Coating apparatus and coating method
Patent Information
- Application Number
- PCT/JP2025/043116
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2025-02-18
- Filing Date
- 2025-12-10
- Publication Date
- 2026-08-27
Smart Images
Figure JP2025043116_27082026_PF_FP_ABST
Abstract
Description
Coating apparatus and coating method
[0001] The present invention relates to a coating apparatus and a coating method. More specifically, the present invention relates to a coating apparatus and a coating method for forming a coating film of uniform thickness on a substrate to be coated.
[0002] Coating technology for forming functional coatings on substrates such as films, metal foils, paper, textiles, nonwoven fabrics, reinforcing fibers, and glass is used in a wide range of fields, including functional films, paper products, fabric products, film products, batteries, electrical appliance components, semiconductor components, and composite material components. In particular, for applications requiring uniformity of coating film thickness, die coating methods using a die head (slit die, slot die) with a manifold, slit-shaped flow channels, and slit-shaped discharge ports are preferably employed.
[0003] In die coating, it is desirable to maintain a constant gap (coating clearance) between the tip of the die head with the discharge port and the substrate in order to form a coating film of uniform thickness on the substrate. However, this coating clearance often becomes uneven during coating. Therefore, if the coating liquid is applied to the substrate with an uneven coating clearance, a coating film of uniform thickness cannot be obtained, and sometimes coating defects or poorly coated areas occur. There are two main reasons for this. The first is the effect of waviness on the surface of the support stand that supports the substrate to be coated, or the surface of the chuck stand that holds the substrate. This can be improved by machining the surface with high precision. However, in the case of large substrates, a wide flat surface must be machined with high precision, which makes the cost extremely high. The second is the effect of warping, waviness, and thickness variations in the substrate to be coated. Due to this effect, even if the surface of the support stand or chuck stand is machined with high precision to form an extremely precise flat surface, the coating clearance becomes uneven because the surface height of the substrate itself is not uniform.
[0004] As a method for solving the problem that this coating clearance becomes non-uniform during coating and forming a coating film with a uniform film thickness on a substrate, Patent Document 1 discloses a method of suspending a die head with a plurality of springs with the die head tip facing downward, discharging a coating liquid from the die head tip in a state where the die head tip is substantially in contact with the substrate, and applying the coating liquid to the substrate.
[0005] Also, as another embodiment in Patent Document 1, a chuck table that supports a substrate is configured to be supported by a plurality of springs or cushions and can be freely pushed down, and a method of discharging a coating liquid from the die head tip in a state where the die head tip is substantially in contact with the substrate and applying the coating liquid to the substrate is also disclosed.
[0006] Japanese Patent Application Laid-Open No. 2007-313416
[0007] However, the method disclosed in Patent Document 1 cannot keep the coating clearance constant depending on the warping and undulating directions of the substrate and the distribution of thickness unevenness of the substrate, and a coating film with a uniform film thickness cannot be formed on the substrate. For example, when the substrate has thickness unevenness that undulates in the coating width direction, the die head is lifted or the chuck table is pushed down based on the convex portion of the substrate due to the hydraulic pressure of the coating liquid between the die head and the substrate, and the coating clearance in the coating width direction does not become constant. Therefore, when the coating liquid is applied to the substrate in that state, a coating film with a uniform film thickness is not formed, and sometimes coating defects and coating defective parts may occur.
[0008] The present invention has been made in view of these conventional problems, and an object thereof is to provide a coating apparatus and a coating method that can form a coating film with a uniform film thickness and is less likely to cause coating defects and coating defective parts even for a substrate having warping, undulating, and thickness unevenness.
[0009] A coating apparatus according to one aspect of the present invention, which solves the above problems, is a coating apparatus for applying a coating liquid to a substrate, comprising: a support; an elastic body supported by the support and for supporting the substrate while in contact with it; a die head having a tip portion in which a discharge port for discharging the coating liquid is formed, for discharging the coating liquid to the substrate supported by the support; and a moving mechanism for moving the die head along the surface of the substrate relative to the substrate.
[0010] Furthermore, an application method according to one aspect of the present invention that solves the above problems is an application method in which the application liquid is applied to the substrate supported while in contact with the elastic body using the application apparatus, wherein the application liquid is discharged from the discharge port of the tip to the substrate, the liquid pressure from the application liquid applied between the tip and the substrate pushes the substrate to the elastic body, and the application liquid is applied to the substrate by moving the die head relative to the substrate without the tip contacting the substrate.
[0011] Figure 1 is a schematic diagram of a coating apparatus in Embodiment 1 of the present invention. Figure 2 is a schematic cross-sectional view of the die head as seen from the X direction shown in Figure 1. Figure 3 is a schematic cross-sectional view of the coating apparatus of Figure 1 as seen from the X direction at the start of coating. Figure 4 is a schematic cross-sectional view of the coating apparatus of Figure 3 as seen from the Y direction. Figure 5 is a schematic cross-sectional view of the tip of the die head of Figure 3 during coating. Figure 6 is a schematic cross-sectional view showing the state of the die head and substrate of Figure 4 during coating. Figure 7 is a schematic cross-sectional view of a coating apparatus in Embodiment 2 of the present invention. Figure 8 is a schematic cross-sectional view showing the coating apparatus of Figure 7 at the start of coating. Figure 9 is a schematic cross-sectional view of the tip of the die head of Figure 8 during coating. Figure 10 is a detailed cross-sectional view of a die head with a stepped tip. Figure 11 is a schematic cross-sectional view of a coating apparatus in Embodiment 3 of the present invention. Figure 12 is a schematic cross-sectional view showing the coating apparatus of Figure 11 at the start of coating. Figure 13 is a schematic cross-sectional view of the tip of the die head with a stepped tip during coating. Figure 14 is a schematic diagram of a coating apparatus in Embodiment 4 of the present invention. Figure 15 is a schematic cross-sectional view of the coating apparatus shown in Figure 14, viewed from the X direction, at the start of coating. Figure 16 is a schematic cross-sectional view of the coating apparatus shown in Figure 15, viewed from the Y direction. Figure 17 is a schematic cross-sectional view of the tip of the die head shown in Figure 15 during coating, magnified. Figure 18 is a schematic cross-sectional view showing the state of the die head and substrate shown in Figure 16 during coating.
