Etching solution

Abstract

To provide a technique that improves water repellency of aluminum material.SOLUTION: An etching process liquid for improving the water repellency of aluminum material contains alkali and zinc ion sources.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to an etching treatment liquid or the like for improving the water repellency of aluminum materials.

Background Art

[0002] Aluminum materials are used in a wide range of fields such as transportation equipment, building materials, industrial equipment, containers, and daily necessities. When exposed to the external environment, problems such as contamination and mold growth occur due to water adhering to the aluminum material. As a measure to solve this problem, it has been proposed to improve the water repellency of the aluminum material to suppress the adhesion of water or to make it possible to easily remove the water even if it adheres.

[0003] In Patent Document 1, a technique has been proposed to exhibit high water repellency by imparting appropriate roughness to the surface of an aluminum material, forming a first film containing an Fe compound, and further forming a second film having water repellency. However, this technique includes a plurality of film forming steps in addition to the step of imparting roughness, and lacks simplicity.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] An object of the present invention is to provide a technique for improving the water repellency of aluminum materials.

Means for Solving the Problems

[0006] In view of the above problems, the inventors diligently conducted research and found that water repellency can be improved by etching aluminum material with a treatment solution containing alkali and zinc ion sources. Based on this finding, the inventors furthered their research and completed the present invention. That is, the present invention encompasses the following aspects.

[0007] Item 1. An etching solution containing an alkali and zinc ion source for improving the water repellency of aluminum materials.

[0008] Item 2. The etching solution according to Item 1, wherein the alkali is an alkali metal hydroxide.

[0009] Item 3. The etching solution according to item 1 or 2, further containing a metal salt.

[0010] Item 4. The etching solution according to Item 3, wherein the metal salt is at least one selected from the group consisting of iron salts, copper salts, nickel salts, and silver salts.

[0011] Item 5. An etching solution according to any one of items 1 to 4, further containing an amine compound.

[0012] Item 6. The etching solution according to Item 5, wherein the amine compound is at least one selected from the group consisting of dimethylamine-epichlorohydrin copolymer, monoethanolamine, ethylenediamine, and polyethyleneimine.

[0013] Item 7. An etching solution according to any one of items 1 to 6, further containing a stabilizer.

[0014] Item 8. The etching solution according to Item 7, wherein the stabilizer is at least one selected from the group consisting of carboxylic acids and salts thereof.

[0015] Item 9. The etching treatment liquid according to Item 7 or 8, wherein the stabilizer is at least one selected from the group consisting of hydroxycarboxylic acids, aromatic carboxylic acids, and salts thereof.

[0016] Item 10. The etching treatment liquid according to any one of Items 7 to 9, wherein the stabilizer is at least one selected from gluconic acid, tartaric acid, malic acid, citric acid, salicylic acid, salicylic acid derivatives, phthalic acid, γ-resorcylic acid, and salts thereof.

[0017] Item 11. The etching treatment liquid according to any one of Items 1 to 10 for use in alkaline etching in an aluminum material treatment method for performing alkaline etching and smut removal treatment.

[0018] Item 12. An etching treatment liquid for an aluminum material, containing an alkali, a zinc ion source, a metal salt, and an amine compound.

[0019] Item 13. (Step 1) A step of treating an aluminum material with the etching treatment liquid according to any one of Items 1 to 12 A method for improving the water repellency of an aluminum material, including this.

[0020] Item 14. Further, (Step 2) A step of performing a smut removal treatment on the aluminum material after the Step 1 The method according to Item 13, including this.

[0021] Item 15. The method according to Item 14, in which the cycles of the Step 1 and the Step 2 are performed a plurality of times.

[0022] Item 16. Further, (Step 3) A step of anodizing the aluminum material after the Step 2 or after the end of the cycle The method according to Item 14 or 15, including this.

[0023] Item 17. Further, (Step 4) A step of performing a sealing treatment on the aluminum material after the Step 3 The method according to claim 16, comprising

[0024] Claim 18. Further, (Step 5) A step of performing rust prevention treatment on the aluminum material after the step 2, after the cycle ends, after the step 3, or after the step 4 The method according to any one of claims 14 to 17, comprising

[0025] Claim 19. (Step 1) A step of treating an aluminum material with an etching treatment liquid according to any one of claims 1 to 12 A method for producing a water-repellent aluminum material, comprising

[0026] Claim 20. A water-repellent aluminum material obtained by the method according to claim 19

Effect of the Invention

[0027] According to the present invention, there can be provided an etching treatment liquid for improving the water repellency of an aluminum material, a method for improving the water repellency of an aluminum material, a method for producing a water-repellent aluminum material, a water-repellent aluminum material, and the like.

