JP2000067570A - Resin coated aluminum material for hard disk drive case, hard disk drive case using the same and hard disk drive device using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a resin coated material which has an excellent deep drawing characteristic, does not produce gases from the resin and has excellent blocking resistance by applying a coating film contg. a polyester resin contg. unsatd. polyester on the film on one surface of an aluminum alloy sheet formed with a ground surface film and crosslinking and curing this coating film, thereby forming the resin film of a film thickness in a specific range. SOLUTION: The film thickness of the resin film is >=0.5 to <=20 μm. The polyester resin is, for example, oil denatured polyester, oil-free polyester, etc. The unsatd. polyester is incorporated into the base resin and the resin is cured, by which the blocking resistance is improved. The reaction type ground surface film subjected to a chromate treatment, etc., is applied on the aluminum alloy sheet to improve the adhesion property and corrosion resistance of the resin. The resin film is formed on one surface of the ground surface film and the surface not formed with the film positioned on the inner side is molded to the hard disk drive case, by which the generation of the gases from the inside surface of the case by the temp. rise at the time of hard disk driving is prohibited.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a resin-coated aluminum material used for a case of a hard disk drive (HDD) device, a hard disk drive case using the resin-coated aluminum material, and a hard disk drive device using the case.

[0002]

2. Description of the Related Art A hard disk drive (HDD) is used as a storage medium for computers and word processors.
Conventionally, an aluminum die-cast material has been used. However, since the aluminum die-cast material is heavy, it is not preferable for use in portable, lightweight and miniaturized equipment. In addition, the anticorrosion treatment and the coloring treatment required for the aluminum die-cast material must be individually performed by painting or alumite treatment, and there is a problem in productivity and cost.

[0003]

Therefore, there has been proposed an aluminum alloy plate in which a chromate film is formed on an aluminum alloy plate, and an organic resin film containing a lubricant is formed thereon to improve the formability. JP-A-6-55137). However, this aluminum alloy plate has an organic resin film formed on both sides, and when this is used for electronic equipment parts, gas is generated from the organic resin film, and the parts may malfunction or break down, or However, the boards may stick together during transportation. Further, a lightweight aluminum plate for a floppy disk drive case having an organic resin film formed on one surface of an aluminum alloy plate and having excellent strength, moldability, and electromagnetic shielding properties has been proposed (Japanese Patent Publication No. 6-70870).
However, there is a problem that the material is broken when it is formed into a hard disk case by deep drawing. The present invention has been made in view of the above circumstances,
In addition to box formability, it excels in deep drawing formability, which is a severe processing that is more severe than bending processing, does not generate gas etc. from resin under stricter use conditions, and does not block sheets so that they do not stick together during transportation It is an object of the present invention to provide a resin-coated aluminum material for a lightweight hard disk drive case having excellent operability. Further, the present invention provides a hard disk drive case, which is durable for long-term use, has no risk of malfunction or failure due to generation of gas from the organic resin film coated on the aluminum material, and a hard disk drive device using the same. The purpose is to provide.

[0004]

Means for Solving the Problems The present inventors have made intensive studies in view of the above problems, and as a result, have solved the above problems by using an aluminum material formed by coating a specific organic resin film on one surface and a hard disk drive case processed therefrom. The inventors have found that the present invention can be solved, and have accomplished the present invention based on this finding. That is, the present invention provides (1) crosslinking and curing a coating film containing a polyester resin containing an unsaturated polyester, which is applied on one surface of an aluminum alloy plate on which an undercoat film has been formed, and 0.5 μm or more and 20 μm
A resin-coated aluminum material for a hard disk drive case, which is formed by forming the following resin film,
(2) The resin-coated aluminum material according to (1), wherein the resin film further contains a lubricant.
(4) A hard disk drive case, wherein the resin-coated aluminum material according to (1) or (2) is formed so that the resin film becomes an outer surface of the case.
(3) A hard disk drive characterized by using the hard disk drive case described in the item (3). The aluminum material in the present invention includes aluminum and aluminum alloy.

