Note: Descriptions are shown in the official language in which they were submitted.
2022561
Docket: 18237
DR-5189
FIELD OF INVENTION
This invE:ntion concerns acidic cleaning compositions
which are particularly useful in cleaning tile floors. More
specifically, the invention concerns concentrated compositions,
i.e., compositions to which water or other solvent is added prior
to use.
HACRGROUND OF THE INVENTION
Cleaning compositions containing a strong mineral acid
such as hydrochloric acid are known.
U.S. Patent 3,793,221 to Otrhalek describes a
concentrate composition comprising 15-40% of aqueous HC1; 1-6% of
an organic acid selected from oxalic, tartaric and citric acids;
7-23% nonionic surfactant; and 76-24% water. The sum of the
amounts of surfactant is from 10-30% by weight of the
composition, and the nonionic surfactant is about 75-90% by
weight of the total surfactants. For use, the concentrate of
this patent is diluted with from 1 - 5 parts water.
U.S. Patent 4,032, 466 also to Otrhalek discloses acid
cleaning concentrat~ss similar to the compositions of the X221
patent but also coni~aining 1-12% of a flocculating agent. The
water content varie:~ from 75-12%.
U.S. Patent 4,749,508 to Cockrell, Jr, et al discloses
an acidic floor cleanser in ready to use concentrate form
comprising 1-6% of an acid having a pKa value greater than 2.8 at
25°C; typically, citric, tartaric, malic, acetic, glycolic or
gluconic acids. Additionally, the compositions contain 0.1-15%
~ 25 61
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of an acid such as sulfuric, phosphoric, hydrochloric, or nitric
acid with a pKa value of less than 2.5 at 25°C together with
sufficient buffering salt to provide a composition having a pH of
1-6. The composition may also contain a surfactant, fumed silica
or other selected :ingredients.
Schmidt pat al in U.S. Patent 3,443,492 discloses a
process for cleaning evaporation tubes with a mixture of an
organic acid and a mineral acid. The former is utilized in an
amount of from 20-X40% by weight of the total acid in the
composition.
U.S. PatE~nt 3,218,260 to Lewandowski discloses a
cleaning composition comprising an acid in combination with an
anionic surfactant which is an ethoxylated hydrophobic base, the
agent containing at: least 10 moles of ethylene oxide per mole of
the base. The compositions of the patent are said to be
characterized by good clarity in water.
U.S. Pate:nt 4,409,525 to Dodge discloses an etchant
comprising a strong' acid, a weak organic acid, and a water
miscible solvent. A characteristic of the compositions of this
invention is that they contain a minimum amount of water, i.e.
less than 30% by weight.
Martucci, in U.S. Patent 4,675,120 discloses
compositions containing controlled amounts of hydrogen ion, the
availability of which is maintained by combining strong and weak
acid pairs.
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20225fi1
Aqueous glass cleaning compositions are disclosed in
U.S. Patent 4,477,364 to have a pH of less than 1 and contain 1-
13%, HF together with 85-99% mineral hydrocarboxylic or
dicarboxylic acid.
Commercial, floor cleaning products are also known.
One such composition is SURE TRAC'~ sold by the ~rackett Company.
The composition is an aqueous mixture containing an anionic and a
nonionic surfactant together with hydrochloric and glycolic
acids, and is typically used after dilution with water.
Compositions such as SURE TRAC are excellent floor
degreasers and are Especially useful for quarry tile and concrete
floors often providsad in large food dispensing operations such as
fast food restaurants. Although the ready-to-use aspect of such
products is advantageous, they suffer the disadvantage that they
contain large amounts of water. The high proportions of water
adds to the cost of shipping and warehousing. Concentrates, on
the other hand, although less expensive than ready-to-use
compositions are often times not satisfactory because of a
tendency to phase ou.t on storage or when subjected to temperature
stress. Moreover, the manufacture and bulk storage of the
concentrate and before its final packaging for customer use is
difficult in view of the tendency of the concentrate to separate
on standing. In many instances once separation has~occurred, it
is difficult if not impossible to reconstitute and reobtain the
properties of the original composition, especially viscosity.
