JPH04281285A - Cover packing assembly for hard disk device and production thereof - Google Patents

Abstract

PURPOSE:To provide the cover packing assembly for a hard disk device having excellent production adaptability, cleanliness and sealability and the process for producing this assembly. CONSTITUTION:This cover packing assembly for the hard disk device is formed by applying a packing to the joint part of the cover for the hard disk device. This packing is formed by curing liquid acrylonitrile/butadiene rubber. An FIPG method is used in the above-mentioned production process.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hard disk drive cover, and more particularly to a hard disk drive cover/packing assembly that integrates a hard disk drive cover and packing.

0002

2. Description of the Related Art A hard disk device is a disk made of aluminum alloy or the like with a magnetic material fixed to it (called a hard disk), which is housed in an airtight container with a gap of about 0.1 to 0.5 μm between the hard disk and the hard disk. In this device, a magnetic head is attached through the magnetic head, and information is recorded and read using the magnetic head. Therefore, if dust is generated in the sealed container or if dust enters from outside, the magnetic surface of the disk or the magnetic head may be destroyed. In order to prevent such inconveniences, an air circulator with a high-performance filter is installed inside the closed container to collect dust from inside and outside to keep the air inside clean. However, in order to prevent the infiltration of dust and the like from the outside, packing is required to block the gap between the cover and the container forming the closed container. Therefore, such packing is required to have cleanliness such that the packing itself does not generate dust, and barrier performance (referred to as sealing performance) to prevent dust from entering from the outside.

[0003] Conventionally, the above-mentioned packing has been made by punching a molded sheet of neoprene rubber, urethane rubber, silicone rubber, NBR rubber, foamed rubber of these rubbers, or foamed rubber of polyolefin such as polyethylene into a predetermined shape.
A punched packing (referred to as a punched packing) or a molded product molded into a predetermined shape (referred to as a molded packing) was used.

[0004] From the viewpoint of workability, these packings are prepared by applying an adhesive to the packing and then pasting a release paper on it, and then peeling off the release paper and pasting it on the cover for the hard disk drive when using the packing. The process is complicated because the adhesive is applied between the hard disk device cover and the hard disk device cover, and the packing is then attached. Another drawback was that it caused dust to be generated.

[0005] Furthermore, since it is difficult and requires skill to accurately attach the above-mentioned packing to a predetermined position at the joint between the hard disk drive cover and the hard disk drive container (referred to as positioning), hard disk drive cover assembly is difficult. Another disadvantage was that the manufacturing cost of the three-dimensional object increased.

[0006]Furthermore, punching packing requires a metal mold and a cutting die for punching, and unusable residual sheets (so-called cut loss) are generated after punching, which increases the cost of manufacturing the packing. At the same time, there is a problem in that the remaining sheets must be disposed of. In addition, molded packing requires a mold for molding, increasing the cost of manufacturing the packing, and also has the disadvantage that dust may be generated inside if deburring is insufficient during molding.

On the other hand, the present inventors proposed applying liquid addition-curing silicone rubber directly to the seam of a hard disk device cover as a packing (Utility Model Application No. 62
-98098), silicone rubber has a moisture permeability coefficient of 50 to 1
00 g·mm/m 2 ·24 hours, which is relatively high, and the sealing property against water vapor is insufficient, which has the drawback of restricting the environment in which the hard disk device can be used.

[0008]

[Problems to be Solved by the Invention] As a result of intensive study to solve the above-mentioned drawbacks, the present inventors applied liquid acrylonitrile butadiene rubber to a predetermined position of a cover for a hard disk drive, and cured it to form a packing. In addition to making it easier to manufacture cover/packing assemblies for hard disk drives and reducing manufacturing costs, it also prevents dust from forming inside the equipment, improving not only the cleanliness of the packing but also the sealing. The inventors have discovered that it is possible to create a cover/packing assembly for a hard disk drive that has excellent properties, and has arrived at the present invention.

[0009] Accordingly, a first object of the present invention is to provide a cover/packing assembly for a hard disk drive that is not only easy to manufacture but also has excellent sealing properties as well as cleanliness. A second object of the present invention is to provide an improved method of manufacturing a cover/packing assembly for a hard disk drive, which has excellent cleanliness and sealing properties.

0010

[Means for Solving the Problems] The above-mentioned objects of the present invention are to provide a cover/packing assembly for a hard disk drive in which packing is applied to the joint portion of the cover for a hard disk drive, wherein the packing is made of liquid acrylonitrile butadiene rubber. This has been achieved by a cover/packing assembly for a hard disk drive and a method for manufacturing the same, which is characterized by being made by curing.

The packing applied to the hard disk drive cover used in the present invention is formed by curing liquid acrylonitrile butadiene rubber. The acrylonitrile butadiene rubber used in the present invention has a composition as described below, and is liquid at room temperature (0 to 30°C). It can be formed into a fixed shape, has fast curing properties, and has good adhesive properties, so by applying it to the seam of the hard disk device cover, it is possible to form a packing that is integrated with the cover. can.

