JP2925090B2 - Coating device and coating method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION a. Industrial Field of the Invention The present invention relates to the production of photographic film, photographic paper, magnetic tape, adhesive tape, pressure-sensitive recording paper, photosensitive printing plate, etc. The present invention relates to a coating apparatus and a coating method for uniformly applying various coating liquids to a running belt-like support (hereinafter, referred to as a web).

b. Conventional technology As a method of applying a coating solution to a continuously running web, various methods have been conventionally proposed, for example, a roller coating method, a blade coating method, a bead coating method, a curtain coating method, an air coating method. A knife coating method, an extrusion (extrusion) coating method, a bar coating method, and the like are known.

c. Problems to be Solved by the Invention Among the above coating methods, the roller coating method, the blade coating method and the bead coating method, when coating the coating liquid,
A rubber roller or a metal roller is used as a medium, and the uniformity of the obtained coating film depends on the quality of the surface of the roller, for example, whether or not the surface is smoothly finished. Therefore, in order to obtain a uniform coating film, it is necessary to use a roller having a good surface, and there is a defect that polishing unevenness on the roller surface appears on the surface of the coating film.

Also, the curtain coating method has a drawback that it is difficult to obtain a thin coating film, and the air knife coating method has a disadvantage.
There is a disadvantage that air wind unevenness appears on the coating surface of the coating film.

Further, in the extrusion coating method, the thickness of the coating film obtained varies depending on the running speed of the web and the amount of the discharged coating liquid. For this reason, in order to obtain a coating film having a uniform film thickness over the entire surface, the coating device needs to have considerable accuracy, and enormous cost is required to produce a high-precision device. There are drawbacks such as.

The bar coating method is a simple method, and as shown in FIG. 2, a coating film 4 formed by transferring a coating liquid 2 to a web 3 with a roller 1 is scraped off with a bar 5. There is a disadvantage that the coating unevenness generated on the roller 1 cannot be completely eliminated by the bar 5.

In order to solve this drawback, Japanese Patent Publication No.
As shown in the figure, a method has been proposed in which the liquid is applied while forming a liquid pool 7 by applying pressure as indicated by an arrow B immediately before a contact portion 6 between the bar 5 and the web 3. However, when the web 3 is run at a high speed, the problem that the coating liquid 2 embraces bubbles and the coating film 4 has uneven vertical stripes has not yet been solved.

In FIGS. 2 and 3, reference numeral 8 denotes a drying device.

The present invention has been made in order to solve the above-mentioned drawbacks in the conventional coating method. In short, the coating apparatus and the coating method in which the extrusion coating method and the bar coating method are combined provide uniform coating without coating unevenness. An object of the present invention is to provide a coating method which can obtain a thickness and can perform uniform coating from low-speed running to high-speed running.

d. Means for Solving the Problems The present invention provides an extrusion mechanism for applying a coating liquid to a web by causing a coating liquid supplied by a supply unit to be discharged from a slit, and an application mechanism configured to apply the coating liquid to the web by the extrusion mechanism. A coating mechanism having a scraping mechanism for scraping the applied coating solution to a desired film thickness by a bar, wherein the interval between the slit and the scraping position of the bar is such that the coating solution is discharged from the slit. The coating device is characterized in that the coating liquid is supplied at intervals not causing turbulence immediately before the bar and generating no flow unevenness, and the continuously running web, through the slit. The above-described application is performed at a position where the application liquid discharged from the slit does not cause turbulence immediately before the bar and does not cause unevenness in the flow. An object of the present invention is to provide a coating method characterized by scraping a liquid with a bar to obtain a desired film thickness.

 FIG. 1 is a schematic view of a coating apparatus 11 of the present invention.

The coating device 11 shown in FIG. 1 includes an extrusion mechanism 12 and a scraping mechanism 13.

The extrusion mechanism section 12 includes a liquid feed pump 15, a coating liquid supply pipe 16, a liquid storage section 17 formed in the middle of the supply pipe 16,
And a slit 18 provided at the application liquid discharge site.

