KR101406117B1 - Method of manufacturing nanofiber via centrifugal forces and air current - Google Patents

Abstract

The present invention relates to a method for manufacturing nanofibers, comprising the steps of: supplying a spinning dope composed of one kind selected from polymer solution and polymer melt into a spinning tube that (i) has one kind of shape selected from a spherical shape, a conic shape, combined two conic shapes and combined four conic shapes, (ii) is connected to a motor by a connection bar, and (iii) has, on the surface of an inner part, one kind of formation selected from a groove and a protrusion; spinning the spinning dope, which has been supplied to the spinning tube, in the shape of nanofibers via centrifugal force by rotating the spinning tube with the rotation of a motor at 3,000 rpm or more; and accumulating the nanofibers spun from the spinning tube on a collector placed at the upper part of the spinning tube via centrifugal force generated by the rotation of the spinning tube and an air current generated by the rotation of a blade for air generation by rotating the blade for air generation, which is installed on one selected from the outer surface of the spinning tube and the connection bar, at 3,000 rpm or more together with the spinning tube. The present invention can manufacture nanofibers at high productivity (discharge amount) from not only polymer solution but also polymer melt as the viscosity of the polymer melt can be decreased without decomposing polymer via high shearing force using only a pure air current without static electricity. In addition, the present invention can evade operation danger as high voltage does not need to be applied to the collector etc.

Description

TECHNICAL FIELD The present invention relates to a method for manufacturing nanofibers using centrifugal force and air flow,

The present invention relates to a method of manufacturing nanofibers using centrifugal force and air flow, and more particularly, to a method of manufacturing nanofibers using centrifugal force and air flow, To a method of producing fibers.

The spinning tube for manufacturing the nanofiber of the present invention replaces a conventional nozzle used as a mechanism for discharging a spinning solution.

Conventional nanofibers have been produced primarily by electrospinning.

As the electrospinning apparatus used for manufacturing the conventional nanofibers, a nozzle (nozzle) fixed by a mechanism for ejecting a spinning solution has been mainly adopted as disclosed in Korean Patent No. 10-0420460.

However, since the conventional electrospinning devices are electrospinning (discharging) the spinning liquid through the fixed nozzle, electrospinning is performed depending on only the electrostatic force, and the discharge amount per nozzle unit per unit time is extremely low to 0.01 g level, And problems such as nozzle replacement and cleaning are complicated and cumbersome.

In general, the production of nanofibers through electrospinning is 0.1 to 1 g per hour, and the solution discharge rate is very low, ranging from 1.0 to 5.0 mL per hour [D. H. H. Renecker et al., Nanptechnology 2006, Vo 17, 1123].

In another conventional electrospinning apparatus, a polyvinylpyrrolidone solution is supplied while a high voltage is applied to a conical container rotated at 50 rpm, and an electrospinning apparatus which is electrospinned by using both electrostatic force and centrifugal force at the same time is referred to as Jinyuan Zhou et al. (Small, 2010 Vol 6, 1612-1616) published in Small in 2010.

However, although the conventional electrospinning apparatus can improve the production amount per unit time in the form of no nozzle by utilizing the centrifugal force and the electrostatic force, it is difficult to continuously produce the continuous solution by supplying the spinning liquid into the conical container, (Hereinafter referred to as "drop generation phenomenon") occurs when the collector is located and the spinning liquid falls into the solution state instead of the fiber form.

Also, a system for a system in which a large number of nozzles are arranged on a nozzle plate and electrospinning is already well known [H. Y. Kim, WO2005073441, WO2007035011].

Disadvantages of the conventional electrospinning devices are that it is dangerous to apply a high voltage to the electrospinning device, and the production amount of nanofibers per unit hole is very low, and there is a problem that the nozzles are cleaned by using nozzles, Although the solution can be electrospun, there is a problem that the polymer melt obtained by melting the polymer can not be electrospun.

This is because the conventional electrospinning apparatuses can not impart the high shear force required to lower the viscosity of the polymer melt to the electrospun polymer melt without decreasing the molecular weight of the polymer melt.

As a result, it has been required to develop a spinning device capable of producing a nanofiber using a polymer melt as well as a polymer solution.

In another conventional spinning device for nanofiber, a spinning solution (a polymethylmethacrylate solution dissolved in chlorobenzene) injected into the above-mentioned cylinder by using a cylinder rotating at a high speed of 3,000 rpm or more is spin- (Nano Letters, 2008, Vol 8, No. 4, 1187-1191) published by K. Kern et al. In Nano Letters.

However, in the conventional spinning device for nanofibers, it is difficult to separate a polymer solution and a solvent from each other in a cylinder, so that the ability to form nanofibers is deteriorated, and it is difficult to continuously supply the spinning solution in a cylinder.

In addition, since the centrifugal force acts in the circumferential direction of the cylindrical body, the radiated nanofibers fly in the circumferential direction and it is difficult to collect the collected nanofibers on the collector located on the upper side of the cylindrical body. Therefore, in the above-mentioned conventional method, the upward-direction spinning is difficult, and the spinning solution is supplied from the upper part of the cylinder to the lower part so that only the top-down spinning in which the nanofibers radiated on the chelator positioned at the lower end of the cylinder are accumulated, There is a problem that the droplet phenomenon that falls to the surface of the substrate can not be effectively prevented.

It is an object of the present invention to provide a polymer melt and a polymer melt which can be spin-coated without a high voltage by centrifugal force and air flow, The productivity is greatly improved, the trouble of nozzle replacement and cleaning can be solved, and a drop occurrence phenomenon can be effectively prevented.

In order to achieve the above object, the present invention provides a method of manufacturing a connector, comprising the steps of: (i) forming a cylindrical shape, a conical shape, a shape in which two conical shapes are combined with each other, and a shape in which four conical shapes are combined with each other, (Iii) supplying a spinning dope composed of one kind selected from a polymer solution and a polymer melt into a spinning tube in which a shape selected from a groove or a projection is formed on an inner surface of the spinning dope; and A step of spinning the spinning tube by a motor rotation at 3,000 rpm or more to spin the spinning dope supplied to the spinning tube by centrifugal force into a nanofiber form; The nanofibers emitted from the spinning tube are rotated with the spinning tube by rotating at 3,000 rpm or more with the spinning tube It provides a method for producing a nanofiber via a turn; by the air flow generated by the centrifugal force generated with the rotation of the air occurs for the wings to be integrated on a step of the collector which is located above the spinning tube.

Since the viscosity of the polymer melt can be lowered without decomposition of the polymer with high shear force using only pure centrifugal force and air flow without electrostatic force, the nanofiber can be produced from the polymer melt as well as the polymer melt with high productivity (discharge amount) .

Further, since the conventional spinning nozzle is not used in the present invention, troublesome operations such as nozzle replacement and nozzle cleaning can be omitted, and a high voltage is not applied to the collector, so that the risk of work can be avoided.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a schematic view of a process of the present invention. Fig.
Figures 3 to 8 are perspective views of a spinning tube used in the present invention.
Figs. 9 to 12 are schematic plan views showing a state in which the spinning tube used in the present invention is opened in the longitudinal direction and opened. Fig.
Figures 13 (a) - 13 (d) are schematic perspective views of an article formed on the inner surface of the radiation tube.
14 is a scanning electron micrograph of the nanofiber prepared in Example 1 of the present invention.

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

The present invention relates to an electric motor comprising (i) one type selected from the group consisting of a cylindrical shape, a conical shape, a combination of two conical shapes and a combination of four conical shapes, (ii) Iii) supplying a spinning dope composed of one kind selected from a polymer solution and a polymer melt into a spinning tube in which one kind of shape selected from a groove or a projection is formed on an inner surface;

Rotating the spinning tube by a motor rotation at 3,000 rpm or more to spin the spinning dope supplied to the spinning tube by centrifugal force into nanofiber form; And

The air generating vanes provided on one of the outer surface of the radiation tube and the connecting rod are rotated together with the radiation tube at 3,000 rpm or more to rotate the nanofibers radiated from the radiation tube by the centrifugal force generated by the spinning tube and the rotation of the air- And accumulating on the collector located above the radiation tube by the generated air flow.

Specifically, the present invention first supplies a radial dope as a polymer solution or a polymer melt into the radiation tube T shown in Figs. 3 to 13 (d), as shown in Figs.

FIGS. 1 to 2 are schematic views of the process of the present invention, FIGS. 3 to 8 are schematic perspective views of the radiation tube, FIGS. 9 to 12 are schematic plan views showing a state in which the radiation tube is opened in the longitudinal direction, 13 (a) to 13 (d) are schematic perspective views of an article formed on the inner surface of the radiation tube.

3 to 6, the radial tube T has a cylindrical shape, a conical shape, a combination of two conical shapes or a combination of four conical shapes, As shown in Fig. 12, grooves or protrusions are formed.

3 to 4, the shape of the radiation tube may be a plurality of spiral curves extending along the inner surface of the cylindrical or conical radiation tube T, As shown in FIG. 6, the shapes may be dispersed on the inner surface of the cylindrical or conical radiation tube T in a state that they are separated from each other. Alternatively, two or four cones may be formed as shown in FIGS. Or may be a structure in which the shape is formed on the inner surface of the radiation tube T, which is a combined shape.

