WO2025052843A1 - Coating device, and method for manufacturing substrate with coating film - Google Patents

Abstract

This coating device comprises: a coating liquid discharge nozzle that has a plurality of coating liquid discharge ports arranged in the width direction of a traveling substrate; and two or more gas discharge nozzles for blowing a gas onto a plurality of columnar jets of a coating fluid discharged from these coating fluid discharge ports. When viewed in the discharge direction of the coating fluid, these two gas discharge nozzles are disposed so that gas discharge ports of the gas discharge nozzles sandwich a row of the plurality of coating liquid discharge ports and the gas discharge ports are located so as to be separated, toward the substrate, from a virtual plane passing through the coating liquid discharge ports and perpendicular to the discharge direction of the coating liquid, and, when viewed in the width direction of the substrate, the angles formed by axes extending from the gas discharge ports in the discharge direction of the gas with axes extending from the coating liquid discharge ports in the discharge direction of the coating liquid are less than 90°.

Description

Coating device and method for producing coated substrate

The present invention relates to a coating device that applies a coating liquid in droplet form to a substrate such as a film, nonwoven fabric, or paper, and a method for manufacturing a substrate with a coating film.

　Conventionally, spray coating devices are known as coating devices that apply coating liquid to a substrate in the form of droplets. From the standpoint of substrate productivity and functionality, this type of spray coating device is required to apply minute droplets uniformly over almost the entire surface of a wide substrate.

As an example of an application device for such a case, Patent Document 1 discloses a two-fluid slot-type spray nozzle (hereinafter, "spray nozzle" will also be simply referred to as "nozzle") that can spray the coating liquid by discharging compressed air simultaneously with the coating liquid, forming droplets of the coating liquid using the discharged air. This spray nozzle has multiple coating liquid discharge ports in the width direction of the substrate, and air discharge ports are arranged to sandwich the coating liquid discharge ports from the upstream and downstream sides in the substrate transport direction. Therefore, the discharged droplet-like coating liquid forms a continuous band in the width direction of the substrate, and a uniform coating film can be formed without uneven coating thickness or application.

JP 2006-026576 A

However, in the slot-type spray nozzle disclosed in Patent Document 1, an air outlet is disposed near the coating liquid outlet, and the discharged air promotes drying of the coating liquid at the coating liquid outlet. At this time, if the coating liquid contains solids, the solids may precipitate as the coating liquid dries, causing the coating liquid outlet to become clogged or the opening area to become smaller due to the precipitated solids. When the coating liquid outlet becomes clogged or its opening area becomes smaller, continuous streaks of coating loss in the transport direction or areas with small coating thickness are formed at the coating position corresponding to the clogged area.
In addition, in a slot-type spray nozzle, the coating liquid outlet and the air outlet are located at the same height and on approximately the same plane, so the coating liquid from the coating liquid outlet may wet and spread, reach the air outlet, and dry at the air outlet. At this time, if the coating liquid contains solids, the solids may precipitate as the coating liquid dries, causing the air outlet to become clogged or its opening area to become smaller. If the air outlet is clogged or its opening area becomes smaller, the coating liquid cannot be sufficiently ejected at that location, resulting in uneven coating, or the coating liquid that is not ejected may accumulate near the coating liquid outlet and then fall onto the substrate, significantly worsening the coating appearance.
Furthermore, when the coating liquid contains an organic solvent with a low boiling point, the coating liquid dries quickly, and clogging of the coating liquid discharge port and air discharge port due to precipitation of solids becomes a more serious problem.

As described above, in a coating device that applies droplets of coating liquid to a substrate such as a film, nonwoven fabric, or paper, no spray coating device has been found that can apply a coating liquid while preventing clogging of the coating liquid outlet and air outlet due to drying of the coating liquid, even when the coating liquid contains solids.

The present invention provides a spray coating device and a method for manufacturing a coated substrate that can prevent clogging of the coating fluid outlet and air outlet due to drying of the coating fluid.

[1] The present invention solves the above-mentioned problems by providing a coating device that applies a coating liquid in droplet form to a traveling substrate, comprising:
a coating liquid discharge nozzle having a plurality of coating liquid discharge ports arranged in a width direction of the substrate;
at least two gas ejection nozzles for blowing gas onto the plurality of columnar coating liquids ejected from the coating liquid ejection port,
The two gas discharge nozzles are:
When observed from the direction in which the coating liquid is discharged, the gas discharge ports are positioned between the rows of the coating liquid discharge ports,
The gas discharge port is provided so as to be located toward the substrate away from an imaginary plane that passes through the coating liquid discharge port and is perpendicular to the coating liquid discharge direction, and when observed from the width direction of the substrate, an angle between an axis extending in the gas discharge direction from the gas discharge port and an axis extending in the coating liquid discharge direction from the coating liquid discharge port is less than 90°.

