JP2001181957A - Method for producing nonwoven fabric from continuous filament - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a continuous filament nonwoven fabric that can be stably and efficiently fibrillated and drawn and shows high homogeneity and good in filament group opening and dispersion. SOLUTION: When the groups of a plurality of continuous filaments are melt-extruded from spinning nozzles, fibrillated and then drawn by the friction pulling force to give the objective nonwoven fabric, the continuous filaments are pulled with a high-speed fluid to which a vibration of 0.1-60 Hz is applied to produce the objective continuous filament nonwoven fabric with a filament fineness of 0.1-22 dtex.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for efficiently thinning and stretching a continuous filament group by frictional traction of a high-speed fluid to which vibration is applied, and to reduce frictional charging by a collision plate, forced charging by corona discharge, or air flow. The present invention relates to a method for producing a long-fiber nonwoven fabric by utilizing the fiber opening, dispersion, and delivery on a collecting surface such as a net conveyor.

[0002]

2. Description of the Related Art Spunbonded nonwoven fabric, which is a long-fiber nonwoven fabric, introduces a large number of continuous filaments discharged from a spinning nozzle of a thermoplastic resin into an ejector (air soccer) or the like which is a high-speed fluid pulling device, and forms a high-speed fluid. The continuous filament group is opened and dispersed by using static electricity or air flow to form a uniform nonwoven web, which is then thermocompression-bonded.

[0003] In WO97 / 35053, the air is made turbulent by adopting a unique ejector shape. At the same time, by shortening the distance between the nozzle and the ejector, the fiber is efficiently thinned and stretched by utilizing the oscillating yarn caused by turbulence at a high fiber temperature, and then dispersed on a net conveyor. Forming a woven web. However, with this method, it is difficult to obtain a stable yarn swing, and although efficient thinning and drawing can be performed, web homogeneity is poor.

[0004] US Pat. No. 5,405,559, US Pat.
No. 993, US Pat. No. 5,523,033, concerning a method for producing a melt blown nonwoven fabric, by applying vibration to a high-temperature, high-speed fluid in order to thin and stretch a thermoplastic resin,
There is disclosed a method capable of reducing the fiber diameter by about 5 to 40% as compared with a conventional case of a high-temperature and high-speed fluid that does not impart vibration. However, in this method, the molten thermoplastic resin is merely blown off by a high-temperature, high-speed fluid and entangled, and therefore has poor mechanical properties.

[0005] When producing a spunbonded nonwoven fabric of a long-fiber nonwoven fabric, it is required to make the filament thin in order to improve productivity and quality. Therefore, conventionally, (1) a method in which the fluid pressure supplied to the ejector is increased to increase the fluid flow rate and strongly pull the filament. (2) A method of shortening the distance from the spinning nozzle to the ejector. (3) A method of reducing the single hole discharge amount of the spinning nozzle. (4) A method of increasing the spinning temperature. Although the methods such as (1) and (2) are generally used when productivity is the main focus.

However, in the method (1), the filament group is disturbed when the filament is discharged from the opening device with the increase in the fluid flow rate, and the shape of the nonwoven web deposited on the net conveyor is reduced. Of the nonwoven web and deteriorates the homogeneity of the nonwoven web. In addition, an increase in the fluid flow rate causes an increase in running cost, which causes an increase in cost. On the other hand, the method (2) generally has a problem from the viewpoint of stable spinning, and improvement is required.

[0007]

DISCLOSURE OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and it is possible to stably spin and, moreover, efficiently thin and draw, and to open filament groups.
It is a technical object to provide a method for producing a long-fiber nonwoven fabric that enables the production of a highly homogeneous nonwoven fabric having a good dispersion state, and a method for producing a spunbond nonwoven fabric that is a long-fiber nonwoven fabric. By blending with the manufacturing method of melt-blown nonwoven fabric, the melt-spun continuous filament group is thinned and stretched by the frictional traction of the high-speed fluid to which vibration is applied, so that the thinning and stretching can be performed more efficiently than before, and Of nonwoven fabrics.

[0008]

