Horizontal coating apparatus and coating method using the same

Abstract

[Problem] Conventional coating devices have the problem of not being able to apply a uniform coating film over a large area. [Solution] A horizontal coating apparatus comprising a substrate mounting table, an electric actuator, a plate, a coating unit, and a transport unit, and a coating method using the same, wherein the coating unit of the coating unit comprises a coating bar, a spring, a coating holder, and a melamine sponge, the coating holder is filled with a coating liquid whose viscosity has been adjusted, and the coating liquid is contained in the melamine sponge Immersion The conveying unit is a horizontal coating device and a coating method using the same, which can advance or reverse the coating unit by sliding a linear block to which the plate is fixed on a linear guide rail by the movement of a ball screw, thereby moving the coating unit forward or backward.

Description

Technical Field

[0001] The present invention relates to a horizontal coating apparatus for uniformly coating a coating liquid on a large-sized substrate such as glass or resin, and a coating method using the same.

Background Art

[0002] There is a need to uniformly coat a thin film for a solar cell, a transparent conductive film, or a heat insulating film on a large-sized glass substrate or resin substrate. In order to form such a coating film, a slit coater having a discharge port formed of a slit that is long in the width direction has been conventionally used. The coating liquid is discharged from the discharge port onto the substrate to form a coating film of the coating liquid on the substrate.

[0003] Particularly, regarding the heat insulating film, among those that have been put into practical use so far, there is one in which a low emissivity thin film (so-called LowE film) is formed on a large-sized substrate using a physical vapor deposition method called sputtering, but a method of coating and forming a coating liquid on a large-sized substrate has not been put into practical use.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0005] The problem to be solved is that a uniform coating film of the coating liquid cannot be easily coated over a large area with a conventional coating liquid coating apparatus.

[0006] Patent Document 1 describes a coating apparatus that aims to easily change the discharge width while suppressing variations in the widthwise dimension of the coating film due to the applied coating liquid. It comprises a slit nozzle with a discharge port consisting of a slit that is long in the width direction and discharges the coating liquid from the discharge port onto the substrate; a drive unit that moves the substrate in the front-back direction relative to the slit nozzle; a discharge width changing member that changes the widthwise dimension of the discharge port by moving within the slit in the width direction; and an air supply unit which has an air nozzle that blows air onto the areas on both sides of the widthwise outer edge of the coating liquid discharged from the discharge port, and the position of the air blown by the air nozzle can be adjusted according to the change in the widthwise dimension of the discharge port. However, with this method, the film thickness on both sides of the widthwise outer edge of the substrate becomes thicker, so air must be blown by the air nozzle to adjust it.

[0007] Patent Document 2 aims to achieve a desired thickness for the coating film applied to the substrate. The coating apparatus has a reservoir for storing the coating liquid, a discharge port for discharging the coating liquid, and a slit-shaped channel connecting the reservoir and the discharge port, discharging the coating liquid from the discharge port onto the substrate. The coating apparatus includes a moving means for moving the coating apparatus in a direction parallel to the surface to be coated relative to the substrate, a pump for supplying the coating liquid to the coating apparatus, and a control device. The control device controls the supply of coating liquid from the pump to the coating apparatus while creating a negative pressure in the coating liquid inside the coating apparatus during the coating operation, which involves discharging the coating liquid from the discharge port onto the substrate while moving the coating apparatus. However, in this method, in order to achieve a desired thickness for the coating film, it is necessary to control the supply of coating liquid from the pump to the coating apparatus while creating a negative pressure in the coating liquid inside the coating apparatus.

