JP5633429B2 - Method of painting the workpiece - Google Patents

Description

  The present invention relates to a technique for coating an object to be processed on aluminum or an aluminum alloy, and more particularly to a method for coating an object to be processed that simplifies the pretreatment of the object to be processed which is a part made of aluminum or aluminum alloy.

  Conventionally, in an exterior aluminum part such as an outboard motor or an aluminum alloy part, an anodizing treatment is applied as a coating base to form a film in order to increase the rust prevention power of the outer surface of the part.

  The anodizing treatment is a treatment (alumite treatment) in which the surface of the object to be treated is oxidized by immersing the object to be treated in the treatment liquid as an anode and energized to form a film. Since the surface of this anodic oxide film is porous, the coating is generally carried out after previously sealing the surface of the oxide film.

  A general anodizing process is usually performed by batch processing including sealing treatment. The reason for applying batch processing is that anodization requires energization, so a special jig is required, and the anodized film is an unstable porous film, which is quickly sealed after film formation. This is because the hole needs to be closed by processing.

  The coating process after the sealing treatment is performed as a continuous line by changing the jig. In this case, dirt may be attached to the object to be processed by changing the jig. Therefore, it is essential to perform degreasing as a pre-coating process at the time of painting.

  In a conventional method of coating an object to be processed, the object to be processed is dried as a means for preventing the treatment liquid or water droplets from dripping from the object to be processed when changing jigs or moving between processes. ing.

  When drying a workpiece using a heater, heating equipment, process management, heat and other energy are required, but the corrosion of the workpiece is accelerated by heating, dry stains occur, There are problems such as extra time required for cooling.

  In addition, when drying by air blow, air equipment is required, water adhering to the object to be treated is scattered, corrosion proceeds due to insufficient drying, etc., or air is applied to the object to be treated. There are many problems in applying any of the drying means such as dust and dirt.

  For this reason, although it is desirable to omit a drying process, when a drying process is abbreviate | omitted, problems, such as a sealing treatment liquid (sealing bath) being brought into a degreasing bath other than the dripping of a water droplet, will arise. Generally, the sealing bath is acidic, and even if the washing is sufficiently performed, the shape of the object to be treated may be complicated, or the sealing bath may remain in the pores of the anodized film. There is a tendency that the sealing bath is brought into the basic degreasing bath and the deterioration of the degreasing bath is accelerated.

  In addition, if a sealing bath remains in the pores of the anodized film, the basic degreasing bath will be deteriorated faster, or the reactivity with the basic degreasing agent will increase and the anodized film will be attacked. It becomes easy. For this reason, it is necessary to remove moisture by drying in a conventional method of coating an object to be processed.

[Description of prior art]
FIG. 6 is a process diagram showing a method for coating an aluminum or aluminum alloy part (anodized part) on which an anodized film is formed by the prior art.

  As shown in FIG. 6, conventionally, anodization treatment (i) and sealing treatment (ii) using an energizing jig are performed on aluminum or an aluminum alloy as a first step (I).

  By this anodizing treatment (i) and sealing treatment (ii), the surface of the anodized film on the surface to be treated in aluminum or aluminum alloy parts is made flat without holes.

  After this sealing treatment (i), the surface to be treated is dried (D) and the jig is replaced.

  FIGS. 7A and 7B are schematic views for specifically explaining a conventional pre-painting treatment of an object to be treated.

  FIG. 7A is a cross-sectional view showing a state in which the anodized film 102 is formed on the aluminum base 101 using the energizing jig in the first step (I) shown in FIG. An anodized film 102 is formed on the surface of the aluminum substrate 101. A large number of porous holes 103 are formed on the surface portion of the anodized film 102.

  In FIG. 7B, sealing treatment (ii) is performed on the anodized film 102 that has been anodized (i) in the first step (I). In the sealing treatment (ii), the sealing bath (agent) 104 penetrates into the holes (103) of the anodized film 102, and the sealing agent 104 accumulates in the holes 103 and is sealed.

