U.S. patent application number 11/722873 was filed with the patent office on 2008-05-01 for conjugate electrospinning devices, conjugate nonwoven and filament comprising nanofibers prepared by using the same.
Invention is credited to Hak-Yong Kim, Jong-Cheol Park.
Application Number | 20080102145 11/722873 |
Document ID | / |
Family ID | 37889036 |
Filed Date | 2008-05-01 |
United States Patent
Application |
20080102145 |
Kind Code |
A1 |
Kim; Hak-Yong ; et
al. |
May 1, 2008 |
Conjugate Electrospinning Devices, Conjugate Nonwoven and Filament
Comprising Nanofibers Prepared by Using the Same
Abstract
Discloses are a conjugate electrospinning devices for preparing
fibers (nanofibers) having a nano-level thickness, and nanofibers
prepared using the same. The conjugate electrospinning devices
comprises: spinning dope main tanks (1); metering pumps (2); a
nozzle block (4); nozzles (5) aligned on the nozzle block; a
collector (7) for collecting fibers spun from the nozzle block; and
a voltage generator (9) for applying a voltage to the nozzle block
and the collector (7), wherein [I] nozzles for spinning two or more
different kinds of spinning dope are aligned on a nozzle block (4)
regularly or in random order in repetitive units at the same ratio
or in different ratios, aligned in random order at a predetermined
ratio, or aligned thereon in random order at a predetermined ratio,
or aligned thereon repetitively; [II] the number of the spinning
dope main tanks (1) is two or more; and [III] a spinning dope drop
device (3) is arranged between the spinning dope main tanks (1) and
the nozzle block (4). Since two or more different kinds of spinning
dopes are combined and electrospun, and thus the physical
properties (features) of a non-woven fabric and a filament can be
easily managed by a simple process. Nanofibers and their non-woven
fabrics can be mass produced because the fiber formation effects
are maximized.
Inventors: |
Kim; Hak-Yong;
(Chonrabuk-do, KR) ; Park; Jong-Cheol; (Seoul,
KR) |
Correspondence
Address: |
BIRCH STEWART KOLASCH & BIRCH
PO BOX 747
FALLS CHURCH
VA
22040-0747
US
|
Family ID: |
37889036 |
Appl. No.: |
11/722873 |
Filed: |
September 26, 2005 |
PCT Filed: |
September 26, 2005 |
PCT NO: |
PCT/KR05/03183 |
371 Date: |
June 26, 2007 |
Current U.S.
Class: |
425/72.2 |
Current CPC
Class: |
D01F 8/12 20130101; D01D
5/30 20130101; D01D 5/0069 20130101 |
Class at
Publication: |
425/72.2 |
International
Class: |
D01D 5/00 20060101
D01D005/00 |
Claims
1. A conjugate electrospinning devices, comprising: spinning dope
main tanks 1; metering pumps 2; a nozzle block 4; nozzles 5 aligned
on the nozzle block; a collector 7 for collecting fibers spun from
the nozzle block; and a voltage generator 9 for applying a voltage
to the nozzle block and the collector 7, wherein [I] nozzles for
spinning two or more different kinds of spinning dope are aligned
on a nozzle block 4 regularly or in random order in repetitive
units at the same ratio or in different ratios, aligned in random
order at a predetermined ratio, or aligned thereon in random order
at a predetermined ratio, or aligned thereon repetitively; [II] the
number of the spinning dope main tanks 1 is two or more; and [III]
a spinning dope drop device 3 is arranged between the spinning dope
main tanks 1 and the nozzle block 4.
2. The devices of claim 1, wherein the nozzles for spinning two or
more different kinds of polymer spinning dope are aligned on the
nozzle block 4 alternately in a row in either transverse,
longitudinal or diagonal direction.
3. The devices of claim 1, wherein the outlets of the nozzles 5
aligned on the nozzle block 4 are formed in an upward direction,
and the collector 7 is positioned at an upper part of the nozzle
block 4.
4. The devices of claim 1, wherein the entire part of the nozzle
block 4 reciprocates to the left and right.
5. The devices of claim 1, wherein a heater is installed in the
collector 7.
6. The devices of claim 1, wherein an agitator 11c is installed in
the nozzle block 4.
7. The devices of claim 1, wherein a spinning dope discharger 12
for forcibly feeding the spinning dope not spun in the nozzle
regions to the spinning dope main tank 1 is formed on the upper
part of the nozzle block 4.
8. The devices of claim 1, wherein the collector 7 is fixed or
continuously rotates.
9. The devices of claim 1, wherein the outlets of the nozzles 5 are
formed in the shape of one or more flared tubes having an angle
.theta. of 90 to 175.degree..
10. The devices of claim 1, wherein the nozzle block 4 includes:
[I] a nozzle plate 4f on which nozzles 5 for spinning different
spinning dopes are aligned regularly or in random order in
repetitive units in the same ratio or in different ratios and two
or more spinning dope supply plates 4h and 4h' positioned at the
lower end of the nozzle plate and for supplying the spinning dope
to the nozzles; [II] overflow removal nozzles 4a surrounding the
nozzles 5, an overflow temporary storage plate 4g connected to the
overflow removal nozzles and positioned at the right upper end of
the nozzle plate and an overflow removal nozzle supporting plate 4e
positioned at the right upper end of the overflow temporary storage
plate and supporting the overflow removal nozzles; [III] air supply
nozzles 4b surrounding the nozzles 5 and the overflow removal
nozzles 4a, an air supply nozzle supporting plate 4c positioned at
the top end of the nozzle block and supporting the air supply
nozzles and an air storage plate 4d positioned at the right lower
end of the air supply nozzle supporting plate and supplying air to
the air supply nozzles; [IV] a conductor plate 4i having pins
aligned in the same way as the nozzles and positioned at the right
lower end of the nozzle plate; and [V] a heating plate 4j
positioned at the right lower end of the spinning dope supply
plate.
