JP2565500B2 - Method for producing water-soluble metal-containing composition for high temperature oxidation prevention of metallic material - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for producing a water-soluble metal-containing composition which prevents oxidation of metal materials at high temperatures (except for oxidation prevention in resistance welding). Is.

[Prior Art] As a means for improving the high temperature oxidation resistance of a metal material,
For example, in the case of stainless steel, methods of increasing the content of Al and Si in the alloy are known, but these methods impair the mechanical properties (workability) and weldability of stainless steel. There are drawbacks.

In addition, as a measure for preventing oxidation other than the above, there is known a method of forming an antioxidant film on the surface of a metal material.
For example, JP-A-60-56078 and JP-A-61-87877.
Japanese Patent Laid-Open Publication No. 2003-242242 discloses an antioxidant method using a metal alkoxide. In these methods, a metal alkoxide solution is applied to the surface of a metal material, or a solution obtained by previously hydrolyzing an oxide sol is applied, and then heat-treated to form an oxide film on the surface of the metal material. However, this oxide film has problems such as cracking on the surface and pinholes, and it cannot be said to be a sufficient method for improving the oxidation resistance. Further, a method of forming an oxide sol or the like using a metal salt and forming an oxide film by heating after coating is also known, but this method also has the same drawbacks as the above, and It has also been pointed out that the metal material is attacked by the remaining anions.

[Problems to be Solved by the Invention] The present invention has been made in view of the above circumstances, and an object thereof is to form an excellent oxidation resistant coating on a metal material, Water-soluble metal-containing composition capable of forming an oxidation resistant coating capable of preventing oxidation of a metal material by a liquid continuous coating formed by simply preventing the material from being oxidized at high temperature The present invention is intended to provide a manufacturing method of.

[Means for Solving Problems] The production method of the present invention which has been able to achieve the above-mentioned object is one or more metal alkoxides selected from the group consisting of B, Al, Ga and In. , One or more amino alcohols, and a carboxylic acid are sequentially or simultaneously heated in the presence or absence of an organic solvent, which is a characteristic thereof.

The metal alkoxide used in the present invention is particularly preferably a compound represented by the general formula M (OR) ₃ (wherein M is B, A
l, Ga or In, or R represents a lower alkyl group)
Particularly preferred as the amino alcohols are the metal alkoxides represented by, and one or more of ethanolamines represented by the following general formula, (B) R ₁ N (CH ₂ CH ₂ OH) ₂ (c) N (CH ₂ CH ₂ OH) ₃ [wherein R ₁ and R ₂ are C _n H _{2n + 1} (n is 0, ₁ to 4; Represents an integer)] Particularly preferred as the carboxylic acid is a lower aliphatic carboxylic acid. Amino alcohol 0.05 to 4 relative to 1 mol of the metal element in the metal alkoxide.
A water-soluble metal-containing composition which is particularly excellent in high-temperature oxidation resistance with respect to a metal material can be obtained by heating and reacting moles of the carboxylic acid with 0.05 to 4 moles.

[Operation] In order to prevent the oxidation of the metal material at high temperature, the present inventors have
As a result of various studies on various drugs and compounding agents, as described above, one or more metal alkoxides selected from the group consisting of B, Al, Ga and In and one of amino alcohols
When a water-soluble metal-containing composition obtained by heating and reacting one or more kinds and carboxylic acid in the presence or absence of an organic solvent is applied to the surface of a metal material and heat-treated, the surface of the metal material is treated. An excellent oxidation resistant coating that is free from cracks and has no pinholes is formed, which exhibits an excellent antioxidant function even at high temperatures, and the metal-containing composition is simply applied to a metal material. Just to form a uniform liquid continuous film on the surface,
It has been found that this exhibits an excellent antioxidation effect on metal materials at 100 to 500 ° C, and can be easily removed by washing with water thereafter.

The metal alkoxide selected from the group consisting of B, Al, Ga and In used in the present invention is a lower metal alkoxide (especially having a carbon number of 1 to 1).
4) General formula M (OR) ₃ having an alkyl group (where M is B,
Preferred examples include metal alkoxides represented by Al, Ga or In, and R is an alkyl group, and preferred amino alcohols are those represented by the general formula (B) R ₁ N (CH ₂ CH ₂ OH) ₂ , (c) N (CH ₂ CH ₂ OH) ₃ [wherein R ₁ and R ₂ are C _n H _{2n + 1} (n is _{0, 1} to 4 Is most preferable, and the preferred carboxylic acid is an aliphatic carboxylic acid having 1 to 4 carbon atoms.