In addition, the scraping mechanism 13 includes the extrusion mechanism 12
A bar 21 for scraping the coating liquid 20 applied to the web 19 to a desired coating amount, a liquid reservoir 22 for collecting and storing the scraped coating liquid 20, and a motor for rotating the bar 21 (Not shown).

In the coating device 11, the interval between the slit 18 and the scraping position of the bar 21 (the interval indicated by L in the figure) is such that the coating liquid 20 discharged from the slit 18 does not cause turbulence immediately before the bar 21, In addition, the distance does not cause unevenness of the flow. In particular
The interval is 10 to 200 mm. When the interval is 10 mm or less, the coating liquid 20 discharged at a high pressure causes a turbulent flow immediately before the bar 21 and coating unevenness is likely to occur. On the other hand, when the thickness is 200 mm or more, unevenness of the flow of the coating liquid tends to occur on the coating surface of the web 19 during high-speed running, and a thick portion and a thin portion occur, which causes uneven coating.

In the coating device 11, the slit 18 preferably has a slit width of about 100 μm to 400 μm. If the thickness is less than 100 μm, the applied amount is not accurate, and if the thickness is more than 400 μm, a large amount of the coating solution is sent and the amount of the coating solution becomes uneven.

Further, the interval between the web 19 and the slit 18 in the coating device 11 is so small that it does not touch. If this interval is too wide, it is necessary to discharge a large amount of the coating liquid, and when the web 19 and the slit 18 come into contact with each other, the coating surface of the web 19 is scratched.

As the bar 21, a wire having a certain diameter is tightly wound around the surface of a rod (hereinafter referred to as a wire bar), or a groove having a certain width and a certain depth is formed on the surface of the rod itself at a certain pitch. (Hereinafter, referred to as a grooving bar) or a rod obtained by etching a certain mold on the rod itself. Among these, a wire bar is preferable in terms of accuracy.

When a wire bar is used, a suitable overall diameter (diameter indicated by l in the figure) is 5 mm to 30 mm, preferably 6 mm to 20 mm. When the bar is not more than 5 mm, when the bar is rotated, the core is liable to be blurred, and coating unevenness is likely to occur at right angles to the web 19. In the case of 30 mm or more, vertical unevenness is likely to occur as the traveling speed of the web 19 increases.

Wire diameter is 0.08-1.2mm, preferably 0.10-1.0
mm is appropriate. When the thickness is 0.1 mm or less, a high-concentration coating solution 20 must be prepared, which makes it difficult to dissolve the solute. In the case of 1.0 mm or more, conversely, a dilute solution is required,
In the drying stage, application unevenness is likely to occur due to wind, which is not preferable.

As the material of the wire, iron, stainless steel, chrome-plated one thereon, or plastic fiber such as nylon can be used.

The coating apparatus 11 has an extrusion mechanism 12 and a scraping mechanism 13 incorporated in the same apparatus. For this reason, a leveling surface 25 for leveling the coating liquid 20 can be formed between the slit 18 and the bar 21. When the leveling surface 25 is formed, the coating liquid 20 is leveled on the leveling surface 25, spreads uniformly, and can be applied to the application surface of the web 19 without unevenness.

The coating method of the present invention can be applied to, for example,
Is carried out as follows.

That is, the web 19 is continuously run in the direction indicated by the arrow A in FIG. 1, the coating liquid 20 is fed to the coating liquid supply pipe 16 by the liquid feed pump 15, and is supplied to the web 19 from the slit 18 as a uniform liquid flow. Thus, a predetermined amount or more of the coating liquid 20 is applied to the web 19, and the coating liquid 20 is scraped off at a scraping position 23 of the bar 21 from the web 19 running while the coating liquid 20 is not dried. Booth for drying and weighing
Conveyed to 24, where it is dried and wound up at a web take-up section (not shown) or continuously cut to a desired size.

The application liquid 20 is temporarily stored in the liquid storage part 17 by the liquid feed pump 15, is pushed up by the liquid pressure, overflows from the slit 18, and is applied to the web 19.