11. The devices of claim 10, wherein the nozzles for spinning two
or more different kinds of polymer spinning dope are aligned on the
nozzle block 4 alternately in a row in either transverse,
longitudinal or diagonal direction.
12. A conjugate nanofiber non-woven fabric prepared using the
conjugate electrospinning devices of claim 1.
13. A discontinuous conjugate nanofiber filament prepared using the
conjugate electrospinning devices of claim 1.
Description
TECHNICAL FIELD
[0001] The present invention relates to an conjugate
electrospinning devices which can mass-produce two or more kinds of
fibers having a nano level thickness (hereinafter, "nanofibers") at
a time by simultaneously electrospinning two or more different
kinds of polymer spinning dope through nozzles aligned on one
nozzle block.
[0002] Moreover, the present invention relates to a conjugate
non-woven fabric (herainfter, "conjugate nanofiber non-woven
fabric) which is prepared by the aforementioned conjugate
electrospinning devices and has two or more kinds of nanofibers
mixed with each other.
[0003] Moreover, the present invention relates to a continuous
filament (herainfter, "conjugate nanofiber filament) which is
prepared by the aforementioned conjugate electrospinning devices
and has two or more kinds of nanofibers mixed with each other.
[0004] Products, such as non-woven fabrics, membranes, braids,
etc., composed of nanofibers are widely used for commodities,
agricultural applications, apparel, industrial applications, etc.
Specifically, they are used in various fields such as artificial
leather, artificial suede, hygienic band, clothing, diapers,
packing material, miscellaneous goods, a variety of filter
material, medical materials for gene carriers, military material
like bulletproof vests and so on.
BACKGROUND ART
[0005] A conventional electrospinning devices and a process for
preparing nanofibers using the same have been disclosed in U.S.
Pat. No. 4,044,404. The conventional electrospinning devices
includes; a spinning dope main tank for storing a spinning dope; a
metering pump for quantitatively supplying the spinning dope; a
nozzle block having a plurality of nozzles aligned for discharging
the spinning dope; a collector positioned at the lower end of the
nozzles, for collecting the spun fibers; and a voltage generator
for generating a voltage.
[0006] The conventional process for preparing the nanofibers using
the electronic spinning devices will now be described in detail.
The spinning dope from the spinning dope main tank is consecutively
quantitatively provided to the plurality of nozzles supplied with a
high voltage through the metering pump.
[0007] Continuously, the spinning dope supplied to the nozzles is
spun and collected on the collector supplied with the high voltage
through the nozzles, thereby forming a single fiber web.
[0008] Continuously, the single fiber web is embossed or
needle-punched to prepare the non-woven fabric.
[0009] However, the conventional electrospinning devices and
process for preparing the non-woven fabric using the same have a
disadvantage in that an effect of electric force is reduced because
the spinning dope is consecutively supplied to the nozzles having
the high voltage.
[0010] In more detail, the electric force transmitted to the
nozzles is dispersed to the whole spinning dope, and thus fails to
overcome interface or surface tension of the spinning dopes. As a
result, fiber formation effects by the electric force are
deteriorated and the spinning dope is dropped in the form of drops
(hereinafter, referred to as "droplet"), which deteriorates the
quality of the product and hardly achieves mass production of the
fiber.
[0011] Moreover, in the conventional art, spinning is done at the
one-hole level in most cases, and thus mass production and
commercialization are not possible.
[0012] Moreover, the conventional electrospinning devices can
electrospin only one kind of polymer spinning dope through the
nozzles aligned in one nozzle block, and thus cannot effectively
satisfy various physical properties (features) of a nanofiber
non-woven fabric required according to purpose.
[0013] To solve the above problems, there have been proposed
methods, which prepare a conjugate nanofiber non-woven fabric by
installing several conventional electospinning devices in a row and
electrospinning two or more different kinds of polymer spinning
dope in each of the electrospinning devices, or which prepare a
conjugate nanofiber non-woven fabric by stacking two or more kinds
of nanofiber non-woven fabrics prepared in-the respective
electrospinning devices upon needle punching.
[0014] However, the above-described methods are problematic in that
the production facilities and production process are complicated
and the production cost increases.
[0015] It is therefore, an object of the present invention to
provide a conjugate electronic spinning devices which can
mass-produce nano fibers by enhancing fiber formation effects by
maximizing an electric force supplied to a nozzle block in
electronic spinning, namely maintaining the electric force higher
than interface or surface tension of a spinning dope, and which can
mass-produce nanofibers of high quality by effectively preventing a
droplet phenomenon.
[0016] It is another object of the present invention to provide a
conjugate electrospinning devices which can prepare a conjugate
nanofiber non-woven fabric and a conjugate nanofiber filament by
simple facilities and process because two ore more different kinds
of polymer spinning dope can be simultaneously electrospun through
nozzles aligned on one spinning block.
DISCLOSURE OF THE INVENTION
Technical Problem
[0017] The present invention provides a conjugate nanofiber
non-woven fabric and a conjugate nanofiber filament which have
physical properties suitable for purpose by simple facilities and
process by electrospinning two or more different kinds of polymer
spinning dope through nozzles aligned on one nozzle block.
[0018] Moreover, the present invention mass-produces two or more
kinds of nanofibers of high quality at a time by maximizing an
electric force in electrospinning and effectively preventing a
droplet phenomenon.
