JP2001162223A - Resin coated aluminum alloy material for memory medium drive case - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a resin coated aluminum alloy material for a memory medium drive case having high strength and excellent slide properties, fingerprint resistance and corrosion resistance and also having excellent conductivity and capable of being easily grounded. SOLUTION: A resin coated aluminum alloy material for a memory medium drive case is constituted by forming a synthetic resin film, which contains 10-200 parts by mass of a substance having conductivity per 100 parts by mass of a synthetic resin and has a surface resistance value of 100 Ω or less and a film thickness of 20 μm or less, on both surfaces of an aluminum alloy panel with an Mg content of 2.0-6.0 mass %. This aluminum alloy material has tensile characteristics such that tensile strength is 210-410 MPa and yield strength is 150-370 MPa.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a personal computer (PC) and other computer-related equipment.
-ROM (compact disc-read only memory), DVD
The present invention relates to a resin-coated aluminum alloy material for a recording medium drive case suitable for a drive case in a drive device for operating a storage medium such as a (digital video disk), a magneto-optical disk, and a micro floppy disk. In the present invention, the drive case also includes a chassis for fixing the drive case to the main body of the personal computer.

[0002]

2. Description of the Related Art CD-ROs are used in word processors, personal computers and other computer-related equipment.
Drive devices for operating recording media such as M, DVD, magneto-optical disk, optical disk, and micro floppy disk include devices for reading information from a recording medium, writing information on a recording medium, and devices for driving a recording medium. In order to protect these device components and the recording medium itself, these device components are housed in a case having an upper lid and a lower lid member.

[0003] Since these drive cases are installed near a CRT (cathode ray tube) in a word processor, personal computer and other computer-related equipment, electromagnetic noise generated from the CRT and minute current generated when the equipment is driven. This may cause problems such as insufficient reading of information from a storage medium contained in the drive device and poor writing to the storage medium. Therefore, it is necessary to prevent a minute current from flowing into the drive device by grounding the drive device so as not to hinder the memory of these storage media.

[0004] As for the method of grounding, a method of connecting a ground wire directly in the drive device and a member having excellent conductivity such as a leaf spring made of stainless steel (SUS) are brought into contact with the surface of the drive case. And other methods have been implemented. In addition, in order to take the ground from the drive case, the surface and the end face of the material forming the drive case need to have conductivity.

[0005] Further, since the storage medium generates heat during operation, it is necessary to release the heat through the drive case. Therefore, the drive case needs to be formed of a material having excellent heat conductivity such as metal. There is.

Further, since these drive devices are configured to be attached to and detached from word processors, personal computers and other computer-related devices, they are frequently attached and detached. In such a case, since the drive case is directly touched with bare hands, fingerprints adhere to the case. Thus, if the fingerprint attached to the case is conspicuous, the appearance of the case is impaired. In addition, when the drive case comes into contact with the surroundings when removing the drive device, or comes into contact with parts for fixing the drive device when attaching the drive device to a word processor, a personal computer and other computer-related equipment, the surface of the drive case may be reduced. Scratches and impair the appearance. Furthermore, during the forming of the drive case and the assembling of the drive device, there is a possibility that the surface may be scratched or a fingerprint may be attached, and this also impairs the appearance.

In recent years, portable devices such as notebook word processors, laptop and notebook personal computers and mobile devices have been developed.
A reduction in weight is required, and accordingly, a drive device mounted on these devices is also required to be reduced in weight.

Conventionally, the materials used for the cases of these drive devices are mainly SPCC (cold rolled steel sheet and steel strip), galvanized steel sheet and chromate steel sheet from the viewpoint of requiring conductivity. Steel sheets are used. However, when these steel plates are used, their weight becomes heavy, and they have become unsuitable for reducing the weight of these computer devices due to their portability. In addition, these steel sheets are liable to cause scratches on the surface of the case when forming the drive case, assembling the drive device, and attaching / detaching the drive case to / from the device. There is a point.

[0009] From the viewpoint of reducing the weight of devices such as personal computers accompanying portability, there is a method in which untreated aluminum alloy plates are used for drive cases instead of steel plates. However, an untreated aluminum alloy plate has a problem that the surface is easily scratched, as in the case of the above-described steel plates.

[0010] Further, as a conductive metal plate used for home electric appliances and the like requiring grounding properties, a metal plate in which a synthetic resin coating containing a conductive substance is formed on an aluminum alloy plate has been disclosed. (For example, JP-A-7-29025,
7-313930, 7-314601, etc.). In such a metal plate, the strength and conductivity of the metal plate are improved by defining the thickness of the synthetic resin film to be formed, the ratio of a conductive substance in the film, and the like (conventional example 1).

Further, in order to solve the problems caused by surface scratches and the adhesion of fingerprints, Japanese Patent Application Laid-Open No. 4-330683 discloses a technique of coating a resin containing a lubricant on an aluminum alloy plate. Conventional example 2). According to this, one surface of an aluminum alloy plate is coated with an epoxy-based, acrylic-based, or PVC-based resin, and the resin coating film has a thickness of 0.5 to 1.5 μm and a lubricant of 0 to 1.5 μm. 2 to 5% by mass, and the coefficient of friction is set to 0.50 or less.

Furthermore, Japanese Patent Application Laid-Open No. 6-346178 discloses an aluminum alloy material for a shutter of a sheet-shaped recording medium cassette which is lightweight and has improved slidability, fingerprint resistance and corrosion resistance (prior art). Example 3). according to this,
Mg: 3.0 to 6.0% by mass, the balance being Al and unavoidable impurities, tensile strength: 310 to 410
A synthetic resin-based coating film having a thickness of 20 μm or less is formed on the surface of an aluminum alloy plate having a MPa and a proof stress of 250 to 370 MPa.

