Slot-type spray nozzle, coating apparatus, and method for manufacturing coated member.

Abstract

A slot-type spray nozzle according to the present invention is provided with: a plurality of application liquid discharge ports arranged in one direction; a pair of air discharge ports that are disposed so as to sandwich the application liquid discharge ports, are open intermittently or continuously in the width direction near the application liquid discharge ports, and are formed such that air discharged from the discharge ports obliquely intersects with the discharge direction of the application liquid; and a pair of liquid holding surfaces that extend from edges forming widthwise opposite ends of the application liquid discharge ports along the discharge direction of the application liquid and that face each other with the application liquid discharge ports therebetween. When the length of the liquid holding surfaces in the discharge direction of the application liquid is denoted by H1 (μm), the angle (acute angle) formed between the discharge direction of air discharged from each of the air discharge ports and the discharge direction of the application liquid is denoted by θ (degrees), and the spacing between the application liquid discharge ports and each of the air discharge ports is denoted by L2 (μm), H1 satisfies being at least 30 μm and within a specific range.

Description

Technical Field

[0001] The present invention relates to a slot-type spray nozzle, a coating apparatus using the slot-type spray nozzle, and a method for manufacturing a member with a coating film using the coating apparatus.

Background Art

[0002] Conventionally, as an apparatus for applying a coating liquid to a substrate to be coated (hereinafter also simply referred to as a "substrate"), a spray coating apparatus that atomizes the coating liquid into droplets with a spray nozzle (hereinafter also simply referred to as a "nozzle") and then sprays it is known.

[0003] In this spray coating apparatus, from the viewpoints of the productivity and functionality of the substrate, it is often required to form a coating film thinly and with a uniform thickness on substantially the entire surface of a wide-width substrate.

[0004] As a coating means in such a case, for example, in Patent Document 1, squeezing air is discharged simultaneously with the coating liquid, and the coating liquid is atomized and sprayed by the strong impact force (collision force on the coating liquid) of the discharged air, so that a two-fluid type single-hole spray nozzle capable of forming a thin film is arranged in a plurality at equal intervals in the width direction of the substrate, and while spraying the coating liquid simultaneously so that the coating liquids sprayed from each nozzle overlap, the substrate is conveyed, and a spray coating apparatus for forming a thin coating film on a wide-width substrate is disclosed. However, in this spray coating apparatus, since each nozzle is an independent component, variation in the spraying state is likely to occur due to individual differences in the nozzles, that is, variation in the shape for each nozzle. Further, since the discharged air and the coating liquid droplets ejected from each nozzle fly while expanding in the width direction in a form such as a fan shape or a conical shape, interference occurs at the locations where the coating between the nozzles overlaps, and coating streaks are likely to occur, and it is difficult to form a uniform coating film.

[0005] To address the challenges of single-hole nozzles, Patent Document 2 discloses a slot-type spray nozzle that can apply a wide, thin, and uniform coating film. This nozzle has multiple coating liquid discharge ports in the coating width direction of the substrate, and a pair of air discharge ports that open continuously or intermittently across the width direction near the coating liquid discharge ports, flanking the coating liquid discharge ports. This spray nozzle generates fine coating droplets by instantaneously repeating the action of discharging the coating liquid to create a coating liquid reservoir exposed at the tip of the coating liquid discharge port, and then applying the force of discharged air to this coating liquid reservoir to detach it from the spray nozzle. Furthermore, because this spray nozzle is a single nozzle spanning the coating width, variations in the shape of each coating liquid discharge port are suppressed compared to a single-hole nozzle, allowing for highly uniform spraying of the coating liquid in the coating width direction. In addition, because it discharges a single, substantially continuous strip of air across the width direction of the substrate, the discharged air and coating droplets are sprayed approximately perpendicular to the width direction, reducing interference between the coating liquid discharge ports and enabling the formation of an extremely uniform, thin coating film on the substrate. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2013-111512 [Patent Document 2] Japanese Patent Publication No. 2006-026576 [Overview of the Initiative] [Problems that the invention aims to solve]

[0007] However, even with the slot-type spray nozzle disclosed in Patent Document 2, the straightness of the coated droplets may be disrupted after spraying, resulting in uneven coating. This is mainly because the airflow surrounding the spray nozzle is excited by the entrainment effect of the viscous fluid jet, and the interference of the entrained surrounding air affects the flight of the coated droplets. In particular, slot-type spray nozzles that discharge a substantially continuous strip of air tend to have a larger discharge airflow rate than a configuration with multiple two-fluid single-hole nozzles arranged in a row, and the larger the discharge airflow rate, the more it draws in surrounding air outside the nozzle, making the discharge airflow more prone to turbulence.

[0008] On the other hand, reducing the influence of ambient air can be achieved by decreasing the discharge air flow rate. However, when the discharge air flow rate is reduced, sufficient force cannot be applied to the coating liquid reservoir generated at the tip of the coating liquid discharge port. As a result, the coating liquid reservoir cannot be detached from the nozzle until it has grown to a certain size, which prevents the formation of fine coating droplets and thus prevents the formation of a thin coating film.

