Coating device, and method for manufacturing substrate with coating film

Abstract

A coating device of the present invention includes a coating fluid discharge nozzle including a plurality of coating fluid discharge ports arranged in a width direction of a substrate being conveyed, and at least two or more gas discharge nozzles for blowing gas to a plurality of columnar coating fluids discharged from the coating fluid discharge ports. These two gas discharge nozzles are provided with gas discharge ports between which a row of the coating fluid discharge ports is interposed as observed from a discharge direction of the coating fluid, the gas discharge ports being provided so as to be positioned at a location away from a virtual plane toward the substrate, the virtual plane passing through the coating fluid discharge ports and orthogonal to the discharge direction of the coating fluid, an axis extending in a discharge direction of the gas from each gas discharge port forming an angle of less than 90° with an axis extending in the discharge direction of the coating fluid from each coating fluid discharge port as observed from the width direction of the substrate.

Description

Field

[0001] The present invention relates to a coating device for applying coating fluid in the form of droplets onto substrates such as films, nonwoven fabrics, and paper, and a method for producing a coated substrate.Background

[0002] Conventionally, a spray coating device has been known as a coating device for coating a substrate with coating fluid in the form of droplets. In this spray coating device, from the viewpoint of productivity and functionality of the substrate, it is required to uniformly apply microdroplets to substantially the entire surface of the substrate having a wide width.

[0003] As the coating device in such a case, for example, Patent Literature 1 discloses a two-fluid slot-type spray nozzle (hereinafter, the "spray nozzle" is also simply referred to as a "nozzle") that is capable of spraying coating fluid by discharging compressed air simultaneously with the coating fluid, thereby atomizing the coating fluid with the discharged air. This spray nozzle has a plurality of coating fluid discharge ports in the width direction of the substrate, and air discharge ports are arranged so as to sandwich the coating fluid discharge ports from the upstream side and the downstream side in the substrate conveyance direction. Therefore, the discharged coating fluid in the form of droplets has a belt-like form continuous in the width direction of the substrate, so that variations in the coating film thickness and coating non-uniformity do not occur, and a uniform coating film can be formed.Citation ListPatent Literature

[0004] Patent Literature 1: Japanese Patent Application Laid-open No. 2006-026576SummaryTechnical Problem

[0005] However, in the slot-type spray nozzle disclosed in Patent Literature 1, since the air discharge ports are disposed in the vicinity of the coating fluid discharge ports, the discharged air promotes drying of the coating fluid at the coating fluid discharge ports. In this case, in a case where the coating fluid contains a solid content, the solid content is precipitated as the coating fluid is dried, and the coating fluid discharge ports may be clogged, or the opening areas may be reduced due to the precipitated solid content. In a case where the coating fluid discharge ports are clogged or the opening areas thereof are reduced, a streak-like coating missing continuous in the conveyance direction or regions having a small coating film thickness may be formed at the coating location corresponding to the relevant portion.

[0006] In addition, in the slot-type spray nozzle, since the coating fluid discharge ports and the air discharge ports are on substantially the same plane at the same height, the coating fluid at the coating fluid discharge port wet-spreads and reaches the air discharge port, and may be dried at the air discharge port. In this case, in a case where the coating fluid contains a solid content, the solid content is precipitated as the coating fluid is dried, and the air discharge port may be clogged or the opening area thereof may be reduced. In a case where the air discharge port is clogged or the opening area thereof is reduced, air necessary for forming droplets is not supplied even though the coating fluid is discharged at the relevant portion, and problems may thus occur in which the coating fluid is not sufficiently jetted, resulting in coating non-uniformity, or in which the non-jetted coating fluid accumulates in the vicinity of the coating fluid discharge port and subsequently falls onto the substrate to significantly deteriorate the coating appearance.

[0007] Furthermore, in a case where the coating fluid contains an organic solvent having a low boiling point or the like, the coating fluid is quickly dried, so that clogging of the coating fluid discharge port and the air discharge port due to precipitation of a solid content results in a more significant problem.

[0008] As described above, there has not been found a spray coating device that applies coating fluid while minimizing clogging of a coating fluid discharge port and an air discharge port due to drying of the coating fluid even in a case where coating fluid containing a solid content is applied in the coating device that applies the coating fluid in the form of droplets to a substrate such as a film, a nonwoven fabric, or paper.

[0009] Therefore, the present invention provides a spray coating device and a method for producing a coated substrate, which are capable of minimizing clogging of coating fluid discharge ports and air discharge ports due to drying of the coating fluid.Solution to Problem

[0010] [1] The present invention to solve the above-described problem is a coating device configured to apply coating fluid in a form of droplets onto a substrate being conveyed, the coating device including: a coating fluid discharge nozzle including a plurality of coating fluid discharge ports arranged in a width direction of a substrate; and at least two gas discharge nozzles for blowing gas to a plurality of columnar coating fluids discharged from the coating fluid discharge ports. The two gas discharge nozzles are provided with gas discharge ports between which a row of the coating fluid discharge ports is interposed as observed from a discharge direction of the coating fluid, the gas discharge ports being provided so as to be positioned at a location away from a virtual plane toward the substrate, the virtual plane passing through the coating fluid discharge ports and orthogonal to the discharge direction of the coating fluid, an axis extending in a discharge direction of the gas from each gas discharge port forming an angle of less than 90° with an axis extending in the discharge direction of the coating fluid from each coating fluid discharge port as observed from the width direction of the substrate. The coating device of the present invention preferably has the following embodiments [2] and [3]. [2] The coating device according to [1] above, wherein each gas discharge nozzle is provided to be able to change the discharge direction of the gas from each gas discharge port observed from the width direction of the substrate. [3] The coating device according to [1] or [2] above, wherein a distance from an intersection of the axis extending in the discharge direction of the coating fluid from each coating fluid discharge port and the axis extending in the discharge direction of the gas from each gas discharge port to each coating fluid discharge port as observed the coating device from the width direction of the substrate is 2 mm or more. [4] A method for producing a coated substrate of the present invention to solve the above-described problem includes: discharging coating fluid from a plurality of coating fluid discharge ports arranged in a width direction of a substrate toward the substrate being conveyed; blowing gas toward the coating fluid that is at a location away from the coating fluid discharge ports toward the substrate, as observed from the width direction of the substrate being conveyed, from a direction that is symmetric with respect to the coating fluid being discharged and from a direction in which an angle formed between the coating fluid being discharged and a discharge direction of the coating fluid is less than 90°; and applying the coating fluid formed into droplets onto the substrate. The method for producing a coated substrate according to the present invention preferably performs any one of the following [5] to [7]. [5] The method for producing a coated substrate according to [4] above, wherein a distance from the location at which the gas is blown onto the coating fluid to each coating fluid discharge port is 2 mm or more. [6] The method for producing a coated substrate according to [4] or [5] above, wherein the coating fluid contains a solid content. [7] The method for producing a coated substrate according to any one of [4] to [6] above, wherein a solvent of the coating fluid is an organic solvent. Advantageous Effects of Invention

[0011] It is possible, by using the coating device of the present invention, to minimize clogging of the coating fluid discharge port and the air discharge port due to drying of the coating fluid, and stably apply the coating fluid.Brief Description of Drawings

[0012] FIG. 1 is a schematic cross-sectional view of a coating device 100 of the present invention. FIG. 2 is an exploded perspective view illustrating a configuration of a coating fluid discharge nozzle 110 of FIG. 1. FIG. 3 is an exploded perspective view illustrating a configuration of a gas discharge nozzle 120 of FIG. 1. FIG. 4 is a schematic cross-sectional view of the coating device 100 of the present invention and a view illustrating a state during the formation of a coating film using the coating device 100. FIG. 5 is a bottom view of the tip end of the coating fluid discharge nozzle 110 of FIG. 1 as viewed from the coating fluid discharge port side. FIG. 6 is an exploded perspective view illustrating a configuration of a coating fluid discharge nozzle 210 according to another embodiment of the coating fluid discharge nozzle. FIG. 7 is a bottom view of the tip end of the gas discharge nozzle 120 of FIG. 1 as viewed from the gas discharge port side. FIG. 8 is an exploded perspective view illustrating a configuration of a gas discharge nozzle 220 according to another embodiment of the gas discharge nozzle. FIG. 9 is a schematic view illustrating a coated substrate manufacturing device 10 of the present invention. FIG. 10 is a schematic cross-sectional view of a conventional integrated two-fluid nozzle 300. Description of Embodiments

[0013] Desirable embodiments of the present invention will be described below with reference to the drawings. However, the present invention is not limited to the embodiments illustrated in the drawings, and various modifications can be made without departing from the gist of the invention, as long as the object of the invention can be achieved.

[0014] See FIG. 1. FIG. 1 is a schematic cross-sectional view of a coating device 100 according to a first embodiment of the present invention. The coating device 100 includes a coating fluid discharge nozzle 110 that discharges coating fluid, and gas discharge nozzles 120 and 120' that discharge gas.

[0015] See FIG. 2. FIG. 2 is an exploded perspective view illustrating a configuration of the coating fluid discharge nozzle 110 of FIG. 1. The coating fluid discharge nozzle 110 includes coating fluid nozzle blocks 111 and 112 and a coating fluid shim 113. One coating fluid nozzle block 111 has a coating fluid supply port 114 that supplies coating fluid into the coating fluid discharge nozzle 110, and a coating fluid manifold 115 for expanding the coating fluid in the width direction in communication with the coating fluid supply port 114. The coating fluid shim 113 is a comb shim interposed between the coating fluid nozzle blocks 111 and 112, and gaps between comb teeth of the coating fluid shim 113 form a plurality of coating fluid channels in the width direction by combining with the coating fluid nozzle blocks 111 and 112. The gaps between the comb teeth of the coating fluid shim 113 communicate with the coating fluid manifold 115.

[0016] Note that the "width direction" corresponds to a direction orthogonal to a discharging direction X of the coating fluid and a conveyance direction Y (see FIG. 1) of a substrate 1.

[0017] See FIG. 3. FIG. 3 is an exploded perspective view illustrating the configuration of the gas discharge nozzle 120 of FIG. 1, and the gas discharge nozzle 120' of FIG. 1 has the same configuration. The gas discharge nozzle 120 includes gas nozzle blocks 121 and 122 and a gas shim 123. One gas nozzle block 121 has a gas supply port 124 that supplies gas into the gas discharge nozzle 120, and a gas manifold 125 for expanding the gas in the width direction in communication with the gas supply port 124. The gas shim 123 is a shim having a U-shape, and forms a slit-shaped gas channel in the width direction by being interposed between the gas nozzle blocks 121 and 122. In this case, the gas channel of the gas shim 123 communicates with the gas manifold 125.

