JP2006314892A - Apparatus and method for applying coating liquid - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an apparatus for applying a coating liquid, in which such a trouble can be prevented that the thickness of the coating liquid becomes uneven owing to a sag of a web. <P>SOLUTION: The apparatus for applying the coating liquid is constituted so that the web 3 traveling continuously is supported by two rolls arranged orthogonally to the traveling direction of the web and the coating liquid is applied to the web between two rolls. The circumferential speed of the upstream-side roll 1 arranged on the upstream side of the traveling direction of the web is made lower than the traveling speed of the web 3 and that of the downstream-side roll 2 arranged on the downstream side of the traveling direction of the web is made higher than the traveling speed of the web 3. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a coating apparatus and a coating method for supporting a continuously traveling web with two rolls arranged in a direction orthogonal to the traveling direction, and applying a coating liquid to the web between the two rolls.

FIG. 7 shows a coating apparatus that supports a continuously traveling (conveyed) web with two rolls arranged in a direction orthogonal to the traveling direction, and applies a coating liquid to the web between the two rolls. There is a metering bar coating device shown, and a die coating device shown in FIG.
In FIG. 7, the web 3 continuously conveyed is supported by two rolls (an upstream roll 1 on the upstream side in the running direction and a downstream roll 2 on the downstream side) arranged at right angles to the running direction. The coating liquid 4 is applied to one side of the web 3 between the rolls 1 and 2 using the metering bar coating unit 5.
In FIG. 8, the web 3 that is continuously conveyed is supported by two rolls (an upstream roll 1 on the upstream side in the running direction and a downstream roll 2 on the downstream side) arranged at right angles to the running direction. The coating liquid 4 is applied to one side of the web 3 between the rolls 1 and 2 using the die coating unit 6.
In any of these coating devices, if there is a partial slack in the web, there is a coating uniformity trouble that the coating amount of the coating solution partially decreases or conversely the coating amount partially increases. generate.
In order to solve this problem, measures are generally taken to increase the tension of the web and elastically deform the web to obtain the flatness of the web between the two rolls. There is a limit to the tension that can be set because it involves problems such as wrinkling in web conveyance, and it has not been a technique that can cope with various slacks.
In addition, as in the technique disclosed in Patent Document 1, for example, at least one of the two rolls is used as a roll (expanding roll) capable of applying tension in the width direction to the web. And a technique for dealing with slackness by displacing at least one end of one of the two rolls in the thickness direction of the web, such as a technique for correcting the slack, and a technique disclosed in Patent Document 2. .
Japanese Patent No. 3291822 Japanese Patent Publication No. 06-9670

However, any of the above prior arts has limitations on the degree of correction of slack that can be effective and the correspondence of the slack generation position in the web width direction, etc., and cannot be widely used in various slack situations.
An object of the present invention is to provide a coating apparatus and a coating method capable of preventing a coating uniformity trouble due to web slack.

In order to achieve the above-mentioned object, the invention according to claim 1 supports a continuously running web with two rolls arranged perpendicular to the running direction, and the coating liquid is applied to the web between the two rolls. In the coating device to be coated, the coating device in which the upstream roll circumferential speed on the upstream side in the web running direction is slower than the web running speed and the downstream roll circumferential speed on the downstream side in the web running direction is faster than the web running speed is the most. Main features.
The invention according to claim 2 is mainly characterized in that the coating apparatus according to claim 1 is made of a material having a large friction coefficient on the surface of the two rolls.
The invention according to claim 3 is characterized in that the coating apparatus according to claim 1 is characterized in that pores are provided on the surface of two rolls and the inside of the hollow roll is made negative pressure so that the web can be sucked. .
The invention according to claim 4 is characterized in that the coating apparatus according to claim 1 uses, as at least one of the upstream roll and the downstream roll, an expand roll having a function capable of applying a tension in the width direction to the web. To do.
The invention according to claim 5 is a coating method in which a continuously running web is supported by two rolls arranged at right angles to the running direction, and a coating solution is applied to the web between the two rolls. The most important feature is an application method in which the upstream roll peripheral speed on the upstream side in the direction is made slower than the traveling speed of the web, and the downstream roll peripheral speed on the downstream side in the web traveling direction is made faster than the traveling speed of the web.

  According to the present invention, in a coating apparatus that supports a continuously traveling web with two rolls arranged at right angles to the traveling direction and applies a coating liquid to the web between the two rolls, the web traveling direction upstream The web side upstream roll peripheral speed is slower than the web travel speed, and the downstream roll peripheral speed downstream in the web travel direction is made faster than the web travel speed, preventing coating uniformity problems due to web slack. it can.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a conceptual diagram of a coating apparatus (metering bar coating method) according to an embodiment of the present invention. The coating apparatus according to the embodiment of the present invention has the same configuration as that in FIG. 7 and the peripheral speed of the rollers is different. The same description as in the conventional example shown in FIGS. In this embodiment, each of the two rolls (upstream roll 1 and downstream roll 2) has a mechanism (not shown) that can arbitrarily adjust the circumferential speed. circumferential speed of ₁ and the downstream roller 2: V ₂ is the traveling speed of the web 3: is set to keep the V ₁ relative to V ₀ <V ₀ <V ₂ conditions.
FIG. 2 is a sectional view of a first example of a roll in the coating apparatus shown in FIG. In the roll 1 or 2, the surface of the roll base material 7 is covered with a material 8 having a large friction coefficient. Here, the material 8 having a large friction coefficient means a material having a friction coefficient larger than that of the surface of the roll base material, for example, a rubber material or a cork material.
FIG. 3 is a cross-sectional view of a second example of a roll in the coating apparatus shown in FIG. The roll 1 or 2 has a hollow structure and is provided with pores 9 (passing through the thickness of the base material 7) on the surface of the roll base material 7. Further, although not shown, the air inside the roll is axially directed. It has a mechanism to exhaust. As a result, the web 3 in contact with the rolls 1 and 2 is sucked by exhausting the air inside the roll (negative pressure), and the web is sucked to the roll surface through the pores 9, whereby the roll and web It is possible to increase the contact pressure.
FIG. 4 is a view showing an example in which the roll of the third example is used as the upstream roll in the coating apparatus shown in FIG. As the upstream roll 1, an expanding roll 10 having a function capable of applying a tension in the width direction to the web is used.

FIG. 5 is a view showing an example in which the rolls shown in the third example are used as the upstream roll 1 and the downstream roll 2 in the coating apparatus shown in FIG. That is, the expanding roll 10 is used as the upstream roll 1 and the downstream roll 2.
The expand roll 10 is a roll that is generally used for the purpose of preventing wrinkling of the web 3, and has a mechanism in which a portion that extends in the axial direction and a portion that contracts in the axial direction are generated on the surface of the roll. By causing the web to contact the place where the surface of the roll extends in the axial direction, the web 3 is tensioned in the width direction to prevent wrinkling of the web 3. The usage in the present invention is the same, and the web 3 is set so that tension in the width direction is generated.
FIG. 6 is an explanatory view for explaining the operation of the coating apparatus shown in FIGS.
As described with reference to FIG. 1, the peripheral speed of the upstream roll 1: V ₁ and the peripheral speed of the downstream roll 2: V ₂ are V ₁ <V ₀ <V ₂ with respect to the travel speed of the web 3: V ₀ . By setting so as to maintain the conditions, the web tension between the rolls: T ₂ is set higher than those before and after the tension: T ₁ , T ₃ are maintained at a level that does not hinder the conveyance. be able to.
Thereby, since sufficient elastic deformation can be given to the web 3 between rolls, the slack of the web 3 is corrected and a flat web surface can be obtained. In the present invention, by adjusting V ₁ and V ₂ , the web tension between rolls: T ₂ can be set according to the slackness of the web 3, and the slack correction effect can be exhibited in various situations. it can.
With this action, for example, the metering bar coating method shown in FIGS. 1 and 7 can prevent the occurrence of excessive adhesion amount portions, and the die coating method shown in FIG. 8 can also prevent the occurrence of portions where no liquid is applied. become.

Next, as shown in FIG. 2, the surface of the roll 1 or 2 is made of the material 8 having a large friction coefficient, thereby reducing slippage between the roll surface (large friction coefficient material surface) and the web 3 and V ₁ <V _0. The effect of providing a speed difference of <V ₂ is easily exhibited. As a result, the web tension between rolls: T ₂ can be set in a wider range, so that various slack situations can be dealt with widely.
Next, as shown in FIG. 3, pores 9 are provided on the surface of the roll base material 7, and there is a mechanism for exhausting the air inside the roll in the axial direction. By sucking the web 3 with the rolls 1 and 2, The slippage between the roll surface and the web 3 is reduced, and the effect of providing a speed difference of V ₁ <V ₀ <V ₂ is easily exhibited. As a result, the web tension between the rolls: T ₂ can be set in a wider range, so that various slack situations can be dealt with widely.
Next, as shown in FIG. 4, the expanded roll 10 is used as the upstream roll 1, and as shown in FIG. 5, the expanded roll 10 is used as the upstream roll 1 and the downstream roll 2. In the web 3 between the rolls, the tension in the width direction can be further applied to the tension: T ₂ , so that the slack correction function is improved.

Next, examples will be described. The common conditions are as follows.
1) Coating base: PET base with a thickness of 25 μm and a width of 1000 mm. Base has slack due to elongation. 2) Base transport tension (T ₁ , T ₃ : 25 kgf / m to 30 kgf / m)
3) Coating solution: 10 wt% PVA aqueous solution 4) Coating speed: 50 m / min 5) Coating method: Metering bar coating (Example 1)
Continuous application under common conditions was performed using the roll shown in FIG.
Both rolls were covered with butyl rubber having a thickness of 5 mm.
Roll peripheral speed is web conveyance speed of 50 m / min: V ₁ = 47 m / min with respect to V ₀
V ₂ = 55 m / min
Set to.
Although the amount of liquid adhering near both ends of the web tended to increase relative to that at the center through continuous application of 10,000 m, the difference was within 6%.
(Example 2)
Continuous application under common conditions was performed using the roll shown in FIG.
Both rolls were made of sintered porous material, and the exhaust was taken so that the pressure difference between the inside and outside of the roll was 2000 mmAq.
Roll peripheral speed, web conveying speed of 50m / min: V with respect to V _{0 1} = 47m / min
V ₂ = 55 m / min
Set to.
Although the amount of liquid adhering near both ends of the web tended to increase relative to that at the center through continuous application of 10,000 m, the difference was within 6%.

(Example 3)
Continuous application under common conditions was performed using the rolls shown in FIGS.
Both rolls were expanded rolls, and the roll surface was set so that the axial elongation was 2.5 mm in total width.
Roll peripheral speed, web conveying speed of 50m / min: V with respect to V _{0 1} = 47m / min
V ₂ = 55 m / min
Set to.
Although there was a tendency that the amount of liquid adhering near both ends of the web through the continuous coating of 10,000 m tended to be larger than that at the center, the difference was within 5%.
(Comparative example)
The roll peripheral speed in the coating apparatus of the first embodiment, the web conveyance speed of 50 m / min: V relative to V _{0 1} = 50m / min
V ₂ = 50 m / min
Set to.
In the continuous coating of 10,000 m, the liquid adhesion amount in the vicinity of both ends of the web may increase by up to 30% with respect to that in the central portion, and satisfactory coating uniformity could not be obtained. In addition, there were frequent troubles with the guide roll due to insufficient drying during continuous application.

It is a conceptual diagram of the coating device (metering bar coating system) which concerns on embodiment of this invention. It is sectional drawing of the 1st example of the roll in the coating device shown in FIG. It is sectional drawing of the 2nd example of the roll in the coating device shown in FIG. It is a figure which shows the example which used the roll of the 3rd example as an upstream roll in the coating device shown in FIG. It is a figure which shows the example which used the roll of the 3rd example as an upstream roll and a downstream roll in the coating device shown in FIG. It is explanatory drawing explaining the effect | action of the coating device shown in FIG. 1 thru | or FIG. It is a block diagram of a metering bar coating device. It is a block diagram of a die coating device.

Explanation of symbols

1 upstream roll, 2 downstream roll, 3 web, 4 coating solution, 5 metering bar coating unit, 6 die coating unit, 7 roll base material, 8 large friction coefficient material, 9 pores, 10 expanding roll, V ₀ web conveyance speed, V ₁ upstream roll circumferential speed, V ₂ downstream roll circumferential speed, web tension between two rolls in T ₂ coating section, T ₁ , T ₃ web conveyance tension

Claims (5)

  In a coating apparatus that supports a continuously traveling web with two rolls arranged at right angles to the traveling direction and applies a coating solution to the web between the two rolls, the upstream roll circumference on the upstream side in the web traveling direction A coating apparatus characterized in that the speed is made slower than the running speed of the web, and the downstream roll peripheral speed on the downstream side in the web running direction is made faster than the running speed of the web.   The coating apparatus according to claim 1, wherein the two roll surfaces are made of a material having a large friction coefficient.   The two rolls are made hollow, and pores penetrating from the surface of each roll to the inside of the hollow are provided, and the web can be sucked to the roll surface through the pores when the inside of the hollow of each roll is made negative. The coating apparatus according to claim 1, wherein the coating apparatus is configured as described above.   2. The coating apparatus according to claim 1, wherein an expanding roll having a function capable of applying a tension in a width direction to the web is used for at least one of the upstream roll and the downstream roll.   In a coating method in which a continuously traveling web is supported by two rolls arranged at right angles to the traveling direction, and a coating liquid is applied between the two rolls, the upstream roll circumference on the upstream side in the web traveling direction A coating method characterized in that the speed is made slower than the running speed of the web, and the downstream roll peripheral speed on the downstream side in the web running direction is made faster than the running speed of the web.

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