JPS59204960A - Production of long fiber 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 is directed to a method for producing long fiber nonwoven fabrics comprising continuous filaments of thermoplastic material.

More particularly, the present invention relates to a method for producing a long-fiber nonwoven fabric that includes the step of uniformly stretching a nonwoven web of continuous filaments substantially randomly arranged in at least one direction.

The object of the present invention is to uniformly stretch a nonwoven web in order to improve the directionality of the physical properties of the nonwoven fabric, improve the dimensional stability, and expand the width of the nonwoven web.
The purpose of this invention is to provide a method for creating JjJU.

Various methods are known for producing long fiber nonwoven fabrics made of continuous filaments of thermoplastic materials, and they are also produced industrially. Most of these methods are direct-spinning nonwoven fabric manufacturing methods called spunbond methods, in which continuous filaments are spun from a molten material, the filaments are deposited as a nonwoven web, and the filaments are bonded together. It manufactures nonwoven fabrics. However, in this method, a major problem arises because filament spinning and forming into a nonwoven web are carried out integrally and continuously. In other words, in order to obtain a filament web opened into a single filament, it is necessary to have uniformity of the basis weight. One of the most important factors is the dimensional stability of the physical properties of the cutting fabric, as well as the control of filament deposition and arrangement, which is a key factor in the properties of the nonwoven fabric, such as the width of the nonwoven fabric.

In order to control the deposition of filaments, various methods have been disclosed, such as applying the filaments and a conveying air stream to a collision plate, or using a secondary air stream or the like to shake the filaments onto a net conveyor. However, in the spunbond method, the yarn runs at high speed, and depending on the difference in speed with the moving speed of the deposited receptor, the filament draws a loop υ or bends, and is arranged at approximately two times. , it is extremely difficult to deposit a large number of filaments in a desired arrangement. In order to maintain the uniformity of the basis weight, which is essential for making a nonwoven metal product, it is impossible to improve the dimensional stability of the physical properties of the nonwoven fabric, the width of the nonwoven fabric, etc. even if it is unsatisfactory. Or, because the spinning and web-forming equipment are integrated, it cannot be easily modified and the filament arrangement is unique to a selected process.

The reality is that it is impossible to escape from a fixed web width.

For this reason, the present inventors have begun to consider a method of improving the nonwoven web after being deposited by stretching it into a desired web. It seemed extremely difficult to do. That is, methods for stretching the short fiber nonwoven fabric include, for example, a method in which an elastic adhesive is applied to the web as in t% Publication No. 43-21114;
As disclosed in Japanese Patent No. 943, a method of needle punching and elongation of Kuep after resin application is known. However, these methods themselves have problems, and in the method of applying all the resin to continuous filaments, a high elongation rate cannot be obtained unless a special resin is used. There are many problems such as difficulty in selecting the type, amount of adhesion, drying conditions, etc.

Furthermore, since it contains 41d resin, it is not a so-called non-woven inder, which limits its use as a nonwoven fabric, which is a big problem. In addition, in the method using a 21-dorno punch, the elongation rate is different between the needled joint point and other parts, and the needle pattern due to the difference in the density of the fibers after elongation becomes noticeable, resulting in poor quality. There is a problem that the product becomes inferior and cannot be put into practical use.

In view of these problems, the inventors of the present invention have conducted intensive studies on methods for producing long fiber nonwoven fabrics, and as a result, have completed the present invention.

That is, 1 the present invention provides a method for producing a long fiber nonwoven fabric composed of continuous filaments of a thermoplastic material, in which a nonwoven web of continuous filaments arranged approximately randomly is entangled between the filaments by a liquid flow, and then the filaments are entangled. Stretching the nonwoven web by 20 to 150 inches in at least one direction
This is a method for producing a long fiber nonwoven fabric.

In the present invention, the long-fiber nonwoven fabric is obtained from a nonwoven web in which continuous filaments of thermoplastic material are deposited in a generally random manner. The fact that the filaments are roughly random means that the threads traveling at high speed are deposited on a receptor moving at a slower speed, either as they are or while being rolled, and the filaments change depending on the speed difference. refers to a state in which υ is drawn in a loop, bent and partially arranged randomly, and means that it is not in a state in which, for example, ficimen F, which is a component of Toku, is aligned. Therefore, the nonwoven web of slow 0t filaments used in the present invention is not limited to one tube in this state, but can be a nonwoven web spun and deposited by a four-way spunbond method. is suitable.

