JPH0454760B2 - - Google Patents

Description

[Detailed description of the invention]

(a) Industrial application field The present invention is directed to an aluminum-based metal such as aluminum or an aluminum-containing alloy having an oxide film, and the surface of the oxide film has an opaque white to gray-white color with excellent color fastness and weather resistance. The present invention relates to a surface treatment agent for aluminum-based metals having an oxide film, which produces a substance. (b) Conventional technology In recent years, with changes in lifestyles and tastes, there has been a demand for coloring aluminum-based metal products used in building materials, nameplates, decorative items, daily necessities, vehicles, etc. In the fields of decorative goods, vehicles, building materials, etc., pastel-colored aluminum-based metal products are in high demand because they give a calm and warm feeling to the viewer. By the way, in order to color an aluminum-based metal product in a pastel tone, it is first necessary to color the aluminum-based metal semi-finished product in a basic opaque white to gray-white color. Conventionally, the following surface treatment method has been proposed as a method for coloring an aluminum-based metal semi-finished product in an opaque white to grayish white color. That is, (a) an aluminum-based metal semi-finished product having an anodized film is immersed in a solution containing sulfuric acid and at least one of calcium salt, magnesium salt, zinc salt, and aluminum salt, or electrolyzed in the solution; The treated anodic oxide film is immersed in a solution containing one or more substances that react with the products from the salts in the micropores to form a white to grayish-white compound, or electrolyzed in the solution. Publication No. 197897). (b) An aluminum or aluminum alloy material having an anodized film is immersed in an aqueous solution with a pH of 7 or more containing one or more alkaline earth metal ions to whiten it, and then the aluminum or aluminum A surface finishing (surface treatment) method has been proposed in which a post-treatment is performed to improve the whitening effect on the surface of an alloy material (Japanese Patent Application Laid-Open No. 53-92345). In this case, post-treatment to improve the whitening effect of the surface of aluminum or aluminum alloy material is to change the chemical structure by immersing it in an aqueous solution with a pH of 4 or less, or by immersing it in a weakly alkaline aqueous solution. By changing the physical and optical properties such as particle size, dissolving and roughening the oxide film, and thereby increasing the diffuse reflectance of the aluminum material surface and giving it a white color. It is intended to do so. (c) Problems to be Solved by the Invention However, the method (a) above involves coloring an aluminum-based metal semi-finished product having an anodic oxide film white to gray-white through the above steps, and therefore requires a large number of steps. In addition, two types of electrolytic
As a result of the necessity of a reaction apparatus, associated equipment, and water washing equipment, as well as personnel to manage them, the manufacturing cost becomes extremely high. Furthermore, this method also includes an electrolytic process, but in this case, it is difficult to control the electrolytic solution and electrolytic conditions, and the current density is concentrated at edges and convex parts, which can damage the aluminum-based metal semi-conductor that is the object to be processed. The current density at the center and concave portions of the product is reduced, resulting in insufficient reaction, resulting in uneven color and, in some cases, defective products. Furthermore, the above manufacturing method involves re-electrolysis, which causes a misalignment of the racking, and when this misalignment occurs, the electrode may come into contact with the insulating part (the part covered with Al ₂ O ₃ ), resulting in poor conduction. . The method (b) above, like the method (a) above, requires a large number of steps, and also requires two types of electrolysis/reaction devices, their accompanying equipment, and a water washing device. As a result of the need for personnel to manage the process, manufacturing costs become significantly higher. In addition, in this method, the diffuse reflectance increases and whitening progresses, but the wear resistance and durability of the oxide film decreases due to dissolution and roughening of the oxide film. When the oxide film is dissolved and roughened, the micropores in the oxide film expand, and in the subsequent pore sealing process, decolorization occurs, resulting in uneven color and a decrease in the whiteness of the oxide film, that is, thinning. This results in problems such as: Furthermore, in this method, the bonding force between the aluminum or aluminum alloy material and the alkaline earth metal compound is weak in the micropores of the oxide film in the aluminum or aluminum alloy material that has the oxide film, so that During a certain sealing process, the alkaline earth metal compound bleeds out, that is, decolorization occurs, and this sealing process causes further color unevenness, which poses problems such as a lack of practicality. (d) Means for Solving the Problems As a result of extensive research over many years in order to solve the above problems all at once, the inventors of the present invention decided to whiten the surface of an aluminum semi-finished metal product having an oxide film. For coloring to a grayish-white color, it is preferable to use a metal salt that produces a white to grayish-white hydrated metal oxide upon hydrolysis, and a surface treatment agent prepared by dissolving polyaminocarboxylic acids in an aqueous solution of the metal salt. The present inventors have discovered that a white to grayish-white film with uniform and excellent properties can be obtained by simply immersing the aluminum-based metal semi-finished product in the water, and have completed the present invention. That is, the first invention of the present application is a first invention that produces white to grayish-white hydrated metal oxides by hydrolysis.
