JP4871711B2 - Method for producing organic fiber using electrostatic spraying method - Google Patents

Description

  The present invention relates to a method for fiberizing an organic substance by an electrostatic spraying method, and relates to a method for producing a stretchable organic fiber having directionality in the fiber array.

  The electrostatic spraying method is a kind of fiber manufacturing method using a high voltage, and is characterized in that it can manufacture uniform and fine fibers. In this electrostatic spraying method, an electrostatically sprayed organic substance solution is solidified by receiving solvent removal due to charge repulsion.

  As a fiber manufacturing method using such an electrostatic spraying method, Patent Document 1 discloses a method for manufacturing a fiber structure from a zein protein solution.

  Patent Document 2 discloses a step of supplying a spinning polymer solution to a spinning space, a step of supplying a first air stream in a direction of supplying the polymer solution, and a fiber formed by supplying the fibers. Irradiating with ions of the opposite polarity, and recovering the fibers while supplying a second air stream in a direction intersecting the direction of supplying the polymer solution and recovering the spun fibers; The manufacturing method of the fiber assembly characterized by including these is disclosed.

In addition, an electrostatic spinning method characterized by maintaining the spinning space at 1.5 to 100 atm is disclosed in Patent Document 3, and the formed fiber is irradiated with ions having a polarity opposite to that of the fiber. An electrostatic spinning method is disclosed in Patent Document 4.
JP 2005-290631 A JP 2005-264374 A JP 2004-256974 A Japanese Patent Application Laid-Open No. 2004-238749

  However, in the electrospinning method, nano-sized fibers formed at a high speed are laminated on an assembly that is an electrode target, so that it is likely to be felt and it is difficult to take out fine fibers (nanofibers) as a thread. For this reason, there exists a fault that it cannot utilize as a general fiber.

  On the other hand, in a fiber forming process such as a melt spinning method, oriented fibers of the molecules are promoted by stretching the fibers formed by spinning, thereby increasing the strength of the fibers. However, in the fiber manufacturing method using the electrospinning method in which fine fibers are difficult to be taken out as a filament, improvement in physical properties due to fiber drawing cannot be expected.

  An object of the present invention is to fiberize an organic substance in a stretchable state using an electrostatic spray method.

  The present inventor, when electrostatically spraying an organic material solution, electrostatically sprays toward the surface of the aggregate while rotating the aggregate having protrusions on the surface. Have been found to accumulate as fibers. Further, it was found that the fibers can be drawn by removing the fibers accumulated on the surface of the aggregate, and the present invention has been completed.

Specifically, the present invention
A preparation process for preparing a spinning solution in which an organic substance is dissolved in an organic solvent;
An electrostatic spraying step in which a high voltage is applied to the spinning solution while rotating an assembly having protrusions on the surface, and electrostatic spraying is performed toward the vicinity of the rotation axis of the assembly;
A separation step of removing fibers accumulated on the surface of the aggregate from the aggregate;
A method for producing an organic fiber having
The stack has a plurality of projections are arranged in parallel so as to be orthogonal to the direction of rotation, about the manufacturing method of the organic fibers.

When electrostatic spraying of an organic substance is performed while rotating an aggregate having projections on the surface, fibers are collected in a felt-like shape on the projections and linearly aligned between the projections. Precipitation). In the present invention, the plurality of protrusions are arranged in parallel so as to be orthogonal to the rotation direction. This is because it is easy to regularly arrange the felt-like accumulation portion and the linear accumulation portion connecting the felt-like accumulation portions.

In the electrostatic spraying process, a high voltage is applied to the spinning liquid while rotating the ring-shaped aggregate having a protrusion on the surface and rotated by two rotation shafts, and the rotation of the ring-shaped aggregate is performed. it is not preferable to electrostatically sprayed toward near the axis.

  In the case where the accumulation body is in the shape of a ring rotated by two rotation shafts, such an effect can be obtained by electrostatically spraying the organic substance solution toward the vicinity of the rotation shaft (end portion of the accumulation body). That is, it is possible to give directionality to the organic fibers to be accumulated only when the organic substance is electrostatically sprayed from a specific direction on the accumulated body rotating like a belt conveyor. And if the accumulated fiber is removed from the surface of the aggregate, it can be stretched in the length direction and can be reinforced as a single fiber bundle.

