JPH101177A - Disk case - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress generation of fine particles due to contact with a disk to improve sizing stability and impact resistance by molding a disk case of polymer blend comprising a main material of polycarbonate and a predetermined quantity of fluorine resin blended. SOLUTION: A disk case having at least one opening face 1 and equipped with a support groove 6 for supporting a disk 4 on an inner face of opposite side walls 2 is molded of polymer blend comprising 97 to 65wt.% of polycarbonate and 3 to 35wt.% of fluororesin. Thus the disk case is excellent in sizing stability and impact resistance by a simple means of selecting, as its molding material, polymer blend with a specific quantity of fluororesin blended to polycarbonate without a troublesome method, wherein its hardness can be adjusted so that it may not damage a disk, and especially generation of fine particles which attach to the disk and adversely affect a performance of a precision electronic part can be remarkably suppressed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to polishing, chemical treatment, and the like of a disk such as a hard disk substrate and a semiconductor wafer.
Annealing treatment, used in carrying out various treatments such as plating and transporting the disk, particularly suitable for storage,
The present invention relates to a disk case for holding a large number of disks through an interval.

[0002]

2. Description of the Related Art It is important to ensure surface smoothness of disks such as silicon wafers and hard disk substrates in order to obtain reliable operation of integrated circuits and hard disks. However, the discs are easily damaged and the thickness is as thin as 0.6 to 1.5 mm, so dozens of discs are spaced so that they will not be damaged by mutual contact or contact with others during handling. It is housed in a disk case that holds it open, moved, stored, and processed. Various such cases have already been proposed. For example, Japanese Utility Model Laid-Open No. 4-13938, Tokuhei 3-50
No. 0713 and Japanese Utility Model Application Laid-Open No. 61-49450.

[0003] The manufacturing process of a semiconductor wafer, a hard disk or the like includes many processes such as a polishing process, a chemical treatment process, an annealing process, a plating process, and a cleaning process. Therefore, the disk case which accommodates these disks and undergoes each processing step is naturally required to have chemical resistance, heat resistance and impact resistance. In addition, discs require precision, so even if they are fine,
The adhesion of dust has a great effect on its performance. However, the disk case is worn and generates fine particles due to contact with the disk during storage or movement of the disk. These fine particles scratch or adhere to the disk. Therefore, in addition to the above-mentioned required performance, it is also important that the disk case be made of a material that does not generate fine particles upon contact with such a disk.

Hitherto, polypropylene, fluororesin, polycarbonate, and the like have been used as constituent materials of the disk case. Polypropylene is inexpensive but has low heat resistance and impact resistance, and has a large shrinkage and high dimensional stability. Inferior. Further, fine particles may be generated from a contact portion with the disk. Polycarbonate is excellent in dimensional stability and impact resistance, but fine particles are generated by contact with a disk or the like, and the disk may be damaged due to its hardness. Fluororesins are also excellent in heat resistance and chemical resistance and are less likely to generate fine particles, but have a large shrinkage during molding, are difficult to obtain dimensional accuracy, have insufficient strength, and are expensive.

[0005] For this reason, inexpensive polypropylene or polycarbonate disk cases are used in the transfer between processes and in the polishing step where high heat resistance and chemical resistance are not required, and high heat resistance and high chemical resistance are required. In this process, a disk case made of fluororesin or liquid crystal polymer is used.

Further, there has been proposed a case in which the problem of poor strength of the fluororesin is improved by coating the liquid crystal polymer with a fluororesin (Japanese Unexamined Patent Publication No. 3-9595).
No. 4). This disc case has heat resistance, chemical resistance,
It is considered that the strength is excellent and the generation of fine particles is suppressed.

[0007]

However, since the above-mentioned disk case goes through a manufacturing process of coating a fluororesin after injection molding of a liquid crystal polymer, the material is expensive and the manufacturing cost is high. . Under these circumstances, the present invention provides a disk case that can suppress the generation of fine particles due to contact with the disk, does not damage the disk, has excellent dimensional stability and impact resistance, and can be manufactured at low cost. It is intended to provide.

[0008]

As a result of intensive studies, the present inventor has found that it is effective to select a polymer blend composed mainly of polycarbonate as a molding material of a disc case and a fluororesin mixed therewith. And found the present invention.

That is, according to the present invention, there is provided a disk case having at least one opening surface and provided with a support groove for supporting a disk on inner surfaces of opposing side walls, wherein the disk case has a polycarbonate content of 97 to 65% by weight, and The present invention relates to a disk case formed from a polymer blend containing 3 to 35% by weight of a fluororesin.

The molding material of the disk case used in the present invention comprises 97 to 65% by weight of polycarbonate and 3 to 35% by weight of fluororesin as described above. If the fluororesin is less than 3% by weight, the effect of preventing the generation of fine particles due to contact with the disk will not be exhibited, and if it exceeds 35% by weight, the strength such as impact resistance will decrease, the weight will increase, and the cost will increase. I do. Particularly preferred from the balance between cost and performance is a case where the fluororesin is blended at about 10% by weight.

The polycarbonate used in the present invention is not particularly limited, and those usable as a molding material can be used. The same applies to the fluororesin, but PTFE (polytetrafluoroethylene), PFA
Is preferred. Various additives can be added to the resin molding material used in the present invention, if necessary.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS It is important for the disk case of the present invention to use a specific molding material as described above.
Its structure is not particularly limited,
Any case may be used as long as it has a structure capable of holding the disk at an interval on the inner surface of the side wall facing at least one opening surface. However, an example is shown in FIG. 1 for explanation.
FIG. 1 is an explanatory view of a disk case, wherein a is a perspective view of a disk housed therein, and b is a perspective view of the disk case. FIG. 2 is a perspective view of the disk case shown in FIG. 1b in an inverted position. In FIG. 1, 1 is an opening surface, 2 is a pair of side walls, and 6 is a groove in which the end 5 of the disk 4 is engaged with the inner surface 3 and held.

Reference Example A test piece was molded from a polymer blend material consisting of 90% by weight of a polycarbonate resin (Lexan manufactured by Nippon GE Plastics) and 10% by weight of polytetrafluoroethylene. Using this test piece, the possibility of generating fine particles during use of the disk case was evaluated. In addition, the test piece which does not contain polytetrafluoroethylene and consists only of polycarbonate was used as a comparative test. A traverse abrasion test was performed under the following conditions. Aluminum thickness 0.8
mm, cut a 95mm diameter hard disk and weigh 2
Using a 50 g arc portion (disc cut) as a load element, this arc end is brought into vertical contact with the test piece and reciprocated 30,000 times in a direction parallel to the arc portion and in a direction perpendicular to the arc portion (perpendicular to the plane). I let it. At that time, the reciprocation distance was 60 mm, the speed was 30 reciprocations / minute, and the test temperature was room temperature.

The results are shown in Tables 1 and 2 below.

Table 1 Horizontal direction test results Test piece material Change in weight of test piece Surface roughness Evaluation Before test g After test g Reduction g RaμRmax μ Polycarbonate 13.40136 13.39572 0.00564 0.3 26.0 × Polycarbonate / Polytetrafluoro 13.88939 13.88798 0.00141 0.2 3.4 ○ Ethylene = 90/10 (weight) Table 2 Vertical test results Test piece material Test piece weight change Surface roughness Evaluation Before test g After test g Decrease g RaμRmax μ Polycarbonate 13.57100 13.51572 0.05528 0.1 128.8 × Polycarbonate / Polytetrafluoro 13.76911 13.76515 0.00396 0.2 8.8 ○ Ethylene = 90/10 (weight) Note: In Tables 1 and 2, ○ indicates that very few particles are generated during use of the disk case, and × indicates that many particles are expected to be generated. Show. Further, Ra indicates the average roughness, and Rmax indicates the maximum depth.

Example 1 A disk case having the structure shown in FIG. 1 was prepared by injection molding a polymer blend of polycarbonate and polytetrafluoroethylene having the same composition as the above-mentioned test piece. Each processing step was performed with the aluminum hard disk stored in this disk case.
The generation of fine particles during use was extremely small, and even if they adhered to the disk, they could be easily removed by washing.

[0017]

As described above, the disk case of the present invention can be used as a molding material simply by using a specific amount of fluorine with respect to polycarbonate, without using a complicated method such as coating a molded article with a fluororesin. By simple means of selecting a polymer blend containing resin, it has excellent dimensional stability and impact resistance, its hardness is adjusted and it does not damage the disk, especially it adheres to the disk and impairs the performance as a precision electronic component Generation of fine particles can be significantly suppressed.

[Brief description of the drawings]

FIG. 1 is an explanatory view of a disk case, wherein a is a perspective view of a disk stored therein, b is a perspective view of a disk case,

FIG. 2 is a perspective view of the disk case shown in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Opening surface 2 Side wall 4 Disk 6 Disk holding groove

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code Agency reference number FI Technical display location H01L 21/68 0333-3E B65D 85/38 R

Claims (1)

[Claims] 1. A disk case having at least one opening surface and having a support groove for supporting a disk on inner surfaces of opposing side walls, wherein the disk case is made of 97 to 65% by weight of polycarbonate, and 3 to 4% of fluorocarbon resin. A disk case formed from a polymer blend comprising 35% by weight.