JPS6223305B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for making a dry lithographic printing plate.

Lithographic printing, which is the mainstream of today's printing, skillfully takes advantage of the contradictory properties of water and oil-based ink.
Printing is carried out by alternately bringing water and ink into contact with a planographic plate consisting of a hydrophilic non-image area and an oleophilic image area, so that the ink adheres only to the image area. In this case, it is difficult to control the dampening water that serves to prevent ink from adhering to non-image areas, and the use of dampening water has become a major problem in terms of printing suitability and printing effectiveness. Therefore, various attempts have been made to print using a lithographic plate without supplying water or other liquid polar substances to the non-image area during printing. Among them, there is a dry lithographic printing method (US Patent No. 3511178) in which a non-adhesive thin film is provided in the non-image area, but this plate-making method has various difficulties in practical application and is not actually used. .

The present inventors first used a printing plate having an image protection substance in the printing area, applied a non-adhesive thin film to the entire surface of the printing plate, and then added the image protection substance and the non-adhesive film applied thereon. In this method, ethylene glycol acetate is mainly used as a solvent to remove the image protection substance and the non-adhesive thin film applied thereon. An ether ester such as monoethyl ether was used to swell the non-adhesive film while removing the image protection material and the non-adhesive film thereon. However, the ether ester solvent slightly deteriorates the non-adhesive thin film in the non-image area, causing a deterioration in the printing durability of the plate. Another disadvantage was that the developing operation took a considerable amount of time.

Therefore, the inventors of the present invention conducted further research and discovered that an alcohol-based solvent can be used to remove the non-adhesive thin film in the image area, and that it is easy to develop, the development time can be greatly shortened, and it has a long printing life. A method for making dry lithographic printing plates with vastly improved power has been obtained. That is, in the present invention, a positive type film is applied to a plate having a photodegradable photosensitive layer, exposed to light, and a plate having an image protective substance in the developed image area is used, and the entire surface of the plate is coated with a non-adhesive substance. Before applying a thin film of non-adhesive material to the entire surface of the plate in the dry lithography process, in which a thin film of non-adhesive material is applied over the entire surface of the plate, the image protection material and the thin film of non-adhesive material applied thereon are removed. Alternatively, a plate-making method can be used that involves later exposing the entire surface of the image protection material in the image area to photodecomposition, and removing the image protection material and the thin film of non-adhesive material applied thereon with a solvent. be.

The plate having an image protection substance in the image area used in the present invention is a plate having a photodegradable photosensitive layer in the image area, and is a commercially available positive type PS plate (photosentized plate) or a positive type plate. A type wipe-on plate or the like is used, a positive type film is applied to the plate, the non-image areas are exposed, and the plate is photodecomposed and developed.

The photosensitive material used in the photodegradable photosensitive layer is a combination of orthoquinone diazites or a photosensitive azine compound such as diphenylamine-4-diazonium and a heteromultiacid such as phosphotungstic acid.

Preferred materials for forming the non-adhesive thin film used in the present invention include polysiloxanes such as silicone varnish, silicone oil, and silicone rubber, and fluorine-containing polysiloxanes such as fluorine rubber. These non-adhesive substances may not have sufficient adhesion to the printing plate by physical adhesion using grains alone, so it is advantageous to treat the printing plate with an anchoring agent in advance. As this anchoring agent, a silane coupling agent is usually effective.

In the present invention, before or after applying a non-adhesive thin film, the image protecting material in the image area is exposed to light and photodegraded, but the image protecting material is exposed to light before or after applying the non-adhesive thin film. It is more advantageous to dissolve the image area more efficiently. The image area becomes easily soluble in lower alcohols such as ethanol, methanol, and isopropyl alcohol through photolysis, so development becomes easy and the development time is significantly shortened. In addition, since lower alcohol solvents such as ethanol can be used during development, the non-adhesive thin film that is the non-image area will not deteriorate.
A dry lithographic printing plate with excellent printing durability can be obtained. Furthermore, it is economical because cheap solvents such as lower alcohols can be used. The solvent used in the development is preferably the alcohol mentioned above, but is not limited thereto, and glycol ether, glycol ether ester, etc. can also be used.

In addition, in the method of the present invention, it is advantageous to apply a heat treatment at 160°C to 210°C for 1 to 5 minutes after applying the nonadhesive thin film, since the resistance of the nonadhesive thin film can be increased. . In addition, when applying the non-adhesive thin film after exposing the image area, the heat treatment at this time is
Heat treatment can be performed as is, and the work of exposing the image area can be done easily, but when exposing the image area after applying a non-adhesive thin film, it is necessary to expose the image area in advance and then heat the image area. If the entire printing plate is exposed to light after heating, the image area will not be removed successfully. In addition, if the entire surface of the printing plate is exposed to light without heat treatment after applying a non-adhesive thin film, it may take time to dry the non-adhesive thin film, or it may be troublesome to handle the non-adhesive thin film in an undried state. There is no difference in effectiveness.

Some of the advantages of the present invention are as follows.

1. Since a dry lithographic printing plate can be made using a printing plate made by the current lithographic plate-making method as a base, there are no problems in plate-making and printing.

2. Plate making operations are easy and plates of stable quality can always be obtained.

3. Since the grained metal is used as the marking line, printed matter with good printing durability, good ink adhesion, and good printing effect can be obtained.

4. Since the current plate-making method is used as a means of image composition, it is versatile and allows for free registration, tone reproduction, and correction during printing.

Next, the present invention will be specifically explained using examples.

