WO2006006746A1

WO2006006746A1 - Polymer particles, and a method for manufacturing the same

Info

Publication number: WO2006006746A1
Application number: PCT/KR2004/001697
Authority: WO
Inventors: Hak-Yong Kim; Jong-Cheol Park
Original assignee: Hak-Yong Kim; Jong-Cheol Park
Priority date: 2004-07-09
Filing date: 2004-07-09
Publication date: 2006-01-19

Abstract

Conventional polymer particles used as various industrial materials, such as filters, gene carriers, drug carriers, catalysts, reinforcing materials of a composite material, additives of cosmetics and the like, have a small surface area, require complicated production processes and facilities, and are difficult to mass produce. In the present invention, polymer particles are mass-produced using a simple process and facilities by electrically spinning a polymer spinning solution in a spinning solution main tank 1 on a fluid present on the surface of a conductor collector 11 with a high voltage applied thereto via nozzles with a high voltage applied thereto, and then separating and drying the formed polymer particles.

Description

POLYMER PARTICLES, AND A METHOD FOR MANUFACTURING

THE SAME

TECHNICAL FIELD The present invention relates to polymer particles and a method for manufacturing the same. More particularly, the present invention relates to a method for manufacturing polymer particles using electric spinning and polymer particles manufactured by the same.

In the present invention, polymer particles are made of a polymer and include polymer particles without hollows or fine holes formed thereon, polymer particles with hollows formed thereon, polymer particles with a plurality of fine holes formed thereon, and polymer particles with both of hollows and a plurality of fine holes formed thereon.

Polymer particles are utilized as various industrial materials, such as filters, gene carriers, drug carriers, catalysts, reinforcing materials of composites, additives of cosmetics and the like.

BACKGROUND ART

In general, a great number of methods for manufacturing spherical polymer particles by water-oil emulsion methods and water-oil-water methods are known. As one of those methods, U.S. Patent

No. 5,945,126 discloses a method in which a dispersion phase is prepared by dissolving a poly^L-lactide-co-glycolide) (PLGA) copolymer in methylene chloride and dissolving leuprolide acetate as an agent in methanol and mixing them, a continuous phase is prepared by dissolving polyvinyl alcohol) in distilled water and then the continuous phase and the dispersion phase are mixed to manufacture spherical particles.

Also, U.S. Patent No. 6,048,551 discloses a method in which spheres are formed via a water-oil-emulsion method by dissolving poly(L-lactide-co-glycolide) in methylene chloride and placing a gene transfer vector therein, namely, an adenovirus, then the gene transfer vector is encapsulated using a solution comprising water as a solvent, such as polyvinyl alcohol, and then spheres including the gene transfer vector are prepared by removing the polyvinyl alcohol by isopropyl alcohol and drying. As seen from above, a method for manufacturing spherical particles by an emulsion method has been generally employed as a conventional method for manufacturing polymer particles.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view of a process for manufacturing polymer particles by a horizontal electric spinning method according to the present invention;

FIG. 2 is a schematic view of a process for manufacturing polymer particles by a downward electric spinning method according to the present invention; and FIG. 3 is a schematic view of a process for manufacturing polymer particles by an upward electric spinning method according to the present invention.

* Explanation of Reference Numerals for Main Parts of the Drawings 1 : spinning solution main tank

2: spinning solution dropper (continuous flow prevention device)

3: subsidiary tank

4: nozzle block

5: overflow solution recovery tank 6: nozzle (spinneret)

7: spun polymer particles

8: fluid tank supplying fluid to collector surface

9: fluid- supply quantitative pump

10a: fluid-supply nozzle tube for horizontal electric spinning 10b: fluid-supply nozzle tube for upward electric spinning

11 : conductor collector

12: high voltage generator

13: focusing device of spun polymer particle and fluid

14a: film supply roller used for upward electric spinning 14b: film take-up roller used for upward electric spinning

15: film used for upward electric spinning

16: polymer particle recovery knife used for upward electric spinning DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS (TECHNICAL PROBLEM)

The present invention provides a method in which polymer particles can be made by a process which is simpler than emulsion methods, namely, by an electric spinning method through which mass production is possible.

