JP2000067571A - 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 aluminum material having excellent deep formability which is severer and stronger working than bending together with box formability, high solvent resistance and excellent blocking resistance as well as a hard disk drive case and hard disk drive device free from the possibility of a malfunction or trouble by the gas generation from organic resin films. SOLUTION: The resin coated aluminum material for the hard disk drive case is the resin coated aluminum material constituted by forming the organic resin film consisting of a coating material compsn. contg. a polyester resin and a hardener on a ground surface film on one surface of an aluminum alloy plate formed with this ground surface film. The organic resin film is formed by curing the resin contg. the polyester resin having Tg of 0 to 10 deg.C and the polyester resin having Tg of 12 to 40 deg.C at a weight ratio of 90:10 to 40: 60 at a weight ratio of 90:10 to 40:60 of the total of two kinds of the polyester resins described above and the hardener. The film thickness thereof is >=0.5 to <=20 μm.

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 drive case by deep drawing. In addition, when forming an aluminum alloy plate into a hard disk drive case, a press forming oil or the like is often used, and a cleaning agent or the like is also used in accordance with this. However, the resin film coated on the aluminum alloy plate is resistant to these. If the solvent has low solvent resistance (hereinafter, referred to as solvent resistance), the film will be dissolved at the time of molding, causing problems such as impairing the appearance of the case. The present invention has been made in view of the above circumstances, and in addition to box formability, excels in deep drawing processability, which is a severe process that is more severe than bending, and has high solvent resistance. It is an object of the present invention to provide a resin-coated aluminum material for a lightweight hard disk drive case having excellent blocking resistance without sticking. 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) a resin-coated aluminum formed by forming an organic resin film from a coating composition containing a polyester-based resin and a curing agent on one surface of an aluminum alloy plate on which a base film is formed; Wood,
The organic resin film, wherein the resin containing a polyester resin having a Tg of 0 to 10 ° C and a polyester resin having a Tg of 12 to 40 ° C in a weight ratio of 90:10 to 40:60,
Weight ratio of the total of various polyester resins to the curing agent 90:
It is cured at 10 to 40:60 and has a thickness of 0.5
a resin-coated aluminum material for a hard disk drive case, which is not less than μm and not more than 20 μm,
(2) The resin-coated aluminum material according to (1), wherein the curing agent is an aminoplast resin, and (3) a lubricant containing a lubricant in the organic resin film. (2) The resin-coated aluminum material according to the above item,
(4) The resin-coated aluminum material according to (1), (2) or (3), wherein the organic resin film contains organic resin fine particles and / or inorganic fine particles having an average particle size of 1 to 20 μm. , (5) (1), (2), (3) or (4)
A hard disk drive case characterized in that the resin-coated aluminum material according to the above item is formed so that the surface having the organic resin film is outside the case, and a hard disk drive case according to the item (6) or (5). A hard disk drive characterized in that the hard disk drive is used. The aluminum material in the present invention includes aluminum and aluminum alloy. In this specification, the aluminum alloy plate includes an aluminum plate.

[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 undercoat, 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 on one side on a base film. In the present invention, the reason why the organic resin film is formed only on one side 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 inner surface of the case due to a rise in temperature during driving of the hard disk device is reduced. This is to prevent adverse effects of gas generation.

The organic resin film of the present invention is formed of Tg to ensure the adhesion of the organic resin film to the aluminum alloy plate, the formability such as deep drawing, mold release, blocking resistance, and solvent resistance. (Glass transition temperature) is 0
A polyester resin at 10 ° C., preferably 2 to 8 ° C. (hereinafter referred to as a low Tg polyester resin) and a Tg of 12 to
It is formed from a coating composition containing a polyester resin at 40 ° C., preferably 15 to 30 ° C. (hereinafter, referred to as a high Tg polyester resin). Examples of the polyester resin include oil-modified polyester and oil-free polyester, but are not particularly limited.
Further, a homopolymer or a copolymer may be used, and one kind may be used alone or a mixture may be used. It is preferable to use a polyester resin from the viewpoint of moldability and blocking resistance.
In the present invention, the weight ratio of the low Tg polyester resin to the high Tg polyester resin in the organic resin film is 90:
10:40:60, preferably 80: 20-5
0:50.

In the present invention, an organic resin film is formed by curing a resin containing the above two polyesters with a curing agent. The ratio of the curing agent is 90:10 to 40:60, preferably 8 in weight ratio of the total of the low Tg polyester resin and the high Tg polyester resin: the curing agent.
0:20 to 50:50. As the resin curing agent in the present invention, for example, aminoplast resins, blocked isocyanate compounds and the like can be used. An aminoplast resin, particularly preferably a melamine resin, is preferably used because of its excellent blocking resistance and solvent resistance, particularly excellent resistance to commonly used press molding oils and accompanying cleaning liquids. The polyester-based resin has a hydroxyl group, which seems to contribute to the reaction with the curing agent in the present invention.