[0013]

However, in the metal plate described in the prior art example 1, the strength required for the drive case is reduced.
Workability and conductivity cannot be obtained. Further, in the technology of the conventional example 2, if a resin coating film containing a lubricant is formed on the surface of the aluminum alloy plate, the surface becomes insulative. It is extremely difficult to ground the drive case. Further, in the technology of the conventional example 3, the desired conductivity is not obtained on the surface of the aluminum alloy plate having the synthetic resin-based coating film formed on the surface, and similarly, it is difficult to ground the drive case. There is a point.

The present invention has been made in view of the above problems, and has high strength, excellent sliding properties, fingerprint resistance and corrosion resistance, and excellent electrical conductivity, and is easy to ground. It is an object of the present invention to provide a resin-coated aluminum alloy material for a recording medium drive case that can be used for a recording medium.

[0015]

According to the present invention, a resin-coated aluminum alloy material for a storage medium drive case according to the present invention comprises Mg:
An aluminum alloy plate containing 2.0 to 6.0% by mass, and a synthetic resin film formed on the surface thereof with a thickness of 20 μm or less.
It is characterized by containing 10 to 200 parts by mass of a conductive material with respect to parts by mass, having a surface resistance value of 100 Ω or less, a total tensile strength of 210 to 410 MPa, and a proof stress of 150 to 370 MPa. And

In the present invention, since the aluminum alloy plate contains 2.0 to 6.0 mass% of Mg, the strength is high, and the synthetic resin film formed on the surface of the aluminum alloy plate has a predetermined amount of a conductive material. , It has excellent corrosion resistance, fingerprint resistance, slidability, corrosion resistance and conductivity.

Further, the surface of this aluminum alloy plate is
When there is a concentric annular groove having a surface roughness Ra of 2 μm or less, the adhesiveness of the synthetic resin film formed on the aluminum alloy plate is improved, and the formability of the material, such as bending property and overhang property, is further improved. Also, the surface can be provided with sharpness.

The resin-coated aluminum alloy material for a storage medium drive case according to the present invention is obtained by subjecting an ingot of an aluminum alloy containing Mg: 2.0 to 6.0 mass% to a homogenizing treatment, followed by hot rolling or ingot rolling. Hot rolling and cold rolling, intermediate annealing, and a rolling reduction of 20 to 90%.
Final cold rolling, the surface roughness Ra 0.1 to 2.0μ
m and a stabilizing heat treatment at a temperature of 250 ° C. or lower, or without a stabilizing treatment, a material having a conductivity of 10 to 100 parts by mass of the synthetic resin on the surface of the aluminum alloy plate is 10 to Contains 200 parts by mass and has a film thickness of 20 μm
And a step of forming a synthetic resin film described below.

In this manufacturing method, since the final cold rolling of the aluminum alloy sheet is performed at an appropriate rolling reduction, appropriate strength for use as a drive case is obtained, and the surface of the aluminum alloy sheet after the final cold rolling is obtained. Has an appropriate surface roughness Ra, so that the adhesiveness between the synthetic resin film formed thereafter and the aluminum alloy plate is excellent, the synthetic resin film is hard to peel off, and furthermore, since this synthetic resin film has conductivity, The material has a low surface resistance and is excellent in corrosion resistance, fingerprint resistance, slidability, corrosion resistance and conductivity.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a resin-coated aluminum alloy material for a storage medium drive case (hereinafter, referred to as an aluminum alloy material) according to an embodiment of the present invention will be described.
In order to solve the above-described problems, the inventors of the present application have determined that strength, optimum conductivity, slidability (scratch resistance), fingerprint resistance, etc., which are optimal for a drive case material using an aluminum alloy in a recording medium drive device. As a result of extensive research on the aluminum alloy composition and its surface treatment for obtaining aluminum, we found the optimal Mg content for improving the strength of the aluminum alloy, and found that the conductive material was added to the synthetic resin film formed on the aluminum alloy plate. It has been found that the inclusion of the compound makes it possible to obtain the conductivity required for the use of the drive case.

In the present invention, Mg is added in the range of 2.0 to 6.
A synthetic resin film containing a conductive substance is formed with a thickness of 20 μm or less on the surface of an aluminum alloy plate containing 0% by mass. The aluminum alloy plate may have Mn if necessary.
Is 0.5% by mass or less, Fe is 0.5% by mass or less, Si is 0.3% by mass or less, Cr is 0.5% by mass or less, Cu is 0.3% by mass or less, and Ti is 0.1% by mass. % Or less. Further, the synthetic resin film can be formed by applying a synthetic resin paint composed of a synthetic resin, a conductive substance, and a solvent to an aluminum alloy plate.

As a substance having conductivity, for example, N
selected from the group consisting of metal powders composed of metals such as i, Cu, Ag, Zn, Cr, Fe, Co, and Al; alloy powders composed of two or more alloys of these metals; and carbon powders (graphite powders). One or more powders can be used. In addition, scale-like Ni powder can be used. In this case, the scale has a thickness of 2.0 μm or less, an average diameter of 30 μm or less, and a maximum value of 1 μm.
Those having a size of 00 μm or less are preferred.

The synthetic resin is, for example, one selected from the group consisting of polyester resin, alkyd resin, ethylene acrylic resin, epoxy resin, epoxy acrylic resin, urethane resin and fluorine resin.
More than one type of resin can be used.

Further, the synthetic resin film may contain a wax of 3 parts by mass or less based on 100 parts by mass of the synthetic resin. Examples of the wax include polyethylene, microcrystalline, polytetrafluoroethylene, and the like. (PTE
F) One or more selected from the group consisting of synthetic compound waxes such as fluorine-based waxes and fat-based waxes such as lanolin and carnauba wax can be used.

