JP4667775B2 - Resin-coated aluminum material - Google Patents

Description

  The present invention relates to a resin-coated aluminum material, and more particularly, to a resin-coated aluminum material excellent in grounding properties, electromagnetic wave shielding properties, corrosion resistance, resin layer adhesion, and moldability.

2. Description of the Related Art Conventionally, an aluminum material that has been preliminarily molded into a predetermined shape and then subjected to a ground treatment and a coating treatment has been used as a housing that houses an electronic device or the like. In recent years, in order to reduce costs, it has become the mainstream to perform a forming process after performing a coating process first.
By the way, with respect to the case of a magnetic recording device such as a hard disk, in order to prevent malfunction of the computer, grounding to prevent static electricity from accumulating in the case and electromagnetic wave shield to shield electromagnetic waves generated from the inside of the case Sex has come to be demanded. Since the coating applied to coat the casing is generally insulating and does not show electromagnetic shielding properties, metal particles (Ni, Cu, Ag, Co, Zn, Cr, Fe, etc.) are contained in the coating. Or by adding metal soap to the coating film to impart conductivity to the coating film and impart electromagnetic shielding properties. Patent Document 1 discloses an aluminum plate material in which conductive powder and metal soap are added to a resin layer, although the applications are different.
JP-A-5-320685

However, as in Patent Document 1, if metal particles or metal soap is added to the coating film, the adhesion of the coating film may be reduced. In particular, in the recent manufacturing process of housings that are molded after coating, there are many cases where the molding process is performed in a complicated shape without applying lubricating oil, and thus there is a problem that the coating film peels off after the molding process. there were.
Further, from the viewpoint of recent environmental protection, the use of chromate treatment, which has been used conventionally as a base treatment for coating films, is decreasing, and the use of alumite sulfate treatment as an alternative has increased. However, since alumite sulfate is a porous film, corrosive substances may enter and corrode aluminum. In addition, the sulfate alumite film contains several tens of percent of sulfate ions, and the sulfate ions may react with the coating film and metal particles to further reduce the adhesion of the coating film.

  The present invention has been made in view of the above circumstances, and provides a resin-coated aluminum material that is excellent in corrosion resistance, moldability, and adhesion of a metal particle-containing resin layer, and also excellent in grounding properties and electromagnetic wave shielding properties. For the purpose.

In order to achieve the above object, the present invention employs the following configuration.
The resin-coated aluminum material of the present invention includes a metal substrate made of aluminum or an aluminum alloy, and the metal substrate having a thickness of 10 nm to 300 nm, a porosity of 3% or less, and an anion content of 5% or less. And a thickness containing metal particles composed of one or more of Ni, Cu, Ag, Co, Zn, Cr, and Fe applied on the anodized film. Is composed of a resin layer having a thickness of 10 μm or less, and the metal particle-containing resin layer is made of polyester resin, epoxy resin, alkyd resin, acrylic resin, urethane resin, or two or more main component resins. while it is contained in an amount of 0.1 wt% to 10 wt%, in which the surfactant is to be contained in a range of 0.1% to 10% by weight this The features.

According to said structure, the adhesiveness of a metal particle containing resin layer can be improved by using the anodic oxide film as a base film. In particular, since the anion content of the anodized film is 5% or less, the reaction between the anion contained in the anodized film and the main component resin or metal particles contained in the metal particle-containing resin layer is suppressed. The adhesion of the particle-containing resin layer can be improved.
Furthermore, when the porosity of the anodic oxide film is 3% or less, a non-porous anodic oxide film is obtained, and the barrier property against the corrosive substance is increased, thereby improving the corrosion resistance. In addition, the adhesion and moldability are improved as the corrosion resistance is improved.
In addition, the metal particle-containing resin layer contains metal particles composed of one or more of Ni, Cu, Ag, Co, Zn, Cr, and Fe. Can be made. In addition, by incorporating a surfactant into the metal particle-containing resin layer, lubricity is imparted to the resin layer, and even when the aluminum material is molded after the resin layer is formed, slipping between the molding die and the resin layer is possible. As a result, the moldability can be improved while preventing peeling of the resin layer.