Technical Means to Solve the Problem
[0019] In order to achieve the above-described objects, there is
provided a conjugate electrospinning devices according to the
present invention, comprising: [I] nozzles for spinning two or more
different kinds of spinning dope aligned on a nozzle block 4
regularly or in random order in repetitive units at the same ratio
or in different ratios, aligned in random order at a predetermined
ratio, or aligned thereon in random order at a predetermined ratio,
or aligned thereon repetitively; [II] two or more spinning dope
main tanks 1; and [III] a spinning dope drop device 3 installed
between the spinning dope main tanks 1 and the nozzle block 4.
[0020] The present invention will now be described in detail with
reference to the accompanying drawings.
[0021] As shown in FIGS. 1 and 2, the conjugate electrospinning
devices of the present invention includes two or more spinning dope
main tanks 1 for storing two or more different spinning dopes; a
metering pump 2 for quantitatively supplying the spinning dope; a
nozzle block 4 having block-type nozzles 5 composed of a plurality
of pins, and discharging the spinning dope in a fiber shape; a
collector 7 positioned at the upper or lower part of the nozzle
block 4, for collecting spun single fibers; a voltage generator 9
for generating a high voltage; and a spinning dope discharger 12
connected to the top part of the nozzle block.
[0022] FIG. 1 is a schematic view illustrating a process of
preparing a conjugate nanofiber non-woven fabric using the
conjugate electrospinning devices in accordance with the present
invention. FIG. 2 is a schematic view illustrating a process of
preparing a conjugate nanofiber non-woven filament using the
conjugate electrospinning devices in accordance with the present
invention.
[0023] In the present invention, the nozzles for spinning two or
more different kinds of polymer spinning dope are aligned on the
nozzle block 4 regularly or in random order in repetitive units at
the same ratio or in different ratios. Preferably, the nozzles are
repetitively aligned on the nozzle block alternately in a row in
either transverse, longitudinal or diagonal direction.
[0024] FIG. 3 is a pattern diagram illustrating nozzles for
spinning two or more different kinds of polymer spinning dope
aligned on a nozzle block alternately in a row in a diagonal
direction. FIG. 4 is a pattern diagram illustrating nozzles for
spinning two or more different kinds of polymer spinning dope
aligned on a nozzle block regularly in repetitive units at the same
ratio or in different ratios in accordance with the present
invention. FIG. 5 is a pattern diagram illustrating nozzles for
spinning two or more different kinds of polymer spinning dope,
being aligned alternately in a row in a longitudinal direction and
supplying the spinning dope.
[0025] Moreover, in the present invention, as shown in FIGS. 1 and
2, the number of spinning dope main tanks 1 and 1' for storing and
supplying different polymer spinning dopes are two or more, and the
spinning dope drop device 3 is arranged between the spinning dope
main tanks and the nozzle blocks 4.
[0026] In the present invention, it is more preferable for mass
production that the outlets of the nozzles 5 installed on the
nozzle block 4 are formed in an upward direction, though they may
be formed in an upward direction as well as downward direction or
horizontal direction. It is more preferable for mass production
that the collector 7 is installed at an upper part of the nozzle
block 4, though they may be installed at an upper part as well as
lower part or horizontal position thereof.
[0027] Hereinafter, among the conjugate electrospinning devices of
the present invention, description will be made with respect to a
bottom up type electrospinning devices in which the outlets of
nozzles 5 installed on a nozzle block 4 are formed in an upward
direction, and a collector 7 is positioned at an upper part of the
nozzle block 4. However, the present invention is not limited to
the bottom up type electrospinning devices.
[0028] As shown in FIG. 6, the nozzle block 4 of the present
invention includes: [I] a nozzle plate 4f on which nozzles 5 for
spinning different spinning dopes are aligned regularly or in
random order in repetitive units in the same ratio or in different
ratios and two or more spinning dope supply plates 4h and 4h'
positioned at the lower end of the nozzle plate and for supplying
the spinning dope to the nozzles; [II] overflow removal nozzles 4a
surrounding the nozzles 5, an overflow temporary storage plate 4g
connected to the overflow removal nozzles and positioned at the
right upper end of the nozzle plate and an overflow removal nozzle
supporting plate 4e positioned at the right upper end of the
overflow temporary storage plate and supporting the overflow
removal nozzles; [III] air supply nozzles 4b surrounding the
nozzles 5 and the overflow removal nozzles 4a, an air supply nozzle
supporting plate 4c positioned at the top end of the nozzle block
and supporting the air supply nozzles, and an air storage plate 4d
positioned at the right lower end of the air supply nozzle
supporting plate and supplying air to the air supply nozzles; [IV]
a conductor plate 4i having pins aligned in the same way as the
nozzles and positioned at the right lower end of the nozzle plate;
and [V] a heating plate 4j positioned at the right lower end of the
spinning dope supply plate.
[0029] As shown in FIG. 6, the overflow removal nozzles 4a for
removing unspun spinning dope and the air supply nozzle 4b for
supplying air in order to increase the cumulative distribution of
nanofibers are sequentially arranged around the nozzles 5 for
electrospinning spinning dopes on the collector, thereby forming a
triple tube shape.
[0030] Moreover, the nozzles 5 for spinning different spinning
dopes are aligned on the nozzle block 4 of FIG. 6 alternately in a
row in a diagonal direction.
[0031] As shown in FIGS. 8 and 10, the outlets of the nozzles 5 for
electrospinning the spinning dopes on the collector are enlarged in
the shape of one or more flared tubes. At this time, the angle
.theta. of the nozzle 90 to 175.degree., more preferably, 95 to
150.degree., is preferable so that the outlets of the nozzles 5 can
form spinning dope drops of the same shape in the outlets of the
nozzles 5.
