JP2000157912A - Applying and drying method of coating film having matted surface and device therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To manufacture a material having a matted surface in which a coating film and a mat have strong adhesive power and a stable surface uneven shape which causes no trouble with product appearance and is free from defects in performance by supplying powder before an applied coating film is dried to be touchable in a wet state to provide projecting and recessing parts on the surface. SOLUTION: A dissolving liquid is supplied as a photosensitive layer to a coater 20 from a dissolving liquid tank 11 by a pump 15 through a filter 16 and is applied onto a supporting body 1 wound on a back roll 2 and sent, and after that, when solvent is vaporized to some extent to increase solid concentration, before the photosensitive layer is completely dried to be touchable, matized particles are fed from a powder feeder 32, and furthermore, the photosensitive layer is successively dried by a dryer 30. The matized particles preferably have average particle size of 5-50 μm for the purpose of preventing spot like defects to the utmost and obtaining a stable surface uneven shape. And solid concentration of the photosensitive coating film at a point of time when powder is fed is preferably in the range of 30-90 wt.%.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a coating and drying method and a coating and drying apparatus for forming a coating film having a matted surface on a support.

[0002]

2. Description of the Related Art In a photosensitive material such as a photosensitive lithographic printing plate,
Matting the surface of a coating film of a material has been conventionally performed for the purpose of preventing adhesion between materials having a coating film (preventing sticking), imparting slipperiness of the coating surface, and imparting vacuum adhesion for contact exposure. Have been. Among them, a technique of matting the surface of a photosensitive layer of a photosensitive lithographic printing plate such as a PS plate to improve vacuum adhesion is particularly important. That is, in the plate-making process of preparing a printing plate using a photosensitive printing plate, in order to print the film original plate in close contact with the photosensitive printing plate, a film is generally placed between the glass plate and the rubber sheet of the printing frame using a vacuum printing frame. A method is used in which an original plate and a photosensitive printing plate are overlapped and sandwiched, and a vacuum is applied between the glass plate and the rubber sheet to make them adhere to each other (hereinafter, referred to as “vacuum adhesion method”). A photosensitive printing plate is known in which fine irregularities (hereinafter, referred to as "mats") are provided on the surface of a photosensitive layer to improve the adhesion by a vacuum adhesion method so that air on the contact surface can uniformly escape. For example, Japanese Patent Application Laid-Open No. Sho 51-111102 discloses a method of providing a coating layer composed of a fine pattern in which coated portions and non-coated portions are mixed on the surface of a photosensitive layer. Thermal fusion method, JP-A-56-9
No. 739 discloses a method in which particles are mixed and coated in a photosensitive solution, and JP-A-57-34558 discloses a method in which a mat is formed by spraying an aqueous solution in which a resin is dissolved or dispersed on the surface of a photosensitive layer to be coated. A method has been proposed.

[0003]

However, in the method of providing a mat on a photosensitive layer as disclosed in JP-A-51-111102, JP-A-55-12974, and JP-A-57-34558. In many cases, the adhesion between the photosensitive layer and the mat is problematic, and in the method of mixing particles in a photosensitive liquid as disclosed in JP-A-56-9739, a photosensitive liquid in which undissolved particles are mixed is used. Has the drawback that it is only possible to perform coarse filtration and it is difficult to completely remove unnecessary foreign substances from the liquid.At the time of drying, the liquid comes near the particles or repels, causing spot-like defects. It was easy.

SUMMARY OF THE INVENTION The present invention is directed to a method and an apparatus for coating and drying a coating film having a matte surface. It is an object of the present invention to produce a material having a matted surface which has no problem in product appearance and has no performance defects such as spot defects.

[0005]

This object is achieved by any of the following technical means (1) to (15).

(1) In a coating / drying method for forming a coating film having a matted surface on a support, powder is supplied before the applied coating film is dried in a wet state.
A method for applying and drying a coating film having a matte surface, characterized by providing irregularities on the surface.

(2) The average particle size of the powder to be supplied is 5
(1) The method for applying and drying a coating film having a matte surface according to the above (1).

(3) The coating having a matted surface according to (1) or (2), wherein the solid content concentration of the wet coating film at the time of supplying the powder is 30 to 90 wt%. The method of coating and drying the film.

