JPS60173155A - Production of nonwoven fabric - 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 producing a nonwoven fabric using a thermoplastic synthetic resin.

As with the production of ordinary synthetic fibers, the common method for producing nonwoven fabrics is to first eject molten signal resin from a spinneret to create a large number of thin filaments, and then use these to create a web. Large scale equipment with expensive spinnerets is required.

In addition, as a method that does not use a spinneret, static electricity is applied between the wire plate and the collector, and the molten synthetic resin is statically charged]
There are methods of spinning a synthetic resin film and using it to manufacture non-woven fabrics, and methods of making thin fibers by piercing a synthetic resin film with many needles and tearing the film, but in both cases the equipment is complicated and There were problems such as not being able to obtain complete fibers.

The object of the present invention is to solve the problems encountered in the conventional nonwoven fabric manufacturing method as described above.

That is, in this invention, by applying high-speed vibration while stretching a film formed of a thermoplastic synthetic resin with a chain-like molecular arrangement, the countless cracks that occur in the stretching direction are caused by fiber bonds made of a large number of thin fibers. A process of obtaining a bundle, a process of drafting the fiber bundle obtained in this process on a conveyor belt while giving it lateral vibration to form a web consisting of countless fibers crisscrossing each other vertically and horizontally, and a process of forming a web consisting of countless fibers intersecting each other vertically and horizontally. It consists of a heat welding process, and involves stretching a film of thermoplastic synthetic resin with a chain-like molecular arrangement, which is produced in the form of a tube or sheet from equipment such as a well-known inflation device. Existing equipment is sufficient.

If the film is stretched in this way, countless cracks will form in the direction of stretching and the formation of fibers will begin.Next, by applying high-speed vibrations such as ultrasonic vibrations in the air or water, the fibers will become extremely thin. A countless number of fibers can be obtained. In addition, the countless fibers obtained in this way are successively drafted on the conveyor belt while giving lateral vibrations to form a web consisting of countless fibers crisscrossed, making it possible to manufacture the web extremely efficiently. This web is created by applying pressure using a heat roll with uneven surfaces and welding the intersection points of each fiber at appropriate intervals, thereby creating a strong bond between the fibers and a nonwoven fabric with good air permeability. It will be done.

Hereinafter, details of the manufacturing method of the present invention will be explained based on an embodiment shown in the accompanying drawings.

Figure 1 shows an example of a film extruder, in which 1 indicates a hopper, 2
is an extrusion tube, and 3 is a nozzle.

A thermo-oJ plastic synthetic resin raw material 4 having a chain molecular arrangement such as polyethylene (CH2: CH2), polypropylene (C112: CHCl-1,), etc. is put into the hopper 1, and the screw in the extrusion cylinder 2 is rotated, and the extrusion cylinder is 2 is heated with an appropriate heating device, the particles in the hopper 1,
The raw material 4, such as a powder, enters the extrusion cylinder 2 and is heated by the heat generated by the compression and cross-wire action of the screw and the heat generated by the extrusion cylinder 2 to become molten. and is extruded. At this time, an appropriate amount of air is allowed to flow into the film 11 from the air pipe 6 to inflate it, so that the film 11 maintains its cylindrical shape and is cooled by the air inside and outside.

The cylindrical film 11 is held between a pair of upper guide plates 13 and between a pair of rolls 12 to become flat, and is wound onto a winding shaft 16 via a guide roll 15.

When the planar shape of the slit 5 of the annular nozzle 3 has the same width over the entire circumference as shown in FIG. 2, a film 11 having a constant thickness over the entire circumference can be obtained. Furthermore, if there are multiple recesses 8 inside the slit 5 as shown in FIG. 2H, the film 1
1 is formed with a plurality of protrusions. However, there are cases where the slits are straight and a planar film is extruded.

If the film 11 produced by the extruder as described above is cylindrical, it is cut open and subjected to the stretching process shown in FIGS. 3 to 5 to form a single strip.

The device for this process is a belt-shaped film 11 wound around a winding shaft 16.
is passed through a plurality of rolls 22 in a zigzag pattern, and then placed on a hot plate 23 curved in a chevron shape and stretched while being heated.

In the embodiment, this hot plate 23 is divided into four parts to control the temperature, but normally the temperature is about 130 to 200.
Since the chain molecules must be extremely aligned in one direction during stretching, a stretching ratio of 8 to 20 times is appropriate.

The film 11 that has undergone the stretching process has chain molecules lined up in the stretching direction, so the countless cracks in the stretching direction are a condition for the formation of cracks. It is bent downward by the intermediate lower roll 25 and immersed in water in a water tank 26. This underwater flea is equipped with 27 ultrasonic vibrators, which apply ultrasonic vibrations to the film 111 through water, so that the countless fissures in the film 11 are completely separated. , becomes a flat fiber bundle 21 consisting of countless fine 1/) fibers. However, there are cases where ultrasonic vibrations are applied in the air.

The fiber bundle 21 passes through a plurality of rolls 28 in a zigzag pattern,
Next, enter aspirator 29. This aspirator 29
is flat and hollow, blows out compressed air toward the outlet on the right side of Figure 3, and moves back and forth by an appropriate drive means as shown by the arrow in Figure 3. The fiber bundle 21 entering from the inlet is ejected from the left outlet together with air.

In front of the aspirator 29 is an inclined conveyor belt 30 as shown in FIG. 4, and below it is a horizontal conveyor belt 32.

Accordingly, the fiber bundle 21 that has been ejected from the aspirator 29 and descended descends while being oscillated laterally, resting on the belt 30, becoming a web 31 on the belt 32, and moving in the direction of the arrow in FIG. However, in addition to such an embodiment, a cross layer or a chain traverse may be arranged next to the aspirator 29.

As a result, the belt 32 is dropped into the hopper chamber, and from this hopper the belt 32
You can drop it on top. The web 31 that has passed through the belt 32 has diagonally crossed fibers, but in the next step this web 31 is stretched to make the thickness uniform.

The device used in this process is one in which a plurality of needle rolls 33, each having a countless number of needles planted on its outer periphery, are arranged one above the other.

The web 31 passing between the upper and lower needle rolls 33 heads for the next heat welding means in a state where the fibers thereof are caught by the numerous needles of the roll 33, keeping the width constant. Here, there is a pair of upper and lower heat rolls 34 with uneven outer peripheries.

This heat roll 34 is made of any material such as steel, cotton, rubber, etc. 1. If both rolls 34 have unevenness, the protrusions and convexities of both rolls 34 are made to match, and the concave and convexities of both rolls 34 are made to match
If one roll 34 has unevenness, the other roll 34
has no unevenness.

Each of the heat rolls 34 described above has a temperature that is high enough to melt the web 31 by electric heating or the like. Therefore, when the web 31 passes between the heat rolls 34, the fibers in the portions pressed by the protrusions 1 of the rolls 34 are crimped and welded. However, since the web 31 in the recessed portion of the roll 34 remains as it is, air permeability is not lost. In this way, the web that has passed through the hot roll 34 becomes a complete nonwoven fabric 36 and is placed on the winding shaft 35.
It is wound up.

Since this invention directly produces a nonwoven fabric using a film produced by the inflation method or the T-die method as described above, the production equipment is simple and compact, and it is suitable for small-scale production of a wide variety of products. Furthermore, since the stretching is sufficiently carried out, a thin and very strong nonwoven fabric can be obtained. Furthermore, when using a film with ridges produced using a die as shown in Figure 2 (1), it is possible to obtain a durable nonwoven fabric whose entire surface is covered with a web of thin fibers from the thick mesh fibers. There are effects such as being

The nonwoven fabric obtained by the method of this invention can be used as a base fabric for agricultural covering materials and chair lining materials.

[Brief explanation of drawings]

Figure 1 is a partially longitudinal side view of the film extruder, Figure 2 I
, ■ is an enlarged plan view showing each side of the film extrusion slit of the extruder, Fig. 3 is a front view showing an example of an apparatus for carrying out the method of this invention, Fig. 4 is a side view of the same, and Fig. 5 is the same. FIG. DESCRIPTION OF SYMBOLS 11... Film, 21... Fiber bundle, 32... Conveyance belt, 34... Heat roll. Patent applicant Nippon Nonwovens Co., Ltd. Figure 1 2 Figure 2 6

Claims (1)

[Claims] 1. By applying high-speed vibration while stretching a film made of a thermoplastic synthetic resin with a chain-like molecular arrangement, countless cracks that occur in the stretching direction are separated into a large number of thin fibers. a step of drafting the fiber bundle obtained in this step on a conveyor belt while imparting lateral vibration to form a web consisting of countless fibers crisscrossed in the vertical and horizontal directions, and the requirements for this web. A method for producing a nonwoven fabric comprising the step of thermally welding fibers together. 2. Production of a nonwoven fabric according to claim 1, wherein the high-speed vibration applied while stretching the film is applied by introducing the film to be stretched into water and using an ultrasonic vibrator installed in the water. Method. 3. The method for producing a nonwoven fabric according to claim 1, which uses a film provided with a large number of longitudinal ridges.