JP2003313684A - Aluminum sheet for electronic equipment and molded article for electronic equipment using the sheet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an aluminum sheet for electronic equipment, which is superior in fingerprint resistance and scratch resistance as well as in electroconductivity, heat-radiating characteristics and formability, and to provide a molded article using it. <P>SOLUTION: The aluminum sheet 1 has a corrosion resistant film 3 and a resin film 4 sequentially formed from an aluminum base sheet 2 side on at least one side of the base sheet 2 having an arithmetical mean roughness Ra of 0.2-0.6 μm, wherein the corrosion resistant film 3 contains Cr or Zr and has a coating weight of 10-50 mg/m<SP>2</SP>in Cr or Zr terms; the resin film 4 has an average film thickness of 0.05-0.3 μm, and contains a lubricant of 1-25 mass% with respect to a total resin-coating amount; and the surface of the aluminum base sheet 2 or the corrosion resistant film 3 formed thereon, has such fine projections exposed outside the surface of the resin coating 4 that a surface resistance value between a spherical terminal with a radius of 10 mm and the aluminum base sheet 2 is 1 Ω or less, when the surface on the resin coating 4 side is pressed with the spherical terminal at a load of 0.4 N. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an aluminum plate for electronic equipment and a molded article for electronic equipment using the same.
In particular, it has excellent conductivity, heat dissipation, moldability, fingerprint resistance and scratch resistance, and is used for various external recording device cases and chassis, liquid crystal panel back covers, fixing frames, electronic equipment casings, or structural members. The present invention relates to an aluminum plate for electronic equipment, which is suitable as a material for the above, and a molded article for electronic equipment using the same.

[0002]

2. Description of the Related Art Conventionally, personal computers (hereinafter,
An electronic computer such as a “personal computer” is provided with an external recording device (hereinafter referred to as “drive device”) for storing data. As a typical example of this drive device, for example, a hard disk drive (Hard Disk Drive, which enables high speed and large capacity)
Hereinafter, referred to as "HDD", an optical disk drive (for example, CD-ROM, CD-R, etc.) capable of increasing the capacity of a recording medium for storing data, removable or portable.
CD-RW, DVD-ROM, DVD-RAM, DVD
-What is called RW, etc.) or the above HDD
And a magneto-optical disk drive (so-called MO, MD) which has the characteristics of an optical disk drive, and a flexible disk drive which has a relatively large recording medium capacity and is relatively easy to use. (Flexible Disk Drive, or Z
ip) and the like.

In a so-called desktop type personal computer which is placed on a desk or the like, a CRT (Cathode Ray Tub) is used as a display.
e: cathode ray tube), and the drive device is usually integrated with the CRT, or the CRT is used.
It is installed near the and used. Therefore, the CRT
And electromagnetic noise generated from various electronic devices installed in the vicinity of the CRT easily causes a problem when data is written or reproduced by the drive device, and in some cases causes a serious malfunction. was there. Incidentally, recently, the drive device has come to be mounted also on a so-called notebook type personal computer (hereinafter referred to as “notebook personal computer”) which is lightweight and easy to carry, and electronic circuits around the drive device and the like. Due to the electromagnetic noise generated from the above, the same problem as described above is likely to occur.

Therefore, in order to suppress such malfunctions as much as possible and enhance the reliability of the drive device, for example, the drive device is grounded to prevent intrusion of electromagnetic noise and inflow of minute current into the interior of the drive device. Measures such as prevention are taken. The method of grounding the drive unit is to connect a ground wire directly to the case or chassis of the drive unit, or to use a member having excellent conductivity (for example, copper or brass) on the surface of the case or chassis of the drive unit. , A metal leaf spring made of stainless steel (SUS) or the like, a method of contacting a sponge with a metal mesh wound gasket), a method of attaching a conductive tape, or the like has been put into practical use. Therefore, the drive device case and chassis are required to have conductivity necessary for grounding (grounding).

Recently, a liquid crystal display which consumes low power, is lightweight, and is easy to carry has attracted attention in various fields of commercial and consumer electronic devices. Examples of such a liquid crystal display include a liquid crystal display mounted on the notebook computer. This liquid crystal display generally includes a liquid crystal panel as an image display device, a back cover for protecting the liquid crystal panel, and a liquid crystal panel fixing jig (hereinafter, referred to as “fixing frame”) for fixing the liquid crystal panel to the back cover. However, similarly to the case of the drive device, the back cover and the fixing frame are required to have conductivity for removing static electricity that causes image noise.

Further, the heat generated in the electronic device may break the wiring inside the electronic device or cause the performance deterioration of various electronic parts provided in the electronic device. Therefore, the electronic device material is required to have a heat dissipation property for efficiently releasing the heat generated in the electronic device to the outside.

[0007] In addition, the above-mentioned material for electronic devices should have a formability capable of being relatively easily formed into a desired shape, or should have a good appearance when the electronic device is transported or installed. It is required to have fingerprint resistance, scratch resistance, etc. that can be easily handled. Therefore, in order to satisfy these various characteristics required for the materials for electronic devices, stainless steel (S
Various metal materials such as US), steel materials, and aluminum materials are applied to the electronic device materials. In addition, recently, there is a tendency that aluminum materials, which are relatively lightweight among metal materials, such as notebook computers, are used more and more.