Further, in the electrostatic spraying step, a high voltage is applied to the spinning liquid while rotating a cylindrical accumulation body having protrusions on the surface of the side surface about a line connecting the centers of the bottom surfaces thereof, and the cylinder it is also not preferable to electrostatically sprayed toward the side surface shaped for aggregation.

  In the case where the accumulation body is cylindrical, by performing electrostatic spraying while rotating the accumulation body toward the side surface of the accumulation body on which the protrusion is formed, the protrusion has a felt shape and a protrusion. The fibers accumulate (precipitate) in a linearly aligned state between the portion and the protrusion. In this case, it is necessary for the cylindrical accumulation body to have a line connecting the centers of the bottom surfaces as the rotation center.

Vertical cross section of the protrusions have preferably be substantially rectangular or triangular.

Wherein the aggregate has preferably be applying a ground. In the organic fiber manufacturing method of the present invention, unlike the conventional method of fiberizing an organic substance using an electrostatic spraying method, it is not necessary to ground the integrated body, and the integrated body need not be conductive. . However, there is an advantage that the efficiency of collecting fibers is higher when grounding is applied to the assembly.

  According to the method for producing a fiber bundle of the present invention, it is possible to produce fine fibers produced by an electrostatic spray method, which has conventionally been difficult to take out as a yarn and cannot be used as a general fiber, in a stretchable state. it can.

  Embodiments of the present invention will be described below with reference to the drawings as appropriate. The present invention is not limited to these.

  The schematic flowchart of the manufacturing method of the organic fiber of this invention is shown in FIG.

  First, as step S1, a spinning solution in which an organic substance is dissolved in an organic solvent is prepared (preparation step). The organic substance and the organic solvent can be used in the present invention without particular limitation as long as they can be fiberized by electrostatic spraying.

  Next, as step S2, a high voltage is applied to the spinning liquid while rotating the assembly having protrusions on the surface to electrostatically spray the assembly (electrostatic spraying step). When an organic material spinning solution is electrostatically sprayed using a metal mesh, metal plate or the like with an earth as an aggregate, the fibers are felt and cannot be taken out as “threads”.

  However, in the present invention, fibers are accumulated in a specific state on the surface of the aggregate by applying a high voltage to the spinning liquid and performing electrostatic spraying while rotating the aggregate having protrusions on the surface. It is characterized by that. That is, the fibers are accumulated in a felt shape on the protrusions, and the fibers are accumulated in a state of being aligned between the protrusions.

  The shape of the aggregate is not particularly limited as long as protrusions (protrusions) are formed on the surface, but in order to collect fibers uniformly on the surface while rotating, it is rotated by two rotating shafts. It is preferably a ring shape (belt shape) or a cylindrical shape having the center of the bottom surface as the center of rotation.

  In the case of the belt-like integrated body 1, it is rotated in the state shown in FIG. 2 by two rotating shafts (the rotating shaft 2 and the rotating shaft 3). Then, electrostatic spraying is performed toward the rotating accumulation body from the vicinity of the rotation axis (position of nozzle A or nozzle B). At this time, when electrostatic spraying is performed toward a position away from the rotation axis, for example, the accumulated body rotating from the position of the nozzle C, the fibers are only accumulated in a felt shape on the surface of the accumulated body. .

  On the other hand, in the case of the cylindrical accumulation body 4, as shown in FIG. 3, the accumulation body is rotated with a straight line connecting the two centers (6a and 6b) of the bottom surfaces 5a and 5b as the rotation center. Then, electrostatic spraying is performed from the position of the nozzle D toward the cylindrical accumulation body side surface.

  Here, the ring-shaped (belt-shaped) integrated body 1 will be described as an example of the protrusions on the surface of the integrated body. Examples of top views of the belt-like integrated body 1 viewed from the position of the nozzle C in FIG. 2 are shown in FIGS. 4 (a) to 4 (c). In the case of the belt-like accumulation body 1, a plurality of protrusions may be arranged in parallel so as to be orthogonal to the rotation direction of the accumulation body. On the other hand, as shown in FIG. 5, if a plurality of protrusions are arranged in parallel so as to be parallel to the rotation direction, the fibers are accumulated in a felt shape on the entire surface of the aggregate, and the effects of the present invention can be obtained. Absent.

