JPH04193370A - Coating device for discontinuous substrate - Google Patents

Abstract

PURPOSE:To avert the thick coating and infiltration into the rear at the coated part without being restricted by the physical property of a coating soln. by controlling the angle of a corner within 5mm from the line of contact on the upstream side between a suspended member and the substrate to an obtuse angle of >=120 deg. on the surface of the member on which the soln. flows down. CONSTITUTION:A straight line is formed on the upstream side of the line of contact between a solid curtain 5 and a substrate 7, and there is not any corner. A coating soln. being applied is always held in a corner 11, and an excellent application state is obtained at all times. When the curtain 5 turned inside out is used, there is a corner 12 on the upstream side of the line 11 of contact. The angle of the corner 12 is controlled to about 135 deg.. The coating soln. 4 being applied is not held in the corner 12 but held in the corner 11 even in this case, and an excellent application state is obtained. Unless there is not any corner having <=120 deg. angle within 5mm from the line of contact, the coating soln. is held by the line of contact when applied, and an excellent application state is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an apparatus for uniformly applying a single layer or multiple layers of a coating liquid onto the surface of a discontinuous substrate. Specifically, the present invention relates to an apparatus for coating a photographic emulsion onto a short substrate such as a glass plate, an aluminum plate, a zinc plate, or a plastic sheet.

[Problems with conventional technology]

As a method of applying a single layer or multiple layers of coating liquid to a discontinuous substrate, the tip of a liquid injection device is placed above a traveling discontinuous substrate and forms a single layer or multiple layers of coating liquid. A device (hereinafter referred to as a solid curtain coating device) that attaches a flexible, elastic, and water-impermeable hanging member to the substrate and applies the coating liquid flowing down the hanging member onto the substrate by bringing the tip of the hanging member into contact with the substrate. ), a method has been proposed in which a liquid receiver is attached to the lower part of the hanging member so as to be able to freely move up and down, and comes in contact with the tip of the hanging member to assist the flow of the coating liquid. (Japanese Patent Application No. 1-261462, Japanese Patent Application No. 1-325176) However, when coating is performed using this method, depending on the coating conditions, the coating film may not be completely coated from the beginning of the substrate, and the fourth As shown in the figure, the partially uneven smearing sometimes turned into lines.

- For boat fishing, the viscosity and surface tension of the coating solution should be lowered as much as possible to improve the wettability between the coating solution and the substrate, and the timing of separating the component from the hanging member for the liquid receiver should be brought forward to prevent smearing. The uneven coating can be eliminated by increasing the amount of coating liquid held at the tip of the hanging member.

However, the former has the problem that restrictions on the physical properties of the coating liquid are strong and it is difficult to apply it to any desired coating liquid, and the latter has the problem that thick coating and back-covering are likely to occur in areas where the coating is applied.

On the other hand, the inventors have proposed a coating method that solves the problem of coating peeling from the edge or back surface of the substrate as a result of the coating solution being applied to the edge or back surface of the substrate in the solid curtain coating method. Before passing under the substrate, the substrate and the hanging member are maintained in a positional relationship such that they do not come in contact with each other, and after passing under the tip of the substrate or the hanging member, the substrate and the hanging member are brought into contact and coating is started. We proposed a method in which the contact between the substrate and the hanging member is cut off again just before the coating is applied to the end of the substrate. (Patent Application No. 185860/1999) This method is
Compared to the method of coating from the top of the board, there is no need to worry about the coating solution going backwards, and the linearity of the coating line has also been greatly improved. The outbreak could not be completely eliminated.

FIG. 5 shows a single-layer solid curtain coating device using an extrusion type liquid injector 3, and the liquid receiver is mounted so that the device 6 can be moved up and down by a vertical device (not shown). In FIG. 5(1), when no coating is being applied, the liquid receiver device 6 is in the upper position and in contact with the tip of the solid curtain 5, thereby assisting the flow of the coating liquid 4 supplied from the solid curtain 5.

In Fig. 5 (2), the liquid receiver is placed in the device 6 just before the tip of the board.
is separated from the solid curtain 5, and the tip of the substrate begins to come into contact with the solid curtain 5.

Normally, a solid curtain is cut with precision using a guillotine cutter, shear cutter, rotary cutter, knife, etc. so that the contact with the substrate is uniform in the width direction, but the shape of the tip thereof is at right angles unless otherwise intended.

Figures 6 (1) and (2) are enlarged views of the state of the coating liquid at the tip of the solid curtain at the time of application (the state shown in Figure 5 (2)) when a conventional type solid curtain is used. It is something that At the tip of the solid curtain, the coating liquid 4 is held at the corner of the curtain tip, or the coating liquid is held at the lower corner 1) of the curtain tip in FIG. 6 (1) and at the upper corner 12 of the tip in FIG. Indicates a retained state.

As a result of a detailed study of the state of smearing, the inventors found that
In the case of figure (1), good smearing can be obtained, but in the case of figure (1)
In the case of 2), it has been found that immediately after the solid curtain and the substrate come into contact, the coating liquid does not come into contact with the substrate, resulting in poor coating (coating on uneven surfaces shows lines).

[Problem to be solved by the invention]

The inventors analyzed the cause of poor coating (coating on uneven surfaces is a line) and found that the quality of coating is controlled by the state of retention of the coating liquid at the tip of the hanging member. It was discovered that by modifying the shape of the tip of the hanging member, the problem of smearing could be completely eliminated.

An object of the present invention is to solve the above-mentioned problems of the prior art in a method of applying a single layer or multiple layers of a coating liquid to a discontinuous substrate, and to eliminate any restrictions on the physical properties of the coating liquid and to ensure that the coating is not completely coated. The object of the present invention is to provide a coating device that can apply a straight line without causing problems such as thick coating or reverse coating.

[Means and actions to solve the problem]

The above-mentioned object of the present invention is to provide a hanging member having flexibility, elasticity, and water impermeability at the tip of a liquid injector that is disposed above a traveling discontinuous substrate and forms one or more layers of coating liquid. A device for applying a single layer or multiple layers of a coating liquid onto a substrate by attaching a device to the substrate and bringing the tip into contact with the hanging member,
In the discontinuous substrate coating apparatus, the coating liquid of the hanging member is provided with a liquid receiver that is attached to the lower part of the hanging member so as to be freely vertically movable and that assists the flowing down of the coating liquid while being in contact with the tip of the hanging member. The angle of the corner that exists within 5 mm upstream from the contact line between the hanging member and the substrate on the surface is 120
This is achieved by a discontinuous substrate coating device characterized by an obtuse angle of ˚ or more.

Embodiments and functions of the present invention will be explained below using figures.

FIG. 1 shows the state of the coating liquid at the tip of the solid curtain at the time of application (the state shown in FIG. 5 (2)) when using an example of the solid curtain based on the present invention.

In this example, the solid curtain 5 is in contact with the substrate at an angle of 50°, and its tip is not cut at a right angle but at a 45° angle. The contact line between the solid curtain and the substrate is corner 1
).

In this embodiment, the line upstream from the contact line between the solid curtain 5 and the substrate 7 is a straight line and does not have any corners. In this embodiment, as shown in FIG. 1, since the coating liquid during painting is always held in the corner 1), a good coating condition can always be obtained.

FIG. 2 shows an example in which the solid curtain according to the invention shown in FIG. 1 is used upside down. In this case as well, the contact line between the solid curtain 5 and the substrate is the line shown in FIG. 1), but unlike the case in FIG. 1, there is a corner 12 upstream from the contact line.

The angle of corner 12 is 135°. Also in this case, during application, the coating liquid 4 is always held at the corner 1) without being held at the corner 12, so that a good application state is always obtained.

In the experiments conducted by the inventors, it was found that whether or not the coating liquid is retained at the corner on the lower surface of the coating layer flow depends on the physical properties of the coating liquid, the amount of coating liquid fed, the material of the solid curtain, the angle of the solid curtain, and the solid curtain and liquid receiver. Depending on conditions such as the timing of the separation of the equipment, or if there is no corner with an angle smaller than 1200 within 5 mm upstream from the contact line between the solid curtain and the substrate, the application may sometimes occur under any conditions. The liquid is retained in the contact line and a good casing condition can be obtained.

FIG. 3 shows another embodiment of the invention in which the cutting angle of the solid curtain tip at the line of contact with the substrate is a right angle, but the upstream corner is an arc, less than 120°. Since there are no angles, the coating liquid is always held at the corner 1) of the contact line, and a good coating condition can be obtained.

The above explanation is for the case where coating is performed from the top of the board, but the method proposed in Japanese Patent Application No. 185860/1992 (the tube cloth method that creates a part of the uncoated area at the top of the board) also applies to this method. It goes without saying that the invention can be effectively applied.

[Comparative example]

Using the conventional solid curtain cloth device shown in Fig. 5, a glass plate with a length of 50 cm and a thickness of 2 mm, traveling at a speed of 3.0 m/min, was coated with a viscosity of 1° cp and a surface tension of 48 d.
Coating liquid of photographic light-sensitive material of yne/cm is coated with a coating width of 50cm.
The film was coated with a film thickness of 100 μm.

The solid curtain has a length of 20 mm and a thickness of 100 μm.
Using a sheet of T (polyethylene terephthalate),
The cut surface of the solid curtain tip was perpendicular as shown in FIG. Also, the contact angle between the solid curtain and the substrate is 5
It was set to 0°.

The liquid receiver was made of stainless steel and was of a linearly inclined type as shown in FIG.

The liquid receiver is a device in which the tip of the substrate contacts the solid curtain.
It was separated from the solid curtain by mm.

As a result, a coating defect occurred at the beginning of the board, and an unevenness of about 2 mm was generated on the coating line.

〔Example〕

Coating was carried out using the solid curtain coating apparatus of the present invention shown in FIG. The material and size of the solid curtain were the same as in the comparative example, and the tip was cut at 45°. Other coating conditions were the same as in the comparative example.

As a result, a good coating condition was obtained at the beginning of the substrate, and the coating lines were completely straight.

Similarly, when the solid curtain was used upside down as shown in FIG. 2, a good coating line was also obtained.

〔Effect of the invention〕

By using the method of the present invention, that is, by making the corner near the upstream side of the contact line where the solid curtain contacts the substrate into an obtuse angle of 120° or more, the coating liquid flowing to the tip of the solid curtain is always held at the contact line. It becomes possible to obtain stable smearing.

[Brief explanation of the drawing]

FIG. 1 is an enlarged view of the state of the coating liquid at the tip of the solid curtain when the solid curtain according to the present invention is applied. FIG. 2 is an enlarged view of the state of the coating liquid at the tip of the solid curtain when the solid curtain according to the present invention shown in FIG. 1 is used upside down. FIG. 3 is another embodiment of a solid curtain according to the present invention. FIG. 4 is a schematic diagram showing the state of defective coating on the coated substrate. FIG. 5 shows a single layer solid curtain coating device using an extrusion type liquid injector. FIG. 5(1) shows the state without application, and FIG. 5(2) shows the state with application. FIGS. 6(1) and 6(2) are enlarged views of the state of the coating liquid at the tip of the solid curtain when a conventional type solid curtain is used. l...Substrate after coating, 2...Roller for substrate conveyance, 3
...Liquid injector, 4...Coating liquid, 5...Solid curtain, 6...Liquid receiver is device, 7...Substrate before coating, 8...
・Poor coating is part 9...paint film, 1). 12... Solid curtain tip corner. Fig. 3/ / Fig. 4/ (j? 5th (f) 6t (riwa)

Claims (1)

[Claims] (1) Attach a flexible, elastic, and water-impermeable hanging member to the tip of a liquid injector that is placed above a traveling discontinuous substrate and forms one or more layers of coating liquid; A device for coating a substrate with a single layer or multiple layers of a coating liquid that flows down on a hanging member in contact with the tip thereof; In a discontinuous substrate coating device equipped with a liquid receiving device that assists the flow down, on the surface of the hanging member on which the coating liquid flows, 5 mm upstream from the contact line between the hanging member and the substrate.
1. A discontinuous substrate coating apparatus, characterized in that the angles of corners existing within the range are obtuse angles of 120° or more.