JP2579347B2 - Nonwoven fabric manufacturing method - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a spunbonded nonwoven fabric in which spun filaments are spread on a screen belt running below a separator and bonded.

Prior art In the method of spreading filaments on a screen belt, a method of spreading and dispersing a group of filaments from a separator, and then spreading the filaments on the screen belt, and providing a reflection dispersion plate below the separator and dropping them on the screen belt How to regulate the position, provide an oscillator under the separator,
Although there are various methods such as a method of shaking the filament group, in any case, the obtained nonwoven fabric generally has a strong strength in the web flow direction, but a weak strength in the width direction, and an unbalanced strength in the vertical and horizontal directions. There was a tendency.

In some cases, the dispersion direction of the filament group is inclined at an angle of 45 ° with respect to the traveling direction of the screen belt. Japanese Patent Publication No. 50-7178 also discloses a method of arranging long fiber bundles on a screen by vibrating a jet guide moving tube in a direction crossing a traveling direction of a screen (hereinafter referred to as "flow direction"). .

When the dispersion direction of the filament group is inclined with respect to the flow direction, the strength increases only in one direction of the dispersion direction and decreases in the direction perpendicular to the direction.

It is difficult to oscillate the jet guide tube at a wide angle and at a high speed for a long operation. If it is vibrated at a low speed, the production speed decreases. Also, even if the guide tube is vibrated at an angle of 45 °, the trajectory where the long fiber bundles accumulate deviates from 45 °, and the guide tube has a sawtooth shape when reciprocating and returning. In addition, since the guide tube has a difference in moving speed between the central portion and the end, a difference occurs in the deposition density in the flow direction and the width direction, and the uniformity is reduced due to uneven thickness. When the guide tube is vibrated at a high speed, the thickness unevenness in the width direction becomes more remarkable.

The present invention solves the above-mentioned problem, there is no anisotropy in strength,
It is another object of the present invention to provide a method for producing a nonwoven fabric having excellent uniformity without thickness unevenness.

Means for Solving the Problems The present invention therefore has one dispersing device in which separators are arranged in a line at an appropriate angle with the flow direction, and a dispersing plate is arranged under the separator so that the filament flow can be restricted with the separator interposed therebetween. Provided, thereby forming a web layer by dispersing the filament group on the screen belt in a direction intersecting the flow direction at an appropriate angle, and then forming the web layer on the screen belt at a different angle from the separator. Is formed by dispersing the filament group at an angle different from that of the filament group through the dispersing device described above to form another web layer and then bonding.

The dispersion direction of the filament group may be at an appropriate angle different from that of the adjacent layer, but in the case of a two-layer structure, the angle is preferably set to about 45 ° with respect to the longitudinal direction, and the dispersion direction of each layer is orthogonal. To be. As a result, the nonwoven fabric has the smallest anisotropy in strength.

Each web layer may be formed in a separate step, but is preferably formed in the same step. In order to form them in the same process, it is preferable to arrange a spraying device including a separator and a dispersing device on a screen belt at different angles to the traveling direction of the belt and in parallel with the flow direction.

To obtain three or more nonwoven fabrics, third, fourth, etc. web layers are similarly formed on the first and second web layers.

For example, as shown in FIG. 2, the dispersing device has a pair of curved dispersing plates arranged so that convex portions face each other, and a pair of straight dispersing plates facing each other gradually narrows downward. And the like arranged as described above.

FIG. 1 shows an example of a manufacturing apparatus used in the present method. On a screen belt 1 driven by circulation, first and second spraying apparatuses 2 and 3 are provided at appropriate intervals in the flow direction. Each of the spraying devices 2 and 3 is composed of a large number of separators 4 arranged at an appropriate angle to the flow direction and a dispersing plate 5 thereunder. Each of the separators 4 of the first spraying device 2 Each of them is arranged at an angle of 45 ° with respect to the flow direction, and each separator 4 of the second spraying device 3 is arranged in a direction orthogonal to the above-mentioned separator. Reference numeral 6 denotes an embossing roll for bonding.

This apparatus is configured as described above, and the filament group is dispersed from each separator 4 of the first spraying apparatus via the dispersion plate 5 onto the screen belt 1 at an angle of 45 ° with respect to the flow direction, and the first layer is formed. Form a web layer. Then a second on it
The filament group is dispersed from each of the separators 4 of the dispersing device via the dispersing plate 5 in a direction orthogonal to the dispersing direction of the web of the first layer. Thereafter, the web 7 composed of both layers is bonded by the embossing roll 6.

In this apparatus, the bonding is performed by an embossing roll, but it can also be performed by another known method, for example, a needle punch, a water jet punch, an ultrasonic welder, or the like.

Although the present apparatus is also provided with first and second spraying devices, three or more spraying devices are provided in order to obtain three or more layers of nonwoven fabric.

The spacing between the spraying devices may be any distance as long as the front and rear filament groups do not interfere with each other, and need not be greatly separated. The larger the spacing, the larger the device.

