JP4511565B2 - Nano-fiber manufacturing equipment - Google Patents

Description

  The present invention relates to a nano-fiber manufacturing apparatus, and more particularly to a technique for suppressing the influence of an air flow when a spinning jet discharged from a spinning port using an electrospinning method is accumulated on a rotating body collector.

  Healthcare fields such as regenerative medicine engineering, wound materials, drug delivery, biotechnology and environmental engineering fields such as affinity membranes and sensors for the purification of biomolecules and contaminated water, polymer batteries, dye-sensitized solar Less than micron (μm) in energy fields such as batteries, polymer membrane fuel cells, etc., or in a wide range of fields such as composite material reinforcement, protection against bioterrorism, and protection / security such as gas clothes A fiber (nanofiber) having a nano-order diameter (for example, several nm to several hundred nm) has attracted attention.

  One technique for producing such nanofibers is the electrospinning method. For example, as disclosed in Patent Document 1, this electrospinning method includes a nozzle that injects a solution of a polymer as a fiber material and a volatile solvent, a flat collector, and a nozzle and a collector. And a high voltage power source for applying a high voltage to the power source.

  In this apparatus, when a solution is pushed out from the spinning nozzle at the tip of the nozzle while a high voltage is applied between the nozzle and the collector, the droplet of the polymer solution at the tip of the spinning nozzle is charged to + (or-), and the different polarity It is attracted by the electrostatic force (Coulomb force) acting along the electric force line toward the collector that is charged (grounded). When the electrostatic force exceeds the surface tension, a spinning jet of polymer solution is continuously jetted toward the collector. At this time, the solvent in the polymer solution is volatilized, and when it reaches the collector, only the polymer fiber is formed, and the nano-fiber is of a nano level. In addition, as a raw material of the nanofiber, not only an organic polymer but also an inorganic material such as a metal oxide or ceramic can be spun into a nanofiber shape by a sol-gel method.

  It is known that a spinning jet ejected from a spinner draws a spiral trajectory due to the influence of the distribution of electric lines of force between the spinneret and the collector while reaching the collector from the spinneret (for example, Non-patent documents 1 and 2). As a result, the nanofibers integrated on the collector are randomly oriented and become non-woven when they are integrated on the collector.

  In order to control this orientation, a cylindrical rotating body collector is used (for example, see Patent Document 2). By using this rotating body collector and winding the spinning jet at a rotational speed faster than the moving speed of the spinning jet, it becomes possible to produce an oriented fiber sample.

Japanese Patent Laying-Open No. 2005-330624 (paragraphs 0036 to 0040, FIG. 3) JP 2005-264386 A (paragraph 0002, FIG. 1) A. El. AL Yarin et al., "Bending instability in electrospinning of nanofibers", Journal of Applied Physics, Vol. 89, Vol. No. 5, March 1, 2001, p. 3018-3026 A. El. AL Yarin et al., "Taylor cone and jetting from liquid droplets in electrospinning of nanofibers", Journal. Journal of Applied Physics, Vol. 90, No. 9, September 1, 2001, p. 4836-4846

As described above, in order to increase the orientation of the nanofiber, it is necessary to increase the rotation speed of the rotator collector. However, even if the number of rotations of the rotator collector is increased, the orientation of the nanofibers integrated on the rotator collector does not increase as expected. As a result of investigating the cause, it has been found that when the rotational speed of the rotating collector is increased, the air flow around the rotating collector increases in proportion to the rotational speed. This air flow causes the spinning jet to travel to the rotor collector surface and disturb the orientation on the collector. In particular, in an apparatus in which the electrospinning apparatus is surrounded by a casing, the air flow in the limited casing becomes irregular, and this influence increases.
Therefore, an object of the present invention is to provide a nano-fiber manufacturing apparatus that can suppress the air flow generated when the rotating body collector rotates and obtain nano-fibers with high orientation.