This is a surface treatment agent for aluminum-based metals that has an oxide film and contains a metal salt and polyaminocarboxylic acids as essential components. Further, the second invention of the present application provides an oxide film containing as essential components a first metal salt, a polyaminocarboxylic acid, and a second metal salt that produce white to grayish-white hydrated metal oxides upon hydrolysis. It is a surface treatment agent for aluminum-based metals. Furthermore, the third invention of the present application provides a first method that produces white to grayish-white hydrated metal oxides by hydrolysis.
This is a surface treatment agent for aluminum-based metals having an oxide film, which contains metal salts of , polyaminocarboxylic acids, and fixing silicates as essential components. The present invention will be explained in detail below. First, the first invention of the present application will be explained in detail. That is, the first invention of the present application is a first invention that produces white to grayish-white hydrated metal oxides by hydrolysis.
This is a surface treatment agent for aluminum-based metals that has an oxide film and contains a metal salt and polyaminocarboxylic acids as essential components. The first compound used in the present invention that produces white to grayish-white hydrated metal oxides by hydrolysis.
The metal salt is particularly limited if it is a metal salt that is soluble or poorly soluble in water or a solution of water and polyaminocarboxylic acids described below, and that produces white to grayish-white hydrated metal oxides upon hydrolysis. It is not something that will be done. Specific representative examples of the first metal salt are:
At least one of zinc salts, calcium salts, barium salts, strontium salts, magnesium salts, aluminum salts, and the like can be mentioned. The concentration of the above metal salt is 0.01 to 200g/,
Particularly preferably, it is 0.1 to 100g/; if it is less than 0.01g/, the concentration may become too thin and a sufficiently dense film may not be obtained;
If it exceeds 200g/, the concentration becomes too high and when the liquid temperature drops (for example, in winter), metal salts will precipitate and the concentration will change, which may make it difficult to manage the surface treatment agent, which is not preferable. The surface treatment agent for aluminum-based metals having an oxide film of the present invention contains the above-mentioned first metal salt and polyaminocarboxylic acids as essential components. In addition, the polyaminocarboxylic acids used in the present invention are determined by the stability of metal ions in the surface treatment agent, and by the stability of the metal ions generated on the surface (oxide film) when the aluminum metal is immersed in the surface treatment agent. In addition to stabilizing the sol of hydrated metal oxides, in particular, the hydrated metal oxides are bonded extremely easily, uniformly, and firmly to the oxide film part of an aluminum-based metal having an oxide film. It is. In this way, when polyaminocarboxylic acids are used, the product from the metal salt is fixed in the oxide film of an aluminum-based metal having an oxide film due to the -COO ^- bonded to one nitrogen atom. -COO ^- , which is bonded to the product from the first metal salt and also bonded to the other nitrogen atom, is electrostatically coordinated within the micropores of the aluminum-based metal oxide film ^. It is understood that this is because the products from the metal salt are fixed in the micropores of the oxide film. Also, hydrolysates from metal salts (colloidal substances)
