JP3298608B2 - Aluminum alloy coated plate for recording medium cassette shutter excellent in slidability and recording medium cassette shutter made of the aluminum alloy coated plate - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an aluminum alloy coated plate for a recording medium cassette shutter having excellent slidability, more specifically, a cassette containing a micro floppy disk in a case, or a magneto-optical device capable of digital recording and reproduction. Improvement of aluminum alloy coated plate for shutter which opens and closes the head access opening of recording medium cassettes such as disk and optical disk cassettes, especially aluminum alloy coated plate for recording medium cassette shutter which has excellent slidability with the cassette body. And a recording medium cassette shutter made of the aluminum alloy coated plate.

[0002]

2. Description of the Related Art A magnetic disk for a computer, such as a micro floppy disk, or a recording medium cassette in which a recording medium operating by a magnetic, electrostatic, optical, or other operating method is housed in a case made of resin or the like, has a magnetic disk. In order to access recording with a head such as a head, an opening is provided that penetrates a part of the case, and the opening is opened and closed by a shutter that slides left and right. The shutter covers the opening to protect the recording medium when the disk cassette is removed from the device to be used.

Conventionally, as a material for a shutter of a recording medium cassette, a stainless steel plate or a high-molecular synthetic resin plate has been mainly used, and an aluminum alloy plate or an aluminum alloy coated plate which has been anodized has been partially used. However, many stainless steel sheets and anodized aluminum alloy sheets have high surface hardness and large surface roughness.
When the shutter is opened and closed, the plastic case of the cassette body wears and powder is likely to be generated. Also, in the case of aluminum alloy coated plate, if the sliding property of the coating film surface is insufficient, friction with the plastic case of the recording medium cassette main body causes
In many cases, powder was generated due to scratching or peeling of the coating film.

[0004] As a method of improving the slipperiness of the coating film surface,
A method of applying an outer wax such as paraffin to the surface of a coating film and a method of adding an inner wax to the coating film have been proposed.
Paraffin at about 0 ° C, lanolin as melting point 36-42 ° C, microcrystalline as melting point 80 ° C, carnauba wax as melting point 80-86 ° C, melting point 9
For example, polyethylene wax at 9 to 104 ° C is used.

[0005] However, the method of applying the outer wax can considerably improve the slipperiness. However, when the shutter is press-molded, the outer wax easily accumulates in the mold and the frequency of cleaning the press mold increases. There is a disadvantage. The method of adding the inner wax to the coating film can improve the slipperiness by adding a relatively small amount of wax, but the inner wax on the coating film surface softens under the temperature environment when the recording medium cassette is used, so that the shutter slides. There are problems such as a decrease in dynamics, and a drop or adhesion of a wax component to the surface of the recording medium, thereby deteriorating the recording / reproducing function.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned conventional problems in providing slidability of a recording medium cassette shutter made of an aluminum alloy coated plate.
The purpose of this study was to conduct various experiments and studies on the relationship between the composition of the coating film formed on the aluminum alloy plate and the characteristics of the coating film and the slidability. An object of the present invention is to provide an aluminum alloy coated plate for a recording medium cassette shutter excellent in slidability without causing any problem therein, and a recording medium cassette shutter made of the aluminum alloy coated plate.

Further, the inventors have found that even when stored under pressure for a long period of time in a cassette case made of a polyethylene film or the like, the painted surface does not adhere to the film, and the paint surface does not adhere to the polyethylene film or the like. An aluminum alloy coated plate for a recording medium cassette shutter with excellent adhesiveness, in which solid particles are dispersed in the coated film and the surface roughness of the coated film is Ra: 0.2 μm or more and Rp: 1.0 μm or more. Was developed (Japanese Patent Application No. 7-1298).
No. 24), of the aluminum alloy coated plate, a coating film according to the present invention is formed on one surface in contact with the plastic case of the cassette body, and the other surface in contact with the synthetic resin storage case is developed first. When the above-mentioned coating film is formed, the aluminum alloy coated plate for a recording medium cassette shutter excellent in slidability and also excellent in non-adhesion with a storage case and a recording medium comprising the aluminum alloy coated plate A cassette shutter is obtained. It is also an object of the present invention to provide such an aluminum alloy coated plate and a recording medium cassette shutter made of the aluminum alloy coated plate.