  In order to solve the above-described problems, the present invention provides a nozzle that injects a solution of a fiber material and a volatile solvent, a rotating body collector, and a high voltage that applies a high voltage between the nozzle and the rotating body collector. In a nano-fiber manufacturing apparatus equipped with a power source, the trajectory of the spinning jet that is discharged from the nozzle toward the rotor collector is disturbed by the air flow on the surface of the rotor collector caused by the rotation of the rotor collector. An air flow restriction means for suppressing this is provided.

  In the nano-fiber manufacturing apparatus, when the rotator collector rotates, the air in contact with the rotator collector surface also rotates with the rotator collector due to the viscosity of the air (as the distance from the surface of the rotator collector increases, the air Will not work). On the other hand, the charged spinning jet ejected from the nozzle travels toward a rotating body collector having a different polarity potential or ground potential. At this time, since the traveling direction of the spinning jet and the traveling direction of the air flow on the surface of the rotating body collector intersect, the trajectory of the spinning jet is disturbed, and the orientation of the nanofiber wound on the rotating body collector is deteriorated. .

  Therefore, as in the present invention, by providing an air flow restricting means, the air flow intersecting with the traveling direction of the spinning jet is restricted, and deterioration of orientation is reduced. Thereby, a highly oriented nanofiber can be obtained.

  The air flow restricting means may be a hood cover that has an opening that exposes the side of the rotating body collector facing the nozzle, and that spatially divides a portion protruding from the opening and other portions. By covering such a hood cover on the rotator collector, the air flow to be rotated with the rotation of the rotator collector is reduced.

  The air flow restricting means may be a blade formed on the side of the rotating body collector so as to protrude from the surface of the rotating body collector.

  When the air that contacts the surface of the rotating body collector rotates together with the rotating body collector, it tends to be blown away from the surface of the rotating body collector in the normal direction by centrifugal force. Pressure state. In an attempt to eliminate the negative pressure state, air flows such that the air on the side of the rotator collector enters the surface of the rotator collector. In order to restrict the air flow, vanes are provided in a protruding state on the side of the rotating body collector. This restricts the air flow replenished on the surface of the rotor collector, reduces the disturbance of the spinning jet trajectory caused by the air flow generated by the rotation of the rotor collector, and the nano fiber wound on the rotor collector The orientation of can be improved.

  According to the present invention, in the nano-fiber manufacturing apparatus, the trajectory of the spinning jet directed to the rotating body collector discharged from the nozzle is disturbed by the air flow on the surface of the rotating body collector generated by the rotation of the rotating body collector. By providing the air flow restricting means for suppressing, a highly oriented nano-fiber can be obtained.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a front view showing an outline of a nanofiber manufacturing apparatus according to the present invention, FIG. 2 is an explanatory view showing a hood cover according to Embodiment 1 of an air flow restricting means of the present invention, and FIG. Front sectional view, (b) is a plan view, (c) is a side sectional view, and FIG. 3 is an explanatory view showing a blade according to Embodiment 2 of the air flow restricting means of the present invention.

  In FIG. 1, the nano-fiber manufacturing apparatus of the present embodiment applies a solution of a polymer as a fiber material and a volatile solvent inside a housing 1 that is sealed and opened by a door (not shown). The syringe 2 that has been put in, the syringe motor 3 that pushes out the solution of the raw material and the solvent in the syringe 2, the flexible solution supply tube 4, the nozzle 5 that has the spinning port 5 a, and the rotary shaft 6 a are driven to rotate. And a high voltage cable 7 for connecting a conductive part of the nozzle 5 and an output terminal of a high voltage power source (not shown).

  The syringe 2 is detachably fixed to the syringe fixing base 8, and the push plate 10 that presses the plunger that pushes out the solution in the syringe 2 is driven by a screw shaft 9 that is rotationally driven by the syringe motor 3.