The coating device of the present invention is preferably in the following embodiment [2] or [3].
[2] The coating device according to [1] above, wherein the gas discharge nozzle can change a discharge direction of the gas from the gas discharge port when observed from a width direction of the substrate.

[3] The coating device according to [1] or [2] above, wherein, when the coating device is observed from the width direction of the substrate, the distance from the intersection of an axis extending in the coating liquid discharge direction from the coating liquid discharge port and an axis extending in the gas discharge direction from the gas discharge port to the coating liquid discharge port is 2 mm or more.
[4] The method for producing a substrate having a coating film according to the present invention, which solves the above problems, comprises:
A coating liquid is discharged from a plurality of coating liquid discharge ports arranged in a width direction of the substrate toward the traveling substrate;
blowing gas toward the coating liquid at a position away from the coating liquid discharge port toward the substrate from a direction that is symmetrical with respect to the discharged coating liquid and forms an angle of less than 90° with the discharge direction of the coating liquid when observed from the width direction of the traveling substrate;
The coating liquid in the form of droplets is applied onto a substrate.

The method for producing a substrate having a coating film of the present invention is preferably any one of the following steps [5] to [7].
[5] The method for producing a substrate with a coating film according to [4] above, wherein the distance from the position at which the gas is blown in the coating liquid to the coating liquid discharge port is 2 mm or more.
[6] The method for producing a substrate having a coating film according to the above [4] or [5], wherein the coating liquid contains solids.
[7] The method for producing a substrate with a coating film according to any one of the above [4] to [6], wherein the solvent for the coating liquid is an organic solvent.

By using the coating device of the present invention, clogging of the coating fluid outlet and air outlet due to drying of the coating fluid can be prevented, and the coating fluid can be applied stably.

FIG. 1 is a schematic cross-sectional view of a coating apparatus 100 of the present invention. FIG. 2 is an exploded perspective view showing the configuration of the coating fluid discharge nozzle 110 of FIG. FIG. 3 is an exploded perspective view showing the configuration of the gas discharge nozzle 120 of FIG. FIG. 4 is a schematic cross-sectional view of the coating apparatus 100 of the present invention and a diagram showing a state in which a coating film is formed using the coating apparatus 100. FIG. 5 is a bottom view of the tip of the coating fluid discharge nozzle 110 in FIG. 1, as viewed from the coating fluid discharge port side. FIG. 6 is an exploded perspective view illustrating the configuration of a coating fluid discharging nozzle 210 according to another embodiment of the coating fluid discharging nozzle. FIG. 7 is a bottom view of the tip of the gas discharge nozzle 120 in FIG. 1 as viewed from the gas discharge port side. FIG. 8 is an exploded perspective view showing the configuration of a gas ejection nozzle 220 according to another embodiment of the gas ejection nozzle. FIG. 9 is a schematic diagram showing an apparatus 10 for producing a coated substrate according to the present invention. FIG. 10 is a schematic cross-sectional view of a conventional integrated two-fluid nozzle 300 .

The preferred embodiment of the present invention will be described with reference to the drawings. However, the present invention is not limited to the form shown in the drawings, and various modifications are possible as long as the object of the invention can be achieved and the gist of the invention is not deviated from.

Refer to Figure 1. Figure 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 is composed of a coating liquid discharge nozzle 110 for discharging a coating liquid, and gas discharge nozzles 120, 120' for discharging a gas.

Please refer to FIG. 2. FIG. 2 is an exploded perspective view showing the configuration of the coating liquid discharge nozzle 110 of FIG. 1. The coating liquid discharge nozzle 110 is composed of coating liquid nozzle blocks 111, 112 and a coating liquid shim 113. One of the coating liquid nozzle blocks 111 has a coating liquid supply port 114 that supplies the coating liquid to the inside of the coating liquid discharge nozzle 110, and a coating liquid manifold 115 that communicates with the coating liquid supply port 114 and spreads the coating liquid in the width direction. The coating liquid shim 113 is a comb-shaped shim sandwiched between the coating liquid nozzle blocks 111, 112, and by combining with the coating liquid nozzle blocks 111, 112, the gaps between the comb teeth of the coating liquid shim 113 form a plurality of coating liquid flow paths in the width direction. In addition, the gaps between the comb teeth of the coating liquid shim 113 communicate with the coating liquid manifold 115.
The "width direction" corresponds to a direction perpendicular to the discharge direction X of the coating liquid and the transport direction Y of the substrate 1 (see FIG. 1).

