JP4523013B2 - Nonwoven fabric manufacturing equipment - Google Patents

Description

  The present invention relates to a nonwoven fabric production apparatus for depositing nanofibers made of a polymer substance to produce a nonwoven fabric.

  An electrospinning (charge-induced spinning) method is known as a method for producing a filamentous material (hereinafter referred to as “nanofiber”) made of a polymer material and having a submicron-scale diameter.

  This electrospinning method is a method in which a polymer solution in which a polymer substance is dispersed in a solvent is ejected (outflowed) from a needle-like nozzle to which a high voltage is applied to a collector (collecting electrode) toward the collector. This is a method for obtaining nanofibers. More specifically, the charged polymer solution is injected into the space by setting the injection nozzle at a high voltage, and the charge density of the polymer solution flying in the space increases as the solvent evaporates. A phenomenon (electrostatic explosion) in which the polymer solution is explosively stretched linearly occurs when the repulsive Coulomb force generated in the polymer solution exceeds the surface tension of the polymer solution. This electrostatic explosion occurs one after another in the space, so that nanofibers made of a polymer having a submicron diameter are manufactured.

  In addition, by depositing nanofibers manufactured by the above-mentioned method on a substrate, a three-dimensional thin film having a three-dimensional network can be obtained, and by forming a thicker film, a high thickness having a submicron network can be obtained. A porous web (nonwoven fabric) can be produced.

  The web manufactured by employing the electrospinning method as described above has a high porosity composed of nano-order pores and has a large surface area as a whole, so that it is a filter, a separator for a battery, and a polymer electrolyte membrane for a fuel cell. It is expected to obtain a high effect when applied to electrodes and electrodes.

Conventionally, as a method for producing a large amount of nanofibers to produce a practical web made of nanofibers, an apparatus for producing a web by arranging a plurality of nozzles in parallel and depositing a large amount of nanofibers has been proposed. (For example, refer to Patent Document 1).
JP 2002-201559 A

Conventionally, the following knowledge has been obtained through experiments and research.
That is, in order to improve the uniformity of the deposition direction of nanofibers deposited on the collector and the spatial uniformity of the deposition amount, a nozzle for injecting a polymer solution and a collector for collecting the manufactured nanofibers It is desirable to make the distance of as short as possible. In addition, the higher the voltage between the nozzle and the collector, the greater the number of occurrences of not only the primary explosion but also the high-order electrostatic explosion after the secondary explosion, and the diameter of the nanofiber to be manufactured becomes finer. become.

  On the other hand, as the distance between the nozzle and the collector is increased, the amount of evaporation of the solvent is increased, and the number of high-order electrostatic explosions is increased. Moreover, the abnormal discharge which generate | occur | produces between a nozzle and a collector can be suppressed, so that the voltage between a nozzle and a collector is low, and the distance between a nozzle and a collector is lengthened.

  When manufacturing a nonwoven fabric with nanofibers, the distance between the nozzle and the collector and the voltage are determined as a compromise in view of the above conflicting viewpoints.

  However, when a plurality of nozzles are arranged as described in Patent Document 1, a large amount of nanofibers are manufactured, and a nonwoven fabric is to be obtained, the distance and voltage between the nozzle and the collector that have been determined in the past are used. The present inventors have found a situation in which it is difficult to ensure the uniformity of the deposition direction and the spatial uniformity of the deposition amount.

  In view of the above problems, the inventors of the present application have conducted intensive studies and experiments, and as shown in FIG. 8, the geometric relationship between the lines of electric force 4 generated from the nozzle 1 toward the collector 2 and the surface of the collector 2. In particular, it has been thought that the shape of the edge portion 5 of the collector 2 is related to the uniformity of the deposition direction of the nanofibers, the spatial uniformity of the deposition amount, etc. Etc. In FIG. 8, the sheet 3 is disposed on the collector 2.

  The present invention has been made in view of the above problems, and in manufacturing a nonwoven fabric made of nanofibers, a nonwoven fabric manufacturing apparatus capable of ensuring the uniformity of the volume direction of nanofibers and the spatial uniformity of the deposition amount. For the purpose of provision.

  In order to achieve the above object, the nonwoven fabric manufacturing apparatus according to the present invention is applied with a voltage, an injection means having injection holes for injecting a raw material liquid for producing nanofibers, a voltage different from that of the injection means, A non-woven fabric manufacturing apparatus including a collecting electrode for collecting fibers, wherein the collecting electrode includes a curved surface portion that bends in a direction away from the injection hole at a peripheral portion of a surface of the collection electrode desired from the injection hole. To do.

