JP2009028638A - Coating method and coating apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a three-reverse roll coating method and a coating apparatus expanding a coating speed limit in the three-reverse roll coating and allowing high-speed thin-film coating. <P>SOLUTION: Coating liquid discharged from a coating liquid discharge port 6b is discharged toward the central shaft 2b of an applicator roll 2, as shown by an arrow E, and the coating liquid in a liquid dam 5 is firmly attached to a part for starting feeding of coating liquid 2c of the applicator roll 2 by the discharged coating liquid. Accordingly, air involving is suppressed at the part for starting feeding of coating liquid 2c, the coating liquid 10 is continuously attached on the periphery 2a of the applicator roll 2 from the part for starting feeding of coating liquid 2c to a measuring part 19, with air entrainment suppressed following rotation of the applicator roll 2. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an application method and an application apparatus for applying various paints to a flexible support such as a plastic film, paper, adhesive paper, metal foil or the like (hereinafter referred to as a web). The coating liquid is supplied from a gap between a rotating metering roll and an applicator roll that rotates in the direction opposite to the rotation direction of the metering roll from a liquid dam that stores the liquid, and a coating liquid layer having a predetermined thickness is formed on the surface of the applicator roll. The coating liquid layer is rolled onto the web on the backup roll that rotates in the direction opposite to the rotation direction of the applicator roll while being pressed against the applicator roll through the web to apply the coating liquid onto the web. The present invention relates to a coating method and a coating apparatus using so-called three reverse rolls.

Conventionally, as a reverse roll coater, for example, a three reverse roll coater as shown in FIG. 13 is known. (For example, refer to Patent Document 1) This coating apparatus includes an applicator roll 2, a backup roll 3 for web travel provided above the roll with a gap for web 4 travel, and a lower side of the applicator roll 2. The metering roll 1 provided with a gap for adjusting the coating thickness is provided, and the applicator roll 2 and the liquid dam 5 of the coating liquid 10 provided behind the metering roll 1 are provided. The liquid dam 5 is composed of a back plate 5a, side deckels 5b and a bottom plate 5c provided on the left and right sides of the back plate 5a, and is provided along the width direction (axial direction) of the applicator roll 2. The liquid 10 is stored.
In this coating apparatus, when the applicator roll 2 and the metering roll 1 rotate in the direction of the arrow, the coating liquid 10 in the liquid dam 5 is discharged from the liquid dam 5 through the gap between the applicator roll 2 and the metering roll 1, A coating liquid layer 101 having a thickness is formed on the peripheral surface 2 a of the applicator roll 2. Then, the coating liquid layer 101 on the peripheral surface 2 a of the applicator roll 2 is rolled onto the surface of the web 4 that travels by the rotation of the backup roll 3 in the direction of the arrow to form the coating liquid layer 102. As a result, the coating solution 10 is applied to the surface of the web 4 with a uniform thickness.
Such a coating apparatus using three reverse rolls has a relatively simple configuration and can easily form a coating liquid layer 102 having a uniform thickness on the web 4. Therefore, the coating speed is 100 m. There was a problem that it could be used only at a low coating speed of less than 1 minute. One reason why the coating speed becomes slow is that an air entrainment phenomenon occurs in which air is taken in at the coating liquid supply start portion (dynamic liquid contact line) 2b where the coating liquid is first supplied to the applicator roll 2. is there.

In the liquid dam type three reverse roll coating method, the liquid dam 5 for storing the coating liquid 10 is used. However, in the case of a low viscosity coating liquid, the coating liquid easily leaks from the gap where the applicator roll 2 and the liquid dam 5 are in contact with each other. Therefore, it is common to apply with a relatively high viscosity coating solution. Therefore, since the coating is performed with a high viscosity liquid having low liquid fluidity, the coating liquid surface 10a of the coating liquid supply starting portion (dynamic tangential line) 2a of the applicator roll 2 is easily drawn in the rotating direction of the applicator roll 2, and high speed. It becomes easy to cause an air entrainment phenomenon. When the entrained air 10b reaches the calibration unit 19 of the applicator roll 2 and the metering roll 1 by such an air entrainment phenomenon, the coating liquid layer 101 formed on the peripheral surface 2a of the applicator roller 2 is formed as shown in FIG. A so-called liquid breakage phenomenon that does not become a continuous layer but an intermittent layer occurs, and this liquid breakage phenomenon is transferred to the web 4, thereby forming an intermittent liquid drop coating liquid layer 102 on the web 4. It will be. Such an air entrainment phenomenon occurs more remarkably when a Newtonian coating liquid is used as a liquid characteristic, and is a liquid with a strong shear thinning that is sheared by rotation of the applicator roll 2 and is reduced in viscosity. However, although the coating speed limit is slightly increased, an air entrainment phenomenon occurs and a liquid breakage phenomenon is likely to occur.
As shown in FIG. 15, as a high speed coating method for reverse roll coating, it is known that a coating liquid is directly supplied from the offset die 14 to the peripheral surface 2a of the applicator roll 2 to form a coating liquid layer 101 having a predetermined thickness. It has been. (For example, see Patent Document 2)
JP-A-6-339651 JP-A-10-128204

However, in the thing of patent document 2, since a free surface is not formed in the surface of the coating liquid 10 of the coating liquid supply start part 2b of the applicator roll 2, it is hard to generate | occur | produce an air entrainment phenomenon and does not raise | generate a liquid breakage at high speed. In order to form a coating liquid layer 101 having a predetermined thickness on the peripheral surface 2a of the applicator roll 2, a coating gap K between the coating liquid discharge port 14a at the tip of the die 14 and the peripheral surface 10a of the applicator roll. As a result, the application gap K is liable to cause coating streaks or liquid breakage due to clogging of foreign matter or the like, which is cheap.
The present invention has been made in consideration of the above circumstances, and an object of the present invention is to provide a three reverse roll coating method and a coating apparatus capable of expanding the coating speed limit in three reverse roll coating and capable of high-speed thin film coating. And

In order to solve the above-mentioned problem, the invention according to claim 1 is provided between a rotating metering roll and an applicator roll that rotates in a direction opposite to the rotation direction of the metering roll from a liquid dam that stores the coating liquid. The coating liquid layer having a predetermined thickness is formed on the surface of the applicator roll by supplying from the gap between the web and the web on the backup roll that rotates in the reverse direction to the rotation direction of the applicator roll while being pressed against the applicator roll through the web. In the coating method in which the coating liquid layer is tumbled to apply the coating liquid onto the web, a nozzle feeder for supplying the coating liquid to the applicator roll is provided in the liquid dam, and the coating liquid discharge of the nozzle feeder is provided. The application liquid is supplied from the outlet to the supply start section of the applicator roll, and the applicator roll And forming a coating liquid layer having a predetermined thickness on the surface.
The invention according to claim 2 is characterized in that in the coating method according to claim 1, coating is performed at a coating speed of 100 m / min or more for coating the web with the coating liquid.
Further, the invention of claim 3 is the coating method according to claim 1 or 2, wherein the nozzle feeder is arranged on the peripheral surface of the applicator roll from the coating liquid discharge port toward the central axis of the applicator roll. It discharges to a supply start part, It is characterized by the above-mentioned.

The invention of claim 4 is the coating method according to any one of claims 1 to 3, wherein the coating liquid discharge port of the nozzle feeder is applied to the web from the supply start portion of the applicator roll. The coating liquid is discharged within a range of 1 to 12 times the thickness of the coating liquid layer to be applied and discharged from the coating liquid discharge port to the supply start portion of the applicator roll.
The invention according to claim 5 is the coating method according to any one of claims 1 to 4, wherein the coating liquid is applied from the coating liquid discharge port of the nozzle feeder to the supply start portion of the applicator roll. And discharging.
The invention according to claim 6 is the coating method according to any one of claims 1 to 5, wherein the amount of coating liquid discharged from the coating liquid discharge port of the nozzle feeder to the applicator roll is applied to the web. It is characterized in that the coating liquid is discharged from the coating liquid discharge port by setting it to be equal to or more than the coating amount for applying the liquid.
The invention according to claim 7 is the coating method according to any one of claims 1 to 6, wherein the liquid level in the liquid dam is the same height as the coating liquid discharge port of the nozzle feeder. It is characterized by adjusting.
Further, the invention of claim 8 is directed to a liquid dam for storing a coating liquid, a rotating applicator roll to which the coating liquid is supplied from the liquid dam, and a rotating direction of the applicator roll to be reversed. A metering roll that is supplied from a gap with the applicator roll to form a coating liquid layer having a predetermined thickness on the surface of the applicator roll, and rotates in a direction opposite to the rotation direction of the applicator roll while being pressed against the applicator roll via a web. Then, in the coating apparatus for coating the web with a coating liquid provided with a backup roll for transferring the coating liquid layer onto the web, the coating liquid is applied to the coating liquid supply start section of the applicator roll in the liquid dam. A nozzle feeder having a coating liquid discharge port for discharging is provided.

Further, the invention of claim 9 is the coating apparatus according to claim 8, wherein the coating liquid discharge port of the nozzle feeder is disposed toward the central axis of the applicator roll, and the applicator roll extends from the coating liquid discharge port. The coating liquid is discharged toward the central axis.
The invention according to claim 10 is the coating apparatus according to claim 8 or 9, wherein the nozzle feeder is provided with variable means for varying the distance between the applicator roll and the coating liquid discharge port of the nozzle feeder within a range of 0 to 1 mm. It is characterized by being provided in.
The invention of claim 11 is the coating apparatus according to any one of claims 8 to 10, wherein the coating liquid is applied to the web by the amount of the coating liquid discharged from the coating liquid discharge port of the nozzle feeder. It has the coating liquid discharge port set to the range of 1 to 2 times the coating amount to perform.
According to a twelfth aspect of the present invention, in the coating apparatus according to any one of the eighth to eleventh aspects, the liquid level in the liquid dam is the same as the height of the coating liquid discharge port of the nozzle feeder. As described above, the liquid level height adjusting means is provided.
The invention of claim 13 is the coating apparatus according to any one of claims 8 to 12, wherein the nozzle feeder prevents the coating liquid in the liquid dam from flowing out in the axial direction of the applicator roll. It is mounted on the side deckle and a coating liquid outflow prevention plate is disposed between the side deckle and the nozzle feeder.