[0032] If the angle .theta. of the nozzle outlet exceeds
175.degree., bigger drops are formed in the nozzle regions, thereby
increasing the surface tension. As a result, in order to form
nanofibers, a higher voltage is required. As spinning begins not at
the center regions of drops, but at the edge parts of drops, the
center regions of the drops are solidified, and this may block the
nozzles.
[0033] Meanwhile, if the angle .theta. of the nozzle outlet is less
than 90.degree., drops formed at the nozzle outlet regions becomes
very smaller. Therefore, when an electric field becomes
instantaneously irregular, or an electric field is slightly
irregularly supplied to the nozzle outlet regions, fibers cannot be
formed because drop forms are not normal, thereby bringing about a
droplet phenomenon.
[0034] In the present invention, a nozzle length (L, L.sub.1,
L.sub.2) is not specifically limited.
[0035] However, it is preferred that the nozzle inner diameter (Di)
is 0.01 to 5 mm and the nozzle outer diameter Do is 0.01 to 5 mm.
If the nozzle inner diameter or nozzle outer diameter is less than
0.01 mm, the droplet phenomenon frequently occurs, and if the
nozzle inner diameter or nozzle outer diameter exceeds 5 mm, fiber
formation may be impossible.
[0036] FIGS. 8 and 9 illustrate the lateral side and plane of a
nozzle having one enlarged part (angle) formed at a nozzle outlet,
and FIGS. 10 and 11 illustrate the lateral side and plane of a
nozzle having two enlarged parts (angle) formed at a nozzle outlet.
That is, .theta..sub.1 as illustrated in FIG. 10 is the angle of a
first nozzle outlet which is a part for spinning the spinning dope,
and .theta..sub.2 is the angle of a second nozzle outlet which is a
part for supplying the spinning dope.
[0037] The nozzles 5 in the nozzle block 4 are aligned in plural
number on the nozzle plate 4f, and the overflow removal nozzles 4a
surrounding them and the air supply nozzles 4b are sequentially
installed outside of the nozzles 5.
[0038] The overflow removal nozzles 4a are provided for the purpose
of preventing a droplet phenomenon, which occurs in the event that
not every spinning dope formed in excessive amount at the outlets
of the nozzles 5 is fiberized, and recovering an overflowing
spinning dope, and it serves to collect an unfiberized spinning
dope at the nozzle outlets and feed it to the overflow temporary
storage plate 4g positioned at the right lower end of the nozzle
plate 4f.
[0039] Of course, the overflow removal nozzles 4a have a larger
diameter than the nozzles 5, and are preferably made of insulating
material.
[0040] The overflow temporary storage plate 4g is made of
insulating material, and serves to temporally store a residual
spinning dope introduced through the overflow removal nozzles 4a
and then feed it to the spinning dope supply plate 4h.
[0041] The air storage plate 4d for supplying air is positioned at
the upper end of the overflow temporary storage plate 4 g, and
supplies air to the air supply nozzles 4b surrounding the nozzles 5
and the overflow removal nozzles 4a. The air supply nozzle
supporting plate 4c is installed on the top layer of the nozzle
block 4 having the air supply nozzles 4b aligned thereon, and the
supporting plate 4c is composed of non-conductive material. The air
supply nozzle supporting plate 4c is positioned at the nozzle
block, and thus an electric force applied between the collector 7
and the nozzles 5 is only concentrated on the nozzles 5 so that
spinning can be done smoothly only in the nozzle 5 regions.
[0042] The distance h from the upper tip of the nozzles 5 to the
upper tip of the air supply nozzles 4b is 1 to 20 mm, preferably, 2
to 15 mm. In other words, the height of the air supply nozzles 4b
is set 1 to 20 mm, preferably, 2 to 15 mm, greater than that of the
nozzles 5. If h is 0, that is, the air supply nozzles 4b are
positioned at the same height as the nozzles 5, jet streams are not
effectively formed in the nozzle 5 regions, thereby reducing the
area of nanofibers attached on the collector 7. Meanwhile, if h
exceeds 20 mm, electric force becomes weaker due to a high voltage
applied between the collector and the nozzles, thereby
deteriorating the formation performance of nanofibers and making
the length or formation pattern of jet streams unstable.
Concretely, a Taylor cone disturbs the stability of a jet stream
forming region. Consequently, it is difficult to spin nanofibers
smoothly.
[0043] The speed of air in the air supply nozzles 4b is 0.05 to 50
m/sec, more preferably, 1 to 30 m/sec. If the air speed is less
than 0.05 m/sec, the dispersibility of nanofibers collected on the
collector is low, and thus the collecting area is not increased
much. If the air speed exceeds 50 m/sec, the area of nanofibers
collected on the collector is decreased due to a too high air
speed, and thus the collection uniformity of the nanofibers is
deteriorated.
[0044] The conductor plate 4i having pins aligned in the same way
as the nozzles is installed at the right lower end of the nozzle
plate 4f, and the voltage generator 9 is connected to the conductor
plate 4i.
[0045] An indirect heating type heater (not shown) is installed at
the right lower end of the spinning dope supply plate 4h.
[0046] The conductor plate 4i serves to apply a high voltage to the
nozzles 5, and the spinning dope storage plate 4h serves to store
the spinning dope introduced to the nozzle block 4 from the
spinning dope drop device 3 and then supply it to the nozzles 5. At
this time, it is preferable that the spinning dope supply tube 4h
is made with a minimum space so as to minimize the storage quantity
of the spinning dope.
[0047] Meanwhile, the spinning dope drop device 3 of the present
invention is designed to have an overally sealed cylindrical shape
as shown in FIGS. 12(a) and 12(b), and serves to supply the
spinning dope continuously inlet from the spinning dope main tank 1
to the nozzle block 4 in the form of drops.
