JP2000048552A - Hard disk component coated with poly-p-xylene - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent outgas constituents from being generated without losing performance and dimension accuracy that component originally have by coating the components for generating the outgas consisting of rubber and a magnet or scattering a magnetic powder with poly-p-xylylene or is derivative. SOLUTION: Poly-p-xylylene is obtained by the gaseous phase vapor deposition polymerization method and is made of each or the combination of a monomer-hexamer of 5,000 degree-of-polymerization of poly-p-xylylene, polymonochloro-p-xylylene, and polydichloro-p-xylylene. Vapor deposition processes consist of a first process where a solid 2 hexamer di-p-xylylene is sublimated at 100-200 deg.C with a degree-of-vacuum of 0.001-1 Torr, a second process where diradical-p-xylylene is polymerized due to thermal decomposition at 450-700 deg.C, a third process where a macromolecular amount of poly-p-xylylene is coated and formed at a room temperature. The obtained by poly-p-xylylene covering can be subjected to conformal coating to a cladding body. Also, since this process can be made at a room temperature, no thermal history can be given to the cladding body.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a component in which a component constituting a hard disk is coated with a polyparaxylylene film. More specifically, the present invention relates to a component which generates components harmful to the hard disk such as outgas and magnetic powder. The present invention relates to a hard disk component coated with a paraxylylene film.

[0002]

2. Description of the Related Art A storage device using magnetism or magneto-optics is used for a device requiring an external storage device such as a computer and a word processor. Among them,
Hard disk devices have a high recording / reproducing speed, are inexpensive for each recording capacity, and are used in most personal computers and workstations.

A hard disk drive records and reproduces information by a magnetic recording method. The general configuration is composed of a magnetic disk, a spindle motor, a magnetic head, an actuator (carriage, voice coil motor), and a case.

In a hard disk drive, a magnetic disk having a magnetic layer formed on the surface of a metal plate or a glass plate is rotated at a high speed, and a magnetic head approaches the magnetic disk to perform recording and reproduction. In order to increase the recording capacity of the hard disk, it is necessary to increase the track density and the bit recording density. In this case, the distance between the magnetic head and the magnetic disk must be reduced. This distance is very small and foreign matter is not allowed to adhere to the disk.

Therefore, it is necessary for the unit for storing the magnetic disk to block dust, dust, gas and the like from the outside. Therefore, various sealing materials including gaskets, packings, O-rings and the like have been used. An organic material having rubber elasticity is effective as a sealing material in order to effectively block the outside. However, what can be used as a sealing material is very limited. That is, the organic material itself generates a volatile substance called outgas.

[0006] Outgas is a gas in which a component contained in a substance escapes from the substance, and in many cases, impurities of the substance, organic solvents, and the like volatilize. When a component containing a substance that generates outgas is used for a hard disk, outgas is generated from the component in the hard disk after the hard disk is assembled and adheres to a magnetic disk or the like. If the outgas adheres to the magnetic disk, the reliability of recording / reproducing is significantly reduced, and the magnetic disk may be corroded or the magnetic head may be damaged.

[0007] Outgas components include moisture, organic solvents, unreacted raw materials, decomposed products of polymerization initiators, unreacted low molecular monomers such as acrylic monomers and siloxanes, oils such as grease and rust preventive oil, sulfur, bromine, and the like. Chemical reaction products such as chlorine; Outgases are generated from most organic materials. Although a very small amount of outgas is generated from metals and the like, it does not reach an amount that adversely affects the hard disk. Depending on the substance and the amount of outgassing, outgassing may be neglected or may need to be prevented. In particular, rubber should give priority to outgassing.

[0008] In the case of magnets such as ferrite magnets and plastic magnets, the generation of outgas is very small, but magnetic powder may be scattered. When the magnetic powder adheres to the magnetic disk, the data on the magnetic disk is destroyed. Further, the magnetic head collides with the magnetic head and is destroyed. For this reason, it is necessary to prevent the magnetic powder scattered from the magnet.

As a method of preventing the magnetic powder from scattering from the magnet, coating of the magnet surface with nickel plating or epoxy coating has been performed. However, these coatings are apt to cause pinholes, and it is very difficult to coat them completely without leakage of the magnetic powder. In order to perform coating so as not to cause pinholes, it is necessary to make the film thickness extremely large, and it is difficult to make such a coating uniform in film thickness. Further, there is also a problem that outgassing will occur in epoxy coating and the like.

A spindle motor for rotating a magnetic disk has a bearing in the motor, but this lubricant leaks. Therefore, a lubricant seal is disclosed in Japanese Patent Application Laid-Open No. 10-54420. In many cases, a bearing having a suitable seal ring is used. Further, a magnetic fluid seal or a seal having a labyrinth structure may be used. In recent years, these leakage prevention means have become essential conditions in order to prevent adhesion to a magnetic disk.

