JP2001048283A - Disc carrier and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable crystallization of thermoplastic polyamide resin having a specified structure in a metal mold by molding it in the metal mold and obtain a disc carrier excellent in dimensional stability and heat resistance. SOLUTION: A disc 1 is produced by crystallization of polyamide resin as a raw material shown in an expression in a metal mold under a specified condition while using an injection molding machine equipped with the metal mold. In this case, inwardly confronted rugged guides 2, side plates 3, ribs 4, etc., are integrally or separately formed and assembled by fitting, adhesion, etc. Further, in this time, respective shapes of the guides 2 may be any one of linear type, rugged type, corrugated type, etc. Moreover, these may be integrally formed and a comblike guide part may be formed in one of a pair of moldings or after one or more sheets are formed, a shaft or the like may be used to fit or adhered it to the side plates 3 and assembled to constitute the disc carrier.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used for processing, storing, and transporting a hard disk made of aluminum or the like as a magnetic information recording medium of a hard disk device used as an external storage means of an information processing device such as a computer. Disc carrier.

[0002]

2. Description of the Related Art In the process of manufacturing a magnetic information recording medium, a disk carrier is generally used when processing, storing and transporting a hard disk made of aluminum or the like. The use of a disc carrier in the manufacturing process means that the processing in each process, transportation between processes, and storage before and after each process can be performed by an automatic machine, which simplifies the manufacturing process and improves the yield of hard disks. To contribute.

A hard disk is easily scratched because it is formed from relatively soft aluminum or the like. Therefore, a metal carrier cannot be used. For this reason, several types of resin carriers have been commercially available. However, since a high temperature is required depending on the process, a disc carrier using polyetheretherketone as a heat-resistant resin has been proposed (Japanese Patent Publication No. 6-3 / 1994).
No. 8413).

However, even with such a polyetheretherketone resin, its properties cause a decrease in the elastic modulus when the resin exceeds a glass transition temperature of 150.degree. Since the whole and the top of the opening for inserting and removing the disk are distorted and warped, they can be used only in a limited temperature range. In particular, when the temperature exceeds 270 ° C., a problem such as rapid thinning occurs at the inwardly facing concave-convex guide portion for aligning and spacing the disk in the axial direction of the disk carrier. In particular, the thinning phenomenon causes a change in dimensions and changes the interval at which the guides are to be separated, so that when the disc is inserted or removed, an erroneous operation of the automatic machine is caused, and there is a risk of damaging the disc.

[0005] In order to prevent distortion and warping in such a high temperature region, a filler such as glass fiber is combined with the resin,
There have been proposals to improve the strength of the entire disc carrier. However, there is a possibility that glass powder may be generated by rubbing between the glass fiber and the hard disk, and there is a fear that such glass powder may adversely affect a subsequent process.
It was not an appropriate solution.

[0006] As a method for solving these problems, a resin composition having excellent heat resistance is disclosed in JP-A-62-2368.
There is an example in which a disk carrier described in Japanese Patent Application No. 9-66485 has been developed using a polyimide resin as described in Japanese Patent Publication No. 58-58 and the like. The polyimide resin has excellent performance in thermal properties, mechanical properties, and the like, and is therefore used in a wide range of fields. However, the crystallization rate of the polyimide resin alone is low, and crystallization is not achieved in the injection mold, and the molded product is obtained as an amorphous product. In order to further exhibit the heat resistance and chemical resistance peculiar to the polyimide resin, it is effective to use a crystallized resin. However, in order to crystallize the polyimide resin, it is necessary to heat-treat a molded article once in an amorphous state using an oven or the like and then to crystallize the molded article. However, in this method, the deformation and dimensional change accompanying crystallization increase, and it is difficult to obtain a satisfactory one.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to provide a polyimide disk carrier having excellent heat resistance and excellent dimensional stability even at high temperatures in view of the above problems, and a method for producing the same. .

[0008]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to solve the above-mentioned problems. As a result, the present inventors have found that a thermoplastic polyimide resin having a specific structure is used to form a crystal in a mold. And found that a disk carrier having excellent dimensional stability and heat resistance can be obtained, and completed the present invention. That is, the present invention relates to a compound represented by the general formula (1):

[0009]

Embedded image

This is a polyimide resin disk carrier molded from a polyimide resin having a repeating structural unit represented by the formula:

In a preferred embodiment of the polyimide resin disk carrier of the present invention, the disk carrier has an open top for insertion and removal of the disk, and inwardly aligns the disk with the disk carrier in the axial direction. A disk carrier provided with opposing concave-convex guides, wherein the guide, which is at least a contact portion of the disk carrier with a disk, is formed of a polyimide resin having a repeating structural unit represented by the general formula (1). One. Polyethylene ether ketone or the like may be substituted for 45% by weight or less of the polyimide resin.