Refer to FIG. 3. FIG. 3 is an exploded perspective view showing the configuration of the gas discharge nozzle 120 in FIG. 1, and the gas discharge nozzle 120' in FIG. 1 has a similar configuration. The gas discharge nozzle 120 is composed of gas nozzle blocks 121, 122 and a gas shim 123. One of the gas nozzle blocks 121 has a gas supply port 124 that supplies gas into the gas discharge nozzle 120, and a gas manifold 125 that communicates with the gas supply port 124 and spreads the gas in the width direction. The gas shim 123 is a U-shaped shim, and is sandwiched between the gas nozzle blocks 121, 122 to form a slit-shaped gas flow path in the width direction. At this time, the gas flow path of the gas shim 123 communicates with the gas manifold 125.

Refer to FIG. 1 again. The coating liquid is discharged from the coating liquid outlets 116 located at the tip of the coating liquid discharge nozzle 110 and aligned in a row in the width direction. The gas is discharged from the gas outlets 126, 126' located at the tip of the gas discharge nozzles 120, 120'. When observed from the coating liquid discharge direction X, the gas outlets 126, 126' are arranged so that the gas outlets 126, 126' sandwich the row of coating liquid outlets 116 of the coating liquid discharge nozzle 110, and the gas outlets 126, 126' are located farther away in the coating liquid discharge direction X than the imaginary plane A that passes through the coating liquid outlets 116 and is perpendicular to the coating liquid discharge direction X. In this case, the gas outlets 126, 126' are located closer to the substrate 1 than the imaginary plane A. Here, the coating device 100 is installed at a certain distance from the substrate 1, and the coating liquid discharge port 116 of the coating liquid discharge nozzle 110 is arranged so that an extension line of the coating liquid discharge direction X intersects with the substrate 1. The coating liquid discharge nozzle 110 and the gas discharge nozzles 120, 120' extend in the short direction of the substrate 1, i.e., in a direction perpendicular to the transport direction Y of the substrate 1.

Refer to FIG. 4. FIG. 4 is a schematic cross-sectional view of the coating device 100 of the present invention and a diagram showing the state of coating a substrate using the coating device 100. First, the coating liquid 2 supplied to the coating liquid discharge nozzle 110 is discharged from a plurality of coating liquid discharge ports 116 provided at the tip of the coating liquid discharge nozzle 110, and the discharged coating liquid is continuously connected to form a columnar coating liquid 3. Next, the columnar coating liquid 3 collides with the gas discharged from the gas discharge ports 126, 126' provided at the tip of the gas discharge nozzle 120, 120' at a collision point B, and becomes fine droplets 4. The collision point B is the intersection point of the axis extending from the coating liquid discharge port 116 in the coating liquid discharge direction X and the axis extending from the gas discharge ports 126, 126' in the gas discharge direction. The fine droplets 4 land on the substrate 1 being transported and form a coating film 5. Here, since the gas discharge ports 126, 126' are located away from the imaginary plane A in the discharge direction X of the coating liquid, the gas discharged from the gas discharge ports 126, 126' does not hit the coating liquid discharge nozzle 110 and is not attenuated, and furthermore, the discharged gas does not hit the coating liquid discharge port 116 directly. In other words, drying of the coating liquid at the coating liquid discharge port 116 can be suppressed. At this time, since the gas discharged from the gas discharge ports 126, 126' diffuses as it moves away from the gas discharge ports 126, 126', it is preferable that the distance L1 between the coating liquid discharge port 116 and the collision point B is 2 mm or more so that the gas is not blown directly onto the coating liquid discharge port 116. Since the coating liquid discharge nozzle 110 having the coating liquid discharge port 116 and the gas discharge nozzles 120, 120' having the gas discharge ports 126, 126' are arranged independently of each other, even if the coating liquid spreads from the coating liquid discharge port 116, the coating liquid will not reach the gas discharge ports 126, 126', and the coating liquid will not dry out at the gas discharge ports 126, 126'.

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

In order to eject the coating liquid 2 in a columnar shape from the coating liquid ejection ports 116, it is necessary to eject the coating liquid 2 vigorously from each coating liquid ejection port 116, and the ejection amount can be adjusted appropriately depending on the type and viscosity of the coating liquid 2. As a result of extensive investigations by the inventors, it is preferable to set the average flow speed of the coating liquid 2 in the comb-shaped coating liquid flow path inside the coating liquid ejection nozzle 110 to 2 m/s or more, and it is more preferable to set it to 5 m/s or more in order to stabilize the shape of the columnar coating liquid 3 after ejection, regardless of the type or viscosity of the coating liquid 2.

On the other hand, in order to turn the columnar coating liquid 3 into fine droplets 4, it is necessary to forcefully eject the gas from the gas ejection ports 126, 126'. As a result of extensive investigations by the inventors, it is preferable to set the average flow velocity of the gas in the slit-shaped gas flow path inside the gas ejection nozzles 120, 120' to 100 m/s or more. Furthermore, in anticipation of a case in which the shape of the columnar coating liquid 3 is not stable, such as immediately after the start of ejection of the coating liquid, the gas ejection nozzles 120, 120' may have an evacuation mechanism.

