Patent Application
20250041885
The present invention relates to a slot-type spray nozzle, a coating device using the slot-type spray nozzle, and a manufacturing method of a film-coated member using the coating device.
Conventionally, as devices for applying coating fluid to a substrate to be coated (hereinafter, also simply referred to as a “substrate”), spray coating devices are known which spray coating fluid after forming droplets of the coating fluid by a spray nozzle (hereinafter, also simply referred to as a “nozzle”).
In these spray coating devices, from the viewpoint of productivity and functionality of the substrate, it is often desired to form a thin coating film having a uniform thickness on substantially the entire surface of a wide substrate.
As a coating unit in such a case, for example, Patent Literature 1 discloses a spray coating device that forms a thin coating film on a wide substrate, the spray coating device in which a plurality of two-fluid single-hole type spray nozzles, capable of forming a thin film by discharging compressed air simultaneously with coating fluid, micronizing the coating fluid by a strong striking force (collision force with the coating fluid) of the discharged air, and spraying the coating fluid, is arrayed at equal intervals in a width direction of a substrate, by conveying the substrate while spraying the coating fluid simultaneously such that the coating fluid sprayed from the nozzles overlaps. However, in this spray coating device, since each nozzle is an independent component, variations in spray state are likely to occur due to individual differences of the nozzles, namely, the variation in shape among the nozzles. In addition, since the discharged air and the coating fluid droplets sprayed from each nozzle fly while expanding in the width direction in the form of a fan shape, a cone shape, or the like, application stripes are likely to occur due to interference at portions where the application overlaps between the nozzles, and it is difficult to form a uniform coating film.
To address the disadvantage of such a single-hole type nozzle, as a two-fluid type spray nozzle capable of widely, thinly, and uniformly applying a coating film, Patent Literature 2 discloses a slot-type spray nozzle having a plurality of coating fluid discharge ports in an application width direction of a substrate and a pair of air discharge ports arranged in such a manner as to sandwich the coating fluid discharge ports that are continuously or intermittently opened over the width direction in the vicinity of the coating fluid discharge ports. The spray nozzle discharges the coating fluid to generate a coating fluid pool exposed at the distal end of the coating fluid discharge port and instantaneously repeats an operation of applying a striking force of discharged air to the coating fluid pool to separate the coating fluid pool from the spray nozzle, thereby enabling generation of fine coating fluid droplets. In addition, since the spray nozzle has a single nozzle over the application width, the variation in the shape at each coating fluid discharge port can be suppressed as compared with those in a single-hole type nozzle, and the coating fluid can be sprayed with high uniformity in the application width direction. Furthermore, since air having a single band shape substantially continuous over the width direction of a substrate is discharged, the discharged air and the coating fluid droplets are sprayed in a direction substantially perpendicular to the width direction, the interference between the coating fluid discharge ports is reduced, and an extremely uniform thin coating film can be formed on the substrate.
However, even in the case of the slot-type spray nozzle disclosed in Patent Literature 2, straightness of the coating fluid droplets may be altered after being sprayed, thereby resulting in coating film unevenness. This is mainly because the flow of air present around the spray nozzle is excited by the drawing effect of a jet which is a viscous fluid, and the flight of the coating fluid droplets are affected by the interference by the drawn ambient air. In particular, a slot-type spray nozzle that discharges substantially continuous band-shaped air tends to have a larger discharged air flow rate than a structure in which a plurality of two-fluid single-hole type nozzles is arranged, and as the discharged air flow rate is larger, the ambient air outside the nozzle is drawn, and thus the flow of the discharged air is likely to be disturbed.
Meanwhile, to reduce the influence of the ambient air, it is only required to reduce the discharged air flow rate. However, in a case where the discharged air flow rate is reduced, there is a disadvantage that fine coating fluid droplets are not formed and that a thin coating film cannot be formed since a sufficient striking force cannot be applied to the coating fluid pool generated at the distal end of the coating fluid discharge port and the coating fluid pool cannot be separated from the nozzle unless the coating fluid pool grows to a certain extent.
The present invention has been made in view of the above disadvantage and provides a spray nozzle capable of forming fine coating fluid droplets even in a case where a discharged air flow rate is reduced and uniformly forming a thin coating film on a wide substrate. Furthermore, a spray coating device using the spray nozzle and a manufacturing method of a film-coated member using the spray coating device are provided.