(4) In a coating / drying apparatus for forming a coating film having a matted surface on a support, powder applied to the coating film surface is applied in a section from the application of the coating liquid by the coating apparatus to the drying of finger coating. A coating / drying device for a coating film having a matted surface, comprising a body feeding device, and a finishing drying device thereafter.

(5) In a coating and drying apparatus for forming a coating film having a matted surface on a support, a coating solution is applied by a coating apparatus, and then a powder supply device for supplying a powder to the coating film surface is provided in the drying apparatus. An apparatus for coating and drying a coating film having a matte surface, the coating apparatus being provided.

(6) In a coating and drying apparatus for forming a coating film having a matted surface on a support, a drying device is provided after a coating liquid is applied by the coating device, and then powder is supplied to the coating film surface. An apparatus for coating and drying a coating film having a matted surface, comprising an apparatus, and further provided with a drying apparatus for finishing.

(7) The mat according to any one of (1) to (3), wherein the coating having the matte surface is a photosensitive layer coating for a photosensitive lithographic printing plate. A method for applying and drying a coating film having a textured surface.

(8) The mat according to any one of (4) to (6), wherein the coating having the matted surface is a photosensitive coating for a photosensitive lithographic printing plate. Coating and drying equipment for coating films having a surface.

(9) In a coating and drying method for forming a coating film having a matted surface on a support, a coating solution containing substantially no undissolved material and a solution containing undissolved solid fine particles are simultaneously applied. A method for applying and drying a coating film having a matted surface.

(10) The solid fine particles have an average particle size of 3
(9) The method for applying and drying a coating film having a matte surface according to item (9), wherein the coating film has a matte surface.

(11) In a coating / drying apparatus for forming a coating film having a matted surface on a support, a coating solution having substantially no undissolved substance and an undissolved coating liquid are formed by using a die coater having two slits. A coating / drying apparatus for a coating film having a matted surface, wherein a liquid containing solid fine particles is discharged from each slit and two liquids are applied simultaneously.

(12) In a coating and drying method for forming a coating film having a matted surface on a support, the surface of the support is provided with surface irregularities having an average height of 3 to 20 μm, and then substantially undissolved matter is formed. A method for applying and drying a coating film having a matte surface, which comprises applying a coating solution free of a coating.

(13) A coating / drying apparatus for forming a coating film having a matted surface on a support is provided with a coating apparatus for forming surface irregularities having an average height of 3 to 20 μm, and thereafter substantially undissolved. An apparatus for applying and drying a coating film having a matte surface, comprising an application apparatus for applying an object-free coating solution.

(14) The matte coating according to the above (9), (10) or (12), wherein the coating having a matte surface is a photosensitive layer coating for a photosensitive lithographic printing plate. A method for applying and drying a coating film having a surface.

(15) The coated film having the matte surface according to the item (11) or (13), wherein the coating film having the matte surface is a photosensitive layer coating film for a photosensitive lithographic printing plate. Coating and drying equipment for coating film.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Among the above-mentioned problems, when the causes of these spot-like defects were examined, the phenomenon that the liquid around the particles approached or repelled was found to have a low initial coating viscosity after coating. It was found that this occurred because the coating film easily flowed in this state.

Therefore, there is a need for a method that ensures the adhesion between the photosensitive layer and the mat and does not cause spot-like defects. Specifically, as shown in the schematic diagram of the coating and drying apparatus 100 in FIG. 1, a solution as a photosensitive layer is supplied from a solution tank 11 to a coating apparatus 20 through a filter 16 by a pump 15 and wound around a back roll 2. Support 1
After the solvent is evaporated to some extent and the solid content concentration rises after the coating, the matted particles are supplied from the powder supply device 32 before the photosensitive layer is completely eroded and dried, and the photosensitive layer is further dried. And drying was continued.

The supplied matting particles preferably have an average particle size of 5 to 50 μm for the purpose of preventing spot-like defects as much as possible and for obtaining a stable surface unevenness.