The gas discharge nozzles 120, 120' are installed so that the gas discharge direction can be changed as desired, and the angles θ, θ' (hereinafter referred to as "collision angles θ, θ'") between the discharge direction X of the coating liquid discharged from the coating liquid discharge port 116 and the axis extending in the gas discharge direction from the gas discharge port 126, 126' can be changed as desired. In order to make the droplets 4 atomized at the collision point B fly in the direction of the substrate 1 and land on the substrate 1, the collision angles θ, θ' must be less than 90°. In addition, the collision angles θ, θ' affect the size of the droplets that land on the substrate 1, so they should be changed as appropriate. If the collision angles θ, θ' are increased, the size of the droplets will be small, and if the collision angles θ, θ' are decreased, the size of the droplets can be increased.

In addition, the gas ejection nozzles 120, 120' do not need to be installed symmetrically with respect to the ejection direction X of the coating liquid ejected from the coating liquid ejection port 116, and the gas ejection nozzles 120, 120' may be installed so as to be asymmetrical when viewed from the coating liquid ejection nozzle 110. In other words, the gas ejected from the gas ejection nozzles 120, 120' may each have collision points B, B' with the columnar coating liquid 3, and the distances L2, L2' and the collision angles θ, θ' can be changed as desired.

Please refer to FIG. 5. FIG. 5 is a bottom view of the coating liquid discharge nozzle 110 of FIG. 1, as viewed from the coating liquid discharge port side. The coating liquid discharge port 116 of the coating liquid discharge nozzle 110 is a rectangular opening, and a plurality of coating liquid discharge ports 116 are arranged at a predetermined interval W1 (hereinafter referred to as "arrangement pitch") in the longitudinal direction of the coating liquid discharge nozzle 110, and the total of all the coating liquid discharge ports 116 is the coating liquid discharge width W2. At this time, the width of the coating film that can be formed on the substrate 1 is approximately the same as the coating liquid discharge width W2. The opening width W3 of each coating liquid discharge port 116 is preferably 50 μm or more so that the rate of change in the opening area is small even if processing variations between each discharge port occur by about 5 μm, and the thickness t1 of the coating liquid shim 113 is preferably 50 μm or more so that the rate of change in the opening area is small even if shim thickness unevenness occurs by about 5 μm. The opening area of each coating liquid discharge port 116 may be adjusted as appropriate depending on the viscosity of the coating liquid used and the flow rate of the coating liquid to be discharged, but in order to ensure that the coating liquid discharged from the coating liquid discharge port 116 has a constant flow rate and is discharged 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 more preferably to set the opening area to 20,000 ^{μm 2} or less. In addition, the arrangement pitch W1 of the coating liquid discharge port is preferably 10 mm or less from the viewpoint of coating film uniformity. Furthermore, the coating liquid discharge width W2 is preferably smaller than the substrate width in order to minimize the scattering of the coating liquid outside the system.

Please refer to FIG. 6. FIG. 6 is an exploded perspective view showing the configuration of a coating liquid discharge nozzle 210 according to another embodiment of the coating liquid discharge nozzle. The coating liquid discharge nozzle 210 is composed of coating liquid nozzle blocks 211 and 212. One of the coating liquid nozzle blocks 211 has a coating liquid supply port 214 that supplies the coating liquid to the inside of the coating liquid discharge nozzle 210. The other coating liquid nozzle block 212 has a coating liquid manifold 215 for expanding the coating liquid in the width direction and a coating liquid discharge flow path 217 that communicates with the coating liquid manifold 215, and a coating liquid discharge outlet 216 is formed at the tip of the coating liquid discharge flow path 217. The shape of the coating liquid discharge outlet 216 is not limited to a rectangle, and may be a circle or an ellipse.

Refer to FIG. 7. FIG. 7 is a bottom view of the gas discharge nozzle 120 of FIG. 1, with the tip of the gas discharge nozzle 120 seen 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 the gas discharge width W4. Here, the two-dot chain lines indicated by the symbols 116L and 116R indicate the positions of both ends of the coating liquid discharge width W2 in the coating liquid discharge nozzle 110. The gas discharge width W4 is longer than the coating liquid discharge width W2 in order to make all the columnar coating liquid 3 discharged from each coating liquid discharge port 116 into fine droplets 4. Note that the shape of the gas discharge port 126 is not limited to a single slit continuous across the width as shown in FIG. 3 and FIG. 7, and may be open intermittently in the width direction so as to correspond one-to-one to the coating liquid discharge port 116. When the openings are intermittent, it is preferable that the opening length in the width direction is greater than the width W3 of each coating fluid discharge port 116.

Refer to FIG. 8. FIG. 8 is an exploded perspective view showing the configuration of a gas discharge nozzle 220 according to another embodiment of the gas discharge nozzle. The gas discharge nozzle 220 is composed of gas nozzle blocks 221 and 222. One of the gas nozzle blocks 221 has a gas supply port 224 that supplies gas to the inside of 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 flow path 227 that communicates with the gas manifold 225, and a gas discharge port 226 is formed at the tip of the gas discharge flow path 227. The shape of the gas discharge port 226 is not limited to a rectangle, and may be a circle or an ellipse.

As described above, by using the spray coating device of the present invention, coating liquid can be stably applied without clogging the coating liquid outlet and gas outlet, even when a coating liquid containing solids is discharged.

Next, a coated substrate manufacturing apparatus 10 that manufactures a coated substrate using the coating apparatus 100 of the present invention will be described with reference to FIG. 9. FIG. 9 is a schematic diagram showing an example of a coated substrate manufacturing apparatus 10 of the present invention.

The coated substrate manufacturing apparatus 10 is provided with an unwinding section 11 that unwinds the substrate 1 and a winding section 12 that winds the coated substrate 6. Between the unwinding section 11 and the winding section 12, a coating device 100 for coating the substrate 1 with a coating liquid and a drying device 13 for drying the coating are provided. In addition, in order to prevent the substrate 1 from vibrating due to the gas discharged from the coating device 100 and the distance between the coating device 100 and the substrate 1 from changing over time, a backup roll 14 is provided on the opposite side of the substrate 1 of the coating device 100, which contacts the substrate 1 and supports the substrate 1. At this time, by having the substrate 1 embraced by the backup roll 14, it is possible to prevent the backup roll 14 from rotating due to the transport of the substrate 1, and the substrate 1 from slipping on the backup roll 14 and being scratched. Furthermore, the coating liquid discharge mechanism includes a liquid supply pump 15 for supplying the coating liquid to the coating device 100 and a tank 16 for storing the coating liquid, and the gas discharge mechanism includes 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 adjustment valves 19, 19' that can adjust the pressure of the gas supplied from each gas discharge nozzle. The coating device 100 and the backup roll 14 are surrounded by a booth 20, which has an opening 21 at the bottom and is connected to a waste liquid recovery tank 22.

The booth 20 prevents some of the fine droplets 4 formed by the coating device 100 from scattering around without adhering to the substrate 1. The coating liquid 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 recovery tank 22 through the bottom opening 21. Since the booth 20 and the waste liquid recovery tank 22 come into contact with the coating liquid, it is preferable to select materials according to the coating liquid. For example, when the solvent of the coating liquid is acetone, which is a low-boiling organic solvent, it is preferable to use metal or a resin material with excellent acetone resistance, such as fluororesin.

In the coated substrate manufacturing apparatus 10 shown in FIG. 9, the coating liquid is discharged from the coating device 100 in a vertical downward direction, and the substrate 1 in that section is transported in a horizontal direction; however, this is not limited to the above as long as the coating device 100 is installed so as to be substantially opposite the coating surface of the substrate 1. For example, the coating liquid may be discharged from the coating device 100 in a horizontal direction, and the substrate 1 in that section may be transported in a vertical direction.

Next, the method for producing a substrate with a coating film using the coating device 100 of the present invention will be described again with reference to FIG. 4. The substrate with a coating film is produced by forming a coating film 5 on a substrate 1 using the coating device 100. At this time, since the basis weight of the coating film 5 can be controlled by the flow rate of the coating liquid 2 supplied to the coating liquid discharge nozzle 110, it is preferable to have a means for measuring the basis weight of the formed coating film 5 and adjusting the supply flow rate of the coating liquid 2. In addition, the size of the attached droplets is determined by the flow rate of the gas supplied to the gas discharge nozzles 120 and 120' and the collision angles θ and θ'. If it is desired 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, if 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'.

In addition, immediately after the coating liquid is discharged, the discharge pressure of the coating liquid 2 discharged from the coating liquid discharge port 116 of the coating liquid discharge nozzle 110 is small, and the shape of the columnar coating liquid 3 may not be stable until the discharge pressure increases to a predetermined level. Therefore, it is preferable to retract the gas supply nozzles 120, 120' so that the coating liquid does not scatter at the gas supply nozzles 120, 120' until a stable columnar coating liquid 3 is formed. After that, after the shape of the columnar coating liquid 3 has stabilized, the gas discharge nozzles 120, 120' are brought close to the columnar coating liquid 3, and gas is discharged from the gas discharge ports 126, 126'. As a result, the coating liquid 2 does not adhere to the gas discharge ports 126, 126', and stable coating is possible without blocking the gas discharge ports 126, 126'.

