JP2021112697A - Coating applicator - Google Patents

Abstract

To provide a coating applicator which can inhibit occurrence of coating stripes when applying a coating liquid to a web.SOLUTION: A coating applicator 1 includes: a bar 10 which applies a coating liquid L to a web W; and a bar holder 20 which includes a slit S for circulating the coating liquid L and is configured so that the coating liquid circulates a gap G formed between the bar and the bar holder from the lower side and overflows from the upper side.SELECTED DRAWING: Figure 1

Description

The present invention relates to a coating device.

Conventionally, a coating device for applying a coating liquid to an object to be coated such as a web has been known. The coating device is used, for example, to form a hard coat layer, an antireflection layer, an antifouling layer, a peeling layer, an ink receiving layer, an adhesive layer, a primer layer, and the like on an object to be coated.

In this regard, for example, in Patent Document 1 below, a coating liquid supply device for supplying and applying a coating liquid to the web and a coating amount adjusting device for adjusting the coating amount of the coating liquid applied to the web are provided. The coating apparatus to have is disclosed. In this coating device, a predetermined amount of coating liquid is applied to the web by applying the coating liquid stored in the liquid pan to the web with a pickup roll and removing the excess coating liquid applied to the web with a bar. ..

JP-A-2019-150777

However, in the above coating apparatus, air is entrained between the web and the pickup roll, and between the web and the bar, and the entrained air becomes minute bubbles and is mixed in the coating liquid. As a result, minute bubbles may stay in the vicinity of the rotating bar, and coating streaks may be generated on the web, resulting in poor coating.

The present invention has been invented to solve the above problems, and an object of the present invention is to provide a coating device capable of suppressing the occurrence of coating streaks when applying a coating liquid to a web.

The coating device of the present invention is provided with a bar for applying the coating liquid to the web and a slit through which the coating liquid flows, and the coating liquid flows from below and overflows from above in the gap between the bars. It has a bar holder configured in.

According to the coating apparatus according to the present invention, the coating liquid distributed from the bar holder is directly applied to the web by the bar without applying the coating liquid stored in the liquid pan to the web by the pickup roll. Therefore, it is possible to prevent the generation of coating streaks due to air bubbles generated between the web and the pickup roll. Further, since the coating liquid flows from below through the gap between the bar and the bar holder and the coating liquid overflows from above, air bubbles generated between the web and the bar can be suppressed. From the above, it is possible to provide a coating device capable of suppressing the occurrence of coating streaks when applying the coating liquid to the web.

It is the schematic which shows the coating apparatus which concerns on embodiment of this invention. It is a front view which shows a part of the coating apparatus which concerns on this embodiment. It is a side view which shows a part of the coating apparatus which concerns on this embodiment.

An embodiment of the present invention will be described with reference to FIGS. 1 to 3. In the description of the drawings, the same elements are designated by the same reference numerals, and duplicate description will be omitted. In addition, the dimensional ratios in the drawings are exaggerated for convenience of explanation and may differ from the actual ratios.

FIG. 1 is a schematic view showing a coating device 1 according to an embodiment of the present invention. FIG. 2 is a front view showing a part of the coating device 1 according to the present embodiment. FIG. 3 is a side view showing a part of the coating device 1 according to the present embodiment. In the following description, the direction in which the web W moves is the X direction (left direction in FIG. 1), the longitudinal direction in which the bar 10 and the bar holder 20 extend is the Y direction (right direction in FIG. 2), and the vertical direction is the Z direction. It is called.

The coating device 1 according to the present embodiment is a device for applying the coating liquid L to the web W. The coating device 1 is used, for example, to form a hard coat layer, an antireflection layer, an antifouling layer, a peeling layer, an ink receiving layer, an adhesive layer, a primer layer and the like on the surface of the web W. As shown in FIG. 1, the position of the web W is adjusted by the guide rolls R provided on the upstream side and the downstream side of the web W.

As shown in FIG. 1, the coating device 1 according to the present embodiment stores a bar 10 for applying the coating liquid L to the web W, a bar holder 20 having a slit S through which the coating liquid L flows, and the coating liquid L. 30, a liquid feeding pump 40 that sends the coating liquid L stored in the storage unit 30 toward the bar holder 20, a defoaming filter 50 that removes bubbles contained in the coating liquid L, and a feeding unit. It has a control unit (not shown) that controls the drive of the liquid pump 40.

The coating liquid L is not particularly limited, and is, for example, water or an organic solvent liquid of an organic compound, water of fine particles, an organic solvent dispersion liquid, or the like.

The web W includes paper, plastic film, laminated paper and the like. As the material of the plastic film, for example, polyolefins such as polyethylene and polypropylene, polyesters such as polyethylene terephthalate and polyethylene-2,6-naphthalate, cellulose acetates such as cellulose triacetate and cellulose diacetate, polyvinyl chloride and polyurethane are used. .. Further, as the resin used for the laminated paper, polyolefins such as polyethylene are typical, but the resin is not necessarily limited to this. The thickness of the web W is not particularly limited, but a web W having a thickness of about 0.01 mm to 1.0 mm is preferable from the viewpoint of versatility.

The bar 10 is rotatably attached around a shaft portion (not shown). The bar 10 is rotated by a drive unit (not shown) to apply the coating liquid L to the web W and weigh it. The rotation direction of the bar 10 is the same as the transport direction of the web W (counterclockwise in FIG. 1). The rotation direction of the bar 10 may be opposite to the transport direction of the web W (clockwise in FIG. 1).

The bar 10 extends along the Y direction. The bar 10 has a rod shape having an axial length equal to or greater than the length of the web W in the Y direction.

As shown in FIGS. 1 and 3, the bars 10 are arranged apart from the bar holder 20 so that a gap G is formed with respect to the bar holder 20 by a predetermined distance.

As the bar 10, a wire having a constant diameter is tightly wound around the surface of the mandrel, or a groove having a constant width and depth is provided on the surface of the mandrel at a constant pitch.

As shown in FIG. 1, the bar holder 20 is provided below the bar 10 in the Z direction. As shown in FIG. 2, the bar holder 20 extends along the Y direction.

As shown in FIG. 2, the coating liquid L flowing from the storage unit 30 is supplied to the vicinity of the center of the bar holder 20 in the Y direction.

As shown in FIGS. 1 and 3, the bar holder 20 includes a first main body portion 21, a second main body portion 22, a groove portion 23, a flow path 24, a liquid reservoir portion (manifold) 25, and an adjusting portion 26. And have.

The first main body 21 and the second main body 22 have slits S through which the coating liquid L flows. The width of the slit S is determined by the width of the adjusting portion 26. The width of the slit S is not particularly limited, but is preferably 0.05 mm to 2.0 mm. For example, when the width of the slit S is smaller than 0.05 mm, the pressure in the slit S near the center in the Y direction is unintentionally increased by the coating liquid L supplied near the center in the Y direction of the bar holder 20. There is a possibility that the slit S near the center in the Y direction will be deformed and uniform coating to the web W will not be possible. Further, for example, when the width of the slit S is larger than 2.0 mm, the coating liquid L is barred from a substantially central position in the Y direction before the coating liquid L is stored in the liquid reservoir 25, as will be described later. It may be supplied to No. 10 and may not be uniformly applied along the Y direction. The present invention also includes a structure in which the width of the slit S is smaller than 0.05 mm and a structure in which the width of the slit S is larger than 2.0 mm.

The groove portion 23 is provided above the bar holder 20. The bar 10 is arranged in the groove 23 so as to be housed through the gap G. The groove portion 23 is formed so as to extend along the Y direction.

The flow path 24 is formed so as to penetrate the second main body portion 22 along the X direction. The coating liquid L supplied from the storage unit 30 circulates in the order of the flow path 24, the liquid storage unit 25, the slit S, and the groove portion 23, and is supplied to the bar 10.

The liquid reservoir 25 is provided in the first main body 21. The liquid reservoir 25 is formed so as to extend along the Y direction. As shown in FIG. 3, the liquid reservoir 25 is formed in a substantially semicircular shape, but is not limited to this, and may be formed in a substantially rectangular shape. The size of the liquid reservoir 25 is such that when the coating liquid L is supplied from the storage portion 30, the liquid reservoir 25 is first filled with the coating liquid L, and then the slit S is circulated. If there is, there is no particular limitation.

The adjusting unit 26 adjusts the width of the slit S formed between the first main body portion 21 and the second main body portion 22. As shown in FIGS. 1 and 3, the adjusting portion 26 is arranged below the first main body portion 21 and the second main body portion 22.

The coating liquid L is stored in the storage unit 30. The storage unit 30 can store the coating liquid L up to a predetermined liquid level. The coating liquid L stored in the storage unit 30 is sent to the bar holder 20 by the liquid feeding pump 40.

The defoaming filter 50 is provided between the liquid feed pump 40 and the bar holder 20. The air bubbles inside the coating liquid L sent from the storage unit 30 by the liquid feeding pump 40 are reduced by the defoaming filter 50. Specifically, when the coating liquid L supplied to the defoaming filter 50 flows from the lower side to the upper side of the defoaming filter 50, bubbles are separated upward, and the coating liquid L from which the bubbles are separated is a bar holder. It will be distributed toward 20. By providing the defoaming filter 50 in this way, the amount of air bubbles contained in the coating liquid L supplied to the bar 10 is reduced, so that when the coating liquid L is applied to the web W, coating streaks are generated. Can be more preferably suppressed.

Next, the coating method of the coating apparatus 1 according to the present embodiment will be described.

First, the coating liquid L is stored in the storage unit 30. Then, the coating liquid L stored in the storage unit 30 is sent to the bar holder 20 by the liquid feeding pump 40. At this time, the defoaming filter 50 arranged between the storage portion 30 and the bar holder 20 reduces the bubbles contained in the coating liquid L.

Then, the coating liquid L that has passed through the defoaming filter 50 is supplied to the bar holder 20. The coating liquid L supplied to the bar holder 20 flows through the flow path 24 and is sent to the liquid reservoir 25. Then, after the entire area of the liquid reservoir 25 extending along the Y direction is filled with the coating liquid L, the coating liquid L circulates through the slit S in the Z direction in a wall shape along the Y direction.

Then, the coating liquid L that has passed through the slit S flows through the gap G formed between the bar 10 and the bar holder 20, and then a part of the coating liquid L comes into close contact with the outer periphery of the bar 10 and becomes a web W. It is applied. Further, the coating liquid L flows through the gap G formed between the bar 10 and the bar holder 20, and then overflows from the plus side and the minus side of the bar holder 20 in the X direction as shown in FIG.

Here, for example, in the case of coating without overflowing, since the web W is accompanied by the air existing on the surface of the web W, air bubbles are generated when the web W comes into contact with the coating liquid L existing on the surface of the bar 10. It may occur and coating streaks may occur.

On the other hand, in the present embodiment, since the coating liquid L is applied while overflowing from the upstream side (right side in FIG. 3), the air existing on the surface of the web W is removed by the pressure of the liquid feeding. , It is possible to preferably suppress the occurrence of coating streaks.

As described above, the coating device 1 according to the present embodiment includes a bar 10 for applying the coating liquid L to the web W, a slit S through which the coating liquid L flows, and a gap G between the bars 10. It has a bar holder 20 configured so that the coating liquid L flows from below and overflows from above. According to the coating device 1 configured in this way, the coating liquid L distributed from the bar holder 20 is directly applied to the web W by the bar 10 without applying the coating liquid L stored in the liquid pan to the web by the pickup roll. Apply to. Therefore, it is possible to prevent the generation of coating streaks due to air bubbles generated between the web and the pickup roll. Further, since the coating liquid L flows through the gap G between the bar 10 and the bar holder 20 from below and the coating liquid L overflows from above, air bubbles generated between the web W and the bar 10 are suppressed. be able to. From the above, when the coating liquid L is applied to the web W, the occurrence of coating streaks can be suppressed.

Further, the bar holder 20 has a liquid reservoir 25 for storing the coating liquid L along the Y direction. According to the coating device 1 configured in this way, after the coating liquid L is filled in the entire area of the liquid reservoir 25 extending along the Y direction, the coating liquid L is formed into a wall shape along the Y direction. The slit S is circulated in the Z direction. Therefore, it is possible to preferably prevent the coating liquid L from being supplied to the bar 10 from a position substantially at the center in the Y direction, so that the coating liquid L cannot be uniformly applied along the Y direction.

Further, the coating device 1 is provided between the storage unit 30 in which the coating liquid L is stored, the liquid feeding pump 40 that feeds the coating liquid L toward the bar holder 20, and the liquid feeding pump 40 and the bar holder 20. It has a defoaming filter 50 for removing bubbles contained in the coating liquid L. According to the coating device 1 configured in this way, the amount of air bubbles contained in the coating liquid L supplied to the bar 10 is reduced, so that when the coating liquid L is applied to the web W, coating streaks are generated. Can be more preferably suppressed.

Although the coating device 1 according to the present invention has been described above through the embodiments, the present invention is not limited to the configuration described in the embodiments, and can be appropriately modified based on the description of the claims. Is.

For example, in the above-described embodiment, the coating device 1 has the liquid reservoir 25, but the liquid reservoir 25 may not be provided.

1 Coating device,
10 bars,
20 bar holder,
25 Liquid reservoir,
30 Reservoir,
40 Liquid feed pump,
50 defoaming filter,
G gap,
L coating liquid,
S slit,
W Web.

Claims (4)

A bar that applies the coating liquid to the web,
A coating device including a slit through which the coating liquid flows, and a bar holder configured so that the coating liquid flows from below and overflows from above in a gap between the bars. The coating device according to claim 1, wherein the bar holder has a liquid reservoir for storing the coating liquid along the longitudinal direction of the bar holder. A storage unit in which the coating liquid is stored and
A liquid feed pump that feeds the coating liquid toward the bar holder, and
The coating apparatus according to claim 1 or 2, further comprising a defoaming filter provided between the liquid feeding pump and the bar holder to remove bubbles contained in the coating liquid. The coating device according to any one of claims 1 to 3, wherein the width of the slit is 0.05 mm to 2.0 mm.

Images