JPH0469878A - Floppy disk - Google Patents

Abstract

PURPOSE:To prevent the occurrence of drop-out at the time of recording and reproducing by using a specific material as a liner. CONSTITUTION:A web made of a rayon fibers and thermoplastic fibers having 100 to 300 deg.C fusing point has thermoplastic fibers f;used by heating practically under no pressing force to adhere the intersections of rayon fibers, and at least a lifter contact part of the liner arranged on the jacket side provided with a lifter is made of a nonwoven fabric obtained in this manner. This web are partially press-fitted by heat at a temperature higher than the fusing point of thermoplastic fibers to form recessed parts on the web surface, and a liner aragned on the jacket side where the lifter is not provided is made of a nonwoven fabric obtained this manner.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a floppy disk. More specifically, the present invention relates to a high-density magnetic recording medium manufactured by vacuum evaporation, sputtering, etc., and a floppy disk using a liner that significantly improves its durability.

[Prior Art] Generally, as shown in the figure, a floppy disk includes a flexible disk-shaped magnetic recording medium 3 and a liner 2.
It has a structure in which it is housed in a jacket 1.4 made of synthetic resin such as vinyl chloride via a cable 5. Reference numeral 6 denotes a lifter made of plastic film, metal foil, etc. provided on the inner surface of the jacket 4 on one side, and serves to lightly press the liner against the surface of the disk-shaped magnetic recording medium. The functions required of this liner are high lubricity to the disk and good disk surface cleaning properties.

Conventionally, ribbons for floppy disks are made by partially thermocompressing a web made of rayon fibers and thermoplastic fibers such as polypropylene, polyester, nylon, or acrylic fibers using Gombosca L/N. C is used. In this thermocompression bonded section, the molten thermo-I-replastic fibers bind the rayon fibers in an adhesive structure 17 to form four parts. - On the other hand, in addition to the conventional coating type, magnetic recording media have recently been developed using vacuum evaporation and
High-density thin-film magnetic recording media manufactured by sputtering methods are actively being developed.

[Problem to be solved by the invention 2] When a conventional liner is applied to a disk-shaped magnetic recording medium manufactured by vacuum evaporation method or sputtering method, C
The drawback is that part of the liner adheres to the surface of the disk-shaped magnetic recording medium, significantly reducing wear resistance and preventing smooth rotation. Detailed information on the liners of these floppy disks 2. Upon inspection, it was found that the plastic fibers in the area pressed against the surface of the disk-shaped magnetic recording medium by the lifter were damaged by the heat. Thin film magnetic recording layers are laminated 1 and Σ゛isk-shaped magnetic recording media (4).Since the surface has poor slipperiness compared to conventional coated media, the thermoplastic fibers soften due to frictional heat from the media;
(1) is melted and (2) the surface of the disk-shaped magnetic recording medium)
This is thought to be because of this. The object of the present invention is to solve these drawbacks, provide a floppy disk with excellent durability, a liner with good cleaning properties, and excellent abrasion resistance.
do.

[Means for Solving the Problems] That is, the present invention laminates thin film magnetic recording layers on both sides of a base film, and connects a disk-shaped magnetic recording medium to both sides of the medium with Rhino. In a floppy disk comprising a jacket with a lifter, at least the lifter contacting part of the liner placed on the jacket side having a lifter is constituted by a liner made of the following A, and the liner placed on the jacket side without a lifter is The floppy disk is characterized in that the liner is made up of at least 1-' B liner.

A: Rayon fiber and heat iiJ with a melting point of 100-300℃
The web made of plastic fibers is heated to i1 under substantially no pressure.
1) A nonwoven fabric made by bonding the intersection points of the rayon fibers by heating and melting the plastic fibers; It is a non-woven fabric having four parts on the web surface by partially thermo-compression bonding at a temperature above the softening point of the fibers.

As the base film used in the present invention, any known base film can be used. Examples include films made of biaxially stretched polyester, polyphenylene sulfide, aromatic polyamide, polyimide, and the like.

In addition, PACE FILNO's 170 is not particularly limited, but in terms of dimensional stability and mechanical properties, it is better than 10 to 500 l.
The range is preferably 1 m, more preferably 25 to 200 m.
μ■η, more preferable (1, preferably 30 to 75I1m)
, furthermore, the base film is coated prior to the formation of the magnetic layer.
Various surface treatments and pre-treatments such as facilitating adhesion, improving flatness, coloring, imparting anti-static properties and abrasion resistance may be applied.

In the present invention, any known thin film magnetic recording layer can be used to be formed on both sides of the base film.