The synthetic resin paint has no conductivity because the conductive substances are dispersed independently of each other and are not in contact with each other.
However, the synthetic resin film formed by applying this synthetic resin paint to an aluminum alloy plate and drying it has a volume that is reduced by removing the solvent contained in the paint as compared with the state of the paint. Is compressed. At this time, the conductive substances that have been dispersed independently in the coating material are connected to each other in a chain form, thereby exhibiting conductivity. In other words, by forming a synthetic resin film on the aluminum alloy plate, the conductive substances contained in the synthetic resin paint are mutually connected from the interface between the film and the aluminum alloy plate to the surface of the film in the synthetic resin film. A chain-like state is formed. As a result, the conductive substance contained in the synthetic resin film is present in the film in a state where the conductive material is connected to the surface of the film from the interface between the aluminum alloy plate having excellent conductivity and the film surface in a chain manner. In addition, conductivity is exhibited in the aluminum alloy material on which the synthetic resin film is formed. In addition, even when a conductive material having a particle size greater than the thickness of the synthetic resin film to be formed is used, the conductive material alone has an excellent conductivity from the interface between the aluminum alloy plate and the film to the surface of the film. Due to the presence, conductivity of the material surface is exhibited. By such a mechanism, the synthetic resin film exhibits conductivity, that is, when this synthetic resin film is formed on an aluminum alloy plate, an aluminum alloy material having a low surface resistance can be obtained. Such a synthetic resin film is obtained by applying a synthetic resin paint containing a predetermined component to an aluminum alloy plate by a method such as a roll coating method, and then drying the plate at a temperature of 150 to 300 ° C. for 5 to 120 seconds. Can be formed.

As a result, since the aluminum alloy material according to the present invention has excellent conductivity, a method of directly connecting a ground wire to the drive case and a method of bringing a member having excellent conductivity into contact with the drive case surface. In this case, grounding can be easily achieved by obtaining sufficient electrical continuity at the contact. In addition, since the synthetic resin film formed on the aluminum alloy material has a lubrication improving effect, it has an effect of improving the slidability when the recording medium drive device is attached to and detached from a word processor, a personal computer, and other computer-related devices. In addition, scratches generated on the surface of the aluminum alloy material can be prevented.
In addition, this synthetic resin film acts as a lubricant during press forming such as bending and overhanging when pressing the aluminum alloy material into the shape of the drive case, and reduces wear of the press forming die. In addition, volatile press oil can be used as a lubricant used in press forming. Furthermore, since the surface of the synthetic resin film does not easily adhere to water and oil, when the aluminum alloy material on which the synthetic film is formed is directly touched with bare hands, fingerprints due to water and oil such as sweat adhering to the hand may be generated. It is hard to adhere and fingerprints are not noticeable. That is, it has excellent fingerprint resistance. As a result, the appearance is not degraded due to fingerprint marks even when the material surface is touched with bare hands, and therefore, when the drive case is press-formed, during the assembling process after processing, or when the recording medium drive device is attached to or detached from a computer-related device. Handling becomes better.

An aluminum alloy material having a thickness of 20 μm or less and a synthetic resin film having a conductive material content of 10 to 200 parts by mass with respect to 100 parts by mass of the synthetic resin has a tensile strength of 210 parts by mass. Since the material has strength characteristics of up to 410 MPa and proof strength of 150 to 370 MPa, it is necessary and optimum strength as a material suitable for a drive case, conductivity of material surface, fingerprint resistance, corrosion resistance, durability, light weight, molding. It can have workability and slidability (scratch resistance).

Hereinafter, the reasons for limiting the numerical values in the present invention will be described.

Mg content of aluminum alloy plate: 2.0
-6.0 mass% Mg has the effect of promoting work hardening during cold rolling of an aluminum alloy and improving the material strength. However, when the content of Mg is 2.0% by mass or less, the effect of improving the strength of the alloy is small. On the other hand, when the content of Mg is 6.0% by mass or more, rolling or working becomes difficult, and bending (90-0 ° R bending) performed when forming the upper and lower lids of the drive case is performed. The formability such as the bending formability to perform and the overhang formability to perform the overhanging process is reduced. Therefore, the Mg content of the aluminum alloy plate is 2.0 to 6.
0 mass%.

The aluminum alloy of the present invention can further improve various material properties by adding Mn, Fe, Si, Cr, Cu and Ti as necessary.

Mn is added as necessary to the aluminum alloy because it has the effect of improving the material strength in the same manner as Mg. However, if the added amount exceeds 0.5% by mass, the material is bent. Moldability such as moldability is reduced. Therefore, the preferred range of the Mn content is 0.5% by mass.
It is as follows.

Fe is added as necessary to the aluminum alloy, which has the effect of refining the crystal grains and improving the bending performance, but is added as necessary. A coarse intermetallic compound consisting of Al-Fe-Mn is formed. If such inclusions are formed, the inclusions will serve as starting points during the forming process to cause cracks, thus reducing the formability. Therefore, Fe
A preferable range of the content is 0.5% by mass or less.

Since Si has the effect of improving the material strength similarly to Mg and Mn by being added to the aluminum alloy, Si is added as necessary. However, if the added amount exceeds 0.3% by mass, intermetallic Invites coarsening of the compound,
Moldability such as bending workability of the material is reduced. Therefore, Si
A preferable range of the content is 0.5% by mass or less.

When Cr is added to an aluminum alloy containing Mg to have an effect of controlling the stress corrosion cracking resistance of the aluminum alloy, Cr is added as needed. If it exceeds, the formability such as rolling workability and bending workability and the corrosion resistance decrease. Therefore, a preferable range of the Cr content is 0.3% by mass.

