JPH0515828A - Pressurization type curtain coating device - Google Patents

Abstract

PURPOSE:To obtain the excellent pressurization type curtain coating device which forms a uniform curtain film and does not generate unequal coating and traces of foam by disposing defoaming nets extending to the entire width in the outlet within a curtain supplying header and providing an outlet port for air venting in the upper part thereof. CONSTITUTION:The defoaming nets 6, 7 extending to the entire width in the front part of the free falling curtain film are disposed and the outlet port 5 for air venting is provided in the upper part of the curtain supplying header. The mesh of the defoaming net 6 of the first stage is set in a 40 to 100 mesh range to break down large foam and to remove the foreign matter remaining in a coating material. The mesh of the defoaming net 7 of the second stage is set in a 150 to 200 mesh range to extremely uniformize the free falling curtain film. Thus, the coating liquid supplied from a coating material inflow port 4 is formed as the curtain film 2 by the free falling from the curtain supply header 3 and is applied on a continuously traveling web 8. The high-quality coated sheet which is free from the unequal coating and the traces of the foam is stably obtd.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pressure type curtain coating apparatus, and more particularly to removing bubbles existing in a coating liquid in a curtain supply header.

[0002]

2. Description of the Related Art Conventionally, a so-called curtain coating method for coating a web continuously running under a curtain of various coating liquids involves applying a pressure higher than atmospheric pressure to a coating liquid with a pressure dam. There are two main methods: a pressure-type curtain coating method that coats the web that is running continuously, and a dam-type curtain coating method that coats the coating liquid that has flowed down the inclined plate due to overflow from the dam onto the web. There is.

The pressure type curtain coating system has a problem of bubbles in the coating liquid. Since the coating liquid is mainly constituted by mixing solid such as pigment powder and liquid such as adhesive, many bubbles are generated in the preparation process. Further, since the coating liquid is pumped and circulated in the pipe, bubbles are generated also at this time.

These bubbles, when locally concentrated on a portion of the free-falling curtain film in the curtain supply header,
It creates a bubble-like streak and disturbs the curtain film. The uniformity of the curtain film is the most important point of coating by the curtain coating device, and bubbles in the coating liquid disturb the curtain film and cause uneven coating, which is a serious problem. Further, if the coating liquid containing many bubbles is applied as it is, there is a problem of bubbles traces in which the effects of bubbles appear on the application surface.

[0005]

SUMMARY OF THE INVENTION The present invention eliminates air bubbles in a coating liquid in a curtain supply header, forms a uniform curtain film, and obtains an excellent coating surface without uneven coating or bubbles. Provided is a pressure type curtain coating device which can be manufactured.

[0006]

SUMMARY OF THE INVENTION The present invention is characterized in that a defoaming net is provided in the curtain supply header over the entire width of the outlet, and an outlet for bleeding air is provided above the curtain supply header. It is a pressure type curtain coating device.

[0007]

The pressure type curtain coating apparatus of the present invention will be described in more detail with reference to the drawings. 1 (1) is a general outline of the pressure type curtain coating apparatus, in which the coating liquid supplied from the paint inlet (4) is formed on the free fall curtain film (2) by the curtain supply header (3), It is applied to the continuously running web (8).

In the present invention, the defoaming nets (6) and (7) are arranged in the front part of the outlet of the free-falling curtain film in the curtain supply header, and the air outlet is provided on the upper part of the curtain supply header for removing air. (5) is provided.

The mesh of the defoaming net is preferably 40 to 200 mesh. 40 mesh opening is 0.4
Air bubbles having a size of 8 mm and exceeding this size are destroyed by the pressure of the feed fluid of the paint. Further, in the case of 200 mesh, it becomes 0.076 mm similarly, and finer bubbles are destroyed.
Bubbles that do not pass through the net are taken out from the air outlet.

If the mesh of the defoaming net exceeds 40 mesh and is coarse, the problem will not be solved because curtains will be formed with many small bubbles. On the other hand, if a net finer than 200 mesh is used, it is not suitable for use because clogging easily occurs due to minute foreign matters in the coating liquid.

In the present invention, the defoaming nets may be arranged in multiple stages to further improve the effect and achieve more stable coating. In this case, the upper mesh of the defoaming nets arranged in multiple stages has a coarser mesh.

Further, the most preferable effect can be obtained by setting the mesh of the first-stage defoaming net in the range of 40 to 100 mesh and the mesh of the second-stage defoaming net in the range of 150 to 200 mesh.

The mesh of the first-stage defoaming net is 40 to 1
If it is used in the range of 00 mesh, it destroys large air bubbles and at the same time removes foreign substances such as dust remaining in the paint, which helps the effect of the finer mesh in the second stage. 40
If it is coarser than the mesh, it is less effective in removing foreign matter such as dust. If it is finer than 100 mesh, clogging may occur and it may become unstable.

The second-stage defoaming net mesh is 150-
When used in the range of 200 mesh, the free-fall curtain film becomes extremely uniform and a sufficient effect can be obtained. 150
If the mesh is coarser than the mesh, the bubbles that have passed through leave a bad influence, while as described above, when a net finer than 200 mesh is used, it is easy to cause clogging due to minute foreign matters in the coating liquid.

As the defoaming net member of the present invention, a non-rust material such as a plastic material or stainless steel is desirable.

[0016]

EFFECTS OF THE INVENTION According to the pressure type curtain coating apparatus of the present invention, the problem caused by bubbles in the coating liquid can be solved and a high-quality coating sheet free from uneven coating and bubble traces can be stably obtained.

[Brief description of drawings]

FIG. 1 shows a pressure type curtain coating apparatus of the present invention.

[Explanation of symbols]

1 ... Pressure type curtain coating device 2. Free fall curtain film 3. Curtain supply header 4 ... Paint inlet 5: Air vent outlet 6 ... First-stage defoaming net 7 ... second-stage defoaming net 8 ... Web

Claims (4)

[Claims] 1. A pressure type curtain coating apparatus, wherein a defoaming net is arranged in the curtain supply header over the entire width of the outlet, and an air outlet for bleeding air is provided above the curtain supply header. 2. The pressure type curtain coating apparatus according to claim 1, wherein the mesh of the defoaming net is in the range of 40 to 200 mesh. 3. The pressure type curtain coating apparatus according to claim 1, wherein the defoaming nets are arranged in multiple stages to form a coarser mesh in the upper stage. 4. The first-stage defoaming net mesh is 40 to 1
The pressure-type curtain coating device according to claim 3, wherein the mesh of the second-stage defoaming net is in the range of 150 to 200 mesh in the range of 00 mesh.