  The nozzle 5 is mounted in a conductive state on a mounting base 11 made of a conductor, and a high voltage can be applied to the nozzle 5 by connecting the high voltage cable 7 to the mounting base 11 with a connector. The attachment base 11 is attached to a base holder 12, and the base holder 12 is movably installed on the horizontal slide rail 13 in an electrically insulated state. The base holder 12 is driven to move horizontally along the horizontal slide rail 13 by a horizontal drive device (not shown).

  The rotating body collector 6 is supported by a base 14 having a bearing that rotatably receives the rotating shaft 6a, and is connected to an output shaft 16 of a drive motor (not shown) via a coupling 15. The rotating body collector 6 is connected to the ground via a bearing or the like, and a high voltage is applied between the rotating body collector 6 and the nozzle 5.

  In the figure, 17 is a nozzle cleaner for cleaning clogging of the spinning port 5a of the nozzle 5 at the start of spinning, 18 is a support shaft for supporting the horizontal slide rail 13 so as to be movable up and down, and 19 is a horizontal slide rail. A 30-degree trapezoidal screw for driving up and down, 20 is a power on / off switch, 21 is a primary lamp for indicating that a power cable is connected, and 22 is lit when the power on / off switch 19 is turned on. Power-on lamp, 23 is a numeric keypad and operation keys for inputting various settings and operation programs, 24 is a display for displaying setting contents and operation status, 25 is a power button, 26 is a reset key, and 27 is all operations in an emergency. An emergency stop button 28 for stopping is an exhaust pipe for purifying the air in the housing 1 and exhausting it outside.

  In the present embodiment, the solution supply tube 4 flexibly connects the nozzle 5 attached to the attachment base 11 moving in the horizontal direction and the syringe 2 fixed to the syringe fixing base 8. However, the solution supply tube 4 can be omitted by coupling the syringe 2 directly to the nozzle 5. In this case, a power source such as an air pump that presses the plunger of the syringe 2 is fixed to the housing 1, and the air pump that is the power source and the plunger of the syringe 2 are connected by an air tube or the like. It can be configured. By doing so, it is possible to prevent the solution staying in the solution supply tube 4 from being wasted or needing internal cleaning.

Next, operation | movement of this nano fiber manufacturing apparatus is demonstrated.
First, the nozzle 5 is moved to a predetermined position on the rotator collector 6, the rotator collector 6 is rotated at a predetermined rotation number, the syringe motor 3 is driven, and the polymer solution in the syringe 2 is supplied to the nozzle 5. . In a state where a high voltage is not applied between the nozzle 5 and the rotating body collector 6, the polymer solution remains at the surface tension at the tip of the spinning port 5 a at the tip of the nozzle 5. When a high voltage of, for example, several kV to 30 kV is applied between the spinneret 5a and the rotary collector 6, the polymer solution droplet at the tip of the spinneret 5a is charged to + and charged to a different polarity (or ground potential). It is attracted by the electrostatic force toward the rotating collector 6 that is rotating. When the electrostatic force exceeds the surface tension, a spinning jet of the polymer solution is continuously jetted toward the rotating body collector 6.

  The tip of the spinning jet is continuously wound up by the rotating body collector 6. At this time, by reciprocating the nozzle 5 in the longitudinal direction of the rotating shaft 6a of the rotating body collector 6, the nano-fiber can be wound on the rotating body collector 6 within a predetermined length range.

Next, an embodiment of the air flow restriction means of the present invention will be described.
As shown in FIG. 2, the hood cover 30 according to the first embodiment of the air flow restricting unit is attached to the base 14 of the rotating body collector 6, and the side facing the nozzle 5 of the rotating body collector 6 is exposed. An opening 30a is formed, and a portion exposed from the opening 30a and other portions are spatially partitioned. As a result, when the rotator collector 6 rotates, the amount of air around the rotator collector 6 is reduced in the spinning side region below the nozzle 5, and the disorder of the orientation of the nano-fiber is reduced.

  As shown in FIG. 3, the blade 31 according to the second embodiment of the air flow restricting unit is formed on the side of the rotating body collector 6 so as to protrude from the surface of the rotating body collector 6. The blades 31 not only prevent air flowing from the side of the rotator collector 6 to the surface of the rotator collector 6 but also function to generate an airflow that flows from the surface to the side.

