JPH10251957A - Embossing roller for producing floppy disk liner nonwoven fabric - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an embossed roller used for producing nonwoven fabrics which hold softness not injuring the surfaces of floppy disks on their cleaning treatments, are little in the falling of surface fuzzes and fibers causing the generation of record-saving or reading errors of the floppy disks, are good in liner punchability in a process for producing the floppy disks, and are useful for floppy disk jacket liners. SOLUTION: This embossed roller for producing a floppy disk liner nonwoven fabric has embossing projections 1 in an embossing area of 20-50% per unit area on the surface of an embossing roller used on the production of a thermal bonded type nonwoven fabric for floppy disk jacket liners, and further has shelf portions 2 at a lower level than that of the embossing projections 1 on the peripheries or neighborhoods of the embossed projections 1 in a range that the total area of the shelf areas and the embossing projection areas does not exceed 75% per unit area.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermal bond type nonwoven fabric used as a jacket liner for a floppy disk, which is a general-purpose external recording medium, and more particularly to an embossing roller used for manufacturing a nonwoven fabric containing cellulosic fibers.

[0002]

2. Description of the Related Art A floppy disk jacket is generally formed of a flexible or hard resin sheet made of a polymer resin such as a vinyl chloride resin or an ABS resin.
A liner made of a fiber sheet is bonded to the inner surface of the jacket for storing the floppy disk. This liner functions to block direct contact between the floppy disk and the resin sheet forming the jacket and to clean the surface of the floppy disk. Various types of fiber sheets have been proposed as liners.

For example, Japanese Patent Application Laid-Open No. 58-7705 discloses a liner made of nonwoven fabric made of polyester fiber, and Japanese Utility Model Application Laid-Open No. 57-71280 discloses a liner made of nonwoven fabric made of recycled fiber. These are obtained by a method such as fusing fibers together to stabilize the form of the nonwoven fabric, or bonding and fixing the fibers with an adhesive. However, in the case of a non-woven fabric in which the fibers are bonded and fixed with an adhesive, the adhesive may transfer to a disk depending on the use environment, causing a recording storage or reading error. The so-called thermal bond type non-woven liner that has been worn is the mainstream.

The performance required of the liner is not only that the surface of the disk is not damaged during cleaning of the surface of the floppy disk, but also that the liner must be easy to handle during manufacture of the floppy disk. That is, in the non-woven fabric for the liner, surface fluff and fibers are less likely to fall off, and when the liner is punched out in a floppy disk manufacturing process, it is a major factor.

As the nonwoven fabric material, cellulose fibers are preferably used because they do not damage the disk surface during cleaning, do not easily adhere to the disk, and have good scraping properties of dust attached to the disk. Has a structure in which cellulosic fibers are arranged on the side that contacts the disk. In the production of a thermal bond type nonwoven fabric, a method of heat shaping with an emboss roller is most generally used. However, when a cellulose-based fiber is contained, a heat-adhesive binder fiber must be used.

[0006] In particular, in heat shaping with an embossing roller during the production of a nonwoven fabric containing cellulosic fibers, the ratio of the embossing shaping area by the embossing roller has a great effect in addition to the binder fiber, temperature and pressure. In order to sufficiently bond the cellulosic fiber and the binder fiber, it is sufficient to bond them in a large area.However, the embossed shape and the bonded portion lose the flexibility of the fiber, so the embossed shaped portion is Many non-woven fabrics lack softness and damage the disk surface.On the other hand, non-woven fabrics with few embossed parts are soft but do not have sufficient adhesive strength, have more surface fuzz, and fibers are more likely to fall off. The punching property at the time of liner punching in the floppy disk manufacturing process becomes poor.

[0007]

DISCLOSURE OF THE INVENTION The present invention has been achieved as a result of a study on the shape of the embossing-shaped projections of the embossing roller used in the production of a thermal bond type nonwoven fabric by heat shaping with an embossing roller. The object of the present invention is to keep the softness of the non-woven fabric without damaging the disk surface during cleaning of the floppy disk, and to reduce the occurrence of surface fuzz and fibers that cause errors in storing or reading a record on the floppy disk, Another object of the present invention is to provide an embossing roller for producing a nonwoven fabric for a jacket liner of a floppy disk, which has good punching properties when punching a liner in a floppy disk manufacturing process.

[0008]

SUMMARY OF THE INVENTION The present invention relates to an embossing roller for use in producing a thermal bond type nonwoven fabric for a jacket liner in a floppy disk, wherein the embossing area per unit area is 20 to 50 on the roller surface. % Of the embossed convex portion, and a shelf having a step lower than the embossed convex portion around or near the embossed convex portion, in a range where the total area of the shelf area and the embossed area does not exceed 75% per unit area. The present invention provides an embossing roller for producing a floppy disk liner nonwoven fabric.

[0009]

FIG. 1 is a partially enlarged view of a roller surface of an example of an embossing roller provided with a ledge on an embossed projection according to the present invention, and FIG. 2 is a cross-sectional view taken along line AA 'of FIG. FIG. 1 and 2, reference numeral 1 denotes an embossed projection, 2 denotes a bottom, and 3 denotes a shelf.

In general, the embossing roller wears the embossing projections due to its use, so that the embossing projections usually have a certain height. Depending on the embossing pattern, there is also a restriction in designing and working. Usually, the height of the embossed protrusion is about 0.5 mm. If the height of the embossed convex portion is too low, there is also a problem of the life of the embossed roller that the interval before re-engraving the worn embossed convex portion is shortened, but the softness of the obtained nonwoven fabric is impaired, If it is too high, the embossed protrusions are likely to be chipped or the bottoms are likely to be clogged with impurities, resulting in troubles in nonwoven fabric production.

Further, the embossing roller enables the obtained non-woven fabric to maintain the softness of the floppy disk and protect the floppy disk, and to reduce the loss of the fibers from the non-woven fabric, thereby enabling liner punching in the floppy disk manufacturing process. In order to obtain a nonwoven fabric in which fibers are partially adhered to each other, the embossed protrusions are engraved on the roller surface so that the embossed area, which is the upper area of the embossed protrusions, is 20 to 50% per unit area. You.

In a thermal bond type nonwoven fabric formed by heat shaping with an embossing roller, the fibers are adhered to each other at the embossed portion to hold and fix the shape of the nonwoven fabric. Although the softness increases, the inter-fiber adhesion is insufficient, and the fluff and the fibers of the nonwoven fabric are liable to fall off.In order to obtain a sufficient adhesive force, a stronger adhesion state is required by the embossed portion, and the hardened portion caused by the embossed portion is required. Scratches the disc surface. If the embossed area exceeds 50%, the required softness cannot be obtained, and if the softness is to be obtained, the inter-fiber adhesive strength is insufficient.

In the embossing roller of the present invention, it is essential to provide a ledge having a step lower than the embossed protrusion around or near the embossed protrusion. When the nonwoven fabric is heat-formed by an embossing roller provided with a ledge having a step lower than the embossed protrusion around or near the embossed protrusion, the heat-formed part by the shelf is compared with the embossed part by the embossed protrusion. Although weak, the fibers are bonded to each other much more strongly than the non-embossed portions, and the formation of a step portion that remains soft improves the wiping properties and suppresses the surface fluff of the nonwoven fabric and the falling off of the fibers.

The shelf is provided so that the total area of the shelf area and the emboss area exceeds the emboss area and does not exceed 75% per unit area. If the total area of the shelf area and the embossed area exceeds 75% per unit area, the shelf area becomes relatively large, so that the shelf acts like an embossed convex part, and the strongly adhered portion Becomes large, and the nonwoven fabric becomes hard as a whole. Also, depending on the pressure and temperature at the time of heat shaping, the step between the embossed protrusion and the shelf (indicated by L in FIG. 2) is 0.
The height is preferably in the range of 1 to 0.2 mm.

The nonwoven fabric for liners of floppy disks generally used has a basis weight of 35 to 45 g / m ^2.
The thickness is 0.20 to 0.27 mm, and the diameter of the constituent fibers is about 0.015 mm. In the case of a polyester fiber having a fiber diameter of about 0.015 mm and a basis weight of 35 g / m ² and a non-woven fabric having a thickness of 0.20 mm, the specific gravity of the polyester fiber is about 1.3 g / cm ^3. Assuming that the fibers are evenly arranged, an average of about six fibers are overlapped, and the total fiber diameter is about 0.09 mm.

Accordingly, if the step L between the embossed convex portion and the shelf is 0.1 mm or more, the nonwoven fabric is heat-formed without giving strong adhesion to the fiber at the shelf, and the step L is 0.2 mm.
If it exceeds mm, the effect of the shelf is not exhibited, and the meaning of providing the shelf is lost.