[0005]

Next, the present invention will be described in detail. The resin-coated aluminum material for a hard disk drive case according to the present invention is characterized in that an aluminum alloy plate on which an undercoat film is formed has an organic resin film on one surface. The undercoating in the present invention is preferably applied to the surface of the aluminum alloy plate in order to improve the corrosion resistance of both surfaces, but is not limited thereto. This undercoat is formed by an ordinary method on an aluminum alloy plate that has been subjected to a pretreatment such as a degreasing treatment, and the type thereof is not particularly limited, but a reactive undercoat such as a chromate type is preferred. By forming the base treatment, the adhesion and corrosion resistance of the organic resin to the aluminum alloy plate during and after molding are improved. The aluminum material of the present invention has an organic resin film layer on one side of a base film. In the present invention, the reason why the organic resin film is formed only on one surface is that the surface on which the organic resin film is not formed is formed inside to form a hard disk drive case, so that the temperature from the case inner surface due to a rise in temperature during driving of the hard disk is increased. This is to prevent adverse effects of gas generation.

The organic resin film according to the present invention is a polyester resin containing an unsaturated polyester in order to secure the adhesion of the organic resin film to the alloy plate, the formability such as deep drawing, the releasability, and the blocking resistance. Formed from a coating composition comprising: Examples of the polyester resin include an oil-modified polyester and an oil-free polyester, but are not particularly limited.
As the polyester resin as the base resin in the present invention, not an unsaturated polyester resin but a saturated polyester resin is used. In general, a melamine resin or the like can be used as a resin curing agent in the present invention. The polyester resin may be a homopolymer or a copolymer, and may be used alone or as a mixture. In the present invention, blocking resistance is improved by adding an unsaturated polyester to the base resin and curing the polyester. The content of the unsaturated polyester is preferably from 0.1% by weight to 20% by weight, more preferably from 0.1% by weight to 10% by weight, based on the solid content of the resin. The unsaturated polyester may be an ordinary polyester, for example, a polyester obtained by reacting an unsaturated acid and a polyol by a conventional method. To use this, a vinyl compound that also functions as an organic solvent, for example, a compound dissolved in styrene is used. Examples of the unsaturated acid include maleic anhydride, phthalic acid, and itaconic acid. As the polyol, a fatty acid polyol is preferable. For example, ethylene glycol, polypropylene glycol, 1,3-butanediol, 1,4- Butanediol, 1,5-pentanediol, neopentyl glycol, diethylene glycol, dipropylene glycol, triethylene glycol, tripropylene glycol and the like.

As the lubricant that can be used in the present invention, a fluororesin-based lubricant is preferred from the viewpoint of blocking resistance. For example, as a fluororesin system, monofluoroethylene, difluoroethylene, chlorotrifluoroethylene, a homopolymer of tetrafluoroethylene, or a copolymer between them, furthermore, these and other fluorine-containing unsaturated monomers or fluorine And a copolymer with an unsaturated monomer containing no. In view of the strong workability, mold release properties and blocking resistance of the resulting film, a fine powder of polytetrafluoroethylene (hereinafter referred to as PTFE), which is a homopolymer of tetrafluoroethylene, is particularly preferable. Is mentioned. The heat resistant temperature of the fluororesin that can be used in the present invention is 150 to 35.
The range of 0 ° C. is preferable, and these can be added alone or in combination of two or more so as to be 1 to 30% by weight. In the paint of the present invention, in addition to the above components, an organic solvent (xylene or the like) usually used for the paint is used. In addition, for the purpose of adjusting the properties of paints and coatings such as the viscosity and flexibility of paints, organic resins (such as polyisocyanate resins) may be further added, if necessary; leveling agents, flow regulators, ultraviolet stabilizers, ultraviolet absorbers Additives such as antifoaming agents and defoamers;
Organic pigments (such as carbon black), rust preventive pigments (such as zinc chromate), moisture-resistant pigments (such as silica), organic resin fine particles (such as phenolic resin), metal powders (such as aluminum powder), organic fibers (such as carbon fibers), and inorganic Fibers, metal fibers and the like can be used.

