JP6973211B2 - How to manufacture doctor chamber coater and coated material - Google Patents

Description

The present invention relates to a doctor chamber coater for applying a coating liquid to an object to be coated and a method for manufacturing the coated object.

Examples of this type of doctor chamber coater that have been conventionally used include the configurations shown in Patent Document 1 and the like below. That is, in the conventional configuration, ink (coating liquid) is supplied from the ink tank to the internal space of the doctor chamber through the ink supply path, and the ink adhered to the peripheral surface of the roll body arranged so as to face the internal space of the doctor chamber. Is applied to the object to be coated.

Japanese Unexamined Patent Publication No. 8-58069

When an attempt was made to apply a coating liquid containing an insoluble matter such as a pigment or an aggregate to the object to be coated using the conventional doctor chamber coater as described above, the insoluble matter appeared on the surface of the object to be coated. It sometimes adhered unevenly. As a result of investigating the cause, it was found that the insoluble matter settled inside the doctor chamber, and when the settled insoluble matter soared up, it adhered to the roll body.

The present invention has been made to solve the above-mentioned problems, and an object thereof is a doctor chamber coater and a coated object that can reduce the possibility of uneven adhesion of insoluble matter to the surface of the object to be coated. Is to provide a manufacturing method for.

The doctor chamber coater according to the present invention is a doctor chamber coater that applies a coating liquid containing an insoluble matter to an object to be coated, and is a chamber body, an upper doctor blade extending from the upper part of the chamber body, and a chamber body. A peripheral surface thrusts into the tip of the upper and lower doctor blades, as well as the doctor chamber with an opening defined by the gap between the upper and lower doctor blade tips, as well as the lower doctor blade extending from the bottom of the. The doctor chamber is provided with a roll body arranged to be hit and the peripheral surface faces the inside of the doctor chamber through the opening, and the doctor chamber extends axially below the inside of the doctor chamber. Further, it has a mixing rod that agitates the coating liquid in the doctor chamber by being driven to rotate.

Further, the method for manufacturing a coated object according to the present invention includes applying a coating liquid to the object to be coated by using the above-mentioned doctor chamber coater.

According to the method for manufacturing a doctor chamber coater and a coated product of the present invention, a mixing rod extending in the axial direction of the roll body is rotationally driven on the lower side inside the doctor chamber to drive the coating liquid in the doctor chamber. Is stirred, so that the possibility that the insoluble matter adheres unevenly to the surface of the object to be coated can be reduced.

It is a block diagram which shows the doctor chamber coater by embodiment of this invention. It is a rear view which shows the doctor chamber of FIG.

Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.
Embodiment FIG. 1 is a block diagram showing a doctor chamber coater 1 according to an embodiment of the present invention, and is a cross-sectional view of the doctor chamber 2 along the line AA of FIG. FIG. 2 is a rear view showing the doctor chamber 2 of FIG. The doctor chamber coater 1 shown in FIG. 1 is a facility for applying a coating liquid 1a containing an insoluble matter to an object to be coated. The insoluble matter is, for example, a pigment or an aggregate, which is dispersed without being dissolved in a solvent. Examples of the object to be coated include a strip-shaped member made of a material such as paper, plastic or metal.

As shown in FIGS. 1 and 2, the doctor chamber coater 1 includes a doctor chamber 2 and a roll body 3.

The doctor chamber 2 is a container body in which the coating liquid 1a is stored. An opening 2a is formed in the front portion of the doctor chamber 2. The roll body 3 is arranged so that the peripheral surface faces the inside of the doctor chamber 2 through the opening 2a. When the roll body 3 is rotationally driven, the coating liquid 1a in the doctor chamber 2 sequentially adheres to the peripheral surface of the roll body 3. The coating liquid 1a adhering to the peripheral surface of the roll body 3 is applied to the object to be coated. Another roll may be interposed between the roll body 3 and the object to be coated, or the coating liquid 1a may be directly applied from the roll body 3 to the object to be coated.

The doctor chamber 2 includes a chamber body 20, an upstream doctor blade 21, a downstream doctor blade 22, and a mixing rod 23.

The chamber body 20 is a member having a substantially C-shaped cross section. A supply path 4 and a discharge path 5 are attached to the chamber main body 20. As particularly shown in FIG. 2, the supply path 4 is arranged in the lower center of the chamber body 20 in the width direction 20w (axial direction of the roll body 3). The discharge passage 5 is arranged in the upper portions on both sides of the chamber main body 20 in the width direction 20w. The coating liquid 1a is supplied from the supply passage 4 to the inside of the doctor chamber 2, and the coating liquid 1a accumulated inside the doctor chamber 2 up to the height of the discharge passage 5 is discharged from the discharge passage 5.

The upstream doctor blade 21 is a longitudinal member arranged on the upstream side of the opening 2a related to the rotation direction of the roll body 3. Similarly, the downstream doctor blade 22 is a longitudinal member arranged on the downstream side of the opening 2a related to the rotation direction of the roll body 3. The opening 2a of the doctor chamber 2 can be defined by the gap between the tips of the upstream doctor blade 21 and the downstream doctor blade 22.

The upstream doctor blade 21 constitutes an upper doctor blade extending from the upper part of the chamber main body 20 so that the tip thereof is abutted against the peripheral surface of the roll body 3. Similarly, the downstream side doctor blade 22 constitutes a lower doctor blade extending from the lower part of the chamber main body 20 so that the tip thereof is abutted against the peripheral surface of the roll body 3. The lower doctor blade is a doctor blade arranged on the side where the insoluble matter settles as described later. Since the tips of the blades 21 and 22 are abutted against the peripheral surface of the roll body 3, the inside of the chamber body 20 is a space surrounded as a whole.

Although not shown, a recess is formed on the peripheral surface of the roll body 3. The downstream side doctor blade 22 scrapes the coating liquid 1a adhering to the peripheral surface of the roll body 3 so as to leave the coating liquid 1a in the recess. As a result, a certain amount of the coating liquid 1a remains on the peripheral surface of the roll body 3.

The angle θ in the doctor chamber 2 between the extending direction of the downstream doctor blade 22 and the tangent line of the roll body 3 is set to be less than 90 °. By setting this angle θ to less than 90 °, the force (doctor pressure) at which the tip of the downstream side doctor blade 22 is pressed against the peripheral surface of the roll body 3 becomes large, and the downstream side doctor blade 22 scratches the coating liquid 1a. You can take it more reliably. As will be described later, it is preferable that the angle θ in the doctor chamber 2 between the extending direction of the downstream doctor blade 22 and the tangent line of the roll body 3 is 40 ° or more and 60 ° or less.

The mixing rod 23 is a longitudinal member extending in the axial direction of the roll body 3 (20w in the width direction of the chamber body 20) on the lower side inside the doctor chamber 2. An actuator (not shown) is connected to the mixing rod 23, and the mixing rod 23 is rotationally driven by the driving force of the actuator. By rotationally driving the mixing rod 23, the coating liquid 1a in the doctor chamber 2 is agitated.

As described above, the coating liquid 1a contains an insoluble matter. This insoluble material may settle in the doctor chamber 2. The insoluble matter is settled when the flow of the coating liquid 1a in the doctor chamber 2 is small, for example, when the rotation speed of the roll body 3 is slow or when the supply amount of the coating liquid 1a from the supply path 4 is small. It can happen. By stirring the coating liquid 1a with the mixing rod 23, the sedimentation of the insoluble matter is suppressed, and the possibility that the insoluble matter adheres unevenly to the surface of the object to be coated can be reduced. The mixing rod 23 may be rotationally driven at all times, or may be rotationally driven when the rotational speed of the roll body 3 or the supply amount of the coating liquid 1a from the supply path 4 is smaller than a predetermined value.

Further, as described above, in the present embodiment, the angle θ in the doctor chamber 2 between the extending direction of the downstream doctor blade 22 and the tangent line of the roll body 3 is set to be less than 90 °. Therefore, as compared with the case where the angle θ is 90 ° or more, the space under the inside of the doctor chamber 2 is wider, and the insoluble matter is likely to settle. Stirring the coating liquid 1a with the mixing rod 23 is particularly useful for configurations where the angle θ is less than 90 °.

