JPH0759310B2 - Coating method and device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to photographic light-sensitive materials such as photographic film and photographic paper, photoengraving materials, magnetic recording materials such as magnetic recording tape, pressure-sensitive recording paper, and heat-sensitive recording paper. For improving the process of applying a liquid coating composition to a continuously running long flexible support (hereinafter referred to as "web") in the production of a recording material, and more particularly to an improved bead coating method and apparatus. Is.

[Conventional technology]

Conventionally, various methods have been proposed as a method for applying a coating liquid to a web that is continuously running.

Generally, the coating process is divided into a part for transferring the coating liquid to the web (hereinafter referred to as “application system”) and a part for measuring the coating liquid transferred to the web to a desired coating amount (hereinafter referred to as “measuring system”). Therefore, the coating methods were classified according to the difference between the application system and the measurement system.

A roller coating method, a dip coating method, a fountain coating method, etc. have been known on the basis of the difference in the application system, and an air knife coating method, a blade coating method, a bar coating method etc. have been known on the basis of the difference in the measuring system.

Of these, the extrusion coating method and the bead coating method have been used as precise coating methods that do not directly contact the support. The coating method using an extrusion type coater such as the extrusion coating method and the bead coating method is described in, for example, JP-B-45-12390 and JP-B-46.
-26236 and Japanese Patent Publication No. 47-24650, an extrusion multi-layer coating apparatus, JP-A-50-
A coating method for a single layer disclosed in Japanese Patent No. 142643,
Alternatively, many patents have been filed such as the coating method and apparatus disclosed in JP-A-56-95363 and JP-A-62-110776, in which the discharge slot is located upward.

[Problems to be Solved by the Invention]

However, when the coating liquid is applied to a web of an arbitrary width within the width of the liquid discharge port of a constant slot, the roller is generally covered by the coating liquid discharged from the slot of the coater protruding outside the width of the web, and The edges of the web are dirty. As a method for preventing this stain, JP-A-56-9536
It is possible to apply the method disclosed in JP-A No. 3 and JP-A-62-110776 without soiling the roller under extremely limited conditions, but the roller becomes soiled due to speedup or an increase in the amount of liquid sent. Come on.

The present invention prevents such roller dirt or web edge dirt from occurring even when the slot width is larger than the web, thereby changing the discharge port width of the coater even when the web width changes. It is intended to provide a coating method and a device capable of coating without coating.

[Means and Actions for Solving the Problems]

The above-mentioned objects of the present invention are: (1) In a method of forming a coating solution bridge between a slot and a support wound around a backup roller and running to apply the coating solution to the support, When the slot width becomes large, the coating liquid is applied by applying a gas from a lateral direction with a slit nozzle against the rise of the coating liquid discharged from the liquid discharge port of the slot that extends outside the support width. A coating method, wherein coating is performed without forming a coating liquid bridge between the liquid and the roller, and without applying the coating liquid to the roller and the edge of the support.

(2) In a coating device that supplies a coating liquid from a slot to the surface of a continuously running support, when the slot width is larger than the support width, the liquid discharge port of the slot protruding outside the support width. A coating apparatus having a slit nozzle that applies a gas in a slit shape to the rising of the discharged coating liquid, and the apparatus having the slit nozzle that moves in accordance with the width variation of the support body. .

Achieved by

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is a perspective view (a) and a side sectional view (b) of one embodiment of a coating apparatus for explaining the coating method of the present invention.

In FIG. 1, the extrusion type coater 4 performs coating by forming a coating liquid bridge between the web 1 and the coater lip surface 8 of the coater slot on the lower surface of the web 1. Also, slit nozzle (hereinafter referred to as nozzle)
The reference numeral 5 applies the gas ejected from the nozzle 5 between the hack-up roller 3 and the coater lip surface 8 protruding outside the web edge 7.

The gas ejected from the nozzle 5 is the coater lip surface 8
It is preferable to inject at a wind speed of 0.05 to 15 m / sec, more preferably 0.5 to 5 m / sec.

If the wind speed is too high, the coating liquid rising on the coater lip surface 8 will be blown off to form a mist, and the backup roller 3 and the like will be contaminated with the coating liquid.

On the other hand, if it is too low, the rise of the coating liquid on the coater lip surface 8 cannot be reduced as a matter of course.

The tip of the nozzle 5 is against the coater lip surface 8,
It is desirable to install it from several mm to several cm.

The shape of the nozzle 5 is not particularly limited, but if possible,
A flat shape that does not diffuse wind is desirable.