In the present invention, a lubricant can be contained in the organic resin film, and it is preferable to use a fluororesin lubricant and / or wax as the lubricant. For example, as a fluororesin-based lubricant, monofluoroethylene, difluoroethylene, chlorotrifluoroethylene, a homopolymer of tetrafluoroethylene, or a copolymer thereof, furthermore, these and other fluorine-containing unsaturated monomers and Examples include a copolymer with an unsaturated monomer containing no fluorine. Examples of the wax include paraffin wax and polyolefin wax. In view of the strong workability, mold release properties, and blocking resistance of the resulting coating film, a particularly preferable example is a fine powder of polytetrafluoroethylene (hereinafter referred to as PTFE), which is a homopolymer of tetrafluoroethylene. No.
These are preferably used in an amount of 1 to 30% by weight based on the weight of the organic resin film, and may be added alone or in combination.

In the present invention, the organic resin film contains organic resin fine particles and / or inorganic fine particles having an average particle size of 1 to 20 μm in order to increase the hardness of the coating film and further improve the blocking resistance and the releasability. Preferably. When the average particle size is less than 1 μm, there is no effect of improving the blocking resistance and the releasability. When the average particle size exceeds 20 μm, the fine particles easily fall off at the time of molding and after molding, which causes poor appearance. Organic resin fine particles that can be used in the present invention include fine particles of polyamide resin, urethane resin, acrylic resin, urea resin and the like. Further, silica fine particles or the like can be used as the inorganic fine particles. These fine particles are preferably used in an amount of 1 to 25% by weight based on the weight of the organic resin film.

[0010] In addition to the above components, the coating composition of the present invention contains an organic solvent (xylene or the like) usually used in coatings.
Is used. In addition, organic resins (such as polyisocyanate resins) may be further added, if necessary, for the purpose of adjusting the properties of paints and coatings such as viscosity and flexibility of paints; leveling agents, flow regulators, ultraviolet stabilizers, and ultraviolet absorbers. Additives such as chemical agents and defoamers; organic pigments (such as carbon black), rust preventive pigments (such as zinc chromate), moisture-resistant pigments (such as silica), metal powders (such as aluminum powder), organic fibers (such as carbon fibers), Inorganic fibers, metal fibers and the like can be used.

The organic resin film in the aluminum material of the present invention can be obtained by applying the above-mentioned coating composition on only one surface of the aluminum material having the base film formed thereon and then heating and curing the composition. The heating and curing conditions can be appropriately selected depending on the polyester resin used for the coating composition.
Bake at ~ 300 ° C for 15-90 seconds. The organic resin film has a dry film thickness of 0.5 μm or more and 20 μm or less, preferably 5 μm or more and 15 μm or less. If it is less than 0.5 μm, severe forming processing (strong processing such as deep drawing)
If the conditions cannot be satisfied, and if it exceeds 20 μm, the appearance of the painted surface will be poor, and the film will peel off during the forming process, causing the generation of scum and deteriorating the continuous forming processability, and is not economical. As a coating method for forming the organic resin film, a roll squeezing method, a chemical coater method, a roll coater method, an air knife method, an immersion method, a spray method, an electrostatic coating method, or the like can be used. Method, a dielectric heating method, or the like.

[0012] 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 (the surface having an organic resin film) is outside the case. Is not particularly limited. Since the organic resin film of the aluminum material does not exist 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 an organic 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 by deep drawing or the like, but it is not particularly limited as long as it is a conventional press forming. 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.

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.

[0014]

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. Examples 1 to 14 and Comparative Examples 1 to 13 An aluminum alloy plate (A5182-O, 1 mm thick) was degreased with a fine cleaner 364S (trade name, manufactured by Nippon Parkerizing Co., Ltd.) and washed with water. Thereafter, a pretreatment shown in Table 1 is performed, a surface treatment is performed on the aluminum alloy surface, and then a paint shown in Table 2 is applied.
7 ° C.) to a reached metal plate temperature of 240 ° C., and then, in a process of washing and cooling with water, an organic film as shown in Table 2 was formed and used as a test material. Table 3 shows the test materials and evaluation results.
The details of the evaluation method are described below.

[0015]

[Table 1]

[0016]

[Table 2]

(Deep drawing formability) A volatile lubricating oil G-6284M (trade name, manufactured by Nippon Kogyo Oil Co., Ltd.) is applied to the obtained resin-coated aluminum alloy plate so that the organic resin film surface faces outward. The sheet was deep-drawn into a cylinder having a diameter of 40 mm, and the critical 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.

