JP2001303420A - Method for producing highly uniform nonwoven fabric and device therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a highly uniform nonwoven fabric, by which the nonwoven fabric having good uniformity can be produced in good productivity even in a production condition for thinning the fibers, and to provide a device therefor. SOLUTION: This method and device for producing the highly uniform nonwoven fabric, comprising melt-spinning a synthetic resin with a spinneret having many nozzles, drawing the obtained blind-like filament group with a high speed gas flow by the use of a high speed gas flow drawing device, blowing the gas flow on the surface of a lower horizontally moved collector to form the nonwoven fabric web thereon, and then interlacing the web, characterized in that the number (n) of the nozzles per the lateral length [m] of the spinneret and the longitudinal width (t) [mm] of a filament guide in the high speed gas flow drawing device satisfy the expression: (n/t)<=250.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for continuously producing a nonwoven fabric made of synthetic resin filaments. More specifically, the present invention relates to a method and an apparatus for producing a nonwoven fabric having fine fibers and high uniformity.

[0002]

2. Description of the Related Art A collector (usually a wire mesh) which pulls a group of filaments led from a spinneret by a filament group pulling device (usually a so-called air soccer is often used) and moves below the same. Conveyor is used)
A method for producing a nonwoven fabric by continuously forming a nonwoven web by spraying on a surface of the nonwoven fabric and then performing entanglement treatment is well known.

[0003] In particular, a filament made of synthetic resin melt-spun using a spinneret provided with a large number of nozzles,
The method of forming a nonwoven web by pulling with a high-speed airflow traction device and spraying it on a collection surface, that is, the spunbond method, in which filaments in the web are uniformly distributed, the productivity is high, and the production cost is low It is widely used because of its low cost.

By the way, the nonwoven fabric obtained by the above-mentioned method is excellent in strength, but has a problem that flexibility and water resistance are not sufficient depending on applications. Therefore, in order to improve the tactile sensation and the water resistance of the nonwoven fabric, there is a demand for a nonwoven fabric having a finer fiber. Conventionally, as a method for thinning the fiber, a method of reducing the extrusion amount from a spinneret or increasing the air velocity in a high-speed airflow traction device has been adopted.

[0005] The method of reducing the amount of extrusion from the spinneret is not preferable because the production amount is reduced. On the other hand, in the method of increasing the air speed in the high-speed airflow traction device,
Although there is an effect of thinning the fibers by increasing the air velocity, the filaments are entangled with each other to easily form a yarn bundle, which deteriorates the appearance of the obtained nonwoven fabric and causes poor uniformity. In addition, thickness unevenness is likely to occur as the air speed increases.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to provide a method and an apparatus for producing a nonwoven fabric which has good uniformity and good productivity even under production conditions in which the fibers become thin.

[0007]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to achieve the above object, and as a result, a specific relationship has been found between the number of nozzles of a spinneret and the width of a filament guide path of a high-speed airflow traction device. It has been found that a nonwoven fabric with extremely excellent uniformity can be obtained by using an apparatus having the above formula, and the present invention has been completed.

That is, the method for producing a highly uniform nonwoven fabric according to the present invention is characterized in that a group of interdigital filaments obtained by melt-spinning a synthetic resin using a spinneret having a large number of nozzles is converted to a high-speed airflow by a high-speed airflow pulling device. In a method of producing a nonwoven fabric by forming a nonwoven web by spraying on a surface of a collector horizontally moving below the collector by horizontally pulling the nozzle, the number of nozzles is adjusted per 1 m of a lateral length of a spinneret. n [pieces], (n / t) ≦ 250, where t [mm] is the vertical width of the filament guide path in the high-speed airflow traction device.
It is characterized by the following.