Mode for Carrying Out the Invention

[0028] In the present specification, expressions such as "containing" and "comprising" include concepts such as "containing", "comprising", "substantially consisting of", and "consisting only of".

[0029] In one aspect of the present invention, there is provided an etching treatment liquid for improving the water repellency of an aluminum material (which may also be referred to as "the etching treatment liquid of the present invention" in the present specification) containing an alkali and a zinc ion source, and a technique for improving the water repellency of an aluminum material using the same. Hereinafter, these will be described.

[0030] The alkali is not particularly limited, but examples include hydroxides and carbonates of alkali metals such as sodium, potassium, and lithium (e.g., sodium hydroxide, potassium hydroxide, lithium hydroxide, sodium carbonate, potassium carbonate, etc.); and hydroxides of alkaline earth metals such as magnesium, calcium, and strontium (e.g., magnesium hydroxide, calcium hydroxide, strontium hydroxide, etc.). Among these, alkali metal hydroxides are preferred, more preferably sodium hydroxide and potassium hydroxide, and even more preferably sodium hydroxide.

[0031] The alkali may be a single type or a combination of two or more types.

[0032] The alkali concentration in the etching solution of the present invention is not particularly limited, as long as it is at a concentration sufficient to etch aluminum material. The concentration is, for example, 20 to 1000 g / L, preferably 100 to 700 g / L, and more preferably 150 to 450 g / L.

[0033] The zinc ion source is not particularly limited, and any source capable of ionizing zinc ions in water can be widely used. Examples of zinc ion sources include zinc oxide, zinc acetate, zinc nitrate, zinc borate, zinc chloride, zinc ammonium chloride, zinc fluorosilica, zinc cyanide, zinc sulfate, zinc bromide, basic zinc carbonate, and zinc sulfide. Among these, zinc oxide, zinc acetate, zinc nitrate, and zinc sulfate are preferred, and zinc oxide is more preferred.

[0034] The zinc ion source may be a single type or a combination of two or more types.

[0035] The concentration of the zinc ion source in the etching solution of the present invention is not particularly limited. The concentration is, for example, 1 to 500 g / L, preferably 5 to 300 g / L, more preferably 10 to 200 g / L, and even more preferably 20 to 100 g / L. Alternatively, the concentration is, for example, 0.01 to 6.2 mol / L, preferably 0.06 to 3.7 mol / L, more preferably 0.12 to 2.5 mol / L, and even more preferably 0.24 to 1.3 mol / L.

[0036] From the viewpoint of water repellency, the etching solution of the present invention preferably further contains a metal salt.

[0037] The metal salt is not particularly limited, but examples include salts of transition metals other than zinc, such as iron, copper, nickel, silver, cobalt, manganese, and tin. Among these, salts of iron, copper, nickel, and silver are preferred. The type of salt is not particularly limited, and examples include salts with strong acids such as nitrates, sulfates, and hydrochlorides; and salts with weak acids such as acetates. Among these, salts with strong acids are preferred, and nitrates and sulfates are more preferred. Specific examples of metal salts that are preferred include iron(II) sulfate, iron(III) sulfate, iron(II) nitrate, iron(III) nitrate, nickel sulfate, nickel nitrate, copper sulfate, copper nitrate, silver sulfate, and silver nitrate.

[0038] The metal salt may be a single type or a combination of two or more types.

[0039] When the etching solution of the present invention contains a metal salt, its concentration is not particularly limited. The concentration is, for example, 0.1 to 100 g / L, preferably 0.5 to 50 g / L, and more preferably 1 to 20 g / L. Alternatively, the concentration is, for example, 0.0002 to 0.25 mol / L, preferably 0.0012 to 0.13 mol / L, and more preferably 0.002 to 0.05 mol / L.

[0040] From the viewpoint of water repellency, the etching solution of the present invention preferably further contains an amine compound.

