Coating device, coating method, and coating film production method

Abstract

To provide a coating device which can prevent particulates from settling and accumulating on a bottom of a coating liquid pan over time, a coating method and a coating film production method.SOLUTION: A coating device, which coats coating liquid onto a sheet-like base material such as a film and so on via a coating roll, comprises: a coating liquid supply part which temporarily stores the coating liquid supplied from a plurality of pipelines in a liquid reservoir, and discharges the coating liquid overflowing from the liquid reservoir via a slit provided along a longer direction of the liquid reservoir; a coating liquid pan which is wholly u-shaped in a cross section perpendicular to a longer direction of the coating roll, and of which a bottom facing the coating roll has a shape curved downward; a coating liquid discharge part which discharges the coating liquid overflowing from the coating liquid pan on the other end side of the coating liquid pan; and a coating liquid pan angle adjustment part which can adjust an angle of an inclined plane from the bottom of the coating liquid pan to the coating liquid discharge part with respect to a horizontal plane in the cross section perpendicular to the longer direction of the coating roll.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a coating device for a coating fluid, a coating method, and a coating film production method. [Background technology]

[0002] Conventionally, in a coating device that applies a coating liquid to a sheet-like substrate via a coating roll such as a gravure roll, the coating liquid is generally discharged from a coating liquid supply unit located upstream of the coating liquid pan toward the center of the coating liquid pan and stored in the coating liquid pan, the coating roll is immersed in the liquid reservoir in the coating liquid pan, and the coating liquid is transferred to the substrate via the rotating coating roll to form a coating film. Usually, the coating liquid is supplied in excess, and the excess coating liquid that overflows from the coating liquid pan is collected and supplied again to the coating liquid pan.

[0003] For example, in Patent Document 1, a coating liquid supply section is provided that temporarily stores the coating liquid supplied from a plurality of pipes arranged along the longitudinal direction of the coating roll in a container, and supplies the coating liquid overflowing from the container to a coating liquid pan through an opening along the longitudinal direction.

[0004] Here, if the coating liquid contains granular matter that is prone to settling, and the granular matter settles and accumulates over time as the coating liquid accumulates in the coating liquid pan, problems such as a decrease in the concentration of the granular matter in the coating film transferred to the substrate can occur.

[0005] Therefore, measures have been taken such as sloping the coating liquid pan from the bottom to the coating liquid outlet (discharge port) to allow the coating liquid to flow smoothly from the reservoir in the coating liquid pan to the outlet and to prevent granular matter, etc. from settling and accumulating in the coating liquid pan. For example, in Patent Document 2, in order to prevent settling and accumulation of pigments that tend to settle and separate in the coating liquid, the shape of the bottom of the coating liquid pan is made to match the outer shape of the coating roll in order to further reduce stagnation of the flow of the coating liquid in the coating liquid pan.

[0006] Furthermore, for example, in Patent Document 3, in the space where the coating liquid is present between the coating roll and a coating liquid pan having an arc-shaped inner surface, the shortest distance between the coating liquid pan and the coating roll at the end on the coating liquid supply side and the shortest distance between the coating liquid pan and the coating roll at the end on the coating liquid discharge side are made different, thereby making the movement speed of the coating liquid different at these two ends and preventing the coating components from settling and / or agglomerating in the coating liquid pan. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Patent No. 5454044 [Patent Document 2] Patent No. 5315985 [Patent Document 3] Patent No. 6292750 Summary of the Invention [Problem to be solved by the invention]

[0008] If the concentration of granular matter, etc. in the liquid pool in the coating liquid pan is not uniform along the longitudinal direction of the coating roll, the concentration of granular matter, etc. in the coating film transferred to the substrate via the coating roll will be uneven along the longitudinal direction, which will ultimately result in uneven quality of the coated product. The coating devices of Patent Documents 1 to 3 described above do not provide sufficient measures to make the concentration of granular matter, etc. in the coating liquid pool in the coating liquid pan uniform along the longitudinal direction of the coating roll and to prevent the granular matter, etc. from settling and accumulating at the bottom of the coating liquid pan.

[0009] The present invention has been made in consideration of the above problems, and an object of the present invention is to provide a coating device, a coating method, and a coating film production method that solve the above problems. [Means for solving the problem]

[0010] In order to achieve the above object, a coating device according to an aspect of the present invention has the following configuration. In a coating device that applies a coating liquid to a sheet-like substrate such as a film through a coating roll, a coating liquid supply unit provided at one end side of the coating liquid pan, the coating liquid being supplied from a plurality of pipes arranged along the longitudinal direction of the coating roll, temporarily storing the coating liquid in a liquid reservoir, and discharging the coating liquid overflowing from the liquid reservoir through a slit provided along the longitudinal direction of the liquid reservoir; the coating liquid pan for storing the discharged coating liquid, the coating liquid pan being generally U-shaped in a cross section perpendicular to the longitudinal direction of the coating roll, and the bottom portion facing the coating roll having a shape curved downward; a coating liquid discharge section that is provided at a position lower than the coating liquid supply section at the other end side of the coating liquid pan that faces the one end side of the coating liquid pan via the coating roll, and that discharges the coating liquid that has overflowed from the coating liquid pan; and a coating fluid pan angle adjustment section that is capable of adjusting the angle of a slope extending from the bottom of the coating fluid pan to the coating fluid discharge section relative to a horizontal plane in a cross section perpendicular to the longitudinal direction of the coating roll. Effect of the Invention

[0011] In the coating device of the present invention configured in this manner, the coating liquid is supplied from the coating liquid supply section to the coating liquid pan at a uniform flow rate along the longitudinal direction of the coating roll, and further, when the coating liquid contains particulate matter or the like that is prone to settling, the concentration of the particulate matter or the like in the coating liquid in the coating liquid pan is made uniform along the longitudinal direction of the coating roll, and the particulate matter or the like can be effectively prevented from settling and accumulating at the bottom of the coating liquid pan over time.