[0009] The present invention has been made in view of the above problems, and provides a spray nozzle that can form fine coating droplets even when the discharge air flow rate is reduced, and can uniformly form a thin coating film on a wide substrate. Furthermore, the present invention provides a spray coating apparatus using the spray nozzle and a method for manufacturing a coated member using the spray coating apparatus. [Means for solving the problem]

[0010] To solve the above problems, the present invention provides a slot-type spray nozzle comprising: a plurality of coating liquid discharge ports arranged in one direction; and a pair of discharge ports, with the one direction being the width direction, that open continuously or intermittently in the width direction near the coating liquid discharge ports and are arranged to sandwich the coating liquid discharge ports, wherein the air discharged from these discharge ports is formed to intersect the direction of coating liquid discharge at an oblique angle; The liquid-holding surfaces extend from the edges forming both ends in the width direction of the coating liquid discharge port in the direction of the coating liquid discharge, and are a pair of surfaces that face each other across the coating liquid discharge port. Let H1 (μm) be the length of the liquid-holding surface in the direction of discharge of the coating liquid, θ (degrees) be the angle (acute angle) between the direction of discharge of the air discharged from the air outlet and the direction of discharge of the coating liquid, and L2 (μm) be the distance between the coating liquid outlet and the air outlet. The following equation (1) is satisfied: H1 ≥ 30 μm. (L2 / tanθ)-100≦H1≦L2 / tanθ (1)

[0011] The slot spray nozzle of the present invention is preferably in the following form. (1) The coating liquid discharge port is formed from a comb-shaped shim and a pair of nozzle blocks that sandwich the comb-shaped shim, The comb-shaped shim described above protrudes from the tip of the nozzle block in the direction of discharge of the coating liquid. The liquid-holding surface is a portion of the comb-shaped shim that protrudes more than the nozzle block. (2) The portion of the comb-shaped shim that protrudes from the nozzle block, and the surface of the comb-shaped shim that can be observed from the thickness direction of the comb-shaped shim, has liquid-repellent properties against water. (3) The liquid-holding surface is approximately perpendicular to the width direction. (4) The radius of curvature of the ridge at the tip of the liquid-holding surface is 30 μm or less. (5) The above L2 is 100 μm or less.

[0012] The coating apparatus of the present invention comprises a slot-type spray nozzle, a supply means for supplying coating liquid and air to the slot-type spray nozzle, a support means for supporting a member to be coated, and a moving means for moving the member to be coated, which is supported by the support means, relative to the slot-type spray nozzle.

[0013] The manufacturing method of the member with a coating film of the present invention uses the coating apparatus of the present invention, discharges a coating liquid from the coating liquid discharge port while discharging air from the air discharge port, and sprays the coating liquid onto a member to be coated supported by the supporting means to manufacture a member on which a coating film is formed.

[0014] In the manufacturing method of the member with a coating film of the present invention, it is preferable that the air flow rate discharged from the air discharge port is 900 NL / min or more and 1500 NL / min or less per 1 m in width.

[0015] <P In the present application, the "width direction" means the direction in which a plurality of coating liquid discharge ports are arranged.

Effect of the Invention

[0016] By using the slot type spray nozzle of the present invention, a thin, wide and uniform coating film can be formed on a substrate.

Brief Description of the Drawings

[0017] [Figure 1] FIG. 1 is a perspective view showing a schematic configuration of the spray nozzle of the present invention. [Figure 2] FIG. 2 is a bottom view of the spray nozzle of the present invention as viewed from the coating liquid discharge port side. [Figure 3A] FIG. 3A is a diagram for explaining the flying state of coating liquid droplets during the coating with the spray nozzle of the present invention, and is a cross-sectional view as viewed from the width direction. [Figure 3B] FIG. 3B is a diagram for explaining the flying state of coating liquid droplets during the coating with the spray nozzle of the present invention, and is a cross-sectional view of the tip of one coating liquid discharge port as viewed from the conveyance direction of the substrate. [Figure 4A] FIG. 4A is a diagram for explaining the generation of coating liquid droplets during the coating with the spray nozzle of the present invention, and is a cross-sectional view of the tip of the spray nozzle as viewed from the width direction. [Figure 4B] FIG. 4B is a diagram for explaining the generation of coating liquid droplets during the coating with the spray nozzle of the present invention, and is a diagram obtained by erasing the coating liquid from the state shown in FIG. 4A. [Figure 5] FIG. 5 is a diagram for explaining the generation of coating droplets during spray nozzle coating, and is a cross-sectional view of the tip of a conventional spray nozzle without a liquid holding surface as viewed in the width direction. [Figure 6A] FIG. 6A is a diagram for explaining a preferred embodiment of the spray nozzle of the present invention, and is a cross-sectional view as viewed in the width direction. [Figure 6B] FIG. 6B is a diagram for explaining a preferred embodiment of the spray nozzle of the present invention, and is a view of the tip of one coating liquid discharge port as viewed in the conveyance direction of the substrate. [Figure 7] FIG. 7 is a cross-sectional view as viewed in the width direction for explaining the characteristic dimensions of the spray nozzle shown in FIGS. 6A and 6B. [Figure 8] FIG. 8 is an exploded perspective view for explaining the configuration of the spray nozzle shown in FIGS. 6A and 6B. [Figure 9] FIG. 9 is a side view showing a schematic configuration of a coating apparatus using the spray nozzle of the present invention.