However, when an aluminum material is used as a material for electronic equipment, it is difficult to satisfy the above various characteristics by itself, so various surface treatment methods have been proposed in order to improve the characteristics. . For example, JP-A-4
In JP-A-330683, by coating an aluminum plate with a resin containing a lubricant, fingerprints adhering to the surface and fine scratches generated on the surface are made inconspicuous.
A surface-treated aluminum plate having excellent fingerprint resistance and scratch resistance has been proposed.

According to this method, although the fingerprint resistance and the scratch resistance of the aluminum plate are improved to some extent, the surface of the aluminum plate coated with the resin as the insulating material exhibits the insulating property. When grounding from the housing or structural member of the equipment, a post-process such as scraping off a part of the resin film to provide a conductive part exposing the metal of aluminum is necessary to ensure grounding. .

Therefore, as means for solving the problem of ensuring conductivity on the surface of such an aluminum plate, JP-A-7-313930 and JP-A-7-31 are cited.
A technique for coating a resin containing a conductive substance is proposed in Japanese Patent No. 4601 or the like.

[0011]

However, in the method of coating the surface of an aluminum plate with a resin containing a conductive substance, it is necessary to uniformly disperse particles of the conductive substance in the resin. Therefore, when the contact between the particles of the conductive substance is not sufficiently ensured in the resin film formed on the surface of the aluminum plate, there arises a problem that desired conductivity cannot be obtained. Therefore,
In order to obtain the desired conductivity, it was necessary to increase the amount of the conductive substance added.

However, when a large amount of the conductive substance is added to the resin, the resin film becomes hard and brittle, and therefore, when the aluminum plate having the resin film formed thereon is pressed, the resin film is formed. There is a problem that cracking (peeling) is likely to occur.

The present invention has been made in view of the above problems, and an object thereof is a case and chassis of a drive device, a frame for fixing a liquid crystal panel, a housing of electronic equipment such as a rear cover, and these. In addition to improving the electrical conductivity and heat dissipation required for the structural members, excellent moldability that cracks (peeling) of the resin film can be suppressed even when press molding is performed, and the appearance is poor due to fingerprints or scratches. It is an object of the present invention to provide an aluminum plate for electronic devices, which is excellent in fingerprint resistance and scratch resistance, and which is capable of significantly reducing the above, and a molded product using the same.

[0014]

[Means for Solving the Problems] The present invention has the following constitution to achieve the above object. That is, the present invention is an aluminum plate in which a corrosion resistant coating and a resin coating are sequentially formed from the base plate side on at least one surface of an aluminum base plate having a center line average roughness Ra of 0.2 to 0.6 μm. The corrosion resistant coating contains Cr or Zr, and the adhesion amount is 10 to 50 m in terms of Cr or Zr conversion value.
g / m ² , and the resin film has an average film thickness of 0.05.
.About.0.3 .mu.m and 1 to 25 with respect to the total amount of resin film
The aluminum base plate containing a mass% of lubricant, or the surface on which the corrosion resistant film is formed, the fine projections are exposed on the surface of the resin film, and the resin film is formed. An aluminum plate for electronic equipment having a surface resistance value of 1Ω or less between the spherical terminal and the aluminum base plate when a spherical terminal having a tip portion with a radius of 10 mm is pressed against the side surface with a load of 0.4N. (Claim 1).

According to this structure, the center line average roughness Ra of the aluminum base plate and the average film thicknesses of the corrosion resistant coating and the resin coating are regulated within the respective predetermined ranges. The fine protrusions of the base material or the corrosion resistant film are exposed on the surface of the resin film, and the desired conductivity and heat dissipation are secured, and at the same time, the moldability, fingerprint resistance and scratch resistance are improved. The aluminum plate for electronic equipment is realized.

Further, it is desirable that the resin film is composed of at least one selected from polyester resins, urethane resins, epoxy resins, and vinyl resins (claim 2). According to this structure, when the aluminum plate for electronic equipment is subjected to molding, the resin film easily follows the deformation of the aluminum base plate.
An aluminum plate for electronic devices, which is much more excellent in moldability, is realized.

The lubricant is composed of at least one selected from polyethylene wax, polyalkylene wax, microcrystalline wax, fluorine wax, lanolin wax, carnauba wax, paraffin wax and graphite. Is desirable. According to this structure, appropriate lubricity can be imparted to the surface of the aluminum plate for electronic devices, and thus the aluminum plate for electronic devices with improved moldability can be realized.

Further, it is desirable that the resin film contains 1 to 30% by mass of colloidal silica based on the total amount of the resin film (claim 4). According to this structure, since colloidal silica having a relatively high hardness is added to the resin film, the resin film can be further hardened to improve scratch resistance, and as a result, the scratch resistance can be improved. An aluminum plate for electronic equipment having improved properties is realized.

