JPS6346186B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for forcibly charging a continuous filament transferred from an air sucker, and opening the air sucker using electrical repulsion. More specifically, the present invention relates to a method of forcibly charging a portion of high-speed air ejected simultaneously with a continuous filament from an air sucker after separating it. As a method for forming a nonwoven fabric from continuous filaments, filaments spun from a spinneret are directly stretched and transferred with an air satcher to form a web on a conveyor, or the stretched tows or filaments are taken up with an air satchel. There are methods such as forming a web on a conveyor, and all of these methods require an air sucker to have the function of stretching, transporting, or transporting the web. In order to transport the filaments using such an air sutcher and form a web on the web conveyor, it is necessary to sufficiently open the filaments transferred from the air sutcher.One way to do this is to forcibly charge the filaments. A method is known that uses electrical repulsion. Generally speaking, this method of forcibly charging a filament by applying a corona discharge from an electrode kept at a high voltage is used.In principle, by controlling the voltage, the filament can be charged. However, when it is actually applied to continuous filaments transferred from an air suction car, it is difficult to maintain a constant flow rate and spread of the accompanying high-speed air, and the opening is difficult to achieve. It has been found that the fibers have the disadvantage that the degree of fibers varies. In addition, in recent years, high productivity has been pursued in the production of nonwoven fabrics, and attempts have been made to suction more filaments into one air sucker and transport them at higher speeds, but when it comes to opening filaments, As the amount of high-velocity air increases, forced charging is becoming increasingly difficult. In an attempt to improve these, higher voltage and more electrodes were installed.
Attempts have been made to apply multiple corona discharges, but if the voltage is too high, arc discharges may occur, resulting in poor stability, and this is not desirable from the standpoint of work safety. Further, providing a large number of electrodes has disadvantages such as complicating the threading operation and increasing equipment costs. The present inventors have arrived at the present invention as a result of intensive studies on a filament opening method that eliminates these drawbacks, has excellent opening safety, and can withstand high production. That is, in the present invention, when the continuous filament transferred from the air sucker is forcibly charged and opened by the electric repulsive force, the continuous filament transferred from the air sucker is separated by air using a narrow rectangular or cylindrical slit. It is an object of the present invention to provide a method for opening a continuous filament, which is characterized in that surplus high-speed air is separated at the inlet of the air separation device by running the filament inside the device, and then the filament is forcibly charged. There are two types of air suckers: those with round filament suction ports and those with rectangular slits.
Although either form can be used in the present invention, the shape of the subsequently installed device will be influenced by the shape of the air supporter. That is, if the air sucker is rectangular, the filament running portion of the air separation device must be shaped into a rectangular slit, and if the air sucker is round, the air separation device may have a rectangular slit or a cylindrical slit. In the case of a rectangular slit, these air separation devices basically consist of two plates 1, 1 having a vertical length l and a horizontal length w, as shown in the perspective view of FIG. ′ can be kept at the gap d and opposed to each other, but
In order to ensure that the filament runs, a yarn introduction plate 2 is provided on one of the plates at an angle θ shown in FIG. Therefore, the method of introducing the filament into the slit portion is preferable because the filament can be reliably introduced into the slit portion. The angle .theta. of the yarn introduction plate 2 is preferably 50 to 80 degrees, and various shapes are possible, but any shape is acceptable as long as the filament can be introduced into the slit. The gap d of the rectangular slit into which the filament is introduced in this manner is preferably 3 to 10 mm, and the vertical length l must be at least 30 mm. This is effective in providing resistance to the flow of high-speed air into the slit portion by reducing the length, and if the length is too short, the running of the filament itself becomes unstable. The horizontal length w should be determined appropriately according to the filament's expansion width, and should be set at 10 mm on one side relative to the filament expansion width.
As an air separation device, you only need a margin of about mm.
A cylindrical slit can also be handled in the same way as the rectangular slit mentioned above, but as shown in Figure 2, the inner diameter d of the cylindrical shape is preferably 5 to 10 mm, and the length l is similarly 30 mm or more. is necessary. Further, in order to guide the filament, it is preferable to provide a yarn introduction plate 4 similar to the rectangular slit air separation device connected to the upper part of the cylindrical portion 3. In this way, when traveling through the air separation device, surplus high-speed air other than the high-speed air flowing inside the device is discharged outside the system at the inlet, and at the outlet of the air separation device, there is almost no constant fluctuation. This results in high-speed air. Moreover, since only a certain amount of high-speed air, which has increased due to increased productivity, passes through this air separation device, the effect of the increase has almost no effect on the next process. In this way, by using the air separation device of the present invention, it is possible to reduce the high-speed air flow to 1/5 to 1/3, and even in the subsequent forced charging, the amount of high-speed air is small. Moreover, since there is no fluctuation, it has become possible to easily and stably charge the battery. Next, the present invention will be explained using examples. Example In the production of nonwoven fabric by the spunbond method, in which a large number of filaments are extruded from a spin head, stretched and transferred by an air sucker installed below, and a web is formed on a conveyor, a round air sucker with an inner diameter of 7 mm is used as the air sucker. θ=
d=50mm, l=100mm, w with 70° yarn introduction plate
An air separation device with a rectangular slit adjusted to = 50mm was set up, and immediately after that, a pointed corona discharge electrode and a grounded metal plate were placed on its opposite side, and a 40kV high-voltage power supply was supplied to force the I tried to charge it. Polyethylene terephthalate was extruded using such an apparatus, and the opening state was observed while changing the number of spinnerets, discharge amount, and pressure air amount. In addition, as a comparative example, in parallel, with the same device as above,
Except for the air separation device of the present invention, a corona discharge charging device was connected immediately after the air sucker, and the fiber opening state was compared. The experimental results were as follows.

[Table] In this way, when the air separation device of the present invention is used, even if the production volume increases, production can be performed with sufficiently good single yarn opening, but if it is not used, single yarn opening will be It can be seen that this becomes insufficient and the quality of the web is significantly impaired. As described above, by using the air separation device of the present invention, not only productivity can be improved, but also stable single fiber opening is made possible because only a constant flow of air is allowed to travel.

[Brief explanation of drawings]

FIG. 1 is a perspective view of an air separation device having a rectangular slit portion according to the present invention, and FIG. 2 is a perspective view of a similar cylindrical air separation device.

Claims (1)

[Claims] 1. When the continuous filament transferred from the air sucker is forcibly charged and opened by the electric repulsive force, the continuous filament transferred from the air sucker is run through an air separation device consisting of a narrow rectangular or cylindrical slit. A continuous filament opening method characterized in that surplus high-speed air is separated at the inlet of the air separation device and then forcedly charged.