The strength of the nonwoven fabric obtained by the present invention in the dispersing direction is increased, but the strength is increased in each direction because there are a plurality of dispersing directions. By doing so, the anisotropy in strength is minimized. As the dispersion direction increases, the anisotropy of strength disappears. Also, the dispersing device is fixed and is composed of one dispersing device, and the filament group is scattered at a predetermined angle with respect to the flow direction regardless of the moving speed of the screen belt. A uniform and uniform fiber layer can be formed without causing thickness unevenness.
Moreover, the dispersing device is arranged so that the filament flow is narrowed across the separator, and is re-expanded on the downstream side. A non-woven fabric is obtained.

Example 1 In the nonwoven fabric manufacturing apparatus shown in FIG. 1, each separator 4 of the first spraying apparatus 2 was formed into an inverted V shape, and was disposed at an angle of 45 ° with respect to the traveling direction of the screen belt 1;
Of the dispersing device 3 of (1), the separators 4 also forming an inverted V shape are arranged side by side in a direction orthogonal to the separators. Then, the convex portions face a pair of dispersing plates having an arc shape as shown in FIG. 2 and the lower ends narrowed, and A is 210 mm, B is 70 mm,
Combine so that C is 96mm, screen belt 1
The height D from the screen belt 1 was set to 105 mm, the height E from the screen belt 1 was set to 470 mm, and the rising amount F from the lower end of the separator 4 was set to 5 mm below the separators of the first and second spraying apparatuses.

Next, the basis weight was set to 20 g / m ² , polypropylene was discharged from the nozzles from the first and second spraying devices 2 and 3 at a discharge rate of 200 kg / h, and the spun filament group was air-pressured at 5 kg / m ^2. cm ² , scattered from the separator 4, passed through a dispersion plate, deposited on a running screen belt in the first dispersion device, and formed by the first dispersion device 2 in the second dispersion device 3. The web was further deposited on the resulting web to form a two-layer web. Then, bonding was performed from the embossing roll 6.

Example 2 A nonwoven fabric was manufactured under the same conditions as in Example 1 except that the basis weight target was 30 g / m ² .

Example 3 A nonwoven fabric was produced under the same conditions as in Example 1 except that the basis weight target was 40 g / m ² .

The tensile strength per 5 cm of the nonwoven fabric obtained in each of the above examples is shown in the following table.

Comparative Example 1 In Example 1, the filament group was sprayed on a screen belt under the same conditions as in Example 1 by using one of the first and second spraying devices to obtain a nonwoven fabric.

Comparative Examples 2 and 3 Similar to Examples 2 and 3, the basis weight was set to 30 g and 40 g / m ² , and a nonwoven fabric was manufactured under the same conditions as Comparative Example 1.

 The following table shows the tensile strength per 5 cm of the obtained nonwoven fabric.

As is clear from the table, each example has a vertical / horizontal tensile strength ratio L / W of 1.4 to 1.5, which is almost the same as the comparative example, but the strength in the direction forming an angle of 45 ° with the vertical / horizontal direction is as follows. The imbalance was almost eliminated, and the anisotropy was reduced between the strengths in the longitudinal L and transverse W directions.

Effects of the Invention The present invention is configured as described above and has the following effects.

According to the method of the first aspect, it is possible to obtain a nonwoven fabric having a plurality of layers having different dispersing directions, to obtain a nonwoven fabric having less anisotropy in strength, excellent uniformity without thickness unevenness, and uniform without a break. Can be.

According to the method of the second aspect, the above-mentioned nonwoven fabric can be obtained in one step by arranging the spraying devices on the screen belt at appropriate intervals in the flow direction.

[Brief description of the drawings]

FIG. 1 is a schematic view of a nonwoven fabric manufacturing apparatus according to the present invention, and FIG. 2 is a view showing the size of a dispersion plate. DESCRIPTION OF SYMBOLS 1 ... Screen belt, 2, 3 ... Spraying device 4 ... Separator, 5 ... Dispersion plate 6 ... Emboss roll, 7 ... Web

Claims (2)

(57) [Claims] In a method for producing a nonwoven fabric, in which a spun filament is spread and dispersed from a separator and a web is formed on a screen belt running on the downstream side, a separator is formed at an appropriate angle to a flow direction. In addition to the above, one dispersing device is provided under which a dispersing plate is arranged so that the filament flow is squeezed across the separator, whereby the filament group is arranged on the screen belt in a direction crossing the flow direction at an appropriate angle. Forming a web layer by dispersing, and then dispersing the filament group at a different angle from the filament group via a dispersing device having the above structure from a separator disposed at an angle different from that of the separator. A method for producing a nonwoven fabric, comprising forming a web layer and then bonding. 2. The method for producing a nonwoven fabric according to claim 1, wherein a spraying device comprising a separator and a dispersing device is juxtaposed in the flow direction by changing an angle formed with the flow direction.