  As described above, when the air in contact with the surface of the rotating body collector 6 rotates together with the rotating body collector 6, the air tends to be blown in the normal direction from the surface of the rotating body collector 6 by centrifugal force. The air density on the surface becomes small, and a negative pressure state occurs. In an attempt to eliminate the negative pressure state, air flows so that the air on the side of the rotator collector 6 enters the surface of the rotator collector 6. In order to restrict the air flow, the blade 31 is provided in a protruding state on the side of the rotating body collector 6. As a result, the air flow replenished on the surface of the rotator collector 6 is limited, the disturbance of the spinning jet trajectory due to the air flow generated by the rotation of the rotator collector 6 is reduced, and the air is wound on the rotator collector 6. The orientation of the nanofiber can be increased.

  In the above embodiment, the example in which the nano-fiber manufacturing apparatus is surrounded by the casing 1 has been described. However, the present invention is also applied to an open-structure nano-fiber manufacturing apparatus that is not surrounded by the casing 1. be able to.

  According to the present invention, the amount of wind generated on the surface of the rotating body collector 6 (spinning jet adhering portion) can be reduced. As a result, the spinning jet rotates at a high speed without impeding the progress of the spinning jet 6 to the rotating body collector. Winding by the rotating body collector 6 becomes possible.

  According to the experimental results, it was possible to produce an oriented fiber sample having an area of about A3 size. Depending on the application, an oriented fiber sample is required, and therefore, the application of the nanofiber can be expanded and development can be promoted by this technology.

  The present invention relates to a field of healthcare, biotechnology, and environmental engineering as a nano-fiber manufacturing apparatus that can suppress a flow of air generated when a rotating body collector rotates and obtain highly oriented nano-fibers. It can be used in a wide range of fields such as the energy field or the field of protection and security.

It is a front view which shows the outline | summary of the nanofiber manufacturing apparatus which concerns on this invention. It is explanatory drawing which shows the hood cover which concerns on Embodiment 1 of the air flow restriction | limiting means of this invention, (a) is a front sectional view, (b) is a top view, (c) is a sectional side view. It is explanatory drawing which shows the blade | wing which concerns on Embodiment 2 of the air flow restriction | limiting means of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Case 2 Syringe 3 Syringe motor 4 Solution supply tube 5 Nozzle 5a Spinning port 6 Rotating body collector 6a Rotating shaft 7 High pressure cable 8 Syringe fixing stand 9 Screw shaft 10 Push plate 11 Mounting base 12 Base holder 13 Horizontal slide rail 14 Base Table 15 Coupling 16 Output shaft 17 Nozzle cleaner 18 Support shaft 19 30 degree trapezoidal screw 20 Power on / off switch 21 Primary lamp 22 Power on lamp 23 Numeric keypad and operation key 24 Display 25 Power button 26 Reset key 27 Emergency stop button 28 Exhaust cylinder 30 Hood cover 30a Opening 31 Feather

Claims (3)

In a nano-fiber manufacturing apparatus comprising a nozzle that injects a solution of a fiber material and a volatile solvent, a rotating body collector, and a high-voltage power source that applies a high voltage between the nozzle and the rotating body collector ,
An air flow restricting means is provided for restricting the air flow on the surface of the rotating body collector caused by the rotation of the rotating body collector in the direction intersecting with the traveling direction of the spinning jet toward the rotating body collector. Fiber manufacturing equipment.   The air flow restricting means is a hood cover that has an opening that exposes a side facing the nozzle of the rotating body collector, and spatially partitions a portion protruding from the opening and other portions. The nano-fiber manufacturing apparatus as described.   2. The nano-fiber manufacturing apparatus according to claim 1, wherein the air flow restricting means is a blade formed on a side portion of the rotating body collector so as to protrude from a surface of the rotating body collector.

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