Another aspect of the present invention is the above-mentioned method for manufacturing a polyimide resin disk carrier, wherein the cylinder temperature is 400 to 450 using an injection molding machine equipped with a mold.
A method for producing a disk carrier made of polyimide resin, wherein a disk carrier is injection-molded from the above polyimide resin at a temperature of 200 ° C. and a mold temperature of 200 to 250 ° C., and crystallized in the metal mold.

The polyimide resin disk carrier according to the present invention uses a polyimide having a repeating structural unit represented by the above general formula (1) as a raw material, so that an injection-molded product can be formed in a mold of an injection molding machine. Since it is crystallized, it is not necessary to crystallize it by heat treatment or the like in the next step after taking it out of the mold. Accordingly, not only the process is simplified, but also the polyimide resin disk carrier has extremely high dimensional accuracy and a small dimensional change rate at high temperatures.

The disk carrier of the present invention is loaded into a continuous or batch-type oven at a temperature of more than 270 ° C. while holding a plurality of hard disks made of aluminum or the like, and is used for baking or magnetizing the hard disks. . Even when used under such a condition exceeding 270 ° C., the dimensional change rate of the disk carrier of the present invention is extremely small, so that it can be used repeatedly.
Incidentally, the dimensional change rate in the present invention is a value measured by a method described in Examples described later.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail. As shown in FIG. 1, the disk carrier of the present invention has an inwardly facing concave-convex guide 2 for spacing the disk in alignment with the axial direction of the disk carrier 1. This is a configuration having a rib 4 or the like arbitrarily. The hard disk 5 is held by the opposing guides 2 as shown in FIG. Therefore, the only member that contacts the hard disk 5 is the guide 2. Other members, such as a shaft, a side plate, and a mounting bolt, may be made of metal, but are not particularly limited as long as they have sufficient heat resistance so as not to deform even under a condition exceeding 370 ° C.

In the configuration shown in FIG. 1, the guide 2, the side plate 3,
The ribs 4 and the like are formed by integral molding, but these components are used as separate members to fit, adhere, fuse, pin, screw, insert, outsert, integrate, multicolor, etc. May be assembled. The individual shapes of the guide 2 are linear, concave and convex, corrugated, trapezoidal,
Any of a triangle, an ellipse, a circle, a polygon and the like may be used, and these may be integrally formed to form one comb-shaped guide portion of each pair. Using a shaft made of a material that does not deform even under conditions exceeding ℃, it is fitted to the side plate, adhered, fused,
The disk carrier may be configured by assembling by pinning, screwing, or the like. At the time of integral molding and assembly thereof, it is necessary to appropriately change the shape of the carrier, and it is apparent that the configuration is not limited to the configuration shown in the drawings.

The polyimide resin disk carrier according to the present invention is a polyimide resin having a repeating structural unit represented by the above general formula (1) under specific conditions using an injection molding machine equipped with a mold. It is manufactured by molding a disk carrier using as a raw material and crystallizing it in a mold. The polyimide resin used as a raw material of the disk carrier according to the present invention is a crystalline resin and a resin having a repeating structural unit represented by the general formula (1).

The polyimide resin has 1,3-bis (4-aminophenoxy) benzene as a diamine component, and 3,3 ′, 4 as a tetracarboxylic dianhydride component.
It is produced by using 4,4′-bisphenyltetracarboxylic dianhydride and dehydrating and co-condensing the two. The molar ratio of the tetracarboxylic dianhydride component to the diamine component may be about 0.90 to 0.99. The reaction temperature is from room temperature to 250 ° C, preferably 140 to 200 ° C. The molecular weight of the polyimide resin is 0.1 in logarithmic viscosity (η _inh ).
It is in the range of 1 to 3.0 dl / g. Preferably 0.2 to
2.0 dl / g, more preferably 0.3 to 1.5
dl / g, most preferably 0.4-1.0 dl / g.
g. If it is less than 0.1 dl / g, the molecular weight is low and the strength as a molded product cannot be sufficiently exhibited. 3.0
If it exceeds dl / g, the molecular weight is too high, and melt molding such as injection molding becomes difficult. The logarithmic viscosity (η) in the present invention
_inh ) is a mixture of p-chlorophenol / phenol (weight ratio: 9/1) in a mixed solvent of 100 ml with 0.5% polyimide powder.
g is measured at 35 ° C. after heating and dissolving g.