[0012] Preferred embodiments of the present invention are described below. The following description is illustrative of embodiments of the invention, and the present invention is not limited thereto. Various modifications can be made without departing from the purpose and effects of the present invention.
[0013] [Embodiment 1] The coating apparatus of this embodiment (Embodiment 1) is a coating apparatus for applying a coating liquid to a substrate. The coating apparatus comprises a support, an elastic body supported by the support and for supporting the substrate, a die head having a tip portion with a discharge port formed therein for discharging the coating liquid, for discharging the coating liquid to the substrate supported by the support, and a moving mechanism for moving the die head along the surface of the substrate relative to the substrate.
[0014] Furthermore, the coating method of this embodiment (Embodiment 1) is a coating method in which a coating liquid is applied to a substrate using the coating apparatus of this embodiment. In this coating method, the coating liquid is discharged from the discharge port of the tip onto the substrate, and the substrate is pressed into the elastic body by the liquid pressure created by the coating liquid applied between the tip and the substrate, while the coating liquid is applied to the substrate by moving the die head relative to the substrate without the tip touching the substrate. Each of these will be explained below.
[0015] Figure 1 is a schematic diagram showing a coating apparatus 100 in Embodiment 1 of the present invention. The coating apparatus 100 has an elastic body 2 that supports the substrate 1 to be coated in contact with it, and a support base 3 (an example of a support) as a mechanism to support the elastic body 2. Furthermore, the coating apparatus 100 includes a die head 4 with a discharge port 44 for discharging the coating liquid formed at its tip 45, and a moving mechanism 5 for moving the die head 4 relative to the surface of the substrate 1.
[0016] The elastic body 2 is provided so as to be able to press the substrate 1 when applying the coating liquid to the substrate 1. The elastic body 2 is not particularly limited. For example, the elastic body 2 is made of materials such as sponge, cushion, rubber, urethane, porous material, coil spring, or elastomer, which deform when an external force is applied and return to their original shape when the external force is removed. In this embodiment, the elastic body 2 made of silicone rubber sponge is exemplified. The hardness (spring constant) of the elastic body 2 is not particularly limited. The hardness of the elastic body 2 can be determined by considering the thickness and rigidity of the substrate 1, as well as the magnitude of waviness and curvature.
[0017] The shape and dimensions of the elastic body 2 are not particularly limited. In this embodiment, a substantially rectangular parallelepiped-shaped elastic body 2 is exemplified. In this embodiment, the dimensions of the elastic body 2 are slightly larger than the base material 1 and slightly smaller than the upper surface of the support base 3.
[0018] The support base 3 is a member that supports the elastic body 2. The shape and dimensions of the support base 3 are not particularly limited. In this embodiment, the support base 3 is substantially rectangular, and the dimensions of its upper surface are slightly larger than those of the elastic body 2.
[0019] As shown in Figure 1, a moving mechanism 5 is attached to the upper surface of the support base 3. The moving mechanism 5 is a component provided on the upper surface of the support base 3 so as to be movable, and is a component for moving the die head 4 relative to the base material 1. The moving mechanism moves along a rail portion 31 provided on the edge of the support base 3. Specifically, the support base 3 consists of two legs 51 provided in the vertical direction and a connecting portion 52 that connects the two legs. A holding portion 53 for suspending the die head 4 extends from the lower surface of the connecting portion 52, and the die head 4 is attached to the lower end of the holding portion 53. As the legs 51 move along the rail portion 31, the tip portion 45 of the die head 4, which will be described later, moves along the upper surface of the base material 1. The driving of the moving mechanism 5 can be controlled by a control mechanism, etc., which is not shown.
[0020] The base material 1 is not particularly limited. For example, the base material 1 may be a film, metal plate, paper, textile, nonwoven fabric, fiber-reinforced plastic plate, wood, glass, semiconductor substrate, etc. In this embodiment, a base material 1 made of carbon fiber is provided as an example.
[0021] Figure 2 is a schematic cross-sectional view of the die head 4 as seen from the X direction shown in Figure 1. Inside the die head 4, there is a coating liquid inlet 41 into which the coating liquid flows, a manifold 42 for widening the incoming coating liquid in the width direction (X direction in Figure 1), and a slit-shaped flow channel 43 for straightening the coating liquid. By using a die head having a widening space and a straightening flow channel inside in this way, a uniform amount of coating liquid in the width direction can be discharged from the tip of the die head.
[0022] Next, the coating operation of the coating device 100 will be described. Figure 3 is a schematic cross-sectional view of the coating device 100 as seen from the X direction in Figure 1 at the start of coating. In Figure 3, the substrate 1 has undulations on its surface due to thickness variations. Figure 4 is a schematic cross-sectional view of the coating device 100 as seen from the Y direction in Figure 3. In Figure 4, the substrate 1 has undulations on its surface due to thickness variations. At the start of coating, the tip 45 of the die head 4 and the substrate 1 are in close proximity but not in contact.