[0012] Other objects, features and advantages of the present invention will become apparent from the following detailed description of the preferred embodiments of the present invention taken in conjunction with the accompanying drawings. [Brief description of the drawings]

[0013] [Figure 1]1 is a schematic cross-sectional view showing an overall configuration of a coating device according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a perspective view of a main part of the coating device shown in FIG. [Diagram 3] FIG. 2 is a plan view of a main part of the coating device shown in FIG. [Figure 4] FIG. 2 is a perspective view of a main part of the coating device shown in FIG. [Diagram 5] 2. (a) is a side cross-sectional view of the coating fluid supply unit taken along line II' in FIG. 2. (b) is a perspective view of the coating fluid supply unit. (c) is a perspective view showing a modified example of the coating fluid supply unit. [Figure 6] FIG. 3(a) is a side cross-sectional view of the coating fluid supply unit taken along line II' in FIG. 2, showing the inclined state, and FIG. 3(b) is a schematic perspective view of the coating fluid supply unit and a coating fluid supply unit tilting device. [Figure 7] 2(a) and 2(b) are side cross-sectional views of the main part of a typical example of a coating fluid pan taken along line II' in FIG. [Figure 8] 3(a), (b), and (c) are side cross-sectional views taken along line II' in FIG. 2, showing the configuration of main parts such as a coating liquid pan and a coating liquid pan angle adjustment unit. [Figure 9] 2. FIG. 5 is a side cross-sectional view taken along line II' in FIG. 2, showing a configuration of a main part of a modified example of a coating liquid pan angle adjustment unit. [Figure 10] 1. FIG. 4 is a plan view of a main portion of the coating device when a modified example of the coating liquid pan angle adjustment unit is applied to the coating device shown in FIG. [Figure 11] FIG. 2 is a schematic diagram illustrating an example of a coating liquid pan angle automatic setting device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A coating device, a coating method, and a coating film production method according to embodiments of the present invention will now be described in detail with reference to the accompanying drawings. The individual embodiments described below will be useful for understanding various concepts, such as higher-level concepts, middle-level concepts, and lower-level concepts, of the present invention. However, the components described in the embodiments are merely examples, and the technical scope of the present invention is established by the claims, and is not limited by the individual embodiments described below.

[0015] Fig. 1 is a schematic cross-sectional view showing the overall configuration of a coating device according to an embodiment of the present invention, Fig. 2 is a perspective view of the main parts of the coating device shown in Fig. 1, and Fig. 3 is a plan view seen from above of the main parts of the coating device shown in Fig. 1. Fig. 4 is a perspective view of the main parts of the coating device shown in Fig. 1, showing the flow of a coating liquid. Fig. 1 is a side cross-sectional view taken along line II' in Fig. 2. The coating device 1 applies a coating liquid such as paint to a sheet-like substrate 4 such as a web or film via a coating roll 3 such as a gravure roll, i.e., forms a wet coating film of the coating liquid on the surface of the substrate 4. A direct method is one in which the coating roll 3 moves in the same direction as the running direction of the substrate 4, and a reverse method is one in which the coating roll 3 moves in the opposite direction. There are also methods in which a backup roll (not shown) is installed in a position where it is pressed against the coating roll 3, and a kiss method in which there is no backup roll, and the present invention is effective for any of these methods.

[0016] The coating device 1 comprises a coating fluid supply unit 5 provided at one end of a coating fluid pan 2 and discharging coating fluid 10 through a slit 7 provided in a direction along the rotation axis 3a of the coating roll 3, i.e., along the longitudinal direction of the coating roll 3, a coating fluid pan 2 for storing the discharged coating fluid 10, a coating fluid outlet unit 14 provided at a position vertically lower than the coating fluid supply unit 5 at the other end of the coating fluid pan facing the one end of the coating fluid pan 2 across the coating roll 3, and discharging coating fluid that overflows from the coating fluid pan 2, and a coating fluid pan angle adjustment unit 20 that can adjust the angle of a slope from a bottom 12 of the coating fluid pan 2 facing the coating roll 3 to the coating fluid outlet unit 14 relative to a horizontal plane in a cross section perpendicular to the longitudinal direction of the coating roll 3 as shown in FIG. 1.

[0017] 4, the coating fluid discharged from the coating fluid supply unit 5 flows into and accumulates in the coating fluid pan 2, immersing the lower part of the coating roll 3. The coating fluid overflowing from the coating fluid pan 2 flows through a coating fluid outlet unit 14 composed of flat guide plates 14a and 14b, and is accumulated in a liquid receiving tank 16. Guide plate 14a is gently inclined downward from the other end of the coating fluid pan 2 toward the liquid receiving tank 16, and guide plate 14b is inclined almost vertically downward from the end of guide plate 14a on the liquid receiving tank 16 side toward the liquid receiving tank 16.

