JP7452826B1 - Method for producing aluminum having a surface treatment film, aluminum having a surface treatment film, and container at least partially composed of aluminum having a surface treatment film - Google Patents

Abstract

[Problem] Even if an object is brought into contact with aluminum that has an oxide film formed on its surface and the fine pores or fine irregularities of the oxide film are impregnated with iodine or an iodine compound, the characteristic color and odor of iodine will not easily adhere to the object. The goal is to make it happen. [Solution] A method for manufacturing aluminum having a surface treatment film includes an anodizing treatment in which an oxide film having fine pores is formed on the surface of aluminum, and iodine in which the fine pores are impregnated with iodine by electrophoretic electrodeposition of iodine. It performs impregnation treatment and oxide film sealing treatment. In the anodizing treatment, an oxide film having a thickness of 10 to 50 μm is formed in a sulfuric acid electrolyte at a temperature of 5 to 15° C. and a sulfuric acid concentration of 15 to 25 wt%. In the iodine impregnation treatment, an electrolytic voltage of 30 to 110 V is applied for 1 to 5 minutes to a solution of iodine or an iodine compound whose iodine content is 1.0 to 5.0 wt%. [Selection diagram] Figure 1

Description

Embodiments of the present invention relate to a method for producing aluminum having a surface treatment film, aluminum having a surface treatment film, and a container at least partially made of aluminum having a surface treatment film.

A process of forming an oxide film on the surface of aluminum using an electrolyte such as a sulfuric acid electrolyte or an oxalic acid electrolyte is known as alumite. Furthermore, aluminum oxide (Al ₂ O ₃ ) itself, which is formed as an oxide film on the surface of aluminum, is often called alumite. The main purposes of anodizing (alumite) treatment include improving corrosion resistance, coloring, imparting lubricity and wear resistance, and electrical insulation.

When aluminum is anodized, fine holes or irregularities are created on the surface. For this reason, after the anodic oxidation treatment, a sealing treatment is usually performed to close fine holes or irregularities. Sealing treatments include pressurized steam sealing in a high-pressure container using pressurized steam, boiling water sealing in boiling water, and nickel acetate addition sealing in an aqueous solution of nickel acetate. is typical.

Furthermore, a technique is known in which microscopic pores or irregularities formed in the oxide film of a metal containing aluminum are impregnated with iodine or an iodine compound to impart bactericidal and antibacterial properties (see, for example, Patent Document 1). As a practical example, after anodizing aluminum, the micropores of the oxide film are impregnated with polyvinylpyrrolidone iodide (PVPI), an easily available iodine compound, by electrophoretic electrodeposition. Materials with bactericidal and antibacterial properties can be produced by this method. Note that PVPI is also called povidone iodine.

The method described in Patent Document 1 is a technique in which no sealing treatment is performed after impregnation with PVPI, that is, a technique in which a film structure in which PVPI is exposed to the outside is formed. This is because if sealing treatment is performed after impregnation with PVPI, PVPI, which exhibits bactericidal and antibacterial properties, will be trapped in the micropores or fine irregularities of the oxide film immediately after the sealing treatment, whereas conventional This is because if a sealing treatment using a sealant is performed, iodine will dissolve into the sealant and cause discoloration.

Therefore, a technique has been proposed in which, after impregnation with PVPI, a sealing treatment is performed so that PVPI is partially exposed (see, for example, Patent Document 2). The method described in Patent Document 2 involves at least performing a low-temperature sealing treatment after impregnating PVPI mixed with a dye into the micropores or micro-irregularities of the oxide film by immersion dyeing or by impregnating PVPI by electrophoretic electrodeposition. and, if necessary, high-temperature sealing treatment.

Low-temperature sealing treatment involves immersing a base material on which an oxide film has been formed in a low-temperature sealing liquid containing nickel fluoride or nickel acetate as a main component, thereby creating fine pores to the extent that PVPI can at least vaporize and diffuse. Alternatively, it is a sealing treatment that partially closes fine irregularities, and high-temperature sealing treatment is said to be a sealing treatment that completely closes fine pores or fine irregularities to a state where there is no vaporization or dissipation of PVPI. It is said that vaporization of PVPI can be suppressed by sealing treatment including at least low-temperature sealing treatment and weather resistance can be exhibited.

In addition, Patent Document 2 describes that by mixing PVPI with a sealing agent, PVPI can be diffused not only within the micropores or microscopic irregularities but also from the film-like pore sealing portion. Therefore, even if high-temperature sealing treatment is performed, PVPI will diffuse from the film-like sealing part, and after the film-like sealing part is worn out, PVPI in the micropores or fine irregularities will diffuse. It is said that by doing so, bactericidal and antibacterial properties are continuously exhibited.

In addition, there is a method in which coloring with an organic dye or electrolytic coloring is performed prior to impregnation of an iodine compound by electrophoretic electrodeposition into the fine pores or fine irregularities of the oxide film (for example, see Patent Document 3), and a method in which trimethyl sulfur is used as an iodine compound. Methods using trimethylsulfoxonium iodide (TMSOI) or trimethylsulfonium iodide (TMSI) are also known (see, for example, Patent Documents 4 to 6).

It should be noted that in the method described in Patent Document 3, it is understood that no sealing treatment is performed after impregnation with an iodine compound, while in the methods described in Patent Documents 4 to 6, a sealing agent is used. Sealing treatment, sealing with hot water at 80°C or higher without using a sealing agent, or immersing the oxide film in an aqueous solution of iodine compound at 85°C or higher to seal the pores while impregnating them with an iodine compound. processing is possible.

Japanese Patent Application Publication No. 2000-054194 Japanese Patent Application Publication No. 2005-350741 Japanese Patent Application Publication No. 2001-169996 Japanese Patent Application Publication No. 2012-197481 Japanese Patent Application Publication No. 2012-197482 JP2014-047380A

When aluminum, which has an oxide film formed on its surface and impregnated with iodine or an iodine compound in the fine pores or irregularities of the oxide film as described above, comes into contact with an object, the reddish-brown color of iodine may adhere to the object. be. That is, the reddish-brown color characteristic of iodine may fade. In addition, not only does the odor of iodine occur, but the odor of iodine may be transferred to objects. As a result, there is a problem in that it becomes difficult to construct containers, utensils, etc. using aluminum on which an oxide film is formed and the fine pores or fine irregularities of the oxide film are impregnated with iodine or an iodine compound.