[0023] Next, when the coating liquid is supplied to the die head 4, the coating liquid is discharged from the discharge port 44 (see Figure 2) at the tip 45 of the die head 4. At this time, the coating apparatus 100 of this embodiment drives the moving mechanism 5 to move the die head 4 along the surface of the substrate 1. As a result, the coating apparatus 100 applies the coating liquid to the substrate 1. Figure 5 is a schematic cross-sectional view of the tip 45 of the die head 4 during coating. A bead 6 (liquid reservoir) is formed between the tip 45 of the die head 4 and the substrate 1 by the discharged coating liquid. The liquid pressure from this bead 6 acts on the substrate 1, and the substrate 1 is pushed into the elastic body 2, thereby forming a coating clearance D. The hardness of the elastic body 2 is preferably such that the liquid pressure from the bead 6 between the tip 45 of the die head 4 and the substrate 1 generates a reaction force sufficient to push the substrate 1 into the elastic body 2. In this state, by using the moving mechanism 5 to move the die head 4 relative to the substrate 1 in the direction of arrow A without the tip 45 contacting the substrate 1, the substrate 1 is pressed into the elastic body 2 by the action of the hydraulic pressure of the bead 6, and the coating liquid is applied while maintaining a constant coating clearance D. Specifically, in areas where the surface of the substrate 1 is convex, the substrate 1 can be pressed deeply into the elastic body 2. On the other hand, in areas where the surface of the substrate 1 is concave, the substrate 1 can be pressed shallowly into the elastic body 2. As a result, the coating clearance D can be kept constant regardless of the surface shape of the substrate 1.
[0024] Figure 6 is a schematic cross-sectional view showing the state of the die head 4 and substrate 1 during coating. During coating, a bead 6 is formed between the tip 45 of the die head 4 and the substrate 1 by the discharged coating liquid. The substrate 1 is pressed into the elastic body 2 by the action of the liquid pressure of the bead 6, so as to maintain a constant coating clearance D. Specifically, in areas where the surface of the substrate 1 is convex, the substrate 1 may be pressed deeply into the elastic body 2. On the other hand, in areas where the surface of the substrate 1 is concave, the substrate 1 may be pressed shallowly into the elastic body 2. As a result, the coating clearance D can be kept constant in the coating width direction (the direction perpendicular to the direction of travel of the die head 4), regardless of the surface shape of the substrate 1.
[0025] Thus, according to the coating apparatus and coating method of this embodiment, even if the substrate has uneven thickness, the coating liquid can be applied while maintaining a constant coating clearance in the coating direction and coating width direction. As a result, according to the coating apparatus and coating method of this embodiment, a coating film with a uniform thickness can be formed.
[0026] This embodiment shows a case where the substrate 1 has uneven thickness. In contrast, the coating apparatus and coating method of this embodiment maintain a constant coating clearance even when the substrate 1 has warping, undulation, wrinkles, or lifting, because the bead 6 presses the substrate 1 into the elastic body 2. As a result, the coating apparatus and coating method of this embodiment can form a coating film of uniform thickness regardless of the warping, undulation, or uneven thickness of the substrate.
[0027] [Embodiment 2] The coating apparatus of this embodiment (Embodiment 2) is a coating apparatus described above in relation to Embodiment 1, and further comprises a pressing mechanism for pressing the tip of the die head against the substrate.
[0028] Furthermore, the coating method of this embodiment (Embodiment 2) is a coating method in which a coating liquid is applied to a substrate using the coating apparatus of this embodiment. In the coating method, at the start of coating, the tip of the die head is pressed against the substrate by the pressing mechanism to push the substrate into the elastic body, and then the coating liquid is discharged from the discharge port of the tip onto the substrate, and the substrate is pushed into the elastic body by the hydraulic pressure of the coating liquid applied between the tip and the substrate, and the coating liquid is applied to the substrate by moving the die head relative to the substrate without the tip touching the substrate.
[0029] The following describes each of these aspects. In the following description, components similar to those in Embodiment 1 will be denoted by the same reference numerals, and their descriptions will be omitted as appropriate.
[0030] Figure 7 is a schematic cross-sectional view of the coating apparatus 110 in this embodiment. The coating apparatus 110 includes a pressing mechanism 7 for pressing the tip 45 of the die head 4 against the substrate 1. Figure 7 illustrates a substrate 1 that is curved.
[0031] The pressing mechanism 7 is a component attached to the upper surface of the connecting portion 52 of the moving mechanism 5. The pressing mechanism 7 is held in a drivable position in a desired direction by a control mechanism (not shown) or the like. The pressing mechanism 7 pushes the upper surface of the connecting portion 52 downward in the vertical direction. As a result, the pressing mechanism 7 can press the tip portion 45 of the die head 4 against the base material 1.
[0032] Figure 8 is a schematic cross-sectional view showing the coating apparatus 110 at the start of coating. The coating apparatus 110 moves the die head 4 to the coating start position using the moving mechanism 5, and then presses the die head 4 toward the substrate 1 using the pressing mechanism 7. As a result, the tip 45 of the die head 4 pushes the substrate 1 into the elastic body 2. The amount of pushing at this time is appropriately determined according to the thickness, rigidity, and degree of warping of the substrate 1, the coating film thickness, and the thickness and hardness of the elastic body 2 used. For example, the amount of pushing is preferably about 0.1 to 10 mm, and more preferably 0.5 to 5 mm, based on the position where the back surface of the substrate 1 and the elastic body 2 come into contact before pushing.
[0033] Next, when the coating liquid is supplied to the die head 4, the coating liquid is discharged from the discharge port 44 (see Figure 2) at the tip 45 of the die head 4. At this time, the coating apparatus 110 of this embodiment drives the moving mechanism 5 to move the die head 4 along the surface of the substrate 1. As a result, the coating apparatus 110 applies the coating liquid to the substrate 1.
