Electrostatic ejection device

Abstract

To provide an electrostatic ejection device which can enhance spinning ability and can be used even in a low voltage state.SOLUTION: There is provided an electrostatic ejection device for applying a voltage to liquid for ejecting the liquid, the electrostatic ejection device comprises: an electrode for applying a voltage to the liquid; and a nozzle having an ejection hole for ejecting the liquid to an object. The nozzle has: a nozzle body which becomes in a tapered shape toward an ejection direction of the liquid; and a protrusion part protruded toward the ejection direction side from a tip end of the nozzle body, and having an ejection hole. A maximum outer diameter of the protrusion part is equal to or less than an outer diameter of a connection part connecting the protrusion part and the nozzle body, and an outer peripheral end face on the ejection hole side of the protrusion part is formed in an R surface shape.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to an electrostatic spraying device.

Background Art

[0002] Conventionally, an electrostatic spraying device that sprays a liquid by electrostatic force is known. For example, in Patent Document 1, inside a housing sized to be held by a user's hand, there are provided a motor, a high-voltage generator, a battery, etc., and a liquid composition electrostatically charged (electrostatically charged) by a high voltage from the high-voltage generator is sprayed from a nozzle toward an object. An electrostatic spraying device is described.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, since the electrostatic spraying device of Patent Document 1 is used at a high voltage, when used at a low voltage, the electric field weakens, and the liquid ejected from the nozzle may disperse before reaching the object, and there is a risk that the spraying range will widen. At the same time, there is a risk that the spraying amount and the spinning possible range will be limited. Therefore, there is room for improvement in terms of suppressing the spread of the ejected liquid, improving the spinnability, and being able to be used even at a low voltage.

[0005] The present invention relates to an electrostatic spraying device that can improve spinnability and can be used even at a low voltage.

Means for Solving the Problems

[0006] The present invention relates to an electrostatic spraying device that applies a voltage to a liquid to eject the liquid, comprising an electrode for applying a voltage to the liquid and a nozzle having a spray hole for ejecting the liquid toward an object, wherein the nozzle comprises a nozzle body that tapers toward the direction of liquid ejection and a protruding portion that protrudes from the tip of the nozzle body toward the ejection direction and has the spray hole, the maximum outer diameter of the protruding portion is less than or equal to the outer diameter of the connection portion between the protruding portion and the nozzle body, and the outer peripheral end face of the protruding portion toward the spray hole is formed in an R-shape. [Effects of the Invention]

[0007] The electrostatic ejection device according to the present invention can improve spinnability and can also be used at low voltages. [Brief explanation of the drawing]

[0008] [Figure 1] This is a perspective view showing the electrostatic spray device according to this embodiment. [Figure 2] This is an exploded perspective view showing the cartridge according to this embodiment detached from the electrostatic spraying body. [Figure 3] This is a cross-sectional view showing the ejection section of the cartridge according to this embodiment. [Figure 4] This is a schematic cross-sectional view showing the nozzle according to this embodiment. [Figure 5] This is an enlarged cross-sectional view showing the protruding portion of the nozzle according to this embodiment. [Figure 6] This is a block diagram showing the internal configuration of the housing of the electrostatic jet device according to this embodiment. [Modes for carrying out the invention]

[0009] Hereinafter, preferred embodiments for carrying out the present invention will be described with reference to the drawings. Note that the following embodiments are not intended to limit the invention as described in each claim, and not all combinations of features described in the embodiments are necessarily essential to the solution of the invention. Furthermore, the drawings are schematic diagrams with appropriate emphasis, omissions, and adjustments of proportions to illustrate the present invention, and may differ from the actual shapes, positions, and proportions.

[0010] First, the electrostatic spray device 10 according to this embodiment will be described with reference to Figures 1 to 6. The electrostatic spray device 10 according to this embodiment is an electrostatic spray device 10 that sprays liquid by applying a voltage to the liquid, and generally comprises an electrode for applying a voltage to the liquid and a nozzle 123 having a spray hole 123a for spraying the liquid toward an object. The nozzle 123 comprises a nozzle body 125 that tapers toward the direction of liquid spraying and a protruding portion 129 that protrudes toward the spraying direction from the tip of the nozzle body 125 and has a spray hole 123a. The maximum outer diameter of the protruding portion 129 is less than or equal to the outer diameter of the connection portion 127 between the protruding portion 129 and the nozzle body 125, and the outer peripheral end face 129a on the spray hole side of the protruding portion 129 is formed in an R-shape.

[0011] In this specification, "direction of liquid ejection" refers to the direction along the central axis of the ejection hole 123a of the nozzle 123.

[0012] [Overall configuration and operation overview of the electrostatic spray device] As shown in Figures 1 and 2, the electrostatic spray device 10 according to this embodiment comprises a cartridge 100 for containing liquid and an electrostatic spray body 200 from which the cartridge 100 can be inserted and removed. The electrostatic spray device 10 according to this embodiment may also be configured to include a cap that is attached to the cartridge 100. In this embodiment, for the sake of explanation, the direction in which the cartridge 100 is inserted into the electrostatic spray body 200 will be described as downward, and the direction in which the cartridge 100 is removed from the electrostatic spray body 200 will be described as upward. However, the vertical direction referred to here is not necessarily the vertical direction in actual use.

[0013] The electrostatic spray device 10 according to this embodiment is a handheld device shaped and sized to be held in the user's hand, and sprays a liquid (liquid composition) toward an object using the electrostatic spray method. The electrostatic spray method is a method in which a voltage (for example, several kV to tens of kV) is applied to a liquid (for example, a solution of a polymer compound dissolved in a volatile solvent) to electrostatically charge the liquid (electrostatically charge it), and the liquid is sprayed toward the object by the electrostatic force based on the potential difference between the charged liquid and the object. The liquid sprayed by the electrostatic spray method is sent toward the object in the form of a mist or an extremely fine thread. The sprayed liquid can form a film on the surface of the object as the volatile solvent dries after being sprayed toward the object and after adhering to the object. When spraying the liquid toward the human body, for example, the skin becomes the deposition surface. The electrostatic spray device 10 according to this embodiment is an electrostatic spray device that sprays a solution containing raw materials for electrospinning, i.e., spinning liquid, toward an object.