Further, the nozzles 5 may be jetted from the coated surface of the web as shown in FIG. 1 (b) or may be jetted from the non-coated surface of the web as shown in FIG.

When the width of the web 1 moves to the left and right, the nozzle 5 detects the position of the edge 7 of the web by the edge position detector 9 as shown in FIG. 3 and corresponds to the lateral movement of the edge 7 of the web. Then follow the guide rails 12 and screwdriver 11
It is preferable to provide a device for moving the edge position detector 9 and the nozzle 5 integrally with each other by moving, and automatically moving the nozzle 5 in the width direction corresponding to the position of the web edge 7.

When the description is further added to the present invention, the coating liquid in the present invention is not particularly limited, and includes water or an organic solvent liquid of a polymer compound, a pigment aqueous dispersion liquid, a colloidal solution and the like. The physical properties of the coating liquid are not particularly limited, but the lower viscosity is suitable as the condition of the liquid coated on the web, and the condition of 100 cps or less, particularly 50 cps or less is suitable. The surface tension is not particularly limited, but 50dy
Good results are obtained at ne / cm or less.

The web in the present invention means paper, plastic film,
Includes resin coated paper, aluminum web, synthetic paper and the like. The material of the plastic film is, for example, polyolefin such as polyethylene or polypropylene, polyvinyl acetate, polyvinyl chloride; vinyl polymer such as polystyrene, polyamide such as 6,6-nylon or 6-nylon, polyethylene terephthalate, polyethylene-
Polyester such as 2,6-naphthalate, polycarbonate, cellulose triacetate, cellulose acetate such as cellulose diacetate and the like are used. Polyolefin such as polyethylene is typical as the resin used for the resin coated paper, but the resin is not necessarily limited to this.

〔Example〕

In order to further clarify the effects of the present invention, examples will be given.

Example 1 A coating liquid having a composition and physical properties shown in Table 1 was applied to the surface of a polyethylene terephthalate film having a thickness of 200 μm and a width of 1000 mm by using a coating apparatus shown in FIG. 1 and a coating speed of 60 m / min.
The coating amount was 80 cc / m ² . At this time, air was ejected from the slit nozzle 5 on the coater lip surface 8 at a wind speed of 2 m / sec.

At this time, the coating liquid could be applied to the backup roller 3 without any transfer.

Table 1 Acrylic acid copolymer: 6 parts by weight Butyl glycol: 58 〃 Acetone: 36 〃 Dye: 0.1 〃 Viscosity: 11 cps Surface tension: 29 dyne / cm Comparative example-1 Coating solution shown in Example-1 Under the same conditions, except that the air from the nozzle was stopped and coating was performed, the coating liquid adhered and transferred to the backup roller 3 as shown by 13 in FIG.

〔The invention's effect〕

As described above, according to the coating method and apparatus of the present invention, even when the coater slot width is larger than the web width, it is possible to coat without applying the coating liquid to the web edge and the roller.

[Brief description of drawings]

FIG. 1 is a perspective view (a) and a side view (b) of one embodiment of a coating apparatus for explaining the coating method of the present invention, and FIG.
A side view of another embodiment of the coating device for explaining the coating method of the present invention as in FIG. 6B, and FIG. 3 has a device for controlling the position of the slit nozzle of the present invention corresponding to the web edge. FIG. 4 is a perspective view of one embodiment of the coating apparatus, FIG.
In the figure, it is a perspective view showing a coating state when a nozzle is not used. 1 ... Web 2 ... Coated web 3 ... Backup roller 4 ... Extrusion type coater 5 ... Slit nozzle (nozzle) 6 ... Gas pipe, 7 ... Web edge 8 ... Coater lip surface 9 ... Edge position detector 10 ...... Connection arm 11 ...... Driver 12 …… Guide rail 13 …… Application liquid adhered and transferred to the web edge and backup roller

Claims (2)

[Claims] 1. In a method of forming a coating solution bridge between a slot and a support wound around a backup roller and applying the coating solution to the support, the slot width is larger than the support width. In this case, the gap between the coating liquid and the roller can be increased by applying a gas from the lateral direction with a slit nozzle to the swell of the coating liquid discharged from the liquid discharge port of the slot that extends outside the support width. The coating method is characterized in that the coating liquid is applied to the roller and the edge of the support without applying the coating liquid. 2. A coating device for supplying a coating liquid from a slot to the surface of a continuously running support, and when the slot width is larger than the support width, the liquid in the slot protruding outside the support width. A slit nozzle that applies gas in a slot shape to the rise of the coating liquid discharged from the discharge port, and the slit nozzle is provided with a device that moves in accordance with the width variation of the support. Coating device.