The acrylonitrile butadiene rubber used in the present invention is an acrylonitrile butadiene polymer (viscosity 100,000 to 100,000 poise) having carboxyl groups at both ends and is represented by the following (Chemical formula 1):

[Chemical formula 1] (However, X=1 to 100, Y=0 to 10 and Z=1 to 3
0),

Epoxy polymers having glycidyl groups at both ends, aliphatic or aromatic amines, triphenylphosphine (C6H5)3 as side chain extension and curing agents.
It is a composition containing a curing catalyst such as P, a reinforcing agent or filler such as silica, carbon black, mica, calcium carbonate, alumina, iron oxide, talc, and an antioxidant if necessary.

Specific examples of the above-mentioned epoxy polymers having glycidyl groups at both ends include the following (chemical formulas 1) to (chemical formula 6).
Examples include polymers having the chemical formula (Chemical formula 2) to (Chemical formula 6) which are optionally modified with the polymer (Chemical formula 1).

[Case 2] (However, n=0 to 3)

[Chemical formula 3] (However, n=0-3 and m=0-3)

[C4] (However, n=0 to 3)

[C5]

[C6]

[0015] Specific examples of the curing catalyst such as the aliphatic or aromatic amine include the following compounds (7) to (10).

[C7] (However, n=0 to 5)

[Chemical formula 8]

[Chemical formula 9]

[Chemical formula 10]

The viscosity of the acrylonitrile butadiene rubber composition that can be used in the present invention is set to 1.
It is preferable to adjust the blending amount of the composition so that it falls within the range of 0 to 100,000 poise (value measured by a rotational viscometer at 25° C.).

The hardness after curing of the acrylonitrile butadiene rubber composition that can be used in the present invention is determined by forming the composition integrally on a cover for a hard disk drive as a packing, and then attaching the cover to a container. From the perspective of reducing the stress burden on the cover when attached, the
It is preferable to adjust the blending amount of the above-mentioned curing agent, etc. so that the hardening agent has the following properties (measured based on type A).

The acrylonitrile butadiene rubber used in the present invention can be easily obtained by uniformly mixing certain amounts of each of the above compositions. The acrylonitrile butadiene rubber compounded as described above can be transported by pump, and can be applied onto a hard disk drive cover by ejecting it from a nozzle, for example, and the finished cross-sectional shape in this case is usually semicircular. However, by appropriately adjusting discharge conditions such as the height of the nozzle, it is also possible to form a shape with a flat upper part.

In the present invention, the above-mentioned acrylonitrile butadiene rubber is applied to a predetermined position of a hard disk drive cover by the FIPG method, and the rubber is cured to form a hard disk drive cover/packing assembly.

[0020] FIPG (Forme
The d In Place Gasket method is called a free-forming gasket or an on-site forming gasket, and by combining a coating robot, a transport pump, and a dispenser, liquid acrylonitrile butadiene rubber is supplied by the transport pump and discharged by the dispenser. At the same time, this is a method in which a gasket is formed by coating using a coating robot according to a pre-stored pattern. Therefore, by applying the acrylonitrile butadiene rubber according to a pre-stored pattern using a robot mechanism, it is possible to accurately install the acrylonitrile butadiene rubber at the joint position of the hard disk drive cover.

[0021] A hard disk drive is manufactured by tightening the cover/packing assembly for a hard disk drive having the packing obtained in this manner onto a hard disk container with screws or the like to integrate the hard disk drive. As mentioned above, the stress on the hard disk drive cover is effectively reduced since it is 10 to 60Hs.

[0022] Furthermore, since the packing made of acrylonitrile butadiene rubber has a small moisture permeability coefficient, it has extremely excellent sealing properties against water vapor. In the present invention,
After applying the acrylonitrile butadiene rubber, further cleaning treatments such as water washing, air washing, drying, etc. may be performed as necessary.

[0023]

According to the present invention, there is no need to mold a packing molded product in advance to match the shape of the joint portion of the cover member using a metal mold, or to punch it out from a sheet, so there is no need for a metal mold or a punching die. In addition, since the cover is directly molded and bonded onto the cover, there is no need for an adhesion process between the cover and the molded or punched product, which is performed in the case of molded or punched products. Furthermore, since the packing shape is directly applied and molded onto the cover, no burrs are generated, and there is no cut loss in punched products. Furthermore, since acrylonitrile butadiene rubber has excellent sealing properties against water vapor and the like, it has the effect of expanding the environments in which it can be used in laptop computers and the like equipped with hard disk drives.

[0024]

EXAMPLES The present invention will be explained in more detail with reference to Examples below, but the present invention is not limited thereto. Example 1. Acrylonitrile butadiene of Composition Example 1 shown in Table 1 below is applied to the aluminum top cover, the surface of which has been electrodeposited with epoxy resin, using a coating robot (manufactured by Yaskawa Electric Co., Ltd.) according to a pre-stored pattern. Rubber was applied.