[0014] If, for example, a solution containing (a) a volatile substance, (b) a water-insoluble polymer for fiber formation, and (c) water is used as the liquid, the user can hold the electrostatic spraying device 10 in their hand and spray this liquid toward their skin to form a film on the surface (deposit surface) of the person's (user's) skin, which is the target surface. The film is preferably a deposit containing fibers mainly composed of component (b). Details of the liquid will be described later.

[0015] [Cartridge Configuration] The cartridge 100 is a disposable container that is replaceably attached to a device to which liquid is supplied, and its use is not particularly limited, but in this embodiment it is a cartridge for an electrostatic spray device used in an electrostatic spray device. Specifically, as shown in Figures 2 and 3, the cartridge 100 has a cylindrical liquid storage section 110 capable of containing liquid, and a spray section 120 positioned above the liquid storage section 110 and spraying the liquid inside the liquid storage section 110. The liquid storage section 110 and the spray section 120 may be formed integrally or may be made of separate components.

[0016] As shown in FIG. 2, the liquid storage unit 110 is disposed below the ejection unit 120 and has a cylindrical shape including a first cylindrical member 111 that can be connected to the ejection unit 120 and a second cylindrical member 112 that is disposed below the first cylindrical member 111 and can be connected to the first cylindrical member 111. Further, the liquid storage unit 110 is configured such that the axis of the liquid storage unit 110 (the axis along the vertical direction) is orthogonal to the axis of the nozzle 123. The first cylindrical member 111 is a cylindrical container configured to store a liquid composition. The first cylindrical member 111 is made of a rigid member and is configured to prevent the liquid composition from leaking from the first cylindrical member 111 due to reasons such as breakage of the container or leakage of the liquid from the container. Here, the rigid member may be a material having a rigidity such that the first cylindrical member 111 does not break during use and transportation of the electrostatic ejection device 10, and for example, a plastic material or the like can be adopted.

[0017] The second cylindrical member 112 is a plastic cylindrical container and has a smaller diameter than the first cylindrical member 111. Further, the second cylindrical member 112 is configured to rotate with respect to the first cylindrical member 111 by the rotational force generated by driving the drive unit 246 described later. Inside the second cylindrical member 112, as shown in FIG. 3, a piston rod 112a and a piston 112b provided at the end of the piston rod 112a on the ejection unit 120 side are disposed.

[0018] The piston rod 112a is configured to be axially movable forward and backward by the rotation of the second cylinder member 112, and is configured to push up the piston 112b toward the ejection part 120. Specifically, threads (not shown) that can be screwed together are respectively formed on the inner surface of the second cylinder member 112 and the outer surface of the piston rod 112a, and the piston rod 112a is configured to be screwed forward toward the ejection part 120 by the rotation of the second cylinder member 112. The piston 112b is configured to be axially movable forward and backward (in the direction along the liquid storage part 110) by the piston rod 112a, and is configured to push out the liquid composition to the ejection part 120 by being pushed up toward the ejection part 120 by the piston rod 112a.

[0019] As shown in FIG. 3, the ejection part 120 has a mounting body 121, a connecting body 122, a nozzle 123, and a shut-off pin 124. In this embodiment, a part of the mounting body 121 is formed of a conductive resin (for example, a resin containing carbon). Note that the "conductive resin" includes conductive materials such as metals and carbon, and also refers to a resin having low electrical resistance and being easy for electricity to flow through. For example, it refers to a resin having a volume resistivity of 10 -2 Ωm or less. As the resin, for example, resins having solvent resistance to solvents such as ethanol, such as PP (polypropylene) resin, PET (polyethylene terephthalate), PE (polyethylene) resin, and POM (polyacetal) resin, can be adopted. Note that all of the mounting body 121, or the mounting body 121 and the connecting body 122 may be formed of a conductive resin.

[0020] The mounting body 121 has a flow path 121a and a small electrode 121b. The flow path 121a is a passage through which the liquid composition flows. The small electrode 121b is configured to electrostatically charge the liquid composition flowing in the flow path. The connector 122 is connected to the liquid storage section 110 and communicates with the inside of the liquid storage section 110, and is configured to guide the liquid composition in the liquid storage section 110 to the flow path 121a of the mounting body 121. The nozzle 123 is connected to the mounting body 121 and has a ejection hole 123a at its tip, as well as a linear nozzle flow path connecting the ejection hole 123a to the flow path 121a of the mounting body 121. The nozzle 123 is configured to eject the liquid composition in the liquid storage section 110 through the ejection hole 123a. In this embodiment, the nozzle 123 is configured as a separate component from the mounting body 121, but the nozzle 123 and the mounting body 121 may be integrally configured.

[0021] The shut-off pin 124 is configured to move back and forth along the axial direction of the nozzle 123, and is configured to open and close the ejection hole 123a of the nozzle 123. The "axial direction of the nozzle 123" refers to the axis that passes through the center of the ejection hole 123a of the nozzle 123 and is aligned with the direction of liquid ejection. Specifically, the shut-off pin 124 is connected to an operating unit 242, which will be described later, at the end of the nozzle 123 opposite to the tip. When the operating unit 242 is operated, the shut-off pin 124 retracts relative to the tip of the nozzle 123, opening the ejection hole 123a of the nozzle 123. When the operation of the operating unit 242 is finished, the shut-off pin 124 moves towards the tip of the nozzle 123, sealing the ejection hole 123a of the nozzle 123. Furthermore, the shut-off pin 124 may be disposable, similar to the cartridge 100, or the cartridge 100 may be disposable while the shut-off pin 124 can be reused.

[0022] The total amount of liquid ejected per unit time (discharge rate) from the nozzle 123 is preferably 0.01 ml / min or more, more preferably 0.02 ml / min or more, and even more preferably 0.04 ml / min or more, from the viewpoint of improving the discharge rate and quickly spraying a predetermined amount onto the user's skin. Furthermore, from the viewpoint of limiting the sprayed area and spraying only the desired area, it is preferably 1.00 ml / min or less, more preferably 0.5 ml / min or less, and even more preferably 0.3 ml / min or less. Specifically, the discharge rate can be set to approximately 0.15 ml / min. The discharge rate can be appropriately set based on the current and voltage supplied to generate the electric field and the liquid being ejected. Note that the discharge rate is also affected by liquid characteristics such as molecular weight, type and conductivity, environmental factors such as temperature and humidity, and mechanical factors such as the nozzle structure, so it is preferable to set it taking these factors into consideration.

