JPH06170313A - Application method with bar and apparatus - Google Patents

Abstract

PURPOSE:To facilitate the adjustment of film thickness by arranging a bar to be slanted toward the upstream side or the downstream side from the web width direction in the method in which coating liquid is applied on a web and its excessive part is scraped off by the bar. CONSTITUTION:In an applicator in which after coating liquid 3 in a vat 2 is applied on a web driven by an applictor roll 1, the coating layer 5 is scraped by a bar 6 set on a bar support member 7 to obtain desired film thickness, the bar 6 is set so that the angle alpha between it and the web width direction 15 adjustable and the film thickness can be changed by adjusting the angle. The wet film thickness obtained when the bar 6 is contacted to the coating layer 5 (width 1) perpendicularly to the coating advance direction is hw1, while that obtained when the bar 6 is slanted by the angle alpha is hw2; the film thickness hw2 can be calculated from the equation of hw2=hw1X(1/cosalpha).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bar coating method and a coating apparatus, and more particularly to a bar coating method and a coating apparatus whose film thickness can be easily adjusted.

[0002]

BACKGROUND OF THE INVENTION Various types of coating devices are known. For example, dip coating, roller coating, fan-ten coating, air knife, blade coating, bar coating, slide hopper and the like.

In the bar coating method among these coating apparatuses, after coating (transferring) the coating liquid on the web, the excess coating liquid is stopped or scraped off by a bar rotating in the direction opposite to the web to obtain a desired film thickness. It is a device to obtain.

Each of the above-mentioned coating devices can be used as a method for coating an excess coating liquid, but when combined with a bar coating device, each device such as dip coating, roller coating, and fan-ten coating is generally used. Used. It is also possible to use a coating device integrated with the bar coating device.

The bar coating apparatus is widely used because it can apply thin films at high speed with a simple apparatus and operation. As such a bar coating device, for example, the device disclosed in Japanese Patent Publication No. 58-4589 or 59-32190 is known.

The bar used in the bar coating device is generally 0.07 to 1.0 mm around a bar (rod) having an outer diameter of 6 to 25 mm.
A wire of about the same thickness, for example, a piano wire or a stainless steel wire, is densely wound, but a bar having grooves of a certain depth at a certain pitch may also be used.

Such a bar coating device is disclosed in, for example, Japanese Patent Publication Nos. 58-4589 and 59-32190. In these bar coating methods, the coating thickness is generally adjusted by changing the wire diameter. That is, the thinner the diameter of the wire wound around the bar, the smaller the coating amount, and the thicker the diameter, the larger the coating amount.

However, in such a method, when changing a desired film thickness, it is necessary to replace the bar each time, and accordingly, work such as replacement and cleaning is required, which is a top-down work and a lot of work is required. There was a problem that a bar was required and it was expensive.

[0009]

SUMMARY OF THE INVENTION In order to solve the above problems, it is an object of the present invention to provide a bar coating method and apparatus capable of adjusting the film thickness, which does not require bar replacement and subsequent replacement and cleaning work. To provide.

[0010]

The above object of the present invention is to apply a bar coating to obtain a desired film thickness by transferring an excessive amount of coating solution onto a web and scraping off the excessive amount of the solution with a rotating or stationary bar. In the method, the bar is applied along the web surface with an angle α inclined from the width direction of the web to the upstream side or the downstream side.

The present invention will be specifically described below.

FIG. 3 is a sectional view of a conventionally known bar coating device.

FIG. 1A shows a general bar coating device. The coating liquid 3 in the coating liquid vat 2 is applied to the running web 4 by the applicator roll 1 by a dip coater. The coating layer 5 is scraped off to a desired film thickness by the bar 6 set on the bar supporting member 7.
In this case, the bar is slowly rotated in the opposite direction of the web.

Further, FIG. 1B shows an apparatus capable of integrally coating and scraping the coating liquid.

The bar 6 set on the bar support member 7 rotates in the same direction as the running web 4. The coating liquid 3 is supplied from a liquid supply port 8 provided in the bar support member 7 into a guide groove 10 formed between the coating liquid 3 and the dam member 9, and is picked up by a rotating bar to form a liquid pool 11. This is a device for applying a desired film thickness with a bar.

FIG. 2 is an explanatory sectional view of the bar. In the same figure (a), the wire 6a is wound around the bar 6. Reference numeral 5 denotes a web, and the coating amount is defined by a line connecting the peaks of the convex portions in each cross section, that is, a space A indicated by a diagonal line formed between the web and the wire as shown in FIG. .

The diameter of the bar is generally 6 to 25 mm, preferably 6 to 15 mm. The diameter of the wire is 0.07 to 1.0 mm, preferably 0.07 to 0.4 mm. The wire material is corrosion resistant,
Stainless steel is suitable from the viewpoint of wear resistance and strength.

In such a bar coating apparatus, it is necessary to replace the bar when changing the film thickness, which requires time and labor for replacement and cleaning.

The present invention provides a technique for easily controlling the film thickness with respect to such a problem. That is, when the coating liquid is scraped off by a rotating or stationary bar after applying an excessive amount of the coating liquid on the web, the film thickness is changed by adjusting the angle of the bar with respect to the web.

FIG. 1 is an explanatory view of the film thickness changing method of the present invention. In the figure, the wet film thickness obtained by applying the bar 6 to the coating layer 5 having the coating width 1 perpendicularly to the coating advancing direction as in normal coating is hw1, and the bar is the width direction along the web surface. From the above, if the film thickness obtained by inclining at an angle α to the upstream side or the downstream side is hw2, the following relationship holds and the film thickness can be adjusted with only one bar.

Hw2 = hw1 × (1 / cos α) For example, when hw1 = 4 μm and α = 37 °, hw2 = 5 μm
Therefore, it is possible to increase the film thickness by about 25%.

As described above with reference to FIG. 2B, the coating amount that determines the film thickness is determined by the space between the bar and the web. That is, it depends on the length of the bar contacting the web.

There is no particular limitation on the method of changing the angle of the bar. For example, there is a method in which one end is rotatably fixed and the other end is slidable on the rail so that the bar can be fixed at a desired position. For example, one example is shown in FIG.

FIG. 4 is an explanatory view of the bar angle adjusting device. In the figure, the angle of the bar 6 with respect to the web 4 is set by the rotary drive device 12 using the tilt angle adjusting rotary shaft 13 as a fulcrum, and the other end of the bar runs on the arc-shaped rail 15 and the angle α is desired by the fixing screw 14. Fix it at the angle.

In the bar coating of the present invention, the coating liquid used is not particularly limited, and a water or organic solvent liquid of a polymer compound, a pigment aqueous dispersion liquid, a colloidal solution or the like can be applied. Further, the physical properties of the coating solution are not particularly limited, but the viscosity is preferably 100 cp or less.
It is preferably yne / cm or less.

There is no particular limitation on the material, thickness, etc. of the web used in the present invention.

Other conditions generally applied to bar coating can be applied without any special limitation.

[0028]

EXAMPLES Hereinafter, the effects of the present invention will be specifically illustrated by examples.

Example 1 An excessive amount of a coating solution having the following composition was coated on a web by a roller coating method at a coating speed of 40 m / min, and a bar wound with a wire having a diameter of 0.1 mm was applied to the web in a direction perpendicular to the coating direction. When applied over the surface, a coating having a wet film thickness of 8.2 μm was obtained. When this bar was applied at an angle of 26 ° from the width direction to the upstream side along the web surface, the wet film thickness was obtained.
A 9.1 μm coating was obtained and the same bar could be used to increase the film thickness.

(Composition of coating liquid) Methyl ethyl ketone (MEK) 80 parts by weight Cyclohexanone 10 parts by weight Pigment MEK dispersion 5 parts by weight Styrene acrylic resin 5 parts by weight

[0031]

As described above, according to the present invention, it is possible to provide a bar coating method and apparatus capable of adjusting the film thickness, which does not require bar replacement and the accompanying replacement and cleaning work when changing the film thickness.

[Brief description of drawings]

FIG. 1 is an explanatory view of a bar coating device of the present invention.

FIG. 2 is an explanatory diagram of bar coating.

FIG. 3 is a sectional view of a bar coating device.

FIG. 4 is an explanatory view of a bar angle adjusting device.

[Explanation of symbols]

 1 Applicator Roll 2 Coating Liquid Vat 3 Coating Liquid 4 Web 5 Coating Layer 6 Bar 7 Supporting Member 8 Liquid Feeding Port 9 Weir Member 10 Guide Groove 11 Liquid Reservoir 12 Bar Rotation Drive Unit 13 Rotation Shaft for Adjusting Tilt Angle 14 Fixing Screw 15 Yen Arc rail

Claims (2)

[Claims] 1. A bar coating method for obtaining a desired film thickness by transferring an excessive amount of a coating liquid onto a web and scraping off the excessive amount of the liquid with a rotating or stationary bar to obtain a desired film thickness. A coating method in which the coating is performed by inclining at an angle α from the width direction of the web toward the upstream side or the downstream side. 2. A coating apparatus using the coating method according to claim 1.