WO2006135147A1

WO2006135147A1 - Method of manufacturing a continuous filament by electrospinning and continuous filament manufactured thereby

Info

Publication number: WO2006135147A1
Application number: PCT/KR2006/000958
Authority: WO
Inventors: Hak-Yong Kim
Original assignee: Industrial Cooperation Foundation Chonbuk National University
Priority date: 2005-06-17
Filing date: 2006-03-16
Publication date: 2006-12-21
Also published as: KR100621428B1

Abstract

Disclosed are a method of manufacturing a continuous filament by electrospinning, and a continuous filament manufactured thereby. In the method of manufacturing a continuous filament by electrospinning, electrospun nano fibers are collected on a collector (3) in webs having a small width that are separate from each other by electrically spinning a polymer spinning dope in a spinning dope main tank (1) onto the collector (3), which is a cylindrical conductive material with a high voltage applied thereto and which rotates with one side of the lower end covered by a nozzle block (2), the nozzle block (2) having a high voltage applied thereto and one or more unit blocks combined in a C-shape, and arranged in a transverse or longitudinal direction, through nozzles (2a) in the unit blocks of the nozzle block (2), the unit blocks having segments repeatedly arranged at regular gaps, each of the segments having (1) to (5) nozzles (2a) arranged within a predetermined length, and then the nano fiber webs collected on the collector (3) are prepared in the form of a continuous filament (12) by a doubling machine (11) and wound on a winding machine (16) or put in a canvas.

Description

METHOD OF MANUFACTURING A CONTINUOUS FILAMENT BY ELECTROSPINNING AND CONTINUOUS FILAMENT MANUFACTURED THEREBY

TECHNICAL FIELD

The present invention relates to a method of manufacturing a continuous filament or yarn (hereinafter, commonly referred to as a

"filament") by electrospinning and a continuous filament manufactured thereby, and more particularly, to a method of manufacturing a continuous filament which is superior in physical properties and composed of a nano fiber by a continuous procedure by continuously producing a filament superior in drawing properties because of nano fibers well arranged in the filament axis direction, and then putting them in canvas through a traverse movement or continuously drying, drawing, and winding them.

In the present invention, the nano fiber refers to a fiber having a fiber diameter 1,000 nm or less, and more preferably, 500 nm or less.

A filament composed of a nano fiber can be utilized for artificial leather, filters, diapers, sanitary pads, sutures, antisetting agents, wiping cloths, artificial vessels, bone fixing devices and the like, and in particular, it is very useful for the production of the artificial leather.

BACKGROUND ART As conventional techniques for preparing an ultra fine fiber or

nano fiber suitable for the production of artificial leather, there are

known a sea-island type conjugated spinning method, a division type

conjugated spinning method, a blend spinning method and so on.

However, in case of the sea-island type conjugated spinning

method or the blend spinning method, one of two polymer components

comprising a fiber must be dissolved and removed for making the ultra

fine fiber. In order to produce artificial leather from the fiber prepared by

these methods, a complex process must be carried out, including melt

spinning, nano fiber production, non-woven fabric production, urethane

impregnation and single component dissolution. Nevertheless, it has

been impossible to produce a fiber with a diameter 1 ,000 nm or less by

the above two methods.

In case of the spit type conjugate spinning method, it has been

problematic in that since two polymer components (for example,

polyester and polyamide) with different dyeing properties co-exist in a

fiber, uneven dyeing occurs and an artificial leather production process is

complicated. In addition, it has been difficult to produce a fiber with a

diameter 2,000 nm or less by the above method. As another conventional technique for preparing a nano fiber, an

electrospinning method is suggested in U.S. Patent No. 4,323,525.

In the electrospinning method, a polymer spinning dope in a

spinning dope main tank is continuously and constantly fed into a plurality of nozzles, which has a high voltage applied, through a metering pump. Subsequently, the spinning dope fed to the nozzles is spun and collected through the nozzles on a collector of an endless belt type having a high voltage more than 5 kV, thereby producing a fiber web. The conventional electrospinning method can produce only a web or non-woven fabric composed of a nano fiber 1,000 nm or less. Thus, it is difficult to prepare a continuous filament using the conventional electrospinning method. Hence, to prepare a continuous filament, the produced nano fiber web has to be cut to a predetermined length to produce a staple fiber and this staple fiber has to be blown and undergone an additional spinning process, which makes the process complicated.

A spinning distance (distance between the nozzle and the collector) is so short in an electrospinning process that a method capable of drawing by applying a physical force is restrictive, and thus the mechanical properties are very low.

Meanwhile, as a method for arranging nano fibers in a fiber axis direction when preparing a filament composed of nano fibers, it has been already explained that fibers are arranged between conductive lines by placing the conductive lines on both sides of a nonconductive material such as quartz and then performing electrospinning thereon [Dan Li, Yuliang Wang, and Younan Xia, Advanced Materials VoI 16(4), pp361-366, 2004]. However, this method has a low possibility of industrialization, and any drawing force cannot be applied to this method.

Meanwhile, Korean Patent Application No. 2004-6402 discloses a process of preparing a filament composed of a nano fiber by preparing a ribbon-like nano fiber web by electrically spinning a nano fiber on a roller, twisting it while passing it through an air twisting machine, and then drawing it. However, this conventional process is problematic in that the strength of the prepared filament is low due to poor arrangement of nano fibers in the fiber axis direction. As seen from above, there is a problem that it is not possible to mass-produce a continuous filament composed of a nano fiber which is superior in drawing properties due to poor arrangement of nano fibers in the fiber axis direction by the conventional techniques known so far.

DETAILED DESCRIPTION OF THE INVENTION TECHNICAL PROBLEMS

The present invention is intended to mass-produce a continuous filament composed of a nano fiber which is superior in physical properties with a simple and continuous procedure by preparing an undrawn filament composed of a nano fiber which is superior in drawing properties using an electrospinning method, and then performing a drawing procedure. Additionally, the present invention is intended to provide a continuous filament of a nano fiber without any additional spinning process.

Additionally, the present invention is intended to provide a continuous filament of a nano fiber which is superior in physical properties and is suitable for various industrial materials, such as a filter, diaper, sanitary pad, artificial vessel and so on, as well as artificial leather.

TECHNICAL SOLUTIONS

To solve the above-described problems, there is provided a method of manufacturing a continuous filament by electrospinning method, wherein electrospun nano fibers are collected on a collector 3 in webs having a small width that are separate from each other by electrically spinning a polymer spinning dope in a spinning dope main tank 1 onto the collector 3, which is a cylindrical conductive material with a high voltage applied thereto and which rotates with one side of the lower end covered by a nozzle block 2, the nozzle block 2 having a high voltage applied thereto and one or more unit blocks combined in a C-shape, and arranged in a transverse or longitudinal direction, through nozzles 2a in the unit blocks of the nozzle block 2, the unit blocks having segments repeatedly arranged at regular gaps (s), each of the segments having 1 to 5 nozzles 2a arranged within a predetermined length (n), and then the nano fiber webs collected on the collector 3 are prepared in the form of a continuous filament 12 by a doubling machine 11 and wound on a winding machine 16 or put in a canvas.

Furthermore, the continuous filament of the present invention is prepared by the above method, has nano fibers of the continuous filament arranged at an angle of 10" or less in the axis direction of the continuous filament, and shows a necking stress or a partial/ complete stretched stress-strain curve on a stress-strain graph.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

First, in the present invention, as shown in FIG. l , electrospun nano fibers are collected on a collector 3 in webs having a small width that are separate from each other by electrically spinning a polymer spinning dope in a polymer spinning main tank 4 onto the collector 3, which is a cylindrical conductive material and which rotates with one side of the lower end covered by a nozzle block 2, the nozzle block 2 having a high voltage applied thereto and one or more unit blocks combined in a C-shape, and arranged in a transverse or longitudinal direction, through nozzles 2a in the unit blocks of the nozzle block 2, the unit blocks having segments repeatedly arranged at regular gaps (s), each of the segments having 1 to 5 nozzles 2a arranged within a predetermined length (n).

FIG. l is a schematic process diagram of the present invention for feeding a web separating mat 7 onto a collector 3.

As shown in FIG.2, the nozzle block 2 has a high voltage applied thereto, and has one or more unit blocks combined in a C-shape, and arranged in a transverse or longitudinal direction, the unit blocks having segments repeatedly arranged at regular gaps (s), each of the segments having 1 to 5 nozzles 2a arranged within a predetermined length (n) , FIG.2 is a perspective view of the C-shaped nozzle block 2 and the cylindrical collector 3 of FIG.1.

As shown in FIG.2, in the unit blocks of the C-shaped nozzle block

2, segments having 1 to 5 nozzles 2a arranged within a predetermined length (n) are repeatedly arranged at regular gaps (s). Due to this, the nano fibers electrically spun on the collector 3 are collected in webs having a small width (d) that are separate from each other.