Accordingly, it is an object of this invention to
provide floor cleaning concentrates which do not suffer the
disadvantages of the high water content compositions and have
good storage stability, even under temperature stress.
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SUMMARY OF THE INVENTION
The cleaning compositions of this invention are
concentrated aqueous compositions which will not separate into
phases on storage even when subjected to temperature abuse. They
comprise aqueous concentrates of water, a mineral acid, an
organic acid and at least one anionic or nonionic surfactant.
They may be employed directly or in admixture with additional
water.
More specifically, the invention provides a phase
stable aqueous cleaning concentrate which does not separate into
two or more phases when stored for 28 days at 125° F, the
concentrate consisting essentially of, by weight based on the
total weight, about 54~ water, about 2~ of an inorganic acid
selected from the group consisting of hydrochloric and
phosphoric acid, about 11~ of an organic acid having a pKa value
of from 1 to 5, and about 32~ of surfactants as a mixture of
nonionic and anionic surfactants at weight ratio of 0.5:1 to
2.1:1.
Unless otherwise noted, all concentrations, including
HC1, are on an anhydrous weight percent active basis.
The presently preferred inorganic acid is hydrochloric
acid because it is easy to use and readily available at a
reasonable cost.
Carboxylic: acids, especially hydroxy carboxylic acids
may be employed. The presently preferred organic acid is
glycolic acid because it is easy to work with and readily
compatible with the other components of the composition.
~~~~~~1
Typically useful carboxylic acids are those acids with pKa
values of above about 1.0 to 5, preferably from 2.5 to 4. These
include, for example:, malic, glycolic, hydroxybenzoic, acetic,
tartaric, gamma hydroxylbutyric, citric and gluconic acids.
Anionic and nonionic surfactants that are compatible
with the highly acidic environment present in the compositions of
the invention are suitable and are present, after dilution of the
concentrate with water in an effective cleaning amount. In the
concentrate composition of the present invention, the surfactant
is present in an amount of from about 12 to about 40% by weight,
preferably from about 24 to about 36%. A blend of an anionic and
a nonionic is particularly suitable, especially in a weight ratio
of nonionic to anionic of from about 0.89:1 to about 1.3:1, most
preferably from about 1.0:1 to about 1.1:1.
Broadly, tlhe anionic surfactants are water-soluble
alkyl or alkylaryl c~~mpounds, the alkyl having from about 8 to
about 22 carbons, in~~luding a sulfate or sulfonate substituent
group that has been base-neutralized, typically to provide an
alkali metal, e.g., aodium or potassium, or an ammonium cation,
including, for example: (1) alkyl and alkylaryl sulfates and
sulfonates having preferably 8 to 18 carbons in the alkyl group,
which may be straight: or branched chain, e.g., sodium lauryl
sulfate and sodium dodecylbenzene sulfonate: (2) alphaolefin aryl
sulfonates preferabl~r having from about 10 to 18 carbons in the
olefin, e.g., sodium X14-16 olefin sulfonate, which is a mixture
of long-chain sulfonate salts prepared by sulfonation of X14-16
alpha-olefins and chiefly comprising sodium alkene sulfonates and
sodium hydroxyalkane sulfonates: (3) sulfated and sulfonated
monoglycerides, especially those derived from coconut oil fatty
acids: (4) sulfate enters of ethoxylated fatty alchols having 1-
t
a ~- ~0~2~~'1
mols ethylene oxide, e.g., sodium polyoxyethylene (7 mol EO)
lauryl ether sulfate, and of ethoxylated alkyl phenols having 10
mole ethylene oxide and 8 to 12 carbons in the alkyl, e.g.,
ammonium poloxyethylene (4 mol EO) nonyl phenol ether sulfate:
(5) base-neutralized esters of fatty acids and isethionic acid,
e.g., sodium lauroy,l isethionate: (6) fatty acid amides of a
methyl tauride, e.g., sodium methyl cocoyl taurate: (7) -
acetoxy- or acetam.ido-alkane sulfonates, and (8) sarcosinates
having from 8 to 22 carbons, e.g., sodium lauroyl sarcosinate.