On the other hand, sealing with a low-temperature sealing liquid containing nickel fluoride or nickel acetate as the main ingredients reduces the possibility of the iodine color adhering to the object or the iodine odor being transferred to the object. Although some proposals have been made that nickel and nickel oxides can be used, there is a problem in that nickel and nickel oxides are reported to be harmful to the human body, or at least suspected to be harmful to the human body. For this reason, when there is a need not to use nickel, as typified by medical instruments, it is not possible to perform a sealing process using a sealing liquid.

On the other hand, the iodine compounds TMSOI and TMSI are very expensive compared to PVPI. Therefore, it is desirable to use easily available PVPI as the iodine compound.

Therefore, regardless of the type of iodine compound, even if an object is brought into contact with aluminum on which an oxide film is formed on the surface and the fine pores or fine irregularities of the oxide film are impregnated with iodine or an iodine compound, the object The purpose is to make it difficult for colors and odors peculiar to iodine or iodine compounds to adhere to the surface of the product.

Another object of the present invention is to bring an object into contact with aluminum, which has an oxide film formed on its surface and impregnated with iodine or an iodine compound into the fine pores or fine irregularities of the oxide film, regardless of the type of iodine compound. The object of the present invention is to make it difficult for the colors and odors characteristic of iodine or iodine compounds to adhere to objects without using nickel.

A method for manufacturing aluminum having a surface treatment film according to an embodiment of the present invention includes an anodizing treatment to form an oxide film having fine holes or recesses on the surface of aluminum, and a method for forming an oxide film having fine holes or recesses on the surface of aluminum; The method includes an iodine impregnation treatment in which iodine or an iodine compound is impregnated, and a sealing treatment of the oxide film after the iodine impregnation treatment, and the sealing treatment includes hot water sealing using hot water of 60°C or more and less than 80°C. It is used to make holes.

Further, the aluminum having a surface treatment film according to an embodiment of the present invention includes an oxide film having fine holes or recesses as the surface treatment film, and iodine or an iodine compound impregnated in the fine holes or recesses. The oxide film has a sealing degree of 40 μS or more and 60 μS or less as determined by an admittance measurement test.

Further, the aluminum having a surface treatment film according to an embodiment of the present invention includes an oxide film having fine holes or recesses as the surface treatment film, and iodine or an iodine compound impregnated in the fine holes or recesses. , and bayerite precipitated in the fine holes or recesses.

Further, the container according to the embodiment of the present invention is configured at least in part of aluminum having the above-mentioned surface treatment film.

1 is a flowchart showing the steps of a method for manufacturing aluminum having a surface treatment film according to a first embodiment of the present invention. FIG. 2 is a schematic diagram showing the detailed structure of aluminum having a surface treatment film manufactured by the manufacturing method shown in FIG. 1. FIG. FIG. 2 is a table showing the relationship between the temperature of the electrolytic solution and the state of the surface treatment film in the anodizing treatment shown in FIG. 1. FIG. FIG. 2 is a table showing the relationship among the current application time, the sealing method, and the state of the surface treatment film in the iodine impregnation treatment shown in FIG. 1. FIG. 3 is a flowchart showing the steps of a method for manufacturing aluminum having a surface treatment film according to a second embodiment of the present invention. 6 is a table comparing the state of the surface treatment film after hot water sealing shown in FIG. 5 with the state of the surface treatment film after other sealing treatments. 6 is a table showing the relationship between the hot water sealing treatment time shown in FIG. 5 and the state of the surface treatment film. 3 is a flowchart showing the steps of a method for manufacturing aluminum having a surface treatment film according to a third embodiment of the present invention. 7 is a flowchart showing the steps of a method for manufacturing aluminum having a surface treatment film according to a fourth embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A method for producing aluminum having a surface treatment film, an aluminum having a surface treatment film, and a container at least partially made of aluminum having a surface treatment film according to embodiments of the present invention will be described with reference to the accompanying drawings.

(First embodiment)
FIG. 1 is a flowchart showing the steps of a method for manufacturing aluminum having a surface treatment film according to a first embodiment of the present invention.

As shown in FIG. 1, the method for producing aluminum with a surface treatment film includes a step P1 of performing pretreatment, a step P2 of performing anodization (alumite) treatment, a step P3 of performing iodine impregnation treatment by electrophoretic electrodeposition, and a step P3 of performing iodine impregnation treatment by electrophoretic electrodeposition. It includes a step P4 of performing hole treatment and a step P5 of drying.

In the pretreatment in step P1, known treatments such as degreasing, etching, and smut removal are performed. Degreasing is a process in which oil is removed by cleaning the surface of aluminum using a solvent, alkali, acid, or the like. Etching is a process that removes scratches and removes oil remaining after degreasing by dissolving the surface of aluminum using an alkaline solution such as a sodium hydroxide solution. Smut removal is a process in which residues remaining on the aluminum surface during etching are removed using a nitric acid solution or the like. In addition to the pretreatment, chemical polishing or chemical polishing may be performed.

The anodizing treatment in step P2 is a treatment in which an oxide film having fine holes or recesses is formed on the surface of aluminum by electrolysis. Specifically, aluminum is immersed in an acidic aqueous solution to serve as an anode, and an oxide film is formed on the surface of the aluminum by applying electricity.

In the anodizing treatment in step P2, the temperature is 5°C or more and 15°C or less, and the concentration of sulfuric acid is 15wt% or more and 25wt% or less so that an oxide film having a thickness of 10μm or more and 50μm or less is formed. It is carried out in a solution of sulfuric acid.

The iodine impregnation treatment in step P3 is a treatment in which fine pores or recesses of the oxide film are impregnated with iodine or an iodine compound by electrophoretic electrodeposition of iodine or an iodine compound. Therefore, the anodizing treatment in step P2 corresponds to primary electrolytic treatment, and the iodine impregnation treatment in step P3 corresponds to secondary electrolytic treatment.

A representative example of an easily available iodine compound is PVPI, but electrophoresis may be performed using TMSOI, TMSI, other iodine compounds, or iodine alone. Depending on the type of iodine compound, there are cases where only iodine is electrodeposited into the fine pores or recesses of the oxide film, and cases where the iodine compound is electrodeposited into the fine pores or recesses of the oxide film.