is negatively charged, and is electrically attracted around Al ³⁺ and other metal ions (alkali metal ions and metal ions from the first metal salt) in the micropores in the oxide film. As a result, the product from the first metal salt concentrates in the micropores, and as a result, even the aluminum-based metal with a complicated formation can be uniformly colored. Furthermore, since the product generated from the first metal salt is electrostatically fixed within the micropores, it is difficult to desorb, that is, decolorize, during pore sealing, and it is understood that this is because the product can be uniformly colored. It is. In fact, by using polyaminocarboxylic acids, pastel colored films with excellent properties can be obtained. In the present invention, hydrated metal oxides include those in which one or more water molecules are coordinated to the oxide of a metal salt corresponding to the first metal salt, hydrated metal oxides, or metal hydroxides. Refers to things or collections of these things. Specific representative examples of the above polyaminocarboxylic acids include ethylenediaminetetraacetic acid and its alkali metal salts such as its sodium salt, trans-1,2-
Cyclohexanediaminetetraacetic acid, diethylenetriaminepentaacetic acid, ethylenediaminediacetic acid, 3,6-
Dioxa-1,8-octanediaminetetraacetic acid, N
-(2-Hydroxyethyl)ethylenediaminetriacetic acid, N-(2-hydroxyethyl)iminodiacetic acid, triethylenetetraminehexaacetic acid, or their alkali metal salts, among others, are particularly inexpensive and easy to handle. Preferably, ethylenediaminetetraacetic acid and/or its alkali metal salts are conveniently used. These include polyaminocarboxylic acids that are insoluble in water, but by dispersing them in water or adding an organic polar solvent, in other words, they can be dissolved in a mixture of water and an organic polar solvent. be. The concentration of the above polyaminocarboxylic acids is as follows:
Although it varies depending on the type and concentration of the first metal salt used, it is generally preferably in the range of 0.1 to 50 g/,
If it is less than 0.1g/, the effect will be poor;
If it exceeds g/, there will be a limit to the effect and the first
This is undesirable because it may affect the solubility of the metal salt. Incidentally, in the present invention, an organic polar solvent may be used, but the organic polar solvent is not particularly limited as long as it is a water-soluble polar solvent, and specifically, for example, methanol, ethanol, etc. Examples include lower alcohols such as, ketones such as acetone, methyl ethyl ketone, and diethyl ketone, and ethers such as ether and diethyl ether. The concentration of the organic polar solvent is preferably 0.1 to 50% by volume. That is, because the surface treatment agent of the present invention contains the above-mentioned polyaminocarboxylic acids, an aluminum-based metal having an oxide film can be coated with an excellent white to grayish white color on its surface by simply immersing it. Although it is possible to form a dense film, it is also possible to improve the solubility of polyaminocarboxylic acids and to stabilize the product from the first metal salt by including an organic polar solvent therein. Therefore, it is preferable. If the concentration of the organic polar solvent is less than 0.1% by volume, it may become too dilute and a sufficient effect may not be obtained.On the other hand, if it exceeds 50% by volume, the concentration becomes too high and dissolves the first metal salt. It is not desirable because it affects sexuality. The surface treatment agent for aluminum-based metals having an oxide film of the present invention (hereinafter referred to as surface treatment agent) contains the above-mentioned first metal salt and polyaminocarboxylic acids as essential components, and water and optionally a PH adjuster. is added to the solution. The pH of this surface treatment agent is in the range of 0.5 to 3.
In particular, it is preferable to keep it in the range of 1.5 to 3, and the pH is 0.5.