The nonionics include (1) fatty alcohol alkoxylates,
especially ethoxylal:es, wherein the alkyl group has from 8 to 22,
preferably 12 to 18,, carbons, and typically 6 to 15 mol alkoxide
per molecule, e.g., coconut alcohol condensed with about nine
mols ethylene oxide;' (2) fatty acid alkoxylates having from about
6 to about 15 mols alkoxylate, especially the ethoxylate: (3)
alkylphenoxy alkoxyl.ates, especially the ethoxylates, containing
6 to 12 carbons, preferably octyl or nonyl, in the alkyl, and hav
ing about 5 to 25, ~~referably 5 to 15 mols alkylene oxide per
molecule, e.g., nonl~l phenol ethoxylated with about 9.5 mols
ethylene oxide(Igep~~l~ CO-630); (4) condensates of ethylene oxide
with a hydrophobic vase formed by condensation of propylene oxide
with propylene glycol, e.g., nonionic surfactants of the
Pluronice series manufactured by BASF Wyandotte, (5) condensates
of ethylene oxide with an amine or amide: (6) fatty amine oxides,
e.g., stearyl dimethyl amine oxide, and (7) alkylolamides.
As used in the two preceding paragraphs, water
solubility shall mean that the amount of surfactant or blend of
surfactants used are completely miscible in the compositions of
the present invention, at the water concentration present
therein.
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Preferred avionics are the alkyl and alkylaryl sulfates
and the alpha-olefin aryl sulfonates, which may be included in
the form of the free acid while preferred nonionics are the fatty
alcohol ethoxylates having 6 to 15 cools of ethylene oxide per
molecule.
A number of specific anionic surfactants are available
and can be employed in the practice of this invention. The
presently preferred member of the class is dodecylbenzene
sulfonic acid which is available as CALSOFT'n" LAS-99 from Pilot
Chemical. Other usE:ful anionic surfactants include sodium alpha
olefin sulfonates and sodium lauryl sulfate.
The presently preferred nonionic surfactant is
nonylphenoxypoly (et:hyleneoxy) ethanol having an average of 9
cools of ethylene ox~.de per molecule. It is sold by G.A.F.
Corporation, Chemical Product Division as IGEPAL (CO-630). Other
nonionic surfactant:. useful in the invention include TRITON1'M X-100
which is octylpheno~:ypolyethoxy ethanol containing 9 cools of
ethylene oxide per molecule, sold by Union Carbide, and TERGITOL'~
15-S-7, 15-S-9 or 1~~-S-12. These are polyethylene glycol ethers
of a mixture of synthetic C11-C15 fatty alcohols containing,
respectively 7, 9 and 12 cools of ethylene oxides. These products
are also available from Union Carbide.
The principal and most characteristic property of the
compositions of this invention is that they do not tend to phase
out on storage even when subjected to temperature abuse such as
an alternate freeze-thaw cycle. Preferably, the products of this
invention do not separate into two or more phases when stored for
three months at room temperature and one month at 125°F/51.7oC.
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In addition, the product should preferably pass through at least
one freeze-thaw cyc7.e without separation. When measured by these
criteria, the products of this invention are stable.
Dilute ac~;~eous compositions such as SURE TRAC
containing relatively large amounts of water are phase stable and
do not separate on standing. The stability of the products is
commercially acceptable even at elevated and reduced
temperatures.
It would f~e expected that this phase stability would be
lost as the relative: amount of water in the compositions is
decreased and the relative amounts of the active components
increased. This, indeed, is what is observed with most
compositions of this nature. Surprisingly, however, the
concentrated compositions of this invention have been discovered
to manifest a phase stable concentration zone between phase
unstable zones which are either more or less concentrated in
non-aqueous components. Stability is defined as a composition
that resists separation into two or more phases for a period of
not less than about one month at 100°F.
This unexpected phenomenon is illustrated in the
following Table 1.
