JPS58174668A - 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, and more specifically, a method for producing a nonwoven fabric using a thermocompression bonding method using a web made of a thermoplastic fine fiber and at least one type of fiber mixed therewith as a raw material. The present invention relates to a method for manufacturing a nonwoven fabric, which is characterized by using ultrasonic irradiation as a technique for manufacturing the nonwoven fabric.

Conventionally, thermo-compression bonding has been used to produce thermoplastic fibers alone or composite fibers containing at least one type of fiber.

As a method for producing a nonwoven fabric made of a web containing low melting point fibers such as copolymer fibers and unstretched fibers, belt EElt
The belt crimping method, the embossed calendar method, the hot air melt bonding method, etc. are widely used, but each has its advantages, but there are also many drawbacks (which have been pointed out). In this case, belt meandering, web being caught and wrapped around the belt due to static electricity generation, frequent cleaning due to accumulation of molten fiber residue on the belt surface, and deterioration and brittleness of the belt were observed, and it was clearly worn out. Moreover, in the belt method, the pressing force is inevitably insufficient, and sufficient strength cannot be obtained due to insufficient adhesion of the nonwoven fabric. One of the reasons for this is that the manufacturing cost of the rolls is very high.In other words, when manufacturing nonwoven fabrics using the emboss calendar method, the so-called roller linear pressure must be 10 to 50 kg/C1s in order to achieve perfect thermal bonding. is necessary,
In order to achieve uniform pressure bonding in the width direction, the roller structure must be modified using more advanced techniques to bend the embossed calendar roll, such as forced circulation of oil to the inner surface of the roller, pressing by a hydraulic element from the inner surface of the roller, or the inner surface of the roller. The equipment must be equipped with a backing plate, etc., which naturally results in extremely high equipment costs.Furthermore, the law stipulates that the heat source for heating must be electric, kerosene-burning, Regardless of which method is adopted, such as the heat circulation method, the surface structure of the embossed calendar roll and the large amount of heat loss (energy)
It may be pointed out that this is necessary. Furthermore, the hot air bonding method also requires high power costs including a heat source, a hot air circulation fan, an exhaust fan, etc., and the installation area of the equipment is large.

As described above, the current manufacturing process for nonwoven fabrics using thermocompression bonding has many problems, such as difficulty in obtaining a specified pressure bonding force, high equipment costs, high maintenance costs, and high energy costs. It must be said that it is essential to consider these items in the future.

The present invention utilizes the fact that local heating of the target object is possible due to the ultrasonic irradiation cycle, and simultaneously presses the ultrasonic oscillator (horn) with an air cylinder to heat the web. The non-woven fabric is produced by thermocompression bonding.

Below, a method for manufacturing a nonwoven fabric according to the method of the present invention will be described using drawings that are an example. In FIG. 1, a web 4 with a basis weight of 20 fpW or more and 200 dollars/preferably 50 or more years old or more than 150 years old is placed between an anvil roller 3 and an ultrasonic oscillator (horn) 2 by a feed roller 7 or a conveyor 8. Supplied, Kokote wafer 15,0
00 H2S ~25,000 H28 Noboru L, <
Ha1B, ODD BZ8~22. The horn itself is irradiated with a frequently used ultrasonic wave having a frequency of ODD 1 IZ 8 and is crimped by an air cylinder 1, and pressure is applied between the horn and the carved crest of the anvil roller.
44/, -7 or more, the web receives high energy and is locally heated, and the thermoplastic fibers in the web soften or melt due to the heat, and are pressurized in this state. Adhesion between the fibers occurs and a non-woven fabric 5 is instantly formed. The adhesion processing time (bonding time) at this time is 0.02
It takes more than seconds, which corresponds to about 80 seconds or less in terms of web running speed. Thereafter, it is sent to a winding device by a feed roller 6.

The nonwoven fabric of the present invention is manufactured by such a method, but when irradiating ultrasonic waves with a certain natural frequency, the pressing force by the horn and the processing time therein, that is, the bonding time, are important factors. Its practical significance will be explained using examples.