A part of the polyimide resin can be replaced by another thermoplastic resin. Examples of the thermoplastic resin that can be substituted include polyether ether ketone, polyether ketone, polyether sulfone, polyetherimide, polyether ketone ether ketone, polyethylene, polypropylene, polystyrene, polycarbonate, polyester, and polyamide. , Polyamide imide, polyphenylene ether, polyacetal, polyether sulfone, polysulfone, and other thermoplastic polyimides. Of these, preferred are polyetheretherketone, polyetherketone, polyethersulfone, polyetherimide and the like.

These resins may be used alone,
You may substitute using two or more types. The most preferred alternative resin is polyetheretherketone. If the substitution amount is too large, crystallization in the mold during injection molding tends to be difficult. In consideration of such a point, the substitution amount is preferably within 45% by weight of the polyimide resin.

The resin composition used in the present invention can be produced by a known method, but the following method is particularly preferable.
(1) The polyimide resin powder and, if necessary, other resin are pre-mixed using a mortar, a Henshal mixer, a drum blender, a tumbler blender, a ball mill, a ribbon blender, and the like. After kneading with a mixer, a hot roll or the like, the mixture is formed into pellets or powder. (2) Polyimide resin powder and, if necessary, other resin are dissolved or suspended in an organic solvent in advance, and the solvent is removed in a hot air oven, and then pelletized or powdered.

As the solvent used in the latter method, for example, N, N-dimethylformamide, N, N-dimethylacetamide, N, N-diethylacetamide, N, N-diethylacetamide
N-diethylacetamide, N, N-dimethylmethoxyacetamide, N-methyl-2-pyrrolidone, 1,3-
Dimethyl-2-imidazolidinone, N-methylcaprolactam, 1,2-dimethoxyethane, bis (2-methoxyethyl) ether, 1,2-bis (2-methoxyethoxy) ethane, bis [2- (2-methoxy Ethoxy) ethyl] ether, tetrahydrofuran, 1,3-dioxane, 1,4-dioxane, pyridine, dimethylsulfoxide, dimethylsulfone, tetramethylurea, hexamethylphosphoramide and the like. These organic solvents may be used alone or in combination of two or more.

The polyimide resin disk carrier according to the present invention is manufactured by injection molding using the resin composition manufactured as described above as a raw material and using an injection molding machine equipped with a mold. . In the injection molding, the cylinder temperature is set to 400 to 450 ° C., and the injection pressure is set to 500 to 3500.
Under a condition of kg / cm ² , the material is injected into a mold controlled at 200 to 250 ° C. and crystallized in the mold. By molding under such conditions, it is possible to crystallize in a mold of an injection molding machine without providing a dedicated crystallization step in the next step. The general formula (1) used in the present invention.
Polyimide resin having a repeating structural unit represented by
The crystallization rate of the resin composition containing the resin as a main component is high. Crystallization is easily achieved in the mold under the above conditions. Therefore, after molding, it is not necessary to carry out the crystallization treatment of the molded article in a separate step. Since the inherent heat resistance and chemical resistance of the polyimide resin are exhibited, and there is no need to perform a method such as post-crystallization, the process can be simplified and a molded product with less dimensional change can be obtained. Specifically, 290
At 200 ° C. for 200 hours.
0% or less. Preferably it is 5% or less.

On the other hand, a polyimide resin as described in the conventional Japanese Patent Application Laid-Open No. 62-236858 has a low crystallization rate, and does not crystallize by injection cooling after injection. Therefore, the molded product is taken out of the mold as an amorphous product. Therefore, in order to obtain higher heat resistance and chemical resistance, it is necessary to perform a crystallization treatment of the molded product by another process after molding. When it is removed from the mold and subjected to crystallization treatment in the subsequent process, the dimensional change becomes large and the dimensional accuracy decreases.

[0025]

EXAMPLES Hereinafter, the present invention will be described in detail with reference to examples, but it is apparent that the present invention is not limited to these examples. The dimensional stability shown in the examples was measured by the following method. (1) Dimensional change rate (%) The disk carriers manufactured in Examples and Comparative Examples
After holding in an oven at 0 ° C. for a predetermined time and cooling to room temperature, the “evaluation length” shown in FIG. 3 is measured, and the rate of change (percentage of the contraction length relative to the original length) is calculated. I do.

