JP4681772B2 - Coating equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a coating apparatus for applying a coating liquid to a long web.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, there is a so-called liquid dam type coating apparatus as one of coating apparatuses for coating a coating liquid on a long web such as a film, fabric, or paper.
[0003]
In this liquid dam type coating apparatus, for example, a comma-type roll is disposed above a backup roll that conveys a web, and a liquid dam that stores a coating liquid is provided on the side of the backup roll.
[0004]
When the web is applied by this liquid dam type coating apparatus, the web is conveyed by the backup roll and passed through the liquid dam as described above. Then, the coating liquid is applied at the doctor edge portion of the comma type roll.
[0005]
[Problems to be solved by the invention]
In the liquid dam type coating apparatus as described above, when the web enters the liquid dam, air is simultaneously entrained, and when the coating liquid is applied to the surface of the web, the bubbles are mixed and bubbles are formed on the coated surface. And there is a problem that uneven coating occurs.
[0006]
In particular, in recent coating apparatuses, it is required to transport and apply a web at a high speed of 30 m / min or more, or to apply a high-viscosity coating liquid. However, the higher the coating speed and the higher the viscosity of the coating liquid, the more the web will bring air into the liquid dam, resulting in air bubbles and coating on the coating surface as described above. There is a problem that unevenness of work occurs more.
[0007]
Therefore, in view of the above problems, the present invention provides a liquid dam type coating apparatus in which bubbles and coating unevenness do not occur on the coated surface even when a high-speed coating or a high-viscosity coating liquid is applied. It is.
[0008]
[Means for Solving the Problems]
According to the first aspect of the present invention, there is provided a liquid dam in which a comma-type roll is disposed above a backup roll on which a long web travels, and the coating liquid is accumulated on the comma-type roll from the web travel side of the backup roll. In the coating apparatus provided, a gap for the web to enter is provided between the backup roll and the bottom surface of the liquid dam, and the axial direction of the backup roll is below the liquid dam and immediately before the gap. along the compartmented suction space provided with an external, the suction space is provided inside of the suction device for sucking the air body, the liquid the backup roll and the opposite shape of the opposing surface that is continuous from the bottom of the dam The coating apparatus is formed so as to become narrower as it approaches the gap .
[0009]
In the invention of claim 2, a doctor knife is disposed above the backup roll on which the long web travels, and a liquid dam is provided for storing the coating liquid from the web traveling side of the backup roll to the doctor knife. In the coating apparatus, a gap is provided between the backup roll and the bottom surface of the liquid dam to allow the web to enter, and is below the liquid dam and along the axial direction of the backup roll immediately before the gap. Te, the partitioned suction space provided with an external, a suction device for sucking the suction space inside the air body is provided, the shape of the liquid facing surface of the backup roll and opposed continuous from the bottom of the dam, the The coating apparatus is characterized by being formed so as to become narrower as it approaches the gap .
[0011]
A third aspect of the present invention is the coating apparatus according to the first or second aspect, wherein the suction space is narrowed toward the backup roll.
[0012]
A fourth aspect of the present invention is the coating apparatus according to the first or second aspect, wherein the facing surface is an inclined surface.
[0013]
A fifth aspect of the present invention is the coating apparatus according to the first or second aspect, wherein the facing surface is formed by a multi-step inclined surface.
[0014]
A sixth aspect of the present invention is the coating apparatus according to the first or second aspect, wherein the facing surface is an arc surface.
[0015]
In the coating apparatus according to claims 1 and 2, the web passes through the suction space immediately before entering the liquid dam by the backup roll. Since the gas is sucked by the suction means in this suction space, the air on the surface of the web is also sucked at the same time, so that the air is not entrained with the web inside the liquid dam.
[0016]
Further, since the facing surface becomes narrower as it approaches the gap, the labyrinth effect increases the pressure of the coating liquid in the gap portion, and more reliably prevents air from being caught together with the web.
[0017]
In the coating apparatus according to the third aspect , since the suction space becomes narrower as it approaches the backup roll, it is possible to prevent the web from being sucked together with the suction when the suction means sucks the gas.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
(First embodiment)
Hereinafter, a liquid dam type coating apparatus 10 according to a first embodiment of the present invention will be described with reference to FIGS. 1 and 2.
[0019]
(1) Configuration of Coating Device 10 FIG. 1 is an overall view of a liquid dam type coating device 10.
[0020]
As described above, the coating apparatus 10 is a liquid dam system, and a comma-type roll 14 is disposed above a backup roll 12 that conveys a long web W such as a film, fabric, or paper. Further, a liquid dam 16 for storing a high-viscosity coating liquid is formed from the web roll side of the backup roll 12 to the comma-type roll 14.
[0021]
The backup roll 12 rotates with the conveyance speed V of the web W. This conveyance speed V is a high-speed conveyance of 30 to 40 m / min.
[0022]
In the comma-type roll 14, a doctor edge 18 for coating the coating liquid at an axially symmetric position on the surface of the roll protrudes along the axial direction, and the shape of the longitudinal section is formed in a substantially comma shape.
[0023]
The liquid dam 16 has a back plate 20 and a bottom plate 22 extending from the lower end of the back plate 20 in the direction of the backup roll 12. A pair of side plates (not shown) is provided on both sides of the back plate 20.
[0024]
A liquid dam 16 that is a space for storing the coating liquid is formed by the back plate 20, the bottom plate 22, both side plates (not shown), the backup roll 12, and the comma roll 14.
[0025]
A suction space 24 for sucking air is formed below the bottom plate 22 of the liquid dam 16 along the axial direction of the backup roll 12.
[0026]
Next, the liquid dam 16 and the suction space 24 will be described in detail with reference to FIG.
[0027]
A gap 26 for passing through the web W is provided between the bottom plate 22 of the liquid dam 16 and the backup roll 12. The dimension A of the gap 26 is 0.1 mm to 2 mm while the web W is passing.
[0028]
A labyrinth member 28 is provided above the bottom plate 22. An upper surface 30 of the labyrinth member 28 is parallel to the bottom plate 22, and an opposing surface 32 is provided continuously from the upper surface 30. The facing surface 32 faces the backup roll 12, is formed by the first inclined surface 34 and the second inclined surface 36, and the distance between the facing surface 32 and the backup roll 12 becomes closer to the gap 26. Is formed to be narrow. And angle (theta) where the 1st inclined surface 34 and the 2nd inclined surface 36 cross is formed in less than 180 degrees.
[0029]
In the present specification, the bottom surface and the bottom plate of the liquid dam 16 are separately used, and the bottom surface of the liquid dam 16 is a surface formed by the top surface 30 of the labyrinth member 28, and the bottom plate of the liquid dam 16 is , Means the bottom plate 22, that is, the member name.
[0030]
The suction space 24 provided below the bottom plate 22 of the liquid dam 16 is provided along the axial direction of the backup roll 12, and has a substantially triangular longitudinal section as shown in FIG. The distance B in contact with the web W is about 10 mm. A suction port 38 is provided in a portion facing the surface in contact with the web W. The suction port 38 is provided with a suction pump 40 and has a structure for sucking air inside the suction space 24.
[0031]
Further, the suction port 38 is provided at one place in the substantially central portion of the backup roll 12 in the axial direction.
[0032]
(2) Operating state of coating apparatus The operating state of the coating apparatus 10 having the above-described configuration will be described.
[0033]
When the web W is conveyed by the backup roll 12, the web W first enters the suction space 24. At this time, in the suction space 24, the air attached to the surface of the web W is sucked from the suction port 38 by the suction pump 40 and is separated from the surface of the web W. In this case, since the shape of the longitudinal section of the suction space 24 becomes narrower as it approaches the backup roll 12 (distance B is about 10 mm), the portion where the web W is sucked is short, and the web W is the surface of the backup roll 12. It is not sucked away from the direction of the suction port 38.
[0034]
Subsequently, the web W enters the liquid dam 16 through the gap 26. Then, the coating liquid adheres to the surface of the web W. In this case, since the facing surface 32 of the labyrinth member 28 is formed narrower as it approaches the gap 26, the pressure of the coating liquid increases as it approaches the gap 26, thereby more reliably preventing air entering from the suction space 24. be able to. That is, the inclination of the first inclined surface 34 and the second inclined surface 36 of the facing surface 32 of the labyrinth member 28 generates a so-called labyrinth effect.
[0035]
When the coating liquid adheres at the liquid dam 16 and reaches the position of the doctor edge 18 of the comma roll 14, the coating liquid is applied to the surface of the web W by the pressure of the doctor edge 18.
[0036]
In this case, air can be prevented from entering the liquid dam 16 by suction and the labyrinth effect by the suction space 24, so that bubbles and coating unevenness do not occur on the coated surface of the surface of the web W. Therefore, as a suitable use example of the coating apparatus 10 of a present Example, it is the case where it coats at high speed (30 m / min or more), and the case where a highly viscous coating liquid is coated.
[0037]
(Second embodiment)
The coating apparatus 10 of the 2nd Example of this invention is demonstrated based on FIG.
[0038]
In the liquid dam type coating apparatus 10 of the first embodiment, the comma type roll 14 is used, but in this embodiment, a doctor knife 40 is provided above the backup roll 12 instead of the comma type roll 14. is there. Other structures are the same as those of the coating apparatus 10 of the first embodiment.
[0039]
Even in the coating apparatus 10 of the present embodiment, when a coating surface is formed on the web W by the doctor knife 40, bubbles and coating unevenness do not occur.
[0040]
(Modification 1)
In each of the embodiments described above, the facing surface 32 of the labyrinth member 28 has a shape in which the first inclined surface 34 and the second inclined surface 36 are continuous, but instead of this, a combination of further multi-step inclined surfaces. Alternatively, it may be a simple inclined surface. Moreover, you may form by a circular arc surface.
[0041]
(Modification 2)
In each of the above-described embodiments, the suction port 38 is provided at one location in the substantially central portion of the backup roll 12 in the axial direction.
[0042]
For example, the suction port 38 may be provided at three locations near the central portion and both side portions of the backup roll 12 in the axial direction.
[0043]
In addition, the suction port 38 may be provided at one location in the substantially central portion of the backup roll 12 in the axial direction, and a guide plate for uniformly sucking suction may be provided inside the suction space 24.
[0044]
【The invention's effect】
As described above, in the coating apparatus of the present invention, when a coating surface is formed on the surface of the web by a comma roll or a doctor knife, there is no occurrence of air bubbles or coating unevenness, and coating is performed with a target coating thickness. The working fluid can be applied.
[Brief description of the drawings]
FIG. 1 is an explanatory view of a coating apparatus showing a first embodiment of the present invention.
FIG. 2 is an enlarged longitudinal sectional view of a main part of the liquid dam and the suction space.
FIG. 3 is an explanatory diagram of a coating apparatus according to a second embodiment.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Coating apparatus 12 Backup roll 14 Comma-type roll 16 Liquid dam 24 Suction space 26 Gap 28 Labyrinth member 32 Opposite surface

Claims (6)

In the coating apparatus provided with a liquid dam for storing the coating liquid over the comma-type roll from the side on which the web in the backup roll travels by arranging a comma-type roll above the backup roll on which the long web runs.
Provide a gap for the web to enter between the backup roll and the bottom of the liquid dam,
A lower side of the liquid dam, along the axial direction of the backup roll immediately before the gap, the partitioned suction space provided with an external, a suction device provided to suck the suction space inside the air body,
The coating apparatus , wherein the shape of the facing surface facing the backup roll continuous from the bottom surface of the liquid dam is formed so as to become narrower as it approaches the gap . In the coating apparatus provided with a liquid dam for storing a coating liquid over the doctor knife from the side on which the web in the backup roll travels by arranging a doctor knife above the backup roll on which the long web travels,
Provide a gap for the web to enter between the backup roll and the bottom of the liquid dam,
A lower side of the liquid dam, along the axial direction of the backup roll immediately before the gap, the partitioned suction space provided with an external, a suction device provided to suck the suction space inside the air body,
The coating apparatus , wherein the shape of the facing surface facing the backup roll continuous from the bottom surface of the liquid dam is formed so as to become narrower as it approaches the gap . The suction space is coating apparatus according to claim 1 or 2, characterized in that narrower the closer to the backup roll. Wherein the facing surface, the coating apparatus of claim 1, wherein a formed by the inclined surface. Wherein the facing surface, the coating apparatus of claim 1, wherein a formed by the inclined surface of the multi-stage. Wherein the facing surface, the coating apparatus of claim 1, wherein a formed by an arc surface.

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