Polymer particles are very useful in various fields including filters, clothing, genes, chemical carriers, cosmetics, dyes, catalysts, etc. because they have a large surface area for filtering. An object of the present invention is to manufacture polymer particles in large quantity by a simple process and utilizing simplistic facilities. (TECHNICAL SOLUTION)

To achieve the aforementioned object, there is provided a method for manufacturing polymer particles, wherein polymer particles are prepared by electrically spinning a polymer spinning solution in a spinning solution main tank 1 on a fluid existing on the surface of a conductor collector 11 with a high voltage applied thereto via nozzles 6 with a high voltage applied thereto, and then separating and drying the prepared polymer particles.

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

First, the electric spinning method employed in the present invention may be a downward electric spinning method, as shown in FIG. 2, in which nozzles 6 are located on an upper part of a conductor collector 11, may be an upward electric spinning method, as shown in FIG. 3, in which nozzles 6 are located at a lower part of a conductor collector 11 , or may be a horizontal electric spinning method, as shown in FIG. 1, in which nozzles 6 and a conductor collector 11 are horizontal or are maintained at an angle close to horizontal.

FIG. 1 is a schematic view of a process for manufacturing polymer particles via a horizontal electric spinning method according to the present invention. FIG. 2 is a schematic view of a process for manufacturing polymer particles by a downward electric spinning method according to the present invention. FIG. 3 is a schematic view of a process for manufacturing polymer particles by an upward electric spinning method according to the present invention. Among these, the horizontal electric spinning method of FIG. 1 will be described concretely.

In the horizontal electric spinning method, as shown in FIG. 1 , a solution for electric spinning is supplied through a spinning solution main tank 1 and maintained at a constant level in a subsidiary tank 3, and the electric spinning solution is supplied to a nozzle block 4 through a spinning solution dropper 2 for preventing solution flow. Solution overflowing the nozzle block 4 is recovered to the main tank 1 through an overflow solution recovery tank 5 and is subsequently reused. Meanwhile, in order to uniformly flow a fluid down the surface of a conductor collector 11, a fluid in a fluid tank 8 is supplied to a

fluid-supply nozzle tube 10a, in which nozzles for uniformly supplying a

fluid are arranged on the surface of the collector, through a fluid-supply quantitative pump 9. Continually, the spinning solution supplied to the nozzle block 4 is electrically spun through the nozzle 6 on the fluid flowing on the surface of the conductor collector 11 with a high voltage

applied thereto.

As above, by performing electric spinning while applying a high

voltage between the conductor collector 11 and the nozzle 6 via a high voltage generator 12, polymer particles 7 are formed on the fluid.

Next, a flowing fluid and the formed polymer particles 7 are focused onto a focusing device 13, the fluid is removed and only pure

polymer particles are collected. When removing the fluid from the mixture

of the fluid and the polymer particles, a filter, a centrifugal separator, a dehydrator or the like is used.

In case of the horizontal electric spinning as set forth, the fluid is

present over the surface of the conductor collector 11 , being flowed down

a slit or shower type nozzle. Next, the downward electric spinning of FIG. 2 will be described

concretely.

In the downward electric spinning method, as shown in FIG. 2, a solution for electric spinning is supplied through a spinning solution main tank 1 and maintained at a constant level in a subsidiary tank 3, and the electric spinning solution is supplied to a nozzle block 4 through a spinning solution dropper 2 for preventing solution flow. Solution overflowing the nozzle block 4 is recovered to the main tank 1 through an overflow solution recovery tank 5 and is subsequently reused.

Meanwhile, a fluid in a fluid tank 8 is supplied to a focusing device 13 through a fluid-supply quantitative pump 9 so that a conductor collector 11 may be submerged in the fluid, thus trapping the fluid on the conductor collector. Continually, the spinning solution supplied to the nozzle block 4 is electrically spun through the nozzle 6 on the surface of the fluid spaced a constant distance from the conductor collector 11 with a high voltage applied thereto, thereby forming polymer particles 7.

Preferably, the distance between the fluid surface and the top surface of the conductor collector 11 is 0.01 to 200mm, in view of production efficiency.

Next, the fluid and polymer particles focused onto the focusing device 13 are separated to collect only pure polymer particles. When separating the fluid and the polymer particles, a filter, a centrifugal separator, a dehydrator or the like is used.