The coating device of the present invention is particularly effective for coating liquids containing solids, such as solutions of inorganic or organic substances or dispersions of inorganic or organic substances in a solvent. The viscosity of the coating liquid may be any viscosity as long as it can be made fine by the collision of the discharged gas, but the lower the viscosity, the finer the droplets that can be formed, and generally a good coating appearance can be obtained by making the viscosity 500 mPa·s or less. It is particularly preferable to make the viscosity 2.0 mPa·s or less.

The effects of the present invention can be particularly achieved when the coating liquid contains an organic solvent as part of the solvent. In particular, the effects are high when the coating liquid contains at least one of the following low-boiling organic solvents having a boiling point of 100°C or less: 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.

There are no particular limitations on the gas or gas components of the outside air used in the present invention, so long as they are suitable for coating, and air, nitrogen gas, etc. can be used. There are no particular limitations on the ambient pressure of the outside air, and it can be an atmospheric pressure environment or a reduced pressure environment. There are also no particular limitations on the temperature of the gas or outside air, but using hot air as the gas promotes the drying of fine droplets in flight. This not only makes it possible to form finer droplets, but also reduces the amount of moisture adhering to the substrate, thereby reducing the drying load in subsequent processes.

The present invention will be described in more detail below with reference to examples. Note that the present invention is not limited to the following examples.

<Coating Fluid>
As the solid content, polyvinylidene fluoride, a fluororesin, was prepared, and as the solvent, acetone (boiling point 56° C.), a low boiling point organic solvent, was prepared. The solid content was mixed to a concentration of 5 wt %, to prepare a coating liquid.

[Example 1]
The coating device 100 of FIG. 1 was mounted on the coating film-coated substrate manufacturing apparatus 10 of FIG. 9 to produce a coating film-coated substrate 6. A coating film was formed on the substrate 1 unwound from the unwinding section 11 using the coating device 100, and the coating film was completely dried in the drying device 13, after which the coating film-coated substrate 6 was wound up in the winding section 12. The wound up coating film-coated substrate 6 was then removed, and the presence or absence of droplets attached and the coating appearance were evaluated by visual and microscope observation. The coating conditions in the coating device 100 were as follows: the distance from the imaginary plane A passing through the coating liquid discharge port 116 to the gas discharge ports 126, 126' was 7.5 mm, the distance L1 between the coating liquid discharge port 116 and the collision point B was 10 mm, the distances L2, L2' between the gas discharge ports 126, 126' and the collision point B were 5 mm, and the collision angles θ, θ' were 60° (see FIG. 4). The coating liquid discharge nozzle 110 had a coating liquid discharge width W2 of 210.1 mm, an opening width W3 of the coating liquid discharge port of 100 μm, a coating liquid shim thickness t1 of 100 μm, and an arrangement pitch W1 of the coating liquid discharge ports of 7.5 mm. In this case, the number of coating liquid discharge ports 116 was 29 (see FIG. 5). The gas discharge nozzles 120 and 120' had a gas discharge width W4 of 250 mm and a gas shim thickness of 50 μm (see FIG. 7). As a coating procedure, the substrate 1 was transported at a speed of 50 m/min, the coating liquid was discharged from the coating liquid 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]
Coating was carried out on the substrate 1 under the same conditions as in Example 1, except that the collision angles θ and θ′ were set to 30°.

[Example 3]
Coating was carried out on the substrate 1 under the same conditions as in Example 1, except that the distance L1 between the coating liquid discharge port 116 and the collision point B was set to 2 mm, and the collision angles θ and θ′ were set to 80°.

[Comparative Example 1]
Coating was performed on the substrate 1 under the same conditions as in Example 1, except that the distance L1 between the coating liquid discharge port 116 and the collision point B was set to 0.5 mm. In Comparative Example 1, in relation to the distance L1, the gas discharge ports 126, 126' are located on the opposite side to the substrate 1 side from the imaginary plane A. In other words, the gas discharge ports 126, 126' according to Comparative Example 1 are located on the coating liquid discharge nozzle 110 side from the imaginary plane A.

[Comparative Example 2]
Coating was carried out on the substrate 1 under the same conditions as in Example 1, except that the collision angles θ and θ′ were set to 90°.

[Comparative Example 3]
A coating was carried out on a substrate 1 using a conventional integrated two-fluid nozzle 300 shown in FIG. 10. The integrated two-fluid nozzle 300 has a longitudinal direction perpendicular to the conveying direction Y of the substrate 1, i.e., the width direction of the substrate 1 (perpendicular to the paper surface), and is installed at a certain distance from the substrate 1 so as to face the substrate 1. The integrated two-fluid nozzle 300 is composed of outer die blocks 301, 301' and inner die blocks 302, 302'. The coating liquid is supplied to a coating liquid pocket 303 and discharged from a coating liquid discharge port 304, and the gas is supplied to gas pockets 305, 305' and discharged from gas discharge ports 306, 306'. The gas discharge ports 306, 306' are provided so as to sandwich the coating liquid discharge port 304 when observed from the discharge direction of the coating liquid. The coating liquid discharge port 304 and the gas discharge ports 306, 306' are on the same plane. Using this integrated two-fluid nozzle 300, coating was carried out on the substrate 1 in the same manner as in Example 1.