Means for Solving the Problems The present invention has been obtained as a result of intensive studies to solve the above technical problems, and is as follows. 1. When a large number of continuous filaments melt-discharged from a spinning nozzle are thinned and drawn by the frictional traction force of a high-speed fluid to obtain a nonwoven fabric, the filament is pulled by a high-speed fluid having a vibration of 0.1 to 60 Hz, and the single-filament fineness is increased. Is 0.1 to 22d
A method for producing a long-fiber nonwoven fabric, comprising obtaining a long-fiber nonwoven fabric of tex. 2. 2. The long fiber according to claim 1, wherein the high-speed fluid is an air stream having a relative humidity of 80% or less and a temperature equal to or lower than a glass transition point (Tg) of the thermoplastic resin forming the long fiber. Manufacturing method of nonwoven fabric. 3. The method for producing a long-fiber nonwoven fabric according to any one of claims 1 to 2, wherein the irregularity of the long fiber is 1.1 or more.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, a method for producing a long-fiber nonwoven fabric according to the present invention will be described in detail. Melt spinning is carried out using a thermoplastic resin, which is preferably one thermoplastic resin.
It is extruded from multiple spinning nozzle holes arranged in rows or multiple rows. The thermoplastic resin to be melt-spun is not particularly limited as long as it has a fiber morphological property, such as polyethylene terephthalate, polybutylene terephthalate, polytrimethylene terephthalate, and a low-melting polyester copolymerized with isophthalic acid. Polyolefins such as polyesters, polypropylene, high-density polyethylene, medium-density polyethylene, low-density polyethylene, linear low-density polyethylene, di-terpolymers of propylene and other α-olefins, nylon 6, nylon 66 Polyamides such as these, or mixtures and copolymers thereof can be used, but polyesters are preferred from the viewpoint of the mechanical properties of the nonwoven fabric. Further, the present invention is not limited to a single-component long-fiber nonwoven fabric, and may be a multi-component type such as a sheath-core type, an eccentric sheath-core type, a side-by-side type, and a sea-island type.

In the present invention, an example of an apparatus specifically used is as shown in the schematic diagram of FIG.
A number of continuous melt-spun filament groups are shown in FIG.
By means shown in the flowcharts such as 3 and 4, the liquid is stretched and thinned by an ejector which is a high-speed fluid traction device capable of imparting vibration. However, the means for imparting vibration is not limited to such. For efficient thinning and stretching, 0.1 to 60H
It is preferable to use a high-speed fluid having a vibration of z. More preferably, it is a high-speed fluid having a vibration of 1 to 50 Hz. If the frequency is lower than 0.1 Hz, the fluctuation of the yarn becomes large, and the shape of the nonwoven web deposited on the net conveyor varies, which deteriorates the uniformity of the nonwoven web. When the frequency exceeds 60 Hz,
This is not preferable because the frictional traction force does not change from the case where no vibration is applied.

In the present invention, the flow rate of the fluid supplied for the purpose of imparting vibration is preferably 50% or less of the total fluid flow rate. More preferably, it is 20% or less. If it exceeds 50%, the pressure loss in the pipe increases, and the injection air pressure decreases. As a result, the frictional traction of the high-speed fluid decreases, which is not preferable. In addition, the fluctuation of the yarn becomes large, and the uniformity of the nonwoven web is deteriorated.

The long-fiber nonwoven fabric produced by the method of the present invention comprises filaments having a single-filament fineness of 0.1 to 22 dtex. If the single-fiber fineness is less than 0.1 dtex, yarn breakage during spinning increases, resulting in poor operability. On the other hand, if the single-fiber fineness exceeds 22 dtex, equipment for high discharge is required, which is not preferable. Particularly preferably, it was 0.1 to 17 dtex.

The high-speed fluid of the present invention has a relative humidity of 8
It is preferably 0% or less. If the relative humidity exceeds 80%, the adiabatic expansion of the fluid causes dew condensation water to adhere to the inside of the ejector, and the oligomer to adhere to that portion, causing thread breakage and the like.

The distance between the nozzle and the ejector during spinning is
It is preferably between 5 and 150 cm. More preferably, it is between 20 and 100 cm. This is because, when the fiber temperature is high, the thinning and drawing can be performed more efficiently by frictionally pulling with a high-speed fluid to which vibration is applied.
However, when the length is shorter than 5 cm, stable spinning becomes impossible, which is not preferable. On the other hand, when the length is longer than 150 cm, the influence of disturbance increases, and the spinning speed cannot be increased.

It is one of the preferable embodiments that the degree of irregularity of the long fiber is 1.1 or more. This is because when the irregularity of the long fiber is 1.1 or more, the contact area between the fiber and the fluid increases as compared with the case of a perfect circle (1.0 irregularity), and the frictional traction is efficiently performed. Therefore, the synergistic effect with the fluid vibration is considered to be large.

The intrinsic viscosity of the thermoplastic resin containing polyester as a main component is preferably 0.40 to 1.1 dl / g. More preferably, 0.50 to 1.0 dl / g
It is. If it is less than 0.40 dl / g, the mechanical properties of the filaments are reduced, and as a result, the mechanical properties of the nonwoven fabric are also reduced. In addition, spinnability also decreases. When it is larger than 1.1 dl / g, the vibration effect becomes small, which is not preferable.

As described above, a thinner filament can be obtained with the same high-speed air flow as the conventional one. Also,
When it is desired to obtain a filament having the same single-filament fineness as the conventional one, a smaller flow rate of high-speed air flow is required, so that the utility cost can be reduced by 30% or more.