[0048] The spinning dope drop device 3 is designed to have an
overally sealed cylindrical shape as shown in FIGS. 12(a) and
12(b). FIG. 12(a) is a cross sectional view of the spinning dope
drop device. FIG. 12(b) is a perspective view of the spinning dope
drop device. A spinning dope inducing tube 3c for inducing the
spinning dope to the nozzle block and a gas inletting tube 3b are
arranged side by side at the upper end of the spinning dope drop
device 3. Here, the spinning dope inducing tube 3c is formed
slightly longer than the gas inletting tube 3b.
[0049] The gas inlets from the lower end of the gas inletting tube,
and an initial gas inletting portion of the gas inletting tube is
connected to a filter 3d. A spinning dope discharge tube 3d for
discharging the dropped spinning dope to the nozzle block 4 is
formed at the lower end of the spinning dope drop device 3. The
center portion of the spinning dope drop device 3 is hollow shape
so that the spinning dope can be dropped from the end of the
spinning dope inducing tube 3c.
[0050] The spinning dope induced into the spinning dope drop device
3 is flown through the spinning dope inducing tube 3c, but dropped
at the end thereof. Therefore, flowing of the spinning dope is
intercepted at least one time.
[0051] The principle of dropping the spinning dope will now be
explained in detail. When the gas inlets into the upper end of the
spinning dope drop device 3 through the filter 3d and the gas
inletting tube 3b, a pressure of the spinning dope inducing tube 3c
becomes irregular due to gas eddy. Such a pressure difference drops
the spinning dope.
[0052] An inert gas such as nitrogen or air can be used as the
gas.
[0053] The entire parts of the nozzle block 4 of the present
invention reciprocates in a direction perpendicular to the
traveling direction of nanofibers electrospun by a nozzle block
bilateral reciprocating device 10 in order to make uniform the
dispersion of electrospun nanofibers.
[0054] An agitator 11c for agitating the spinning dope stored in
the nozzle block 4 is installed in the nozzle block 4, more
specifically, in the spinning dope supply plate 4h in order to
prevent the spinning dope from gelation.
[0055] The agitator 11c is connected to an agitator motor 11a by a
non-conductive insulating rod 11b.
[0056] As the agitator 11c is located in the nozzle block 4, it can
effectively prevent the spinning dope in the nozzle block 4 from
gelation when spinning a dope containing inorganic metal or
electrospinning a spinning dope dissolved using a mixed solvent for
a long time.
[0057] A spinning dope discharger 12 for forcibly feeding the
spinning dope excessively supplied to the nozzle block to the
spinning dope main tank 1 is connected to the top part of the
nozzle block 4.
[0058] The spinning dope discharger 12 forcibly feeds the spinning
dope excessively supplied into the nozzle block to the spinning
dope main tank 1 by suction air.
[0059] A heater (not shown) of direct heating type or indirect
heating type is installed (attached) to the collector 7 of the
present invention, and the collector is fixed or continuously
rotates.
[0060] Next, the process of preparing a conjugate nanofiber
non-woven fabric using the conjugate electrospinning devices of the
present invention will be described with reference to FIG. 1.
[0061] Firstly, two kinds of thermoplastic or thermosetting resin
spinning dope respectively stored in the two main tanks 1 and 1'
are measured by the respective metering pumps 2 and 2', and
quantitatively supplied to the respective spinning dope drop
devices 3 and 3'. Exemplary thermoplastic or thermosetting resins
used to prepare the spinning dopes include polyester resins, acryl
resins, phenol resins, epoxy resins, nylon resins,
poly(glycolide/L-lactide) copolymers, poly(L-lactide) resins,
polyvinyl alcohol resins and polyvinyl chloride resins. A resin
molten solution or resin solution may be used as the spinning
dopes.
[0062] When the spinning dopes supplied to the spinning dope drop
devices 3 and 3' passes through the spinning dope drop devices 3
and 3', flowing of the spinning dopes is dropped at least once in
the mechanism described above. Thereafter, the spinning dopes are
supplied to the spinning dope supply plate 4h of the nozzle block 4
having a high voltage and having the agitator tic installed
thereto. The spinning dope drop devices 3 and 3' serve to prevent
electricity from flowing in the spinning dope main tanks 1 and 1'
by intercepting flowing of the spinning dopes.
[0063] The nozzle block 4 discharges the respective spinning dopes
in a bottom-up fashion through the nozzles aligned alternately in a
row in a diagonal direction. The spinning dopes are collected by
the collector 7 supplied with the high voltage to prepare a
non-woven fabric web.
[0064] The spinning dopes fed to the spinning dope supply tube 4h
are discharged to the upper part of the collector 7 through the
nozzles 5 to form fibers. At this time, the nanofibers electrospun
from the nozzles 5 are widely spread by air sprayed from the air
supply nozzles 4b and collected on the collector 7, and thus the
collection area becomes wider and the cumulative density becomes
uniform. The excessive spinning dope not fiberized in the nozzles 5
is collected in the overflow removal nozzles 4a, passes through the
overflow temporary storage plate 4 g, and is moved back to the
spinning dope supply plate 4h.
[0065] Moreover, the spinning dope excessively supplied to the top
part of the nozzle block is forcibly fed to the spinning dope main
tanks 1 and 1' by the spinning dope dischargers 12 and 12'.
[0066] Here, to facilitate fiber formation by the electric force, a
voltage over 1 kV, more preferably 20 kV is generated by the
voltage generator 6 and transmitted to the conductor plate 4i and
the collector 7 installed at the lower end of the nozzle block 4.
It is advantageous in productivity to use an endless belt as the
collector 7. It is preferable that the collector 7 reciprocates a
predetermined distance to the left and right in order to make
uniform the density of the non-woven fabric.
[0067] The nanofiber web 5 formed on the collector 7 is
consecutively processed by an web supporting roller 14, and the
prepared non-woven fabric winds on a winding roller 16. Thus, the
preparation of the non-woven fabric is finished.
[0068] The conjugate nanofiber non-woven fabric prepared by the
devices of the present invention can easily satisfy the physical
properties suitable for various purposes by adjusting the type and
ratio of spinning dope. As a result, the conjugate nanofiber
non-woven fabric of the present invention is used for various
purposes including artificial leather, medical materials such as
hygienic band, filter, artificial blood vessel, etc., winter vest,
semiconductor wipers, non-woven fabrics for batteries and so
on.
[0069] Next, the process of preparing a conjugate nanofiber
filament using the conjugate electrospinning devices of the present
invention will now be described with reference to FIG. 2.
[0070] As shown in FIG. 2, a conjugate nanofiber filament is
prepared by firstly preparing a nanofiber web 15 in the same way as
in the preparation of the above-described conjugate nanofiber
non-woven fabric, twisting the prepared nanofiber web 15 while
passing it though an air twisting machine 18, drawing it while
sequentially passing it through a first roller 19, a second roller
20 and a third roller 22, and then winding it on a winding roller
16.
[0071] Optionally, the prepared nanofiber web may be drawn by a
thermosetting machine 21 between the drawing and winding steps.
[0072] At this time, the above nanofiber web 15 is in a ribbon
form.
[0073] In order to prepare a ribbon shaped nanofiber web 15, there
is used a method (I) in which the nanofiber web 15 is electrospun
at a large width which is the same as the entire width of the
collector 7 and then the nanofiber web having the large width is
cut by a web cutting machine, or a method (II) in which the
nanofiber web 15 is divided at small widths which are the same as
the width of the nozzle block 4.
Advantageous Effects
[0074] The present invention can mass-produce two or more kinds of
high quality nanofibers, and can produce a conjugate nanofiber
non-woven fabric and a conjugate nanofiber filament suitable for
the physical properties required for each purpose by simple
facility and process.
BRIEF DESCRIPTION OF THE DRAWINGS
[0075] FIG. 1 is a schematic view illustrating a process of
preparing a conjugate nanofiber non-woven fabric using the
conjugate electrospinning devices in accordance with the present
invention;
[0076] FIG. 2 is a schematic view illustrating a process of
preparing a discontinuous filament composed of conjugate nanofibers
using the conjugate electrospinning devices in accordance with the
present invention;
[0077] FIG. 3 is a pattern diagram illustrating nozzles for
spinning two or more different kinds of polymer spinning dope
aligned on a nozzle block alternately in a row in a diagonal
direction in accordance with the present invention (.largecircle.:
one spinning dope component, : another spinning dope
component);
[0078] FIG. 4 is a pattern diagram illustrating nozzles for
spinning two or more different kinds of polymer spinning dope
aligned on a nozzle block regularly in repetitive units at the same
ratio or in different ratios in accordance with the present
invention (.largecircle.: one spinning dope component, : another
spinning dope component);
[0079] FIG. 5 is a pattern diagram illustrating nozzles for
spinning two or more different kinds of polymer spinning dope,
being aligned on a nozzle block alternately in a row in a
longitudinal direction and supplying the spinning dope in
accordance with the present invention (.largecircle.: one spinning
dope component, : another spinning dope component);
[0080] FIG. 6 is a pattern diagram of the nozzle block 4 in
accordance with the present invention;
[0081] FIG. 7 is a cross sectional diagram of the nozzle block 4 in
accordance with the present invention;
[0082] FIG. 8 and FIG. 10 are pattern diagrams illustrating a side
of the nozzle 5;
[0083] FIG. 9 and FIG. 11 are exemplary views of a plane of the
nozzle 5;
[0084] FIG. 12(a) is a cross sectional view of a spinning dope drop
device 3 in the present invention;
[0085] FIG. 12(b) is a perspective view of the spinning dope drop
device 3 in the present invention;
[0086] FIG. 13 is a strength-elongation graph for each kind (type)
of nanofiber non-woven fabric;
[0087] FIG. 14 is a tear strength graph for each kind (type) of
nanofiber non-woven fabric.
[0088] Explanation of Reference Numerals for Main Parts in the
Drawings [0089] 1,1': spinning dope main tank 2,2': metering pump
3,3': spinning dope drop device [0090] 3a: filter of spinning dope
drop device 3b: air inletting tube 3c: spinning dope inducing tube
[0091] 3d: spinning dope discharge tube 4: nozzle block 4a:
overflow removal nozzle [0092] 4b: air supply nozzle 4c: air supply
nozzle supporting plate (non-conductive material) [0093] 4d: air
storage plate 4e: overflow removal nozzle supporting plate [0094]
4f: nozzle plate 4g: overflow temporary storage plate [0095]
4h,4h': spinning dope supply plate 4i: conductor plate 4j: heating
plate [0096] 5: nozzle 6: nanofiber 7: collector (conveyer belt)
[0097] 8a,8b: collector supporting roller 9: voltage generator 9b:
discharge device [0098] 10: nozzle block bilateral reciprocating
device 11a: motor for agitator 11c [0099] 11b: non-conductive
insulating rod 11c: agitator 12,12': spinning dope discharger
[0100] 13: feed pipe 14: web supporting roller 15: nanofiber web
[0101] 16: winding roller 17: web feed roller 18: air twisting
machine [0102] 19: first roller 20: second roller 21: thermosetting
machine (heater) [0103] 22: third roller W: conjugate nanofiber
non-woven fabric prepared by Example 1 [0104] X: conjugate
nanofiber non-woven fabric prepared by Example 2 [0105] Y:
nanofiber non-woven fabric prepared by Comparative Example 1 [0106]
Z: nanofiber non-woven fabric prepared by Comparative Example 2
[0107] .theta.: nozzle outlet angle [0108] L: nozzle length Di:
nozzle inner diameter Do: nozzle outer diameter [0109] h: distance
from upper tip of nozzles to upper tip of air supply nozzles
BEST MODE FOR CARRYING OUT THE INVENTION
[0110] 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
[0111] Poly (.epsilon.-caprolactone) polymer (product of Aldrich,
USA) having a number average molecular weight of 80,000 was
dissolved in a mixed solvent of methylene chloride and N,N-dimethyl
formamide (volume ratio: 75/25) at a concentration of 13 wt %, to
prepare a spinning dope. The surface tension of the polymer
spinning dope was 35 mN/m, the spinning dope viscosity was 35
centipoises at a room temperature, the electric conductivity was
0.02 mS/m, and the permittivity was 90.