[0008] The organic resin film in the aluminum material of the present invention can be obtained by applying a paint to only one side of the aluminum material having the base film formed thereon and then heating and curing the coating. In the present invention, the polyester resin-based coating film is cross-linked and cured with a curing agent, for example, a melamine resin. Heat curing conditions can be appropriately selected depending on the polyester resin used for the paint,
Usually, baking is performed at 180 ° C. to 300 ° C. for 15 to 90 seconds. Organic resin film is 0.5μm or more and 20μm in dry film thickness
Or less, preferably 5 μm or more and 15 μm or less.
If it is less than 0.5 μm, it is not possible to satisfy strict forming conditions (strong processing such as deep drawing), and 2
If it exceeds 0 μm, the appearance of the painted surface will be poor, and the coating will peel off during the molding process, causing scum to be produced, resulting in reduced continuous molding processability and not economical. The coating method for forming the organic resin film includes a roll squeezing method, a chemical coater method, a roll coater method, an air knife method, a dipping method,
A spray method, an electrostatic coating method, or the like can be used, and drying can be performed by a general heating method, a dielectric heating method, or the like.

[0009] The hard disk drive case of the present invention is characterized in that the resin-coated aluminum material of the present invention is molded so that the resin-coated surface is outside the case. Since the resin film of the aluminum material is not inside the case, no gas is generated from the film due to a rise in temperature due to the drive of the magnetic disk and the reading device inside when used in a hard disk drive, thereby preventing malfunction and failure. In addition, since the outer surface of the case is coated with a resin film, fingerprints and stains are unlikely to adhere during handling after molding. As a forming method, a hard disk drive case can be formed by press forming such as deep drawing or the like, but the press forming is not particularly limited as long as it is press formed. There are various shapes of such a hard disk drive case depending on applications and capacities, but in the present invention, any shape may be used, and there is no particular limitation as long as the case incorporates a magnetic disk, a reading device, and the like. In particular, since the case of the present invention is lightweight, it can be suitably used for a word processor, a personal computer, and the like that want to reduce the weight. Also, the hard disk drive of the present invention is not particularly limited except that the hard disk drive case of the present invention is used.
The present invention can be applied to any of commonly used hard disk devices.

[0010]

EXAMPLES Hereinafter, the effects of the present invention will be described specifically with reference to Examples and Comparative Examples. However, the present invention is not limited to the following Examples unless it exceeds the scope of the claims. (A5182-O, 1mm
) Was degreased with a fine cleaner 364S manufactured by Nippon Parkerizing Co., Ltd., and washed with water. Thereafter, a pretreatment shown in Table 1 is performed, a base treatment is performed on the surface of the aluminum alloy, and then a paint shown in Table 2 is applied, heated from 25 ° C. in one minute to a reached metal plate temperature of 220 ° C., and then cooled. Then, an organic film as shown in Table 2 was formed to obtain a test material. The polyester resin used was a polyester resin manufactured by Dainippon Ink and Chemicals, Inc. (Beckamine L-117). The unsaturated polyester resin was prepared by reacting each acid component shown in Table 2 with propylene glycol at a molar ratio of 1: 1.
A resin dissolved in styrene at twice the weight ratio was used for this resin. Table 3 shows the test materials and the evaluation results together. Details of the evaluation methods are described below.

[0011]

[Table 1]

[0012]

[Table 2]

(Deep drawing formability) A volatile lubricating oil (G-6284M made by Nippon Kogyo Oil Co., Ltd.) is applied to the obtained aluminum alloy plate having an organic resin film so that the organic resin film surface is on the outside. Deep drawn into a cylindrical shape with a diameter of 40 mm,
The limit drawing ratio (LDR) was determined. In addition, L. D.
R. Is a value represented by the following formula, and a higher value indicates better moldability.

