Coating equipment

Abstract

This technology provides a way to suppress the risk of increased film thickness at the starting point of the coating process. [Solution] The coating apparatus 100 according to the present disclosure comprises a tank 31 for storing coating material, a die 11 for discharging coating material, a first pipe 1 connecting the die 11 and the tank 31, a second pipe 2 branching off from the first pipe 1 and connected to the tank 31, a coating valve 22 provided between the branching point 1A where the second pipe 2 branches off from the first pipe 1 and the die 11 in the first pipe 1, a circulation valve 23 provided in the second pipe 2, a pump 32 positioned between the branching point 1A and the tank 31 in the first pipe 1, a suck-back valve 21 positioned between the die 11 and the coating valve 22 in the first pipe 1, a start-end open valve 13 provided in the die 11, and a third pipe 3 connecting the start-end open valve 13 and the tank 31.

Description

Technical Field

[0001] The present disclosure relates to a coating device.

Background Art

[0002] The coating device disclosed in Patent Document 1 closes the coating valve while discharging the coating material from the die, and then drives the suck-back valve to draw in the coating material near the tip of the die. As a result, the dripping of the coating material is good, and the control of the end shape of the coating film can be easily executed.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The inventors of the present application have discovered the following technical problems. Using such a coating device, a plurality of coating films can be continuously formed. The coating film includes a coating start portion formed immediately after starting the coating. However, when the suck-back valve is driven to draw in the coating material near the tip of the die, the coating material for forming the next coating film may be discharged from the die with excessive pressure. Therefore, the film thickness of the coating start portion in the next coating film may increase.

[0005] The present disclosure has been made in view of the above-described problems, and provides a technique capable of suppressing the risk of an increase in the film thickness of the coating start portion of the coating film.

Means for Solving the Problems

[0006] The coating device according to the present disclosure is a tank for storing a coating material, a die for discharging the coating material, A first pipe connecting the die and the tank, A second pipe that branches off from the aforementioned first pipe and connects to the tank, A coating valve is provided between the branching point where the second pipe branches off from the first pipe and the die in the first piping, A circulation valve provided in the second piping, A pump located between the branching point and the tank in the first piping, In a coating apparatus comprising a suck-back valve positioned between the die and the coating valve in the first piping, The die is provided with a starting end opening valve, The system includes a third pipe connecting the aforementioned start-open valve and the aforementioned tank, The start valve is opened from the time the die begins to dispense the coating material until a predetermined period of time has elapsed.

[0007] In the coating apparatus described above, the die intermittently discharges the coating material onto a moving sheet-like body, thereby continuously forming first and second coating films with predetermined spacings on the sheet-like body. At the time when the die has finished dispensing the coating material to form the first coating film, or immediately before that, the suck-back valve performs a pull-back operation to pull the coating material in the first piping back towards the suck-back valve, The start valve is opened from the time the die begins to discharge the coating material to form the second coating film until a predetermined period of time has elapsed. [Effects of the Invention]

[0008] According to this disclosure, the risk of an increase in film thickness at the starting edge of the coating film can be suppressed. [Brief explanation of the drawing]

[0009] [Figure 1] This is a schematic diagram showing the configuration of a coating apparatus according to an embodiment. [Figure 2] It is a flowchart showing a coating method using the coating apparatus according to the embodiment. [Figure 3] It is a graph showing the film thickness with respect to the conveyance distance.

Mode for Carrying Out the Invention

[0010] Hereinafter, specific embodiments to which the present invention is applied will be described in detail with reference to the drawings. However, the present invention is not limited to the following embodiments. Also, for clarity of explanation, the following description and drawings are simplified as appropriate.

[0011] <Embodiment> Embodiment 1 will be described with reference to FIG. 1. FIG. 1 is a schematic diagram showing the configuration of the coating apparatus according to the embodiment.

[0012] Of course, the right-handed XYZ coordinates shown in FIG. 1 are for convenience in explaining the positional relationship of the components. Usually, the positive Z-axis direction is vertically upward, the XY plane is the horizontal plane, and is common among the drawings.

[0013] As shown in FIG. 1, the coating apparatus 100 includes a die coating unit 10, an intermittent coating valve unit 20, and a coating material supply unit 30.

[0014] The die coating unit 10 includes a die 11, a backup roll 12, and a start-end open valve 13.