A non-conductive plate is attached to the gaps (s) between the segments each having 1 to 5 nozzles arranged therein. The width (d) of one of the small width gaps collected on the collector 3 in a separate state is 1 to 60 mm, and more preferably, 5 to 40 mm.

If the width (d) is below than lmm, nano fibers dispersed are increased to deteriorate the spinning property. On the other hand, if the width (d) is above 60mm, the orientation of the nano fibers relative to the width direction of the webs becomes nonuniform, thereby making it difficult to prepare a filament.

The unit length (n) of the segments each having 1 to 5 nozzles 2a arranged therein is preferably 1 to 200 mm, and the gap (s) between the segments is preferably 1 to 100 mm.

Meanwhile, the collector 3 is a cylindrical conductive material, which rotates with one side of the lower end covered by the nozzle block, and has a high voltage applied thereto.

As above, in the present invention, at the time of electrospinning, the above-explained C-shaped nozzle block 2 and the rotating cylindrical collector 3 are used at the same time.

Next, the collected small width nano fiber webs are separated from the collector 3 in the form of a continuous filament 12 by a doubling machine 11 , and then they are wound on a winding machine 7 or put in a canvas.

The continuous filament 12 separated from the collector 3 may be dried or drawn before being wound around the winding machine. Meanwhile, in the present invention, as shown in FIG.4, it is also possible to prepare two or more types of a continuous filament simultaneously by using two or more C-shaped nozzle blocks 2 and two or more collectors 3, respectively.

In this case, the same polymer spinning dope may be fed into each of the two or more C-shaped nozzle blocks 2, and it is also possible to prepare filaments of different kinds by feeding different polymer spinning dopes.

FIG.4 is a schematic view of a process of preparing a continuous filament using two nozzle blocks and two collectors according to the

present invention. Reference numerals in the drawing are omitted.

The nozzles 2a arranged in the C-shaped nozzle blocks and the

collectors 3 are connected to a high voltage generator 1 and have a high

voltage applied thereto.

Moreover, the collector 3 rotates by a rotary motor.

The present invention can solve the limit of mass production,

which is a demerit of general electrospinning, because a large quantity of

nozzles can be arranged within a narrow space. Generally, in case of

electrospinning using one nozzle, the discharge amount is 0.6 to 2.0

mg/min, which is very small. Therefore, for mass production, it is very

important to increase production efficiency by arranging a large quantity

of nozzles within a narrow space. In this respect, the present invention

has a great advantage.

Meanwhile, the continuous filament prepared in the prior art electrospinning method is very weak in terms of physical properties.

Due to this, there are restrictions on the use of parts requiring

strong properties. The present invention can solve such a problem by

adjusting the rotational velocity of the collector 3. Specifically, since the orientation angle of nano fibers relative to a filament axis can be adjusted

by adjusting the rotational velocity of the collector 3, properties required

for various uses can be obtained. For instance, if electrospinning is

performed on the collector rotating at 5 m/sec, the orientation angle of nano fibers relative to a filament axis [traveling direction (machine direction) of the filament] is controlled to 3° or less, thereby greatly

improving the physical properties of the filament.

Moreover, in the present invention, it is possible to prepare an

isotropic composite filament by preparing two or more types of filaments having a different orientation angle of nano fibers relative to a filament axis, respectively, and then doubling them.

Within the C-shaped nozzle block 2, the nozzles 2a are arranged diagonally in a transverse or longitudinal direction, or linearly in a

transverse or longitudinal direction.

In the present invention, a yield per unit time can be increased by arranging a large quantity of nozzles within a narrow space. The

C-shaped nozzle block 2 may consists of one or two or more unit blocks, however, in a case where two or more unit blocks are combined, and

arranged in a transverse or longitudinal direction, it is convenient to replace the nozzles, it is easy to do cleaning if it is desired to change the

polymer to be used, and at the time of electrospinning, a tailor cone at the

tip of the nozzles can be formed stably, thereby improving the nano fiber forming property. Moreover, it is possible to prepare a hybrid filament by a method of feeding polymer spinning dopes different in kind or concentration to the unit blocks of the nozzle block 2, respectively.

It is better to place the C-shaped nozzle block 2 on a given frame so as to arbitrarily adjust the distance between the nozzles 2a and the collector 3.

Further, the distance (spinning distance) between the nozzle block 2 and the collector 3 can be adjusted by adjusting the diameter of the nozzle block 2 and of the collector 3.

The polymer spinning dope includes components selected from the group consisting of polyester resin, nylon resin, polysulfone resin, polylactic acid, chitosan, collagen, cellulose, fibrinogen, a copolymer thereof, sol-gel containing a metal component, a copolymer thereof and a mixture thereof.

The gist of the present invention is to easily control physical properties of the filament by freely adjusting the orientation angle of nano fibers relative to a filament axis direction according to the rotational linear velocity of the cylindrical collector 3 by using the nozzle block 2 and the cylindrical collector 3, the nozzle block 2 having one or more unit blocks combined in a C- shape, such that they are arranged in a transverse or longitudinal direction, the unit blocks having segments repeatedly arranged at regular gaps (s), each of the segments having 1 to 5 nozzles 2a arranged within a predetermined length (n), and the cylindrical collector 3 rotating with one side of the lower end covered by the nozzle block 2.

Generally, it is difficult for the filament prepared by electrospinning to have a system capable of applying a physical force during an electro spinning process. Because the distance between the

nozzles and the collector is 30cm or less, which is very slight, it is very difficult to apply a mechanical force to a narrow space.

In the present invention, nano fibers are arranged in a filament axis direction using a centrifugal force of the collector 3 which is rotating.

In the present invention, a partially or completely drawn filament is prepared by electrically spinning a polymer spinning dope onto a rotating collector 3 through a plurality of nozzles arranged in a C-shaped nozzle block 2 and arranging nano fibers side by side on the collector 3. As for a fiber prepared by electrospinning, it is a general phenomenon that crystallization is performed to a considerable extent according to the characteristics of the material. Additionally, the orientation degree of nano fibers relative to a filament axis is very low, thus the mechanical properties are very low and it is very difficult to increase the physical properties through a separate drawing process. The reason of which is because the drawing properties are substantially deteriorated due to formed crystalline and the mechanical properties are very low due to a low orientation degree relative to the filament axis direction. Therefore, it is possible to prepare a filament which suppresses the crystalline formation during an electrospinning process, and which is very superior in physical properties by arranging fibers electrospun at regular intervals in the filament axis direction. If the nano fibers formed in the electrospinning process are collected on the collector 3, which is a cylindrical rotating body, crystalline formation can be suppressed and

the nano fibers can be arranged in a row relative to the filament axis, thereby enabling it to prepare a filament which has superior physical properties. If the rotational linear velocity of the collector is too low, it is

difficult to suppress crystalline formation, and it is impossible to orient

electrospun nano fibers in a row relative to the filament axis. In the

present invention, depending on material, it is possible to obtain a filament having a low crystallinity or having partially/ completely drawn

nano fibers oriented well relative to the filament axis. Additionally, if drawing is required, if necessary, a filament

composed of nano fibers having superior mechanical properties can be prepared by performing drawing using a difference in the linear velocity of a roller.

Furthermore, in the present invention, there is included a method

for preparing a hybrid filament of a side-by-side type in which different polymers are arranged in a regular, repeating manner by supplying two or more types of polymer spinning dopes to respective nozzles within the

same nozzle block in an alternating manner and then electrospinning them. The nozzles 2 may be of a dual core-shell structure or a triple or more core- shell structure.

The number of the nozzles 2 is one or more, and more preferably,

100 or more. When electrically spinning a polymer spinning dope onto the cylindrical collector 3 which is rotating, it is more preferable to feed a nano fiber isolating solution to the collector 3.

The nano fiber isolating solution is one or two or more types of mixtures selected from water, an organic solvent, surfactant, and silicon oil.

Meanwhile, as shown in FIG. l, the present invention comprises, if necessary, feeding a nano fiber separating mat 7 onto a cylindrical collector 3 to collect the nano fibers on the nano fiber separating mat 7 when electrically spinning nano fibers.

In this case, it is preferred that the nano fiber separating mat 7 where the nano fibers are collected is cut to a width of 1 to 60 mm by a cutting machine 8.

The nano fiber separating mat 7 is discharged from its supply roller 5, passes through its feed rollers 6 and 9, and wound on its winding roller 10.

The nano fiber webs collected on the nano fiber separating mat 7 are separated from the nano fiber separating mat 7 before passing through the doubling machine 11 , and thereafter are made into a continuous filament 12 as they pass through the doubling machine 11.

The doubling machine 11 includes a typical air crosslinking device, a texturing device, etc.