[0008] Patent Document 3 aims to provide a coating apparatus and coating method that enables the formation of a thin coating film of uniform thickness by ensuring that a constant pressure acts on the bead during coating film formation in a capillary coating with the nozzle discharge port facing downward, and that maximizes the area of ​​uniform thickness of the product by appropriately controlling the amount of coating liquid supplied to the bead at the start and end of coating. The apparatus comprises a coating device having a coating liquid storage section, a supply channel, a discharge port, a slit-shaped channel connecting the coating liquid storage section and the discharge port, a moving means for moving the coating device, a lifting device, and a pressure applying device for applying pressure to the coating liquid in the coating device, and is equipped with a pressure gauge for measuring the pressure in the coating liquid storage section, and the pressure applying device comprises a tank, an on / off valve, a pressure actuator, and a pressure control device that controls the acting pressure of the pressure actuator based on the pressure in the coating liquid storage section. However, this apparatus requires a complex pressure control device and pressure actuator. [Means for solving the problem]

[0009] To solve the above-mentioned conventional problems, the present invention provides a substrate mounting table on which a substrate is placed, an electric actuator, a plate, a coating unit, and a transport unit, wherein the coating unit comprises a coating unit vertical cylinder and linear shaft provided at the tip of the electric actuator, and a coating unit attached to the electric actuator via the coating unit vertical cylinder, the coating unit is a unit comprising a coating bar, a coating holder, and a melamine sponge, the electric actuator is fixed to the plate, and two linear shafts provided spaced apart on both sides of the electric actuator pass through holes provided in the plate and are fixed to the coating unit to support the coating unit, and the coating The application bar and application holder of the unit are connected via a mounting bracket and a spring, the application holder is filled with a coating liquid adjusted to a viscosity of 2 to 10 cP (centipoise), the coating liquid impregnates the melamine sponge, the transport unit comprises a servo motor, a ball screw, a timing belt, a linear guide rail, and a linear block, the transport unit moves forward or backward from the plate, the application unit is attached via an electric actuator fixed to the plate and an electric actuator via a cylinder for moving the application unit up and down from the application unit, the melamine sponge impregnated with the coating liquid moves forward or backward on the substrate surface, and this is the characteristics of the horizontal coating apparatus.

[0010] Furthermore, the second invention of this application is a coating method using the horizontal coating apparatus, characterized in that a substrate is placed on the substrate placement table, the coating unit is moved downward by lowering the cylinder for vertical movement of the coating unit in response to a command from the electric actuator, the melamine sponge impregnated with a coating liquid adjusted to a viscosity of 2 to 10 cP (centipoise) at the tip of the coating unit is brought into contact with the substrate surface, the servo motor is rotated in response to a command from the electric actuator, the rotational force is transmitted to the ball screw via the timing belt, the rotational movement of the ball screw causes the linear block to which the ends of the plate on the linear guide rails on both sides of the coating unit are fixed to slide forward or backward, the plate, the electric actuator fixed to the plate, and the coating unit attached from the electric actuator via the cylinder for vertical movement of the coating unit move forward or backward on the substrate surface, and the coating liquid impregnated in the melamine sponge is applied to the substrate surface.

[0011] Figure 1 (perspective view) shows the external appearance of the horizontal coating apparatus of the present invention. It shows the state before the lower half of the linear shaft on the coating unit side is inserted into the upper half of the linear shaft on the plate side, and before the electric actuator and the cylinder for moving the coating unit up and down are coupled. At the bottom is the substrate mounting table on which the substrate is placed, and the coating unit that applies the coating liquid to the substrate set on the substrate mounting table is visible on the right. The front and back are the transport section, which contains a ball screw that converts the rotational motion of the servo motor into forward and backward motion, and the linear block that moves in conjunction with the ball screw on a linear guide rail. What is visible at the top back is a cable carrier (registered trademark) for moving the control system cables in accordance with the movement of the coating section.

[0012] Figure 2 shows a front view of the horizontal coating apparatus of the present invention. On the left side of the front view are the linear guide rail and linear block of the transport unit, and above them is a cable carrier (registered trademark) bundling the cables of the control system. On the right side of the front view is the transport unit, which includes the servo motor, the ball screw, the linear guide rail and the linear block. The plate is fixed to the linear block at its end. The central coating unit is driven up and down by the transport unit in a direction perpendicular to the paper plane, and the coating liquid is applied to the substrate on the substrate mounting table. Below the substrate mounting table, glass transport rollers and suction cups for fixing the substrate are provided so that the substrate can also be moved manually. This arrangement is a so-called gantry type, in which the transport unit is formed to straddle the coating unit.

[0013] Figure 3 shows a side view of the horizontal coating apparatus of the present invention. The substrate placement table moves the substrate using substrate transport rollers and secures the substrate with suction cups. The substrate can be manually moved back and forth and left and right on the transport rollers. The coating unit is located directly below the electric actuator, but moves from left to right in this figure together with the electric actuator by the transport unit. The cable carrier (registered trademark) moves similarly to the movement of the coating unit.

[0014] Figure 4 is a schematic diagram illustrating the details of the coating section. The coating liquid is automatically supplied from a coating liquid tank (not shown) to the coating holder 6 via a coating liquid transport pipe (not shown) by a dispenser (not shown), and impregnated into the melamine sponge 8. The melamine sponge 8, impregnated with the coating liquid, then moves along the substrate surface of the float glass 10, in a direction perpendicular to the plane of the paper in this figure, thereby applying the coating liquid to the substrate surface of the float glass 10. The thickness of the coating film is determined by the self-leveling effect of the coating liquid, whose viscosity is adjusted to 2-10 cP (centipoise), and is approximately 2 μm-5 μm. However, the amount of coating liquid discharged can also be adjusted by changing the pressure applied to the melamine sponge 8 by moving the coating unit's vertical cylinder 7 up and down with the electric actuator 1. The coating unit's vertical cylinder 7 is operated so that it is pressed firmly when a thicker coating film is desired, and lightly when a thinner coating film is desired. The coating bar 5 and coating holder 6 of the coating unit are connected by a mounting bracket 20 and a spring 9. The coating unit is supported by linear shafts 21 located on both outer sides, spaced apart from the electric actuator 1, and can slide smoothly up and down due to the action of linear bushings provided at the position where the linear shafts 21 pass through the plate 4. In Figure 4, the linear bushing is the thickened part at the position where the linear shaft 21 passes through the plate 4 in the center. The coating unit moves up and down by a coating unit vertical cylinder 7 while being supported by the linear shafts 21, and is also able to move like a pendulum, so that the coating unit (and therefore the melamine sponge) is pressed correctly perpendicularly against the substrate.The coating unit moves in the longitudinal direction of the substrate (perpendicular to the plane of the paper). This movement is caused by a signal from the electric actuator 1, which rotates the servo motor 16. The rotational force is transmitted to the ball screw 15 by a timing belt. The ball screw 15 converts the rotational force into forward and backward motion, and the linear block 2, to which the end of the plate 4 is fixed, moves along the linear guide rail 3. As a result, the coating unit moves in the forward and backward direction (perpendicular to the plane of the paper), and the melamine sponge 8 moves in the forward and backward direction on the surface of the float glass 10, applying the coating liquid to the surface of the float glass 10.

[0015] Figure 5 shows the movement of the coating unit from the side. The coating liquid is supplied from the coating liquid tank 12 through the filter 14 and the coating liquid transport pipe 13 to the coating holder 6. A melamine sponge 8 is attached to the coating holder 6 and is impregnated with the coating liquid. When a command is sent from the electric actuator 1, the servo motor 16 is activated, and the rotational force is transmitted to the ball screw 15 by the timing belt 19. The ball screw 15 has the function of converting rotational force into translational force (forward and backward motion), and when the ball screw 15 is activated, the linear block 2 to which the end of the plate 4 is fixed moves along the linear guide rail 3, left and right in this figure, causing the set of electric actuator 1, coating bar 5, coating holder 6 and melamine sponge 8 to move left and right. As a result, the coating liquid impregnated into the melamine sponge 8 is applied to the surface of the substrate (float glass 10 in this case). The pressure applied by the melamine sponge 8 to the substrate can be adjusted by the electric actuator 1 controlling the cylinder 7 for raising and lowering the coating unit (located below the electric actuator 1 and not shown in Figure 5).