In order to solve the above-described problem, a slot-type spray nozzle according to the present invention includes: a plurality of coating fluid discharge ports arranged in one direction; and a pair of air discharge ports continuously or intermittently opened in a vicinity of the coating fluid discharge ports in a width direction, the width direction being the one direction, the air discharge ports being arranged to sandwich the coating fluid discharge ports, the air discharge ports being formed in such a manner that air discharged from the air discharge ports obliquely intersects with a discharge direction of coating fluid, in which the slot-type spray nozzle further includes a pair of fluid holding surfaces extending in the discharging direction of the coating fluid from sides forming both ends in the width direction of the coating fluid discharge ports, the fluid holding surfaces facing each other across the coating fluid discharge ports, and with a length of the fluid holding surfaces in the discharge direction of the coating fluid denoted by H1 (μm), an angle (acute angle) formed by a discharge direction of the air discharged from an air discharge port and the discharge direction of the coating fluid denoted by θ (degrees), and an interval between the coating fluid discharge ports and the air discharge port denoted by L2 (μm),
(L2/tan θ)−100≤H1≤L2/tan θ (1).
The slot-type spray nozzle according to the present invention preferably has the following embodiments.
A coating device according to the present invention includes: the slot-type spray nozzle according to the present invention; a supply unit configured to supply the coating fluid and the air to the slot-type spray nozzle; a support unit configured to support a to-be-coated member; and a moving unit configured to relatively move the to-be-coated member supported by the support unit with respect to the slot-type spray nozzle.
A manufacturing method of a film-coated member according to the present invention includes: using the coating device according to the present invention; discharging the coating fluid from the coating fluid discharge ports while discharging the air from the air discharge ports; and spraying the coating fluid onto the to-be-coated member supported by the support unit to manufacture a member on which a coating film is formed.
It is preferable that the manufacturing method of a film-coated member according to the present invention in which an air flow rate discharged from the air discharge ports is within a range of 900 NL/min to 1500 NL/min per width of 1 m.
In this patent application, the “width direction” means a direction in which a plurality of coating fluid discharge ports are arranged.
By using a slot-type spray nozzle of the present invention, a coating film can be formed thinly, widely, and uniformly on a substrate.
As a result of intensive studies on the above disadvantages, the present inventors have found that coating fluid droplets are micronized by being separated from a spray nozzle in a state where a coating fluid pool generated at the distal end of the nozzle is small. More specifically, the present invention has been devised since it has been found that the uniformity of the coating film is improved by reducing the discharged air flow rate to mitigate deterioration of the straightness at the time when the coating fluid droplets fly while the state in which a thin film can be formed is maintained due to a fact that the coating fluid droplets are micronized by matching the position at which a coating fluid pool is separated with the position at which the striking force of the discharged air is obtained and reducing a contact area between the coating fluid pool and a nozzle surface.
Note that the gas component of air or the outside air used in the present invention is not particularly limited as long as it is a gas suitable for coating, and air, nitrogen gas, or the like can be used. The ambient pressure of the outside air is not particularly limited and can be subjected to an atmospheric pressure environment, a reduced pressure environment, or the like.
The coating fluid used for spray coating is not particularly limited, and examples thereof include solutions of inorganic substances or organic substances, slurries in which inorganic substances or organic substances are dispersed in a binder and a solvent, or the like. The viscosity of the coating fluid is required to be low enough to micronize the coating fluid by the striking force of the discharged air and is generally preferably less than or equal to 500 mPa·s.
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Note that the following description is given to facilitate understanding of the present invention and does not limit the present invention in any way. The scope of rights of the present invention is not limited to the following embodiments but includes all modifications within the scope equivalent to the structures described in the claims.
Next, in the vicinity of the coating fluid discharge ports 31, a pair of air discharge ports 33a and 33b each having a slit shape and an air discharge width W3 is arranged in such a manner as to sandwich the coating fluid discharge ports 31. Incidentally, the air discharge width W3 is longer than the coating fluid discharge width W1 in order to uniformly micronize the whole coating fluid discharged from the coating fluid discharge ports 31 by the striking force of the air. Note that the air discharge ports 33a and 33b may be each opened in one slit continuous in the width direction as illustrated in
In this spray nozzle 10, coating fluid F is discharged from a coating fluid discharge port 31 illustrated in
The supply conditions of the air G discharged from the air discharge ports 33a and 33b cannot be generally defined depending on a desired type of coating fluid, a desired coating film thickness, and others; however, from the viewpoint of minimizing the air flow rate to be used while maintaining the striking force for micronizing droplets and the viewpoint of minimizing disturbance of the discharged air flow, the pressure measured in the air manifolds 17a and 17b is preferably approximately in a range of 50 kPa to 200 kPa, and the air flow rate is preferably within a range of 900 NL/min to 1500 NL/min per air discharge width of 1 m.
As illustrated in
In the case of the conventional spray nozzle not including the fluid holding surfaces illustrated in
An example of a preferred embodiment of the spray nozzle will be described with reference to
As in a spray nozzle 10 illustrated in
It is preferable that a surface S (the same applies to the back surface) of a portion of the comb-shaped shim 12 protruding from a nozzle block illustrated in
The fluid holding surfaces 35L and 35R are desirably substantially orthogonal to the width direction. If the fluid holding surfaces 35L and 35R do not spread towards the end in the fluid discharge direction, the interval between the nozzle tips 36L and 36R does not expand, and thus the coating fluid can be stably bridged and held. In addition, if the fluid holding surfaces 35L and 35R are not narrowed towards the end in the fluid discharge direction, the coating fluid does not spread onto the surface S, and generation of the coating fluid droplets is stabilized. Since the fluid holding surfaces 35L and 35R are substantially orthogonal to the width direction, the coating fluid discharged from the coating fluid discharge ports 31 can be stably bridged and held. It is also possible to reduce the variation in the ejection direction of the coating fluid droplets when a coating fluid pool is separated by the striking force of the discharged air. Incidentally, the term “substantially orthogonal” means that an error in manufacturing is allowed and that an angle formed by a normal line of the fluid holding surface 35L or 35R and the width direction is less than or equal to 5 degrees.
It is preferable that the radiuses of curvature of the ridge lines of the distal ends 36L and 36R of the fluid holding surfaces 35L and 35R, respectively, are less than or equal to 30 μm. Since the smaller the radiuses of curvature are, the more stable the separation of the coating fluid pool at the ridge portions is, the variation in the ejection direction of the coating fluid droplets can be reduced when the coating fluid pool is separated by the discharged air.
An optimum value of a gap L1 of the coating fluid discharge ports 31 varies depending on the viscosity of the coating fluid in use and the flow rate of the coating fluid to be discharged; however, the gap L1 is preferably more than or equal to 50 μm from the viewpoint of reducing the variation in the shape of the discharge ports and is preferably less than or equal to 200 μm in order to make the coating fluid to be distributed from the coating fluid manifold to each of the coating fluid discharge ports uniform in the amount.
An interval L2 between the coating fluid discharge port 31 and the air discharge port 33a or 33b is preferably less than or equal to 100 μm. In a case where the interval L2 is less than or equal to 100 μm, the distance from the distal ends of the air discharge ports 33a and 33b to the striking force position is short, and thus the striking force of the air applied to the coating fluid can be sufficiently increased. In addition, since the length H1 of the fluid holding surface 35L (35R) can be made short, the coating fluid can be stably bridged and held.
A gap (for example, a gap L3) of each of the air discharge ports 33a and 33b is preferably less than or equal to 100 μm. In a case where the interval L3 is less than or equal to 100 μm, the average flow rate of the discharged air is sufficiently high, and the striking force of the air applied to the coating fluid is also sufficiently large, and thus the coating fluid droplets can be micronized. Furthermore, the amount of air for micronizing the coating fluid droplets can also be reduced.