The constituent fibers of the non-woven fabric produced by using the embossing roller of the present invention are preferably acrylic fibers and cellulosic fibers, but other polyester fibers and the like conventionally used in non-woven fabrics for liners of floppy disks. May be used, and there is no particular limitation.

The embossing roller of the present invention is preferably used particularly for the production of a thermal bond type nonwoven fabric made of acrylic fiber and cellulosic fiber. In the production of such a nonwoven fabric, the inner layer is made of an acrylic fiber web or acrylic fiber. By forming a mixed web with the fibers of the above, and forming a multilayered web having both surface layers as a cellulosic fiber web or a mixed web of the cellulosic fibers and other fibers by heat shaping with an emboss roller, the jacket liner of the floppy disk is formed. A suitable nonwoven fabric can be obtained.

The nonwoven fabric of the thermal bond type manufactured by using the embossing roller of the present invention retains softness without damaging the disk surface during cleaning of the floppy disk, and has no ledge on the embossed convex portion. Compared with the floppy disk, there is significantly less dust generation due to the drop off of the surface fuzz and fibers which causes the storage or reading error of the record of the floppy disk, and the punching property at the time of punching the liner in the floppy disk manufacturing process is good, Reduced dust improves liner yield.

[0020]

The present invention will be described below in more detail with reference to examples. In addition, the performance evaluation of the nonwoven fabric as a jacket liner of a floppy disk was based on the following method.

<Punching property> The number of fluffs having a length of 2 mm or more generated at the cut portion when the sample nonwoven fabric was punched in a liner form was counted, and the punching property was evaluated based on the number of fluffs. ◎: 3 or less fluffs ○: 4 to 8 fluffs △: 9 to 14 fluffs X: 15 to more fluffs

<Surface Fuzz> A nonwoven fabric sample was stuck on a seal-like sheet, cut into an appropriate size, and the surface of the nonwoven fabric was rubbed with a Gakushin type dyeing friction fastness tester under a load of 500 g / 2.5 cm and 100 reciprocations. The state of the fluff generated on the surface was observed. ◎: extremely short ○: short △: considerably long

<Lint> Ten pieces of the sample nonwoven fabric punched in a liner form were prepared, and 15 cm × 15 cm × 15 c
m was put into a wire mesh box and rotated 120 times per minute, the dropped fiber waste was collected on a black filter, and the amount was visually determined. ◎: extremely small ○: small △: large ×: considerably large

<Dust Producing Property> The sample nonwoven fabric was punched into a liner form and thermocompression-bonded to a 3.5-inch floppy disk shell. After inserting the floppy disk, the upper shell and the lower shell were welded. The number of dust particles having a size of 1 μm or more generated in the head window portion of the disk by the ultrasonic vibration at this time was counted with a microscope.

<Yield Test> Floppy disks obtained by accommodating disks in shells obtained by punching a sample nonwoven fabric into a liner shape and joining the inner surfaces thereof were prepared in a number of 1000 each. Using a drop-in-out counter manufactured by Tokyo Engineering Co., Ltd. as a measuring instrument, the reproduction output was measured three times repeatedly, and a reproduction output of 70% or more was regarded as a pass, and the number of passed sheets (n / 1000) was obtained.

<Vibration Test> 100 floppy disks each having passed the yield test were prepared, packed in a paper box for 50 sheets, and dropped on a rubber mat 30 times from a height of 5 cm. Thereafter, a yield test is performed to measure the reproduction output, and a reproduction output of 70% or more is regarded as a pass.
/ 100).

<Durability test> Ten floppy disks each having passed the yield test were prepared, and 10 million
After the ASS rotation, a yield test was performed, and the reproduced output was measured. When the reproduced output was 70% or more, the number of passed sheets (n / 10) was determined.

(Examples 1 to 3) Fineness 1.5d, fiber length 5
1mm rayon fiber, fineness 1.5d, fiber length 51mm
5 cards were connected to each other using the acrylic fiber, and a multilayer parallel web having a basis weight of 40 g / m ² in which the surface layer was composed of rayon fiber and the intermediate layer was composed of acrylic fiber was produced. This multilayer parallel web is attached to the embossed protrusions as shown in Table 1.
Surface area 2 having an embossed pattern shown in FIGS. 1, 3 and 4 provided with a shelf area ratio and a shelf having a step as shown in FIG.
A non-woven fabric of a thermal bond type was produced by press-fitting with a 40 ° C. embossing roller and heat-forming. Fcol 214 (a paraffin-based antistatic agent manufactured by Matsumoto Yushi Co., Ltd.) was applied to the obtained nonwoven fabric by spray coating so that 0.5% by weight of the nonwoven fabric was contacted with the jacket. This nonwoven fabric was evaluated for its performance as a floppy disk jacket liner, and the results are shown in Table 1.