[0016] Figure 6 shows a further enlarged view of the coating section. The coating unit's vertical cylinder 7 is connected to the tip of the electric actuator 1 and moves up and down according to a command from the electric actuator 1. The electric actuator 1 is fixed to the plate 4. Holes are provided on both outer sides of the electric actuator 1 on the plate 4, and the linear shaft 21 supports the coating unit through these holes, and during vertical movement, it can slide via linear bushings provided in the holes. The coating unit's vertical cylinder 7 and the linear shaft 21 are connected to the coating bar 5. The coating bar 5 consists of two parts, upper and lower, and these parts are connected by a mounting bracket 20 and four springs 9. The lower part of the coating bar 5 is reinforced by inserting a fixing bracket 22 into a recess. The coating holder 6 is fitted into the lower recess of the fixing bracket 22. The melamine sponge 8 is inserted into the coating holder 6. The two springs 9 on each side of the mounting bracket 20 can mitigate the impact when the coating unit hits the substrate. Similarly, the application unit is also capable of small pendulum-like movements due to the action of the mounting bracket 20 and the spring 9.

[0017] Figure 7 is an enlarged view of the coating holder 6. It has a U-shaped member with a projection, into which a melamine sponge 8 is inserted, and the coating liquid 17 can be supplied from the coating liquid transport pipe 13 into the resulting space. The projection is inserted into a recess provided in the fixing bracket 22 for fixing.

[0018] The total width of the coating holder 6 and the melamine sponge 8 is matched to the total width of the substrate mounting table of the horizontal coating apparatus of the present invention. The coating liquid is then applied to the entire surface of the substrate by moving the coating holder 6 and the melamine sponge 8 in the direction of the arrow in Figure 5 (the longitudinal direction of the substrate). The melamine sponge 8 may be divided into two or three pieces, but it has been confirmed that even if there are small gaps between the melamine sponges, the gaps are filled by the self-leveling function of the applied coating film, resulting in a uniform thickness overall.

[0019] Using the horizontal coating device of the present invention, a coating liquid adjusted to a viscosity of 2 to 10 cP (centipoise) is applied to a substrate horizontally placed on a substrate mounting table by means of the melamine sponge, and a film thickness determined by the self-leveling effect of the coating liquid can be applied. In this case, it is desirable to confirm that the contact angle of the coating liquid droplets on the surface of the washed substrate is in the range of 5 to 20° before applying the coating liquid. This is because the coating liquid spreads uniformly and the adhesion to the substrate increases.

Effects of the Invention

[0020] According to the present invention, a horizontal coating device capable of simply applying a uniform coating film on a substrate with a large area can be obtained, and a coating film with a large adhesion that spreads uniformly on the substrate can be applied using this device.

Brief Description of the Drawings

[0021] [Figure 1] It is a perspective view of the horizontal coating device of the present invention. [Figure 2] It is a plan view of the horizontal coating device of the present invention. [Figure 3] It is a side view of the horizontal coating device of the present invention. [Figure 4] It is a schematic diagram (front view) showing the configuration of the coating part of the horizontal coating device of the present invention. [Figure 5] It is a schematic diagram (side view) showing the configuration of the coating part of the horizontal coating device of the present invention. [Figure 6] It is an enlarged view of the coating part of the horizontal coating device of the present invention. [Figure 7] It is an enlarged view of the coating holder of the horizontal coating device of the present invention.

Modes for Carrying Out the Invention

[0022] The horizontal coating device of the present invention has the configuration and functions described so far using FIGS. 1 to 7. Based on the following examples, the configuration, functions, and coating method of the horizontal coating device of the present invention will be described again.