Further, the present invention is configured as a molded article for electronic equipment molded by using the aluminum plate for electronic equipment. According to this structure, a molded article for electronic equipment, which is excellent in conductivity, heat dissipation, moldability, fingerprint resistance, and scratch resistance, is realized.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below. FIG. 1 is a sectional view schematically showing the configuration of an aluminum plate for electronic equipment according to the present invention.
As shown in FIG. 1, an aluminum plate 1 for an electronic device according to the present invention has a surface roughness (center line average roughness Ra) adjusted on a surface of an aluminum base plate 2 adjusted within a range regulated by the present invention. A resin film 4 containing a lubricant is coated with a corrosion resistant film 3 for ensuring sufficient corrosion resistance.
Are formed. Hereinafter, the reason for limiting the numerical values of the respective elements constituting the aluminum plate 1 for an electronic device according to the present invention will be described.

[Aluminum Base Plate] The aluminum base plate 2 used in the present invention is not particularly limited, and may be made of aluminum or an aluminum alloy having various components, tempers and plate thicknesses, if necessary. it can.

(Centerline average roughness R of the aluminum base plate)
a: 0.2 to 0.6 μm) The center line average roughness Ra of the aluminum base plate included in the present invention is the same as the above-mentioned average film thickness of the corrosion resistant coating and the resin coating, and the conductivity and molding of the aluminum plate for electronic devices. It is an important parameter that contributes to the development of various properties such as resistance, fingerprint resistance, scratch resistance, and heat dissipation.

That is, when the center line average roughness Ra of the aluminum base plate is less than 0.2 μm, the glossiness of the surface of the aluminum plate for electronic equipment becomes excessively high, and the fingerprints and the surface adhered to the surface can be obtained. The fine scratches generated on the surface become more noticeable, and the fingerprint resistance and scratch resistance are inferior. Further, in this case, the base material of the aluminum base plate having the fine irregularities, or the convex portions of the corrosion-resistant coating formed along the fine irregularities on the base material are less likely to be exposed on the surface of the resin coating. Therefore, it becomes difficult to secure desired conductivity and heat dissipation.

On the other hand, when the center line average roughness Ra of the aluminum base plate exceeds 0.6 μm, cracks are likely to occur in the aluminum base plate when the aluminum base plate is bent. A streak pattern may become conspicuous in the resin film in the bent portion, or the resin film may be easily peeled off. Therefore, in the present invention, the center line average roughness Ra of the aluminum base plate is
By controlling the thickness in the range of 0.2 to 0.6 μm, the electroconductivity, moldability, fingerprint resistance, scratch resistance, heat radiation property, etc. are enhanced, and an aluminum plate for electronic devices is obtained.

As a method of adjusting the center line average roughness Ra of the aluminum base plate within the range regulated by the present invention, for example, the surface roughness is appropriately set in the rolling process of the aluminum base plate. Examples thereof include a method of performing finish rolling using a rolling roll, and a method of performing etching treatment on the surface of the aluminum base plate after rolling under appropriate conditions.

In the present invention, the corrosion resistant coating and the resin coating are sequentially formed on the aluminum base plate on which the center line average roughness Ra is adjusted and fine irregularities are thus formed. And by setting the film thickness of the resin film to a predetermined film thickness regulated by the present invention, the fine protrusions of the base material of the aluminum base plate or the corrosion resistant film are exposed on the surface of the resin film, It is possible to obtain an aluminum plate for electronic devices, in which the electrical conductivity and the heat dissipation are ensured and the moldability, fingerprint resistance and scratch resistance are improved.

[Corrosion-Resistant Coating] The corrosion-resistant coating included in the present invention is provided to impart the required corrosion resistance to the aluminum base plate. In the present invention, as the corrosion resistant coating, a conventionally known corrosion resistant coating containing Cr or Zr as a main component, which is a phosphoric acid chromate coating, a chromate chromate coating, a zirconium phosphate coating, a coating type chromate coating, or a coating type zirconium coating. Etc. can be used appropriately. In the present invention, the above-mentioned Cr or Z
Since the attached amount of r (Cr or Zr conversion value) can be measured relatively easily and quantitatively using, for example, a conventionally known fluorescent X-ray method, it can be used for the electronic device without impairing the productivity. It is possible to control the quality of aluminum plates.

(Amount of corrosion resistant film deposited: 10 to 50 mg /
m ² ) When the adhesion amount of the corrosion resistant coating included in the present invention is less than 10 mg / m ^{2 in} terms of Cr or Zr conversion, the entire surface of the aluminum base plate cannot be uniformly coated,
It becomes difficult to secure corrosion resistance, and the aluminum plate for electronic devices cannot be used for a long time. Note that Cr or Zr, which is the main component of this corrosion resistant coating, is a metallic element, and if these metallic elements are exposed on the surface of the resin coating included in the present invention, the aluminum plate for electronic devices according to the present invention It is possible to further improve the conductivity and heat dissipation of the.

^{On the other hand} , if it exceeds 50 mg / m ² , conductivity and heat dissipation are secured, but in press molding or the like, the corrosion-resistant film itself is cracked (peeled), and high corrosion resistance can be maintained for a long period of time. The problem of becoming difficult arises. Therefore, in the present invention, the adhesion amount of the corrosion-resistant coating is 10 to 50 mg / in terms of Cr or Zr conversion value.
Restrict within the range of m ² .