  The resin-coated aluminum material of the present invention is the resin-coated aluminum material described above, wherein a silane coupling agent is applied between the anodized film and the metal particle-containing resin layer. And

  By interposing a silane coupling agent between the anodized film and the metal particle-containing resin layer, the adhesion strength between the anodized film and the metal particle-containing resin layer is dramatically increased. In particular, the silane coupling agent can be applied to the surface of the anodic oxide film of the metal base before forming or applied to the anodic oxide film of the metal base that has already been processed to apply or dry the adhesive. Without performing, the adhesion strength of the metal particle-containing resin layer can be improved.

According to the resin-coated aluminum material of the present invention, the resin layer is excellent in corrosion resistance, moldability, and adhesion of the metal particle-containing resin layer, and the resin layer is one of Ni, Cu, Ag, Co, Zn, Cr, and Fe. Or since the metal particle which consists of 2 or more types is contained, the resin-coated aluminum material which was excellent also in grounding property and electromagnetic wave shielding property can be provided.

  As shown in FIG. 1, the resin-coated aluminum material A of the present embodiment is applied onto a metal substrate 1, an anodized film 2 formed on the surface 1 a of the metal substrate 1, and the anodized film 2. And a metal particle-containing resin layer 3. Further, the metal particle-containing resin layer 3 (hereinafter sometimes referred to as the resin layer 3) is formed from a main component resin 3a, metal particles 3b dispersed in the main component resin 3a, and a surfactant. Has been. In FIG. 1, the anodic oxide film 2 and the resin layer 3 are laminated only on the upper surface of the metal substrate 1, but the anodic oxide film 2 and the resin layer 3 may be laminated on the entire surface of the metal substrate 1. Of course it is good.

The metal substrate 1 is made of aluminum or an aluminum alloy. The aluminum or aluminum alloy is not particularly limited, and is pure aluminum-based 1000 series alloy, Al-Cu series, Al-Cu-Mg series 2000 series alloy, Al-Mn series 3000 series alloy, Al-Si series. 4000 series alloy, Al-Mg series 5000 series alloy, Al-Mg-Si series 6000 series alloy, Al-Zn-Mg-Cu series, Al-Zn-Mg series 7000 series alloy, Al-Fe-Mn series 8000 series alloys are used, and casting alloys such as forming alloys, structural alloys, electrical alloys, AC1A, AC2A, AC3A, and AC4B are used.
Also, those alloys subjected to various tempering treatments such as solution treatment and aging treatment can be used. Further, a clad material obtained by cladding these aluminum alloys on the surface can also be used. Moreover, the thing of the processed material which gave press molding processing etc. previously may be sufficient, and an unprocessed board | plate material, an extrusion material, and a cast may be sufficient.

  Next, the anodic oxide film 2 is formed by electrolytically treating the surface 1a of the metal substrate 1 as will be described later, and has a thickness of 10 nm to 300 nm and a porosity of 3% or less. The anion content is 5% or less. The anodic oxide film 2 can improve the corrosion resistance of the metal substrate 1 by covering the surface 1 a of the metal substrate 1. Further, the anodic oxide film 2 can improve the adhesion of the metal particle-containing resin layer 3 by being chemically bonded to the main component resin 3 a included in the metal particle-containing resin layer 3. If the film thickness of the anodic oxide film 2 is less than 10 nm, the film thickness tends to be non-uniform and the adhesion to the metal substrate 1 and the corrosion resistance are lowered, which is not preferable. On the other hand, if the film thickness exceeds 300 nm, cracks occur in the anodized film 2 itself when the resin-coated aluminum material A is formed into a predetermined shape, and the adhesion of the anodized film 2 to the metal substrate 1 and the metal base Since the corrosion resistance of the material 1 falls, it is not preferable. In addition, a decrease in the adhesion of the anodic oxide film 2 is not preferable because it induces the peeling of the resin layer 3 during the molding process, lowers the lubricity with the molding die and lowers the moldability. A particularly desirable film thickness of the anodic oxide film 2 is in the range of 50 nm to 200 nm.