[0034] Figure 9 is a schematic cross-sectional view of the tip 45 of the die head 4 during coating. A bead 6 (liquid reservoir) is formed between the tip 45 of the die head 4 and the substrate 1 by the discharged coating liquid. The liquid pressure from this bead 6 acts on the substrate 1, pushing the substrate 1 into the elastic body 2, thereby forming a coating clearance D. The hardness of the elastic body 2 is preferably such that the liquid pressure from the bead 6 between the die head tip and the substrate exerts a reaction force sufficient to push the substrate 1 into the elastic body 2. In this state, when the die head 4 is moved relative to the substrate 1 in the direction of arrow A using the moving mechanism 5 without the tip 45 contacting the substrate 1, the substrate 1 is pushed into the elastic body 2 by the liquid pressure of the bead 6, and the coating liquid is applied while the coating clearance D is maintained at a constant level. Specifically, in areas where the surface of the substrate 1 is convex, the substrate 1 may be pushed deeply into the elastic body 2. On the other hand, in areas where the surface of the substrate 1 is concave, the substrate 1 can be shallowly pressed into the elastic body 2. As a result, the coating clearance D can be kept constant regardless of the surface shape of the substrate 1.
[0035] In the coating width direction as well, the coating clearance D can be kept constant, similar to Figure 6 of Embodiment 1 described above.
[0036] [Embodiment 3] Embodiment 2 illustrates the case where the tip of the die head is substantially flat. Alternatively, the tip of the die head may not be substantially flat, but may have a contact portion where a contact surface is formed that is pressed against the substrate, and a non-contact portion where a non-contact surface is formed that does not come into contact with the substrate when the contact surface is pressed against the substrate. In this case, the discharge port may be formed in the non-contact portion.
[0037] The coating apparatus 120 of this embodiment has the same configuration as the coating apparatus 110 (see Figure 7), except that it is equipped with a die head 8 with a stepped tip instead of the die head 4 (see Figure 7). Figure 10 is a detailed cross-sectional view of the die head 8 with a stepped tip of this embodiment. Figure 11 is a schematic cross-sectional view of the coating apparatus 120 of this embodiment.
[0038] As shown in Figures 10 and 11, the tip portion 80 of the die head 8 with a stepped tip has a contact portion 81 in which a contact surface 81a is formed that is pressed against the substrate 1, and a non-contact portion 82 in which a non-contact surface 82a is formed that does not come into contact with the substrate 1 when the contact surface 81a is pressed against the substrate 1. Specifically, the tip portion 80 of the die head 8 with a stepped tip is formed such that the non-contact surface 82a is positioned away from the substrate 1 by a step H relative to the contact surface 81a. The discharge port 83 is formed in the non-contact portion 82.
[0039] The coating apparatus 120 of this embodiment presses the substrate 1 into the elastic body 2 in advance using the pressing mechanism 7, so that even if the substrate 1 has significant warping, undulation, or thickness variations, the substrate 1 can be reliably pressed into the elastic body 2. Specifically, if the amount of warping, undulation, or thickness variations in the substrate 1 is greater than the thickness of the coating film to be formed, the method described above in relation to Embodiment 1 may make it difficult to maintain the liquid pressure of the bead 6 in the parts of the substrate 1 surface that are concave (see Figure 5). In such cases, it is preferable to use the coating apparatus 120 of this embodiment.
[0040] In this embodiment, it is preferable that the amount of the step H at the tip of the die head 8 with a step at the tip be the same as or slightly larger than the thickness of the coating film to be formed on the substrate. Specifically, it is preferable that it be 0.8 to 2 times the thickness of the coating film, and more preferably 1 to 1.5 times. Furthermore, from the viewpoint of forming a coating film with a uniform thickness in the coating width direction, it is preferable that the amount of the step H be uniform in the width direction of the die head 8 with a step at the tip.
[0041] Next, the coating operation by the coating device 120 will be described. Figure 12 is a schematic cross-sectional view showing the coating device 120 at the start of coating. After moving the die head 8 with a stepped tip using the moving mechanism 5 to the coating start position, the die head 8 with a stepped tip is pressed towards the substrate 1 using the pressing mechanism 7. The tip 80 of the die head 8 with a stepped tip pushes the substrate 1 into the elastic body 2. The amount of pushing at this time can be appropriately determined depending on the thickness, rigidity, and curvature of the substrate 1, the coating film thickness, and the thickness and hardness of the elastic body 2 used. For example, the amount of pushing is preferably about 0.1 to 10 mm, and more preferably 0.5 to 5 mm, based on the position where the back surface of the substrate 1 and the elastic body 2 come into contact before pushing.
[0042] Next, when the coating liquid is supplied to the die head 8 with a stepped tip, the coating liquid is discharged from the discharge port 83 at the tip portion 80 of the die head 8 with a stepped tip. At this time, the coating apparatus 120 of this embodiment drives the moving mechanism 5 to move the die head 8 with a stepped tip along the surface of the substrate 1. As a result, the coating apparatus 120 applies the coating liquid to the substrate 1. Figure 13 is an enlarged schematic cross-sectional view of the tip portion 80 of the die head 8 with a stepped tip during coating. The coating liquid discharged from the die head 8 with a stepped tip forms a bead 6 between the non-contact surface 82a of the tip portion 80 of the die head 8 with a stepped tip and the substrate 1. In this state, when the die head 8 with a stepped tip is moved relative to the substrate 1 in the direction of arrow A using the moving mechanism 5 (i.e., so that the position of the contact portion 81 is downstream in the direction of movement from the position of the non-contact portion 82), the coating film is formed while the contact surface 81a is in contact with the substrate 1 and the substrate 1 is pressed into the elastic body 2.