However, since an organic material or a magnet is used as the means for preventing the leakage of the lubricating oil, there is a problem that outgas and magnetic powder are generated from these members. The bearing uses a rubber packing for the bearing, and the magnetic fluid seal uses a member for generating a component harmful to the magnetic disk, such as a magnet for holding the magnetic fluid, which causes outgassing.

The components of the hard disk that generate outgas or magnetic powder are components of the spindle motor, such as a magnetic fluid holding material of a magnetic packing portion, a seal ring of a bearing portion, a self-fusion line of a stator coil portion, and a drive. For the components that make up the magnetic head, wire tubes for signal transmission lines, for the components that make up the actuator, ferrite magnets such as fan magnets and latch magnets, for the stopper rubber, and for the components that make up the case, Seal packing is exemplified.

As described above, the hard disk drive must be designed so as not to generate fine particles such as outgas and magnetic powder. As a countermeasure, use a modified material that does not easily generate fine particles such as outgas and magnetic powder, or put the hard disk part under high temperature vacuum to volatilize outgas components in advance and incorporate it into the hard disk device In this state, the outgas component is reduced as much as possible.

[0014]

As a method for reducing the outgassing described above, the method of improving the parts to a material which is less likely to generate outgassing has the disadvantage that the original function of the material is impaired and the manufacturing process becomes complicated. is there. For example, if an O-ring used as a sealing material is made of a composition that suppresses generation of outgas, flexibility and durability deteriorate, and the function as a sealing agent must be sacrificed. In addition, disadvantages increase such that the heating temperature must be higher in order to cure and the heating time must be longer. Further, the above-mentioned composition has a disadvantage that the cost of the raw material itself increases.

As a method of reducing outgas, a method of preliminarily volatilizing outgas components by placing an organic material under a high-temperature vacuum can reduce the amount of outgas generated after being incorporated into a hard disk to some extent, but the amount is insufficient. However, outgassing occurs in long-term use. Further, there is a disadvantage that the organic material is deteriorated or deformed by prolonged exposure under a high temperature vacuum. For this reason, it has sometimes been necessary to change to parts that do not generate outgas components.

[0016]

SUMMARY OF THE INVENTION The present invention solves the problems associated with parts for use in hard disks as described above. That is, the present invention provides a hard disk component characterized in that the hard disk component is coated with polyparaxylylene or a derivative thereof. The feature of the present invention is remarkable because the hard disk component generates outgas. Further, the hard disk component that generates the outgas is a component that further includes rubber. In addition, the hard disk component that generates outgas is a component that includes a magnet, which is a remarkable feature.

[Detailed Description of the Invention] The basic structure, production method, polymerization method and the like of polyparaxylylene used in the present invention are described in US Pat. No. 3,379,803, Japanese Patent Publication No. 44-21353, and Japanese Patent Publication No. 45-31
No. 787 and JP-B-52-37479, specifically, polyparaxylylene, polymonochloroparaxylylene, and polydichloroparaxylylene. In addition, the degree of polymerization is 5000 or more. These may be used alone or in combination.

Polyparaxylylene is formed by a vapor phase vapor deposition polymerization method, and the vapor deposition process consists of three processes. That is, the first step in which the solid dimer diparaxylylene as a raw material is vaporized (sublimated), the second step in which diradical paraxylylene is generated by thermal decomposition of the dimer,
This is the third step in which the adsorption and polymerization of diradical paraxylylene on the adherend are simultaneously performed, and the formation of a film of high molecular weight polyparaxylylene occurs.

During this process, the degree of vacuum is generally 0.1.
001 to 1 Torr and the first step is 100 to 200
C., the second step is performed at 450-700.degree. C., and the third step is performed at room temperature.

These polyparaxylylene films obtained by the vapor deposition polymerization method can be conformally coated on an adherend, and since the coating is performed at room temperature, the heat applied to the adherend can be reduced. It also has features on the processing surface such as not giving a history.

The components that constitute the hard disk and generate outgas and magnetic powder are the components that constitute the spindle motor, such as the magnetic fluid holding material of the magnetic packing portion, the seal ring of the bearing portion, the self-bonding wire of the stator coil portion, and the drive. Ferrite magnets for the magnetic head, the wire tube of the signal transmission line for the components that make up the magnetic head, the ferrite magnets such as the fan magnet and latch magnet for the components that make up the actuator, the stopper rubber, and the parts that make up the case Seal packing is exemplified.

