JP2001322203A - Resin-coated metal panel excellent in cleaning properties, hdd case using the same, and hdd apparatus using hdd case - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a resin-coated metal panel hard to bond metal fine pieces or dust and excellent in cleaning properties. SOLUTION: The resin coated metal panel excellent in cleaning properties is obtained by coating both surfaces of a metal panel with an organic resin. Since both surfaces of the metal panel are coated with the organic resin, the resin coated metal panel is prevented from the adhesion of metal fine pieces or dust generated by the dragging of a mold at the time of molding and excellent in cleaning properties. Accordingly, an HDD case made of metal is hard to generate dust, and an HDD apparatus using the HDD case is hard to generate trouble and develops industrially marked effect.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a resin-coated metal plate having excellent cleanliness, a hard disk drive (hereinafter referred to as HDD) case using the resin-coated metal plate, and a hard disk drive (HD).
The present invention relates to an HDD device using a D case.

[0002]

2. Description of the Related Art HDD devices have been used as storage media for computers and word processors, and an aluminum die-cast material has been used for the HDD case of the device. The aluminum die-cast material,
Since it is heavy, it is not suitable for portable equipment, and since the anticorrosion treatment and the coloring treatment (painting and alumite treatment) are performed one by one, the productivity is poor and the cost is high.

[0003]

SUMMARY OF THE INVENTION
The present inventors have proposed a metal plate for an HDD case having one surface coated with an organic resin (hereinafter abbreviated as “resin”) to improve press formability (Japanese Patent Laid-Open No. 10-249994). This metal plate is press-formed so that the resin-coated surface is on the outer surface of the case and the metal surface is on the inner surface of the case. There is a problem in that dust adheres, and these metal strips and dust float in the case when the disk is driven to rotate, causing a failure of the HDD device.

[0004] From such a fact, the present inventors have proposed HDDs.
We studied the cleaning of the inside of the case, and found that coating both surfaces of the metal plate with resin could prevent the attachment of metal flakes and dust, and further research led to the completion of the present invention. . An object of the present invention is to provide a resin-coated metal plate excellent in cleanliness, an HDD case using the metal plate, and an HDD device using the case.

[0005]

According to the first aspect of the present invention,
The resin-coated metal plate is excellent in cleanliness, characterized in that both surfaces of the metal plate are coated with an organic resin.

According to a second aspect of the present invention, the surface of the metal plate is subjected to a base treatment, and the surface of the metal plate is coated with an organic resin. It is.

According to a third aspect of the present invention, there is provided a resin-coated metal sheet having excellent cleanliness according to the first or second aspect, wherein the surface contact resistance of at least one surface is 1000Ω or less.

The invention described in claim 4 is the first, second, and third inventions.
A HDD case made of the resin-coated metal plate according to any one of the above, wherein the surface contact resistance of the inner surface of the case is 100.
This is an HDD case characterized by being 0Ω or less.

According to a fifth aspect of the present invention, there is provided H
An HDD device using a DD case.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The resin-coated metal plate of the present invention has both surfaces coated with a resin, thereby preventing adhesion of metal flakes and dust generated by galling during press molding.

In the present invention, any metal plate such as a steel plate, a stainless steel plate, an aluminum alloy plate, and a copper plate can be used as the metal plate, but those having excellent press formability such as deep drawing are preferable. When bending workability and mechanical strength are required in addition to press formability, a metal plate suitable for it is appropriately selected.

In the present invention, the resin may be coated directly on the metal plate. However, if the resin is coated after the base treatment, the adhesion and corrosion resistance of the resin film are improved. When an aluminum alloy plate is used, a chemical conversion treatment, an alumite treatment, plating, or the like is applied to the base treatment. It is preferable to use a chromate-based, zirconium-based, or titanium-based treatment liquid in the chemical conversion treatment in terms of productivity, cost, and performance stability (adhesion).

The thickness of the undercoat film formed using the above-mentioned chromate treatment solution is 3 to 300 mg in terms of chromium metal.
/ M ² is preferable, and if it is less than 3 mg / m ² , sufficient adhesion and corrosion resistance cannot be obtained, and if it exceeds 300 mg / m ² , the effect of improving the adhesion is saturated, which is uneconomical. A particularly preferred coating amount is 5 to 50 mg / m ² . In the chemical conversion treatment using the chromate-based treatment liquid, for example, a chromate treatment liquid (chromic acid 0.4 to 10 g / liter, phosphoric acid 1.5) maintained on a degreased metal plate at a temperature of 20 to 60 ° C.
-50 g / liter, and hydrofluoric acid 0.05-5
g / liter) is applied by spraying or dipping, followed by washing with water and drying.