In case of the downward spinning as set forth, the fluid is present on the surface of the conductor collector 11 , with the conductor collector 11 being submerged in the fluid. Next, the upward electric spinning of FIG. 3 will be described concretely.

In the downward electric spinning method, as shown in FIG. 3, a solution for electric spinning is supplied through a spinning solution main tank 1 and maintained at a constant level in a subsidiary tank 3, and the electric spinning solution is supplied to a nozzle block 4 through a spinning solution dropper 2 for preventing solution flow. Solution overflowing the nozzle block 4 is recovered to the main tank 1 through an overflow solution recovery tank 5 and is subsequently reused. Meanwhile, a film 15 is continuously supplied to the surface of a conductor collector 11 by a film supply roller 14a, a fluid in a fluid tank 8 is supplied to a fluid supply nozzle 10b through a fluid-supply quantitative pump 9, and thereafter a proper amount of the fluid is applied to the film by spraying or the like. At this point, the supply of the fluid is controlled so that the fluid applied to the film may be adhered

thereto.

Continually, the spinning solution supplied to the nozzle block 4 is electrically spun through the nozzle 6 on the surface of the fluid applied to the film passing over the conductor collector 11 with a high voltage applied thereto, thereby forming polymer particles 7.

Next, the polymer particles 7 formed on the film 15 are separated and recovered to a focusing device 13 via a recovery knife 16, and then the film 15 is wound around a film take-up roller 14b. Next, the fluid and polymer particles focused onto the focusing device 13 are separated to collect only pure polymer particles. When separating the fluid and the polymer particles, a filter, a centrifugal separator, a dehydrator or the like is used. As to the upward spinning as set forth herein, the fluid is present on the surface of the conductor collector 11 , with the fluid being applied to the film passing over the conductor collector 11.

In the event that the fluid present on the conductor collector 11 is heated, pores and/ or hollows can be formed on the polymer particles more efficiently.

Especially, in the downward electric spinning, when supplying a preheated fluid, that is, when supplying a preheated fluid to the focusing device 13, pores and hollows can be formed more efficiently on the formed polymer particles. As the fluid, water, an organic solvent, a surfactant and a polymer solution containing a polymer are used.

Suitable organic solvents include methanol, ethanol, propanols, toluene, methylene chloride, benzene or acetic acid.

Suitable surfactants include cationic surfactants, anionic surfactants, zwitterionic surfactants and non-ionic surfactant.

Such a surfactant can be variously selected and used according to the charge distribution of the polymer. For example, in the event that polymer particles to be prepared are ketonic acids, which are cationic polymers, when spinning on the surface of a fluid containing an anionic surfactant, polymer particles having pores and/ or hollows can be prepared more efficiently.

In the present invention, nano-fibers can be manufactured simply by controlling the concentration of a polymer solution, and filaments or the like can be easily manufactured simply by a focusing device, for example, by using an air focusing device or removing the nano-fibers from the fluid surface and passing them through a focusing roller.

As the polymer spinning solution of the present invention, thermoplastic resin, a natural polymer, a copolymer thereof, a mixture thereof, or a sol-gel containing a metal composition may be used.

Concretely, the polymer spinning solution of the present invention may include polyester resins, nylon resins, polysulfone resins, polylactic acids, ketonic acids, collagen, cellulose, fibrinogen, copolymera thereof, a mixture thereof or a sol-gel containing a metal composition.

In the present invention, in the event that polymer spinning solutions of two or more kinds are spun via two or more nozzle blocks or they are spun via one nozzle block in which nozzles for spinning different polymer spinning solutions are combined, polymer particles composed of a mixture of two or more polymer compositions can be manufactured more easily.

In other words, polymer particles composed of a mixture of two or more polymer compositions can be manufactured by electrically spinning polymer spinning solutions of two or more kinds on the same fluid through respective nozzles in different nozzle blocks via two ore more nozzle blocks, or electrically spinning polymer particles composed of a mixture of two or more polymer compositions on the same fluid through respective nozzles arranged in the same nozzle block by using one nozzle block, in which nozzles for spinning polymer spinning solutions of two or more different polymers are combined therein.