If the pH is less than 3, the acidity may become too high and the film may be destroyed. Conversely, if the pH exceeds 3, the first metal salt may be hydrolyzed and the surface treatment agent may be damaged during storage or handling. It becomes cloudy, and when aluminum-based metal with an oxide film is immersed,
There is a risk that particles of white to grayish-white hydrated metal oxides generated by hydrolysis may become too large to penetrate into the surface area (oxide film part) of the aluminum metal, or it may become impossible to obtain a dense film. I don't like it because there is. In the above pH range, it is understood that a few molecules of hydrated metal oxides aggregate to form a colorless and transparent to slightly cloudy hydrosol. The above pH adjusters include inorganic acids such as sulfuric acid and phosphoric acid, acetic acid, citric acid, succinic acid, gluconic acid,
Examples include organic acids such as glycine, malonic acid, oxalic acid, and formic acid, alkali metal hydroxides, carbonates or bicarbonates, ammonia, and alkali metal salts of organic acids. One type of these acids or bases or alkali metal salts of organic acids may be used, or two or more types may be used in combination, and the combination thereof may be particularly effective in some cases. Next, the second invention of the present application will be explained. The second invention of the present application is an improvement of the first invention. That is, a surface treatment agent for aluminum-based metals having an oxide film, which contains as essential components a first metal salt, a polyaminocarboxylic acid, and a second metal salt that produce white to grayish-white hydrated metal oxides upon hydrolysis. It is. In the present invention, in the first invention, a second metal salt is added to the first metal salt that produces white to grayish-white hydrated metal oxides by hydrolysis, and other requirements, such as The type and concentration of the first metal salt and polyaminocarboxylic acids, the PH range of the surface treatment agent, the PH adjuster, etc. are the same as in the first invention. The second metal salt used in the present invention is a metal salt other than the first metal salt, and is a metal salt containing hydrated metal oxides on the surface part (oxide film part) of an aluminum-based metal having an oxide film. When forming a film, it is used to further improve the density of the film, or to color the film arbitrarily in the range of white to grayish white. Specific representative examples of the second metal salt are:
Examples include various metal salts such as iron, nickel, cobalt, manganese, chromium, cadmium, tin, copper, lead, indium, tungsten, silver, molybdenum, or vanadium. These metal salts may be used alone or in combination of two or more. In addition, the concentration of the second metal salt varies depending on the type and combination of metal salts used, but
Usually 0.01-100g/, preferably 0.1-50g/
It is desirable that the range be within the range of . Next, the third invention of the present application will be explained. The third invention of the present application is an improvement of the first invention. That is, it is a surface treatment agent for aluminum-based metals having an oxide film, which contains as essential components a first metal salt, polyaminocarboxylic acids, and a fixing silicate that produce white to grayish-white hydrated metal oxides upon hydrolysis. be. The present invention is the first invention, in which a fixing silicate is added, and other requirements, such as the type and concentration of the first metal salt and polyaminocarboxylic acids, as well as the PH range and PH of the surface treatment agent, are provided. The adjusting agent and the like are the same as in the first invention. The fixing silicate used in the present invention forms a uniform film of an opaque white to grayish-white hydrated metal oxide on the surface of the aluminum metal having an oxide film (oxide film part) to seal the pores. When this is done, the hydrated metal oxides are fixed on the surface area to prevent their desorption, thereby preventing decolorization. The fixing silicate is not particularly limited as long as it can be dissolved or dispersed in the form of fine particles in water or an aqueous solution of polyaminocarboxylic acids, and typical examples include sodium silicate, potassium silicate, or potassium silicate. Soluble alkali silicates such as lithium silicate, aluminum silicate, potassium aluminum silicate, sodium aluminum silicate,
Examples include fine particulate aqueous dispersions of calcium aluminum silicate. The concentration of the above-mentioned fixing silicate varies depending on the type and concentration of the polyaminocarboxylate used, the type of silicate, etc., but is usually 0.1 to 100 g/
, preferably in the range of 0.5 to 50 g/. In the present invention, an aluminum-based metal having an oxide film refers to an aluminum-based metal in which an oxide film is formed on the surface of aluminum or an alloy containing aluminum by chemical or electrochemical (anodic oxidation). It is preferable that a white to grayish-white oxide film with better characteristics can be obtained. A known anodic oxidation method is employed to form an anodic oxide film on the aluminum-based metal. Specifically, for example, inorganic acids such as sulfuric acid, phosphoric acid, and chromic acid; organic acids such as oxalic acid, paraphenolsulfonic acid, sulfosalicylic acid, and malonic acid; or sodium hydroxide, trisodium phosphate, etc. An anodic oxide film is formed in an aqueous solution by electrolysis using direct current, alternating current, pulse, PR waves, or AC/DC superposition method. Next, examples of use of the surface treatment agent of the present invention will be described below. When coloring the surface of an aluminum-based metal having an oxide film white to grayish white, the above surface treatment agent is placed in a treatment tank, and if desired, the concentration is adjusted with water and/or an organic polar solvent or a chelate compound, and the pH is adjusted. Adjust the pH with a treatment agent, and adjust the temperature of the treatment solution to usually room temperature to 75°C, preferably 40 to 70°C.