<Evaluation method>
In the above examples and comparative examples, coating was performed continuously for 30 minutes. The coating state was evaluated using the substrate 6 with the coating film wound up by the winding section 12. The evaluation results are shown in Tables 1 and 2. The droplet adhesion rate on the substrate was used as the criterion for determining whether or not droplets could be attached in the tables. The droplet adhesion rate on the substrate was derived by measuring the basis weight of the substrate with the coating film and the substrate before coating, respectively, calculating 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 liquid supplied to the coating liquid discharge nozzle. The evaluation of whether or not droplets could be attached was judged as "○" if it was 30% or more of the total solid content, and "×" if it was less than 30%. The average particle size of the droplets was measured using a laser diffraction particle distribution meter (FLD-319A, manufactured by Seika Digital Image Co., Ltd.) for the droplets flying just before they were attached to the substrate. The average particle size shown here refers to the Sauter mean diameter. In addition, in order to check the blocking state of the coating liquid discharge port 116 during the coating operation, a pressure gauge (not shown) was installed so as to communicate with the coating liquid manifold 115, and the pressure in the coating liquid manifold was measured 15 minutes and 30 minutes after the start of coating. In terms of the coating appearance, the coating missing refers to a coating missing area in which coating is not performed in a streak-like manner occurring in the substrate conveying direction, and the coating unevenness refers to a linear appearance unevenness occurring in the substrate conveying direction, and represents coating unevenness caused by different liquid adhesion rates on the substrate. In addition, for the evaluation of coating liquid discharge port blocking and gas discharge port blocking, the tip of each discharge nozzle was observed after 30 minutes of continuous coating, and if even partial blocking was observed, it was judged to be blocked. In addition, the appearance of the coating film was good in all examples and comparative examples immediately after the start of coating, and the pressure in the coating liquid manifold was 0.1 MPa.

[Comparison between Example 1 and Comparative Example 3]
In the conventional integrated two-fluid nozzle 300 described in Comparative Example 3, solids of the coating liquid were precipitated at both the coating liquid discharge port 304 and the gas discharge ports 306, 306' 30 minutes after the start of coating, and clogging was confirmed at each discharge port. In addition, due to this, streaky coating missing areas and linear coating unevenness were observed on the substrate after coating. Furthermore, the pressure of the coating liquid manifold rose to 0.2 MPa 15 minutes after the start of coating. When the coating liquid discharge port is clogged, the opening area of the coating liquid discharge port becomes smaller, so if a fixed amount of coating liquid is continued to be sent by the liquid feed pump, the pressure inside the coating liquid manifold increases. In other words, it was confirmed that a part of the coating liquid discharge port 304 was clogged in a short time from the start of coating to 15 minutes. On the other hand, in Example 1, even 30 minutes after the start of coating, the pressure inside the coating liquid manifold did not increase, and no blockage of the coating liquid outlet 116 and the gas outlets 126, 126' was observed, and a coating film 5 with a good coating appearance was formed.

[Comparison between Example 1 and Example 2]
In Example 2, it was confirmed that by reducing the collision angles θ and θ', the average particle size of the droplets became larger than that of Example 1. That is, it was confirmed that by changing the collision angles θ and θ', the force of collision with the columnar coating liquid 3 could be controlled to change the average particle size of the droplets to a desired size. Furthermore, in both the cases of Examples 1 and 2, even 30 minutes after the start of coating, the pressure inside the coating liquid manifold did not increase, and no blockage of the coating liquid discharge port 116 and the gas discharge ports 126 and 126' was observed, and a coating film 5 with a good coating appearance could be formed.

[Comparison between Example 1 and Example 3]
In Example 3, the distance L1 between the coating liquid discharge port and the collision point was set to 2 mm, and the collision angles θ and θ' were set to 80° so that the gas discharge ports 126 and 126' were located away from the imaginary surface A toward the substrate 1. It was confirmed that the average particle size of the droplets was reduced by increasing the collision angles θ and θ' compared to Example 1. Furthermore, in both the cases of Examples 1 and 3, the pressure inside the coating liquid manifold did not increase even 30 minutes after the start of coating, and no blockage of the coating liquid discharge port 116 and the gas discharge ports 126 and 126' was observed, and a coating film 5 with a good coating appearance could be formed.