  Examples of the AA cross-sectional view of FIG. 4 (a) are shown in FIG. 6 (a) to FIG. 6 (c). The shape of the protrusion is not particularly limited, but in order to accumulate the fibers in a felt shape on the upper surface of the protrusion and linearly align the fibers between the protrusions, FIG. It is preferable that the protrusions have a substantially rectangular or triangular shape as shown in the vertical cross-sections in FIGS.

  The preferable arrangement and arrangement of the protrusions are the same for the cylindrical accumulation body 4 shown in FIG.

  In the fiber manufacturing method using the electrostatic spraying method, the assembly is usually conductive and grounded. However, in the electrostatic spraying process of the present invention, the grounding is applied to the assembly. Not required. Further, the integrated body may be a non-conductive material such as rubber, plastic, silicon, and the like, which is greatly different from the prior art.

  However, when using the same integrated body, it is preferable to construct a ground because the integration efficiency is increased.

  Next, as step S3, the fibers having directionality accumulated on the surface of the aggregate are removed from the aggregate (separation process). In the electrostatic spraying process, since the felt-like portions and the aligned portions are alternately formed on the aggregate, the fibers can be drawn out after being removed (stripped) from the aggregate.

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated further in detail, this invention is not limited only to these Examples.

[Example 1]
As Example 1 of this invention, the organic fiber was manufactured with the following manufacturing methods.

1) Preparation Step First, polycaprolactone (hereinafter referred to as PCL) (average molecular weight 70 to 100,000) was dissolved in dichloromethane to prepare a solution of 20% by weight as a spinning solution. The PCL concentration is preferably 8% by weight or more and 25% by weight or less, and more preferably 10% by weight or more and 20% by weight or less.

2) Electrostatic spraying process Next, the PCL solution was fiberized using the electrostatic spraying apparatus shown in FIG. 7, and electrostatic spraying was performed using the rubber belt as an integrated body. This electrostatic spraying device will be described below.

  A metal nozzle 12 is connected to the metal holder 11, and the metal holder 11 is fixed at an appropriate position using a stand. A liquid feed pipe 14 is connected to the metal holder 11 on the opposite side of the metal nozzle 12, and a high voltage power supply 13 is connected to the metal holder 11.

  The liquid feeding pipe 14 leads to a container 16 accommodated in another sealed container 15, and the PCL solution is filled in the container 16 as the spinning liquid 17. Furthermore, the sealed container 15 is connected to the compressor 18, and the inside can be brought into a pressurized state.

  When the compressor 18 is turned on, the inside of the sealed container 15 is pressurized, and the spinning liquid 17 in the container 16 is fed to the metal nozzle 12 through the liquid feeding pipe 14.

  Here, a 24G injection needle (length: 15 mm, made of stainless steel) was used as the metal nozzle 12, and the distance between the tip of the metal nozzle 12 and the rubber belt 19 as an integrated body was 15 cm.

  On the other hand, the rubber belt 19 has a width of 12 mm and a thickness of 1 mm, and the surface is provided with protrusions 20 having an isosceles triangle whose vertical cross section is 1 mm in the base and 0.5 mm in height at intervals of 1.3 mm. The arrangement of the protrusions is as shown in FIG. And it is hold | maintained by two rotating shafts (21a and 21b) which are 12 mm in diameter. At this time, the rubber belt 19 is a substantially rectangular parallelepiped ring having a length of 12 mm and a width of 100 mm when viewed from the direction of the extension line of the rotating shaft.

  Further, the metal nozzle 12 and the rotation centers (22a and 22b) of the two rotation shafts (21a and 21b) are adjusted to have the same height.

  The rotating shaft 21a is connected to a motor. By rotating the motor, the rotating shaft 21a also rotates, and the rubber belt 19 can be rotated. The rotating shaft 21b is rotatable and rotates following the rotation of the rotating shaft 21a. Here, the rubber belt 19 was rotated in the direction indicated by the arrow in FIG. 7 (speed 14 cm / sec). In addition, you may rotate in the reverse direction at the same speed.