[0018] The coating liquid stored in the liquid receiving tank 16 is supplied to a filter 32 through an opening 16a provided at the bottom of the liquid receiving tank 16 and a pipe 31, where it is filtered, and then sent to a pump 36 through a pipe 33, and then supplied again to the coating liquid supply unit 5 through a pipe 37. Note that between the filter 32 and the pump 36, a device may be provided for stirring the coating liquid supplied from the filter 32, adjusting the viscosity, adjusting the concentration of particulate matter and the like contained in the coating liquid, and the like.

[0019] The coating liquid 10 may contain particulate matter having a relatively high specific gravity relative to the coating liquid, such as particles of a matting agent, an antibacterial agent, an antifungal agent, an antiviral agent, etc. In such a case, if the particulate matter settles and accumulates at the bottom of the coating liquid pan over time, problems such as a decrease in the concentration of the particulate matter in the coating film of the coating liquid transferred to the substrate via the coating roll occur. Furthermore, if the concentration of the particulate matter in the liquid pool of the coating liquid pan is not uniform along the longitudinal direction of the coating roll, the concentration of the particulate matter in the coating film transferred to the substrate via the coating roll will be non-uniform along the longitudinal direction, which will ultimately result in non-uniform quality of the coating product.

[0020] The coating fluid supply unit 5, the coating fluid pan 2, and the coating fluid pan angle adjustment unit 20 of the coating device 1, which are configured to prevent the occurrence of such problems, will be described in detail below. An example of the configuration of the coating liquid supply unit 5 will be described with reference to Fig. 5. Fig. 5(a) is a side cross-sectional view of the coating liquid supply unit 5 taken along line II' in Fig. 2, (b) is a perspective view of the coating liquid supply unit 5, and (c) is a perspective view showing a modified example of the coating liquid supply unit 5.

[0021] The coating fluid supply unit 5 is configured with a housing 6 having, for example, a rectangular prism (rectangular parallelepiped) shape with its long sides aligned along the longitudinal direction (Y direction) of the coating roll 3, and a liquid storage unit (tank) 39 having, for example, a rectangular prism (rectangular parallelepiped) shape with its long sides aligned along the Y direction is provided therein. A pipe 37 connected to a pump 36 is branched into a plurality of, preferably four or more (four in this example) pipes 37a to 37d arranged at equal intervals along the Y direction. These branch pipes 37a to 37d penetrate a side plate 6a of the housing 6, and their outlets 38a to 38d penetrate an upper plate 39a of the liquid storage unit 39 and open into the liquid storage unit 39.

[0022] An opening 39c extending along the Y direction is provided at a position midway in the X direction of side plate 39b of liquid storage portion 39, and a passage 40 is formed that extends along the Y direction from opening 39c and reaches side plate 6a of housing 6 in the Z direction. Here, the lower portion of passage 40 from opening 39c to the middle of passage 40 in the Z direction is tapered, forming tapered portion 40a. In this way, the liquid reservoir 39 communicates with a passage 40 having a tapered portion 40a, and further communicates with a slit 7 formed in the side plate 6b. The slit 7 is formed in a portion of the side plate 6b excluding both ends along the longitudinal direction (Y direction) so as to face the coating roll 3, and the length of the slit 7 in the Y direction is set to be equal to or longer than the length of the coating roll 3 in the Y direction. In other words, both ends of the slit 7 in the longitudinal direction are configured to extend outward beyond both ends of the coating roll 3 in the longitudinal direction.

[0023] With this configuration, the coating liquid supplied from the openings 38a to 38d of the branch pipes 37a to 37d is stored in the liquid reservoir 39, and the coating liquid overflowing from the liquid reservoir 39 is discharged from the slit 7 via the tapered portion 40a and the passage 40, and flows into the coating liquid pan 2. The coating liquid is discharged from multiple pipes 37a to 37d arranged at equal intervals along the Y direction and stored in the liquid reservoir 39, so that the coating liquid is discharged from the slit 7 at a continuous, uniform flow rate along the longitudinal direction of the coating roll 3, and the concentration of granular matter in the coating liquid is also uniform along the longitudinal direction.

[0024] Here, the inclination angle δ of the tapered portion 40a with respect to the horizontal plane H (see FIG. 5(a)) is in the range of about 10 to 60 degrees, preferably about 15 to 25 degrees, and more preferably about 20 degrees. By tapering the vicinity of the inlet of the passage 40 (near the opening 39c) in this manner, the coating liquid and the granular matter therein can be easily discharged from the liquid reservoir 39 to the passage 40 smoothly. On the other hand, if the inclination angle δ is less than about 10 degrees or more than about 60 degrees, the coating liquid will be retained in the liquid reservoir 39 and the granular matter will be easily settled over time. In particular, if the tapered portion 40a is not provided, i.e., if the inclination angle δ of the tapered portion 40a with respect to the horizontal plane is set to approximately 0 degrees, the coating liquid will be more easily retained in the liquid reservoir 39 and the granular matter will be easily settled over time.