Example 1 A positive film was applied to a photodegradable PS plate (positive SGP plate (manufactured by Fuji Film), exposed, and then the entire surface of the developed plate was exposed to light to completely photodecompose the photosensitive layer in the image area. Made by Toray Silicone KK
SH9145RTV (polysiloxane) with dry film 5
SH9145RTV was cured by coating to a micron thickness and heating at 180°C for 3 minutes. After that, it was moistened with ethanol for about 2 minutes and was easily developed by rubbing lightly with a pad. Using the obtained dry planographic printing plate, 100,000 copies were printed on a Heidel KORD offset printing machine without water supply, and no problems occurred.

Example 2 In the same manner as in Example 1, a positive film was applied to a photodegradable PS plate (positive type lith coated positive (Fuji Pharmaceutical Co., Ltd.)), exposed, and then developed. The entire surface of the plate was exposed to light, and the photosensitive layer of the image was completely photodecomposed. Furthermore, the print was coated with a dry film of SH9145RTV manufactured by Toray Silicone Co., Ltd. to a thickness of 5 microns, and heated at 180°C for 3 minutes to cure the SH9145RTV. After that, it was moistened with ethanol for about 3 minutes and was easily developed by rubbing lightly with a pad. Using the obtained printing plate, 100,000 copies were printed on a Heidel KORD offset printing machine without water supply, without causing any problems.

Example 3 A photosensitive solution of Quitsu Quipon Positive Type (manufactured by Ueno Chemical Industry Co., Ltd.) was applied to a smoothed aluminum plate, and the plate was made using the usual method for making a Wipon plate. The entire surface of the plate was exposed to light, and the photosensitive layer of the image was completely photodecomposed. Furthermore, the plate surface was coated with a dry film of SH9145RTV to a thickness of 5 microns, and heat treated at 180℃ for 3 minutes.
Hardened SH9145RTV. After that, it was moistened with ethanol for about 2 minutes and was easily developed by rubbing lightly with a pad. Using the obtained printing plate, Heidel
I printed 100,000 sheets on a KORD offset press without water supply and had no problems.

Example 4 Photodegradable plate made for current lithographic printing
PS version (Positive SGN version (manufactured by Fujifilm))
The developing ink and gum arabic film on the plate surface were removed using a . The entire plate was exposed to light to completely decompose the photosensitive layer of the image. Furthermore, the plate is made of Toray silicone.
SILASTJC733RTV (Futuso Rubber) was coated with a dry film to a thickness of 7 microns, and the 733RTV was cured by heat treatment at 200°C for 5 minutes. After that, it was moistened with isopropyl alcohol for 2 minutes and was easily developed by rubbing lightly with a pad. Using the obtained dry planographic printing plate, 100,000 sheets were printed on a Heidel KORD printing machine without water supply, and no problems occurred.

Example 5 As in Example 4, the development ink and gum arabic film on the plate surface were removed using a photodegradable PS plate re-coat positive. This plate was coated with a dry film of SH9145RTV to a thickness of 5 microns, and then the plate was exposed to light to completely photodecompose the photosensitive layer of the image at 180°C.
SH9145RTV was cured by heat treatment for 3 minutes.
Thereafter, it was wetted with butyl carbitol acetate for 3 minutes, rubbed lightly with a patch, and developed. Using the obtained printing plate, 50,000 copies were printed on a Heidel KORD offset printing machine without water supply and no problems occurred.

Example 6 In the same manner as in Example 5, a photodegradable PS plate re-coat positive was used to remove the development ink and gum arabic film from the plate surface. The entire surface of the plate was exposed to light, and the photosensitive layer of the image was completely photodecomposed. Furthermore, the plate surface was coated with a dry film of SH9145RTV to a thickness of 5 microns.
SH9145RTV was cured by heat treatment at 180°C for 3 minutes. Thereafter, it was wetted with butyl carbitol acetate for 3 minutes, and developed by rubbing lightly with a patch. Using the resulting printing plate, 45,000 copies were printed on a Heidel KORD offset printing machine without water supply, without any problems occurring. However, after printing 50,000 sheets, stains started appearing in non-print areas. When the surface of the printing plate was examined, there were some areas where the silicone layer had peeled off.

Comparative Example 1 A positive film was applied to a photodegradable PS plate (SGP plate) and exposed and developed. Without exposing this plate to light, a dry film of SH9145RTV was coated on the plate surface to a thickness of 5 microns, and heat treated at 180℃ for 3 minutes.
Hardened SH9145RTV. After that, it was wetted with methyl carbitol acetate for 15 minutes, rubbed with a patch and developed. Using the obtained printing plate, Heidel
Staining began to occur after printing 30,000 sheets with the KORD offset printing machine without water supply. When I examined the plate, I found that the silicone layer had worn away.

Comparative Example 2 Development was attempted using ethanol and isopropanol instead of methyl carbitol acetate in Comparative Example 1, but development was not possible even after 15 minutes of wetness.

Claims (1)

[Scope of Claims] 1. A positive type film is applied to a plate having a photodegradable photosensitive layer, exposed to light, and a plate having an image protection substance in the developed image area is used, and the entire surface of the plate is coated with non-adhesive material. In the dry lithography process, a thin film of a non-adhesive material is applied over the entire surface of the plate, and then the image protection material and the thin film of a non-adhesive material applied thereon are removed. A dry method consisting of exposing the entire surface of the image protection material in the image area to light, photodegrading it, and removing the image protection material and the thin film of non-adhesive material applied thereon with a solvent before or after application. How to make a lithographic plate. 2 After exposing the entire surface of the image protection substance in the image area, apply a thin film made of a non-adhesive substance to the entire surface of the plate, and
The dry lithographic plate according to claim 1, which comprises heating at ~210°C for 1 to 5 minutes and removing the image protection substance and the thin film of the non-adhesive substance applied thereon with a lower alcohol. plate-making method.