  The porosity of the anodic oxide film 2 is preferably 3% or less. When the porosity exceeds 3%, the amount of anions contained in the anodic oxide film 2 increases, and this anion reacts with the main component resin 3a or the metal particles 3b contained in the resin layer 3 to cause adhesion of the resin layer 3. This is not preferable. Further, a decrease in the adhesion of the resin layer 3 is not preferable because it induces the peeling of the resin layer 3 during the molding process, lowers the lubricity with the molding die and lowers the moldability. Further, when the porosity exceeds 3%, a large number of holes are formed, which is not preferable because the barrier property of the anodic oxide film 2 is lowered and the corrosion resistance of the metal substrate 1 is lowered. A more preferable porosity range is 1% or less.

  The anodized film 2 may contain anions in the course of the electrolytic treatment, but the anion content in the anodized film 2 is preferably 5% or less. When the anion content exceeds 5%, the anion reacts with the main component resin 3a or the metal particles 3b of the metal particle-containing resin layer, and the adhesion of the metal particle-containing resin layer 3 is lowered. This is not preferable because peeling of the resin layer 3 is induced, the lubricity with the molding die is lowered, and the moldability is lowered. A more preferable range of the anion content is 3% or less.

Next, the metal particle-containing resin layer 3 is configured by adding metal particles 3b and a surfactant to the main component resin 3a.
As the main component resin 3a, one or two or more resins among polyester resins, epoxy resins, alkyd resins, acrylic resins, and urethane resins are preferable. These main component resins 3 a have a functional group having a relatively high activity such as a carbonyl group. The functional group forms a chemical bond with the anodic oxide film 2, thereby anodizing. The adhesion between the film 2 and the metal particle-containing resin layer 3 can be improved.

  Moreover, as the metal particle 3b, the particle | grains which consist of 1 type, or 2 or more types in Ni, Cu, Ag, Co, Zn, Cr, Fe, etc. are preferable. By adding these metal particles 3b, conductivity is imparted to the resin layer 3, and the resin-coated aluminum material A can exhibit grounding properties and electromagnetic wave shielding properties.

  Moreover, the content rate of the metal particle 3b with respect to the metal particle containing resin layer 3 has the preferable range of 0.1 to 15 mass%. If the content of the metal particles 3b is less than 0.1% by mass, grounding properties and electromagnetic wave shielding properties are hardly obtained, which is not preferable. If the content exceeds 15% by mass, the adhesiveness of the resin layer 3 decreases. This is not preferable. A more preferable content of the metal particles 3b is in a range of 1% by mass to 10% by mass.

The average particle diameter of the metal particles 3b is preferably in the range of 0.01 μm to 7 μm. If the average particle size is less than 0.01 μm, the dispersibility in the resin is lowered and the grounding property is lowered, which is not preferable. Moreover, since it will become easy to peel from a coating film when an average particle diameter exceeds 7 micrometers, it is unpreferable.
The film thickness of the metal particle-containing resin layer 3 is preferably in the range of 10 μm or less. When the film thickness exceeds 10 μm, a crack is generated in the resin layer 3 itself when the resin-coated aluminum material A is molded into a predetermined shape, and the adhesion of the resin layer 3 and the corrosion resistance of the aluminum material A are reduced. Absent. A more preferable film thickness of the resin layer 3 is in a range of 1 μm to 6 μm.

Next, the surfactant imparts lubricity to the metal particle-containing resin layer 3, improves the slipping property between the molding die and the resin layer 3 during molding, prevents the resin layer 3 from peeling off, and moldability. To improve. Moreover, use of the lubricating oil at the time of shaping | molding can be abbreviate | omitted, and a shaping | molding process can be simplified more.
Examples of the surfactant added to the resin layer 3 include nonionic compounds such as alkylphenol ethylene oxide adducts and higher alcohol ethylene oxide adducts, higher alcohol sulfates, alkylbenzene sulfonates, and higher alcohol phosphates. Any one or two or more of cationic systems such as anionic, higher alkylamine salts, alkyltrimethylammonium salts, and sapamine type quaternary ammonium salts are preferable. The content of the surfactant with respect to the resin layer 3 is preferably in the range of 0.1% by mass to 10% by mass. When the content of the surfactant is less than 0.1% by mass, it is not preferable because the lubricity cannot be imparted to the resin layer 3. When the content exceeds 10% by mass, the adhesion of the resin layer 3 is not preferable. Is unfavorable because it decreases. The more preferable content rate of surfactant is the range of 1 mass% or more and 5 mass% or less.

