JPS6216283A - Jacket for floppy disk - Google Patents

Abstract

PURPOSE:To stabilize a disk to the change of environmental conditions and to minimize a soft error by sticking the unwoven fabric of polyacrylonitrile fiber at the inside of the sheet of post-chlorinated vinyl chloride resin and constituting a jacket. CONSTITUTION:At the inside of the sheet 1 consisting essentially of postchlorinated vinyl chloride, the unwoven fabric 3 consisting essentially of the polyacrylonitrile fiber is stuck to constitute the jacket 1 and an aperture 8 for driving a magnetic disk 2, an aperture 9 for reproduction and a starting point detecting hole 10 are provided. At the time of the 1% elongation of the machine direction of the unwoven fabric 3, the modulous is 400-50g/cm and the maximum endothermic peak of the differential thermal analysis of the sheet 1 is 90 deg.C or above. Consequently, the disk stored by the jacket which is excellent in the thermal stability and does not have the elongation and the camber at the time of the high temperature is stabilized and the soft error can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION a. Field of Industrial Application The present invention relates to a technology for improving floppy disks that serve as external storage media for small computers and word processors, and more particularly to a jacket for a floppy disk that accommodates a magnetic disk. .

b. Prior Art With the spread of Ali devices, floppy disks, which serve as the storage part of computers, microcomputers, word processors, etc., have come into wide use.

In the past, floppy disks were used in favorable environments such as computer rooms that were controlled under certain conditions, but recently they have been used in general offices, 9 workplaces, and shops.

They are increasingly being used in environments where temperature and humidity are not balanced, such as in homes, and where the level of cleanliness is poor. In addition, the drives used have become thinner, and floppy disks are often used at high temperatures. Furthermore, as the density of the magnetic disks used continues to increase, the area per bit becomes smaller, which tends to increase the frequency of error occurrence.

However, even under such conditions, floppy disks are required to operate with high reliability, and quality improvement to increase the reliability of floppy disks has become an important issue.

A floppy disk consists of a flexible disk (hereinafter referred to as a disk), which is a magnetic recording medium punched into a disk shape, and a jacket (sometimes called a case or shell) that houses the flexible disk. A liner is lined inside the jacket for the purpose of removing dust on the magnetic recording medium.

When the disk rotates, the liner and the disk come into proper contact, and foreign matter on the disk is effectively removed.

By the way, foreign substances that adhere to the disk include those that enter from the outside of the jacket through the opening, and those that are generated inside the jacket.

The former includes sand, dust, and fibrous garbage.

Further, there are many other types of lint, such as dust and fiber fragments generated from the liner itself, which greatly affect the reliability of floppy disks.

The liner is usually made of a non-woven material mainly made of rayon, and has mainly been used as a binder-based non-woven fabric in which the fibers are fixed with an adhesive or a binder-free non-woven fabric in which the fibers are heat-fused.

Such rayon-based nonwoven fabrics have relatively good cleaning properties, but have the drawbacks that they often generate resin powder fluff that is detached from the nonwoven fabrics, and that their physical properties change significantly due to humidity.

In addition, the jacket has a shape with good cleaning properties immediately after being manufactured, but when subjected to changes in temperature and humidity, the shape may change and the jacket may become deformed to a state where cleaning properties are poor. .

C1 Purpose of the Invention The present invention has been made in view of the above points, and as a result of conducting studies to improve the reliability of floppy disks, it is an object of the present invention to provide a jacket structure that is less prone to errors when environmental conditions change. be.

d1 Structure of the Invention The present invention relates to a jacket for housing a floppy disk, and is particularly adaptable to environmental changes. This jacket is a composite material consisting of a plastic sheet whose main component is post-chlorinated vinyl chloride resin, and a fibrous liner whose main component is polyacrylonitrile attached to the inside of this sheet (on the disk side). This jacket is folded in half, its periphery is joined, and openings and cutouts are provided at predetermined positions.

The present invention is an improvement of the jacket, and the improvement is that post-chlorinated vinyl chloride resin is used as the main component of the sheet to increase the heat resistance of the jacket and make it less susceptible to deformation due to changes in usage environmental conditions. Furthermore, by using a fibrous liner mainly composed of polyacrylonitrile as the liner attached to the sheet, dimensional changes are stabilized compared to the liner mainly composed of rayon, which has been widely used. In addition to suppressing the deterioration of the sheet made mainly of vinyl chloride resin, the jacket structure is based on the excellent dust retention ability of the nonwoven fabric made mainly of polyacrylonitrile fibers, and has a jacket structure that is extremely unlikely to cause errors under the usage environment. That is.

The plastic sheet for the jacket uses post-chlorinated polychlorinated vinyl resin, but this material contains polyvinyl chloride control, (meth)acrylic acid ester resin, polyoleon resin, etc. in a proportion of 50% by weight or less. It is also possible to mix them. A small amount of synthetic rubber may also be added as a modifier. Furthermore, carbon black, gA is used as a coloring agent.
It is common to add fees, etc. Similarly, additives such as stabilizers and lubricants may be added.

