JPS6180576A - Unwoven fabric for floppy disk liner - Google Patents

Abstract

PURPOSE:To improve the cuttability and adaptability to environment and to obtain the unwoven fabric for a floppy disk liner without generating any naps and deformation due to a change in the environment by incorporating a specified amt. of a resin for processing a regenerated fiber into unwoven fiber consisting essentially of a regenerated fiber. CONSTITUTION:1-2wt%, based on the weight of a regenerated fiber, resin for processing a regenerated fiber selected from urea-form-aldehyde, ethylene- urea, propylene-urea, uronic acid, triazine, and glyoxal resins is incorporated into unwoven fabric contg. >=60wt% regenerated fiber such as continuous filaments of cuprammonium rayon to manufacture the unwoven fabric for a floppy disk liner. The liner is stuck to the inner side of a jacket. The liner can be cut with good cuttability, any naps are not formed, and the liner has good adaptability to environment ranging widely from high temp. and high humidity to low temp. and low humidity. Besides, an excellent traveling property of the disk can be maintained, the liner is not stuck to the disk, and the disk is never damaged.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention is directed to a floppy disk liner (hereinafter referred to as FDL).
(referred to as ). More specifically, the present invention relates to a nonwoven fabric that is attached to the inside of a case, ie, a jacket, for storing magnetic recording media.

<Prior art> Cases for magnetic recording media (hereinafter referred to as media) are generally called jackets, and are made of a copolymer resin sheet mainly made of vinyl chloride resin with a nonwoven fabric on one side for the purpose of protecting the media. It is pasted and placed inside to form a bag.

The non-woven fabric attached to the inside of the media jacket is
Its main purpose is to act as a wiper for the media and to prevent direct contact between the media and the resin sheet constituting the jacket body, thereby avoiding abrasion or damage to the media.

Conventionally, nonwoven fabrics for FDLs, that is, nonwoven fabrics used as FDLs, have been mainly made of recycled fibers (polyolefin fibers may be mixed therein), but the main reasons for this are low electrical properties and moisture absorption and desorption properties. It is humid. First, the electrostatic characteristics will be explained. When using a floppy disk, the media is 300-360 r, p, m
rotates at a speed of At this time, it is well known that static electricity is generated within the jacket due to rotational friction between the liner and the media, and if this static electricity is not removed, it will significantly affect the electrical characteristics of the floppy disk. It is also well known that recycled fibers have significantly better electrostatic properties than synthetic fibers, and that is why nonwoven fabrics made mainly of recycled fibers are used.

Also, in areas like Japan that are prone to hot and humid environments,
A so-called dew condensation phenomenon may occur due to rapid environmental changes. In order to alleviate such a phenomenon, it is preferable that K be a recycled fiber that also has moisture absorption and desorption properties.

As mentioned above, as the nonwoven fabric for FDL, a nonwoven fabric mainly made of recycled fibers is used. However, even when these nonwoven fabrics are used as FDL, the following problems are becoming noticeable. That is, there are problems during the production of the jacket and problems associated with the expansion of the environment in which the 76T Bee disk is used.

The details will be explained below.

Jacket production is becoming a continuous process and becoming faster due to the rapid increase in demand in recent years. To explain an example of the process, when a PVC sheet having the width necessary to make a jacket is running on a flat surface at a constant speed, a nonwoven fabric cut into a shape necessary and sufficient to make the jacket is placed on the top surface of the sheet at a constant speed. It is supplied and placed at intervals. The PVC sheet is then cut to a regular length, and while moving on a conveyor, it passes between hot embossing rolls together with the nonwoven fabric placed on the top surface and is thermally bonded. After that, the jacket material before bending is completed through punching. Nonwoven fabrics are usually supplied in rolls, which are unwound into sheets and then cut into a certain length with a rotating blade, which are then fed onto the PVC sheet at regular intervals as mentioned above. ing.

As the production speed of jackets increases, disadvantages arise in that the nonwoven fabric sticks to the rotating blade, impeding its placement, and that incomplete cutting causes process troubles. In addition, if the cut surface of the nonwoven fabric is cut loosely, fuzz will occur on the cross section, which will cause a fatal defect in floppy disks. In other words, during use, the fuzz will get caught in the magnetic head of the disk drive, causing recording errors. or reading blemishes.