The preferable mixing ratio of the above-mentioned three kinds of components is 1 or 2 of amino alcohol to 1 mol of metal element in 1 or 2 or more kinds of metal alkoxide selected from the group consisting of B, Al, Ga and In. The total blending amount of at least one species is 0.05 to 4 mol, and the blending amount of carboxylic acid is 0.05 to 4 mol. Within this range, the high-temperature antioxidant function for the metal material becomes very excellent. When the concentration of amino alcohol is more than 4 mol, carbonization of the organic matter at high temperature becomes remarkable, while when it is less than 0.05 mol, the oxidation resistant coating formed by the heat treatment tends to be cracked or pinholes. Even when a liquid continuous film is formed to prevent oxidation, if it exceeds 4 mol, it becomes difficult to wash it off with water after completion of the operation due to carbonization of the organic matter, and if it is less than 0.05 mol, the antioxidant effect tends to be insufficient.

If the amount of the carboxylic acid is less than 0.05 mol, cracks are likely to occur in the oxidation resistant coating, and if it exceeds 4 mol, the metal material surface may be corroded. Even when a liquid continuous film is formed to prevent oxidation, if it exceeds 4 mol, the surface of the metal material may be corroded, and if it is less than 0.05 mol, a sufficient antioxidant effect cannot be obtained.

Among the combinations of two or more selected from the group consisting of B, Al, Ga and In, when the boron alkoxide is used as one metal alkoxide, the high temperature antioxidation effect on the metal material becomes very excellent, When the amount of boron alkoxide in the total metal alkoxide is 0.5 to 0.995 mol and the total amount of other metal alkoxide is in the range of 0.005 to 0.5 mol,
The effect is the best. This tendency is true both when the oxidation resistant coating is formed to prevent the oxidation and when the liquid continuous coating is formed to prevent the oxidation.

Particularly preferable ethanolamine among amino alcohols is represented by the general formulas (a) to (c) as described above, but the antioxidant effect becomes smaller in the order of (a), (b) and (c), and The larger the molecular weight, the smaller the effect.

As for the carboxylic acid, the lower aliphatic carboxylic acid is the most suitable one as described above. However, since the one having a smaller number of carbon atoms exhibits a superior antioxidant effect, it usually has 1 to 1 carbon atoms. The aliphatic carboxylic acid of 4, specifically, formic acid, acetic acid, propionic acid or the like is used.

Among the metal alkoxides used in the present invention, boron alkoxide which is particularly preferred is an alkoxide having 1 to 4 carbon atoms, and among them, alkoxide having 1 and 2 carbon atoms, boron methoxide (trimethyl borate),
When boron ethoxide (triethyl borate) is used, the highest antioxidant effect is exhibited, followed by boron propoxide and boron butoxide in that order.

As the metal alkoxide of the other three kinds of elements Al, Ga, and In other than the boron alkoxide, an alkoxide having 1 to 4 carbon atoms can be mentioned.

Even when one of the above-mentioned metal alkoxides is selected, the best antioxidant effect is obtained when boron alkoxide is used, followed by In, Ga and Al metal alkoxides in that order.

The metal-containing composition for high temperature oxidation obtained by the present invention is prepared by mixing the above metal alkoxide, amino alcohol and carboxylic acid in the above mixing ratio, or dissolving or suspending in an alcohol or an organic solvent compatible with the alcohol. And a heating reaction. The obtained metal-containing composition may be used as an antioxidant composition as it is in an organic solvent solution, or may be used after removing the contained organic solvent.