Examples

[0023] A 3mm thick float glass (FL3) measuring 900mm wide x 1200mm long was cleaned using an abrasive (cerium oxide), then brushed with a neutral detergent, rinsed with pure water, dried with an air knife, and then set in the substrate input section of the substrate mounting table of the horizontal coating machine.

[0024] The horizontal coating apparatus of the present invention has the function of applying a coating solution impregnated into a melamine sponge 8 to the entire surface of glass, and has a structure that allows the coating speed, coating operation mode (one-way coating or back-and-forth coating), etc. to be set via a touch panel.

[0025] The 3mm thick float glass substrate, placed on the substrate mounting table, was manually transported to its designated position on the transport rollers, positioned against the guide, and then the transport rollers were lowered. Finally, the glass substrate was attached using suction cups to complete the setup process.

[0026] As preparation for coating, the coating liquid 17 was supplied from the coating liquid tank 12 to the coating holder 6, which was fitted with melamine sponges 8, and the holder was left on standby. The total coating width of the horizontal coating device used in this embodiment is 900 mm, but in this embodiment, three rows of 299 mm long melamine sponges were joined together and mounted on the coating holder 6 to make it 900 mm. There was a gap of up to approximately 1.5 mm at the joints of the melamine sponges.

[0027] The coating bar 5, coating holder 6, and melamine sponge 8 were assembled into a single unit as shown in Figures 4 and 6, and reinforced with a mounting bracket 20. The assembled coating unit was then mounted on the coating unit up / down cylinder 7 at the tip of the electric actuator 1. The electric actuator 1 was fixed to the plate 4. It was confirmed that the coating unit up / down cylinder 7 could be freely moved up and down by pushing or pulling the coating unit up by a distance of approximately 5 cm in response to a command from the electric actuator 1.

[0028] Next, as shown in Figure 5, it was confirmed that by rotating the servo motor 16 in response to a command from the electric actuator 1, and transmitting the rotational force to the ball screw 15 via the timing belt 19, the ball screw rotates clockwise, causing the linear block 2, to which the end of the plate 4 is fixed, to slide forward on the linear guide rails 3 located on both sides of the coating unit, thereby causing the plate 4, the electric actuator 1 fixed to the plate, and the coating unit attached to the electric actuator 1 via the coating unit's vertical movement cylinder 7 to move forward.

[0029] Next, the coating unit was returned to the starting point of coating the float glass 10. Then, a command was sent from the electric actuator 1 to the coating unit's vertical movement cylinder 7 to lower the coating unit, bring it into contact with the surface of the float glass 10, and then press it down with a pressing pressure of 50N.

[0030] Next, by sending a command from the electric actuator to the servo motor, the coating unit was moved forward along the surface of the float glass 10 from the coating starting point, allowing the melamine sponge 8 to apply the coating liquid to the float glass surface. The coating was completed by stopping the movement of the coating unit at the rear end of the float glass 10. The pressure of the melamine sponge 8 against the surface of the float glass 10 was set to 50N, and at this time, the cylinder 7 for moving the coating unit up and down descended 1.0 mm after contacting the surface of the float glass 10. The coating speed (coating unit travel speed) during coating was 100 mm / s, and the coating was performed in one direction.

[0031] The coating condition at the seams of Melamine Sponge 8 showed some discoloration immediately after application due to the low amount of coating liquid. However, after approximately 20 seconds, the discoloration disappeared. This is thought to be because the self-leveling effect of the coating liquid worked to make the thickness of the coating film uniform.

[0032] The heat-shielding coating liquid (product name: C5000) used in this example had a viscosity of 7 cP (centipoise). When a droplet was dropped onto a glass substrate after cleaning, the contact angle after 1 second was 18.4°, but after 28 seconds it decreased to 13.4°, indicating that the wettability of the coating liquid to the glass had improved and the self-leveling effect had progressed.