By adding Ti to the aluminum alloy, it has the effect of refining the structure when the aluminum alloy is melted to form an ingot and making the material characteristics uniform, and is added as necessary. If the amount exceeds 0.1% by mass, an extremely large intermetallic compound is formed during casting, which impairs formability such as bending of the material. Therefore, the preferable range of the Ti content is 0.1% by mass or less.

Tensile strength of resin-coated aluminum alloy material:
210-410MPa, yield strength: 150-370MPa
a ) Tensile strength and proof stress, which are the tensile properties of the aluminum alloy material on which the synthetic resin film is formed, are 410 and 370, respectively.
If it exceeds MPa, the strength becomes too high, and the bending workability and the forming workability such as overhang forming when working into a drive case are reduced. On the other hand, the tensile strength and proof stress were 2
If it is less than 10 or 150 MPa, the strength is low and it is not suitable for use as a drive case. Therefore, the tensile strength is 210 to 410 MPa and the proof stress is 150
To 370 MPa. In order to obtain the tensile properties of such a resin-coated aluminum alloy material, the tensile strength of the aluminum alloy plate before forming the synthetic resin film is at least 210 to 410 MPa, and its proof strength is 150 to 370 MPa. And

Thickness of synthetic resin film: 20 μm or less The conductive material contained in the synthetic resin film has a greater specific gravity than synthetic resin in many cases. If the specific gravity is heavy, the conductive substance contained in the synthetic resin film tends to concentrate at the interface between the film and the aluminum alloy plate forming the film when the synthetic resin film is formed. When the thickness of the synthetic resin film exceeds 20 μm, the conductive material is concentrated at the interface between the film and the aluminum alloy base plate, and the conductive material becomes thin near the film surface, and the above-mentioned conductive materials come into contact with each other. The effect of the chain-like contact is reduced, which reduces the conductivity of the material surface. Therefore, the thickness of the synthetic resin film is set to 20 μm or less.

To 100 parts by mass of the synthetic resin in the synthetic resin film
Content of conductive substance with respect to : 10 to 200 parts by weight When the conductive substance is less than 10 parts by weight with respect to 100 parts by weight of synthetic resin, the conductive substance in the synthetic resin film becomes thin, so that a film is formed. In this case, since the conductive substances do not come into contact with each other and become independent from each other, it is difficult to obtain a contact effect, and the conductivity of the material surface becomes insufficient. on the other hand,
When the conductive material is contained in an amount of more than 200 parts by mass with respect to 100 parts by mass of the synthetic resin, sufficient conductivity is obtained, but the conductive material is hardly fixed to the synthetic resin, and the conductive material is removed from the synthetic resin film. It is easy to drop. Due to this, the conductivity of the material is reduced, and further, at the time of press forming,
When the drive case is assembled and when the recording medium drive device is attached to / detached from a word processor, a personal computer, and other computer devices, the conductive material is lost, causing a failure in related components. Therefore, synthetic resin 1
The content of the conductive substance is 10 to 20 parts by mass
0 parts by mass.

As the conductive substance, Ni, Cu,
A metal powder composed of a metal such as Ag, Zn, Cr, Fe, Co, and Al; an alloy powder composed of two or more alloys of these metals; and one selected from the group consisting of a carbon powder (graphite powder) and the like It is preferable that the above powder is used. The volume resistivity of these substances is as low as 10 ⁻⁵ Ω · cm or less, and they show extremely excellent conductivity. That is, a synthetic resin paint having a volume specific resistance value of 10 ¹² Ω · cm or more and containing a synthetic resin having an insulating property,
When a conductive material having such excellent conductivity is contained and the synthetic resin coating is applied to form a synthetic resin film, conductivity of the aluminum alloy material surface can be obtained. Therefore, the conductive substance has a volume resistivity of 10 ^−5.
It is only necessary to be as low as about Ω · cm, and it is not limited to the substances listed above.

If the Ni metal powder of the conductive material is in the form of scale, it is preferable that the thickness is 2.0 μm or less, the maximum value of the major axis is 100 μm or less, and the average value is 30 μm or less. Ni has a volume resistivity of about 7 × 10 ⁻⁶ Ω
-Cm, low, and extremely excellent in conductivity, it is a very preferable conductive material, and when the average value of the major axis of the flaky Ni powder is 30 µm or less, the dispersibility in the synthetic resin paint is low. It will be good. However, if the thickness of the flaky Ni powder exceeds 2.0 μm or / and the maximum value of the major axis exceeds 100 μm, it is difficult to disperse the powder in the synthetic resin paint. When the dispersibility of the flaky Ni powder in the paint is reduced, the conductive substance is applied to the inside of the paint tank when the synthetic resin paint is applied to the aluminum alloy plate by a roll coater method, a knife coaster method, a spray method or the like. Accumulate below the
As a result, the content of the conductive substance in the synthetic resin film formed by using this decreases, or the conductive substance concentrates at the interface between the synthetic resin film and the aluminum alloy plate, thereby causing the conductive substance to be concentrated. The contact effect is reduced, and sufficient conductivity cannot be obtained. Such scaly Ni
Can be formed by obtaining nickel powder by pyrolysis of nickel tetracarbonyl (Ni (CO) ₄ ) and then mechanically crushing it.

Further, the synthetic resin film may contain wax. The wax has the effect of further improving the lubricity of the film surface, thereby further improving the slidability of the aluminum alloy material and preventing the occurrence of scratches. In addition, when the lubricity of the aluminum alloy material surface is improved, the amount of volatile press oil usually applied to impart lubricity during press forming is reduced, or molding without oil (lubrication-free molding)
Becomes possible. However, if the content of wax is
If the amount exceeds 3 parts by mass with respect to 00 parts by mass, a synthetic resin paint is applied and dried to form a resin and harden. At this time, an excessive wax component is discharged to the outside of the resin system, and the film surface A large amount of wax is unevenly distributed. Such unevenly distributed wax accumulates in a press die during press molding, or attaches or detaches a component such as a computer device when attaching or detaching a recording medium drive case to a computer-related device or the like. Causes problems such as adhesion to Further, the wax unevenly distributed on the film surface covers the conductive substance existing on the film surface, and lowers the conductivity of the film surface. Therefore, the content of the wax in the synthetic resin film is preferably 3 parts by mass or less based on 100 parts by mass of the synthetic resin.

