Process of preparing continuous filament composed of nanofibers
Conventional electrospinning was problematic in that it is incapable of making a continuous filament (yarn) by a simple and continuous process. To solve the above problem, there is provided a method for making a continuous filament consisting of nanofibers according to the present invention, wherein a polymer spinning liquid is electrostatically spun to a collector 7 through nozzles 5 to obtain a nanofiber web 17 a of ribbon form, then the nanofiber web 17 a is passed through an air twister 18 and twisted to obtain a nanofiber filament 17 b of a continuous filament form, and then the nanofiber filament 17 b is drawn.
1 . A process of preparing a continuous filament composed of nanofibers, wherein a polymer spinning liquid is electrospun to a collector 7 through nozzles 5 to obtain a nanofiber web 17 a of ribbon form, then the nanofiber web 17 a is passed through an air twister 18 and twisted to obtain a nanofiber filament 17 b of a continuous filament form, and then the nanofiber filament 17 b is drawn.
2 . The process of claim 1 , wherein the nanofiber web 17 a of ribbon form is obtained by electrospinning in a manner that the width of the nanofiber web 17 a is the same as the overall width of the collector 7 and then cutting the nanofiber web by a web cutter 16 .
3 . The process of claim 2 , wherein the web cutter 16 consists of a rotary blade 16 a and a motor 16 b rotating the rotary blade.
4 . The process of claim 1 , wherein the nanofiber web 17 a of ribbon form is obtained by electrospinning in narrow sections in a manner the width of the nanofiber web 17 a is the same as the width of one nozzle block 4 .
5 . The process of claim 4 , wherein a collector 7 with barriers 7 b installed thereto at the same distance as the width of one nozzle block 4 is used in electrospinning.
6 . The process of claim 1 , wherein the air twister 18 is provided with a passage of the nanofiber web 17 a and an air outlet formed at the center along the longitudinal direction and an air inlet formed in a direction perpendicular or inclined to the air outlet.
7 . The process of claim 1 , wherein the electrospinning type is upward electrospinning type, downward electrospinning type or horizontal electrospinning type.
8 . The process of claim 1 , wherein a nanofiber web separating film or a nonwoven fabric 24 is continuously fed onto the surface of the collector 7 where nanofibers are electrostatically spun.
9 . The process of claim 1 , wherein a nanofiber web separating solution 27 is continuously or discontinuously coated or sprayed onto the collector 7 where nanofibers are electrostatically spun.
10 . The process of claim 9 , wherein the nanofiber web separating solution 27 is water, a cationic surfactant, an anionic surfactant, an amphoteric (cationic-anionic) surfactant, or a neutral surfactant.
11 . The process of claim 9 , wherein the web separating solution 27 is methanol, ethanol, toluene or methylene chloride.
12 . The process of claim 1 , wherein the nanofiber filament 17 b is drawn between two rollers by using a gap in rotation linear velocity between the rollers.
13 . The process of claim 1 , wherein more than two kinds of nanofiber webs of ribbon form obtained by electrostatically spinning more than two kinds of spinning liquids are passed through one air twister 18 .
14 . The process of claim 1 , wherein the drawn nanofiber filament 17 b is heat treated.