By immersing the aluminum-based metal in this solution for usually 10 seconds to 20 minutes, preferably 1 minute to 15 minutes, a dense white to gray-white film with excellent properties can be obtained in a single treatment. be. In addition, the surface treatment agent of the present invention can produce a uniform and dense white to grayish-white film simply by immersing aluminum-based metals, so even when electrolyzed, a film with excellent properties can be obtained without strict conditions. can be obtained. (e) Effect The present invention has the above configuration, and when polyaminocarboxylic acids are used in the surface treatment agent, white to grayish-white hydrated metal oxides are produced by the polyaminocarboxylic acids due to metal ions or changes in pH. It not only stabilizes the sols of the above types, but also has the effect of extremely easily, uniformly and strongly bonding the hydrated metal oxides to the oxide film part of the aluminum-based metal having an oxide film. be. In this way, when polyaminocarboxylic acids are used, the product from the metal salt is fixed in the oxide film of an aluminum-based metal having an oxide film due to the -COO ^- bonded to one nitrogen atom. -COO ^- , which is bonded to the product from the first metal salt and also bonded to the other nitrogen atom, is electrostatically coordinated within the micropores of the aluminum-based metal oxide film ^. It is understood that this is because the product from the first metal salt is fixed in the micropores of the oxide film. Also, hydrolysates from metal salts (colloidal substances)
is negatively charged and is electrically attracted around Al ³⁺ and other metal ions (alkali metal ions and metal ions from metal salts) in the micropores of the oxide film. Products from the metal salt concentrate in the micropores, and as a result, even complexly formed aluminum metals can be uniformly colored. Furthermore, since the product produced from the metal salt is electrostatically fixed within the micropores, it is difficult to desorb, that is, decolorize, during sealing, and has the effect of uniformly coloring the pores. In particular, since the surface treatment agent of the present invention can chemically form a white to grayish-white, uniform and dense film just by immersion, it is easy to form a film with excellent properties even by electrolysis. Therefore, there is no need for expensive electrolysis equipment or accompanying control equipment, and moreover, electrolysis can be used without strictly controlling the electrolyte, electrolysis conditions, current density distribution, etc.
It has the ability to form a uniform film even on aluminum-based metals that have complex oxide films. In this case, if an organic polar solvent is included in the surface treatment agent, the solubility of the polyaminocarboxylic acids will be improved, the degree of freedom of the white to gray-white hydrated metal oxide hydrosol will be reduced, and the oxide film will be reduced. The above-mentioned hydrated metal oxides are precipitated on the oxide film due to the change in pH caused by immersing the aluminum-based metal. In addition, when an organic polar solvent is added to the surface treatment agent, the organic polar solvent removes the water molecules coordinated to the colloidal particles in the white to off-white hydrosol of hydrated metal oxides and the oxide film. It also has the effect of continuously producing a fine hydrosol of hydrated metal oxides on the surface of the aluminum-based metal by removing water molecules coordinating with the metal. (f) Examples Hereinafter, the present invention will be explained in detail based on Examples, but the present invention is not limited thereto. Examples 1 to 6 The composition of each surface treatment agent of Examples 1 to 6 was
Shown in the table. Comparative Examples 1 to 6 Examples 1 to 6 above except for the polyaminocarboxylic acids as the respective components were used. Examples 7 to 9 The composition of each surface treatment agent of Examples 7 to 9 was
Shown in the table.

