U.S. patent application number 14/651050 was filed with the patent office on 2015-11-05 for cleaning composition for metal articles.
The applicant listed for this patent is PARKER-HANNIFIN CORPORATION. Invention is credited to Charles L. HAWES.
Application Number | 20150315712 14/651050 |
Document ID | / |
Family ID | 48045077 |
Filed Date | 2015-11-05 |
United States Patent
Application |
20150315712 |
Kind Code |
A1 |
HAWES; Charles L. |
November 5, 2015 |
CLEANING COMPOSITION FOR METAL ARTICLES
Abstract
An aqueous cleaning composition includes at least one acid
fluoride salt selected from ammonium bifluoride, sodium bifluoride,
potassium bifluoride, calcium fluorophosphates, sodium
fluorosilicates, and combinations of two or more thereof; at least
one mineral acid adduct of urea; at least one surfactant; and at
least one organic solvent. The cleaning composition is effective in
removing deposited soil and corrosion products on a metal surface,
particularly aluminum and aluminum alloy surfaces.
Inventors: |
HAWES; Charles L.; (Cordova,
TN) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
PARKER-HANNIFIN CORPORATION |
Cleveland |
OH |
US |
|
|
Family ID: |
48045077 |
Appl. No.: |
14/651050 |
Filed: |
March 15, 2013 |
PCT Filed: |
March 15, 2013 |
PCT NO: |
PCT/US13/31819 |
371 Date: |
June 10, 2015 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61736777 |
Dec 13, 2012 |
|
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|
Current U.S.
Class: |
510/257 |
Current CPC
Class: |
C23G 1/125 20130101;
C11D 3/43 20130101; C23F 3/03 20130101; C11D 3/323 20130101; C11D
3/046 20130101; C11D 11/0029 20130101 |
International
Class: |
C23G 1/12 20060101
C23G001/12 |
Claims
1. An aqueous cleaning composition comprising: at least one acid
fluoride salt selected from ammonium bifluoride, sodium bifluoride,
potassium bifluoride, calcium fluorophosphates, sodium
fluorosilicates, and combinations of two or more thereof; at least
one mineral acid adduct with urea; at least one surfactant; and at
least one organic solvent.
2. The aqueous cleaning composition of claim 1 wherein the acid
fluoride salt is ammonium bifluoride.
3. The aqueous cleaning composition of claim 1 wherein the mineral
acid adduct with urea is selected from among the adducts of urea
with perchloric acid; hydroiodic acid; hydrobromic acid;
hydrochloric acid; sulfuric acid; nitric acid; phosphoric acid and
combinations of two or more thereof.
4. The aqueous cleaning composition of claim 1 wherein the
surfactant comprises a nonionic surfactant.
5. The aqueous cleaning composition of claim 4 wherein the nonionic
surfactant comprises an ethoxylated alcohol.
6. The aqueous cleaning composition claim 1 wherein the surfactant
comprises a cationic surfactant.
7. The aqueous cleaning composition of claim 6 wherein the cationic
surfactant comprises dicocodimethyl ammonium chloride.
8. The aqueous cleaning composition of claim 1 wherein the
surfactant comprises an amphoteric surfactant.
9. The aqueous cleaning composition of claim 8 wherein the
amphoteric surfactant comprises cocoamidopropyl betaine.
10. The aqueous cleaning composition of claim 1 wherein the organic
solvent comprises diethylene glycol monobutyl ether.
11. The aqueous cleaning composition of claim 1 wherein the
composition is diluted with water in a ratio of cleaning
composition:water of 1:1 to 1:10.
12. An aqueous cleaning composition comprising: from about 1% to
about 10% by weight of at least one acid fluoride salt selected
from ammonium bifluoride, sodium bifluoride, potassium bifluoride,
calcium fluorophosphates, sodium fluorosilicates, and combinations
of two or more thereof; from about 2% to about 20% by weight of at
least one mineral acid adduct with urea; from about 1% to about 10%
by weight at least one surfactant; and from about 1% to about 10%
by weight at least one organic solvent.
13. The aqueous cleaning composition of claim 12 comprising: from
about 1% to about 10% by weight of ammonium bifluoride; from about
2% to about 20% by weight of at least one mineral acid adduct with
urea selected from the adducts of urea with perchloric acid;
hydroiodic acid; hydrobromic acid; hydrochloric acid; sulfuric
acid; nitric acid; phosphoric acid and combinations of two or more
thereof; from about 1% to about 10% by weight at least one
surfactant; and from about 1% to about 10% by weight at least one
organic solvent.
14. A method of cleaning a metal surface, the method comprising:
contacting the metal surface with an aqueous cleaning composition
for a sufficient time to clean the metal surface, the aqueous
cleaning composition comprising: at least one acid fluoride salt
selected from ammonium bifluoride, sodium bifluoride, potassium
bifluoride, calcium fluorophosphates, sodium fluorosilicates, and
combinations of two or more thereof; at least one mineral acid
adduct with urea; at least one surfactant; and at least one organic
solvent.
15. The method of claim 14 wherein the acid fluoride salt is
ammonium bifluoride.
16. The method of claim 14 wherein the mineral acid adduct with
urea is selected from among the adducts of urea with perchloric
acid; hydroiodic acid; hydrobromic acid; hydrochloric acid;
sulfuric acid; nitric acid; phosphoric acid and combinations of two
or more thereof.
17. A method of cleaning a metal surface, the method comprising:
contacting the metal surface with an aqueous cleaning composition
for a sufficient time to clean the metal surface, the aqueous
cleaning composition comprising: from about 1% to about 10% by
weight of at least one acid fluoride salt selected from ammonium
bifluoride, sodium bifluoride, potassium bifluoride, calcium
fluorophosphates, sodium fluorosilicates, and combinations of two
or more thereof; from about 2% to about 20% by weight of at least
one mineral acid adduct with urea; from about 1% to about 10% by
weight at least one surfactant; and from about 1% to about 10% by
weight at least one organic solvent.
18. The method of claim 17 wherein the mineral acid adduct with
urea is selected from among the adducts of urea with perchloric
acid; hydroiodic acid; hydrobromic acid; hydrochloric acid;
sulfuric acid; nitric acid; phosphoric acid and combinations of two
or more thereof.
Description
TECHNICAL FIELD
[0001] The invention related generally to a composition for
cleaning metal surfaces, and in particular, to an aqueous
composition for cleaning aluminum and aluminum alloys.
BACKGROUND
[0002] Although aluminum is generally considered to be a bright
metal, aluminum and aluminum alloy surfaces often present a dull
appearance due to build up of grease and dirt, particularly on
industrial machinery and equipment. Chemical and electrochemical
solutions have been developed to create a highly-reflective surface
on aluminum and aluminum alloy bodies.
[0003] Many of the available cleaning compositions require elevated
temperatures, e.g., temperatures at or above 120.degree. C., to be
effective. Other cleaning compositions are alkaline, which may
cause corrosion and pitting of the metal surface. Acidic cleaning
compositions have been used, but many contain components that
present a safety risk to the user and/or are harmful to the
environment.
SUMMARY
[0004] In one aspect of the invention, there is provided an aqueous
cleaning composition including: at least one acid fluoride salt
selected from ammonium bifluoride, sodium bifluoride, potassium
bifluoride, calcium fluorophosphates, sodium fluorosilicates, and
combinations of two or more thereof; at least one mineral acid
adduct with urea; at least one surfactant; and at least one organic
solvent.
[0005] In one embodiment, the mineral acid adduct with urea is
selected from among the adducts of urea with perchloric acid (urea
perchloride); hydroiodic acid (urea hydroiodide); hydrobromic acid
(urea hydrobromide); hydrochloric acid (urea hydrochloride and urea
dihydrochloride); sulfuric acid (urea sulfate); nitric acid (urea
nitrate and urea dinitric acid); phosphoric acid (urea phosphate)
and combinations of two or more thereof.
[0006] In one embodiment, the acid fluoride salt is ammonium
bifluoride.
[0007] In one embodiment, the surfactant includes a nonionic
surfactant. The nonionic surfactant may include an ethoxylated
alcohol.
[0008] In one embodiment, the surfactant includes an amphoteric
surfactant. The amphoteric surfactant may include cocoamidopropyl
betaine.
[0009] In one embodiment, the organic solvent includes diethylene
glycol monobutyl ether.
[0010] In one aspect of the invention, there is provided an aqueous
cleaning composition including: from about 1% to about 10% by
weight of at least one acid fluoride salt selected from ammonium
bifluoride, sodium bifluoride, potassium bifluoride, calcium
fluorophosphates, sodium fluorosilicates, and combinations of two
or more thereof; from about 2% to about 20% by weight of at least
one mineral acid adduct with urea; from about 1% to about 10% by
weight at least one surfactant; and from about 1% to about 10% by
weight at least one organic solvent.
[0011] The aqueous cleaning composition may be diluted with water
in a ratio of cleaning composition:water of 1:1 to 1:10. In one
embodiment, the aqueous cleaning composition is diluted with water
in a ratio of 1 part cleaning composition to 3 parts water.
[0012] In one aspect of the invention, there is provided a method
of cleaning a metal surface, the method including: contacting the
metal surface with an aqueous cleaning composition for a sufficient
time to clean the metal surface, the aqueous cleaning composition
including: at least one acid fluoride salt selected from ammonium
bifluoride, sodium bifluoride, potassium bifluoride, calcium
fluorophosphates, sodium fluorosilicates, and combinations of two
or more thereof; at least one mineral acid adduct with urea; at
least one surfactant; and at least one organic solvent.
BRIEF DESCRIPTION OF DRAWINGS
[0013] FIG. 1 is a plot of the percent clean of a soiled aluminum
substrate vs. percent ammonium bifluoride content in a cleaning
solution in accordance with the present invention.
[0014] FIG. 2 is a plot of the percent clean of an oxidized
aluminum substrate vs. percent ammonium bifluoride content in a
cleaning solution in accordance with the present invention.
