KR100679073B1 - Method of manufacturing for nanofibers - Google Patents

Abstract

A nano fiber manufacturing method is provided to easily collect the nano fibers and to manufacture continuously the nano fibers through a simple process compared with the conventional technique. The high polymer spinning solution is electrically injected toward a base member(7) through a spinning nozzle(3) with an angle of 0.1-89 degrees against the horizontal surface of a collector so that a nano fiber(4) is manufactured. The spinning nozzle is located at nozzle plates(2) arrayed in parallel to the collector. The nano fiber manufactured by means of the base member is separated from the collector, dried and wound.

Description

Method of manufacturing nanofibers {Method of manufacturing for nanofibers}

1 and 2 is a process schematic diagram of the present invention employing a top-down electrospinning scheme.

3 and 4 are process schematic diagrams of the present invention employing a bottom-up electrospinning scheme.

5 is a schematic diagram showing that the nanofibers are formed by electrospinning.

* Code description of main parts of drawing

1: spinning liquid supply container 2: nozzle plate

3: nozzle 4: nanofiber

5: high voltage generator 6: collector

7 substrate 8 substrate feed roller

9, 10: feed roller 11: dryer

12: winding roller 13: laminate of nanofiber web and substrate

14: nanofiber web

θ ₁ : Angle between the collector and the ground plane

θ ₂ : Angle between the collector's horizontal plane and the nozzle

The present invention relates to a method for producing nanofibers using electrospinning, specifically, it is possible to prevent a droplet phenomenon during electrospinning, to easily concentrate nanofibers, and to continuously process nanofibers in a simple process. It relates to a method for producing nanofibers that can be produced.

In the present invention, the nanofiber means a fiber having a fiber diameter of 1,000 nm or less, more preferably 500 nm or less.

Mats composed of nanofibers can be widely used for general clothing, artificial leather, filters, diapers, sanitary napkins, sutures, anti-adhesion agents, wiping cloths, artificial blood vessels, bone fixing devices, and especially for artificial leather. Very useful for

Conventional techniques for producing ultrafine fibers or nanofibers suitable for the manufacture of artificial leather and the like are known as island-in-the-sea composite spinning, split composite spinning and blend spinning.

However, in the case of island-in-the-sea composite spinning or blend spinning, one of the two polymer components constituting the fibers must be eluted and removed for the finer fibers. In order to manufacture, there has been a problem of undergoing complex processes such as melt spinning, short fiber production, nonwoven fabric production, urethane impregnation, and one component elution. Nevertheless, it was not possible to produce fibers with a diameter of 1,000 nm or less by the conventional method.

On the other hand, in the split type composite spinning method, two polymer components having different dyeing characteristics (for example, polyester and polyamide) coexist in the fiber, so that a dyeing band appears, and the artificial leather manufacturing process has a complicated problem. In addition, it was difficult to produce fibers with a diameter of 2,000 nm or less by the above method.

As another conventional technique for manufacturing nanofibers, US 4,323,525 and the like have proposed an electrospinning method.

The electrospinning method continuously supplies the polymer spinning liquid in the spinning liquid main tank into a plurality of nozzles to which a high voltage is applied through a metering pump, and continuously supplies the spinning liquid supplied to the nozzle with a high voltage of 5 kV or more through the nozzle. The nanofiber web is manufactured by spinning and focusing on an endless belt type collector which is hanging and is parallel to the ground.

In the conventional electrospinning method, the polymer spinning liquid is electrospun directly through a nozzle on a collector parallel to the ground, so that the polymer spinning liquid falls into droplets during electrospinning (hereinafter referred to as "droplet phenomenon"). It is generated so that the nanofiber web is non-uniform, there was a problem that the concentration of nanofibers is difficult.

The present invention is to provide a method for continuously manufacturing nanofibers in a simple process by the electrospinning method. In addition, the present invention is to provide a nanofiber manufacturing method that is easy to focus the nanofibers.

To this end, the present invention electrospun the polymer spinning solution through the nozzle (3) toward the substrate (7) passing over the collector surface located outside the jet stream region of the polymer spinning solution formed during the electrospinning process to the nanofibers It provides a method of manufacturing and then separating and drying the nanofibers prepared using the substrate (7) from the collector after drying.

The present invention allows the collector to form a constant angle (θ ₁ ) with the horizontal plane of the ground so that the prevented nanofibers naturally fall by gravity.

