JPH10328596A - Transfer type double side coating method and device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To uniformalize the pressure of a fed coating film to form stable coating films on both the surfaces of a web by transferring a coasting film having a fixed film thickness which has passed a resin dam and is formed on coating rolls to both the surfaces of the web at the same time. SOLUTION: Outside the clearances between coating rolls 13 for forming transfer films 12 and doctor rolls 16, resin dams 24 are arranged. When forming the coating films 12 each on both the surfaces of a metallic sheet 1, the clearance between the coating rolls 13, 13 is made equal to the thickness of the metallic sheet 1 plus about 10 μm. The coating films 12 whose film thickness is determined by the doctor rolls 16 above the coating rolls 13 are once moved downward following the rotation of the coating rolls 13 revolving in the engaged direction with each other, and is fed to the metallic sheet 1 travelling upward between the coating rolls 13 from the right and left directions at the same time, and once faces the clearances between the metallic sheet 1 and the coating rolls 13, and then, is translated to the surfaces of the metallic sheet 1 to perform transfer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a double-sided coating method and apparatus for simultaneously forming a resin coating film on both sides of an upwardly running web, and includes a film, a cloth, a paper, a foil, a punching plate, a mesh sheet material and the like. Used to form a coating film on

[0002]

2. Description of the Related Art As this type of double-side coating apparatus, for example, the one shown in FIGS. 1 and 2 is known.
In the apparatus shown in FIG. 1, rubber rolls 3, 3 rotating in the same direction as the web 1 are arranged in parallel from both sides of the web 1 so as to press them, and both sides of the web 1 passed through a resin reservoir 4 provided thereunder. This is a coating apparatus in which resins 2 and 2 are adhered to a web, and the web 1 is guided between rollers 3 and 3 to squeeze out excess resin liquid to form a coating film. The thickness of the coating film is designed by the pressing force of the rubber rollers 3 and 3. In the case of a rubber roller, however, it is difficult to finish the surface to a mirror surface. The resulting fine streaks tend to form on the surface of the resin film, and when the pressing force is weak, the web 1 is shaken between the rollers, resulting in an inconsistent film thickness.

The apparatus shown in FIG. 2 is a coating apparatus in which cleaning doctors 6 are arranged on both sides of the web 1 instead of the rubber roller 3. However, it is very difficult to finish the doctor's edge with uniform accuracy over the entire length, and it is difficult to secure a uniform coating film on the left and right since thin edges must be installed facing each other. Fine irregularities may be generated due to the shaking of the web 1, and depending on the shape of the tip of the doctor 6, the resin liquid may adhere to the back side of the doctor and damage the coating film, which may cause the formation of streaks. is there.

[0004]

The present invention relates to a double-sided coating method and apparatus for simultaneously forming a resin coating film on both sides of an upwardly running web, in which the pressure of the supplied coating film is made uniform to stably coat both surfaces of the web. It is an object to form a film.

[0005]

Technical Means The first technical means for solving this technical problem relates to a coating method. (A) A coating film having a constant thickness formed on a coating roll through a resin dam. Transferring the film to both sides of the web simultaneously. The second technical means relates to a double-sided coating apparatus. (C) An apparatus for forming a transfer coating film having a constant film thickness on the surface of a coating roll passing through a resin dam with the coating roll inside. (D) Make the outer diameter of the coating roll the same,
(E) there is no gap between the rolls so as not to hinder the running of the web, and (f) the coating rolls are rotated at a constant speed in the opposite direction to the web to simultaneously transfer the coating film on both sides of the web; It is.

[0006] When a coating film having a certain thickness is formed by passing the coating roll through a resin dam, the coating film rotates together with the roll while adhering to the surface of the roll. When the coating film thus formed is supplied from both sides of the running web and transferred at the same time, the transfer pressures on the left and right sides of the web become substantially equal, and a stable coating film can be formed on both surfaces (see claim 1). .

In a double-side coating apparatus, apparatuses for forming a transfer coating film having a constant thickness on the surface of a coating roll passing through a resin dam are arranged side by side with the coating roll inside. The transfer coating film having the determined film thickness is supplied to face each other from both sides. Since the left and right coating rolls have the same outer diameter and are rotated at the same speed in the opposite direction to the web, they are applied to the web of the coating film supplied from the left and right sides of the web running upward between the rolls. Are the same. The gap between the roll surfaces is designed to be a gap that does not hinder the running of the web, so there is no large margin in the running gap of the web, and in that state, a coating film with the same pressure is supplied from the left and right Since the transfer is performed on the web, the load hardly fluctuates during the transfer, and the web does not fluctuate between the rolls. Therefore, a stable coating film can be formed on both sides of the web using the transfer pressure of the coating film supplied (see claim 2).