Further, the apparatus for producing a highly uniform nonwoven fabric according to the present invention comprises a spinneret having a number of nozzles for melt-spinning a synthetic resin, and a group of interdigital filaments spun from the spinneret. A high-speed airflow traction device for traction by an airflow, a horizontally moving collector for collecting a group of filaments drawn and blown downward therefrom to form a nonwoven web, and an entanglement processing device for entanglement of the nonwoven web The number of nozzles is n [pieces] per 1 m of the lateral length of the spinneret, and the longitudinal width of the filament guide path in the high-speed airflow traction device is t.
When [mm], (n / t) ≦ 250.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described with reference to the drawings. FIG. 1 is a schematic perspective view showing an embodiment of manufacturing a nonwoven fabric web by the method of the present invention. FIG. 2 shows A-
It is a longitudinal cross-sectional view of the high-speed airflow traction apparatus which follows the A 'line.

In FIGS. 1 and 2, a filament group 2 obtained by spinning a molten synthetic resin from a spinneret 1 having a number of nozzles is cooled, and then a high-speed airflow traction device incorporating an air jet is provided. 3, it is introduced in a screen. The high-speed airflow traction device has a filament guideway 4 having a rectangular cross section for guiding the interdigital filament group, and a slit 5 for injecting high-speed air for pulling the filament group from both sides of the guideway, The filament group pulled by the high-speed airflow pulling device is discharged from the discharge port 6 in a blind state, and is deposited on a collector 7 moving at a constant speed to form a nonwoven fabric web 8. Thereafter, the nonwoven fabric web is guided to an untangling treatment device (not shown) to be entangled to obtain a nonwoven product.

As the synthetic resin to be melt-spun, thermoplastic polymers such as polyolefins, polyamides and polyesters are preferably used. Among them, polyolefins,
The nonwoven fabric obtained is preferred because it has a low melting point and is easy to mold, and the resulting nonwoven fabric is flexible. In particular, a polypropylene resin is particularly preferred because it has an excellent balance between flexibility and strength.

The spinneret usually has a width of 10 in the vertical direction.
0-500mm, horizontal length is usually 100-6000
Within a rectangular area of mm, one having a number of nozzles arranged in the tens to hundreds of rows (normally 20 to 250 rows) in the vertical direction and a large number of nozzles in the horizontal direction is used. In the present invention, the number of nozzles of the spinneret is
The number of nozzles of the entire spinneret is [n × spinner length [m]] since the number of nozzles is expressed as n per meter in the lateral direction length. The hole diameter of the nozzle is usually 0.2 to 1.0 mmφ, and the resin discharge amount of a single hole is selected in the range of 0.1 to 2.0 g / min. In the present invention, the vertical direction is a direction parallel to the flow direction of the nonwoven fabric web, and the horizontal direction is a direction orthogonal to the direction.

The spun filament group 2 is introduced into a high-speed airflow traction device 3 having a built-in air jet in an interdigitated manner. During this time, the filament group may be an open type that is cooled by being exposed to the outside air, or a closed type that is closed and cooled by a temperature-controlled air flow.

The high-speed airflow traction device 3 has a guideway 4 having a narrow rectangular cross section as shown in FIGS. 1 and 2, and directs air from both sides of the guideway toward the traveling direction of the filament group at a high speed and at an acute angle. It is preferable to have a slit 5 for ejecting the filament by injecting the filament. In the present invention, the vertical width t [mm] of the filament guide path is (n / t) ≦ 2.
50, preferably (n / t) ≦ 200, more preferably (n / t) ≦ 150, particularly preferably (n / t) ≦ 100. It is. The drawn filament has a predetermined fineness,
It is given physical properties such as strength and discharged from the outlet 6 together with the airflow.

The speed of the high-speed air flow injected from the slit 5 is preferably high in order to make the fibers thinner. However, if the speed is too high, thread breakage is likely to occur, and stable production becomes difficult.
Although the speed in the guide path of the high-speed airflow traction device depends on the spinning speed, it is usually 1000 to 8000 m / min, preferably 1 to 8000 m / min.
It is selected in the range of 500 to 6000 m / min.