In order to efficiently integrate the nanofibers formed by efficiently separating the nanofibers formed in spinning and the solvents in the spinning solution onto the collector located on the upper side, It is more preferable that it is a structure formed so as to form a curve.

As shown in Figs. 13 (a) to 13 (d), the shape formed on the inner surface of the radiation tube T is a polygonal projection, a semicircular projection, a polygonal groove or a semicircular projection.

As an example of the polygonal projection, a triangular projection, a square projection, or the like may be used. As the example of the polygonal groove, a triangular groove, a square groove, or the like may be used.

The grooves or protrusions formed on the inner surface of the radiation tube T facilitate the separation of the solvent in the polymer solution and the spinning solution in the spinning tube when the nanofibers are prepared with the polymer solution, (i) inducing the binding of the polymer chains, (Ii) facilitating the directional control of the formed nanofibers, that is, moving the formed nanofibers to the upper direction instead of the horizontal direction, and thereby forming the formed nanofibers in the upper part of the radiation tube And effectively collects them on the collector.

Specific embodiments of the radiation tube will now be described with reference to the drawings.

The radial tube T according to the first embodiment has a cylindrical shape as shown in Fig. 3, and the inner surface Ti of the radial tube has a rectangular groove (shape) as shown in Fig. 13 (a) Is formed so as to form a plurality of helical curves (S) continuous in the same direction along the inner surface (Ti) of the radiation tube. A schematic plan view showing a state in which the radiation tube T of the first embodiment is cut open is shown in Fig.

The radial tube T according to the second embodiment has a cylindrical shape as shown in Fig. 3, and the inner surface Ti of the radial tube has a semicircular groove (shape) as shown in Fig. 13 (b) Is formed so as to form a plurality of helical curved lines S continuous only in the same direction along the inner surface Ti of the radiation tube.

A schematic plan view showing the unfolded state of the radiation tube T of the second embodiment is shown in Fig.

The radial tube T according to the third embodiment has a cylindrical shape as shown in Fig. 3, and the inner surface Ti of the radial tube has a semicircular protrusion (shape) as shown in Fig. 13 (c) Is formed so as to form a plurality of helical curved lines S continuous only in the same direction along the inner surface Ti of the radiation tube.

A schematic plan view showing the unfolded state of the radiation tube T of the third embodiment is shown in Fig.

The radial tube T according to the fourth embodiment has a cylindrical shape as shown in Fig. 3, and the inner surface Ti of the radial tube has a triangular projection (shape) as shown in Fig. 13 (d) Is formed so as to form a plurality of helical curved lines S continuous only in the same direction along the inner surface Ti of the radiation tube.

A schematic plan view showing a state in which the radiation tube T of the fourth embodiment is cut open is shown in Fig.

The radial tube T according to the fifth embodiment has a cylindrical shape as shown in Fig. 4, and the inner surface Ti of the radial tube has a rectangular groove (shape) as shown in Fig. 13 (a) Are formed so as to form a plurality of helical curved lines (S) that are continuous in both directions along the inner surface (Ti) of the radiation tube and cross each other.

A schematic plan view showing a state in which the radiation tube T of the fifth embodiment is cut open is shown in Fig.

The radial tube T according to the sixth embodiment has a cylindrical shape as shown in Fig. 5, and the inner surface Ti of the radial tube has a semicircular protrusion (shape) as shown in Fig. 13 (c) Are formed separately from each other on the inner surface (Ti) of the radiation tube.

11 is a schematic plan view showing a state in which the radiation tube T of the sixth embodiment is cut open.

The radial tube T according to the seventh embodiment has a conical shape as shown in Fig. 6, and a semicircular groove (shape) as shown in Fig. 13 (b) is formed on the inner surface Ti of the radiant tube And is dispersed in the inner surface Ti of the radiation tube in a state of being separated from each other.

A schematic plan view showing a state in which the radiation tube T of the seventh embodiment is cut open is shown in Fig.

Next, the spinning tube T is rotated by 3,000 rpm or more, preferably 5,000 rpm or more by rotating the motor 5, and the spinning dope is radiated in a nanofiber form by centrifugal force.

Next, the air generating vanes provided on one of the outer surface of the radiation tube and the connecting rod are rotated together with the radiation tube at 3,000 rpm or more, so that the nanofibers radiated from the radiation tube are rotated by centrifugal force generated by the spinning tube, The nanofibers are integrated on the collector located above the radiation tube by the air flow generated by the rotation of the wings to produce nanofibers.

The air generating blade has a structure for generating an air flow toward the upper side of the radiating tube by rotation, and the number of the blades is preferably one or more.