In the present invention, regarding the principle of manufacturing porous or hollow polymer particles, as a fluid enters into the polymer particles during the process in which polymer particles electrically spun on the fluid present on the conductor collector 11 are coagulated and the fluid escapes during the coagulation and drying process, pores and/ or hollows are formed on the polymer particles. Especially, when a flowing fluid is heated, such a phenomenon can be controlled more freely.

ADVANTAGEOUS EFFECT

In the present invention, polymer particles optionally having hollows and/ or pores can be manufactured using a simple process and simple facilities. Polymer particles made in the present invention are useful as materials for various fields including various industrial filters, drug carriers, gene carriers, various composition filling materials, secondary cell electrode materials, carriers for hydrogen storage, catalysts, cosmetic additives and the like. BEST MODE FOR EMBODYING THE INVENTION

Hereinafter, the present invention will be described in detail with respect to embodiments. But, the present invention is not restricted to the following embodiments.

MODE FOR EMBODYING THE INVENTION Embodiment 1

A polymer solution (spinning solution) was prepared by dissolving 2% by weight of nylon 66 manufactured by BASF having a relative viscosity of 2.7 in formic acid. The prepared spinning solution had a viscosity of 45 centipoises (cPs), which was measured using a rheometer DV-III (Brookfield Co., USA), and an electric conductivity of 0.286 mS/m, which was measured using a conductivity meter CM-40G (TOA electronics Co., Japan). Electric spinning was performed by a horizontal electric spinning method as shown in FIG. 1 using such a solution (spinning solution). Concretely, the polymer solution (spinning solution) was supplied to a main tank 1 , the supplied solution (spinning solution) passed through a spinning solution dropper (continuous flow prevention device) 2 so as to prevent a continuous flow of the polymer solution, a subsidiary tank 3 for preventing excessive flow of a spinning solution was installed on a spinning plate nozzle block 4 so as to control supply of the spinning solution using an atmospheric pressure, and a level around nozzles arranged for maintaining a smooth spinning efficiency was maintained at a predetermined position. An overflow generated from the

nozzle block to control the predetermined position of the solution naturally flowed down the nozzle block. The recovered solution was

recovered to the spinning solution main tank 1 through the solution

recovery tank 5 and was reused. 100 nozzles were arranged in each spinning plate nozzle block, and 10 of such nozzle blocks 4 were installed, such that a total of 1000 nozzles were provided. The diameter of the nozzles was 0.6mm, The solution (spinning solution) discharged through

the nozzles 6 was spun at 30 kV, supplied by a high voltage generator 12, to the surface of the collector 11. The distance between the nozzles and the collector where water flows was 12cm. During the electric spinning,

water uniformly flows from a separate water tank 8, via a fluid- supply

quantitative pump 9, over the surface of the collector by a nozzle tube 10a where nozzles having a slit width of 1.0mm are arranged. Then,

particles 7 of nylon 66 were prepared on the water surface due to such high voltage, and these particles 7 were dropped along with naturally flowing water, water and the particles were focused on a focusing device 13, collected by a filter, and dried, thereby obtaining particles. The average size of the spherical particles of nylon 66 thus

prepared was 425 nm.

Embodiment 2 A polymer solution (spinning solution) having a concentration of 1% by weight was prepared by dissolving poly (L-lactide) (PLLA) manufactured by Boerhringer Ingelheim having a molecular weight of 650,000 in methylene chloride. The prepared spinning solution had a viscosity of 20 centipoises (cPs), which was measured using a rheometer DV-III (Brookfield Co., USA), and an electric conductivity of 0.01 mS/m, which was measured by a conductivity meter CM-40G (TOA electronics Co., Japan). Electric spinning was performed by a downward electric spinning method as shown in FIG. 2 using such a solution (spinning solution). Concretely, the polymer solution (spinning solution) was supplied to a main tank 1 , the supplied solution (spinning solution) was passed through a spinning solution dropper (continuous flow prevention device) 2 so as to prevent a continuous flow of the polymer solution, a subsidiary tank 3 for controlling a flow of an excessive spinning solution due to a rapid supply was installed on a spinning plate nozzle block 4 so as to control the supply of the spinning solution using an atmospheric pressure, and a level around nozzles arranged for maintaining a smooth spinning efficiency was maintained at a predetermined position. An overflow generated from the nozzle block to control the predetermined position of the solution naturally flowed down the nozzle block. The recovered solution was recovered to the spinning solution main tank 1 through the solution recovery tank 5 and was reused. 60 nozzles were arranged in each spinning plate nozzle block, and 5 of such nozzle blocks 4 were installed, such that a total of 300 nozzles were installed. The diameter of the nozzles was 0.8mm. The solution (spinning solution) discharged through the nozzles 6 was spun at 30 kV, supplied from a high voltage generator 12, to the surface of the collector 11. The distance between the nozzles and the collector where water flows was 15cm. During the electric spinning, a predetermined amount of water was supplied to the surface of the collector through a fluid-supply quantitative pump 9 from a separate water tank 8, and electric spinning was performed on the surface. The collector was installed at a distance of 5cm from the water surface. Then, particles 7 of poly(L-lactide) (PLLA) were prepared on the water surface by a high voltage, and these particles 7 fell into the water. When the fallen particles were removed from the water, collected by a filter and dried, thus obtaining particles of poly (L-lactide) (PLLA). The average diameter of the obtained poly(L-lactide) particles was 31 μm.