(Comparative Examples 1 to 3) Surface temperature of the multilayer parallel web produced in the same manner as in Example 1 having the embossed pattern shown in FIGS. 5, 6 and 7 without a ledge on the embossed projections It was press-bonded with a 240 ° C. embossing roller and heat-shaped to produce a thermal bond type nonwoven fabric. Fcol 214 (a paraffin-based antistatic agent manufactured by Matsumoto Yushi Co., Ltd.) was applied to the obtained nonwoven fabric by spray coating so that 0.5% by weight of the nonwoven fabric was contacted with the jacket. The nonwoven fabric was evaluated for its performance as a floppy disk jacket liner, and the results are shown in Table 1.
It was shown to.

Comparative Example 4 A multilayer parallel web produced in the same manner as in Example 1 was embossed as shown in FIG. 1 in which shelves having different shelf area ratios were provided on the embossed protrusions as shown in Table 1. It was press-bonded with an embossing roller having a surface temperature of 240 ° C. having a pattern and heat-formed to produce a thermal bond type nonwoven fabric. F-col 2 on the obtained non-woven fabric
14 (a paraffin-based antistatic agent manufactured by Matsumoto Yushi Co., Ltd.) was spray-coated on the side that contacts the jacket with 0.5
% By weight. This nonwoven fabric was evaluated for its performance as a floppy disk jacket liner.
The results are shown in Table 1.

(Comparative Examples 5 to 6) A multilayer parallel web produced in the same manner as in Example 1 was embossed as shown in FIG. It was press-bonded with an embossing roller having a surface temperature of 240 ° C. having a pattern and heat-formed to produce a thermal bond type nonwoven fabric. F-col 2 on the obtained non-woven fabric
14 (a paraffin-based antistatic agent manufactured by Matsumoto Yushi Co., Ltd.) was spray-coated on the side that contacts the jacket with 0.5
% By weight. This nonwoven fabric was evaluated for its performance as a floppy disk jacket liner.
The results are shown in Table 1.

[0032]

[Table 1]

[0033]

According to the embossing roller of the present invention, the surface of the floppy disk can be kept soft without damaging the surface of the floppy disk during cleaning, and can cause an error when storing or reading a record on the floppy disk. It is possible to obtain a thermal bond type non-woven fabric which has a small amount of fluff and detachment of fibers and has excellent handleability in manufacturing a floppy disk, and also has a good punching property.The embossing roller of the present invention is excellent as a jacket liner for a floppy disk. It is suitably used when producing a nonwoven fabric having excellent performance.

[Brief description of the drawings]

FIG. 1 is a partially enlarged view of a roller surface of an example of an embossing roller provided with a shelf portion on an embossed projection according to the present invention.

FIG. 2 is a sectional view taken along line A-A 'of FIG.

FIG. 3 is a partially enlarged view of a roller surface of another example of an embossing roller provided with a shelf portion on an embossing projection according to the present invention.

FIG. 4 is a partially enlarged view of a roller surface of another example of an embossing roller provided with a shelf portion on an embossing projection according to the present invention.

FIG. 5 is a partially enlarged view of a roller surface of an example of a conventional embossing roller.

FIG. 6 is a partially enlarged view of a roller surface of another example of a conventional embossing roller.

FIG. 7 is a partially enlarged view of a roller surface of another example of a conventional embossing roller.

[Explanation of symbols]

 1 Embossed protrusion 2 Bottom 3 Shelf

Claims (2)

[Claims] 1. An embossing roller for use in manufacturing a thermal bond type nonwoven fabric for a jacket liner in a floppy disk, wherein the roller surface has embossed projections having an embossed area per unit area of 20 to 50%. A shelf having a step lower than that of the embossed projection is provided around or near the embossed projection so that the total area of the shelf area and the embossed area does not exceed 75% per unit area. Embossing roller for manufacturing non-woven floppy disk liners. 2. The step between the embossed convex portion and the shelf portion is 0.1 to 0.1.
The embossing roller for producing a floppy disk liner nonwoven fabric according to claim 1, which is 0.2 mm.