  After changing the jig, the degreasing step (iii) and the painting step (iv) are performed as a second step (II) by using a degreasing hanger and a painting hanger (not shown).

JP 2010-77532 A

  In the conventional painting technology of workpieces, drying of the workpieces after sealing treatment is performed to prevent dripping of treatment liquid and water droplets from the workpieces when changing jigs or moving between processes. Is doing.

  However, when drying an object to be processed with a heater, energy such as heating equipment for the object to be processed, process management, and heat is required.

  And when a to-be-processed object is heated, corrosion of a to-be-processed object will be accelerated | stimulated by heating, a dry stain will arise in a to-be-processed object, and cooling after drying will require time.

  Moreover, when drying a to-be-processed object by an air blow, an air installation is required, and there exists concern that water will scatter during this operation, or corrosion progresses due to insufficient drying.

  In addition, there are many problems with any drying, such as dust and dirt adhering to the object to be processed by air. For this reason, although it is desirable to omit a drying process, when a drying process is abbreviate | omitted, there exist problems, such as dripping of a water drop and a sealing bath being brought into a degreasing bath.

  Further, since the sealing bath is generally acidic, even if it is sufficiently washed with water, the shape of the object to be treated is complicated and the sealing bath remains in the pores of the anodized film. There is a possibility that the sealing bath is brought into the basic degreasing bath and the deterioration of the degreasing bath is accelerated.

  When the sealing bath (sealing agent) remains in the pores of the anodized film, the reactivity with the basic degreasing bath is increased, and the deterioration of the degreasing bath is accelerated and the anodized film is easily attacked. Therefore, in the conventional method, it is necessary to remove moisture by drying.

  The present invention has been made in consideration of the above-described circumstances. The anodized film of the object to be processed made of aluminum or aluminum alloy is sealed with a lithium ion-containing strong basic treatment bath, and sealed and degreased. It is an object of the present invention to provide a method for painting an object to be processed, in which the pre-painting treatment process is simplified.

  Another object of the present invention is to provide a method for coating an object to be processed which can perform a consistent process from the anodizing treatment to the coating process of an object to be processed made of aluminum or aluminum alloy, and does not require a drying process. is there.

The present invention has been made on the basis of the above-mentioned circumstances, and an anodized film is formed on an object to be processed made of aluminum or an aluminum alloy, and the object to be processed is coated with the anodized film as a base. In a method of coating an object, a first step including an anodizing treatment and a second step including a coating treatment are performed, and sealing treatment and degreasing treatment are integrated using a lithium ion-containing strong basic bath. Performing the anodizing process, sealing / degreasing process, and coating process by omitting the drying process between the first process including the anodizing process and the second process including the coating process It is characterized by that.

  In the method for coating an object to be treated according to the present invention, the anodizing treatment is not limited to a method using a specific anodizing bath. As electrolysis conditions, any of direct current, alternating current, and AC / DC superposition may be used, and the electrolysis conditions are not limited as long as a film is formed. The thickness of the anodized film is not particularly limited, but is preferably 3 μm or more and 40 μm or less.

  Moreover, in the coating method of the to-be-processed object of this invention, the lithium ion density | concentration of the sealing process liquid used for the sealing process which served as a degreasing | defatting shall be 0.02 g / L or more and 20 g / L or less, The said strong basicity It is desirable that the sealing treatment bath has a pH value of 10.5 or higher and a processing temperature of 10 ° C. or higher and 65 ° C. or lower.

  Furthermore, in the method for coating an object to be treated of the present invention, it is desirable to apply lithium hydroxide or lithium carbonate as the lithium ion source.

  In addition, in the method for coating an object to be treated according to the present invention, there are coating methods such as dipping, spraying, or roll coating as the coating treatment, and there are various types of paints such as urethane, epoxy, and acrylic, It is not limited to a specific coating method or using a paint.