[0015] The intermittent coating valve unit 20 includes a sack-back valve 21, a coating valve 22, and a circulation valve 23.

[0016] The coating material supply unit 30 includes a tank 31, a pump 32, and a flow meter 33.

[0017] The first pipe 1, the second pipe 2, and the third pipe 3 each connect the components of the die coating unit 10, the intermittent coating valve unit 20, and the coating material supply unit 30, respectively.

[0018] The first pipe 1 connects the die 11 and the tank 31. A sack-back valve 21, a coating valve 22, and a circulation valve 23 are provided in this order from the die 11 side to the tank 31 side in the first pipe 1.

[0019] The second pipe 2 branches from a branch point 1A between the coating valve 22 and the circulation valve 23 in the first pipe 1. The second pipe 2 connects from the branch point 1A to the tank 31. A flow meter 33 and a pump 32 are provided in this order from the branch point 1A to the tank 31 side.

[0020] The start-end open valve 13 is provided on the die 11. The third pipe 3 connects the start-end open valve 13 and the tank 31. Note that the third pipe 3 may connect the die 11 and the tank 31, and the start-end open valve 13 may be provided in the third pipe 3. When the start-end open valve 13 opens, the coating material can move from the die 11 to the third pipe 3 side. When the start-end open valve 13 closes, the coating material cannot move from the die 11 to the third pipe 3 side. The start-end open valve 13 can use, for example, a gate valve.

[0021] The backup roll 12 is a substantially cylindrical body or a substantially cylindrical tube that is rotatably held. A part of the outer peripheral surface of the backup roll 12 is wound with a sheet-like body SH. By driving the backup roll 12 to rotate, the sheet-like body SH can be moved.

[0022] The die 11 is provided so as to be able to discharge the coating material to the outer peripheral surface side of the backup roll 12. A slit for discharge is provided at the tip of the die 11. The tip of the die 11 faces the sheet-like body SH.

[0023] The tank 31 stores the coating material. The coating material is, for example, a liquid or a paste-like body. The coating material may be, for example, an electrode material of a battery.

[0024] Pump 32 uses pressure to transfer the coating material stored in tank 31 to branch point 1A. Pump 32 may be, for example, a mono pump. Flow meter 33 measures the flow rate of the coating material passing through the flow meter 33 in the second pipe 2.

[0025] The suck-back valve 21 is, for example, a roughly cylindrical piston. The suck-back valve 21 is inserted into the first pipe 1 so as to be movable from the outer diameter side toward the inside. The diameter of the part 1B in the first pipe 1 into which the suck-back valve 21 is inserted is larger than the diameter of other parts so that the suck-back valve 21 can move. The suck-back valve 21 is supplied with driving force as appropriate from a motor (not shown). The suck-back valve 21 is driven by this supplied driving force from the outside to the inside (pushing) or from the inside to the outside (pulling) of the first pipe 1. The motor receives power from, for example, an external power source and generates force to cause the suck-back valve 21 to perform pushing and pulling operations.

[0026] The coating valve 22 can control the movement of the coating material by opening and closing it. Specifically, when the coating valve 22 is open, the coating material can move from branch point 1A towards the suck-back valve 21. When the coating valve 22 is closed, the coating material cannot move from branch point 1A towards the suck-back valve 21. For example, the coating valve 22 is approximately cylindrical in shape. The coating valve 22 is provided with a hole (illustrated) that penetrates from the outer surface of the approximately cylindrical shape, through the central axis, to its end face. This hole is connected to the first piping 1. The coating valve 22 rotates with the central axis of the approximately cylindrical shape as its rotation axis, powered by a motor 42 connected to the coating valve 22. The motor 42 receives power from, for example, an external power source (not shown) to generate the rotational force necessary to rotate the coating valve 22.

[0027] The circulation valve 23 can control the movement of the coating material by opening and closing it. Specifically, when the circulation valve 23 is open, the coating material can move from branching point 1A to the tank 31. When the circulation valve 23 is closed, the coating material cannot move from branching point 1A to the tank 31. For example, the circulation valve 23 is substantially cylindrical, similar to the coating valve 22, and as shown in Figure 1, a hole 23a is provided that penetrates from the outer surface of the substantially cylindrical shape through the central axis to its end face, and the hole 23a is connected to the first pipe 1. The circulation valve 23 rotates with the central axis of the substantially cylindrical shape as its rotation axis, powered by a motor 43 connected to the circulation valve 23. The motor 43 receives power from, for example, an external power source (not shown) to generate the rotational force necessary to rotate the circulation valve 23.