In the present invention, the coating resin includes an epoxy resin, an alkyd resin, an acrylic resin, a urethane resin,
Any resin that enhances press moldability, such as a phenol resin, a melamine resin, and a polyester resin, is used. The resin is coated by a method of coating by dissolving or dispersing in a solvent or water, a method of bonding a film-like resin, or the like. Among them, the coating method is advantageous in terms of cost. If the coating thickness of the resin is too thin, mold seizure will occur, and if it is too thick, the shielding properties will be reduced, and the resin film will be easily peeled off, increasing dust. Therefore, the coating thickness of the resin is preferably 0.5 to 40 μm in dry thickness.

In the present invention, when the surface contact resistance of at least one surface of the resin-coated metal plate is set to 1000Ω or less and the HDD case is formed so that this surface is an inner surface, the shielding property of the HDD case is improved and electromagnetic waves generated from the HDD are improved. Is well absorbed by the inner surface of the HDD case, and malfunction of the HDD device is prevented.

The surface contact resistance of the resin-coated metal plate is 1000
Examples of the method of reducing the resistance to Ω or less include a method of adding conductive fine particles to a resin and a method of using an ion conductive resin. The conductive fine particles include Ni, Ag, Al, Si,
Alternatively, spherical, flake-like, rod-like, or other fine particles made of these alloys can be used. According to the resin film to which these conductive fine particles are added, not only the shielding property but also the mold galling is improved. If the amount of the conductive fine particles is too small, the shielding properties are not sufficiently improved, and if the amount is too large, the adhesiveness of the resin film is reduced, and the resin film becomes brittle and easily peeled to increase dust. Therefore, the added amount of the conductive fine particles is preferably 0.5 to 40% by weight. If the diameter of the conductive fine particles is too small, the conductivity will be reduced. If the diameter is too large, the conductive particles will be easily seized and the conductive fine particles will fall off. Therefore, the average particle size of the conductive fine particles is 0.5% of the dry thickness of the resin film.
About 5 times is preferable. As the ion conductive resin, a resin composition containing a compound having an unsaturated bond is used.

In the present invention, by adding a powder lubricant to the coating resin, the press formability is improved, and the surface tension of the resin is increased, so that dust is less likely to adhere. Polyolefin wax, petroleum wax, natural wax, fluororesin, and the like can be applied to the powder lubricant. These may be added plurally. In particular, a fluororesin is preferable because it enhances lubricity. As the fluororesin powder, monofluoroethylene,
Each polymer of ethylene difluoride, chlorotrifluoroethylene or tetrafluoroethylene, or a copolymer thereof,
Copolymers of the above polymers or copolymers with other unsaturated monomers (which may or may not contain fluorine) and the like can be mentioned. Among them, fine powder of polytetrafluoroethylene resin (PTFE) which is a polymer of ethylene tetrafluoride is preferable. If the content of the powder lubricant in the coating film is too large, the adhesion is reduced and dust is likely to be generated. Therefore, the content is preferably 20% by weight or less.

In the present invention, design properties can be obtained by adding a coloring pigment or a dye to the coating resin. Further, by adding a silica compound or an alumina compound, the resin film is strengthened and the moldability is improved.

[0019]

The present invention will be described below in detail with reference to examples. (Example 1) Aluminum alloy plate (A5182-O material,
Both surfaces (1 mm thick) were degreased using Fine Cleaner 364S manufactured by Nippon Parkerizing Co., Ltd., and then subjected to water washing, ground treatment, and application and baking of resin in this order to produce a resin-coated metal plate. The base treatment was performed by chromate treatment. Table 1 shows the composition of the resin used. The baking of the resin was performed under the condition that the resin was heated from 25 ° C. to 220 ° C. for 1 minute and cooled immediately after reaching 220 ° C.

Example 2 A resin-coated metal plate was manufactured in the same manner as in Example 1 except that the undercoating treatment was not performed.