The iodine impregnation treatment in step P3 is performed by applying an electrolytic voltage of 30 V to 110 V to a solution of iodine or an iodine compound whose iodine content is 1.0 wt% or more and 5.0 wt% or less for 1 minute or more and 5 minutes or less. This is done by applying only the electrolytic time.

The sealing treatment in step P4 is a treatment for closing fine pores or recesses in the oxide film after the iodine impregnation treatment. Typical types of sealing treatment include pressurized steam sealing, boiling water sealing, and nickel salt sealing, but pressurized steam sealing is not employed. This is because tests have confirmed that when pressurized steam sealing is performed, iodine leaks out from minute pores or recesses in the oxide film, causing unevenness.

When sealing is performed using a method other than pressurized steam sealing, the fine pores or recesses in the oxide film will not be completely closed even if the sealing treatment is performed. The recess will be partially closed. The degree to which fine pores or recesses in the oxide film are blocked is evaluated using the degree of sealing as an index. There are multiple sealing tests to determine the sealing degree, such as a staining liquid drip test, a phosphoric acid-chromic acid aqueous solution immersion test, and an admittance measurement test, and the sealing degree has a different value for each sealing degree test.

If a sealing method with a high degree of sealing is adopted, it will lead to improvement in the corrosion resistance of the oxide film, which is the original purpose of the sealing treatment. On the other hand, if a sealing method with a low degree of sealing is adopted, the amount of iodine leaking out from the minute pores or recesses of the incompletely sealed oxide film will increase, which will improve the bactericidal and antibacterial effects of iodine. Connect. Therefore, the sealing method can be selected according to the properties required of the aluminum having the surface treatment film.

Nickel salt sealing is a sealing process in which fine holes or recesses are closed by immersing an oxide film in a sealing liquid whose main component is a nickel salt such as nickel fluoride or nickel acetate. As a typical example, when sealing is performed in a sealing liquid made of an aqueous solution of nickel acetate, the temperature of the sealing liquid is typically set to 95°C or higher, and an oxide film is added to the sealing liquid for 10 minutes. The pore sealing process is performed by soaking for about 20 minutes.

In addition, sealing treatments using cobalt salts such as cobalt acetate as metal salt sealing other than nickel salt sealing are also known. If nickel salt sealing such as nickel acetate sealing or cobalt salt sealing is employed, in addition to the bactericidal and antibacterial effects of iodine, the bactericidal and antibacterial effects of nickel or cobalt can be obtained.

Boiling water sealing is a sealing process in which fine holes or recesses are closed by immersing an oxide film in hot water of 80°C or higher, typically 95°C to 100°C. If boiling water sealing is employed, the aluminum surface treatment film after sealing treatment will not contain nickel element. Therefore, if boiling water sealing is adopted, aluminum with a surface treatment film can be used as a material for medical instruments and medical parts, where nickel, which is suspected to be harmful to the human body, cannot be used. .

Conversely, the degree of sealing achieved by metal salt sealing such as nickel salt sealing is higher than that achieved by boiling water sealing. Therefore, if importance is placed on the corrosion resistance of aluminum having a surface treatment film, metal salt sealing may be employed.

In addition, after actually performing anodization treatment and iodine impregnation treatment under the above-mentioned treatment conditions, the sealing was determined in the admittance measurement test when only nickel salt sealing was performed and when only boiling water sealing was performed. The degree of The admittance measurement test is a sealing degree test in which the measured value of admittance in the oxide film is taken as the sealing degree. The unit of admittance measurement is Siemens [S], and Siemens [S] is the reciprocal of ohm [Ω], which is the unit of electrical resistance and impedance ([S] = [1/Ω]). .

As a result of the admittance measurement test, the sealing degree was 20.0 μS when nickel salt sealing was performed for 5 minutes, and 30.0 μS when boiling water sealing was performed for 5 minutes with hot water at 85°C. became. The degree of sealing measured by the admittance measurement test indicates that the smaller the measured value [S] is, the higher the degree of sealing [%] is. For example, when pressurized steam sealing, which provides the highest sealing degree, is performed, the sealing degree reaches around 0 μS. Therefore, the results of the admittance measurement test also confirm that the sealing degree [%] by nickel salt sealing is higher than the sealing degree [%] by boiling water sealing.

As the sealing process, a two-stage sealing process in which different sealing processes are performed twice is also known. Therefore, if it is particularly desirable to improve the degree of sealing and corrosion resistance, boiling water sealing may be performed after metal salt sealing such as nickel acetate sealing.

When the sealing treatment in step P4 is completed, the surface of the oxide film is washed with pure water. For this reason. In the subsequent step P5, natural drying or hot air drying is performed.

Next, the detailed structure of aluminum having a surface treatment film produced by the above-mentioned production method will be explained.

FIG. 2 is a schematic diagram showing the detailed structure of aluminum 2 having a surface treatment film 1 manufactured by the manufacturing method shown in FIG.

As shown in FIG. 2, a surface treatment film 1 is formed on the surface of aluminum 2, which is a base material. The surface treatment film 1 includes an oxide film 4 having fine pores or recesses 3, iodine or an iodine compound 5 impregnated in the fine pores or recesses 3, and precipitation near the openings of the fine pores or recesses 3. The structure has a pore sealing layer 6.

Typically, as illustrated in FIG. 2, the shape in the longitudinal section is U-shaped, and the central axis and depth direction are generally perpendicular to the surface of the oxide film 4. It is believed that pores 3 are formed in the oxide film 4. It is believed that iodine or iodine compound 5 is deposited on the inner surface of blind hole 3. On the other hand, most of the sealing layer 6 is considered to be deposited mainly in the vicinity of the opening of the blind hole 3 from the inner surface of the blind hole 3 toward the central axis of the blind hole 3 .

However, depending on the conditions of the anodic oxidation treatment, the shape in the longitudinal section may be V-shaped, etc., and many minute recesses whose central axis and depth direction are generally perpendicular to the surface of the oxide film 4 may be oxidized. It is thought that it may be formed on the film 4 in some cases. Even in that case, iodine or iodine compound 5 is precipitated on the inner surface of the recess, and most of the sealing layer 6 is precipitated from the inner surface of the recess toward the central axis of the recess, mainly near the opening of the recess. Conceivable.