[0033] Immediately after application, the coating was liquid, but after heating with an infrared heater at 100°C for 10 minutes and then allowing it to air dry for one day, the coating had almost completely hardened. The resulting coating was a transparent, slightly blue heat-shielding glass with no color unevenness or discoloration, and micron-sized sparkling specks caused by dust or foreign matter were hardly noticeable. The light transmittance of the heat-shielding glass coated with this heat-shielding liquid was 0.7% for ultraviolet light transmittance, 79% for infrared light cut rate, and 79% for visible light transmittance. There was almost no variation within the surface, indicating that the coating was applied with a uniform film thickness.

[0034] In this embodiment, the coating solution was applied to the float glass substrate using a melamine sponge. However, for resin substrates that are softer than float glass substrates, a urethane sponge can be used instead of a melamine sponge. [Explanation of Symbols]

[0035] 1. Electric Actuator 2. Linear Block 3. Linear guide rail 4.. Plate 5. Application bar 6. Application holder 7. Upper and lower cylinders for the coating unit. 8. Melamine sponge 9.. Spring 10. Substrate (float glass) 11. Glass transport roller with glass suction cup 12. Coating liquid tank 13. Coating liquid transport pipe 14.. Filter 15. Ball screw 16. Servo motor 17. Coating liquid 18. Cable Bear (registered trademark) 19. Timing belt 20... Mounting bracket 21. Linear shaft 22... Fixing bracket

Claims

1. The apparatus comprises a substrate mounting table for placing substrates, an electric actuator, a plate, a coating unit, and a transport unit. The coating unit comprises a coating unit vertical cylinder and linear shaft provided at the tip of the electric actuator, and a coating unit attached to the electric actuator via the coating unit vertical cylinder. The coating unit comprises a coating bar, a coating holder, and a melamine sponge. The electric actuator is fixed to the plate, and two linear shafts spaced apart on both sides of the electric actuator pass through holes provided in the plate and are fixed to the coating unit to support the coating unit, and the coating unit... A horizontal coating apparatus characterized in that the bar and the coating holder are connected via a mounting bracket and a spring, the coating holder is filled with a coating liquid adjusted to a viscosity of 2 to 10 cP (centipoise), the coating liquid impregnates the melamine sponge, the transport unit comprises a servo motor, a ball screw, a timing belt, a linear guide rail, and a linear block, the transport unit moves forward or backward the coating unit, which is attached to the plate and the plate via an electric actuator fixed to the plate and an electric actuator via a cylinder for moving the coating unit up and down, so that the melamine sponge impregnated with the coating liquid moves forward or backward on the surface of the substrate.

2. A coating method using the horizontal coating apparatus described in claim 1, characterized in that a substrate is placed on the substrate placement table, the coating unit is moved downward by lowering the cylinder for vertical movement of the coating unit in response to a command from the electric actuator, the melamine sponge impregnated with a coating liquid adjusted to a viscosity of 2 to 10 cP (centipoise) at the tip of the coating unit is brought into contact with the surface of the substrate, the servo motor is rotated in response to a command from the electric actuator, the rotational force is transmitted to the ball screw via the timing belt, the rotational motion of the ball screw causes the linear block, to which the ends of the plate on the linear guide rails on both sides of the coating unit are fixed, to slide forward or backward, so that the plate, the electric actuator fixed to the plate, and the coating unit attached from the electric actuator via the cylinder for vertical movement of the coating unit move forward or backward on the surface of the substrate, thereby coating the surface of the substrate with the coating liquid impregnated in the melamine sponge.

3. The coating method according to claim 2, wherein the coating liquid is applied to the surface of a substrate placed horizontally on the substrate mounting table using the melamine sponge, and a film thickness determined by the self-leveling effect of the coating liquid is applied.

4. The coating method according to claim 2, wherein before applying the coating liquid, it is confirmed that the contact angle of the droplets of the coating liquid on the cleaned substrate surface is in the range of 5 to 20°, and then the coating liquid is applied.

Images