For example, Co-Ni, Co-NiCr, Co-Ni-F
There are longitudinal recording layers such as e-Cr, partial oxide films of Co, Ni, and Fe, and perpendicular magnetic recording layers such as Co-Cr.
It is formed by a vacuum evaporation method or a sputtering method. Among these, one of the most remarkable effects of the present invention is a perpendicular magnetic material made of cobalt and its partial oxide obtained by a reactive vapor deposition method by introducing oxygen gas and a gas with low chemical activity. An example is one in which seven recording layers are laminated. In particular, electron beam evaporation is most suitable in order to have excellent and stable magnetic properties such as coercive force and anisotropic magnetic field, and to stably obtain a high crotch forming speed.

Next, an outline of the manufacturing method will be explained using an electron beam evaporation method as an example.

That is, a vacuum chamber is provided with a traveling system having an unwinding shaft for feeding out a long base film, a cylindrical base film support drum, a base film winding shaft, etc., and after being evacuated from an exhaust port, chemical activation is performed. Cobalt is evaporated using an electron beam evaporator while introducing a mixed gas of a small gas and oxygen gas, and oxygen gas.
X10-'Torr~, 5X1.0-2Torr
It can be obtained by depositing a perpendicularly magnetized film mainly made of cobalt and its partial oxide to a predetermined thickness at a predetermined deposition rate on a base film running at a predetermined speed on a drum at a pressure of . Gases with low chemical activity include nitrogen, argon, helium, etc.
The evaporation material is mainly cobalt, which is a ferromagnetic material, but iron, nickel, etc. may be added in order to adjust magnetic property values or improve corrosion resistance, wear resistance, etc. In this way, magnetic layers are laminated on both sides of the base film.

Note that the thickness of the magnetic layer is not particularly limited, but is practically in the range of 0.02 to 5 μm, taking into consideration flexibility, contact with the magnetic head, and film formation speed of the magnetic layer. In this case, a range of 0.05 to 2.0 μm is desirable. Furthermore, it is preferable to laminate a protective layer and a lubricating layer on the magnetic layer. As the protective layer, known materials such as SiO2 and carbon can be used, but carbon, which also has lubricity, is particularly preferred. Further, as the lubricant layer, a fluorine-based lubricant or the like is preferable.

Thin film magnetic recording media are used after being punched into the shape of a floppy disk of a predetermined size.

Although the basic structure of the floppy disk of the present invention is the same as that of the conventional one, it is important to place a liner having a specific configuration in a specific position.

In other words, the entire liner 5 located on the jacket 4 side or at least the portion in contact with the lifter 6 is A, which will be described later.
It is preferable that all or a part of the liner 2 located on the jacket 1 side, preferably the part other than the part facing the lifter 4, be made of a liner made of B.

Liner A is rayon fiber and has a melting point of 100 to 300°C.
A web well mixed with thermoplastic fibers is heated at a temperature above the melting point of the thermoplastic fibers and below the melting point of the rayon fibers under substantially no pressing pressure to melt only the thermoplastic fibers and aggregate them at the intersections of the rayon fibers. , is a nonwoven fabric with the intersection points bonded together. At this time, it is necessary that the rayon fiber maintains its fiber form. Here, heat treatment under substantially no pressure refers to heat treatment using hot air, radiant heat, or the like, with little pressure applied to the web, and it is preferable to uniformly heat the entire web to the inside. As thermoplastic fibers, polyethylene, polypropylene, polyester, nylon fibers, etc. can be suitably used. It is preferable that the thermoplastic fibers are contained in the web in an amount of 5 to 70% by weight, more preferably 10 to 50% by weight, still more preferably 15 to 70% by weight.
The amount is 30% by weight, and if the amount of the thermoplastic fiber is less than this, a nonwoven fabric cannot be formed, whereas if it is more than this, cushioning properties and flexibility are lost, which is not preferable.

When Liner A is used, there is virtually no contact between the thermoplastic fibers and the disc-shaped thin film magnetic recording medium, and damage to the thermoplastic fibers that occurs in the prior art can be significantly reduced.

Liner B is rayon fiber and has a melting point of 100 to 300°C.
A web made of thermoplastic fibers is pressed against an embossing roll at a temperature higher than the softening point of the thermoplastic fibers, preferably higher than the melting point, and the thermoplastic fibers are bonded by thermocompression, thereby bonding the rayon fibers together at the thermocompression bonding part. It is a nonwoven fabric obtained by adhering. This thermocompression bonding is formed in a predetermined shape so as to be distributed at appropriate intervals on the web. The ratio of the area of the thermocompression bonded part to the web is 10 to 4
It is preferably 5%, more preferably 20-35%. Moreover, the linear pressure of the embossing calender is preferably in the range of 5 to 30 kg/m. This thermocompression bonding part is created by the softened or melted thermoplastic fibers contributing to adhesion of the rayon fibers to obtain a strong bond and forming four parts.
7. Excellent collection effect. do. Therefore, at least the liner B is preferably formed on all or part of the liner that does not have a lifter, where it is difficult to collect dust, etc., preferably on a portion other than the portion facing the lifter 4.

The proportion of the liner 3 in the liner 2 on the side without the knotter is preferably 25% or more, more preferably 50% or more in terms of area ratio. If liner B is placed on the side that does not have a lifter, for example, liner 8 may be placed on the remaining portion, but in that case, with the disk-shaped magnetic recording medium in between, It is preferable to arrange the liner A on the opposite side of the lifter part. This is thought to be because the leveler and the disk-shaped magnetic recording medium come into rather strong contact with other parts due to the pressure of the lifter even on the side that does not have a lifter.

On the other hand, if the liner B is provided at the lifter contact portion of the liner 5 on the side having the lifter, the wear resistance will be significantly lowered. This is thought to be because, as described above, the thermoplastic fibers of liner B were softened or melted by frictional heat with the disk-shaped magnetic recording medium and adhered to the surface of the medium. 1. The basis weight of the liners A and B used in the present invention is not particularly limited, but is 10 to 1. , 5 Og/%, more preferably 15 to 75 g/M1, still more preferably 20 to 50 g/M1. Thickness is O, 5n
]nn or less, preferably 0. 4TT11T1 t',
More preferably [7 is O, 3 nm or more F]. If the filtration density (defined as 10-3X basis weight [g/n(] / thickness [mm]: g/cm') is less than 0.02 g/cm', foreign matter, dust, etc. may occur due to large voids. The collection efficiency is poor, and the collected foreign matter, dust, etc. will be scattered again and re-contaminate the magnetic disk surface.
If the thickness exceeds 5mm, foreign matter, dust, etc. will not enter, which will also result in poor collection efficiency, and if the thickness exceeds Q, 5mm, the frictional force with the magnetic disk will increase and the rotational torque will decrease. This may cause lifting or uneven rotation.

Further, an appropriate amount of an oil agent used in a spinning process or a carding process during nonwoven fabric production may be added to the liner.

As the material of the lifter, plastic film such as polyester film or metal foil such as stainless steel is preferably used. In the case of polyester film, the thickness is 50 to 200 μm, preferably 75 to 175 μm, more preferably 100 to 150 μm, and in the case of stainless steel, it is 20 to 100 μm, preferably 30 to 80 μm.
m1 is more preferably 40 to 60 μm. The shape is 3
゜For a 5-inch floppy disk, the width is 25rnm.

A rectangular one with a length of about 20 mm is preferably used,
1-15° to the jacket, preferably 2-10°
, more preferably provided on one side of the jacket at an angle of 3 to 7.5 degrees by heat sealing, adhesive or pressure-sensitive adhesive.

``Characteristics measurement method, evaluation criteria (1) Abrasion resistance test method A thin film magnetic recording medium was punched out in the shape of a 3.5 inch floppy disk and placed in a jacket. ) FD10
35), the same track was run, and the reproduced signal was recorded on recording paper. The running rotational speed (pass) until the reproduction signal became 70% or less was defined as the wear resistance. Note that the rotation speed of the floppy disk is 300 revolutions per minute.

[Example J The effects of the present invention will be specifically explained using examples.

Example 1, Comparative Example 1.2 This polyester film was placed in the long base film running system of an electron beam evaporator (=J), the vacuum chamber was evacuated from the exhaust port, and the pressure near the evaporation zone was 5
It was evacuated until the temperature was below rt.

Next, a mixed gas of oxygen:nitrogen-10:90 (volume ratio) was introduced into the vicinity of the upstream side of the base film running direction through the introduction pipe at a flow rate of 0°6 (1/m1n). Further, oxygen gas was introduced from near the downstream toward the evaporation source at a flow rate of 0°1 (1/rruin). After achieving this state, the polyester film was run, and an alloy consisting of Co:Ni:Fe=90:5:5 was melted and evaporated onto the base film using an electron beam evaporator at a pressure of I x 10-3 Torr. Below, a magnetic layer having continuous vertical magnetic anisotropy was formed. The thickness of the magnetic layer was adjusted to approximately 3000A by varying the traveling speed of the substrate. Further, the power input to the electron beam evaporator was kept constant at 4 KW in all cases.