  Thereby, the edge part of the collection electrode 120 moves away from an injection hole gently, and the sudden change of an electric field can be avoided. Therefore, it is possible to prevent the uneven distribution of electric lines of force and the like, and to ensure the uniformity of the deposition direction of the nanofibers and the spatial uniformity of the deposition amount.

Furthermore, you may provide the said injection hole in the curvature radius direction of the curved-surface part of the said collection electrode.
Thereby, it becomes possible to improve the deposition performance of nanofibers.

  Further, the radius of curvature of the curved surface portion may be not less than one quarter and not more than 10 times the distance between the injection hole closest to the curved surface portion and the curved surface portion among the injection holes facing in the radius of curvature direction. desirable.

Thereby, an effective curved surface portion can be realized.
Furthermore, the collecting electrode is disposed on the injection hole side of the collecting electrode, and includes a depositing means for holding the manufactured nanofibers in a deposited state, and a moving means for moving the depositing means in a predetermined direction. Further, it may have a cylindrical shape whose axial direction is a direction intersecting the moving direction of the deposition means.

  Thereby, it becomes possible to manufacture a long nonwoven fabric, and to ensure the uniformity of the thickness of the manufactured nonwoven fabric in the width direction.

  Furthermore, a plurality of the injection holes arranged so as to spread perpendicularly to the moving direction of the deposition means, and the adjacent injection holes may be arranged shifted from each other in the moving direction.

  Thereby, the disturbance of the electric lines of force due to the influence of the injection holes can be prevented as much as possible, and the uniformity in the width direction of the nonwoven fabric produced from the injection holes can be ensured.

  According to the present invention, the uniformity of the nanofiber in the volume direction and the spatial uniformity of the deposition amount can be ensured, and a homogeneous nonwoven fabric can be produced. Furthermore, even if a nonwoven fabric is manufactured with high efficiency, it becomes possible to ensure the uniformity of the nonwoven fabric.

Next, an embodiment of the nonwoven fabric manufacturing apparatus according to the present invention will be described.
FIG. 1 is a perspective view schematically showing a non-woven fabric manufacturing apparatus according to the present invention.

  As shown in the figure, the nonwoven fabric manufacturing apparatus 100 includes a jetting unit 110, a collecting electrode 120, and a sheet 160 as a depositing unit. In addition, since the raw material liquid to be injected and the nanofiber being manufactured cannot be clearly distinguished, the reference numeral 200 is assigned to each, and the manufactured nonwoven fabric is assigned 210.

  The injection means 110 is an apparatus having an injection hole for injecting (flowing out) a raw material liquid for producing nanofibers, and is connected to a power source 150a and maintained at a predetermined potential. A pipe 111 connected to a tank (not shown) for storing the raw material liquid is connected to the injection means 110 so that the raw material liquid is supplied at a predetermined pressure.

  The collecting electrode 120 is connected to the power source 150b so that a predetermined voltage is applied to the ejection unit 110, and is a device for collecting the manufactured nanofibers. In addition, there are various modes of the ejection unit 110 and the collecting electrode 120, and there are various combinations of these modes. In FIG. 1, the ejection unit 110 and the collection electrode 120 are symbolically shown by a one-dot chain line, and specific embodiments thereof will be described later.

  The sheet 160 is a member on which the nanofibers 200 manufactured in the space are to be deposited, and is a thin and flexible long sheet made of a material that can be easily separated from the deposited nanofibers 200. . The sheet 160 is supplied in a state of being wound in a roll shape, and slowly moves in the direction of the arrow in the drawing by the moving means 170 through the portion where the nanofibers 200 are deposited. And it rolls around with the nonwoven fabric 210 manufactured on the sheet | seat 160 again in roll shape.

  The moving means 170 is a device capable of feeding the sheet 160 in one direction while maintaining a predetermined tension, and moves the sheet 160 by rotating a roller shown in the drawing by driving a motor (not shown) or the like. Is.

(Specific example 1 of injection means and collecting electrode)
FIG. 2 is a diagram illustrating a specific example of the ejection unit and the collection electrode.

  The figure shows the ejection means 110 larger in order to show the relationship between the ejection means 110 and the collection electrode 120, but in reality the diameter of the collection electrode 120 is several meters, whereas the nozzle The diameter of the tip of 113 is about several millimeters.