[0018]

The present invention will be described in more detail with reference to the following Examples and Comparative Examples, but the present invention is not limited thereto. The evaluation method used in the examples and comparative examples of the present invention was based on the following method. (1) Intrinsic Viscosity of Polyester [dl / g] A 6: 4 weight mixed solution of phenol and tetrachloroethane was used as a solvent, and 0.1 g of a sample was dissolved in 25 ml of the solvent. (2) Single-fiber fineness of long fiber [dtex] The single-fiber fineness of the long-fiber nonwoven fabric is such that the nonwoven fabric is equally divided in the width direction into five equal parts, and five 1 cm square test pieces are sampled. The diameter of each fiber of each test piece was measured using an electron microscope, and the average value of the fiber diameters of a total of 100 fibers was determined. The fiber density was 1.38 g / cm ³ , and the single fiber fineness was calculated from the average value. did. (3) Deformity The non-deformability is determined by dividing the nonwoven web into five equally in the width direction and sampling 20 fibers from each web. Each fiber cross section is photographed with an optical microscope, and the diameters of a circumscribed circle and an inscribed circle in each fiber cross section are measured. The diameter ratio between the circumscribed circle and the inscribed circle was determined, and the average value of the diameter ratios of a total of 100 circles was determined as the irregularity. Degree of irregularity = Σ (diameter of circumscribed circle / diameter of inscribed circle) / 100 (4) Spreading state (visual appearance observation) The spreading state of the web was visually observed. (5) CV value [%] After removing the ears at both ends of the nonwoven fabric by 5 cm each, 5c in the width direction
m, cut to a length of 20 cm in the machine direction, the individual weight was measured, the average value and the standard deviation were obtained, and the CV value was calculated by the following equation. CV value [%] = standard deviation / average value × 100 (6) Tensile strength [N / 5 cm width] and elongation [%] Measured in accordance with JIS L 1906 using a constant speed elongation type tensile tester. . The average value of the maximum point load and the maximum point elongation of the test piece was obtained for each of MDTEX and CDTEX, and the tensile strength and elongation were calculated by the following equations. Tensile strength = (MDTEX average + CDTEX average) /
2 [N / 5cm width] Elongation = (MDTEX average + CDTEX average) / 2
[%]

Example 1 A long-fiber nonwoven fabric was manufactured using an apparatus as shown in FIG. 1 and an ejector which is a high-speed fluid traction apparatus capable of applying vibration as shown in a flowchart in FIG. A polyester having an intrinsic viscosity of 0.63 is melt-spun from a spinning nozzle at a spinning temperature of 290 ° C. and a single hole discharge rate of 1 g / min, and subjected to a vibration of 5 Hz using an ejector of the present invention having a rectangular slit at a temperature of 20 ° C. 5% relative humidity
The film was stretched by high-speed air flow. The size of the slit of this ejector was set to 4.5 mm × 300 mm, and the air blowing gap was set to 0.45 mm. Total air flow rate is 450 Nm ³ / h, it was injected airflow by setting as the flow rate of the vibration applying air of which is 90 Nm ³ / h. Thereafter, the fiber was spread by a known method, and collected and deposited on a moving net conveyor to obtain a nonwoven web. Then, using a thermocompression bonding device consisting of an embossing roll and a flat roll on the nonwoven web, the compression temperature was 250 ° C.
A thermocompression treatment was performed under the conditions of a linear pressure of 50 kg / cm and a compression area ratio of 12% to obtain a long-fiber nonwoven fabric having a basis weight of 30 g / m ² . The single-fiber fineness of the obtained long-fiber nonwoven fabric is 1.8 d.
tex. The results are shown in Table 1.

Example 2 A long-fiber nonwoven fabric having a basis weight of 30 g / m ² and a single-filament fineness of 2.1 dtex was obtained in the same manner as in Example 1 except that the frequency of the high-speed air flow was changed to 50 Hz. Table 1 shows the obtained results.

Example 3 The frequency of the high-speed air flow was 5 Hz, and the total air flow was 315 Nm.
³ / h: except that the injected high velocity air flow is set to (vibrating air flow 65Nm ³ / h) in a similar method as in Example 1, basis weight 30 g / m ^2, fineness 2.2dtex
Was obtained. Table 1 shows the obtained results.

Example 4 The frequency of the high-speed air flow was 5 Hz, and the total air flow rate was 450 Nm ^3.
/ H, except that the flow rate of the vibration-imparting air was set to 225 Nm ³ / h.
A long-fiber nonwoven fabric of 0 g / m ² and a single yarn fineness of 2.1 dtex was obtained. Table 1 shows the obtained results.