Embodiments for Carrying Out the Invention

[0018] As a result of intensive studies on the above problems, the present inventors have focused on the fact that the coating liquid droplets are refined by separating them from the nozzle in a state where the coating liquid pool generated at the tip of the spray nozzle is small. More specifically, by making the position where the coating liquid pool is separated coincide with the position where the impact force of the discharge air is obtained, and by reducing the contact area between the coating liquid pool and the nozzle surface, the coating liquid droplets are refined. Thus, while maintaining a state where a thin film can be formed, by reducing the discharge air flow rate and reducing the deterioration of the straightness during the flight of the coating liquid droplets, the present inventors have found that the uniformity of the coating film can be improved, and have reached the present invention.

[0019] In addition, as the gas components of the air and outside air used in the present invention, there is no particular limitation as long as it is a gas suitable for coating, and air, nitrogen gas, etc. can be used. Also, there is no particular limitation on the atmospheric pressure of the outside air, and it can be an atmospheric pressure environment, a reduced pressure environment, etc.

[0020] Furthermore, there are no particular restrictions on the coating liquid used for spray coating, and examples include solutions of inorganic or organic substances, or slurries in which inorganic or organic substances are dispersed in a binder and a solvent. The viscosity of the coating liquid needs to be low enough that the coating liquid can be atomized by the force of the discharged air, and is generally preferably 500 mPa·s or less.

[0021] Embodiments of the present invention will be described in detail below with reference to the drawings. The following description is provided to facilitate understanding of the present invention and does not limit it in any way. The scope of the present invention is not limited to the following embodiments and includes all modifications within the scope of equivalence to the configurations described in the claims.

[0022] Figure 1 is a perspective view showing the schematic configuration of the spray nozzle of the present invention. Figure 1 shows a part of the spray nozzle 10, and the hatching in the figure indicates a cross-section of the spray nozzle 10. The spray nozzle 10 has a longitudinal direction perpendicular to the transport direction D of the long substrate 40, that is, in the width direction of the substrate 40, and is positioned at a certain distance from the substrate 40 so as to face the coating surface of the substrate 40. The coating liquid is supplied from a coating liquid supply port 16 located in the center of the width direction of the spray nozzle 10, widened in the width direction by a coating liquid manifold 18, and discharged from a coating liquid discharge port 31. The discharged air is supplied from air supply ports 15a and 15b located in the center of the width direction of the front and back of the spray nozzle 10, respectively, widened in the width direction by air manifolds 17a and 17b, and discharged from air discharge ports 33a and 33b, and the coating liquid discharged from the coating liquid discharge port 31 is dropletized by the force of the air. The droplets of the coating liquid are carried by the flow of discharged air and adhere to the substrate 40, thereby forming a coating film 41. There are no particular restrictions on the material of the components that make up the spray nozzle 10, but from the viewpoint of processing accuracy, durability, corrosion resistance, etc., it is preferable that all components be made of metal, especially stainless steel.

[0023] Figure 2 is a bottom view of the spray nozzle of the present invention as seen from the coating liquid discharge port side. In the bottom view of the spray nozzle 10 shown in Figure 2, the coating liquid discharge port 31 has a rectangular opening end, and multiple coating liquid discharge ports 31 are arranged at equal intervals in the width direction (left-right direction in Figure 2), forming the overall coating liquid discharge width W1. The optimal width W2 of each coating liquid discharge port 31 varies depending on the viscosity of the coating liquid used and the flow rate of the coating liquid to be discharged, but it is preferable to have a width of 100 μm or more from the viewpoint of reducing shape variations between discharge ports, and it is preferable to have a width of 400 μm or less in order to distribute a uniform amount of coating liquid from the coating liquid manifold 18 to each coating liquid discharge port 31. Furthermore, the arrangement pitch P of the coating liquid discharge ports 31 is preferably 10 mm or less from the viewpoint of uniformity in the width direction of the coating film.

[0024] Next, near the coating liquid discharge port 31, a pair of slit-shaped air discharge ports 33a and 33b with an air discharge width W3 are arranged so as to sandwich the coating liquid discharge port 31. In this case, the air discharge width W3 is longer than the coating liquid discharge width W1 in order to uniformly atomize all the coating liquid discharged from each coating liquid discharge port 31 with the force of the air. Note that the air discharge ports 33a and 33b may open as a single continuous slit in the width direction as shown in Figure 2, or they may open intermittently in a one-to-one correspondence with the coating liquid discharge port 31. If they open intermittently, they may be circular, elliptical, etc. If they open intermittently, it is preferable to make the opening length in the width direction greater than W2.

[0025] Figures 3A and 3B illustrate the flight state of the coating droplets during spray nozzle application according to the present invention. Figure 3A is a cross-sectional view taken from the width direction (hereinafter referred to as the width direction cross-sectional view). Figure 3B is a cross-sectional view of the tip of one coating liquid discharge port taken from the substrate transport direction.