The interval between the rolls is designed in consideration of the type of the web, the traveling speed, the surface roughness, the type and the viscosity of the resin, etc., and is set to a width obtained by adding 8 to 12 μm to the thickness of the web. By doing so, the above function can be achieved. If it is smaller than 8 μm, the running may be hindered depending on the surface condition of the web, and if it exceeds 12 μm, the web may fluctuate if a slight difference occurs in the balance of the transfer pressure. When forming a transfer coating film having a constant film thickness on the surface of a coating roll passing through a resin dam, a slit coater method using a fixed-type pipe doctor roll (see Japanese Patent Publication No. 54-15571) or A reverse roll coater system using a roll that rotates in the opposite direction to the coating roll is desirable, but a system in which a doctor knife is simply arranged can also be employed. The method of determining the coating film and the gap between the coating rolls depend on the type, viscosity,
The decision is made by comprehensively considering the type of the web, the traveling speed, and the like. As the viscosity of the resin liquid, a resin liquid having a viscosity in the range of 500 to 30,000 cps conventionally used in transfer-type coating can be applied. The resin liquid may be aqueous or solvent-based.

[0009]

According to the present invention, it is possible to form a stable coating film on both sides of the web by equalizing the pressure of the resin liquid to be applied, and thus it is possible to simultaneously form a glossy coating film. Mirror finish coating of 10 to 500 μm (but immediately after coating) is also possible.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a transfer apparatus 10 of a slit coater system using a fixed pipe type doctor roll 16.
1 is a schematic front view of a double-sided coating apparatus using two units. A resin dam 24 is disposed outside the gap between the coating roll 13 forming the transfer film 12 and the doctor roll 16. This dam 24 is provided with a resin supply slit 23 having a width adapted to the width of the coating roll 13,
A supply device (not shown) operates in accordance with the detection signal of the liquid level gauge 21 to supply the resin 2 into the dam 24. It is desirable to adjust the depth of the resin dam 24 according to the size of the gap between the coating roll 13 and the doctor roll 16. In this embodiment, by moving the plate 25 installed on the back to the adjusting screw 26,
The depth of the dam 24 can be adjusted. The opening of the dam 24 is closed by a lid 27 to prevent dust and dirt from entering the dam 24, thereby preventing a change in viscosity of the resin due to evaporation of the solvent.

In this embodiment, the coating film 12 is formed on both surfaces of the thin metal plate 1.
The gap between 3 and 13 is a gap obtained by adding 10 μm to the thickness of the metal plate 1. The coating film 12 whose film thickness is determined by the doctor roll 16 on the coating roll 13 is:
The coating roll 13 once moves downward according to the rotation of the rolls 13 which are rotating in the biting direction.
13 are simultaneously supplied from the left and right directions to the metal plate 1 traveling upward, and once face the gap between the metal plate 1 and the roll 13, and then transfer to the surface of the metal plate 1 to perform transfer. The transferred coating film 12 is directly applied to a metal plate before the drying step. However, a cleaning doctor 14 is provided for the roll 13 so that a part of the coating film is Even if it remains on the surface of the roll 13, it is cut off and collected by the catch pan 15, the surface of the roll 13 is kept in a beautiful state and is exposed to the resin dam 24, so that a beautiful coating film is always formed. .

When coating a web or a net having a large number of holes, it is necessary to close the holes and voids in advance. In this case, the transfer by the transfer device 10 is performed. As a pre-process, filling coating of holes and the like is performed (see claim 3). FIG. 4 is a schematic view of the filling and coating apparatus, in which a doctor contact pressure point 35 is provided on the upper part of the resin dam 34, and the web 31 having the hole 32 is passed through the resin dam 34 to form the hole 32.
, The resin is passed through a doctor contact pressure point 35, and the cleaning resin 36, 36 arranged on the left and right at the time of the passage removes the resin on the surface of the web 31,
The resin is filled only in the holes 32. The web 31 in which the holes 32 are closed in this way is guided to the transfer device 10 as it is, and the coating film 12 is formed on both surfaces.

[Brief description of the drawings]

Fig. 1 Conventional double-side coating device

FIG. 2 shows another conventional double-side coating device

FIG. 3 is a schematic cross-sectional view of a double-side transfer device according to the present invention.

FIG. 4 is a schematic cross-sectional view of a filling coating apparatus used in a pre-process of double-sided transfer.

[Explanation of symbols]

1, web, 2, resin, 10 transfer device, 12 coating film, 13 coating roll, 14 cleaning doctor, 16 pipe type doctor roll, 21 liquid level gauge, 24 resin dam,

Claims (3)

[Claims] 1. A double-sided coating method for simultaneously forming a resin coating film on both sides of a web running upward, wherein a coating film having a constant film thickness formed on a coating roll through a resin dam is coated on both sides of the web. A double-sided coating method that transfers images simultaneously. 2. A double-side coating apparatus for simultaneously forming a resin coating film on both surfaces of an upwardly running web, wherein a transfer coating film having a constant film thickness is formed on the surface of a coating roll passing through a resin dam. The equipment is arranged side by side with the coating roll inside, the outer diameter of the coating roll is the same, there is no gap between the rolls that does not hinder the running of the web, the coating rolls are in the opposite direction to the web, etc. A double-sided coating device that rotates at a high speed and simultaneously transfers the coating film on both sides of the web. 3. The double-side coating method according to claim 1, wherein the web provided with holes or voids is passed through a resin dam, and the resin adhering to the surface is transferred to the scraped web by a cleaning doctor.