[Resin Coating] The resin coating included in the present invention is provided to impart desired fingerprint resistance and scratch resistance to the aluminum plate for electronic devices. Further, in the present invention, the average film thickness of the resin film is regulated within a predetermined range in order to develop desired fingerprint resistance and scratch resistance.

(Average film thickness of resin film: 0.05 to 0.3)
μm) That is, the average film thickness of the resin film is 0.05 μm
When it is less than m, the fingerprint resistance and the scratch resistance are poor, and the lubricity is insufficient, so that the molding process becomes difficult. And
When the average film thickness of the resin film exceeds 0.3 μm, even if the surface roughness of the aluminum base plate is rough, the resin film covers almost all of the base material of the aluminum base plate or the corrosion resistant film, resulting in an extremely high surface resistance value. It becomes extremely high and the conductivity cannot be properly secured. Further, in this case, the generated heat is accumulated in the resin film, and the heat dissipation cannot be properly secured. Therefore, in the present invention, the average film thickness of the resin film,
It is regulated within the range of 0.05 to 0.3 μm.

From the standpoint of formability, it is desirable that the resin film is a resin that relatively easily follows the deformation of the aluminum base plate, such as polyester resin, urethane resin,
More preferably, it is composed of at least one selected from an epoxy resin and a vinyl resin.

Although the present invention is not particularly limited to the method for forming the resin coating, for example, from the viewpoint of productivity, the resin in liquid form is continuously formed on the coiled aluminum base plate on which the corrosion resistant coating is formed. It is desirable to use a roll coating method that can be applied. In this case, the liquid resin applied by the roll coater is baked when passing through the inside of the continuous oven to form a resin film.

At this time, since the resin coating is initially in a liquid state when applied on the corrosion resistant coating, first, the recesses on the surface of the corrosion resistant coating reflecting the surface roughness of the aluminum base plate are given priority. The film is filled with the powder and then baked to form a harder film.

Further, in the present invention, the respective performances of fingerprint resistance and scratch resistance, the average film thickness of the resin film, the surface roughness (center line average roughness Ra) and the corrosion resistance of the aluminum base plate are previously set. The relationship between each parameter of the film adhesion amount (Cr or Zr conversion value) is obtained, and based on these relationships, the above parameters are appropriately set so that desired fingerprint resistance and scratch resistance can be obtained. can do. Further, in the present invention, the average film thickness of the resin film can be relatively easily obtained from the area of the portion where the resin film is formed and the amount of the resin.

(Content of Lubricant Based on Total Resin Coating: 1 to 25% by Mass) The lubricant contained in the present invention improves the formability of the aluminum plate for electronic equipment. When the amount of the lubricant is less than 1% by mass with respect to the total amount of the resin film, sufficient lubricity cannot be obtained, and when the press working is applied, a part of the molded product is locally deformed. , It may cause the resin film to be narrowed or cracked (peeled).

When the amount of the lubricant exceeds 25% by mass with respect to the total amount of the resin film, the effect of improving the lubricity is saturated, while the film forming property of the resin film is deteriorated and the scratch resistance is deteriorated. Of the aluminum film for electronic devices, which may cause deterioration of the product temperature, or the resin film exfoliation (dust) that has been partially peeled off during press processing may accumulate inside the die for press processing. Will be adversely affected. Therefore, in the present invention, the content of the lubricant is regulated to 1 to 25 mass% with respect to the total amount of the resin film.

As the lubricant, polyethylene wax, polyalkylene wax, microcrystalline wax, fluorine wax, lanolin wax, carnauba wax, from the viewpoint of appropriately matching the improvement of moldability and economy. It is desirable to be composed of at least one selected from paraffin wax and graphite. In the present invention, a polyalkylene oxide wax can be used as the polyalkylene wax, and a polytetrafluoroethylene wax can be used as the fluorine wax.

(Exposure of the base material of the aluminum base plate or the projections of the corrosion-resistant coating to the surface of the resin coating) In the aluminum plate for electronic equipment according to the present invention, when the aluminum plate is applied to the member of the electronic equipment, the aluminum base and the ground are connected. In order to properly secure the conductivity at the contact point, it is necessary to expose the base of the aluminum base plate having the fine irregularities or the convex portion of the corrosion resistant coating included in the present invention to the surface of the resin coating. Then, the degree (dispersion degree) of exposing the fine projections of the base material or the corrosion resistant coating of the aluminum base plate to the surface of the resin coating is basically the center line average roughness Ra of the aluminum base plate, This is performed by appropriately adjusting the relationship with the average film thickness of the resin film.

(Surface resistance value: 1 Ω or less) Furthermore, in the aluminum plate for electronic equipment according to the present invention, it is necessary that the surface resistance value measured by the method described below is 1 Ω or less. That is, when the aluminum plate for electronic equipment having a surface resistance value of more than 1 Ω is applied to electronic equipment,
It becomes difficult to completely remove noise caused by electromagnetic waves and the like. Particularly, when the electronic device is a drive device, a writing or reproducing error is easily induced,
If the electronic device is a liquid crystal display, image noise is likely to occur. Therefore, in the present invention, the surface resistance value is regulated to 1 Ω or less.