[0043] In this embodiment, the coating device 120 can mechanically press the base material 1 into the elastic body 2 by means of the pressing mechanism 7 (see FIG. 12) and the die head 8 with a tip step, and make the surface of the base material 1 conform to the contact surface 81a of the die head 8 with a tip step. The coating clearance D at this time, that is, the gap in which the bead 6 is formed, is equal to the amount of the step H. That is, by making the step H uniform in the coating width direction (the direction perpendicular to the advancing direction of the die head 8 with a tip step), the coating device 120 can apply the coating liquid to the base material 1 while keeping the coating clearance D constant even when the base material 1 has warpage, undulation, or thickness unevenness. As a result, according to the coating device and the coating method of this embodiment, a coating film with a more uniform film thickness can be formed.
[0044] The coating device 120 of this embodiment mechanically presses the base material 1 into the elastic body 2. Therefore, the coating device 120 is preferably applied when the rigidity of the base material 1 is high. Specifically, the coating device 120 of this embodiment is preferably applied when the rigidity of the base material 1 is relatively large with respect to the hydraulic pressure of the bead 6 generated in Embodiments 1 to 2, and the base material 1 cannot be made to conform to the tip of the die head only by the hydraulic pressure. For example, when the viscosity of the coating liquid is low, the coating speed is slow, or the film thickness of the coating film is thin, the hydraulic pressure of the bead 6 becomes low. In such cases, the coating device 120 and the coating method of this embodiment are suitable.
[0045] The coating device and the coating method of this embodiment can apply the coating liquid to the base material while keeping the coating clearance D constant for any combination of the coating film and the base material having any physical properties, and can form a coating film with a more uniform film thickness.
[0046] In addition, in the present embodiment, the case where the tip step die head 8 having the tip portion 80 including the contact portion 81 formed with the contact surface 81a pressed against the base material 1 and the non-contact portion 82 formed with the non-contact surface 82a not contacting the base material 1 when the contact surface 81a is pressed against the base material 1 is illustrated. Instead of this, in the present embodiment, a die head formed with a contact portion and a non-contact portion may be used regardless of the step. For example, such a modified die head has an inclined surface at the tip portion, and thereby may have a portion pressed against the base material (contact portion having a contact surface) and a portion separated from the base material (non-contact portion having a non-contact surface). In this case, a coating film having a desired thickness can be formed by appropriately adjusting the inclination ratio of the inclined surface.
[0047] [Embodiment 4] The coating apparatus of the present embodiment (Embodiment 4) is the coating apparatus 100 described above in relation to Embodiment 1, and includes a roller covered with an elastic body instead of the support base 3 and the elastic body 2 (see FIG. 1).
[0048] FIG. 14 is a schematic view showing the coating apparatus 130 in Embodiment 4 of the present invention. The coating apparatus 130 includes an elastic roller 10 that supports the base material 1 to be coated so as to contact it.
[0049] The elastic roller 10 is composed of a roller main body portion 10A and an elastic body 10B that covers the roller main body portion 10A. The elastic roller 10 is rotatably held along the conveyance direction of the base material. Conveyor rollers 9 are provided on the upstream side and the downstream side of the elastic roller 10, respectively.
[0050] The elastic roller 10 is a long columnar member provided so as to be able to push the base material 1 when applying the coating liquid to the base material 1.
[0051] The material constituting the roller main body portion 10A is not particularly limited. For example, the material constituting the roller main body portion 10A is steel, stainless steel, aluminum, or the like. In the present embodiment, the case where the roller main body portion 10A is made of stainless steel is illustrated.
[0052] The length of the roller main body portion may be longer than the width of the base material.
[0053] The material constituting the elastic body 10B is not particularly limited. For example, the material constituting the elastic body 10B is preferably a material that deforms when an external force is applied and returns to its original shape when the external force is removed, and is more preferably a sponge, cushion, rubber, urethane, porous material, coil spring, or elastomer. The surface hardness of the elastic body 10B is not particularly limited. The surface hardness of the elastic body 10B can be appropriately determined considering the thickness and rigidity of the base material 1, as well as the magnitude of waviness and warping.
[0054] Next, the coating operation of the coating device 130 will be described. Figure 15 is a schematic cross-sectional view of the coating device 130 as seen from the X direction in Figure 14 at the start of coating. The substrate 1 has undulations on its surface due to thickness variations. Figure 16 is a schematic cross-sectional view of the coating device 130 as seen from the Y direction in Figure 15. In Figure 16, the substrate 1 has undulations on its surface due to thickness variations. At the start of coating, the tip 45 of the die head 4 and the substrate 1 are in close proximity but not in contact.
[0055] First, the substrate 1 is transported in the direction of arrow B shown in Figure 15 so that it is in contact with the transport roller 9 and the elastic roller 10. Next, when the coating liquid is supplied to the die head 4, the coating liquid is discharged from the discharge port 44 at the tip 45 of the die head 4. At this time, the coating apparatus 130 of this embodiment drives the moving mechanism 5 to move the die head 4 to the surface of the substrate 1. As a result, the coating apparatus 130 applies the coating liquid to the transported substrate 1. Figure 17 is a schematic cross-sectional view of the tip 45 of the die head 4 during coating. The substrate 1 is transported in the direction of arrow B. A bead 6 is formed between the tip 45 of the die head 4 and the substrate 1 by the discharged coating liquid. The liquid pressure from this bead 6 acts on the substrate 1, and the substrate 1 is pushed into the elastic roller 10, thereby forming a coating clearance D. Preferably, the elastic roller 10 is hard enough to exert a reaction force sufficient to push the substrate 1 into the elastic roller 10 due to the hydraulic pressure of the bead 6 located between the tip 45 of the die head 4 and the substrate 1. At this time, the substrate 1 is pressed into the elastic roller 10 by the action of the hydraulic pressure of the bead 6, and the coating liquid is applied while maintaining a constant coating clearance D. Specifically, in areas where the surface of the substrate 1 is convex, the substrate 1 can be pressed deeply into the elastic roller 10. On the other hand, in areas where the surface of the substrate 1 is concave, the substrate 1 can be pressed shallowly into the elastic roller 10. As a result, the coating clearance D can be maintained constant regardless of the surface shape of the substrate 1.