[0025] The width of the slit 7 in the X direction (the direction perpendicular to the longitudinal direction of the coating roll) is in the range of about 0.6 mm to 2.5 mm, preferably about 0.8 mm to 1.5 mm, and more preferably about 1 mm. By setting it in this range, unevenness in the flow rate of the coating liquid in the X direction when the coating liquid is discharged from the slit 7 is suppressed and made uniform. On the other hand, if it is less than about 0.6 mm, clogging of the coating liquid is likely to occur in the passage 40 and the slit 7, and if it exceeds about 2.5 mm, unevenness in the flow rate of the coating liquid in the X and Y directions is likely to occur.

[0026] Next, the inclination angle of the coating fluid supply unit 5 with respect to the horizontal plane H will be described with reference to Fig. 6. Fig. 6(a) is a side cross-sectional view of the coating fluid supply unit 5 taken along line II' in Fig. 2, showing a state in which the coating fluid supply unit 5 is slightly inclined with respect to the horizontal plane H, and Fig. 6(b) is a schematic perspective view of the coating fluid supply unit 5 and the coating fluid supply unit tilting device 50. During coating operation, it is preferable that the coating fluid supply unit 5 is rotated from the horizontally placed state shown in FIG. 5(a) in the direction of the arrow (clockwise) as shown in FIG. 6(a) so that the inclination angle φ of the bottom plate 6c of the coating fluid supply unit 5 with respect to the horizontal plane H is appropriately set.

[0027] The inclination angle φ of the coating liquid supply section 5 is in the range of about 70 to 100 degrees, and preferably in the range of about 85 to 90 degrees. By setting the angle in this range, the passage 40 from the opening 39c to the slit 7 faces almost vertically downward, so that the coating liquid that flows into the liquid reservoir 39 is discharged more smoothly without stagnation in the liquid reservoir 39, and thus the granular matter can be more effectively prevented from stagnation and settling in the liquid reservoir 39. Therefore, the coating liquid in which the granular matter is uniformly dispersed along the longitudinal direction (Y direction) can be supplied from the slit 7 to the coating liquid pan 2, and the concentration of the granular matter in the coating liquid in the coating liquid pan 2 can be made more uniform in the longitudinal direction (Y direction), and the coating liquid can be homogenized. Even when the inclination angle φ of the coating liquid supply section 5 is set in this manner, it is preferable to set the inclination angle δ of the tapered section 40a within the above-mentioned range, from the viewpoint of effectively preventing retention of the coating liquid and settling and accumulation of particulate matter.

[0028] In order to more effectively prevent the granular matter in the coating liquid from settling and accumulating in the liquid reservoir 39, the shape of the liquid reservoir 39 shown in Fig. 5(a), Fig. 6(a), etc. may be changed from a square prism (rectangular parallelepiped) shape to, for example, a circular shape when viewed from the Y direction of the upper plate (bottom plate) 6d, resulting in a cylindrical (columnar) shape as a whole. Alternatively, at least the corners 39t of the liquid reservoir 39 shown in Fig. 5(a), Fig. 6(a), etc. may be formed into an arc shape when viewed from the Y direction, as shown in the perspective view of Fig. 5(c). This makes it possible to more effectively prevent the coating liquid from accumulating at the corners 39t and the granular matter from settling, even when the inclination angle φ is set to a small value less than 90 degrees.

[0029] The coating fluid supply unit tilting device 50 for adjusting the tilt angle φ of the coating fluid supply unit 5 may be configured, for example, to have a built-in motor such as a step motor, rotate its drive shaft 51 by a desired angle by the motor, and rotate the coating fluid supply unit 5 fixed to the drive shaft 51 together with the rotation of the drive shaft 51 to adjust the tilt angle φ. Alternatively, the coating fluid supply unit tilting device 50 may be a known mechanism using a ratchet, rotate the central shaft 51 by a desired angle by the ratchet, and rotate the coating fluid supply unit 5 fixed to the central shaft 51 to adjust the tilt angle φ.

[0030] It is preferable that the inclination angle δ of the tapered portion 40a with respect to the horizontal plane, the width of the slit 7 in the X direction, the inclination angle φ of the coating liquid supply unit 5, etc. are appropriately set according to at least one of factors such as the viscosity of the coating liquid, the type and specific gravity of the granular material, the content ratio (weight ratio) of the granular material in the coating liquid, etc. That is, for example, the inclination angle δ of the tapered portion 40a with respect to the horizontal plane, the width of the slit 7 in the X direction, and the inclination angle φ of the coating liquid supply unit 5 are set larger as the viscosity of the coating liquid increases, the specific gravity of the granular material increases, and the content ratio (weight ratio) of the granular material in the coating liquid increases.

[0031] Next, a configuration example of the coating fluid pan 2 will be described with reference to Figs. 1, 2, 7, etc. The coating fluid pan 2 is rectangular in plan view as shown in Figs. 2 and 3, and is generally U-shaped in a cross section perpendicular to the longitudinal direction of the coating roll 3 as shown in Fig. 1, with the bottom 12 facing the coating roll 3 curved downward below the coating roll. The coating fluid pan 2 is composed of a first inclined surface 11 extending from the coating fluid supply section 5 to an upper end 12a (see Fig. 7(b)) of the bottom 12 on the coating fluid supply section 5 side, the bottom 12, and a second inclined surface 13 extending from an upper end 12b (see Fig. 7(b)) of the bottom 12 on the coating fluid outlet section 14 side to the coating fluid outlet section 14. The position of the boundary 11a between the first inclined surface 11 and the coating fluid supply section 5 is configured to be lower than the position of the boundary 13b between the second inclined surface 13 and the coating fluid outlet section 14. As shown in FIG. 2, the coating fluid pan 2 is provided with side walls 2a, 2b, and 2c on three sides except for the end on the side of the liquid receiving tank 16 to prevent leakage of the coating fluid.