Further, the solid content concentration of the coating film of the photosensitive layer at the time of supplying the powder is 30 to 90 wt% as shown in the graph of FIG.
Is preferably within the range. If the solid content concentration is too low, spot-like defects are liable to occur, and if it is too high, powder does not adhere and surface irregularities cannot be formed. Incidentally, the change in film thickness corresponding to the solid concentration distribution is as shown in the graph of FIG. 2, and it can be seen that both the concentration and the film thickness are still quite wet.

By incorporating the powder supply device 32 into the drying device 30, powder can be supplied during drying of the photosensitive layer. The type of the solvent for the photosensitive layer, the speed of transporting the support, and the like may vary depending on the type of the product, and the drying state of the coating film often differs. It is more preferable to have a mechanism capable of moving in the transport direction indicated by the arrow X. However, the drying device 3
In the case of 0, the high-temperature air may be partially circulated and used for the purpose of reducing energy loss, and in consideration of this, the powder supply device 32 is separately provided in a place that is not inside the drying device 30, and the powder supply device 32 is provided separately. It is preferable to provide the drying device 30 again after the supply device 32.

The powder supply device 32 is not particularly limited, and an existing rotary feeder system, table feeder system, screw feeder system or the like can be employed.

The photosensitive layer drying device 30 is not particularly limited, and a high-temperature air blowing system, an infrared irradiation system, a heating roll contact system, and the like can be employed.

The photosensitive composition applied here is not particularly limited. However, when a surfactant is contained in the photosensitive composition, spot-like defects tend to be particularly emphasized. The present invention works effectively. In addition, since the solvent in the photosensitive composition is dried quickly only with the quick-drying solvent alone, and it is difficult to arrange the powder supply device 32, it is desirable to include a solvent having a boiling point of 100 ° C. or higher.

The coating method of the photosensitive layer is not particularly limited, and typical coating methods include those using a coating apparatus 30 such as a roll coater, a die coater, and a wire bar coater.

On the other hand, the adhesion between the photosensitive layer and the mat can be ensured without any problem, as described in JP-A-56-9739, in which particles are mixed in the photosensitive layer. The photosensitive solution containing particles can only be filtered coarsely, and it is difficult to completely remove unnecessary foreign matter in the solution.If foreign matter is mixed in the photosensitive solution, the appearance of the product deteriorates. Or defects in quality performance.

In the present invention, in order to solve this problem, the present inventors have found a method for securing the adhesive force between the photosensitive layer and the mat and preventing the occurrence of foreign matter defects on the coating film.

More specifically, as shown in a schematic diagram of another example of a coating / drying apparatus 100A used in the present invention in FIG. 4, a photosensitive liquid having substantially no undissolved substance and a liquid containing undissolved solid fine particles are provided. Can be improved simultaneously by applying them separately at almost the same position. Separately, a solution tank 11 for a photosensitive solution containing no undissolved material and a solution tank 11A for a solution containing undissolved solid fine particles are prepared separately, and a photosensitive solution containing substantially no undissolved material is prepared. Is subjected to precise filtration by a filter 16 and then sent to a coating device 20 by a pump 15, and a solution containing undissolved solid fine particles is subjected to coarse filtration by a coarse filter 16 A and then to a coating device by a pump 15 A. 20
A is realized by sending the liquid to A. As a result, unnecessary foreign substances in the photosensitive liquid can be removed by filtration.

If the size of the solid fine particles is too large, spot-like defects are likely to appear on the coating film.
~ 20 µm is preferred.

As a method of simultaneously applying these two liquids, the two single-layer coating apparatuses 2 shown in FIG.
Various existing methods such as disposing 0 and 20A close to each other can be applied. However, as shown in a schematic diagram of another example of a coating and drying apparatus 100B used in the present invention in FIG. 5, a coating apparatus 20D having two slits is used. Each of the two liquids is applied to each of the tanks 1 using
1,11A, pump 15,15A, filter 16,1
It is particularly efficient and advantageous to discharge from each slit by 6A and apply two liquids simultaneously.

