JPS59204958A - Opening of filament group - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] The present invention relates to a method for opening a group of filaments.

More specifically, the present invention relates to a method of imparting an extremely high amount of electric charge to a group of filaments to properly open the group of filaments.

Conventionally, various techniques have been proposed as methods for opening filaments, such as applying static electricity to the filaments to spread them, using fluid to spread them, and mechanical Techniques for opening the fibers by force are known. These can be used as desired depending on the purpose of fiber opening, but for example, in the method of depositing a group of filaments on a net conveyor to make a nonwoven fabric, it is possible to use contact charging due to friction or collision or charging due to corona discharge. A technique is generally used in which a uniform nonwoven fabric is created in which each filament is opened by mutual repulsion between the filaments.

However, the problem with the electrostatic opening technology known so far is that the amount of static electricity applied to the filament is still insufficient, making it impossible to obtain a satisfactory opening state, or that the atmosphere etc. The problem was that it was affected by the flexibility of the fibers, and the amount of charge and opening state were unstable. The present inventors have discovered that the method disclosed in Japanese Patent Publication No. 44-21817 or Japanese Patent Publication No. 54-28508, etc., in which the filament group is charged by corona discharge by passing the filament group through a corona discharge electric field, is stable. However, even with this method, the amount of charge was insufficient, and a satisfactory opening condition could not be obtained, especially when the number of filaments was reduced. When increasing the number of filaments or increasing the running speed of the filaments, the opening condition deteriorates markedly, and there are parts where several filaments to medium-sized filaments or more are piled up in bundles without being opened. There was a problem that the uniformity and quality of the obtained nonwoven fabric were extremely poor.

In view of these points, the inventors of the present invention have repeatedly investigated the amount of lead in a technique to give an unprecedentedly high amount of electric charge to the filament group and obtain an extremely good opening state with high productivity when opening the filament group. As a result, the present invention was completed.

That is, the present invention provides a method for opening filaments by applying static electricity to the filaments, in which the filaments are passed through a corona discharge electric field and then collided with a conductive material that is energized to a voltage of 20 kV or higher by a high voltage power source. This is a method for opening a group of filaments, which is characterized in that the filaments are opened using a method of opening filaments.

The present invention is a novel method in which a group of filaments charged by corona discharge collide with a conductive material stably charged with a voltage of 20 kV or more. A high amount of electric charge and an extremely good fiber opening condition, which could not be obtained by other methods or combinations thereof, can be easily obtained with high productivity, and the benefits are extremely large.

In the present invention, the filament group is first passed through a corona discharge electric field. As a corona discharge method for this purpose, any conventionally known method may be adopted, for example,
As disclosed in Japanese Patent Publication No. 21817 and Japanese Patent Publication No. 54-28508, a corona discharge method consisting of a needle-like electrode and a planar or curved electrode is generally preferable, and a corona discharge method using a needle-like electrode and a planar or curved electrode is preferable. Usually, a voltage of 10 to 60 kV is applied, and a group of filaments is passed through the gap between the two electrodes to create a state in which a corona current is generated. In this case, it is possible to form various electric fields depending on the arrangement of the needle electrodes, the shape of the planar electrodes, and the distance and voltage between the two electrodes.
May be taken arbitrarily. As electrodes for corona discharge, in addition to such a combination of a needle electrode and a planar electrode, combinations of a needle electrode and a needle electrode, a planar electrode and a planar electrode, and a rod-like electrode and a rod-like electrode may be adopted. It is also possible to use a cylindrical or truncated conical electrode.

The method of passing the filament group through this corona discharge electric field is preferably a method using the propulsion force of gas flow, and the filament group is easily sent to the next step shown in the present invention,
The filament group is given an amount of charge that is greater than the maximum amount of charge that can be obtained by corona discharge. Here, the maximum amount of charge obtained by corona discharge is ``For example, as disclosed in Japanese Patent Publication No. 44-21817, when a filament is charged by corona discharge, the corona current value is moderated. Even if it is too high, the amount of charge on the filament will decrease due to the reverse corona, or arc discharge will occur. It is the amount of electric charge.

That is, the present invention includes a step in which the charged filaments are passed through a corona discharge electric field and collided with a conductive material that is energized to 20 kV or higher by a high voltage power source, thereby opening and separating the filaments.

The 20 kV here refers to an absolute voltage, which is a high DC voltage, and the sign may be positive or negative, but it is selected to match the sign during corona discharge.

That is, in the case of negative corona, it is taken as negative, and in the case of positive corona, it is taken as positive. This voltage is preferably 20 kV or higher to obtain the young trees of the present invention, and is usually 30 kV or higher, depending on the conditions of corona discharge and the materials of the filament and conductive substance.
~70kV gives favorable results.

This conductive substance has a high voltage applied to it, and if there is a grounded conductor around it, a discharge will occur between them, so keep a distance from these and take precautions to prevent corona discharge from occurring with the ground electrode. will be installed in Therefore, the distance between the corona discharge part and the conductive material may be set arbitrarily within a range where this discharge does not occur, and usually a distance of several meters or more is set.

The conductive substance used in the present invention refers to an inorganic or organic conductive substance. In order to collide and open the filaments, hard materials are suitable from the standpoint of durability and stability, such as iron, SUS, and copper.

Metals such as chromium, nickel, lead, zinc, and other metals and alloys are preferred, but conductive inorganic materials or conductive organic materials may also be used. Further, the surface of this conductive substance may be flat or curved, and the roughness of the surface may be arbitrary, but a smooth surface gives preferable results. This conductive material is connected to a power source that generates high voltage and is always kept at a certain potential.

In the present invention, a group of filaments that have been charged in advance by corona discharge collide with the charged conductive material to open the filaments. In other words, by moving a group of filaments using the propulsive force and inertial force of a gas flow and colliding with a conductive material, the amount of charge previously obtained by corona discharge was dramatically increased, and the bundle of filaments was eliminated. An open state can be obtained. Further, at this time, the filament group exhibits a good opening state as the width as a whole expands due to the diffusion of the gas flow after the collision and the diffusion effect of the filament itself. However, the effect of applying electricity to the conductive material in the present invention is essentially to increase the amount of electric charge on the filament, and as a result, the bundle of filaments is eliminated and the overall width is increased. In a method that is not based on the invention, for example, when a group of filaments charged by corona discharge collides with an unelectrified conductive material, the overall width is wider than when the filaments are not collided, but the amount of charge tends to decrease. It is clear from the fact that the state of the bundle of filaments hardly changes, and that by applying electricity to the conductive material at this time, the overall width further increases and the bundle of filaments disappears.

It is preferable that the collision between the filaments and the conductive material is such that the traveling direction of the filaments is changed, and a contact angle of 5 to 75 degrees provides good results.

The traveling speed of the filament group and the amount and speed of the gas flow that serves as the propulsive force may be arbitrarily selected within the range where the filament group collides with the conductive material. It may also be possible to apply motion such as vibration.

Further, the number of collisions is not limited to one, and it goes without saying that collisions may occur many times.

The filament group as used in the present invention refers to a plurality of filaments, and may be in a bundle, or in a thinly spread bundle in the shape of a tape or lysine. They may be arranged at regular intervals. The filaments include so-called filament-forming materials, synthetic fibers such as holamide, polyester, polyolefin, polyacrylonitrile, recycled fibers such as rayon, and inorganic fibers such as glass fibers. The filament may be a composite fiber made of different components or a mixed fiber, and its diameter may be arbitrarily selected.

Next, the present invention will be explained with reference to the drawings.

FIG. 1 is a schematic diagram showing an example of the method of opening filament group i according to the present invention, in which the filament group 2 ejected from the spinneret 1 is taken up by an air sucker 3, and the ejected filament group is After being charged by passing through a corona discharge electric field region connected to a DC high voltage power source 4 and consisting of a nine-needle electrode 5 and a flat plate electrode 6, it is caused to collide with a flat plate 7 made of a conductive material connected to a DC high voltage power source 4'. , the fibers are opened and deposited on a net conveyor 8 to form a nonwoven web 9.

FIG. 2 shows another embodiment of the present invention, in which a group of filaments drawn or drawn by a high-speed rotating roll 10, 10' is guided to a corona discharge section by an air sucker 3'. A nonwoven web is formed by colliding with a plurality of electrified collision plates 7, 7'.

The present invention may be used not only as a method for manufacturing such a spread sheet-like product, but also for various types of fiber spreading for mixed fibers and other purposes.

Hereinafter, the present invention will be explained in more detail with reference to Examples.

In addition, the amount of charge in the examples was measured using a charge positioning needle (model KQ-431B manufactured by Kasuga Denki).

Example 1 Polyethylene terephthalate was discharged from a spinneret having 86 holes by the method shown in FIG. o
Air soccer placed at position m (pressure 4. OK
9/all G, flow rate a 5 Nrr? /)lr)
A filament group having a single yarn of 1.5 denier was obtained. The yarn speed of the filament group at this time was calculated to be 4800 m/min. A corona discharge unit with 10 needle electrodes and SUS flat plate electrodes set at a distance of 17 mm below the air sucker is installed, and further below the unit 45 at 80 tomo position
A copper collision plate was installed at a degree angle, and the corona discharge unit and the collision plate were each connected to separate high-voltage DC power sources.

The voltage applied to the corona discharge and the collision plate was set to -30k, respectively.
V, −25 kV, and the filaments were processed and deposited on a net conveyor.

The resulting nonwoven web had no bundles of filaments at all and was opened so that each filament had a single filament shape.

Still, the amount of charge on the filament at this time is 28μC15
' Met.

Comparative Example 1 The operation of Example 1 was carried out by grounding only the collision plate without applying electricity, but in this case, the amount of charge on the filament was 12
With μC/P, bundles of filaments were present throughout the web, and the quality of the web was inferior to that obtained in Example 1. When the filament structure was observed under a microscope, it was found that it was a collection of 6 to 20 filaments, and some of the filaments were twisted together.

Example 2 According to the method shown in Fig. 2, polyethylene terephthalate was discharged through a spindle with 200 holes, taken up by a pair of high-speed rolls, and then air sucked (pressure: 40 KP/cy+!).
A filament group having a single yarn of 2.0 denier was obtained. The yarn speed of the fiment group at this time is converted to 4900y4/min.

A corona discharge unit of the same type as in Example 1 was installed at a position approximately 5 mm below this air sucker, and a first collision plate made of copper was installed at an angle of 45 degrees at a position 80 mw below the unit, and a A second collision plate made of copper was installed vertically to create a spacing of 5.5 mm, and the two collision plates were connected to one DC high voltage power source separate from the one for corona discharge.

The filament group was processed and deposited on a net conveyor by applying a voltage of -35 kV to the corona discharge and -40 kV to the two collision plates.

The amount of charge on the filament obtained at this time is 28μC/P
The nonwoven web was extremely uniform, and no filament bundles were observed with the naked eye.

Examples 3-4. Comparative Examples 2 to 3 The operation of Example 2 was repeated while the corona discharge section was kept energized at -35 kV and the collision plate was struck while changing the energization state.

The results are shown in Table 1.

Table 1 - Example 5 Polyzolopyrene (Chisso [5
Sose) is used as the material, and a SUS flat plate is used as the collision plate material.
I made a web of 0 filaments.

By setting the corona discharge to -35 kV and the two collision plates to -45 kV, the amount of electric charge on the filament is 25 μC/1.
The amount of charge when reaching il- and grounding the collision plate is 9μc7
y- was greatly improved. Moreover, the difference between the two nonwoven webs was clear, and the nonwoven web to which the collision plate was energized was uniform, had no filament bundles, and had a wide width.

[Brief explanation of drawings]

FIGS. 1 and 2 are schematic diagrams showing an example of an embodiment of a method for opening a group of filaments according to the present invention. l... Spinneret, 2... Filament group,
3, 3' -...Air soccer, 4.4'
...DC high voltage power supply, 5... Needle electrode, 6
...Target electrode, '1.7'...Collision plate, 8...Net conveyor, 9...Nonwoven web, 10,10'...・Rotating roll. Patent applicant: Asahi Kasei Industries, Ltd.

Claims (1)

[Claims] In the method of opening filaments by applying static electricity to them, after passing the filaments through a corona discharge electric field,
A method for opening a group of filaments, characterized by colliding with a conductive material charged with a voltage of 20 kV or higher by a high voltage power source to open the filaments.