_ g _
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TAHLB 1
Component % By Wt. % By Wt. % By Wt.
Blend 1 Blend 2 Blend 3
Dodecylbenzene
sulfonic acid 12 16 20
Nonyl phenol
ethoxylate- 9 cools 12 16 20
ethylene oxide
Glycolic acidl 8.4 11.2 14
Hydrochloric acid2 1.54 2.05 2.56
Water 66.06 54.75 43.44
l: 70% glycolic acid calculated as anhydrous acid
2: 20o Baume (about 32%) hydrochloric acid calculated as
anhydrous acid
When tested for stability by the procedures described
above, it was obser~red that Blends 1 and 3 were unstable, whereas
Blend 2 was stable. It will be noted that in Hlend 1 the amounts
of active components are less than in Blend 2, and that in Blend
3 the % by weight o1' active components is higher than in Blend 2.
Blend 2 remains stable even when subjected to 125°F for 28 days
or to freeze-thaw.
In special situations where high cleaning power is
required, the concentrated compositions of this invention can be
employed directly, i.e. as a ready-to-use composition.
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In most in:atances, however, the selected compositon will
be diluted with wat~ar prior to use or as used. For example, the
composition may be mixed with water at any desired ratio, e.g. at
a concentrate: water ratio of from about 1:250 to about 1:4,
preferably from about 1:125 to 1:24. Alternatively, the
concentrate can be ~uixed with water utilizing any of a variety of
special spray devicEa such as a Gilmore'~ sprayer which may be
attached to a hose t:o siphon the concentrate from a closed
holding vessel. ThE~ dilution rate may be selected based on the
cleaning need.
The actual use of the compositions, with or without
dilution, is conventional, i.e. the composition is applied to the
surface to be cleaned. The surface is scoured to the extent
necessary and then rinsed.
The viscosity of the concentrates of this invention is
from about 50 to 20a cps, preferably from 100 to 150 cps. This
high viscosity is a special advantage when the compositions are
employed in the ready-to-use mode. The reason is that the
viscous compositions do not tend to run so that the active
components remain in contact with the surface to be cleaned.
The mineral and organic acid components of the
composition of the invention assist in the cleansing operation by
functioning as mild etchants. By so doing, they increase the
surface area of the surface to be cleaned, e.g. the tiles,
thereby increasing their non-skid properties. Glycolic acid also
has some chelating ability which contributes to the cleaning
activity.
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The amount of inorganic acid in the compositions is from
about 0.4 to 2.25, preferably 1.5 to 2.0, calculated as active
acid on an anhydrous basis. The amount of organic carboxylic
acid is from about ti to 20, preferably 9 to 13 on the same basis.
The compositions of this invention are preferably
prepared by forming an aqueous solution of the surfactant and
thereafter adding in sequence the selected organic acid followed
by the inorganic acid, e.g., glycolic acid followed by
hydrochloric acid. This order of addition reduces the likelihood
of phasing during manufacture. The acids should be added with
thorough mixing to l:orm homogeneous compositions.
In this di:oclosure and in the claims, the amounts of all
components are calculated as weight percent based on the total
weight of the compo:~ition.
The following examples are given by way of illustration
only and are not to be considered limitations of this invention,
many apparent variations of which are possible without departing
from the spirit or ~~cope thereof.
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EXAMPLES 1 to 24
The :following cleaning concentrates are
illustrative of the compositions of the present invention. In
the examples, the g:Lycolic acid is 70% and the hydrochloric acid
is a 20° Baume. HCl <:omposition.
Example Water I(~EPAL GLYCOLIC CALSOFT HYDROCHLORIC
CO-630 Acid,70% LAS-99 ACID 32%
1 48.1 7_6.0 16.0 14.0 5.9
2 50.6 7.6.0 14.0 14.0 5.4
3 52.1 7.6.0 14.0 12.0 5.9
4 43.6 7.6.0 18.0 16.0 6.4
44.6 7.8.0 16.0 16.0 5.4
6 44.6 7.6.0 18.0 16.0 5.4
7 45.6 7.6.0 18.0 14.0 6.4
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