The filaments discharged together with the air stream from the discharge port are deposited on a collector 7 moving at a constant speed to form a nonwoven web 8. As the collector, a collector (usually a wire mesh conveyor) having a structure for permeating the air flow from the outlet and collecting the filament group is used. It is preferable to provide an air suction device below the collector.

Thereafter, the nonwoven fabric web is guided to a entanglement processing device (not shown) and entangled. The method of confounding processing is
A method of fusing fibers by hot embossing using an embossing roll, a method of fusing fibers by ultrasonic waves, a method of entanglement of fibers using a water jet, a method of fusing fibers by hot air through, and a needle punch And a method of entanglement of the fibers using the same is not particularly limited.

Of these, hot embossing is preferred in that a high-strength nonwoven fabric can be obtained. The embossed area ratio (engraved area ratio: the ratio of the thermocompression-bonded portion in the nonwoven fabric) in the hot embossing can be appropriately determined according to the application, but usually within a range of 5 to 40%, the strength and flexibility are increased. A nonwoven fabric with a good balance of properties can be obtained.

The nonwoven fabric obtained by the production method using the above-described apparatus has extremely excellent uniformity. In particular, even if the production conditions for thinning the fiber, that is, the airflow velocity in the high-speed airflow traction device, are increased, it is difficult to cause poor uniformity. Therefore, it is possible to make fine denier (about several deniers). In addition, the nonwoven fabric has excellent strength, flexibility and water resistance (high water resistance).

[0021]

EXAMPLES The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to the following embodiments.

The measuring methods and evaluation methods employed in the examples are as follows. Water resistance A method of JIS L1092: Measured according to the low water pressure method. The number of yarn bundles in which filaments in the plane of the obtained nonwoven fabric were entangled was visually measured, and the nonwoven fabric area was 30 cm.
It was expressed per corner and evaluated as follows. ◎ ・ ・ ・ No thread bundle can be seen, ○ to ◎ ・ ・ ・ 1 to 5 thread / 30 cm square, ○ ・ ・ ・ 6 to 10 thread / 30 cm square, △ ・ ・ ・11 to 20 yarns / 30 cm square, x: The yarn bundle exceeds 20 yarns / 30 cm square.

(Example 1) Melt flow rate (AST)
Load 2.16 kg, 230 ° C according to MD1238
The melt spinning was performed by a spun bond method using polypropylene of 60 g / 10 min. First, a polypropylene resin was melted at 200 ° C., and was discharged at a rate of 0.4 g / min per single hole from a spinneret having 4,000 nozzles having a hole diameter of 0.5 mmφ per 1 m in the horizontal direction to spin out a filament group. Cooling of the filament is performed in an open type,
The filament was introduced into the air soccer (the vertical width of the guideway was 20 mm), and the filament was pulled at an air speed of 3000 m / min in the guideway. Collect on a collecting net conveyor,
A nonwoven web having a fineness of 2 denier and a basis weight of 20 g / m ² was obtained.

Next, the obtained nonwoven fabric web is
Embossing (20% embossing area ratio) was performed with an embossing roll at 50 ° C. and a linear pressure of 50 kg / m to obtain a spunbonded nonwoven fabric. Evaluation was performed using this nonwoven fabric. Table 1 shows the results.

(Example 2) A spunbonded nonwoven fabric was manufactured in the same manner as in Example 1 except that the width of the guide path of the air soccer was 27 mm. Table 1 shows the evaluation results of the nonwoven fabric. (Example 3) A spunbonded nonwoven fabric was manufactured in the same manner as in Example 1 except that the width of the guide path of the air soccer was changed to 80 mm. Table 1 shows the evaluation results of the nonwoven fabric. (Example 4) A spunbonded nonwoven fabric was manufactured in the same manner as in Example 1 except that the width of the guide path of the air soccer was set to 40 mm. Table 1 shows the evaluation results of the nonwoven fabric.

Comparative Example 1 A spunbonded nonwoven fabric was manufactured in the same manner as in Example 1 except that the width of the guide path of the air soccer was set to 13 mm. Table 1 shows the evaluation results of the nonwoven fabric.

