JPH01199371A - Nonwoven fabric for floppy disk liner - Google Patents

Abstract

PURPOSE:To reduce temporary errors and to eliminate a scratch character by blending a rayon fiber, a polyester composite fiber and the polyester binder fiber of a specific melting point in a specific ratio, respectively and simultaneously, specifying the thickness of a nonwoven fabric after heating-bonded and embossing-bonded. CONSTITUTION:The rayon fiber is 25-40wt.%, the polyester composite fiber is 25-40wt.%, and the polyester binder fiber whose melting point is 110-140 deg.C is 50-20wt.%. Simultaneously, the thickness of the nonwoven fabric after heating-bonded and embossing-bonded is 0.15-0.35mm under 6.0g/cm<2> load. By using the crimpy polyester composite fiber and polyester binder fiber, the sweeping work of a floppy disk can be increased. By mixing the rayon fiber in a polyester nonwoven fabric, a form dimensional stability at the time of a high temperature and a high humidity cannot be damaged, and simultaneously, the copy error rate of the disk can be reduced. By maintaining the thickness of the nonwoven fabric is 0.15-0.35mm, a scratch on a disk surface cannot be generated.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a nonwoven fabric for floppy disk liners.

<Prior Art> With the spread of office automation equipment, floppy disks, which serve as the storage portion of computers and word processors, have come into wide use. Traditionally, floppy disks were used in favorable environments such as computer rooms where temperature and humidity were controlled at a constant level, but recently floppy disks have been used in high-temperature environments such as stores, homes, general offices, steel factories, automobile assembly plants, textile dyeing factories, etc. They are increasingly being used under a wide range of environmental conditions, such as humid environments, and in places with poor cleanliness.

In order to obtain a highly reliable floppy disk even under such harsh conditions, the quality of the disk-shaped disk that is the magnetic recording medium must be maintained, as well as the fact that it comes into moderate contact with the disk when it rotates, and foreign matter on the surface. It is extremely important to improve the performance of the liner to remove the oxidants.The present invention relates to improving the performance of the liner.

By the way, examples of foreign substances that adhere to the disk surface include sand, dirt, dust, and fibrous debris that enter from the outside through the openings. On the other hand, dust and fiber fuzz generated from the jacket or liner itself also have a significant impact on the reliability of floppy disks.

Liners are conventionally made by spraying water or air onto a rayon nonwoven fabric (Japanese Utility Model Application No. 56-103979) whose fibers are fixed with a resinous adhesive or a blend of rayon fibers and thermoplastic polypropylene fibers to entangle the fibers with each other. A mixed nonwoven fabric (Japanese Patent Publication No. 61-36:113) has been proposed in which the fibers are bonded together by heat treatment after heating.

However, although such nonwoven fabrics mainly made of rayon fibers have relatively good cleaning properties, they often generate resin powder and fuzz that separate from the nonwoven fabrics, and their shape changes with changes in temperature and humidity, resulting in poor heat and humidity resistance and dimensional stability. .

In contrast, normal polyester fiber has a melting point of about 150°C.
It has also been proposed to produce liners by heat-treating and embossing non-woven fabrics consisting of polyester fibers of less than (Japanese Unexamined Patent Publication No. 58-77075) However, the nonwoven fabric liner made of 100% polyester fiber obtained by this method has the fatal drawback of easily causing copy errors that must be avoided with floppy disks. .

On the other hand, nonwoven fabrics made of composite fibers made of polyester, polypropylene, polyamide, etc., rayon fibers, adhesive resin (or low melting point fibrous binder), etc. have also been proposed (Japanese Patent Application Laid-open No. 145581/1981). This liner also has the problem of scratching the disk surface during use.

<Object of the Invention> In view of the above circumstances, the present invention was achieved as a result of conducting studies to develop a nonwoven fabric for floppy disk liners that has fewer temporary errors and is free from scratches.

<Structure of the Invention> In the plain fabric for a floppy disk outer packaging container liner (lining material) consisting of rayon fibers and polyester fibers, rayon fibers are 25 to 40% by weight and polyester composite fibers are 25 to 40% by weight.

Polyester binder fibers with a melting point of 110 to 140°C are 50 to 20% by weight, and the thickness of the nonwoven fabric after thermal bonding and emboss bonding is 0.15 to 0.35 am under a load of 6.0 g/- ``A nonwoven fabric for floppy disk liner,'' characterized by:

The nonwoven fabric of the present invention contains 25 to 40% by weight of rayon fibers, and there are no particular restrictions on the fineness or fiber length of the rayon fibers, and any form of rayon *ei for dry/wet nonwoven fabrics can be used.

The blending ratio of rayon fibers must be within the above range. If it is less than 25% by weight, the surface smoothness of the entire nonwoven fabric will be poor, causing problems in dust wiping performance, or causing errors in magnetic storage devices due to static electricity generation. If it exceeds 40% by weight, the dimensional stability under high temperature and high humidity conditions will decrease and the generation of fiber waste will increase.

The components of composite fibers are mainly a combination of polyester/polyester, but some polynisdels are made of polyamide,
An example of a polyester/polyamide system, which may be polyolefin, is a composite fiber made by combining 5-sodium sulfoisophthalic acid 5 mol% (acid component base) copolymerized polyethylene terephthalate and nylon 6 homopolymer. be able to.

There are no particular restrictions on the fineness of the single filament of the composite fiber, but it does depend on the passability of the carding machine and the surface smoothness of the resulting liner.

A range of 0.5 to 4 denier is preferable in terms of texture and the like.

The degree of revealed crimp after heat treatment of the composite fiber is preferably 10 to 50%, more preferably 20 to 40%. If the degree of crimp is less than 10%, the resulting nonwoven fabric will have a weak compression recovery power and will not have a sufficient amount of permanent residence, resulting in insufficient disc protection and dust wiping effect.If the degree of crimp exceeds 50%, the nonwoven fabric will not have permanent residence. Since the torque becomes excessive, the torque when rotating the disk becomes large.

The melting point of polyester binder fiber is 110-140
It is ℃. It may be a polyester homopolymer,
Alternatively, it may be a sheath-core composite fiber in which the core is a high melting point polyester and the sheath is the above-mentioned low melting point polymer.

The nonwoven fabric of the present invention is shaped by thermo-rendering and embossing after being formed by a dry/wet card method or air flow lamination method. However, if the melting point of the binder fiber is less than 110°C, The melting point is 14, which impairs the quality of the liner due to deformation of the nonwoven fabric structure.
When the temperature exceeds 0℃, the industrially used calendar/
The temperature approaches the upper limit of the embossing machine's usable temperature, reducing productivity. The melting point of the binder fiber is determined by a conventional measuring method using a differential calorimeter (DTA) or a differential calorimeter (DSC).

As other additives, a small amount of an antistatic agent, a watering agent, a fiber surface smoothing agent, etc. may be added.

The thickness of the nonwoven fabric of the present invention is 0.1 under a load of 6.0 g/aJ.
5 to 0.35+m. Less than 0.15B or 0.3
When the number of cities exceeds 5, the frequency of temporary errors on floppy disks increases. The detailed reason is unknown, but if the nonwoven fabric is too thin, the ability to wipe away dirt will be reduced, and if the nonwoven fabric is too thick, it will apply more pressure than necessary, making it difficult to achieve smooth rotation, accelerating wear on the disk surface, and It is assumed that the magnetic material falls off and increases temporary errors.

The present invention has the following effects.

1) By using crimpable polyester composite fibers and polyester binder fibers, the electrical properties and flexibility of the nonwoven fabric were increased, and the wiping action of floppy disks was enhanced.

2) By mixing 25 to 40% by weight of rayon fiber into the polyester nonwoven fabric, the dimensional stability at high temperatures and high humidity is not impaired, and the copy error rate of the disc is reduced.

3) Substantially free of adhesive resin and 6.0 g/af
By maintaining the thickness of the nonwoven fabric under a load of 0.15 to 0.35 W, a good disk surface wiping action is maintained and no scratches are generated on the disk surface.

<Examples> The present invention will be specifically explained below using examples. Note that the evaluation of temporary errors was performed according to the following method.

Temporary error measurement method: All initialized signals are retried using a 5174-inch 96TPI floppy disk device.
y) Reading was repeated up to 500 times from 0 times, the number of occurrences of CRC errors in sector units was counted, and measurements were made for 10 samples, and the total evaluation was made.

The measurements were conducted in a semi-clean environment (23°C.

55%RH).

Examples 1-5. Comparative Examples 1 to 8 Copolymerized polyethylene terephthalate containing 3.0 mol% of 5-sodium sulfoinphthalate (melting point 252°C
) and polybutylene terephthalate homopolymer (melting point 2
25°C), make a 1/1 type side pie using the usual method.
A side-type composite fiber was created. The obtained drawn yarn of 1.5 denier was cut into fiber lengths of 51-1 and was used in the following experiment (fiber A).

On the other hand, a 1/1 type sheath-core polyester binder fiber (single filament fineness 2 denier) was produced using a conventional method, with a core layer made of polyethylene terephthalate homopolymer and a sheath layer made of copolymerized polyethylene terephthalate having a melting point of 135°C. The fibers were cut to a fiber length of 51 oun and subjected to the following test. (Thin mB).

Fiber MA, Fiber B and rayon short *! (single yarn fineness 1.5 denier, fiber length 510) were mixed at each weight ratio shown in Table 1, passed through an opener, and then carded at 32t/rtf.
The front and back nonwoven fabrics were created.

Next, this nonwoven fabric was treated with an antistatic agent (rJ AA428).

The sample was immersed in an immersion bath containing Ichisha Yushi Kogyo ■) and dried in a hot air oven at 150°C for 1 minute. The amount of antistatic agent adhered to each sample was approximately 0.5% by weight (based on nonwoven fabric).

This nonwoven fabric was passed through a calendar consisting of metal rolls/metal rolls heated to 110°C at a linear pressure of 10 to 40 kf/■ and a speed of 5 m/ltn, and then the parallel line spacing was 2,
Ow, mountain shape is 0.9 ram C) xl, 5onn
(Length) Xo, 4 am (height) parallel arrangement embossing rolls were used to shape the rolls at a roll temperature of 98° C. and a linear pressure of 50 kg/am to create nonwoven fabrics of different thicknesses.

This nonwoven fabric was attached to a carbon black-containing vinyl chloride sheet with a thickness of 0.25 mm, and after punching out designated window sections, the fabric was bent and fused to create 10 magnetic disk jackets. The temporary error of each sample was measured. The evaluation results are shown in Table 1.

Table 1

Claims (1)

[Claims] (1) In a nonwoven fabric for a floppy disk outer packaging container liner (lining material) consisting of rayon fiber and polyester fiber, the rayon fiber is 25 to 40% by weight, the polyester composite fiber is 25 to 40% by weight, and the melting point is 110 to 1.
The polyester binder fiber at 40°C is 50 to 20% by weight, and the thickness of the nonwoven fabric after thermal bonding and emboss bonding is 6.0 g/cm^2 under a load of 0.15 to 20% by weight.
A nonwoven fabric for floppy disk liners characterized by a thickness of 0.35 mm.