According to the present invention, the nozzle feeder for supplying the application liquid to the applicator roll is provided in the liquid dam, and the application liquid is supplied from the application liquid discharge port of the nozzle feeder to the supply start portion of the applicator roll. By forming a coating liquid layer having a predetermined thickness on the peripheral surface, a coating speed limit in three reverse roll coating can be expanded, and a three reverse roll coating method capable of high-speed thin film coating can be provided.
Further, according to the present invention, by disposing a nozzle feeder having a coating liquid discharge port for discharging a coating liquid at a coating liquid supply start portion of the applicator roll in the liquid dam, in the three reverse roll coating It is possible to provide a three reverse roll coating apparatus capable of expanding the coating speed limit and performing high-speed thin film coating.

In order to increase the coating speed limit using three reverse rolls, the present inventors have studied the air entrainment phenomenon that occurs when performing high-speed coating in the liquid dam type. With the high-speed rotation of the applicator roll, the coating liquid surface in the liquid dam becomes a free surface, so that air is entrained between the coating liquid surface and the applicator roll peripheral surface, and the coating liquid supply start unit descends. As a result of studying to suppress the descent of the coating liquid supply start part, if the liquid pressure is applied to the coating liquid surface of the coating liquid supply start part and the adhesion between the coating liquid surface and the applicator roll peripheral surface is increased It has been found that the coating liquid supply start part can be prevented from descending.
As a result of further investigation based on this discovery, a nozzle feeder that discharges the coating liquid toward the coating liquid supply start part of the applicator roll is provided in the liquid dam, and the coating liquid is supplied from the nozzle feeder to the coating liquid of the applicator roll. It has been found that if it is discharged to the start portion, the adhesion between the coating liquid surface and the peripheral surface of the applicator roll is improved and the air entrainment phenomenon can be suppressed, and the invention as described below has been completed. Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

1 and 2 are diagrams showing a schematic configuration of a coating apparatus according to an embodiment of the present invention. The coating apparatus according to the present embodiment includes a liquid dam 5 that stores the coating liquid 10, and an applicator roll 2 that rotates in the direction of arrow A about the central axis 2 b to which the coating liquid 10 is supplied from the liquid dam 5. ing. Further, below the applicator roll 2, the applicator roll 2 rotates about the central axis 1 a in the direction B opposite to the rotation direction A, and the coating solution 10 is supplied from a gap (calibration unit) 19 with the applicator roll 2. A metering roll 1 for forming a coating liquid layer 101 having a predetermined thickness on the peripheral surface 2 a of the applicator roll 2 is provided. Further, above the applicator roll 2, the web 4 is rotated around the central axis 3 a in the direction C opposite to the rotation direction A of the applicator roll while being pressed against the applicator roll 2 via the web 4, and the web 4 is rotated in the direction of arrow D. And a backup roll 3 that forms the coating liquid layer 102 by rolling the coating liquid layer 101 on the web 4.
The liquid dam 5 has a side plate having a back plate 5a, side end walls 5b1 slidably contacting the peripheral surface 2a of the applicator roll 2 and side end walls 5b2 slidably contacting the peripheral surface 1a of the metering roll 1 on both sides of the back plate 5a. It has a kel 5b (see FIG. 2). Further, the liquid dam 5 has a bottom plate 5 c having an end wall 5 c 1 that is in sliding contact with the peripheral surface 1 a of the metering roll 1, and the coating liquid 10 can be stored in the liquid dam 5. And the liquid dam 5 is attached along the width direction (axial direction) of the applicator roll 2, the side of the liquid dam 5 is opened, and the peripheral surface 2a of the applicator roll 2 and the metering roll 1 are opened from the opening 5d. The coating liquid 10 can be supplied to the peripheral surface 1a.

Further, in the liquid dam 5, a nozzle feeder 6 that discharges the coating liquid 10 from the coating liquid discharge port 6 b at the tip of the lip 6 a is disposed in the coating liquid supply start part 2 c of the applicator roll 2. The nozzle feeder 6 is formed by combining an upper part 6c and a lower part 6d, and is formed in an intermediate part between the upper part 6c and the lower part 6d in parallel with the axis of the applicator roll 2, and is applied in the width direction of the applicator roll 2 And a slot 8 that communicates with the manifold 7 and that extends to the coating liquid discharge port 6b. The coating liquid discharge port 6 b is opened over the entire length of the coating width of the applicator roll 2, and the coating liquid 10 supplied into the manifold 7 passes through the slot 8 from the coating liquid discharge port 6 b to the periphery of the applicator roll 2. It is discharged to the coating liquid supply start part 2c on the surface 2a.
In this case, the coating liquid discharged from the coating liquid discharge port 6b is discharged toward the central axis 2b of the applicator roll 2 as indicated by an arrow E, and the coating liquid in the liquid dam 5 is discharged by the discharged coating liquid. The applicator roll 2 is firmly attached to the coating liquid supply start portion 2c. Therefore, the entrainment of air in the coating liquid supply start unit 2c is suppressed, and the entrainment of air is suppressed as the applicator roll 2 rotates, so that the coating liquid 10 is applied from the coating liquid supply start unit 2c to the calibration unit 19 in the applicator roll 2. Will be continuously attached to the peripheral surface 2a.
Thus, in order for the coating liquid to be supplied to the coating liquid supply starting unit 2c in a state where air entrainment is suppressed in the coating liquid supply starting unit 2c, the coating liquid discharged from the coating liquid discharge port 6b is applied. It is necessary to apply a liquid pressure to the coating liquid in the vicinity of the liquid supply start portion 2c. Such liquid pressure is determined by the application liquid discharge direction and discharge amount from the application liquid discharge port 6 b of the nozzle feeder 6, the position where the application liquid discharge port 6 b is disposed, and the supply of the application liquid from the application liquid discharge port 6 b and the applicator roll 2. It is influenced by the distance from the start part 2c and the like.

