CA1219119A - Composition for protecting metal surfaces against corrosion - Google Patents
Composition for protecting metal surfaces against corrosionInfo
- Publication number
- CA1219119A CA1219119A CA000430914A CA430914A CA1219119A CA 1219119 A CA1219119 A CA 1219119A CA 000430914 A CA000430914 A CA 000430914A CA 430914 A CA430914 A CA 430914A CA 1219119 A CA1219119 A CA 1219119A
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- CA
- Canada
- Prior art keywords
- component
- composition
- acid
- salt
- molar ratio
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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Classifications
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23F—NON-MECHANICAL REMOVAL OF METALLIC MATERIAL FROM SURFACE; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL; MULTI-STEP PROCESSES FOR SURFACE TREATMENT OF METALLIC MATERIAL INVOLVING AT LEAST ONE PROCESS PROVIDED FOR IN CLASS C23 AND AT LEAST ONE PROCESS COVERED BY SUBCLASS C21D OR C22F OR CLASS C25
- C23F11/00—Inhibiting corrosion of metallic material by applying inhibitors to the surface in danger of corrosion or adding them to the corrosive agent
- C23F11/08—Inhibiting corrosion of metallic material by applying inhibitors to the surface in danger of corrosion or adding them to the corrosive agent in other liquids
- C23F11/10—Inhibiting corrosion of metallic material by applying inhibitors to the surface in danger of corrosion or adding them to the corrosive agent in other liquids using organic inhibitors
- C23F11/12—Oxygen-containing compounds
- C23F11/124—Carboxylic acids
Abstract
ABSTRACT OF THE DISCLOSURE
An aqueous treating solution for protecting metal surfaces against corrosion which comprises the salt of at least one aliphatic carboxylic acid having 6 to 10 carbon atoms (component A), the salt of at least one polyoxycarboxylic acid having 6 to 8 carbon atoms (component B) and the salt of at least one aromatic monocarboxylic acid (component C), wherein the salt-forming cations of the components A, B and C acids are predominantly alkali metal ions, and wherein the molar ratio of component A to component B is from about 10 : 1 to 1 : 5, the molar ratio of component A to component C is from about 5 : 1 to 1 : 5 and the molar ratio of component B to component C is from about 5 : 1 to 1 : 10.
An aqueous treating solution for protecting metal surfaces against corrosion which comprises the salt of at least one aliphatic carboxylic acid having 6 to 10 carbon atoms (component A), the salt of at least one polyoxycarboxylic acid having 6 to 8 carbon atoms (component B) and the salt of at least one aromatic monocarboxylic acid (component C), wherein the salt-forming cations of the components A, B and C acids are predominantly alkali metal ions, and wherein the molar ratio of component A to component B is from about 10 : 1 to 1 : 5, the molar ratio of component A to component C is from about 5 : 1 to 1 : 5 and the molar ratio of component B to component C is from about 5 : 1 to 1 : 10.
Description
:L2~L9~9 Case No. P-11, 1 20 COP~POSITION FOR PPcOTECTING
~qETAL Sl:1RFACES AGAINST CORROSION
This invention relates to an improved composition for protecting metal surfaces against corrosion and, more particularly, relates to an improved aqueous treating fluid for protecting metal surfaces against corrosion during contact with aqueous liquids and/or during the storage of metal components after they have been treated with aqueous solutions, and to a concentrate composi~t~on for use in the preparation of such a~ueous treating fluid.
BACKGROUND OF THE INVENTION
_ In order to pro~ect metallic surfaces against corrosion when they are in contact with aqueous liquids or during storage after they have been treated or contacted with aqueous liquids, it is customary to add anticorrosion additives to the water or other aqueous solution which is in contact with the metallic surfaces. Frequently, the anticorrosion additive system utilized must provide protection for several different types of metals. For example, in recirculating heat exchanger systems or systems utili~ing aqueous hydraulic fluids, and the like, the components of which the system is made may be of steel and/or cast iron, as well as aluminum, copper, brass, zinc, or other metals or metal alloys, all of which must be protected against corrosion. In addition to the need to provide protection to a variety of different metals, the anticorrosion additives must be readily soluble and stable in water having various degress of hardness and must not be adversely effected ....
~2~
by either high or low temperatures. Desirably, such anticorrosion additives are effective at relatively low concentrations and must not be toxic or irritate the skin or have an unpleasant odor. Finally, such additives should not present any significant waste disposal problems~
Over the years, numerous aqueous systems have been developed for the protection of specific, individual metals against corrosion. In the case of steel and grey cast iron, for example, alkaline solutions of nitrites, particularly sodium nitrite, have been used~ Various organic substances have also been used to protect these materials, including benzoatesr borates, soaps an-d salts of amino acids or of sulfonamidocarboxylic acids, particularly the alkanolamine salts.
