JPS6216284A - Floppy disk - Google Patents

Abstract

PURPOSE:To stabilize a disk stored to the change of environmental conditions and to minimize the occurrence of the soft error by sticking the unwoven fabric of polyacrylonitrile fiber at the inside of an ABS resin sheet and constituting a jacket. CONSTITUTION:At the inside of a plastic sheet 1 consisting essentially of ABS resin, the unwoven fabric 3 consisting essentially of polyacrylonitrile fiber is stuck as a liner to constitue 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 1% elongation of the machine direction of the unwoven fabric 3, the modulous is 400-50g/cm, and the Vicat softening point of the sheet 1 is >=95 deg.C. 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. Industrial Application Field The present invention relates to a 7P disk, and more specifically to a floppy disk consisting of a flexible disk in which a magnetic deployment medium is formed on a basic film, and a jacket containing the disk. Regarding improved technology.

b. Prior Art With the spread of office automation equipment, floppy disks, which serve as the storage portion of computer processors, 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, floppy disks have been used in a wide range of temperature and humidity conditions such as general office work areas, shops, and homes.
1. It has become common to use them in less clean environments.

It is necessary for floppy disks to operate with high reliability even under such severe conditions, and improving the quality of floppy disks to increase their reliability has become an important issue.

As mentioned above, a floppy disk consists of a flexible disk (hereinafter referred to as a disk), which is a magnetic recording medium punched out in the shape of a disk, and a jacket that encloses the flexible disk. It is lined with a liner that removes dirt.

When the disk rotates, the liner and disk come into moderate contact [-1] The structure is such that foreign matter on the medium is efficiently removed.

By the way, the foreign matter that adheres to the disk is that which enters from the outside through the opening.

There is sand, dust, fibrous garbage, etc.

On the other hand, dust generated from the jacket liner itself and fluff, which is fiber fragments, greatly affect the reliability of the 7P disk. The liner is usually made of a non-woven fabric mainly made of rayon, and this non-woven fabric is manufactured using an adhesive (binder).1. Binder-based non-woven fabrics or binder-based non-woven fabrics that use or do not use a binder (such as spunpond type) to fix the fibers to each other have been mainly used.

Although such rayon-based nonwoven fabrics have relatively good cleaning properties, they have the drawbacks of a large amount of resin powder and fuzz that are separated from the nonwoven fabric, and the problem of large changes in physical properties due to humidity, which is a problem unique to recycled cellulose fibers.

In addition, immediately after the jacket is manufactured, it has a shape that shows good cleaning properties, but as it is subjected to changes in temperature and humidity, its shape changes and the jacket is deformed to a state where cleaning properties are not good. It often appears.

C. Purpose of the present invention The present invention was made in view of the above points, and as a result of conducting studies to improve the reliability of floppy disks, it has been made possible to provide a jacket structure with fewer errors even under fluctuations in environmental conditions. be.

d1 Structure of the Invention The present invention relates to a floppy disk, and particularly to a jacket for housing the disk, and particularly to an improved jacket that can cope with environmental changes. This jacket is made of a plastic sheet whose main component is ABS resin (acrylonitrile-butadiene-styrene copolymer resin), and a fibrous sheet whose main component is poly7 clear resin attached to the inside (disk side). It is made of a composite material consisting of a liner (acrylic nonwoven fabric liner) and has a predetermined opening.

The improvements of the present invention can be summarized in the following three points.

Firstly, by using a jacket sheet made of ABS resin as its main component, the heat resistance of the case was increased and the jacket was made less susceptible to deformation due to changes in usage environmental conditions. 2. The use of an acrylic fiber liner as the liner to be attached to the jacket sheet makes it wider (compared to the conventional rayon-based liner).

To reduce dimensional changes due to temperature and humidity, and to maintain good contact between the disk and the liner under various conditions; TS3 is a nonwoven fabric made of acrylic fiber, and when stretched by 1 inch. Non-woven fabrics with a modulus within a specific range are good at trapping dirt and
Findings include the fact that the liner has retention properties, and the cleaning properties of the liner are improved.

The jacket sheet uses ABS resin.

