JPH07122154B2 - Cleaning method of engraving roll - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention is a cell of an engraving roll used in a gravure roll coating method for coating a synthetic resin liquid or a printing ink on a support such as paper or film. The present invention relates to a method for cleaning by removing solid matters and dirt of synthetic resin and ink clogged in the inside.

(Prior Art) Conventionally, the engraving roll used in the gravure roll coating method is used for the purpose of coming into contact with a liquid such as an adhesive, a synthetic resin liquid, or an ink contained in a coating liquid pan to pick up (pump up) the liquid. Has been done. However, if it is used for a certain period of time, the coating liquid such as synthetic resin or ink will be clogged or soiled as a dried solid substance inside the cells on the surface of the engraving roll, so after using for a certain period of time, The reality is that the cells on the roll surface are always cleaned and reused. Here, the conventional means for removing the clogging and dirt inside the cells of the engraving roll, that is, the conventional method for cleaning the engraving roll will be described. A certain amount of organic solvent that is substantially the same as the solvent is put, and the engraving roll is usually rotated for a certain period of time to dissolve and remove the solid resin of the synthetic resin or ink clogged in the cell. This is also called the re-chrome plating method.The engraving roll is removed from the gravure roll coating device, and the solid resin and dirt of the clogging synthetic resin and ink inside the cell of the roll are chrome plated on the roll surface with acid or alkali. For example, there is a method of exposing the bare metal of the roll body by washing and removing it, and then newly performing chrome plating at a plating factory.

(Problems to be solved by the invention) However, among the above-mentioned conventional techniques, according to the method, there is a drawback in that it is difficult to completely remove the clogging synthetic resin and solids or stains of the ink inside the cell, In addition, according to the method, the work of removing the engraving roll itself is very troublesome first, and the solid resin and dirt of the synthetic resin and ink clogged inside the cell of the removed roll are removed together with the surface chrome plating. However, as a result of having to newly apply chrome plating, the total number of processing steps is large, and therefore, the operation down time of the gravure roll coating line on site is very long, which affects the entire coating line. The impact was immeasurable.

(Means for Solving the Problems) The present invention has been conceived in view of the above problems, and is a state of being set in a coating apparatus without removing an engraving roll from the gravure roll coating apparatus. As it is, it is an object of the present invention to provide a method capable of completely removing the clogged synthetic resin or ink solids and stains inside the cell of the engraving roll very easily and efficiently on site.

The configuration of the present invention will be described below.

That is, the place of the gist of the constitution of the present invention is to put the cellulose acetate coating liquid dissolved in an organic solvent in a coating liquid pan of a gravure roll coating device, rotate an engraving roll, and apply the coating liquid to the roll surface. And the organic solvent in the coating liquid is dried, and then the cellulose acetate coating film layer is peeled off from the roll surface.

Here, the cellulose acetate used is preferably cellulose diacetate or the like, which is dissolved in an organic solvent such as acetone to have a concentration of about 5 to 20%. By the way, when the concentration is 5% or less, the viscosity is too low so that the coating liquid does not adhere well to the roll surface. On the contrary, when the concentration is 20% or more, the viscosity becomes high and sticky workability is not preferable. If the coating liquid drawn up on the roll surface does not dry and is wrapped with a material with good air permeability such as a non-woven fabric to be integrated, the coating layer becomes tougher and peeling easily occurs after that. Therefore, it is preferable.