In the above-described coating apparatus 11, the interval between the slit 18 and the scraping position 23 of the bar 21 (the interval shown by L in the figure) is set to 10 mm to 20 mm.
It is set to 0mm. For this reason, the coating liquid 20 does not cause turbulence immediately before the bar 21, and even when the web 19 runs at high speed, no coating unevenness occurs on the coating surface of the web 19. Therefore, by drying in the drying booth 24, a coating film having a uniform film thickness can be obtained.

The excess coating liquid 20 scraped off by the bar 21 is all recovered in the liquid reservoir 22, and after recovery, pumped again by the pump 15 for use.

When using the coating device 11, the bar 21 can be used stationary, or can be driven and driven to rotate forward at the same peripheral speed as the web 19, or can be used while rotating faster than the speed of the web 19. . Conversely, it can be used by rotating it slowly. Further, it can be used after being rotated in reverse (reverse).

The above-described coating method is performed using the coating apparatus 11 in which the extrusion mechanism and the scraping mechanism are incorporated in the same apparatus. However, the extrusion mechanism and the scraping mechanism are not necessarily included in the same apparatus. It does not need to be embedded.

The coating liquid used in the present invention is not particularly limited, and an aqueous coating liquid, an organic solvent coating liquid, an emulsion coating liquid and the like can be used, and a photosensitive liquid for a photosensitive printing plate is particularly suitable. I have. For example, a negative photosensitive solution in which a mixture of a diazo resin and acrylates is dissolved in an organic solvent, a positive photosensitive solution in which an O-quinonediazide compound and a novolak phenol or cresol resin are dissolved in an organic solvent, Is a photosensitive solution using a photocrosslinkable photopolymer such as phenylenediacrylic acid, a photosensitive solution of a photopolymerizable photopolymer composition comprising an addition-polymerizable ethylene compound and an alkali-soluble resin, an azide photosensitive material and a novolak phenol resin. And other photosensitive liquids can be used. In addition, a photosensitive liquid for electrophotography using a zinc oxide-based material or an organic photoconductor as a photosensitive material can be used.

Organic media for dissolving these photosensitive liquids include acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, methanol, ethanol, propanol, isoamyl alcohol, diacetone alcohol,
Methyl acetate, ethyl acetate, butyl acetate, methyl cellosolve, ethyl cellosolve, butyl cellosolve, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether, propylene glycol monoethyl ether acetate, dipropylene glycol monomethyl ether, tripropylene glycol Monomethyl ether, benzene, toluene, xylene, dioxane, methylene chloride, ethylene chloride, chlorofluorocarbon, tetrahydrofuran, dimethylformamide, dimethylsulfoxide and the like are used, and at least one of them is used.

Examples of the web used in the present invention include paper, synthetic paper, water-resistant paper, plastic films (films made of materials such as polyethylene, polypropylene, polyamide, polyethylene terephthalate, polyvinyl chloride, and nylon), and metals (aluminum, iron). , Copper, zinc, etc.), and a composite material composed of a metal and a plastic film and / or paper, but are not necessarily limited to these. Among these, aluminum thin plates, composite materials made of aluminum and other materials, copper thin plates, and composite materials made of other materials such as copper and plastic films are particularly advantageous.

The thickness of the web is not particularly limited, but a web having a thickness of about 0.01 mm to 1.0 is easy to handle.

e. Function The coating method of the present invention is a method in which a coating liquid is supplied from a slit to a coating surface of a web by extrusion at a coating amount equal to or more than a desired coating amount, and the coating amount is adjusted to a desired coating amount by a bar located next. . Therefore, in the extrusion, the application amount is not required to be very accurate, and it is sufficient to arbitrarily discharge a certain amount or more. In addition, since an apparatus that does not require much accuracy is sufficient, it is economical. Subsequently, the bar is applied while scraping to the desired amount of application, but at this time, since the application surface of the web is already covered with the application liquid discharged more than necessary, it is also possible to embrace bubbles. No vertical streaks due to air bubbles are generated.