[0041] The amine compound is not particularly limited, but examples include aliphatic amines, aromatic amines, heterocyclic amines, amine derivatives, and polymers using these as constituent units.

[0042] Examples of aliphatic amines include methylamine, dimethylamine, trimethylamine, ethylamine, diethylamine, triethylamine, ethylenediamine, monoethanolamine, diethanolamine, triethanolamine, polyethyleneimine, N,N-diisopropylethylamine, tetramethylethylenediamine, hexamethylenediamine, spermidine, spermine, and amantadine.

[0043] Examples of aromatic amines include aniline, phenethylamine, toluidine, catecholamine, and 1,8-bis(dimethylamino)naphthalene (proton sponge).

[0044] Examples of heterocyclic amines include pyrrolidine, piperidine, piperazine, morpholine, quinuclidine, 1,4-diazabicyclo[2.2.2]octane, pyrrole, pyrazole, imidazole, pyridine, pyridazine, pyrimidine, pyrazine, oxazole, thiazole, and 4-dimethylaminopyridine.

[0045] Examples of amine derivatives include etheramines and amino acids.

[0046] The polymers using the above-mentioned amine compounds as constituent units are not particularly limited, as long as they are polymers of the above-mentioned amine compounds with each other or with other constituent units. Preferred polymers include copolymers of aliphatic amines (preferably (mono, di, or tri)alkylamines, more preferably dialkylamines, and even more preferably dimethylamines) and other reactive monomers (for example, monomers having reactive groups such as epoxy groups or alkyl halogenated groups, preferably epichlorohydrins). A preferred example of such copolymer is a dimethylamine-epichlorohydrin copolymer.

[0047] Examples of amine compounds include aliphatic amines and polymers with aliphatic amines as constituent units, and particularly preferred examples include dimethylamine-epichlorohydrin copolymer, monoethanolamine, ethylenediamine, and polyethyleneimine.

[0048] The amine compound may be a single compound or a combination of two or more compounds. In one embodiment of the present invention, from the viewpoint of suppressing differences in the degree of etching depending on the location on the aluminum material surface, the amine compound is preferably a polymer consisting of an amine compound (particularly an aliphatic amine) as a constituent unit, or a combination of the polymer and other amine compounds (particularly aliphatic amines). In particular, a combination of dimethylamine-epichlorohydrin copolymer and at least one selected from the group consisting of monoethanolamine, ethylenediamine, and polyethyleneimine is preferred.

[0049] If the etching solution of the present invention contains an amine compound, its concentration is not particularly limited. The concentration is, for example, 1 mg to 10 g / L, preferably 10 to 1000 mg / L, and more preferably 20 to 200 mg / L.

[0050] From the viewpoint of water repellency and bath stability (especially bath stability when further containing metal salts), it is preferable that the etching solution of the present invention further contains a stabilizer.

[0051] The stabilizer is not particularly limited as long as it forms a complex with the metal salt. Specific examples of stabilizers include carboxylic acids and their salts.

[0052] Preferred carboxylic acids include hydroxycarboxylic acids and aromatic carboxylic acids.

[0053] The hydroxycarboxylic acid is not particularly limited as long as it has an aliphatic skeleton, and examples include gluconic acid, citric acid, lactic acid, glycolic acid, malic acid, tartaric acid, glucuronic acid, glucaric acid, lactobionic acid, N-acetylneuraminic acid, N-glycolylneuraminic acid, O-acetylneuraminic acid, and deaminoneuraminic acid. Among these, gluconic acid, tartaric acid, malic acid, and citric acid are preferred.

[0054] Aromatic carboxylic acids are not particularly limited as long as they have an aromatic skeleton, and examples include salicylic acid, salicylic acid derivatives (for example, derivatives in which an alkyl group is substituted on a benzene skeleton), phthalic acid, γ-resorcylic acid, benzoic acid, mandelic acid, 3-hydroxybenzoic acid, 4-hydroxybenzoic acid, gallic acid, cinnamic acid, etc. The aromatic carboxylic acid preferably has the general formula (1):

[0055] [ka]

[0056] [In the formula: R 1 R represents a hydroxyl group or a carboxyl group. 2 This indicates a hydroxyl group or an alkyl group. It is a compound represented by [formula].