If necessary, a silane coupling agent may be applied between the anodic oxide film 2 and the metal particle-containing resin layer 3. The silane coupling agent generates a chemical bond between the anodic oxide film 2 and the main component resin 3a or the metal particles 3b of the metal particle-containing resin layer 3, and adheres the anodic oxide film 2 to the metal particle-containing resin layer 3. Improve sex more. As the silane coupling agent, amino-based, epoxy-based, vinyl-based, methacrylic-based, mercapto-based and the like are preferable, and more specifically, 3- (triethoxysilyl) propylamine, N-β-aminoethyl- Examples thereof include γ-aminopropyltrimethoxysilane.
The coating amount of the silane coupling agent to the anodic oxide film 2 is preferably 1 mg / ^{m 2} or more 200 mg / ^{m 2} or less. If the coating amount is out of this range, the adhesion of the metal particle-containing resin layer 3 is lowered, which is not preferable.

Next, the manufacturing method of the resin-coated aluminum material A of this embodiment will be described.
First, the metal base material 1 which consists of said aluminum or aluminum alloy is prepared. The metal substrate 1 is preferably pretreated in advance. The means for this pretreatment is not particularly limited as long as it can remove the oil and fat adhering to the surface 1a of the metal substrate 1 and remove the heterogeneous oxide film on the surface. For example, after performing a degreasing treatment with a weak alkaline degreasing solution, after performing alkali etching with a sodium hydroxide aqueous solution, a method of performing a desmut treatment in a nitric acid aqueous solution or a method of performing acid cleaning after a degreasing treatment is appropriately selected. Used.

  Next, the surface 1a of the metal substrate 1 is electrolytically treated in an electrolytic bath to form the anodic oxide film 2. In the electrolytic bath, boric acid, borate, phosphate, adipate, phthalate, benzoate, which are electrolytes that are difficult to dissolve the generated anodic oxide film and produce a nonporous film, An aqueous solution in which one or more selected from the group such as tartrate and citrate is dissolved is used. Of these electrolytes, boric acid, adipate, and phthalate are preferable from the viewpoints of properties of the oxide film, cost, and the like. The electrolyte concentration in the electrolytic bath is selected in the range of 2% by mass to the saturated concentration of the electrolyte. For example, in the case of boric acid, a range of 2% to 5% is preferable. If the electrolyte concentration is too high, the film solubility may be increased to form a porous film, and the anion content may be increased. The bath temperature of the electrolytic bath is sufficient in the range of 20 to 40 ° C., and it is not necessary to set the bath temperature to a high temperature of 40 ° C. or higher. The pH of the electrolytic bath is preferably in the range of pH 6.0 to 8.0. If the pH is too high, it tends to be porous, which is not preferable.

In this electrolytic bath, the metal substrate 1 is electrolyzed by being connected to a power source so as to be an anode even if it is continuous or intermittent. An insoluble conductive material is used for the cathode. As the electrolytic current, a direct current is used. In direct current electrolysis, electrolysis is performed with a direct current density of about 3 to 5 A / dm ² and an electrolysis time of about several seconds to 10 minutes. If the current density is low, electrolysis for a long time is required, resulting in an increase in cost, and the film is more likely to be dissolved, so that there is a possibility of becoming porous. The applied voltage is in the range of about 5 to 220 V, preferably about 35 to 145 V, because there is a relation that the thickness of the oxide film formed with respect to a voltage of 1 V is about 14 mm in direct current. From the viewpoint of a power supply device or the like, it is preferably 220 V or less, and excellent adhesion and corrosion resistance can be obtained even by electrolysis at such a low voltage. By this electrolysis, a uniform anodic oxide film 2 having a thickness of 10 to 300 nm, preferably 50 to 200 nm, is formed on the surface 1 a of the metal substrate 1.