  According to the method for coating an object to be processed according to the present invention, the anodized film of the object to be processed of aluminum or aluminum alloy is sealed with a strong basic bath containing lithium ions, and the sealing process and the degreasing process are integrated. Pre-coating treatment can be simplified, no degreasing component remains in the anodized film, and corrosion resistance and paint adhesion can be maintained well.

  Further, according to the method for coating an object to be processed according to the present invention, the drying process is omitted in the pre-treatment of the object to be processed of aluminum or aluminum alloy, thereby saving energy and space, and simplifying the pre-painting process. The number of steps can be reduced to improve production efficiency, and the quality of the formed film can be improved.

Process drawing which shows the coating method of a to-be-processed object. (A), (B) is sectional drawing which expands and shows the specific example of the sealing and the degreasing process shown in FIG. The figure which shows verification of the degreasing effect by a test example, and represents the adhesion test result of coating. Explanatory drawing which shows collectively the evaluation of the Example by the test piece of a to-be-processed object, and a comparative example. The figure which shows the adhesive test result of the Example and comparative example which were shown by FIG. Explanatory drawing which shows the process by a prior art. (A), (B) is sectional drawing for demonstrating the sealing process by a prior art.

  Embodiments of the present invention will be described below with reference to FIGS.

  FIG. 1 is a process diagram for explaining a method of coating an object to be processed according to an embodiment of the present invention.

  As shown in FIG. 1, in the coating method of the object to be processed, the anodizing process (S1), the sealing and degreasing process (S2), and the coating process (S3) are integrated as main processing steps of the object 1 to be processed. It is performed as a process.

  The workpiece is, for example, an exterior aluminum part of an outboard motor, and is aluminum or an aluminum alloy. In the anodizing step (S1) of the object to be processed, the surface of the object to be processed is oxidized by immersing the object to be processed in the anodizing solution as an anode and energizing using an energizing jig, so that the anodized film It is formed.

  The treatment liquid used in the anodizing step S1 may be either an acidic bath such as sulfuric acid, oxalic acid, or phosphoric acid, or a basic bath such as sodium hydroxide, sodium phosphate, or sodium fluoride. The coating method of the object to be processed according to the present embodiment is not limited to the one using a specific anodizing bath (treatment liquid).

  Further, the electrolytic conditions in the anodizing step S1 may be any of direct current, alternating current, and AC / DC superposition, and the electrolytic conditions are not limited as long as an oxide film is formed. In the anodizing step, a required current is applied to the substrate 2 made of aluminum or aluminum alloy, which is an object to be processed, to perform anodization, and an anodized film having a required thickness is formed on the aluminum substrate 2. The thickness of the anodizing treatment is not particularly limited, but an oxide film with a thickness of 3 to 40 μm is usually formed by controlling the energization time.

  After anodizing the aluminum substrate 2 in the anodizing step S1 to form an anodized film having a required thickness on the surface, the anodized film 3 of the workpiece 1 is sealed as shown in FIG. Is given. 2A shows the initial state of sealing in which the strongly basic sealing bath (sealing treatment liquid) 5 has permeated the anodic oxide film 3, and FIG. 2B shows the chemical reaction of the sealing bath 5 with chemical reaction. A state in which a pore is formed with Compound 6 is shown. The porous hole 4 of the anodic oxide film 3 is a compound 6 produced by a chemical reaction between the strong basic aqueous solution and the anodic oxide film 3 by the penetration of a strong basic sealing bath (strong basic aqueous solution) 5. Covering and basic sealing is performed.

  As shown in FIG. 2A, an anodized film 3 having a film thickness of 3 to 40 μm is formed on the surface of the aluminum base 2 in the anodizing step S1. The anodized film 3 is a porous hole, and a strong basic sealing bath (sealing treatment liquid) 5 containing lithium ions permeates into the hole 4 to perform the sealing process, thereby closing the hole 4. The lithium ion-containing strongly basic sealing bath 5 is an aqueous lithium hydroxide solution or an aqueous lithium carbonate solution, enters the pores of the anodized film 3 to form a compound in the pores 4 and is sealed.

