadvantage that they require
temperatures of 250C or above to activate them.
It has been proposed in the past to individually add
organic solvents and inorganic builder salts to oven cleaning
compositions based on alkali or nitrogen containing active
cleaning ingredients. Such additions are for instance
disclosed in U.S. Patent Specifications 3,829,387; 3,813,343;
and 3,658,711. It has also been known to use aqueous
solutions of alkali metal salts to form non-stick coatings on
ovens; see U.K. Patent Specifications 2,019,876 and
1,523,491 and Australian Patent Specification 453,537. It
has not previously been proposed, however, to use the two
abovementioned types of ingredients together. It has also
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not been previously recognised that these two types of
ingredients, which each has only a mild cleaning action on
its own, can be combined together to provide a highly
e~fective oven cleaner while avoiding many of the
disadvantages of the known oven cleaners.
The present invention consists in an oven cleaner
containing as acti.ve ingredients an effective amount of an
alkali metal bicarbonate, sesquicarbonate or carbonate or a
mixture thereof and a polyhydric alcohol which is liquid and
substantially non-volatile at the desired cleaning
temperature and in which the alkali metal salt is soluble at
that temperature.
The present invention further consists in applying the
oven cleaner according to this invention to a cooking surface
carrying baked on fats or g;reases, heating the cooking
surface to at least 125C, and preferably from 125 to
250C, for a period of at least five minutes and washing
andJor wiping the saponified fats or greases from the cooking
surface.
The oven cleaner according tG the present invention may
have a pH as low as 9 or less which allows its use without
rubber gloves and like protective clothing. These oven
cleaners also have the advantage that surfaces of stainless
steel, aluminium, and some other metals will be left with a
shiny surface after cleaning rather than being left with a
dull, oxidised, surface as is the case with many of the prior
art oven cleaning compositions.
The non-caustic alkali metal salt is most preferably
sodium or potassium bicarbonate. Other alkali metal salts
which can be advantageously used include sodium or potassium
sesquicarbonate, and sodium or potassium carbonate. The
alkaline salt preferably comprise from 0.5 to 20% by weight
of the product and most preferably 2 to 20% by weight.
The pH of the product is preferably below 11 and more
preferably below 10 and most preferably 9 or below.
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The po]yhydric alcohol used in the present invention
preferably have the general formula:
CH20H (CHO~) n CH2O~ where n = 0, 1, 2, 3 or 4.
The liq~id is most preferably glycerol or includes glycerol.
Other compounds in this group which may be used include
mannitol, ethylene glycol and sorbitol. When the salt is a
potassium salt the polyhydric alcohol ma~ with equal
effectiveness be an alcohol falling outside the above general
formula. This is blelieved to be due to the higher solubility
of the potassium salts in the polyols as compared with the
corresponding sodium salt. Plolyhydric alcohols which work
efficiently ~ith the potassium salts include various grades
of propylene glycol, diethylene glycol, polyeth~lene glycol,
dipropylene glycol, polypropylene glycol, triethylene glycol,
and 1,2,6 hexanetriol. The p~olyhydric alcohol preferably
comprises from 1 to 50% by weight of the product.
The oven cleaner according to this invention preferably
includes water. The water is preferably present in an amount
of at least 35% by weight.
The oven cleaner is preferably water based and
preferably contains a thickener to prevent it running off
vertical surfaces. Other ingredients may include a
surfactant or soap, a fragrance, a pigment marker and a
propellant.
The oven cleaner according to this invention may be
applied in any suitable manner. These include an aerosol, a
trigger or pump spray, a brush or pad.
In carrying out the method according to this invention
the oven cleaner is preferably applied to a surface to be
cleaned and heated to a temperature of from 125C to
250C for a time of from 5 minutes to 2 hours.
It is believed that oven cleaners according to this
invention are effective, despite their limited alkalinity and
the evaporation of the water from the cleaner, due to the
continued action of the alkaline salt dissolved in the
_ 5 _ ~ 21 1 6'~4
non-volatile polyhydric alcohol. The alkaline salt is
maintained in a condition in which it is available for
reaction with the baked on fats and greases at the required
elevated temperature by being dissolved in the polyhydric
alcohol. For this reason the polyhydric alcohol is required
to be substantially non-volatile at the cleaning temperature.
Hereinafter given by way of example are preferred
embod~ments of t;he present invention.
Test surfaces were prepared by baking smeared dripping
onto white vitreous enamel metal plates for 1 1/2 hours at
250 C. The baked-on dripping could not be removed at all
by washing or wiping without a scourer.
Cleaners consisting of the formulations given below were
applied to the test surfaces to be cleaned from a trigger
pack after shaking well.
The test plates were then heated in an oven for 30
minute~ to a final temperature of 150C~
The test plates were then either rinsed under a fast
running tap or wiped with a damp sponge and the percentage
removal of baked-on dripping recorded.
Example 1 ~ w/w
Sodium Bicarbonate 6.3
Glycerol 20.0
Sodium Dodecyl Benzene Sulphonate 1.0
25 Veegum T~ 1.5
Xanthan Gum 0.05
Titanium Dioxide 0~5
Water to 100
Product pH 8.4
30 ~ Removal of soil 100
Example 2 ~ w/w
Potassium Bicarbonate 7.5
Glycerol 20.0
35 Sodium Dodecyl Benzene Sulphonate 1.0
6 - ~1211~i'74
Veegum T~D I . 5
Xanthan G~m O . 05
Titanium Diox ide O . 5
Water to lO0
5 Product pH 8.4
~ Removal of soil lO0
Example 3 % w/w
Soda Ash (Sodium rarbonate) 4.0
Glycerol 20O0
lO Sodium Dodecyl Benzene Sulphonate l.0
Veegum T~ 1.5
Xanthan Gum o.i~5
Titanium Dioxide 0.5
Water to lO0
15 Product pH 11.25
~ Removal of soil 100
Example 4 ~ w/w
Sodium Sesquicarbonate 5.65
Glycerol 20.0
20 Sodium Dodecyl Benzene Sulphonate l.0
Veegum T~ 1.5
Xanthan ~um o~o5
Titanium Dioxide 0.5
Water to 100
25 Product pH 10.1
% Removal of soil lO0
Example 5 % w/w
, Sodium Bicarbonate 3.15
j Potassium Bicarbonate 3.75
~'
~ ~.
~X11S~'7~
-- 7 --
Glycerol 20.0
Sodium Dodecyl Benzene Sulphonate 1.0
Veegum T~ 1.5
Xanthan Gum 0.05
5 Titanium Dioxide 0.5
Water to 100
Product pH 8.4
% Removal of soil 100
Note: Use of the bicarbonate mixture gave no improvement
in performance at lower temperatures or shorter
heating time intervals.
Example 6 % w/w
Sodium Bicarbonate 6.3
Sorbitol (70%) 20.0
15 Sodium Dodecyl Benzene Sulphonate 1.0
Veegum T~ 1.5
Xanthan Gum 0.05
Titanium Dioxide 0.5
Water to 100
20 Product pH ~.4
~ Removal of soil 95
Example 7 % w/w
Sodium Bicarbonate 6.3
Ethylene Glycol 20.0
25 Sodium Dodecyl Benzene Sulphonate 1.0
Veegum T~ 1.5
Xanthan Gum 0.05
Titanium Dioxide `0.5
Water to 100
30 Product pH 8.4
~ ~
~IZ~ ;'7~
8 -
Removal of soil 80
Example 8 ~ w/w
Sodium Bicarbonate 6.3
Mannitol 20.0
5 Sodium Dodecyl Benzene Sulphonate 1.0
Veegum T~ 1.5
Xanthan Gum 0 5
Titanium Dioxide o. 5
Water to 100
10 Product pH 8.4
% Removal of soil 92
Example 9 % w/w
Sodium Bicarbonate 6.3
Ethylene Glycol 8.3
15 Sorbitol (70%~ 11.7
Sodium Dodecyl Benzene Sulphonate 1.0
Veegum T~ 1~5
Xanthan Gum o.
Titanium Dioxide 0.5
20 Water to 100
Product pH 8.4
% Removal of soil 93
Note: Mixture of ethylene glycol and sorbitol matches
glycerol with respect to average chain length.
Example 10
A cleaner consisting of the following formulation was
applied to a test surface to be cleaned, prepared as for
Examples 1-9, from an aerosol pack after shaking well. The
test was then carried out in the same manner as for Examples
1-9.
.
