JPH1064223A - Aluminum or aluminum alloy plate material for disk shutter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide aluminum or aluminum alloy sheet material for disk shutter that has improved scratch resistance property, bending machining property, solvent resistance property, and adhesion property with UV ink and can prevent bun from being generated on the end face of a disk shutter after machining the disk shutter. SOLUTION: In aluminum or aluminum alloy sheet material for disk shutter used for opening or closing a window part for recording head being provided at a case for accommodating a disk for recording, chromate coating is formed on the surface of the aluminum or aluminum alloy plate and polyester resin coating is formed on the chromate coating. The thickness of the polyester resin coating is preferably 20μm or less and inner wax content in the polyester resin coating is preferably 3wt.% or less.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an aluminum or aluminum alloy plate for a disk shutter which is a material for a shutter provided in a case of a magnetic disk such as a flexible (floppy) disk or the like, an MO disk and an optical disk such as a mini disk.

[0002]

2. Description of the Related Art A magnetic disk such as a flexible disk and a hard disk, an optical disk such as an MO disk, and a mini disk contain a magnetic disk medium or an optical disk medium for storing information in a case. At the time of writing or reading information, a magnetic head or an optical head is inserted into the case to read or write the magnetic disk medium or the optical disk medium. Accordingly, these disk cases are provided with an opening (window) as a window for inserting a magnetic head or an optical head, and a shutter for opening and closing the window.

The shutter is a plate member having a U-shaped cross section. The shutter is guided by a guide groove provided in the case in a state where the case is sandwiched between a pair of surfaces, and slides in parallel with the surface. Open and close the window of the case. Heretofore, as a plate material for a disk shutter, there has been one manufactured using a synthetic resin such as stainless steel, polystyrene, and ABS (acrylonitrile-butadiene-styrene copolymer).

[0004] However, the stainless steel shutter is heavy and has a drawback that a fingerprint is easily attached when the surface is touched with a finger. Also, polystyrene or A
A material made of a synthetic resin such as BS has a drawback that it is easily charged, and is harmful to the magnetic surface because dust and dust easily adhere thereto. Further, a disk shutter is usually
In order to display the manufacturer name and product type, U
The printing process is performed by the V-curing method, but since the synthetic resin shutter does not easily adhere to the UV ink, a surface modification process such as corona discharge is performed as a pre-process to improve the adhesion of the UV ink. There is a need. As a result, there is a problem that the manufacturing cost is increased.

A function required of the disk shutter is to open and close when necessary and to protect the magnetic surface. Further, since the shutter slides while being guided on the case, it needs to be lightweight and rigid.

In view of the above, a disk shutter plate made of aluminum or an aluminum alloy has recently been proposed as a disk shutter plate material that can solve the above-mentioned problems and satisfy the required functions. Further, since the shutter is a sliding member, harmful shavings are generated on the disk when the case is damaged by the opening / closing operation. Therefore, in order to prevent this, a disk shutter in which a metal core body is coated with a coating layer made of a synthetic resin having good slipperiness is disclosed (Japanese Patent Application Laid-Open No. Hei 3-73479). Further, a shutter in which the surface of an aluminum alloy material is coated with an epoxy acrylic or ethylene acrylic synthetic resin has been proposed (JP-A-6-346).
178 publication).

[0007] In addition, a disk shutter in which a surface hardening coating is provided on the surface of an aluminum alloy material for improving abrasion resistance and preventing plastic deformation is also known (JP-A-6-68638). Further, there has been proposed a disk cartridge provided with an anodized film on the surface of an aluminum or aluminum alloy plate in order to improve the surface finish by coloring (JP-A-6-111516 and JP-A-6-162710). ).

[0008]

However, these conventional disk shutters have the following problems. First, when the surface of an aluminum alloy material is coated with a synthetic resin such as an epoxy-based or epoxy-acrylic-based resin, the film of the synthetic resin is soft, so that the surface is easily scratched and harmful dust is likely to be generated on the magnetic surface.

When the surface of an aluminum alloy material is coated with an ethylene acrylic synthetic resin, the film is easily eluted in an ultrasonic cleaning process using 1,1,1-trichloromethane after punching and pressing. Then, the punched samples are welded to each other by this coating. Also, the adhesion of the printed UV ink is insufficient.