[0008]

According to the first aspect of the present invention, there is provided an aluminum alloy coated plate for a recording medium cassette shutter excellent in slidability for achieving the above object. On the board, on one side,
Solid lubricant particles having a melting point of 200 ° C. or more are dispersed, and a coating film having a surface dynamic friction coefficient of 0.03 to 0.20 is formed. On the other surface, solid particles are dispersed and surface roughness is reduced. Ra: 0.2 to 1.0 μm, Rp: 1.0 to 10.0 μm
m is formed.

According to a second aspect of the present invention, there is provided an aluminum alloy coated plate for a recording medium cassette shutter having excellent slidability according to the first aspect, wherein the aluminum alloy plate has a main alloy component of 3.0 to 6.0 weight percent Mg. %.

A recording medium cassette shutter according to a third aspect of the present invention is a recording medium cassette shutter made of an aluminum alloy plate having a coating film formed on both sides, and one side of the recording medium cassette shutter which is in contact with a plastic cassette has a temperature of 200 ° C.
Solid lubricant particles having the above melting point are dispersed, and a coating film having a dynamic friction coefficient of 0.03 to 0.20 on the surface is formed. On the other surface of the cassette in contact with the plastic film storage case, the solid particles are coated. Ra is dispersed and surface roughness is Ra:
A coating film having a thickness of 0.2 to 1.0 μm and an Rp of 1.0 to 10.0 μm is formed.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the present invention, various bake-hardening synthetic resin paints such as acrylic, alkyd, acryl-alkyd, melamine and urethane are used for forming a coating film on an aluminum alloy plate. It is also possible to add a coloring material to these paints if necessary. Prior to coating, it is preferable to perform a chemical conversion treatment such as a phosphoric acid chromate treatment on the surface of the aluminum alloy plate.

The present invention is characterized in that solid lubricant particles are dispersed in a coating film formed on the surface of an aluminum alloy plate, and a specific friction characteristic is imparted to the coating film surface by the dispersion of the solid lubricant particles. Given. As the solid lubricant particles, any of organic compound particles and inorganic compound particles can be used. Preferably, organic compound particles such as tetrafluoroethylene resin powder and silicone resin particles are used. Is adjusted so that the dynamic friction coefficient becomes 0.20 or less. If the kinetic friction coefficient of the coating film surface exceeds 0.20, the effect of improving the slipperiness is not sufficient. When the coefficient of kinetic friction is less than 0.03, when the aluminum alloy coated plate is manufactured by the coil coating method or when the press molding is performed, the slippage due to excessive slippage and the winding flow are likely to occur. 0.03
More preferably, it is regulated to 0.20. 0.03 ~
More preferably, it is regulated to 0.15.

The size of the solid lubricant particles is 1/1 / th of the coating thickness.
It is preferable to use those having a particle size of 2 or less, and when solid lubricant particles having a size exceeding this are used, the solid lubricant particles are not sufficiently captured by the coating film, and the particles easily fall off from the coating film. Become. The thickness of the coating film formed on the aluminum alloy plate is 8 μm or less, preferably 1 to 3 μm. The solid lubricant particles desirably have a melting point of 200 ° C. or higher, and if the melting point is lower than 200 ° C., the solid lubricant particles dispersed in the coating film during baking and curing of the coating film may melt. This may affect the slidability of the coating film surface.

On one side in contact with the plastic case,
Forming the coating film of the present invention excellent in slidability, on the other surface in contact with the storage case, when forming a coating film that provides non-adhesion with the synthetic resin constituting the storage case, especially a polyethylene film, This non-stick coating is also preferably 200 ° C.
It is formed by dispersing the above solid particles having heat resistance. Due to the dispersion of the solid particles, the coating has a surface roughness R
a: 0.2 μm or more, preferably 0.2 to 1.0 μm,
Rp: 1.0 μm or more, preferably 1.0 to 10.0 μm
m is given, and the non-adhesion property with the synthetic resin film becomes good. The thickness of the coating film is 8 μm or less, preferably in the range of 1.5 to 8 μm. As the solid particles, organic compound powders such as tetrafluoroethylene resin powder, crosslinked acrylic resin powder, and melamine resin powder, and inorganic compound powders such as aluminum oxide powder, silica powder, and titanium oxide powder are used.