More specifically, European Patent specification 0,020,042 describes an anticorrosion agent which contains 5 - 20% by weight of an aliphatic monobasic acid of 8 - 20 carbon atoms, 0 - 4~ by weight of a lubricant, 10 - 35% by weight of an aromatic mono-or polycarboxylic acid and an amine which forms a water-soluble salt with the aliphatic and aromatic acids. U.S. Patent 3,573,225 describes an anticorrosion agent which contains 50 - 100 parts of a salt of a saturated carboxylic acid of 6 - 18 carbon atoms with an amine of 6 - 12 carbon atoms, 20 - 200 parts of an alkali metal benzoate and 1 - 50 parts of an alkanolamide obtained as a reaction product from ethanolamine and a saturated fatty acid of 6 - 18 ~2~9~
carbon atoms. Finally, German Offenlegungsschrift
~qETAL Sl:1RFACES AGAINST CORROSION
This invention relates to an improved composition for protecting metal surfaces against corrosion and, more particularly, relates to an improved aqueous treating fluid for protecting metal surfaces against corrosion during contact with aqueous liquids and/or during the storage of metal components after they have been treated with aqueous solutions, and to a concentrate composi~t~on for use in the preparation of such a~ueous treating fluid.
BACKGROUND OF THE INVENTION
_ In order to pro~ect metallic surfaces against corrosion when they are in contact with aqueous liquids or during storage after they have been treated or contacted with aqueous liquids, it is customary to add anticorrosion additives to the water or other aqueous solution which is in contact with the metallic surfaces. Frequently, the anticorrosion additive system utilized must provide protection for several different types of metals. For example, in recirculating heat exchanger systems or systems utili~ing aqueous hydraulic fluids, and the like, the components of which the system is made may be of steel and/or cast iron, as well as aluminum, copper, brass, zinc, or other metals or metal alloys, all of which must be protected against corrosion. In addition to the need to provide protection to a variety of different metals, the anticorrosion additives must be readily soluble and stable in water having various degress of hardness and must not be adversely effected ....
~2~
by either high or low temperatures. Desirably, such anticorrosion additives are effective at relatively low concentrations and must not be toxic or irritate the skin or have an unpleasant odor. Finally, such additives should not present any significant waste disposal problems~
Over the years, numerous aqueous systems have been developed for the protection of specific, individual metals against corrosion. In the case of steel and grey cast iron, for example, alkaline solutions of nitrites, particularly sodium nitrite, have been used~ Various organic substances have also been used to protect these materials, including benzoatesr borates, soaps an-d salts of amino acids or of sulfonamidocarboxylic acids, particularly the alkanolamine salts.
More specifically, European Patent specification 0,020,042 describes an anticorrosion agent which contains 5 - 20% by weight of an aliphatic monobasic acid of 8 - 20 carbon atoms, 0 - 4~ by weight of a lubricant, 10 - 35% by weight of an aromatic mono-or polycarboxylic acid and an amine which forms a water-soluble salt with the aliphatic and aromatic acids. U.S. Patent 3,573,225 describes an anticorrosion agent which contains 50 - 100 parts of a salt of a saturated carboxylic acid of 6 - 18 carbon atoms with an amine of 6 - 12 carbon atoms, 20 - 200 parts of an alkali metal benzoate and 1 - 50 parts of an alkanolamide obtained as a reaction product from ethanolamine and a saturated fatty acid of 6 - 18 ~2~9~
carbon atoms. Finally, German Offenlegungsschrift
2,614,234 discloses an aqueous treatment fluid for protecting metal surfaces against corrosion which contains a reaction product of an aliphatic carboxylic acid of 6 - 10 carbon atoms and a polyoxycarboxylic acid, such as gluconic acid or tartaric acid, with an alkanolamine. Although the foregoing, and other, systems have been found to be capable of reducing the corrosion of steel and cast iron, they have generally not been found to provide adequate protection for other metals.
It has been found, for example, that virtually the only materials which will provide corrosion protection for alumlnum are chromates or silicatesO In aqueous solutions, however, these materials are stable only at relatively high pH values and only in soft water. Similarlyt wi~h respect to zinc, in actual practice only chromates have been found to be useful for the prevention of corrosion. Although U.S. Patent 4,093,780 discloses that esters of thio~lycolic acid are suitable for preventing the formation of white rust on zinc, the poor water-solubility and strong, objectionable odor of these compounds has greatly limited their use.
Moreover, these materials have not been found to provide any significant corrosion protection for metals other than zinc.
In the case of copper and brass, anticorrosion agents based on mercaptobenzothiazole or benzotriazole have been found to be particularly 12~ 9 effective and are widely used. These materials, by tnemselves, have not been found to be effective anticorrosion agents for steel and, in many instances, when they are combined with materials which are effective in protecting steel aqainst corrosion, there is a substantial decrease in the protection which they provide for copper and brass.
Actually, very little has been published in regard to the protection of mutli-metal systems. A
review of this area is given by J. Webber entitled "The Inhibition of Corrosion in Industrial Cooling Systems", which appeared in Wirkstoff und Korrosion, Vol. 30 ( 1979 ), pages 713 - 722. According to this review, chromates are the only materials which provide significant corrosion protection for a number of different metals, including steel, cast iron, aluminum, copper, brass and zinc. Chromates, however, cannot be used in large amounts because of their toxicity and, recently, their use has been banned completely in many areas.
In addition to aqueous fluids for protecting metal surfaces against corrosion, oil emulsions have also been employed for protecting multi-metal systems.
These, however, have many disadvantages which have severaly restricted their use. For example, the emulsions tend to separate in hard water and, as a concéntrate, they are flammable. Additionally, the emulsions cannot be disposed of without going through expensive procedures to separate the oil portion from the aqueous portion.