  For the strongly basic sealing bath 5, the sealing treatment liquid described in JP 2010-77532 A is used, and the lithium ion concentration needs to be 0.02 to 20 g / L. The chemical reaction of the sealing treatment is promoted by lithium ions having a concentration of 0.02 g / L or more. The lower limit of the lithium ion concentration is 0.02 g / L, preferably 2 g / L. The upper limit is 20 g / L, preferably 10 g / L. A sealing treatment liquid having a lithium ion concentration exceeding 10 g / L is not preferable because a chemical reaction rapidly proceeds and dissolution of an aluminum base material (substrate) without an anodized film occurs.

  The pH value of the sealing treatment liquid needs to be 10.5 or more. Preferably it is 11 or more, more preferably 12 or more strong basicity is good. The upper limit of the pH value is 14 strongly basic. The sealing treatment liquid is preferably strongly basic, reacts easily with the anodic oxide film 3, and quickly forms the compound 6 in the pores, thus exhibiting high corrosion resistance. However, a weakly basic sealing solution having a pH value of less than 10.5 has a high corrosion rate and a low effect of improving corrosion resistance. Moreover, since pH value changes with lithium ion sources, pH value can be adjusted using bases, such as sodium hydroxide, sodium phosphate, sodium fluoride.

  The temperature of the sealing treatment liquid needs to be 10 ° C. or higher and 65 ° C. or lower. Preferably it is 25-50 degreeC. When the treatment is carried out at a temperature lower than 10 ° C., the activity is low and the reaction becomes weak, but a certain degree of corrosion resistance can be expected. On the other hand, when the temperature exceeds 65 ° C., dissolution of the film from the surface of the anodized film 3 proceeds, the film disappears, and high corrosion resistance cannot be obtained.

  In the present embodiment, a coating having excellent corrosion resistance can be formed on the anodized film 3 on the aluminum base 2 with a strong basic sealing bath (sealing treatment liquid) 5 in a short sealing process. At the same time, the strong basic sealing bath 5 has a degreasing effect of decomposing oil in the strong basic bath. In this sense, the strong basic sealing bath 5 is also configured to serve as a strong basic degreasing bath. By sealing the holes 4 of the anodized film 3 with the strong basic sealing bath 5, sealing is performed. Hole treatment and degreasing treatment can be performed simultaneously. Therefore, sealing and degreasing can be performed in a strong basic (treatment) bath containing lithium ions.

  The strongly basic sealing bath 5 containing lithium ions can decompose dirt such as oil and is different from a general sealing bath such as a nickel acetate salt sealing bath which is a commercially available sealing agent. And a degreasing effect can be obtained at the same time. Therefore, the manufacturing process which integrates a sealing process and a degreasing process can be constructed | assembled, and the strong basic (sealing) bath 5 containing lithium ion can perform sealing and a degreasing process simultaneously at once.

  As long as the treatment time (immersion time) of the strongly basic sealing bath (sealing treatment liquid) is at least 0.5 minutes, both the degreasing effect and the sealing effect can be obtained. High corrosion resistance is obtained. The upper limit of the treatment time is about 5 minutes, and if it exceeds 5 minutes, the dissolution of the anodic oxide film 3 proceeds, and the coating adhesion and corrosion resistance deteriorate.

  In this method of coating an object to be treated, a sealing treatment and a degreasing treatment (S2) are carried out by carrying out a sealing treatment of the anodized film 3 using a strong basic sealing bath (sealing treatment liquid) 5 containing lithium ions. ) Can be implemented simultaneously. Since the integration process of the sealing process and the degreasing process (S2) is possible, the degreasing process before painting performed independently becomes unnecessary.