  The collecting electrode 120 shown in the figure has a cylindrical shape and can rotate with the movement of the sheet 160 or in synchronization. The collecting electrode 120 has a rounded chamfer at the cylindrical edge portion so that the diameter gradually decreases toward the end surface of the collecting electrode 120.

  The collecting electrode 120 may be not only a perfect circle but also a polygon that can approximate a circle.

  The injection means 110 includes a plurality of nozzles 113 each having an injection hole (not shown) for injecting the raw material liquid at the tip. The nozzles 113 are arranged at equal intervals in a direction perpendicular to the moving direction of the sheet 160 (X direction in the figure, width direction of the sheet 160). The nozzle 113 is arranged on a diagonal line with respect to the Y direction. Therefore, the adjacent nozzles 113 are in a state of being displaced in the Y direction. Further, the nozzle 113 is arranged in a radial direction around the rotation axis so that the raw material liquid 200 can be sprayed toward the rotation axis of the collecting electrode 120. The nozzle 113 at the extreme end in the X direction and the nozzle 113 at the other extreme end (nozzles 113 at both ends in the width direction of the sheet 160) are set so that the distance in the X direction is narrower than the width of the sheet 160. Moreover, it inclines toward the curvature center c of a curved-surface part (refer FIG. 3).

  By disposing the nozzle 113 as described above, the distance between the nozzles 113 can be increased while maintaining the collection electrode 120 and the nozzle 113 at a predetermined distance, and the nano-particles manufactured from the adjacent nozzles 113 can be made. The deposition positions of the fibers 200 on the sheet 160 can be arbitrarily overlapped.

  Therefore, the disturbance of the electric lines of force caused by the nozzles 113 affecting each other is suppressed, the positional deviation of the deposited amount of the nanofibers 200 in the width direction of the sheet 160 is prevented, and the thickness in the width direction of the sheet 160 is prevented. It is possible to produce a uniform nonwoven fabric.

  FIG. 3A is a view in which the ejection means and the collection electrode are viewed from the Y direction, and the collection electrode and the sheet are cut.

  As shown in the figure, both end portions in the X direction of the collecting electrode 120 desired from the nozzle 113 are R-chamfered to form a curved surface portion 122. In other words, the peripheral edge of the collection electrode 120 desired from the nozzle 113 is gradually moved away from the nozzle 113 and reaches the peripheral edge of the collection electrode 120. Therefore, it is possible to avoid a state in which the relationship between the collection electrode 120 to which a predetermined voltage is applied and the nozzle 113 changes suddenly, and virtually violent electric force lines (for example, electric force) from the nozzle 113 to the collection electrode It is possible to create a state in which the local concentration of the line is less likely to occur. This is the same state in the Y direction, and the same effect can be obtained.

  Thereby, when the nanofiber 200 manufactured by jetting the raw material liquid 200 from the nozzle 113 is deposited on the sheet 160, the uniformity of the deposition direction of the nanofiber 200 and the uniformity of the deposition amount can be ensured. By pulling, the nonwoven fabric 210 can be manufactured stably, and the performance of the nonwoven fabric 210 itself can be improved.

  The relationship between the radius of curvature L1 of the surface of the curved surface portion 122 of the collecting electrode 120 and the shortest distance L0 from the tip of the nozzle 113 to the surface of the curved surface portion 122 is preferably L0 × 10 ≧ L1 ≧ L0 / 4. Furthermore, a range of L0 × 5 ≧ L1 ≧ L0 / 2 is preferable. Furthermore, even when the maximum diameter of the collecting electrode 120 is L2, it is desirable that L0 × 10 ≧ L2 ≧ L0 / 4 is satisfied.

  When the curvature radius L1 is larger than 10 times L0, the collection electrode 120 cannot be sufficiently distant from the nozzle 113 unless the width of the collection electrode 120 is made considerably larger than the maximum width in the X direction in which the nozzle 113 is disposed. In this case, if the width of the collecting electrode 120 is set to a certain extent to save space, the edge of the end portion of the collecting electrode 120 can be expected from the nozzle 113 as in the case of the conventional flat plate-shaped collecting electrode. In this portion, the lines of electric force are disturbed, and the deposition state of the nanofiber 200 is deteriorated.

