JPS5853718B2 - How to treat anodized film - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for treating an anodic oxide film having high thermal conductivity, heat resistance, and electrical insulation.

Anodic oxide films of metals such as aluminum, magnesium, titanium, tantalum, and their alloys are metal oxide films chemically formed on the surfaces of these metals, and have a uniform structure, good adhesion to the underlying metal, and high thermal conductivity. It is a high electrical insulation film.

Recently, using the characteristics of this anodic oxide film, metal plates on which an anodized film has been formed have been used as printed wiring boards for electronic devices, ICs, etc.
, its use as a heat sink for LSI is being considered.

When using anodic oxide films for these applications, the film is made thick to improve insulation, but anodic oxide films with a thickness of several micrometers or more inevitably have many micropores. Occur.

These micropores are several hundred in diameter and reach the barrier layer of the anodic oxide film.

For this reason, in a thick anodic oxide film, a small amount of current flows due to moisture in the air or residual electrolyte during anodization, making it impossible to obtain sufficiently high insulation.

In order to improve this drawback, the micropores are sealed with steam or boiling water, but when the pore sealing treatment is performed, the oxide film deteriorates due to hydration, and even when heated to around 150°C, the anodization oxidizes. There is a problem that cracks occur in the film, resulting in a decrease in electrical insulation.

Another method is to form a resin film on the surface of the anodic oxide film to close the micropores, but although this method improves electrical insulation, it lowers thermal conductivity and causes problems such as problems with printed wiring boards and heat sinks as mentioned above. It is unsuitable when used as a

Furthermore, is there a method (Japanese Patent Publication No. 49-4719) in which an organic metal compound such as an organosilicon compound is deposited in the fine pores and on the surface of the oxide film by electric discharge using the anodic oxide film as an electrode in a gas? Since this method utilizes a discharge phenomenon, it is impossible to control the deposition site of the organometallic compound, which makes it difficult to sufficiently fill the micropores, and the organometallic compound is not deposited densely. , furthermore, there remains a bus through which current flows during discharge,
It has the disadvantage that its insulation properties tend to deteriorate due to the influence of moisture.

This invention was made in view of the above circumstances, and aims to provide a treatment method capable of forming an anodic oxide film having high thermal conductivity and electrical insulation. This method is characterized by attaching and depositing a polymerizable organometallic compound to the micropores (excluding anodized films formed on mu-silicon alloys) or the micropores and their surfaces, and then polymerizing them.

The present invention will be described in detail below.

The anodic oxide film used in this invention is aluminum,
It is obtained by subjecting anodic oxidizable metals such as titanium, tantalum, and magnesium and alloys of these metals (excluding aluminum-silicon alloys) to normal anodizing treatment.

This anodic oxide film is then treated with a polymerizable organometallic compound.

If necessary, pore sealing treatment may be performed in advance with steam, boiling water, or the like.

The polymerizable organometallic compound used here has polymerizability in which an organic group that can be hydrolyzed into a metal atom, a halogen group, and an organic functional group are bonded, and has the general formula %X: vinyl group, amino group , mercapto group, epoxy group,
Organic functional groups such as methyl and phenyl groups R: Hydrolyzable organic groups such as alkoxy and acetoxy groups, and organometallic compounds represented by n+m=3.4.5 or 6, such as phenyl. Triethoxysilane, methyltriethoxysilane, vinyltris(β-methoxyethoxy)silane, β-(3.4
-Organosilicon compounds such as -epoxy-cyclohexyl)ethyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, tetraisopropyl bis(dioctylphosphite) titanate, tetraoctylbis(ditridedylphosphite) titanate, titanium acetylacetate organic titanium compounds such as nitrate, titanium octylene glycolate, dihydroxybis(lactato)titanium, and tedrastearoxytitanium, organic aluminum compounds such as aluminum tri-n-butoxide, methylaluminum sesquichloride, and aluminum triisopropoxide, zirconium Organometallic compounds such as organic zirconium compounds such as n-butoxide, zirconium tetraisopropoxide, and tetra(n-butoxy)zirconium, as well as derivatives and low polymers (oligomers) of these compounds, are used, but methyl in the organic functional group is used. Those having a group and/or a phenyl group are preferable because they have a greater improvement in heat resistance.

Furthermore, it is better to use hydrolysis that occurs gradually.

These polymerizable organometallic compounds are used after being dissolved in an organic solvent such as methanol, ethanol, acetone, ethyl acetate, or methyl ethyl ketone, water, or a mixture of water and a water-soluble organic solvent.

As this water-soluble organic solvent, methanol, ethanol, isopropanol, acetone, dioxane, ethylene glycol, methyl acetate, methyl ethyl ketone, diacetone alcohol, ethyl formate, dimethyl formamide, etc. are used. Additives such as agents can be added.

Then, the anodic oxide film is immersed in such a polymerizable organometallic compound solution to diffuse and permeate the polymerizable organometallic compound into the micropores, or the solution is applied to the oxide film surface. This is carried out by forming a polymerizable organometallic compound layer or by using a vacuum impregnation method.

Alternatively, the oxide film is immersed in a solution in which a polymerizable organometallic compound is dissolved in water or a mixture of water and a water-soluble organic solvent, and a direct current is applied using the oxide film as an anode and a suitable inert conductor as a cathode. By applying electricity, the polymerizable organometallic compound can be sufficiently impregnated from the bottom of the micropores of the oxide film to the pore openings by electrophoresis, osmosis, etc.

At this time, since the polymerizable organometallic compound is a monomer, it can easily penetrate into the micropores, and it penetrates sufficiently to the deep part of the micropores.

When higher thermal conductivity is required for the resulting anodic oxide film, the polymerizable organometallic compound on the surface is not necessary, and it is sufficient that the micropores are sufficiently impregnated with the polymerizable organometallic compound. The polymerizable organometallic compound solution adhering to the surface of the oxide film can be completely wiped off by a wiping method, and when higher electrical insulation is required, the solution of the polymerizable organometallic compound on the surface of the oxide film can be removed not only in the micropores but also on the surface of the oxide film. Since it is desirable to also polymerize the oxide film, the polymerizable organometallic compound solution adhering to the surface of the oxide film is left as it is without being wiped off.

Once the polymerizable organometallic compound has been sufficiently attached and deposited on the surface or micropores of the anodic oxide film, the oxide film is dried and excess water and organic solvent are removed.

The polymerizable organometallic compound attached to or deposited on the surface or micropores of the anodic oxide film as described above is polymerized by a polymerization means such as heating.

Through this polymerization, the polymerizable organometallic compound becomes a dense organometallic compound polymer, and since these organometallic compounds have a high affinity with the oxide film, the surface of the oxide film,
It firmly adheres to the inside of the pore, filling the inside of the fine pore tightly or covering the surface.

In the anodic oxide film treated with the polymerizable organometallic compound as described above, the micropores are virtually filled with the organometallic compound polymer, or the film surface is also coated with the polymer, resulting in extremely high electrical insulation. You can get sex.

Furthermore, since only the micropores can be filled with the polymer, electrical insulation is improved while maintaining high thermal conductivity.

Furthermore, electrical insulation properties at high temperatures (approximately 150° C.) are also improved.

In addition, since the filled and coated polymer is metal-based, the polymer itself has excellent thermal conductivity, and the oxide film covering the surface has a higher thermal conductivity than the conventional oxide film coated with resin. have sex.

Hereinafter, this invention will be specifically explained based on Examples.

Example 1 A 30 μm thick aluminum anodic oxide film was formed on a 100 mm x 50 ill EX Iin 28 aluminum plate in a 15% sulfuric acid aqueous solution, and C was applied to the surface of this oxide film.
A 3020% ethanol solution of H2-CH8i (OC2H40CH3) was applied, dried at room temperature, and then heated at 130°C for 2 hours to polymerize, forming an organometallic compound polymer film with a thickness of about 10 μm.

When the dielectric strength voltage was measured by placing a mercury droplet with a diameter of 5 μ on this polymer film as one electrode and using the base aluminum as the other electrode, a dielectric strength voltage of IK■ or higher was obtained.

Further, this sample was left indoors for one week and the dielectric strength was measured after that, and no deterioration in electrical insulation properties due to the influence of humidity was observed.

Example 2 An aluminum anodic oxide film with a thickness of 30 μm was formed in the same manner as in Example 1, and the oxide film was used as an anode in a 4% aqueous solution of CH2=CH81(QC2H,0CH3)3, and the initial voltage was 250 V and the final voltage was 400 V.
After applying a direct current of V, 25rrLA for 2 hours, the oxide film was taken out from the aqueous solution, the aqueous solution adhering to the surface was thoroughly wiped off, and then dried with warm air, and then heated at 130°C.
Polymerization was carried out by heating for 2 hours.

When the dielectric strength voltage of this sample was measured in the same manner as in Example 1, a withstand voltage of 800V was obtained.

Even after being left indoors for one week, no deterioration in performance was observed.

Furthermore, when the cross section of this sample was analyzed using an X-ray microanalyzer, it was confirmed that the organometallic compound polymer was impregnated to the deepest part of the micropores of the cured film, as shown in FIG.

Note that in FIG. 1, line I and line 1 of AI indicate the distribution of Si.

Example 3 An aluminum plate on which an anodized film was formed in the same manner as in Example 1 was treated with methyltriethoxysilane CH3S i (0
C2H5) 330 vol1%, ethanol 60vol
In a solution of 10vo■% water, using an aluminum plate as an anode, initial voltage 400V, final voltage 500V, 25mA/d.
DC current was applied for 1 hour at m.m.

Take out the aluminum plate from the solution and dry it with warm air,
Polymerization was carried out by heating at 130°C for 2 hours.

After performing an activation treatment on this sample, electroless nickel plating was performed and the AC dielectric strength voltage was measured, and a withstand voltage of IK■ or higher was obtained.

Further, the pressure resistance after being left indoors for one week was also higher than IKV, and no influence of humidity was observed.

When a cross section of this sample was subjected to line analysis using an X-ray microanalyzer, it was confirmed that the organometallic compound was impregnated to the deepest part of the micropores of the oxide film.

Example 4 An aluminum plate on which a 30μ thick anodic oxide film was formed in the same manner as in Example 1 was coated with titanium octylene glycol root (C4Hg O) 2T i (C8H1602) 2
Vacuum impregnation was carried out in a solution of 60% by volume and 40% by volume of Improper Tool, and the above-mentioned organometallic compound solution was impregnated into the micropores.

Thereafter, the aluminum plate was taken out from the solution, the liquid adhering to the surface was wiped off, it was dried with warm air, and it was heated at 100° C. for 2 hours to perform a polymerization treatment.

Next, when we measured the AC dielectric strength voltage of this sample, it was found to be 80
A breakdown voltage of 0V or more was obtained.

Example 5 In Example 4, CH3 was used as the polymerizable organometallic compound.
A similar treatment was performed using A 1 (C4H90) 2, and the AC dielectric strength voltage of the treated sample was measured in the same manner as in Example 1, and a withstand voltage of 700 V or more was obtained.

Example 6 In the same manner as in Example 2, a sample was prepared in which the micropores of the anodic oxide film were impregnated with an organometallic compound polymer.

This sample was activated by immersing it in an aqueous solution of palladium chloride 0.59773 at room temperature for 10 minutes, and then electroless nickel plating was performed at a temperature of 90° C., and then an electric circuit was formed.

After plating, it was washed with water, the water adhering to the surface was wiped off, and the AC insulation voltage between the electric circuit and the base aluminum was measured, and a voltage resistance of 800 V or more was obtained.

In addition, the pressure resistance was reduced after being left indoors for one week (no change was observed).

Example 7 An aluminum plate on which a 30μ thick anodic oxide film was formed in the same manner as in Example 1 was heated to CH2-CH8i (OC2H4
It was immersed in a 20vol 1% ethanol solution of 0CH3)3 and left for 1 hour to allow the solution to diffuse and permeate into the micropores.

After removing the solution from the anodized film and wiping off the solution adhering to the surface, it was heated at 150° C. for 2 hours to polymerize.

The AC dielectric strength voltage of this sample was 500V or more.

Example 8 100x50x1mm magnesium alloy plate (JISI
seeds) to acidic ammonium fluoride 300? /l, sodium dichromate 1009/1. , phosphoric acid (85%) 90m
In an aqueous solution containing J/l, the bath temperature is 75°C and the current density is 5A/l.
d77L'' for 50 minutes to a thickness of approximately 30 mm.
An anodic oxide film of μm was obtained.

This film was then treated with 85 v methyltriethoxysilane.
DC IKV, 1577LA using the film as an anode in a solution of 1% ethanol, 5vol% ethanol, and 10vol% water.
The sample was energized for 1 hour.

Next, the magnesium alloy plate was heated at 150° C. for 2 hours to polymerize the polymerizable organometallic compound.

The AC dielectric strength voltage of this sample was 700V or more.

Example 9 17wt 2S aluminum plate of 100X50X1
% oxalic acid aqueous solution, bath temperature 20℃, current density 2A/dm"
An anodic oxidation treatment was performed to form a 30 μm anodic oxide film.

Next, zirconium tetraisopropoxide was vacuum impregnated into the fine pores of this film, left in the air for 24 hours to perform hydrolysis, and then heated at 130° C. for 2 hours to polymerize.

When we measured the AC dielectric strength voltage of this sample, we found that it was 5.
It was 00v or more.

As explained above, the method for treating an anodic oxide film of the present invention is a method for treating anodic oxide film (excluding an anodic oxide film formed on an aluminum-silicon alloy). Since the organic metal compound is attached, deposited, and then polymerized, the treated anodic oxide film obtained by this process has high thermal conductivity, heat resistance, and electrical insulation properties, and is suitable for printed wiring boards of electronic devices and heat dissipation. In addition to being able to be effectively used for plates, etc., it is also possible to freely adjust the parts on which the polymerizable organometallic compound is attached and deposited, so electrical insulation and thermal conductivity can be varied, making it possible to create anodes with various characteristics. An oxide film can be easily obtained.

Furthermore, it has advantages such as a simple processing method, simplified equipment, and low processing cost.

[Brief explanation of the drawing]

The drawing is a measurement chart when a cross section of the anodic oxide film treated according to the present invention was subjected to line analysis using an X-ray microanalyzer, where the ■ line shows the distribution of A1 and the ■ line shows the distribution of Si.

Claims (1)

[Scope of Claims] 1. Micropores or micropores and the surface of the anodic oxide film (excluding anodized film formed on aluminum-silicon alloys) are formed by the general formula (wherein M: 5i1Ti, AI, Zr X: vinyl group, amino group, mercapto group, epoxy group,
Organic functional groups such as methyl groups and phenyl groups R: hydrolyzable organic groups such as alkoxy groups and acetoxy groups, and halogen groups (n+m=3.4.5 or 6) A polymerizable organometallic compound is attached. A method for treating an anodic oxide film, which comprises impregnating the film with a polymerizable organometallic compound, and then polymerizing the polymerizable organometallic compound. 2. A patent characterized in that the polymerizable organometallic compound is adhered to and impregnated into the micropores or the micropores and the surface of the anodic oxide film using electrochemical means, and then the polymerizable organometallic compound is polymerized. A method for treating an anodic oxide film according to claim 1. 3. A polymerizable organometallic compound is attached to and impregnated into the micropores or micropores and the surface of the anodic oxide film by electrochemical means using a solution in which the polymerizable organometallic compound is dissolved in water. A method for treating an anodic oxide film according to claim 2. 4. The polymerizable organometallic compound is applied to the micropores or the micropores and the surface of the anodic oxide film by electrochemical means using a solution in which the polymerizable organometallic compound is dissolved in a mixture of water and a water-soluble organic solvent. 3. The method for treating an anodic oxide film according to claim 2, which comprises impregnating the anodic oxide film with a compound.