[0026] In this spray nozzle 10, the coating liquid F is discharged from the coating liquid discharge port 31 shown in Figure 3A, and air G is discharged from a pair of air discharge ports 33a and 33b positioned on either side of the coating liquid discharge port 31. As shown in Figure 3B, near the tip of the coating liquid discharge port 31, there are liquid-holding surface forming members 34L and 34R, which have liquid-holding surfaces 35L and 35R that extend in the direction of coating liquid discharge from approximately the entire length of the sides forming both ends of the coating liquid discharge port 31 in the width direction. The discharged coating liquid F is held in a state of cross-linking between the pair of liquid-holding surfaces 35L and 35R of the liquid-holding surface forming members 34L and 34R. Furthermore, a coating liquid reservoir 37 is formed near the tip portions 36L and 36R of the liquid-holding surfaces 35L and 35R, which are the very front ends of the nozzle. When an air G (see Figure 3A) is applied to the coating liquid reservoir 37, the tip portions 36L and 36R become the liquid release points, separating the coating liquid and forming coating droplets 42 of a size corresponding to the size of the coating liquid reservoir 37. The instantaneous repetition of the formation and separation of the coating liquid reservoir 37 generates countless coating droplets 42 that fly toward the substrate 40 along with the air G, forming a coating film 41. In the case of a spray nozzle without liquid-holding surfaces 35L and 35R, the liquid release point of the coating liquid reservoir is the tip of the coating liquid discharge port 31, so the coating liquid reservoir 37 is in contact with the four inner surfaces that form the width and thickness directions of the rectangular coating liquid discharge port. On the other hand, in the spray nozzle 10 of the present invention, the coating liquid reservoir 37 is in contact with only two liquid-holding surfaces 35L and 35R, resulting in a small contact area and making it easier to separate the coating liquid reservoir. Therefore, even with a small air force, the droplets can be atomized. Furthermore, if the discharge direction length H1 of the liquid-holding surfaces 35L and 35R is small, and the tips of the coating liquid discharge port 31 and the liquid-holding surfaces 35L and 35R are in close proximity, the liquid reservoir 37 will substantially come into contact with the four inner surfaces that form the width and thickness directions of the rectangular coating liquid discharge port 31, and the effects of the present invention cannot be obtained. Therefore, H1 must be 30 μm or more. In addition, in order to stably crosslink and retain the discharged coating liquid, it is preferable that H1 be 400 μm or less.

[0027] The supply conditions for the air G discharged from the air outlets 33a and 33b cannot be defined in general terms, as they depend on the desired type of coating liquid, coating film thickness, etc. However, from the viewpoint of minimizing the air flow rate used while maintaining the impact force for atomizing droplets, and minimizing turbulence in the discharged air flow, the pressure measured at the air manifolds 17a and 17b is preferably in the range of 50 kPa to 200 kPa, and the air flow rate is preferably 900 NL / min to 1500 NL / min per 1 m of air discharge width.

[0028] Figures 4A, 4B, and 5 illustrate the generation of coating droplets during spray nozzle application. Figure 4A is a cross-sectional view in the width direction of the tip of the spray nozzle of the present invention. Figure 4B shows the state shown in Figure 4A with the coating liquid removed. Figure 5 is a cross-sectional view in the width direction of the tip of a conventional spray nozzle that does not have a liquid-holding surface.

[0029] As shown in Figure 4A, the coating droplet 42 is generated at the position X1 where the impact force of the discharged air G is obtained (hereinafter simply referred to as the "impact position"). This impact position X1 is the intersection of a pair of virtual extensions Va and Vb that are extended in the direction of air discharge from the edges of the air discharge ports 33a and 33b on the coating liquid discharge port 31 side. Furthermore, since the coating liquid reservoir 37 is generated in the space between the nozzle tip 36L (36R), which is the liquid release position, and the impact position, the coating liquid reservoir 37 can be reduced by bringing the nozzle tip 36L (36R) closer to the impact position X, thereby reducing this space and making the generated coating droplet 42 smaller. However, as shown in Figure 4B, if the liquid holding member 34L (34R) is brought close to the impact position X1 and intersects diagonally with the virtual extension lines Va and Vb at points X2a and X2b, the discharged air G may collide with the liquid holding member 34L (34R) and become turbulent, potentially reducing the coating accuracy. Here, the distance from the coating liquid discharge port to points X2a and X2b can be expressed as L2 / tanθ, where θ is the angle (acute angle) between the discharge direction of the air discharged from the air discharge port and the discharge direction of the coating liquid (here, for example, let θ be the angle between the virtual extension line Vb and the liquid holding surface of the liquid holding member 34L), and L2 (μm) is the distance between the coating liquid discharge port and the air discharge port. Hereafter, the angle θ may be referred to as the "air discharge angle θ". To prevent the above problem from occurring, the discharge direction length H1 (μm) of the liquid holding surface must satisfy the range of the following equation (1). (L2 / tanθ)-100≦H1≦L2 / tanθ (1)

[0030] In the case of a conventional spray nozzle that does not have a liquid-holding surface as shown in Figure 5, the liquid reservoir 37 is generated between the tip of the liquid discharge port 38 and the impact position, so the liquid reservoir 37 is larger than that of the spray nozzle of the present invention, and the generated liquid droplets 42 are also larger.

[0031] Here, an example of a preferred embodiment of the spray nozzle will be described with reference to Figures 6A and 6B. Figures 6A and 6B illustrate a preferred embodiment of the spray nozzle of the present invention. Figure 6A is a cross-sectional view in the width direction. Figure 6B is a view of the tip of one coating liquid discharge port as seen from the substrate transport direction.

