JPH0446342A - Production of photosensitive printing plate - Google Patents

Abstract

PURPOSE:To obtain the coating method which can extremely lessen the mixing between layers which arises at the time of forming the photosensitive printing plate having a multilayered structure by successively electrostatically sticking the particles of a coating liquid to form the photosensitive coating film of the next layer after the formation of a specific layer. CONSTITUTION:A base 1 travels first while the base is guided by pass rollers 2, 3. The 1st layer is formed on the surface of the base by a roll coater 18 and is lightly dried in a drying zone 8. The 2nd layer of the coating film is then formed on the surface of the 1st layer by a blow-off port 4a and is lightly dried in a drying zone 9. The 3rd layer of the coating film is formed on the surface of the 2nd layer by a blow-off port 4b and is completely dried in a drying zone 10. The complete drying of the coating film layers including the residual solvents is merely necessitated to be executed finally after the final coating film layer is formed according to this constitution and therefore, the continuous formation of the multilayered coating films with compact equipment is possible.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for manufacturing a photosensitive printing plate, and particularly to a coating method for forming two or more coating layers in succession.

[Conventional technology]

Conventionally, photosensitive printing plates have mainly been composed of one layer, and have been manufactured by methods such as wheeler coating, roll coating, bar code coating, and bead coating.

On the other hand, Special Publication No. 53-36364, Special Publication No. 50-748
No. 1, Japanese Patent Application Laid-open No. 50-133008, DAS No. 1
, 671.626, etc., various configurations of photosensitive printing plates with a multilayer configuration have been disclosed, and their manufacturing methods include wheeler coating, roll coating, gravure coating, and bead coating. A photosensitive printing plate with a multilayer mechanism was prepared by coating and drying the lower layer using a method such as the following, and then coating and drying the upper layer.

[Problem to be solved by the invention]

Although several methods for producing photosensitive printing plates having a multilayer structure as described above have been proposed, they have been insufficient in the following points.

In other words, in the Wheeler coating method, a thick film is expanded by centrifugal force, so during the expansion process, especially when the type of solvent in the upper and lower layers is the same, the lower layer is easily dissolved by the upper layer liquid, and the structure in which the upper and lower layers are separated is Obtaining membranes was difficult.

Next, when using a method such as roll coating or gravure bar coating, the upper and lower layers are coated with the same solvent in order to apply the coating by contacting the film surface of the coating layer with a coating roll, gravure roll, bar, etc. When coating, there is a risk of dissolving or, in severe cases, destroying the underlying surface, and the range of use is extremely limited.

Furthermore, when bead coating is used, although it is improved over the above method, when the same type of solvent is used for the upper and lower layers, it is necessary to avoid swelling or dissolving the lower layer between coating and drying. I could say that it was a sufficient method.

Therefore, conventionally, when forming a coating film with a multilayer structure while maintaining separation between the eyebrows, it is important to first use a solvent that has at least a low mutual solubility; , roll coat gravure coat bar coat,
It was difficult to create a multilayer film using bead coating or the like.

The object of the present invention is to provide a coating method which minimizes these problems of the prior art, namely, the glabella mixing that occurs when making a multilayered photosensitive printing plate.

[Means and effects for solving the problems] The above objects of the present invention can be achieved by the following method for producing a photosensitive printing plate.

That is, in a method for producing a photosensitive printing plate in which a plurality of layers of photosensitive coating liquid are applied on a support, particles of the photosensitive coating liquid are sequentially electrostatically deposited after forming a specific layer to form the next layer of photosensitive coating. This is a method for producing a photosensitive printing plate characterized by forming a film.

In the present invention, the lower coating layer is roll coated.

It can be coated by conventionally known means such as Clavia coat, bar code, bead coat, etc., and it can also be coated by using the IHt1 cloth method shown below, which is used for the upper layer.

In the present invention, the upper layer coating liquid is applied as follows.

That is, the coating liquid can be atomized into particles of the coating liquid using various atomization devices such as a rotary bell, a spray nozzle, and an ultrasonic atomization device.

As a method for charging the coating liquid particles in the atomized state, the coating liquid particles may be charged before the blower outlet after the coating liquid is atomized, or may be charged after the blower outlet.