【table】

[Table] Examples 10 to 20 The composition of each surface treatment agent in Examples 10 to 20 was
Shown in the table.

[Table] Examples 21 to 23 Table 4 shows the compositions of the surface treatment agents of Examples 21 to 23.

[Table] Using each of the above Examples and Comparative Examples, a white to grayish-white coloring test was conducted under the conditions shown in Table 5. The anodic oxide film used in each of the above Examples and Comparative Examples, as well as the Reference Examples described below, was prepared by pre-treating a pure aluminum plate with normal degreasing, etc., using a sulfuric acid concentration of 180 g/, a bath temperature of 20°C, and an electric current. Density 1.5A/d
It was obtained by direct current electrolysis for 18 minutes under conditions of m ² . In this case, the thickness of the anodic oxide film was 8 μm. The results are shown in Table 5 and Reference Examples.

【table】

[Table] Reference example Pure aluminum plate with the above anodic oxide film formed with calcium acetate 30g/and sulfuric acid 0.5g/
in an aqueous solution at a temperature of 30℃ and an AC voltage of 20V.
Electrolysis was carried out for 10 minutes, and after washing with water, electrolysis was carried out in an aqueous solution containing 30 g of phosphoric acid at a temperature of 30°C for 10 minutes at an AC voltage of 20 V to obtain a white film on the surface of the aluminum plate. Comparative Example 1 A pure aluminum plate with an anodized film was soaked in an aqueous solution (temperature 60°C) containing 50 g of aluminum sulfate for 20 minutes.
The plate was immersed for a minute, and then washed with water, and then immersed in an aqueous solution containing 50 g of aluminum sulfate/10 g of citric acid to form a white film on the surface of the pure aluminum plate. This white film was pale and uneven in color, and was not suitable for practical use. Comparative Example 2 A pure aluminum plate with an anodized film was immersed in an aqueous solution (temperature 60°C) containing 50 g of aluminum sulfate for 20 minutes.
The plate was immersed for a minute, and then washed with water, and then immersed in an aqueous solution containing 50 g of aluminum sulfate and 10 g of tartaric acid to form a white film on the surface of the pure aluminum plate. This white film was pale and uneven in color, and was not suitable for practical use. Comparative Example 3 A pure aluminum plate with an anodized film was immersed in an aqueous solution (temperature 60°C) containing 50 g of aluminum sulfate for 20 minutes.
The plate was immersed for a minute, and then washed with water, and then immersed in an aqueous solution containing 50 g of aluminum sulfate and 10 g of citric acid to form a white film on the surface of the pure aluminum plate. This white film was pale and uneven in color, and was not suitable for practical use. As shown in the color tone results in Table 5, a surface treatment agent containing a metal salt and a polyaminocarboxylic acid as essential components that produce white to grayish-white hydrated metal oxides upon hydrolysis, that is, the first invention of the present application. The anodic oxide film could be colored white by the surface treatment agent, and almost no color unevenness was observed. In addition, the second invention of the present application is the one in which a second metal salt is added to the first invention, and this makes it possible to uniformly color (from white to grayish white), and also to significantly shorten the coloring time. It has been found that by selecting the metal salt No. 2, it is possible to color the product in a color ranging from white to grayish-white depending on the intended use. Furthermore, according to the third invention of the present application, it has been found that decolorization is reliably prevented when an aluminum-based metal having an anodized film is colored white to grayish white and then sealed. When the white to grayish-white films of each of the above examples were colored and sealed using dyes or metal salts by known screen printing methods, thermal transfer methods, dipping methods, etc., uniform and dense pastel-like films were obtained. Ta. In contrast, the comparative examples have large color unevenness and lack practicality, and the reference examples have uneven color between the edges and the center, and both have good weather resistance. No results were obtained. (g) Effects of the Invention The surface treatment agent of the present invention can uniformly color an aluminum-based metal having an oxide film to a white or grayish color by simply immersing it, and the reaction rate is faster than when electrolytically applied. It is possible to form a white to grayish-white film that is uniform, dense, and has excellent weather resistance without any variation in color. In addition, the surface treatment agent of the present invention chemically colors the above-mentioned oxide film to an opaque white or grayish white color, and compared to coloring by electrolysis, equipment costs and running costs are significantly lower, and the reaction conditions and In addition to being easy to manage the surface treatment agent, it also has the effect of uniformly coloring even complex-shaped objects without the use of special equipment. Furthermore, when a fixing silicate is added to the surface treatment agent of the present invention, the fixing silicate causes white to grayish-white hydrated metal oxides to form on the surface of the aluminum metal (oxidized This has the effect of fixing on the film and further preventing its desorption, that is, decolorization, thereby producing a pastel-colored film with even better characteristics.