The reaction temperature is not particularly limited, but usually 120 ° C or lower,
It is preferably selected from the range of 60 to 100 ° C. The reaction temperature can be adjusted at the reflux temperature by changing the type of solvent used. For the end point of the reaction, the infrared absorption spectrum of the reaction product was measured, and the absorption band at the wavelength of 1300 to 1800 cm ⁻¹ (amide I absorption band C = 0 stretching vibration, amine NH ₂ or NH bending vibration, amide II absorption band NH modulation Confirmed by a change in the absorption band of angular vibration. Changes in the absorption band in this region as the reaction progresses are as shown in FIGS. 1 to 7, for example. The composition capable of exhibiting the high temperature oxidation preventing function with respect to the metal material may have the absorption shown in any of FIGS. 1 to 7, but preferably has the absorption shown in FIGS. That is, since the absorption band at 1660 cm ^-1 (amide I absorption band C = 0 stretching vibration) can be clearly confirmed as a shoulder peak of the absorption band at 1590 cm ^-1 (amine NH ₂ bending vibration), 1590 cm ^-1
It is in the range until the ratio of the absorption band peak heights of 1530 cm ^-1 (amide II absorption band NH bending vibration) becomes 1: 1. First
In the reaction progressing state as shown in the figure, it may attack the surface of the metal material, and as shown in FIG. 7, 1590 cm ^-1 and 15
In the case where the peak height of the absorption band at 30 cm ^-1 is reversed, the wettability to the metal material surface is deteriorated, and as a result, the antioxidant effect is poor.

This reaction is promoted by using formamide, N-methylformamide, N, N-dimethylformamide, N, N-diethylformamide, acetamide, N-methylacetamide or the like as an organic solvent. For example, as shown in FIGS. 1 to 7, when N, N-dimethylformamide is used, compared to when isopropyl alcohol is used,
A reaction product having a similar infrared absorption spectrum can be obtained by a reaction for about time, and the time can be shortened by about 10 times. By utilizing such a phenomenon, the reaction time can be arbitrarily controlled by appropriately mixing and using these amide-based organic solvent and other organic solvent.

The composition having an infrared absorption spectrum shown in FIGS. 1 to 7 obtained by carrying out a reaction using an organic solvent that promotes such a reaction exerts a very excellent antioxidant effect on a metal material.

These absorption bands in the wave number range of 1300 to 1800 cm ^-1 show some shifts depending on the type of metal compound, ethanolamines or carboxylic acid, but changes with the progress of the reaction and oxidation prevention of the metal material against it The effect correlations are almost unchanged.

Further, in carrying out the present invention, an ethanolamine salt obtained by previously reacting a metal alkoxide with ethanolamine may be reacted with a carboxylic acid, and an ester or amide compound obtained by previously reacting etalamine with a carboxylic acid may also be used. It is possible to obtain a composition having an antioxidant effect similar to the above, by reacting with a metal alkoxide or by using a product obtained by previously reacting a boron alkoxide with a carboxylic acid.

When the metal-containing composition obtained as described above is used as a high temperature antioxidant, the composition is calculated in terms of metal oxide.
The concentration is adjusted with an organic solvent so that the concentration is 0.5 to 30% by weight, more preferably 5 to 20% by weight. If it is less than 0.5% by weight, the film becomes too thin to obtain a sufficient antioxidation effect, while if it exceeds 30% by weight, the solution becomes highly viscous, making it difficult to perform coating work and making it difficult to form a uniform film. Become.

After applying the metal-containing composition to a metal material,
When heat treatment is performed at 500 to 800 ° C., preferably 600 to 800 ° C., an oxide film is formed on the surface of the metal material, and this film exhibits the function of preventing the oxidation of the metal material. The oxide film can be formed in the atmosphere.

In addition, if the metal-containing composition is applied to a metal material to form a liquid continuous film, oxidation of the metal material at 100 to 500 ° C can be prevented. In this case, carbonization of the organic matter progresses as the temperature increases, but the remaining coating after the operation is not only liquid but remains carbonized, but can be easily removed by washing with water. When the amount of carbides is large, if the surface of the metal material is heated to 100 ° C. or higher, washing with water or hot water makes it easier to remove the residue.

Thus, the metal-containing composition obtained by the present invention is
Exhibits antioxidant effect in a wide temperature range from low temperature to high temperature for metal materials, and 100-500 as liquid coating
When it is used in the range of ° C, it has a property that it can be removed only by washing the composition coated on the surface of the metal material with water after the heat treatment of the metal material.

Furthermore, in the production of this metal-containing composition, the progress of the reaction can be controlled by measuring an infrared absorption spectrum, and formamide, N, N-
By using an amide-based solvent such as dimethylformamide, the reaction can be promoted and the production time can be shortened.

Examples of the metal material to which the present invention is applied include various metal materials such as stainless steel, aluminum, and iron / steel that generate oxide scale at high temperatures.

