JP5833781B1 - Electrostatic spraying equipment - Google Patents

Abstract

An electrostatic spraying device and the like capable of stably spraying even a liquid containing particles are provided. The electrostatic spraying device 100 includes a flow pipe 1 forming a first flow path F1 whose inner surface is formed of a conductive wall, and communicates with the first flow path F1 and is larger than the inner diameter of the first flow path F1. The nozzle 2 which forms the 2nd flow path F2 which has a small internal diameter, and the 1 or several linear member 8 arrange | positioned so that it may extend in the axial direction of the flow pipe 1 in the flow pipe 1 are provided. [Selection] Figure 1

Description

  The present invention relates to an electrostatic spraying device.

  Conventionally, a so-called electrostatic spraying method is known in which a charged liquid is discharged from a cylinder, and a large number of fine droplets are formed by a repulsive force due to electrostatic force and supplied to an object.

JP2013-237002A

  The present inventors are examining electrostatic spraying of a liquid containing particles. However, as a result of investigations by the present inventors, in the conventional technology, when the liquid containing particles is discharged from the cylinder, there is a problem that the cylinder is clogged and it is difficult to stably spray electrostatically. found.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide an electrostatic spraying device and the like that can stably perform electrostatic spraying even with a liquid containing particles.

  As a result of intensive studies by the present inventors, it has been found that if a linear member is disposed so as to extend in the axial direction of the flow tube in the flow tube disposed in front of the nozzle, a liquid containing particles can be stably electrostatically sprayed. It was.

The electrostatic spraying device according to the present invention includes a flow pipe that forms a first flow path having an inner surface formed of a conductive wall;
A nozzle that communicates with the first flow path and forms a second flow path having an inner diameter smaller than the inner diameter of the first flow path;
1 or a plurality of linear members arranged in the flow pipe so as to extend in the axial direction of the flow pipe.

  Here, the outer diameter of the linear member may be 50 to 500 μm.

  Moreover, the said electrostatic spraying apparatus can have three or more of the said linear members.

  An electrostatic spraying method according to the present invention is an electrostatic spraying method using the above-described electrostatic spraying device, and includes a step of supplying a liquid containing particles into the flow tube.

  ADVANTAGE OF THE INVENTION According to this invention, even if it is the liquid containing particle | grains, the electrostatic spray apparatus etc. which can be electrostatically sprayed stably are provided.

FIG. 1 is a schematic configuration diagram of an electrostatic spraying apparatus according to an embodiment of the present invention. 2A is a sectional view taken along the line IIa-IIa in FIG. 1, and FIG. 2B is a sectional view taken along the line IIb-IIb in FIG.

  FIG. 1 is a partially broken schematic view of an electrostatic spraying apparatus 100 according to an embodiment of the present invention. The electrostatic spraying apparatus 100 according to the present embodiment includes a nozzle unit 10, a counter electrode 20, a power supply 30, a liquid supply unit 40, and a nozzle unit moving unit 50.

  The nozzle unit 10 mainly includes a flow pipe 1, a nozzle 2, and a cover 3.

  The flow tube 1 is a cylinder having a flange 1a at the upper end, and the inner diameter D1 is constant. The flow pipe 1 is made of a conductive material such as stainless steel, for example, and forms a first flow path F1 having an inner surface formed of a conductive wall.

  When the length of the first flow path F1 is L1 and the inner diameter of the first flow path F1 is D1, L1 / D1 [−] can be 35 or more, preferably 40 or more, more preferably 50 or more. is there. The upper limit of L1 / D1 [-] is not particularly limited, but is preferably 100 or less, more preferably 80 or less, and still more preferably 60 or less.

  Specifically, D1 can be 0.5 to 2.0 mm, and preferably 0.5 to 1.0 mm. The length L1 can be 20 to 100 mm, preferably 40 mm or more, and preferably 80 mm or less.

  The nozzle 2 is provided at the tip of the flow tube 1. The nozzle 2 is a tube made of a conductive material such as stainless steel or an insulating material such as glass, and forms a second flow path F2 communicating with the first flow path F1.

  The inner diameter D2 of the second flow path F2 is smaller than the inner diameter D1 of the first flow path F1. Specifically, D2 can be 0.1 to 0.5 mm, preferably 0.1 to 0.3 mm.

  The length L2 of the second flow path F2 is not particularly limited, but is preferably smaller than the length of the first flow path F1. Specifically, L2 can be 5 to 20 mm, and is preferably 5 to 10 mm.

  In the present embodiment, the nozzle 2 has a collar-shaped support 2s on the outer periphery thereof, and the support 2s is placed under the flow pipe 1 via the O-ring 2b with the upper part of the nozzle 2 being inserted into the flow pipe 1. It is in contact with the end face.

  The cover 3 has a shape that covers the flow pipe 1 and the nozzle 2 and has an opening that communicates with the first flow path F1 at the top. The cover 3 is made of an electrically insulating material such as a resin (PTFE or the like). An internal thread is cut on the inner surface of the upper opening of the cover 3 and a pipe joint 4 is connected thereto. The pipe joint 4 includes a joint body 4a and a nut 4b that connects the tip of the line L10 to the joint body 4a.

  In the electrostatic spraying apparatus 100 according to the present embodiment, a plurality of linear members 8 having a circular cross section in the axial direction are arranged in the flow tube 1. Although there is no restriction | limiting in particular in the number of the linear members 8, For example, it can be 1, 2, 3, 4, or 5 pieces. 1 and 2, it has three linear members. In the case of having three or more linear members, the linear members can be arranged at the vertices of a regular polygon (regular triangle in FIG. 2B) when viewed from the axial direction. Four can be square, and five can be regular pentagons.

  The diameter of the linear member 8 should just be smaller than the internal diameter of the flow pipe | tube 1, can be set to 50-500 micrometers, and can be set to 100-400 micrometers. The tip of the linear member 8 on the nozzle side can be in contact with the nozzle 2 and can be separated from the nozzle 2. The distance at which the linear member 8 is separated from the nozzle 2 can be, for example, 0.005 to 20.00 mm. Further, the linear members 8 are arranged apart from each other in the flow pipe 1. The distance between the linear members 8 can be set to 0.1 to 0.5 mm, for example. Further, the linear member 8 is disposed away from the flow pipe 1. The distance between the linear member 8 and the flow tube 1 can be 0.1 to 0.5 mm. Further, the length of the linear member 8 extending in the axial direction in the flow tube 1 is not particularly limited, but may be, for example, 30 mm or more.

  The material of the linear member 8 may be a resin such as polyethylene or polypropylene, or a metal such as stainless steel.

  In this embodiment, the upper end of the linear member 8 is bent into an L shape to form a support portion 8a, and the support portion 8a is placed on the flange 1a of the flow pipe. For example, the support portion 8a can be fixed to the flange 1a using an adhesive, an adhesive tape, or the like.

  The counter electrode 20 is disposed on the opposite side of the flow tube 1 with the nozzle 2 interposed therebetween. The counter electrode 20 is disposed on an extension line of the first flow path F <b> 1 and is separated from the flow pipe 1 and the nozzle 2. The counter electrode 20 is preferably grounded.

  In this embodiment, the counter electrode has a plate shape, and the substrate SB to be coated is placed on the counter electrode.

  The power source 30 applies a voltage between the flow tube 1 and the counter electrode 20. Usually, the voltage is a direct current, and for example, it is preferable to supply the voltage in a pulse form. Although a voltage is not specifically limited, In this embodiment, it can be set to 5-20 kV. The voltage is preferably applied to the counter electrode 20 so as to be positive on the flow tube 1 side, but may be negative.

  The liquid supply unit 40 is a device that supplies liquid to the first flow path F1 through the line L10.

  In the present embodiment, the liquid supply unit 40 includes a tank 41 that stores liquid, and a pump 42 that supplies the resist solution from the tank 41 to the flow pipe 1 via the line L10. In the present embodiment, by supplying a gas such as nitrogen gas to the tank 41 in which the pump 42 is in a sealed state, the liquid is supplied to the first flow path F1 through the line L10.

In this embodiment, the liquid supply part 40 supplies the liquid containing particle | grains with respect to the 1st flow path F1. Examples of the particles are metal particles such as gold, silver, copper, and platinum, graphite particles, molybdenum disulfide particles, oxide particles such as SiO ₂ and TiO ₂ , resin particles such as PTFE, and phosphors. The average particle diameter (D50 of volume-based particle size distribution by laser diffraction / scattering method) of the particles can be, for example, 1 to 50 μm. Examples of liquids in which particles are dispersed include various polar solvents and nonpolar solvents such as water, oil, and organic solvents. A preferable viscosity range of the liquid in which the particles are dispersed is 5 to 1000 mPa · s.

  The nozzle unit moving unit 50 moves the nozzle unit 10 relative to the counter electrode 20. Specifically, for example, when the object is the substrate SB, the nozzle unit 10 can move independently in two axes in a plane horizontal to the surface of the substrate SB. Thereby, the liquid can be applied to a desired portion on the substrate SB. Moreover, it is preferable that the nozzle unit moving part 50 can move the nozzle unit 10 with respect to the counter electrode 20 also in a direction perpendicular to the substrate SB. Thereby, it is easy to adjust the distance between the tip of the nozzle 2 and the substrate SB. An example of a preferable distance between the nozzle 2 and the substrate SB is 10 to 100 mm.

  Then, the coating method using the electrostatic spraying apparatus 100 of this embodiment is demonstrated.

  First, the substrate SB to be applied is placed on the counter electrode 20. Subsequently, a voltage is applied between the flow tube 1 and the counter electrode 20 by the power supply 30. Further, the pump 42 is driven to supply the liquid in the tank 41 to the ends of the first flow path F1 and the second flow path F2 via the line L10. The liquid is charged by being charged by the flow tube 1, the liquid protruding from the nozzle 2 forms a Taylor cone, and a charged droplet is ejected from the tip of the cone toward the counter electrode having the opposite charge. . At this time, in this embodiment, since the linear member 8 is arrange | positioned in the flow tube 1, the liquid containing particle | grains can be electrostatically sprayed stably.

  The reason why such an effect is obtained is not clear, but the presence of the linear member 8 rectifies the flow in the flow pipe 1 and suppresses concentration of particles inside the narrow nozzle. It is considered that one of the causes is that clogging of the particles is suppressed.

The present invention is not limited to the above embodiment, and various modifications can be made.
For example, in the above embodiment, the nozzle 2 is inserted into the flow pipe 1, but the present invention is not limited to this. is there. The nozzle 2 may be formed of an electrically insulating material instead of a conductive material.

  Moreover, in the said embodiment, although the internal diameter D1 of the 1st flow path F1 is constant, the taper pipe which has the inclination whose angle of the inner surface with respect to an axis line is 15 degrees or less in the cross section containing an axis | shaft may be sufficient, for example. The inner diameter D1 in this case can be defined as an average diameter integrated along the axial direction. The same applies to the second flow path F2 of the nozzle 2.

  The shape of the flow pipe 1 is not particularly limited as long as the first flow path F1 can be formed. For example, the flange 1a may not be provided.

  Needless to say, the cover 3 is not essential. For example, the line L10 may be directly connected to the flow pipe 1.

  In the present embodiment, since the liquid application target is the substrate SB, the counter electrode 20 is also plate-shaped, but the shape of the counter electrode 20 can be changed to a desired form according to the shape of the application target. . Further, the object to be applied is not particularly limited, and for example, the liquid can be applied to various objects such as a substrate having an uneven surface.

  Also, the configuration of the liquid supply unit 40 is not particularly limited. For example, a configuration in which a pump is connected to the line L10, a configuration in which the pump 42 is a compressed gas source, or a liquid supply amount is small, and the first flow path In the case where the liquid can be supplied only by the negative pressure or the head difference in F1, only the line L10 may be used. In short, it is sufficient if the liquid can be supplied to the first flow path F1.

  Further, the cross-sectional shape of the linear member is not particularly limited to a circle, and may be a polygon or an ellipse. The outer diameter when the cross section is not circular can be an equivalent circle diameter. Moreover, the fixing method of a linear member is not limited to the above-mentioned form.

Example 1A
Electrostatic spraying was attempted for 3 minutes at a voltage of 5 to 10 kV using the electrostatic spraying apparatus as shown in FIGS.
Liquid: Press working oil (viscosity: 1-10 cP) containing solid lubricant (graphite particles, average particle size: 1-10 μm)
Flow pipe: made of stainless steel, first flow path F1 length 44.1 [mm], first flow path F1 inner diameter 1 mm
Nozzle: made of stainless steel, length L2 of the second flow path F2 = 9 mm, inner diameter of the second flow path F2 is 200 μm
Linear member: Made of stainless steel (SUS), outer diameter 300 μm, length 43 mm
Arrangement of linear members: A linear member is arranged at the apex of a square and fixed by an upper support part. Substrate (Si substrate), distance between substrate and nozzle 2 40 mm

(Example 1B)
The same operation as in Example 1A was performed except that the material of the linear member was polyethylene (PE).

(Comparative Example 1)
The procedure was the same as Example 1A except that no linear member was arranged.

(Examples 2A and 2B, Comparative Example 2)
Example 1A, 1B, and Comparative Example 1 were performed except that the inner diameter of the second flow path F2 of the nozzle was set to 300 μm.

(Examples 3A and 3B, Comparative Example 3)
Example 1A, 1B, and Comparative Example 1 were performed except that the inner diameter of the second flow path F2 of the nozzle was 500 μm.
The results are shown in Table 1.

  DESCRIPTION OF SYMBOLS 1 ... Flow pipe, 2 ... Nozzle, 8 ... Linear member, 20 ... Counter electrode, 30 ... Power supply, 40 ... Liquid supply part, F1 ... First flow path, F2 ... Second flow path, 100 ... Electrostatic spraying apparatus.

Claims (4)

A flow pipe forming a first flow path having an inner surface formed of a conductive wall;
A nozzle that communicates with the first flow path and forms a second flow path having an inner diameter smaller than the inner diameter of the first flow path;
One or more linear members disposed in the flow pipe so as to extend in the axial direction of the flow pipe;
With
The linear member is spaced from the inner surface of the flow tube;
The electrostatic spraying device , wherein the one or more linear members are not inserted into the second flow path .   The electrostatic spraying device according to claim 1, wherein an outer diameter of the linear member is 50 to 500 μm.   The electrostatic spraying device according to claim 1, wherein the electrostatic spraying device has three or more linear members. An electrostatic spraying method using the electrostatic spraying device according to any one of claims 1 to 3,
An electrostatic spraying method comprising a step of supplying a liquid containing particles into the flow tube.

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