[Comparison between Example 1 and Comparative Example 1]
In Comparative Example 1, the gas discharge ports 126, 126' are located on the opposite side to the substrate 1 side from the imaginary plane A. The gas discharged from the gas discharge ports 126, 126' hits the coating liquid discharge nozzle 110 and does not hit the columnar coating liquid 3, and the fine droplets 4 were not formed. Thereafter, in order to hit the gas discharged from the gas discharge ports 126, 126' against the columnar coating liquid 3, the collision angles θ, θ' were adjusted with the positions of the gas discharge ports 126, 126' fixed, but in the range of L2≦10 mm, the fine droplets 4 could not be formed, and in the range of L2>10 mm, the gas colliding with the columnar coating liquid 3 was attenuated, and the fine droplets 4 could not be formed.

[Comparison between Example 1 and Comparative Example 2]
In Comparative Example 2, the collision angles θ and θ' were 90°. Therefore, the droplets 4 atomized at the collision point B did not move toward the substrate 1, and as a result, the droplet adhesion rate significantly decreased to 10%. In addition, some of the minute droplets 4 that moved toward the coating liquid discharge port 116 precipitated at the coating liquid discharge port 116, causing a portion of the coating liquid discharge port 116 to become clogged.

The present invention can be applied to, but is not limited to, a coating device that forms a coating film on a substrate film such as resin, paper, thin metal film, or cloth, and a manufacturing device and manufacturing method for a substrate with a coating film that is equipped with the coating device.

Reference Signs List 1 Substrate 2 Coating liquid 3 Columnar coating liquid 4 Fine droplets 5 Coating film 6 Substrate with coated film 10 Apparatus for manufacturing substrate with coated film 11 Unwinding section 12 Winding section 13 Drying device 14 Backup roll 15 Liquid delivery pump 16 Tank 17 Pressurized gas source 18 Branch pipes 19, 19' Pressure regulating valve 20 Booth 21 Bottom opening 22 Waste liquid recovery tank 100 Coating device 110 Coating liquid discharge nozzle 111, 112 Coating liquid nozzle block 113 Coating liquid shim 114 Coating liquid supply port 115 Coating liquid manifold 116 Coating liquid 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 nozzles 211, 212 Coating fluid nozzle block 214 Coating fluid supply port 215 Coating fluid manifold 216 Coating fluid discharge port 217 Coating fluid discharge flow path 220 Gas discharge nozzles 221, 222 Gas nozzle block 224 Gas supply port 225 Gas manifold 226 Gas discharge port 227 Gas discharge flow path 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 planes B, B' Collision point L1 Distance L2, L2' between coating fluid discharge port and collision point Distance t1 between gas discharge port and collision point Thickness W1 of coating fluid shim Array pitch W2 of coating fluid discharge ports Coating fluid discharge width W3 Opening width W4 of each coating fluid discharge port Gas discharge width X Coating fluid discharge direction Y Substrate transport direction θ, θ' Collision angle

Claims (7)

A coating device that applies a coating liquid in droplet form to a traveling substrate,
a coating liquid discharge nozzle having a plurality of coating liquid discharge ports arranged in a width direction of the substrate;
at least two gas ejection nozzles for blowing gas onto the plurality of columnar coating liquids ejected from the coating liquid ejection port;
The two gas discharge nozzles are:
When observed from the direction of discharging the coating liquid, each gas discharge port sandwiches a row of the plurality of coating liquid discharge ports,
the gas discharge port is provided so as to be located away from a virtual plane that passes through the coating liquid discharge port and is perpendicular to a discharge direction of the coating liquid, toward the substrate;
and when observed from the width direction of the substrate, an angle between an axis extending in a gas discharge direction from the gas discharge port and an axis extending in a coating liquid discharge direction from the coating liquid discharge port is less than 90°.
Coating equipment. The coating device of claim 1, wherein the gas discharge nozzle is configured to be capable of changing the direction in which the gas is discharged from the gas discharge port as observed from the width direction of the substrate. The coating device of claim 1 or 2, wherein when the coating device is observed from the width direction of the substrate, the distance from the intersection of an axis extending from the coating liquid outlet in the coating liquid outlet direction and an axis extending from the gas outlet in the gas outlet direction to the coating liquid outlet is 2 mm or more. A coating liquid is discharged from a plurality of coating liquid discharge ports arranged in a width direction of the substrate toward the traveling substrate;
blowing gas toward the coating liquid at a position away from the coating liquid discharge port toward the substrate from a direction that is symmetrical with respect to the discharged coating liquid and forms an angle of less than 90° with the discharge direction of the coating liquid when observed from the width direction of the traveling substrate;
The droplets of the coating liquid are applied to a substrate.
A method for producing a substrate with a coating. The method for producing a substrate with a coating film according to claim 4, wherein the distance from the position where the gas is sprayed in the coating liquid to the coating liquid discharge port is 2 mm or more. The method for producing a substrate with a coating film according to claim 4 or 5, wherein the coating liquid contains solids. The method for producing a substrate with a coating film according to claim 4 or 5, wherein the solvent of the coating liquid is an organic solvent.

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