Further, the filaments are usually spun-drawn fibers or fibers drawn at high speed, and have the properties of so-called drawn yarns, although the elongation of each filament is small.

In the present invention, even if the elongation rate is extremely high, it is possible to elongate the material uniformly.When elongating in one direction, the direction perpendicular to the elongation is fixed to 80-100%, and by shrinking the material in one orthogonal direction, the material can be reduced by 100-150%. Elongation can be easily obtained. Naturally, the present invention.

It is also possible to apply it to so-called undrawn filaments other than drawn yarn, such as drawn yarn, and it also includes mixing short fibers to enhance the entangling effect by liquid flow and improve surface properties. good.

As the thermoplastic material r='fA that becomes the continuous filaments constituting the nonwoven web, a homopolymer or a copolymer of polyamide, polyester, or polyolefin is selected, and a mixture thereof may be used. The filament is not particularly limited either, and may be a single component or a multicomponent system containing two or more components, and may be a so-called composite filament or a mixed filament. The shape of the filament may be any shape, such as a perfect circle, ellipse, flattened, triangular, or hollow. The fineness is also not particularly limited and is selected between 0.1 and 20 deniers, preferably 0.1 to 20 deniers.
It ranges from 5 to 10 deniers. There is also no limit to the basis weight of the nonwoven web, and it depends on the material and fiber diameter, but it is 10 to 15 (1
/nr range is suitable.

In the present invention, in order to uniformly elongate these nonwoven webs, a process of entangling the filaments of a web of continuous filaments arranged generally at random with a liquid flow is included.

That is, a large number of small interlacing points are created in the nonwoven web.

Even if the random fibers between the intertwined points are stretched out by elongation, the intertwined points do not become noticeable, and in advanced elongation, these small intertwined points are gradually loosened, so that the fibers are uniformly distributed without any unevenness. By changing the arrangement of filaments in a woven web as desired, a nonwoven fabric with excellent physical properties can be obtained. For this purpose, it is necessary to increase the entanglement strength of the nonwoven web by applying a liquid flow, and the tensile strength at break in the elongation direction is 5°1/2.
It is preferable that the width is at least IK9/3 (1) in terms of male size. Although it is possible to elongate a nonwoven web with an entanglement strength lower than this, it has been found that uniform elongation is difficult in areas where the elongation rate is high, and unevenness occurs. In order to obtain this entanglement strength, any method of entanglement using a liquid stream may be used, and preferably a high-pressure liquid with a pressure of 10 Kt/dG or more is used as the liquid stream, and a nozzle that turns this into a columnar flow or a diffusion flow. An entangled state is obtained by discharging the material and acting on the nonwoven web.

In this case, the nonwoven web must have a degree of freedom in which the filaments can be moved by the liquid flow, so that the filaments can remain deposited or be treated even if the liquid flow The fibers can partially move due to the action of Furthermore, it is necessary to limit the processing to a degree that allows for entanglement. Therefore, treatments that involve bonding with resins that are insoluble in the liquid stream used or complete fusion between fibers should be avoided.

Any method may be used to treat the fibers with a liquid stream, such as a columnar stream or a diffuse stream directly impinging on the web. Alternatively, a method may be adopted in which inclusions such as gold and copper are present to cause partial collision. Also,
It is also possible to create a patterned entangled web by slightly moving the filaments using a screen under the web, etc. Depending on the size or strength of the pattern, it is possible to create a web with a pattern remaining or no pattern by stretching. Making it a thing is also optional. If the web has a normal gold 11i4 pattern or a columnar flow stripe pattern, it can be made into a plain nonwoven web with no pattern and a wide range of uses by subsequent elongation.

In the present invention, the interlaced web is stretched 20-150 inches in at least one direction. The direction of elongation is not particularly limited and may be taken arbitrarily depending on the purpose. Therefore, the elongation of the nonwoven web is controlled in the machine direction (M
D) or cross machine direction (CD),
This includes stretching in one direction, such as fixing or contracting the direction perpendicular thereto, and stretching in two directions, the entire MD and CD, simultaneously or sequentially. Any conventionally known methods and devices may be used for this purpose, and methods and devices used for stretching ordinary textiles, knitted fabrics, and films are suitable, and stretching machines using rolls with different speeds are suitable. , a pin tenter, a clip tenter, a biaxial tenter, etc. can be used to elongate in one direction or in two directions simultaneously or sequentially.