Surface resistance value: 100 Ω or less If the surface resistance value of the synthetic resin film is larger than 100 Ω, when a drive case is formed using this aluminum alloy material, a method of directly grounding the drive case, If the drive case is grounded by a method such as contacting a highly conductive member,
Sufficient conductivity cannot be obtained at the contact point, and the flow of a minute current into the drive device cannot be sufficiently prevented, so that the memory of the recording medium contained in the drive device is hindered. Therefore, the surface resistance is set to 100Ω or less. In addition, such a surface resistance value can be obtained by the following method.

FIG. 1 is a schematic diagram showing a method of measuring a surface resistance value. As shown in FIG. 1, the tip 2a of a rod 2 made of brass weighing about 40 g is brought into contact with the surface of an aluminum alloy material 1 having a synthetic resin film 1a formed on both surfaces of an aluminum alloy plate 1b. . The tip radius of the rod 2 is 10 mm. Then, the tester 3 and the other end 2b of the rod 2
And connecting the tester 3 and the aluminum alloy plate 1b,
The aluminum alloy plate 1b and the tester 3 are conducted. Thus, the tester 3 can measure the surface resistance value of the synthetic resin film 1a in the aluminum alloy material 1.

The surface roughness Ra of the aluminum alloy plate is 2.
By regulating the surface shape of the aluminum alloy plate on which the concentric annular grooved synthetic resin film of 0 μm or less is formed, adhesion between the aluminum alloy plate and the synthetic resin film, bending of the aluminum alloy material The molding processability such as the property and the overhang property can be further improved, and the material surface can be provided with sharpness. If the surface roughness Ra exceeds 2.0 μm, the rolled roll marks are coarse and the streaks are conspicuous to impair the appearance, which is unsuitable for use in the present invention. Note that the surface roughness Ra is 0.
When the thickness is 1 μm or less, the above-mentioned effects are not sufficiently exhibited, and the glossiness of the material becomes too high, so that the scratches are easily noticeable. Therefore, the surface shape of the aluminum alloy plate is a concentric annular groove having a surface roughness Ra of 0.2 μm or less, and preferably a surface roughness Ra of 0.1 μm to 2.0 μm.

Next, a method for manufacturing such an aluminum alloy material will be described. First, an aluminum alloy having the above-described composition is melted and made into an ingot by continuous casting. Then, for example, a homogenization treatment is performed at a temperature of 500 ° C. for 8 hours. Next, the ingot subjected to the homogenization treatment is subjected to hot rolling or hot rolling and cold rolling to be rolled to a desired thickness. Thereafter, intermediate annealing is performed at a temperature of 350 ° C. or more, and final cold rolling is performed at a final rolling reduction of 20 to 90%.

The intermediate annealing is performed prior to final cold rolling in order to obtain appropriate strength characteristics and workability. This is to recrystallize the aluminum alloy sheet by the intermediate annealing, and therefore, the temperature is set to a temperature higher than the recrystallization temperature, preferably higher than 350 ° C.

Further, if the final cold rolling reduction of the aluminum alloy sheet is less than 20%, sufficient strength cannot be obtained.
On the other hand, if the rolling ratio exceeds 90%, the formability such as bending property and overhang property deteriorates. Therefore, the final cold rolling reduction is preferably set to 20 to 90%.

By the final rolling of the final cold rolling, a concentric annular groove pattern having a surface roughness Ra of 0.1 to 2.0 μm or a surface roughness Ra of 2 μm or less of the aluminum alloy plate to be formed is formed. In the finishing step of the final cold rolling, such a surface shape is formed as a regular pattern by a grinding roll or a sand shot roll (shot dull roll) or a laser beam usually performed by a grindstone, for example, an outer diameter of 200 μm and a surface roughness. Can be formed by performing rolling using a rolling roll (laser dull roll) provided with a concentric annular regular groove of 2 μm or less.

Thereafter, if necessary, a stabilization treatment and a pre-coating treatment before forming a synthetic resin on the aluminum alloy plate are performed at a temperature of 250 ° C. or less. In this stabilization treatment, if the temperature exceeds 250 ° C., the strength of the aluminum alloy sheet tends to decrease, so the heat treatment temperature is preferably set to 250 ° C. or less. If the heat treatment temperature is lower than 150 ° C., the strength required for the present invention may not be stably obtained. Therefore, it is more preferable to carry out the stabilization treatment at a temperature of 150 to 250 ° C.

The pre-coating treatment may be, for example, an undercoating treatment containing chromium ions such as a phosphoric acid chromate treatment (Cr amount of 5 to 40 mg / m ² ) or a coating type chromate treatment, or a zirconium ion, a titanium ion or a manganese ion. A base treatment film containing ions and the like can be formed. Thereafter, a synthetic resin film having a thickness of 20 μm or less is formed using a synthetic resin paint having a conductive substance.

As a result, the surface of the aluminum alloy plate after the final cold rolling has an appropriate surface roughness Ra, the adhesion of the synthetic resin film formed thereafter to the aluminum alloy plate is excellent, and the recording medium drive case is formed. The synthetic resin film is hardly peeled off at the time of molding at the time of forming, and the surface can be provided with sharpness. Further, by performing the intermediate annealing, the final cold rolling, and the stabilizing treatment under optimum conditions, it is possible to obtain the strength characteristics, the bending property (90 ° -0R bending) and the overhang property as the recording medium drive case.