[0032] As shown in Figure 6A, the liquid-holding surface 35L(35R) is preferably formed by creating a coating liquid discharge port 31 from a comb-shaped shim 12 and a pair of nozzle blocks 13a and 13b that sandwich the comb-shaped shim 12, with the comb-shaped shim 12 protruding in the direction of coating liquid discharge from the tips of the nozzle blocks 13a and 13b. By making the liquid-holding surface 35L(35R) a part of the comb-shaped shim 12, the area from the coating liquid discharge port 31 to the liquid-holding surface 35L(35R) becomes flush without any connection parts, thus stabilizing the discharge of the coating liquid. Furthermore, since each liquid-holding surface 35L(35R) corresponding to a plurality of coating liquid discharge ports 31 is composed of a single part, variations in shape can be suppressed, and high coating accuracy can be maintained.

[0033] The surface S (and similarly the back surface) of the comb-shaped shim 12 that protrudes from the nozzle block as shown in Figure 6B and can be observed from the thickness direction of the comb-shaped shim 12 is preferably liquid-repellent. By imparting liquid repellency to surface S, the wetting and spreading of the coating liquid crosslinked by the liquid-holding surfaces 35L and 35R onto surface S can be reduced, thereby creating a stable coating liquid reservoir. Note that liquid repellency means that the contact angle of surface S with pure water is 90° or more, and more preferably 120° or more. In this invention, it is preferable to use a metal material, particularly stainless steel, as the material used for the comb-shaped shim from the viewpoint of processing accuracy, durability, and corrosion resistance, so coatings such as fluororesin and water-repellent plating films can be used as methods for imparting liquid repellency. Furthermore, from the viewpoint of liquid-repellent durability, it is more preferable to modify the metal surface by micro-nano patterning or the like to impart liquid repellency.

[0034] It is desirable that the liquid-holding surfaces 35L and 35R are approximately perpendicular to the width direction. If the liquid-holding surfaces 35L and 35R do not widen towards the liquid discharge direction, the gap between the nozzle tip 36L and 36R will not widen, allowing for stable cross-linking and retention of the coating liquid. Also, if the liquid-holding surfaces 35L and 35R do not narrow towards the liquid discharge direction, the coating liquid will not ride up onto surface S, resulting in stable formation of coating droplets. By having the liquid-holding surfaces 35L and 35R approximately perpendicular to the width direction, the coating liquid discharged from the coating liquid discharge port 31 can be stably cross-linked and retained. Furthermore, variations in the ejection direction of coating droplets when the coating pool is separated by the force of the discharged air can be reduced. Note that "approximately perpendicular" means that manufacturing errors are tolerated, and the angle between the normal to the liquid-holding surfaces 35L and 35R and the width direction is 5 degrees or less.

[0035] The radius of curvature of the ridges at the tips 36L and 36R of the liquid-holding surfaces 35L and 35R is preferably 30 μm or less. The smaller the radius of curvature, the more stable the release of the coated liquid from the reservoir is at the ridge, thereby reducing the variation in the ejection direction of the coated liquid droplets when the reservoir is separated by the discharged air.

[0036] Figure 7 is a cross-sectional view in the width direction illustrating the characteristic dimensions of the spray nozzle shown in Figures 6A and 6B. In Figure 7, the angle (for example, angle θ) between the coating liquid discharge port 31 and the air discharge ports 33a and 33b is preferably 15 degrees or more and 45 degrees or less. When the angle θ is 15 degrees or more, the air discharged from the air discharge ports 33a and 33b can impart sufficient force to the coating liquid to form droplets. When θ is 45 degrees or less, fewer coating liquid droplets fly in the direction of substrate travel, so fewer coating liquid droplets scatter without adhering to the substrate, and a decrease in the efficiency of using the coating liquid can be suppressed.

[0037] The optimal gap L1 between the coating liquid outlets 31 varies depending on the viscosity of the coating liquid used and the flow rate of the coating liquid being discharged. However, from the viewpoint of reducing variations in the shape of each outlet, a gap of 50 μm or more is preferred, and a gap of 200 μm or less is preferred in order to ensure a uniform amount of coating liquid is distributed from the coating liquid manifold to each coating liquid outlet.

[0038] The distance L2 between the coating liquid discharge port 31 and the air discharge ports 33a and 33b is preferably 100 μm or less. When the distance L2 is 100 μm or less, the distance from the air discharge port tips 33a and 33b to the impact position is short, so the impact force of the air applied to the coating liquid can be sufficiently large. In addition, the length H1 of the liquid holding surface 35L (35R) can be kept short, so the coating liquid can be stably crosslinked and held.

[0039] The distance between the air outlets 33a and 33b (e.g., the gap L3) is preferably 100 μm or less. When the gap L3 is 100 μm or less, the average flow velocity of the discharged air is sufficiently large, and the force of the air applied to the coating liquid is also sufficiently large, so that the coating droplets can be atomized. Furthermore, the amount of air required to atomize the coating droplets can also be reduced.

[0040] Figure 8 is an exploded perspective view illustrating the configuration of the spray nozzle shown in Figures 6A and 6B. In Figure 8, the spray nozzle 10 is composed of parts labeled 12, 13a, 13b, 14a, and 14b. Reference numerals 13a and 13b are inner blocks for forming the coating liquid manifold 18 and the coating liquid outlet 31. One of the inner blocks 13a has a coating liquid supply port 16 for receiving the coating liquid and a coating liquid manifold 18 for widening the coating liquid in the width direction. The coating liquid supply port 16 communicates from the outer surface of the inner block 13a to the coating liquid manifold 18. Next, reference numeral 12 is a comb-shaped shim sandwiched between the inner blocks 13a and 13b. When the inner blocks 13a and 13b are joined with the shim 12, a plurality of coating liquid outlets 31 are formed in the width direction by the gaps between the comb teeth of the shim 12. Furthermore, the height H3 of the shim 12 is greater than the height H4 of the inner blocks 13a and 13b. By making the height H3 greater than the height H4 by a length H1, the comb-shaped shim 12 protrudes by a length H1 in the direction of discharge of the coating liquid from the tip of the nozzle blocks 13a and 13b, thereby forming a liquid-holding surface. Reference numerals 14a and 14b are outer blocks, and when combined with the inner blocks 13a and 13b, they form air discharge ports for discharging air. In this case, the shape of the air discharge port is a single continuous slit in the width direction. Each of the outer blocks 14a and 14b has an air supply port 15a and 15b for receiving air, and an air manifold 17a and 17b on the mating surface side with the outer blocks 14a and 14b for expanding the air in the width direction. The air supply ports 15a and 15b are in communication from the outer surface of the outer blocks 14a and 14b to the air manifolds 17a and 17b, respectively.

[0041] Figure 9 is a side view showing a schematic configuration of a coating apparatus using a spray nozzle of the present invention. The spray coating apparatus 60 in Figure 9 consists of a coating means 80 having a spray nozzle 10, a supply means 70 that supplies coating liquid and air to the spray nozzle 10, and a feed roll 61 which is a moving means that moves the substrate 40 relative to the spray nozzle 10.

[0042] The coating means 80 consists of a spray nozzle 10, a backup roll 81 which is a substrate support means, a booth 82 which surrounds them, a waste liquid recovery tank 83, and a depressurization means 84. The backup roll 81 supports the substrate being transported at the coating portion of the spray nozzle. The booth 82 is a substantially sealed system except for the inlet opening 85 and outlet opening 86 through which the substrate 40 passes, preventing coating droplets discharged from the spray nozzle 10 from scattering outside the coating means 80. The lower opening 87 of the booth is in communication with the waste liquid recovery tank 83, and any excess coating liquid generated inside the booth falls along the slope 88 inside the booth and is collected in the waste liquid recovery tank 83 via the lower opening 87. The rear opening 89 of the booth is connected to the depressurization means 84 via an intake pipe 90. When the depressurization means 84 is driven to create a depressurized environment inside the booth, outside air flows into the booth through the inlet opening 85 and the outlet opening 86, thus preventing the coating liquid discharged from the spray nozzle 10 from scattering outside the booth.

[0043] The supply means 70 supplies the coating liquid to the spray nozzle 10 via the coating liquid piping 73 using the coating liquid tank 71 and the metering pump 72. It also supplies air, whose pressure has been regulated by the pressurized air source 74 and the pressure regulating valve 75, to the spray nozzle 10 via the air piping 76 and the branch pipe 77.

[0044] The feed roll 61, which is a means of movement, is connected to a drive means (not shown). By rotating the feed roll 61 with the drive means, the substrate 40 is conveyed in the conveying direction D at an arbitrary conveying speed.

[0045] This spray coating apparatus 60 can form a uniform coating film 41 on a conveyed substrate 40 and manufacture a coated member 43. Furthermore, the apparatus may also be equipped with a drying means to dry the coating film 41 on the coated member 43 conveyed from the coating apparatus 60. The drying method for the coating film is not particularly limited; methods such as blowing hot air or using a heat oven with a heater can be used.

[0046] The spray nozzle 10 of the present invention used in this spray coating apparatus 60 can generate fine coating droplets even with a small air flow rate that does not disrupt the straight-line movement of the flying coating droplets, thereby obtaining a member 43 with a thin, wide coating film that is highly uniform in the width direction.

[0047] Although Figure 9 shows an example of a spray coating apparatus 60 in which the coating means 80 is not moved and the substrate 40 is transported (moved) by a moving means, the coating apparatus of the present invention may also be configured in which the substrate 40 is not moved and the coating means 80 is moved by a moving means. [Examples]

[0048] Examples are described below, but the embodiments of the present invention are not limited to these examples.

[0049] Using the spray coating apparatus shown in Figure 9, spray conditions were prepared by changing the discharge direction length H1 (μm) of the liquid-holding surface, the shape of the liquid-holding surface, the distance L2 (μm) between the coating liquid outlet and the air outlet, and the air flow rate per 1 m of width (NL / min) as shown in Table 1, and these were used as comparative examples and examples. Note that "orthogonal" means that the liquid-holding surface is perpendicular to the width direction, and in the case of "narrowing at the end" and "widening at the end," the angle (dihedral angle) between a pair of opposing liquid-holding surfaces was set to 30°.

[0050] The spray nozzle has a coating liquid discharge width W1 of 1000 mm, a gap L1 between the coating liquid discharge ports of 100 μm, and an air discharge angle θ of 25°, with the air discharge port having a single slit shape in the width direction.

[0051] The coating solution used was a dispersion in which the resist pigment was dispersed in propylene glycol monomethyl ether acetate (PMA) to a solid content concentration of 14% by mass and a viscosity of 4.0 cp. The spray flow rate of the coating solution was 100 ml / min.