  Moreover, since the sealing bath chemically reacts with the anodic oxide film to form the compound 6 by the sealing treatment using the strong basic sealing bath 5, the degreasing component does not remain and the drying step can be omitted. Omission of the drying process eliminates the need for heating equipment and air equipment. Therefore, energy saving and space saving can be achieved.

  The sealing process and the degreasing process of the holes 4 of the anodized film 3 can be integrated and performed at the same time, and since the drying process can be omitted, the pre-coating process can be simplified and the processing time can be shortened. Can do. Thereafter, in the coating step (S3), a coating treatment such as dipping, spraying, roll coating or the like can be performed using a urethane, epoxy, or acrylic paint. There are various types of coating methods for the object to be processed, and the method is not limited to a specific coating method or a method using a paint.

  In this method of coating an object to be treated, in the manufacturing process of an aluminum or aluminum alloy part in which an anodized film is applied to a coating base, the porous hole 4 of the anodized film is formed into a strong basic (sealed) bath containing lithium ions. By performing the sealing treatment in 5, the sealing and the degreasing treatment can be integrated and carried out simultaneously.

  Therefore, by performing the sealing process in the lithium ion-containing strong basic (sealing) bath 5, the sealing process and the degreasing process are performed simultaneously, and the drying process can be omitted, thus simplifying the pre-painting process. Is done. By integrating the sealing step and the degreasing step, a manufacturing process with a small number of manufacturing steps is possible. The components of the strongly basic (sealing) bath 5 enter the porous holes 4 of the anodized film 3 and chemically react with the anodized film to form the compound 6 on the holes 4 and the surface, so that the degreasing component is oxidized. It does not occur in the film.

  Further, when the anodized film 3 of the aluminum base 2 is sealed with a strong basic (sealing) bath 5 having lithium ions, no dripping occurs. Sealing treatment and degreasing treatment can be performed at the same time, and sealing can be performed on the painting line as a pretreatment for painting. Further, since the sealing treatment of the anodized film 3 can be performed with a hanger jig, the jig is replaced after the anodizing treatment, and the sealing treatment and the degreasing treatment are integrated so that drying before coating is performed. The process can be omitted.

[Action]
According to the method for coating an object to be processed according to this embodiment, the sealing process after the anodizing process of the object to be processed and the degreasing process before the coating are integrated, so that the manufacturing process is shortened and simplified. From anodizing to sealing and degreasing to painting, there is no need for a drying process, making the manufacturing process consistent, reducing the number of manufacturing processes and saving space, shortening the production line, and tact time Can be shortened.

  Moreover, since the drying process which existed between the 1st process including an anodizing process and the 2nd process including a coating process can be abolished by integration, a heating installation and an air installation become unnecessary, and energy saving and space saving can be achieved. Therefore, it is possible to prevent the occurrence of corrosion due to insufficient drying, the promotion of corrosion due to high temperature exposure, and the occurrence of dry stains.

  In general alkaline degreasing by conventional coating pretreatment, the degreasing agent may remain in the pores of the anodized film due to degreasing after sealing, thereby reducing coating adhesion. However, in this embodiment, in the lithium ion-containing strong basic (sealing) bath (treatment liquid), lithium ions chemically react with the anodized film to form compound 6, so there is no residual degreasing component, Decrease in paint adhesion can be prevented.

  In addition, there is a merit of simplification and simplification in process management of the manufacturing process. In the conventional manufacturing process, the acidic sealing liquid is brought into the alkaline degreasing bath, the pH value fluctuates, and the deterioration of the degreasing bath is accelerated. Further, since the anodic oxide film is formed of a porous material, the sealing liquid entering the holes cannot be sufficiently removed even by washing with water, and is often brought into a degreasing process.

  However, in the method for coating an object to be processed according to this embodiment, management items can be reduced by integrating sealing and degreasing. In the sealing treatment using the strongly basic (sealing) bath 5 containing lithium ions, the sealing bath chemically reacts with the anodic oxide film to produce the compound 6, so that the corrosion resistance of the anodic oxide film 3 is improved. Has an effect. A strongly basic bath used for general degreasing attacks the anodized film and dissolves to reduce the film thickness of the film or reduce the sealing effect. As a result, the corrosion resistance of the anodized film is reduced.

  In a strong basic (sealing) bath containing lithium ions, regardless of the strong basicity, the pores of the film can be closed without attacking the anodized film, and the corrosion resistance can be improved. In the coating method of the object to be treated according to the present embodiment, the sealing treatment and the degreasing treatment can be integrated and performed at the same time, and the component of the sealing bath is chemically reacted with the anodized film to produce the compound 6, and the degreasing component Does not remain on the film. Therefore, the attack of the anodic oxide film due to degreasing before coating can be eliminated, and a product with a stable quality can be provided.

[Experiment 1]
Next, as Experiment 1, the degreasing effect in the paint adhesion test of the test piece was verified.

  The exterior aluminum parts of outboard motors are anodized on the base of the paint to increase rust prevention. Since the anodic oxide film is porous, it is applied after sealing, but conventionally, a degreasing treatment has been performed as a pretreatment for this coating.

  In this embodiment, the sealing process is abolished, and after anodizing, the water is turned off and the jig is replaced. The test piece on which the anodized film was formed was degreased before painting using a strongly basic treatment bath of a lithium hydroxide aqueous solution, and then painted by spraying an acrylic paint. By using a strong basic treatment bath of lithium hydroxide solution for the degreasing treatment before painting, even if the degreasing treatment is omitted, the sealing treatment and the degreasing treatment can be performed simultaneously, and the manufacturing process can be shortened. .

  If a strong basic treatment bath is used, even if the sealing treatment is abolished, the bath can penetrate into the pores of the anodized film and dissolve oil, etc. A compound (solidified product) is generated by chemical reaction with the film and sealed. Therefore, the sealing treatment can be performed simultaneously by the degreasing treatment of the strongly basic treatment liquid, and the sealing step and the degreasing step before coating can be integrated. This is a coating method for an object to be processed equivalent to that shown in the present embodiment. This example corresponds to Test Example 4.

  In Test Examples 1 to 4, after an anodic oxidation film of about 10 μm was formed on each test piece by anodizing treatment, in the verification of the degreasing effect shown in FIG. After applying the oil, each treatment was performed, and the paint was coated to conduct an adhesion test. The adhesion of the coating in the adhesion test was evaluated by the foundation eye test method of JIS-K5400.

  In the verification of the degreasing effect, the case where degreasing is not performed is shown in the column of “No degreasing” in Test Example 1, and the case where the degreasing effect is confirmed by nickel acetate which is a commercially available sealing agent is “Nickel acetate” in Test Example 2. It is shown in the column.

  In addition, a case where the degreasing treatment was performed by applying “Kizai Mac Screen (NG-30)” which is a commercially available degreasing agent and immersed for about 3 minutes at 50 ° C., the column of “NG-30” in Test Example 3 It was shown to. Furthermore, the case where it processed using the strong basic processing liquid used by a present Example is shown in the column of "lithium" of Test Example 4, and the peeling test of the coating was done based on the said cross cut test method.

  In the adhesion test result, peeling was not caused in the degreasing treatment with “NG-30” in Test Example 3 and “lithium” in Test Example 4 (Example). It was found that in the test piece of the degreasing treatment of “Nickel acetate” in Test Example 2 and complete and significant peeling phenomenon occurred.

  As a result of the adhesion test, as shown in “Test Examples 1, 2, 3, and 4” in the upper column of FIG. 3, according to the test pieces of “Test Examples 3 and 4”, the coating does not peel off. It was suggested that sufficient quality products could be supplied. In Test Example 3, the adhesion was good, but the corrosion resistance was reduced. Test Example 4 corresponds to the example, and it was confirmed that the number of steps was small and the corrosion resistance and adhesion were excellent. The corrosion resistance of each test piece of “Test Examples 1, 2, 3, 4” was evaluated as shown in the lower column of FIG. 3, and Test Examples 2 and 4 were excellent. When the adhesion was evaluated, it was confirmed that the test piece of Test Example 4 corresponding to the Example was excellent.

[Experiment 2]
In Experiment 2, a paint adhesion test by a base eye test was performed on each test piece.

  As the test piece, an aluminum alloy die-cast material ADC12, which is an exterior aluminum part of an outboard motor, was used. The paint adhesion of this test piece was evaluated by the foundation eye test method of JIS-K5400.

  In the coating adhesion test, as shown in FIG. 4, Examples and Comparative Examples 1 to 4 were evaluated. FIG. 5 shows the results of the coating adhesion test of Examples and Comparative Examples 1 to 4.

[Example]
In the examples, a coating adhesion test by a cross-cut test is performed on the test piece treated in the present invention.

An aluminum alloy ADC12 was used as a test piece. This test piece was immersed as an anode in a 200 g / L sulfuric acid bath and energized for 20 minutes under the condition of a current density of 2 A / dm ² to form an anodic oxide film 3 having a thickness of 10 μm. And in order to evaluate the degreasing effect of the strongly basic sealing treatment bath 5 of the anodized film 3, the engine oil is evaluated on the evaluation surface (the anode of the test piece), assuming dirt adhered by changing the jig after the anodization. (Oxide film surface).

  Thereafter, the mixture was immersed in a strongly basic (sealing) bath containing 2 g / L of lithium ions and having a pH of 13 and a temperature of 25 ° C. for 1 minute to perform sealing and degreasing simultaneously. As for the painting, an acrylic paint made by Nippe Home Products Co., Ltd. was sprayed. The adhesion of the coating was evaluated by the cross-cut test method of JIS-K5400.

  According to the test piece of the above example, the number of manufacturing steps is as small as three steps of anodizing, sealing / degreasing, and coating, and as shown in FIG. It became possible to provide products.

[Comparative Example 1]
In Comparative Example 1, a coating adhesion test was performed on a test piece manufactured by the method shown in FIG.

  Similarly to the test piece of the example, engine oil was applied to the evaluation surface of the anodized film having a film thickness of 10 μm, and a commercially available sealing agent, nickel acetate salt sealing agent (Okuno Pharmaceutical's top seal H-298) was applied. A sealing treatment was performed by immersing at a temperature of 90 ° C. for 10 minutes.

  Then, it was dried for 20 minutes by a drying treatment, and after drying for 20 minutes, application of engine oil was performed because it was assumed that dirt adhered when the jig was replaced. Furthermore, after drying, degreasing was performed using a commercially available degreasing agent, and coating with an acrylic paint was applied to perform an adhesion test. A commercially available “Kizai Mac Screen NG-30” was used as the degreasing agent, and it was immersed at 50 ° C. for 3 minutes.

  As a result of the adhesion test, the coating did not peel off as shown in FIG. However, this test piece requires anodization, sealing, drying, degreasing and coating treatments for production, and there are many problems in the number of production steps.

[Comparative Example 2]
In Comparative Example 2, it was confirmed whether sealing and degreasing could be performed simultaneously using a commercially available sealing agent in the integrated process shown in the first embodiment (see FIG. 1). That is, similarly to the test piece of the example, an anodized film having a film thickness of 10 μm was formed, engine oil was applied to the evaluation surface of the anodized film, and the temperature was 90 ° C. using a commercially available nickel acetate salt sealing solution. Was soaked for 10 minutes to try sealing and degreasing simultaneously.

  After that, coating was performed by spraying acrylic paint, and an adhesion test was performed. As shown in FIG. 5, the test piece was almost peeled off, and the commercially available sealing agent had no degreasing effect and sufficient quality. It was found that could not be obtained.