Preferred embodiments of the present invention will be explained with reference to the drawings.

FIGS. 4 and 5 show examples of the static coating method used in the present invention, in which the coating liquid is atomized in advance and then charged to obtain particles of the coating liquid in an atomized state and charged. It is a schematic sectional view of the process of electrostatically adhering particles of the coating liquid to a support to form a coating layer.

In FIG. 4, the coating liquid is applied by an ultrasonic atomizer 16.
In FIG. 5, coating liquid particles are atomized in an atomization chamber 12 by an atomization device 11 such as a rotating bell or a spray nozzle. The coating liquid particles are carried by the carrier gas 17 from the atomization chamber through the transport pipe 5 and reach the outlet 4 which is the opening. Among the coating liquid particles, particles having a large diameter collide with the walls of the atomization chamber 12 and the transport pipe 5 before reaching the blow-off port 4 and are removed. The viscosity of the particles increases due to evaporation of the solvent in the particles up to the outlet 4. The coating liquid particles that have reached the outlet 4 are charged by the electrode 7 and electrostatically adhered to the support 1, thereby forming a coating film having a uniform thickness on the support 1. The support 1 runs guided by bus rollers 2 and 3.

FIG. 2 is a perspective view of the vicinity of the air outlet 4 in FIGS. 4 and 5. FIG. The outlet 4 having the electrode 7 is rectangular, and particles of the atomized coating liquid are charged by the electrode 7 and electrostatically adhere to the support in a laminar flow state to form a coating layer. Ru. There are no detailed restrictions on the shape of the air outlet 4;
The cross section of the cross section may be rectangular as shown in Fig. 3(a), it may be rectangular with rounded short sides as shown in Fig. 3(b), or it may have a rectangular shape with rounded short sides as shown in Fig. 3(C). It may also be a long and narrow oval shape.

For example, as shown in Figure 2, the electrode is of a type that extends linearly along the long side of the rectangle, goes slightly inside the rectangular cross section, and has the electrode end outside the rectangle. It is not limited to. The other end of this electrode is
It is connected to a high voltage generator via an electrode cable 6, and a voltage of several tens of kilovolts is applied thereto.

FIGS. 1(a) and 0) are schematic cross-sectional views of the process of forming two or more coated film layers of the present invention on a support, respectively.

The blow-off ports 4a, 4b and 4C are each similar to the blow-off port 4 shown in FIG. First, FIG. 1 (4), in which a coating film layer can be formed, will be explained. The support 1 is guided by X rollers 2 and 3 and runs. A first layer is formed on the surface of the support by the roll coater 18 and lightly dried in the drying zone 8.

Next, a second coated film is applied to the surface of the first layer through the air outlet 4a.
A layer is formed and lightly dried in drying zone 9. Furthermore, a third coated layer is formed on the surface of the second layer through the blow-off port 4b and is completely dried in the drying zone 10.

In the above-mentioned coating drying process, drying lightly means that drying in drying zones 8 and 9 is sufficient as long as the film surface is dry, and residual solvent can be controlled in drying zone 10. , the length of drying zones 8 and 9 is 1
Compared to 0, if the same amount of coating is applied by each coating device, it can be considerably shortened.

Also, depending on the degree of prevention of mixing of each layer, the first layer, the second layer
The layer does not dry completely, but remains semi-dry for at least several hundred c.
In some cases, it is sufficient to have a film surface viscosity of about p.

Next, FIG. 1(b) will be explained. The support 1 is guided by a bahi roller 2 and runs. A first layer of coating film is formed on the surface of the support through the air outlet 4a, and is lightly dried in the drying zone a. On the surface of the first layer, an air outlet 4 is provided.
A second layer of the coating film is formed by b and is lightly dried in the drying zone 9. Furthermore, a third coating film layer is formed on the surface of the second layer by the blower outlet 4C, and is completely dried in the drying zone 10.

According to the present invention, after forming the last coating film layer, it is only necessary to completely dry the coating film layer including the residual solvent, and therefore, it is possible to continuously form a multilayer coating film using compact equipment. I can do it.