[0025]

[Table 1] Composition Example 1; ────────────────────────
─────────── Acrylonitrile butadiene polymer with carboxyl groups at both ends: 100 parts by weight
Hycar CTB 2000 ×162
Manufactured by Ube Industries, Ltd. (Product name) Modified epoxy polymer:
12.3 parts by weight
TSR-930 Manufactured by Dainippon Ink and Chemicals Co., Ltd.
Product name) Curing catalyst:

0.74 parts by weight (2,4,6
-tris(dimethylaminomethyl)phenol)
Ketjen EC600JD:
3.0 parts by weight (product name manufactured by Ketjenblack International Co., Ltd.) Antioxidant:

0.5 parts by weight
(2,6-di-t-butyl-4-methylphenol)
────────────────────────
──────────

[0026] The coating conditions are: nozzle inner diameter: 1.3 mmφ, supply pump pressure: 1.8 kgf/
m2, coating speed: 200mm/min, nozzle height (
(from the cover surface): 1.5 mm, and after coating, it was placed in a hot air dryer at 150°C to harden, and then cooled to form a semicircular cross section with a height of 1.0 mm and a width of 1.5 mm. A cover and packing assembly was obtained having a packing formed therein. The packing formed in this way adhered sufficiently well to the surface of the cover material.

Next, the obtained cover/packing assembly was filtered through a 0.5 μm filter to reduce the conductivity to 10 μm.
Wash with pure water at a cleanliness level of 100 (0.3
When a hard disk drive was assembled by integrating the above cover/packing assembly with a hard disk container while maintaining its cleanliness after air drying in a room with micrometers (μm), the resulting hard disk drive had excellent airtightness and cleanliness. Leak tests and cleanliness tests revealed that Therefore, it has been confirmed that the above-mentioned cover/packing assembly is extremely useful as a cover assembly for a hard disk drive.

Leak test method: After pressurizing the inside of the hard disk drive to 100 mH2O, the pressure was measured after 1 minute had elapsed. In the case of this example, it was 99 mH2O, which was sufficiently good. The general physical properties and moisture permeability coefficient of the acrylonitrile butadiene rubber of Composition Example 1 shown in Table 1 were as shown in Table 2 below.

[0029]

[Table 2] ────────────────
──────── Hardness (JI
S-A) 4
3 ──────────────
───────── Growth

430% ────────
────────────────
tensile strength
25Kg/cm2
────────────────────────
tear strength
10Kg/cm2
──────────────────
────── Moisture permeability coefficient
15.0g mm/m2 24 hours ────────────────
────────

Example 2. Using a coating robot (manufactured by Yaskawa Electric Co., Ltd.), apply the following Table 3 onto the aluminum top cover whose surface has been electrodeposited with epoxy resin according to a pre-memorized pattern.
A liquid acrylonitrile butadiene rubber of Composition Example 2 shown in is applied.

[0031]

[Table 3] Composition Example 2; ────────────────────────
─────────── Acrylonitrile butadiene polymer with carboxyl groups at both ends: 100 parts by weight
(Hycar CTB 1300×31 manufactured by Ube Industries, Ltd., product name), Epoxy polymer:
12.5 parts by weight (
Epicon #850 (manufactured by Dainippon Ink & Chemicals Co., Ltd., product name), curing catalyst:

0.74 parts by weight (tetraethylenepentamine), Ketjen EC600
JD:
4 parts by weight (Product name manufactured by Ketjen Black International Co., Ltd.)
, Erosil 200:

2 parts by weight (trade name manufactured by Nippon Aerosil Co., Ltd.) and antioxidant:

0.5 parts by weight
(2,6-di-t-butyl-4-methylphenol). ────────────────────────
────────────

Coating conditions are: nozzle inner diameter: 1.8 mmφ, supply pump pressure: 1.8 kgf
/m2, coating speed: 100mm/min, dispenser rotation speed: 20rpm, nozzle height (from cover surface):
2.0mm, and after coating, it was heated to 130℃.
When the mixture was placed in a hot air dryer and then cooled, a cover/packing assembly was obtained which formed a packing having a semicircular cross section with a height of 1.5 mm and a width of 2.1 mm. The packing formed in this way adhered sufficiently well to the surface of the cover material.

Next, the obtained cover/packing assembly was filtered through a 0.5 μm filter to reduce the conductivity to 10 μm.
Wash with pure water at a cleanliness level of 100 (0.3
After air-drying in a room with micrometers (μm), the cover/packing assembly was integrated with a hard disk container while maintaining cleanliness to assemble a hard disk drive.The resulting hard disk drive had excellent airtightness and cleanliness. Leak tests and cleanliness tests revealed that Therefore, it has been confirmed that the above-mentioned cover/packing assembly is extremely useful as a cover assembly for a hard disk drive. In addition, composition example 1 shown in Table 3
The general physical properties and moisture permeability coefficient of the acrylonitrile butadiene rubber were as shown in Table 4 below.

[0034]

[Table 4]

Claims (2)

[Claims] [Claim 1] A hard disk drive cover with packing applied to the joints of the hard disk drive cover.
1. A cover/packing assembly for a hard disk drive, wherein the packing is made of hardened liquid acrylonitrile butadiene rubber. 2. A method of manufacturing a cover/packing assembly for a hard disk drive, comprising applying liquid acrylonitrile butadiene rubber to a predetermined position of a cover for a hard disk drive by the FIPG method, and then curing the rubber to form a packing.