[0032] An example of the shape of the coating fluid pan 2 will be described with reference to side cross-sectional views of the main parts of the coating fluid pan 2 taken along line II' in FIG. 2, shown in (a) and (b) of FIG. In the example shown in Fig. 7(a), in a cross section perpendicular to the longitudinal direction of coating roll 3, coating fluid pan 2 is generally arc-shaped, and the curvature of bottom 12 is approximately the same as or smaller than the curvature of coating roll 3. The curvatures of first inclined surface 11 and second inclined surface 13 are approximately the same and approximately the same as or smaller than the curvature of bottom 12, and furthermore, smaller than the curvature of coating roll 3. As an example, when coating roll 3 has a diameter of approximately 200 mm, the diameter of liquid reservoir 30 of coating fluid pan 2 (the portion where coating fluid 10 accumulates in Fig. 7(a)) is approximately 250 mm. On the other hand, increasing the overall curvature of the coating fluid pan 2, particularly the curvature of the first inclined surface 11 and the second inclined surface 13, undesirably increases the volume of the liquid reservoir 30, causing stagnation of the coating fluid in the liquid reservoir 30 and ultimately settling and accumulation of granular matter over time (part 30a in (a) of Figure 7).

[0033] In the example shown in Fig. 7(b), in a cross section perpendicular to the longitudinal direction of coating roll 3, first inclined surface 11 and second inclined surface 13 of coating fluid pan 2 are linear, and the shape of bottom 12 is the same as that of Fig. 7(a). When the coating device is on standby for a coating operation (initial time), that is, when coating fluid pan 2 alone is installed horizontally (initial state), the allowable ranges of inclination angle α1 of first inclined surface 11 with respect to horizontal plane H and inclination angle α2 of second inclined surface 13 with respect to horizontal plane H are approximately 3 to 30 degrees, preferably approximately 12 to 20 degrees, and more preferably about 16 degrees. The inclination angle α2 of the second inclined surface 13 with respect to the horizontal plane H is preferably set appropriately depending on at least one of factors such as the viscosity of the coating liquid, the type (specific gravity) of the granular material, the content ratio (weight ratio) of the granular material in the coating liquid, the groove depth of the coating roll 3, the coating film thickness on the substrate, the line speed, etc. That is, for example, the inclination angle α2 of the second inclined surface 13 with respect to the horizontal plane is set to be smaller as the viscosity of the coating liquid increases, the specific gravity of the granular material increases, the content ratio (weight ratio) of the granular material in the coating liquid increases, the groove depth of the coating roll 3 decreases, the coating film thickness on the substrate decreases, and the line speed decreases.

[0034] In either of the coating fluid pans 2 in Figure 7(a) and (b), the coating fluid discharged from the coating fluid supply section 5 can be smoothly supplied to the fluid reservoir 30 of the coating fluid pan 2, and the coating fluid in the fluid reservoir 30 can be smoothly and sequentially discharged via the coating fluid outlet section 14, thereby preventing the coating fluid from stagnation in the fluid reservoir 30 and, ultimately, the settling and accumulation of granular matter over time. From the viewpoint of preventing retention of the coating liquid and settling and accumulation of particulate matter at the bottom 12, it is more preferable that the second inclined surface 13 on the outflow side be linear as shown in Fig. 7(b). Therefore, the first inclined surface 11 on the inflow side may be curved, and the second inclined surface 13 on the outflow side may be linear.

[0035] When the coating device is waiting for a coating operation (initial time), that is, when the coating pan 2 is installed horizontally, the vertical distance (height) h1 (see FIG. 7(a)) from the bottom 12 of the coating pan 2 to the boundary 13b with the coating liquid outlet 14 of the second inclined surface 13 is in the range of about 10 to 30 mm, preferably about 12 to 20 mm, and more preferably about 15 mm. If it is less than about 10 mm, the coating roll 3 cannot be sufficiently immersed, and a satisfactory coating liquid cannot be transferred to the substrate to form a coating film. On the other hand, if the distance exceeds about 30 mm, the volume of the liquid pool increases, which results in the coating liquid being easily retained and the granular matter being easily settled, and furthermore, the amount of waste liquid in the coating pan 2 after the coating operation is completed increases. The distance h1 is preferably set appropriately depending on at least one of factors such as the viscosity of the coating liquid, the type of granular material (specific gravity), the content ratio (weight ratio) of the granular material in the coating liquid, the groove depth of the coating roll 3, the coating thickness on the substrate, the line speed, etc. That is, for example, the higher the viscosity of the coating liquid, the higher the specific gravity of the granular material, the higher the content ratio (weight ratio) of the granular material in the coating liquid, the shallower the groove depth of the coating roll 3, the thinner the coating thickness on the substrate, and the slower the line speed, the shorter the distance h1 is set.