Further, regarding the adhesive strength between the photosensitive layer and the mat, which has been a problem in the conventional method of forming a mat on the photosensitive layer, a matte processing (roughening) is performed on the surface in advance, and then the photosensitive liquid is applied. It has been found that a strong adhesive force can be obtained by coating. If the photosensitive solution is subjected to precise filtration so that substantially no undissolved matter is present, foreign matter defects can be eliminated.
When the average height of the mat particles is higher than 20 μm,
Subsequent coating of the photosensitive layer tends to cause spot defects. If the average height is less than 3 μm, a desired surface unevenness cannot be obtained.

The mat processing method is not particularly limited, a method of providing a coating layer composed of a minute pattern in which coated portions and non-coated portions are mixed on the surface of the existing photosensitive layer, a method of thermally fusing a solid powder to a support, A method of providing a mat by spraying an aqueous solution in which a resin is dissolved or dispersed on the surface of the photosensitive layer is used. Further, similarly to the above, matting by applying a liquid containing undissolved solid fine particles can also be applied.

[0037]

EXAMPLES <Comparative Example 1> Thickness 0.3 mm, width 1000 m
After the surface of the m-type aluminum support was hydrophilized, a coating solution containing the photosensitive composition containing particles having an average particle diameter of 20 μm was applied using a roll coater as the coating apparatus 20. A fluorine-based surfactant is added to the photosensitive composition, and ethylene glycol monoethyl ether is used as a solvent. After the coating, the support was passed through a drying device 30 having a length of 20 m to blow air at 80 ° C. Coating was performed at a support speed of 30 m / min, a wet coating amount of 20 g / m ² , and a dry coating amount of 2 g / m ² during coating.

<Comparative Example 2> The photosensitive composition had an average particle size of 2
A coating liquid containing the same photosensitive composition as in Comparative Example 1 was applied except that the particles did not contain 0 μm particles, and a powder having an average particle diameter of 20 μm was placed on the photosensitive layer at a position 15 m from the entrance of the drying device 30. Sprayed. At a position 15 m from the entrance of the drying device 30, finger eclipse was dry.

Example 1 The photosensitive composition had an average particle size of 2
A coating solution containing the same photosensitive composition as in Comparative Example 1 was applied except that the particles did not contain 0 μm particles, and a powder having an average particle size of 20 μm was placed on the photosensitive layer at a position 5 m from the entrance of the drying device 30. Sprayed. The solid concentration of the coating film measured 5 m from the entrance of the drying device 30 was 25 wt%.

Example 2 The photosensitive composition had an average particle size of 2
A coating solution containing the same photosensitive composition as in Comparative Example 1 was applied except that particles of 0 μm were not included, and a powder having an average particle diameter of 20 μm was placed on the photosensitive layer at a position 6 m from the entrance of the drying device 30. Sprayed. The solid concentration of the coating film measured 6 m from the entrance of the drying device 30 was 31 wt%.

Example 3 The photosensitive composition had an average particle size of 2
A coating solution containing the same photosensitive composition as in Comparative Example 1 was applied except that the particles did not contain 0 μm particles, and a powder having an average particle diameter of 20 μm was placed on the photosensitive layer at 9 m from the entrance of the drying device 30. Sprayed. The solid concentration of the coating film measured 9 m from the entrance of the drying device 30 was 88 wt%.

Example 4 The photosensitive composition had an average particle size of 2
A coating solution containing the same photosensitive composition as in Comparative Example 1 was applied except that the particles did not contain 0 μm particles, and a powder having an average particle diameter of 20 μm was placed on the photosensitive layer at a position 10 m from the entrance of the drying device 30. Sprayed. The solid content concentration of the coating film measured 10 m from the entrance of the drying device 30 was 95 wt%.

Table 1 shows the results of counting spot defects having a size of 0.1 mm or more per 10 m of coating length and the results of evaluating the vacuum adhesion time in each of the above examples.

The evaluation criteria for the vacuum adhesion time were as follows: ○: a time in which the adhesion time was fast and the flatness could be ensured stably; ○: a time in which the adhesion time was slightly slow but the flatness was good and there was no problem in practical use; Those that are long and difficult to maintain flatness are marked with “x”.

[0045]

[Table 1]

As is evident from Table 1, in this embodiment, spot-like defects can be suppressed while ensuring vacuum adhesion.