(Example) Next, one example of the method of the present invention will be described with reference to the accompanying drawings. Cellulose diacetate (produced by Daicel Chemical Industries, Ltd .: cellulose acetate L-70) was applied to a coating liquid pan of a gravure roll coating apparatus. Was used in an acetone solution to adjust the concentration to 10%, and a sufficient amount was added to the surface of the engraving roll when the engraving roll was rotated, and the engraving roll was normally rotated for 1 minute. Then, the coating liquid pan was separated from the engraving roll to prevent the coating liquid from adhering to the roll surface, and the roll was normally rotated for 10 minutes (Fig. 4 is an explanatory view showing the gravure roll coating device in a simplified manner). (1 is an engraving roll, 4 is a coating liquid pan, and 5 is a coating liquid). After that, when the rotation of the engraving roll is stopped, the coating liquid pumped up to the surface of the engraving roll is sufficiently dried and a coating layer is formed on the entire circumference of the roll surface (Fig. 1 is a cross section showing the state. FIG. 3 is an enlarged sectional view of an essential part of FIG. 1 of FIG. 2;
Reference numeral 1 is an engraving roll, 2 is a coating layer, and 3 is a clogged solid material). Then, the surface of the coating layer was cut with a spatula to peel the entire coating layer from the surface of the roll. On the back surface of the peeled coating layer, the solid substance of the synthetic resin, which had been clogged inside the cell of the engraving roll, was completely transferred and adhered (Fig. 3 shows the result of peeling the coating layer of Fig. 2). FIG. 3 is an enlarged cross-sectional view of a part, in which the back surface of the coating layer is formed in a convex shape that matches the concave shape of the cell, and the solid matter 3 completely adheres integrally to the top of the convex portion of the coating layer. It was visually confirmed that the solid matter was completely removed from the cells on the surface of the engraving roll.

(Operation) Therefore, according to the present invention, when the engraving roll is normally rotated in a coating solution pan containing an acetone solution (coating solution) in which cellulose acetate is dissolved, the coating solution is formed on the surface of the roll. Is pumped up to form a thin film of cellulose acetate. Then, a thin film having a constant thickness is formed on the roll surface,
When the engraving roll is kept rotating while the coating liquid pan is separated from the engraving roll, natural drying of the thin film is promoted to form a substantially dried coating layer. Thus, when the coating layer is peeled off by stopping the rotation of the engraving roll, the solid substances of the synthetic resin or the ink clogging the inside of the cell on the roll surface are peeled off in a state of adhering to this, which is called facial treatment. It is completely removed from the inside of the cell on the surface of the roll by adhering and removing dirt on the skin surface of the face with a face pack.

(Effect) The present invention configured as described above has the following effects.

(1) First, according to the method of the present invention, a solid substance of synthetic resin or ink clogged in the cells on the surface of the engraving roll without removing the engraving roll from the gravure roll coating device, while being set in the device. Completely remove dirt and stains,
Since it can be cleaned, there is an advantage that the work is easy and efficient.

(2) In particular, compared with the re-chrome plating method, the processing cost is significantly lower and the processing time is significantly shortened, so the operation down time of the gravure roll coating line is extremely short, which is an economic advantage. Is also big.

(3) Further, in the method of the present invention, if an acetone solution (coating solution) in which cellulose acetate is dissolved is pumped up on the surface of the engraving roll and then a foreskin is wrapped with a material having good air permeability such as a nonwoven fabric before drying. Since the coating film layer is reinforced, the coating film is not fragmented when the coating film layer is peeled off, and peeling can be performed very efficiently.

[Brief description of drawings]

FIG. 1 is a sectional view showing a state in which a coating layer is formed on the engraving roll surface by the method of the present invention, FIG. 2 is an enlarged sectional view of an essential part of FIG. 1, and FIG. 3 is an engraving roll surface of FIG. FIG. 4 is a cross-sectional view of the peeled coating layer, and FIG. 4 is an explanatory view schematically showing a gravure roll coating apparatus to which the method of the present invention is applied. 1 ... engraving roll, 2 ... coating layer, 3 ... clogged solid matter, 4 ... coating liquid pan, 5 ... coating liquid.

Claims (2)

[Claims] 1. A cellulose acetate coating solution dissolved in an organic solvent is placed in a coating solution pan of a gravure roll coating apparatus, an engraving roll is rotated, and the coating solution is pumped up to the surface of the roll, A method for cleaning, comprising drying the organic solvent and then peeling off the cellulose acetate coating layer from the surface of the roll. 2. After pumping the coating liquid onto the roll surface, a non-woven fabric is applied to the roll surface before drying, the organic solvent in the coating liquid is dried, and cellulose acetate is impregnated from the roll surface. The cleaning method according to claim 1, wherein the dried nonwoven fabric is peeled off.