  Then, a DC voltage of 15 kV was applied to the metal holder 11 by a high voltage power source 13 (manufactured by Pulse Electronics Technology Co., Ltd.). The extrusion pressure of the PCL solution was 0.15 MPa, and the rubber belt 19 was not grounded.

  As a result of electrostatic spraying of the PCL solution while rotating the rubber belt 19, the PCL fibers are accumulated in a felt shape on the protrusions 20, and the PCL fibers are drawn on the part between the protrusions (the flat part 23). Accumulated in an aligned state. A photograph of the surface of the rubber belt 19 at this time is shown in FIG.

3) Separation process Next, the PCL fibers accumulated on the rubber belt 19 were removed using tweezers. The removed PCL fiber is shown in FIG. 9, and an enlarged photograph thereof is shown in FIG.

  As is apparent from FIG. 10, the PCL fiber of this example has felt-like portions and linearly aligned portions connecting the felt-like portions alternately formed. The PCL fiber removed from the aggregate was not torn even if it was stretched in the rotation direction. For this reason, the PCL fiber of a present Example can be extended | stretched after a isolation | separation process.

[Example 2]
As Example 2 of the present invention, a lactic acid / glycolic acid copolymer (hereinafter referred to as PLGA) (average molecular weight 220,000, lactic acid: glycolic acid = 75: 25 (molar ratio)) was dissolved in dichloromethane to obtain 15% by weight. The solution obtained was used as the spinning solution. The PCL concentration is preferably 10% by weight or more and 30% by weight or less, and more preferably 12% by weight or more and 20% by weight or less.

  The same assembly as in Example 1 was used. Also, PLGA fibers were accumulated on the rubber belt in the same manner as in Example 1 except that a DC voltage of 20 kV was applied and the extrusion pressure of the PLGA solution was 0.05 MPa.

  FIG. 11 shows a photograph of the surface of the rubber belt 19 on which PLGA fibers are accumulated, and FIG. 12 shows a photograph of how the PLGA fibers are removed from the rubber belt 19.

  As is apparent from FIG. 11, the PLGA fiber of this example has felt-like portions and linearly connected portions connecting the felt-like portions alternately formed. The PLGA fiber removed from the aggregate was not torn even if it was stretched in the length direction. For this reason, the PLGA fiber of this example can also be subjected to a stretching treatment after the separation step.

  In Example 1 and Example 2, the rubber belt 19 was not grounded, but similar PCL fibers and PLGA fibers could be produced even when grounding was performed. From the viewpoint of improving the integration efficiency, when the same rubber belt 19 is used, it is preferable to construct a ground.

[Example 3]
As Example 3 of the present invention, PCL fibers were produced under the same conditions as in Example 1 except that the conductive belt was applied to the rubber belt 19 used in Example 1 to use an integrated body as a conductive belt. . As a result, the same PCL fiber as in Example 1 was obtained with higher integration efficiency. Similar PCL fibers were obtained with or without grounding the conductive belt.

[Example 4]
As Example 4 of the present invention, a PLGA fiber was produced under the same conditions as in Example 2 except that the conductive belt was applied to the rubber belt 19 used in Example 2 and an integrated body as a conductive belt was used. . As a result, the same PLGA fiber as in Example 2 was obtained with higher integration efficiency. The same PLGA fiber was obtained with or without grounding the conductive belt.

[Example 5]
As Example 5 of the present invention, a rubber belt of the same type as that used in Example 1 was attached to the side surface of a glass cylinder having a diameter of 9 cm and a width of 20 mm, and this was used as an assembly. And the same PCL solution as Example 1 was fiberized using the electrostatic spray apparatus shown in FIG. The parts other than the integrated body are the same as those of the electrostatic spraying apparatus of the first embodiment.

  Here, the metal nozzle 12 and the center 32 of the bottom surface of the cylinder 31 are adjusted to have the same height. Further, a metal seal 34 was wound around the cylinder 31, and a rubber belt 33 was attached thereon. The metal seal 34 was grounded.

  A rotating shaft connected to a motor is attached to the cylinder 31 so as to rotate about the center 32 as a rotation center, and the rubber belt 33 can be rotated by rotating the motor. Here, the rubber belt 33 was rotated in the direction indicated by the arrow in FIG. 13 (rotation speed: 200 rpm). In addition, you may rotate in the reverse direction at the same speed.