[0018] See FIG. 1 again. The coating fluid is discharged from coating fluid discharge ports 116 that are located at the tip end of the coating fluid discharge nozzle 110 and arranged in a line in the width direction. The gas is discharged from the gas discharge ports 126 and 126' located at the tip ends of the gas discharge nozzles 120 and 120'. The gas discharge nozzles 120 and 120' are provided such that the gas discharge ports 126 and 126' are arranged, with a row of the coating fluid discharge ports 116 of the coating fluid discharge nozzle 110 interposed therebetween as observed from the discharge direction X of the coating fluid, and the gas discharge ports 126 and 126' are away from a virtual plane A toward the discharge direction X of the coating fluid, the virtual plane A passing through the coating fluid discharge ports 116 and orthogonal to the discharge direction X. In this case, the gas discharge ports 126 and 126' are located on the substrate 1 side with respect to the virtual plane A. Here, the coating device 100 is installed at a predetermined distance from the substrate 1, and the coating fluid discharge ports 116 of the coating fluid discharge nozzle 110 are arranged such that an extension line of the discharge direction X of the coating fluid intersects the substrate 1. The coating fluid discharge nozzle 110 and the gas discharge nozzles 120 and 120' extend in a direction orthogonal to the conveyance direction Y of the substrate 1, that is, in the width direction of the substrate 1.

[0019] See FIG. 4. FIG. 4 is a schematic cross-sectional view of the coating device 100 of the present invention and illustrates a state in which coating fluid is applied to a substrate using the coating device 100. First, the coating fluid 2 supplied to the coating fluid discharge nozzle 110 is discharged from a plurality of coating fluid discharge ports 116 provided at the tip end of the coating fluid discharge nozzle 110, and the discharged coating fluid continuously forms a columnar coating fluid 3. Next, the columnar coating fluid 3 collides with the gas discharged from the gas discharge ports 126 and 126' provided at the tip ends of the gas discharge nozzles 120 and 120' at a collision point B, and is converted into fine droplets 4. The collision point B is an intersection between an axis extending in the discharge direction X of the coating fluid from the coating fluid discharge ports 116 and an axis extending in the discharge direction of the gas from the gas discharge ports 126 and 126'. The fine droplets 4 land on the substrate 1 being conveyed and form a coating film 5. Here, since the gas discharge ports 126 and 126' are located away from the virtual plane A in the discharge direction X of the coating fluid, the gas discharged from the gas discharge ports 126 and 126' does not attenuate by hitting the coating fluid discharge nozzle 110, and furthermore, the discharged gas does not directly hit the coating fluid discharge ports 116. That is, drying of the coating fluid at the coating fluid discharge ports 116 can be suppressed. In this case, since the gas discharged from the gas discharge ports 126 and 126' diffuses as it moves away from the gas discharge ports 126 and 126', it is preferable that a distance L1 between the coating fluid discharge ports 116 and the collision point B is 2 mm or more so that the gas is not directly blown onto the coating fluid discharge ports 116. Since the coating fluid discharge nozzle 110 having the coating fluid discharge ports 116 and the gas discharge nozzles 120 and 120' having the gas discharge ports 126 and 126' are independently arranged from each other, even though the coating fluid spreads from the coating fluid discharge ports 116, the coating fluid does not reach the gas discharge ports 126 and 126', and the coating fluid does not dry at the gas discharge ports 126 and 126'.

[0020] It is also preferable that distances L2 and L2' between the gas discharge ports 126 and 126' and the collision point B are 2 mm or more in order to prevent the columnar coating fluid 3 discharged from the coating fluid discharge nozzle 110 from adhering to the gas discharge ports 126 and 126'. In addition, in order to convert the columnar coating fluid 3 into the fine droplets 4, it is necessary to discharge gas at high speed from the gas discharge nozzles 120 and 120' and cause the gas to collide with the columnar coating fluid 3 at the collision point B. Therefore, in order to obtain the fine droplets 4, it is more preferable that the distances L2 and L2' are 10 mm or less.

[0021] Note that, in order to discharge the coating fluid 2 in a columnar shape from the coating fluid discharge ports 116, it is necessary to forcefully discharge the coating fluid 2 from each of the coating fluid discharge ports 116, and the discharge amount may be appropriately adjusted according to the type and viscosity of the coating fluid 2. As a result of intensive studies by the inventor, the average flow rate of the coating fluid 2 in the comb-shaped coating fluid channel inside the coating fluid discharge nozzle 110 is preferably 2 m / s or more, and more preferably 5 m / s or more in order to stabilize the shape of the columnar coating fluid 3 after discharge regardless of the type and viscosity of the coating fluid 2.

[0022] On the other hand, in order to form the columnar coating fluid 3 into the fine droplets 4, it is necessary to vigorously discharge gas from the gas discharge ports 126 and 126'. As a result of intensive studies by the inventor, the average flow velocity of the gas in the slit-shaped gas channel inside the gas discharge nozzles 120 and 120' is preferably 100 m / s or more. Furthermore, assuming a case where the shape of the columnar coating fluid 3 is not stable, such as immediately after the start of discharge of the coating fluid, the gas discharge nozzles 120 and 120' may have a retraction mechanism.

[0023] The gas discharge nozzles 120 and 120' are installed such that the discharge direction of the gas can be optionally changed, and angles θ and θ' (hereinafter referred to as a "collision angles θ and θ'") formed between the discharge direction X of the coating fluid discharged from the coating fluid discharge ports 116 and each axis extending in the discharge direction of the gas from the gas discharge ports 126 and 126' can be optionally changed. In order to cause the droplets 4 atomized at the collision point B to fly toward the substrate 1 and land thereon, it is necessary that each of the collision angles θ and θ' are less than 90°. In addition, since the collision angles θ and θ' affect the size of the droplets deposited on the substrate 1, the collision angles θ and θ' may be appropriately changed, the size of the droplets can be reduced by increasing the collision angles θ and θ', and the size of the droplets can be increased by decreasing the collision angles θ and θ'.

[0024] In addition, the gas discharge nozzles 120 and 120' do not need to be installed symmetrically with respect to the discharge direction X of the coating fluid discharged from the coating fluid discharge ports 116, and may be installed asymmetrically with respect to the coating fluid discharge nozzle 110. That is, the gas discharged from the gas discharge nozzles 120 and 120' may respectively collide with the columnar coating fluid 3 at the collision points B and B', and the distances L2 and L2' and the collision angles θ and θ' can be optionally changed.

[0025] See FIG. 5. FIG. 5 is a bottom view of the coating fluid discharge nozzle 110 when the tip end of the coating fluid discharge nozzle 110 of FIG. 1 is viewed from the coating fluid discharge port side. The coating fluid discharge ports 116 of the coating fluid discharge nozzle 110 are rectangular opening portions and are arranged at a predetermined interval W1 (hereinafter referred to as the "arrangement pitch") in the longitudinal direction of the coating fluid discharge nozzle 110, and the total of all the coating fluid discharge ports 116 defines a coating fluid discharge width W2. In this case, the width of the coating film that can be formed on the substrate 1 is substantially the same as the coating fluid discharge width W2. It is preferable that an opening width W3 of each coating fluid discharge port 116 is 50 µm or more so that the rate of change in the opening area remains small even though a manufacturing variation of about 5 µm occurs between discharge ports, and it is preferable that a thickness t1 of the coating fluid shim 113 is 50 µm or more so that the rate of change in the opening area is reduced even though a thickness variation of about 5 µm occurs in the shim. In addition, the opening area of each of the coating fluid discharge ports 116 may be appropriately adjusted depending on the viscosity of the coating fluid to be used and the flow rate of the coating fluid to be discharged, and, in order to cause the coating fluid discharged from the coating fluid discharge ports 116 to have a constant flow rate and discharge the coating fluid in a columnar shape, it is preferable to set the opening area to 50,000 µm 2< or less so that the average flow rate does not decrease, and it is more preferable to set the opening area to 20,000 µm 2< or less. The arrangement pitch W1 of the coating fluid discharge ports is preferably 10 mm or less from the viewpoint of coating film uniformity. Furthermore, the coating fluid discharge width W2 is preferably smaller than the substrate width in order to minimize scattering of the coating fluid to the outside of the system.

[0026] See FIG. 6. FIG. 6 is an exploded perspective view illustrating a configuration of a coating fluid discharge nozzle 210 according to another embodiment of the coating fluid discharge nozzle. The coating fluid discharge nozzle 210 includes coating fluid nozzle blocks 211 and 212. One coating fluid nozzle block 211 has a coating fluid supply port 214 that supplies coating fluid into the coating fluid discharge nozzle 210. The other coating fluid nozzle block 212 has a coating fluid manifold 215 for expanding the coating fluid in the width direction and a coating fluid discharge channel 217 communicating with the coating fluid manifold 215, and a coating fluid discharge port 216 is formed at the tip end of the coating fluid discharge channel 217. The shape of the coating fluid discharge port 216 is not limited to a rectangle, and may be a circle or an ellipse.

[0027] See FIG. 7. FIG. 7 is a bottom view of the gas discharge nozzle 120 when the tip end of the gas discharge nozzle 120 of FIG. 1 is viewed from the gas discharge port side. The gas discharge port 126 of the gas discharge nozzle 120 has a slit shape, and the width of the gas discharge port 126 is a gas discharge width W4. Here, two-dot chain lines indicated by reference numerals 116L and 116R indicate locations of both ends of the coating fluid discharge width W2 in the coating fluid discharge nozzle 110. The gas discharge width W4 is longer than the coating fluid discharge width W2 in order to form all the columnar coating fluids 3 discharged from the respective coating fluid discharge ports 116 into the fine droplets 4. The shape of the gas discharge port 126 is not limited to one slit continuous in the width direction as illustrated in FIGS. 3 and 7, and may be intermittently opened in the width direction so as to correspond to the coating fluid discharge ports 116 on a one-to-one basis. In a case of opening intermittently, the opening length in the width direction is preferably larger than the width W3 of each of the coating fluid discharge ports 116.

[0028] See FIG. 8. FIG. 8 is an exploded perspective view illustrating a configuration of a gas discharge nozzle 220 according to another embodiment of the gas discharge nozzle. The gas discharge nozzle 220 includes gas nozzle blocks 221 and 222. One gas nozzle block 221 has a gas supply port 224 that supplies gas into the gas discharge nozzle 220. The other gas nozzle block 222 has a gas manifold 225 for expanding the gas in the width direction and a gas discharge channel 227 communicating with the gas manifold 225, and a gas discharge port 226 is formed at the tip end of the gas discharge channel 227. The shape of the gas discharge port 226 is not limited to a rectangle, and may be a circle or an ellipse.

[0029] As described above, by using the spray coating device according to the present invention, even when coating fluid containing a solid content is discharged, the coating fluid can be stably applied without clogging the coating fluid discharge ports or the gas discharge ports.

[0030] Next, a coated substrate manufacturing device 10 for manufacturing a coated substrate using the coating device 100 of the present invention will be described with reference to FIG. 9. FIG. 9 is a schematic view illustrating an example of a coated substrate manufacturing device 10 of the present invention.