The nozzle 3 arranged in the nozzle plate 2 forms a constant angle θ ₂ with the collector to prevent the drop phenomenon during electrospinning.

In the method of manufacturing a nanofiber according to the present invention for achieving the above object, the polymer spinning solution is placed on a nozzle plate (2) arranged under parallel and parallel to the collector 6 under high voltage to form an angle with the horizontal plane of the collector Through a spinning nozzle 3 having a (θ ₂ ) of 0.1 to 89 °, a high voltage is applied and forms a collector having an angle (θ ₁ ) of 0.1 to 89 ° with the horizontal plane of the ground and whose surface is located outside the jet stream of the polymer spinning liquid. (6) to form the nanofibers (4) by electrospinning toward the substrate (7) passing through the above, and then separated from the collector nanofibers (4) prepared using the substrate (7) and dried and It is characterized by winding up.

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

Typically, when the polymer spinning solution is electrospun through the nozzle 3, the electrospun polymer spinning solution as shown in FIG. 5 forms a Taylor cone, and the Taylor cone turns into a jet stream by electric force and is included in the jet stream. In the incomplete region in which the polymer chain and the solvent are separated, the polymer chain is separated into a predetermined size to form nanofibers. 5 is a schematic diagram showing that nanofibers are formed by electrospinning.

Hereinafter, the present invention will be described in detail with reference to FIGS. 1 to 4.

1 and 2 are process schematic diagrams of the present invention employing a top-down electrospinning scheme, and FIGS. 3 and 4 are process schematic diagrams of the present invention employing a bottom-up electrospinning scheme. (+) Or (-) charge is applied to the polymer spinning liquid supply container 1 through the high voltage generator 5, and the nozzle 3 in the nozzle plate 2 connected to the polymer spinning liquid supply container 1 is removed. The polymer spinning liquid is discharged through a certain amount. The spinning liquid discharged through the nozzle 3 once forms a Taylor cone, which is then turned into a jet stream by electric force and then forms nanofibers. The nanofibers 4 formed as above are integrated onto the substrate 7 passing over the surface of the collector 6 under high voltage. The collector 6 is charged with-or + from the high voltage generator 5.

Contact with the substrate 7 passing over the collector just prior to jet stream formation makes nanofibers impossible. Therefore, the distance from the nozzle tip to the collector solution surface (hereinafter referred to as "radiation distance") can be very important.

Jet stream lengths vary for all polymer types used, but are typically less than 5 cm. Highly conductive polymers generally have a longer jet stream.

Therefore, the radiation distance cannot be measured uniformly but must be longer than the length of the jet stream.

The collector 6 is preferably an angle (θ ₁₎ of 0.1~60 ° decided at an angle (θ ₁₎ of the horizontal plane of the ground surface and 0.1~89 °, more preferably.

As described above, when the collector 6 forms an angle greater than 0.1 ° with the horizontal plane of the ground, the aggregated nanofibers fall downward due to gravity, thereby greatly improving the focusability.

On the other hand, the angle θ ₂ formed between the horizontal plane of the nozzle and the collector 6 is 0.1 to 89 °, more preferably 0.1 to 60 °, and the droplet falling in the form of droplets when the spinning liquid is electrospun. It is preferable to prevent the phenomenon.

In the present invention, after separating the nanofiber web formed on the surface of the collector solution by using the substrate (7) passing through the collector 6 from the surface of the collector 6 forming a constant angle (θ ₁ ) with the horizontal plane of the ground Dry and wind up. The substrate 7 may use a film or a mesh. The nanofibers separated in this way are dried while passing through the dryer 11 and wound around the winder 12.

The substrate 7 may be wound from the winding roller 12 together with the nanofiber web after being fed from the substrate feeding roller 8 as shown in FIGS. 1 and 3, as shown in FIGS. 2 and 4. As described above, it may be repeatedly passed on the surface of the collector 6 in an endless form. 2 and 4, the substrate and the nanofiber web are separated before passing through the dryer 11, and only the nanofiber web is wound around the winding roller 12.

The polymers usable in the present invention include (i) natural polymers such as cellulose and chitosan, copolymers or mixtures thereof, (ii) thermoplastic resins such as polyester, nylon and fluororesin, copolymers or mixtures thereof, and (iii) ) Thermosetting resins such as melamine and epoxy, copolymers or mixtures thereof, and sol-gels containing inorganic substances such as aluminum and titanium.