By applying the present invention, there is no need for a special compound to reduce outgassing, for example, rubber such as NBR can be used, cost is not required, and elasticity of the rubber body is required. Can also be used in places.

Although it is different from the purpose of suppressing the generation of outgas, by coating the stator core with polyparaxylylene, the effect of rust prevention and corrosion prevention can be obtained.

[0024]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to embodiments. In Example 1, a seal ring made of NBR of a bearing portion, which is a component constituting a spindle motor of a hard disk, was used. The seal ring made of NBR seals the outer peripheral edges of the inner ring and the outer ring sandwiching the sphere of the bearing, and is a packing for sealing the lubricating oil of the bearing. After the seal ring is washed with isopropyl alcohol and dried, the degree of vacuum is 1.3 Pa (0.01 Torr).
r), a first stroke temperature of 120 ° C, a second stroke temperature of 690 ° C,
The third process temperature was room temperature, and polyparaxylylene was vapor-deposited under the condition that the raw material used was a monochloropolyparaxylylene dimer. As a result, a seal ring coated with the polyparaxylylene film was obtained.

As Comparative Example 1, the same seal ring as in Example 1 was subjected to only isopropyl alcohol cleaning to obtain a seal ring not coated with a polyparaxylylene film.

In Example 2, a rubber part made of EPDM, which is a stopper of a carriage in an actuator section of a hard disk, was used. A stopper rubber was coated with a polyparaxylylene film in the same procedure as in Example 1. As Comparative Example 2, a stopper rubber having no polyparaxylylene coating was obtained only by the same washing.

In the third embodiment, a magnet for holding a magnetic fluid in a magnetic packing portion, which is a component constituting a spindle motor of a hard disk, was used. After washing the magnet with isopropyl alcohol and drying, the degree of vacuum is 1.3P.
a (0.01 Torr), the first process temperature was 120 ° C., the second process temperature was 690 ° C., the third process temperature was room temperature, and polyparaxylylene was vapor-deposited under the condition that the raw material used was monochloropolyparaxylylene dimer. . Thus, a magnet coated with a polyparaxylylene film was obtained. Comparative Example 3
In the same manner, a magnet not coated with polyparaxylylene was obtained only by washing.

In Example 4, a latch magnet used for an actuator of a hard disk was used. The latch magnet was coated with a polyparaxylylene film in the same procedure as in Example 3. As Comparative Example 4, a part only for cleaning was obtained.

Example 1, Example 2, Comparative Example 1, Comparative Example 2
Each of the parts obtained in the above was placed in a sealed container one by one, and the gas generated when heated at 85 ° C. for 3 hours under extraction conditions was analyzed by GC-MS to measure the outgas amount. As a result, Example 1
52 ng, Comparative Example 1 4378 ng, Example 2 176
ng and Comparative Example 2 were 2478 ng.

Example 3, Example 4, Comparative Example 3, Comparative Example 4
The parts obtained in the above were rubbed with a cloth impregnated with isopropyl alcohol. This cloth was observed under a microscope. As a result, no magnetic powder was confirmed in Examples 3 and 4, but a large amount of magnetic powder was confirmed in Comparative Examples 3 and 4. When the epoxy-coated magnet was similarly tested, magnetic powder was confirmed.

[0031]

The polyparaxylylene film has a very small amount of outgas despite the thermoplastic resin, and does not generate any amount and type of outgas that adversely affects the magnetic disk of the hard disk. In addition, thin films can be conformally coated with substances that generate a large amount of outgas, such as rubber and plastic, and can firmly adhere to these substances. Since the polyparaxylylene coating film has extremely low gas permeability, these parts do not generate outgas.

Also, no pinholes are produced even when the thin film is coated. Therefore, the coating film can be made thinner, and the original performance of the sealing material and the elastic material is not impaired without hindering the followability and the elongation of the elastic material such as rubber. In addition, since pinholes do not occur even though the film is thin, parts made of materials that could not be used due to the possibility of outgassing may be used for hard disk parts in order to reliably prevent outgassing of uncoated substances. This is advantageous in terms of work process and cost.

Further, since the polyparaxylylene film can be conformally coated and has a constant film thickness, the dimensional stability of the component is high. From these facts, it is extremely useful to use the component of the present invention for a hard disk.

Claims (4)

[Claims] 1. A hard disk component comprising a hard disk component coated with polyparaxylylene or a derivative thereof. 2. The hard disk component according to claim 1, wherein the hard disk component generates outgas. 3. The hard disk component according to claim 2, wherein the hard disk component generating the outgas is a component containing rubber. 4. The hard disk component according to claim 1, wherein the hard disk component generating outgas is a component including a magnet.