The temperature at which this nonwoven web is stretched can be arbitrarily set as long as it is below the melting point of the fibrous material. The stress of the stretched nonwoven web is mainly due to the entanglement between the fibers, and is not greatly affected by temperature, and stretching at room temperature is possible. However, in the case of a high degree of elongation, from the viewpoint of setting properties and uniform elongation properties after elongation, the temperature is preferably from above the glass transition point of the fiber to below the melting point of 10°C. Furthermore, when a water stream is used for the entanglement, it is also recommended as a preferred method from an industrial standpoint to simultaneously dry and elongate the adhering water.

When stretching a nonwoven fabric, it is essential to stretch it uniformly, and for this purpose, it is preferable that the basis weight before stretching is uniform and that the entire fabric is stretched uniformly. However, when a nonwoven web with uneven fabric weight is stretched, areas with low fiber density, ie, low fabric weight, tend to be stretched intensively, resulting in a nonwoven web with larger uneven fabric weight than the original nonwoven web. Even in webs produced by the spunbond method, some unevenness in area weight is inevitable, and stretching methods that promote this are undesirable, and the present invention can be an excellent method in this respect. That is, in the entanglement of fibers by fluid,
Since entanglement occurs due to the energy of the fluid, the smaller the fabric weight of the nonwoven web, the greater the entanglement strength at individual interlacing points. Therefore, the stretching method of the present invention is aimed at eliminating the increase in fabric unevenness due to stretching. As a result, a nonwoven fabric with a uniform basis weight can be produced.

By carrying out the present invention, it is possible to easily improve the nonwoven web obtained by the spunbond method, and it becomes possible to manufacture nonwoven fabrics with various characteristics from a uniformly manufactured nonwoven web. For example, due to the method of dispersion and deposition of filaments, the filaments are generally random but are generally arranged in MDK, resulting in weak CD strength, or arranged in CD, resulting in low MD strength. It is easy to improve the properties to obtain isotropic nonwoven fabrics, or conversely to strengthen the anisotropy to make nonwoven fabrics for tapes and belts. Furthermore, by stretching in one direction or two directions, loop-shaped or bent filaments are stretched in the stretching direction, resulting in a dimensionally stable nonwoven fabric. Furthermore, the non-woven web is
The ability to arbitrarily obtain a nonwoven fabric with a desired width that is wider than the spun filament web by DK stretching is very effective for the spunbond method and shows the great effect of the present invention.

A nonwoven web entangled and uniformly stretched by a liquid flow in this manner can be used for various purposes by taking advantage of its excellent properties. To this end, various steps may be included to subject the elongated nonwoven web to various treatments. That is, the elongated web according to the present invention has interlaced points and maintains its shape even as it is. However, depending on the entanglement strength and elongation rate in the liquid flow, it is often preferable to add a process of joining the two filaments or adjusting the surface condition and density after the desired filament arrangement.
These can be adopted arbitrarily.

In other words, there are methods such as heat fusion, reentangling with fluid, needle punching, and compressing with rolls.
Methods such as laminating, and in some cases,
Addition of resin may also be adopted depending on the application.

In the present invention, the tensile test of the nonwoven web was carried out at room temperature with a sample width of ac, a gripping length of 10Ω, and a tensile rate of 2°F/min, and the tensile strength at break was determined. In addition, in order to take into account the basis weight, the breaking strength was assumed to be proportional to the basis weight, and the converted breaking strength was 5o2/靜K9'Ji.

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

Example 1 Polyethylene terephthalate was spun at a temperature of 290°C and a pore size of 0.25. A continuous filament is formed by spinning from a rectangular spinneret with a large number of nozzle holes, and the filament is deposited on a wire mesh that is pulled and moved at high speed by a rectangular air sucker. A nonwoven web of - was obtained. This web is passed between heated rolls that have an embossed pattern on one side and a flat surface on the other. Part of the surface remains slightly sticky so that it can be wound up, but if you rub it with your fingers, the web will be completely covered. It is made of a non-woven web that will not break easily. This is a web with a uniform basis weight in which individual filaments are bent in random directions and stacked on top of other filaments. ,
It is a nonwoven web consisting of continuous filaments arranged approximately at random, and the tensile strength of -'e is 0.8 in MD.
Kg/3 crn width, CD 0.3 Kg/3 t
trr wide.

