JPH0283060A - Backing roll purification device - Google Patents

Abstract

PURPOSE:To apply a coat stably by installing a spray gun with a nozzle for atomizing purification water on both edges of a backing roll at the top of a shower. CONSTITUTION:Web 5 before being coated enters a coating device from behind an applicator roll 2 in such a manner that the web comes in contact with a backing roll 1. A coating liquid is transferred to the applicator roll 2 from a color pan 3, and then is transferred to the web 5 by means of a nip between the applicator roll 2 and the backing roll 1. Next, the coating liquid is scraped off by a blade 4 until a required amount of coating liquid is left. The coating liquid remaining on the backing roll 1 is diluted by purification water from a spray gun 8, then the entire width of the backing roll is showered with purification water 7 to dilute the coating liquid on it. After this, the diluted coating liquid and other dirt are scraped off by a purification doctor 6. Thus the contamination can be reduced significantly.

Description

DETAILED DESCRIPTION OF THE INVENTION [A] Field of Industrial Application The present invention relates to an apparatus for cleaning a backing roll of an apparatus for applying a coating liquid to wear such as paper or plastic film.

[8] Conventional technology In general, coating equipment for producing coated paper transfers more than the required amount of coating liquid, and then scrapes off the excess coating liquid using a metering device such as a blade. be done. At this time, the coating liquid is transferred to a width greater than the width of the paper, and the coating liquid transferred to the paper and the coating liquid transferred to the backing roll are also scraped off, but it is difficult to completely scrape off, and unless this is washed, Problems occur such as drying, staining the coated paper, and making metaling difficult due to the dried coating liquid. For this reason, the coating equipment is equipped with a backing roll cleaning device. This backing roll cleaning device has a structure in which cleaning shower water is flowed inside a cleaning doctor set diagonally so that the tip is pressed against the backing roll to rinse away the coating liquid.

The causes of stains on the surface of the backing roll in the above-mentioned coating device are as follows.

(b) If the ware is porous such as paper, dirt penetrates through the ware and reaches the backing roll during coating; (b) dirt is caused by foreign matter on the web surface; (c) with double-sided coating, the coated surface is backing. There is some peeling of the coating layer during the pre-coating process when it comes into contact with the roll, and (2) some coating liquid adhering to the edges on both sides where there is no web.

As a method for cleaning such stains on the backing roll, the stains in (a), (b), and (c) above can be sufficiently cleaned using a conventional backing roll cleaning doctor and cleaning shower, and are relatively easy to clean. Low coating liquid concentration, coating speed,
If a coating liquid with higher stability can be used in view of the required coated paper quality, the stain (d) can also be cleaned without any particular problem.

[C] Problems to be Solved by the Invention However, due to the recent increase in the speed of coating machines, the demand for higher operating efficiency, and the decline in the stability of coating fluids due to the demand for higher quality, (d) The problem of dirt has come into close focus.

The stains on the edges of the backing roll caused by the coating liquid on both sides without webs are mixed and diluted by supplying a large amount of cleaning shower water and scraped off by a cleaning doctor, but the backing roll cleaning The adhesive scum generated in the device is removed by diluting the coating liquid transferred onto the backing roll (1) at the contact point between the tip of the cleaning doctor (6) and the backing roll (1) with the cleaning shower water. In the process of being subjected to large shearing forces,
This dirt, which is caused by adhesives, especially polymer latex, coagulating and forming a film, accumulates on the cleaning doctor and lifts the cleaning doctor, creating a gap between the cleaning doctor and the backing roll, causing the doctor to wash the shower water. This can lead to accidents involving water. If water leakage occurs, the web before coating will be soiled or broken, making it impossible to continue coating any longer.If water leakage occurs to some extent around the edge of the cleaning doctor, the cleaning doctor must be replaced, reducing work efficiency. It will drop.

As a result of intensive studies, the present invention was developed with the aim of suppressing as much as possible the occurrence of stains on the cleaning doctor, which causes water around the backing roll.The present invention was developed by selectively diluting the stains on the edge of the backing roll before the cleaning doctor. However, the present invention has been achieved in which the cleaning load on a part of the cleaning doctor is reduced.

rD] Means to solve the problem Conventional cleaning doctor The cause of stains on the edge part is the backing roll, the high concentration coating liquid transferred to the edge part is diluted to a certain concentration with cleaning water, and the dilution is The problem is that the degree of oxidation is not sufficient to maintain the stability of the coating fluid. If the diluted coating liquid enters the cleaning doctor in this state, it loses stability when it is scraped off by the doctor, resulting in coagulation of latex and staining.

Experiments to date have shown that if the highly concentrated coating liquid on the backing roll edge is diluted in advance to a level that does not cause problems, stains on the cleaning doctor edge are less likely to occur. A spray gun was installed in the area where the coating liquid had been transferred, and the transferred coating liquid was diluted.

That is, the present invention provides a coating device that includes a metering section, an applicate section, and a backing roll section. This is a backing roll cleaning device in which a shower is installed and spray guns are installed on both sides of the backing roll above the cleaning shower, and the coating liquid transferred to the backing roll edge portion is selectively applied using the backing roll cleaning device. This is a backing roll cleaning device that reduces the load on the subsequent cleaning doctor.