  On the other hand, when the radius of curvature L1 is smaller than a quarter of L0, the collecting electrode 120 is rapidly moved away from the nozzle 113, so that the electric lines of force are likely to be disturbed as in the case of the conventional flat collecting electrode. Therefore, the deposition state of the nanofiber 200 can be deteriorated.

  In the above description, the shape of the curved surface portion 122 is defined by the radius of curvature, but the shape of the curved surface portion 122 is not limited to a circle. In FIG. 5B, if the curved surface has a cross-sectional shape included in the range indicated by the oblique lines, the curved surface portion 122 has an arbitrary curved surface such as an ellipse within the above range.

(Specific example 2 of injection means and collecting electrode)
FIG. 4 is a diagram showing another specific example of the ejection unit and the collection electrode.

  The figure shows the ejection means 110 larger in order to show the relationship between the ejection means 110 and the collection electrode 120, but in reality, the collection electrode 120 is several meters in size, whereas the rotary cylinder 114 is larger. The diameter is about several centimeters.

  The collecting electrode 120 shown in the figure has a shape with a smooth curved surface such that the peripheral edge is away from the injection hole 112 over the entire circumference of the flat plate.

  The collecting electrode 120 is fixedly arranged with respect to the nonwoven fabric manufacturing apparatus 100 and is in a rubbing state with the moving sheet 160.

  With such a collecting electrode 120, it is not necessary to rotate the collecting electrode 120. Therefore, the potential of the collecting electrode 120 can be easily stabilized, and the size can be easily reduced.

  The injection means 110 includes a cylindrical rotary cylinder 114 in which a number of nozzles 113 including a large number of injection holes 112 are provided on the peripheral wall.

FIG. 5A is a perspective view of the ejecting means, and FIG. 5B is a cross-sectional view.
As shown in the figure, the injection means 110 is a device that injects (flows out) the raw material liquid by centrifugal force, and includes a rotary cylinder 114, a tank 115 that stores the raw material liquid 200, a tank 115, and a rotary cylinder 114. A pipe 111 to be connected, a shaft 301 serving as a rotating shaft that also serves as the pipe 111, a rotating body support 312, a bearing 310, gears 307 and 308, and a rotating means 306 are provided.

  The rotary cylinder 114 is rotatably supported with respect to the rotating body support 312 via a shaft 311 and a bearing 310. Further, it is maintained at a predetermined potential by the power source 150a via the brush 315. The rotary cylinder 114 is connected to a rotating means 306 attached to the rotating body support 312 via gears 307 and 308 and is rotated by a driving force applied from the rotating means 306.

  Further, a pipe for distributing the raw material liquid 200 is connected to one of the shafts 301, and the raw material liquid 200 supplied from the tank 115 is pumped by the pump 117, and passes through a hole drilled in the peripheral wall of the shaft 301. The raw material liquid 200 is supplied inside 114. Thus, the raw material liquid 200 is evenly supplied in the axial direction by injecting the raw material liquid 200 in an equal amount by supplying the raw material liquid to the rotary cylinder 114 through the hole provided in the peripheral wall of the shaft 301. Be able to.

  If the above injection means 110 is employ | adopted, a comparatively large amount of nanofiber 200 can be manufactured at once, and it will become possible to manufacture the nonwoven fabric 210 efficiently.

(Specific example 3 of injection means and collecting electrode)
FIG. 6 is a perspective view showing another specific example of the ejection unit and the collection electrode.

FIG. 7 is a front view showing another specific example of the ejection means and the collection electrode.
The figure shows the ejecting means 110 larger in order to show the relationship between the ejecting means 110 and the collecting electrode 120, but in reality, the diameter of the collecting electrode 120 is several meters, whereas The diameter of the mold cylinder 116 is about several centimeters.

  The collecting electrode 120 shown in the figure is a part of a spherical surface, and is arranged in a fixed manner with respect to the nonwoven fabric manufacturing apparatus 100. Therefore, the moving sheet 160 is in a rubbing state.

  With such a collecting electrode 120, it is not necessary to rotate the collecting electrode 120, so that the potential of the collecting electrode 120 can be easily stabilized, and the size can be easily reduced.

  The injection means 110 includes a cylindrical vertical cylinder 116 in which a number of nozzles 113 including a large number of injection holes 112 are provided on the peripheral wall.

  The vertical cylinder 116 is rotationally driven by a motor 118 and injects the raw material liquid 200 in the horizontal direction by centrifugal force.