[0036] The vertical distance h2 (see FIG. 7(b)) between the bottom 12 of the coating liquid pan 2 and the bottom of the coating roll 3 is in the range of about 8 to 20 mm, preferably about 10 to 15 mm, and more preferably about 13 mm. If it is less than about 8 mm, the flow of the coating liquid to the outflow side is poor, and the coating liquid is likely to stagnate at the bottom 12. On the other hand, if it exceeds about 20 mm, the volume of the liquid pool 30 will be large, and the coating liquid will be likely to stagnate, and further, granular matter will be likely to settle and accumulate over time. The distance h2 is preferably set appropriately depending on at least one of factors such as the viscosity of the coating liquid, the type (specific gravity) of the granular material, the content ratio (weight ratio) of the granular material in the coating liquid, etc. That is, for example, the higher the viscosity of the coating liquid, the higher the specific gravity of the granular material, or the higher the content ratio (weight ratio) of the granular material in the coating liquid, the smaller the distance h2 is set.

[0037] The immersion depth (vertical length of immersion) h3 (see FIG. 7(b)) of the bottom of the coating roll 3 into the liquid pool 30 is about 1 to 20 mm, preferably about 1 to 5 mm, and more preferably about 2 mm. If it is less than about 1 mm, the immersion of the coating roll 3 is insufficient, and a sufficient amount of the coating liquid cannot be transferred to the substrate to form a coating film, and there is a risk of coating film loss or the like occurring. On the other hand, if the distance exceeds about 20 mm, the volume of the liquid pool 30 must be increased, which makes it easier for the coating liquid to stagnate and, ultimately, for particulate matter to settle and accumulate over time. The immersion depth h3 is preferably set appropriately depending on at least one of factors such as the viscosity of the coating liquid, the type (specific gravity) of the granular material, the content ratio (weight ratio) of the granular material in the coating liquid, the line speed, etc. That is, for example, the immersion depth h3 is set to be larger as the viscosity of the coating liquid increases, the specific gravity of the granular material increases, the content ratio (weight ratio) of the granular material in the coating liquid increases, and the line speed increases, thereby preventing coating loss and the like.

[0038] Next, a schematic configuration of one example of coating fluid pan angle adjustment section 20 that adjusts the tilt angle of coating fluid pan 2 will be described with reference to FIGS. 1 and 3. FIG. 1, the coating fluid pan angle adjustment unit 20 is composed of a support base 26 that supports the coating fluid pan 2, a handle 21 for performing the rotation operation, a known rotation / linear movement mechanism 22 that converts the rotation operation of the handle 21 into linear movement in the +Z and -Z directions, a link 24 that moves linearly in the +Z and -Z directions in response to the linear movement of the rotation / linear movement mechanism 22 in response to the rotation operation of the handle 21, and an arm 25 having one end pivotally supported by the link 24 and the other end connected to the support base 26. The support base 26 is capable of swinging about a rotation shaft 27 that is aligned along the longitudinal direction (Y direction) of the coating roll 3 as the center of rotation.

[0039] The operation of coating fluid pan angle adjustment unit 20 will be described with reference to Figures 1, 3, and 8. Figures 8(a), (b), and (c) are side cross-sectional views taken along line II' in Figure 2, showing the configuration of the main parts of coating fluid pan 2, coating fluid pan angle adjustment unit 20, and the like. When an operator rotates handle 21, link 24 moves linearly in the +Z or -Z direction via rotation / linear mechanism 22, and coating fluid pan 2 accordingly swings clockwise or counterclockwise in Figures 1 and 8. For example, when the coating device is on standby for a coating operation (initial time), that is, when coating fluid pan 2 is installed horizontally by itself, handle 21 is in the initial position and arm 25 is in a position where its longitudinal direction coincides with vertical direction V, as shown in Figure 8(a), and therefore angle θ between the longitudinal direction of arm 25 and vertical direction V is 0 degrees.

[0040] 8(b), when the handle 21 is rotated clockwise from the initial position, the link 24 moves linearly, for example, in the -Z direction, and the arm 25 rotates clockwise by an angle θ=θ1 accordingly. As a result, the coating fluid pan 2 also rotates clockwise by an angle θ=θ1, and the second inclined surface 13 also rotates clockwise by the same angle θ=θ1. Conversely, when handle 21 is rotated counterclockwise, as shown in (c) of Figure 8, link 24 moves straight in the +Z direction, and accordingly arm 25 rotates counterclockwise by angle θ = θ2, so that second inclined surface 13 also rotates counterclockwise by the same angle θ = θ2 as arm 25. The coating fluid pan 2 shown in FIG. 8 is an example in which the first inclined surface 11 and the second inclined surface 13 of the coating fluid pan 2 are linear as shown in FIG. 7(b).

[0041] In this way, the tilt angle θ of arm 25 with respect to vertical direction V, and therefore the tilt angles of first inclined surface 11 and second inclined surface 13 of coating fluid pan 2, can be arbitrarily adjusted by rotating handle 21. Note that, to clarify the correspondence between the rotational position of handle 21 and the tilt angle θ of coating fluid pan 2, as one example, a scale indicating the tilt angle θ of coating fluid pan 2 may be displayed at the rotational position of handle 21, allowing the operator to easily adjust the tilt angle of coating fluid pan 2.

[0042] The inclination angle θ of coating fluid pan 2, which is adjusted (changed) from the initial state by coating fluid pan angle adjustment unit 20, is normally set to 0 degree when the coating device is waiting for a coating operation (initial state), and is set to, for example, within a range of about 2 to 14 degrees during a coating operation. Therefore, during a coating operation, the inclination angle of second inclined surface 13 of coating fluid pan 2 with respect to the horizontal plane is α2+θ, and is normally set within a range of about 5 to 44 degrees. The inclination angle θ of the coating fluid pan 2, which is adjusted (changed) from the initial state by the coating fluid pan angle adjustment unit 20, is preferably set appropriately during the coating operation depending on at least one of factors such as the viscosity of the coating fluid, the type (specific gravity) of the granular material, the content ratio (weight ratio) of the granular material in the coating fluid, the groove depth of the coating roll 3, the coating film thickness on the substrate, the line speed, etc. That is, for example, the inclination angle α2+θ of the second inclined surface 13 of the coating fluid pan 2 with respect to the horizontal plane is set to be smaller as the viscosity of the coating fluid increases, the specific gravity of the granular material increases, the content ratio (weight ratio) of the granular material in the coating fluid increases, the groove depth of the coating roll 3 decreases, the coating film thickness on the substrate decreases, and the line speed decreases.

[0043] In this way, by making it possible to adjust (change) the inclination angle θ of the coating fluid pan 2 from the initial state using the coating fluid pan angle adjustment unit 20, the inclination angle α2+θ of the second inclined surface 13 of the coating fluid pan 2 with respect to the horizontal plane can be adjusted, and in turn, the volume of the liquid reservoir 30 of the coating fluid pan 2 and the vertical distance (height) h1 from the bottom 12 to the boundary portion 13b with the coating fluid outlet portion 14 of the second inclined surface 13 can be appropriately adjusted within the above-mentioned range in accordance with at least one of the above-mentioned factors. That is, for example, the inclination angle α2+θ is adjusted so that the distance h1 is within the above-mentioned range of about 10 to 30 mm in accordance with at least one of the above-mentioned factors.

[0044] The configuration of coating fluid pan angle adjustment unit 20 is not limited to the above. The schematic configuration of modified examples of the coating fluid pan angle adjustment unit will be described with reference to Fig. 9 and Fig. 10. Fig. 9 is a side cross-sectional view taken along line II' in Fig. 2, showing the configuration of the main parts of modified example 20A of coating fluid pan angle adjustment unit, and Fig. 10 is a plan view of the main parts, as viewed from above, of the coating device when modified example 20A of coating fluid pan angle adjustment unit is applied to the coating device shown in Fig. 1. 9 and 10, coating fluid pan angle adjustment unit 20A has a support base 26 that supports coating fluid pan 2, a rotation shaft 27 that rotatably supports support base 26, a pair of bolts (push bolts) 29a, 29b, and a bolt holder 28 having a pair of through holes through which bolts 29a, 29b pass and into which they are respectively screwed. The upper ends of bolts 29a, 29b abut against the lower surface of support base 26.

[0045] In the coating fluid pan angle adjustment unit 20A configured in this manner, the inclination angle of the coating fluid pan 2 can be adjusted by turning the bolt to move it (up and down) in the +X or -X direction. For example, in FIG. 9, by turning and moving the bolt 29a in the +X direction, the support table 26 can be rotated clockwise around the rotation axis 27 as the center of rotation, and the coating fluid pan 2 can be similarly rotated clockwise. The same can be achieved by turning and moving the bolt 29b in the -X direction. In this manner, the inclination angle (α2+θ) of the second inclined surface 13 of the coating fluid pan 2 with respect to the horizontal plane can be appropriately adjusted by adjusting the height position of the bolt 29a or 29b. Although one pair of bolts is used, two or more pairs may be used.

[0046] In coating fluid pan angle adjustment units 20, 20A, as described above, the angle of coating fluid pan 2 is adjusted by an operator manually operating handle 21 or bolts 29a, 29b, but the angle of coating fluid pan 2 may be set automatically depending on at least one of factors such as the viscosity of the coating fluid, the type of granular material (specific gravity), the proportion of granular material in the coating fluid (weight ratio), the groove depth of coating roll 3, the coating film thickness on the substrate, and the line speed.

[0047] Fig. 11 is a schematic diagram of an example of such an automatic coating fluid pan angle setting unit 70. In the automatic coating fluid pan angle setting unit 70, a motor, for example, a step motor 73, is connected to the rotation / translation mechanism 22 in the coating fluid pan angle adjustment unit 20 shown in Fig. 1 etc., and the rotation of the motor 73 is controlled by a setting unit 71 and a control unit 72. The control unit 72 has a built-in memory such as a table in which data indicating the relationship between each of the above factors and the tilt angle θ of the coating fluid pan 2 (or the rotation angle of the motor's rotation shaft 74) is preset. When the operator selectively sets and inputs the above factors to the setting unit 71, the control unit 72 reads out data corresponding to the input factor from the memory and controls the motor 73 according to the read out data, thereby controlling the tilt angle θ to an appropriate angle as described above according to the set and input factor.

[0048] Using the coating device and coating method described above, a paint can be applied onto the surface of a sheet-like substrate such as a film to form a wet coating film, and the coating film can be cured by means of heat, ultraviolet light, electron beams, or the like to produce a cured coating film. The cured coating is produced in a thickness range of about 0.1 to 20 μm, preferably about 1 to 15 μm, and more preferably about 1 to 10 μm.

[0049] Although the embodiments of the present invention have been described above, various alternatives, modifications, and variations are possible for those skilled in the art based on the above description, and the present invention includes the above-mentioned various alternatives, modifications, and variations without departing from the spirit of the present invention. [Explanation of symbols]

[0050] 1 Coating device 2 Coating fluid pan 3 Coating roll 5 Coating fluid supply section 7 Slit 10 Coating fluid 14 Coating fluid discharge section 20 Coating fluid pan angle adjustment unit 39 Liquid reservoir

Claims

1. In a coating device that applies a coating liquid to a sheet-like substrate through a coating roll, a coating liquid supply unit provided at one end side of the coating liquid pan, the coating liquid being supplied from a plurality of pipes arranged along the longitudinal direction of the coating roll, temporarily storing the coating liquid in a liquid reservoir, and discharging the coating liquid overflowing from the liquid reservoir through a slit provided along the longitudinal direction of the liquid reservoir; a coating liquid pan for storing the discharged coating liquid, the coating liquid pan being generally U-shaped in a cross section perpendicular to the longitudinal direction of the coating roll, and having a bottom portion facing the coating roll that is curved downward; a coating liquid discharge section that is provided at a position lower than the coating liquid supply section at the other end side of the coating liquid pan that faces the one end side of the coating liquid pan via the coating roll, and that discharges the coating liquid that has overflowed from the coating liquid pan; and a coating fluid pan angle adjustment section that can adjust the angle of a slope extending from the bottom of the coating fluid pan to the coating fluid discharge section relative to a horizontal plane in a cross section perpendicular to the longitudinal direction of the coating roll.

2. 2. The coating device according to claim 1, wherein the coating liquid is a coating liquid containing granular matter, and the coating liquid pan angle adjustment unit is adjustable according to at least one of the following factors: viscosity of the coating liquid, type and specific gravity of the granular matter, content and weight ratio of the granular matter in the coating liquid, groove depth of the coating roll, coating thickness on the substrate, and line speed.

3. 3. The coating device according to claim 1, wherein in the coating liquid supply section, the liquid reservoir is provided along a longitudinal direction of the coating roll, the liquid reservoir has an opening provided along the longitudinal direction, and the opening communicates with the slit via a tapered passage provided along the longitudinal direction.

4. 4. The coating device according to claim 1, wherein a width of the slit in a direction perpendicular to the longitudinal direction of the coating roll is in a range of 0.6 mm to 2.5 mm, and a length of the slit in the longitudinal direction of the coating roll is equal to or greater than the length of the coating roll in the longitudinal direction.

5. 5. The coating device according to claim 1, wherein a vertical distance (h1) from a bottom of the coating fluid pan to the coating fluid discharge portion is in the range of 10 to 30 mm.

6. 6. The coating device according to claim 1, wherein the inclined surface extending from a bottom of the coating fluid pan to the coating fluid discharge portion is linear in the cross section, and an angle of the inclined surface with respect to a horizontal plane in an initial state in which the coating fluid pan is installed horizontally is in a range of 3 to 30 degrees.

7. 7. The coating apparatus according to claim 1, wherein a curvature of a bottom of the coating fluid pan is smaller than a curvature of the coating roll.

8. 8. The coating device according to claim 1, wherein a first inclined surface extending from the coating fluid supply section to the bottom of the coating fluid pan and a second inclined surface extending from the bottom of the coating fluid pan to the coating fluid discharge section are both arc-shaped in the cross section, and the curvatures of the first inclined surface and the second inclined surface are smaller than the curvature of the bottom of the coating fluid pan.

9. 9. The coating apparatus according to claim 1, wherein a vertical distance (h2) from a bottom of the coating fluid pan to a bottom of the coating roll is in the range of 8 to 20 mm.

10. 10. The coating device according to claim 1, wherein a vertical length (h3) of a bottom of the coating roll immersed in the puddle of the coating liquid in the coating liquid pan is in the range of 1 to 20 mm.

11. A coating method in which a coating liquid is applied to a sheet-like substrate via a coating roll, At one end side of the coating liquid pan, the coating liquid supplied from a plurality of pipes arranged along the longitudinal direction of the coating roll is temporarily stored in a liquid reservoir, and the coating liquid overflowing from the liquid reservoir is discharged through a slit provided along the longitudinal direction of the liquid reservoir, The discharged coating liquid is stored in the coating liquid pan, which has a generally U-shaped cross section perpendicular to the longitudinal direction of the coating roll and a bottom portion facing the coating roll that is curved downward; Discharge the coating liquid overflowing from the coating liquid pan at the other end side of the coating liquid pan opposed to the one end side of the coating liquid pan via the coating roll; In a cross section perpendicular to the longitudinal direction of the coating roll, an angle of a slope extending from a bottom of the coating liquid pan to the other end side with respect to a horizontal plane is adjustable; This makes it possible to vary the volume of the coating fluid stored in the coating fluid pan and the vertical distance from the bottom of the coating fluid pan to the other end.

12. A method for producing a coating comprising the steps of: A method comprising the step of forming a wet coating film of a coating liquid on a surface of a sheet-like substrate by using a coating device according to any one of claims 1 to 10.

13. A method for producing a coating comprising the steps of: A method comprising the step of forming a wet coating of a coating fluid on a surface of a sheet-like substrate by using a coating method according to claim 11.

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