Claims

What is claimed is:

1. A method for manufacturing polymer particles, wherein polymer particles are manufactured by electrically spinning a polymer spinning solution in a spinning solution main tank 1 on a fluid present on the surface of a conductor collector 11 with a high voltage applied thereto via nozzles 6 with a high voltage applied thereto, and then separated and dried.

2. The method of claim 1, wherein the polymer particles are one selected from the group consisting of a hollow type having a hollow portion, a porous type having a plurality of fine pores and a hollow-porous type having both hollow portions and a plurality of fine pores.

3. The method of claim 1, wherein the fluid is one selected

from the group consisting of water, an organic solvent, a surfactant and a

polymer solution containing a polymer.

4. The method of claim 1, wherein the fluid exists, being flowed down the surface of the conductor collector 11.

5. The method of claim 1, wherein the fluid exits, being adhered to the surface of the conductor collector 1 1.

6. The method of claim 1, wherein the fluid is present on the

surface of the conductor collector 1 1 , with the conductor collector 11

being fully submerged in the fluid.

7. The method of claim 1, wherein the electric spinning

method is one selected from the group consisting of a downward electric

spinning method, in which nozzles 6 are located on an upper part of a

conductor collector 1 1, an upward electric spinning method, in which

nozzles 6 are located at a lower part of a conductor collector 1 1 , and a

horizontal electric spinning method, in which nozzles 6 and a conductor

collector 11 are horizontal or are maintained at an angle close to

horizontal.

8. The method of claim 7, wherein, as to the downward

electric spinning method, the conductor collector 1 1 is submerged in the

fluid so that the distance between the fluid surface and the top surface of

the collector 1 1 is 0.01 to 200 mm.

9. The method of claim 7, wherein, as to the upward electric

spinning method, a film 15 with the fluid applied thereto is supplied to

the surface of the conductor collector 1 1.

10. The method of claim 7, wherein, as to the horizontal electric spinning, the fluid is flowed down the surface of the conductor collector

11.

11. The method of claim 10, wherein the fluid is flowed down

the surface of the conductor collector 11 via a slit or shower type nozzle.

12. The method of claim 1, wherein the fluid present on the conductor collector 1 1 is heated.

13. The method of claim 1, wherein the average diameter of the particles is less than lmm.

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

solution is composed of polyester resin, nylon resin, polysulfone resin, polylactic acid, ketonic acid, collagen, cellulose, fibrinogen, a copolymer thereof, a mixture thereof or a sol-gel containing a metal composition.

15. The method of claim 3, wherein the organic solvent includes methanol, ethanol, propanols, toluene, methylene chloride, benzene or acetic acid.

16. The method of claim 3, wherein the surfactant includes a cationic surfactant, anionic surfactant, zwitterionic surfactant and non-ionic surfactant.

17. The method of claim 1, wherein polymer spinning solutions of two or more kinds are electrically spun on the same fluid present on the surface of the conductor collector 11 through different nozzles 6 arranged on one nozzle block.

18. The method of claim 1, wherein polymer spinning solutions of two or more kinds are electrically spun on the same fluid present on the surface of the conductor collector 11 through respective nozzles 6 arranged on two or more respective nozzle blocks.

19. Polymer particles made by the method of any one of claims

1 to 18.