Further, by performing a pre-coating treatment and forming an undercoating film, the adhesion between the aluminum alloy plate and the synthetic resin film is improved, and the corrosion resistance is further improved. Also,
It is likely to occur due to sliding between the aluminum alloy material and the press mold during press forming, and sliding with parts such as computer-related equipment when the drive case device made of aluminum alloy is attached to or detached from the computer-related equipment. It is possible to suppress the peeling of the synthetic resin film and the generation of the peeled product.

[0053]

EXAMPLES Examples of the present invention will be described below in comparison with comparative examples that fall outside the scope of the present invention.

First Example An aluminum alloy having the composition shown in Table 1 below was melted by a conventional method and cast into an ingot by continuous casting. Next, the ingot was subjected to a homogenization treatment at a temperature of 500 ° C. for 8 hours.
Hot rolling was performed to obtain a plate having a thickness of 3.5 mm. Next, 4
After the intermediate annealing at a temperature of 20 ° C., the sheet thickness is 0.8 mm
, And a stabilization treatment was performed at a temperature of 240 ° C. For some of the materials, finish rolling was performed using shot dull and radar dull rolls in the final pass in the final cold rolling to obtain sheet materials having different surface conditions.

Using this plate material, the tensile performance of the aluminum alloy plate before the coating of the synthetic resin was measured with a JIS No. 5 test piece in order to compare the tensile performance with the test material (the aluminum alloy material after forming the synthetic resin film). did.

Next, both surfaces of the prepared plate material were subjected to a phosphoric acid chromate treatment (Cr content: 20 mg / m ² ), and then synthesized using a synthetic resin-based paint containing various conductive materials while changing the film thickness. A test material on which a resin film was formed was obtained. The manufacturing conditions, tensile performance and surface condition of the test material are shown in Tables 2 and 3 below. The surface roughness Ra was measured using a surface roughness measuring device (surface roughness measuring device; Surfcoder SE-SO-D; manufactured by Kosaka Laboratory Co., Ltd.). The thickness of the synthetic resin film is determined by using a test piece of a predetermined size, peeling the film with fuming HNO ₃ or the like, and calculating the film mass from the difference in mass before and after peeling.
Thereafter, the film thickness was calculated from the film mass density.

[0057]

[Table 1]

[0058]

[Table 2]

[0059]

[Table 3]

In Tables 2 and 3, the normal condition shown in the surface condition is a grinding wheel polishing roll, the S / D is a shot dull roll, the R / D is a laser dull roll, and the finishing in the final pass of the final cold rolling is performed. Shows the type of rolling roll used for rolling. In addition, the content of the conductive substance indicates a part by mass in which the conductive substance is contained with respect to 100 parts by mass of the synthetic resin. The same applies to the following tables.

The following measurements were respectively performed to evaluate the material properties of the obtained test materials. The measurement results and evaluation are shown in Tables 4 and 5 below.

The tensile strength of the test material was measured for tensile strength, proof stress and elongation using a JIS No. 5 test piece in the same manner as for the aluminum alloy plate before the formation of the synthetic film.

For the conductivity of the test material, the surface resistance of the test material surface was measured by the method described above.

As for the slidability (scratch resistance), the surface of the test material having a diameter of 4 mm was measured using a Bowden adhesion slide tester.
A hard sphere of 23 (mm) was brought into contact, and sliding was repeated at the same position at a speed of 4 mm / sec with a load of 200 g. Then, the number of slides at which a flaw reaching the aluminum alloy plate on which the synthetic resin film was formed on the surface of the test material was measured. When the number of times of sliding exceeds 20 times and the sliding property is extremely good, ◎ is given. When the number of times of sliding exceeds 10 times and the sliding property is good, ○ is given. Ten times were evaluated as Δ, and ones with one or less sliding times were evaluated as x.

Regarding the fingerprint resistance, a fingertip is attached to the surface of the test material by pressing a fingertip of a bare hand, a fingerprint attached portion and a non-attached portion are measured with a color difference meter, and a color difference (ΔE) is obtained according to JIS Z 8730. Was. If the color difference value is smaller than 0.5 and the fingerprint is hardly noticeable, the result is ○.
When the fingerprint was slightly conspicuous between 5 and 1.5, the evaluation was Δ, and when the color difference value exceeded 1.5, the fingerprint was evaluated as X.

Regarding corrosion resistance, JIS Z 2371
The presence or absence of corrosion after the 96-hour salt water fountain test was examined. Then, the rating No. ◎ above 9.8, rating No.上 の above 9.5, rating No. 9 to 9.5, and rating No. Those less than 9 were evaluated as x.

Regarding the state of film peeling and bending workability,
Perform a 90 ° -0R bending test with the thickness of the test material as the bending radius, observe the bent portion with a stereoscopic microscope with a magnification of 50 to 200 times to check the peeling state of the synthetic resin film, The bending workability was evaluated from the state. Regarding the evaluation of the state of film peeling, a mark without peeling was evaluated as ○, a film with slight film peeling was evaluated as △, and a film with severe peeling was evaluated as ×. In addition, as for the evaluation of the bending workability, those without cracks were evaluated as ○, those with minute cracks as Δ, and those with large cracks as X.

[0068]

[Table 4]

[0069]

[Table 5]

Since Examples 1 to 23 were within the scope of the present invention, there was almost no change in mechanical properties before and after the application of the synthetic resin paint, and all exhibited good tensile performance. In addition, the slidability, fingerprint resistance, corrosion resistance and the like were also excellent.

In Comparative Example 1, since the synthetic resin film was not formed, the surface resistance value was 1 Ω, indicating excellent conductivity. However, the sliding property, fingerprint resistance, corrosion resistance, etc. were poor, and the desired properties were not obtained. Could not be obtained.