As described above, the manufacturing method of the present invention can improve the convergence of the nanofibers by integrating the electrospun nanofibers on the substrate 7 passing through the surface of the inclined collector.

In addition, by controlling the angle (θ ₁ ) formed by the horizontal plane of the collector and the ground and the angle (θ ₂ ) formed by the nozzle of the collector horizontal plane to prevent the droplet phenomenon.

The nanofibers are particularly useful for producing yarns due to their excellent focusing properties, and can be used for the production of nonwoven fabrics.

Through the following examples will be described in detail the present invention.

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

Example  One

A poly (ε-caprolactone) polymer (manufactured by Aldrich, USA) having a number average molecular weight of 80,000 was dissolved in a tetrahydrofuran / N, N-dimethylformamide (volume ratio: 60/40) mixed solvent at a concentration of 9% by weight. A polymer spinning solution was prepared. The surface tension of the polymer spinning solution was 33 mN / m, the solution viscosity was 120 centipoise at room temperature, the electrical conductivity was 0.4 mS / m. The angle (θ ₁ ) of the polymer spinning solution prepared as described above with the horizontal plane of the ground (i) through the spinning nozzle 3 under high voltage as shown in FIG. 1 is 45 °, (ii) high voltage is applied, (Iii) The nanofibers were formed by electrospinning toward the polyethylene film (substrate) whose surface passes over the collector 6 located outside the jet stream 4 of the polymer spinning solution. After the nanofibers are prepared and formed, the nanofibers are separated from the collector by using a polyethylene film (substrate) passing through the collector surface, and then dried in a dryer 11 and wound up. It wound up by (12).

At this time, the diameter of the nozzle used was 0.8mm and the nozzle array was used as a unit block in which 50 nozzles were arranged at 110cm in the width direction between nozzles at 2cm intervals. The angle between the nozzle and the collector (θ ₂ ) is 45 °, and the nozzle plate composed of 10 unit blocks is used, and the nozzles arranged on the 10 unit blocks are diagonally disposed in the direction of movement of the porous film (machine direction). Evenly arranged. The electrospinning distance was 5.5 cm, and 10 unit blocks were reciprocated at a speed of 1 cm / min in the width direction in order to secure thickness uniformity of the nanofiber web. In addition, in the dryer 11, it dried using the air of 35 degreeC, and the winding speed of the winding roller 12 was 50 cm / min.

The fiber diameter of the prepared nanofibers was 615 nm, the physical properties of the prepared nanofiber web was measured by the ASTM D 638 method, the strength was 2.2MPa, the elongation was 530%.

The present invention can manufacture the nanofibers in a simple process according to the electrospinning method, it is possible to improve the convergence of the nanofibers.

Claims (6)

The polymer spinning liquid is placed on the nozzle plate 2 under high voltage and arranged in parallel with the collector 6, and through the spinning nozzle 3 having an angle θ ₂ of 0.1 to 89 ° with the horizontal plane of the collector, The nanofibers are subjected to a high voltage and are electrospun toward the substrate 7, which is at an angle (θ ₁ ) of 0.1 to 89 ° with the horizontal plane of the ground and whose surface passes over the collector 6 located outside the jet stream of polymer spinning liquid. Forming (4), and then separating and drying the nanofibers (4) prepared using the substrate (7) from the collector, characterized in that the manufacturing method of nanofibers. The method of manufacturing a nanofiber according to claim 1, wherein the angle (θ ₁ ) between the collector (6) and the horizontal plane of the ground is 0.1 to 60 °. The method of manufacturing a nanofiber according to claim 1, wherein the angle (θ ₂ ) formed by the horizontal plane of the nozzle (3) and the collector (6) is 0.1 to 60 °. The method of claim 1, wherein the polymer constituting the polymer spinning solution is one or a mixture thereof selected from the group consisting of natural polymer resins, thermoplastic resins, thermosetting resins, and sol-gels containing inorganic substances. Method for producing nanofibers. The method of producing a nanofiber according to claim 1, wherein the nanofiber and the substrate (7) are wound together. The method for producing nanofibers according to claim 1, wherein the nanofibers are separated from the substrate (7), and then only the nanofibers are wound.

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