  The discharge direction of the coating liquid from the coating liquid discharge port 6b of the nozzle feeder 6 will be described. When the discharge direction of the coating liquid deviates from the central axis 2b of the applicator roll 2 in the vertical direction, the coating liquid is discharged from the coating liquid discharge port 6b. The liquid pressure due to the force is likely to be reduced at the coating liquid supply start unit 2c, and it becomes difficult to suppress the air entrainment well, so the discharge direction of the coating liquid is set to be directed toward the central axis 2b of the applicator roll 2. If this is the case, it is possible to apply the liquid pressure to the coating liquid supply start portion 2c most effectively, which is preferable. In this case, the front end surface 6a1 of the lip portion 6a of the nozzle feeder 6 that forms the coating liquid discharge port 6b is formed substantially parallel to the tangent to the coating liquid supply start unit 2c, and the coating liquid discharge port 6b is appropriately connected. It is possible to set the applicator roll 2 toward the central axis 2b. When the tip surface 6a1 is formed so as to be inclined up and down with respect to the tangent to the coating liquid supply start portion 2c, the coating liquid runs on the lip portion 6a of the nozzle feeder 6 and the liquid pressure is insufficient. Air entrainment is likely to occur.

The interval F between the coating liquid discharge port 6b of the nozzle feeder 6 and the coating liquid supply start part 2c of the applicator roll 2 is in the range of 1 to 12 times the thickness d of the coating liquid layer 102 formed on the web 4. If this interval F is small, clogging of foreign matters or the like is likely to occur and air entrainment easily occurs. Conversely, if it is 12 times or more, the liquid pressure of the coating liquid from the coating liquid discharge port 6b becomes small. It becomes easy to invite air companion. In the coating apparatus of the present embodiment, in order to finely adjust the interval, as shown in FIG. 3, a variable means (not shown) that changes the nozzle feeder 6 by about 0 to 1 mm in the arrow J direction is provided. By finely adjusting the interval F of the nozzle feeder 6 with this variable means, the optimum coating liquid layer 102 can be formed on the web 4. The nozzle feeder 6 is movable about 200 mm to the position of the two-dot chain line in order to clean the lip portion 6a.
As described above, since the nozzle feeder 6 is slightly movable back and forth, a gap is formed between the nozzle feeder 6 and the side deckle 5b, and the coating liquid may leak from this gap. In order to prevent this, as shown in FIGS. 2 and 3, in the present embodiment, a coating liquid outflow prevention plate 13 made of a rubber material or the like is attached on the side deckle 5b. This point will be described in detail in Examples.

  In addition, the nozzle feeder 6 is mounted at a position where the coating liquid discharge port 6b of the nozzle feeder 6 is flush with the height of the liquid surface 10a of the coating liquid 10 in the liquid dam 5, and the center of the coating liquid discharge port 6b and the applicator roll 2 The nozzle feeder 6 may be inclined so that the intersection angle (nozzle feeder inclination angle) θ between the center of the shaft 2b and a line (horizontal line) parallel to the liquid surface 10a of the coating liquid 10 is 30 to 40 degrees. desirable. When the coating liquid discharge port 6b of the nozzle feeder 6 is lower than the liquid surface height of the coating liquid 10 in the liquid dam 5, a vortex is generated above the lip portion 6a of the nozzle feeder 6 immersed in the coating liquid, Air entrainment is invited from there, and the liquid runs out. On the other hand, when the coating liquid discharge port 6b of the nozzle feeder 6 is located at a position higher than the liquid level of the coating liquid 10 in the liquid dam 5, the coating liquid supply start portion 2c of the applicator roll 2 is located below, and the coating liquid The coating liquid in the vicinity of the supply start part 2c becomes a free surface, and air entrainment is easily caused. These points will be described in detail based on examples.

Thus, it is preferable that the coating liquid discharge port 6 b of the nozzle feeder 6 has the same height as the liquid surface of the coating liquid 10 in the liquid dam 5. Therefore, in order to maintain such a state, in the present embodiment, the amount of coating liquid to be replenished in the liquid dam 5 is controlled so that the liquid level of the coating liquid in the liquid dam 5 is the same height. is doing. That is, the level of the coating liquid is detected by a liquid level detection means such as a level sensor or a float sensor, and the amount of coating liquid to be replenished in the liquid dam 5 is controlled based on this detection signal, When the liquid dam is replenished into the liquid dam above the predetermined liquid level, the excess coating liquid overflows from the liquid dam 5 so that the liquid level of the coating liquid 10 in the liquid dam 5 is always a constant height. To be adjusted.
As described above, the nozzle feeder 6 is disposed in the liquid dam 5, and the coating liquid is discharged from the coating liquid discharge port 6b of the nozzle feeder 6 toward the coating liquid supply start portion 2c of the applicator roll 2. Even when coating is performed at a high speed, air entrainment at the coating liquid supply start unit 2 c is suppressed, and a continuous coating liquid layer 102 without liquid breakage can be formed on the web 4.

Next, specific conditions and the like will be described based on examples.
[Example 1]
A coating liquid is formed on the peripheral surface of the applicator roll by using the coating apparatus according to the embodiment shown in FIGS. 1 to 3 and forming a coating liquid layer on the web under the following coating conditions, nozzle feeder conditions, and coating liquid conditions. The limit coating speed at which the liquid breakage of the layer occurred was evaluated.
<Application conditions>
-Coating liquid adhesion amount on the web: 25 g / m ² (coating liquid layer thickness: 25 μm)
・ Application width: 240 mm
-Liquid level height: 193mm (Nozzle feeder coating liquid discharge port height)
・ Applicator roll diameter: Φ200mm
<Nozzle feeder conditions>
・ Nozzle feeder tilt angle θ: 35 degrees ・ Nozzle feeder slot gap G: 500 μm
・ Distance between nozzle feeder and applicator roll d: 150 μm
・ Nozzle feeder discharge liquid flow rate: 900 g / min (discharge width: 240 mm)
Coating solution conditions (1)
・ Coating liquid: Acrylic emulsion paste ・ Viscosity: 350 mPa · s (Shear rate: 3000 s ⁻¹ )
Coating solution conditions (2)
・ Coating liquid: Acrylic emulsion paste ・ Viscosity: 500 mPa · s (Shear rate: 3000 s ⁻¹ )
Coating solution conditions (3)
-Coating solution: PVA318 aqueous solution (Kuraray Co., Ltd.)
Viscosity: 30 mPa · s (B-type viscometer No. 2)
Coating solution conditions (4)
-Coating solution: PVA318 aqueous solution (Kuraray Co., Ltd.)
Viscosity: 50 mPa · s (B-type viscometer No. 2)
FIG. 4 shows the result of the liquid shortage limit coating speed when the coating liquid under each coating liquid condition is used. From this result, even in a low-viscosity coating liquid (coating liquid conditions (3) and (4)), no liquid breakage occurs even at a high coating speed of 145 m / min or more and 100 m / min or more, and a good coating liquid layer is obtained. It is clear that it is formed. Furthermore, when a high-viscosity coating liquid (coating liquid conditions (1) and (2)) is used, the coating speed can be further increased, and the productivity is improved.

[Example 2]
Using the coating apparatus of the above-described embodiment shown in FIGS. 1 to 3, a coating liquid layer is formed on the web under the following coating conditions and nozzle feeder conditions, and the coating liquid layer formed on the peripheral surface of the applicator roll is broken. Evaluation was made on the limit coating speed at which occurrence occurred. The evaluation method evaluated the effect as a speed-up rate as compared with the limit coating speed of Comparative Example 1.
<Application conditions>
・ Coating liquid: Acrylic emulsion paste ・ Viscosity: 500 mPa · s (Shear rate: 3000 s ⁻¹ )
-Coating liquid adhesion amount on the web: 25 g / m ² (coating liquid layer thickness: 25 μm)
・ Application width: 240 mm
・ Liquid surface height: 193 mm (nozzle feeder coating liquid discharge port height)
・ Applicator roll diameter: Φ200mm
<Nozzle feeder conditions>
・ Nozzle feeder tilt angle θ: 35 degrees ・ Nozzle feeder slot gap G: 500 μm
Condition (1)
・ Distance between nozzle feeder and applicator roll d: 150 μm
・ Nozzle feeder discharge liquid flow rate: 800 g / min (discharge width: 240 mm)
Condition (2)
・ Distance between nozzle feeder and applicator roll d: 150 μm
・ Nozzle feeder discharge liquid flow rate: 900 g / min (discharge width: 240 mm)

[Comparative Example 1]
The coating conditions were the same as in Example 2, and the coating evaluation was performed as a normal liquid dam type three reverse roll coating method (see FIG. 13) without installing a nozzle feeder.
Next, the results of Example 2 and Comparative Example 1 are shown in FIG. From this result, it is clear that the limit coating speed of Example 2 according to the present invention is greatly increased compared to that of Comparative Example 1 in which no nozzle feeder is used. Further, when the nozzle feeder discharge liquid flow rate indicated by the condition (2) is large, the limit coating speed is higher than that indicated by the condition (1).

[Example 3]
Using the coating apparatus of the embodiment shown in FIGS. 1 to 3, a coating liquid layer is formed on the web under the following coating conditions and nozzle feeder conditions, and coating defects in the coating liquid layer formed on the peripheral surface of the applicator roll The presence / absence of occurrence of (coating streaks, running out of liquid, etc.) was evaluated.
<Application conditions>
・ Coating liquid: Acrylic emulsion paste ・ Viscosity: 500 mPa · s (Shear rate: 3000 s ⁻¹ )
-Coating liquid adhesion amount on the web: 25 g / m ² (coating liquid layer thickness: 25 μm)
・ Application width: 240 mm
・ Liquid surface height: 193 mm (nozzle feeder coating liquid discharge port height)
・ Applicator roll diameter: Φ200mm
・ Coating speed: 150 m / min <Nozzle feeder conditions>
・ Nozzle feeder tilt angle θ: 35 degrees ・ Nozzle feeder slot gap G: 500 μm
・ Distance between nozzle feeder and applicator roll d: 150 μm
・ Nozzle feeder discharge liquid flow rate: 900 g / min (discharge width: 240 mm)

[Comparative Example 2]
In this comparative example, a coating apparatus for directly coating the coating liquid on the applicator roll 2 using the offset die 14 that does not use the liquid dam shown in FIG. 6 was used. Using this apparatus, coating was performed for 1 hour under the following conditions, and the presence or absence of coating defects (such as streaks or liquid breakage) was evaluated.
<Application conditions>
・ Coating liquid: Acrylic emulsion paste ・ Viscosity: 500 mPa · s (Shear rate: 3000 s ⁻¹ )
-Coating liquid adhesion amount on the web: 25 g / m ² (coating liquid layer thickness: 25 μm)
・ Application width: 240 mm
・ Applicator roll diameter: Φ200mm
<Offset die conditions>
・ Offset die inclination angle α: 15 degrees ・ Slot gap: 200 μm
Applicator roll to offset die gap K: 30 μm
・ Offset die liquid flow rate: 900 g / min (discharge width 240 mm)
Next, the results of Example 3 and Comparative Example 2 are shown in FIG. From this result, in Comparative Example 2, foreign matter was clogged at the tip of the offset die and coating streaks occurred, whereas in Example 3 of the present invention, a good coating liquid layer was formed without coating defects. .

[Example 4]
In this embodiment, the coating apparatus shown in FIGS. 1 to 3 is used, and coating is performed under the following conditions. did.
<Application conditions>
-Coating solution: PVA318 aqueous solution (Kuraray Co., Ltd.)
Viscosity: 500 mPa · s (B-type viscometer No. 2)
-Coating liquid adhesion amount on the web: 25 g / m ² (coating liquid layer thickness: 25 μm)
・ Application width: 240 mm
・ Applicator roll rotation speed: 125 m / min ・ Liquid surface height: 193 mm (nozzle feeder coating liquid discharge port height)
・ Applicator roll diameter: Φ200mm
・ Coating speed: 150 m / min <Nozzle feeder conditions>
・ Nozzle feeder inclination angle θ: 35 degrees ・ Nozzle feeder slot gap G: 500 μm
・ Distance between nozzle feeder and applicator roll d: 150 μm
Next, the results of Example 4 are shown in FIG. From this result, it is clear that occurrence of liquid breakage is suppressed by setting the nozzle feeder discharge liquid flow rate equal to or greater than the web application amount.

[Example 5]
In this example, using the coating apparatus shown in FIGS. 1 to 3, coating was performed under the following conditions, the nozzle feeder inclination angle was changed, and the presence or absence of liquid breakage of the coating liquid layer 101 formed on the peripheral surface of the applicator roll 2 was evaluated. .
<Application conditions>
-Coating solution: PVA318 aqueous solution (Kuraray Co., Ltd.)
Viscosity: 500 mPa · s (B-type viscometer No. 2)
-Coating liquid adhesion amount on the web: 25 g / m ² (coating liquid layer thickness: 25 μm)
・ Application width: 240 mm
・ Applicator roll rotation speed: 125 m / min ・ Liquid surface height: 193 mm (nozzle feeder coating liquid discharge port height)
・ Applicator roll diameter: Φ200mm
・ Coating speed: 150 m / min <Nozzle feeder conditions>
・ Nozzle feeder discharge liquid flow rate: 900 g / min (discharge width: 240 mm)
・ Nozzle feeder slot gap G: 500 μm
・ Distance between nozzle feeder and applicator roll d: 150 μm
Next, the result of Example 5 is shown in FIG. From this result, it is clear that the nozzle feeder inclination angle θ is appropriately 30 to 40 degrees when the diameter of the applicator roll is 200 mm and the liquid surface height is 193 mm.

[Example 6]
In the present embodiment, the coating apparatus shown in FIGS. 1 to 3 is used, coating is performed under the following conditions, the distance d between the nozzle feeder and the applicator roll is changed, and the coating liquid layer 101 formed on the peripheral surface of the applicator roll 2 is broken. The presence or absence of was evaluated.
<Application conditions>
-Coating solution: PVA318 aqueous solution (Kuraray Co., Ltd.)
Viscosity: 500 mPa · s (B-type viscometer No. 2 rotor)
-Coating liquid adhesion amount on the web: 25 g / m ² (coating liquid layer thickness: 25 μm)
・ Application width: 240 mm
・ Applicator roll rotation speed: 125 m / min ・ Liquid surface height: 193 mm (nozzle feeder coating liquid discharge port height)
・ Applicator roll diameter: Φ200mm
・ Coating speed: 150 m / min <Nozzle feeder conditions>
・ Nozzle feeder discharge liquid flow rate: 900 g / min (discharge width: 240 mm)
・ Nozzle feeder slot gap G: 500 μm
Nozzle feeder inclination angle θ: 35 degrees Next, the results of Example 6 are shown in FIG. From this result, when the distance d between the nozzle feeder and the applicator roll corresponds to 12 times (300 μm) the thickness of the coating liquid layer formed on the web, the occurrence of liquid breakage is not recognized, but 12 times It is found that the occurrence of liquid breakage is recognized when the distance d exceeds. Even though the distance d was 20 μm and 0.8 times the coating liquid layer thickness on the web, no liquid breakage was observed, but foreign matter was clogged at the tip of the lip of the nozzle feeder. In some cases, coating defects similar to those in Example 2 were observed.

[Example 7]
In this embodiment, using the coating apparatus shown in FIGS. 1 to 3, coating is performed under the following conditions, the liquid surface height in the liquid dam is changed, and the liquid of the coating liquid layer 101 formed on the peripheral surface of the applicator roll 2 is removed. The presence or absence was evaluated.
<Application conditions>
-Coating solution: PVA318 aqueous solution (Kuraray Co., Ltd.)
Viscosity: 500 mPa · s (B-type viscometer No. 2 rotor)
-Coating liquid adhesion amount on the web: 25 g / m ² (coating liquid layer thickness: 25 μm)
・ Application width: 240 mm
・ Applicator roll rotation speed: 125 m / min ・ Applicator roll diameter: Φ200 mm
・ Coating speed: 150 m / min <Nozzle feeder conditions>
・ Nozzle feeder discharge liquid flow rate: 900 g / min (discharge width: 240 mm)
・ Nozzle feeder slot gap G: 500 μm
・ Nozzle feeder inclination angle θ: 35 degrees ・ Distance between nozzle feeder and applicator roll d: 150 μm
Next, the result of Example 7 is shown in FIG. From this result, when the liquid level in the liquid dam is 10 mm higher than the height of the coating liquid discharge port of the nozzle feeder, the coating liquid discharge port of the nozzle feeder is soaked in the liquid dam and the coating liquid is discharged with the discharge coating liquid. If the vortex is generated in the liquid and the occurrence of liquid breakage is observed, and the liquid level in the liquid dam is 10 mm lower than the height of the coating liquid discharge port of the nozzle feeder, the coating liquid discharge port is above the coating liquid level. It is clear that the coating liquid supply start part of the applicator roller and the coating liquid surface in the liquid dam are separated from each other, air entrainment occurs, and liquid breakage occurs. On the other hand, if the liquid level in the liquid dam is set to be within +5 mm to −5 mm with respect to the height of the coating liquid discharge port of the nozzle feeder, air entrainment is suppressed and occurrence of liquid breakage is suppressed. It is clear that

[Example 8]
In this example, using the coating apparatus shown in FIGS. 1 to 3, when the coating liquid outflow prevention plate 13 is not used and the material of the coating liquid outflow prevention plate 13 is changed, the applicator roll is rotated for 1 hour under the following conditions: The state of liquid leakage of the coating liquid from the contact surface (see FIG. 3) between the nozzle feeder 6 and the coating liquid outflow prevention plate 13 and the contact surface (see FIG. 3) between the nozzle feeder 6 and the side deckle 5b was evaluated. .
<Application conditions>
-Coating solution: PVA318 aqueous solution (Kuraray Co., Ltd.)
Viscosity: 500 mPa · s (B-type viscometer No. 2 rotor)
-Coating liquid adhesion amount on the web: 25 g / m ² (coating liquid layer thickness: 25 μm)
・ Application width: 240 mm
・ Applicator roll rotation speed: 150 m / min ・ Applicator roll diameter: Φ200 mm
・ Liquid surface height: 193 mm (nozzle feeder coating liquid discharge port height)
<Nozzle feeder conditions>
・ Nozzle feeder discharge liquid flow rate: 900 g / min (discharge width: 240 mm)
・ Nozzle feeder slot gap G: 500 μm
・ Nozzle feeder inclination angle θ: 35 degrees ・ Distance between nozzle feeder and applicator roll d: 150 μm
Next, the result of Example 7 is shown in FIG. From this result, when the coating liquid outflow prevention plate is not used, the coating liquid leaks out from the contact surface between the nozzle feeder and the side deckle and stains the surroundings, while soft PTFE (polytetrafluoroethylene) is used. ) Or a rubber coating for preventing the coating liquid from flowing out, even if the nozzle feeder is moved back and forth, the contact surface between the nozzle feeder and the coating liquid outflow preventing plate is elastically adhered. It is clear that no leakage of the coating solution from this contact surface is observed.