[0031] The coated substrate manufacturing device 10 includes an unwinding unit 11 that unwinds the substrate 1 and a winding unit 12 that winds a coated substrate 6. The coating device 100 that applies coating fluid to the substrate 1 and a drying device 13 that dries a coating film are provided between the unwinding unit 11 and the winding unit 12. In addition, in order to suppress changes of the distance between the coating device 100 and the substrate 1 over time, which are caused by vibration of the substrate 1 due to the gas discharged from the coating device 100, a backup roll 14 is provided on the opposite side of the coating device 100 across the substrate 1, and is in contact with the substrate 1 to support the substrate 1. In this case, by having the substrate 1 trained around the backup roll 14, the backup roll 14 rotates as the substrate 1 is conveyed and it is also possible to prevent the substrate 1 from sliding on the backup roll 14 and being damaged. Furthermore, as a coating fluid discharge mechanism, the coated substrate manufacturing device 10 is provided with a liquid feeding pump 15 that supplies the coating fluid to the coating device 100 and a tank 16 that stores the coating fluid, and as a gas discharge mechanism, the coated substrate manufacturing device 10 is provided with a pressurized gas source 17 for supplying gas to the coating device 100, a branch pipe 18 for branching the gas to each gas discharge nozzle, and pressure regulating valves 19 and 19' that individually adjust the pressure of the gas supplied from each gas discharge nozzle. The coating device 100 and the backup roll 14 are enclosed by a booth 20, and a bottom portion of the booth 20 has an opening portion 21 that is in communication with a waste liquid collection tank 22.

[0032] The booth 20 prevents some droplets scattered without adhering to the substrate 1, among the fine droplets 4 discharged and formed from the coating device 100, from scattering to the surroundings. The coating fluid adhering to the inner wall of the booth 20 drips down along the inner wall of the booth 20, and is collected in the waste liquid collection tank 22 through the bottom opening portion 21. Since the booth 20 and the waste liquid collection tank 22 are in contact with the coating fluid, it is preferable to select a material according to the coating fluid, and for example, in a case where the solvent of the coating fluid is acetone that is a low-boiling point organic solvent, it is preferable to use a metal or a resin material having excellent acetone resistance, for example, a fluororesin.

[0033] In the coated substrate manufacturing device 10 illustrated in FIG. 9, the coating fluid discharge direction from the coating device 100 is the vertically downward direction, and the conveyance direction of the substrate 1 of the portion is the horizontal direction; however, the present invention is not limited thereto as long as the coating device 100 is installed so as to substantially face a coating surface of the substrate 1, and for example, the coating fluid discharge direction from the coating device 100 may be the horizontal direction, and the conveyance direction of the portion may be the vertical direction.

[0034] Next, a method for producing a coated substrate using the coating device 100 of the present invention will be described again with reference to FIG. 4. The coated substrate is produced by forming the coating film 5 on the substrate 1 by the coating device 100. In this case, since the basis weight of the coating film 5 can be controlled by the flow rate of the coating fluid 2 supplied to the coating fluid discharge nozzle 110, it is preferable to have a means for measuring the basis weight of the formed coating film 5 to adjust the supply flow rate of the coating fluid 2. The size of the attached droplets is determined by the flow rate and the collision angles θ and θ' of the gas supplied to the gas discharge nozzles 120 and 120'. In order to reduce the size of the droplets, the flow rate of the gas supplied to the gas discharge nozzles 120 and 120' is increased, or the collision angles θ and θ' are increased. On the other hand, in a case where it is desired to increase the size of the droplets, the size of the droplets can be adjusted by decreasing the flow rate of the gas supplied to the gas discharge nozzles 120 and 120' or decreasing the collision angles θ and θ'.

[0035] In addition, immediately after the start of discharging the coating fluid, the discharge pressure of the coating fluid 2 from the coating fluid discharge ports 116 of the coating fluid discharge nozzle 110 is low, and until the pressure rises to a predetermined discharge pressure, the shape of the columnar coating fluid 3 may not be stable. Therefore, it is preferable to retract the gas supply nozzles 120 and 120' in advance so that the coating fluid does not scatter to the gas supply nozzles 120 and 120' until a stable columnar coating fluid 3 is formed. Thereafter, after the shape of the columnar coating fluid 3 is stabilized, the gas discharge nozzles 120 and 120' are brought close to the columnar coating fluid 3, and the gas is discharged from the gas discharge ports 126 and 126'. As a result, since the coating fluid 2 does not adhere to the gas discharge ports 126 and 126', stable coating can be performed without clogging of the gas discharge ports 126 and 126'.

[0036] The coating device of the present invention can obtain a large effect particularly on coating fluid containing a solid content, such as a solution of an inorganic substance or an organic substance or a dispersion of an inorganic substance or an organic substance dispersed in a solvent. The viscosity of the coating fluid may be any viscosity as long as the coating fluid can be refined by collision of the discharged gas, and as the viscosity is lower, fine droplets can be formed. In general, when the viscosity is 500 mPa·s or less, a good coating appearance can be obtained. In particular, the viscosity is preferably 2.0 mPa·s or less.

[0037] In addition, in a case where an organic solvent is contained in a part of the solvent of the coating fluid, the effect of the present invention can be particularly obtained. In particular, it is possible to obtain a significant effect on coating fluid containing at least one of acetaldehyde, acetone, acetonitrile, allyl alcohol, benzene, 2-butanol, methyl ethyl ketone, tert-butyl alcohol, carbon disulfide, chloroform, cyclohexane, 1,2-dichloroethane, dichloromethane, diethyl ether, ethanol, anhydrous ethanol, ethyl acetate, 1,2-dimethoxyethane, ethyl formate, ethyl propionate, heptane, hexane, ligroin, methanol, methyl acetate, methyl propionate, pentane, petroleum benzine, 1-propanol, propylene oxide, n-propyl ether, tetrahydrofuran, trichloroethylene, triethylamine, and trifluoroacetic acid, which are low-boiling organic solvents having a boiling point of 100°C or lower.

[0038] The type of gas or atmospheric gas component used in the present invention is not particularly limited as long as it is suitable for coating, and air, nitrogen gas, and the like can be used. The ambient pressure of the external atmosphere is not particularly limited, and may be set to an atmospheric pressure environment or a reduced-pressure environment. In addition, the temperature of the gas or the outside air is not particularly limited, but drying of the fine droplets flying is promoted by using hot air as the gas. As a result, finer droplets can be formed, and the amount of moisture attached to the substrate is reduced, so that the drying load in the subsequent step can also be reduced.[Examples]

[0039] Hereinafter, the present invention will be described in more detail with reference to Examples. Note that the present invention is not limited to the following Examples.<Coating fluid>

[0040] As a solid content, polyvinylidene fluoride, which is a fluororesin, was prepared, and as a solvent, acetone (boiling point: 56°C), which is a low-boiling organic solvent, was prepared to produce coating fluid by mixing them to have a solid content concentration of 5% by weight.[Example 1]

[0041] The coating device 100 of FIG. 1 was mounted in the coated substrate manufacturing device 10 of FIG. 9 to produce a coated substrate 6. A coating film was formed on the substrate 1 unwound from the unwinding unit 11 using the coating device 100, the coating film was completely dried by the drying device 13, and the coated substrate 6 was then wound up by the winding unit 12. Thereafter, the coated substrate 6 that had been wound was taken out, and the presence or absence of droplet adhesion and the coating appearance were evaluated by visual observation and microscopic examination. As coating conditions in the coating device 100, the distance from the virtual plane A passing through the coating fluid discharge ports 116 to the gas discharge ports 126 and 126' was set to 7.5 mm, the distance L1 between the coating fluid discharge ports 116 and the collision point B was set to 10 mm, the distances L2 and L2' between the gas discharge ports 126 and 126' and the collision point B were set to 5 mm, and the collision angles θ and θ' were set to 60° (see FIG. 4). The coating fluid discharge nozzle 110 had a coating fluid discharge width W2 of 210.1 mm, an opening width W3 of the coating fluid discharge port of 100 µm, a thickness t1 of the coating fluid shim of 100 µm, and an arrangement pitch W1 of the coating fluid discharge ports of 7.5 mm. In this case, the number of coating fluid discharge ports 116 is 29 (see FIG. 5). In the gas discharge nozzles 120 and 120', the gas discharge width W4 was 250 mm, and the thickness of the gas shim was 50 µm (see FIG. 7). As a coating procedure, the substrate 1 was conveyed at a speed of 50 m / min, the coating fluid was discharged from the coating fluid discharge nozzle 110 at 100 mL / min, and compressed air was discharged from each of the gas discharge nozzles 120 and 120' at 300 L / min.[Example 2]

[0042] The substrate 1 was coated under the same conditions as those in Example 1 except that the collision angles θ and θ' were 30°.[Example 3]

[0043] The substrate 1 was coated under the same conditions as those in Example 1 except that the distance L1 between the coating fluid discharge ports 116 and the collision point B was 2 mm and the collision angles θ and θ' were 80°.[Comparative Example 1]

[0044] The substrate 1 was coated under the same conditions as those in Example 1 except that the distance L1 between the coating fluid discharge ports 116 and the collision point B was 0.5 mm. In Comparative Example 1, in relation to the distance L1, the gas discharge ports 126 and 126' are located on the opposite side to the substrate 1 side with respect the virtual plane A. That is, the gas discharge ports 126 and 126' according to Comparative Example 1 are located on the coating fluid discharge nozzle 110 side with respect the virtual plane A.[Comparative Example 2]

[0045] The substrate 1 was coated under the same conditions as those in Example 1 except that the collision angles θ and θ' were 90°.[Comparative Example 3]

[0046] The substrate 1 was coated using a conventional integrated two-fluid nozzle 300 illustrated in FIG. 10. The integrated two-fluid nozzle 300 has a longitudinal direction in a direction orthogonal to the conveyance direction Y of the substrate 1, that is, a width direction of the substrate 1 (direction orthogonal to the paper surface), and is installed so as to face the substrate 1 with a certain distance from the substrate 1. The integrated two-fluid nozzle 300 is formed of outer die blocks 301 and 301' and inner die blocks 302 and 302'. The coating fluid is supplied to a coating fluid pocket 303 and discharged from a coating fluid discharge port 304, and the gas is supplied to gas pockets 305 and 305' and discharged from gas discharge ports 306 and 306'. The gas discharge ports 306 and 306' are provided between which the coating fluid discharge port 304 is interposed as observed from the discharge direction of the coating fluid. The coating fluid discharge port 304 and the gas discharge ports 306 and 306' are on the same plane. The substrate 1 was coated in the same procedure as in Example 1 using this integrated two-fluid nozzle 300.<Evaluation Method>

[0047] In the above-described Examples and Comparative Examples, the coating was continuously performed for 30 minutes. The coated state was evaluated using the coated substrate 6 wound by the winding unit 12. The evaluation results are illustrated in Tables 1 and 2. For the droplet attachability in the tables, the adhesion rate of droplets to the substrate was used as a criterion. The adhesion rate of the droplets to the substrate was determined by measuring the basis weight of each of the coated substrate and the substrate before coating to calculate the basis weight of the coating film formed on the substrate, and calculating the ratio of the basis weight to the total solid content contained in the coating fluid supplied to the coating fluid discharge nozzle. As the evaluation on whether droplets could be attached or not, it was determined as "∘" when the total solid content was 30% or more and "×" when the total solid content was less than 30%. In addition, the average particle diameter of the droplets was measured using a laser diffraction particle distribution meter (FLD-319A manufactured by Seika Digital Image Co., Ltd.) for the flying droplets immediately before being attached to the substrate. Note that, incidentally, the average particle diameter illustrated here refers to a Sauter average diameter. In addition, in order to confirm the clogging situation of the coating fluid discharge ports 116 during the coating operation, a pressure gauge (not illustrated) was installed so as to communicate with the coating fluid manifold 115, and the pressure in the coating fluid manifold was measured 15 minutes and 30 minutes after the start of coating. In the coating appearance, the coating missing represents a coating missing region where application is not performed in a streak shape generated in the substrate conveyance direction, and the coating non-uniformity is linear appearance non-uniformity generated in the substrate conveyance direction, and represents coating non-uniformity caused by a difference in the ratio of fluid deposition on the substrate. In addition, for the evaluation of the clogging of the coating fluid discharge ports and the clogging of the gas discharge port, the tip end of each discharge nozzle was observed after continuous coating for 30 minutes, and it was determined that the clogging was present in a case where the clogging was observed even partially. Immediately after the start of coating, the appearance of the coating film was good in all Examples and Comparative Examples, and the pressure in the coating fluid manifold was 0.1 MPa. Table 1Example 1Example 2Example 3Distance L1 between coating fluid discharge port and collision point [mm]10102Distances L2 and L2' between gas discharge port and collision point [mm]555Collision angles θ and θ' [°]603080Droplet attachability○○○○: Droplets are attached (adhesion rate of 30% or more)×: Droplets are not attached (adhesion rate of less than 30%)Average particle diameter of droplets [µm]408030Pressure inside coating fluid manifold (after 15 minutes) [MPa]0.10.10.1Pressure inside coating fluid manifold (after 30 minutes) [MPa]0.10.10.1Coating appearance○○○○: Good×: PoorClogging of coating fluid discharge portAbsence of cloggingAbsence of cloggingAbsence of cloggingClogging of gas discharge portAbsence of cloggingAbsence of cloggingAbsence of clogging Table 2 Comparative Example 1Comparative Example 2Comparative Example 3Distance L1 between coating fluid discharge port and collision point [mm]0.5100.8Distances L2 and L2' between gas discharge port and collision point [mm]551Collision angles θ and θ' [°]609030Droplet attachability××○○: Droplets are attached (adhesion rate of 30% or more)×: Droplets are not attached (adhesion rate of less than 30%)Average particle diameter of droplets [µm]--20Pressure inside coating fluid manifold (after 15 minutes) [MPa]0.10.20.2Pressure inside coating fluid manifold (after 30 minutes) [MPa]0.10.30.4Coating appearance--×○: GoodCoating missing×: PoorCoating non-uniformityClogging of coating fluid discharge portAbsence of cloggingPresence of cloggingPresence of cloggingClogging of gas discharge portAbsence of cloggingAbsence of cloggingPresence of clogging [Comparison between Example 1 and Comparative Example 3]

[0048] In the conventional integrated two-fluid nozzle 300 described in Comparative Example 3, the solid content of the coating fluid was precipitated at both the coating fluid discharge port 304 and the gas discharge ports 306 and 306' after 30 minutes from the start of coating, and the clogging was confirmed at each discharge port. In addition, due to this, a streak-like coating missing region and linear application unevenness were observed on the substrate after coating. Furthermore, the pressure of the coating fluid manifold increased to 0.2 MPa when 15 minutes had elapsed from the start of coating. When the coating fluid discharge port is clogged, the opening area of the coating fluid discharge port is reduced. Therefore, when a fixed amount of the coating fluid is continuously fed by the liquid feeding pump, the pressure inside the coating fluid manifold increases. That is, it was confirmed that a part of the coating fluid discharge port 304 was clogged in a short time until 15 minutes elapsed from the start of coating. On the other hand, in Example 1, the pressure inside the coating fluid manifold did not increase even 30 minutes after the start of coating, the coating fluid discharge ports 116 and the gas discharge ports 126 and 126' were not clogged, and the coating film 5 having a good coating appearance could be formed.[Comparison between Example 1 and Example 2]

[0049] In Example 2, it was confirmed that by reducing the collision angles θ and θ', the average particle diameter of droplets was increased as compared with Example 1. That is, it was confirmed that the force of colliding with the columnar coating fluid 3 can be controlled by changing the collision angles θ and θ', and the average particle diameter of the droplets can be changed to a desired size. In addition, in both of Examples 1 and 2, the pressure inside the coating fluid manifold did not increase even after a lapse of 30 minutes from the start of coating, the coating fluid discharge ports 116 and the gas discharge ports 126 and 126' were not clogged, and the coating film 5 having a good coating appearance could be formed.[Comparison between Example 1 and Example 3]

[0050] In Example 3, the distance L1 between the coating fluid discharge port and the collision point was set to 2 mm, and the collision angles θ and 0' were set to 80° so that the gas discharge ports 126 and 126' were located away from the virtual plane A toward the substrate 1 side. It was confirmed that the average particle diameter of the droplets was reduced by increasing the collision angles θ and θ' as compared with Example 1. In addition, in both of Examples 1 and 3, the pressure inside the coating fluid manifold did not increase even after a lapse of 30 minutes from the start of coating, the coating fluid discharge ports 116 and the gas discharge ports 126 and 126' were not clogged, and the coating film 5 having a good coating appearance could be formed.[Comparison between Example 1 and Comparative Example 1]

[0051] In Comparative Example 1, the gas discharge ports 126 and 126' are located on the side opposite to the substrate 1 side with respect to the virtual plane A. The gas discharged from the gas discharge ports 126 and 126' did not hit the columnar coating fluid 3 by hitting the coating fluid discharge nozzle 110, and the atomized droplets 4 were not formed. Thereafter, in order to apply the gas discharged from the gas discharge ports 126 and 126' to the columnar coating fluid 3, the collision angles θ and θ' were adjusted while the locations of the gas discharge ports 126 and 126' were fixed, but in the range of L2 ≤ 10 mm, the atomized droplets 4 could not be formed, and in the range of L2 > 10 mm, the gas colliding with the columnar coating fluid 3 was attenuated, and the fine droplets 4 could not be formed.[Comparison between Example 1 and Comparative Example 2]

[0052] In Comparative Example 2, the collision angles θ and θ' are 90°. Therefore, the atomized droplets 4 micronized at the collision point B did not move toward the substrate 1, and as a result, the droplet adhesion rate was significantly reduced to 10%. Further, a part of the fine droplets 4 directed to the coating fluid discharge ports 116 was precipitated at the coating fluid discharge ports 116, and a part of the coating fluid discharge ports 116 was clogged.Industrial Applicability

[0053] The present invention can be applied to the coating device for forming a coating film on the substrate film of a resin, paper, a metal thin film, cloth, or the like, and a coated substrate producing device including the coating device and a coated substrate producing method, but is not limited thereto.Reference Signs List

[0054] 1 Substrate 2 Coating fluid 3 Columnar coating fluid 4 Fine droplet 5 Coating film 6 Coated substrate 10 Coated substrate manufacturing device 11 Unwinding unit 12 Winding unit 13 Drying device 14 Backup roll 15 Liquid feeding pump 16 Tank 17 Pressurized gas source 18 Branch pipe 19, 19' Pressure regulating valve 20 Booth 21 Bottom opening portion 22 Waste liquid collection tank 100 Coating device 110 Coating fluid discharge nozzle 111, 112 Coating fluid nozzle block 113 Coating fluid shim 114 Coating fluid supply port 115 Coating fluid manifold 116 Coating fluid discharge port 120, 120' Gas discharge nozzle 121, 122 Gas nozzle block 123 Gas shim 124 Gas supply port 125, 125' Gas manifold 126, 126' Gas discharge port 210 Coating fluid discharge nozzle 211, 212 Coating fluid nozzle block 214 Coating fluid supply port 215 Coating fluid manifold 216 Coating fluid discharge port 217 Coating fluid discharge channel 220 Gas discharge nozzle 221, 222 Gas nozzle block 224 Gas supply port 225 Gas manifold 226 Gas discharge port 227 Gas discharge channel 300 Integrated two-fluid nozzle 301, 301' Outer die block 302, 302' Inner die block 303 Coating fluid pocket 304 Coating fluid discharge port 305, 305' Gas pocket 306, 306' Gas discharge port A Virtual plane B, B' Collision point L1 Distance between coating fluid discharge port and collision point L2, L2' Distance between gas discharge port and collision point t1 Thickness of coating fluid shim W1 Arrangement pitch of coating fluid discharge ports W2 Coating fluid discharge width W3 Opening width of each coating fluid discharge port W4 Gas discharge width X Discharge direction of coating fluid Y Conveyance direction of substrate θ, θ' Collision angle

Examples

example 1

[Example 1]

[0041]The coating device 100 of FIG. 1 was mounted in the coated substrate manufacturing device 10 of FIG. 9 to produce a coated substrate 6. A coating film was formed on the substrate 1 unwound from the unwinding unit 11 using the coating device 100, the coating film was completely dried by the drying device 13, and the coated substrate 6 was then wound up by the winding unit 12. Thereafter, the coated substrate 6 that had been wound was taken out, and the presence or absence of droplet adhesion and the coating appearance were evaluated by visual observation and microscopic examination. As coating conditions in the coating device 100, the distance from the virtual plane A passing through the coating fluid discharge ports 116 to the gas discharge ports 126 and 126' was set to 7.5 mm, the distance L1 between the coating fluid discharge ports 116 and the collision point B was set to 10 mm, the distances L2 and L2' between the gas discharge ports 126 and 126' and the collisi...

example 2

[Example 2]

[0042]The substrate 1 was coated under the same conditions as those in Example 1 except that the collision angles θ and θ' were 30°.

example 3

[Example 3]

[0043]The substrate 1 was coated under the same conditions as those in Example 1 except that the distance L1 between the coating fluid discharge ports 116 and the collision point B was 2 mm and the collision angles θ and θ' were 80°.

Field

[0001] The present invention relates to a coating device for applying coating fluid in the form of droplets onto substrates such as films, nonwoven fabrics, and paper, and a method for producing a coated substrate.Background

[0002] Conventionally, a spray coating device has been known as a coating device for coating a substrate with coating fluid in the form of droplets. In this spray coating device, from the viewpoint of productivity and functionality of the substrate, it is required to uniformly apply microdroplets to substantially the entire surface of the substrate having a wide width.

[0003] As the coating device in such a case, for example, Patent Literature 1 discloses a two-fluid slot-type spray nozzle (hereinafter, the "spray nozzle" is also simply referred to as a "nozzle") that is capable of spraying coating fluid by discharging compressed air simultaneously with the coating fluid, thereby atomizing the coating fluid with the discharged air. This spray nozzle has a plurality of coating fluid discharge ports in the width direction of the substrate, and air discharge ports are arranged so as to sandwich the coating fluid discharge ports from the upstream side and the downstream side in the substrate conveyance direction. Therefore, the discharged coating fluid in the form of droplets has a belt-like form continuous in the width direction of the substrate, so that variations in the coating film thickness and coating non-uniformity do not occur, and a uniform coating film can be formed.Citation ListPatent Literature

[0004] Patent Literature 1: Japanese Patent Application Laid-open No. 2006-026576SummaryTechnical Problem

[0005] However, in the slot-type spray nozzle disclosed in Patent Literature 1, since the air discharge ports are disposed in the vicinity of the coating fluid discharge ports, the discharged air promotes drying of the coating fluid at the coating fluid discharge ports. In this case, in a case where the coating fluid contains a solid content, the solid content is precipitated as the coating fluid is dried, and the coating fluid discharge ports may be clogged, or the opening areas may be reduced due to the precipitated solid content. In a case where the coating fluid discharge ports are clogged or the opening areas thereof are reduced, a streak-like coating missing continuous in the conveyance direction or regions having a small coating film thickness may be formed at the coating location corresponding to the relevant portion.

[0006] In addition, in the slot-type spray nozzle, since the coating fluid discharge ports and the air discharge ports are on substantially the same plane at the same height, the coating fluid at the coating fluid discharge port wet-spreads and reaches the air discharge port, and may be dried at the air discharge port. In this case, in a case where the coating fluid contains a solid content, the solid content is precipitated as the coating fluid is dried, and the air discharge port may be clogged or the opening area thereof may be reduced. In a case where the air discharge port is clogged or the opening area thereof is reduced, air necessary for forming droplets is not supplied even though the coating fluid is discharged at the relevant portion, and problems may thus occur in which the coating fluid is not sufficiently jetted, resulting in coating non-uniformity, or in which the non-jetted coating fluid accumulates in the vicinity of the coating fluid discharge port and subsequently falls onto the substrate to significantly deteriorate the coating appearance.

[0007] Furthermore, in a case where the coating fluid contains an organic solvent having a low boiling point or the like, the coating fluid is quickly dried, so that clogging of the coating fluid discharge port and the air discharge port due to precipitation of a solid content results in a more significant problem.

[0008] As described above, there has not been found a spray coating device that applies coating fluid while minimizing clogging of a coating fluid discharge port and an air discharge port due to drying of the coating fluid even in a case where coating fluid containing a solid content is applied in the coating device that applies the coating fluid in the form of droplets to a substrate such as a film, a nonwoven fabric, or paper.

[0009] Therefore, the present invention provides a spray coating device and a method for producing a coated substrate, which are capable of minimizing clogging of coating fluid discharge ports and air discharge ports due to drying of the coating fluid.Solution to Problem

[0010] [1] The present invention to solve the above-described problem is a coating device configured to apply coating fluid in a form of droplets onto a substrate being conveyed, the coating device including: a coating fluid discharge nozzle including a plurality of coating fluid discharge ports arranged in a width direction of a substrate; and at least two gas discharge nozzles for blowing gas to a plurality of columnar coating fluids discharged from the coating fluid discharge ports. The two gas discharge nozzles are provided with gas discharge ports between which a row of the coating fluid discharge ports is interposed as observed from a discharge direction of the coating fluid, the gas discharge ports being provided so as to be positioned at a location away from a virtual plane toward the substrate, the virtual plane passing through the coating fluid discharge ports and orthogonal to the discharge direction of the coating fluid, an axis extending in a discharge direction of the gas from each gas discharge port forming an angle of less than 90° with an axis extending in the discharge direction of the coating fluid from each coating fluid discharge port as observed from the width direction of the substrate. The coating device of the present invention preferably has the following embodiments [2] and [3]. [2] The coating device according to [1] above, wherein each gas discharge nozzle is provided to be able to change the discharge direction of the gas from each gas discharge port observed from the width direction of the substrate. [3] The coating device according to [1] or [2] above, wherein a distance from an intersection of the axis extending in the discharge direction of the coating fluid from each coating fluid discharge port and the axis extending in the discharge direction of the gas from each gas discharge port to each coating fluid discharge port as observed the coating device from the width direction of the substrate is 2 mm or more. [4] A method for producing a coated substrate of the present invention to solve the above-described problem includes: discharging coating fluid from a plurality of coating fluid discharge ports arranged in a width direction of a substrate toward the substrate being conveyed; blowing gas toward the coating fluid that is at a location away from the coating fluid discharge ports toward the substrate, as observed from the width direction of the substrate being conveyed, from a direction that is symmetric with respect to the coating fluid being discharged and from a direction in which an angle formed between the coating fluid being discharged and a discharge direction of the coating fluid is less than 90°; and applying the coating fluid formed into droplets onto the substrate. The method for producing a coated substrate according to the present invention preferably performs any one of the following [5] to [7]. [5] The method for producing a coated substrate according to [4] above, wherein a distance from the location at which the gas is blown onto the coating fluid to each coating fluid discharge port is 2 mm or more. [6] The method for producing a coated substrate according to [4] or [5] above, wherein the coating fluid contains a solid content. [7] The method for producing a coated substrate according to any one of [4] to [6] above, wherein a solvent of the coating fluid is an organic solvent. Advantageous Effects of Invention

[0011] It is possible, by using the coating device of the present invention, to minimize clogging of the coating fluid discharge port and the air discharge port due to drying of the coating fluid, and stably apply the coating fluid.Brief Description of Drawings

[0012] FIG. 1 is a schematic cross-sectional view of a coating device 100 of the present invention. FIG. 2 is an exploded perspective view illustrating a configuration of a coating fluid discharge nozzle 110 of FIG. 1. FIG. 3 is an exploded perspective view illustrating a configuration of a gas discharge nozzle 120 of FIG. 1. FIG. 4 is a schematic cross-sectional view of the coating device 100 of the present invention and a view illustrating a state during the formation of a coating film using the coating device 100. FIG. 5 is a bottom view of the tip end of the coating fluid discharge nozzle 110 of FIG. 1 as viewed from the coating fluid discharge port side. FIG. 6 is an exploded perspective view illustrating a configuration of a coating fluid discharge nozzle 210 according to another embodiment of the coating fluid discharge nozzle. FIG. 7 is a bottom view of the tip end of the gas discharge nozzle 120 of FIG. 1 as viewed from the gas discharge port side. FIG. 8 is an exploded perspective view illustrating a configuration of a gas discharge nozzle 220 according to another embodiment of the gas discharge nozzle. FIG. 9 is a schematic view illustrating a coated substrate manufacturing device 10 of the present invention. FIG. 10 is a schematic cross-sectional view of a conventional integrated two-fluid nozzle 300. Description of Embodiments

[0013] Desirable embodiments of the present invention will be described below with reference to the drawings. However, the present invention is not limited to the embodiments illustrated in the drawings, and various modifications can be made without departing from the gist of the invention, as long as the object of the invention can be achieved.

[0014] See FIG. 1. FIG. 1 is a schematic cross-sectional view of a coating device 100 according to a first embodiment of the present invention. The coating device 100 includes a coating fluid discharge nozzle 110 that discharges coating fluid, and gas discharge nozzles 120 and 120' that discharge gas.

[0015] See FIG. 2. FIG. 2 is an exploded perspective view illustrating a configuration of the coating fluid discharge nozzle 110 of FIG. 1. The coating fluid discharge nozzle 110 includes coating fluid nozzle blocks 111 and 112 and a coating fluid shim 113. One coating fluid nozzle block 111 has a coating fluid supply port 114 that supplies coating fluid into the coating fluid discharge nozzle 110, and a coating fluid manifold 115 for expanding the coating fluid in the width direction in communication with the coating fluid supply port 114. The coating fluid shim 113 is a comb shim interposed between the coating fluid nozzle blocks 111 and 112, and gaps between comb teeth of the coating fluid shim 113 form a plurality of coating fluid channels in the width direction by combining with the coating fluid nozzle blocks 111 and 112. The gaps between the comb teeth of the coating fluid shim 113 communicate with the coating fluid manifold 115.

[0016] Note that the "width direction" corresponds to a direction orthogonal to a discharging direction X of the coating fluid and a conveyance direction Y (see FIG. 1) of a substrate 1.

[0017] See FIG. 3. FIG. 3 is an exploded perspective view illustrating the configuration of the gas discharge nozzle 120 of FIG. 1, and the gas discharge nozzle 120' of FIG. 1 has the same configuration. The gas discharge nozzle 120 includes gas nozzle blocks 121 and 122 and a gas shim 123. One gas nozzle block 121 has a gas supply port 124 that supplies gas into the gas discharge nozzle 120, and a gas manifold 125 for expanding the gas in the width direction in communication with the gas supply port 124. The gas shim 123 is a shim having a U-shape, and forms a slit-shaped gas channel in the width direction by being interposed between the gas nozzle blocks 121 and 122. In this case, the gas channel of the gas shim 123 communicates with the gas manifold 125.

[0018] See FIG. 1 again. The coating fluid is discharged from coating fluid discharge ports 116 that are located at the tip end of the coating fluid discharge nozzle 110 and arranged in a line in the width direction. The gas is discharged from the gas discharge ports 126 and 126' located at the tip ends of the gas discharge nozzles 120 and 120'. The gas discharge nozzles 120 and 120' are provided such that the gas discharge ports 126 and 126' are arranged, with a row of the coating fluid discharge ports 116 of the coating fluid discharge nozzle 110 interposed therebetween as observed from the discharge direction X of the coating fluid, and the gas discharge ports 126 and 126' are away from a virtual plane A toward the discharge direction X of the coating fluid, the virtual plane A passing through the coating fluid discharge ports 116 and orthogonal to the discharge direction X. In this case, the gas discharge ports 126 and 126' are located on the substrate 1 side with respect to the virtual plane A. Here, the coating device 100 is installed at a predetermined distance from the substrate 1, and the coating fluid discharge ports 116 of the coating fluid discharge nozzle 110 are arranged such that an extension line of the discharge direction X of the coating fluid intersects the substrate 1. The coating fluid discharge nozzle 110 and the gas discharge nozzles 120 and 120' extend in a direction orthogonal to the conveyance direction Y of the substrate 1, that is, in the width direction of the substrate 1.