  According to this vertical cylinder 116, a large amount of nanofibers 200 can be manufactured in a relatively wide range even with a cylinder 116 having a small diameter with respect to the collecting electrode 120.

  Further, since the collecting electrode 120 can be made larger with respect to the small vertical cylinder 116, the edge of the collecting electrode 120 desired from the vertical cylinder 116 can be set far away, and the collecting electrode 120 can be set at the edge of the collecting electrode 120. The effect of the curved surface portion provided can be further enhanced, and the deposition performance of the nanofiber 200 can be improved. Further, since the vertical cylinder 116 is small and has sufficient nanofiber 200 manufacturing capability, it is possible to ensure high productivity while maintaining the deposition performance of the nanofiber 200.

  Further, the manufacturing range of the nanofiber 200 can be adjusted by the rotation speed of the vertical cylinder 116, and the deposition performance of the nanofiber 200 can be further improved by changing the rotation speed over time. It is.

  With the above configuration, the spatial positional relationship between the vertical cylinder 116 and the collecting electrode 120 becomes equivalent on the XY plane, and uneven distribution of electric lines of force can be easily avoided. Therefore, it is possible to manufacture the uniform nonwoven fabric 210 while ensuring the spatial uniformity of the deposited state of the nanofibers 200 on the sheet 160.

  The shape of the collecting electrode 120 is not limited to the above, and may be the collecting electrode 120 having an arbitrary curved surface such as an elliptical sphere. Of course, a plane may be provided.

  INDUSTRIAL APPLICABILITY The present invention can be used for a nonwoven fabric manufacturing apparatus that can be applied to a filter using microporosity or a catalyst support using a wide surface area.

It is a perspective view showing roughly the nonwoven fabric manufacturing device concerning the present invention. It is a figure which shows the specific example of an injection means and a collection electrode. (a) is the figure which shows the injection means and the collection electrode from the Y direction, and shows the cut | disconnection electrode and a sheet | seat, and (b) is a conceptual diagram which shows the allowable range of the shape of a curved surface. It is a figure which shows the other specific example of an injection means and a collection electrode. (a) is a perspective view of an injection means, (b) is sectional drawing. It is a perspective view which shows the other specific example of an injection means and a collection electrode. FIG. 7 is a front view showing another specific example of the ejection means and the collection electrode. It is a figure which shows the relationship between the conventional nozzle and a collector.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Nonwoven fabric manufacturing apparatus 110 Injection means 111 Pipe 112 Injection hole 113 Nozzle 114 Rotary cylinder 115 Tank 116 Vertical cylinder 117 Pump 118 Motor 120 Collection electrode 122 Curved surface 150 Power supply 150a Power supply 150b Power supply 160 Sheet 170 Movement means 200 Nanofiber 200 Raw material liquid 210 Non-woven fabric 301 Shaft 306 Rotating means 307 Gear 308 Gear 310 Bearing 311 Shaft 312 Rotating body support 315 Brush

Claims (5)

A non-woven fabric manufacturing apparatus provided with a collecting electrode that collects nanofibers by applying a voltage and applying spraying means for spraying a raw material liquid for producing nanofibers, and applying a voltage different from the spraying means,
The said collection electrode is a nonwoven fabric manufacturing apparatus provided with the curved part bent in the direction away from the said injection hole in the peripheral part of the surface of the said collection electrode desired from the said injection hole.   The nonwoven fabric manufacturing apparatus according to claim 1, wherein the ejection unit includes the ejection holes in a curvature radius direction of the curved surface portion of the collecting electrode.   The radius of curvature of the curved surface portion is not less than ¼ and not more than 10 times the distance between the injection hole closest to the curved surface portion and the curved surface portion among the injection holes facing in the radius of curvature direction. The nonwoven fabric manufacturing apparatus as described. further,
A deposition means disposed on the injection hole side of the collecting electrode and holding the manufactured nanofibers in a deposited state;
Moving means for moving the deposition means in a predetermined direction,
The nonwoven fabric manufacturing apparatus according to claim 1, wherein the collecting electrode has a cylindrical shape whose axial direction is a direction intersecting a moving direction of the deposition unit. further,
The nonwoven fabric manufacturing apparatus according to claim 4, wherein a plurality of the injection holes are provided so as to spread in a direction perpendicular to the moving direction of the deposition means, and adjacent injection holes are arranged to be shifted from each other in the moving direction. .

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