It is preferable that the collector 9 is disposed at a position higher than the radiation tube T to prevent the droplet phenomenon, that is, the phenomenon that the solvent falls on the collector 9 together with the nanofibers.

The present invention is characterized in that the grooves or projections formed on the inner surface of the spinning tube effectively separate the solvent and the polymer in the spinning tube so that the spinning tube is excellent in fiber forming ability and the centrifugal force generated by the rotation of the spinning tube, To the upper portion of the spinning tube, so that only the nanofibers formed are collected on the collector except for the solvent contained in the spinning solution, thereby effectively preventing the droplet phenomenon.

In addition, according to the present invention, by generating an air stream flowing in an upward direction of the radiation tube by the rotation of the air generating blades, the radiated nanofibers can be collected more efficiently on the collector located in the upper portion of the radiation tube .

Hereinafter, the present invention will be described in more detail with reference to examples and comparative examples.

However, the scope of protection of the present invention is not limited by the following examples.

Example  One

Polyacrylonitrile (product of Aldrich) having a weight average molecular weight (Mw) of 150,000 was dissolved in dimethylformamide as a solvent to prepare a spinning dope having a solid content of 9 wt% and a viscosity of 477 centipoise.

Next, the spinning dope produced as shown in FIG. 1 is supplied at a supply rate of 5 cc / min by a metering pump, (i) two cones are coupled together as shown in FIG. 7, (ii) A rectangular groove as shown in FIG. 13 (a) is fed to the lower end of the radiation tube T formed so as to form four continuous spiral curves along the inner surface, and then the radiation tube is rotated at 10,000 rpm, ) Was spun in the form of nanofibers.

At this time, the upper inner diameter of the conical radiation tube was 42 mm, the lower inner diameter of the conical radiation tube was 30 mm, the pitch interval between the helical curves was 7 mm, and the depth H of the rectangular groove was 2 mm , And the width W of the rectangular groove was 4 mm.

Next, as described above, the radial dope is radiated through the spinning tube T rotating, and at the same time, is provided on the connecting rod 4 connecting the spinning tube T and the motor 5, The air generating vanes 3 having three wings for causing air flow are rotated together with the radiation tube T at 10,000 rpm to generate centrifugal force generated by rotation of the spinning tube of the nanofibers radiated from the radiation tube, The nanofibers were integrated on the collector 9 located above the radiation tube by the air flow generated by the rotation of the wings 3 to produce nanofibers.

The scanning electron micrograph of the manufactured nanofiber was as shown in FIG. 14, and the average diameter of the nanofiber was 740 nm.

T: Radiation tube S: Spiral curve
Ti: inner surface of the radiating tube H: groove depth of the shape in the shape of a quadrangular groove
A: A part of the shape of the spiral curve
W: groove width of a shape in the form of a quadrangular groove
P: Projection G: Home
R: groove depth of a semi-circular groove shaped object
R ': height of projection of semi-circular projection
1: nanofiber 3: air generating blade
4: Connecting rod connecting radiating tube and motor
5: Rotary motor
6: Radiation Dope Supply Tank 7: Quantity Feed Pump
9: collector 10: nanofiber mat
11: Nano fiber mat rolling roll

Claims (5)

(I) one type selected from the group consisting of a cylindrical shape, a conical shape, a combination of two conical shapes and a combination of four conical shapes, (ii) connected to the motor by a connecting rod, (iii) Supplying a spinning dope composed of one kind selected from a polymer solution and a polymer melt into a radiation tube in which one kind of shape selected from a groove or a projection is formed on a surface;
Rotating the spinning tube by a motor rotation at 3,000 rpm or more to spin the spinning dope supplied to the spinning tube by centrifugal force into nanofiber form; And
The air generating vanes provided on one of the outer surface of the radiation tube and the connecting rod are rotated together with the radiation tube at 3,000 rpm or more to rotate the nanofibers radiated from the radiation tube by the centrifugal force generated by the spinning tube and the rotation of the air- And collecting on the collector located above the radiation tube by the generated air flow. The method of manufacturing nanofibers using centrifugal force and air flow. The method of manufacturing a nanofiber according to claim 1, wherein the air generating blade has a structure for generating an air flow in an upper direction of the radiating tube by rotation. 2. The method of claim 1, wherein the shape is formed to form a plurality of continuous spiral curves along the inner surface of the radiation tube. The method according to claim 1, wherein the shape of the nanofibers is dispersed on the inner surface of the radiation tube in a state where the shapes are separated from each other. The method of manufacturing a nanofiber according to claim 1, wherein the shape formed on the inner surface of the radiation tube is one of a polygonal protrusion, a semicircular protrusion, a polygonal groove, and a semicircular groove.

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