Comparative Example 3 Thickness 0.3 mm, width 1000
After the surface of the aluminum support 1 was subjected to a hydrophilic treatment, a photosensitive solution containing solid fine particles having an average particle diameter of 10 μm was applied using a roll coater as a coating apparatus 30 for single-layer coating. The photosensitive solution containing the solid fine particles is a filter 16A.
After passing through a mesh filter having a filtration accuracy of 50 μm, the solution was fed to the roll coater. The transport speed of the support 1 is 30 m / min, and the wet weight at the time of coating is 2
0 g / m ^2, and dried by blowing 80 ° C. air after coating the support.

Comparative Example 4 Thickness 0.3 mm, width 1000
After the surface of the aluminum support 1 was subjected to hydrophilization treatment, an aqueous solution in which a resin was dissolved was sprayed onto the hydrophilized surface using an electrostatic spray gun to form hemispherical particles having a height of 22 μm. The liquid was applied using a single-layer coating roll coater as the coating device 20. The photosensitive solution contained no particles, and was passed through a cartridge filter having an absolute filtration accuracy of 5 μm as a filter 16 and then sent to the roll coater. The transport speed of the support 1 is 30 m / min,
The wet coating amount at the time of coating was 20 g / m ² , and the coating was dried by blowing air at 80 ° C. onto the support.

COMPARATIVE EXAMPLE 5 The same operation as in Comparative Example 4 was carried out except that the average height of the hemispherical particles formed by spraying with an electrostatic spray gun was 2 μm.

<Embodiment 5> Thickness 0.3 mm, width 1000
mm of aluminum support 1 after a surface hydrophilization treatment, a photosensitive solution containing no solid fine particles and an average particle size of 25 μm
20D of a liquid containing undissolved solid fine particles of
Was applied by a multilayer die coater. The photosensitive solution containing no solid fine particles was passed through a cartridge filter having an absolute filtration accuracy of 5 μm as a filter 16 and then sent to the multilayer die coater. The liquid containing the solid fine particles was passed through a mesh filter having a filtration accuracy of 50 μm as the filter 16A, and then sent to a coater. The transport speed of the support 1 was 30 m / min, the wet weight at the time of coating was 20 g / m ² , and air at 80 ° C. was blown onto the support 1 after coating to dry.

Example 6 The average particle size of the solid fine particles was 10
The coating was performed under the same conditions as in Example 5 except that the thickness was set to μm.

Example 7 The average particle size of the solid fine particles was 2 μm.
The coating was carried out under the same conditions as in Example 5 except that m was used.

Example 8 The same operation as in Comparative Example 4 was carried out except that the average height of hemispherical particles formed by spraying with an electrostatic spray gun was 15 μm.

Example 9 The same operation as in Comparative Example 4 was carried out except that the average height of hemispherical particles formed by spraying with an electrostatic spray gun was 4 μm.

Table 2 shows the results of counting the total number of foreign matter defects and spot-like defects having a size of 0.1 mm or more per 10 m of coating length and the evaluation results of the vacuum adhesion time in each of the above examples. The evaluation criteria for the vacuum adhesion time were the same as those in Table 1.

[0056]

[Table 2]

As is evident from Table 2, in each embodiment of the present invention, spot-like defects can be suppressed while ensuring vacuum adhesion.

[0058]

According to the present invention, a coating and drying method and a coating and drying apparatus for forming a coating film having a matte surface on a support have been established, and the coating film and the mat have a strong adhesive force and a desired surface. Unevenness is obtained, defects such as adhesion of fine foreign matter are eliminated, and coated products with high quality matte surface without defects in product appearance and performance such as spot-shaped defects are stably obtained. became.

[Brief description of the drawings]

FIG. 1 is a schematic view of an example of a coating and drying apparatus used in the present invention.

FIG. 2 is a graph showing a change in film thickness during the drying process after application.

FIG. 3 is a graph showing a change in solid content concentration during drying after coating.

FIG. 4 is a schematic view of another example of the coating and drying apparatus used in the present invention.

FIG. 5 is a schematic view of another example of the coating and drying apparatus used in the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 support 2 back roll 11 dissolving tank for photosensitive solution without undissolved substance 11A dissolving tank for solution containing undissolved solid fine particles 15, 15A pump 16, 16A filter 20, 20A, 20D Coating device 30 Drying device 32 Powder supply device 100, 100A, 100B Coating and drying device

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) B41N 1/14 B41N 1/14 3/04 3/04 G03F 7/00 503 G03F 7/00 503 7/09 501 7/09 501 7/11 501 7/11 501 // B05C 19/02 B05C 19/02 F term (reference) 2H025 AB03 DA06 DA20 EA10 2H096 AA06 CA03 CA05 CA20 LA30 2H114 AA04 AA11 AA23 AA27 BA01 DA75 DA78 DA80 EA02 EA02 GA03 4D075 AA01 AC03 AC72 AE06 DA04 DB07 DC27 EA02 EA10 EB57 EC53 4F042 AA22 AB06 DB18 DB25 ED02

Claims (15)

[Claims] In a coating and drying method for forming a coating film having a matte surface on a support, powder is supplied before the applied coating film is dried by finger erosion in a wet state, and irregularities are formed on the surface. A method for applying and drying a coating film having a matted surface. 2. The powder to be supplied has an average particle size of 5 to 50.
2. The method for applying and drying a coating film having a matted surface according to claim 1, wherein the coating film has a thickness of μm. 3. The coating and drying method according to claim 1, wherein the solid content of the wet coating film at the time of supplying the powder is 30 to 90 wt%. Method. 4. A coating / drying apparatus for forming a coating film having a matted surface on a support, wherein a powder applied to the coating film surface is applied in a section from application of a coating liquid by the coating apparatus to finger-drying. A coating and drying apparatus for a coating film having a matted surface, comprising a supply device, and a finishing drying device thereafter. 5. A coating and drying apparatus for forming a coating film having a matted surface on a support, after applying a coating liquid with the coating device, providing a powder supply device to the coating film surface in the drying device. An apparatus for coating and drying a coating film having a matte surface. 6. A coating and drying apparatus for forming a coating film having a matted surface on a support, wherein a drying device is provided after a coating liquid is applied by the coating device, and then a powder supply device to the coating film surface is provided. , Followed by a drying device for finishing, wherein the coating and drying device has a matted surface. 7. The coating having a matted surface according to claim 1, wherein the coating having the matted surface is a photosensitive layer coating for a photosensitive lithographic printing plate. Coating and drying method of coating film. 8. The coated film having a matted surface according to claim 4, wherein the coated film having a matted surface is a photosensitive layer coating film for a photosensitive lithographic printing plate. Coating and drying equipment for coating film. 9. A coating and drying method for forming a coating film having a matted surface on a support, wherein a coating solution containing substantially no undissolved matter and a liquid containing undissolved solid fine particles are simultaneously applied. A method for applying and drying a coating film having a matte surface, characterized by the following. 10. The solid fine particles having an average particle size of 3 to 20.
The method for applying and drying a coating film having a matted surface according to claim 9, wherein the coating film has a thickness of μm. 11. A coating and drying apparatus for forming a coating film having a matted surface on a support, using a die coater having two slits, using a coating liquid having substantially no undissolved substance and an undissolved solid. A coating and drying apparatus for a coating film having a matte surface, wherein a liquid containing fine particles is discharged from each slit and two liquids are applied simultaneously. 12. A coating and drying method for forming a coating film having a matted surface on a support, wherein after applying a surface unevenness having an average height of 3 to 20 μm on the support, a substantially undissolved substance is formed. A method for applying and drying a coating film having a matte surface, characterized by applying a coating liquid that does not have a matte surface. 13. A coating and drying apparatus for forming a coating film having a matte surface on a support, wherein the coating layer has an average height of 3 to 3.
A coating and drying device for a coating film having a matte surface, comprising a coating device for forming a 20 μm surface unevenness, followed by a coating device for coating a coating solution having substantially no undissolved matter. 14. The coating film having a matted surface according to claim 9, 10 or 12, wherein the coating film having a matted surface is a photosensitive layer coating film for a photosensitive lithographic printing plate. Coating and drying method. 15. A coating film having a matted surface according to claim 11, wherein the coated film having a matted surface is a photosensitive layer coating film for a photosensitive lithographic printing plate. apparatus.