The center line average roughness (Ra) is obtained using a stylus electric type direct-reading center line average roughness measuring instrument, and is a simple industrial measurement method. As shown, in a roughness curve f (x) obtained from a sectional curve using a high-pass filter having a designated cutoff value, f
A portion of the measurement length L is extracted in the direction of the center line of (x),
The portion of f (x) appearing below the center line of the extracted portion is folded back at the center line. The value Ra obtained by dividing the area of the hatched portion obtained by folding back by the measured length L is expressed in μm units. Also, the center line height (R
As shown in FIG. 1, p) (roughness peak) represents the altitude from the center line of the highest point of the roughness curve f (x) above the center line in μm units.

As the aluminum alloy plate in the present invention, various aluminum alloy plates having the strength and corrosion resistance required for the shutter of the recording medium cassette can be used. An Al-Mg alloy plate, which is excellent in bending formability and has excellent adhesion, color, fingerprint resistance, and slidability by forming a synthetic resin coating film, especially Mg3.0 ~ 6.0% (% by weight, the same applies hereinafter) as a main alloying component, and if necessary, at least one of Mn 1.5% or less, Cr 0.3% or less, Cu 0.5% or less, Ti 0.1% or less A plate material of an aluminum alloy containing is preferably used.

[0017]

Hereinafter, examples of the present invention will be described in comparison with comparative examples. Example 1 Aluminum alloy plate (JIS A 5182 alloy, composition: Mg4.5
%, Mn 0.35%, Cu 0.07%, Cr 0.05%, Zn 0.06
%, Ti 0.08%, residual Al, temper: H36, thickness: 0.185m
m) surface treated with phosphoric acid chromate (T-Cr 20mg / m ² )
After that, the following paint was applied with a bar coater and baked at 250 ° C for 60 s to form a coating film.
The test material was used.

Paint: Daimetalon Coat FS Clear No.729 (urethane resin) manufactured by Dainichi Seika Kogyo Co., Ltd.
Particles having a predetermined amount of 0.3 to 0.7 μm) were added.
Table 1 shows the amount of solid lubricant particles in the paint and the thickness of the coating film in each test material.

The coefficient of kinetic friction of the coating film surface was determined by using a friction coefficient measuring device (slip tester) manufactured by Tester Sangyo Co., Ltd. with a load of 1 kg and a sliding speed of 1 m by a three-point ball method.
/ Min under test conditions. Table 1 shows the evaluation results of the slidability evaluated from the value of the dynamic friction coefficient. As shown in Table 1,
All of the coating surfaces formed on the test materials Nos. 1 to 3 according to the present invention have excellent slidability with a dynamic friction coefficient of 0.20 or less.

[0020]

[Table 1] << Table Note >> Sliding property ◎: Dynamic friction coefficient 0.15 or less ○: Dynamic friction coefficient 0.15 or more 0.20 or less △: Dynamic friction coefficient 0.20 or more 0.25 or less ×: Dynamic friction coefficient 0.25 or more

Comparative Example 1 The same aluminum alloy plate as in Example 1 was coated under the same conditions as in Example 1, and the kinetic friction coefficient of the coating film surface of the obtained aluminum alloy coated plate was determined in the same manner as in Example 1. And the slidability was evaluated. Table 2 shows the addition amount of the fluororesin powder, the coating film thickness, the sliding property evaluation, and Ra of each test material.
Test material No. 7 (conventional material) was similarly coated using Daimetallon Coat FS Clear D manufactured by Dainichi Seika Kogyo Co., Ltd. as a paint. As shown in Table 2, the test materials Nos. 4 and 5 have a small amount of solid lubricant particles added, have a large dynamic friction coefficient, and have poor slidability. Test materials Nos. 6 and 7 do not contain solid lubricant particles, and therefore have a high dynamic friction coefficient and no slidability.

[0022]

[Table 2]

Example 2 The same aluminum alloy plate as in Example 1 was used, and the surface was treated with phosphoric acid chromate (T-Cr content: 20 mg / m ² ). One surface was then treated under the same conditions as in Example 1. After painting, the other side was treated with Daimetalon Co., Ltd.
4526-A (urethane-based resin) as solid particles of fluororesin powder from Kitamura Co., Ltd. (particle size: 1 to 8 μm), cross-linked acrylic resin powder from Soken Chemical Co., Ltd. (particle size: 3 to 10 μm)
Was applied using a paint to which a predetermined amount was added. Table 3 shows the amount of solid particles added to the paint and the thickness of the coating film in each test material.
Shown in

[0024]

[Table 3]

The surface roughness of the coating film was measured using a contact surface roughness measuring instrument under the conditions of a measurement length of 2.5 mm, a cutoff of 0.8 mm, a vertical axis magnification of 5000 times and a horizontal axis magnification of 100 times. Ten points were measured in the direction perpendicular to the rolling direction of the sheet (the sheet width direction).
Next, the polyethylene film of the holder part of the floppy disk holder EDH-213NB manufactured by KOKUYO Co., Ltd. was superimposed on the test material (dimensions: 50 mm × 50 mm) having the coating film in which the solid particles were dispersed, and a load of 500 g was applied. ° C, relative humidity
(RH) After being kept in an atmosphere of 80% for 72 hours and further left at room temperature for 24 hours, the load was removed and the film was pulled in the horizontal direction to evaluate the adhesion state between the coating film and the polyethylene film. For those that could not be easily peeled, the degree of adhesion was evaluated by applying a load with a weight to the end of the polyethylene film and measuring the load at which peeling proceeded.

The maximum and minimum values of the measured values of the surface roughness of the coating film formed on the other surfaces of the test materials Nos.
Table 4 shows the evaluation results of the adhesion between the coating film and the polyethylene film. As shown in Table 4, the other surfaces of the test materials Nos. 1 to 3 had a surface roughness of Ra 0.2 μm or more and Rp 1.0 μm or more, and were coated with a polyethylene film with excellent tackiness. A film was formed. That is, on the aluminum alloy coated plates of test materials Nos. 1 to 3, a coating film with excellent slidability was formed on one surface, and a coating film with excellent non-adhesion with the synthetic resin film was formed on the other surface. You.

[0027]

[Table 4] << Table Note >> Non-adhesiveness with polyethylene film ◎: Not adhered ○: Easily peeled

[0028]

As described above, according to the present invention, there is no problem at the time of molding processing, and when applied as a cassette shutter, a recording medium cassette excellent in slidability with a cassette body made of a plastic case. An aluminum alloy coated plate for a shutter and a recording medium cassette shutter made of the aluminum alloy coated plate are provided.

[Brief description of the drawings]

FIG. 1 Center line average roughness (Ra), center line height (Rp)
It is a figure showing the measuring method of.

──────────────────────────────────────────────────続 き Continuing on the front page (72) Kazuhiro Hanaki 5-11-3, Shimbashi, Minato-ku, Tokyo Inside Sumitomo Light Metal Industries Co., Ltd. (72) Tsukasa Kasuga 5- 11-3, Shimbashi, Minato-ku, Tokyo (56) References JP-A-8-221936 (JP, A) JP-A-4-330683 (JP, A) JP-A 8-104939 (JP, A) JP-A-6-104939 346178 (JP, A) JP-A-5-334839 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G11B 23/03-23/033

Claims (3)

(57) [Claims] 1. An aluminum alloy plate having a coating film formed on both surfaces, wherein solid lubricant particles having a melting point of 200 ° C. or more are dispersed on one surface, and the dynamic friction coefficient of the surface is 0.03 to 0.03.
On the other surface, solid particles are dispersed and the surface roughness is Ra: 0.2 to 1.0 μm.
p: an aluminum alloy coated plate for a recording medium cassette shutter excellent in slidability, wherein a coating film having a thickness of 1.0 to 10.0 μm is formed. 2. The recording medium having excellent slidability according to claim 1, wherein the aluminum alloy plate contains 3.0 to 6.0% by weight of Mg as a main alloy component. Aluminum alloy coated plate for cassette shutter. 3. A recording medium cassette shutter made of an aluminum alloy plate having a coating film formed on both surfaces, wherein one surface in contact with a plastic cassette has a temperature of 200 ° C.
Solid lubricant particles having the above melting point are dispersed, and a coating film having a dynamic friction coefficient of 0.03 to 0.20 on the surface is formed. On the other surface of the cassette in contact with the plastic film storage case, the solid particles are coated. Ra is dispersed and surface roughness is Ra:
A recording medium cassette shutter, wherein a coating film having a thickness of 0.2 to 1.0 μm and an Rp of 1.0 to 10.0 μm is formed.