The continuous filament of the present invention prepared by the above-described process according to the present invention has nano fibers of the continuous filament arranged at an angle of 10° or less in the

axis direction of the continuous filament, and shows a necking stress or a partial /complete stretched stress-strain curve on a stress-strain graph. The nano fibers of the filament of the present invention may have a hollow shape or have pores formed on the surfaces.

Particularly, the continuous filament of the present invention is very superior in physical properties because the nano fibers are arranged at an orientation angle of 10° or less in the filament axis direction.

ADVANTAGEOUS EFECTS

The present invention allows easy adjustment of the orientation angle of nano fibers relative to a filament axis direction, and offers a high yield per unit time because a large quantity of nozzles can be arranged even in a narrow space.

Accordingly, the present invention can mass produce a nano fiber filament having various physical properties in a continuous process.

Additionally, the present invention can easily produce a hybrid filament composed of nano fibers having a different type of polymer or a different diameter.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG.1 is a schematic view of a process of preparing a continuous filament according to the present invention;

FIG.2 is a schematic perspective view of a C-shaped nozzle block 2

and a cylindrical collector 3 of FIG.1 ;

FIG.3 is a schematic plane view of the C-shaped nozzle block 2 and

the cylindrical collector 3 of FIG.1; and

FIG.4 is a schematic view of a process of preparing a continuous

filament using two nozzle blocks and two collectors according to the

present invention.

* Explanation of Reference Numerals for the Major Parts in the Drawings

1 : high voltage generator 2: C-shaped nozzle block

2a: nozzle 3: cylindrical collector

4: polymer spinning dope main tank 5: web separating mat supply

roller

6: web separating mat feed roller 7: web separating mat

8: cutting machine 9: web separating mat feed roller

10: web separating mat winding roller 1 1 : doubling machine

12: continuous filament 13: first drawing roller

14: heater 15: second winding roller

16: continuous filament winding machine n: length of one segment having 1 to 5 nozzles arranged in unit blocks of

nozzle block 2 d: width of one of webs collected on collector separated from each other

s: gap between segments each having 1 to 5 nozzles in unit blocks A,B: type of polymer

BEST MODE FOR CARRYING OUT THE INVENTION

The present invention is now understood more concretely by comparison between examples of the present invention and comparative examples. However, the present invention is not limited to such examples.

Example 1

A polymer spinning dope was prepared by dissolving nylon 66 resin, which has a relative viscosity of 3.0 in a 96% sulfuric acid solution, in formic acid/acetic acid (volume ratio: 70:30) at a concentration of 15% by weight. The polymer spinning dope had a surface tension of 37 mN/m, a solution viscosity of 1, 100 centipoise at an ambient temperature and an electrical conductivity of 440 mS/m. Then, as shown in FIG. l, the prepared spinning dope was electrically spun onto a cylindrical (stainless steel) collector 3, which is a cylindrical conductive material with a high voltage applied thereto and which rotates at a rotational linear velocity of 5 m/min, with one side of the lower end covered by a nozzle block 2, the nozzle block 2 having a high voltage applied thereto and 370 unit blocks combined in a C-shape, and arranged in a transverse direction, through nozzles 2a in the unit blocks of the nozzle block 2, the unit blocks having segments arranged repeatedly 10 times at gaps (s) of 7cm, the segments each having three nozzles within a length (n) of 6.5 cm, such that the electrospun nano

fibers were collected on the collector 3 in webs having a width (d) of 12

mm, separated from each other.

The collector rotates by being connected to a rotary motor by a

connecting rod. The radius of the nozzle block 2 was 6 m, and the

transverse length thereof was 4.2 m. 30 nozzles were arranged as above

in one unit block of the nozzle block 2, thus the total number of nozzles in

the nozzle block 2 was 1 1, 100. The diameter of the nozzles was lmm,

the voltage thereof was 35 kV, and the spinning distance thereof was 12

cm.

Next, the nano fibers collected on the collector 3 were separated in

the form of a filament, and then wound on a winding machine 16, thereby

preparing 10 strands of continuous filaments by using a doubling

machine 1 1.

The thickness of the prepared continuous filament was 54 deniers,

the stress thereof was 176 MPa, the degree of elongation thereof was 26 %,

and the arrangement angle of nano fibers relative to a filament axis was

1.2^°.

INDUSTRIAL APPLICABILITY

The nano fiber filament prepared according to the present

invention is very superior in physical properties because nano fibers are

well arranged in a filament axis direction. Accordingly, the continuous filament prepared in the present invention is useful as materials for various industrial fields, such as an artificial dialyzing filter, artificial vessel, anti-adhesion agent, artificial bone, bottom decoration material, compound material and so on, as well as daily necessities, such as artificial leather, air cleaning filters, wiping cloths, golf gloves, wigs and so on.