[0112] Polyurethane resin (Pellethane 2103-80AE of Dow Chemical
Company) having a number average molecular weight of 80,000 was
dissolved in N,N dimethyl formamide at 8 wt. %.
[0113] The two kinds of spinning dopes were stored in the main
tanks 1 and 1', quantitatively measured by the metering pumps 2 and
2', and supplied to the spinning dope drop devices 3 and 3',
thereby discontinuously changing the flow of the spinning dopes.
Thereafter, the spinning dopes were supplied to the nozzle block 4
as shown in FIG. 6, and electrospun in a bottom-up fashion in a
fiber shape through the nozzles 5. The spun fibers were collected
on the collector 7, to prepare a nanofiber web 15. The prepared
nanofiber web 15 passed through the web supporting roller 14, and
wound on the winding roller 16, to prepare a conjugate nanofiber
non-woven fabric. The nozzles for spinning the two kinds of
spinning dopes are aligned on the nozzle block 4 as shown in FIG.
4. Thus, the percentage of the number of nozzles for spinning the
poly (.epsilon.-caprolactone) spinning dope to the total number of
nozzles was 66.7%, and the percentage of the number of nozzles for
spinning the polyurethane resin spinning dope was 33.3%. Here, each
nozzle block included 9,720 nozzles, and four nozzle blocks were
employed, the total number of nozzles was 38,880, the spinning
distance was 15 cm, and the nozzle block 4 reciprocates at 2 m/min.
An electric heater was installed on the collector 7 and thus the
surface temperature of the collector was 35.degree. C. when
performing electrospinning. The spinning dope overflowing the top
part of the nozzle block 4 during the spinning process was forcibly
fed to the spinning dope main tank 1 by using the spinning dope
discharger 12 using suction air. The angle .theta. of the nozzle
outlets was 120.degree., the inner diameter Di of the nozzles was
0.9 mm, and the outer diameter thereof was 1 mm. The inner diameter
of the air supply nozzles was 20 mm, the outer diameter thereof was
23 mm, and the distance h from the upper tip of the nozzles 5 to
the upper tip of the air supply nozzles 4b was 8 mm. The air speed
was 10 m/ sec. Model CH 50 of Symco Corporation was used as the
voltage generator. The strength-elongation graph of the conjugate
nanofiber non-woven fabric W thus prepared was shown in FIG. 13,
and the tear strength graph thereof was shown in FIG. 14.
EXAMPLE 2
[0114] Poly (.epsilon.-caprolactone) polymer (product of Aldrich,
USA) having a number average molecular weight of 80,000 was
dissolved in a mixed solvent of methylene chloride and N,N-dimethyl
formamide (volume ratio: 75/25) at a concentration of 13 wt %, to
prepare a spinning dope. The surface tension of the polymer
spinning dope was 35 mN/m, the spinning dope viscosity was 35
centipoises at a room temperature, the electric conductivity was
0.02 mS/m, and the permittivity was 90.
[0115] Polyurethane resin (Pellethane 2103-80AE of Dow Chemical
Company) having a number average molecular weight of 80,000 was
dissolved in N,N dimethyl formamide at 8 wt. %.
[0116] The two kinds of spinning dopes were stored in the main
tanks 1 and 1', quantitatively measured by the metering pumps 2 and
2', and supplied to the spinning dope drop devices 3 and 3',
thereby discontinuously changing the flow of the spinning dopes.
Thereafter, the spinning dopes were supplied to the nozzle block 4
as shown in FIG. 6, and electrospun in a bottom-up fashion in a
fiber shape through the nozzles. The spun fibers were collected on
the collector 7, to prepare a nanofiber web 15. The prepared
nanofiber web 15 passed through the web supporting roller 14, and
wound on the winding roller 16, to prepare a conjugate nanofiber
non-woven fabric. The nozzles for spinning the two kinds of
spinning dopes are aligned on the nozzle block 4 as shown in FIG.
4. Thus, the percentage of the number of nozzles for spinning the
poly (.epsilon.-caprolactone) spinning dope to the total number of
nozzles was 33.3%, and the percentage of the number of nozzles for
spinning the polyurethane resin spinning dope was 66.7%. Here, each
nozzle block included 9,720 nozzles, and four nozzle blocks were
employed, the total number of nozzles was 38,880, the spinning
distance was 15 cm and the nozzle block 4 reciprocates at 2 m/min.