Further, when the surface of the aluminum alloy material is subjected to anodizing treatment, when the film is bent to form a U-shape, cracks are easily formed in the coating at a 90 ° bending portion. Due to the propagation of cracks from the coating to the base material, it is easy to break at 90 ° bending portions. In addition, there is also a problem that the surface of the anodized surface is liable to cause interference colors and the appearance is deteriorated. Furthermore,
When performing anodizing treatment on the surface of aluminum alloy material,
Since a stable current supply and a sufficient processing time are required, the manufacturing cost of the product increases.

The present invention has been made in view of the above-mentioned problems, and has been made in consideration of scratch resistance, bending workability, solvent resistance and U.S.C.
Provided is an aluminum or aluminum alloy plate material for a disk shutter which has good adhesion to V ink and preferably can prevent burrs from being generated on an end surface of the disk shutter after processing the disk shutter. With the goal.

[0012]

An aluminum or aluminum alloy plate for a disk shutter according to the present invention is an aluminum for a disk shutter used for a shutter for opening and closing a recording head window provided in a case for accommodating a recording disk. Alternatively, in the aluminum alloy plate material, a chromate film is formed on a surface of the aluminum or aluminum alloy plate, and a polyester resin film is formed on the chromate film.

The thickness of the polyester resin film is 20 μm.
m or less, and the polyester resin film desirably contains 3% by weight or less of an inner wax based on the total weight of the polyester resin film. The coefficient of kinetic friction of the polyester resin film is 0.05 to 0.20.
It is preferred that Further, the chromate film is formed by a coating type chromate treatment or a phosphoric acid chromate treatment, and the amount of the coating is preferably 5 to 30 (mg / m ² ) in terms of Cr.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the present invention, a polyester resin film is formed on the outermost surface of an aluminum or aluminum alloy plate for a disk shutter. Since this polyester resin film is harder than a film made of an epoxy-based or epoxy-acrylic synthetic resin, it is possible to make the surface of the disk shutter hard to scratch. Further, the chromate film formed between the aluminum alloy plate and the polyester resin film has an action of increasing the adhesion between the aluminum or aluminum alloy material and the polyester resin film. Therefore, harmful dust is less likely to be generated on the magnetic surface.

[0015] The polyester resin film has a property of being superior in solvent resistance as compared with a film coated with an ethylene acrylic synthetic resin, and further has a chromate film as described above. As a result, since the adhesiveness with aluminum or an aluminum alloy material is excellent, even when ultrasonic cleaning is performed using 1,1,1-trichloromethane, the film is not eluted, and Welding can be prevented. Furthermore,
Since the polyester resin film has excellent adhesion to UV ink, the UV for displaying the manufacturer name and quality printed on the disk shutter surface by the UV curing method is used.
There is no problem that ink is peeled off.

Further, the polyester resin film is excellent in stretchability of the film itself and has excellent adhesion to aluminum or aluminum alloy material due to the presence of the chromate film. Also, cracks are less likely to occur in the bent portion.

The inventors of the present invention configure the aluminum or aluminum alloy plate for a disk shutter as described above, and further define the film thickness, the contained components and the kinetic friction coefficient of the polyester resin film, the amount of the chromate film deposited, and the like. As a result, it has been found that the characteristics as a disk shutter can be further improved.

Hereinafter, the aluminum or aluminum alloy plate for a disk shutter according to the present invention will be further described.

The thickness of the polyester resin film: 20 μm or less
When the thickness of the lower polyester resin film exceeds 20 μm, the raw material cost increases, and the wear powder of the aluminum or aluminum alloy plate generated at the time of punching press processing, the coating resin component, and the processing press oil are mixed to form a sludge. In this case, a problem occurs that the clearance of the mold is clogged. Therefore, the thickness of the polyester resin film is 20 μm.
m or less.

Inner wack in polyester resin film
When the inner wax is added to the material of the polyester resin film, the lubricity of the surface of the polyester resin film is improved, and the effect of preventing the formation of scratches on the disk shutter surface is enhanced. When the content of the inner wax exceeds 3% by weight based on the total weight of the polyester resin film, the lubricity of the polyester resin film material, that is, the slipperiness of the surface-treated film (material) surface is increased. Therefore, at the time of press working, the amount of material flowing through the die is excessively increased, which causes burrs to occur on the end face of the processed disk shutter. Also, if the polyester resin film contains a large amount of inner wax, the wettability of the film surface is reduced, and if the content exceeds 3% by weight, the UV
The adhesion of the ink is reduced. Therefore, when the inner wax is added to the polyester resin film, its content is 3% by weight based on the total weight of the polyester resin film.
It is preferable to set the following.