[0052] [Evaluation of average droplet diameter] Since the feasibility of forming a thin film of a coating by spray atomization cannot be uniformly determined due to varying spraying conditions such as substrate transport speed and coating liquid flow rate, the fineness of the average diameter of the generated droplets was used for comparative evaluation.

[0053] Under each condition shown in Table 1, the diameter of the coated droplets sprayed from the spray nozzle was measured using a laser diffraction particle size analyzer FLD-319A manufactured by Seika Digital Image Co., Ltd. The measurement was performed by irradiating a group of coated droplets located 120 mm away from the tip of the spray nozzle in the discharge direction with laser light perpendicular to both the width direction and the discharge direction of the spray nozzle. The measured average droplet diameter was evaluated according to the following evaluation rank. The Sauter mean particle size was used as the average droplet diameter.

[0054] [Average droplet diameter evaluation rank] ○: Average particle size of coated droplets is less than 30 μm ×: Average particle size of coated droplets is 30 μm or larger.

[0055] [Evaluation of coating film uniformity] Next, to evaluate the uniformity of the coating film, the coating solution was sprayed onto a PET film under each condition shown in Table 1 to form a coating film. The coating film thickness of the prepared coating film was measured at 10 mm intervals in the width direction, and the variation from the average film thickness was calculated to evaluate the uniformity of the coating film according to the evaluation rank shown below. The distance from the tip of the spray nozzle to the substrate was set to 120 mm. The substrate was a PET film with a substrate width of 1000 mm and a thickness of 100 μm, and was transported at a speed of 1 m / min.

[0056] [Evaluation rank for uniformity of coating film] ◎: No film thickness variations exceeding ±10% occurred. ○: Film thickness variation exceeding ±10% occurred. Film thickness variation exceeding 15% did not occur. ×: Film thickness variation exceeding ±15% occurred.

[0057] [Example 1] The evaluation was performed under the conditions of H1 being 40 μm, L2 being 50 μm, the liquid-holding surface shape being orthogonal, and the air discharge flow rate being 1200 NL / min per 1 m width. Both the average droplet diameter and the uniformity of the coating film thickness were good results. The setting conditions and evaluation results for Example 1 are shown in Table 1. [Table 1]

[0058] [Example 2] The conditions were the same as in Example 1, except that H1 was changed to 100 μm. Both the average droplet diameter and the uniformity of the coating film thickness were good. The setting conditions and evaluation results for Example 2 are shown in Table 1.

[0059] [Example 3] The conditions were the same as in Example 2, except that the air discharge flow rate was increased to 1600 NL / min per 1 m width. Compared to Example 2, turbulence in the discharged air occurred, but both the average droplet diameter and the uniformity of the coating film thickness were good. The setting conditions and evaluation results for Example 3 are shown in Table 1.

[0060] [Example 4] The conditions were the same as in Example 2, except that the shape of the liquid-holding surface was changed to a tapering shape. Although some of the coating liquid discharged from the multiple coating liquid discharge ports in the width direction rode onto the liquid-holding surface forming member, the average droplet diameter and coating film thickness uniformity were both good results. The setting conditions and evaluation results for Example 4 are shown in Table 1.

[0061] [Example 5] The conditions were the same as in Example 2, except that the shape of the liquid-holding surface was changed to a flared shape. Although some of the coating liquid discharged from the multiple coating liquid discharge ports in the width direction could not be held to the tip of the nozzle and formed into coating droplets, the average droplet diameter and coating film thickness uniformity were both good results. The setting conditions and evaluation results for Example 5 are shown in Table 1.

[0062] [Example 6] The evaluation was performed under the conditions of H1 being 200 μm, L2 being 100 μm, the liquid-holding surface shape being orthogonal, and the air discharge flow rate being 1200 NL / min per 1 m width. Both the average droplet diameter and the uniformity of the coating film thickness were good results. The setting conditions and evaluation results for Example 6 are shown in Table 1.

[0063] The conditions were the same as in Example 1, except that H1 was changed to 0 μm. The average diameter of the coated droplets was large, and because the average diameter was large, granular unevenness occurred in the coated film, resulting in low uniformity of the coated film. The setting conditions and evaluation results for Comparative Example 1 are shown in Table 1.

[0064] [Comparative Example 2] The conditions were the same as in Example 1, except that H1 was changed to 20 μm. Similar to Comparative Example 1, the average diameter of the coated droplets was large, and because the average diameter was large, granular unevenness occurred in the coated film, resulting in low uniformity of the coated film. The setting conditions and evaluation results for Comparative Example 2 are shown in Table 1.

[0065] [Comparative Example 3] The conditions were the same as in Example 1, except that H1 was changed to 150 μm. Because the discharged air collided with the liquid-holding surface forming member, the flow of the discharged air was turbulent, resulting in low uniformity of the coating film. The setting conditions and evaluation results for Comparative Example 3 are shown in Table 1.

[0066] [Comparative Example 4] The conditions were the same as in Example 6, except that H1 was changed to 100 μm. The result was a large average diameter of the coated droplets, and because of the large average diameter, granular unevenness occurred in the coated film, resulting in low uniformity of the coated film. The setting conditions and evaluation results for Comparative Example 4 are shown in Table 1.

[0067] [Comparative Example 5] The conditions were the same as in Example 6, except that H1 was changed to 300 μm. Because the discharged air collided with the liquid-holding surface forming member, the flow of the discharged air was disturbed, resulting in low uniformity of the coating film. The setting conditions and evaluation results for Comparative Example 5 are shown in Table 1.

[0068] The above examples confirmed that the coated droplets were miniaturized and the uniformity of the coated film was improved, thus confirming the effectiveness of the present invention. [Industrial applicability]

[0069] The present invention is effective as a slot-type spray nozzle, coating apparatus, and method for manufacturing a coated component, which can form fine coating droplets even when the discharge air flow rate is reduced, and can uniformly form a thin coating film on a wide substrate. [Explanation of Symbols]

[0070] 10 spray nozzles 12. Comb-shaped shims 13a, 13b Inner nozzle block 14a, 14b Outer nozzle block 15a, 15b Air supply ports 16 Coating liquid supply port 17a, 17b Air Manifold 18. Coating liquid manifold 31 Application liquid discharge port 33a, 33b Air discharge port 34 Liquid-holding surface forming member 35L, 35R liquid holding surface 36L, 36R Nozzle tip 37. Liquid reservoir 38 Tip of the coating liquid discharge port 40 Base material 41 Coating film 42 Application droplet 43 Substrate with coated film 60 Spray coating device 61 Feed Roll 70 Means of supply 71 Coating liquid tank 72 Metering pump 73. Coating liquid piping 74 Pressurized air source 75 Pressure regulating valve 76 Air Piping 77 Branch pipe 80 Coating means 81 Backup Role 82 booths 83. Drainage recovery tank 84 Depressurization means 85 Inlet opening 86 Exit opening 87 Lower opening 88 Booth Slope 89 Back opening 90 Intake pipe D Conveying direction F Coating solution G Discharge air H1 Discharge direction length of liquid holding surface H3 Combo-shaped shim height H4 Inner block height L1 Gap between coating liquid discharge port L2 Distance between the coating liquid outlet and the air outlet L3 Air outlet thickness P: Pitch of the coating liquid discharge port arrangement Surface of the comb-shaped shim that can be observed from the thickness direction. Va, Vb: Virtual extension of the discharged air. W1 Coating liquid discharge width W2 Coating liquid discharge port width W3 Air discharge width X1 Hitting position X2a, X2b are points where the discharged air collides with the liquid-holding member. θ Air discharge angle

Claims

1. Multiple coating liquid discharge ports arranged in one direction, With the aforementioned one direction as the width direction, a pair of discharge ports are opened continuously or intermittently in the width direction near the coating liquid discharge port and are arranged to sandwich the coating liquid discharge port, and the air discharged from the discharge ports is formed to intersect the direction of coating liquid discharge at an oblique angle, A slot-type spray nozzle equipped with, The liquid-holding surfaces extend from the edges forming both ends in the width direction of the coating liquid discharge port in the direction of coating liquid discharge, and are a pair of surfaces facing each other on either side of the coating liquid discharge port. Let H1 (μm) be the length of the liquid-holding surface in the direction of discharge of the coating liquid, θ (degrees) be the angle (acute angle) between the direction of discharge of the air discharged from the air outlet and the direction of discharge of the coating liquid, and L2 (μm) be the distance between the coating liquid outlet and the air outlet. H1 ≥ 30 μm, and satisfying the following formula (1), Slotted spray nozzle. (L2 / tanθ)-100≦H1≦L2 / tanθ ・・・（１）

2. The coating liquid discharge port is formed from a comb-shaped shim and a pair of nozzle blocks that sandwich the comb-shaped shim. The comb-shaped shim protrudes from the tip of the nozzle block in the direction of discharge of the coating liquid, The slot-type spray nozzle according to claim 1, wherein the liquid-holding surface is a part of the portion of the comb-shaped shim that protrudes more than the nozzle block.

3. The slot-type spray nozzle according to claim 2, wherein the portion of the comb-shaped shim that protrudes from the nozzle block has a surface observable from the thickness direction of the comb-shaped shim that is liquid-repellent to water.

4. The slot-type spray nozzle according to claim 1, wherein the liquid-holding surface is substantially perpendicular to the width direction.

5. The slot-type spray nozzle according to claim 1, wherein the radius of curvature of the ridge at the tip of the liquid-holding surface is 30 μm or less.

6. The slot-type spray nozzle according to claim 1, wherein L2 is 100 μm or less.

7. A slot-type spray nozzle according to any one of claims 1 to 6, A supply means for supplying coating liquid and air to the aforementioned slot-type spray nozzle, Support means for supporting the member to be coated, A moving means for moving the member to be coated, which is supported by the support means, relative to the slot-type spray nozzle, A coating apparatus equipped with a coating device.

8. A method for manufacturing a coated member, comprising using the coating apparatus described in claim 7, discharging air from the air discharge port while discharging a coating liquid from the coating liquid discharge port, and spraying the coating liquid onto a member to be coated supported by the support means, thereby manufacturing a member on which a coated film has been formed.

9. The method for manufacturing a coated member according to claim 8, wherein the air flow rate discharged from the air outlet is 900 NL / min or more and 1500 NL / min or less per meter of width.

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