Preparation Example 1 <Synthesis of Polyimide Resin> 204.4 g (0.7 mole) of 1,3-bis (4-aminophenoxy) benzene and 34.4 g of 3,3-bis (4-aminophenoxy) benzene were placed in a vessel equipped with a stirrer, a reflux condenser, and a nitrogen inlet tube. ,
199.6 g (0.679 mol) of 3 ', 4,4'-bisphenyltetracarboxylic dianhydride, phthalic anhydride 6.
22 g (0.06 mol) and 1480 g of m-cresol were charged and heated to 200 ° C. while stirring under a nitrogen atmosphere. Thereafter, when the reaction was carried out at 200 ° C. for 4 hours, about 9 ml of water was distilled off during the reaction. After the completion of the reaction, the mixture was cooled to room temperature, charged with about 2000 ml of toluene, and then the polyimide powder was separated by filtration. After washing this polyimide powder with toluene, it was dried at 250 ° C./5 hours in nitrogen to obtain a polyimide powder. (Η) of the obtained polyimide resin
_inh ) was 0.9 dl / g and the heat distortion temperature was 400 ° C. The obtained polyimide resin was melt-kneaded at 410 ° C. with an extruder having a diameter of 40 mm to produce pellets.

Example 1 Using a pellet obtained in Preparation Example 1 as a molding material, a guide made of a polyimide resin (evaluation length: 50 mm) whose guide had a sectional shape shown in FIG. 3 was formed by injection molding. The main molding conditions are as follows. Injection molding machine:
The mold clamping force is 100 tons, the cylinder temperature is 420 ° C., the mold temperature is 210 ° C., and the injection pressure is 2200 kg / cm ² . The obtained guide was held in an oven for 50, 100, 150 and 200 hours by the above method, and the dimensional change rate was measured. The results are shown in [Table 1].

Comparative Example 1 Polyetheretherketone (trade name: PEEK, manufactured by Victrex MC) was used as a molding material. The molding conditions were as follows: cylinder temperature 400 ° C., mold temperature 200 ° C., injection pressure 2000 kg / cm ² . A guide made of polyetheretherketone (evaluation length: 50 mm) was prepared in the same manner as in Example 1 except that the above procedure was performed. The dimensional change was measured in the same manner as in Example 1. The results are shown in [Table 1].

[0029]

[Table 1]

As is apparent from Table 1, the dimensional change of the polyimide resin guide of the present invention is extremely small as compared with the known polyether ether ketone guide.

[0031]

The disk carrier made of a polyimide resin according to the present invention has excellent dimensional accuracy and heat resistance. According to the manufacturing method of the present invention, it is possible to crystallize in a mold of an injection molding machine, and it is not necessary to crystallize by taking out a heat treatment or the like in the next step after taking out from the mold. Therefore,
Not only the steps are simplified, but also a disk carrier made of a polyimide resin having a very high degree of dimension can be obtained.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an example of a disk carrier of the present invention.

FIG. 2 is a side view showing a state where a hard disk is inserted into a disk carrier.

FIG. 3 is a diagram illustrating an example of a cross-sectional shape of a guide unit.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Disc carrier 2 Guide 3 Side plate 4 Rib 5 Hard disk

 ──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Hirofumi Zenko 2-1-1 Tango-dori, Minami-ku, Nagoya-shi, Aichi Inside Mitsui Chemicals, Inc. (72) Inventor Hideto Ogasawara 2-1-1, Tango-dori, Minami-ku, Nagoya-shi, Aichi Address F-term in Mitsui Chemicals, Inc. (reference) 3E068 AA08 AB01 AC06 BB11 BB17 CC02 CD10 CE03 DD40 EE09 3E096 AA06 BA30 BB04 CC02 DA05 DA23 DA30 DC01 EA02X FA14 FA16 4J002 CH092 CM041 GS00

Claims (6)

[Claims] [Claim 1] General formula (1) A polyimide disc carrier molded from a polyimide resin having a repeating structural unit represented by: 2. The polyimide resin disc carrier according to claim 1, wherein 45% by weight or less of the polyimide resin is replaced by polyetheretherketone. 3. The polyimide resin disk carrier according to claim 1, wherein the dimensional change rate when held at 290 ° C. for 200 hours is 10% or less. 4. A disk carrier having an open top for insertion and removal of a disk, and having inwardly facing concave and convex guides for spacing the disk in axial alignment with the disk carrier. 2. The disk carrier according to claim 1, wherein the guide, which is at least a contact portion of the disk carrier with the disk, is formed of a polyimide resin having a repeating structural unit represented by the general formula (1). Disc carrier made of polyimide resin. 5. The disk carrier according to claim 1, wherein the disk carrier is for storing a hard disk.
5. The polyimide disc carrier according to any one of the above items 4. 6. The method for producing a polyimide resin disk carrier according to claim 1, wherein:
Using an injection molding machine equipped with a mold, a disk carrier is injection-molded from a polyimide resin at a cylinder temperature of 400 to 450 ° C. and a mold temperature of 200 to 250 ° C., and crystallized in the mold. Of producing a polyimide resin disk carrier.