In the present invention, in order to reduce the surface resistance value to 1Ω or less, the center line average roughness Ra of the aluminum base plate regulated by the present invention is within the range (0.2 to 0.6 μm) and the resin film is formed. Within the average film thickness (0.05-0.3 μm)
Then, the center line average roughness Ra of the aluminum base plate and the average film thickness of the resin film may be appropriately adjusted. Furthermore, in the aluminum plate for electronic devices according to the present invention, the resin film is formed on the aluminum base plate having the center line average roughness Ra with appropriate uniformity, whereby the fineness of the aluminum base plate is improved. The protrusions of the corrosion-resistant coating formed along the irregularities are exposed on the surface of the resin coating to a desired degree (dispersion degree), and the surface resistance value of 1 Ω or less at the desired portion of this surface. You will get it.

As parameters that greatly contribute to the surface resistance value, in addition to the center line average roughness Ra of the aluminum base plate and the average film thickness of the resin film, the type of resin, the type and amount of lubricant are used. Etc. Therefore, it is difficult to specify the present invention only by the correlation between the center line average roughness Ra of the aluminum base plate and the average film thickness of the resin film. Therefore, the present invention is specified by including the limiting condition "the aluminum plate having a surface resistance value of 1 Ω or less" as described above.

The surface resistance value for specifying the aluminum plate for electronic equipment according to the present invention can be measured by the following method. FIG. 2 is a diagram schematically showing an example of the method for measuring the surface resistance value. This surface resistance measurement method uses sandpaper or the like on one of the terminals of the tester 11 on the back surface or the end surface of the aluminum plate 10 for electronic equipment in which the corrosion resistant film and the resin film are formed on the surface of the aluminum base plate. Connect to the part where the corrosion resistant film and resin film have been removed by polishing, and tester 1
The other end of 1 is connected to the measurement location of the resin coating of the aluminum plate 10 for electronic equipment through a metal measuring rod 12 having a spherical terminal with a tip portion formed in a substantially spherical shape with a radius of 10 mm. It can be carried out. The metal measuring rod 12 may be made of brass or the like having excellent conductivity.

Then, the spherical terminal provided at the tip of the metal rod 12 is pressed against the measurement point of the resin film of the aluminum plate 10 for electronic equipment with a load of 0.4 N (40 gf), and in this state, The surface resistance value of the aluminum plate 10 for electronic devices is measured. Since the natural oxide film on the surface of the metallic measuring rod 12 causes variations in the measured surface resistance value, the surface of the metallic measuring rod 12 is previously sanded before the measurement of the surface resistance value. It is desirable that the natural oxide film be sufficiently removed by polishing with paper or the like.

Further, in the present invention, when the analog type tester 11 is used at the time of measuring the surface resistance value, in order to eliminate the influence of the internal resistance of the tester 11, before measuring the surface resistance value, It is desirable to perform the zero point correction in a state where the measuring portion formed of a spherical terminal provided at the tip of the metal measuring rod 12 and the opposite electrode are in contact with each other. In the present invention, in such measurement of the surface resistance value, the most sensitive range of the analog type tester 11 is used, and when the display needle of this tester 11 is stopped, the value pointed to by this display needle is Measured value. When a digital tester is used in the present invention, the zero point is corrected in the same manner as the analog tester 11 before measuring the surface resistance value, and the most sensitive range of this tester is used. And measure. Then, the value when the digital display of this digital tester is stable is taken as the measured value.

In the present invention, in order to sufficiently secure the reliability of the measured value of the surface resistance, the surface resistance value is measured at least at 10 random positions on each aluminum plate 10 for electronic equipment. It is desirable to use the average value as the surface resistance value regulated by the present invention.

On an aluminum base plate having a surface roughness within the range controlled by the present invention, a corrosion resistant film having an adhesion amount within the range controlled by the present invention and a resin film having a film thickness within the range controlled by the present invention were formed. At this time, the surface resistance value can be lowered by configuring the base material of the aluminum base plate which is a conductor or the corrosion resistant coating so as to be appropriately exposed on the surface of the resin coating. At this time, if the surface resistance value is 1 Ω or less, when a ground wire is provided on the aluminum plate on which the corrosion resistant coating and the resin coating are sequentially formed on the aluminum base plate, it is appropriate to use a contact point between the ground wire and the aluminum plate. It is possible to obtain an aluminum plate for electronic equipment, in which conductivity is ensured.

However, the surface roughness of the aluminum base plate, that is, its center line average roughness Ra is smaller than the range regulated by the present invention, and the average film thickness of the resin film is thicker than the range regulated by the present invention. In the case, that is, under the condition that the resin film is configured to cover the aluminum base plate substantially completely, the surface resistance value becomes very high, and when the present invention is applied to an electronic device, it is externally Since it is difficult to sufficiently remove the generated electromagnetic wave noise, for example, in a drive device, a writing or reproducing error is induced, or in a liquid crystal display, image noise or the like occurs.

Furthermore, the aluminum plate for electronic equipment according to the present invention, which is configured so that the base material of the aluminum base plate having the fine irregularities or the protrusions of the corrosion resistant coating are appropriately exposed on the surface of the resin coating, When applied to equipment,
It is noteworthy that the heat generated from this electronic device is efficiently radiated into the atmosphere through the exposed portion, so that the heat dissipation characteristics of this electronic device can be improved.

(Colloidal silica content of resin coating: 1 to 30% by mass based on the total resin coating) In the present invention, the resin coating included in the present invention is further hardened,
The scratch resistance can be improved. Therefore, the addition of colloidal silica having a relatively high hardness to the resin film has an advantageous effect on improving the scratch resistance. When the colloidal silica is added to the resin film in an amount of less than 1% by mass based on the total amount of the resin film, such an effect of improving scratch resistance cannot be sufficiently obtained, and When the amount of the colloidal silica added exceeds 30% by mass with respect to the total amount of the resin film, the hardness of the resin film becomes too high, so that the resin film may crack (peel) during press molding. It tends to occur. Therefore, in the present invention, it is desirable to add the colloidal silica in an amount of 1 to 30% by mass based on the total amount of the resin film.

[0051]

EXAMPLES The present invention will be specifically described below with reference to Examples according to the present invention and Comparative Examples which do not satisfy the requirements of the present invention. First, the aluminum base plates included in the above Examples and Comparative Examples were manufactured as follows. That is, first, a predetermined aluminum alloy was melted, and then an ingot of the aluminum alloy was produced through the steps of casting and homogenization treatment. Subsequently, an aluminum base plate (plate thickness: 0.5 mm, alloy type: AA5052-H34) was produced through each step of hot rolling, cold rolling and heat treatment. In the final (finishing) step of the cold rolling, the aluminum plate having various surface roughness (center line average roughness) was obtained by appropriately changing the surface roughness of the rolling roll.

Thereafter, the aluminum base plate is subjected to alkali degreasing, subsequently a corrosion resistant film is formed on the surface of the aluminum base plate, and a resin film is further formed thereon to form the aluminum of the above-mentioned examples and comparative examples. It was a plate. Table 1 shows the main structures of the aluminum plates of these examples and comparative examples. In this example, polyethylene wax was used as the lubricant.

Further, the surface roughness (center line average roughness Ra) of the aluminum base plates of the above-mentioned examples and comparative examples was measured by a surface roughness measuring machine (Kosaka Laboratory Ltd.) for each of these aluminum base plates. Manufactured by Surfcoder SE-30D), and scanned in a direction perpendicular to the rolling direction to obtain center line average roughness Ra (J
It was measured by determining IS B0601).

[0054]

[Table 1]

The aluminum plates thus produced in the above-mentioned Examples and Comparative Examples were evaluated by the following method. The results of these evaluations are shown in Table 2.

(Evaluation Method) <Conductivity> The conductivity is measured by the above-mentioned measuring method by an analog tester (SANWA ELECTRON INSTRU).
The surface resistance value of each aluminum plate was measured using MODEL CP-70 manufactured by MENT.

<Heat dissipation> The heat dissipation of the above Examples and Comparative Examples was measured as follows. First, each aluminum plate was cut into a 3.5-inch HDD cover shape for use as a HDD cover. Then, with these, with the surface on which the resin film is formed as the outside,
The HDD was covered, and heat was generated by operating the HDD to measure the temperature change on the surface of the aluminum plate with an electronic thermometer. And the heat dissipation of each
Judgment was made based on the temperature change when the bare aluminum plate was used, and the one whose maximum temperature reached was almost the same as that of the bare aluminum plate was marked as "○ (good)" and the aluminum blank What is higher than the bare material of "×
(Poor) "was evaluated.

<Moldability> The moldability of the above Examples and Comparative Examples is as follows. First, the resin film after bending is cracked (peeled).
As the evaluation of the property, it was evaluated by visually observing the state of cracking (peeling) of the resin film in each processed part when each of these aluminum plates was bent. Furthermore,
As a bending test, JIS H4001 No. 6.4
It was evaluated by a 180 ° bending test based on the bending test specified in the section. However, the inner radius is the same as the plate thickness (1T
Bending).

As a criterion for the cracking (peeling) state of the resin coating, "○ (good)" means that no cracking (peeling) was found in the resin coating, and a very slight crack in a part of the resin coating. Although there is a problem, there is no particular problem in quality control, "△ (generally good)" is given, and if there is a clear crack (peel) in the resin film, "x (bad)" is given. The formability of the examples was evaluated.

Further, in order to evaluate the lubricity of the aluminum plate surface which affects the formability, the friction coefficient was measured for each of the aluminum plates of the above-mentioned Examples and Comparative Examples. here,
If the friction coefficient of the aluminum plate is 0.2 or less,
It can be evaluated that there is no particular problem in the molding process that is usually performed in various electronic devices. This friction coefficient is measured by
By the Bowden method, three points randomly selected on the surface of each aluminum plate were measured, and the average value was adopted.

<Fingerprint resistance> Each fingerprint resistance was evaluated by measuring the color difference (ΔE) before and after the fingerprint was attached by touching the surface of each aluminum plate of the above-mentioned Examples and Comparative Examples with bare hands. . The color difference (ΔE) was measured using a color difference meter (CR-300) manufactured by Minolta.
When the color difference ΔE value was 0.5 or less, the fingerprint attached to the surface of the aluminum plate could hardly be confirmed with the naked eye.