After laminating a magnetic layer of approximately the same thickness on the opposite side of the polyester film in the same manner, using the same evaporator, carbon was evaporated with an electron beam evaporator without gas flow, and a protective layer of approximately the same thickness was applied to both sides. Laminated only to the thickness. after that,
A lubricant (perfluoropolyether manufactured by Montegison Co., Ltd.) was applied to both sides of the magnetic recording medium using a coater, and after air drying, it was punched out into a 3°5-inch floppy disk shape.
It was made into a disk-shaped thin film magnetic recording medium.

Next, polypropylene fibers with a melting point of 170°C (fiber diameter 1
．． 5 denier, fiber length 51 mm) and 75 weight % rayon fiber (fiber diameter 1.5 denier, fiber length 51 mm) to form a web with a basis weight of 35 g/d. This web is then heat treated at a temperature of 1.75° C. using a suction band type hot air heating device. This is liner A
shall be.

In addition, polypropylene fibers with a melting point of 170°C (fiber diameter 1.
After mixing 20% by weight of rayon fiber (fiber diameter 1.5 denier, fiber length 51mm) and 80% by weight of rayon fiber (fiber diameter 1.5 denier, fiber length 51mm) to form a web with a basis weight of 33g/d, the temperature was 185°C and the linear pressure was 2QKg. /m using an embossing calender (convex shape: 0.5 mm x 1.0 mm) to obtain liner B in which the area of the thermo-compressed portion occupies 30% of the web.

In addition, the width is 25 mm and the length is 2 Q mm in advance.

A lifter made of a 125 micron thick polyester film was fixed with adhesive at an angle of 4° to one side of a 3.5 inch floppy disk jacket made of vinyl chloride.

A liner made of A is provided on the liner 5 on the jacket 4 side, and a liner made of B is provided on the liner 2 of the jacket 1 that does not have a lifter.
In Example 1, a liner consisting of the following was provided, and this was combined with the above-mentioned medium.

In addition, a liner made of B was provided on the inner 5 on the jacket 4 side and the liner 2 of the jacket 1 without a lifter, and this was combined with the above medium as Comparative Example 1.

Furthermore, Comparative Example 2 is a case in which liner 5 and liner 2 are each made of a liner made of A, and these are combined with the above-mentioned medium.

When the wear resistance was evaluated, Example 1, which satisfied the conditions of the present invention, had 11 million passes, Comparative Example 1 had 6.5 million passes, and Comparative Example 2 had 8.5 million passes.

Furthermore, similar results were obtained when the materials for liners A and B were changed to polyester fibers or nylon fibers instead of polypropylene fibers.

[Effects of the Invention] According to the present invention, the surface of the magnetic disk is constantly cleaned, preventing dropouts from occurring during recording and reproduction, and the liner does not damage the magnetic disk or prevent smooth rotation. Even during long-term use, troubles due to deterioration of wear resistance do not occur, the reliability and durability of the magnetic disk are improved, and the performance of the thin-film magnetic disk can be fully demonstrated.

[Brief explanation of the drawing]

The figure is a schematic perspective view for explaining the basic structure of a floppy disk in an exploded manner. 1.4 Nijyake Soto, 2.5 Niliner 3: Disc-shaped thin film magnetic recording medium, 6: Lifter

Claims (1)

[Scope of Claims] 1. A floppy disk comprising a disk-shaped magnetic recording medium in which thin-film magnetic recording layers are laminated on both sides of a base film, and a jacket in which liners are disposed in contact with both sides of the medium, in which a lifter of the liner is disposed. At least the lifter contacting part of the liner placed on the side of the jacket that has a lifter is made of a liner made of the following A, and the liner placed on the side of the jacket that does not have a lifter is made of a liner made of at least the following B. floppy disk. A: A nonwoven fabric made of a web made of rayon fibers and thermoplastic fibers with a melting point of 100 to 300°C, in which the thermoplastic fibers are heated and melted under substantially no pressure, thereby bonding the intersections of the rayon fibers. B: A nonwoven fabric having concave portions on the surface of the web made by partially thermocompressing a web made of rayon fibers and thermoplastic fibers with a melting point of 100 to 300° C. at a temperature higher than the softening point of the thermoplastic fibers. 2. Claim 1, wherein the thin film magnetic recording layer is a perpendicular magnetic recording layer made of cobalt and its partial oxide.
The mentioned floppy disk.