It is sectional drawing which shows schematic structure of the coating device which concerns on one Embodiment by this invention. It is a side view of the coating device shown in FIG. It is a side view explaining the movement of the nozzle feeder of the coating device shown in FIG. It is a table | surface figure which shows the evaluation result which concerns on Example 1 by this invention. It is a table | surface figure which shows the evaluation result which concerns on Example 2 by this invention. It is sectional drawing which shows schematic structure of the coating device used by the comparative example 2. FIG. It is a table | surface figure which shows the evaluation result which concerns on Example 3 and Comparative Example 2 by this invention. It is a table | surface figure which shows the evaluation result which concerns on Example 4 by this invention. It is a table | surface figure which shows the evaluation result which concerns on Example 5 by this invention. It is a table | surface figure which shows the evaluation result which concerns on Example 6 by this invention. It is a table | surface figure which shows the evaluation result which concerns on Example 7 by this invention. It is a table | surface figure which shows the evaluation result which concerns on Example 8 by this invention. It is sectional drawing which shows schematic structure of the conventional coating device. It is sectional drawing for demonstrating the air entrainment phenomenon of the conventional coating device. It is sectional drawing which shows schematic structure of the other conventional coating device.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Metering roll, 2 ... Applicator roll, 2a ... Circumferential surface, 2b ... Center axis, 2c ... Coating liquid supply start part, 3 ... Backup roll, 4 ... Web, 5 ... Liquid dam, 5b ... Side deckle, 6 ... Nozzle feeder, 6a ... Lip part, 6b ... Coating liquid discharge port, 7 ... Manifold, 8 ... Slot, 10 ... Coating liquid, 10a ... Coating liquid surface, 13 ... Coating liquid outflow prevention plate, 101, 102 ... Coating liquid Layer, d: interval between nozzle feeder and applicator roll, θ: nozzle feeder tilt angle, H: coating liquid layer thickness, G: nozzle feeder slot gap

Claims (13)

The coating liquid is supplied from a liquid dam that stores the coating liquid through a gap between a rotating metering roll and an applicator roll that rotates in the direction opposite to the rotation direction of the metering roll, and the coating liquid has a predetermined thickness on the surface of the applicator roll. Forming a layer and rolling the coating liquid layer onto the web on a backup roll that rotates in the direction opposite to the rotation direction of the applicator roll while being pressed against the applicator roll through the web, and coating the coating liquid on the web In the coating method to
In the liquid dam, a nozzle feeder for supplying the application liquid to the applicator roll is provided, and the application liquid is supplied from the application liquid discharge port of the nozzle feeder to the supply start part of the applicator roll, and the peripheral surface of the applicator roll A coating method comprising forming a coating liquid layer having a predetermined thickness on the substrate. The coating method according to claim 1,
A coating method, wherein a coating speed for coating a coating liquid on the web is 100 m / min or more. The coating method according to claim 1 or 2,
The nozzle feeder discharges the coating liquid from the coating liquid discharge port toward the supply start portion of the peripheral surface of the applicator roll toward the central axis of the applicator roll. The coating method according to any one of claims 1 to 3,
The coating liquid discharge port of the nozzle feeder is separated within a range of 1 to 12 times the thickness of the coating liquid layer for applying the coating liquid to the web from the supply start part of the applicator roll, and the coating liquid discharge port is A coating method comprising discharging a coating liquid to a supply start portion of an applicator roll. The coating method according to any one of claims 1 to 4,
A coating method, wherein the coating liquid is discharged from a coating liquid discharge port of the nozzle feeder while applying a liquid pressure to a supply start portion of the applicator roll. The coating method according to any one of claims 1 to 5,
The coating liquid discharged from the coating liquid discharge port of the nozzle feeder to the applicator roll is set to be equal to or larger than the coating amount for applying the coating liquid to the web, and the coating liquid is discharged from the coating liquid discharge port. Application method. The coating method according to any one of claims 1 to 6,
A coating method comprising adjusting a liquid surface height in the liquid dam so as to be the same height as a coating liquid discharge port of the nozzle feeder. A liquid dam for storing the coating liquid, a rotating applicator roll to which the coating liquid is supplied from the liquid dam, and rotating in the reverse direction to the rotation direction of the applicator roll, and supplying the coating liquid from the gap with the applicator roll. A metering roll for forming a coating liquid layer having a predetermined thickness on the surface of the applicator roll, and the application liquid on the web by rotating in the reverse direction to the rotation direction of the applicator roll while being pressed against the applicator roll via the web. In a coating apparatus that coats a web with a coating liquid that includes a backup roll for transferring the layer,
A coating apparatus comprising: a nozzle feeder having a coating liquid discharge port that discharges a coating liquid to a coating liquid supply start portion of the applicator roll in the liquid dam. The coating apparatus according to claim 8, wherein
The coating liquid discharge port of the nozzle feeder is disposed toward the central axis of the applicator roll, and the coating liquid is discharged from the coating liquid discharge port toward the central axis of the applicator roll. apparatus. The coating apparatus according to claim 8 or 9,
An applicator characterized in that a variable means for changing a distance between the applicator roll and a coating liquid discharge port of the nozzle feeder in a range of 0 to 1 mm is provided in the nozzle feeder. The coating apparatus according to any one of claims 8 to 10,
It has the coating liquid discharge port set to the range of 1 to 2 times the coating amount which apply | coats the said coating liquid to the said web from the coating liquid discharge port of the said nozzle feeder. A characteristic coating apparatus. The coating apparatus according to any one of claims 8 to 11,
A coating apparatus comprising liquid level height adjusting means so that a liquid level in the liquid dam is equal to a height of a coating liquid discharge port of the nozzle feeder. The coating apparatus according to any one of claims 8 to 12,
The nozzle feeder is mounted on a side deck that prevents the coating liquid in the liquid dam from flowing out in the axial direction of the applicator roll, and the coating liquid outflow prevention plate is disposed between the side deck and the nozzle feeder. A coating apparatus characterized by comprising:

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