Further, in the coating method of the present invention, the coating liquid discharged from the slit is scraped off by the bar at a position where turbulence does not occur immediately before the bar and flow unevenness does not occur. Therefore, in the coating method of the present invention, coating unevenness does not occur, and a coating film having a uniform film thickness is formed.

f. Examples Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these Examples unless it exceeds the gist.

In addition, Examples 1 to 4 and Comparative Examples 1 and 2 shown below
This was carried out using the coating apparatus shown in FIGS. Therefore, the following Examples 1 to 4 and Comparative Examples 1 and 2
This will be described with reference to FIGS.

Example 1 A web-like aluminum plate (material 1050) having a thickness of 0.24 mm and a width of 1000 mm was alkali-degreased, and the surface was polished with a nylon brush while applying a water suspension of permiston, and then thoroughly washed with water. Next, a 20% caustic soda solution of 70 ° C. was poured for 5 seconds, and the surface was etched. The surface was washed with running water, and an electrolytic solution comprising hydrochloric acid (35 g /), boric acid (20 g /), and aluminum ions (20 g /) was used. Electropolishing at 25 A / dm ² current density at 25 ° C. for 6 seconds, washing with water, then 70 ° C., 20%
The surface was etched by pouring off a sodium hydroxide solution, and then washed with water, and then subjected to anodizing treatment in a 10% sulfuric acid aqueous solution at 30 ° C. to form an oxide film of 2.5 g / m ² . Run the obtained aluminum plate 19 at 60 m per minute,
A coating liquid 20 composed of the following composition liquid is applied to the surface of the coating apparatus 11 through the slit 18 (slit width 100 μ) of the coating apparatus 11 shown in FIG.
Apply while discharging 00 ml, then at a position 30 mm away,
It was weighed with a wire bar 21 having a 0.2 mm diameter wire rotating at the same peripheral speed, and the excess coating solution 20 was scraped off and dried in the next drying oven 24.

Ester compound of naphthoquinone- (1,2) -diazide-5-sulfonic acid chloride and acetone pyrogallol resin 2.6 parts Cresol novolak resin 7.0 parts Naphthoquinone- (1,2) -diazide-4-sulfonic acid chloride 0.06 parts Oil blue 603 0.1 part Crystal violet 0.1 part Acetone 27 parts Propylene glycol monomethyl ether 27 parts The coated surface after drying was good without uneven coating.

The thickness of the photosensitive layer was 2.0 g / m ² .

Comparative Example 1 The same coating liquid 20 used in Example 1 was applied to a web-like aluminum plate 19 as in Example 1 using the apparatus shown in FIG. When the aluminum plate 19 traveled at a speed of 10 m / min or more, bubbles were generated vigorously on the application roller 1, and the application unevenness due to the bubbles could not be eliminated by the bar 5, and a good application surface could not be obtained.

Example 2 Anodized web-like aluminum plate made in the same manner as in Example 1 was further heated to 70 ° C. using a 5% potassium silicate solution.
For 10 seconds, washed with water and dried. The aluminum plate 19 thus obtained was run at 30 m / min, and a coating liquid 20 composed of the following composition was discharged onto the surface of the aluminum plate 19 using the coating apparatus 11 in the same manner as in Example 1, and 600 ml / min was discharged from the slit 18. Then, the mixture was weighed with a wire bar 21 having a 0.25 mm diameter wire rotating at the same peripheral speed, and the excess coating solution was scraped off and dried in the next drying oven 24. The coated surface after drying was good without coating unevenness. The thickness of the photosensitive layer was 1.8 g / m ² .

Acrylic copolymer (1) 30 parts Diazo photosensitizer (2-methoxy-4-hydroxy-5-benzoylbenzenesulfonate of 4-diazodiphenylamine and formaldehyde condensate) 3 parts Victoria Pure Blue BOH (Hodogaya Chemical) 1 part of oxalic acid 0.3 part Tetrahydrofuran 120 parts Ethylene glycol monomethyl ether 90 parts N-N-dimethylformamide 30 parts Methanol 60 parts The copolymer (1) was produced as follows.