[0056] Figure 18 is a schematic cross-sectional view showing the state of the die head 4 and the substrate 1 during coating. During coating, a bead 6 is formed between the tip 45 of the die head 4 and the substrate 1 by the discharged coating liquid. The substrate 1 is pressed into the elastic roller 10 by the action of the hydraulic pressure of the bead 6, so as to maintain a constant coating clearance D. Specifically, in areas where the surface of the substrate 1 is convex, the substrate 1 may be pressed deeply into the elastic roller 10. On the other hand, in areas where the surface of the substrate 1 is concave, the substrate 1 may be pressed shallowly into the elastic roller 10. As a result, the coating clearance D can be kept constant in the coating width direction (the direction perpendicular to the direction of travel of the die head 4), regardless of the surface shape of the substrate 1.
[0057] Thus, according to the coating apparatus and coating method of this embodiment, the coating liquid can be applied to a substrate with uneven thickness while maintaining a constant coating clearance in both the coating direction and the coating width direction, not only in a single-wafer system but also in a roll-to-roll system. As a result, according to the coating apparatus and coating method of this embodiment, a coating film with a uniform thickness can be formed.
[0058] This embodiment shows a case where the substrate 1 has uneven thickness. In contrast, the coating apparatus and coating method of this embodiment maintain a constant coating clearance even when the substrate 1 has warping, undulation, wrinkles, or lifting, because the bead 6 pushes the substrate 1 into the elastic body 10B. As a result, the coating apparatus and coating method of this embodiment can form a coating film of uniform thickness regardless of the warping, undulation, or uneven thickness of the substrate.
[0059] Furthermore, in this embodiment, a method of applying the coating liquid without pressing the substrate 1 onto the elastic roller 10 with the tip 45 of the die head 4 at the start of coating was shown. In contrast, in the coating apparatus and coating method of this embodiment, depending on the degree of thickness unevenness, warping, and undulation of the substrate, the coating liquid may be applied with the substrate 1 pressed onto the elastic roller 10 with the tip of the die head 4 at the start of coating.
[0060] Furthermore, this embodiment describes the case in which die head 4 is used. However, in this embodiment, the coating apparatus and coating method may also be used to apply the coating liquid using the die head 8 with a stepped tip (see Figure 10) shown in Embodiment 3, instead of die head 4.
[0061] [Embodiment 5] The coating apparatus and coating method of this embodiment (Embodiment 5) are provided with a die head 8 with a stepped tip (see Figure 10) as shown in Embodiment 3, in addition to the die head 4 (see Figure 7) of the coating apparatus 110 described above in relation to Embodiment 2.
[0062] Since this embodiment has the same apparatus configuration and coating method as Embodiment 2, except for the die head, a detailed explanation of the specific apparatus configuration and coating method will be omitted.
[0063] In this embodiment, since the contact surface 81a is separated from the substrate 1 during coating, it is preferable that the size of the step H at the tip of the die head 8 be about the same as or slightly smaller than the thickness of the coating film to be formed on the substrate 1. Specifically, the size of the step H is preferably 0.6 to 1 times the thickness of the coating film. Furthermore, from the viewpoint of forming a coating film with a uniform thickness in the coating width direction, it is preferable that the size of the step H be uniform in the width direction of the die head 8 with a step at the tip.
[0064] (1) A coating apparatus for applying a coating liquid to a substrate, comprising: a support; an elastic body supported by the support and in contact with the substrate; a die head having a tip portion with a discharge port formed therein for discharging the coating liquid, for discharging the coating liquid to the substrate supported by the support; and a moving mechanism for moving the die head along the surface of the substrate relative to the substrate.
[0065] With this configuration, the coating apparatus can press the substrate into the elastic body using the hydraulic pressure from the coating liquid between the tip of the die head and the substrate. This can generate a reaction force from the elastic body that pushes the substrate toward the tip of the die head. Due to this reaction force, the surface of the substrate comes into contact with the tip of the die head, either directly or via the coating liquid, and conforms to the tip. As a result, the coating clearance between the tip of the die head and the substrate can be kept constant. This allows the coating apparatus to form a uniform coating film with minimal coating defects or poor coating areas, even on substrates with warping, undulation, or uneven thickness.
[0066] (2) The coating apparatus according to (1), further comprising a pressing mechanism for pressing the tip of the die head against the substrate.
[0067] With this configuration, the coating apparatus can press the tip of the die head against the substrate using a pressing mechanism. As a result, even if the substrate has significant warping, undulation, or uneven thickness, the coating apparatus can easily and reliably press the substrate into an elastic body. This makes it easier to obtain a coating film that is less prone to coating defects and poorly coated areas, and maintains a uniform film thickness.
[0068] (3) The tip portion has a contact portion having a contact surface that is pressed against the substrate, and a non-contact portion having a non-contact surface that does not come into contact with the substrate when the contact surface is pressed against the substrate, and the discharge port is formed in the non-contact portion, the coating apparatus as described in (2).