[Examples] The present invention will be described in more detail with reference to Examples below.
The present invention is not limited by the examples below.

Example 1 Boron ethoxide (triethyl borate) (content of 97% or more)
(Tokyo Kasei Co., Ltd.) 500 ml (B ₂ O ₃ equivalent 1.5 mol) and Mono 2nd
Grade-butoxy aluminum diisopropoxide (Al content
12.4% by weight) (Kawaken Fine Chemical Co., Ltd.) 10 g (Al ₂ O ₃
0.023 mol), 450 g (7.4 mol) of monoethanolamine and 150 g (3 mol) of formic acid are added to isopropyl alcohol.
After dissolving or suspending in 400 ml, the mixture was heated with stirring at 75 ° C. The reaction solution was sampled every 5, 9, 15, 21, 33, 46, and 58 hours after the start of the reaction, and the infrared absorption spectrum was measured. Each infrared absorption spectrum is shown in FIGS.

The seven types of collected compositions had an oxide content of 18
The concentration was adjusted with isopropyl alcohol to give a coating liquid. Apply this coating solution to stainless steel (SUS 30
4) to form a liquid continuous film, one is 300 ℃
After 30 minutes of heat treatment, the remaining liquid film and carbide were removed by washing with water, and the degree of oxidation of the stainless steel surface was observed.
The results are shown in Table 1.

The other one was subjected to heat treatment at 600 ° C. for 30 minutes to form an oxide film and then held at 1000 ° C. for 5 hours, and after cooling, the oxidation state of the surface was observed. The results are shown in Table 2.

Example 2 The same operation was performed except that boron methoxide (boron trimethyl) (content of 97% or more) (manufactured by Tokyo Kasei Co., Ltd.) 330 ml (1.5 mol in terms of B ₂ O ₃ ) was used instead of boron ethoxide in Example 1. When an infrared absorption spectrum was measured after about 70 hours, a composition having a spectrum similar to that shown in FIG. 2 was obtained. The concentration of this composition was adjusted with isopropyl alcohol so as to be 15% by weight in terms of oxide, and a performance test as an antioxidant was conducted in the same manner as in Example 1. Samples Nos. Results similar to .2 were obtained.

Example 3 A heating reaction was carried out in the same manner as in Example 1 except that isopropyl alcohol as an organic solvent was replaced with N, N-dimethylformamide, and an infrared absorption spectrum after 2 hours was measured. A composition showing a spectrum was obtained.

The concentration of this composition was adjusted with isopropyl alcohol so as to be 15% by weight in terms of oxide, and a performance test as an antioxidant was conducted in the same manner as in Example 1.
Results similar to those of the sample Nos. 2 to 3 in Table 2 were obtained.

Example 4 Boron methoxide (content of 97% or more) (manufactured by Tokyo Kasei) 33
0 ml (1.5 mol B ₂ O ₃ equivalent) and diethanolamine 525 g (5
Mol) and 180 g (3 mol) of acetic acid were dissolved or suspended in 500 ml of N-methylformamide and heated to reflux with stirring. The reaction was completed in about 2 hours, and the infrared absorption spectrum was measured. As a result, a composition showing a spectrum similar to that shown in FIG. 4 was obtained.

The concentration of this composition was adjusted to 10% by weight in terms of oxide with ethyl alcohol, and a performance test as an antioxidant was conducted in the same manner as in Example 1. Antioxidation results similar to those of .2-3 were obtained.

Example 5 Indium isopropoxide 146 g (0.5 mol), monoethanolamine 137 g (2.2 mol) and propionic acid 1
50 g (2 mol) were suspended or dissolved in 600 ml of ethyl alcohol and heated with stirring. The reaction was completed in about 10 hours, and the infrared absorption spectrum was measured. As a result, a composition having a spectrum close to that shown in FIG. 1 was obtained.

The concentration of this composition was adjusted with ethyl alcohol so as to be 15% by weight in terms of oxide, and a performance test as an antioxidant was conducted in the same manner as in Example 1. The sampling test Nos. Results similar to those of .1 were obtained.

Example 6 Aluminum isopropoxide (A1 content 13.2% by weight)
204 g (Al ₂ O ₃ equivalent 0.5 mol), diethanolamine 158 g
(1.5 mol) and 150 g (3.1 mol) of formic acid were dissolved or suspended in isopropyl alcohol and heated to reflux with stirring. After the reaction was completed for 10 hours and the infrared absorption spectrum was measured, a composition showing a spectrum similar to that shown in FIG. 4 was obtained.

The concentration of this composition was adjusted with isopropyl alcohol to be 15% by weight in terms of oxide, and a performance test as an antioxidant was conducted in the same manner as in Example 1.
The results were almost intermediate between the sample Nos. 1 and 2 in Table 2.

Example 7 Boron methoxide (content of 97% or more) 330 ml (B ₂ O ₃ equivalent: 1.5)
Mol) and gallium isopropoxide (content of 96% or more) 20
g (Ga ₂ O ₃ conversion 0.040 mol), monoethanolamine 244g
(4 mol) and 180 g (3 mol) of acetic acid were dissolved or suspended in a 1: 1 mixed solvent of N-methylformamide and ethyl alcohol, and heated under reflux with stirring. The reaction was completed in 10 hours and the infrared absorption spectrum was measured.
A composition having a spectrum similar to that in the figure was obtained.

The concentration of this composition was adjusted to 15% by weight in terms of oxide with ethyl alcohol, and a performance test as an antioxidant was conducted in the same manner as in Example 1. The same result as in .7 was obtained.

Example 8 500 ml of the boron ethoxide in Example 1 was added to 250 ml (B ₂ O ₃
0.75 mol), 10 g of mono-secondary butoxyaluminum diisopropoxide (200 g (0.46 mol of Al ₂ O ₃ conversion), 450 g of monoethanolamine to 300 g (5 mol)) The operation was performed and the infrared absorption spectrum was measured after about 10 hours. As a result, a composition showing a spectrum substantially similar to that shown in FIG. 2 was obtained.

The concentration of this composition was adjusted with isopropyl alcohol so as to be 10% by weight in terms of oxide, and a performance test as an antioxidant was conducted in the same manner as in Example 1.
The same results as the sample No. 2 in Table 2 were obtained.

[Effects of the Invention] The present invention is configured as described above, and the effects thereof are summarized as follows.

(1) A completely new type of antioxidation using one or more metal alkoxides selected from the group consisting of B, Al, Ga and In and one or more metal alkoxides and amino alcohols and carboxylic acid as raw materials A metal-containing composition can be obtained.

(2) This metal-containing composition can be applied to a metal material and then heat-treated to form an oxide film to form a high-performance antioxidant film. In addition, it can be applied to a metal material to form a liquid continuous film. It has an excellent antioxidative effect even if it is formed, and the latter can be easily removed by washing with water after the end of operation, so metal materials that are susceptible to high temperature oxidation (especially steel and stainless steel) are treated at high temperature. At that time, it exerts an extremely excellent effect as an antioxidant.

[Brief description of drawings]

1 to 7 are infrared absorption spectra of the metal-containing compositions obtained in the examples.

Claims (5)

(57) [Claims] 1. A metal alkoxide selected from the group consisting of B, Al, Ga and In, one or more metal alkoxides, one or more amino alcohols, and a carboxylic acid in the presence of an organic solvent. A method for producing a water-soluble metal-containing composition for high-temperature oxidation prevention of a metal material, which comprises performing a heating reaction successively or simultaneously in the presence or absence of a solvent. 2. The method for producing a metal-containing composition according to claim 1, wherein the amino alcohol is ethanolamine represented by the following general formula. (B) R ₁ N (CH ₂ CH ₂ OH) ₂ (c) N (CH ₂ CH ₂ OH) ₃ [wherein R ₁ and R ₂ are C _n H _{2n + 1} (n is 0, ₁ to 4; Represents an integer) 3. A metal alkoxide has the general formula M (OR)
_3. A metal-containing composition according to claim 1 or 2, which is a metal alkoxide represented by the formula ₃ (wherein M represents B, Al, Ga or In, and R represents a lower alkyl group). Method. 4. The method for producing a metal-containing composition according to any one of claims 1 to 3, wherein the carboxylic acid is a lower aliphatic carboxylic acid. 5. Amino alcohols 0.05 to 4 moles and carboxylic acid 0.05 to 1 mole of metal element of metal alkoxide.
The method for producing a metal-containing composition according to any one of claims 1 to 4, wherein 4 to 4 mol are reacted by heating.