JPH09228223A - Production of spun-bounded nonwoven fabric - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a spun-bonded nonwoven fabric having uniform weight distribution and excellent in texture. SOLUTION: A continuous filament group 2 obtained by melt-spinning a thermoplastic resin in reed screen-state from a spinneret 1 is drawn by a high speed stream drawing apparatus 19 having rectangular cross section. A lip 17 capable of carrying out continued minute change of shape in the long side direction of a jetting port is provided in a rectangular jetting port part in the lower part of the high-speed stream drawing apparatus and the weight of a nonwoven fabric 9 is continuously measured in the width direction of the nonwoven fabric by a weight measuring apparatus 11 and a lip of a part corresponding to a place having partially heavier weight or a place having partially lighter weight is automatically changed. Further, filament is deposited on a net conveyer 6 while uniformly keeping a filament density of the nonwoven fabric in the width direction.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for continuously producing a spunbonded nonwoven fabric composed of continuous filaments. More specifically, the present invention relates to an apparatus and method for producing a spunbonded nonwoven fabric having a uniform basis weight distribution.

[0002]

2. Description of the Related Art A spunbonded nonwoven fabric is obtained by melt-spinning a thermoplastic resin into a continuous filament group, which is thinned and drawn by using a high-speed airflow traction device to obtain a density distribution of the continuous filament group inside and outside the high-speed airflow traction device. After homogenizing,
In recent years, the demand has been increasing as a method for inexpensively obtaining a nonwoven fabric by a method of depositing this on a net conveyor to form a non-woven web. It has become important to obtain a technique for making the areal weight distribution uniform.

Various methods have been proposed for making the density distribution of the continuous filament group uniform, but the continuous filament group melt-spun in a comb shape is formed from a spinning hole arranged in a rectangular die in a rectangular shape. The method of leading to a high-speed airflow traction device having a narrow traction path and a wide rectangular cross-section has been used as a means for obtaining a wide non-woven fabric having no streaks. In this case, the continuous filament group is arranged in a comb shape in the width direction by the spinneret and the high-speed airflow traction device, which have almost the same width as the finally obtained non-woven fabric product. It is hard to say that they are uniformly dispersed due to such factors. In addition, many opening methods have been proposed for uniformly opening a continuous filament group in order to obtain a well-formed nonwoven fabric. This opening method is a method of diffusing an air flow accompanying a continuous filament group ejected from a high-speed air flow traction device and multiplying the diffusion of the air flow to disperse it, and applying a homopolar charge to the continuous filament group by friction charging and corona discharge. Many methods have been proposed, such as a method of applying and opening the fibers by the repulsive force thereof, a method of rocking the jet outlet of the continuous filament group to widen the dispersion width, and the like.

In any of these methods, it is sufficiently possible to disperse the constituent fibers of the continuous filament group individually, but the arrangement of the fibers in the local portion is disordered, and the obtained product is When looking over the whole area, it was difficult to suppress the nonuniformity of the fabric.

[0005]

[Problems to be Solved by the Invention] When a high-speed airflow traction device having a narrow cross-section and a wide rectangular cross-section is used, the continuous filaments introduced in a comb-like shape are uniformly distributed in the width direction (width direction of the nonwoven fabric). Injecting with a high-speed air stream requires sophisticated technology. For this purpose, it is necessary to finish the inside of the high-speed airflow traction device with high precision so that the shape of the injection port is not distorted over the entire width of the long side, but this requires high technology for finishing, equipment cost, Increase maintenance costs. The wider it becomes, the more noticeable it becomes. Further, the continuous filament group becomes non-uniform due to stains and thermal strains inside the high-speed air flow pulling device during operation. Therefore, the width of the injection port in the short side direction is
As a result of diligent examination as to whether it is possible to partially adjust over the entire width of the long side, a continuous lip in the long side direction of the rectangular injection port and a throttle bar for fine adjustment are attached to the rear of the lip at equal intervals, The present invention has been completed by devising a method in which the width in the direction of the short side can be finely adjusted and further linked with a basis weight measuring device.

The present invention solves the problems in the known technique for controlling the occurrence of the non-uniform weight, and it is possible to suppress the non-uniformity of the continuous filament group by a simple operation without the need to process and maintain the equipment. The present invention provides a method for producing a spunbonded nonwoven fabric having a uniform basis weight distribution.