3i,219~9 It is, therefore, an object of the present invention to provide an a~ueous solution for protecting metal surfaces against corrosion both while the aqueous solution is in contact with the metal surface and during the storage of the metal components after they have been treated with the aqueous solution.
A further object of the present invention is to provide an improved aqueous solution which will protect a number of different metals against corrosion.
A still further object of the present invention is or provide a concentrate composition from which the improved aqueous anticorrosion solutions may be prepared.
These and other ob~ects will become apparent to those of ordinary skill in the art from the description of the invention which follows.
SUMMARY OF THE INVENTION
Pursuant to the above objects, the present invention is directed to an aqueous treating solution for protecting metal substrates against corrosion which comprises the salt of at least one aliphatic carboxylic acid containing 6 - 10 carbon atoms (component A), the salt of at least one polyoxycarboxylic acid having 6 -8 carbon atoms (component B1, and the salt of at least one aromatic monocarboxylic acid (component C), wherein the salt-forming cations of components A, B and C are predominantly alkali metal ions and wherein the molar ratio of component A to component B is from about 10 : 1 to 1 : 5, the molar ratio of component A to component C is from about 5 : 1 to 1 : 5, and the molar ratio of component B to component C is from about 5 : 1 121g~19 to 1 : 10. ~urprisingly, it has been found that the foregoing combination of components in the aqueous treatment solution exhibit a synogistic effect in that significantly better corrosion protection results are obtained with this combination that are obtained using any one of the components along or in combination with only one further component. Further, it has been found . that, contrary to conventional practice in which organic acid corrosion inhibitors are utilized in the form of the alkanolamine salts of the acid in the aqueous treating solutions of the present invention, the alkali metal salts of these organic acids are significantly more effective.
DETAILED DESCRIPTION OF THE INVENTION
More specifically, in the practice of the present invention, the improved aqueous treating solution containing the components A, B and C, as have been described hereinabove, have a molar ratio of component A to component B of from about 10 : 1 to 1 : 5 and, preferably, from about 4 : 1 to 1 : 2. The molar ratio of component A to component C is from about 5 : 1 to 1 : 5 and, preferebly, from about 2 : 1 to 1 : 2. The molar ratio of component B to component C
is from about 5 : 1 to 1 : 10 and, preferably, from about 2 : 1 to 1 : 4.
The concentrations of the A, B and C
components in the aqueous treating solutions of the present invention may be varied over a relatively wide range, depending upon the manner in which the composition is utilized and the particular metal ~21g~
substrates which are to be protected against corrosion.
Typically, the three components Ar B and C are present in the aqueous treating solution in a total amount of from about 0.2 to about 4.0% by weight of the aqueous treating solution. Yreferably, these components are present in a total amount of about 0.5 to about 2.0% by weight of the aqueous treating solution. It will be appreciated~ however, that other amounts of these components may also be used and still obtain advantageous corrosion protection results.
As has been set forth hereinabove, component A is made up of the salt of at least one aliphatic carboxylic acid having 6 - 10 carbon atoms.
Particularly preferred compounds of this class are the salts of caprylic acid and/or ethylhexanoic acid.
Component ~ is made up of the salt of at least one polyoxycarboxylic acid having 6 - 8 carbon atoms.
Particularly preferred compounds of this class are the salts of gluconic acid and/or heptonic acid. Component C is made up of the salt of at least one aromatic monocarboxylic acid. A particularly preferred compound of this class is the salt of benzoic acid.
The salt-forming cations of these acid components are predominantly alkali metal ions.
Additionally, however, at least some of such salt-forming cations may also be ammonium ions. In this latter instance, however, it has been found that optimum corrosion protection results are achieved where the content of ammonium ions in the aqueous treating solution is not substantially in excess of about 20% of 12~ 9 the total cation content. Additionally, it is to be appreciated that although excellent corrosion protection results are obtained when the components A, B and C are formed of only one of the acid salts of the defined classes, in some instances it may be preferable to form one or more of the components of a combination of two or more of the acid salts of the class defined.
In addition to the A, B and C components which have been described hereinabove, the aqueous treating solutions of the present invention may also contain one or more non-ionic surfactants, preferably those having a turbidity point below about 30C. Such surfactants are water-soluble at low temperatures.
When the turbidity point of ~he surfactants is reached, the solutions begin to become cloudy and the foaming action of the surfactant solution is noticeably reduced. It has been found that by the addition of these non-ionic surfactants, the wetting of the metal surfaces is improved so that the treatment solutions are able to act even on moderately greasy or dirty metal substrates. Non-ionic surfactants which have been found to be particularly useful are the polyglycol ethers of fatty alcohols, fatty amines and polyamines, and polglycol esters of fatty acids, which have been reacted with ethyleneoxide and propyleneoxide.
Particularly advantageous surfactants of this type are the high molecular weight block polymers of polypropyleneglycol condensed with ethyleneoxide and the high molecular weight block polymers of polyethyleneglycol condensed with propyleneoxide.
~9~9 Sur~actants of this type are sold under the desiqnation Pluronic 52 by Wyandotte, U.S.A. Although various amounts of such surfactant may be used in the aqueous treating solutions of the present inventions, they are typically present in amounts from about 0.003 to about 0.5~ by weight of the total solution, with amounts within the range of about 0.01 to about 0.35~ by weight being particularly preferred.