The degree of drying of each layer can be appropriately selected depending on the required degree of separation between layers.

In addition, in order to improve the degree of separation between layers, it is necessary to
, 4c, etc., and it is necessary to control the diameter and viscosity of the droplets that are blown out and adhere to the film surface. In other words, if the droplet diameter is too large, it will melt the underlying film surface and the droplet diameter will be 50%.
It should be on the order of μm.

Similarly, if the viscosity of the droplets is too low, it increases the mixing with the lower layer, so the viscosity of the liquid is preferably 5 cp or more. Also, if the viscosity is too high, that is, 100 cp or more, the smoothing of the film will be difficult. It is difficult to form a multilayer film, however,
If two or more layers are applied and the lower layer is not completely dry, the coating may spread smoothly even if the coating is 100 cρ or more.

A wide variety of coating liquids can be used in the present invention, whether aqueous or non-aqueous, as long as they can be atomized.

As a water-based coating liquid, for example, Japanese Patent Publication No. 61-28986
Copolymers of acrylic esters and acrylic acid or methacrylic acid as described in the above publication; Copolymers of styrene, acrylic esters, acrylic acid or methacrylic acid; Copolymers of acrylic esters, styrene, acrylonitrile, etc. and acrylic acid Alternatively, a copolymer of methacrylic acid, maleic acid, itaconic acid, etc.; a resin such as a vinyl polymer such as polyvinyl alcohol, polyvinyl acetate, or polyvinylpyrrolidone is appropriately selected and dissolved or dispersed in water by a conventionally well-known method. There is a coating liquid available.

Similarly, organic solvent-based coating liquids contain many resins.
For example, vinyl chloride-vinyl acetate copolymer acetal resin, vinyl acetate-based pJ resin, and urethane resin.

Resins such as acrylonitrile butadiene resin are melted using ester-based solvents such as methyl acetate, ethyl acetate, butyl acetate, and ethyl lactate, ketone-based solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone, and n-
There are solutions in which it is dissolved in isobutanol, quijirol, etc.

Other resins include natural resins such as shellac and rosin; 5, such as phenol formaldehyde resin;
Novolac type phenolic resins such as m-cresol formaldehyde resins 1, for example polyacrylic acid.

Polymethacrylic acid, methacrylic acid-styrene copolymer,
Homopolymers of unsaturated carboxylic acids such as methacrylic acid-acrylic acid-methyl copolymers, styrene-maleic anhydride copolymers or copolymers of these with other copolymerizable monomers, polyvinyl acetate Examples include resins and polyhydroxystyrenes in which partially or completely saponified products are partially acetalized with aldehydes such as acetaldehyde, benzaldehyde, hydroxybenzaldehyde, and carboxybenzaldehyde. Furthermore, there are also organic solvent soluble resins including cellulose alkyl ethers such as cellulose methyl ether and cellulose ethyl ether.

Water, alcohols like methanol, ethanol, ethylene glycol monomethyl ether, ethylene glycol monomethyl ether acetate.

Dimethylformamide, diethylformamide.

A coating liquid can also be prepared by using dichloroethane, methyl ethyl ketone, cyclohexanone, toluene, etc. alone or in combination as a solvent to dissolve or disperse one or more of the above resins.

The form of the support is, for example, sheet-like or plate-like;
Materials for the support include paper; for example, paper coated with heat-fusible plastics such as polyethylene, polypropylene, and polystyrene, aluminum, various aluminum alloys, metal plates such as zinc, iron, copper, etc., such as cellulose diacetate. , cellulose butyrate, cellulose acetate butyrate, cellulose propionate, cellulose triacetate, cellulose nitrate.

They include plastic films such as polyethylene terephthalate, polypropylene polycarbonate, polyvinyl acecool, etc.; and plastic films coated with the metals described above by lamination or vapor deposition.

〔Example〕

Examples are shown below to further clarify the effects of the present invention.