Dynamic friction coefficient of polyester resin film:
The coefficient of kinetic friction of the 05 to 0.20 polyester resin film is affected by the lubricity of the polyester resin film material during film formation. That is,
As the lubricity of the polyester resin film material increases, the coefficient of dynamic friction of the polyester resin film decreases. When the kinetic friction coefficient of the polyester resin film is less than 0.05, the lubricating property of the polyester resin film material at the time of film formation is high, so that burrs are generated on the end surface of the processed disk shutter during the press working as described above. Cause you to On the other hand, when the kinetic friction coefficient of the polyester resin film exceeds 0.20, the lubricity of the surface of the polyester resin film is reduced, and the disk shutter surface is apt to be scratched. Therefore, it is preferable that the dynamic friction coefficient of the polyester resin film is 0.05 to 0.20.

Amount of chromate film applied (Cr equivalent value):
5 to 30 (mg / m ² ) In the present invention, a chromate film is formed on the surface of an aluminum or aluminum alloy plate by a coating type chromate treatment or a phosphoric acid chromate treatment, and the amount of the chromate film to be applied is regulated. Is preferred. As another method of forming a chromate film, there is a chromate chromate treatment. In the present invention, in consideration of the properties and productivity of an aluminum or aluminum alloy plate, a chromate treatment is performed by a coating type chromate treatment or a phosphoric acid chromate treatment. Preferably, a film is formed. If the amount of the chromate film deposited on the surface of the aluminum or aluminum alloy plate is less than 5 (mg / m ² ) in terms of Cr, the chromate film on the surface of the aluminum or aluminum alloy plate becomes non-uniform. The adhesion between the polyester resin film formed on the substrate and the aluminum or aluminum alloy plate is reduced. On the other hand, if the coating amount of the chromate film exceeds 30 (mg / m ² ), cracks are likely to occur when the aluminum or aluminum alloy plate is subjected to 90 ° bending, and the bending workability is reduced. Accordingly, the amount of the chromate film deposited on the surface of the aluminum or aluminum alloy plate is 5 in terms of Cr.
It is preferably from 30 to 30 (mg / m ² ).

[0023]

EXAMPLES Examples of the present invention will be described below in comparison with comparative examples. First, a method for manufacturing an aluminum alloy sheet according to an embodiment of the present invention will be described. As an aluminum alloy plate, a plate material of 5182-H19 (plate thickness: 0.
185 mm), the surface of this aluminum alloy plate was alkali-degreased, washed with water and dried, and then a chromate film was formed as a first layer on the surface by phosphoric acid chromate treatment or coating type chromate treatment. Thereafter, the plate material was immersed in a predetermined treatment bath and dried to form a polyester resin as a second layer on the chromate film.

As a comparative example, various resin films and the like were formed on the same aluminum alloy plate as in the example without forming the first layer, and after forming a phosphate chromate film as the first layer, An epoxyalkyl resin was formed thereon as the second layer, and the like was prepared.

Next, regarding the various aluminum alloy sheets thus manufactured, the film hardness and the kinetic friction coefficient of the surface were measured, and the scratch resistance, bending workability,
The solvent resistance and the adhesion to the UV ink were evaluated. These measurement methods and evaluation methods are described below.

The film hardness was determined by a pencil hardness test according to JIS K5400. The coefficient of kinetic friction is 3/16 inch using steel balls.
The load was set to 200 gf and the sliding speed was set to 4 mm / sec.
The scratch resistance was evaluated by observing the appearance of the sliding portion of the test plate whose dynamic friction coefficient was measured. In addition, as the evaluation criteria for the scratch resistance, those in which no flaw was generated on the film surface were evaluated as ○, those in which some flaws occurred were evaluated as Δ,
When the flaw reached the aluminum alloy plate as the base material, it was evaluated as x.

The bending property was evaluated by subjecting the test material to 90 ° bending under the condition of an inner diameter of 0 mm.
The evaluation criteria for the bending workability were as follows: も の when no cracks occurred in the coating, △ when cracks occurred only in the coating, and x when cracks reached the aluminum alloy plate as the substrate. The solvent resistance is determined by immersing the test material in 1,1,1-trichloroethane boiled for 6 minutes, ultrasonically oscillating the solvent, and measuring the amount of decrease in the film weight after immersion as the amount of film elution. It was evaluated by:

Further, the adhesion of the UV ink was determined by applying a UV ink (RIG BLACK No. 10; manufactured by Seiko Advance Co., Ltd.) to the surface of the test material. After screen printing using a 270 silk screen, UV curing was performed by irradiating with a UV irradiation device (manufactured by Eye Graphic Co., Ltd.) at an intensity of 120 W / cm ² for 5 seconds. Then, a cross cut was made in the printed portion, a pressure-sensitive adhesive tape was adhered to the portion, and a peeling test was performed. The evaluation criteria for the adhesiveness of the UV ink were as follows: ○: no ink was peeled off; ○: 1 mm or less of the ink around the cross cut from the cross cut area; The sample that reached from the position to a position longer than 1 mm was evaluated as x. First of these Examples and Comparative Examples
Tables 1 and 2 below show the coating composition of the layer and the second layer, the amount applied, and the amount of the inner wax added to the second layer, and the measurement results and evaluation results are shown in Tables 3 and 4 below. Show.

[0029]

[Table 1]

[0030]

[Table 2]

[0031]

[Table 3]

[0032]

[Table 4]

As shown in Tables 1 to 4, the aluminum alloy sheet of this embodiment in which a chromate film is formed on the surface of an aluminum alloy sheet and a polyester resin is formed on this film, has a high film hardness and a high hardness. Since the lubrication was excellent, the scratch resistance was good. In addition, favorable results were also obtained regarding bending workability, solvent resistance, and adhesion to UV ink. In particular, in Example No. 1 to 8
Since the coating amount of the phosphoric acid chromate film, the amount of inner wax added to the polyester resin, and the coefficient of kinetic friction of the film were within the preferred ranges of the present invention, all the evaluation results were excellent.

On the other hand, in Comparative Example No. Since No. 14 does not have a chromate film as the first layer, the adhesion between the aluminum alloy plate as the base material and the polyester resin film is insufficient, and the scratch resistance, bending workability and solvent resistance are not improved. Good results were not obtained. Comparative Example No. Nos. 15 to 17 do not form a chromate film as the first layer and directly form an epoxy-based or epoxy-acrylic resin film on the aluminum alloy plate. Good results were not obtained.

Also, in Comparative Example No. In No. 18, a phosphoric acid chromate film was formed as the first layer, but since the epoxy acrylic resin film was formed on the surface thereof, the scratch resistance was poor. Comparative Example No. In No. 19, since a chromate film was not formed as the first layer and an ethylene acrylic resin film was formed directly on the aluminum alloy plate, the solvent resistance and the adhesion to the UV ink were poor. Comparative Example No. No. 20 does not form a chromate film as the first layer, but forms a film by anodizing on the surface of the aluminum alloy plate, so that the dynamic friction coefficient increases, the scratch resistance decreases, and the bending workability decreases. Became extremely bad.

[0036]

As described in detail above, according to the present invention,
For disk shutters, all of which have good scratch resistance, bending workability, solvent resistance, and adhesion with UV ink, because two layers of predetermined film are formed on the surface of aluminum or aluminum alloy plate An aluminum or aluminum alloy plate can be obtained. In addition to properly defining the film thickness of the polyester resin film, the content when the inner wax is contained, and the coefficient of kinetic friction, and defining the amount of the chromate film to be applied, scratch resistance, bending workability, solvent resistance Further, the adhesiveness with the UV ink is further improved, and furthermore, it is possible to suppress the occurrence of burrs on the end face of the disk shutter after the processing of the disk shutter.

Claims (5)

[Claims] An aluminum or aluminum alloy plate for a disk shutter used for a shutter for opening and closing a recording head window provided in a case for accommodating a recording disk, wherein a chromate film is formed on the surface of the aluminum or aluminum alloy plate. An aluminum or aluminum alloy plate for a disk shutter, wherein a polyester resin film is formed on the chromate film. 2. The film thickness of the polyester resin film is 20.
2. The aluminum or aluminum alloy plate for a disk shutter according to claim 1, wherein the thickness is not more than μm. 3. The polyester resin film contains 3% by weight of inner wax based on the total weight of the polyester resin film.
The aluminum or aluminum alloy plate material for a disk shutter according to claim 1, wherein the aluminum or aluminum alloy plate material contains: 4. The aluminum or aluminum alloy plate for a disk shutter according to claim 1, wherein the dynamic friction coefficient of the polyester resin film is 0.05 to 0.20. 5. The chromate film is formed by a coating-type chromate treatment or a phosphoric acid chromate treatment, and the deposited amount is 5 to 30 (mg / mg) in terms of Cr.
m ² ), the aluminum or aluminum alloy plate material for a disk shutter according to claim 1.