The aqueous treating solutions of the present invention may also contain one or more additional conventional corrosion inhibitors for individual metals, provided such additional corrosion inhibitors are compatible with the other components in the treating solutions and d-o not have an adverse effect on the corrosion protection of any of the metal substrates which are contacted by the solution.
Typical of such other corrosion inhibitors which may be used are boric acid esters, salts of higher carboxylic acids, salts of amino acids, salts of sulfonomidocarboxylic acids and fatty acid alkanolamides. Where the treating solutions will be in contact with copper and/or brass components, the solutions may also advantageously contain mercaptobenzothiazoles, benzotriazole and their derivatives. Finally, the aqueous treating solutions of the present invention may also contain further additives to prevent or at least minimize attack on the solution and/or the treated metal substrates by micro-organisms. Typically, such additives may include biocides r such as phenol derivatives, formaldehyde or ~3L9~9 compounds which will evolve formaldehyde, triazines, quarternary ammonium compounds, and the like.
The total aqueous treating solutions will typically have a pH within the range of about 7 to 10 and, preferably, will have a pH within the range of about 8 to 9. The salts of the various organic acids or components A, B and ~ which are used in the present solutions may be simply prepared by mixing the organic acid with the appropriate alkali and water at temperatures of about 40 - 90C.
While the aqueous treating solutions may be prepared from solid salt mixtures, they are preferably formulated using a liquid concentrate which can be very easily diluted with water to~`form the final treating solution containing the components in the desired concentrations. Such concentrate componsitions, which form a part of the present inventionr will typically contain the components A, B and C in solution in water, in a total concentration of about 30 - 80% by weight.
Where a surfactant as described above is also included in the composition, such surfactant may be a part of the concentrate and is typically present in an amount within the range of about 0.5 to 10~ by weight of the concentrate, preferably from about 1 to about 4% by 2S weight.
~ y the use of the a~ueous treating solutions of the present invention, exceptional anticorrosion results are obtained on a wide variety of metal substrates. These solutions are found to provide corrosion protection for these metal substrates while ~Z:~9~1~
they are in contact with the solution. Additionally, corrosion protection is provided against residual water which may remain on the metal surfaces after they have been removed from the treating solutions.
In order that those skilled in the art may better understand the present invention and the manner in which it may be practiced, the following specific examples are given. In these examples, E~amples 9 through 11 are examples of the compositions of the present invention. Examples 1 through 8 and 12 are examples of solutions containing one or more of the individual components of Examples 9 through 11 but less than all of these components, or of compositions made up of sal~s other than the a~ ali metal sal~s.
In testing the various solutions of Examples 1 through 12, test sheets having the dimensions 100 x 20 x 1 millimeters of steel, aluminum, copper, brass (70/30 copper/zinc)~and zinc were weighed. These test sheets were then half-submerged in water of 22.4dH
(adjusted by means of clacium chloride additions) both with an without the addition of various corrosion inhibitor compositions. The test sheets were maintained half-submerged in the various solutions in beakers, covered with a watch glass, for 28 days at a temperature of 35C. Thereafter, the test sheets were removed from the solutions, rinsed and dried and again weighed. The inhibitory value of the various corrosion inhibitor additives was determined in accordance with the following formula:
1~9~
H - (M1 - M2) 100 Ml wherein Ml equals the loss in weight in water without an additive and M2 equals the loss in weight in the inhibited solution. The various solutions tested and the inhibitory values obtained are as follows:
~2~91~
Concen-Example tration Inhibitory Values No. Composition g/L Fe Al Zn Cu Brass 1 Water 22.4dH 0 0 0 0 0 2 Na caprylate 15 30 40 10 20 20
It has been found, for example, that virtually the only materials which will provide corrosion protection for alumlnum are chromates or silicatesO In aqueous solutions, however, these materials are stable only at relatively high pH values and only in soft water. Similarlyt wi~h respect to zinc, in actual practice only chromates have been found to be useful for the prevention of corrosion. Although U.S. Patent 4,093,780 discloses that esters of thio~lycolic acid are suitable for preventing the formation of white rust on zinc, the poor water-solubility and strong, objectionable odor of these compounds has greatly limited their use.
Moreover, these materials have not been found to provide any significant corrosion protection for metals other than zinc.
In the case of copper and brass, anticorrosion agents based on mercaptobenzothiazole or benzotriazole have been found to be particularly 12~ 9 effective and are widely used. These materials, by tnemselves, have not been found to be effective anticorrosion agents for steel and, in many instances, when they are combined with materials which are effective in protecting steel aqainst corrosion, there is a substantial decrease in the protection which they provide for copper and brass.
Actually, very little has been published in regard to the protection of mutli-metal systems. A
review of this area is given by J. Webber entitled "The Inhibition of Corrosion in Industrial Cooling Systems", which appeared in Wirkstoff und Korrosion, Vol. 30 ( 1979 ), pages 713 - 722. According to this review, chromates are the only materials which provide significant corrosion protection for a number of different metals, including steel, cast iron, aluminum, copper, brass and zinc. Chromates, however, cannot be used in large amounts because of their toxicity and, recently, their use has been banned completely in many areas.
