Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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Backg;round of the Invention
1 Field of the Invention
This invention relates to a thickened acid cleaner
composition and a method of applying the composition to
obtain exterior cleaning of vehicles (such as railroad
rolling stock) without subsequent neutralization of the acid.
2 Description of the Prior Art
Use of acids in cleaning compositions is known. For
instance, U. S. Patent 2,257)467 discloses a solidified acid
composition for cleaning toilet bowls and the like wherein
the composition consists of sodium silicate, water and hydro-
chloric acid. Another acid cleaner is disclosed in U. S.
P~tent 3,271,319 wherein it is taught that stains can be
removed from glass surfaces by the use of an acid cleaner con-
sisting of water, hydrofluoric acid, a carboxymethylcellulose
thickener and a small amount, usually less than 1 percent,
of an alkyl sulfate or alkyl aryl sulfonate wetting agent.
A still more recent patent, U. S. Patent 3J622,~91, teaches
removing aluminide coatings from cobalt base or nickel base
superalloys by the use of a hydrofluoric acid and water compo-
sition which permissibly includes a low foaming or nonfoaming
wetting agent. It is further disclosed that the composition
can be thickened by adding a condensation product of ethylene
oxide with a molecular weight of 4000 and gum tragacanth.
However, the use of this composition requires a follow-up
neutraliza~ion with an alkali solution followed by water
rinsing.
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U S. Patent 3,793,221 teaches the use of a
thickened acid cleaner composition comprising an aqueous
hydrochloric acid, an organic acid, a nonionic surfactant,
an anionic surfactant and water as useful in cleaning vehicles.
Mineral acids have also been used in cleaning com-
positions as a defoamer. This technique is illustrated in
U. S. Patent 3,650,965 wherein the foaming qualities of non-
ionic surfactants for food industry cleaning can be reduced
by the use of an organic acid coupled with a mineral acid
such as phosphoric acid, the acid component being more than
the surfactan~ component.
It has also been known to clean transportation
equipment such as trains, boxcars and the like by the use of
an acid cleaner to remove siliceous soils followed by an
alkaline cleaner to remove organic and oily soils then finally
followed by water rinsing
Summary of the Invention
In accordance with this invention there is provided
a thickened acid cleaner concentrate composition comprising:
(1) an aqueous phosphoric acid in an amount from
about 7 to about 60 weight percent,
(2) a compound selected from the group consisting
of aliphatic alcohols, glycol ethers and mixtures tnereof in
an amount from about 1 to about 6 weight percent,
(3) a nonionic surfactant in an amount from about
7 to about 23 weight percent,
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(~) an anionic surfactant in an amount from about
1 to about 7 weight percent and,
(5) water in an amount from about 8~ to about 4,
weight percent;
all weight percents being based on a total compo-
sition,
provided that said nonionic surfactant and said
anionic surfactant when ta~en together constitute from about
10 to about 30 weight percent of said composition and said
nonionîc surfactant constitutes from about 75 to about 90
weight percent of the combined weight of the nonionic and
anionic sur~actants
The concentrate when diluted with 1 to 2 parts of
water per part of concentrate is used to remove siliceous
and/or oily soils from metal vehicles without a subsequent
alkaline rinsing by flowing on a continuous coat of the
cleaner, allowing the cleaner to remain on the surface of the
vehicle for a period of time followed by a simple rinsing
with water under impingement force pressure.
Description of the Preferred Embodiment
The phosphoric acid employed in this invention may
be either the 75~0 or 100~ phosphoric acid. It is intended
that this is the only acid employed in this composition. In
view of regulatory restric ions regarding environmental
control and waste plant treatment restrictions acids such as
hydroch~oric, sulfuric and organic acids such as oxalic,
tartaric or citric are prohibited. Accordingly, phosphoric
arid is the preferred acid to be employed in this composition
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On a weight percent basis the acid cleaner of this invention
will contain from about 7 to about 80 percent acid and more
preferably the acid content will be from about 20 to~about
~0 weight percent.