[0014]

(Equation 1)

(Box Formability Test) Box Type Press (Size Vertical 1)
00 mm, 70 mm in width and 15 mm in depth), and processed the test piece after surface treatment to obtain an aluminum alloy plate of 10 mm.
Evaluation was carried out based on the number of broken alloys out of 000 molded pieces and the occurrence of scum of the organic resin. ：: No scum was generated. X: A large amount of scum was generated.

(Blocking resistance test) The obtained resin-coated aluminum plate was heated to 80 ° C and a load of 40 kgf /
Pressure was applied for 24 hours at cm ² and peeled off with a force of 10 kgf to evaluate whether or not the plates were stuck together. Blocking resistance A: The plates did not stick to each other. ：: The plates slightly adhered to each other but were easily peeled. X: The plates were stuck together and did not peel off.

(Outgas Resistance) The inner surface of the obtained resin-coated aluminum plate was evaluated for outgas resistance.
Outgas resistance was evaluated by sealing the outer surface of the apparatus in a sealed container, leaving it at 80 ° C for 24 hours, washing the inside of the container with a solvent (acetone), and concentrating the obtained solvent. Outgas components were analyzed by FT-IR. Outgas resistance ：: No gas component was detected. X: Gas component was detected. Table 3 shows the performance evaluation results.

[0018]

[Table 3]

As apparent from Table 3, the present invention examples (1 to 1)
10) is excellent in deep drawing formability, box formability, blocking resistance and outgas resistance. Above all, it was recognized that the inventive examples (7 to 8) had further excellent moldability.

On the other hand, no. Sample No. 11 had no base treatment, so the adhesion of the coating film was poor, and scum was generated during molding.
No. No. 12 had poor blocking resistance. No. 1
In No. 3, the moldability could not be satisfied, but it is considered that the film thickness was too thin. No. In No. 14, it is considered that scum was generated during molding, but the film thickness was too large. No. 1
Since No. 5 was not coated with an organic resin, the moldability was not satisfied. No. Since No. 16 was coated on both sides, the moldability was greatly improved, but organic substances were detected in the outgas resistance test. No. No. 17 has excellent blocking resistance, but has extremely poor box moldability and poor deep drawability. N
o. No. 18 has poor blocking resistance.

[0021]

The resin-coated aluminum material of the present invention has excellent anti-blocking property during transportation by having the above-mentioned organic resin film on one side, and has strong formability such as deep draw molding as well as box formability. Because of the excellent workability, molding into a hard disk drive case having high workability can be performed well. Further, as for the outgassing property, since no gas is generated from the inner surface of the case and the corrosion resistance is high, it can be suitably used for a hard disk drive case, and an excellent hard disk drive case and hard disk drive device can be obtained.

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Yu Ota 2-6-1 Marunouchi, Chiyoda-ku, Tokyo Furukawa Electric Co., Ltd. F-term (reference) 4F100 AB10B AB31B AK41C AK44C AR00A BA03 BA07 BA10B BA10C CC00 EH46C EJ08C EJ64 EJ69 EK00 GB41 GB90 JA20C JB02 JL01 JM02A JM02C YY00C

Claims (4)

[Claims] 1. A coating film containing a polyester resin containing unsaturated polyester, which is applied on one surface of an aluminum alloy plate on which an undercoat film is formed, is cross-linked and cured to a thickness of 0.5 μm. A resin-coated aluminum material for a hard disk drive case, comprising a resin film having a thickness of not less than 20 μm. 2. The resin-coated aluminum material according to claim 1, wherein the resin film further contains a lubricant. 3. A hard disk drive case, wherein the resin-coated aluminum material according to claim 1 or 2 is formed so that the resin film becomes an outer surface of the case. 4. A hard disk drive using the hard disk drive case according to claim 3.