[0007]

Means for Solving the Problem The first aspect of the present invention is a span using a high-speed airflow traction device having a rectangular cross section for thinning and stretching a continuous filament group obtained by melt-spinning a thermoplastic resin in a comb shape from a spinneret. In the method for producing a bonded non-woven fabric, a rectangular-shaped injection port portion under the high-speed airflow traction device,
At least one of the long sides of the injection port is provided with a lip and a micro-deformation device for the lip, which are formed as a continuous body in the long side direction of the rectangular injection port, and the injection port is shortened by the slight deformation of the lip. This is a method for producing a spunbonded nonwoven fabric, which comprises slightly varying the width in the side direction to adjust the basis weight. A second aspect of the present invention is characterized by comprising an apparatus capable of continuously measuring the basis weight of the non-woven fabric, and adjusting the basis weight of the non-woven fabric by slightly deforming the lip in conjunction with a signal from the device. The method for producing a spunbonded nonwoven fabric according to the first invention.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, a method for producing a spunbonded nonwoven fabric according to the present invention will be described with reference to FIGS. FIG. 1 is a side view showing an example of an apparatus used in the method for producing a spunbonded non-woven fabric of the present invention, and FIG. 2 is an enlarged view of a lip at the lower part of the high-speed airflow traction device and a device for slightly deforming the lip. FIG. 3 is a view of the high-speed airflow traction device and the injection port as viewed from below the lip.

In FIG. 1, a continuous filament group 2 discharged from a spinneret 1 passes through an ejector 3 and an air channel 4, hits a reflector plate 5, and is opened by friction charging. The opened continuous filament group 2 is accumulated in the form of a non-woven web on the wire mesh net conveyor 6,
The hot embossing roll 8 heat-bonds at a number of points to form a nonwoven fabric 9, which is wound by a winder 10.

A unit weight measuring device 11 is mounted between the hot embossing roll 8 and the winder 10. The basis weight measuring device 11 measures the basis weight over the entire width of the nonwoven fabric. The basis weight of the non-woven fabric 9 can be image-processed by the computer 12 and displayed on the monitor 18. If there is a portion which is calculated by the computer 12 and which is above the standard weight or below the standard weight, the worm 14 is rotated by the stepping motor 13 and the worm wheel 15 is rotated. Then, as the throttle bar 16 moves back and forth, the lip 17 distorts and moves back and forth. As the lip 17 moves back and forth, the width of the short side of the injection port 20 at the outlet of the air channel 4 is narrowed or widened slightly to change the air flow. As a result, the density of the continuous filament group 2 flowing inside the air channel 4 changes. For example, when the lip 17 protrudes forward, the width of the injection port 20 of the air channel 4 becomes narrow, the density of the continuous filament group 2 becomes small, and the basis weight of that portion is lowered. On the contrary, when the lip 17 is retracted, the width of the injection port 20 of the air channel 4 is expanded, the density of the continuous filament group 2 is increased, and the basis weight of that portion is increased.

The nonwoven fabric 9 whose basis weight is continuously measured by the fabric weight measuring device 11 can be automatically adjusted to a certain standard fabric weight over the entire width of the nonwoven fabric by finely adjusting the lip 17 through the computer 12. Become. The throttle bar 16 is 50 to 200 in the long side direction of the injection port 20.
It is desirable to be mounted at a mm pitch. Since the lip 17 is continuous over the entire width, even if the lip 17 is finely deformed at a pitch of less than 50 mm, the pitch is too small and the effect of the areal weight variation is small, and it is difficult to correspond to the position measured by the areal weight measuring device. . Further, if it exceeds 200 mm, the adjustment pitch is too large, so that it is difficult to adjust the strain in a small width, and it is difficult to adjust the basis weight.

As the lip micro-deformation device 21 of the present invention, a conventionally known device is used. Specific driving devices include stepping motors, servo motors, induction motors, and the like. Also, the worm gears 14, 15
Alternatively, a speed reducer using a spur gear may be used, or a planetary gear device may be used. As a method of connecting the motor and the gear, a direct connection structure such as a shaft coupling or a method such as belting is used. Alternatively, a spline or the like may be used for sliding the throttle bar back and forth. Further, the lip 17 can be slightly deformed by heating or cooling the throttle bar itself to thermally expand the throttle bar.

According to the present invention, a continuous filament group obtained by melt-spinning a thermoplastic resin in a comb shape from a spinneret is drawn by a high-speed air flow drawing device having a rectangular cross section to be thinned and drawn, and the thin film is deposited on a net conveyor. In order to obtain a non-woven web, a lip and a micro-deformation device for the lip are provided at the injection port below the high-speed airflow traction device to adjust the density of the filaments in the width direction of the non-woven fabric to make the density uniform. Since it is deposited on top, a nonwoven fabric with a uniform basis weight distribution and excellent texture can be obtained.