[0015] FIG. 3 is a bar graph of the percent clean of a soiled
aluminum substrate for cleaning solutions containing various
mineral acid adducts with urea in accordance with the present
invention.
[0016] FIG. 4 is a bar graph of the percent clean of an oxidized
aluminum substrate for cleaning solutions containing various
mineral acid adducts with urea in accordance with the present
invention.
[0017] FIG. 5 is a bar graph of the percent clean of an oxidized
aluminum substrate for comparative cleaning solutions containing
different concentrations of ammonium bifluoride.
DETAILED DESCRIPTION
[0018] The composition of the present invention is an aqueous
acidic composition that is useful in cleaning metal surfaces, and
in particular, aluminum and aluminum alloy surfaces. More
specifically, the composition described herein is particularly
useful for cleaning evaporator coils, heating coils and air-cooled
condensers to remove deposits that build up on the coils, which can
interfere with proper operation of the coils. The cleaning
composition is effective in producing a brightened surface for
aluminum and aluminum alloys.
[0019] The invention described herein includes a concentrated
cleaner that safely removes dirt and oxidation in a uniform manner
resulting in a brightening effect on aluminum fin stock used in the
HVAC industry. More specifically, the composition of the present
invention provides for an effective cleaning composition that
removes accumulated dirt and oxidation in a manner that is safer
for the manufacturer, end user and the environment than
conventional hydrofluoric acid and mineral acid compositions.
[0020] Hydrofluoric acid has been a staple ingredient in HVAC coil
cleaning for many years. This is mainly because it effectively
dissolves aluminum metal very rapidly at a rate unlike any other
commonly used acid. It also has a brightening effect on the cleaned
metal that is typically better than most conventional compositions.
Any residual unreacted hydrofluoric acid quickly reacts with
calcium in the environment and forms an inert compound that has
very low solubility in water, thereby does not enter the water
supply in a significant way. These HF compositions usually contain
a mineral co-acid such as sulfuric or phosphoric acids or other
acid of a lower pKa to push the equilibrium for HF to the left
as:
HF .revreaction. Aq H + + F - ##EQU00001## HF + H 2 SO 4
.revreaction. Aq H + + F - + 2 H + + SO 4 - 2 ##EQU00001.2## 3 HF +
Al 0 .fwdarw. Aq Al + 3 ( 6 H 2 O ) 3 F - + 3 / 2 H 2 .uparw.
##EQU00001.3##
[0021] The above equations show that it is the HF species that
attacks the aluminum metal underneath the oxide layer. Any soluble
oxide is removed in the process along with oxide attached to the
aluminum metal surface. When this reaction is quenched with rinse
water, an aluminum fluoride film is left on the remaining fin stock
giving an appearance of a brighter surface than an aluminum oxide
surface. However, the downside to using hydrofluoric acid is that
it is extremely hazardous. Hydrofluoric acid is dangerous to use
because of the reactivity with calcium ion in the body that can
cause heart failure. It is very penetrating through the skin and is
very volatile so as to be an inhalation route hazard as well as a
skin corrodent. In addition, hydrofluoric acid is a dangerous
product to manufacture, to store, to blend into a formula, to
dilute and during application.
[0022] Some of the hazards of using hydrofluoric acid may be
circumvented by the use of ammonium bifluoride and a co-acid.
Co-acids are typically chosen from two groups: mineral acids such
as sulfuric and phosphoric acids; and organic co-acids such as
citric and hydroxyacetic acids. However, the cleaning performance
and the brightening effect have been unsatisfactory with the
available non-HF/organic acid formulations.
[0023] The benchmark for performance in aluminum cleaning and
brightening as mentioned above, are the hydrofluoric acid
containing formulations with the aforementioned hazards. An example
of a commercially available cleaning composition is Acti-Brite from
Virginia Corporation, which contains about 15-18% hydrofluoric
acid, 5-7% phosphoric acid and surfactants. An example of a
commercially available ammonium bifluoride with organic co-acid
product is Calbrite from NuCalgon Corporation. Analysis of Calbrite
shows it to contain about 10-13% ammonium bifluoride, about 3-5%
hydroxyacetic acid, and surfactants.
[0024] As used herein, the term "brightening" means improving the
clarity or distinctness of an image reflected by a metal
surface.
[0025] As used herein, the term "substantially free of" means the
composition is completely lacking the component or having such a
small amount of the component that the component does not affect
the performance of the composition. The component may be present as
an impurity or as a contaminant, and is present in an amount that
is less than 0.5% by weight. In another embodiment, the component
is present in an amount that is less than 0.1% by weight, and in
yet another embodiment, the component is present in an amount that
is less than 0.01% by weight.
[0026] The cleaning composition of the present invention includes
an acid fluoride salt, a mineral acid adduct of urea, at least one
surfactant, a water miscible organic solvent and water.
[0027] Suitable acid fluoride salts include metal fluorides,
including alkali metal fluorides, and ammonium fluorides. Examples
of such acid fluoride salts include ammonium bifluoride, sodium
bifluoride, potassium bifluoride, calcium fluorophosphates and
sodium fluorosilicates, and combinations of two or more thereof.
Preferably, the acid fluoride salt includes ammonium
bifluoride.
[0028] As part of an effective cleaning composition, the acid
fluoride salt concentration level may suitably be from about 1 to
about 30% by weight, based on the total weight of the composition.
In one embodiment, the acid fluoride salt concentration level is
within the range of about 1 to about 25% by weight, or within the
range of about 1 to about 10% by weight, or within the range of
about 4 to about 6% by weight.
[0029] The composition includes at least one adduct of a mineral
acid with urea. Particularly useful mineral acids are strong
mineral acids. Table 1 below lists mineral acids with their
respective relative strengths expressed by the pKa scale.
TABLE-US-00001 TABLE 1 Acid pKa Fluoroantimonic acid HSbF.sub.6
<-12 Hydroiodic HI -10 Perchloric HClO.sub.4 -10 Sulfuric
H.sub.2SO.sub.4 pKa.sub.1 -10 HSO.sub.4.sup.- pKa.sub.2 2.0
Hydrobromic HBr -9 Hydrochloric HCl -7 Nitric HNO.sub.3 -1.3
Phosphoric H.sub.3PO.sub.4 pKa.sub.1 2.1 H.sub.2PO.sub.4.sup.-
pKa.sub.2 7.2 HPO.sub.4.sup.-2 pKa.sub.3 12.3 Hydrofluoric HF 3.2
Water H.sub.2O 15.7
[0030] Suitable adducts of mineral acids with urea include adducts
of urea with perchloric acid (urea perchloride); hydroiodic acid
(urea hydroiodide); hydrobromic acid (urea hydrobromide);
hydrochloric acid (urea hydrochloride and urea dihydrochloride);
sulfuric acid (urea sulfate); nitric acid (urea nitrate and urea
dinitric acid); phosphoric acid (urea phosphate) and combinations
of two or more thereof.
[0031] Adducts of mineral acids with urea may be prepared directly
from the components or their solutions or by the action of mineral
acids on cyanamide, in which case the latter decompose to give
urea, which then enters into the adduct with the acid.
[0032] Urea hydrochloride is an organic acid salt that can be
prepared by reacting urea with hydrogen chloride. In one
embodiment, urea hydrochloride is added in salt form to the
cleaning composition. The urea hydrochloride may be a
monohydrochloride or a dihydrochloride. In another embodiment, the
urea hydrochloride is formed in situ by adding urea and
hydrochloric acid to the cleaning composition.
[0033] According to certain preferred embodiments, the composition
is substantially free of added hydrofluoric acid.
[0034] As part of an effective cleaning composition, the
urea:mineral acid adduct concentration level may suitably be from
about 1 to about 30% by weight, based on the total weight of the
composition. In one embodiment, the urea hydrochloride
concentration level is within the range of about 2 to about 25% by
weight, or within the range of about 2 to about 20% by weight, or
within the range of about 2 to about 15% by weight, or within the
range of about 2 to about 10% by weight.
[0035] The pH of the composition is in the range of about 0.05 to
7. In one embodiment, the pH of the composition is between about
0.5 and about 6.5. In one embodiment, the pH of the composition is
between about 1.0 and about 5.0. In one embodiment, the pH of the
composition is between about 0.5 and 4.5.
[0036] The cleaning composition contains at least one surfactant.
The surfactant or surfactant mixture may be selected from water
soluble or water dispersible nonionic, anionic, cationic,
zwitterionic or true amphoteric surfactants.
[0037] Exemplary nonionic surfactants include polyoxyalkylene alkyl
(or alkenyl) esters obtained by adding 3 moles to 30 moles of an
alkylene oxide having 2 to 4 carbon atoms to an aliphatic alcohol
having 10 to 18 carbon atoms, wherein examples of the aliphatic
alcohol used include primary alcohols and secondary alcohols in
which the alkyl group thereof may also be branched, and the
aliphatic alcohol is preferably a primary alcohol; polyoxyethylene
alkyl (or alkenyl)phenyl ethers; fatty acid alkyl ester alkoxylates
obtained by adding an alkylene oxide between the ester bonds of a
long chain fatty acid alkyl ester; polyoxyethylene sorbitan fatty
acid esters; polyoxyethylene sorbitol fatty acid esters;
polyoxyethylene fatty acid esters; polyoxyethylene hydrogenated
castor oil; glycerin fatty acid esters; fatty acid alkanolamides;
polyoxyethylene alkylamines; alkyl glycosides; and alkylamine
oxides. In certain embodiments, the nonionic surfactant includes an
ethoxylated alcohol.
[0038] Exemplary anionic surfactants include alcohol sulfates and
sulfonates, alcohol phosphates and phosphonates, alkyl ester
sulfates, alkyl diphenyl ether sulfonates, alkyl sulfates, alkyl
ether sulfates, sulfate esters of an alkylphenoxy polyoxyethylene
ethanol, alkyl monoglyceride sulfates, alkyl sulfonates, alkyl
ether sulfates, alpha-olefin sulfonates, beta-alkoxy alkane
sulfonates, alkyl ether sulfonates, ethoxylated alkyl sulfonates,
alkylaryl sulfonates, alkylaryl sulfates, alkyl monoglyceride
sulfonates, alkyl carboxylates, alkyl ether carboxylates, alkyl
alkoxy carboxylates having 1 to 5 moles of ethylene oxide,
alkylpolyglycolether sulfates (containing up to 10 moles of
ethylene oxide), sulfosuccinates, octoxynol or nonoxynol
phosphates, taurates, fatty taurides, fatty acid amide
polyoxyethylene sulfates, acyl glycerol sulfonates, fatty oleyl
glycerol sulfates, alkyl phenol ethylene oxide ether sulfates,
paraffin sulfonates, alkyl phosphates, isethionates, N-acyl
taurates, alkyl succinamates and sulfosuccinates,
alkylpolysaccharide sulfates, alkylpolyglucoside sulfates, alkyl
polyethoxy carboxylates, and sarcosinates or mixtures thereof.
These anionic surfactants may be provided as salts with one or more
organic counterions, e.g, ammonium, or inorganic counteraions.
[0039] Exemplary cationic surfactants include quaternary ammonium
surfactants, such as lauryl trimethyl ammonium chloride, cetyl
trimethyl ammonium chloride, stearyl trimethyl ammonium chloride,
alkyl trimethyl ammonium chloride, distearyl dimethyl ammonium
chloride, cetyl trimethyl ammonium bromide, stearyl trimethyl
ammonium bromide, lanolin fatty acid aminopropylethyldimethyl
ammonium ethyl sulfate, stearyl trimethyl ammonium saccharine,
cetyl trimethyl ammonium saccharine, methacryloyloxyethyl trimethyl
ammonium chloride, and behenyl trimethyl ammonium methyl
sulfate.
[0040] Exemplary amphoteric surfactants include fatty acid
amidopropyldimethylamino acetic acid betaine,
alkyldimethylaminoacetic acid betaine,
N-acylaminoethyl-N-2-hydroxyethyl aminocarboxylate,
N-acylaminoethyl-N-carboxymethoxy ethyl aminocarboxylate, and
hydroxyalkyl (C12-14) hydroxyethyl sarcosine. Examples of the fatty
acid amidopropyldimethylaminoacetic acid betaine include
cocamidopropyl betaine, palm oil fatty acid
amidopropyldimethylaminoacetic acid betaine, lauramidopropyl
betaine, and ricinoleic acid amidopropyldimethylaminoacetic acid
betaine. Examples of the alkyldimethylaminoacetic acid betaine
include decyldimethylaminoacetic acid betaine,
lauryldimethylaminoacetic acid betaine, myristyldimethylaminoacetic
acid betaine, cetyldimethylaminoacetic acid betaine,
stearyldimethylaminoacetic acid betaine, oleyldimethylaminoacetic
acid betaine, behenyldimethylaminoacetic acid betaine, and coconut
oil alkyldimethylaminoacetic acid betaine. Examples of the
N-acylaminoethyl-N-2-hydroxyethyl aminocarboxylate include sodium
cocoamphoacetate and sodium cocoamphopropionate. Examples of the
N-acylaminoethyl-N-carboxymethoxy ethyl aminocarboxylate include
sodium cocoamphodiacetate, sodium cocoamphodipropionate, and sodium
lauroamphodiacetate.
[0041] The surfactant concentration level of the cleaning
composition may suitably be from about 0.5% to about 20% by weight,
based on the total weight of the composition. In one embodiment,
the surfactant concentration level is within the range of about 0.5
to about 15% by weight, or within the range of about 1 to about 10%
by weight, or within the range of about 1 to about 7% by
weight.
[0042] The composition includes at least one organic solvent.
Suitable organic solvents include one or more alcohols, glycols,
acetates, ether acetates and glycol ethers. Exemplary alcohols
include isopropanol, ethanol, and methanol. Exemplary glycols
include propylene glycol and ethylene glycol. Examples of ether
acetates include diethylene glycol monoethyl ether acetate, and
propylene glycol monomethyl ether acetate. Exemplary glycol ethers
include propylene glycol methyl ether, dipropylene glycol methyl
ether, tripropylene glycol methyl ether, propylene glycol
monopropyl ether, propylene glycol monobutyl ether, ethylene glycol
monobutyl ether, diethylene glycol monobutyl ether, diethylene
glycol methyl ether, and dipropylene glycol monopropyl ether. Other
organic solvents include n-methyl pyrrolidone, ketones, lactones
and terpenes such as d-limonene.
[0043] Mixtures of two or more organic solvents may be used.
Alternatively, a single organic solvent may be used. In one
embodiment, the organic solvent includes diethylene glycol
monobutyl ether.
[0044] As part of an effective cleaning composition, the organic
solvent concentration level may suitably be from about 0.5% to
about 20% by weight, based on the total weight of the composition.
In one embodiment, the organic solvent concentration level is
within the range of about 1 to about 15% by weight, or within the
range of about 1 to about 10% by weight, or within the range of
about 1 to about 3% by weight.
[0045] Other components may be added to the composition, such as
thickeners, gelling agents, fragrance, dispersants,
anti-redeposition agents, dyes and humectants for example.
[0046] The aqueous cleaning composition may be provided in a
concentrate that includes from about 1% to about 10% by weight of
at least one acid fluoride salt selected from ammonium bifluoride,
sodium bifluoride, potassium bifluoride, calcium fluorophosphates,
sodium fluorosilicates, and combinations of two or more thereof;
from about 2% to about 20% by weight of at least one mineral acid
adduct with urea; from about 1% to about 10% by weight at least one
surfactant; and from about 1% to about 10% by weight at least one
organic solvent.
[0047] In one embodiment, the concentrated aqueous cleaning
composition includes from about 4% to about 6% by weight of at
least one acid fluoride salt selected from ammonium bifluoride,
sodium bifluoride, potassium bifluoride, calcium fluorophosphates,
sodium fluorosilicates, and combinations of two or more thereof;
from about 2% to about 15% by weight of at least one mineral acid
adduct with urea selected from the adducts of urea with perchloric
acid; hydroiodic acid; hydrobromic acid; hydrochloric acid;
sulfuric acid; nitric acid; phosphoric acid and combinations of two
or more thereof; from about 1% to about 7% by weight at least one
surfactant; and from about 1% to about 3% by weight at least one
organic solvent.
[0048] The cleaning composition may be supplied in a concentrated
form or in a variety of diluted forms. Thus, the concentration of
the components in the supplied composition may vary widely.
Depending upon the application and the concentration of the
composition supplied, the user may dilute the composition prior to
use. The final concentration may be reached from a wide range of
supplied concentrations, using water to dilute the supplied
concentration, by using an appropriate dilution factor. For
example, the composition may be diluted with water in a
concentration of composition:water ratio of 1:1, 1:1.5, 1:2, 1:3,
1:4, 1:5, 1:6, 1:7, 1:8, 1:9, 1:10, or by using many other dilution
ratios.
[0049] In one aspect of the invention, a process for cleaning metal
surfaces is provided. The process includes cleaning the metal
surface by contacting the metal surface with the cleaning
composition described herein for a time sufficient to clean the
metal surface. The cleaning composition can be applied to the metal
surface using any of the contacting techniques known in the art.
For example, the cleaning composition may be applied by
conventional spraying or immersion methods.
EXAMPLES
Examples 1-7
[0050] Cleaning compositions containing varying amounts of ammonium
bifluoride and the adduct of hydrochloric acid with urea are
prepared as shown in Table 2. The amount of each ingredient for
Examples 1-7 is given in weight percent.
TABLE-US-00002 TABLE 2 Ex. Ex. Ex. Ex. Ex. Ex. Ex. Ingredient 1 2 3
4 5 6 7 Ammonium .sup. 0% 1.0% 3.0% 5.0% 7.0% 9.0% 10.0% bifluoride
(ABF) Urea:hydro- 10.0% 9.0% 7.0% 5.0% 3.0% 1.0% .sup. 0% chloride
(U:HCl) Diethylene glycol 2.0% 2.0% 2.0% 2.0% 2.0% 2.0% 2.0%
monobutyl ether Nonionic 1.0% 1.0% 1.0% 1.0% 1.0% 1.0% 1.0%
surfactant (Tomadol 900)* Water 87% 87% 87% 87% 87% 87% 87%
*ethoxylated alcohols, C9-11
[0051] The effectiveness of the cleaning compositions was tested
through evaluation of aluminum panels, which have been soiled and
then immersed in a diluted composition of the concentrated cleaning
compositions.
Formula for Lab Prepared Deposit Soil:
TABLE-US-00003 [0052] Ingredient Wt. % Deionized Water 51.3%
Bentone EW (Elementis Corp.) 1.5% Sodium Tripolyphosphate Low
Density 0.2% Minucil 5 (US Silica Corp.) 25.0% Aluminum Oxide # 19
(Graystar Corp.) 21.0% CW 5317 Black (Elementis Corp.) 1.0%
[0053] The water and bentone are stirred until gel formation,
approximately 30 minutes, using a regular overhead 3 bladed stirrer
(ETK Model) at approximately 2500 rpm. The remaining ingredients
are then added with good mixing to disperse.
[0054] One square foot of fin stock (aluminum fin stock from JW
Aluminum Corp.) is cut into a panel and cleaned using toluene
followed by acetone, and then rinsed with deionized water. The lab
prepared soil is applied to cover the entire one foot square
aluminum panel surface using a paint brush. The panel is baked
overnight in a 110.degree. C. lab oven. The panel is removed from
the oven and allowed to cool to room temperature. The panel is then
rinsed with water until the unattached soil is removed.
Testing of Formulations 1-7:
[0055] The effectiveness of each of the cleaning compositions of
Examples 1-7 was evaluated using the soiled aluminum fin stock
panel. Each composition was diluted 1 part to three parts water by
weight. Panels of the aluminum soiled with the lab prepared soil
were cut into coupons of approximately 1 inch.times.2 inches and
immersed in the diluted cleaner for 30 seconds. After 30 seconds
the coupons were immediately rinsed with deionized water.
[0056] FIG. 1 shows the results of the evaluation. The percent
clean was determined by using a grid count under 22.5.times.
magnification. The graph shows that the composition containing 10%
ABF (with no added urea hydrochloride) cleaned the surface 55%
clean. The composition containing 10% of the urea hydrochloride
adduct (with no ABF) had zero % cleaning. These results were
surprising, as it was expected that the % cleaning would increase
as the amount of ABF was increased.
Example 8-14
[0057] Cleaning compositions containing varying amounts of ammonium
bifluoride and the adduct of hydrochloric acid with urea are
prepared as shown in Table 3. The amount of each ingredient for
Examples 8-14 is given in weight percent.
TABLE-US-00004 TABLE 3 Ex. Ex. Ex. Ex. Ex. Ex. Ex. Ingredient 8 9
10 11 12 13 14 Ammonium 0.0% 1.0% 3.0% 5.0% 7.0% 9.0% 10.0%
bifluoride Urea:Hydro- 10.0% 9.0% 7.0% 5.0% 3.0% 1.0% 0.0% chloric
acid Diethylene glycol 2.0% 2.0 2.0 2.0 2.0 2.0 2.0 monobutyl ether
Amphoteric 2.0% 2.0% 2.0% 2.0% 2.0% 2.0% 2.0% surfactant (Amphosol
CA)** Nonionic 1.0% 1.0% 1.0% 1.0% 1.0% 1.0% 1.0% surfactant
(Tomadol 900) Water 85% 85% 85% 85% 85% 85% 85% **cocoamidopropyl
betaine 29-31%
[0058] The effectiveness of the cleaning composition was tested
through evaluation of aluminum panels, which have been oxidized and
are then immersed in the cleaning composition.
Preparation of Oxidized Panels:
[0059] Aluminum fin stock is cut into strips measuring 3 inches by
12 inches. The strips are cleaned with toluene, acetone and
deionized water and places in a 10% aqueous sodium chloride
solution. The aluminum strips are placed in the salt solution in a
closed container at 50.degree. C. oven for 24 hours. The strips are
then removed, and allowed to cool to room temperature and dry.
Testing of Formulations 8-14:
[0060] The effectiveness of each of the cleaning compositions of
Examples 8-14 was evaluated using the oxidized aluminum fin stock
strips. Each composition was diluted 1 part to three parts water by
weight. Strips of the oxidized aluminum were cut into coupons of
approximately 1 inch.times.2 inches and immersed in the diluted
cleaner for 1 minute. After 1 minute the coupons were immediately
rinsed with deionized water.
[0061] FIG. 2 shows the results of the evaluation. The percent
clean was determined by using a grid count under 22.5.times.
magnification. As can be seen from FIG. 2, the optimum performance
range is 5-7% by weight ammonium bifluoride in the concentrated
formulation for oxidation removal.
[0062] It is understood that the total percentage of acids may be
increased with increasing performance upon dilution for soil and
oxidation removal. However, with the compositions of the present
invention, it can be seen that lower concentrations of fluoride ion
are effective based on the average level of soils and considerably
safer to use from the point of manufacturing to the end user than
currently available bifluoride technologies using safe organic
co-acids.
Examples 15-18
[0063] Cleaning compositions containing adducts of various mineral
acids with urea are prepared as shown in Table 4. The amount of
each ingredient for Examples 15-18 is given in weight percent.
TABLE-US-00005 TABLE 4 Ex. Ex. Ex. Ex. Ingredient 15 16 17 18
Ammonium bifluoride 2.0% 2.0% 2.0% 2.0% Urea:HCl adduct 8.0% -- --
-- Urea:HNO.sub.3 adduct -- 8.0% -- -- Urea:H.sub.2SO.sub.4 adduct
-- -- 8.0% -- Urea:H.sub.3PO.sub.4 adduct -- -- -- 8.0% Diethylene
glycol monobutyl ether 2.0% 2.0% 2.0% 2.0% Nonionic surfactant 1.0%
1.0% 1.0% 1.0% (Tomadol 900) Water 85% 85% 85% 85%
Testing of Formulations 15-18:
[0064] The effectiveness of each of the cleaning compositions of
Examples 15-18 was evaluated using the lab prepared soiled aluminum
fin stock panel. Each composition was diluted 1 part to three parts
water by weight. Panels of the aluminum soiled with the lab
prepared soil were cut into coupons of approximately 1 inch.times.2
inches and immersed in the diluted cleaner for 30 seconds. After 30
seconds the coupons were immediately rinsed with deionized
water.
[0065] FIG. 3 shows the results of the evaluation on the lab
prepared soil surface. The percent clean was determined by using a
grid count under 22.5.times. magnification.
Examples 19-22 and Comparative Examples A-B
[0066] Cleaning compositions containing adducts of various mineral
acids with urea are prepared as shown in Table 5. The amount of
each ingredient for Examples 19-22 is given in weight percent.