In Comparative Example 2, since the formed synthetic resin film had no conductive substance, the surface resistance was Δ.

In Comparative Example 3, the content of the conductive substance in the formed synthetic resin film was less than the lower limit of the present invention, and in Comparative Example 5, the film thickness of the synthetic resin film was lower than the upper limit of the present invention. Therefore, in both cases, the surface resistance was large and the conductivity was poor.

In Comparative Example 4, since the content of the conductive substance in the synthetic resin film exceeded the upper limit of the range of the present invention, good conductivity was obtained, but the conductive substance was hardly fixed to the synthetic resin film. As a result, the conductive material is easily dropped, so that the slidability is inferior and the scratch is easily generated. Also,
The conductive material was also missing in the bent part. Further, the ratio of the synthetic resin was reduced due to the conductive material of the synthetic resin film, and the effect of suppressing the adhesion of fingerprints was reduced, and the fingerprints became more noticeable.

In Comparative Example 6, since the Mg content of the aluminum alloy plate was less than the lower limit of the range of the present invention, sufficient mechanical properties could not be obtained after the stabilization treatment, and the tensile test performance after coating was deteriorated. However, the strength was insufficient for use as a recording medium drive case material.

Second Embodiment The alloy No. shown in Table 1 used in the first embodiment was used. An aluminum alloy having the composition shown in A is melted by a conventional method and continuously cast to form an ingot. After the homogenization treatment, hot rolling and intermediate annealing in the same steps as in the first embodiment, the final cold Rolled and then stabilized at 200 to 250 ° C to obtain a thickness of 0.8m
m plate material was formed. Note that only the test material of Example 34 was not subjected to the stabilization processing. In Examples 24 to 33, after a stabilization treatment, and in Example 34, after final cold rolling, a test material having a synthetic resin film formed thereon was prepared in the same manner as in the first example. As the synthetic resin film, a polyester resin paint containing 50 parts by mass of Ni as a conductive substance with respect to 100 parts by mass of the synthetic resin is used.
m was applied to an aluminum alloy plate to form a synthetic resin film on both sides of the aluminum alloy plate. Table 6 below
The production conditions of this test material are shown below. The prepared test materials were evaluated for tensile performance, conductivity, slidability, and the like in the same manner as in the first example. Regarding the surface quality, ○ indicates that the surface was good, and X indicates that the surface roughness was large. The results are shown in Table 7 below.

[0077]

[Table 6]

[0078]

[Table 7]

In Examples 24 to 34, the composition of the aluminum alloy plate, the thickness of the synthetic resin film, etc. were within the scope of the present invention, and the manufacturing conditions were within the preferred ranges of the present invention. Even after the formation of the resin film, there is almost no change in its mechanical properties compared to before the formation,
All exhibited good tensile performance. In addition, all of the test materials had extremely small surface resistance values and had good conductivity. In addition, extremely good results were obtained in terms of slidability, fingerprint resistance, corrosion resistance, paint releasability, and bending workability.

In Example 35, excellent slidability, fingerprint resistance,
Despite showing corrosion resistance, film peelability and bending workability, since the surface roughness Ra is less than the preferred range of the present invention, the roll is fine, the glossiness of the test material surface is increased, and the surface is slightly scratched. Was.

In Comparative Examples 7 to 11, any one of the manufacturing conditions is out of the preferred range of the present invention, and therefore any of the properties required as a material used as a recording medium drive case is inferior. It was unsuitable as a material.

In Comparative Example 7, since the stabilization temperature exceeded the preferred range of the present invention, the tensile strength and the proof stress were less than the range of the present invention, and the strength was insufficient.

In Comparative Example 8, since the final cold rolling reduction was less than the preferred range of the present invention, the tensile strength exceeded the upper limit of the present invention, and the strength as a recording medium drive case material was insufficient.

In Comparative Example 9, since the final cold rolling ratio exceeds the preferred range of the present invention, the tensile strength exceeds the upper limit of the range of the present invention, and the strength of the resin-coated aluminum alloy material becomes too high, resulting in poor bending workability. Deteriorated.

Comparative Example 10 shows that the aluminum alloy plate
Since the content was less than the lower limit of the range of the present invention, sufficient strength could not be obtained after the stabilizing heat treatment.

In Comparative Example 11, since the thickness of the synthetic resin film containing a conductive substance exceeded the range of the present invention, the surface resistance of the material exceeded 100 Ω, and the conductivity became insufficient.

Third Embodiment Using a stabilizing material for an aluminum alloy plate prepared by the same composition and manufacturing method as in the first embodiment used in the first embodiment, a synthetic resin paint was applied to this aluminum alloy plate. Prior to coating, a base treatment shown in Table 8 below was performed. After that, the aluminum alloy plate
A test material in which a synthetic resin film is formed by applying a polyester synthetic resin paint containing 50 parts by mass of a conductive substance Ni to 100 parts by mass of a synthetic resin made of polyester so that the coating thickness becomes 3 μm. It was created. Then, with respect to these test materials, the conductivity, slidability, fingerprint resistance, film peeling state and bending workability were measured in the same manner as in the first example. The evaluation results are shown in Table 9 below.
Shown in

[0088]

[Table 8]

[0089]

[Table 9]

As shown in Table 9, Examples 36 to 40
Formed an undercoating film containing a metal ion within the preferred range of the present invention, so that the sliding property and corrosion resistance were further improved in any of the examples as compared with Example 1.