[0028] The coating apparatus 100 may be equipped with a control device (not shown). This control device sends control signals to each component of the coating apparatus 100 to operate them. The components of the coating apparatus 100 include, for example, a pump 32, motors 42 and 43, a start-open valve 13, and a motor that supplies driving force to the suck-back valve 21.

[0029] <Coating Method> Next, with reference to Figure 2, the operation of the coating apparatus 100 or the coating method using the coating apparatus 100 will be described.

[0030] The coating apparatus 100 prepares for the discharge of the coating material (step ST1). Specifically, the coating valve 22 is opened while closing the start valve 13 and the circulation valve 23. The coating material can move from the tank 31 to the die 11, passing through the branching point 1A in the second pipe 2 and the first pipe 1 to the die 11 side. The suck-back valve 21 may also be pushed in.

[0031] Next, the coating apparatus 100 starts discharging the coating material (step ST2). Specifically, the pump 32, through the action of pressure, causes the coating material to flow from the tank 31 through the second pipe 2 to the branching point 1A in the first pipe 1. The coating material does not flow from the branching point 1A in the first pipe 1 back towards the tank 31. The coating material flows from the branching point 1A in the first pipe 1 back towards the die 11. The backup roll 12 rotates, and the sheet-like body SH moves. The die 11 discharges the coating material onto the moving sheet-like body SH. As a result, the coating material adheres to the sheet-like body SH. More specifically, the suck-back valve 21 may be pushed further in until a predetermined period has elapsed from the time the die 11 starts discharging the coating material. This increases the flow rate of the coating material and ensures a sufficient amount of coating material is discharged. Furthermore, the start-end open valve 13 is opened until a predetermined period of time has elapsed from the start of discharge. This allows some of the coating material remaining in the die 11 to pass through the start-end open valve 13 and the third pipe 3 and return to the tank 31.

[0032] Next, the coating apparatus 100 stops discharging the coating material (step ST3). Specifically, the coating valve 22 is closed while the circulation valve 23 is opened. The coating material does not flow from the branching point 1A in the first piping 1 to the die 11 side, but flows from the branching point 1A to the tank 31 side. The die 11 stops discharging the coating material to the sheet-like body SH. The coating material adhering to the sheet-like body SH solidifies, and the coating film C1 is formed on the sheet-like body SH. More specifically, at the time when the die 11 has finished discharging the coating material or immediately before that, the suck-back valve 21 performs a pull-back operation, pulling it back from inside the part 1B of the first piping 1 to the outside of the part 1B of the first piping 1. The coating material inside the die 11 is sucked towards the suck-back valve 21 side. Therefore, the die 11 is prevented from discharging an excessive amount of coating material. The thickness of the end of the coating film may be made uniform. Furthermore, the start-end open valve 13 is opened at the time when the die 11 has finished dispensing the coating material, or just before that. As a result, some of the coating material remaining in the die 11 passes through the start-end open valve 13 and the third pipe 3 and returns to the tank 31.

[0033] Finally, steps ST1, ST2, and ST3 are repeated until the required number of coating films are formed (step ST4: NO). In the example shown in Figure 1, a total of three coating films, C1 to C3, are formed. Once the required number of coating films are formed, this coating method is complete (step ST4: YES).

[0034] Based on the above, the required number of coating films can be manufactured. In the example shown in Figure 1, a total of three coating films, C1 to C3, are formed.

[0035] With this coating method, in step ST2, the start-end opening valve 13 is opened from the start of discharge until a predetermined period has elapsed. This allows a portion of the coating material remaining in the die 11 to pass through the start-end opening valve 13 and the third pipe 3 and return to the tank 31. This suppresses the risk of the coating thickness increasing at the starting end of the coating process.

[0036] Furthermore, in step ST3, at or immediately before the die 11 finishes discharging the coating material, the suck-back valve 21 performs a pull-back operation, pulling the material back from inside the first pipe 1 section 1B to the outside of the first pipe 1 section 1B. After this pull-back operation, the coating film C1 can be formed. Subsequently, for example, when returning to step ST2 to form the coating film C2, the suck-back valve 21 performs a push-in operation, pushing the material from the outside of the first pipe 1 section 1B into the first pipe 1 section 1B. The push-in operation of the suck-back valve 21 may cause the coating material to move towards the die 11, potentially increasing the amount of coating material discharged. However, in step ST2, by opening the start-end valve 13 from the start of discharge until a predetermined period has elapsed, a portion of the coating material remaining in the die 11 can pass through the start-end valve 13 and the third pipe 3 and return to the tank 31. This suppresses the increase in the amount of coating material dispensed, thereby preventing an increase in the film thickness at the coating start end C2a of the coating film C2.

[0037] <Examples> Next, referring to Figure 3, we will explain the results of the experiment using the coating method shown in Figure 2. Figure 3 is a graph showing the film thickness as a function of transport distance.

[0038] In this example, a coated film was formed using the coating method shown in Figure 2. The film thickness at the starting end of the formed coated film was measured, and the film thickness curve FC1 showing the measurement result is plotted in Figure 3. In Figure 3, the film thickness curve FC1 shows the film thickness against the transport distance TL. In the example shown in Figure 1, the transport distance TL corresponds to the position in the negative X-axis direction of the coated film. The transport distance TL1 corresponds to the starting end of the coated film. The transport distance TL2 corresponds to a position a predetermined distance from the starting end of the coated film toward the center of the coated film.

[0039] Incidentally, there is a coating apparatus that has the same configuration as the coating apparatus 100, except that it does not have a third pipe 3 and a start-end open valve 13. In the comparative example, a coating film was formed using a coating method with this coating apparatus. The film thickness at the starting end of the formed coating film was measured, and the film thickness curve FC9 showing the measurement result is plotted in Figure 3.

[0040] As shown in Figure 3, the film thickness curve FC1 for the example shows the measured film thickness FT1 at the transport distance TL1. From the transport distance TL1 to the maximum value of the transport distance TL, the film thickness curve FC1 for the example showed a value approximately equivalent to the measured film thickness FT1. In other words, the film thickness at the starting point of the coating of the coating film in the example is approximately constant.

[0041] The film thickness curve FC9 for the comparative example extends convexly from transport distance TL1 to transport distance TL2, showing a film thickness greater than the measured film thickness FT1. The film thickness curve FC9 for the comparative example showed a film thickness almost identical to that of film thickness curve FC1 from transport distance TL2 to the maximum value of transport distance TL.

[0042] Based on the above, the example can suppress the risk of an increase in the film thickness at the starting point of the coating compared to the comparative example.

[0043] It should be noted that the present invention is not limited to the embodiments described above, and can be modified as appropriate without departing from the spirit of the invention. Furthermore, the present invention may be implemented by combining the above embodiments or examples thereof as appropriate. [Explanation of symbols]

[0044] 100 Coating equipment 1. First piping 1A Branch point 1B part 2. Second piping 3. Third pipe 10 Die coating units 11 Dies 12 Backup Roles 13. Starting valve 20 Intermittent Coating Valve Units 21 Suck-back valve 22 Coated Valves 23 Circulation valve 30 Coating material supply unit 31 tanks 32 pumps 33 Flow meter 42, 43 Motors C1, C2, C3 coating film SH Sheet-like material Conveying distance TL1, TL2 Film thickness curves FC1, FC9 Film thickness measurement FT1

Claims

1. A tank for storing coating materials, A die for dispensing the coating material, A first pipe connecting the die and the tank, A second pipe that branches off from the first pipe and connects to the tank, A coating valve is provided between the branching point where the second pipe branches off from the first pipe and the die in the first piping, A circulation valve provided in the second piping, A pump is positioned between the branching point and the tank in the first piping, In a coating apparatus comprising a suck-back valve positioned between the die and the coating valve in the first piping, The die is provided with a starting end opening valve, The system includes a third pipe connecting the aforementioned opening valve and the tank, The start valve is opened from the time the die begins to dispense the coating material until a predetermined period of time has elapsed. Coating equipment.

2. The die intermittently discharges the coating material onto a moving sheet-like body, thereby continuously forming first and second coating films with predetermined spacings on the sheet-like body. At the time when the die has finished discharging the coating material to form the first coating film, or immediately before that, the suck-back valve performs a pull-back operation to pull the coating material in the first piping back towards the suck-back valve, The start valve is opened from the time the die begins to discharge the coating material to form the second coating film until a predetermined period of time has elapsed. The coating apparatus according to claim 1.

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