[0069] With this configuration, even if the substrate has significant warping, undulation, or uneven thickness, the coating device can reliably press the substrate into the elastic body through the contact points. Furthermore, because the discharge port is formed in the non-contact area, the discharge port is less likely to be blocked by the pressed substrate, making it easier to stably apply the desired volume of coating liquid. In addition, the distance between the substrate surface and the non-contact area is easily maintained in the coating device. As a result, the resulting coating film is less prone to coating defects and poorly coated areas, and the film thickness is easily maintained to be uniform.
[0070] (4) The coating apparatus according to any one of (1) to (3), wherein the elastic body is a sponge, cushion, rubber, urethane, porous body, coil spring or elastomer.
[0071] With this configuration, the elastic body can easily deform when an external force is applied and easily return to its original shape when the external force is removed. Therefore, the elastic body can easily deform to conform to various shapes of substrates. As a result, the resulting coating film is less prone to coating defects and poorly coated areas, and the film thickness is easily maintained to be uniform.
[0072] (5) The coating apparatus according to any one of (1) to (4), wherein the support is a roller.
[0073] With this configuration, the coating apparatus can easily form a coating film while transporting the substrate, even if the substrate is long.
[0074] (6) The coating apparatus according to (5), wherein the elastic body covers the circumferential surface of the roller.
[0075] With this configuration, the coating apparatus can easily form a coating film while transporting the substrate, even if the substrate is long. Furthermore, the elastic body can easily deform when an external force is applied and can easily return to its original shape when the external force is removed. Therefore, the elastic body can easily deform to conform to substrates of various shapes, and as a result, the resulting coating film is less prone to coating defects and poorly coated areas, and the film thickness is easily maintained to be uniform.
[0076] (7) A coating method for applying the coating liquid to a substrate supported while in contact with the elastic body, using a coating apparatus described in any of (1) to (6), wherein the coating liquid is discharged from the discharge port of the tip to the substrate, the substrate is pushed into the elastic body by the hydraulic pressure of the coating liquid applied between the tip and the substrate, and the coating liquid is applied to the substrate by moving the die head relative to the substrate without the tip contacting the substrate.
[0077] With this configuration, the coating method allows the substrate to be pressed into the elastic body by the hydraulic pressure of the coating liquid between the tip of the die head and the substrate. This can generate a reaction force from the elastic body that pushes the substrate toward the tip of the die head. Due to this reaction force, the surface of the substrate comes into contact with the tip of the die head, either directly or via the coating liquid, and conforms to the tip. As a result, the coating clearance between the tip of the die head and the substrate can be kept constant. This makes the coating method less prone to coating defects and poorly coated areas, even on substrates with warping, undulation, or uneven thickness, and can form a coating film with a uniform thickness.
[0078] (8) A coating method for applying the coating liquid to a substrate using a coating apparatus described in any of (1) to (6), wherein the coating apparatus is equipped with a pressing mechanism for pressing the tip of the die head against the substrate, and at the start of coating, the pressing mechanism presses the tip of the die head against the substrate to push the substrate into the elastic body, and then the coating liquid is discharged from the discharge port of the tip onto the substrate, and the liquid pressure from the coating liquid applied between the tip and the substrate pushes the substrate into the elastic body, and the coating liquid is applied to the substrate by moving the die head relative to the substrate without the tip contacting the substrate.
[0079] With this configuration, the coating method allows the tip of the die head to be pressed against the substrate at the start of coating by the pressing mechanism. As a result, even if the substrate has significant warping, undulation, or uneven thickness, the coating method can reliably press the substrate into the elastic material. This makes it easier to obtain a coating film that is less prone to coating defects and poorly coated areas, and maintains a uniform film thickness.
[0080] (9) A coating method for applying the coating liquid to a substrate using a coating apparatus described in any of (1) to (6), wherein the tip portion has a contact portion having a contact surface that is pressed against the substrate, and a non-contact portion having a non-contact surface that does not come into contact with the substrate when the contact surface is pressed against the substrate, the discharge port is formed in the non-contact portion, the coating liquid is discharged from the discharge port of the tip portion onto the substrate while the substrate is pressed against the elastic body by the contact portion, and the coating liquid is applied to the substrate by moving the die head relative to the substrate such that the position of the contact portion is downstream in the direction of movement from the position of the non-contact portion, while accumulating the coating liquid between the non-contact portion and the substrate.
[0081] With this configuration, even if the substrate has significant warping, undulation, or uneven thickness, the coating method makes it easy to reliably press the substrate into the elastic body through the contact area. Furthermore, because the discharge port is formed in the non-contact area, the discharge port is less likely to be blocked by the pressed substrate, making it easy to stably apply the desired volume of coating liquid. In addition, the coating method makes it easy to maintain a constant distance between the substrate surface and the non-contact area. As a result, the resulting coating film is less prone to coating defects and poorly coated areas, and the film thickness is easily maintained to be uniform.
[0082] The present invention will be described more specifically below with reference to examples. The present invention is not limited in any way to these examples. Various modifications are possible without departing from the object and effect of the present invention.
[0083] [Example 1] The coating liquid was applied using the coating apparatus 120 shown in Figures 10 to 13. The step H at the tip 80 of the die head 8 with a stepped tip was set to 200 μm, taking into consideration the thickness of the coating film to be formed. The coating liquid used was a resin with a viscosity of 6 Pa·s (a mixture of Unilube® 75DE-15 and 75DE-2620 manufactured by Nippon Oil & Fats Co., Ltd., in a 1:1 ratio). The substrate 1 was a plate-shaped substrate (carbon fiber substrate) with a thickness of 2 mm and a curvature of about 0.5 mm. The elastic body 2 was an ethylene rubber sponge with a thickness of 10 mm and an Asker hardness of C8. The amount of indentation when the substrate 1 was pressed into the elastic body 2 by the tip 80 of the die head 8 with a stepped tip was set to 1 mm. The coating speed was 5 mm / s, and the amount of resin discharged was adjusted so that the coating film thickness before drying was 200 μm. During coating under these conditions, the substrate 1 and the tip 80 of the die head 8 with a stepped tip remained in contact and did not separate. When coating was performed under the above coating conditions, there were no coating defects such as uneven coating, and a uniform coating film was formed.
[0084] [Comparative Example 1] The same coating apparatus 120, coating liquid, and substrate 1 as in Example 1 were used, except that the elastic body 2 was removed. The coating speed was 5 mm / s, and the resin discharge amount was adjusted so that the coating film thickness before drying was 200 μm. The coating clearance between the tip 80 of the die head with a stepped tip 8 and the substrate 1 was set to 0.2 mm from the reference surface, using the convex part of the substrate 1 as the reference surface because the substrate 1 was warped. When coating was performed under the above conditions, the coating clearance became large in the concave parts of the substrate 1, making it impossible to hold the bead 6 (see Figure 13), resulting in coating gaps.
[0085] [Example 2] The coating liquid was applied using the coating apparatus 110 shown in Figures 7-9. However, a die head with a stepped tip 8 (see Figure 10) was used. The step H of the tip portion 80 was set to 25 μm from the thickness of the coating film to be formed. A resin with a viscosity of 230 Pa·s was used as the coating liquid. Material 1 was a 30 μm thick fibrous substrate with irregularities of about 10 μm. Elastic body 2 was a 2 mm thick silicone sponge with an Asker hardness of C15. The amount of indentation when the substrate was pressed into the elastic body by the die tip was set to 0.2 mm. The coating speed was 20 mm / s, and the resin discharge amount was adjusted so that the coating film thickness before drying was 25 μm. During coating under these conditions, the substrate and the die tip were separated. When coating was performed under the above coating conditions, a uniform coating film was formed without any coating defects such as missed spots.
[0086] The coating apparatus and coating method of the present invention can be widely applied to various applications such as functional films, paper products, fabric products, fiber-reinforced plastics, membrane products, batteries, electrical appliance components, and semiconductor components.
[0087] 1 Substrate 2 Elastic body 3 Support base 31 Rail section 4 Die head 41 Coating liquid inlet 42 Manifold 43 Slit-shaped flow path 44 Discharge port 45 Tip section 5 Moving mechanism 51 Leg section 52 Connecting section 53 Holding section 6 Bead 7 Pressing mechanism 8 Die head with stepped tip 80 Tip section 81 Contact section 81a Contact surface 82 Non-contact section 82a Non-contact surface 83 Discharge port 9 Conveyor roller 10 Elastic roller 10A Roller body section 10B Elastic body 100, 110, 120, 130 Coating device A Direction of movement of die head B Direction of conveying substrate D Coating clearance H Step
Claims
1. A coating apparatus for applying a coating liquid to a substrate, comprising: a support; an elastic body supported by the support and in contact with the substrate; a die head having a tip portion with a discharge port formed therein for discharging the coating liquid, for discharging the coating liquid to the substrate supported by the support; and a moving mechanism for moving the die head along the surface of the substrate relative to the substrate.
2. The coating apparatus according to claim 1, further comprising a pressing mechanism for pressing the tip of the die head against the substrate.
3. The tip portion has a contact portion having a contact surface that is pressed against the substrate, and a non-contact portion having a non-contact surface that does not come into contact with the substrate when the contact surface is pressed against the substrate, and the discharge port is formed in the non-contact portion, the coating apparatus according to claim 2.
4. The coating apparatus according to any one of claims 1 to 3, wherein the elastic body is a sponge, cushion, rubber, urethane, porous body, coil spring, or elastomer.
5. The coating apparatus according to any one of claims 1 to 4, wherein the support is a roller.
6. The coating apparatus according to claim 5, wherein the elastic body covers the circumferential surface of the roller.
7. A coating method for applying the coating liquid to a substrate supported while in contact with the elastic body, using the coating apparatus according to claim 1 or 2, wherein the coating liquid is discharged from the discharge port of the tip portion toward the substrate, the substrate is pushed toward the elastic body by the hydraulic pressure of the coating liquid applied between the tip portion and the substrate, and the coating liquid is applied to the substrate by moving the die head relative to the substrate without the tip portion coming into contact with the substrate.
8. A coating method for applying the coating liquid to a substrate supported while in contact with the elastic body, using the coating apparatus described in claim 2, wherein at the start of coating, the tip of the die head is pressed against the substrate by the pressing mechanism to push the substrate into the elastic body, and then the coating liquid is discharged from the discharge port of the tip onto the substrate, and the substrate is pushed into the elastic body by the hydraulic pressure of the coating liquid applied between the tip and the substrate, and the coating liquid is applied to the substrate by moving the die head relative to the substrate without the tip contacting the substrate.
9. A coating method for applying the coating liquid to a substrate supported while in contact with the elastic body, using the coating apparatus described in claim 3, wherein the coating liquid is discharged from the discharge port at the tip of the contact portion to the substrate while the substrate is pressed into the elastic body by the contact portion, and the coating liquid is applied to the substrate by moving the die head relative to the substrate such that the position of the contact portion is downstream in the direction of movement from the position of the non-contact portion, while accumulating the coating liquid between the non-contact portion and the substrate.