Even if the oxide film 4 is sealed, the sealing degree will not be 100% unless pressurized steam sealing is performed. That is, the oxide film 4 is not completely sealed, but is in a semi-sealed state. Specifically, the fine holes or recesses 3 are incompletely closed by the sealing layer 6. In other words, fine gaps that are narrower than the fine holes or the openings of the recesses 3 remain in the sealing layer 6, and the size of the fine gaps corresponds to the degree of sealing.

Therefore, iodine or iodine compound 5 passes through the fine gaps in the sealing layer 6 and diffuses to the outside of the surface treatment film 1. As a result, a bactericidal effect and an antibacterial effect can be obtained by the iodine or iodine compound 5 leaking from the fine holes or recesses 3. Therefore, at least a part of a container such as a vessel or a box can be constructed from the aluminum 2 having the surface treatment film 1. That is, aluminum 2 having surface treatment film 1 can be used as a material for the container.

The composition of the sealing layer 6 depends on the type of sealing treatment. For example, in the case of performing nickel salt sealing, one or both of nickel and nickel salt is deposited as the sealing layer 6. On the other hand, when boiling water sealing is performed, boehmite (Al ₂ O ₃ .H ₂ O) is formed as the sealing layer 6 .

(effect)
FIG. 3 is a table showing the relationship between the temperature of the electrolytic solution in the anodizing treatment shown in FIG. 1 and the state of the surface treatment film.

The table in Figure 3 shows the results of PVPI with an iodine content of 3.0 wt% after aluminum was anodized in a sulfuric acid solution with a concentration of 20 wt% to form an oxide film with a thickness of 30 μm. This figure shows the state of the surface treatment film obtained when iodine was electrophoretically deposited by applying a voltage to the solution for 3 minutes.

As shown in the table in Figure 3, the electrolyte temperature during the anodizing treatment performed as the primary electrolysis and the electrolytic voltage during the electrophoretic electrodeposition of iodine performed as the secondary electrolysis were varied, and the state of the oxide film and the iodine The state of precipitation of iodine and the amount of iodine precipitated were investigated. More specifically, the electrolyte temperature for the anodizing treatment was varied from 5°C to 30°C in 5°C increments. On the other hand, the electrolytic voltages during electrophoretic electrodeposition were 30V, 50V, 80V, and 100V. In the table of FIG. 3, ◯ indicates that the quality is good, △ indicates that the quality is within the acceptable range, and × indicates that the quality is outside the acceptable range.

As a result of surface treatment tests, it was found that when the electrolyte temperature for anodizing treatment exceeds 15° C., an excessive amount of iodine is deposited by electrophoretic electrodeposition of iodine. In addition, it has been found that excessive precipitation of iodine leads to unfavorable iodine precipitation conditions, such as unevenness. If the amount of iodine precipitated is excessive, the color and odor of iodine will adhere to objects that come into contact with or come close to the surface of the surface treatment film.

For this reason, when performing anodization treatment to form an oxide film with a thickness of 10 μm or more and 50 μm or less in a sulfuric acid electrolyte with a sulfuric acid concentration of 15 wt% or more and 25 wt% or less, the electrolysis temperature should be 5°C or more. By setting the temperature to 15° C. or lower, excessive precipitation of iodine can be avoided. As a result, it is possible to avoid or reduce the adhesion of the color and odor of iodine to objects that come into contact with or come close to the surface of the surface-treated film. This is considered to be the same even when an iodine compound is precipitated.

In addition, as shown in the table in Figure 3, when the electrolytic temperature for anodizing treatment is set to 5°C or more and 15°C or less, the appropriate range of electrolytic voltage when performing electrophoretic electrodeposition of iodine as iodine impregnation treatment is From the viewpoint of avoiding excessive precipitation of iodine, it was also found that the voltage is 30 V or more and 110 V or less. This is considered to be the same even when an iodine compound is precipitated.

FIG. 4 is a table showing the relationship among the current application time, the sealing method, and the state of the surface treatment film in the iodine impregnation treatment shown in FIG.

The table in Figure 4 shows that after aluminum was anodized in a sulfuric acid solution with a concentration of 20 wt% at a temperature of 10°C to form an oxide film with a thickness of 30 μm, the iodine content was 3.0 wt%. This figure shows the state of the surface treatment film obtained when iodine was electrophoretically deposited by applying a voltage of 100 V to a PVPI solution.

As shown in the table in Figure 4, the state of the surface treatment film was investigated by changing the current application time during electrophoretic electrodeposition of iodine, which is performed as secondary electrolysis, and the sealing method after electrophoretic electrodeposition of iodine. . More specifically, the current application time during electrophoretic electrodeposition of iodine was set to 1 minute, 3 minutes, 5 minutes, and 10 minutes. On the other hand, in addition to sealing using nickel salt sealing, boiling water sealing using hot water at 85℃, and hot water sealing using hot water at 75℃, the surface was also sealed when no sealing treatment was performed. The condition of the treated film was examined.

The state of the surface treatment film includes the color tone or appearance of the film surface immediately after electrophoretic electrodeposition of iodine and before sealing treatment, as well as the subsequent state of iodine elution after sealing treatment or when no sealing treatment is performed. , the degree of powder blowing, the degree of decolorization, and the degree of iodine odor were evaluated. In the table of FIG. 4, ◯ indicates that the quality is good, △ indicates that the quality is within the acceptable range, and × indicates that the quality is outside the acceptable range. Moreover, the evaluation results in the case of unsealed holes represent the evaluation results after cleaning using pure water at room temperature to remove impurities.

As a result of the surface treatment test, no effective increase in the amount of iodine deposited could be confirmed even when the electrolysis time during electrophoretic electrodeposition of iodine exceeded 5 minutes. That is, even when a voltage of 100 V was applied to the PVPI solution for more than 5 minutes, no change in color tone due to iodine could be observed, and excessive precipitation of iodine only increased.