  The anodic oxide film 2 thus obtained is almost nonporous, and its porosity is 3% or less at maximum. Further, the anion content of the anodic oxide film 2 is 5% by mass or less, usually 1 to 3% by mass, which is a very low value.

  The above anodic oxidation treatment can be performed on unprocessed aluminum or aluminum alloy, and can also be performed on a state after a forming process such as a press process.

Next, a metal particle-containing resin layer 3 is applied on the formed anodic oxide film 2. The resin layer 3 is applied by preparing a paint in which the main component resin 3a, the metal particles 3b, and the surfactant are dispersed in an appropriate solvent, and applying the paint to the anodic oxide film 2 using a bar coater or the like. After coating with a bar coater or the like, the solvent is removed by heating or the like, whereby the metal particle-containing resin layer 3 is obtained.
In this way, a resin-coated aluminum material A composed of the metal substrate 1, the anodic oxide film 2, and the metal particle-containing resin layer 3 is obtained.

  A silane coupling agent may be applied on the anodic oxide film 2 before forming the metal particle-containing resin layer 3. The silane coupling agent is applied by preparing a paint obtained by diluting the silane coupling agent with an appropriate solvent, and applying the paint to the anodic oxide film 2 using a bar coater or the like. After coating with a bar coater or the like, the silane coupling agent is applied by removing the solvent by heating or the like. The coating amount of the silane coupling agent may be adjusted by the dilution concentration of the coating material and the coating amount of the coating material by a bar coater or the like.

According to the resin-coated aluminum material A, since the anion content of the anodic oxide film 2 as a base film is 5% or less, the anion contained in the anodic oxide film 2 and the main component contained in the metal particle-containing resin layer 3 are included. The reaction with the resin 3a or the metal particles 3b is suppressed, whereby the adhesion of the resin layer 3 can be improved.
Further, by setting the porosity of the anodic oxide film 2 to 3% or less, it becomes a non-porous anodic oxide film, and the barrier property against the corrosive substance is increased and the corrosion resistance can be improved. Furthermore, with this improvement in corrosion resistance, the adhesion of the resin layer 3 and the moldability of the aluminum material A itself can be improved.
Moreover, since the metal particle 3b is contained in the resin layer 3, the grounding property and electromagnetic wave shielding property of the resin-coated aluminum material A can be improved. Further, when the resin layer 3 contains a surfactant, lubricity is imparted to the resin layer 3, and even when the aluminum material A is molded after the resin layer 3 is formed, the molding die and the resin layer are formed. 3 can be improved, and the resin layer 3 can be prevented from peeling off and the moldability can be improved.

  As described above, according to the resin-coated aluminum material A, the adhesion between the anodic oxide film 2 and the metal particle-containing resin layer 3 can be improved, and the corrosion resistance against corrosive substances can be improved. Further, the grounding property and the electromagnetic wave shielding property can be improved.

Hereinafter, the present invention will be described in more detail by Experimental Examples 1 and 2.
(Experimental example 1)
First, an aluminum alloy plate material of JIS A5052 rolled to 1.0 mm was prepared as a metal substrate. This plate was etched with a 10% NaOH aqueous solution at 50 ° C. for 30 seconds, and then washed with water for 30 seconds. Subsequently, the plate was washed with a 10% HNO ₃ solution for 30 seconds and then washed with water for 30 seconds. Next, in an aqueous boric acid solution having a pH of 3, a liquid temperature of 60 ° C., and a concentration of 10%, an electrolytic treatment was performed at 1.5 A / dm ² using the metal substrate as an anode and carbon as a cathode to form an anodized film. . The film thickness of the nonporous anodic oxide film was adjusted by voltage, and the electrolysis time was 30 seconds.

  Next, a main component resin made of a polyester resin having an average molecular weight of 8000, metal particles made of nickel powder having an average particle size of 0.1 μm, and a surfactant made of a higher alcohol ethylene oxide adduct are dispersed in isopropyl alcohol. A paint was prepared. The coating material was applied on the anodized film and then baked at 180 ° C. for 60 seconds to form a metal particle-containing resin layer. In addition, the content rate of the metal particle in a metal particle containing resin layer was 3 mass%, the content rate of surfactant was 1 mass%, and the thickness of the metal particle containing resin layer was 3 micrometers.

For some samples, a silane coupling agent was applied on the anodized film before forming the metal particle-containing resin layer. Specifically, a 1% aqueous solution of 3- (triethoxysilyl) propylamine (amino-based silane coupling agent) was prepared, and this aqueous solution was applied onto the anodic oxide film with a bar coater for 3 minutes at 100 ° C. A silane coupling agent was applied by performing a heat treatment. The coating amount was 30 mg / m ² .

As described above, the resin-coated aluminum materials of Examples 1 to 5 and Comparative Examples 1 to 11 were manufactured. Table 1 shows details of examples and comparative examples.
In Comparative Examples 4 and 5, an alumite sulfate film having a thickness of 1.0 μm was formed in place of the nonporous anodic oxide film. Further, for Comparative Examples 6 and 7, a chromate film having an adhesion amount of 20 mg / m ² was formed in place of the nonporous anodic oxide film. Moreover, about the comparative example 8, the content rate of the metal particle was 0.04 mass%. Further, in Comparative Example 9, the content of metal particles was 16% by mass. In Comparative Example 10, the surfactant content was 0.04 mass%, and in Comparative Example 11, the surfactant was 11 mass%.

In addition, the porosity of the resin layer in Table 1 is obtained by taking an enlarged photo of 100,000 times with an electron microscope at any 20 locations on the surface of the anodized film, and measuring the aperture area ratio of the holes with respect to the imaged area. The opening area ratio was defined as the porosity. In addition, the measurement object was a hole having an opening area of 5 nm ² or more and a depth of 5 nm or more. Moreover, the special site | part which the intermetallic compound etc. existed and the film | membrane has become discontinuous was excluded from the measurement.
The thickness of the resin layer in Table 1 was determined by cutting the anodized film with a microtome and observing the cross section.
Furthermore, the anion content of the resin layer in Table 1 was determined by analyzing in the depth direction of the anodized film by SIMS (secondary ion mass spectrometer).

About the aluminum material of the obtained Example and the comparative example, electromagnetic wave shielding property and earthing property, the moldability of an aluminum material, the adhesiveness of a metal particle containing resin layer, and corrosion resistance were investigated. The results are shown in Table 1.
The electromagnetic wave shielding property and grounding property depend on the conductivity of the resin layer. Therefore, the resin layer was peeled off from the metal substrate, and the conductivity of the resin layer alone was measured. From the results, the electromagnetic shielding properties and the grounding properties were evaluated. The case where the resistance value was 100Ω or less was rated as ◯, and the case where the resistance value exceeded 100Ω was rated as ×.

  The formability was evaluated by placing an aluminum material between the punch and the die and performing cylindrical deep drawing. Processing was performed under the conditions that the punch diameter was 30 mm, the die diameter was 31.8 mm, and the molding speed was 20 mm / second. A sample having a breaking height of 5 mm or more was evaluated as ◯, and a sample having a breaking height of less than 5 mm was evaluated as ×.

  Adhesion is when a 1/4 inch steel ball is dropped from a height of 50 cm on an aluminum material, and is peeled off after applying an adhesive tape to the resin layer on the convex surface. The degree of peeling of the resin layer was evaluated. The case where the resin layer was not peeled was rated as “◯”, the case where the ratio of the peeled area to the area of the deformed portion was 5% or less, and the case where the ratio exceeded 5% was marked as “X”.

  Corrosion resistance was evaluated by carrying out a DuPont impact test in the same manner as described above, spraying 5% saline solution continuously on the aluminum material after the test for 30 days, and then observing the corrosion state of the surface. No change in appearance, ◯, no more than 10 spot-like corrosion parts with a diameter of 2 mm or less, △, corrosion exceeding 2 mm in diameter, or more than 10 spot-like corrosions with a diameter of 2 mm or less What was seen was set as x.