[0023] The spinnable distance (straight line distance) from the nozzle 123a to the surface of the object is preferably 10 mm or more, more preferably 15 mm or more, and even more preferably 20 mm or more, from the viewpoint of allowing time for the solvent to evaporate and forming dry fibers. Furthermore, from the viewpoint of limiting the area sprayed on the skin and making it easier to aim, it is preferably 300 mm or less, more preferably 200 mm or less, and even more preferably 150 mm or less.

[0024] As shown in Figure 4, the nozzle 123 comprises a nozzle body 125 that tapers in the direction of liquid ejection, and a protruding portion 129 that extends from the tip of the nozzle body 125 toward the ejection direction and has an ejection hole 123a.

[0025] As shown in Figure 4, the nozzle body 125 is formed in a cylindrical shape that tapers towards the direction of liquid ejection. In this embodiment, the nozzle body 125 has a tapered shape in which the outer diameter decreases in stages towards the ejection direction. The nozzle body 125 has a connecting portion 127 at the tip on the ejection direction side that connects to a projection 129. The connecting portion 127 has the smallest outer diameter D1 (see Figure 5) of the nozzle body 125. In other words, the nozzle body 125 has a larger diameter in the region behind the connecting portion 127 in the ejection direction than the connecting portion 127, thereby providing sufficient mechanical strength. Note that the nozzle body 125 is not limited to the tapered shape with gradually decreasing outer diameter described above, but any shape can be adopted as long as the connecting portion 127 has the smallest outer diameter D1 of the nozzle body 125. For example, the nozzle body 125 may have a tapered shape in which the outer diameter decreases continuously towards the ejection direction, or it may have a shape in which only a part of it is tapered.

[0026] As shown in Figure 5, the connecting portion 127 is formed in an R-shaped surface. Specifically, the connecting portion 127 is formed in an R-shaped surface that is convex radially inward of the protruding portion 129. More specifically, the radius of curvature (R) of the connecting portion 127 is preferably 0.1 mm or more, more preferably 0.2 mm or more, from the viewpoint of suppressing the concentration of the electric field at the connecting portion 127, thereby strengthening the electric field acting on the liquid and widening the range of distance over which the material can be discharged (spun). Furthermore, from the viewpoint of making the size of the nozzle 123 compact, it is preferably 5 mm or less, and more preferably 1 mm or less. In particular, if the radius of curvature (R) of the connection portion 127 is large, the nozzle body 125 becomes thinner overall, which increases pressure loss during discharge and may lead to a larger and more expensive mechanism for discharging liquid. Additionally, the thickness of the protruding portion 129 becomes thinner, which may reduce the mechanical strength of the protruding portion 129. However, by keeping the radius of curvature (R) of the connection portion 127 within the above numerical range, it is possible to maintain sufficient liquid discharge performance while ensuring sufficient mechanical strength, as well as miniaturizing the device and reducing costs.

[0027] The outer diameter D1 of the connecting portion 127 is preferably 1 mm or more, more preferably 2 mm or more, from the viewpoint of mechanical strength, and is preferably 5 mm or less, more preferably 3 mm or less, from the viewpoint of concentrating the electric field acting on the liquid and increasing the spinnable distance.

[0028] As shown in Figure 5, the protruding portion 129 extends from the tip of the nozzle body 125 toward the ejection direction and has an ejection hole 123a. Specifically, the protruding portion 129 is provided integrally with the nozzle body 125 via a connecting portion 127. However, the configuration in which the protruding portion 129 is provided integrally with the nozzle body 125 is not limited to this configuration, and it may also be configured as a separate component that can be retrofitted to the nozzle body 125.

[0029] The protruding portion 129 has an outer peripheral surface parallel to the ejection direction in at least a portion of it. In this embodiment, the protruding portion 129 has an outer peripheral surface parallel to the ejection direction from the connecting portion 127 to the outer peripheral end surface 129a of the protruding portion 129, which will be described later.

[0030] The maximum outer diameter D2 of the protrusion 129 is less than or equal to the outer diameter D1 of the connection portion 127 between the protrusion 129 and the nozzle body 125. Specifically, from the viewpoint of mechanical strength, the maximum outer diameter of the protrusion 129 is preferably 1 mm or more, more preferably 1.5 mm or more, and from the viewpoint of concentrating the electric field acting on the liquid and increasing the spinnable distance, it is preferably 3 mm or less, more preferably 2.5 mm or less. In this embodiment, the maximum outer diameter D2 of the protrusion 129 is the outer diameter of the parallel outer circumferential surface. Also, in this embodiment, the maximum outer diameter D2 of the protrusion 129 and the outer diameter D1 of the connection portion 127 of the nozzle body 125 are the same size.

[0031] The inner diameter D3 of the ejection hole 123a of the protruding portion 129 is preferably 0.2 mm or more, more preferably 0.5 mm or more, from the viewpoint of stable liquid delivery and suppression of liquid clogging. Furthermore, from the viewpoint of strengthening the electric field acting on the liquid and widening the range of distance over which it can be discharged (spun), it is preferably 2.00 mm or less, and more preferably 1.50 mm or less.

[0032] The length L1 of the protrusion 129 along the ejection direction is preferably 0.2 mm or more, and more preferably 0.4 mm or more, from the viewpoint of strengthening the electric field acting on the liquid and widening the range of distance over which it can be discharged (spun). On the other hand, if the length L1 of the protrusion 129 along the ejection direction is long, the narrow flow path portion will be longer, which will increase the pressure loss during discharge, potentially leading to a larger and more expensive mechanism for discharging the liquid. Also, because the protrusion 129 will have an elongated shape, its mechanical strength will decrease, and it may break when dropped, etc. From these viewpoints, the length L1 of the protrusion 129 along the ejection direction is preferably 3.0 mm or less, more preferably 2.5 mm or less, and even more preferably 1.5 mm or less. By keeping the length L1 of the protrusion 129 along the ejection direction within the above numerical range, it is possible to ensure sufficient mechanical strength while adequately maintaining liquid discharge performance, as well as miniaturizing the device and reducing costs. In particular, when the length L1 of the protrusion 129 along the ejection direction exceeds 3.0 mm, the pressure loss during discharge increases approximately proportionally with respect to the length L1, while the rate of increase in radio wave intensity decreases compared to when the length L1 is 3.0 mm or less. For this reason, from the viewpoint of efficiently increasing the electric field intensity while minimizing the increase in pressure loss, it is preferable to set the length L1 of the protrusion 129 along the ejection direction within the above numerical range. Here, "length L1" refers to the length (straight-line distance) along the ejection direction from the inflection point on the rear side of the connection part 127 in the ejection direction to the end of the protrusion 129 on the ejection direction side.