Therefore, as an iodine impregnation treatment, electrophoresis of iodine or iodine compounds is carried out by applying an electrolytic voltage of 30 V or more and 110 V or less to a solution of iodine or iodine compounds whose iodine content is 1.0 wt% or more and 5.0% or less. When performing electrodeposition, it is appropriate to apply the electrolytic voltage for an electrolysis time of 1 minute or more and 5 minutes or less from the viewpoint of avoiding excessive precipitation of iodine. That is, by setting the energization time for the secondary electrolytic treatment to 1 minute or more and 5 minutes or less, it is possible to avoid or reduce the adhesion of the color and odor of iodine to objects that come into contact with or come close to the surface of the surface treatment film. This is considered to be the same even when an iodine compound is precipitated.

On the other hand, regarding the sealing method, the surface treatment state can be changed by changing the sealing conditions such as the type of nickel salt, the sealing time, and the sealing temperature. That is, the table of FIG. 4 shows the results of a surface treatment test when sealing was performed under certain sealing conditions and sealing methods. Therefore, depending on the sealing conditions, the results of the surface treatment test illustrated in the table of FIG. 4 may not necessarily be obtained. Therefore, by determining an appropriate sealing method and sealing treatment conditions corresponding to the required quality, aluminum having a surface treatment film that satisfies the required quality can be manufactured.

As described above, the electrolytic treatment conditions for anodizing aluminum as the primary electrolytic treatment and electrophoretic electrodeposition of iodine or iodine compounds as the secondary electrolytic treatment are appropriately determined as shown in Figure 1. By setting this, it is possible to reduce brown discoloration and odor characteristic of iodine or iodine compounds. As a result, it becomes possible to reduce or avoid adhesion of colors and odors to objects while exhibiting the bactericidal and antibacterial effects of iodine or iodine compounds.

Moreover, aluminum having a surface-treated film produced by the above-described manufacturing method can be used as a material for containers such as vessels and boxes that should avoid adhesion of color and odor to stored items. That is, when a container is made of aluminum having a surface-treated film manufactured by the above-described manufacturing method, it is possible to reduce or avoid adhesion of color or odor from the container to objects stored in the container.

(Second embodiment)
FIG. 5 is a flowchart showing the steps of a method for manufacturing aluminum having a surface treatment film according to the second embodiment of the present invention.

The method for manufacturing aluminum having a surface treatment film according to the second embodiment shown in FIG. 5 is characterized in that the conditions of the anodizing treatment and the iodine impregnation treatment are not limited, but the sealing treatment is limited to hot water sealing. This method is different from the method for manufacturing aluminum having a surface treatment film in the first embodiment. The other steps in the method for manufacturing aluminum with a surface treatment film in the second embodiment are not substantially different from the method for manufacturing aluminum in the first embodiment, so the same steps have the same reference numerals. will be added and the explanation will be omitted.

In step P2' in the second embodiment, anodizing treatment is performed similarly to step P2 in the first embodiment, but the anodizing treatment is performed in an acidic aqueous solution such as chromic acid, phosphoric acid, or oxalic acid in addition to sulfuric acid. You may also do this. Therefore, the electrolytic treatment conditions may be changed as appropriate. However, if aluminum is anodized under the same electrolytic treatment conditions as in step P2 in the first embodiment, it will be better to prevent the color and odor of iodine from adhering to objects that come into contact with or come close to the surface of the surface treatment film. can be avoided or reduced.

In step P3' in the second embodiment, iodine impregnation treatment is performed similarly to step P3 in the first embodiment. The iodine impregnation treatment may be performed by immersing it in a solution containing the iodine. However, if electrophoretic electrodeposition of iodine or an iodine compound is performed under the same electrolytic treatment conditions as in step P3 in the first embodiment, the color and odor of iodine will adhere to objects that come into contact with or come close to the surface of the surface treatment film. This can be better avoided or reduced.

In step P4' in the second embodiment, a sealing process is performed similarly to step P4 in the first embodiment, but hot water sealing is performed as the sealing process. Hot water sealing is a sealing process using hot water of 60°C or higher and lower than 80°C.

Hot water sealing, like boiling water sealing, is a sealing process that does not use metal salts such as nickel salts and cobalt salts, so hot water sealing can ensure safety for the human body. That is, aluminum having a surface treatment film can be made nickel-free. As a result, it becomes possible to use aluminum having a surface-treated film as a material for medical instruments and containers that particularly require safety for the human body.

As a result of the surface treatment test, as shown in the table of FIG. 4 mentioned in the first embodiment, when boiling water sealing is performed as the sealing treatment, sterilization may occur depending on the conditions of electrophoretic electrodeposition of iodine or iodine compounds. It has also been found that iodine, which is an antibacterial component, may be eluted, resulting in an uneven appearance or the precipitation of powdery substances.

On the other hand, as shown in the table in Figure 4, hot water sealing not only eliminates problems such as uneven appearance and powder blowing that occur when boiling water sealing is performed, but also eliminates iodine and iodine. It was found that the color and odor of the compound became difficult to remove. Therefore, although the sealing degree of hot water sealing is lower than that of boiling water sealing, hot water sealing not only reduces uneven appearance and powder precipitation, but also improves the surface of the surface treatment film. It is possible to avoid or reduce the adhesion of the color or odor of iodine or iodine compounds to objects that are touched or approached. Briefly speaking, it can be said that hot water sealing is a sealing treatment that is compatible with iodine impregnation treatment.

FIG. 6 is a table comparing the state of the surface treatment film after hot water sealing shown in FIG. 5 with the state of the surface treatment film after other sealing treatments.

The table in FIG. 6 shows that after aluminum is anodized in a sulfuric acid solution with a liquid temperature of 10°C and a concentration of 20 wt% in step P2' to form an oxide film with a thickness of 30 μm, iodine is added in step P3'. In the case where electrophoretic electrodeposition of iodine is performed by applying a voltage of 100 V for 3 minutes to a solution of PVPI whose content is 3.0 wt%, and further hot water sealing is performed in the subsequent step P4'. An example is shown in which the state of the surface treatment film is compared with cases where boiling water sealing and nickel salt sealing were performed.