<Scratch resistance> The pencil hardness was used as an index of the scratch resistance of the resin films in the above-mentioned Examples and Comparative Examples. That is, this pencil hardness is JIS K540
It was measured by the pencil scratch test specified in Section 08.4. This pencil scratch test is based on JISK5400
The test was performed according to the test method specified in Section 8.4.1, and the load was 9.8 N (1 kgf). From the above evaluation results shown in Table 2, the following is clear.

[0063]

[Table 2]

(Effect of Surface Roughness of Aluminum Base Plate (Centerline Average Roughness Ra)) Comparative Example 1 in which the centerline average roughness Ra is less than the lower limit value of the range regulated by the present invention is fingerprint resistance. , Scratch resistance, conductivity, and heat dissipation were deteriorated. Further, in Comparative Example 2 in which the center line average roughness Ra exceeds the upper limit value regulated by the present invention, the friction coefficient is as high as 0.26, and the resin film has a clear crack during molding ( Peeling) was observed.

(Effect of Corrosion Resistant Film Adhesion) In Comparative Example 3 in which the amount of Cr adhered to the corrosion resistant film is less than the lower limit of the range regulated by the present invention, the corrosion resistant film is coated on the entire aluminum base plate. However, it was inferior in corrosion resistance. In addition, the adhesion of the resin film was poor, and very slight cracks were observed in the resin film after the bending test. Furthermore, in Comparative Example 4 in which the amount of Cr deposited in the corrosion-resistant coating exceeds the upper limit value, very slight cracks were observed in the resin coating after the bending test.

(Influence of Average Thickness of Resin Coating) In Comparative Examples 5 and 6 in which the average thickness of the resin coating is less than the lower limit value of the range regulated by the present invention, the resin coating covers the entire aluminum base plate. Since it was not completely covered, the coefficient of friction increased (0.92 and 0.48, respectively), and cracks were observed in the resin film after the bending test, and the scratch resistance was also poor. Then, in Comparative Example 5, the fingerprint resistance was also deteriorated. Further, in Comparative Example 7 in which the film thickness of the resin film exceeds the upper limit value, the surface resistance because the base material of the aluminum base plate having fine irregularities or the projections of the corrosion resistant film are not exposed on the surface of the resin film The value was high and the heat dissipation was poor.

(Effect of Lubricant Amount) In Comparative Example 8 in which the amount of lubricant is less than the lower limit value regulated by the present invention, the coefficient of friction is high (0.77), and after the bending test, there is a clear resin film. Cracking (peeling) was observed and moldability was deteriorated. Further, in Comparative Example 9 in which the amount of the lubricant exceeded the upper limit, the scratch resistance was deteriorated.

(Influence of Addition Amount of Colloidal Silica) In Comparative Example 10 in which the addition amount of colloidal silica exceeds the upper limit value of the range regulated by the present invention, bending workability is poor and extremely slight cracks are formed in the resin film. I was seen.

On the other hand, the surface roughness (center line average roughness Ra) of the aluminum base plate, the amount of the corrosion resistant film deposited, the type of the resin film, the film thickness, and the amount of the lubricant contained in the resin film are all in the present invention. In Examples 1 to 10 satisfying the regulated range, it was confirmed that there was no problem in all of conductivity, heat dissipation, moldability, fingerprint resistance, and scratch resistance. It should be noted that the present invention is not limited to this embodiment, and can be appropriately modified as long as it is based on the technical idea of the present invention. For example, in this example, a resin film containing a lubricant composed of polyethylene wax was used, but the present invention uses other lubricants, that is, polyalkylene wax, microcrystalline wax, fluorine wax. The same effect as in this example can be obtained by using a lubricant containing at least one selected from lanolin wax, carnauba wax, paraffin wax and graphite contained in the resin film. To be

Furthermore, the present inventors have applied Examples 1 to 10 according to the present invention to electronic equipment,
It has been clarified that a molded article for electronic equipment, which is excellent in the above-mentioned characteristics, that is, conductivity, heat dissipation, moldability, fingerprint resistance, and scratch resistance, can be realized.

[0071]

According to the present invention configured as described above, the following effects can be obtained. That is, according to claim 1 of the present invention, since the center line average roughness Ra of the aluminum base plate and the average film thickness of the corrosion resistant film and the resin film are regulated to a predetermined film thickness, the fine unevenness is provided. The base material of the aluminum base plate or the projections of the corrosion resistant film are exposed on the surface of the resin film to a desired degree (dispersion degree), so that the desired conductivity and heat dissipation can be secured, and at the same time, molding It is possible to provide an aluminum plate for an electronic device, which has improved properties, fingerprint resistance, and scratch resistance.

According to the second aspect of the present invention, the resin film is made of at least one selected from polyester resin, urethane resin, epoxy resin and vinyl resin. In this case, the resin film easily follows due to the deformation of the aluminum base plate, and it is possible to provide an aluminum plate for electronic devices which is further excellent in formability.