The coating unit 80 includes the spray nozzle 10, a backup roll 81 which is a support unit of the substrate, a booth 82 covering around the spray nozzle 10 and the backup roll 81, a waste fluid collecting tank 83, and a decompression unit 84. The backup roll 81 supports the substrate being conveyed at an application location by the spray nozzle. In addition, the booth 82 has a substantially closed system closing the inside of the booth 82 except for an inlet opening 85, an outlet opening 86, and the like through which the substrate 40 passes and prevents scattering of the coating fluid droplets discharged from the spray nozzle 10 to the outside of the coating unit 80. A lower opening 87 of the booth communicates with the waste fluid collecting tank 83, and excessive coating fluid generated in the booth falls along slopes 88 in the booth and is collected in the waste fluid collecting tank 83 via the lower opening 87. In addition, a rear opening 89 of the booth is connected to the decompression unit 84 via an intake pipe 90. When the inside of the booth is brought into a reduced pressure environment by driving of the decompression unit 84, the outside air flows to the inside of the booth at the inlet opening 85 and the outlet opening 86, and thus scattering of the coating fluid discharged from the spray nozzle 10 to the outside of the booth can be prevented.
The supply unit 70 supplies the coating fluid to the spray nozzle 10 via a coating fluid pipe 73 by a coating fluid tank 71 and a metering pump 72. Moreover, air whose pressure has been adjusted by a compressed air source 74 and a pressure regulating valve 75 is supplied to the spray nozzle 10 via an air pipe 76 and a branch pipe 77.
The feed roll 61 as a moving unit is coupled to a driving unit (not illustrated). The substrate 40 is conveyed in the conveyance direction D at a desired conveyance speed by rotating the feed roll 61 by the drive unit.
With the spray coating device 60, a uniform coating film 41 can be formed on the substrate 40 being conveyed, and a film-coated member 43 can be manufactured. Note that a drying unit that dries the coating film 41 on the film-coated member 43 conveyed from the coating device 60 may be further included. A method of drying the coating film in the drying unit is not particularly limited, and a method of blowing a heat medium such as hot air, a heat oven method using a heater, or the like can be used.
The spray nozzle 10 of the present invention used in the spray coating device 60 can generate fine coating fluid droplets even at a low air flow rate that does not disturb the straightness of flying coating fluid droplets, and thus the film-coated member 43 coated with a thin film which is wide and has high uniformity in the width direction can be obtained.
Although the spray coating device 60 of
Examples will be described below; however, embodiments of the present invention are not limited to these examples.
Using the spray coating device illustrated in
In the spray nozzle, the coating fluid discharge width W1 was set to 1000 mm, the gap L1 of the coating fluid discharge ports was set to 100 μm, and the air discharge angle θ was set to 25°, and the air discharge ports were each set to have one slit shape in the width direction.
As for the coating fluid, a dispersion liquid in which a resist pigment was dispersed in propylene glycol monomethyl ether acetate (PMA) was used such that a solid content concentration was 14 mass % and a viscosity was 4.0 cp, and a spray flow rate of the coating fluid was set to 100 ml/min.
Whether or not a thin coating film can be formed by the spraying cannot be uniformly determined depending on desired spraying conditions such as the substrate conveyance speed or the flow rate of the coating fluid, and thus the comparison and evaluation were performed on the basis of the fineness of an average diameter of generated droplets.
Under each condition in Table 1, the diameter of the coating fluid droplet sprayed from the spray nozzle was measured using a laser diffraction type particle size distribution meter FLD-319A manufactured by Seika Digital Image CORPORATION. The measurement was performed by irradiating a coating fluid droplet group at a position 120 mm away from the spray nozzle distal end in the discharge direction with a laser beam in a direction orthogonal to the width direction of the spray nozzle and the discharge direction. The measured average droplet diameter was evaluated according to the following evaluation ranks. Incidentally, the Sauter mean diameter was used as the average droplet diameter.
◯: The average particle size of the coating fluid droplets is less than 30 μm.
x: The average particle size of the coating fluid droplets is greater than or equal to 30 μm.
Next, in order to evaluate the uniformity of a coating film, coating fluid was sprayed onto a PET film under each condition in Table 1 to form a coating film. The coating film thickness of the prepared coating film was measured at intervals of 10 mm in the width direction, and then the variation from the film thickness average value was calculated, whereby the coating film uniformity was evaluated depending on the following evaluation ranks. Note that the distance from the spray nozzle distal end to the substrate was set to 120 mm. The substrate was a PET film having a substrate width of 1000 mm and a thickness of 100 μm and was conveyed at a speed of 1 m/min.