In addition to aqueous fluids for protecting metal surfaces against corrosion, oil emulsions have also been employed for protecting multi-metal systems.
These, however, have many disadvantages which have severaly restricted their use. For example, the emulsions tend to separate in hard water and, as a concéntrate, they are flammable. Additionally, the emulsions cannot be disposed of without going through expensive procedures to separate the oil portion from the aqueous portion.
3i,219~9 It is, therefore, an object of the present invention to provide an a~ueous solution for protecting metal surfaces against corrosion both while the aqueous solution is in contact with the metal surface and during the storage of the metal components after they have been treated with the aqueous solution.
A further object of the present invention is to provide an improved aqueous solution which will protect a number of different metals against corrosion.
A still further object of the present invention is or provide a concentrate composition from which the improved aqueous anticorrosion solutions may be prepared.
These and other ob~ects will become apparent to those of ordinary skill in the art from the description of the invention which follows.
SUMMARY OF THE INVENTION
Pursuant to the above objects, the present invention is directed to an aqueous treating solution for protecting metal substrates against corrosion which comprises the salt of at least one aliphatic carboxylic acid containing 6 - 10 carbon atoms (component A), the salt of at least one polyoxycarboxylic acid having 6 -8 carbon atoms (component B1, and the salt of at least one aromatic monocarboxylic acid (component C), wherein the salt-forming cations of components A, B and C are predominantly alkali metal ions and wherein the molar ratio of component A to component B is from about 10 : 1 to 1 : 5, the molar ratio of component A to component C is from about 5 : 1 to 1 : 5, and the molar ratio of component B to component C is from about 5 : 1 121g~19 to 1 : 10. ~urprisingly, it has been found that the foregoing combination of components in the aqueous treatment solution exhibit a synogistic effect in that significantly better corrosion protection results are obtained with this combination that are obtained using any one of the components along or in combination with only one further component. Further, it has been found . that, contrary to conventional practice in which organic acid corrosion inhibitors are utilized in the form of the alkanolamine salts of the acid in the aqueous treating solutions of the present invention, the alkali metal salts of these organic acids are significantly more effective.
DETAILED DESCRIPTION OF THE INVENTION
More specifically, in the practice of the present invention, the improved aqueous treating solution containing the components A, B and C, as have been described hereinabove, have a molar ratio of component A to component B of from about 10 : 1 to 1 : 5 and, preferably, from about 4 : 1 to 1 : 2. The molar ratio of component A to component C is from about 5 : 1 to 1 : 5 and, preferebly, from about 2 : 1 to 1 : 2. The molar ratio of component B to component C
is from about 5 : 1 to 1 : 10 and, preferably, from about 2 : 1 to 1 : 4.
The concentrations of the A, B and C
components in the aqueous treating solutions of the present invention may be varied over a relatively wide range, depending upon the manner in which the composition is utilized and the particular metal ~21g~
substrates which are to be protected against corrosion.
Typically, the three components Ar B and C are present in the aqueous treating solution in a total amount of from about 0.2 to about 4.0% by weight of the aqueous treating solution. Yreferably, these components are present in a total amount of about 0.5 to about 2.0% by weight of the aqueous treating solution. It will be appreciated~ however, that other amounts of these components may also be used and still obtain advantageous corrosion protection results.
As has been set forth hereinabove, component A is made up of the salt of at least one aliphatic carboxylic acid having 6 - 10 carbon atoms.
Particularly preferred compounds of this class are the salts of caprylic acid and/or ethylhexanoic acid.
Component ~ is made up of the salt of at least one polyoxycarboxylic acid having 6 - 8 carbon atoms.
Particularly preferred compounds of this class are the salts of gluconic acid and/or heptonic acid. Component C is made up of the salt of at least one aromatic monocarboxylic acid. A particularly preferred compound of this class is the salt of benzoic acid.
The salt-forming cations of these acid components are predominantly alkali metal ions.
Additionally, however, at least some of such salt-forming cations may also be ammonium ions. In this latter instance, however, it has been found that optimum corrosion protection results are achieved where the content of ammonium ions in the aqueous treating solution is not substantially in excess of about 20% of 12~ 9 the total cation content. Additionally, it is to be appreciated that although excellent corrosion protection results are obtained when the components A, B and C are formed of only one of the acid salts of the defined classes, in some instances it may be preferable to form one or more of the components of a combination of two or more of the acid salts of the class defined.
In addition to the A, B and C components which have been described hereinabove, the aqueous treating solutions of the present invention may also contain one or more non-ionic surfactants, preferably those having a turbidity point below about 30C. Such surfactants are water-soluble at low temperatures.
When the turbidity point of ~he surfactants is reached, the solutions begin to become cloudy and the foaming action of the surfactant solution is noticeably reduced. It has been found that by the addition of these non-ionic surfactants, the wetting of the metal surfaces is improved so that the treatment solutions are able to act even on moderately greasy or dirty metal substrates. Non-ionic surfactants which have been found to be particularly useful are the polyglycol ethers of fatty alcohols, fatty amines and polyamines, and polglycol esters of fatty acids, which have been reacted with ethyleneoxide and propyleneoxide.
Particularly advantageous surfactants of this type are the high molecular weight block polymers of polypropyleneglycol condensed with ethyleneoxide and the high molecular weight block polymers of polyethyleneglycol condensed with propyleneoxide.