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g
~ W/W
Sodium 8icarbonate 5.~7
Glycerol 18.0
Gafteric MD 0 . 036
5 Veegum T~ 1. 35
Xanthan Gum 0.045
Titanium Dioxide 0.45
Deionised Water 64.45
Propellant P12/114:60/40 10.0
10 Product pH 8.4
~ Removal of soil 99
Example 11
A cleaner consisting of the following formulation was
brushed onto a test surface to be cleaned, prepared as for
Examples 1-9. The test was then carried out in the same
m~nner as for Examples 1-9.
% w/w
Sodium Bicarbonate 24.0
Glycerol 76.0
20 % Removal of soil 100
Example 12 % w/w
Potassium Bicarbonate 7.5
Diethylene GLycol 20.0
Sodium Dodecyl Benzene Sulphonate 1.0
25 Veegum T~ 1.5
Xanthan Gum 0.05
Titanium Dioxide 0.5
; Water to 100
Product pH 8.4
30 % Removal of soil 100
`A
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-- 10 -
Example 13 ~ w~w
Potassium Bicarbonate 7.5
Triethylene Glycol 20.0
Sodium Dodecyl Benzene Sulphonate 1.0
5 Veegum T~ 1.5
Xanthan Gum 0.05
Titanium Dioxide 0.5
Water to 100
Product pH 8.4
10 % Removal of soil 100
Example 14 % w/w
-
Potassium Bicarbonate 7.5
Propylene Glycol 20.0
Sodium Dodecyl Benzene Sulphonate 1.0
15 Veegum T~ 1.5
Xanthan Gum 0.05
Titanium Dioxide 0.5
Water to 100
Product pH 8.4
20 ~ Removal of soil 100
Example 15 % w/w
Potassium Bicarbonate 7.5
1,2,6 Hexanetriol 20.0
Sodium Dodecyl Benzene Sulphonate 1.0
25 Veegum T~ 1.5
Xanthan Gum 0.05
Titanium Dioxid~ 0.5
Water to 100
Product pH 8~4
~ ?~, ~
L?~
% Removal of soil 100
Example 16 % w/w
Potassium ~icarbonate 7.5
Dipropylene Glycol 20.0
5 Sodium Dodecyl Benzene Sulphonate 1.0
Veegum T~ 1.5
Xanthan Gum 0.05
Titanium Dioxide 0.5
Water to 100
10 Product pH 8.4
~ Removal of soil 95
Example 17 ~ w/w
Potassium Bicarbonate 7.5
Polypropylene Glycol 15020.0
15 Sodium Dodecyl Benzene Sulphonate 1.0
Veegum T~ 1.5
Xanthan Gum 0.05
Titanium Dioxide 0.5
Water to 100
20 Product pH 8.4
% Removal of soil 95
Example 18 % w/w
Potassium Bicarbonate 7.5
Polyethylene Glycol 200 20.0
25 Sodium Dodecyl Benzene Sulphonate 1.0
Veegum T~ 1.5
Xanthan Gum 0.05
Titanium Dioxide 0.5
Water to 100
1 2 ~2~ 74
Product pH 8.4
96 Removal of soil 95
Example 19 ~ w/w
Potassium Bicarbonate 7.5
Polyethylene Glycol 300 20.0
Sodium Dodecyl Benzene Sulphonate 1.0
Veegum T~ 1.5
Xanthan Gum O.o5
Titanium Dioxide 0.5
10 Water to 100
Product pH 8.4
% Removal of soil 90
Example 20 % w/w
Potassium Bicarbonate 7.5
15 Polyethylene Glycol 600 20.0
Sodium Dodecyl Benzene Sulphonate 1.0
Veegum T~ 1.5
Xanthan Gum 0.05
Titanium Dioxide 0.5
20 Water to 100
Product pH 8.4
Removal of soil 90
The performance of the composition according to
Examples, ~or instance, 1 to 5 was equal to that of a molar
equivalent active level of caustic soda in the same
formulation base.
Caustic soda based products on the market when tested
under identical conditions removed only 80-95% of the
baked-on dripping.
A synergistic effect between the polyhydric alcohol(s)
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lZ1~6'74
- 13 -
and the non-caustic alkali metal salt(s) has been
demonstrated by testing glycerol and sodium bicarbonate
separately alongside a mixture of both on the same prepared
test plate.
.5 Sodium bicarbonate on its own removed onIy 50% of the
baked-on dripping and glyce.rol on its own removed only 30% of
the baked-on dripping where,as the mixture of sodium
bicarbonate and glycerol removed 100% of the baked-on
dripping.