[0033] As shown in Figure 5, the outer peripheral end face 129a of the protrusion 129 on the ejection hole side is formed in an R-shape. Specifically, the outer peripheral end face 129a of the protrusion 129 on the ejection hole side is formed in an R-shape that is convex radially outward from the protrusion 129.

[0034] The radius of curvature (R) of the outer peripheral end face 129a is preferably 0.2 mm or more, more preferably 0.5 mm or more, from the viewpoint of strengthening the electric field acting on the liquid by suppressing disturbances in the electric field caused by the outer peripheral end face 129a, thereby widening the range of distance over which the liquid can be discharged (spun), and improving the directionality of the liquid discharge. Furthermore, from the viewpoint of miniaturizing the entire nozzle, it is preferably 5 mm or less, and more preferably 2 mm or less.

[0035] [Housing configuration and operation] As shown in Figures 1, 2, and 6, the electrostatic spray body 200 includes a housing 210 that encloses various components such as the power supply unit 243. As shown in Figure 2, the housing 210 includes a housing space 220 for housing the liquid storage unit 110, an insertion hole 221 for inserting the liquid storage unit 110 into the housing space 220, a gripping part 230 that can be grasped by the user, a main power operation part 241 for turning the power supply from the power supply unit 243 ON / OFF, and an operating operation part 242 that is operated to spray the liquid composition. Overall, it is shaped and sized so that the user can hold it with one hand. Specifically, the housing 210 is formed in a box shape (a cylindrical shape with an upper and lower surface) having an internal space in which the housing space 220 and the space for housing various components such as the power supply unit 243 are separated, and the cross section perpendicular to the axial direction (first direction, vertical direction in Figure 1) has an elliptical shape with a major axis and a minor axis. Furthermore, the housing 210 has a length in the direction along the axis of the nozzle 123 that is, for example, between 3 cm and 11 cm.

[0036] The housing 210 is made of an insulating material, that is, a material that has the property of not conducting electricity well. Note that "insulating" or "not conducting electricity well" as used here means, for example, 10 12This refers to having a volume resistivity (ASTM D257, JIS K6911) greater than Ωm. Examples of insulating materials used in the housing 210 and cover 140 include insulating organic materials such as synthetic resins, or insulating inorganic materials such as glass or ceramics. Examples of insulating organic materials include polypropylene (PP), polyacetal, polyetheretherketone (PEEK), polytetrafluoroethylene (PTFE), monomer cast nylon, etc. On the other hand, conductive materials are materials that have the property of easily conducting electricity, i.e., for example 10 -2 This refers to a material having a volume resistivity of Ωm or less.

[0037] The insertion hole 221 communicates with the housing space 220 within the housing 210, and the shape and size allow the liquid storage portion 110 of the cartridge 100 to be inserted into and removed from the housing space 220 by passing through the insertion hole 221. In this embodiment, the insertion hole 221 and the housing space 220 are formed at the end of the housing 210, making it possible to secure ample space on the other side for housing the charging structure, drive unit, etc.

[0038] As shown in Figures 1 and 2, the gripping section 230, the main power control section 241, and the operating section 242 are located on the other end of the housing 210. Specifically, the gripping section 230, the main power control section 241, and the operating section 242 are located behind the nozzle 123 in the liquid ejection direction. The main power control section 241 and the operating section 242 are mounted in a way that allows them to be operated from outside the housing 210. Specifically, the operating section 242 is located at the corner where the top surface and the rear surface (the rear surface in the liquid ejection direction) of the housing 210 intersect, and the main power control section 241 is located on the rear surface of the housing 210. In addition, the gripping section 230 is located below the electrostatic ejection body 200 below the operating section 242. The gripping portion 230 is shaped and sized to allow a user to grip it with one hand, and the power supply unit 243, voltage generation unit 244, output terminal 245, and drive unit 246, which will be described later, are arranged inside the gripping portion 230.

[0039] Here, we will explain the operations performed by operating the main power control unit 241 and the operating unit 242. When the cartridge 100 is housed in the housing space 220 of the housing 210, the output terminal 245 is electrically connected to the small electrode 121b provided inside the mounting body 121 of the cartridge 100 via a ring electrode provided on the cartridge 100. The drive unit 246 is mechanically connected to the second cylindrical member 112 provided on the cartridge 100.

[0040] When the main power control unit 241 is turned off, power is not supplied from the power supply unit 243 to the voltage generation unit 244 or the drive unit 246. Therefore, no voltage is generated from the voltage generation unit 244, and the drive unit 246 is not driven. Consequently, if the main power control unit 241 is turned off, even if the user accidentally operates the operating unit 242, the liquid composition contained in the liquid container 110 will not be electrostatically charged, and the liquid composition will not be ejected.

[0041] The operating unit 242 is configured, for example, by a switch that can switch between an ON state and an OFF state. When the main power operating unit 241 is in the ON state, turning the operating unit 242 ON supplies power from the power supply unit 243 to the voltage generating unit 244 and the drive unit 246. This drives the motor of the drive unit 246, generating rotational force, which is transmitted via the gears of the drive unit 246 to the second cylindrical member 112 provided in the cartridge 100, causing the second cylindrical member 112 to rotate. The rotation of the second cylindrical member 112 causes the piston rod 112a, which is screwed into the inner surface of the second cylindrical member 112, to advance toward the ejection unit 120, pushing the piston 112b toward the ejection unit 120, and the liquid composition in the first cylindrical member 111 is pushed toward the ejection unit 120. Furthermore, the voltage generation unit 244 generates a positive high voltage (for example, several kV to tens of kV) and sends the generated high voltage to the output terminal 245. The output terminal 245 sends the high voltage to a small electrode 121b provided inside the mounting body 121 of the cartridge 100 via a ring electrode provided on the cartridge 100. The small electrode 121b electrostatically charges the liquid composition flowing inside the cartridge 100 when the high voltage is applied.

[0042] Here, the voltage generated by the voltage generating unit 244 is preferably 3kV or more, more preferably 5kV or more, from the viewpoint of expanding the range of distance over which the yarn can be discharged (spun), and more preferably 20kV or less, and more preferably 15kV or less, from the viewpoint of balancing safety with miniaturization of the electrostatic ejection device.

[0043] Furthermore, the relationship between the voltage generated from the voltage generating unit 244 and the spinnable distance, i.e., "spinnable distance" ÷ "voltage" (mm / kV), is preferably 2.00 mm / kV or higher, more preferably 2.30 mm / kV or higher, even more preferably 2.60 mm / kV or higher, and from the viewpoint of limiting the sprayed area and spraying only the desired area, it is preferably 13.00 mm / kV or lower, more preferably 12.50 mm / kV or lower, and even more preferably 12.00 mm / kV or lower.

[0044] Furthermore, an electric field can be generated at the small electrode 121b when a voltage is applied. That is, a high potential difference electric field can be generated between the small electrode 121b and the object opposite it (ground potential). The liquid moves along the electric field lines that are perpendicular to the equipotential surfaces in this electric field.

[0045] In this manner, the electrostatically charged liquid composition flows from the liquid container 110 to the ejection unit 120, and upon reaching the nozzle 123, the liquid composition is ejected toward the object by the electrostatic force based on the potential difference between the charged liquid composition and the object. Subsequently, when the operating unit 242 is turned OFF, the ejection of the liquid composition stops.

[0046] The main power control unit 241 consists of a push button and a lamp indicator, and has a function to adjust the amount of liquid composition dispensed in multiple stages (two stages in this case: large and small). Pressing it once activates a prime mode that quickly delivers the liquid composition to the nozzle 123 without generating voltage. Pressing it again activates a spray mode that generates voltage and dispenses a small amount of liquid, and pressing it again activates a spray mode that generates voltage and dispenses a large amount of liquid. In other words, the mode of the main power control unit 241 adjusts the voltage supplied from the power supply unit 243 to the drive unit 246, and adjusts the rotation speed of the drive unit 246. This adjusts the amount of liquid composition pushed out (flowing in) from the liquid storage unit 110 to the discharge unit 120, and also adjusts the amount of liquid composition dispensed.

[0047] [Composition of liquids] The liquid contained in the liquid storage section 110 is not particularly limited, but examples include a liquid composition used in an electrostatic spraying device or an electrostatic spinning device, or a liquid composition for spinning (spinning solution). As such a liquid composition, for example, a solution of a film-forming polymer compound, more preferably a fiber-forming polymer compound, dissolved in a solvent can be used. As such a polymer compound, either a water-soluble polymer compound or a water-insoluble polymer compound can be used. It is preferable that the fiber-forming polymer compound includes a water-insoluble polymer compound.

[0048] When using a water-insoluble polymer compound, the liquid composition preferably contains the following components (a), (b), and (c), with a mass ratio (b / c) of component (b) to component (c) of 0.4 or more and 50 or less. (a) One or more volatile substances selected from alcohols and ketones (b) Water-insoluble polymers for fiber formation (c) water

[0049] Specifically, when using a water-insoluble polymer compound, the liquid composition contains 50% by mass or more of a volatile liquid agent selected from alcohols and ketones. The volatile liquid agent is a substance that is volatile in its liquid state. The vapor pressure of the volatile liquid agent is preferably 0.01 kPa or more and 106.66 kPa or less at 20°C, more preferably 0.13 kPa or more and 66.66 kPa or less, even more preferably 0.67 kPa or more and 40.00 kPa or less, and even more preferably 1.33 kPa or more and 40.00 kPa or less.

[0050] Among the volatile liquid agents, monohydric chain aliphatic alcohols, monohydric cyclic aliphatic alcohols, and monohydric aromatic alcohols are preferably used as alcohols. Examples of monohydric chain aliphatic alcohols include C1-C6 alcohols, examples of monohydric cyclic alcohols include C4-C6 cyclic alcohols, and examples of monohydric aromatic alcohols include benzyl alcohol and phenylethyl alcohol. Specific examples of these include ethanol, isopropyl alcohol, butyl alcohol, phenylethyl alcohol, n-propanol, and n-pentanol. One or more of these alcohols can be used.

[0051] Examples of volatile liquid agents include diC1-C4 alkyl ketones, such as acetone, methyl ethyl ketone, and methyl isobutyl ketone. These ketones can be used individually or in combination of two or more.

[0052] The volatile liquid agent more preferably contains one or more selected from ethanol, isopropyl alcohol, and butyl alcohol, more preferably contains one or more selected from ethanol and butyl alcohol, and even more preferably contains ethanol from the viewpoint of the feel of the formed fibers. The content of the above volatile liquid agent is preferably 85% by mass or more, preferably 90% by mass or more, and preferably 100% by mass or less of the total volatile liquid agent.

[0053] The content of the volatile liquid agent in the liquid composition is preferably 50% by mass or more, more preferably 55% by mass or more, and even more preferably 60% by mass or more. Furthermore, it is preferably 95% by mass or less, more preferably 94% by mass or less, and even more preferably 93% by mass or less. The content of the volatile liquid agent in the liquid composition is preferably 50% by mass or more and 95% by mass or less, more preferably 55% by mass or more and 94% by mass or less, and even more preferably 60% by mass or more and 93% by mass or less. By including the volatile liquid agent in the liquid composition in this proportion, the liquid composition can be sufficiently volatilized when performing the electrostatic spray method, and a film containing fibers can be formed on the surface of the skin or nails.

[0054] Furthermore, from the viewpoint of high volatility and the feel of the formed fibers, the amount of ethanol is preferably 50% by mass or more, more preferably 65% ​​by mass or more, and even more preferably 80% by mass or more, based on the total amount of the volatile liquid agent. It is also preferable that it be 100% by mass or less. The amount of ethanol is preferably 50% by mass or more and 100% by mass or less, more preferably 65% ​​by mass or more and 100% by mass or less, and even more preferably 80% by mass or more and 100% by mass or less, based on the total amount of the volatile liquid agent.

[0055] Furthermore, the liquid composition preferably contains a water-insoluble polymer for fiber formation. The water-insoluble polymer for fiber formation is a substance that can dissolve in a volatile liquid agent. Here, dissolution means that the substance is dispersed at 20°C, and that the dispersion is uniform to the naked eye, preferably transparent or translucent to the naked eye.

[0056] Water-insoluble polymers for fiber formation are polymers that are soluble in volatile substances but insoluble in water. In this specification, "water-soluble polymer" refers to a polymer that, when weighed at 1 atmosphere and 23°C, is immersed in 10 g of deionized water, and after 24 hours, at least 0.5 g of the immersed polymer dissolves in water. On the other hand, in this specification, "water-insoluble polymer" refers to a polymer that, when weighed at 1 atmosphere and 23°C, is immersed in 10 g of deionized water, and after 24 hours, at least 0.5 g of the immersed polymer does not dissolve; in other words, it refers to a polymer whose dissolvable amount is less than 0.5 g.

[0057] Examples of water-insoluble polymers with fiber-forming ability include fully saponified polyvinyl alcohol that can be insolubilized after film formation, partially saponified polyvinyl alcohol that can be crosslinked after film formation when used in combination with a crosslinking agent, oxazoline-modified silicones such as poly(N-propanoylethyleneimine) graft-dimethylsiloxane / γ-aminopropylmethylsiloxane copolymer, polyvinyl acetal diethylaminoacetate, zein (a major component of corn protein), polyester, polylactic acid (PLA), polyacrylonitrile resin, acrylic resins such as polymethacrylic acid resin, polystyrene resin, polyvinyl butyral resin, polyethylene terephthalate resin, polybutylene terephthalate resin, polyurethane resin, polyamide resin, polyimide resin, and polyamideimide resin. One or more of these water-insoluble polymers can be used in combination. Of these water-insoluble polymers, it is preferable to use one or more selected from fully saponified polyvinyl alcohol, which can be insolubilized after film formation; partially saponified polyvinyl alcohol, which can be crosslinked after film formation when used in combination with a crosslinking agent; acrylic resins such as polyvinyl butyral resin, polyurethane resin, and polymethacrylic acid resin; oxazoline-modified silicones such as polyvinyl acetal diethylaminoacetate and poly(N-propanoylethyleneimine) graft-dimethylsiloxane / γ-aminopropylmethylsiloxane copolymer; polylactic acid (PLA); and zein. Of these water-insoluble polymers, partially saponified polyvinyl alcohol, fully saponified polyvinyl alcohol, polyvinyl butyral resin, polymethacrylic resin, and polyurethane resin are more preferred from the viewpoint of dispersibility in alcohol solvents and the feel of the fibers, with partially saponified polyvinyl alcohol, fully saponified polyvinyl alcohol, and polyvinyl butyral resin being even more preferred. Polyvinyl butyral resin is particularly preferred from the viewpoint of being able to stably and efficiently form a fiber-containing film on the surface of the skin or nails, and from the viewpoint of achieving both film durability, film formation, skin conformability, and durability.

[0058] The content of the water-insoluble polymer for fiber formation in the liquid composition is preferably 1% by mass or more, more preferably 3% by mass or more, and even more preferably 5% by mass or more. Furthermore, it is preferably 30% by mass or less, more preferably 25% by mass or less, and even more preferably 20% by mass or less. The content of the water-insoluble polymer for fiber formation in the liquid composition is preferably 1% by mass or more and 30% by mass or less, more preferably 3% by mass or more and 25% by mass or less, and even more preferably 5% by mass or more and 20% by mass or less. By including the water-insoluble polymer for fiber formation in the liquid composition in this proportion, a fibrous coating can be formed stably and efficiently.

[0059] Furthermore, the liquid composition may contain water. Water ionizes and becomes charged compared to non-ionizing solvents such as ethanol, or it can dissolve ionic components and induce ionization, thereby imparting conductivity to the liquid composition. As a result, a fibrous film is stably formed on the surface of the skin or nails by electrostatic spraying. In addition, water contributes to improved adhesion, durability, and appearance of the film formed by electrostatic spraying to the skin or nails. From the viewpoint of obtaining these effects, it is preferable that the liquid composition contains 0.2% to 20% by mass of water, more preferably 0.3% to 15% by mass, and even more preferably 0.4% to 10% by mass from the viewpoint of fibrous film formation even in high humidity environments.

[0060] The liquid composition may further contain other components. Examples of other components include polyols other than the volatile liquid agents mentioned above, oils that are liquid at 25°C, plasticizers for water-insoluble polymers for fiber formation, conductivity regulators for liquid compositions, binders, powders such as coloring pigments and extender pigments, dyes, fragrances, repellents, antioxidants, stabilizers, preservatives, and various vitamins. When other components are included in the liquid composition, the content of these other components is preferably 0.1% by mass or more and 30% by mass or less, and more preferably 0.5% by mass or more and 20% by mass or less.

[0061] The viscosity of the liquid composition is preferably 2 mPa·s to 3000 mPa·s at 25°C, more preferably 10 mPa·s to 1500 mPa·s, even more preferably 15 mPa·s to 1000 mPa·s, and even more preferably 15 mPa·s to 800 mPa·s, from the viewpoints of stably forming a fibrous film, spinnability during electrostatic spraying, improving the durability of the film, and improving the feel of the film. The viscosity of the liquid composition is measured at 25°C using an E-type viscometer. For example, an E-type viscometer (VISCONICEMD) manufactured by Tokyo Keiki Co., Ltd. can be used. In this case, the measurement conditions are 25°C, rotor No. 43 of the cone plate, and the rotation speed is selected appropriately according to the viscosity: 5 rpm for viscosities of 500 mPa·s or more, 10 rpm for viscosities of 150 mPa·s or more but less than 500 mPa·s, and 20 rpm for viscosities less than 150 mPa·s.

[0062] [Advantages of the electrostatic spray device according to this embodiment] As described above, the electrostatic spraying device 10 according to this embodiment generally comprises an electrode for applying voltage to a liquid and a nozzle 123 having a spray hole 123a for spraying the liquid toward an object. The nozzle 123 comprises a nozzle body 125 that tapers toward the direction of liquid spraying and a protruding portion 129 that protrudes toward the spraying direction from the tip of the nozzle body 125 and has a spray hole 123a. The maximum outer diameter D2 of the protruding portion 129 is less than or equal to the outer diameter D1 of the connection portion 127 between the protruding portion 129 and the nozzle body 125, and the outer peripheral end face 129a on the spray hole side of the protruding portion 129 is formed in an R-shape.

[0063] With the electrostatic spray device 10 having such a configuration, it is possible to strengthen the electric field acting on the liquid and widen the range of distance over which the liquid can be discharged (spun). Specifically, with the electrostatic spray device 10 according to this embodiment, the protruding portion 129 having an outer diameter D2 less than or equal to the outer diameter D1 of the connection portion 127 with the nozzle body 125 makes it possible to concentrate the electric field at the discharge hole 123a. Furthermore, with the electrostatic spray device 10 according to this embodiment, since the outer peripheral end surface 129a on the discharge hole side of the protruding portion 129 is formed in an R-shape, it is possible to suppress disturbances in the electric field caused by the outer peripheral end surface 129a, making it possible to concentrate the electric field at the discharge hole 123a even more. As a result, with the electrostatic spray device 10 according to this embodiment, it is possible to strengthen the electric field acting on the liquid even at low voltages, making it possible to increase the amount of charged liquid discharged per unit time and to discharge the liquid over long distances. Furthermore, the more the electric field is concentrated at the ejection hole 123a, the steeper the slope of the equipotential lines becomes, resulting in a greater spread of the liquid relative to the distance from the ejection hole 123a, which is advantageous for drying the liquid. Therefore, with the electrostatic ejection device 10 according to this embodiment, spinnability can be ensured even at short distances. Moreover, with the electrostatic ejection device 10 according to this embodiment, it is possible to use it at a low voltage, which allows for miniaturization of the device, cost reduction, and improved safety.

[0064] Furthermore, in the electrostatic ejection device 10 according to this embodiment, the connection portion 127 is formed in an R-shape, which suppresses disturbances in the electric field, thus enabling stable spinning. This further improves spinnability.

[0065] Furthermore, in the electrostatic ejection device 10 according to this embodiment, the outer peripheral end face 129a on the ejection hole side of the protrusion 129 is formed in an R-shape that is convex radially outward of the protrusion 129, and the connecting portion 127 is formed in an R-shape that is convex radially inward of the protrusion 129. With this configuration, the charge can be concentrated on the protrusion 129, making the electric field stronger. This makes it possible to further improve spinnability.

[0066] Furthermore, in the electrostatic ejection device 10 according to this embodiment, the protrusion 129 has an outer peripheral surface parallel to the ejection direction in at least a portion of it, which makes it possible to suppress disturbances in the electric field compared to a configuration in which the entire outer peripheral surface is formed with irregularities, thereby improving spinnability. In addition, in the electrostatic ejection device 10 according to this embodiment, the thickness of the protrusion 129 can be ensured by having a parallel outer peripheral surface, which makes it possible to improve the moldability of the protrusion 129 and suppress damage in the event of dropping, etc., compared to a thin configuration in which the outer peripheral end surface 129a is immediately accessible from the connecting portion 127.

[0067] [Differentiation] Although this embodiment has been described above as a preferred embodiment of the present invention, the technical scope of the present invention is not limited to the scope described in the above-described embodiment. Various modifications or improvements can be made to the above embodiment.

[0068] For example, in the embodiment described above, the electrostatic spray device was described as a standalone type in which a power supply unit 243 and a voltage generating unit 244 are built into the housing 210, but it is not limited to this. For example, a base station (not shown) containing the power supply unit 243 and the voltage generating unit 244 may be provided separately, and the base station and the housing 210 may be connected by a connecting cable or the like, thereby applying voltage to the output terminal 245 and the drive unit 246 of the housing 210.

[0069] Furthermore, although the liquid storage section 110 was described as a cylinder-shaped liquid storage section 110 capable of containing liquid in the above-described embodiment, it is not limited to this, and various arbitrary configurations such as a conductive liquid storage section formed in the shape of a bag can be adopted.

[0070] It is clear from the claims that the above-mentioned modifications are included within the scope of the present invention. [Examples]

[0071] The present invention will be described in detail below based on examples, but these examples are not intended to limit the object of the present invention.

[0072] [Example 1, Example 2, Comparative Example 1] First, the effect of the presence or absence of the protrusion 129 in the nozzle 123 on spinning performance will be explained using Examples 1 and 2 and Comparative Example 1.

[0073] [Example 1] The electrostatic spray device according to Example 1 was manufactured using PP resin for the nozzle 123. The electrostatic spray device according to Example 1 has a protrusion 129 on the nozzle 123, and the radius of curvature (R) of the outer peripheral end face 129a of the protrusion 129 was 0.5 mm.

[0074] [Example 2] An electrostatic spray device of Example 2 was obtained in the same manner as in Example 1, except that the radius of curvature (R) of the outer peripheral end face 129a of the protrusion 129 was changed. The radius of curvature (R) of the outer peripheral end face 129a of the protrusion 129 in the electrostatic spray device of Example 2 was 2.0 mm.

[0075] [Comparative Example 1] A comparative example of electrostatic spraying device 1 was obtained in the same manner as in Example 1, except that the protruding portion 129 was eliminated.

[0076] For the electrostatic ejection apparatuses of Examples 1 and 2 and Comparative Example 1, liquid was ejected under the following spinning conditions, and the spinnable distance (mm) between the ejection hole 123a of the nozzle 123 and the surface of the object was measured. Measurements were also taken under three environmental conditions (room temperature and humidity): approximately 25°C and 50%, approximately 30°C and 65%, and approximately 30°C and 80%. The spinnable distance (mm) and the ratio of "spinnable distance" to "voltage" are shown in Table 1. [Spinning conditions] Formula: Polymer (PVB) + EtOH • Spinning target: Grounded aluminum foil Voltage: 10.5kV ·Spray amount: 0.15g / min

[0077] [Table 1]

[0078] As shown in Table 1, Example 1, compared to Comparative Example 1, is capable of spinning at a greater distance when the environment (room temperature and humidity) is approximately 25°C and 50% and approximately 30°C and 65%, and at both a closer and a greater distance when the environment is approximately 30°C and 80%. Similarly, Example 2 is capable of spinning at a greater distance when the environment (room temperature and humidity) is approximately 25°C and 50%, and at a greater distance when the environment is approximately 30°C and 65% and approximately 30°C and 80%. In other words, the electrospinning apparatuses of Examples 1 and 2 have a wider range of spinning distances compared to Comparative Example 1, which does not have the protrusion 129, at the same voltage.

[0079] Furthermore, for the electrostatic spraying apparatuses of Examples 1 and 2 and Comparative Example 1, liquid was sprayed under the following spinning conditions, and the spinnable distance (mm) between the spray hole 123a of the nozzle 123 and the surface of the object was measured. Measurements were also taken for environmental conditions (room temperature and humidity) of approximately 25°C and 50%, approximately 30°C and 65%, and approximately 30°C and 80%. The spinnable distance (mm) and the ratio of "spinnable distance" to "voltage" are shown in Table 2. [Spinning conditions] Formula: Polymer (PVB) + EtOH • Spinning target: Grounded aluminum foil Voltage: 10.0kV ·Spray amount: 0.20g / min

[0080] [Table 2]

[0081] As shown in Table 2, Example 1, compared to Comparative Example 1, allows spinning at closer and further locations when the environment (room temperature and humidity) is approximately 25°C and 50% and approximately 30°C and 65%, and at a further location when the environment is approximately 30°C and 80%. Furthermore, compared to Comparative Example 1, Example 2 allows spinning at closer and further locations when the environment (room temperature and humidity) is approximately 25°C and 50%, approximately 30°C and 65%, and approximately 30°C and 80%.

[0082] The results shown in Tables 1 and 2 indicate that the electrospinning apparatuses of Examples 1 and 2 have a wider spinning distance range compared to Comparative Example 1, which does not have the protruding portion 129, even when the voltage is lowered and the amount of charged liquid ejected per unit time is increased.

[0083] [Example 3, Comparative Example 2, Comparative Example 3] Next, the influence of the presence or absence of a rounded surface on the protrusion 129 of the nozzle 123 and the relationship between the diameter of the protrusion 129 and the connecting portion 127 on spinning performance will be explained using Example 3 and Comparative Examples 2 and 3.

[0084] [Example 3] The electrostatic spraying device according to Example 3 was manufactured using PE resin for the nozzle 123. The electrostatic spraying device according to Example 3 has a protrusion 129 on the nozzle 123, and the radius of curvature (R) of the outer peripheral end face 129a of the protrusion 129 was 0.5 mm. The maximum outer diameter of the protrusion 129 was φ2.2 mm, and the outer diameter of the connection portion 127 between the protrusion 129 and the nozzle body 125 was φ2.2 mm.

[0085] [Comparative Example 2] The electrostatic spray device of Comparative Example 2 was obtained in the same manner as in Example 3, except that the outer peripheral end face 129a of the protruding portion 129 was not formed in an R-shape but in a right-angle shape.

[0086] [Comparative Example 3] A comparative electrostatic spray device of Comparative Example 3 was obtained in the same manner as in Example 3, except that the maximum outer diameter of the protrusion 129 was set to φ3.0 mm and the radius of curvature (R) of the outer peripheral end face 129a of the protrusion 129 was set to 0.2 mm.

[0087] For the electrostatic spraying devices of Example 3 and Comparative Examples 2 and 3, liquid was sprayed under the following spinning conditions, and the spinnable distance (mm) between the spray hole 123a of the nozzle 123 and the surface of the object was measured. The spinnable distance (mm) and "'spinnable distance' ÷ 'voltage'" are shown in Table 3. [Spinning conditions] Formula: Ethanol 99.5% (88%) + PVB (12%) ·Environment: Room temperature 23.1℃, humidity 52.2% • Spinning target: Grounded aluminum foil Voltage: 10.0kV ·Spray amount: 0.15g / min

[0088] [Table 3]

[0089] As shown in Table 3, Example 3, which has an R-shaped surface on the protrusion 129, can spin at both closer and farther distances compared to Comparative Example 2, which does not have an R-shaped surface on the protrusion 129. Furthermore, Example 3, in which the maximum outer diameter of the protrusion 129 is less than or equal to the outer diameter of the connecting portion 127, can spin at both closer and farther distances compared to Comparative Example 3, in which the maximum outer diameter of the protrusion 129 is greater than the outer diameter of the connecting portion 127. In other words, the electrospinning apparatus of Example 3 has a wider range of spinnable distances compared to Comparative Examples 2 and 3 at the same voltage. [Explanation of Symbols]

[0090] 10: Electrostatic spray device 100: Cartridge 110: Liquid storage section 120: Spout part 122: Connector 123: Nozzle 125: Nozzle body 127: Connection part 129:Protrusion 129a: Outer edge surface 123a:Blowout hole 210: Housing 220: Containment space 221: Insertion hole 241: Main power operation section 242: Operating Unit 243: Power supply section 244: Voltage generation unit 245: Output terminal 246: Drive unit

Claims

1. An electrostatic ejection device that applies a voltage to a liquid to eject the liquid, An electrode for applying a voltage to the liquid; a nozzle having a nozzle hole for ejecting the liquid toward a target; Equipped with the nozzle includes a nozzle body tapered in a liquid ejection direction, and a protruding portion protruding from a tip of the nozzle body in the ejection direction and having the ejection hole; a maximum outer diameter of the protrusion is equal to or smaller than an outer diameter of a connection portion between the protrusion and the nozzle body, The outer peripheral end surface of the protruding portion on the ejection hole side is formed into a rounded shape. Electrostatic ejection device.

2. The connection portion is formed into a rounded surface.

2. The electrostatic ejection device of claim 1.

3. The outer peripheral end surface of the protruding portion on the ejection hole side is formed into an R-surface shape that is convex radially outward of the protruding portion, The connection portion is formed with a rounded surface that is convex radially inward of the protrusion.

3. The electrostatic ejection device of claim 2.

4. The protruding portion has an outer circumferential surface that is at least partially parallel to the ejection direction.

4. The electrostatic ejection device according to claim 1.

5. The maximum outer diameter of the protrusion is 5 mm or less.

4. The electrostatic ejection device according to claim 1.

6. The length of the protrusion along the ejection direction is 0.2 mm or more and 3.0 mm or less.

4. The electrostatic ejection device according to claim 1.

7. The nozzle is made of a non-conductive synthetic resin.

4. The electrostatic ejection device according to claim 1.

8. Further comprising a voltage generating unit that applies a voltage to the electrodes, The voltage generating unit is configured to be capable of applying a voltage of 3 kV or more and 20 kV or less.

4. The electrostatic ejection device according to claim 1.

9. It is a handheld type device that can be held by the user.

4. The electrostatic ejection device according to claim 1.

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