~9~9 Sur~actants of this type are sold under the desiqnation Pluronic 52 by Wyandotte, U.S.A. Although various amounts of such surfactant may be used in the aqueous treating solutions of the present inventions, they are typically present in amounts from about 0.003 to about 0.5~ by weight of the total solution, with amounts within the range of about 0.01 to about 0.35~ by weight being particularly preferred.
The aqueous treating solutions of the present invention may also contain one or more additional conventional corrosion inhibitors for individual metals, provided such additional corrosion inhibitors are compatible with the other components in the treating solutions and d-o not have an adverse effect on the corrosion protection of any of the metal substrates which are contacted by the solution.
Typical of such other corrosion inhibitors which may be used are boric acid esters, salts of higher carboxylic acids, salts of amino acids, salts of sulfonomidocarboxylic acids and fatty acid alkanolamides. Where the treating solutions will be in contact with copper and/or brass components, the solutions may also advantageously contain mercaptobenzothiazoles, benzotriazole and their derivatives. Finally, the aqueous treating solutions of the present invention may also contain further additives to prevent or at least minimize attack on the solution and/or the treated metal substrates by micro-organisms. Typically, such additives may include biocides r such as phenol derivatives, formaldehyde or ~3L9~9 compounds which will evolve formaldehyde, triazines, quarternary ammonium compounds, and the like.
The total aqueous treating solutions will typically have a pH within the range of about 7 to 10 and, preferably, will have a pH within the range of about 8 to 9. The salts of the various organic acids or components A, B and ~ which are used in the present solutions may be simply prepared by mixing the organic acid with the appropriate alkali and water at temperatures of about 40 - 90C.
While the aqueous treating solutions may be prepared from solid salt mixtures, they are preferably formulated using a liquid concentrate which can be very easily diluted with water to~`form the final treating solution containing the components in the desired concentrations. Such concentrate componsitions, which form a part of the present inventionr will typically contain the components A, B and C in solution in water, in a total concentration of about 30 - 80% by weight.
Where a surfactant as described above is also included in the composition, such surfactant may be a part of the concentrate and is typically present in an amount within the range of about 0.5 to 10~ by weight of the concentrate, preferably from about 1 to about 4% by 2S weight.
~ y the use of the a~ueous treating solutions of the present invention, exceptional anticorrosion results are obtained on a wide variety of metal substrates. These solutions are found to provide corrosion protection for these metal substrates while ~Z:~9~1~
they are in contact with the solution. Additionally, corrosion protection is provided against residual water which may remain on the metal surfaces after they have been removed from the treating solutions.
In order that those skilled in the art may better understand the present invention and the manner in which it may be practiced, the following specific examples are given. In these examples, E~amples 9 through 11 are examples of the compositions of the present invention. Examples 1 through 8 and 12 are examples of solutions containing one or more of the individual components of Examples 9 through 11 but less than all of these components, or of compositions made up of sal~s other than the a~ ali metal sal~s.
In testing the various solutions of Examples 1 through 12, test sheets having the dimensions 100 x 20 x 1 millimeters of steel, aluminum, copper, brass (70/30 copper/zinc)~and zinc were weighed. These test sheets were then half-submerged in water of 22.4dH
(adjusted by means of clacium chloride additions) both with an without the addition of various corrosion inhibitor compositions. The test sheets were maintained half-submerged in the various solutions in beakers, covered with a watch glass, for 28 days at a temperature of 35C. Thereafter, the test sheets were removed from the solutions, rinsed and dried and again weighed. The inhibitory value of the various corrosion inhibitor additives was determined in accordance with the following formula:
1~9~
H - (M1 - M2) 100 Ml wherein Ml equals the loss in weight in water without an additive and M2 equals the loss in weight in the inhibited solution. The various solutions tested and the inhibitory values obtained are as follows:
~2~91~
Concen-Example tration Inhibitory Values No. Composition g/L Fe Al Zn Cu Brass 1 Water 22.4dH 0 0 0 0 0 2 Na caprylate 15 30 40 10 20 20
3 Na gluconate 15 10 15 10 0 0
4 Na benzoate 15 70 20 10 0 0 6 Block polymer of 15 0 10 20 0 0 polypropylene glycol with ethy-lene oxide ~PLUR-ONIC* 67 from Wynadotte U.S.A.) 7 Na caprylate 9 30 40 20 20 20 Na gluconate 6 8 Na caprylate 8 80 60 30 20 20 Na benzoate 7 9 Na caprylate 6 90 85 85 40 40 Na gluconate 4 Na benzoate 5 As for Example No. 90 90 90 40 40 9 + PLURO~IC 62 2 11 As for Example No. 90 g0 90 99 99 10 + benzotriazole 12 as for Example No. - 95 70 70 80 80 11, but triethanol-amine salts * trade mark ~ 215~
While the above disclosure sets forth and describes various embodiments of the present invention, the compositions described are intended to illustrate but not limit the present invention. It will be understood that the specific embodiments described herein are subject to variation and modification by one skilled in the art having the benefit of the present . disclosure and .it is, therefore, intended that the present invention is to be limited solely by the following claims.
While the above disclosure sets forth and describes various embodiments of the present invention, the compositions described are intended to illustrate but not limit the present invention. It will be understood that the specific embodiments described herein are subject to variation and modification by one skilled in the art having the benefit of the present . disclosure and .it is, therefore, intended that the present invention is to be limited solely by the following claims.
Claims (16)
1. A composition for protecting metal surfaces against corrosion which comprises an aqueous solution comprising the salt of at least one aliphatic carboxylic acid having 6 to 10 carbon atoms (component A), the salt of at least polyoxycarboxylic acid having 6 to 8 carbon atoms (component B) and the salt of at least one aromatic monocarboxylic acid (component C), wherein the salt-forming cations of the acids of said components A, B and C are predominantly alkali metal ions and wherein the molar ratio of component A to component B is from about 10 : 1 to 1 : 5, the molar ratio of component A to component C is from about 5 : 1 to 1 : 5 and the molar ratio of component B to component C is from about 5 : 1 to 1 : 10.
2. The composition as claimed in Claim 1 wherein the molar ratio of component A to component B
is from about 4 : 1 to about 1 : 2, the molar ratio of component A to component C is from about 2 : 1 to 1 : 2 and the molar ratio of component B to component C is from about 2 : 1 to 1 : 4.
is from about 4 : 1 to about 1 : 2, the molar ratio of component A to component C is from about 2 : 1 to 1 : 2 and the molar ratio of component B to component C is from about 2 : 1 to 1 : 4.
3. The composition as claimed in Claim 1 wherein the components A, B and C are present in the composition in a total amount of from about 0.2 to 4%
by weight of the composition.
by weight of the composition.
4. The composition as claimed in Claim 2 wherein the components A, B and C are present in the composition in a total amount of from about 0.5 to 2%
by weight of the composition.
by weight of the composition.
5. The composition as claimed in Claim 1 wherein component A is selected from the salts of caprylic acid and ethylhexanoic acid, component a is selected from the salts of gluconic acid and heptanoic acid, and component C is the salt of benzoic acid.
6. The composition as claimed in Claim 1 wherein where is also contained at least one non-ionic surfactant having a turbidity point below 30°C.
7. The composition as claimed in Claim 6 wherein the surfactant is selected from block polymers of polypropylene glycol with ethylene oxide and block polymers of polyehtylene glycol with propylene oxide.
8. The composition as claimed in Claim 6 wherein the surfactant is present in the composition in an amount within the range of about 0.003 to 0.5% by weight of the composition.
9. The composition as claimed in Claim 8 wherein the surfactant is present in the composition in an amount within the range of about 0.01 to 0.3% by weight of the composition.
10. The composition as claimed in Claim 6 wherein there is also present at least one additional corrosion inhibitor selected from boric acid esters, salts of higher carboxylic acids, salts of amino acids, salts of sulfonamidocarboxylic acids, salts of fatty acid alkanolamides, mercapto benzothiazole, and benzothiazole.
11. The composition as claimed in Claim 10 wherein the solution has a pH within the range of about 7 to 10.
12. The composition as claimed in Claim 11 wherein the solution has a pH within the range of about 8 to 9.
13. An aqueous concentrate composition, suitable for the preparation of aqueous treating solutions for the protection of metal surfaces against corrosion, which concentrate comprises the salt of at least one aliphatic carboxylic acid having 6 to 10 carbon atoms (component A), the salt of at least one polyoxycarboxylic acid having 6 to 8 carbon atoms (component B), and the salt of at least one aromatic monocarboxylic acid (component C), wherein the salt-forming cations of the component A, B and C acids are predominantly alkali metal ions, and wherein the molar ratio of component A to component B is from about 10 : 1 to 1 : 5, the molar ratio of component A to component C is from about 5 : 1 to 1 : 5 and the molar ratio of component s to component C is from about 5 : 1 to 1 : 10 and the components A, B and C are present in a total amount of from about 30 to 80% by weight of the aqueous composition.
14. The concentrate composition as claimed in Claim 13 wherein there is also present at least one non-ionic surfactant having a turbidity point below 30°C, which surfactant is present in the concentrate composition in an amount of from about 0.5 to 10% by weight of the composition.
15. The concentrate composition as claimed in Claim 14 wherein the surfactant is selected from block polymers of polypropylene glycol with ethylene oxide and block polymers of polyethylene glycol with propylene oxide.