Example 5 Using the same polypropylene as in Example 1, melt spinning was performed by a spun bond method. Melt polypropylene resin at 200 ° C, pore size 0.5mm
The filament group was spun out at 0.4 g / min per single hole from a spinneret having 2,000 nozzles of φ per horizontal length of 1 m. Cooling of filament is performed by open type, air soccer (width of guideway 40 mm in vertical direction)
And the filament was pulled at an air speed of 3000 m / min in the guideway. It was collected on a collecting net conveyor to obtain a nonwoven fabric web having a fineness of 2 denier and a basis weight of 20 g / m ² . The obtained nonwoven fabric web was embossed in the same manner as in Example 1 to obtain a spunbonded nonwoven fabric. Table 1 shows the evaluation results of the nonwoven fabric.

Example 6 The discharge rate per single hole of the spinneret was 0.8 g / min, and the air velocity in the guide path was 6000.
A spunbonded nonwoven fabric was manufactured in the same manner as in Example 1 except that the rate was set to m / min. Table 1 shows the evaluation results of this nonwoven fabric.
Shown in (Example 7) A spunbonded nonwoven fabric was manufactured in the same manner as in Example 6, except that the width of the guide path of the air soccer was 27 mm. Table 1 shows the evaluation results of the nonwoven fabric. (Example 8) A spunbonded nonwoven fabric was manufactured in the same manner as in Example 6, except that the width of the guide path of the air soccer was changed to 80 mm. Table 1 shows the evaluation results of the nonwoven fabric.

Comparative Example 2 A spunbonded nonwoven fabric was manufactured in the same manner as in Example 6, except that the width of the guide path of the air soccer was changed to 13 mm. Table 1 shows the evaluation results of the nonwoven fabric.

[0030]

[Table 1]

[0031]

According to the method for producing a nonwoven fabric of the present invention, a highly uniform nonwoven fabric having extremely good uniformity and excellent strength, flexibility and water resistance can be obtained. Further, with the nonwoven fabric manufacturing apparatus of the present invention, the airflow velocity in the high-speed airflow traction device can be increased without reducing the production speed, and the nonwoven fabric made of fine denier filaments can be efficiently produced.

[Brief description of the drawings]

FIG. 1 is a schematic perspective view showing an embodiment of producing a nonwoven fabric web by the method of the present invention.

FIG. 2 is a vertical sectional view of the high-speed airflow traction device taken along line AA ′ of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Spinneret 2 Filament group 3 High-speed airflow traction device 4 Guideway 5 Slit 6 Discharge port 7 Collector 8 Nonwoven fabric web

Claims (2)

[Claims] 1. A group of interdigital filaments obtained by melt-spinning a synthetic resin using a spinneret having a number of nozzles, is drawn by a high-speed airflow pulling device using a high-speed airflow, and is horizontally moved below it. In the method of forming a nonwoven web by spraying on the surface of the collector to be entangled and producing a nonwoven fabric by entanglement, the number of nozzles is set to 1 m in the lateral length of the spinneret.
(N / t) ≦ 2, where n [pieces] and t [mm] is the vertical width of the filament guide path in the high-speed airflow traction device.
50. A method for producing a highly uniform nonwoven fabric, wherein the nonwoven fabric has a thickness of 50. 2. A spinneret having a plurality of nozzles for melt-spinning a synthetic resin, a high-speed airflow pulling device for pulling an interdigital filament group spun from the spinneret by a high-speed airflow, and An apparatus for manufacturing a nonwoven fabric, comprising a horizontally moving collector for collecting a group of filaments drawn and blown downward to form a nonwoven web, and an entanglement treatment device for entanglement of the nonwoven web, comprising: N per meter in the lateral direction of the spinneret
[Unit], when the vertical width of the filament guide path in the high-speed airflow traction device is t [mm], (n / t) ≦ 250
An apparatus for producing a highly uniform nonwoven fabric, characterized in that: