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Патент USA US2411676

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: Patented Nov. 26, 1946 I
2,411,676
UNITED . STATES PATENT OFFICE
2,411,676
CORROSION lNHI'BITING COMPOSITION
AND METHOD
Lloyd M. Burgliart, Darien, Conn, assignor to
U. S. Industria‘i Chemicals, Inc., New York,
N. Y., a corporation of Delaware
No Drawing. Application July 15, 1944,
Serial No. 545,203
9 Claims.
(01. 252-387)
,
1
This invention relates to corrosion inhibiting
ticularlvv aqueous solutions of ethylene glycol in
‘ compositions and methods of inhibiting corrosion
. which the corrosion inhibitor originally present
and particularly to products which can be stored
in the fresh solution has become ineffective so
that the solution may be reused with safety in the
- and shipped in a dry condition and are substan
' tially soluble in water and in aqueous solutions 5 cooling system.
of alcohols including glycols and the like, cus
tomarily employed as “antifreeze” in the cooling
A further object of the invention is the provi
‘ sion of a satisfactory method of inhibiting corro
sion in the cooling systems of internal combus
The problem of retarding corrosion in such
tion engines and a method of restoring solutions
cooling systems has occupied the‘attention of 10 in which inhibiting agents originally contained
many investigators, and numerous suggestions
therein have become ineffective.
have been made concerning compositions suit
Other objects and advantages of the invention
able for the purpose. While some of the pro
will be apparent as it is better understood by ref
erence to the following speci?cation which de->
posed ingredients are normally solid, the effective
compositions heretofore have been liquids such 15 scribes the preferred embodiments ofthe inven
systemslof internal combustion engines. _ '
' as the solution described in Letters Patent No.
tion.
'
‘
To aiford the advantages which are attained as
a result of the present invention, it is necessary
2,038,988 issued to me on April 28, 1936. The use
of such liquids involves serious problems of stor
age and transportation which have been accen
to provide a composition which meets certain re
tuated by prevailing conditions resulting from 20 quirements. The composition must consist of
solid materials capable of being packed, stored
'
One of the most perplexing of the questions in
and shipped in a dry condition. The ingredients
must be substantially'soluble in water and in
volved arises from the fact that the cooling ‘sys
terms of internal combustion engines as used for
aqueous solutions of alcohols including glycols
example in motor vehicles include surfaces of 25 and other polyhydric alcohols. The material
numerous different metals which are exposed to
must be stable chemically, that is to say, the in
the action of the circulating liquid such as water,
gredients must not react with each other either
usually including dissolved salts as impurities,
during storage or in use and thereby destroy the ‘
' or aqueous solutions of such alcohols as methyl,
effectiveness of the composition. The materials
‘ ethyl and iso-propyl, and ethylene glycol or other 30 used must lend themselves readily to proper
' polyhydric alcohols or mixtures thereof. The
grinding and mixing, must not segregate when
> metals so exposed may include brass, copper, sol
mixed, and they must not be unduly hygroscopic.
' ,
the
war.
.
'
der, aluminum, especially in the form of engine
head alloys, “Bohnalite,” steel and cast iron. All
- They must a?ord corrosion inhibiting e?ect over
a relatively extended period, 1. e., at least that of
, of these metals display different susceptibility to W a the average winter season, and must provide pro
.' corrosion under varying conditions and in the
tection for solder, aluminum, brass and copper,
presence of di?erent corrosion inhibiting agents.
as well as iron and steel. v'I'hey must aiiord a
An inhibitor in the case of one metal may have
liberal supply of reserve alkalinity to ensure a
the reverse e?ect on another. Hence the diilicul
reasonable period of e?ectiveness, and ?nally
ty of providing a composition which» affords a 40 they ‘must have no deleterious effect upon rubber
i
reasonable degree of protection for all of the
metals present and particularly one which can be
prepared, stored and shipped in a dry form to be
connections and gaskets and present no serious
problems of foaming.
\
No single solid chemical is known which pos
dissolved in the cooling liquid when required.
sesses all of the desirable features mentioned,
It is the object of the present invention to pro 45.. and thereis no reasonable probability that any
vide a dry inhibitor composition which can be
such-chemical exists or will be available. Hence
dissolved in water or ‘in aqueous solutions of any
‘the problem consists ‘in correlating the proper
of the commonly used‘ organic antifreeze liquids
ties of a number of chemical agents which, in
such as those heretofore mentioned to afford pro
combination, will provide corrosion inhibiting
tection against corrosion for the metals exposed
in the cooling system of an internal combustion
protection for the various metals present in the
cooling system and at the same time have the
engine.
other advantages hereinbefore speci?ed.
Another object 01' the invention is the provi
I have discovered that such compositions‘ may
sion of a solid composition which can be added as
be prepared from certain well known chemical
, a corrosion inhibitor to used cooling liquids, par 55 agents and that when such agents are combined,
2,41 1,676
3
.
.
4
understood» vthat the orthosilicates and silico
in substantially the proportions hereinafter set
forth, they will jointly and effectively protect the
various metals present in the cooling system from
corrosion. Furthermore, the materials speci?ed
fluorides may be used interchangeably or com
bined and that the nitrite may or may not be in
cluded in the composition.
are all solids, are all su?lciently soluble in water
and alcoholic solutions such as those mentioned,
Table II
Per cent
and together they have the other desirable prop
Alkali metal borate (calcined) __________ __ 40-75
erties which I have described.
Alkali metal chromate (neutral) or di
The compositions may vary somewhat with re- ‘
chromate
_
‘
10-35
spect to the ingredients employed as well as the 10 Alkali metal orthosilicate ______________ __ 5-10
proportions thereof which I utilize. As a basis
Alkali metal or aluminum alkali metal
of such compositions, I prefer to employ alkali
metal borates such ,as borax although boric acid
may be substituted for a'portion of the borax in
silico-?uoride ______________________ __
5-10
Alkali metal nitrite ___________________ __
5-14
Compositions such as those described have
an amount su?icient to adjust the pH of the so
lution of the composition within the limits here
been subjected to extended tests under corrosion
conditions comparable to those present in the
cooling systems of internal combustion engines
inafter disclosed,
The borates may be formed in situ by adding
an alkali metal compound such as the hydroxide
or carbonate to boric acid. With this material,
I combine an alkali meta1 chromate, either the
employing water and aqueous alcoholic solutions. ,
For the purpose of inhibiting corrosion, I
found it desirable to use approximately
ounce per gallon of liquid capacity of the
ing system. More or less could be used.
neutral chromate or the acid chromate such as
potassium chromate or potassium dichromate.
As an additional ingredient, I ?nd it desirable to
have
0.625
cool
The
amount indicated approximates ideal anti-cor
use an alkali metal orthosilicate such as sodium 25 rosion effect in respect to all of the metals nor
mally present in anengine cooling system, such
orthosilicate or an alkali metal or aluminum alkali
effect being the result of the combined action of
metal double salt of fluosilicic acid such asso
all of the ingredients used in respect to all of the
dium silico-?uoride or aluminum sodium silico
metals present.
fluoride. Either of these materials or both ortho
silicates and silico-iiuorides may be included in '30 Various changes may be made in the ingredi
ents and the ‘proportions thereof as described
the composition. Additional protection may be
without departing from the invention or sacri
obtained by adding to the composition an alkali
?cing the advantages thereof.
metal nitrite such as sodium nitrite, but the ni
I claim:
.
trite is not essential and may be omitted. In com- "
1. A dry composition capable of imparting cor
mercial compositions, a small amount of fluores- 35
rosion inhibiting characteristics to water and
cein is included merely as a coloring agent.
aqueous solutions of alcohols in the cooling sys
In the preparation of compositions such as
tems of internal combustion engines consisting
those described, the proportions may be varied
essentially of the following ingredients in the
within fairly wide limits. An essential consid
eration is, however, that in respect to acid in 49 weight percentage proportions of an alkali metal
borate about 40% to about 75%, a compound of
gredients such as silico-?uorides, boric acid and
the group consisting of alkali metal chromates
alkali metal dichromates, the proportion should
be such with respect to the alkalinity of the other
and dichromates about 10% toabout 35%, and
ingredients that the pH of a solution of the en
tire composition is not less than 7.5. This is par
ticularly true if nitrites are present in the com
position, since a lower pH is likely to cause de
a compound of the group consisting of alkali metal
orthosilicates, alkali metal silico-fluorides and
aluminum alkali metal silico-?uorides about 5%
to about 10%. .
um or potassium compounds may be used inter
changeably, The selection of ingredients with .
respect to alkali metal compounds depends pri
marily upon availability and other economic con
.
siderations.
'
2. A dry composition capable of imparting cor
rosion inhibiting characteristics to Water and
aqueous solutions of alcohols in the cooling sys
tems of internal combustion engines comprising
essentially the following ingredients in the weight
percentage proportions of an alkali metal borate
about 40% to about 75%, a compound of the
group consisting of alkali metal chromates and
composition of .nitrites. In general, either sodi-.
'
As‘examples of suitable compositions, the fol
lowing table affords desirable relative proportions
of the various ingredients which may be combined
dichromates about 10% to about 35%, a com
to a?ord satisfactory inhibiting compositions '
pound of the group consisting of alkali metal
orthosilicates, alkali metal silica-fluorides and
aluminum alkali metal silica-?uorides about 5%
which dissolve sumciently in water and in aque
ous solutions of alcohols including glycols:
60 to about 10%, and an alkali metal nitrite about
Table I
5% to about 14%, the amounts of said ingredients
I
II
III
IV
70. 75
61. 80
62. 20
72. 95
or potassium dichromate.-. 20.10
17.50
17. 65
17.00
17.00
7. 95
_____ ..
5. 00
5.00
, Alkali metal borate (calcined)
Potassium chromate, neutral,
Sodium orthosilicate _______ ._
,
9. l0
V
(i0. 10
,
Sodium sllico-?uorido or alu
minum sodium sillco-?uo
ride ____________________________________ , _
Sodium nitrite ______________ . _' .... _.
Fluorescein ________________ ..
. 05
7. 30
12. 70
12.80
. 05
. 05
5. O0
_____ _.
being selected within the stated ranges so as to
5. 00
12. 85
. 05
. 05
100.00 100. 00 100.00 100. 00
100.00
As indicative of the available range of propor
total approximately 100%.
3. A dry composition capable of imparting cor
65 rosion inhibiting characteristics to Water and
‘
aqueous solutions of alcohols in the cooling sys
tems of internal combustion engines consisting
essentially of the following ingredients in the
weight percentage proportions of sodium borate
70 about 40% to about ‘75%, sodium chromate about
10% to about 35%, and a compound of the group
consisting of alkali metal orthosilicates, alkali
metal silico-?uorides and aluminum alkali metal
tions to produce effective compositions, the fol
silico-iluorides about 5% toabout 10%.
_
lowing table indicates the general limits, it beingI 75 4. A dry composition capable of imparting cor
2,411,070 I
rosion inhibiting characteristics to water and
aqueous solutions of alcohols in the cooling sys
tems of internal combustion engines consisting
essentially of the following ingredients ‘in the
weight percentage proportions of sodium s'borate
about 40% to about 75%, sodium chromate about
10% to about 35 %', and sodium orthosilicate about
5% to about 10%.
' -
5. A dry composition capable of imparting cor
rosion inhibiting characteristics to water and -
aqueous solutions of alcohols in the cooling sys'-'
tems of internal combustion engines comprising
essentially the following ingredients in the weight
percentage proportions of sodium borate about
6
of alkali metal chromates and dichromates about _
10% to ‘about 35%; a compound of the group
consisting oi’ alkali metal orthosilicates, alkali
metal silica-?uorides and aluminum alkali metal
silico-?uorides about 5% to about 10%, and an
alkali metal nitrite‘ about 5% to about 14%,
the amounts of said. ingredients being selected
within the stated ranges so as to total approxi
mately 100%.
.I
-
_
8. The method of restoring the corrosion in
hibiting properties‘ of spent aqueous alcoholic
solutions employed ‘as anti-freezev in the cooling
system of internal combustion engines which
consists of adding to such spent solutions a com
‘ 40% to about 75%, sodium chromate about ‘10% 15 position consisting essentially of the'following
to about 35%, sodium orthosilicate about 5% to
about 10%, and sodium nitrite about 5%‘ to about
14%, the amounts of said ingredients being se
ingredients in the weight percentage proportions
of an alkali metal borate about 40% to about
u 75%, a compound; of the group consisting of
lected within the stated ranges so as to total ' alkali metal chromates and dichromates about
'
20 10% to about 35%, and a compound of the group
- approximately 100%.
_ 6. The method of inhibiting corrosion in the ‘ '
consisting of alkali metal orthosilicates, alkali
metal silico-?uoride's and aluminum alkali metal
which consists of circulating therein water and
silico-?uorides about 5% to about 10%.
aqueous solutions of alcohols containing in solu
9. The method of restoring the corrosion .in
tion a composition consisting essentially of the 25 hibiting properties of spent aqueous alcoholic
cooling system of internal combustion engines
following ingredients in the weight ‘percentage
proportions of an alkali metal borate about 40%
' solutions employed as anti-freeze in the cooling
system'of internal combustion engines which con
to about 75%, a_ compoundof the group consist
sists of adding to such spent solutions a composi
ing of alkali metal chromates and dichromates
tion comprising essentially the‘following in- r
about 10% to about 35%, and a compound of 30 gredients in the weight percentage proportions
the group consisting of alkali metal'orthosili
of an alkali borate about 40% to about 75%, a
cates, alkali-metal silica-?uorides and aluminum compound of the group consisting of alkali metal
alkali metal silico-?uorides about 5% toabout
chromates and dichromates about 10% to about
10%.
~
35%, a compound oi’ the group consisting of alkali ,
7. The method of inhibiting corrosion in the 35 metal orthosilicates, alkali metal silico-?uorides
cooling system of internal combustion engines‘
which consists of circulating therein water and.
aqueous solutions of alcohols containing in solu- ‘
tion a composition comprising essentially the fol
lowing ingredients in the weight percentage pro
portions of an alkali metal borate about 40% to
about 75%, a compound of the group consisting
and aluminum alkali metal silica-?uorides about
5% to about 10%, and an alkali‘metal nitrite
about 5% to about 14%, the amounts of said
ingredients being selected within the stated ranges
so as to total approximately 100%.
‘
LLOYD . M. BURGHART.
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