JP2761395B2 - floppy disk - Google Patents

Description

Description: BACKGROUND OF THE INVENTION The present invention relates to a floppy disk excellent in various performances such as media durability and a media error rate.

[Conventional technology]

A conventional floppy disk, as shown in FIG.
A magnetic layer is provided on a disk-shaped non-magnetic support, comprising a magnetic disk medium 1 having a lubricant on the surface of the magnetic layer, and a jacket 5 surrounding the magnetic disk medium. 4 is attached. The magnetic disk medium 1 is fixed by a hub 2. Liner 3,
Reference numeral 4 denotes a cut-out portion 7 opposed to a rectangular opening 6 for bringing the magnetic head into contact with the magnetic disk medium 1.
The facing surface of the magnetic disk medium 1 is covered (for example, JP-A-61-253682, JP-A-62-51027).

[Problems to be solved by the invention]

However, in conventional floppy disks, no matter how the material of the non-woven fabric that is the liner is selected, the non-woven fabric has a capillary action, so that the transfer of the lubricant from the magnetic layer of the magnetic disk medium to the liner is prevented or the transfer speed is reduced. Was difficult to lower. As a result, the lubricant is quickly lost from the magnetic layer, and the running of the floppy disk wears the magnetic layer, resulting in a decrease in media durability of the floppy disk.

An object of the present invention is to provide an economical floppy disk which is excellent in durability and economical.

[Means for solving the problem]

According to the present invention, a magnetic disk medium 1 having a magnetic layer provided on one or both surfaces of a disc-shaped nonmagnetic support and having a lubricant on the surface of the magnetic layer, and liners 3, 4 capable of contacting the surface of the magnetic layer And a jacket 5 provided on the inner surface thereof, wherein the liners 3, 4 are made of an oil-repellent nonwoven fabric. In another aspect, in the floppy disk, the oil-repellent nonwoven fabric has a perfluoroalkyl group-containing acrylic polymer coating, a nonwoven fabric having a perfluoroalkyl group-containing urethane oligomer coating, and a perfluoroorganic acid coating. What is provided is a nonwoven or a nonwoven having a metal salt coating of a perfluoroorganic acid.

FIG. 1 is an exploded perspective view of a floppy disk according to one embodiment of the present invention. Referring to FIG. 1, the floppy disk of the present invention is constructed by covering a magnetic disk medium 1 with a jacket 5. Liners 3 and 4 which are in contact with the surface of the magnetic disk medium 1 are mounted on the inner surface of the lifter portion of the jacket 5, and a hub 2 for fixing the liner is provided at the center of the magnetic disk medium 1. The rectangular opening 6 is provided for bringing the magnetic head into contact with the magnetic disk medium 1.

The magnetic disk medium 1 has a magnetic layer provided on both surfaces of a base material such as a polymer film, and a lubricant is held on both surfaces. The lubricant prevents wear of the magnetic layer at the contact portion between the magnetic head and the magnetic layer during running of the floppy disk, thereby improving the durability of the floppy disk. For this reason, it is preferable that the lubricant is stably present as a liquid under the use environment (0 to 60 ° C.) and is hardly affected by physical and chemical influences such as adsorption and decomposition in the magnetic layer. Lubricants that can be used for this purpose include alcohols, silicone oils, higher fatty acids, paraffinic hydrocarbons, fatty acid esters, glycerin esters, perfluoroalkyl ethers, perfluorofatty acid esters,
Examples thereof include silicate esters, phosphate esters, and polyglycols. In the present invention, in particular, the following general formula: In the above formula, R _{1 to} R ₄ each independently represent a C _{1 to} C ₂₂ alkyl group.

Liners 3, 4 in floppy disk of the present invention
An oil-repellent non-woven fabric is a non-woven fabric having a property to repel the lubricant. The oil-repellent nonwoven fabric in the present invention is, for example, a spray coating of an oil-repellent solution onto any known nonwoven fabric 9 such as a rayon-based, polyethylene terephthalate-based, nylon-based, acrylic-based or non-woven fabric of these blended yarns. An oil repellent coating 8 is provided by a method such as immersion of the nonwoven fabric to reduce the surface tension of the nonwoven fabric. The critical surface tension of the known nonwoven fabric is about 40 to 45 dyne / cm ² , whereas the nonwoven fabric having the oleophobic coating of the present invention has a critical surface tension of about 20 dyne / cm ² or less. Here, for reference, the critical surface tension of the nonwoven fabric, that is, the surface energy of the plastic, was measured by measuring the contact angle θ of a solid surface on which a plurality of liquid droplets of known surface tension were to be measured. From the straight line obtained by plotting a series of values, the surface tension at which the contact angle O is determined is determined. This is called the critical surface pressure γσ, which is estimated as the surface energy of the solid. (For details, see Kiyoshi Matsubara, "Tribology", Sangyo Tosho Publishing Co., Ltd., 1981, 106
In the present invention, examples of the oil repellent used for the oil repellent treatment of the nonwoven fabric include the formula (A): (Wherein R ₁ and R ₂ are each independently a hydrogen atom or a methyl group, and n is an integer of 7 to 13), and a perfluoroalkyl group-containing acryl having a molecular weight of 10,000 to 20,000 -Based polymer, (b) polyfunctional isocyanate such as tolylene diisocyanate, hexamethylene diisocyanate and the formula: CnF ₂ n + ₁ SO ₂ NH—CH ₂ CH ₂ OH (wherein n
Is an integer of 7 to 13), a compound represented by the formula: (Where n is an integer of 7 to 13) a perfluoroalkyl group-containing urethane oligomer which is a condensed compound with a perfluoroalkyl group-containing compound such as a compound represented by the formula:
(C) A perfluorocarboxylic acid represented by the formula: CnF ₂ n + ₁ (CH ₂ ) _m COOH (where n is an integer of 7 to 13 and m is an integer of 2 to 6) (D) fluorobutyric acid, perfluorolauric acid) or (d) salts (including complex salts) of the perfluorocarboxylic acids with metals such as zinc and zirconium. That is, the oil repellent in the present invention has a surface tension lower than the surface tension of the lubricant (specifically, a critical surface tension: 15 dyne / cm ² or less), and thus has a property of repelling the lubricant. .

[Action]

The liner of the present invention is made of an oil-repellent nonwoven fabric, unlike a liner made of a conventional nonwoven fabric. In the conventional liner, the lubricant is transferred to the nonwoven fabric as the running time of the floppy disk elapses due to the capillary action existing in the gap of the nonwoven fabric. Since the surface tension of the nonwoven fabric of the liner of the present invention is lower than that of the conventional liner, the capillary action is inhibited, and the transfer of the lubricant to the nonwoven fabric is prevented or reduced. Therefore, the lubricating effect of the lubricant on the surface of the magnetic disk medium is remarkably long. Moreover, the liner of the present invention does not lose its original effect of preventing charging of the surface of the magnetic disk medium and cleaning the surface.

〔Example〕

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these Examples.

Examples 1 to 6 and Comparative Examples 1 to 4 Cobalt-containing γ-iron oxide 100 parts by weight Carbon black 15 Alumina 10 Nitrocellulose (RSI manufactured by Daicel) 16 Polyurethane (HI-2000 manufactured by Dainippon Ink) 14 Lubricant 12 Polyisocyanate (Coronate L manufactured by Nippon Polyurethane Co., Ltd.) 8 Cyclohexane 200 Methylethylketone 200 A magnetic paint having the above composition was prepared. Thick this 75
μm polyethylene terephthalate film applied on both sides, after sufficient drying, calendering, thickness 1.0 ~
A film having a 1.3 μm magnetic layer was obtained. This was left in an oven at 60 ° C. for 2 days, and then punched and polished into a disk to produce a magnetic disk medium.

Further, on the inner surface side of Jiyaketsuto of ABS resin having a lifter portion, and spray coating the solution oil repellent as oil repellent about 80mg is coated as about 0.1~0.3mm nonwoven 1 cm ² per solid thick fraction The formed oil-repellent nonwoven fabric was stuck. The magnetic disk medium was loaded into this jacket to produce a 3.5 ″ floppy disk.

On the other hand, for comparison, in the same manner as above except that a non-woven fabric having no oil repellent coating was used as a liner.
5 "floppy disk was manufactured.

For these floppy disks, (1) tensile strength (kg / cm ² ) in the vertical direction of the liner, (2) oil repellency of the liner, (3) transfer rate of lubricant to the liner (%), (4) )
The media durability (10,000 passes) and (5) the media error occurrence rate (%) were measured. Here, the oil repellency of the liner (2) was determined by dropping one drop (0.05 to 0.1 ml) of the lubricant on the liner placed horizontally and visually determining the wetness of the liner after about 1 minute ( ：: The lubricant droplets did not seep into the liner at all, and no bleeding was observed. ×: The lubricant droplets completely or partially soaked into the liner, and the area around the droplets was seen to bleed. The transfer rate (%) of the lubricant to the liner in the above (3) was obtained by quantifying the transfer amount of the lubricant to the liner after 15 million passes by gas chromatography and calculating the ratio to the initial value.
The media durability (10,000 passes) of (4) was determined by measuring the number of passes until the magnetic layer was worn. The media error occurrence rate (%) of (5) is 40 ° C. and relative humidity 80% RH.
After storing for 3 days, the number of signals initially recorded was counted by an actual machine.

 The results are shown in Table 1 on the next page.

In addition, the formula (1) of the urethane oligomer: As shown in Table 1, the liner in the floppy disk of the present invention is oil-repellent unlike the liner in the floppy disk of Comparative Example, so that the transfer rate to the lubricant to the liner is low, and the liner in the vertical direction Since the tensile strength is also good, the media durability of the floppy disk of the present invention is 30 million passes or more, which is practically sufficient. Moreover, the floppy disk of the present invention does not cause any media error.

In the floppy disk of the present invention, Scotchgard FC-905 manufactured by Sumitomo 3M Co., Ltd. has a strong bonding force to a rayon-based nonwoven fabric and is particularly preferable.

〔The invention's effect〕

As described above, according to the present invention, it is possible to provide a floppy disk which is remarkably excellent in various performances such as a media durability and a media error occurrence rate, and has drastically improved its practical value.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view of a floppy disk according to one embodiment of the present invention. FIG. 2 is an exploded perspective view of a conventional floppy disk. DESCRIPTION OF SYMBOLS 1 ... Magnetic disk medium 2 ... Hubs 3 and 4 ... Liner 5 ... Jacket 6 ... Opening 7 ... Notch 8 ... Oil-repellent treated surface

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) G11B 23/033

Claims (2)

(57) [Claims] 1. A magnetic disk medium having a magnetic layer provided on one or both surfaces of a disc-shaped non-magnetic support and having a lubricant on the surface of the magnetic layer, and a liner capable of contacting the surface of the magnetic layer are provided on the inner surface. A floppy disk comprising a jacket, wherein the liner is made of an oil-repellent nonwoven fabric having a surface tension of 20 dyne / cm ² or less. 2. The non-woven fabric having a perfluoroalkyl group-containing acrylic polymer coating, a non-woven fabric having a perfluoroalkyl group-containing urethane oligomer coating, a non-woven fabric having a perfluorocarboxylic acid coating, or a perfluorocarboxylic acid-containing non-woven fabric. The floppy disk according to claim 1, which is a nonwoven fabric having a metal salt coating.