Subsequently, this nonwoven web was placed on 80 meshes of gilt bronze, treated on both sides with a columnar stream of water ejected at a pressure of 25 Kg/caG from a nozzle with a diameter of 0.2 mm to form an entangled nonwoven fabric, and dried. This tensile strength is MD is 9.7 Kg73 cm width CD
It was a nonwoven fabric that weighed 3.9 kg and had a width of 73 cm, and the streaks of columnar water flow were discernible.

When this nonwoven web was fixed in the vertical direction using a pin tenter set at 220°C and stretched by 451% in the horizontal direction, a uniformly stretched nonwoven fabric with a fabric weight of 36 f/n was obtained. Converted strength is MD 7.8 Kg/3cr
With isotropy of nCD 7.6 Kg73 cm rll,
The result was a homogeneous nonwoven fabric with no visible columnar water streaks.

Example 2 The same nonwoven web used in Example 1, which had been spun deposited, heat treated and wound, was placed on a 20 mesh gold copper plate and
30 kglcr! Five treatments were carried out using a spray nozzle dispersing high-pressure water of G. After treatment, the nonwoven web has a gold-bronze pattern and its tensile strength is MD' 3.8.
Kg73 cm 1], CD 1.6 Kg/3 c
m rlJ was 0.50° in the horizontal direction using a pin tenter set at 150°C.
After forming a homogeneous web with no pattern by elongation, partial heat-compression bonding was performed using an embossing roll, resulting in a fabric weight of 35 f/
r/converted strength is Mp 8.5 Kg73 cm width, C
An isotropic thermally bonded nonwoven fabric having a width of D 8.7'Ky/3ttr+ was obtained.

Comparative Example 1 The same nonwoven web used in Example 1, which had been spun deposited, heat treated and wound, was needle punched.

The needle density was 30 haunches/ctl and the needle depth was 10 haunches using a No. 40 felting needle, and the tensile strength was MD6.4Kg/3.
While on, it weighed 2.5 kg and was 73 cm wide.

This nonwoven web was stretched at 150°C using a pin tenter, but the fibers were strongly intertwined at the point where they were needled, and as the fibers in other areas became sparser with stretching, the difference in fiber density became clear. , the appearance was markedly inferior with irregular patterns.

Example 3 Continuous filaments were formed by spinning polyethylene terephthalate at a spinning temperature of 290° C. through four round spinnerets having nozzle holes with a diameter of 23 mm, and the filaments from each spinneret were spun into a single-twist type air sucker. While pulling the filament with a corona discharge and spreading it by corona discharge, the filament was deposited uniformly on the coarse knitted fabric fed onto the moving gold-copper so that no streaks appeared between the weights, and the fabric weight of the single yarn was 1.5 denier. A nonwoven web of 50t/rt was obtained. This nonwoven web had a generally randomly arranged fiber arrangement in which individual filaments formed large loops and overlapped with other filaments, with many fibers being arranged in the horizontal direction as a whole. The nonwoven web was peeled off from the knitted fabric and placed on a 30-mesh wire mesh, and only one side thereof was treated with a columnar water stream jetted from a nozzle with a diameter of 0.2 mm at a pressure of aoKy/dG. The tensile strength of this nonwoven web is 2.2 in MD.
It is a nonwoven web with a width of K9/a cm and a width of CD of 3.8 to 36n, with a gold-bronze pattern observed.

This nonwoven web is stretched 2 times using a film stretching roller.
After elongating the web by 40% in the longitudinal direction at 00° C. to obtain a homogeneous nonwoven web with no pattern, partial thermocompression bonding was performed using an embossing roll. The basis weight of the non-woven fabric is 39f/rrl and sb, the converted strength is MD 8.7 Kp/3 cm width, CD 8.8
It was approximately isotropic with a width of 73 cm.