The second component of the invented composition
is selected from the group consisting of aliphatic alcohols,
glycol ethers and mixtures thereof wherein the alcohols con-
tain from one to four carbon atoms, the glycol portion of the
glycol ether contains from two to nine carbon atoms and the
alkyl portion of the glycol ether contains from''one to four
carbon atoms. Among the alcohols contemplated are methyl,
ethyl, n-propyl, isopropyl, n-butyl,' isobutyl, sec-butyl and
tertiary butyl. The preferred alcohols are methyl, ethyl, and
isopropyl alcohol
The glycol ethers employed may be monomethyl, ethyl,
n- and isopropyl, n- and isobutyl ethers of ethylene glycol,
diethylene glycol, triethylene glycol, propylene glycol, di-
propylene glycol and tripropylene glycol. The preferred
glycol ethers are the alkyl ethers of ethylene glycol
The particular surfactants employed in the invented
composition in addition to ha~ing a cleaning effect also
exhibit unusual thickening properties for this composition.
Therefore the surfactants of this invention are doubly
critical The nonionic surfactant is present in an amount
from about 7 to about 2~ weight percent of the final composi-
tion and more preferably in an amount from about L2 to 18
weight percent.
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The nonionic surface active agents which are advan-
tageously employed in the compositions of the invention are
generally the polyoxyalkylene adducts of hydrophobic bases
wherein the oxygen/carbon atom ratio in the oxyalkylene
portion of the molecule is greater than 0 40. Those compo-
sitions which are condensed with hydrophobic bases ~o provide
a polyoxyalkylene portion having an oxygen/carbon atom ratio
greater than 0 40 include ethylene oxide, butadiene dioxide
and glycidol, mixtures of these alkylene oxides with each
other and with minor amounts of propylene oxide, butylene
oxide, amylene oxide, styrene oxide,and other higher molec-
ular weight alkylene oxides. Ethylene oxide, for example,
is condensed with the hydrophobic base in an amount suffi-
cient to impart water dispersibility or solubility and
surface active properties to the molecule being prepared
The exact amount of ethylene oxide condensed with the hydro-
phobic base will depend upon the chemical characteristics of
the base employed and is readily apparent to those ofordinary
skill in the art relating to the synthesis of oxyalkylene
surfactant condensates.
Typical hydrophobic bases which can be condensed
with ethylene oxide in order to prepare nonionic surface
active agents include mono- and polyalkyl phenols, polyoxy-
propylene condensed with a base having from about 1 to 6
carbon atoms and at least one reactive hydrogen atom, fatty
acids, fatty amides and fatty alcohols. The hydrocarbon
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ethers such as the benzyl or lower alkyl ether of the poly-
oxyethylene surfactant condensates are also advanta~eously
employed in the compositions of the invention.
Among the suitable nonionic surface active agents
are the polyoxyethylene condensates of alkyl phenols having
from about 6 to 20 carbon atoms in the alkyl portion and from
about 5 to 30 ethenoxy groups in the polyoxyethylene radical
The alkyl substituent on the aromatic nucleus may be octyl,
diamyl, n-dodecyl, polymerized propylene such as propylene
tetramer and trimer, isoctyl, nonyl, etc. The benzyl ethers
of the polyoxyethylene condensates of monoalkyl phenols
impart good properties to the compositions of the invention
and a typical product corresponds to the formula:
C8Hl-~ ~ (OCH2CH2) l50CH2C~sH5
Higher polyalkyl oxyethylated phenols corresponding to the
formula:
R
Rl ~ o( CH2CH2Cl) nH
wherein R is hydrogen or an alkyl radical having from about
1 to 12 carbon atoms, Rl and R2 are alkyl radicals having
from about 6 to 16 carbon atoms and n has a value from about
5 to 30 are also suitable as nonionic sur~ace active agents.
A typical oxyethy~ated polyalkyl phenol is dinonyl phenol
condensed with 1~ moles of ethylene oxide.
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10958~;
Other suitable nonionic surface active agents are
cogeneric mixtures of conjugated polyoxyalkylene compounds
containing in their structure at least one hydrophobic oxy-
alkylene chain in which the oxygen/carbon atom ratio does
not exceed 0.40 and at least one hydrophilic oxyalkylene
chain in which the oxygen/carbon atom ratio is greater than
0 40.