[Comparative Example 3]
In Comparative Example 3, there was no effect of improving corrosion resistance, but in order to evaluate only the degreasing effect of the example, the degreasing effect by a commercially available degreasing agent was confirmed in the integrated process shown in FIG. Similar to the above example, engine oil was applied to an anodic oxide film with a thickness of 10 μm, degreased with a degreasing agent without sealing, and then painted with an acrylic paint to give paint adhesion. A test was conducted. A commercially available “Kizai Mac Screen NG-30” was used as the degreasing agent, and the test piece was immersed at 50 ° C. for 3 minutes.

  As a result of this coating adhesion test, as shown in FIG. 5, the coating of the test piece of Comparative Example 3 did not peel off, and the same result as the test piece of the example was obtained. It was confirmed that the test piece of Comparative Example 3 can obtain a sufficient degreasing effect. However, since the sealing treatment was not performed, the test piece had poor corrosion resistance.

[Comparative Example 4]
In Comparative Example 4, the coating adhesion when degreasing is omitted is evaluated in order to reduce the attack on the anodized film. Similar to the test piece of Comparative Example 3, after coating the engine oil on the anodized film having a thickness of 10 μm, the coating test was performed by directly spraying the acrylic paint without performing the sealing process or the degreasing process. As a result, all the coatings were peeled off (see FIG. 5).

[Effect of the embodiment]
According to the present embodiment, the anodized film of the object to be treated of aluminum or aluminum alloy is subjected to sealing treatment (or degreasing treatment) using a lithium ion-containing strong basic treatment bath, By integrating the degreasing treatment, the sealing and degreasing treatment can be performed at the same time, and the processing from the anodic oxidation of the workpiece to the sealing and degreasing and coating can be made consistent, and the treatment process is simplified.

  In addition, by integrating the sealing and degreasing treatment with a lithium ion-containing strong basic treatment bath, the drying treatment can be omitted, and it is not necessary to perform the degreasing treatment before painting alone. Energy saving and space saving can be achieved.

  Furthermore, the anodized film of the object to be treated is treated with a strongly basic treatment bath containing lithium ions, and the components of the bath are chemically reacted with the anodized film to produce a compound. Thickness reduction can be prevented, degreasing components do not remain in the film, and deterioration in paint adhesion can be prevented.

  Furthermore, the tact time can be shortened, thereby improving the production efficiency and improving the quality of the formed film without causing the occurrence of corrosion due to dry stains and insufficient drying. Can do.

1 Object (test piece)
2 Aluminum substrate 3 Anodized film 4 Hole 5 Strongly basic sealing bath (sealing solution)
6 Compound 101 Aluminum base material 102 Anodized film 103 Hole 104 Sealing treatment agent

Claims (5)

In the method of coating an object to be processed, an anodized film is formed on an object to be processed made of aluminum or an aluminum alloy, and the object to be processed is coated with the anodized film as a base.
A first step including an anodizing treatment and a second step including a coating treatment;
Using a strongly basic bath containing lithium ions, the sealing process and the degreasing process are integrated,
Between the first step including the anodizing treatment and the second step including the coating treatment, the drying step is omitted, and the anodizing treatment, the sealing / degreasing treatment, and the painting treatment are made into an integrated step. A characteristic method of painting an object to be treated. The said anodizing process is a coating method of the to-be-processed object of Claim 1 which sets the film thickness of an anodized film to 3 micrometers or more and 40 micrometers or less. The lithium ion concentration of the strongly basic bath used for the sealing and degreasing treatment is 0.02 g / L or more and 20 g / L or less,
The method for coating an object to be treated according to claim 1 or 2, wherein the pH value of the strongly basic bath is 10.5 or more and the treatment temperature is 10 ° C or more and 65 ° C or less. The method for coating an object to be treated according to claim 1, wherein lithium hydroxide or lithium carbonate is applied as the lithium ion source. As the coating process, dipping, applying the coating method of spraying or roll coating, as a paint, a urethane-based, epoxy-based, according to any one of claims 2 to 4 to apply paint Acrylic How to paint the workpiece.