  As shown in Table 1, good evaluation results were obtained for Examples 1 to 5.

In Comparative Example 1, since the porosity of the anodic oxide film was large, the barrier property was lowered and the corrosion resistance was deteriorated. Along with this, the adhesion of the metal particle-containing resin layer was lowered, and the moldability of the aluminum material itself was also lowered.
In Comparative Example 2, since the anion content of the anodic oxide film was large, the adhesion of the resin layer was lowered, thereby reducing the corrosion resistance and moldability.
In Comparative Example 3, since the thickness of the anodic oxide film was too thick, the anodic oxide film cracked and the corrosion resistance deteriorated. Along with this, the adhesiveness and moldability of the resin layer decreased.

In Comparative Examples 4 to 7, since the base film was an alumite sulfate film or a chromate film, the adhesion, corrosion resistance, and moldability of the resin layer were not sufficient.
In Comparative Example 8, the moldability, adhesion, and corrosion resistance were good, but the grounding properties and electromagnetic wave shielding properties were greatly reduced because the metal particle content was not sufficient.

About Comparative Example 9, since the content rate of the metal particles was too high, the adhesiveness of the resin layer was significantly lowered, and the moldability and corrosion resistance were lowered accordingly.
In Comparative Example 10, the content of the surfactant was insufficient and the grounding property and the electromagnetic wave shielding property were deteriorated. Moreover, about Comparative Example 11, since there was too much content rate of surfactant, a moldability, adhesiveness, and corrosion resistance fell.

(Experimental example 2)
In the same manner as in Experimental Example 1, an aluminum alloy plate material of JIS A5052 rolled to 1.0 mm was prepared as a metal substrate. The plate material was subjected to an electrolytic treatment in the same manner as in Experimental Example 1 to form an anodic oxide film having a porosity of 1%, an anion content of 3%, and a thickness of 100 nm.

  Next, paints were prepared by dispersing main component resins, metal particles, and surfactants of various materials in isopropyl alcohol. The coating material was applied on the anodized film and then baked at 180 ° C. for 60 seconds to form a metal particle-containing resin layer. Details of the metal particle-containing resin layer are shown in Table 2.

As described above, the resin-coated aluminum materials of Examples 6 to 11 and Comparative Examples 12 to 14 were manufactured. Table 2 shows details of Examples and Comparative Examples.
About the aluminum material of the obtained Example and the comparative example, it carried out similarly to Experimental example 1, and investigated the earth property, electromagnetic wave shielding property, moldability, the adhesiveness of a resin layer, and corrosion resistance. The results are shown in Table 2.

  As shown in Table 2, good evaluation results were obtained for Examples 6 to 11.

  It is suitably used as an aluminum material for a housing such as a hard disk.

The cross-sectional schematic diagram of the heat resistant aluminum material which is embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Metal base material, 1a ... Surface, 2 ... Anodized film, 3 ... Metal particle containing resin layer, 3a ... Main component resin, 3b ... Metal particle, A ... Resin coating aluminum material

Claims (2)

A metal substrate made of aluminum or an aluminum alloy, and an anodic oxide film formed on the surface of the metal substrate having a thickness of 10 nm to 300 nm, a porosity of 3% or less, and an anion content of 5% or less And a resin layer having a thickness of 10 μm or less containing metal particles made of one or more of Ni, Cu, Ag, Co, Zn, Cr, and Fe applied on the anodic oxide film. The metal particle-containing resin layer is composed of one or more main component resins of polyester resin, epoxy resin, alkyd resin, acrylic resin, and urethane resin, and 0.1 to 10 mass % of metal particles. % while being contained in a range of resin-coated surfactant is characterized in that comprising been contained in a range of 0.1 wt% to 10 wt% aluminum Wood.   The resin-coated aluminum material according to claim 1, wherein a silane coupling agent is applied between the anodic oxide film and the metal particle-containing resin layer.

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