JP2002086038A - Coating device and coating method - Google Patents

Abstract

(57) [Problem] To provide a coating apparatus and a coating method capable of preventing a liquid pool of a coating liquid from being generated on both side edges of a web. SOLUTION: A web 1 enters a dipping tank 11, and a first coating liquid 21 in the dipping tank 11 is applied to both surfaces of the web 1. On both side edges 2 of the web 1, a second coating liquid 22 having a higher concentration than the first coating liquid 21 is applied over the first coating liquid 21. As a result, the first coating liquid 21
Is pulled toward the second coating liquid 22 so that the inclined portions of the first coating liquid 21 disappear on both side edges 2 of the web 1, thereby preventing the occurrence of a liquid pool on both side edges 2 of the web 1. can do.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coating apparatus and a coating method for applying a coating liquid to a web made of paper or metal, and more particularly to suppressing a liquid pool of the coating liquid on both side edges of the web. The present invention relates to a coating apparatus and a coating method that can perform the coating.

[0002]

2. Description of the Related Art As a method of applying a coating liquid to a web made of paper, metal, or the like, an apparatus having a dip tank containing a coating liquid applied to the web is known.

[0003] When the web enters the dip tank, FIG.
(A) As shown in (b), the coating liquid 20 is applied to both surfaces of the web 1 in the dip tank.

[0004]

As shown in FIG. 3 (a), the coating liquid 20 applied to the web 1 forms an inclined portion 25 on the side edge 2 of the web 1 on both sides of the web 1.
The inclined portion 25 is thinner than other portions of the coating liquid 20 and dries quickly.

When the inclined portion 25 of the coating liquid 20 is dried as described above, the surface tension σ _{SOLID of the} solid dissolved in the coating liquid is generally larger than the surface tension σ _{SOLV of the} solution. The tension becomes larger than the surface tension of the other portions, and the solution flows to the inclined portion 25, so that the liquid pool 20a is formed at the side edge of the web 1.

As described above, the liquid pool 2 is formed on the side edge 2 of the web 1.
When 0a occurs, the film quality of the coating liquid 20 becomes non-uniform or the product quality is deteriorated due to insufficient drying of the liquid pool 20a.

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and it is an object of the present invention to provide a coating apparatus and a coating method capable of reliably suppressing liquid accumulation on both side edges of a web. I do.

[0008]

According to the present invention, there is provided a dip tank in which a web enters and a first coating liquid to be applied to the web is stored, and at least the web is provided downstream of the dip tank in the web running direction. And a pair of application means for applying a second coating liquid having a higher concentration than the first coating liquid to both side edges of the web.

[0009] The present invention comprises a step of applying a first coating liquid to both sides of the web;
Applying a second coating liquid having a higher concentration than the first coating liquid to both side edges thereof.

According to the present invention, the first coating liquid is applied to both sides of the web, and the second coating liquid having a higher concentration than the first coating liquid is further coated on the first coating liquid on both side edges of the web. Is applied. As a result, the first coating liquid can be pulled toward the second coating liquid, and the inclined portions of the first coating liquid can be eliminated on both side edges of the web.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. 1 and 2 are views showing an embodiment of a coating apparatus and a coating method according to the present invention.

1 and 2, a coating apparatus 10 includes a dip tank 11 in which a web 1 enters and a first coating liquid 21 to be applied to the web 1 is stored.
A pair of nozzles (coating means) 13 are provided on one surface side of the web 1 coming out of the nozzle 1 and apply the second coating liquid 22 to both side edges 2 of the web 1. This pair of nozzles 1
3 may be provided on both sides of the web 1, and a total of four nozzles may be provided.

The web 1 is made of paper, plastic, or metal, enters the dip tank 11, and is sent upward. The web 1 that has passed through the pair of nozzles 13 is then sent to a dryer (not shown) to dry the first coating liquid 21 and the second coating liquid 22 on the web 1.

As the first coating liquid 21, PVA or the like is used, and as the second coating liquid 22, PVA or the like having a higher concentration than the first coating liquid 21 is used.

Next, the coating apparatus 10 having the above-described configuration will be described.
A coating method using is described.

First, the web 1 enters the dipping tank 11, and the first coating liquid 21 is applied to both surfaces of the web 1 in the dipping tank 11. First in the dip tank 11
The coating method of the coating liquid 21 is a so-called “dip pickling” method, and the coating liquid 21 can be easily applied onto the web 1. In this case, inclined portions 25 (see FIG. 3A) of the first coating liquid 21 are formed on both side edges 2 of the web 1.

Thereafter, a pair of nozzles 13 is applied to both side edges 2 of the web 1 so as to overlap the first coating
2 is applied. By applying the second coating liquid 22 having a higher concentration than the first coating liquid 21 to both side edges 2 of the web 2 as described above, the first coating liquid 21 is pulled toward the second coating liquid 22. be able to. Therefore, the inclined portions 25 of the first coating liquid 21 are eliminated at both side edges 2 of the web 1, and the second coating liquid 22 can be maintained flat at both side edges 2 of the web 1 (FIG. 2). ).

As described above, at both side edges 2 of the web 1,
Since the inclined portion 25 can be eliminated, the coating liquid on both side edges 2 of the web 1 can be prevented from drying and solidifying, and the liquid pool can be prevented from occurring.

As described above, according to the present embodiment, the first coating liquid can be applied to the web 1 by the dipping tank 11, and the first coating liquid 21 is superimposed on the two side edges 2 of the web 1. The second coating liquid 22 can be applied from the pair of nozzles 13, and the slopes of the coating liquid on both side edges 2 of the web 1 can be eliminated to prevent liquid pooling. For this reason, it is possible to make the film thickness of the coating liquid uniform and prevent the product quality from deteriorating.

[0020]

Next, an embodiment of the present invention will be described. First
The following was used as the coating liquid 21. 1. Coating liquid concentration 10.0 vol% 2. 2. Coating liquid temperature 40.0 ° C 3. Coating liquid viscosity 15.0 cps Coating Liquid Density 1.0 g / ^CM 3 5. Coating speed 1.0 m / min The coating thickness t of the first coating liquid 21 can be obtained by using the equation (1). t = K (ηv / ρg) ^1/2 (1) where K: constant (0.8 for Newtonian fluid), η: viscosity of liquid, v: coating speed, ρ: density of liquid, g: gravitational acceleration Using equation (1), t = 0.8 × (15.0 × 10 ⁻³ × 1.0 / 60 /
(1.0 × 9.8 × 10 ³ ) ^1/2 ≒ 130 μm. In this case, the thickness td at the time of drying is about 13 μm. The application conditions of the second coating liquid 22 at this time are as follows. Concentration 50.0 vol% Coating thickness 26.0 μm (Dry thickness ≒ 13μ
m) Using the first coating liquid 21 and the second coating liquid 22 as described above, without causing liquid accumulation on both side edges 2 of the web 1,
The first coating liquid 21 and the second coating liquid could be applied with high accuracy.

[0021]

As described above, according to the present invention, since the inclined portions of the first coating liquid can be eliminated at both side edges of the web, it is possible to prevent the liquid pool of the coating liquid from being generated. it can. Therefore, the film thickness of the coating liquid can be kept uniform on both side edges of the web.

[Brief description of the drawings]

FIG. 1 is a view showing a coating apparatus according to the present invention.

FIG. 2 is a view showing a first coating liquid and a second coating liquid applied to a web.

FIG. 3 is a view showing a coating liquid applied by a conventional coating method.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Web 2 Side edge 10 Coating apparatus 11 Dip tank 13 A pair of nozzles 21 First coating liquid 22 Second coating liquid

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (reference) B05D 7/00 B05D 7/00 NF term (reference) 4D075 AB03 AB32 AB36 AB38 AE04 AE06 AE19 CA48 DA04 DA34 DB01 DB18 DB31 EA07 EB19 4F040 AA22 AA33 AB04 AC02 AC04 AC08 BA47 CC20 4F042 AA22 AA29 ED01 ED02

Claims (3)

[Claims] 1. A dipping tank in which a web enters and a first coating liquid applied to the web is stored; and a dipping tank is provided at least on one surface side of the web downstream of the dip tank in the web traveling direction. And a pair of application means for applying a second coating liquid having a higher concentration than the first coating liquid to both side edges of the coating apparatus. 2. A coating apparatus according to claim 1, wherein said pair of coating means are provided on both sides of the web. 3. A step of applying a first coating liquid to both sides of the web, and applying a second coating liquid having a higher concentration than the first coating liquid to both side edges of at least one side of the web. A coating method comprising the steps of: