JPH06126229A - Method and device for applying coating liquid - Google Patents

Abstract

PURPOSE:To enable the stable application at a high applying speed in the coating liquid applying device for producing magnetic recording media, etc., by applying a solvent of the same compsn. as the compsn. of a coating material soln. on the coating surface of a web just before a coating material applying stage. CONSTITUTION:A solvent applying work position is set just before the coating material applying work position by the coating material applying device 12 along the traveling line of the traveling web 1 which is unwound from an unwinding section 11 and a solvent applying device 15 is disposed. The solvent applying device 15 constitutes a gravure coating system with a gravure roll 16 and a backup roll 17. The solvent C of the same compsn. as the compsn. of the coating material soln. A is applied on the coating surface of the web 1 by the gravure roll 16. The coating material soln. A is then applied by the coating material applying device 12 on the film of the solvent C. The coating is then dried, by which the magnetic layer is made to remain on the web 1 and is thus formed. The magnetic powder is oriented by a magnet 14 for orientation.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coating method and apparatus suitable for manufacturing magnetic recording media and the like.

[0002]

2. Description of the Related Art Conventionally, in a magnetic recording medium manufacturing line, as described in JP-A-62-117666, a paint coating device is arranged at a paint coating work position along a web running line, and the web is applied by the paint coating device. The magnetic coating solution can be applied to the application surface of.

[0003]

However, in the prior art, the upper limit of the running speed of the web which can be applied while the film thickness of the coating solution is stably supplied to the coating surface of the web by the coating device is relatively low. And the web running speed is 100m
In order to increase the speed to / min or more, the thickness of the magnetic layer formed on the web needs to be 3 μm or more. At this time, if the magnetic layer thickness is less than 3 μm and the web running speed is increased to 100 m / min or more, the thickness of the coating solution supplied to the coating surface of the web becomes too thin and unstable, resulting in good coating. Quality cannot be secured.

An object of the present invention is to enable a stable coating at a high coating speed while reducing the thickness of the coating layer formed on the web.

[0005]

The present invention according to claim 1 is a coating method for coating a coating solution on a coating surface of a web by a coating device, immediately before the coating process by the coating device. The coating surface of the web is coated with a solvent having the same composition as the coating solution.

According to a second aspect of the present invention, the coating material application device is arranged at a coating material application position along the web running line,
In a coating device capable of coating a coating solution on a coating surface of a web by this coating coating device, a solvent coating device is arranged at a solvent coating work position determined immediately before the above-mentioned coating coating work position along the web running line, A coating device allows the coating surface of the web to be coated with a solvent having the same composition as the coating solution.

[0007]

The solvent C having the same composition as the coating solution A (solvent B) is applied to the application surface of the web immediately before the application of the coating solution in the coating application step. Therefore, in the coating material coating step, a thick film in which the film of the solvent C and the film of the coating solution A are laminated on each other is formed on the coating surface of the web, and since the thick film is thick, it is stabilized even at high speed coating. . Therefore, even at the time of high-speed coating, the film thickness of the coating solution supplied in the coating process is sufficient if it occupies a part of the thick film, and the film thickness can be reduced.

After that, the solvent C forming the thick film and the solvent B in the coating solution A are evaporated on the coated surface of the web, and a thin coating layer remains on the web.

[0009] By the above, it is possible to achieve stable coating at a high coating speed while reducing the thickness of the coating layer formed on the web.

In the practice of the present invention, the coating amount of the solvent C is preferably equal to or less than the coating amount of the coating solution A, and more preferably 1/2 to 1/10.

In the practice of the present invention, the coating method of the coating device may be any of an extrusion type method, a gravure method, a reverse method and the like.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a schematic diagram showing a first embodiment, and FIG.
3 is a schematic diagram of the main part of the coating process, FIG. 3 is a model diagram of the coating process, and FIG.
It is a schematic diagram which shows an Example.

(First Embodiment) (Refer to FIGS. 1 to 3) The coating device 10 employs an extrusion-type coating method to obtain a magnetic layer thickness of 1.0.
It manufactures μm magnetic recording media.

In the coating device 10, the coating material coating device 12 is arranged at a coating material coating work position along the running line of the web 1 unwound from the unwinding portion 11, and the web 1 is coated by the extrusion type coating head 13 of the coating device 12. Apply magnetic coating solution A to the surface. Coating solution A contains solvent B.

The coating device 10 is the coating device 1
By the orienting magnet 14 arranged on the outlet side of the coating solution A
A magnetic recording medium is manufactured by orienting the magnetic powder therein, and then drying and winding.

Here, in the coating device 10, the solvent coating work position is set immediately before the paint coating work position by the paint coating device 12 along the traveling line of the web 1, and the solvent coating device is located at this solvent coating work position. 15 are arranged. The solvent coating device 15 is a gravure coating system and includes a gravure roll 16 and a backup roll 17. And
The gravure roll 16 of the solvent application device 15 applies the solvent C having the same composition as the coating solution A to the application surface of the web 1.

Therefore, in the coating material coating device 12, the coating material solution A discharged by the coating head 13 is as shown in FIG.
The solvent coating device 15 coats the film of the solvent C, which has been supplied onto the web 1 in advance.

However, the magnetic recording medium manufacturing process by the coating device 10 will be described in detail below (see FIG. 3).

(A) The solvent coating device 15 coats the coating surface of the web 1 with the solvent C having the same composition as the coating solution A (see FIG. 3).
(See (A)).

(B) The coating solution A is applied on the solvent C of (A) by the coating device 12 (see FIG. 3B).

(C) The coating solution A and the solvent C on the web 1 are dried. The coating solution A and the solvent C are mixed and dried on the web 1 (see FIG. 3C).

(D) After the drying of the above (C), the solvent B and the solvent C in the coating solution A are evaporated, and the magnetic layer D is left on the web 1.

The operation of this embodiment will be described below. The coating surface of the web 1 is coated with a solvent C having the same composition as the coating solution A (solvent B) immediately before the coating solution is coated in the coating step. Therefore, in the coating material application step, a thick film is formed by laminating the film of the solvent C and the film of the coating solution A on the application surface of the web 1, and the thick film is stable even at high speed application because it is thick. To do. Therefore, even at the time of high-speed coating, the film thickness of the coating solution supplied in the coating process is sufficient if it occupies a part of the thick film, and the film thickness can be reduced.

After that, the solvent C forming the thick film and the solvent B in the coating solution A are evaporated on the coated surface of the web 1, and a thin coating layer remains on the web 1.

By the above, the coating layer formed on the web 1 can be made thin, and stable coating can be performed at a high coating speed.

(Second Embodiment) (See FIG. 4) The coating device 20 is different from the coating device 10 in that a gravure coating system is used as the coating device 21 instead of the coating device 12. . Paint application device 21
Includes a gravure roll 22 and a backup roll 23.

Like the coating device 10, the coating device 20 is arranged immediately before the coating material coating device 21.
It is equipped with 5.

Therefore, even in the coating device 20, the magnetic recording medium manufacturing process (see FIG. 3) substantially similar to that of the coating device 10 can be realized, and the same effects as the above-described effects can be obtained.

Thereafter, the magnetic layer thickness is 1.0 by the coating device 20.
Table 1 shows the results of the production of the magnetic recording medium of μm.

In the practice of the present invention, the magnetic coating solution A contains 100 parts of magnetic powder (metal powder), 10 parts of alumina, 1 part of carbon black, 10 parts of vinyl chloride binder, 5 parts of urethane binder and 3 lubricants. Part, curing agent 5 parts, solvent (MEK
: Toluene: Anone = 1: 1: 1) Consisting of 300 parts. Then, magnetic powder, alumina, carbon black, and a binder were kneaded and dispersed, and then a lubricant and a curing agent were added to obtain a paint. The physical properties of this coating are a viscosity of 300 cp.

The examples of Table 1 are those using the above coating device 20, and the comparative examples are those in which the solvent coating device 15 was not used in the above coating device 20. According to the evaluation results of Table 1 in which the coating speed was changed and the coating film state was observed, it is recognized that the present invention enables stable coating at a high coating speed while reducing the thickness of the magnetic layer.

[0032]

[Table 1]

[0033]

As described above, according to the present invention, it is possible to perform stable coating at a high coating speed while reducing the thickness of the coating layer formed on the web.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a first embodiment.

FIG. 2 is a schematic view of a main part of FIG.

FIG. 3 is a model diagram of a coating process.

FIG. 4 is a schematic diagram showing a second embodiment.

[Explanation of symbols]

 1 web 10 coating device 12 paint coating device 15 solvent coating device

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI technical display location G11B 5/842 Z 7303-5D

Claims (2)

[Claims] 1. A coating method for coating a coating solution on a coating surface of a web by a coating device, wherein a solvent having the same composition as the coating solution is coated on the coating surface of the web immediately before the coating step by the coating device. A coating method characterized by: 2. A coating device, wherein a coating material coating device is arranged at a coating material coating work position along a web traveling line, and a coating solution can be coated on the coating surface of the web by the coating material coating device, wherein the coating material along the web traveling line. A solvent coating device is arranged at a solvent coating work position determined immediately before the coating work position, and a solvent having the same composition as the coating solution can be coated on the coating surface of the web by the solvent coating device. .