Polymers of oxyalkylene groups obtained from
propylene oxide, butylene oxide J amylene oxide, styrene
oxide, mixtures of suchoxyalkylene groups with each other
and with minor amounts of polyoxyalkylene groups obtained
from ethylene oxide, butadiene dioxide, and glycidol are
illustrative of hydrophobic oxyalkylene chains having an
oxygen/carbon atom ratio not exceeding 0 40. Polymers of
oxyalkylene groups obtained from ethylene oxide, butadiene
dioxide, glycidol, mixtures of such oxyalkylene groups with
each other and with minor amounts of oxyalkylene groups
obtained from propylene oxide, butylene oxide, amylene
oxide and styrene oxide are illustrative of hydrophilic
oxyalkylene chains having an oxygen/carbon atom ratio
greater than 0.40.
Further suitable nonionic surface active agents
are the polyoxyethylene esters of higher fatty acids having
from about 8 to 22 carbon atoms in the acyl group and from
about 5 to 30 ethenoxy units in the oxyethylene portion.
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.
Typical products are the polyoxyethylene adducts of tall
oil, rosin acids, lauric, stearic and oleic acids and the
like Additional non-îonic surface active agents are the
polyoxyethylene condensates of higher fatty acid amines and
amides having from about 8 to 22 carbon atoms in the fatty
alkyl or acyl group and about 10 to 30 ethenoxy units in
the oxyethylene portion. Illustrative products are coconut
oil fatty acid amides condensed with about 5 to 30 moles of
ethylene oxide
Other suitable polyoxyalkylene nonionic surface
active agents are the alkylene oxide adducts of higher
aliphatic alcohols and thioalcohols having from about 8 to
22 carbon atoms inthealipha~ic portionandabout5 to30 inthe
oxyalkylene portion Typical products are synthet~c fatty
alcohols, such as n-decyl, n-undecyl, n-dodecyl, n-tridecyl,
n-tetradecyl, n-hexadecyl, n-octadecyl and mixtures thereof
condensed with 5 to 30 moles of ethylene oxide, a mixture of
normal fatty alcohols condensed with 8 to 20 moles of
ethylene oxide and capped with benzyl halide or an alkyl
halide, a mixture of normal fatty alcohols cond~nsed with
5 to 30 moles of a mixture of ethylene and propylene oxides,
a mixture of se~eral fatty alcohols condensed sequentially
with 2 to 20 moles of ethylene oxide and 3 to 10 moles of
propylene oxide, in either order; or a mixture of normal
fatty alcohols condensed with a mixture of propylene and
ethylene oxides~ in which the oxygen/carbon atom ratio is
losssbs
less than 0.~0 follo~ed by a mixture of propylene and
ethylene oxides in which the oxygen/carbon atom ratio is
greater than 0 40 or a linear secondary alcohol condensed
with ~ to 30 moles of ethylene oxidej or a linear secondary
alcohol condensed with a mixture of propylene and ethylene
oxides, or a linear secondary alcohol condensed with a mixture
of ethylene, propylene, and higher alkylene oxides.
Of the foregoing described nonionic surface active
agents or surfactants, a particularly preferred group is the
polyethylene oxide condensates of alkyl phenols, particularly
those having an alkyl group containing from about 6 to 12
carbon atoms in either a straight chain or branch chain
configuration with ethylene oxide, the ethylene oxide being
present in arnounts equal to ~ to 2~ moles of ethylene oxide
per mole of alkyl phenol. This group of surfact~ants is
exemplified by octylpheno~ypolyethoxyethanol
The second component of the surfactant system of
this invented composition is an anionic surfactant which is
present in an amount from about 1 to about 7 weight percen~
and more preferably in an amount from about 2 to about
percent.