Evaluation was performed with H1 of 40 μm, L2 of 50 μm, the shape of the fluid holding surface of being orthogonal, and an air discharge flow rate of 1200 NL/min per 1 m width. Both the average droplet diameter and the uniformity of the coating film thickness showed good results. Setting conditions and evaluation results in Example 1 are shown in Table 1.
Conditions were the same as those in Example 1 except that H1 was modified to 100 μm. Both the average droplet diameter and the uniformity of the coating film thickness showed good results. Setting conditions and evaluation results in Example 2 are shown in Table 1.
Conditions were the same as those in Example 2 except that the air discharge flow rate was increased to 1600 NL/min per 1 m width. Although the discharged air was disturbed as compared with Example 2, both the average droplet diameter and the uniformity of the coating film thickness were good. Setting conditions and evaluation results in Example 3 are shown in Table 1.
Conditions were the same as those in Example 2 except that the shape of the fluid holding surface was changed to a narrowing-end shape. Although the coating fluid discharged from some of the plurality of coating fluid discharge ports arranged in the width direction spread onto the fluid holding surface forming members, both the average droplet diameter and the uniformity of the coating film thickness showed good results. Setting conditions and evaluation results in Example 4 are shown in Table 1.
Conditions were the same as those in Example 2 except that the shape of the fluid holding surface was changed to a spreading-end shape. Although the coating fluid discharged from some of the plurality of coating fluid discharge ports arranged in the width direction could not be retained up to the nozzle tip and was transformed into coating fluid droplets, both the average droplet diameter and the uniformity of the coating film thickness showed good results. Setting conditions and evaluation results in Example 5 are shown in Table 1.
Evaluation was performed with H1 of 200 μm, L2 of 100 μm, the shape of the fluid holding surface of being orthogonal, and an air discharge flow rate of 1200 NL/min per 1 m width. Both the average droplet diameter and the uniformity of the coating film thickness showed good results. Setting conditions and evaluation results in Example 6 are shown in Table 1.
Conditions were the same as those in Example 1 except that H1 was modified to 0 μm. The average diameter of the coating fluid droplets was large, and granular unevenness was generated in the coating film due to the large average diameter, and thus the coating film uniformity was low. Setting conditions and evaluation results in Comparative Example 1 are shown in Table 1.
Conditions were same as those in Example 1 except that H1 was modified to 20 μm. As in Comparative Example 1, the average diameter of the coating fluid droplets was large, and granular unevenness was generated in the coating film due to the large average diameter, and thus the coating film uniformity was low. Setting conditions and evaluation results in Comparative Example 2 are shown in Table 1.
Conditions were the same as those in Example 1 except that H1 was modified to 150 μm. Since the discharged air collided with the fluid holding surface forming member, the flow of the discharged air was disturbed, and thus the coating film uniformity was low. Setting conditions and evaluation results in Comparative Example 3 are shown in Table 1.
Conditions were the same as those in Example 6 except that H1 was modified to 100 μm. The average diameter of the coating fluid droplets was large, and granular unevenness was generated in the coating film due to the large average diameter, and thus the coating film uniformity was low. Setting conditions and evaluation results in Comparative Example 4 are shown in Table 1.
Conditions were the same as those in Example 6 except that H1 was modified to 300 μm. Since the discharged air collided with the fluid holding surface forming member, the flow of the discharged air was disturbed, and thus the coating film uniformity was low. Setting conditions and evaluation results in Comparative Example 5 are shown in Table 1.
From the above Examples, it was confirmed that the coating fluid droplets were micronized and that the coating film uniformity was improved, and the effectiveness of the present invention was confirmed.
The present invention is effective as a slot-type spray nozzle, a coating device, and a manufacturing method of a film-coated member capable of forming fine coating fluid droplets even in a case where a discharged air flow rate is reduced and uniformly forming a thin coating film on a wide substrate.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2021-204235 | Dec 2021 | JP | national |
This application is the U.S. National Phase of PCT/JP2022/041239, filed Nov. 4, 2022, which claims priority to Japanese Patent Application No. 2021-204235, filed Dec. 16, 2021, the disclosures of these applications being incorporated herein by reference in their entireties for all purposes.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2022/041239 | 11/4/2022 | WO |