[0019] See FIG. 4. FIG. 4 is a schematic cross-sectional view of the coating device 100 of the present invention and illustrates a state in which coating fluid is applied to a substrate using the coating device 100. First, the coating fluid 2 supplied to the coating fluid discharge nozzle 110 is discharged from a plurality of coating fluid discharge ports 116 provided at the tip end of the coating fluid discharge nozzle 110, and the discharged coating fluid continuously forms a columnar coating fluid 3. Next, the columnar coating fluid 3 collides with the gas discharged from the gas discharge ports 126 and 126' provided at the tip ends of the gas discharge nozzles 120 and 120' at a collision point B, and is converted into fine droplets 4. The collision point B is an intersection between an axis extending in the discharge direction X of the coating fluid from the coating fluid discharge ports 116 and an axis extending in the discharge direction of the gas from the gas discharge ports 126 and 126'. The fine droplets 4 land on the substrate 1 being conveyed and form a coating film 5. Here, since the gas discharge ports 126 and 126' are located away from the virtual plane A in the discharge direction X of the coating fluid, the gas discharged from the gas discharge ports 126 and 126' does not attenuate by hitting the coating fluid discharge nozzle 110, and furthermore, the discharged gas does not directly hit the coating fluid discharge ports 116. That is, drying of the coating fluid at the coating fluid discharge ports 116 can be suppressed. In this case, since the gas discharged from the gas discharge ports 126 and 126' diffuses as it moves away from the gas discharge ports 126 and 126', it is preferable that a distance L1 between the coating fluid discharge ports 116 and the collision point B is 2 mm or more so that the gas is not directly blown onto the coating fluid discharge ports 116. Since the coating fluid discharge nozzle 110 having the coating fluid discharge ports 116 and the gas discharge nozzles 120 and 120' having the gas discharge ports 126 and 126' are independently arranged from each other, even though the coating fluid spreads from the coating fluid discharge ports 116, the coating fluid does not reach the gas discharge ports 126 and 126', and the coating fluid does not dry at the gas discharge ports 126 and 126'.

[0020] It is also preferable that distances L2 and L2' between the gas discharge ports 126 and 126' and the collision point B are 2 mm or more in order to prevent the columnar coating fluid 3 discharged from the coating fluid discharge nozzle 110 from adhering to the gas discharge ports 126 and 126'. In addition, in order to convert the columnar coating fluid 3 into the fine droplets 4, it is necessary to discharge gas at high speed from the gas discharge nozzles 120 and 120' and cause the gas to collide with the columnar coating fluid 3 at the collision point B. Therefore, in order to obtain the fine droplets 4, it is more preferable that the distances L2 and L2' are 10 mm or less.

[0021] Note that, in order to discharge the coating fluid 2 in a columnar shape from the coating fluid discharge ports 116, it is necessary to forcefully discharge the coating fluid 2 from each of the coating fluid discharge ports 116, and the discharge amount may be appropriately adjusted according to the type and viscosity of the coating fluid 2. As a result of intensive studies by the inventor, the average flow rate of the coating fluid 2 in the comb-shaped coating fluid channel inside the coating fluid discharge nozzle 110 is preferably 2 m / s or more, and more preferably 5 m / s or more in order to stabilize the shape of the columnar coating fluid 3 after discharge regardless of the type and viscosity of the coating fluid 2.

[0022] On the other hand, in order to form the columnar coating fluid 3 into the fine droplets 4, it is necessary to vigorously discharge gas from the gas discharge ports 126 and 126'. As a result of intensive studies by the inventor, the average flow velocity of the gas in the slit-shaped gas channel inside the gas discharge nozzles 120 and 120' is preferably 100 m / s or more. Furthermore, assuming a case where the shape of the columnar coating fluid 3 is not stable, such as immediately after the start of discharge of the coating fluid, the gas discharge nozzles 120 and 120' may have a retraction mechanism.

[0023] The gas discharge nozzles 120 and 120' are installed such that the discharge direction of the gas can be optionally changed, and angles θ and θ' (hereinafter referred to as a "collision angles θ and θ'") formed between the discharge direction X of the coating fluid discharged from the coating fluid discharge ports 116 and each axis extending in the discharge direction of the gas from the gas discharge ports 126 and 126' can be optionally changed. In order to cause the droplets 4 atomized at the collision point B to fly toward the substrate 1 and land thereon, it is necessary that each of the collision angles θ and θ' are less than 90°. In addition, since the collision angles θ and θ' affect the size of the droplets deposited on the substrate 1, the collision angles θ and θ' may be appropriately changed, the size of the droplets can be reduced by increasing the collision angles θ and θ', and the size of the droplets can be increased by decreasing the collision angles θ and θ'.

[0024] In addition, the gas discharge nozzles 120 and 120' do not need to be installed symmetrically with respect to the discharge direction X of the coating fluid discharged from the coating fluid discharge ports 116, and may be installed asymmetrically with respect to the coating fluid discharge nozzle 110. That is, the gas discharged from the gas discharge nozzles 120 and 120' may respectively collide with the columnar coating fluid 3 at the collision points B and B', and the distances L2 and L2' and the collision angles θ and θ' can be optionally changed.

[0025] See FIG. 5. FIG. 5 is a bottom view of the coating fluid discharge nozzle 110 when the tip end of the coating fluid discharge nozzle 110 of FIG. 1 is viewed from the coating fluid discharge port side. The coating fluid discharge ports 116 of the coating fluid discharge nozzle 110 are rectangular opening portions and are arranged at a predetermined interval W1 (hereinafter referred to as the "arrangement pitch") in the longitudinal direction of the coating fluid discharge nozzle 110, and the total of all the coating fluid discharge ports 116 defines a coating fluid discharge width W2. In this case, the width of the coating film that can be formed on the substrate 1 is substantially the same as the coating fluid discharge width W2. It is preferable that an opening width W3 of each coating fluid discharge port 116 is 50 µm or more so that the rate of change in the opening area remains small even though a manufacturing variation of about 5 µm occurs between discharge ports, and it is preferable that a thickness t1 of the coating fluid shim 113 is 50 µm or more so that the rate of change in the opening area is reduced even though a thickness variation of about 5 µm occurs in the shim. In addition, the opening area of each of the coating fluid discharge ports 116 may be appropriately adjusted depending on the viscosity of the coating fluid to be used and the flow rate of the coating fluid to be discharged, and, in order to cause the coating fluid discharged from the coating fluid discharge ports 116 to have a constant flow rate and discharge the coating fluid in a columnar shape, it is preferable to set the opening area to 50,000 µm 2< or less so that the average flow rate does not decrease, and it is more preferable to set the opening area to 20,000 µm 2< or less. The arrangement pitch W1 of the coating fluid discharge ports is preferably 10 mm or less from the viewpoint of coating film uniformity. Furthermore, the coating fluid discharge width W2 is preferably smaller than the substrate width in order to minimize scattering of the coating fluid to the outside of the system.

[0026] See FIG. 6. FIG. 6 is an exploded perspective view illustrating a configuration of a coating fluid discharge nozzle 210 according to another embodiment of the coating fluid discharge nozzle. The coating fluid discharge nozzle 210 includes coating fluid nozzle blocks 211 and 212. One coating fluid nozzle block 211 has a coating fluid supply port 214 that supplies coating fluid into the coating fluid discharge nozzle 210. The other coating fluid nozzle block 212 has a coating fluid manifold 215 for expanding the coating fluid in the width direction and a coating fluid discharge channel 217 communicating with the coating fluid manifold 215, and a coating fluid discharge port 216 is formed at the tip end of the coating fluid discharge channel 217. The shape of the coating fluid discharge port 216 is not limited to a rectangle, and may be a circle or an ellipse.

[0027] See FIG. 7. FIG. 7 is a bottom view of the gas discharge nozzle 120 when the tip end of the gas discharge nozzle 120 of FIG. 1 is viewed from the gas discharge port side. The gas discharge port 126 of the gas discharge nozzle 120 has a slit shape, and the width of the gas discharge port 126 is a gas discharge width W4. Here, two-dot chain lines indicated by reference numerals 116L and 116R indicate locations of both ends of the coating fluid discharge width W2 in the coating fluid discharge nozzle 110. The gas discharge width W4 is longer than the coating fluid discharge width W2 in order to form all the columnar coating fluids 3 discharged from the respective coating fluid discharge ports 116 into the fine droplets 4. The shape of the gas discharge port 126 is not limited to one slit continuous in the width direction as illustrated in FIGS. 3 and 7, and may be intermittently opened in the width direction so as to correspond to the coating fluid discharge ports 116 on a one-to-one basis. In a case of opening intermittently, the opening length in the width direction is preferably larger than the width W3 of each of the coating fluid discharge ports 116.

[0028] See FIG. 8. FIG. 8 is an exploded perspective view illustrating a configuration of a gas discharge nozzle 220 according to another embodiment of the gas discharge nozzle. The gas discharge nozzle 220 includes gas nozzle blocks 221 and 222. One gas nozzle block 221 has a gas supply port 224 that supplies gas into the gas discharge nozzle 220. The other gas nozzle block 222 has a gas manifold 225 for expanding the gas in the width direction and a gas discharge channel 227 communicating with the gas manifold 225, and a gas discharge port 226 is formed at the tip end of the gas discharge channel 227. The shape of the gas discharge port 226 is not limited to a rectangle, and may be a circle or an ellipse.

[0029] As described above, by using the spray coating device according to the present invention, even when coating fluid containing a solid content is discharged, the coating fluid can be stably applied without clogging the coating fluid discharge ports or the gas discharge ports.

[0030] Next, a coated substrate manufacturing device 10 for manufacturing a coated substrate using the coating device 100 of the present invention will be described with reference to FIG. 9. FIG. 9 is a schematic view illustrating an example of a coated substrate manufacturing device 10 of the present invention.

[0031] The coated substrate manufacturing device 10 includes an unwinding unit 11 that unwinds the substrate 1 and a winding unit 12 that winds a coated substrate 6. The coating device 100 that applies coating fluid to the substrate 1 and a drying device 13 that dries a coating film are provided between the unwinding unit 11 and the winding unit 12. In addition, in order to suppress changes of the distance between the coating device 100 and the substrate 1 over time, which are caused by vibration of the substrate 1 due to the gas discharged from the coating device 100, a backup roll 14 is provided on the opposite side of the coating device 100 across the substrate 1, and is in contact with the substrate 1 to support the substrate 1. In this case, by having the substrate 1 trained around the backup roll 14, the backup roll 14 rotates as the substrate 1 is conveyed and it is also possible to prevent the substrate 1 from sliding on the backup roll 14 and being damaged. Furthermore, as a coating fluid discharge mechanism, the coated substrate manufacturing device 10 is provided with a liquid feeding pump 15 that supplies the coating fluid to the coating device 100 and a tank 16 that stores the coating fluid, and as a gas discharge mechanism, the coated substrate manufacturing device 10 is provided with a pressurized gas source 17 for supplying gas to the coating device 100, a branch pipe 18 for branching the gas to each gas discharge nozzle, and pressure regulating valves 19 and 19' that individually adjust the pressure of the gas supplied from each gas discharge nozzle. The coating device 100 and the backup roll 14 are enclosed by a booth 20, and a bottom portion of the booth 20 has an opening portion 21 that is in communication with a waste liquid collection tank 22.

[0032] The booth 20 prevents some droplets scattered without adhering to the substrate 1, among the fine droplets 4 discharged and formed from the coating device 100, from scattering to the surroundings. The coating fluid adhering to the inner wall of the booth 20 drips down along the inner wall of the booth 20, and is collected in the waste liquid collection tank 22 through the bottom opening portion 21. Since the booth 20 and the waste liquid collection tank 22 are in contact with the coating fluid, it is preferable to select a material according to the coating fluid, and for example, in a case where the solvent of the coating fluid is acetone that is a low-boiling point organic solvent, it is preferable to use a metal or a resin material having excellent acetone resistance, for example, a fluororesin.

[0033] In the coated substrate manufacturing device 10 illustrated in FIG. 9, the coating fluid discharge direction from the coating device 100 is the vertically downward direction, and the conveyance direction of the substrate 1 of the portion is the horizontal direction; however, the present invention is not limited thereto as long as the coating device 100 is installed so as to substantially face a coating surface of the substrate 1, and for example, the coating fluid discharge direction from the coating device 100 may be the horizontal direction, and the conveyance direction of the portion may be the vertical direction.

[0034] Next, a method for producing a coated substrate using the coating device 100 of the present invention will be described again with reference to FIG. 4. The coated substrate is produced by forming the coating film 5 on the substrate 1 by the coating device 100. In this case, since the basis weight of the coating film 5 can be controlled by the flow rate of the coating fluid 2 supplied to the coating fluid discharge nozzle 110, it is preferable to have a means for measuring the basis weight of the formed coating film 5 to adjust the supply flow rate of the coating fluid 2. The size of the attached droplets is determined by the flow rate and the collision angles θ and θ' of the gas supplied to the gas discharge nozzles 120 and 120'. In order to reduce the size of the droplets, the flow rate of the gas supplied to the gas discharge nozzles 120 and 120' is increased, or the collision angles θ and θ' are increased. On the other hand, in a case where it is desired to increase the size of the droplets, the size of the droplets can be adjusted by decreasing the flow rate of the gas supplied to the gas discharge nozzles 120 and 120' or decreasing the collision angles θ and θ'.

[0035] In addition, immediately after the start of discharging the coating fluid, the discharge pressure of the coating fluid 2 from the coating fluid discharge ports 116 of the coating fluid discharge nozzle 110 is low, and until the pressure rises to a predetermined discharge pressure, the shape of the columnar coating fluid 3 may not be stable. Therefore, it is preferable to retract the gas supply nozzles 120 and 120' in advance so that the coating fluid does not scatter to the gas supply nozzles 120 and 120' until a stable columnar coating fluid 3 is formed. Thereafter, after the shape of the columnar coating fluid 3 is stabilized, the gas discharge nozzles 120 and 120' are brought close to the columnar coating fluid 3, and the gas is discharged from the gas discharge ports 126 and 126'. As a result, since the coating fluid 2 does not adhere to the gas discharge ports 126 and 126', stable coating can be performed without clogging of the gas discharge ports 126 and 126'.

[0036] The coating device of the present invention can obtain a large effect particularly on coating fluid containing a solid content, such as a solution of an inorganic substance or an organic substance or a dispersion of an inorganic substance or an organic substance dispersed in a solvent. The viscosity of the coating fluid may be any viscosity as long as the coating fluid can be refined by collision of the discharged gas, and as the viscosity is lower, fine droplets can be formed. In general, when the viscosity is 500 mPa·s or less, a good coating appearance can be obtained. In particular, the viscosity is preferably 2.0 mPa·s or less.

[0037] In addition, in a case where an organic solvent is contained in a part of the solvent of the coating fluid, the effect of the present invention can be particularly obtained. In particular, it is possible to obtain a significant effect on coating fluid containing at least one of acetaldehyde, acetone, acetonitrile, allyl alcohol, benzene, 2-butanol, methyl ethyl ketone, tert-butyl alcohol, carbon disulfide, chloroform, cyclohexane, 1,2-dichloroethane, dichloromethane, diethyl ether, ethanol, anhydrous ethanol, ethyl acetate, 1,2-dimethoxyethane, ethyl formate, ethyl propionate, heptane, hexane, ligroin, methanol, methyl acetate, methyl propionate, pentane, petroleum benzine, 1-propanol, propylene oxide, n-propyl ether, tetrahydrofuran, trichloroethylene, triethylamine, and trifluoroacetic acid, which are low-boiling organic solvents having a boiling point of 100°C or lower.

[0038] The type of gas or atmospheric gas component used in the present invention is not particularly limited as long as it is suitable for coating, and air, nitrogen gas, and the like can be used. The ambient pressure of the external atmosphere is not particularly limited, and may be set to an atmospheric pressure environment or a reduced-pressure environment. In addition, the temperature of the gas or the outside air is not particularly limited, but drying of the fine droplets flying is promoted by using hot air as the gas. As a result, finer droplets can be formed, and the amount of moisture attached to the substrate is reduced, so that the drying load in the subsequent step can also be reduced.[Examples]

[0039] Hereinafter, the present invention will be described in more detail with reference to Examples. Note that the present invention is not limited to the following Examples.<Coating fluid>

[0040] As a solid content, polyvinylidene fluoride, which is a fluororesin, was prepared, and as a solvent, acetone (boiling point: 56°C), which is a low-boiling organic solvent, was prepared to produce coating fluid by mixing them to have a solid content concentration of 5% by weight.[Example 1]

[0041] The coating device 100 of FIG. 1 was mounted in the coated substrate manufacturing device 10 of FIG. 9 to produce a coated substrate 6. A coating film was formed on the substrate 1 unwound from the unwinding unit 11 using the coating device 100, the coating film was completely dried by the drying device 13, and the coated substrate 6 was then wound up by the winding unit 12. Thereafter, the coated substrate 6 that had been wound was taken out, and the presence or absence of droplet adhesion and the coating appearance were evaluated by visual observation and microscopic examination. As coating conditions in the coating device 100, the distance from the virtual plane A passing through the coating fluid discharge ports 116 to the gas discharge ports 126 and 126' was set to 7.5 mm, the distance L1 between the coating fluid discharge ports 116 and the collision point B was set to 10 mm, the distances L2 and L2' between the gas discharge ports 126 and 126' and the collision point B were set to 5 mm, and the collision angles θ and θ' were set to 60° (see FIG. 4). The coating fluid discharge nozzle 110 had a coating fluid discharge width W2 of 210.1 mm, an opening width W3 of the coating fluid discharge port of 100 µm, a thickness t1 of the coating fluid shim of 100 µm, and an arrangement pitch W1 of the coating fluid discharge ports of 7.5 mm. In this case, the number of coating fluid discharge ports 116 is 29 (see FIG. 5). In the gas discharge nozzles 120 and 120', the gas discharge width W4 was 250 mm, and the thickness of the gas shim was 50 µm (see FIG. 7). As a coating procedure, the substrate 1 was conveyed at a speed of 50 m / min, the coating fluid was discharged from the coating fluid discharge nozzle 110 at 100 mL / min, and compressed air was discharged from each of the gas discharge nozzles 120 and 120' at 300 L / min.[Example 2]

[0042] The substrate 1 was coated under the same conditions as those in Example 1 except that the collision angles θ and θ' were 30°.[Example 3]

[0043] The substrate 1 was coated under the same conditions as those in Example 1 except that the distance L1 between the coating fluid discharge ports 116 and the collision point B was 2 mm and the collision angles θ and θ' were 80°.[Comparative Example 1]

[0044] The substrate 1 was coated under the same conditions as those in Example 1 except that the distance L1 between the coating fluid discharge ports 116 and the collision point B was 0.5 mm. In Comparative Example 1, in relation to the distance L1, the gas discharge ports 126 and 126' are located on the opposite side to the substrate 1 side with respect the virtual plane A. That is, the gas discharge ports 126 and 126' according to Comparative Example 1 are located on the coating fluid discharge nozzle 110 side with respect the virtual plane A.[Comparative Example 2]

[0045] The substrate 1 was coated under the same conditions as those in Example 1 except that the collision angles θ and θ' were 90°.[Comparative Example 3]

[0046] The substrate 1 was coated using a conventional integrated two-fluid nozzle 300 illustrated in FIG. 10. The integrated two-fluid nozzle 300 has a longitudinal direction in a direction orthogonal to the conveyance direction Y of the substrate 1, that is, a width direction of the substrate 1 (direction orthogonal to the paper surface), and is installed so as to face the substrate 1 with a certain distance from the substrate 1. The integrated two-fluid nozzle 300 is formed of outer die blocks 301 and 301' and inner die blocks 302 and 302'. The coating fluid is supplied to a coating fluid pocket 303 and discharged from a coating fluid discharge port 304, and the gas is supplied to gas pockets 305 and 305' and discharged from gas discharge ports 306 and 306'. The gas discharge ports 306 and 306' are provided between which the coating fluid discharge port 304 is interposed as observed from the discharge direction of the coating fluid. The coating fluid discharge port 304 and the gas discharge ports 306 and 306' are on the same plane. The substrate 1 was coated in the same procedure as in Example 1 using this integrated two-fluid nozzle 300.<Evaluation Method>

[0047] In the above-described Examples and Comparative Examples, the coating was continuously performed for 30 minutes. The coated state was evaluated using the coated substrate 6 wound by the winding unit 12. The evaluation results are illustrated in Tables 1 and 2. For the droplet attachability in the tables, the adhesion rate of droplets to the substrate was used as a criterion. The adhesion rate of the droplets to the substrate was determined by measuring the basis weight of each of the coated substrate and the substrate before coating to calculate the basis weight of the coating film formed on the substrate, and calculating the ratio of the basis weight to the total solid content contained in the coating fluid supplied to the coating fluid discharge nozzle. As the evaluation on whether droplets could be attached or not, it was determined as "∘" when the total solid content was 30% or more and "×" when the total solid content was less than 30%. In addition, the average particle diameter of the droplets was measured using a laser diffraction particle distribution meter (FLD-319A manufactured by Seika Digital Image Co., Ltd.) for the flying droplets immediately before being attached to the substrate. Note that, incidentally, the average particle diameter illustrated here refers to a Sauter average diameter. In addition, in order to confirm the clogging situation of the coating fluid discharge ports 116 during the coating operation, a pressure gauge (not illustrated) was installed so as to communicate with the coating fluid manifold 115, and the pressure in the coating fluid manifold was measured 15 minutes and 30 minutes after the start of coating. In the coating appearance, the coating missing represents a coating missing region where application is not performed in a streak shape generated in the substrate conveyance direction, and the coating non-uniformity is linear appearance non-uniformity generated in the substrate conveyance direction, and represents coating non-uniformity caused by a difference in the ratio of fluid deposition on the substrate. In addition, for the evaluation of the clogging of the coating fluid discharge ports and the clogging of the gas discharge port, the tip end of each discharge nozzle was observed after continuous coating for 30 minutes, and it was determined that the clogging was present in a case where the clogging was observed even partially. Immediately after the start of coating, the appearance of the coating film was good in all Examples and Comparative Examples, and the pressure in the coating fluid manifold was 0.1 MPa. Table 1Example 1Example 2Example 3Distance L1 between coating fluid discharge port and collision point [mm]10102Distances L2 and L2' between gas discharge port and collision point [mm]555Collision angles θ and θ' [°]603080Droplet attachability○○○○: Droplets are attached (adhesion rate of 30% or more)×: Droplets are not attached (adhesion rate of less than 30%)Average particle diameter of droplets [µm]408030Pressure inside coating fluid manifold (after 15 minutes) [MPa]0.10.10.1Pressure inside coating fluid manifold (after 30 minutes) [MPa]0.10.10.1Coating appearance○○○○: Good×: PoorClogging of coating fluid discharge portAbsence of cloggingAbsence of cloggingAbsence of cloggingClogging of gas discharge portAbsence of cloggingAbsence of cloggingAbsence of clogging Table 2 Comparative Example 1Comparative Example 2Comparative Example 3Distance L1 between coating fluid discharge port and collision point [mm]0.5100.8Distances L2 and L2' between gas discharge port and collision point [mm]551Collision angles θ and θ' [°]609030Droplet attachability××○○: Droplets are attached (adhesion rate of 30% or more)×: Droplets are not attached (adhesion rate of less than 30%)Average particle diameter of droplets [µm]--20Pressure inside coating fluid manifold (after 15 minutes) [MPa]0.10.20.2Pressure inside coating fluid manifold (after 30 minutes) [MPa]0.10.30.4Coating appearance--×○: GoodCoating missing×: PoorCoating non-uniformityClogging of coating fluid discharge portAbsence of cloggingPresence of cloggingPresence of cloggingClogging of gas discharge portAbsence of cloggingAbsence of cloggingPresence of clogging [Comparison between Example 1 and Comparative Example 3]

[0048] In the conventional integrated two-fluid nozzle 300 described in Comparative Example 3, the solid content of the coating fluid was precipitated at both the coating fluid discharge port 304 and the gas discharge ports 306 and 306' after 30 minutes from the start of coating, and the clogging was confirmed at each discharge port. In addition, due to this, a streak-like coating missing region and linear application unevenness were observed on the substrate after coating. Furthermore, the pressure of the coating fluid manifold increased to 0.2 MPa when 15 minutes had elapsed from the start of coating. When the coating fluid discharge port is clogged, the opening area of the coating fluid discharge port is reduced. Therefore, when a fixed amount of the coating fluid is continuously fed by the liquid feeding pump, the pressure inside the coating fluid manifold increases. That is, it was confirmed that a part of the coating fluid discharge port 304 was clogged in a short time until 15 minutes elapsed from the start of coating. On the other hand, in Example 1, the pressure inside the coating fluid manifold did not increase even 30 minutes after the start of coating, the coating fluid discharge ports 116 and the gas discharge ports 126 and 126' were not clogged, and the coating film 5 having a good coating appearance could be formed.[Comparison between Example 1 and Example 2]

[0049] In Example 2, it was confirmed that by reducing the collision angles θ and θ', the average particle diameter of droplets was increased as compared with Example 1. That is, it was confirmed that the force of colliding with the columnar coating fluid 3 can be controlled by changing the collision angles θ and θ', and the average particle diameter of the droplets can be changed to a desired size. In addition, in both of Examples 1 and 2, the pressure inside the coating fluid manifold did not increase even after a lapse of 30 minutes from the start of coating, the coating fluid discharge ports 116 and the gas discharge ports 126 and 126' were not clogged, and the coating film 5 having a good coating appearance could be formed.[Comparison between Example 1 and Example 3]

[0050] In Example 3, the distance L1 between the coating fluid discharge port and the collision point was set to 2 mm, and the collision angles θ and 0' were set to 80° so that the gas discharge ports 126 and 126' were located away from the virtual plane A toward the substrate 1 side. It was confirmed that the average particle diameter of the droplets was reduced by increasing the collision angles θ and θ' as compared with Example 1. In addition, in both of Examples 1 and 3, the pressure inside the coating fluid manifold did not increase even after a lapse of 30 minutes from the start of coating, the coating fluid discharge ports 116 and the gas discharge ports 126 and 126' were not clogged, and the coating film 5 having a good coating appearance could be formed.[Comparison between Example 1 and Comparative Example 1]

[0051] In Comparative Example 1, the gas discharge ports 126 and 126' are located on the side opposite to the substrate 1 side with respect to the virtual plane A. The gas discharged from the gas discharge ports 126 and 126' did not hit the columnar coating fluid 3 by hitting the coating fluid discharge nozzle 110, and the atomized droplets 4 were not formed. Thereafter, in order to apply the gas discharged from the gas discharge ports 126 and 126' to the columnar coating fluid 3, the collision angles θ and θ' were adjusted while the locations of the gas discharge ports 126 and 126' were fixed, but in the range of L2 ≤ 10 mm, the atomized droplets 4 could not be formed, and in the range of L2 > 10 mm, the gas colliding with the columnar coating fluid 3 was attenuated, and the fine droplets 4 could not be formed.[Comparison between Example 1 and Comparative Example 2]

[0052] In Comparative Example 2, the collision angles θ and θ' are 90°. Therefore, the atomized droplets 4 micronized at the collision point B did not move toward the substrate 1, and as a result, the droplet adhesion rate was significantly reduced to 10%. Further, a part of the fine droplets 4 directed to the coating fluid discharge ports 116 was precipitated at the coating fluid discharge ports 116, and a part of the coating fluid discharge ports 116 was clogged.Industrial Applicability

[0053] The present invention can be applied to the coating device for forming a coating film on the substrate film of a resin, paper, a metal thin film, cloth, or the like, and a coated substrate producing device including the coating device and a coated substrate producing method, but is not limited thereto.Reference Signs List

[0054] 1 Substrate 2 Coating fluid 3 Columnar coating fluid 4 Fine droplet 5 Coating film 6 Coated substrate 10 Coated substrate manufacturing device 11 Unwinding unit 12 Winding unit 13 Drying device 14 Backup roll 15 Liquid feeding pump 16 Tank 17 Pressurized gas source 18 Branch pipe 19, 19' Pressure regulating valve 20 Booth 21 Bottom opening portion 22 Waste liquid collection tank 100 Coating device 110 Coating fluid discharge nozzle 111, 112 Coating fluid nozzle block 113 Coating fluid shim 114 Coating fluid supply port 115 Coating fluid manifold 116 Coating fluid discharge port 120, 120' Gas discharge nozzle 121, 122 Gas nozzle block 123 Gas shim 124 Gas supply port 125, 125' Gas manifold 126, 126' Gas discharge port 210 Coating fluid discharge nozzle 211, 212 Coating fluid nozzle block 214 Coating fluid supply port 215 Coating fluid manifold 216 Coating fluid discharge port 217 Coating fluid discharge channel 220 Gas discharge nozzle 221, 222 Gas nozzle block 224 Gas supply port 225 Gas manifold 226 Gas discharge port 227 Gas discharge channel 300 Integrated two-fluid nozzle 301, 301' Outer die block 302, 302' Inner die block 303 Coating fluid pocket 304 Coating fluid discharge port 305, 305' Gas pocket 306, 306' Gas discharge port A Virtual plane B, B' Collision point L1 Distance between coating fluid discharge port and collision point L2, L2' Distance between gas discharge port and collision point t1 Thickness of coating fluid shim W1 Arrangement pitch of coating fluid discharge ports W2 Coating fluid discharge width W3 Opening width of each coating fluid discharge port W4 Gas discharge width X Discharge direction of coating fluid Y Conveyance direction of substrate θ, θ' Collision angle

Examples

example 1

[Example 1]

[0041]The coating device 100 of FIG. 1 was mounted in the coated substrate manufacturing device 10 of FIG. 9 to produce a coated substrate 6. A coating film was formed on the substrate 1 unwound from the unwinding unit 11 using the coating device 100, the coating film was completely dried by the drying device 13, and the coated substrate 6 was then wound up by the winding unit 12. Thereafter, the coated substrate 6 that had been wound was taken out, and the presence or absence of droplet adhesion and the coating appearance were evaluated by visual observation and microscopic examination. As coating conditions in the coating device 100, the distance from the virtual plane A passing through the coating fluid discharge ports 116 to the gas discharge ports 126 and 126' was set to 7.5 mm, the distance L1 between the coating fluid discharge ports 116 and the collision point B was set to 10 mm, the distances L2 and L2' between the gas discharge ports 126 and 126' and the collisi...

example 2

[Example 2]

[0042]The substrate 1 was coated under the same conditions as those in Example 1 except that the collision angles θ and θ' were 30°.

example 3

[Example 3]

[0043]The substrate 1 was coated under the same conditions as those in Example 1 except that the distance L1 between the coating fluid discharge ports 116 and the collision point B was 2 mm and the collision angles θ and θ' were 80°.

Claims

1. A coating device configured to apply coating fluid in a form of droplets onto a substrate being conveyed, the coating device comprising: a coating fluid discharge nozzle including a plurality of coating fluid discharge ports arranged in a width direction of a substrate; and at least two gas discharge nozzles for blowing gas to a plurality of columnar coating fluids discharged from the coating fluid discharge ports, wherein the two gas discharge nozzles are provided with gas discharge ports between which a row of the coating fluid discharge ports is interposed as observed from a discharge direction of the coating fluid, the gas discharge ports being provided so as to be positioned at a location away from a virtual plane toward the substrate, the virtual plane passing through the coating fluid discharge ports and orthogonal to the discharge direction of the coating fluid, an axis extending in a discharge direction of the gas from each gas discharge port forming an angle of less than 90° with an axis extending in the discharge direction of the coating fluid from each coating fluid discharge port as observed from the width direction of the substrate.

2. The coating device according to claim 1, wherein each gas discharge nozzle is provided to be able to change the discharge direction of the gas from each gas discharge port observed from the width direction of the substrate.

3. The coating device according to claim 1 or 2, wherein a distance from an intersection of the axis extending in the discharge direction of the coating fluid from each coating fluid discharge port and the axis extending in the discharge direction of the gas from each gas discharge port to each coating fluid discharge port as observed the coating device from the width direction of the substrate is 2 mm or more.

4. A method for producing a coated substrate, the method comprising: discharging coating fluid from a plurality of coating fluid discharge ports arranged in a width direction of a substrate toward the substrate being conveyed; blowing gas toward the coating fluid that is at a location away from the coating fluid discharge ports toward the substrate, as observed from the width direction of the substrate being conveyed, from a direction that is symmetric with respect to the coating fluid being discharged and from a direction in which an angle formed between the coating fluid being discharged and a discharge direction of the coating fluid is less than 90°; and applying the coating fluid formed into droplets onto the substrate.

5. The method for producing a coated substrate according to claim 4, wherein a distance from the location at which the gas is blown onto the coating fluid to each coating fluid discharge port is 2 mm or more.

6. The method for producing a coated substrate according to claim 4 or 5, wherein the coating fluid contains a solid content.

7. The method for producing a coated substrate according to claim 4 or 5, wherein a solvent of the coating fluid is an organic solvent.

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