Anionic synthetic non-soap detergents can bebroadly
described as organic sulfuric and sulfonic acid reaction
products having in their molecular structure an al~yl radical
containing from about 8 to about 22 carbon atoms and a radical
selected from the group consisting of sulfonic acid and
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sulfuric acid ester radicals. (Included in the term alkyl
is the alkyl portion of higher acyl radicals.) Important
examples of the synthetic detergents which form a part of
the preferred cornpositions of the present invention are
those obtained by sulfating the higher alcohols (C8-Cl3
carbon atoms) produced by reducing the glycerides of tallow
or coconut oil; alkyl benzene sulfonates, in which the alkyl
group contains from about 9 to about 15 carbon atoms, includ-
ing those of the types described in United States Letters
Patent Nos. 2,220,099 and 2,477,~8~ (the alkyl radical can
be a straight or branched aliphatic chain), alkyl glyceryl
ether sulfonates, especially those ethers of the higher
alcohols derived from tallow and coconut oil; coconut oil
fatty acid monoglyceride sulfates and sulfonates; sulfuric
acid esters of the reaction product of one mole of a higher
fatty alcohol (e.g , tallow or coconut oil alcohols) and
about 1 to 6 moles of ethylene oxide; sulfuric acid and
sulfonic acid esters of the reaction product of one mole of
a higher fatty oil (e.g , coconut or castor oil) and about
1 to 6 moles of ethylene oxide; alkyl phenolethylene oxide
ether sulfate with about 1 to about 10 units of ethylene
oxide per molecule and in which the alkyl radicals contain
from 8 to about 12 carbon atoms; the reaction product of
fatty acids esterified with isethionic acid where, for
example, the fatty acids are derived from coconut oil; fatty
acid amide of a methyl tauride in which the fatty acids, for
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exam?le, are derived from coconut oil; and others known in
the art, a num~er being specifically set forth in United
States Letters Patent Nos, 2,486,921, 2,486,922 and
2,~96,278, While less preferred the sodium and potassium
salts of the foregoing sulfonic and sulfuric acid and/or
ester anionic surfactants can also be used, The foregoing
anionic surfactants are further exemplified in McCutcheon's
Deter~ents & Emulsifiers, 1972 Annual, Allured Publishing
Corporation, Ridgewood, New Jersey,
Particularly suited for the process and composition
of this invention are the alkyl or aryl sulfonic acid anionic
surfactants exemplified by a linear alkyl benzene sulfonic
acid,
When taken together in considering the foregoing
nonionic and anionic surfactants, it is critical to ~he
success of this invention that the total amount of surfactant
present constitute from about 10 to about 30 weight percent
of the total cleaner composition and that the noni.onic
portion of the total surfactant portion be from about 75 to
about 95 weight percent,
The final component of the invented clean;ng com- .
position is water which is present in an amount from about
83 to about 4 percent by weight and preferably in an amount
from about 80 to about 10 weight percent,
In addition to the foregoing ingredients, as is
well known in the detergent arts, to the cleaning cOmpGSitiOn
can be added such things as dyes, perfumes, corrosion inhib-
itors and the like which do not detract from the present,
invention,
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The foregoing acid thickened cleaner concentrate
composition is diluted with water at the point of use to
obtain the final cleaning composition. This dilution is
preferably about 2 parts of water for each part of cleaner;
however, dilution ratios of from about 1 part to about 8
parts of water per part of cleaner concentrate are satis-
factory
The compositions of this invention are prepared by
standard well-known open kettle mixing techniques known in
the industry, A convenient charge schedule for preparation
of the composition at room temperature would be to charge
the water to the vessel, add the alcohol, followed by the
nonionic surfactant, then the anionic surfactant and finally
the phosphoric acid Should it be desired to add other
optional modifiers to the composition such as dyes, perfumes
and inhibitors they can be added as !convenient durirlg the
preparation of the composition.
The thickened acid cleaner concentrate after
dilution is flowed onto the vehicle to be cleaned in an
amount to obtain physical coverage of the vehicle so that
a thin but continuous film is obtained No brushing, scrub-
bing or other similar effort is required The cleaner is
allowed to remain at least one minute and preferably five
minutes, however, up to ~0 minutes is satisfactory when the
vehicle is cleaned during cold weather. It is an advantage
l~)9S805
of the present composition that even if the water component
of the composition evaporates during the period or applica-
tion the cleaner can still be successfully rinsed afterwards.