ABSm resin is composed of three types of monomers: styrene, acrylonitrile, and butadiene, and is generally made of rubber made by homopolymerizing getadiene (PBR) or rubber made by copolymerizing butadiene with styrene or acrylonitrile (SB).
(R or NBR) and (2) a copolymer resin of styrene and acrylonitrile. The ABS resin used in the present invention preferably has a high Hikat softening point and low thermal deformability. On the other hand, brittle materials that cause cranking during the bending process during jacket molding or cracks during low-temperature impact tests are undesirable, and an appropriate balance with the rubber component is required. For the purpose of improving heat resistance and imparting flame retardance to ABS resin, it is also possible to mix one or more of the following polymers at a weight ratio of 50% or less. That is, homopolymers of α-methylstyrene or copolymers of α-methylstyrene (or p-methylstyrene) with methacrylic acid methyl ester, maleic anhydride, maleimide compounds, etc., polycarbonate resins, As resins, AASAs resins. BS resin, AgS resin, AC3 resin, vinyl chloride resin, vinylidene chloride resin,
These include post-chlorinated vinyl chloride resin, vinyl chloride/hinyl acetate copolymer resin, etc. Additionally, a modifier and a small amount of synthetic rubber may be added.

Furthermore, colorants and I-' (carbon black, pigments, etc.) and additives such as stabilizers, flame retardants, lubricants, antistatic agents, etc. may be added.

Conventionally, sheets made mainly of vinyl chloride have been used as sheets for jackets, but these can cause deformations such as bulging and curling of the jacket when exposed to high temperatures (e.g., 50 to 60 degrees Celsius). In this case, the contact between the liner and the built-in disk often results in poor pressure, causing soft errors.These thermal deformations are caused by the ABS of the present invention.
By using a sheet made of resin as a jacket material and combining it with a liner described below, it can be greatly improved. The liner material used in the present invention is #Ji! whose main component is polyacrylonitrile. Made of nonwoven fabric using m, thickness 202/d load) is 0.13 to 0.30
It belongs to m. The fibrous material constituting the nonwoven fabric may include a small amount of thermoplastic fibers such as polyester fibers and polyolefin fibers in addition to the main component, poly7crylonitrile fibers. Further, as a fiber modifier, for example, an oil agent or a surfactant may be included.

In order to suppress deformation of the jacket when changes in temperature and humidity occur, it is desirable to set the modulus of the liner to be low. This is because deformation stress when the liner expands and contracts due to changes in environmental conditions is transmitted to the bonded plastic sheet by means such as heating, promoting deformation of the sheet.
This is to keep the stress level low.The effect on the sheet is more pronounced at high temperatures of 50 to 70℃ than at room temperature.For this reason, the modulus of the liner at 1% elongation in the machine direction is 4.
It is desirable that it is 005F/cry+ or less.

Thermal shrinkage of the liner itself due to residual stress during nonwoven fabric production also contributes to the deformation of the jacket, but this can be improved by pre-treating the liner prior to the lamination process or by selecting lamination conditions.

If the 1 timidulus of the liner is too low, the handling properties during the lamination process will be poor, and one-sided elongation will occur due to pull-up tension and the like. Also, the cause is unknown, but! It has been found that if the timidulus is too low, the cleaning performance also decreases.

Therefore, it is desirable to have a modulus at one inch extension of 50 f/cm or more in order to maintain good leaning properties and workability.

The magnetic disk cartridge of the present invention is characterized in that it is made of the above-mentioned ABS sheet and a liner made of acrylic fiber, and its structure can be of any known structure.

This structure is illustrated in FIGS. 1 to 3 at °C.

The magnetic disk cartridge l is usually lined with a cleaning sheet 3 and has a structure that forms a space for rotatably housing the magnetic disk 2 punched out in a donut shape, and has three bonding edges 5 on one side. ．． 5', 5"
A rectangular sheet material 4 having a shape is folded from the center (broken line 6) to make a shape. The cleaning sheet 3 is made of nonwoven fabric or the like, and is fixed to the sheet material 4 by partially heat-sealing it. This cleaning sheet 3 comes to be interposed between the magnetic disk 2 and the cartridge 10.

The magnetic disk 2 is formed by forming a magnetic recording layer on one or both sides of a flexible and elastic base film made of synthetic resin such as polyester film.1. It is usually punched 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 width 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 70 and a recording trunk for the magnetic head to access are connected to the recording trunk of the disk 2. A playback aperture 9 and a start point detection hole 10 are provided for detecting the start point of a track in the circumferential direction of the disk 2, thereby determining the start point of radial movement of the disk 2, and for correctly tracking the magnetic head. There is.

In this way, the rectangular sheet body 4 with the cleaning sheet 3 fused on one side is bent along the center bending line 6 with the cleaning sheet 3 inside, and the magnetic disk 2 is inserted into the formed hollow part (7). Then, each bonding edge 5, 5', 5' is bent and heat-sealed (7) to the outer surface of the square portion of the pond of the sheet body 4 to make a disk containing the magnetic disk 2. The magnetic disk cartridge of the present invention has excellent thermal stability, and has little thermal deformation such as elongation or warping at high temperatures.Also, the expansion and contraction of the liner material due to humidity is small, making it easy to record and store magnetic disks.
This has the advantage that the reproduction characteristics are stabilized and there are fewer soft errors.

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

<Example 1> ABS resin (Cycolac GSE manufactured by Ube Cycon ■)
100 parts by weight carbon blank 2 Lubricant
0.5 l stabilizer
0.2 from a composition consisting of 1
A sheet with a thickness of 1 m was made using an extrusion method. This sheet was heat treated at 65° C. for 20 hours. The Vicat softening point of this sheet was 107°C. This sea) K1%1%
An acrylic non-woven fabric liner of 165 f/cm was attached to the elongated durus [-1] to create a jacket by bending and punching the opening.Next, a flexible disk was inserted, further bending was done, and a floppy disk was created. Got the disc.

Comparative Example 1 A 0.21 m thick vinyl chloride sheet for commercially available floppy disks containing vinyl chloride homopolymer as the main component,
Commercially available rayon and polypropylene fibers with a thickness of 0.
1. in the same manner as in Example 1 using a liner with a modulus of 15027 (7) at 1% elongation at 25 m. I got a floppy disk.

Comparative Example 2 Using the same vinyl chloride sheet as in Comparative Example 1 and the same nonwoven fabric made of acrylic fiber as in Example 1, a floppy disk was obtained in the same manner as in Utility Model No. 1.

Comparative Example 3 Using the same ABS resin sheet as in Example 1 and the same liner made of rayon/polypropylene fiber as in Comparative Example 1, a °C floppy disk was obtained in the same manner as in Example 1.

Above is the example 1. Table 1 shows the results of the thermal deformability of the floppy disks obtained in Comparative Examples 1, 2.3, and the temporary errors related to the reliability of reading the serial number. Incidentally, the temporary error was measured under the following three conditions in consideration of various usage environments of the floppy disk.

Moxibustion condition A: Measurement at room temperature and humidity (23℃, 55% RH), East condition B: Measurement condition at low humidity (23℃, 15-20℃RH) Condition C: Measurement at room temperature and humidity after heat treatment at 65℃ for 72 hours. (It was processed under the same conditions as the thermal deformation test described later.) In the case of jackets that have deformed, the error rate tends to be high (Table 1) In Comparative Examples 1 and 2, Because the deformation is large, the jacket deforms at 65°C, and therefore the error rate under condition C also increases (increases).On the other hand, in Comparative Example 3, the thermal deformability of the jacket is small and good, but the cleaning performance of the liner is The temporary error of condition A, which is determined by the balance of dust generation of the liner itself, is large (and the change when condition B is reached is also large).

On the other hand, in Example 1, the errors under condition A were small, probably because the liner had excellent cleaning properties and dust-generating properties, and the errors under condition B were also small, probably because the expansion and contraction due to humidity changes was small. In addition, since the sheet has good heat resistance, there is no defective jacket deformation, and furthermore, errors under condition C do not increase.

In addition, the evaluation method in the above evaluation is described in degrees Celsius.

20 heat-deformable footspee disks of mountain jackets were prepared, and each 10 disks were placed in a "storage case containing 10 disks" and stood upright, and heat treated for 72 hours at 65° C. and 80 φRH in a constant temperature constant fi open.

This processed floppy disk JISC6291
Using a drop-through gauge specified by , only the slit interval was changed to 2.4 wm to determine whether or not the sample could pass through the slit.