Conventionally, sheets made mainly of vinyl chloride resin have been used as jackets for floppy disks, but this may cause the jacket to deform under high temperatures, e.g., 50 to 60°C, and the liner and disk may deteriorate. Moderate contact becomes defective and leads to a soft error.

These thermal deformations can be greatly improved by using a sheet made of post-chlorinated vinyl chloride resin as the jacket material. When the state of this thermal deformation is investigated, it is related to the endothermic peak seen around 50°C to 120°C in the suggested thermal analysis. When these endothermic peaks are below 85°C, the temperature is 50°C.
It is difficult to suppress thermal deformation at ~60°C. Preferably, a sheet showing an endothermic peak of 90° C. or higher is used. In order to produce a clear endothermic peak, for example, polychlorinated vinyl chloride resin can also be produced by heat treatment.

The liner material used in the present invention is made of a nonwoven fabric made of fibers containing polyacrylonitrile as a main component. These nonwoven fabrics may contain a small amount of thermoplastic fibers such as polyester fibers and polyolefin fibers in addition to fibers mainly composed of polyacrylonitrile. Furthermore, as a fiber modifier, for example, an oil agent and an antistatic agent may be included. It is desirable to set the modulus of the acrylic liner to a low value in order to suppress jacket deformation due to fluctuations in jacket temperature and humidity. This is to make it difficult for the deformation stress of the liner due to changes in temperature and humidity to be transmitted to the sheet. The modulus of the liner itself at 1% elongation in the machine direction is 400 (J
It is desirable that there is one piece less than 1cm wide. In addition, in order to maintain appropriate cleaning properties, it is desirable to have a modulus at 1% elongation of 50g/1cm width or more.

Generally, a sheet and a liner are attached together through a process called tacking. To ensure sufficient adhesion between the sheet and liner, set the tacking dot spacing to 3 in the necessary areas.
It is preferable to make it less than mm. Further, it is preferable that the size of each dot is 0.5 mm or more. Since the adhesive strength between the acrylic liner and the post-chlorinated vinyl chloride resin is relatively weak, it is desirable to apply the above-mentioned tacking to areas where adhesion is essential, such as the four corners.

This well-tucked jacket material is folded to form a jacket in a conventional manner.

The magnetic disk cartridge of the present invention is characterized in that it is made from a liner made of acrylic fibers mainly made of the above-mentioned metachlorinated vinyl chloride resin, and its structure can be of any known structure. 1 to 3 are shown as examples of this structure.

The magnetic disk cartridge 1 is usually lined with a cleaning sheet 3 and has a structure that forms a space for rotatably housing a magnetic disk 2 punched into a donut shape, and has three bonding edges 5 on one side. ．． 5', 5
It is made by folding a rectangular sheet material 4 having a diameter of This cleaning sheet 3 comes to be interposed between the magnetic disk 2 and the cartridge 1.

The magnetic disk 2 is made of a flexible and elastic synthetic resin base film such as a polyester film, with a magnetic recording layer formed on one or both sides of the base film.
It is usually manufactured by punching it into a donut shape. A through hole 7 in the center of the magnetic disk 2 is a hole that engages with a rotary drive shaft of a recording/reproducing device, and a recording track of a predetermined value is formed on the outer periphery of the magnetic disk 2.

In the rectangular sheet material 4, there are magnetic disks 2 in two square parts separated by the center bending line (broken line 6).
A drive opening 8 corresponding to the through-hole 7 and having a larger diameter than the through-hole 7 and exposing the peripheral portion of the through-hole 7 and a recording/reproducing opening for the magnetic head to access over the recording track of the disk 2. Starting point detection holes 10 are provided for detecting the starting point of a track in the circumferential direction of the disk 2, thereby determining the starting point of radial movement of the disk 2, and for correctly tracking the magnetic head.

In this way, the rectangular sheet cord 4 with the Kleenige sheet 3 fused to one side is bent along the center bending line 6 with the Kleenige sheet 3 inside, and the magnetic disk 2 is inserted into the formed hollow part. After that, each laminating edge 5.
5' and 5'' are bent and heat-sealed to the outer surface of the other square portion of the sheet element body 4 to make a disk containing the magnetic disk 2.

The magnetic disk coated ridge of the present invention has excellent thermal stability, has low thermal stability such as elongation and warping at high temperatures, stabilizes the recording and playback characteristics of the magnetic disks it accommodates, and has fewer soft errors. has advantages.

e. Example Next, the present invention will be explained in detail with reference to examples.

<Example 1> Polychlorinated polyvinyl chloride (FJT 742 to Nihon Kabai 1) 10
0 parts by weight Carbon black 2 parts by weight Methyl methacrylate-butadiene-styrene copolymer (Kanebuchi Chemical Kane Ace 3-22) 10 parts by weight Stabilizer (dibutyl soot malate type) 1.5 parts by weight Lubricant
A sheet having a thickness of 210 μm was prepared from a composition consisting of a 0.5-weight portion. The sheet was heat treated at 60°C for 20 hours.

A jacket was made using an acrylic nonwoven liner with a modulus of 165 g/cm at 1% elongation.

This product was good, with little deformation of Jackera 1 over the range from 0°C to 60°C, and little occurrence of errors.

Here, a method for evaluating characteristics will be described.

(1) Prepare 20 heat-deformable floppy disks with jackets, and
Place it in a storage case with sheets and stand it upright at 60℃80%R.
Heat treatment was performed for 72 hours in a constant temperature and humidity oven. This processed floppy disk J) 3 C62
Using a drop-through gauge specified in 91, only the slit interval was changed to 2 or 4 urur, and whether or not the sample could pass through the slit was determined. It is expressed as the number of defective sheets that could not pass through the slit out of the 20 sheets tested.

(2) Retry all initialized signals using a 96TPI floppy disk device with a temporary error of 51/4 inches.
ry) The data was read 0 times up to 500 times, and the number of times a CRC error occurred in each sector was counted.

Measurements were made on 10 samples, and the total evaluation was made.

The measurements were conducted in a semi-clean environment under the following two conditions.

Condition A: Measurement at room temperature in high quality condition (23° C. 55% R)-1).

Condition C: Measured at room temperature in fine condition after heat treatment at 60°C for 72 hours. (This was processed under the same conditions as the thermal deformation test described above, and the error rate tends to be higher in the case of jackets that are deformed.) (3) Differential thermal analysis of sheet Maximum endothermic peak temperature Manufactured by Shinku Riko ■, Measurement was performed using a differential scanning calorimeter DSC-1500 at a temperature increase rate of 10° C./min.

(4) Modulus of liner at 1% elongation: 23℃, 5
A tanzak-shaped specimen with a width of 204 mm was cut out parallel to the machine direction from a liner whose humidity was adjusted to 0 to 55% RH, and tested using an Instron type tensile tester with a chuck distance of 100 m.
Measurement was performed at a tensile rate of 50#/min (deformation rate of 50%/min).

The modulus at 1% elongation is expressed by converting the load at 1% elongation into the width 11.

<Example 2.3 and Comparative Example 1.2> Acrylic liners with various moduli at 1% elongation were prepared, and floppy disks were obtained in the same manner as in Example 1. The results are shown in Table 1.

(Space below) Table 1 (Space below) If the modulus of the liner at 1% elongation is too high, the bulkiness of the liner will be lost, resulting in poor cleaning performance and an increased error rate under condition A (Comparative example 2).

On the other hand, if the modulus at 1% elongation is too low (Comparative Example 1 also shows a high error rate under the conditions, this is because the bond between single fibers is insufficient and the fibers tend to fall off, resulting in increased dust generation. Possible causes are that the liner surface is too soft and it is difficult to apply sufficient force to the media for cleaning, but it is not clear.

In Comparative Example 2, the modulus of the liner at 1% elongation was large, so it can be considered that the deformation stress of the liner was transmitted to the sheet surface during the 65° C. treatment, promoting deformation of the di-Vket. Therefore, the error rate under condition C is high.

As described above, the modulus of the liner at 1% elongation is related to important properties such as cleaning properties, dust generation properties, and jacket deformability, and there is an optimal range of the modulus.

A good range is from 50 g/cm to 400 g/cm.

<Example 4 and Comparative Example 3> Liners made of the same acrylic fiber as in Example 1 and liners with different maximum endothermic peaks in differential thermal analysis (DSC) were used.
, 21 #III! Floppy disks were obtained in the same manner as in Example 1 using sheets of various thicknesses.

The results are shown in Table 2.

(The following is a margin) Table 2 (The following is a margin) In order to keep the 60°C thermal deformation defect low and the error rate under condition C low, it is necessary that the sheet OSCI large endothermic peak be high. The temperature is preferably 90°C or higher.

Effects of the present invention After the maximum endothermic peak of DSC is 90'C or more, the chlorinated vinyl chloride sheet has a modulus of 50 to 40 at 1% elongation.
A floppy disk using a jacket consisting of a liner mainly made of polyacrylonitrile fibers of 0.09/cm has low temporary errors and extremely high reliability even when used in any environment.

[Brief explanation of the drawing]

FIG. 1 is a plan view of the jacket of the present invention, and FIG. 2 is a cross-sectional view of the floppy disk with a built-in disk (taken along the line II in FIG. 1). Figure 3 is an exploded view of the jacket. In the drawings, 1 is a jacket sheet, 2 is a flexible disk, and 3 is a cleaning liner.

Claims (1)

[Scope of Claims] 1) A floppy disk consisting of a magnetic disk and a jacket for accommodating the magnetic disk, wherein the jacket is made of a sheet mainly made of post-chlorinated vinyl chloride resin, and the inner side of the sheet is A floppy disk jacket characterized in that the fibrous liner attached to the floppy disk is a nonwoven fabric mainly made of polyacrylonitrile fibers. 2) Modulus of nonwoven fabric mainly composed of polyacrylonitrile fibers at 1% elongation in the machine direction is 400 g/cm or less5
The floppy disk jacket according to claim 1, which has a weight of 0 g/cm or more. 3) The jacket for a floppy disk according to claim 2, wherein the maximum endothermic peak in differential thermal analysis of a sheet mainly made of post-chlorinated vinyl chloride resin is 90° C. or higher.