Further, according to the invention of claim 3, the lubricant is selected from polyethylene wax, polyalkylene wax, microcrystalline wax, fluorine wax, lanolin wax, carnauba wax, paraffin wax and graphite. It is possible to provide an aluminum plate for an electronic device in which the surface of the aluminum plate is provided with appropriate lubricity and the formability is further improved because the aluminum plate is made of at least one of the above.

Further, according to the invention of claim 4, since colloidal silica having a relatively high hardness is added to the resin film, the resin film is further hardened and scratch resistance can be improved. As a result, it is possible to provide an aluminum plate for electronic devices with improved scratch resistance.

Further, according to the invention of claim 5, since the aluminum plate for electronic equipment is applied to a molded article for electronic equipment, it is excellent in conductivity, heat dissipation, moldability, fingerprint resistance and scratch resistance. It is possible to provide molded articles for electronic devices.

As described above, according to the present invention, the conductivity required for the casings and structural members of various electronic devices such as the case and chassis of the conventionally known drive device, the frame for fixing the liquid crystal panel and the back cover. In addition, while maintaining proper heat dissipation, it significantly reduces appearance defects due to fingerprints adhering to the surface and fine scratches on the surface. Furthermore, it has excellent surface lubricity and forms on the surface even after press molding. It is possible to provide an aluminum plate for electronic equipment in which cracking (peeling) of the resin film thus produced does not occur, and a molded article for electronic equipment using the same.

Further, according to the present invention, since the aluminum plate for electronic equipment having excellent moldability is used in the step of manufacturing the molded article for electronic equipment, the incidence of quality defects in press molding is reduced, The yield can be improved. Thereby, the present invention can reduce the overall cost of the molded article for electronic devices, as a result,
This greatly contributes to cost reduction of electronic device products.

[Brief description of drawings]

FIG. 1 is a sectional view schematically showing a configuration of an example of an embodiment according to the present invention.

FIG. 2 is a diagram schematically showing an example method for measuring the surface resistance value of an aluminum plate for electronic equipment according to the present invention.

[Explanation of symbols]

1 Aluminum plate for electronic equipment 2 Aluminum base plate 3 Corrosion resistant film 4 Resin film 10 Aluminum plate for electronic equipment 11 testers 12 Measuring rod made of metal with a spherical terminal at the tip

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) C23C 22/56 C23C 22/56 H05K 5/02 H05K 5/02 J F term (reference) 4D075 BB73Y BB74Y BB92Y BB92Z CA02 CA09 CA13 CA22 CA33 DA03 DA06 DB07 DC18 DC21 EA37 EB13 EB15 EB16 EB33 EB35 EB38 EC03 EC07 EC54 4E360 AB02 EE12 EE13 EE15 GA24 GA30 GA34 GA53 GB92 GC04 GC08 GC16 4F100 AA20C AB10A AB13B AB13H AB19B AB19H AJ11C AJ11H AK01C AK41C AK51C AK53C AR00B BA03 BA07 BA10A BA10C DD07A DE01B DE01H GB41 JB02B JG01 JJ01 JK14 JL01 JM02B YY00A YY00B YY00C 4K026 AA09 BA03 BA06 BA07 BA12 BB03 BB08 BB09 BB10 CA20 CA23 CA39 CA41 BC16 CA11 BC16 BC11 BA14 BA11 BA14 BA21 BA21 BA21 BA21 BA21 BA21 BA21 BA21 BA21 BA21 BA21 BA21 BA21

Claims (5)

[Claims] 1. The centerline average roughness Ra is 0.2 to 0.6 μm.
An aluminum plate in which a corrosion-resistant coating and a resin coating are sequentially formed from the base plate side on at least one surface of the aluminum base plate of m, wherein the corrosion-resistant coating contains Cr or Zr and has an adhesion amount of Cr or The Zr-converted value is 10 to 50 mg / m ² , the resin film has an average film thickness of 0.05 to 0.3 μm, and contains 1 to 25% by mass of the lubricant with respect to the total amount of the resin film. However, the aluminum base plate, or the surface on which the corrosion resistant film is formed, the fine projections are exposed on the surface of the resin film, the surface on the side where the resin film is formed, the tip portion. Has a radius of 10
An aluminum plate for electronic equipment, wherein a surface resistance value between the spherical terminal and the aluminum base plate is 1 Ω or less when a spherical terminal of mm is pressed with a load of 0.4 N. 2. The resin film is a polyester resin,
The aluminum plate for an electronic device according to claim 1, wherein the aluminum plate for an electronic device is composed of at least one selected from a urethane resin, an epoxy resin, and a vinyl resin. 3. The lubricant is polyethylene wax,
The polyalkylene wax, the microcrystalline wax, the fluorine wax, the lanolin wax, the carnauba wax, the paraffin wax, and at least one selected from the graphite, characterized in that it is composed of 1 or 2. Aluminum plate for electronic device described. 4. The electronic device according to claim 1, wherein the resin film contains 1 to 30% by mass of colloidal silica with respect to the total amount of the resin film. Aluminum plate. 5. A molded product for electronic equipment, which is molded using the aluminum plate for electronic equipment according to any one of claims 1 to 4.