Example 4 A single yarn of nylon 6 2. O
d continuous filaments are arranged approximately randomly,
A uniformly deposited nonwoven web with a basis weight of 4097xi was produced. Ao Kg/cd on 8G mesh gilt bronze
Treated with a columnar water stream ejected with a pressure of G, the converted strength is MD
4.0 Kg73 cm width, CD 9.1 K2/3c
It was made into a nonwoven web with a width of m. After stretching 100% in the vertical direction using a stretching machine at 150°C to form a homogeneous nonwoven web, the engraved roll was partially heat-pressed, resulting in a fabric weight of 25 fit and a breaking strength of MD 6-2 Kg. / 3c
Unlike the original nonwoven web, which had a width of n1 and a width of CD 3.4 Kg73 cm, the resulting nonwoven fabric had a large number of MDK #1 fibers and had extremely good dimensional stability.

Examples 5 to 8, Comparative Examples 2 to 3 Using the deposited web obtained in Example 1 and using a nonwoven web consisting of continuous filaments arranged approximately randomly, the conditions of liquid flow treatment were varied to improve the entanglement strength. Different webs were created and the entanglement strength and uniformity during elongation were investigated. As a measure of uniformity, lattice points (500 g x 500 wx) K were marked on the web before elongation with a spacing of 25, and after elongation of the CD with the MD fixed using a pin tenter, the lattice point spacing on the CD was measured. The results are shown in Table 1.

Table 1 Example 9 Polypropylene (85056 manufactured by Chisso) was spun at a temperature of 2.
It was discharged as continuous filaments from four spinnerets at 65°C. 10th wheel and 15th wheel rotating at 500m/min
Using a 20th wheel rotating at 00 m and two air suckers, the filament drawn through the 10th and 20th wheels and the unstretched filament F that had passed through only the 20th wheel were placed in each air sucker. After the filaments are mixed and introduced, the filaments discharged from the two air suckers are charged by electric discharge, and then applied to a SUS collision plate to be deposited uniformly on the moving gold copper. Single yarn with many fibers arranged in 4. By making a nonwoven web of θ denier with a basis weight of 60 f/rt and subsequently treating this web with a columnar water stream, the basis weight set
/rt The strong force converted to K is MD 4.7 help/3 width, C
A 2.2 kg/33 width intertwined nonwoven fabric was obtained.

This intertwined nonwoven fabric was held at room temperature with a pin tenter, MD was kept constant, and the CD was stretched aofb to obtain a uniform nonwoven fabric, and then thermo-compression bonded with a flat roll to obtain a fabric weight of 449.
/rl tensile strength is MD 8.111473m, CD
An isotropic nonwoven fabric having a width of 8.9%/3 cnr was obtained.

Example 10 Using the interlaced non-woven material of Example 90, with a pin tenter,
When the horizontal direction was stretched by 50 inches, the pin speed was kept constant and the feed speed was decreased, the vertical direction was also stretched by 20 inches, and when the same rolls were used to heat and press them, the fabric weight was 3.
9 t/rI? The tensile strength is MD 7.1 k/3
On width, CD 6-4 Kg/3 crn width, No. 11 was isotropic and became a homogeneous nonwoven fabric with extremely good dimensional stability.

Patent applicant: Asahi Kasei Industries, Ltd.

Claims (5)

[Claims] (1) In a method of manufacturing a long-fiber nonwoven fabric consisting of continuous filaments of a thermoplastic material, a nonwoven web of continuous filaments arranged approximately randomly is entangled between the filaments by a liquid flow, and then the nonwoven web is at least A method for manufacturing long fiber nonwoven fabric Q, which is characterized by including a step of elongating 20 to 150% in one direction. (2) By entangling the filaments,
The tensile breaking strength in the elongation direction is the basis weight sot/n! Claim 1 having a width of at least 11'473 cm in terms of conversion.
Manufacturing method described in section (3) The manufacturing method according to claim 1, in which a columnar flow or a diffusion flow from a liquid having a pressure of 1-OKg/dlG or more is used as the liquid flow. (4) The manufacturing method according to claim 1, wherein the nonwoven web is stretched in either the machine direction (MD) or the cross machine direction (CD), and the direction perpendicular thereto is fixed or contracted. (5) The manufacturing method described in item 1 of the scope of patent iii'J, in which the nonwoven web is stretched in two directions, MD and CD, and the stretching is performed simultaneously or sequentially.