The mixing rod 23 of the present embodiment is composed of a cylindrical member having a circular cross section. In other words, no protrusion is formed on the outer peripheral surface of the mixing rod 23. Since the mixing rod 23 is a cylindrical member, the coating liquid 1a is excessively agitated to prevent bubbles from being generated in the doctor chamber 2. The generation of foam can cause poor coating. Since the mixing rod 23 is a cylindrical member, it is possible to reduce the amount of coating liquid remaining in the gaps and dents, and the mixing rod can be cleaned more easily. However, the outer shape of the mixing rod 23 can be changed according to the required characteristics, and the mixing rod 23 is, for example, a member having a plurality of wing plates extending in the radial and axial directions from the outer surface of the cylindrical member. , Other configurations are also possible.

The method for producing a coated object according to the present embodiment includes applying the coating liquid 1a to the object to be coated by using the above-mentioned doctor chamber coater 1.

Next, an example will be given. In the doctor chamber coater 1 shown in FIGS. 1 and 2, the present inventor changes the angle θ in the doctor chamber 2 between the extending direction of the downstream doctor blade 22 and the tangent line of the roll body 3 to cause liquid leakage. In addition, the presence or absence of scraping defects in the coating liquid 1a was investigated. As the coating liquid 1a, a liquid having a high viscosity of about 140 s (# 4 Ford cup viscosity) was used. The results are shown in the table below.

When the above-mentioned angle θ was less than 40 °, poor scraping of the coating liquid 1a by the downstream doctor blade 22 occurred. When a scraping defect occurs, the coating liquid 1a adheres to the outside of the cell formed on the surface of the roll body 3 (gravure roll), so that it becomes difficult to control the coating amount of the coating liquid 1a. On the other hand, when the angle θ exceeds 60 °, the paint adheres to the back side (the surface where the coating liquid 1a does not contact) of the downstream side doctor blade 22, and the roll body 3 and the downstream side doctor use the adhered paint as a base point. Liquid leakage occurs with the blade 22. From these results, it was found that the angle θ in the doctor chamber 2 between the extending direction of the downstream doctor blade 22 and the tangent line of the roll body 3 is preferably 40 ° or more and 60 ° or less.

In such a method of manufacturing the doctor chamber coater 1 and the coated material, the mixing rod 23 extending in the axial direction of the roll body 3 is rotationally driven on the lower side inside the doctor chamber 2 in the doctor chamber 2. Since the coating liquid 1a is agitated, it is possible to reduce the possibility that insoluble matter adheres unevenly to the surface of the object to be coated. This configuration is particularly useful for configurations where the angle θ in the doctor chamber 2 between the extending direction of the downstream doctor blade 22 and the tangent of the roll body 3 is less than 90 °.

Further, since the mixing rod 23 is a cylindrical member, the coating liquid 1a can be appropriately agitated, and the generation of bubbles in the doctor chamber 2 can be suppressed.

1 Doctor chamber coater 1a Coating liquid 2 Doctor chamber 2a Opening 3 Roll body 22 Downstream side doctor blade (lower doctor blade)
23 Mixing rod

Claims (5)

A doctor chamber coater that applies a coating liquid containing insoluble matter to the object to be coated.
The opening defined by the chamber body, the upper doctor blade extending from the top of the chamber body, the lower doctor blade extending from the lower part of the chamber body, and the gap between the tips of the upper and lower doctor blades. A doctor chamber with a part and
The roll body is arranged so that the peripheral surface is abutted against the tips of the upper doctor blade and the lower doctor blade, and the peripheral surface faces the inside of the doctor chamber through the opening.
The doctor chamber further has a mixing rod extending in the axial direction of the roll body on the lower side inside the doctor chamber and rotating to stir the coating liquid in the doctor chamber. Yes,
Doctor chamber coater. The doctor chamber has a chamber body and a lower doctor blade extending from the lower part of the chamber body so that its tip abuts against the peripheral surface of the roll body.
The angle in the doctor chamber between the extending direction of the lower doctor blade and the tangent of the roll body is less than 90 °.
The doctor chamber coater according to claim 1. The angle is 40 ° or more and 60 ° or less.
The doctor chamber coater according to claim 2. The mixing rod is a cylindrical member.
The doctor chamber coater according to any one of claims 1 to 3. A method for manufacturing a coated object, which comprises applying a coating liquid to the object to be coated by using the doctor chamber coater according to any one of claims 1 to 4.

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