Claims (1)

[Scope of Claims] 1. A surface treatment agent for aluminum-based metals having an oxide film, which contains as essential components a first metal salt that produces white to off-white hydrated metal oxides upon hydrolysis and polyaminocarboxylic acids. 2. The surface of an aluminum-based metal having an oxide film according to claim 1, wherein the first metal salt is at least one of zinc salt, calcium salt, barium salt, strontium salt, magnesium salt, or aluminum salt. Processing agent. 3. The surface treatment agent for aluminum-based metals having an oxide film according to claim 1 or 2, wherein the first metal salt has a concentration of 0.01 to 200 g/2. 4 Concentration of polyaminocarboxylic acids is 0.1 to 50
The surface treatment agent for aluminum-based metals having an oxide film according to any one of claims 1 to 3, wherein the surface treatment agent has an oxide film of: 5. The essential components are a first metal salt, a polyaminocarboxylic acid, and a second metal salt that produce white to grayish-white hydrated metal oxides upon hydrolysis.
A surface treatment agent for aluminum-based metals that has an oxide film. 6. Aluminum-based material having an oxide film according to claim 5, wherein the first metal salt is at least one of zinc acid, calcium salt, barium salt, strontium salt, indium salt, magnesium salt, or aluminum salt. Metal surface treatment agent. 7. The surface treatment agent for aluminum-based metals having an oxide film according to claim 5 or 6, wherein the first metal salt has a concentration of 0.01 to 200 g/. 8. Claims 5 to 8, wherein the second metal salt is at least one of iron salt, nickel salt, cobalt salt, manganese salt, chromium salt, cadmium salt, tin salt, lead salt, indium salt, or vanadium salt. 7th
A surface treatment agent for aluminum-based metals having an oxide film according to any one of Items 1 to 3. 9. The surface treatment agent for aluminum-based metals having an oxide film according to any one of claims 5 to 8, wherein the second metal salt has a concentration of 0.01 to 100 g/. 10 Concentration of polyaminocarboxylic acids is 0.1-50
The surface treatment agent for aluminum-based metals having an oxide film according to any one of claims 5 to 9, which has an oxidation film of 100 g/g/. 11. A surface treatment agent for aluminum-based metals having an oxide film, which contains as essential components a first metal salt that produces white to off-white hydrated metal oxides upon hydrolysis, polyaminocarboxylic acids, and a fixing silicate. 12. The aluminum base having an oxide film according to claim 11, wherein the first metal salt is at least one of zinc salt, calcium salt, barium salt, strontium salt, indium salt, magnesium salt, or aluminum salt. Metal surface treatment agent. 13. The surface treatment agent for aluminum-based metals having an oxide film according to claim 11 or 12, wherein the first metal salt has a concentration of 0.01 to 200 g/. 14 Concentration of polyaminocarboxylic acids is 0.1 to 50
Claims 11 to 13 which are g/
A surface treatment agent for aluminum-based metals having an oxide film according to any one of Items 1 to 3. 15. The surface treatment agent for aluminum metal having an oxide film according to any one of claims 11 to 14, wherein the fixing silicate is an alkali silicate. 16. The surface treatment agent for aluminum-based metals having an oxide film according to any one of claims 11 to 15, wherein the concentration of the fixing silicate is 0.1 to 100 g/.