JPH09201559A - Coating apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To freely control film thickness only by arranging a simple coating head to an existing coating apparatus and to prevent strike-through in dip coating by setting a dip part to a coating head system and further applying a curved surface to the dip part. SOLUTION: A back roll 5 can be more reduced in its width by setting a dip part 5 to a coating head system and an amt. of a coating soln. can be minimized by providing the dip part 3 with a curved surface and the undulation of a liquid surface is suppressed to develop action accurately keeping surface height and, by changing either one of the concn. of the coating soln. and a coating speed, film thickness can be accurately controlled and a higher-grade coating film is obtained. The curved surface of the dip part 3 of a coating head 4 is pref. a curved surface having a diameter the same as or more than that of the back roll 5 and, in order to more well develop effect, the curved surface having the same diameter as the back roll 5 is pref.

Description

Detailed Description of the Invention

[0001]

The present invention relates to a film thickness of, for example, 0.
The present invention relates to a coating device that can be easily controlled in the range of 1 to 30 μm and that can obtain a high-quality coating film.

[0002]

2. Description of the Related Art Conventionally, as a thin film coating apparatus, various coating methods such as a micro gravure coater and a lip coater can be mentioned, but the coating apparatus requires enormous initial cost,
Moreover, since the coating accuracy is required, maintenance of the process is difficult. Furthermore, the width of the coating film thickness is 0.1 to 30 μm
Even in the case of a large change from the ultra-thin film to the normal film thickness as described above, there is a large limit to the free control, so that it is inflexible. The conventional single roll dip coat (also called bead coat)
Is a method of directly coating a film with a rotating roll, and there has been a big problem of back-transfer of the coating liquid onto the back roll and the back surface of the film.

[0003]

The present invention requires an expensive new coater head even when the thickness of the coating film is greatly changed from an ultrathin film to a normal film thickness such as 0.1 to 30 μm. Instead, the objective is to develop a coating device that allows the film thickness to be controlled freely by simply installing a simple coating head on the existing coating device and does not set off with dip coating.

[0004]

DISCLOSURE OF THE INVENTION As a result of intensive studies in view of the above, the present inventors have made a coating head system for the dip portion, and further, by forming a curved surface on the dip portion, 0.1 μm like an antireflection coat. When film thickness control is required, it is 3.5 ~ 5μ like anti-glare coat.
Even in the case of a film thickness of m, it was found that the film thickness can be accurately controlled by changing either the coating liquid concentration or the coating speed, and a high quality coating film can be obtained. completed. That is, the present invention relates to (1) a single roll dip coater, wherein the dip portion is a coating head system, and the dip portion has a curved surface, and (2) the curved surface is a back surface. The coating device according to (1), which is a curved surface having the same diameter as the roll diameter of the roll, and (3) the supply part of the coating liquid is present at the bottom of the dip coater head ( 1) or (2) coating device, (4) (1) through (3) while the coating liquid is supplied to the dip coater head of the coating device, the width of the dip portion of the head is wider. A coating method for a film, characterized in that the coating liquid is applied to the film by the head, (5) a coating liquid supply system is a head (gravity)
The present invention relates to (4) a film coating method, which is a supply method.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION The coating apparatus of the present invention is characterized in that in a single roll dip coater, the dip portion is of a coating head type and the dip portion has a curved surface. In the conventional type dip coater, since the dip part is a dish-shaped container, the dip part is wider than the back roll width, and the settling of the coating liquid is inevitable. The height of the surface cannot be accurately maintained due to the fluctuation of the liquid surface due to the liquid to be generated and the corrugation of the liquid surface, etc., and it has been difficult to obtain a highly accurate coating film surface. In the present invention, the width of the dip portion can be made narrower than that of the back roll by using the coating head system, and the dip portion can have a curved surface to minimize the amount of coating liquid. It has the effect of being pressed down to maintain the height of the surface accurately.By changing either the coating liquid concentration or the coating speed, the film thickness can be controlled accurately, and a higher quality coating film can be obtained. The effect of being able to be played. The curved surface of the dip portion of the coating head used in the present invention is not particularly limited, but it is preferable that the curved surface has a diameter equal to or larger than the roll diameter of the back roll, in order to exert the above effects better. Is preferably a curved surface having the same diameter (R) as the roll diameter of the back roll.

An example of a dip coater head in the coating apparatus of the present invention is shown in FIG. In FIG. 1, a dip coater head 4 has a dip portion 3 having a curved surface having the same R as the roll diameter of the back roll 5, a liquid supply port 1 provided at the bottom of the dip coater head, and an overflow as a recovery portion for excessive supply liquid It is composed of the liquid recovery unit 2.

Next, in order to apply the coating liquid to the film using the coating apparatus of the present invention, first, the resin solid content according to the coating weight after drying (0.1 to 30 g / m ² ). The coating solution having the specified concentration is left to stand to defoam. Next, while supplying this coating liquid to the coater head section in the coating apparatus of the present invention, the film is brought into contact with the dip section in the coating apparatus of the present invention at a predetermined coating speed (for example, 20 m / min or less). Just do it. The film used here is not particularly limited, but a transparent film is preferable. Examples of the material include polyester resins, acetate resins, polycarbonate resins, acrylic resins, polyolefin resins and the like. It is preferable that the width is wider than the width of the coater head, because there is no problem of set-off of the coating liquid. Further, the coating liquid is not particularly limited, and examples thereof include a UV curable resin, a thermosetting resin monomer, a diluting liquid with an organic solvent, and the like. The viscosity is preferably 40 cp or less, and the solid content in the coating liquid is preferably 35% or less.

As for the method of supplying the coating liquid, it is not necessary to supply the coating liquid in excess if the amount consumed for the coating can be replenished, so that the head (gravity) supply method can be sufficiently applied. Since the amount of coating liquid is large in the conventional method, power is usually used to supply the coating liquid.Therefore, drive parts are made explosion-proof or air-driven by using dangerous substances such as organic solvents. It is necessary not only to be economical but also to manage safety aspects. Since the coater head of the present invention does not require a complicated structure, it is possible to reduce the resistance portion, and the head supply method can be sufficiently applied as described above, and the coating liquid can be supplied more easily than the conventional method. it can.

In the present invention, the film thickness can be easily controlled by changing either one or both of the coating liquid concentration and the coating speed, so that the thickness of 0.1 μm such as an antireflection coating can be obtained.
The ultra-thin film of m can be applied to ordinary coatings on the order of a few microns.

In order to reduce the quality of the coating film due to pulsation of the supply liquid, the coating liquid supply unit is arranged at the bottom of the coater head, and the coating liquid is supplied by the head (gravity) supply system. By doing so, by making it possible to easily finely adjust the clearance between the coater head and the coating substrate,
The quality of the coating film can be maintained. Similar to the conventional coating apparatus, defoaming requires sufficient consideration to maintain the quality of the coating film.

[0011]

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples.

Example 1 A 2% solution (solvent: Fluorinert FC75; 3M) of a low refractive index fluorine-based polymer (Teflon AF Dyupon Co., Ltd.)
Using a coating device of the present invention.
It was coated on a 100 μm polyester film at 5 m / min and dried. As a result of measuring the reflectance with an integrating sphere method of a spectrophotometer, the reflectance at 550 nm was 0.55%. Teflon AF has a refractive index of 1.30 and 0.1 μ
It can be seen that the coating has a thickness of m.

Example 2 Ultraviolet curing type hard coating agent (manufactured by Nippon Kayaku Co., Ltd.)
180 μm by changing the concentration of 15% to 35% (solvent: toluene) and the coating speed in the range of 5.0 to 15.0 m / min.
Coated on a polyester film of. The results of the film thickness, the coating solution concentration, and the coating speed are shown in Table 1. The unit of film thickness in Table 1 is μm.

[0014]

[Table 1] Table 1 Coating speed (m / min) 5.0 7.5 10.0 10.0 15.0 Coating solution concentration Film thickness Film thickness Film thickness 15% 2.4 2.8 4.4 5.0 20% 3.4 4.8 6.0 11.0 25% 5.2 7.8 9.6 12.0 30% 7.6 10.6 11.8 19.3 35% 9.5 14.3 17.5 29.0

It can be seen from Table 1 that the film thickness can be easily controlled by changing the concentration of the coating liquid or the coating speed.

[0015]

According to the present invention, in a single roll dip coater, the dip portion is of a coating head type, and the dip portion is curved to change either the concentration of the coating liquid or the coating speed. With this simple operation, the film thickness can be controlled with high accuracy, and a high-quality coating film can be obtained. Therefore, it can be applied to various applications such as when an anti-reflection coating needs a film thickness control of 0.1 μm and further when an anti-glare coating has a film thickness of 3.5 to 5 μm.

[Brief description of drawings]

FIG. 1 is a schematic perspective view of a coater head portion of the present invention.

FIG. 2 is a diagram showing a coating state on a film using the coating apparatus of the present invention.

[Explanation of symbols]

 1 Liquid supply port 2 Overflow liquid recovery unit 3 Dip unit 4 Dip coater head 5 Back roll

Claims (5)

[Claims] 1. A single-roll dip coater, wherein the dip portion is of a coating head type, and the dip portion has a curved surface. 2. The coating apparatus according to claim 1, wherein the curved surface is a curved surface having the same diameter as the roll diameter of the back roll. 3. The coating apparatus according to claim 1, wherein the coating liquid supply section is present at the bottom of the dip coater head. 4. The coating liquid is supplied to a dip coater head of the coating apparatus according to claim 1, and the coating liquid is applied to a film wider than the dip portion of the head. A method for coating a film, characterized in that 5. The method for coating a film according to claim 4, wherein the system for supplying the coating liquid is a head (gravity) supplying system.