TABLE-US-00006 TABLE 5 Ex. Ex. Ex. Ex. Ingredient 19 20 21 22
Ammonium bifluoride 5.0% 5.0% 2.0% 2.0% Urea:Hydrochloride adduct
5.0% -- -- -- Urea:Dihydrochloride adduct -- 11.0% -- --
Urea:Nitrate adduct -- -- 5.0% -- Urea:Dinitric Acid adduct -- --
-- 15.9% Diethylene glycol monobutyl ether 2.0% 2.0% 2.0% 2.0%
Nonionic surfactant 1.0% 1.0% 1.0% 1.0% (Tomadol 900) Amphoteric
surfactant 2.0% 2.0% 2.0% 2.0% (Amphosol CA) Water 85.0% 79.0%
85.0% 74.1%
Testing of Formulations 19-22--Oxidized Surface:
[0067] The effectiveness of each of the cleaning compositions of
Examples 19-22 was evaluated using the oxidized aluminum fin stock
strips. In addition, Comparative Example A containing about 10-13%
ammonium bifluoride, about 3-5% hydroxyacetic acid, and surfactants
(Calbrite) and Comparative Example B containing about 15-18%
hydrofluoric acid, 5-7% phosphoric acid and surfactants
(Acti-Brite) were also evaluated. Each composition was diluted 1
part to three parts water by weight. Strips of the oxidized
aluminum were cut into coupons of approximately 1 inch.times.2
inches. The oxidized coupons were immersed in the diluted cleaner
for different lengths of time and then immediately rinsed with
deionized water.
[0068] Table 6 shows the results of the evaluation on the oxidized
surface. The percent clean was determined by using a grid count
under 22.5.times. magnification.
TABLE-US-00007 TABLE 6 % Clean - Oxidized Example 10 sec. 15 sec.
30 sec. 45 sec. 19 10 80 85 90 20 10 75 90 95 Comp. A 10 -- 40 55
Comp. B 50 -- 95 100
Testing of Formulations 19-22--Double Oxidized Surface:
[0069] Strips of aluminum fin stock were prepared by immersing the
strips in a 10% sodium chloride solution at 50.degree. C. for 48
hours. This produced a much deeper layer of a dark oxide into the
aluminum metal strips of fin stock.
[0070] Each of the composition of Examples 19-22 and the
composition of Comparative Example B were diluted 1 part to three
parts deionized water by weight. The prepared strips of double
oxidized aluminum were immersed in the diluted cleaner for one
minute and then immediately rinsed with deionized water.
[0071] Table 7 shows the results of the evaluation on the double
oxidized surface. Reflectance was measured using a Photovolt Model
577-A reflectometer in accordance with ASTM D 4488-95.
TABLE-US-00008 TABLE 7 Example % Reflectance 19 85 20 90 21 90 22
95 Comp. Ex. B 100
[0072] The results obtained with the compositions prepared in
accordance with the present invention are very similar to the
results obtained with the hydrofluoric acid containing composition
of Comparative Example B.
Comparative Example C
[0073] A cleaning composition is prepared containing various
amounts of ammonium bifluoride in combination with the organic acid
hydroacetic acid.
TABLE-US-00009 TABLE 8 Ex. Ex. Ex. Ex. Ex. Ingredient C1 C2 C3 C4
C5 Ammonium bifluoride 2.0% 3.0% 5.0% 7.0% 10.0% Hydroacetic acid
8.0% 7.0% 5.0% 3.0% 0 Diethylene glycol monobutyl ether 2.0% 2.0%
2.0% 2.0% 2.0% Amphoteric surfactant 2.0% 2.0% 2.0% 2.0% 2.0%
(Amphosol CA) Nonionic surfactant 1.0% 1.0% 1.0% 1.0% 1.0% (Tomadol
900) Water 85% 85% 85% 85% 85%
[0074] The effectiveness of the cleaning compositions of
Comparative Example C was evaluated using oxidized aluminum fin
stock strips. Each composition was diluted 1 part to three parts
water by weight. Strips of the oxidized aluminum were cut into
coupons of approximately 1 inch.times.2 inches and immersed in the
diluted cleaner for 1 minute. After 1 minute the coupons were
immediately rinsed with deionized water.
[0075] FIG. 5 shows the results of varying the concentration of
ammonium bifluoride in a cleaning composition containing
hydroxyacetic acid. By comparing the results shown in FIG. 5 to
those of FIG. 2, it can be seen that a performance boost is
obtained by using a cleaning composition containing a safe
urea/mineral acid adduct in combination with ammonium bifluoride in
place of a cleaning composition containing a safe organic acid,
such as hydroacetic acid in combination with ammonium bifluoride.
Similar results are expected with the safe organic acid citric
acid.
[0076] While the invention has been explained in relation to
various embodiments, it is to be understood that various
modifications thereof will become apparent to those skilled in the
art upon reading this specification. Therefore, it is to be
understood that the invention provided herein is intended to cover
such modifications as may fall within the scope of the appended
claims.
* * * * *