[0057] R 2 The alkyl group represented by includes both linear and branched groups. The number of carbon atoms in the alkyl group is not particularly limited, for example, 1 to 6. Preferably, the number of carbon atoms is 1 to 4, more preferably 1 to 2, and even more preferably 1. Specific examples of the alkyl group include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, tert-butyl group, sec-butyl group, and the like.

[0058] Preferred examples of compounds represented by general formula (1) include salicylic acid, 3-methylsalicylic acid, phthalic acid, and γ-resorcylic acid.

[0059] In addition to the above, other carboxylic acids such as acetic acid, oxalic acid, malonic acid, pyrophosphate, triphosphate, and condensed phosphoric acid can also be used as carboxylic acids.

[0060] The stabilizer may be a single type or a combination of two or more types.

[0061] If the etching solution of the present invention contains a stabilizer, its concentration is not particularly limited. The concentration is, for example, 1 to 200 g / L, preferably 2.5 to 100 g / L, and more preferably 5 to 50 g / L.

[0062] The etching solution of the present invention may contain other components besides those mentioned above, as long as they do not significantly impair the effects of the present invention. Examples of other components include thickeners and dyes.

[0063] The content of other components is, for example, 0 to 5% by mass, preferably 0 to 3% by mass, more preferably 0 to 1% by mass, even more preferably 0 to 0.5% by mass, and even more preferably 0% by mass, based on 100% by mass of the etching solution of the present invention.

[0064] The pH of the etching solution of the present invention is alkaline, for example, 10 or higher, preferably 11 or higher, more preferably 12 or higher, and even more preferably 13 or higher.

[0065] The etching solution of the present invention can be manufactured by appropriately mixing each component using water as the solvent. In addition to water, other solvents may be added to water, as long as they do not significantly impair the effects of the present invention.

[0066] Etching solutions containing alkali, a zinc ion source, a metal salt, and an amine compound (preferably further containing a stabilizer) are particularly excellent for improving the water repellency of aluminum materials. In one aspect, the present invention relates to an etching solution for aluminum materials containing alkali, a zinc ion source, a metal salt, and an amine compound (preferably further containing a stabilizer).

[0067] The etching solution of the present invention can be used to improve the water repellency of aluminum materials. Preferably, the etching solution of the present invention can be used for alkaline etching in an aluminum material processing method that performs alkaline etching and smut removal. The alkaline etching process is performed according to step 1 described below, and the smut removal process is performed according to step 2 described below. Also preferably, the etching solution of the present invention can be used in the method of the present invention described below.

[0068] According to a preferred embodiment of the present invention, it is possible to obtain an aluminum material that is highly water-repellent, and even super-water-repellent. Specifically, according to a preferred embodiment of the present invention, it is possible to obtain an aluminum material with a surface contact angle of, for example, 120° or more, 125° or more, 130° or more, 135° or more, 140° or more, 145° or more, 150° or more, or 155° or more.

[0069] The contact angle of an aluminum surface can be measured as follows: The contact angle of a test specimen was measured using the "Kyowa Interface Science Co., Ltd.: Automatic Contact Angle Meter DM-301" or an equivalent product. The "32G needle" was used, and the contact angle could be measured when 1 μl of water was dropped onto the test specimen.

[0070] The aluminum material is not particularly limited as long as the surface portion to be treated is formed of aluminum or an aluminum alloy. For example, in addition to various articles made of aluminum or aluminum alloy, articles with aluminum plating or aluminum alloy plating film formed on various base materials such as steel plates, articles that have undergone hot-dip aluminum plating, castings, die-casts, etc., can be used. The aluminum alloy is not particularly limited, and various alloys in which aluminum is the main metal component can be used. For example, A1000 series semi-aluminum alloys, A2000 series aluminum alloys containing copper and manganese, A3000 series aluminum-manganese alloys, A4000 series aluminum-silicon alloys, A5000 series aluminum-magnesium alloys, A6000 series aluminum-magnesium-silicon alloys, A7000 series aluminum-zinc-magnesium alloys, A8000 series aluminum-lithium alloys, etc., can be applied. The surface of the aluminum material may be pre-treated, such as degreasing. The aluminum material targeted by the present invention is preferably an aluminum material whose surface has been degreased.

[0071] A method (the method of the present invention) that includes a step of treating an aluminum material with the etching solution of the present invention (step 1) makes it possible to improve the water repellency of an aluminum material and to produce an aluminum material with improved water repellency.

[0072] The manner of processing in Step 1 is not particularly limited as long as the etching solution of the present invention can come into contact with the surface of the aluminum material. For example, methods such as coating, spraying, and dipping can be used as contact methods. More specifically, known methods such as dip coating, spray coating, roll coating, spin coating, and bar coating can be used.

[0073] The temperature during processing in step 1 is not particularly limited, and is, for example, 10 to 70°C. Preferably, it is 20 to 70°C, more preferably 25 to 50°C, and even more preferably 30 to 40°C.

[0074] The processing time in step 1 varies depending on the processing temperature, but is, for example, 10 to 600 seconds, preferably 20 to 300 seconds, and more preferably 30 to 150 seconds.

[0075] It is preferable to perform a smut removal treatment (step 2) on the aluminum material obtained in step 1 after step 1. This can further improve water repellency.

[0076] Any treatment solution that dissolves insoluble metals can be used as the smut removal treatment solution, and in this invention, an acid is used. As the acidic treatment solution, for example, hydrochloric acid, nitric acid, sulfuric acid, etc., can be used, and nitric acid is preferably used. The concentration of the acid is, for example, 50 to 500 g / L, preferably 100 to 300 g / L.

[0077] The smut removal treatment conditions are not particularly limited, but any method that allows sufficient contact between the aluminum material to be treated and the acidic treatment solution is acceptable. Typically, immersion of the metal material in the treatment solution allows for efficient treatment. While the treatment conditions are not particularly limited, for example, when using the immersion method, the temperature of the treatment solution should be around 10 to 90°C, and the immersion time should be around 5 seconds to 20 minutes.

[0078] The cycle between step 1 and step 2 is preferably performed multiple times (for example, twice). This can further improve water repellency.

[0079] After the completion of steps 1 and 2, other processes, such as anodizing (step 3), can be performed. Even after performing step 3, the water-repellent properties can be maintained. In step 3, the aluminum material is electrically brought into contact with the anode of an anodizing apparatus and immersed in an electrolyte solution together with the anode and cathode, and an anodic oxide film is formed on the aluminum molded body by passing an electric current between the anode and the cathode.

[0080] The electrolyte used in this process consists of sulfuric acid, maleic acid, malonic acid, oxalic acid, phosphoric acid, etc., but sulfuric acid is particularly preferred due to its versatility. However, it is not limited to these.

[0081] Anodizing is performed by immersing the aluminum material in a bath containing the above-mentioned acid at a concentration of 1 to 20% by weight, while maintaining a constant current density. Preferably, the current density is a constant current of 0.2 to 3.0 A / dm², and this treatment is carried out for approximately 15 to 120 minutes. However, these conditions are not limited to those described above; any conditions that allow for film formation are acceptable.

[0082] The thickness of the anodic oxide film is not particularly limited, but is 5 to 50 μm in the thickness direction from the aluminum surface, and is preferably 8 to 20 μm.

[0083] After step 3 is completed, other processes, such as a sealing process (step 4), can be performed. Even after performing step 4, the water-repellent properties can be maintained. In step 4, the pores in the anodic oxide coating can be closed and protected by immersing the aluminum material in a sealing solution.

[0084] The sealing method is not particularly limited, and any known method or a method similar to it may be used. Examples of sealing methods include sealing with boiling water, sealing with a metal-containing aqueous solution, and sealing with nickel metal salts such as nickel acetate or nickel fluoride. Among these, sealing with nickel fluoride is preferred. However, the method is not limited to these.

[0085] The temperature conditions for the sealing treatment are not particularly limited; for example, the sealing treatment can be performed at 5 to 100°C. When a metal salt is added, its concentration in the sealing solution is preferably 0.01 to 3% by mass. The treatment time can usually be determined by the thickness of the anodic oxide film to be treated. Specifically, it is preferable to use a value obtained by multiplying the numerical value indicating the film thickness (unit: μm) by 0.5 to 3 as the sealing treatment time (minutes). For example, if the thickness of the anodic oxide film is 10 μm, the sealing time is preferably 5 to 30 minutes, which is 10 multiplied by 0.5 to 3. However, these conditions are not limiting, and any conditions that allow sealing are acceptable.

[0086] After the completion of step 2, the cycle between step 1 and step 2, step 3, or step 4, other treatments, such as rust prevention treatment (step 5), can be performed. Performing step 5 allows the water repellency to be maintained at a certain level or higher immediately after treatment (or improved), and the water repellency to be maintained for a longer period of time. In step 5, the aluminum material is protected from dirt, corrosion, etc., by immersing it in a rust-preventive solution.

[0087] The rust prevention method is not particularly limited, and methods following or similar to known methods can be employed. Examples of rust inhibitors widely used include inorganic chromates, molybdates, tungstates, and nitrites, as well as organic triazole compounds, imidazole compounds, thiourea compounds, amine benzoate compounds, ammonium benzoate compounds, ammonium cyclohexane carboxylate compounds, anionic surfactants, cationic surfactants, betaine surfactants, nonionic surfactants, and ester compounds. Among these, anionic surfactants are preferred, with versatile phosphate-type anionic surfactants, perfluoroalkyl group-containing carboxylic acid-type anionic surfactants, and succinic acid-type anionic surfactants being more preferred. However, the method is not limited to these. The rust inhibitor can be used individually or in combination of two or more types.

[0088] The temperature conditions for rust prevention treatment are not particularly limited; for example, rust prevention treatment can be performed at 5 to 100°C. The concentration of the rust inhibitor component in the liquid is, for example, 0.001 to 100 g / L, preferably 0.1 to 10 g / L. The treatment time can be 5 seconds to 30 minutes. However, these conditions are not limited either; any conditions that enable rust prevention are acceptable.

[0089] According to the method of the present invention, it is possible to improve water repellency (preferably by imparting high water repellency or superhydrophobicity) without going through a film formation step. From this viewpoint, in one embodiment of the method of the present invention, it is preferable that the method does not include any film formation steps other than step 4 (for example, a step of forming a film containing a compound having a water-repellent functional group such as a trifluoromethyl group).

[0090] In another embodiment of the present invention, as described above, it is preferable to perform step 5 in order to maintain (or improve) the water repellency immediately after treatment to a certain level or higher, and to maintain the water repellency for a longer period of time.

[0091] After each of the processes in steps 1 to 5, it is preferable to rinse with water as needed.

[0092] After the above treatment is completed, it is preferable to perform a drying treatment to facilitate the development of water repellency. The drying temperature is, for example, around 20 to 100°C, preferably around 40 to 100°C, and more preferably around 60 to 100°C. The drying time varies depending on the drying temperature, but for example, at a relatively low temperature (e.g., 20 to 40°C), it can be about 20 to 50 days, and at a relatively high temperature (e.g., 60 to 100°C), it can be about 24 to 72 hours. Furthermore, the drying efficiency can be further improved by immersing the aluminum material in a volatile organic solvent such as acetone before performing the drying treatment. [Examples]

[0093] The present invention will be described in detail below based on examples, but the present invention is not limited to these examples.

[0094] Test Example 1. Etching treatment of aluminum material Degreasing was performed by wiping both sides of the aluminum test piece (JIS A1050P material, 10cm x 5cm, double-sided) with a paper towel soaked in acetone. Next, the test piece was washed with water and immersed for 90 seconds in an alkaline etching solution of the composition and temperature shown in Tables 1-4 (Comparative Examples 1-4 and Examples 1-33). Furthermore, the test piece was washed with water and immersed for 10 minutes in an acidic etching solution (Desmatt solution) at 60°C (Top Desmatt N-20, manufactured by Okuno Pharmaceutical Co., Ltd.: 100 ml / L, 62% nitric acid: 200 ml / L). After that, it was washed with water again. For Examples 12-33 in Tables 2-4, the above alkaline etching treatment and smut removal treatment cycle was repeated one more time (total of two times).

[0095] The test specimens were immersed in acetone at room temperature for 1 hour, then removed and dried in a vacuum dryer heated to 80°C for 48 hours. During drying, the test specimens were stored upright to prevent overlapping.

[0096] Test Example 2. Anodizing Treatment The test specimens from Example 21, after etching (Test Example 1), were subjected to various anodic oxidation treatments under the conditions shown in Table 5, so that the thickness of the anodic oxide film was 10 μm.

[0097] Test Example 3. Sealing Treatment For the test specimens of Example 34 after anodizing treatment (Test Example 2), various sealing treatments were performed under the conditions shown in Table 6 that could seal the anodic oxide film.

[0098] Test example 4. Rust prevention treatment Aluminum test specimens (JIS A6063 material, 10cm x 5cm, double-sided) were subjected to etching treatment in Example 21, anodic oxidation treatment in Example 34, and sealing treatment in Example 41, similar to Test Examples 1-3. Subsequently, the test specimens were treated with rust prevention treatment under the conditions shown in Table 7.

[0099] Water repellency evaluation The contact angle of the test specimen was measured using the "Kyowa Interface Science Co., Ltd.: Automatic Contact Angle Meter DM-301". The "32G needle" was used, and the contact angle was evaluated when 1 μl of water droplet was dropped onto the test specimen.

[0100] Bath stability evaluation After etching with the etching solutions of Comparative Examples 2-4 and Examples 1-33, the solutions were left at 25°C for 24 hours. Bath stability was evaluated based on the presence or absence of precipitation during this time.

[0101] Durability evaluation The prepared test specimens were suspended in a 2L beaker containing 100ml of deionized water and left under sealed, humid conditions at 25°C. The contact angle was measured after one and two weeks in the same manner as described above.

[0102] result The results are shown in Tables 1-7.

[0103] [Table 1]

[0104] [Table 2]

[0105] [Table 3]

[0106] [Table 4]

[0107] [Table 5]

[0108] [Table 6]

[0109] Table 7

Claims

1. An etching solution for improving the water repellency of aluminum materials, containing an alkali, a zinc ion source, and a salt of a transition metal other than zinc.

2. The etching solution according to claim 1, wherein the alkali is an alkali metal hydroxide.

3. The etching solution according to claim 1 or 2, wherein the transition metal salt other than zinc is at least one selected from the group consisting of iron salts, copper salts, nickel salts, and silver salts.

4. Etching solution according to any one of claims 1 to 3, wherein the concentration of the transition metal salt other than zinc is 0.1 to 100 g / L.

5. The etching solution according to any one of claims 1 to 4, further containing an amine compound.

6. The etching solution according to claim 5, wherein the amine compound is at least one selected from the group consisting of dimethylamine-epichlorohydrin copolymer, monoethanolamine, ethylenediamine, and polyethyleneimine.

7. The etching solution according to any one of claims 1 to 6, further containing a stabilizer.

8. The etching solution according to claim 7, wherein the stabilizer is at least one selected from the group consisting of carboxylic acids and salts thereof.

9. The etching solution according to claim 7 or 8, wherein the stabilizer is at least one selected from the group consisting of hydroxycarboxylic acids, aromatic carboxylic acids, and salts thereof.

10. The etching solution according to any one of claims 7 to 9, wherein the stabilizer is at least one selected from gluconic acid, tartaric acid, malic acid, citric acid, salicylic acid, salicylic acid derivatives, phthalic acid, γ-resorcylic acid, and salts thereof.

11. An etching solution according to any one of claims 1 to 10, for use in alkaline etching in an aluminum material processing method that performs alkaline etching and smut removal.

12. An etching solution for aluminum materials, containing an alkali, a zinc ion source, a salt of a transition metal other than zinc, and an amine compound.

13. (Step 1) A step of treating an aluminum material with an etching solution according to any one of claims 1 to 12. A method for improving the water repellency of aluminum materials, including [specific component].

14. moreover, (Step 2) A step of removing smut from the aluminum material after step 1. The method according to claim 13, including the method described in claim 13.

15. The method according to claim 14, wherein the cycle of step 1 and step 2 is performed multiple times.

16. moreover, (Step 3) After Step 2 or after the end of the cycle, an aluminum material is subjected to anodizing treatment. The method according to claim 14 or 15, including the method described in claim 14 or 15.

17. moreover, (Step 4) A step of sealing the aluminum material after step 3. The method according to claim 16, including the method described in claim 16.

18. moreover, (Step 5) After step 2, after the end of the cycle, after step 3, or after step 4, a step to apply rust prevention treatment to the aluminum material. The method according to any one of claims 14 to 17, including the method described above.

19. (Step 1) A step of treating an aluminum material with an etching solution according to any one of claims 1 to 12. A method for producing an aluminum material with improved water repellency, including [a specific component].

Images