Rinsing is achieved by the use of water being sprayed on the
vehicle with impingement force and is most conveniently
achieved by simply passing the vehicle through the spray
rinse. For locomotives a water delivery rate of 150 to 200
gallons per minute and at a pressure of 100 to 200 pounds per
square inch is satisfactory. Preferably the rinse will be
applied at an angle starting at one end of the locomotive
and sweeping forward to the other end and then re~ersing the
angle and sweeping backward to the point of beginning. While
the type of vehicle being washed will dictate the type of
equipment being used, the acid cleaner composition of this
invention is suitable for trucks and trailers, busses, air-
planes, railroad engines, boxcars, passenger cars, cabooses,
off-road equipment and similar equipment
The acid cleaner composition of this invPntion
avoids many of the problems associated with prior art clean-
ing compositions For instance, the previously used inert
thickeners presented problems in removing the thicl~ener res;-
due after the washing, contributed to dry down problems and
the simple disposal problem of the thic~ener residue after
it was removed from the c~eaned vehicle. Dry do~ of course
refers to the drying of the cleaner film prior to lts re-
moval. It is recognized o~ course that the acid cleaner can
109S80:;
be used with wa~er of any hardness in contrast to alkaline
cleaners which are dependent upon a certain degree of water
softness in order to obtain desirable effects, In contrast,
the present composition with its novel arrangement of sur-
factants has increased cleaning efficiency, requires no ,
alkaline treatment afterwards, avoids the physical handling
problem of the inert thickener residues and additionally
facilitates the removal of the organic and oily road soils
from the water while the water is in the holding tanks and
ponds prior to being discharged into the natural waterways.
The practice of this invention is illustrated by,
but not limited by the examples given below, Unless other-
wise noted all parts or percents are parts or percents
respectively by weight,
Example 1
To an open kettle mixing vessel was charged 51
parts of water followed by 2 parts of isopropyl alcohol, Then
12 parts of octylphenoxy polyethoxyethanol (TRITON X-10~ ~ a
nonionic surfactant of the ethoxylated monohydric alcohol
type was added, With continuing mixing 4,5 parts of linear
alkyl benzene sulfonic acid anionic surfactant of the alkane
sulfonate type (CALSOFT LAS-99~ was blended in, Finally ~0
parts of 75~ phosphoric acid was added. The completed thick-
ened acid cleaner WaS then discharged from the mixing vessel,
The foregoing concen,rate was diluted with 2volumes
of water and stirred to obtain a uniform mixture, The acid
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cleaner composition was then applied to a dirty locomotive.
Approximately 3 gallons were applied to the locomotive. The
cleaner was allowed to remain on the locomotive for approxi-
mately 5 minutes, The locomotive was then rinsed by driving
the locomotive forward through a fixed spray at a speed of
5 to 8 miles an hour and then reversing the locomotive and
bringing it back through the fixed spr~ys once more so that
the water was applied at two different angles, The water
pressure and delivery rate was 200 gallons of water per
minute at 200 pounds per square inch. When dry the loco-
motive was uniformly clean, free of residual siliceous road
soils and oily road soils, had no streaks or spots left from
the washing and the painted surface was unaffected by the
wash treatment,
Example 2
~n this example the cleaning effectiveness of the
acid concentrate as prepared in Example 1 at various dilu-
tions was compared. Laboratory cleaning of metal coupons was
employed, The coupons soiled with oil were cleaned by flow-
ing on the cleaner at the dilutions noted below. UpGn
standing for 10 minutes the coupons were inspected for dry
down, i,e., dryness due to evaporation of water, They were
then rinsed and evaluated for cleaning. The cleaning or
soil removal was rated on a scale of 0 to 10 with 10 being
completely clean, A rating of less than 7 is considered
unsatisfactory. The results are tabulated below:
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Concentrated Cleaner
Dry Down No
Cleaning rat~ 9
Diluted 1:2 with water
Dry Down No
Cleaning rate 8
Diluted 1:4 with water
Dry Down No
- Cleaning rate 6
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