In order to solve the above-mentioned problems, the need to improve the cutting properties of nonwoven fabrics has increased significantly in recent years.

Next, we will explain the problems associated with the expansion of the usage environment for single floppy disks. In recent years, the applications of micro combinators have continued to expand.

Accordingly, it is used under various environmental conditions. Therefore, if the 70-tip disc, which is an attached equipment to the comviator, is exposed to various environments, the damage will be high. For example, in terms of temperature and humidity, it is used in a wide range from a high temperature and high humidity region (eg, 70° C., 85 cm RH) to a low temperature and low humidity region (eg, θ° C., 301% RH). If a sudden environmental change occurs before or after using a 70-tsupee disk, the jacket of the floppy disk, which is made of conventional non-woven fabric, may become distorted or deformed, a phenomenon known as ``slip''. occurs. When a floppy disk with this "corrosion" is inserted into a disk drive and attempted to be used, smooth rotation of the medium cannot be obtained and the disk cannot be put to practical use. There is an urgent need to improve environmental adaptability to withstand such wide-ranging changes in temperature and humidity and maintain a normal shape.

<Problems to be Solved by the Invention> An object of the present invention is to provide a nonwoven fabric for FDL that has excellent cuttability in the jacket manufacturing process and has excellent environmental adaptability during use.

Means for Solving the Problems> As a result of intensive research, the present inventors have developed the present invention in order to make the most of the advantages of recycled fibers while fundamentally improving the aforementioned problems, namely cuttability and environmental adaptability. Reached.

The object of the present invention is achieved by incorporating a resin for processing recycled fibers in a range of 1% to 12% of the weight of recycled fibers into a nonwoven fabric mainly composed of recycled fibers.

This resin processing allows the resin to enter the micellar spaces of the fibers.
Through thermal crosslinking reactions, they either deposit between fibers or react with fiber molecules to form strong chemical bonds. As a result, appropriate stiffness is imparted to the nonwoven fabric. In addition, the fibers are fixed with appropriate hardness. These effects significantly improve cutting performance.

On the other hand, the resin deposits between the fibers to firmly fix the structure between the fibers, and the shrinkage of the fibers due to the absorption and desorption of moisture due to the inter- and intramolecular hydrogen bonds unique to regenerated cellulose. It can be seen as a result of chemical bonds, etc. This effect also dramatically improves environmental adaptability. That is, the regenerated fiber normally swells when it absorbs moisture, and elongates when exposed to moisture. When placed in a low-humidity environment, it dehumidifies until it reaches a specific equilibrium moisture content. At this time, the fibers shrink due to the action of hydrogen bonds unique to cellulose molecules. Therefore, the nonwoven fabric as a tissue also contracts, and the jacket is deformed due to the contractile force. This is the point that the inventors of the present invention have clarified through their painstaking effort to elucidate the phenomenon of "sagging" of jackets, and the present invention has been achieved based on this knowledge.

The recycled fiber processing resins used in the present invention include urea-formaldehyde, ethylene-urea, fluoropylene-urea, uron, triazone, and glyoxal resins. Particularly preferred here are urea-formaldehyde resins and uron resins.

The resin used in the present invention is not limited to the above-mentioned processing resins, but the point is to perform appropriate processing using a resin that can respond to the phenomena described in detail so far.

The content of the recycled fiber processing resin is determined by the IL of the weight of the recycled fiber.
A range of 12% from s is preferable. If it is less than 1%, the fibers will not be sufficiently modified and the effect of resin processing will not be obtained. Moreover, if it exceeds 12 inches, the fibers become too brittle and the strength decreases, which is not preferable. Particularly preferred range is 4% to 8%
It is.

There are various methods for incorporating resin into the fibrous material layer, such as the shower method, roll boat method, and dipping method.
There is no limitation on the method of providing it.

In order to take advantage of the characteristics of recycled fibers and to fundamentally improve the cuttability and environmental adaptability of the present invention, the nonwoven fabric of the present invention should contain at least 60% by weight of the constituent nonwoven fabric.

Preferably, the top layer is recycled fiber. If the composition ratio is less than 60% by weight, it is not only difficult to obtain the expected effect even when processing with the resin for processing recycled fibers of the present invention, but also the effectiveness of using the recycled fibers described above is reduced, which is not preferable.

<Example> The present invention will be described in detail below based on several examples.

Example 1 A continuous filament (single yarn 2 denier) of steel ammonia rayon was used as the recycled fiber, and a nonwoven fabric made from this fiber was produced according to the nonwoven fabric production method disclosed in Japanese Patent Publication No. 52-6381. The obtained nonwoven fabric was porous, had a sigage-like appearance, and had excellent flexibility. This nonwoven fabric was made from 100% recycled fibers.

Next, using a nonwoven fabric made of polyester fiber continuous filament (single yarn 1.5 denier) obtained by the method for manufacturing a nonwoven fabric made of polyester synthetic fiber disclosed in Japanese Patent Publication No. 1, No. 1, Japanese Patent Publication No. 49-6150, The above-mentioned two nonwoven fabrics were laminated together with a nonwoven fabric and a known quarter jet flow was applied from above, and three types of nonwoven fabrics were produced by changing the amount of recycled fibers to 80vt%, 60wt%, and 50wt%. .

These nonwoven fabrics were treated using resins for blowing fiber processing manufactured by Dainippon Ink Chemical Co., Ltd. as shown in Tables 1 and 2.

For resin processing, the resin is immersed in a resin bath (resin concentration at a bath ratio of 1:10001; a concentration that contains 51 to 14% of recycled fiber K is selected), then picked up in a mangle with 100 g, and dried in a hot air tunnel. After preliminary drying at 80°C for 3 minutes, it was heated at 150°C for 3 minutes.

After resin processing, the characteristic values of the nonwoven fabric were measured to evaluate its improved cuttability and environmental adaptability. Strength and elongation, cuttability, and warp value were evaluated as characteristic values.

Next, methods for measuring each characteristic value will be described.

◎ Strength and elongation: Follow JIS L-1096, 6, and 12 textile testing method and strength and elongation measurement method. A sample of width 56R x length 9 was taken and
, Ltd., Ten5ilon/UTM-4
-100, set the grip length to 5, and pull speed to 10.
Tensile strength and elongation were measured at crn/min when the sample was cut.

Strength is expressed by boiling, and elongation is expressed by .

◎Cutability: Cuttability is expressed by the following four measured values.

That is, bending resistance is a measure of hardness, wrinkle resistance is a measure of stiffness, and cutability and nail resistance are qualitative indicators of ease of cutting.

O Bending resistance: Measured by JIS-L-1096, 6, 1945° cantilever method. The unit of measurement is silk.

O Wrinkle resistance: JIS-L-1096,6,22 Wrinkle resistance; Measured using the wire method.

○ Cutting performance: Paper cutter 20- manufactured by Lion Corporation
Using 8 N, apply 3.0 ky to the handle end of part of the movable cutter.
The ease of cutting is measured when the sample is cut at a speed of 0.5 m/sec under a load of .

The size of the sample is 130 am x 130 m, and the cutting position is KL so that the 65 point of the bamboo of the length of the sample hits the blade, and sample #: l: Cut by accurately hitting the reference frame of the cutter.

Ease of cutting was evaluated by cutting 20 times, ◎ if it was possible to cut 18 times or more without leaving any residue, ○ if it was cut 17 to 15 times, Δ if it was 14 to 10 times, and × if it was 9 times or less. Toshi destination.

○ Stickiness: Stickiness refers to the stickiness of the sample to the blade part when cutting.Evaluation is when cutting is performed 20 times, and the stickiness is 2 or less ◎, 3 or more times and 5 times ○, 6 to 10 times Δ, and 11 or more times ×.

◎ Warpage value: Cut the sample non-woven fabric into 5crn width and 13Lyn length, paste it on a vinyl chloride board used for FD jackets manufactured by Shin-Etsu Polymer Co., Ltd., which is 5crR width and 15 length, and fix it. Fix one end to a plate and heat to 60℃.
'C1 After being left for 1 hour under the environmental condition of 95 degrees of humidity, 6
The plate was left at 0°C and humidity of 25 degrees for 1 hour, and then the stiffness value of the vinyl chloride board was measured. The distance value is expressed as the height at which the free end of the vinyl chloride is separated from the fixing plate.

Table 1 shows the characteristic values when the resin content of the nonwoven fabric was changed. This example shows the characteristic values when recycled m and m100 nonwoven fabrics are used, and one type of resin is used and its content is varied.

Furthermore, as a comparative example, characteristic values without resin processing are shown.

As can be seen from the table, the samples shown in the comparative examples that were not subjected to resin processing had low bending resistance and wrinkle resistance, and had poor cuttability and cuttability as measured by x in both cuttability and stickiness. It also has a high warpage value, indicating poor environmental adaptability.

On the other hand, in the nonwoven fabric containing the resin of the present invention, firstly, at a resin content of 0.5 inches, both cutability and stickiness are Δ
The evaluation shows that the improvement is not very effective. Further, it can be seen that when the resin content is 14%, the tensile strength and elongation are reduced and the material becomes brittle and cannot withstand use.

When the resin content was in the range of 1 to 12 inches, all the characteristic values showed good values, indicating that both cutting properties and environmental adaptability were improved. Therefore, the preferable range of resin content is 1 to 12 yen), cutability,
It can be seen that the more preferable range is from 4 to 8, based on the good evaluation of the stickiness.

Table 2 shows the characteristic values when the type of resin contained in the nonwoven fabric was changed. As can be seen from the table, ethylene urea, propylene urea, urea formaldehyde, uron, triazone, and glyozal are effective. Particularly, those using urea-formaldehyde type or uron type have high wrinkle resistance, good cutability and stickiness, and low warpage value.

Table 3 shows the characteristic values when the amount of recycled fibers in the nonwoven fabric was changed. As can be seen from the table, when the amount of recycled fiber is 60%, the VcO rating for both cutability and stickiness is 50%.
It can be seen that 60g6 or more of recycled fiber is required for the Δ evaluation.

The following is a margin Example 2゜ A nonwoven fabric obtained by applying 1 water kneading to viscose rayon short fibers with a single yarn fineness of 2 denier and a length of 15 was applied to a nonwoven fabric manufactured by Dainippon Ink Chemical Co., Ltd. used in Example 1. Processing is performed using fiber processing resin. The treatment method is Example 1
I followed the method. Table 4 shows the characteristic values of the treated nonwoven fabric.

In addition, as a comparative example, the characteristic values were measured for a product that was not subjected to resin processing and are shown in the table.

As can be seen from the table, those without resin processing have low wrinkle resistance and stiffness, and are rated X for cutability and stickiness. It shows that the sex is not good.

In contrast, the nonwoven fabric containing the resin of the present invention showed good evaluations of ◎ and ○ in terms of wrinkle resistance, high bending resistance, cutability, and stickiness, indicating that the cutting performance was improved. It shows. In addition, the strength value was lower, indicating improved environmental adaptability.

Implementation Project 3゜Visco, which has traditionally been used as a waste woven fabric for FDL.
80% Surelan short fibers and 20% polypropylene short fibers
The composite nonwoven fabric was processed with resin. The resin is Example 1
A urea-formaldehyde system was selected from among those used in . The resin processing method was in accordance with Example 1. Table 5 shows the characteristic values of the treated nonwoven fabric.

In addition, as a comparative example, the characteristic values were measured for a product that was not subjected to resin processing and are shown in the table.

As can be seen from the table, the wrinkle resistance and bending resistance were increased by the resin treatment, and the cutability and stickability were evaluated as ◎ and O, indicating that the mounting properties were improved. The lowered curvature value indicates improved environmental adaptability.

Margins below (Effects of the Invention) By using the nonwoven fabric of the present invention, it is possible to speed up the production of jackets, suppress fuzz generated from cut surfaces, and produce highly reliable jackets. becomes possible.

Moreover, it is possible to provide a jacket that can be adapted to a wide range of usage environments, which is very beneficial.

Claims (3)

[Claims] (1) Add recycled fiber processing resin to a nonwoven fabric mainly composed of recycled fibers at 1% of the weight of the recycled fibers constituting the nonwoven fabric.
A nonwoven fabric for a floppy disk liner, characterized by containing the content in a range of 12% to 12%, and having improved cuttability and environmental adaptability. (2) The nonwoven fabric for a floppy disk liner according to claim 1, wherein the nonwoven fabric mainly consists of recycled fibers at least 60% by weight or more. (3) The recycled fiber processing resin is urea-formaldehyde-based, ethylene-urea-based, propylene-urea-based, uron-based,
The nonwoven fabric for a floppy disk liner according to claim 1, characterized in that the nonwoven fabric is selected from triazone-based and glyoxal-based resins.