Comparative Example 1 A resin-coated metal plate was manufactured in the same manner as in Example 1 except that the resin was not coated or only one side was coated.

Each of the resin-coated metal plates produced in Examples 1 and 2 and Comparative Example 1 was subjected to (1) deep drawability,
(2) Actual press formability, (3) Cleanability, and (4) Shielding property were evaluated. Table 2 shows the results. (1) As shown in FIG. 1, the deep draw formability is obtained by cutting a blank 1 having a diameter of 84 mm from a resin-coated metal plate, and setting a cylindrical surface between a punch 2 and a die 3 having a diameter of 40 mm with the inner surface of the case facing upward. The sample was deep drawn, and the sample height at break was measured and evaluated. The sample height at break is 10.
0 mm or more was evaluated as good (○), and less than 10.0 mm was evaluated as poor (x). Deep drawing was performed by applying volatile lubricating oil G-6284M (trade name, manufactured by Nippon Kogyo Oil Co., Ltd.) to both surfaces of the blank 1. (2) The actual press formability is as follows: a resin-coated metal plate cut to a predetermined size is 140 mm long, 100 mm wide, and 15 mm deep.
Of the HDD case was press-formed, and the number of cases where cracks occurred in the case and the number of cases where the resin film was damaged were counted and evaluated. The case cracking was determined to be good (O) when no crack occurred, and poor (X) when even one crack occurred. If the number of scratches on the resin film was 30 or less, it was judged as good (（). Press molding was performed by applying the volatile lubricating oil to both surfaces. (3) The cleanliness was evaluated by immersing the normal HDD case obtained in (2) in water and measuring the number of dust particles with a particle counter device using ultrasonic waves. When the maximum number of dust particles having a diameter of 1 μm or more was 3000 or less, it was judged as good (（), and when it exceeded 3000, it was judged as poor (×). (4) The shielding performance was evaluated by examining the electromagnetic shielding performance of the inner surface of the case by a conventional method. When the shielding property was particularly excellent, it was judged as very good (（), and when there was no practical problem, it was judged as good (○).

[0023]

[Table 1]

[0024]

[Table 2]

As is clear from Table 2, N of the present invention example
o. All of Nos. 1 to 19 are excellent in deep drawing formability, actual press formability, cleanliness, and shielding properties. No. In No. 8, since a lubricant was added to the resin, the deep drawability and the actual press moldability were particularly excellent. No. No. 16 has a small amount of conductive fine particles. No. 17 has a small average particle size of the conductive fine particles. No. 18 did not contain conductive fine particles, and thus all had slightly poor shielding properties. On the other hand, in Comparative Example No. In Nos. 20 and 21, a large amount of dust adhered because the inner surface of the case was not covered with resin. In particular, no. In No. 21, since both surfaces were not coated with the resin, the deep drawing formability and the actual press formability were also reduced.

[0026]

As described above, since the metal plate of the present invention is covered with resin on both surfaces, adhesion of metal flakes and dust generated by galling during press molding is prevented. It is excellent in cleanliness. Therefore, the metal plate HDD
The case hardly generates dust and the like, and the HDD device using the HDD case hardly breaks down. In addition, when the resin is coated after the base treatment, the adhesion of the resin coating layer is increased, and the press formability and the corrosion resistance are improved. Further, when the surface contact resistance of the inner surface of the HDD case is set to 1000Ω or less, the shielding property of the HDD case is improved, and the HDD device functions better. Therefore, an industrially remarkable effect is achieved.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of deep drawing.

[Explanation of symbols]

 1 blank 2 punch 3 die

Claims (5)

[Claims] 1. A resin-coated metal plate excellent in cleanliness, wherein both surfaces of the metal plate are coated with an organic resin. 2. The resin-coated metal plate having excellent cleanliness according to claim 1, wherein the surface of the metal plate is subjected to a base treatment, and an organic resin is coated thereon. 3. The surface contact resistance of at least one side is 100.
3. The resin-coated metal sheet having excellent cleanliness according to claim 1, wherein the metal sheet has a resistance of 0 Ω or less. 4. An HDD case comprising the resin-coated metal plate according to claim 1, wherein a surface contact resistance of an inner surface of the case is 1000Ω or less. . 5. An HDD device using the HDD case according to claim 4.