JPS6223626B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a technical improvement in the nozzle circulation system of a two-roll reverse roll coater, and its purpose is to provide a low viscosity coating (1 to 1000 CPS) on the continuously running substrate surface. ) In addition to uniformly and thinly coating a fixed amount of solution resin, by integrating the liquid supply nozzle device, doctor knife, and liquid collection van, the liquid flow area is sealed and the solution is A coating method that reduces evaporative viscosity changes as much as possible and recirculates overcharged solution to eliminate liquid loss and alleviate the solvent atmosphere around the coating area. It is not intended to be provided.

According to the conventional nozzle coating method using a two-reverse roll mechanism, when the backing roll 15 and the doctor roll 16 are arranged horizontally (see FIG. 3), the backing roll 15 is supplied from the nozzle 17 provided on the lower surface of the backing roll 15. When the overcharged solution reaches the contact point between the bucking roll 15 and the doctor roll 16, the overcharged solution is transferred to the doctor roll 1.
6 and scraped off by the doctor knife 18, the liquid also flows back onto the backing roll 15 and doctor roll 16 surfaces, or the liquid returns to the solution supply part of the nozzle 17 in the form of a streak. Occur.
As a result, the solution is not supplied uniformly from the nozzle to the contact point between the bucking roll 15 and the doctor roll 16, and streaks appear on the coated surface in the web traveling direction, making it impossible to obtain a uniform coated surface. There are drawbacks that are difficult to overcome.

In addition, the space between the solution flow and recovery van 19 is open, and the area around the coating area is filled with solvent.
At the same time as the atmosphere deteriorates, the solution once supplied comes into contact with the outside air, causing evaporation and changes in viscosity, which poses a problem in terms of recycling and reuse of the recovered solution.

Therefore, the present invention has been made to eliminate the inconveniences and shortcomings of the conventional technology.Moreover, the bucking roll and doctor roll are placed in vertical positions, and a coating method using a closed nozzle system is adopted. This coating method does not have the drawbacks of other coating methods.

The gist of the present invention is as follows.

In a coating method in which a very thin solution of low viscosity is applied to the surface of a substrate of relatively uniform thickness such as film or paper that runs continuously, the back-up roll that supports the substrate and the coating thickness are used. A doctor roll that rotates in the opposite direction to the direction of movement of the substrate is arranged vertically so as to regulate By installing a hopper mechanism with an integrated cutting knife nearby,
The solution pumped by the pump is uniformly applied to the substrate in the width direction from the solution supply nozzle, and the coating thickness is regulated by a doctor roll, and the excess liquid is collected from the cutting knife into the cathippan in the hopper mechanism and circulated. 2. It has a closed type low viscosity solution circulation hopper, which is completely sealed from supply to return for coating the substrate.
This is a nozzle coating method using this reverse roll mechanism.

Next, an embodiment of the present invention will be described based on the example of the implementation mechanism shown in FIGS. 1 and 2.

A back up roll 1 supporting the base material 14 and a doctor roll 2 disposed vertically downwardly support the base material 1.
It rotates in the opposite direction to the direction of movement in step 4.

Further, this doctor roll 2 has a built-in speed change mechanism that can change the running speed of the substrate from 1/1 to 1/4 so that a mirror-like state of the coated surface can be obtained in accordance with the properties of the solution.

The supply nozzle 3 has its tip directed on the back-up roll 1 and in front of the doctor roll 2, and applies the solution uniformly in the width direction using pump pressure. At this time, the gap between the base material 14 and the supply nozzle 3 is set in advance to about 60 to 100 μm, and the gap can be adjusted evenly by the screw 4 in left and right forward and backward movements.

Therefore, the solution overflowing from the supply nozzle 3 flows to both ends by the tow 5 provided on the back side thereof and falls into the catch pan 6. Then, the solution applied to the substrate 14 from the supply nozzle 3 obtains the final target coating film thickness in the gap 7 of about 30 to 60 μm formed by the backup roll 1 and the doctor roll 2.

The solution that cannot pass through the gap 7 is pulled back in the rotational direction of the doctor roll 2, collected by the cut knife 9 that is constantly being processed by the air cylinder 8 from the doctor roll 2 into the separation cathunter 6, and sent through piping to the supplier. Return to tank (not shown).

In other words, the solution is firstly regulated by the supply nozzle 3 and then secondarily regulated by the doctor roll 2, so that it flows downward in one direction, and once discharged, the solution may flow backward or stagnate in some parts. without doing,
This eliminates the occurrence of vertical streaks on the painted surface and horizontal streaks due to the knotting phenomenon of solution scum.

The cut knife 9 and the catch pan 6 are integrally manufactured, have a side seal plate 10, and have a side seal plate 10, and a supply nozzle 3
It is an integrated hopper mechanism including.

As a result of the above, the solution supplied from the supply nozzle 3 does not come into contact with the outside air until it is collected in the catch pan 6, thereby preventing the solution from evaporating.
Since viscosity changes can be prevented, the coating film thickness can be stabilized over time.
The scattering of the solution in the above) is also prevented, and the solvent atmosphere around the coating area can also be improved.

Therefore, when the coating operation by the implementation mechanism of the present invention is stopped, the supply nozzle 3 is separated from the back-up roll 1 around the arm fulcrum shaft 11 that supports it, and the protrusion 12 below the supply nozzle 3 is moved away from the back-up roll 1. teeth,
It comes into contact with the roller 13 at the rear of the catty pan 6,
The pressurized state of the cutting knife 9 is simultaneously released by the doctor roll 8. This movement mechanism protects the life of the edge and is a safety mechanism that operates only when necessary. In this way, when the supply nozzle 3 is opened, the cutting knife 9 is also opened with a slight delay, and when viewed from above, the cutting knife 9 is just opened.
The hopper-like mechanism is designed to be shaped like a bowl with the bottom being easy to clean.

As described above, the present invention is a coating method that uniformly and thinly coats a constant amount of a low-viscosity resin solution onto a continuously running substrate surface, which reduces evaporation of the solution and changes in viscosity, and reduces overcharging. This method is of great industrial value as a coating method that improves the efficiency of this type of coating by recycling the di-solution.

[Brief explanation of the drawing]

1 and 2 are side explanatory views showing an example of an implementation mechanism according to the present invention, and FIG. 3 is a side view explanatory view of a conventional method.

Claims (1)

[Claims] 1 In a coating method in which a very thin solution of low viscosity is applied to the surface of a continuously running base material of relatively uniform thickness such as film or paper, the back-up roll that supports the base material and the coating In order to regulate the thickness, a doctor roll that rotates in the opposite direction to the direction of movement of the substrate is arranged vertically, and a solution supply nozzle is installed near the contact point between the back-up roll and the doctor roll to scrape off excess liquid. By installing a hopper mechanism with an integrated cutting knife nearby, the solution fed by the pump is uniformly applied to the substrate in the width direction from the solution supply nozzle, and the coating thickness is regulated by the doctor roll. The surplus liquid is collected and circulated from the cutting knife to the catch pan in the hopper mechanism, and has a closed type low viscosity solution circulation hopper, which is completely sealed from supply to return to perform coating on the substrate. Nozzle coating method using two reverse roll mechanisms.