Example 5 Polyester having an intrinsic viscosity of 0.63 was melt-spun from a spinneret having a Y-shaped cross section at a spinning temperature of 290 ° C. and a single hole discharge rate of 1 g / min. Using a high-speed airflow at a temperature of 20 ° C. and a relative humidity of 5% to which vibration of 5 Hz was applied, thinning and stretching were performed. At this time, the total air flow rate was 450 Nm ³ / h (vibration imparting air flow rate: 90
Nm ³ / h). Thereafter, the fiber was opened by a known method and collected and deposited on a moving net conveyor to obtain a nonwoven web. The degree of irregularity of the obtained nonwoven web fiber was 2.2. Next, the nonwoven web was subjected to thermocompression bonding using a thermocompression bonding device including an embossing roll and a flat roll under the conditions of a compression temperature of 250 ° C., a linear pressure of 50 kg / cm, and a compression area ratio of 12%. , Weight is 30g
/ M ² long fiber nonwoven fabric was obtained. The single fiber fineness of the obtained long-fiber nonwoven fabric was 2.0 dtex. The results are shown in Table 1.

Comparative Example 1 The same manufacturing method as in Example 1 was conducted except that no vibration was applied to the high-speed airflow, and the basis weight was 30 g / m ² and the single-fiber fineness was 2.2.
A dtex long fiber nonwoven fabric was obtained. Table 1 shows the obtained results.

Comparative Example 2 A long-fiber nonwoven fabric having a basis weight of 30 g / m ² and a single-fiber fineness of 2.2 dtex was obtained in the same manner as in Example 1 except that the frequency of the high-speed airflow was changed to 65 Hz. Table 1 shows the obtained results.

Comparative Example 3 The same manufacturing method as in Example 4 except that vibration was not applied to the high-speed air flow, the basis weight was 30 g / m ² , and the single-fiber fineness was 2.3.
A dtex long fiber nonwoven fabric was obtained. The results obtained are shown in Tables 1 and 2.

[0027]

[Table 1]

[0028]

[Table 2]

As is clear from the results in Table 1, Example 1
The nonwoven webs obtained in Examples 1 and 2 had a single yarn fineness of Comparative Example 1.
Comparative Examples 1 and 2 showed good results although the spread state and CV value were somewhat inferior to Comparative Examples 1 and 2. In Example 3, although the flow rate of the high-speed airflow was smaller than in Comparative Examples 1 and 2, the single yarn fineness, tensile strength and elongation were at the same level. In Example 4, compared to Examples 1 and 2, the flow rate of the vibration-imparting air was larger, so
V value, tensile strength and elongation were slightly inferior.
In Example 5, even when the fiber had an irregular cross-section, the single-fiber fineness was smaller and the tensile strength was higher than in Comparative Example 3 of the conventional method. The result at the same level as that of No. 3 was shown. In Comparative Example 2,
Since the frequency of the high-speed airflow was too high, the frictional traction force was reduced, and there was little difference as compared with the case where no application was made.

[0030]

According to the production method of the present invention, a large number of continuous filament groups obtained by melt-spinning a thermoplastic resin are efficiently thinned and drawn by the frictional traction of a high-speed fluid to which vibration is applied. Can be. That is, the fineness of the single yarn can be reduced without increasing the air pressure supplied to the ejector. Further, when it is desired to obtain a filament having the same single-filament fineness as the conventional one, a smaller high-speed air flow is required, so that the utility cost can be reduced by 30% or more. Furthermore, the obtained nonwoven fabric has improved tensile strength as compared with the conventional nonwoven fabric.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of an apparatus for producing a long-fiber nonwoven fabric according to the present invention.

FIG. 2 is an example of a flowchart of a method for applying vibration to an ejector of the present invention.

FIG. 3 is an example of a flowchart of another method for applying vibration to the ejector of the present invention.

FIG. 4 is an example of a flowchart of another method for applying vibration to the ejector of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Extruder 2 ... Gear pump 3 ... Spinneret 4 ... Filament group 5 ... Ejector 6 ... Rotary valve 7 ... Dispersion plate 8 ... Net conveyor 9 ... Embossing roll 10 ... Nonwoven fabric 11 ... Winder

Claims (3)

[Claims] 1. A method in which a large number of continuous filaments melt-discharged from a spinning nozzle are drawn and thinned by frictional traction of a high-speed fluid to obtain a nonwoven fabric, and are drawn by a high-speed fluid to which a vibration of 0.1 to 60 Hz is applied. And the single yarn fineness is 0.1
A method for producing a long-fiber nonwoven fabric, characterized by obtaining a long-fiber nonwoven fabric of about 22 dtex. 2. The high-speed fluid according to claim 1, wherein the high-speed fluid is an air stream having a relative humidity of 80% or less and a temperature not higher than the glass transition point (Tg) of the thermoplastic resin forming the long fibers. 3. The method for producing a long-fiber nonwoven fabric according to item 1. 3. The method for producing a long-fiber nonwoven fabric according to claim 1, wherein the irregularity of the long fibers is 1.1 or more.