Under a nitrogen stream, 150 g of dioxane was added with 0.3 g of azobisisobutyronitrile, and the mixture was heated to 80 to 85 ° C., and a mixture having the following composition was dropped therein while stirring.

2-Hydroxy-3-phenoxypropyl acrylate 40 g Methyl methacrylate 30 g Acrylonitrile 10 g Mono (2-methacryloxyethyl) hexahydrophthalate 20 g After completion of the dropwise addition, stirring was continued for another 5 hours, and dioxane 15 g
After adding 0 g, the mixture was poured into water to precipitate the copolymer. The precipitate was redissolved in 2-methoxyethanol, dropped into water, purified, and dried at 70 ° C. in vacuo to obtain a copolymer (1).

Example 3 In the same manner as in Example 1, a web-shaped aluminum plate was brush-polished, electrolytically etched, and anodized in a sulfuric acid electrolytic solution to obtain an aluminum plate 19 having an oxide film of 1.0 g / m ^2. Was. The aluminum plate 19 was run at a speed of 15 m / min, and a lithographic printing photosensitive liquid 20 for electrophotography having the following composition was applied to the surface of the aluminum plate 19 through the slit 18 at 55 m / min.
Coating was performed while discharging 0 ml, and then weighed with a wire bar 21 having a 0.5 mm diameter wire rotating at the same peripheral speed, scraping off excess coating liquid 20 and drying in the next drying oven 24.

 The above-mentioned β-type crystal form copper phthalocyanine 15 parts Styrene-maleic anhydride copolymer 65 parts Rose bengal 2 parts Ethylene glycol monomethyl ether 230 parts Toluene 230 parts The coated surface after drying was good without coating unevenness.

The thickness of the photosensitive layer was 5.0 g / m ² .

Comparative Example 2 Example 3 was applied to the web-like aluminum plate used in Example 3.
The coating solution used in (1) was applied using the coating apparatus shown in FIG. The coating liquid used here is likely to be uneven due to poor fluidity.
And the web 3 stayed at the contact 6, resulting in unevenness, which prevented good application.

Example 4 A web-like composite material 19 in which a 18 μm thick copper foil was bonded to a 1 m wide, 50 μm thick polyethylene terephthalate film
Is run at 35 m / min, and the same coating liquid 20 as in Example 1 is applied onto the surface of the copper foil while discharging 850 ml / min from the 100 μ slit 18, and then the 0.35 mm diameter rotating at the same peripheral speed is applied. It was weighed with a wire bar 21 having a wire, and the excess coating solution 20 was scraped off and dried in the next drying oven 24.
The coated surface after drying was good without coating unevenness. The thickness of the photosensitive layer was 3.5 g / m ² .

f. Effects of the Invention According to the present invention, from low-speed coating to high-speed coating, uniform coating without coating unevenness is possible.
It is possible to obtain a coating surface with no variation over the entire surface.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a coating device according to the present invention, FIG. 2 is a schematic diagram of a conventional coating device, and FIG. 3 is a schematic diagram of a conventional coating device that performs coating while forming a liquid pool.

Continuation of the front page (72) Inventor Takashi Okamoto 2-6-4 Chuo, Warabi City, Saitama Prefecture Inside Okamoto Kagaku Kogyo Co., Ltd. (56) References JP-A-58-223459 (JP, A) (58) Investigated Field (Int.Cl. ⁶ , DB name) B05C 5/00-5/04 B05D 1/26 B05C 11/00-11/10

Claims (2)

(57) [Claims] An extrusion mechanism for applying a coating solution to a belt-like support by discharging the coating solution from a slit, and a coating film having a desired film thickness applied to the belt-like support by the extrusion mechanism. And a gap between the slit and the scraping position of the bar, wherein the application liquid discharged from the slit does not cause turbulence immediately before the bar. A coating device having an interval of 10 to 200 mm that does not cause uneven flow. 2. A coating solution is applied to a continuously running belt-like support by discharging the coating liquid from a slit, and the coating liquid discharged from the slit does not cause turbulence immediately before the bar, and the flow is uneven. 10-200mm is a position that does not occur
And coating the coating solution with a bar to obtain a desired film thickness.