Parallel web of 100% polypropylene (fabric weight approximately 50 cm) and unstretched polypropylene fiber (polypro binder fiber, @) in the shadow of 70 fully drawn polypropylene fibers with approximately the same fabric weight
Prepare a mixture of SO%, 1 each with a horn pressing force of 0.31%/! -(frequency 20,
Attempts were made to produce nonwoven fabrics using a bonding time of 0.01 seconds, but the tensile strength of the resulting nonwoven fabrics was so low that they could not be used for specific purposes. Therefore, when this pressing force was set to 0.41 and the bonding time was increased by more than twice, the desired product was obtained. As can be seen from Tables 1 and 2, it is not possible to form the desired nonwoven fabric just by softening and melting the thermoplastic fibers constituting the web by irradiation with ultrasonic waves.
It was found that by applying a pressing force of 4 #A and taking a bonding time of 0.02 seconds or more, a nonwoven fabric with a predetermined performance could be obtained. However, even though the same thermoplastic is delicate, the melting point of polypropylene (165℃
Polyester has a melting point of 255°C (~173°C).
260° C.), and the bonding time is about three times that of polypropylene even if processed with the same oscillation output and the same pressing force, so it goes without saying that there is no big difference. Note that this phenomenon also tends to be the same in the case of blended fabrics of rayon, which does not have thermoplasticity, and thermoplastic fine fiber.

In addition, in Example 4, the web was slightly moistened with water spray before the treatment according to the present invention, and in Example 5, the web was similarly sprayed with thermosetting resin before the treatment. I did it. In addition, flexibility measurement c)i
andle -0-Meter.

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[Brief explanation of the drawing]

FIG. 1 shows a schematic diagram of one embodiment of the present invention, in which the web 4 is an ultrasonic oscillator (horn).
A portion of the fibers constituting the web are partially bonded in a short time while being pressed by a horn between the web 2 and the anvil roller 3. Patent applicant Ken Honda, representative patent attorney of Kurarechi Copy Co., Ltd.

Claims (1)

[Claims] 1) Applying ultrasonic waves to a web containing thermoplastic fibers while pressing the web with a pressing force of 0.41 or more using an oscillator, and applying the process for a bonding time of 0.02 seconds or more. A method for producing a bulky and flexible nonwoven fabric. 2) In the preceding paragraph, the method for producing a nonwoven fabric in which the main component of the web structure is thermoplastic fibers. ! 5) In IrllJj, a method for producing a nonwoven fabric in which the thermoplastic fiber is selected from the group consisting of polypropylene 1iiiI pongee, polyester fiber, and polyamide fiber. 4) For each item number ζ, thermoplastic tiA#l! A method for producing a nonwoven fabric that is completely wind-stretched, fully oriented thermoplastic fibers, and contains fibers with a lower melting point than the main fibers as a small amount of fibers. 6) In the previous section, the low melting point fiber is unstretched, incompletely stretched fiber, or copolymerized! A method for producing a nonwoven fabric selected from the group consisting of I fibers, composite spun fibers, and mixed spun fibers. 7) The method for producing a nonwoven fabric according to claim 5, wherein the main fiber content is 70% or more. 8) The method for producing a nonwoven fabric according to the preceding item, wherein the main fibers are fully drawn polypropylene 411IIA and the minor fibers are undrawn or incompletely drawn polypropylene fibers. 9) The method for producing a nonwoven fabric according to claim 7, wherein the main fibers are fully drawn polyester fibers and the minor fibers are isophthalic acid copolymerized polyethylene terephthalate fibers. 10) The method for producing a nonwoven fabric according to claim 1, wherein the main fiber is rayon, and a small amount of ms is thermoplastic fiber. 11) The method for producing a nonwoven fabric according to the above item, wherein the thermoplastic fibers are polyolefin composite spun 1i14 fibers. 12) The method for producing a nonwoven fabric according to the preceding item, wherein the composite spun fiber is eccentric composite spun fine, the core component is polypropylene, and the sheath component is polyethylene. 15) In each of the preceding items, the method for producing a nonwoven fabric in which the web is selected from the group consisting of a parallel web formed from a card, a random web formed from a random web, and a random web formed from a random univer. 14) The method for producing a nonwoven fabric according to the preceding item, wherein the nonwoven fabric has a date of 20 to 200 degrees. 1 person) In the preceding item, the method for producing a nonwoven fabric having a basis weight of SO to 150-.