Claims

WHAT IS CLAIMED IS:

1. A method of manufacturing a continuous filament by electrospinning, wherein electrospun nano fibers are collected on a collector 3 in webs having a small width that are separate from each other by electrically spinning a polymer spinning dope in a spinning dope main tank 1 onto the collector 3, which is a cylindrical conductive material with a high voltage applied thereto and which rotates with one side of the lower end covered by a nozzle block 2, the nozzle block 2 having a high voltage applied thereto and one or more unit blocks combined in a C-shape, and arranged in a transverse or longitudinal direction, through nozzles 2a in the unit blocks of the nozzle block 2, the unit blocks having segments repeatedly arranged at regular gaps (s), each of the segments having 1 to 5 nozzles 2a arranged within a predetermined length (n), and then the nano fiber webs collected on the collector 3 are prepared in the form of a continuous filament 12 by a doubling machine 11 and wound on a winding machine 16 or put in a canvas.

2. The method of claim 1, wherein the prepared filament 12 is dried and drawn before being wound.

3. The method of claim 1, wherein the width (d) of one of the webs collected on the collector 3, separated from each other, is 1 to 60 mm.

4. The method of claim 1, wherein the width (d) of one of the webs collected on the collector 3, separated from each other, is 5 to 40 mm.

5. The method of claim 1 , wherein a nano fiber separating mat 7 is fed onto a cylindrical collector 3 to collect the nano fibers on the nano fiber separating mat 7

6. The method of claim 5, wherein the nano fiber separating mat 7 where the nano fibers are collected is cut to width of 1 to 60 mm by a cutting machine 8.

7. The method of claim 1, wherein the length (n) of the segments each having 1 to 5 nozzles 2a arranged therein is 1 to 200 mm.

8. The method of claim 1, wherein the gap (s) between the segments each having 1 to 5 nozzles 2a arranged therein is 1 to 100 mm.

9. The method of claim 1, wherein the nozzles 2a in the nozzle block 2 are arranged diagonally or in a row in a transverse or longitudinal direction.

10. The method of claim 1 , wherein the nozzle block 2 consists of one or two or more unit blocks.

11. The method of claim 10, wherein two or more unit blocks

are assembled in a C- shaped frame.

12. The method of claim 1, wherein the nozzle block 2 is located

in the lower part of the collector 3.

13. The method of claim 1 , wherein the nozzles are of a dual

core-shell structure or a triple or more core-shell structure.

14. The method of claim 1 , wherein the polymer spinning dope

includes components selected from the group consisting of polyester

resin, nylon resin, polysulfone resin, polylactic acid, chitosan, collagen,

cellulose, fibrinogen, a copolymer thereof, sol-gel containing a metal

component, a copolymer thereof and a mixture thereof.

15. The method of claim 1, wherein a nano fiber separating

solution is fed onto the collector 3 which is a cylindrical conductive

material.

16. The method of claim 15, wherein the nano fiber separating solution is one or two or more types of mixtures selected from water, an organic solvent, surfactant, and silicon oil.

17. The method of claim 1 , wherein the number of the nozzles 2 is one or more.

18. The method of claim 1 , wherein the number of the nozzles 2 is 100 or more.

19. The method of claim 1, wherein a non-conductive plate is attached to the gaps (s) between the segments each having 1 to 5 nozzles arranged therein.

20. The method of claim 1, wherein two or more filaments are simultaneously prepared by using two or more nozzle blocks 2 and two or more collectors 3, respectively.

21. The method of claim 20, wherein two or more different types of polymer spinning dopes are fed to the two or more nozzle blocks 2, respectively.

22. The method of claim 1, wherein different types of polymer spinning dopes are fed to the unit blocks of the nozzle block 2, respectively.

23. A continuous filament manufactured by the method of any one of claims 1 to 22, which has nano fibers of the continuous filament arranged at an angle of 10° or less in the axis direction of the continuous filament, and shows a necking stress or a partial/ complete stretched stress-strain curve on a stress-strain graph.

24. The continuous filament of claim 23, wherein the nano fibers of the continuous filament have a hollow shape or have pores formed on the surfaces.

25. The continuous filament of claim 23, wherein the nano fibers of the filament are arranged at an angle of 5^° or less in the axis direction of the continuous filament.