In test J, out of 20 sheets, the number of defective sheets that passed through the slit was expressed as the number of sheets that did not pass through the slit.

(2) Retry all initialized signals using a 967PI FTP disk device with a temporary error of 5↓ inches.
Reading was repeated up to 500 times, and the number of occurrences of CRC errors in each sector was counted. Ten samples were measured and evaluated based on the total number of readings.

Note that the measurements were performed in a semi-clean environment.

(3) Vicat softening point AST of plastic sheet
In accordance with M D 1525, the samples were stacked so that the thickness of the samples was 3, the needle diameter was 1, the load was IKg, and the temperature was increased at a rate of 50° C./hour.

(4) Modulus of liner when stretched by 1 inch: 23℃50
A 20°C wide tanzak-shaped specimen was cut out from the ~55mm RHK humidity conditioned liner parallel to the machine direction, and tested using an in-stone tensile tester at a distance of 100m between chucks and a tensile speed of 50 ma for 7 minutes (deformation speed of 50%/ (measurement atmosphere: 23°C, 50% to 55% RH'). The modulus when one inch is extended is expressed by converting the load when one inch is expanded into a width of 1α17.

Examples 2 and 3 and Comparative Example 4.5> Next, the effect of monyrus upon 1% elongation of the nonwoven fabric made of acrylic fibers was investigated.

The same ABS resin sheet as in Example 1 was used, and a nonwoven fabric made of acrylic fiber was used with various σs having different 1-inch elongation modulus.
) A floppy disk was obtained in the same manner as in Example 1 using a liner. The results are shown in Table 2.

Table 2 If the modulus of the liner during 1-inch elongation is too high, the liner loses its bulkiness, resulting in poor cleaning performance and an increased error rate under condition A (Comparative Example 5). On the other hand, even when the error rate is too low (Comparative Example 4), a high error rate is shown under condition A, but this is because the bond between single fibers is insufficient and the fibers tend to fall off, which increases dust generation, or because the liner The possible cause is that the surface is too soft and sufficient force for cleaning is applied to the media, but it is not clear.

In Comparative Example 5, since the liner had a large modulus upon elongation, 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 jacket. Therefore, the error rate under condition C is high (
I'm here.

As described above, there is an optimal range of modulus in relation to important properties such as cleaning properties, dust generation properties, and jacket deformability. A good range of this modulus is from 501/(7) to 400 f/cm.

<Examples 4 and 5 and Comparative Example 6> Furthermore, the heat deformation resistance of the ABS 41 resin sheet was investigated. A liner made of the same acrylic fiber as in Example 1,
ABS Net and [7] Vicat softening points are different from 0 and 21.
Floppy disks were obtained in the same manner as in Example 1 using various sheets having a thickness of trvn.

The results are shown in Table 3.

Table 3 These results show that it is necessary to use an ABS sheet with a Vicat softening point of 95° C. or higher in order to suppress thermal deformation defects at 65° C. and keep the error rate low under Condition C.

f. Effects of the present invention Using a jacket consisting of an ABS sheet with a Vicat softening point of 95°C or higher and a liner mainly made of polyacrylonitrile fibers with a modulus of 50 to 40,017 cm when stretched, the p-tup disk can be used in any environment. It also has low temporary errors and extremely high reliability.

[Brief explanation of drawings]

FIG. 1 is a plan view of the floppy disk of the present invention, and FIG. 2 is a sectional view taken along arrow I-1 in FIG. Also the third
The figure is a developed view of the jacket part.

Claims (1)

[Claims] 1) A floppy disk consisting of a flexible magnetic recording disk and a jacket containing the disk, the jacket consisting of a plastic sheet and a liner made of a fiber material, the plastic sheet being AB
A floppy disk characterized in that it is a sheet mainly made of S resin, and the liner is a nonwoven fabric mainly made of polyacrylonitrile fibers. 2) The floppy disk according to claim 1, wherein the nonwoven fabric mainly composed of polyacrylonitrile fibers has a modulus at 1% elongation in the machine direction of 400 g/cm or less and 50 g/cm or more. 3) ASTM D152 for sheets mainly made of ABS resin
3. The floppy disk according to claim 1 or 2, wherein the floppy disk has a Vicat softening point of 95° C. or higher as determined by the measurement method of Item 5.