[0014]

【Example】

Example 1 Using the apparatus shown in FIG. 1, polypropylene having a melt flow rate of 50 was melted at a melting temperature of 230 ° C. to form a rectangular spinneret (2000 spinning holes, 10 rows, 1 row with 200 holes).
1 piece per row, length 1000mm, hole diameter 0.4mm)
Melt spinning was performed at a discharge rate of 1 g per minute per hole, and a continuous filament group was introduced into a high-speed air flow traction device disposed below the spinneret, and stretched and solidified at a speed of 4000 m / min,
A continuous filament group of about 2 denier was obtained. The basis weight of a non-woven fabric having a basis weight of 30 g / m ² heat-bonded with a hot embossing roll is continuously measured by a basis weight measuring device using radiation (Yokogawa Engineering Service Co., Ltd.), and the width direction of the non-woven fabric is determined by the measurement results. The high or low area weight was specified, and the lip under the high-speed airflow traction device was automatically and slightly deformed via a computer to automatically adjust the area weight. After the continuous filament group is ejected from the high-speed airflow traction device together with the high-speed airflow, the density of the continuous filaments is changed by minute deformation of the lip equipped with a 75 mm pitch throttle bar provided at the injection port below the high-speed airflow traction device. Then, it was deposited on a net conveyor at a speed of 67 m / min to obtain the target nonwoven fabric of 30 g / m ² .

Example 2 A Svanbond nonwoven fabric was obtained in the same manner as in Example 1 except that the pitch of the throttle bar was 150 mm. Example 3 A spunbonded nonwoven fabric was obtained in the same manner as in Example 1 except that the pitch of the throttle bar was 100 mm.

Example 4 The spunbonded non-woven fabric was released in the same manner as in Example 1 except that the interlock between the fabric weight measuring device and the lip (throttle bar) was released, and the lip was manually adjusted with reference to the data of the fabric weight measuring device. (Throttle bar pitch 75 mm). Comparative Example 1 A spunbonded nonwoven fabric was obtained in the same manner as in Example 1 except that the lip was opened (the lip was removed).

The spunbonded non-woven fabric obtained has 50 ears.
After removing each mm, a width of 30 mm and a length of 500 mm in the flow direction were cut to obtain 10 test pieces. The individual weight of each test piece is measured, the average value and the standard deviation thereof are obtained, and the CV value (%) is (standard deviation / average value) x
It is indicated by 100. The results are shown in Table 1. The smaller the CV value, the better the basis weight distribution.

[0018]

[Table 1]

As shown in Examples 1, 2, 3, and 4, the spunbonded nonwoven fabric produced by the method of the present invention had a small CV value (%) and a uniform basis weight distribution. On the other hand, as shown in Comparative Example 1, the spunbonded non-woven fabric obtained by the non-invention had a large CV value (%) and a non-uniform basis weight distribution.

[0020]

EFFECTS OF THE INVENTION The method for producing a spunbonded nonwoven fabric according to the present invention comprises a rectangular cross section of a high speed airflow traction device for thinning and stretching a continuous filament group obtained by melt-spinning a thermoplastic resin into a comb shape from a spinneret. Since the rectangular ejection port portion is provided with a lip that can be slightly deformed continuously in the long side direction of the ejection port, the width of the ejection port in the short side direction can be finely adjusted, and the basis weight adjustment is easy to perform. In addition, the fabric weight of the nonwoven fabric is continuously measured in the width direction of the nonwoven fabric with a fabric weight measuring device,
The lip of the part corresponding to a part with a lot of basis weight or a part with a little basis weight is automatically deformed to adjust the basis weight. It can deal with dirt and heat distortion of the cross section, and can obtain a spunbonded non-woven fabric with a uniform basis weight distribution in a short time without requiring manpower.

[Brief description of drawings]

FIG. 1 is a side view schematically showing an example of an apparatus used in the method for producing a spunbonded nonwoven fabric of the present invention.

FIG. 2 is an enlarged view of a lip portion under a high-speed airflow traction device and a device for slightly deforming a lip used in the method for producing a spunbonded nonwoven fabric of the present invention.

FIG. 3 is a view of the high-speed airflow traction device and the injection port as viewed from below the lip.

[Explanation of symbols]

 1; Spinneret 2; Continuous Filament Group 3; Ejector 4; Air Channel 5; Reflector 6; Net Conveyor 7; Nonwoven Web 8; Hot Embossing Roll 9; Nonwoven Fabric 10; Winder 11; 13; stepping motor 14; worm 15; worm wheel 16; throttle bar 17; lip 18; monitor 19; high-speed airflow traction device 20; injection port 21; lip micro-deformation device 22; take-up roll

Claims (2)

[Claims] 1. A method for producing a spunbonded non-woven fabric using a high-speed airflow traction device having a rectangular cross section for thinning and stretching a continuous filament group in which a thermoplastic resin is melt-spun in a comb shape from a spinneret. In the rectangular injection port portion at the lower part of the traction device, a lip and a micro-deformation device for the lip, which are made of a continuous body in the long side direction of the rectangular injection port, are provided on at least one of the long sides of the injection port. A method for producing a spunbonded non-woven fabric, characterized in that the width of the injection port in the short side direction is partially slightly changed by minute deformation of the lip to adjust the areal weight. 2. A unit for measuring the basis weight of a nonwoven fabric is provided, and the unit weight of the nonwoven fabric is adjusted by slightly deforming the lip in conjunction with a signal from the device. Item 2. A method for producing a spunbond nonwoven fabric according to Item 1.