16. The concentrate composition as claimed in Claim 15 wherein the surfactant is present in an amount of from about 1 to 4% by weight of the aqueous concentrate composition.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE19823223940 DE3223940A1 (en) | 1982-06-26 | 1982-06-26 | TREATMENT LIQUID FOR CORROSION PROTECTION OF METAL SURFACES AND CONCENTRATE FOR THEIR PRODUCTION |
| DEP3223940.8 | 1982-06-26 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1219119A true CA1219119A (en) | 1987-03-17 |
Family
ID=6166954
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000430914A Expired CA1219119A (en) | 1982-06-26 | 1983-06-22 | Composition for protecting metal surfaces against corrosion |
Country Status (9)
| Country | Link |
|---|---|
| EP (1) | EP0099598A1 (en) |
| JP (1) | JPS5925977A (en) |
| AU (1) | AU561560B2 (en) |
| BR (1) | BR8303394A (en) |
| CA (1) | CA1219119A (en) |
| DE (1) | DE3223940A1 (en) |
| GB (1) | GB2122598B (en) |
| NZ (1) | NZ204711A (en) |
| ZA (1) | ZA834632B (en) |
Families Citing this family (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3521952A1 (en) * | 1985-06-20 | 1987-01-02 | Henkel Kgaa | AQUEOUS COMPOSITIONS FOR THE HILITE AND FLUX PROCESS AND THEIR USE |
| US4647392A (en) * | 1985-12-27 | 1987-03-03 | Texaco Inc. | Monobasic-dibasic acid/salt antifreeze corrosion inhibitor |
| US4851145A (en) * | 1986-06-30 | 1989-07-25 | S.A. Texaco Petroleum Nv | Corrosion-inhibited antifreeze/coolant composition |
| US5081333A (en) * | 1989-03-17 | 1992-01-14 | Mitsubishi Denki Kabushiki Kaisha | Electric discharge machining fluid with a fatty acid amide additive for rust inhibition |
| CA2051609A1 (en) * | 1990-10-01 | 1992-04-02 | Jeffrey M. Burns | Corrosion-inhibited antifreeze/coolant composition |
| DE69325828D1 (en) * | 1992-02-14 | 1999-09-09 | Atochem Elf Sa | Use to inhibit copper corrosion of a composition consisting of heptansoiuce or its derivatives and sodium tetraborate. |
| FR2687412B1 (en) * | 1992-02-14 | 1998-06-05 | Atochem Elf Sa | CARBOXYLIC ACID CORROSION INHIBITOR COMPOSITION AND ITS APPLICATION FOR INHIBITING CORROSION. |
| DE69220209T2 (en) * | 1992-04-06 | 1997-10-02 | Texaco Services Europ Ltd | Anticorrosive antifreeze |
| DE4323907A1 (en) * | 1993-07-16 | 1995-01-19 | Henkel Kgaa | Use of carboxylic acids in agents for treating metal surfaces |
| US5997763A (en) * | 1998-04-27 | 1999-12-07 | Shell Oil Company | Corrosion inhibiting antifreeze compositions containing various carboxylic acids |
| TW541354B (en) * | 1999-01-07 | 2003-07-11 | Otsuka Chemical Co Ltd | Surface treating agent and surface treating method for magnesium parts |
| US9700425B1 (en) | 2011-03-20 | 2017-07-11 | Nuvasive, Inc. | Vertebral body replacement and insertion methods |
Family Cites Families (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| BE480466A (en) * | 1943-11-04 | |||
| US2529178A (en) * | 1947-12-06 | 1950-11-07 | W H And L D Betz | Method for obtaining corrosion and tuberculation inhibition in water systems |
| FR1139139A (en) * | 1955-12-29 | 1957-06-25 | Anti-rust product | |
| GB855442A (en) * | 1957-05-22 | 1960-11-30 | Ici Ltd | Improvements in or relating to anti-rusting agents |
| GB838258A (en) * | 1958-03-14 | 1960-06-22 | Ici Ltd | Improvements in and relating to the prevention of corrosion in cooling systems |
| NL242077A (en) * | 1958-03-27 | |||
| NL121476C (en) * | 1959-11-10 | |||
| GB961409A (en) * | 1961-05-24 | 1964-06-24 | United States Borax Chem | Corrosion inhibitor compositions |
| US3405072A (en) * | 1966-01-05 | 1968-10-08 | Continental Can Co | Method of inhibiting corrosion of aqueous mediums by addition of lithium salts of organic acids |
| US3589859A (en) * | 1967-10-09 | 1971-06-29 | Exxon Research Engineering Co | Gluconate salt inhibitors |
| DE2614234C2 (en) * | 1976-04-02 | 1982-05-27 | Metallgesellschaft Ag, 6000 Frankfurt | Treatment liquid for the corrosion protection of metal surfaces and concentrate for their production |
-
1982
- 1982-06-26 DE DE19823223940 patent/DE3223940A1/en not_active Withdrawn
-
1983
- 1983-06-15 EP EP83200876A patent/EP0099598A1/en not_active Withdrawn
- 1983-06-22 CA CA000430914A patent/CA1219119A/en not_active Expired
- 1983-06-23 GB GB08317084A patent/GB2122598B/en not_active Expired
- 1983-06-24 BR BR8303394A patent/BR8303394A/en unknown
- 1983-06-24 ZA ZA834632A patent/ZA834632B/en unknown
- 1983-06-27 NZ NZ204711A patent/NZ204711A/en unknown
- 1983-06-27 AU AU16295/83A patent/AU561560B2/en not_active Ceased
- 1983-06-27 JP JP58115734A patent/JPS5925977A/en active Pending
Also Published As
| Publication number | Publication date |
|---|---|
| ZA834632B (en) | 1984-03-28 |
| GB2122598B (en) | 1985-07-10 |
| GB2122598A (en) | 1984-01-18 |
| AU561560B2 (en) | 1987-05-14 |
| GB8317084D0 (en) | 1983-07-27 |
| AU1629583A (en) | 1984-01-05 |
| JPS5925977A (en) | 1984-02-10 |
| BR8303394A (en) | 1984-02-07 |
| EP0099598A1 (en) | 1984-02-01 |
| NZ204711A (en) | 1986-02-21 |
| DE3223940A1 (en) | 1983-12-29 |
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