  Then, a 20 kV DC voltage was applied to the metal holder 11 by the high voltage power source 13 and electrostatic spraying was performed toward the rubber belt 33. The extrusion pressure of the PCL solution was 0.15 MPa.

  As a result of electrostatic spraying of the PCL solution while rotating the rubber belt 33, the PCL fibers are accumulated in a felt shape on the protrusions 35 of the rubber belt 33, and the PCL is formed between the protrusions and the protrusions (flat portion 36). The fibers were collected in an aligned state. A photograph of the surface of the rubber belt 33 at this time is shown in FIG.

  As apparent from FIG. 14, the PCL fiber of this example has felt-like portions and linearly aligned portions connecting the felt-like portions alternately formed. The PCL fiber removed from the aggregate was not torn off even if it was stretched in the length direction. For this reason, the PCL fiber of this example can also be subjected to a stretching treatment after the separation step.

[Example 6]
As Example 6 of this invention, the electrostatic spray apparatus of Example 5 was performed and the PLGA fiber was manufactured. Electrostatic spraying was performed under the same conditions as in Example 5 except that the spinning solution was the PLGA solution used in Example 2. As a result, the PLGA fibers accumulated on the rubber belt were alternately formed with felt-like portions and linearly aligned portions connecting the felt-like portions. For this reason, the PLGA fiber of this example can also be subjected to a stretching treatment after the separation step.

[Comparative Example 1]
As Comparative Example 1 of the present invention, PCL fibers were produced in the same manner as in Example 1 except that electrostatic spraying was performed from the nozzle position in FIG. A photograph of the rubber belt surface after the electrostatic spraying process is shown in FIG.

  In Comparative Example 1, felt-like PCL fibers were merely accumulated on the protrusions of the rubber belt, and no linearly aligned portions connecting the felt-like portions were formed. Moreover, since it cut | disconnects immediately if it pulls to a length direction after removing from a rubber belt, it was impossible to perform an extending | stretching process.

[Comparative Example 2]
As Comparative Example 2 of the present invention, PLGA fibers were produced in the same manner as in Example 2 except that electrostatic spraying was performed from the nozzle position in FIG.

  However, even in Comparative Example 2, the felt-like PLGA fibers were merely accumulated on the protrusions of the rubber belt, and no linearly aligned portion connecting the felt-like portions was formed. Moreover, since it cut | disconnects immediately if it pulls to a length direction after removing from a rubber belt, it was impossible to perform an extending | stretching process.

[Comparative Example 3]
As Comparative Example 3 of the present invention, the PCL solution was electrostatically sprayed under the same conditions as in Example 5 except that the rubber belt 33 shown in FIG. 13 was removed. That is, the PCL fibers were accumulated on the surface of the metal tape 34 with grounding (no concave protrusion on the surface). A photograph of the surface of the metal tape 34 after the electrostatic spraying process is shown in FIG.

  As apparent from FIG. 16, felt-like PCL fibers were only uniformly accumulated on the metal tape 34. In addition, after removing the fibers from the surface of the aggregate, the fibers are cut as soon as they are pulled in the length direction, so that it was impossible to perform a stretching treatment.

[Comparative Example 4]
As Comparative Example 4 of the present invention, an aluminum rod (5 cm in length) having a diameter of 1 cm was used as an accumulation body, and similarly to Example 5, the PCL solution was electrostatically sprayed from the horizontal direction on the accumulation body. The electrostatic spraying conditions are all the same as in Example 5 except that the assembly (aluminum bar) was rotated at 20000 rpm. In addition, the aluminum rod was grounded.

  An enlarged photograph of the PCL fiber removed from the aluminum bar is shown in FIG. As is clear from FIG. 17, the PCL fiber was completely felt and no directionality was observed. Moreover, since it is cut | disconnected immediately when it pulls, it was impossible to perform an extending | stretching process.

[Comparative Example 5]
As Comparative Example 5 of the present invention, a PLGA fiber was produced using a PLGA solution instead of the PCL solution of Comparative Example 5. The electrostatic spraying conditions are all the same as in Comparative Example 4 except that the spinning solution is the same PLGA solution as in Example 2.

  The PLGA fiber of Comparative Example 5 was completely felt like the PCL fiber of Comparative Example 4, and no directionality was observed. Moreover, since it is cut | disconnected immediately when it pulls, it was impossible to perform an extending | stretching process.

  As described above, according to the method for producing an organic fiber of the present invention, a fine and homogeneous organic fiber that can be stretched can be produced using an electrostatic spray method. Thereby, the organic fiber manufactured by the electrostatic spraying method can be reinforced and used for general purposes.

  The method for producing organic fibers of the present invention is useful as a method for producing organic fibers in the spinning and fiber fields.

It is a schematic flowchart of the manufacturing method of the organic fiber of this invention. It is a figure showing rotation of an accumulation body and a position of a nozzle in the case of using a belt-like (annular) accumulation body. It is a figure showing rotation of an accumulation body and a position of a nozzle in the case of using a cylindrical accumulation body. It is a top view showing the example of the shape of a preferable projection part in a ring-shaped (belt-shaped) accumulation body. It is a top view showing the example of a shape of an undesirable projection part in a ring-shaped (belt-shaped) accumulation body. It is sectional drawing showing the example of a shape of a preferable projection part in a cyclic | annular (belt-shaped) integration | stacking body. It is a figure showing an example of the electrostatic spraying apparatus using a ring-shaped (belt-shaped) accumulation body. 2 is a photograph of the rubber belt surface after the electrostatic spraying process of Example 1. FIG. 2 is a photograph of PCL fibers after the separation step of Example 1. 2 is an enlarged photograph of PCL fibers after the separation step of Example 1. FIG. 4 is a photograph of the rubber belt surface after the electrostatic spraying process of Example 2. FIG. 2 is a photograph of PCL fibers after the separation process of Example 2. It is a figure showing an example of the electrostatic spraying apparatus using a cylindrical accumulation body. 7 is a photograph of the rubber belt surface after the electrostatic spraying process of Example 5. FIG. 3 is a photograph of the rubber belt surface after the electrostatic spraying process of Comparative Example 1. It is a photograph of the metal tape surface after the electrostatic spraying process of the comparative example 3. 6 is a photograph of PCL fibers after the separation step of Comparative Example 4.

Explanation of symbols

1: ring-shaped (belt-shaped) stack 2, 3: rotating shaft 4: cylindrical stack 5a, 5b: bottom 6a: center of bottom 5a 6b: center of bottom 5b 7: rotation center 11: metal holder 12 : Metal nozzle 13: High-voltage power supply 14: Liquid feeding pipe 15: Sealed container 16: Container 17: Spinning liquid 18: Compressor 19: Rubber belt 20: Protruding part 21a, 21b: Rotating shaft 22a: 21a of rotation center 22b: 21b Center of rotation 23: Flat part 31: Cylinder 32: Center of cylindrical bottom 33: Rubber belt 34: Metal seal 35: Projection part 36: Flat part

Claims (5)

A preparation process for preparing a spinning solution in which an organic substance is dissolved in an organic solvent;
An electrostatic spraying step in which a high voltage is applied to the spinning liquid while electrostatically spraying toward the vicinity of the rotation axis of the stack, while rotating the stack having protrusions on the surface;
A method for producing an organic fiber comprising a separation step of removing the fibers accumulated on the surface of the aggregate from the aggregate ,
The said integrated body is a manufacturing method of an organic fiber with which several protrusion part is located in a line so that it may orthogonally cross with respect to a rotation direction .   In the electrostatic spraying process, a high voltage is applied to the spinning liquid while rotating a ring-shaped assembly having a protrusion on the surface and rotated by two rotation shafts, so that the rotation shaft of the ring-shaped accumulation body The manufacturing method of the organic fiber of Claim 1 which sprays electrostatically toward the vicinity.   In the electrostatic spraying process, a high voltage is applied to the spinning liquid while rotating a cylindrical assembly having protrusions on the surface of the side surface about a line connecting the centers of the bottom surfaces of the cylindrical assembly. The method for producing an organic fiber according to claim 1, wherein electrostatic spraying is performed toward the side surface of the aggregate. Method of manufacturing organic fibers according to any one of claims 1 to 3 vertical cross-section is substantially rectangular or triangular of the protrusion.   The manufacturing method of the organic fiber of any one of Claim 1 thru | or 4 which constructs an earth | ground to the said integration body.