Fourth Embodiment Using a stabilizing material for an aluminum alloy plate prepared by the same composition and manufacturing method as in the first embodiment used in the first embodiment, a synthetic resin paint was applied to this aluminum alloy plate. Prior to coating, a chromium ion-containing film (phosphate chromate treatment) was subjected to a base treatment to form a base film so that Cr became 20 mg / cm ² . Then, a polyester-based synthetic resin paint containing 50 parts by mass of a conductive material Ni with respect to 100 parts by mass of a synthetic resin made of polyester is coated on the aluminum alloy plate subjected to the base treatment so that the coating thickness becomes 3 μm. A test material coated and formed with a synthetic resin film was prepared. Then, the material properties of the test material were measured in the same manner as in the first example. In addition, after measuring the slidability, the appearance of the hard sphere was observed to determine whether or not the hard sphere was stained by wax adhesion. When no dirt was observed on the hard sphere due to the adhesion of the wax, x was given, and when dirt was found, x was given. The evaluation is shown in Table 10 below.

[0092]

[Table 10]

In Table 10, the content of the wax in the film indicates parts by mass of the wax contained with respect to 100 parts by mass of the synthetic resin in the synthetic resin paint.

In Examples 41 to 47, the amount of the wax contained in the synthetic resin paint was 3 parts by mass or less based on 100 parts by mass of the synthetic resin, and the amount of the wax contained in the synthetic resin paint was within the preferable range of the present invention. Conductivity, sliding property, fingerprint resistance,
The corrosion resistance, film peeling state, and bending workability were all good, and especially the slidability was further improved, and no stain was observed on the hard sphere after the sliding test.

In Comparative Examples 12 and 13, since the wax content was more than 3 parts by mass with respect to 100 parts by mass of the synthetic resin in the synthetic resin paint, and exceeded the preferred range of the present invention, the surface resistance exceeded the range of the present invention. . In addition, stains due to wax adhesion after the sliding test were observed. In addition, the conductivity and fingerprint resistance decreased due to the wax unevenly distributed on the surface of the synthetic resin film.

Fifth Embodiment A stabilizing material for an aluminum alloy plate prepared by the same composition and manufacturing method as in the first embodiment used in the first embodiment is used, and a synthetic resin paint is applied to this aluminum alloy plate. Prior to coating, a chromium ion-containing film (phosphate chromate treatment) was subjected to a base treatment to form a base film so that Cr became 20 mg / cm ² . Then, a polyester-based synthetic resin paint containing 50 parts by mass of a conductive material Ni with respect to 100 parts by mass of a synthetic resin made of polyester is coated on the aluminum alloy plate subjected to the base treatment so that the coating thickness becomes 3 μm. A test material coated and formed with a synthetic resin film was prepared. Note that Ni, which is a conductive substance, was in the form of a scale, and its thickness and major axis were variously transformed into the shapes shown in Table 11 below. Using these test materials, the material properties of the test materials were measured in the same manner as in Example 1. The evaluation is also shown in Table 11 below.

[0097]

[Table 11]

In Examples 48 and 49, the thickness of the flaky Ni used as the conductive material was 3 μm or less, the maximum value of the major axis was 100 μm or less, and the average value of the major axis was 10 to 3 μm.
0 μm, which is within the preferred range of the present invention,
The dispersion state of the scale-like Ni in the synthetic resin paint became extremely good, and therefore, even in the synthetic resin film, Ni was uniformly dispersed and exhibited excellent conductivity.

In Example 50, the average value of the major axis of the scaly Ni was slightly larger at 40 μm. In Example 51, the thickness of the scaly Ni was slightly larger at 4 μm, and in Example 52, the maximum value of the major axis was 150 μm. The average value of the major axis is slightly larger at 50 μm,
Since any of the test materials of Examples 50 to 52 is out of the preferable range of the present invention, the dispersibility of flaky Ni in the synthetic resin paint is reduced, and Ni, which is a conductive material partially in the synthetic resin film, is reduced. Or the contact effect was slightly lowered due to the concentration of Ni at the interface between the synthetic resin film and the aluminum alloy plate on which the film was formed, so that the conductivity was slightly lowered as compared with Examples 49 and 50. did.

[0100]

As described in detail above, according to the present invention, since the aluminum alloy plate contains 2.0 to 6.0% by mass of Mg, the aluminum alloy plate has high strength and contains a predetermined amount of a conductive substance. Since the resin film is formed with a thickness of 20 μm or less, it has excellent corrosion resistance, fingerprint resistance, slidability and corrosion resistance, and also has excellent conductivity. Thereby, the ground can be easily taken, the surface is hardly scratched, the fingerprint is hardly noticeable, and the weight is light, so that a resin-coated aluminum alloy material suitable for a storage medium drive case can be obtained.

[Brief description of the drawings]

FIG. 1 is a schematic view showing a method for measuring a surface resistance value according to the present invention.

[Explanation of symbols]

 1; aluminum alloy material 2a; tip 2b; other end 3: tester

Continued on the front page (72) Inventor Nobuo Hattori 15 Kinuigaoka, Moka-shi, Tochigi Prefecture Kobe Steel Moka Works F-term (reference) 4D075 CA22 DA06 DB07 DB31 DC19 EC54 EC60

Claims (2)

[Claims] 1. An aluminum alloy plate containing Mg: 2.0 to 6.0% by mass, and a synthetic resin film formed on the surface with a thickness of 20 μm or less, wherein the synthetic resin film is 10 to 200 parts by mass of a conductive material is contained with respect to 100 parts by mass of the synthetic resin, and the surface resistance is 10
0Ω or less and the total tensile strength is 210 to 4
A resin-coated aluminum alloy material for a storage medium drive case, which has a strength of 10 MPa and a proof stress of 150 to 370 MPa. 2. The resin-coated aluminum alloy material for a storage medium drive case according to claim 1, wherein the aluminum alloy plate has concentric annular grooves having a surface roughness Ra of 2 μm or less on the surface.