An electric heater was installed on the collector 7 and thus the
surface temperature of the collector was 35.degree. C. when
performing electrospinning. The spinning dope overflowing the top
part of the nozzle block 4 during the spinning process was forcibly
fed to the spinning dope main tank 1 by using the spinning dope
discharger 12 using suction air. The angle .theta. of the nozzle
outlets was 120.degree., the inner diameter Di of the nozzles was
0.9 mm, and the outer diameter thereof was 1 mm. The inner diameter
of the air supply nozzles was 20 mm, the outer diameter thereof was
23 mm, and the distance h from the upper tip of the nozzles 5 to
the upper tip of the air supply nozzles 4b was 8 mm. The air speed
was 10 m/sec. Model CH 50 of Symco Corporation was used as the
voltage generator. The strength-elongation graph of the conjugate
nanofiber non-woven fabric X thus prepared was shown in FIG. 13,
and the tear strength graph thereof was shown in FIG. 14.
COMPARATIVE EXAMPLE 1
[0117] Poly (.epsilon.-caprolactone) polymer (product of Aldrich,
USA) having a number average molecular weight of 80,000 was
dissolved in a mixed solvent of methylene chloride and N,N-dimethyl
formamide (volume ratio: 75/25) at a concentration of 13 wt %, to
prepare a spinning dope. The surface tension of the polymer
spinning dope was 35 mN/m, the spinning dope viscosity was 35
centipoises at a room temperature, the electric conductivity was
0.02 mS/m, and the permittivity was 90.
[0118] The spinning dope was stored in the main tank 1 of a typical
bottom up type electrospinning devices, quantitatively measured by
the metering pump 2, and supplied to the nozzle block 4 having a
voltage of 35 kV, and electrospun in a bottom-up fashion in a fiber
shape through the nozzles 5. The spun fibers were collected on the
collector 7, to prepare a nanofiber web 15. The prepared nanofiber
web 15 passed through the web supporting roller 14, and wound on
the winding roller 16, to prepare a conjugate nanofiber non-woven
fabric. The nozzles for spinning the one kind of spinning dope are
diagonally aligned on the nozzle block 4. Here, each nozzle block
included 9,720 nozzles, and four nozzle blocks were employed, the
total number of nozzles was 38,880, the spinning distance was 15 cm
and the discharge amount of one nozzle was 1.2 mg/min, and the
nozzle block 4 reciprocates at 2 m/min An electric heater was
installed on the collector 7 and thus the surface temperature of
the collector was 35.degree. C. when performing electrospinning.
The spinning dope overflowing the top part of the nozzle block 4
during the spinning process was forcibly fed to the spinning dope
main tank 1 by using the spinning dope discharger 12 using suction
air. The angle .theta. of the nozzle outlets was 120.degree., the
inner diameter Di of the nozzles was 0.9 mm, and the outer diameter
thereof was 1 mm. The inner diameter of the air supply nozzles was
20 mm, the outer diameter thereof was 23 mm, and the distance h
from the upper tip of the nozzles 5 to the upper tip of the air
supply nozzles 4b was 8 mm. The air speed was 10 m/ sec. Model CH
50 of Symco Corporation was used as the voltage generator. The
strength-elongation graph of the conjugate nanofiber non-woven
fabric Y thus prepared was shown in FIG. 13, and the tear strength
graph thereof was shown in FIG. 14.
COMPARATIVE EXAMPLE 2
[0119] Polyurethane resin (Pellethane 2103-80AE of Dow Chemical
Company) having a number average molecular weight of 80,000 was
dissolved in N,N dimethyl formamide at 8 wt. %.
[0120] The spinning dope was stored in the main tank 1 of a typical
bottom up type electrospinning devices, quantitatively measured by
the metering pump 2, and supplied to the nozzle block 4 having a
voltage of 35 kV, and electrospun in a bottom-up fashion in a fiber
shape through the nozzles 5. The spun fibers were collected on the
collector 7, to prepare a nanofiber web 15. The prepared nanofiber
web 15 passed through the web supporting roller 14, and wound on
the winding roller 16, to prepare a conjugate nanofiber non-woven
fabric. The nozzles for spinning the one kind of spinning dope are
diagonally aligned on the nozzle block 4. Here, each nozzle block
included 9,720 nozzles, and four nozzle blocks were employed, the
total number of nozzles was 38,880, the spinning distance was 15 cm
and the discharge amount of one nozzle was 1.2 mg/min, and the
nozzle block 4 reciprocates at 2 m/min. An electric heater was
installed on the collector 7 and thus the surface temperature of
the collector was 35.degree. C. when performing electrospinning.
The spinning dope overflowing the top part of the nozzle block 4
during the spinning process was forcibly fed to the spinning dope
main tank 1 by using the spinning dope discharger 12 using suction
air. The angle .theta. of the nozzle outlets was 120.degree., the
inner diameter Di of the nozzles was 0.9 mm, and the outer diameter
thereof was 1 mm. The inner diameter of the air supply nozzles was
20 mm, the outer diameter thereof was 23 mm, and the distance h
from the upper tip of the nozzles 5 to the upper tip of the air
supply nozzles 4b was 8 mm. The air speed was 10 m/ sec. Model CH
50 of Symco Corporation was used as the voltage generator. The
strength-elongation graph of the conjugate nanofiber non-woven
fabric Z thus prepared was shown in FIG. 13, and the tear strength
graph thereof was shown in FIG. 14.
INDUSTRIAL APPLICABILITY
[0121] The present invention can be utilized for producing a
conjugate nanofiber non-woven fabric and a conjugate nanofiber
filament which are used as commodities such as artificial leather,
air cleaning filter, wiping cloth, golf glove, wig, etc. and
various industrial materials such as artificial filter for
dialysis, artificial blood vessel, anti-adhesion agent, artificial
bone, etc. because it has physical properties required for each
purpose.
* * * * *