[0018]

(Equation 1)

(Box Formability Test) Box type press (size length 1)
(Examples 1 to 14, Comparative Examples 1 to 14)
11 is processed with the resin-coated surface as the outer surface).
The evaluation was performed based on the number of broken alloys out of 0000 molded pieces and the state of generation of organic resin residues. ：: No scum was generated. Δ: A small amount of scum was generated. X: A large amount of scum was generated.

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

(Solvent resistance) The obtained resin-coated aluminum alloy plate was gauze impregnated with volatile lubricating oil G-6284M (trade name, manufactured by Nippon Kogyo Oil Co., Ltd.), and the load was 200 g.
f and rubbed to evaluate whether the coating film was dissolved. ○: No change in coating film ×: Dissolution is seen in coating film

(Outgas Resistance) When the obtained resin-coated aluminum alloy plate was used as a hard disk drive case, the outgas resistance of the inner surface of the case was evaluated. The outgas resistance evaluation was performed on a case processed by a box press (Examples 1 to 14 and Comparative Examples 1 to 11
Acetone was put into the resin-coated surface, and left at room temperature for 24 hours. The solvent was concentrated, and the outgas component was analyzed by FT-IR. ：: No gas component was detected. X: Gas component was detected. Table 3 shows the evaluation results.

[0023]

[Table 3]

As apparent from Table 3, Examples 1 to 14
Are excellent in deep drawability, box moldability, blocking resistance, solvent resistance and outgas resistance. Above all, it was recognized that Examples 7 to 14 had more excellent blocking resistance.

On the other hand, in Comparative Example 1, since there was no undercoating treatment, the adhesion of the coating film was poor, and scum was generated during molding. Comparative Example 2 was poor in blocking resistance because a large amount of low Tg polyester resin was blended. Comparative Example 3 has a high Tg
Moldability could not be satisfied because a large amount of polyester resin was blended. In Comparative Example 4, since the Tg of the low Tg polyester resin was too low, the blocking resistance was poor, and the solvent resistance could not be satisfied.
In Comparative Example 5, since the Tg of the high Tg polyester resin was too high, the deep drawability was low, and cracks and scum occurred even in box molding. In Comparative Example 6, the amount of the curing agent was too small, so that the solvent resistance could not be satisfied. In Comparative Example 7, since the amount of the curing agent was too large, the moldability was low and many cracks occurred. In Comparative Example 8, an organic resin film was formed using only an acrylic resin, and the blocking resistance was poor. In Comparative Example 9, the organic resin film was formed only with the epoxy resin, and the molding processability was poor and many cracks occurred. Comparative Example 10 had a thin organic resin film and was inferior in moldability. In Comparative Example 11, the organic resin film was too thick, and scum was generated during molding. In Comparative Example 12, since no organic resin film was coated, the moldability was low. Comparative Example 13 had good moldability because both surfaces were coated with an organic resin film,
Organic substances were detected in the test for outgassing resistance.

Further, a hard disk drive for a desktop type personal computer was assembled using the hard disk drive case formed from the resin-coated aluminum alloy plate obtained in Examples 1 to 14, and the personal computer incorporating the hard disk drive was used for one month. It was operated for a while.
There were no failures and everything worked normally.

[0027]

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. Since it has excellent properties and excellent solvent resistance, 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.

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Yu Ota 2-6-1 Marunouchi, Chiyoda-ku, Tokyo Furukawa Electric Co., Ltd. F-term (reference) 4J038 DA112 DA162 DD001 DD002 DD231 DD232 JB18 KA03 MA13 NA04 PB09 PB11 PC02

Claims (6)

[Claims] 1. A resin-coated aluminum material having an organic resin film formed from a coating composition containing a polyester resin and a curing agent on one surface of an aluminum alloy plate having an undercoat film formed thereon. The organic resin film is made of a polyester resin having a Tg of 0 to 10 ° C. and Tg 1
A polyester resin at 2 to 40 ° C. is added in a weight ratio of 90:10 to 10:10.
The resin containing at a ratio of 40:60 is 90:10 to 40:60 by weight of the sum of the two polyester resins and the curing agent.
And the film thickness is 0.5 μm or more and 20 μm
A resin-coated aluminum material for a hard disk drive case, characterized in that: 2. The resin-coated aluminum material according to claim 1, wherein the curing agent is an aminoplast resin. 3. The resin-coated aluminum material according to claim 1, wherein the organic resin film contains a lubricant. 4. An organic resin film having an average particle size of 1 to 20 μm.
The resin-coated aluminum material according to claim 1, 2 or 3, comprising organic resin fine particles and / or inorganic fine particles. 5. A hard disk drive case, wherein the resin-coated aluminum material according to claim 1, 2, 3 or 4 is formed so that a surface having an organic resin film is outside the case. 6. A hard disk drive using the hard disk drive case according to claim 5.