Example-1 An aluminum plate with a thickness of 0.24 mm was degreased by immersing it in a 7% aqueous solution of trisodium phosphate (liquid temperature 60"C) for 3 minutes, and after washing with water, Bumis was suspended on its surface. While pouring the water, rub with a nylon brush to make a sand stand. After washing with water, sodium silicate (S i Ox /N
ag O-3,1 to 3.3 (molar ratio)) in a 5% aqueous solution (
The sample was immersed in a liquid temperature of 70°C for 30 to 60 seconds. Subsequently, it was thoroughly washed with water and dried.

Apply 0.3 g/nl of a solution with the following composition A to this aluminum plate by roller coating, dry lightly until the film surface is dry, and then apply a solution with the following composition (same solution as Solution A except for the dye). As shown in FIG. 1(a), the coating was applied by the method according to the present invention and dried to obtain a dry film having a weight of 1.8 g/I.

This sample is called ■. For comparison, liquid C was prepared by roll coating so that the dry film contained the same amount of dye and other solids as sample ■, and was dried.
made.

Solution A: 2-hydroxyethyl methacrylate copolymer (1) (as described in Example 1 in U.S. Pat. No. 4,123,276, 0.87 g P-diazodiphenylamine and 2-methoxy-4hydroxy-5-benzoylbenzenesulfonate, a condensate of formaldehyde...0.1g methanol...6g 2-methoxyethanol...6g Liquid B; 2-hydroxyethyl methacrylate copolymer (1 ton) (As described in Example 1 in U.S. Pat. No. 4,123,276) ...0.87 g 2-methoxy-4-hydroxy-5 condensate of P-diazodiphenylamine and paraformaldehyde -Benzoylbenzenesulfonate...0.1g Oil Blue #603 (Blue dye from Orient Chemical Industry)...0.036g Methanol...6g 2-methoxyethanol...68C liquid; 2-hydroxyethyl methacrylate Copolymer (1) (as described in Example 1 in U.S. Pat. No. 4,123,276)...0.87 g 2-methoxy of the condensate of P-diazodiphenylamine and paraformaldehyde -4-Hydroxy-5-benzoylbenzenesulfonate...0.1g Oil Blue #603 (blue dye from Orient Chemical Industry ■)...0.03g Methanol...6g 2-methoxyethanol...6g sample at 40°C18
After being left at 0% RH for 5 days and exposed to light, the color of U.S. Patent No. 4.
The plate-making process was carried out in the same manner as in Example 1 described in No. 123.276.

When printing was carried out using the obtained lithographic printing plates ■ and ■, the printed matter printed by the printing plate ■ had background stains, whereas the printed matter printed by the printing plate ■ had no stains at all. I couldn't see it.

In addition, there was almost no difference in other printing performances such as printing durability between ■ and ■.

〔Effect of the invention〕

By the method for producing a photosensitive printing plate of the present invention, a photosensitive printing plate of excellent quality can be produced without mixing between the eyebrows. Furthermore, since multilayer coating can be performed continuously, equipment costs are reduced, and costs can be reduced by improving productivity.

[Brief explanation of drawings]

FIG. 1 is a side view of an embodiment of the method for producing a photosensitive printing plate of the present invention, FIG. 2 is a perspective view illustrating a blow-off port for coating liquid particles used in the present invention, and FIG. 3 is a view showing various types of the blow-off port. FIGS. 4 and 5 are side sectional views of an embodiment of a mechanism for producing coating liquid particles used in the present invention. 1. Support 2, 3. Bath rollers 4.4a, 4b
, 4c - Air outlet 5... Transport pipe 6... Electrode cable 7.7a, 7b, 7c - Electrode 8.9.10... Drying zone 11... Spray device 12... Spray chamber 13.14.15 ...Cross-sectional view of the air outlet I6...Ultrasonic atomizer 17...Carrying gas 1 day...Roller coater (a) (b) (c) Figure 4 Figure 5 Procedures (Hoshosho November 15, 1990) Day

Claims (1)

[Claims] In a method for producing a photosensitive printing plate in which multiple layers of a photosensitive coating solution are applied to a support, particles of the photosensitive coating solution are sequentially electrostatically deposited after forming a specific layer to form the next layer of photosensitive coating film. A method for producing a photosensitive printing plate, characterized by forming a photosensitive printing plate.