[63 Effect] Before the existing cleaning doctor, a spray gun that selectively dilutes and cleans highly concentrated coating liquid is installed at the edge of the backing roll for dilution and cleaning, reducing the cleaning load on the cleaning doctor and removing dirt. Occurrence can be prevented.

[F] Example Embodiments of the present invention will be described based on the drawings.

Embodiment 1 FIG. 1 is a schematic side view of a backing roll cleaning device showing one embodiment of the present invention, and FIG. 2 is a schematic front view of FIG. 1.

In the figure, 1 represents a backing roll, 2 an applicator roll, and 3 a coating liquid satsuma color pan for supplying a coating liquid to the applicator roll 2, which is provided below the backing roll 1. 4 is a blade for scraping off the excess coating liquid applied to the surface of the wear 5 to a required amount. Reference numeral 6 is a cleaning doctor for scraping off dirt substances adhering to one surface of the backing roll, 7 is a washing shower for cleaning the cleaning doctor, and 8 is a cleaning doctor for cleaning the edges of both sides of the backing roll 1, which is a feature of the present invention. A spray gun 8 is used for dilution cleaning, and 9 represents a pipe for sending cleaning water to the spray gun.

We investigated both two-fluid nozzles and one-fluid nozzles for the nozzle shape of the spray gun, but the two-fluid nozzle is effective when the amount of coating liquid transferred onto the backing roll is small, and there are many seedlings of coating liquid. At the time, a one-fluid nozzle was effective.

This is because the dilution effect of water differs depending on the carrier of the coating liquid, and in a coating machine, the amount of coating liquid transferred onto the backing roll 1 is generally small, so a two-fluid nozzle is effective.

Also, regarding the spray shape of the nozzle, the backing roll 1
It is important that the same amount of water be applied across the width of the upper coating liquid transfer area, and the effective spray shape is not particularly limited.

The shielding plate 10 to prevent the dilution water from scattering becomes necessary as the flow rate of the dilution water increases, but if the conditions are met that the splashed water of the dilution water does not hit the web 5 and does not enter the coating liquid recovery system, Its installation position and shape are not particularly limited.

Next, to explain the cleaning method of the backing roll cleaning device of the present invention, the web 5 before coating is removed from the applicator roll 2.
It enters the coating device from the rear in contact with the backing roll 1. Application liquid is applicator roll 2 from color pan 3
Applicator roll 2 and backing roll 1
It is transferred to the web 5 by the nip, and scraped off by the blade 4 to the required coating distance. The coating liquid transferred to the coating liquid transfer portion a of the backing roll on the outside of the web end 5' is transferred to the blade 4.
However, the coating liquid left on the backing roll 1 is diluted with cleaning water from the spray gun 8, and then the backing roll width is further diluted with cleaning shower water 7, and the cleaning doctor 6 removes the diluted coating. The liquid and other dirt are scraped off, washed away by a cleaning water shower 7 at the nip between the cleaning doctor 6 and the backing roll 1, and discharged to both sides of the cleaning doctor 6. Here, the width of the cleaning doctor 6 is slightly larger than the width of the backing roll 1, and the cleaning water is discharged through a cleaning water discharge gutter provided at the lateral end of the doctor.

Example 2 Using a two-fluid spray gun in the backing roll cleaning device of Example 1, a coating liquid with the following formulation was applied to one side of the 52 g/rrt wear at a speed of 900 m/min at a speed of 900 m/min. was applied for about 8 hours, but no stains were observed on the cleaned doctor edge.

Note that the water flow rate of the spray gun varies depending on the base of the coating liquid being transferred to the backing roll, but in general, the higher the flow rate, the better. The coating liquid on the backing roll is 8%
It was confirmed that there would be no problem at all if the flow rate was such that the solid content concentration was as follows.

Coating liquid〉 Kaolin clay 50 weight ω part heavy charcoal 50 weight hanging part and polyacrylic I
Disperse and diffuse O.
To the slurry adjusted to 2% by weight, 10 parts by weight of styrene-butadiene latex and 5 parts by weight of phosphated starch were added to make the solid content concentration 64% by weight.

Comparative Example 1 Coating was performed under the same conditions as in Example 2 except that a conventional cleaning device was used, except that the spray gun was removed. As a result, stains were generated on the cleaning doctor edge after about 1 hour. I started.

[G] Effects of the invention As is clear from the examples, by installing a spray gun in front of the conventional cleaning doctor edge, it is possible to significantly reduce the stains generated on the conventional cleaning doctor edge. Ta.

[Brief explanation of the drawing]

FIG. 1 is a schematic side view of a packing roll cleaning device showing one embodiment of the present invention. FIG. 2 is a schematic front view of FIG. 1. 1...Backing roll 2...Applicator roll 3...Color pan 4...Doctor 5...
Wear 5'... Web end 6... Cleaning doctor 7... Cleaning shower 8... Spray gun 9... Pipe 10... Shielding plate a... Backing roll coating liquid transfer portion 12χ

Claims (1)

[Claims] (1) In the backing roll cleaning device of a coating device equipped with a cleaning shower and a cleaning doctor over the entire surface width of the backing roll with a metering device, cleaning water is sprayed onto both edges of the backing roll above the shower. A backing roll cleaning device equipped with a spray gun that has a nozzle.