More specifically, as shown in the table of Figure 6, boiling water sealing using 90°C hot water, boiling water sealing using 85°C hot water, and boiling water sealing using 80°C hot water Sealing, hot water sealing using 75°C hot water, and nickel salt sealing were performed, and the state of the surface treatment film was examined. As for the condition of the surface treatment film, the state of iodine elution, the degree of powder blowing, the degree of decolorization, and the degree of iodine odor after 12 hours were evaluated. In the table of FIG. 6, ◯ indicates that the quality is good, △ indicates that the quality is within the acceptable range, and × indicates that the quality is outside the acceptable range.

As shown in the table in Figure 6, as a result of surface treatment tests including sealing tests, the results showed that when nickel salt sealing was performed and when boiling water sealing was performed using hot water of 85°C or higher, , powder blowing occurred. It was also found that the lower the temperature of the pure water used for the sealing process, the more the iodine odor can be reduced. This means that even if the degree of pore sealing of the oxide film is low, the amount of leakage of color and odor of iodine or iodine compounds does not increase to an observable extent. However, if the temperature of the pure water becomes too low, the degree of sealing will decrease, and there is a risk that the original purpose of the sealing process, which is to impart corrosion resistance to the aluminum alloy by the oxide film, will be insufficient.

Therefore, although sealing using hot water at a temperature of 60°C or higher and lower than 80°C is classified as hot water sealing, hot water is preferable from the viewpoint of ensuring the corrosion resistance of aluminum alloys while suppressing the color and odor diffusion of iodine or iodine compounds. The temperature range is considered to be 70°C or higher and 75°C or lower. In other words, if hot water sealing is performed using hot water of 70°C or higher and 75°C or lower as a sealing treatment, the color and odor of iodine will be removed from objects that come into contact with or come close to the surface of the surface treatment film, while ensuring the corrosion resistance of the aluminum alloy. Adhesion can be better avoided or reduced.

FIG. 7 is a table showing the relationship between the hot water sealing treatment time shown in FIG. 5 and the state of the surface treatment film.

The table in FIG. 7 shows that after aluminum is anodized in a sulfuric acid solution with a liquid temperature of 10°C and a concentration of 20 wt% in step P2' to form an oxide film with a thickness of 30 μm, iodine is added in step P3'. Electrophoretic electrodeposition of iodine is performed by applying a voltage of 100 V for 3 minutes to a solution of PVPI whose content is 3.0 wt%, and then in step P4', hot water at 75°C is used to deposit iodine. It shows the state of the surface treatment film after sealing.

As shown in the table of FIG. 7, a surface treatment test including a sealing test was conducted while changing the hot water sealing treatment time. More specifically, as shown in the table of FIG. 7, the condition of the surface treatment film was examined with hot water sealing treatment times of 10 minutes, 5 minutes, 1 minute, and 10 seconds. As for the condition of the surface treatment film, the state of iodine elution, the degree of powder blowing, the degree of decolorization, and the degree of iodine odor after 12 hours were evaluated. In the table of FIG. 7, ◯ indicates that the quality is good, △ indicates that the quality is within the allowable range, and × indicates that the quality is outside the allowable range.

As shown in the table of FIG. 7, as a result of the surface treatment test including the sealing test, powder blowing occurred when the hot water sealing treatment time was set to 10 minutes. Furthermore, it was confirmed that when the hot water sealing treatment time was set to 5 minutes, iodine elution, iodine decolorization, and iodine odor, which cause uneven appearance, could be reduced the most.

Therefore, from the viewpoint of reducing the odor of iodine or iodine compounds while avoiding powder blowing, the preferable range of hot water sealing treatment time is considered to be 3 minutes or more and 7 minutes or less. In other words, if hot water sealing is performed as the sealing treatment, and the hot water sealing time is set to 3 minutes or more and 7 minutes or less, the surface treatment film can be improved while avoiding powder blowing, which is a typical problem in alumite treatment. It is possible to better avoid or reduce the adhesion of iodine odor to objects that come into contact with or come close to the surface.

When hot water sealing is employed as the sealing treatment, bayerite (Al ₂ O ₃ .3H ₂ O) is precipitated on the surface of the oxide film containing minute pores or recesses. That is, in the aluminum 2 having the surface treatment film 1 shown in FIG. 2, the composition of the sealing layer 6 is bayerite. More specifically, the sealing layer 6 made of a bayerite layer grows from the oxide film 4 made of an aluminum oxide layer near the opening of the fine hole or recess 3 toward the center of the fine hole or recess 3. It is thought that there are.

Therefore, if boehmite is not precipitated in the surface treatment film 1 and bayerite is precipitated, then hot water sealing instead of boiling water sealing was performed as the sealing treatment. Further, if bayerite is precipitated in the surface treatment film 1 and metal such as nickel is not included as an element, it means that metal salt sealing was not performed as two-step sealing.

However, it is not easy to directly determine whether bayerite or boehmite is precipitated on the surface treatment film. Therefore, a method is usually employed to indirectly determine whether bayerite or boehmite is precipitated in the surface treatment film by measuring the degree of pore sealing of the oxide film.

When boehmite is deposited on the surface of the oxide film due to boiling water sealing, as explained in the first embodiment, the degree of sealing according to the admittance measurement test is considered to be approximately 30.0 μS. The degree of sealing is considered to vary depending on sealing conditions such as sealing time and temperature of hot water.

On the other hand, when bayerite is precipitated on the surface of the oxide film due to hot water sealing, the sealing degree determined by the admittance measurement test is approximately 40μS depending on the sealing conditions such as sealing time and hot water temperature. It is thought that the time will be in the range of 60 μS or less. Therefore, if the degree of sealing of the oxide film according to the admittance measurement test is 40 μS or more and 60 μS or less, it is considered that bayerite is precipitated on the surface of the oxide film due to hot water sealing. In addition, when the degree of sealing of the oxide film was measured in an admittance measurement test when hot water sealing was actually performed for 5 minutes using hot water at 75° C., the degree of sealing was 50 μS.

As described above, in the first embodiment, the electrolytic treatment conditions of the anodic oxidation treatment and the iodine impregnation treatment are determined so that the color and odor of iodine or iodine compounds are difficult to remove. In the second embodiment, the conditions for the sealing treatment are determined so that the color and odor of iodine or iodine compounds are difficult to remove.

Therefore, according to the second embodiment, as in the first embodiment, it is possible to reduce or avoid adhesion of color and odor to objects while exhibiting the bactericidal and antibacterial effects of iodine or iodine compounds. becomes. In addition, according to the second embodiment, safety to the human body can be ensured by making the aluminum having the surface treatment film nickel-free. Therefore, aluminum having a surface treatment film can be used as a material for medical instruments and containers that require safety for the human body.

Of course, the first embodiment and the second embodiment may be combined. In other words, in addition to appropriately setting the electrolytic treatment conditions when performing the anodizing treatment of aluminum as the primary electrolytic treatment and the electrophoretic electrodeposition of iodine or iodine compounds as the secondary electrolytic treatment, the sealing treatment By sealing with hot water, the color and odor of iodine or iodine compounds may be made difficult to adhere to objects.

(Third embodiment)
FIG. 8 is a flowchart showing the steps of a method for manufacturing aluminum having a surface treatment film according to the third embodiment of the present invention.

In the method for manufacturing aluminum having a surface treatment film in the third embodiment shown in FIG. 8, after performing an iodine impregnation treatment, a decolorization and deodorization treatment that also serves as drying is performed without performing a sealing treatment for the oxide film. This is different from the method for manufacturing aluminum having a surface treatment film in the second embodiment. The other steps in the method for manufacturing aluminum with a surface treatment film in the third embodiment are not substantially different from the method for manufacturing aluminum in the second embodiment, so the same steps have the same reference numerals. The explanation will be omitted.

In the third embodiment shown in FIG. 8, in step P10 after the iodine impregnation treatment in step P3', a decolorizing and deodorizing treatment is performed to reduce the color and odor diffusion of iodine or iodine compounds to a negligible extent. The decolorizing and deodorizing treatment can be a treatment in which the iodine or iodine compound impregnated into the fine pores or recesses of the oxide film is exposed to the air, thereby diffusing the iodine or the iodine compound into the air.

As a result of the test, no noticeable improvement in the deodorizing and decolorizing effects of iodine or iodine compounds could be confirmed even when the surface of the oxide film was exposed to air for 24 hours or more at room temperature. Therefore, the decolorizing and deodorizing treatment can be a treatment in which iodine or an iodine compound impregnated into the fine pores or recesses of the oxide film is exposed to the air for 24 hours or more. However, the decolorizing and deodorizing treatment may be replaced with another treatment, or other treatments may be used together as the decolorizing and deodorizing treatment. In addition, it is not limited to decolorizing and deodorizing treatment at room temperature. At least a part of the decolorizing and deodorizing treatment using hot air may also serve as hot air drying.

When the decolorizing and deodorizing treatment is performed, as shown in the table of FIG. 4, the iodine or iodine compound is diffused into the atmosphere to the extent that the color and odor of the iodine or iodine compound are not removed. Further, problems such as iodine elution and powder blowing, which cause uneven appearance, do not occur.

The color of the surface treatment film immediately after the iodine impregnation treatment is a color according to the conditions of the iodine impregnation treatment, as illustrated in the table of Figure 4, but the color of the surface treatment film after the decolorization and deodorization treatment is light orange or yellow. becomes. Typically, when the decolorizing and deodorizing treatment is performed, the color of the surface treatment film gradually changes from brown to yellow. As a result, the color of the aluminum with the surface treatment film becomes close to gold due to the metallic luster of the base material aluminum.

As can be seen from the appearance, even after decolorizing and deodorizing treatment, a thin layer of iodine or iodine compound remains on the inner surface of the fine pores or recesses of the oxide film. As a result, the bactericidal and antibacterial effects of iodine or iodine compounds can be maintained.

Therefore, according to the third embodiment described above, while maintaining the bactericidal effect and antibacterial effect of iodine or iodine compounds, it is possible to further reduce or further reduce the color and odor of iodine or iodine compounds from being attached to objects. This can be reliably avoided. In addition, an appearance close to gold can be obtained.

In addition, if the decolorization and deodorization treatment in step P10 is performed, even if the amount of precipitated iodine or iodine compound becomes excessive due to the iodine impregnation treatment in step P3', or if iodine is eluted and uneven appearance occurs, the subsequent decolorization will be performed. During the deodorizing treatment, iodine or iodine compounds fall off from the oxide film.

Therefore, strictly speaking, unlike the second embodiment, the third embodiment prevents excessive precipitation of iodine or iodine compounds and elution of iodine in the anodizing treatment in step P2' and the iodine impregnation treatment in step P3'. Optimization of processing conditions to avoid this is not important. For example, it is important in the third embodiment to determine the electrolytic treatment conditions in the anodizing treatment and iodine impregnation treatment so that the color and odor of iodine or iodine compounds are difficult to remove, as in the first embodiment. isn't it.

(Fourth embodiment)
FIG. 9 is a flowchart showing the steps of a method for manufacturing aluminum having a surface treatment film according to the fourth embodiment of the present invention.

The method for manufacturing aluminum having a surface treatment film according to the fourth embodiment shown in FIG. 9 differs from the surface treatment film according to the third embodiment in that after decolorizing and deodorizing treatment, pore sealing treatment and drying are performed. It is different from the manufacturing method of aluminum. The steps up to the decoloring and deodorizing treatment of the method for manufacturing aluminum having a surface treatment film in the fourth embodiment are not substantially different from the method for manufacturing aluminum having a surface treatment film in the third embodiment. Further, the drying performed in the method for manufacturing aluminum having a surface treatment film in the fourth embodiment is not substantially different from the method for manufacturing aluminum having a surface treatment film in the first embodiment. Therefore, in the fourth embodiment, steps that are the same as those in the first or third embodiment are given the same reference numerals, and description thereof will be omitted.

As shown in FIG. 9, after the decolorization and deodorization treatment in step P10, a step P4'' of sealing the oxide film may be performed.In that case, drying is performed after the sealing treatment in step P4''. A process P5 is provided.

When sealing the oxide film after decolorizing and deodorizing treatment, deodorize and decolorize the iodine or iodine compound to the extent that the color and odor of the iodine or iodine compound has already been removed and does not adhere to objects before the sealing treatment of the oxide film. has been completed. Therefore, unlike the first embodiment, there are no restrictions on the conditions of the sealing treatment to make it difficult for the color and odor of iodine or iodine compounds to come off. Therefore, the sealing treatment can be performed under desired sealing conditions for the purpose of improving the corrosion resistance of the surface treatment film.

For example, aluminum with a nickel-free surface treatment film can be produced by performing boiling water sealing or hot water sealing. In particular, if boiling water sealing is performed, the degree of sealing will be higher than when hot water sealing is performed, so that the corrosion resistance of the surface treatment film can be improved.

Needless to say, it is appropriate that the oxide film sealing treatment performed after the decolorization and deodorization treatment is performed before the oxide film is corroded.

According to the fourth embodiment described above, while maintaining the bactericidal effect and antibacterial effect of iodine or iodine compounds, it is possible to further reduce or more reliably prevent the color and odor of iodine or iodine compounds from fading and adhering to objects. Not only this, but also corrosion resistance can be imparted to the surface treated film through the pore sealing treatment. In addition, by providing a decolorizing and deodorizing process that removes the color and odor of iodine or iodine compounds, excessive precipitation of iodine or iodine compounds and elution of iodine can be prevented under each treatment condition of anodizing treatment, iodine impregnation treatment, and pore sealing treatment. It is possible to avoid the occurrence of constraints to avoid the above.

(Example 1)
Aluminum was anodized as a primary electrolytic treatment in a sulfuric acid solution with a sulfuric acid concentration of 20 wt % and an electrolytic bath temperature of 10° C. to obtain aluminum having an oxide film with a thickness of 30 μm. Next, as a secondary electrolytic treatment, iodine was electrophoretically deposited in a PVPI solution with an iodine content of 3.0%. The electrolytic voltage for the secondary electrolytic treatment was 100 V, the electrolytic time for the secondary electrolytic treatment was 3 minutes, and the electrolytic bath temperature for the secondary electrolytic treatment was room temperature.

Thereafter, nickel salt sealing was performed by immersing the aluminum in a sealing liquid containing nickel acetate as a main component for 1 minute, and drying to produce aluminum having the surface treatment film of Example 1 according to the manufacturing method of the first embodiment. .

(Example 2)
Anodizing treatment of aluminum and electrophoretic electrodeposition of iodine were performed under the same conditions as in Example 1. Thereafter, hot water sealing was performed for 5 minutes using hot water at 70° C., and drying was performed to produce aluminum having the surface treatment film of Example 2 according to the manufacturing method of the second embodiment.

(Example 3)
Anodizing treatment of aluminum and electrophoretic electrodeposition of iodine were performed under the same conditions as in Example 1. After that, the aluminum having the surface treatment film of Example 3 according to the manufacturing method of the third embodiment is decolorized and deodorized by exposing it to the air for 24 hours or more without sealing the aluminum with pure water. was produced.

(Comparative example 1)
Anodizing treatment of aluminum and electrophoretic electrodeposition of iodine were performed under the same conditions as in Example 1. Thereafter, as shown in the table of FIG. 6, boiling water sealing was performed using hot water at 85° C. for 5 minutes and drying to produce aluminum having the powder-blown surface treatment film of Comparative Example 1.

(Other embodiments)
Although specific embodiments have been described above, the described embodiments are merely examples and do not limit the scope of the invention. The novel methods and apparatus described herein can be implemented in a variety of other ways. Additionally, various omissions, substitutions, and changes may be made in the methods and apparatus described herein without departing from the spirit of the invention. The appended claims and their equivalents are intended to cover such modifications and variations as fall within the scope and spirit of the invention.

1 Surface treatment film 2 Aluminum 3 Fine pores or recesses 4 Oxide film 5 Iodine or iodine compound 6 Sealing layer

Claims (11)

Anodizing treatment to form an oxide film with fine holes or recesses on the surface of aluminum;
Iodine impregnation treatment in which the fine pores or recesses of the oxide film are impregnated with iodine or an iodine compound;
A sealing treatment for the oxide film after the iodine impregnation treatment;
A method for producing aluminum having a surface treatment film, the method comprising:
A method for producing aluminum having a surface treatment film, wherein the sealing treatment is performed by hot water sealing using hot water at a temperature of 60° C. or higher and lower than 80° C. 2. The method for producing aluminum having a surface treatment film according to claim 1, wherein the sealing treatment is hot water sealing using hot water at a temperature of 70° C. or higher and 75° C. or lower. 2. The method for producing aluminum having a surface treatment film according to claim 1, wherein bayerite is precipitated in the fine pores or recesses of the oxide film without precipitating boehmite by performing the hot water sealing. 2. The method for producing aluminum having a surface treatment film according to claim 1, wherein the hot water sealing is performed so that the degree of sealing of the oxide film as determined by an admittance measurement test is set to 40 μS or more and 60 μS or less. In the anodizing treatment, an oxide film having a thickness of 10 μm or more and 50 μm or less is formed in a sulfuric acid electrolyte at a temperature of 5° C. or more and 15° C. or less and a sulfuric acid concentration of 15 wt% or more and 25 wt% or less. ,
In the iodine impregnation treatment, the fine pores or recesses of the oxide film are impregnated with the iodine or iodine compound by electrophoretic electrodeposition, and the iodine content is 1.0 wt% or more.5. Applying an electrolytic voltage of 30 V or more and 110 V or less for 1 minute or more and 5 minutes or less to the solution of iodine or iodine compound whose concentration is 0 wt% or less,
A method for producing aluminum having the surface treatment film according to claim 1. The method for producing aluminum having a surface treatment film according to any one of claims 1 to 5 , wherein the hot water sealing treatment time is 3 minutes or more and 7 minutes or less. Aluminum having a surface treatment film,
The surface treatment film is
an oxide film having fine pores or recesses;
Iodine or an iodine compound impregnated in the fine pores or recesses;
has
Aluminum having a sealing degree of 40 μS or more and 60 μS or less as determined by an admittance measurement test of the oxide film. Aluminum having a surface treatment film,
The surface treatment film is
an oxide film having fine pores or recesses;
Iodine or an iodine compound impregnated in the fine pores or recesses;
bayerite precipitated in the fine holes or recesses;
Aluminum with. The aluminum according to claim 7 or 8 , wherein the surface treatment film does not contain nickel as an element. The aluminum according to claim 7 or 8 , wherein boehmite is not precipitated in the surface treatment film. A container comprising at least a portion of aluminum having the surface treatment film according to claim 7 or 8 .

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