JPH057704B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a photosensitive composition, more specifically,
In particular, it relates to a photosensitive composition suitably used for planographic printing plates.

(Prior Art) Conventionally, known diazo compounds, such as diazo resins, which are formaldehyde condensates of p-diazodiphenylamine, have been typically used as photosensitive compositions for lithographic printing plates. . When a photosensitive layer obtained by coating such a diazo compound on a support whose surface has been previously subjected to a hydrophilic treatment is exposed to light through a negative film, the diazo compound in the exposed portion decomposes and becomes insoluble.
On the other hand, the unexposed areas remain soluble in aqueous solutions. Therefore, by subjecting this material to a development treatment using an alkaline aqueous solution or the like, the unexposed portions are dissolved and removed, and an image made of the photodecomposed diazo compound can be formed on the support. The image made of the insolubilized diazo compound in the exposed area exhibits lipophilicity and is ink receptive.
On the other hand, in the unexposed areas, since the surface of the hydrophilic support is exposed, it is water-receptive and repels ink, so that it can be used as a lithographic printing plate.

By the way, images formed only with such insolubilized diazo compounds have low strength and abrasion resistance;
Printing durability is poor. Therefore, for the purpose of reinforcing the image, a method is used in which a lacquer is fixed on the image after exposure and development, or a reinforcing resin is mixed in advance with the diazo compound. Since the former method involves many steps, the latter method is now generally used.

The reinforcing resin to be mixed with the above diazo compound is
The required characteristics are that the photosensitive layer formed with the diazo compound is soluble before exposure and becomes insoluble upon exposure to form a lipophilic image, and development is usually performed using an aqueous solution. Therefore, it is also required to have the property of dissolving and swelling in an aqueous solution to some extent, and the property of becoming lipophilic after becoming insoluble together with the diazo compound.

Various types of reinforcing resins have been proposed so far, but none that fully satisfy the above-mentioned characteristics have yet been obtained.

In view of these circumstances, the present inventors have conducted intensive research and have found a reinforcing material that has the above characteristics, has good compatibility with diazo compounds, and has excellent stability over time. They discovered a resin and completed the present invention.

(Means for solving the problem) That is, the present invention solves the general formula or (R in the formula is a hydrogen atom or a methyl group) A photosensitive composition comprising a polymer containing 10 to 50% by weight of the structural unit represented by the formula and a diazo compound as photosensitive components. be.

The polymer used in the composition of the present invention contains a structural unit represented by the above general formula () or (), and is a polymer of glycerin monoacrylate or glycerin monomethacrylate, or a polymer of these and other addition polymers. It is a copolymer with a sexually unsaturated compound. This copolymer contains glycerin monoacrylate units, glycerin monomethacrylate units, or both units.
Those containing 10 to 50% by weight are used. Other addition polymerizable unsaturated compounds used in such copolymers include, for example, acrylonitrile, methacrylonitrile, acrylic acid, methacrylic acid, methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, acrylic Preferred examples include butyl acid and butyl methacrylate. In addition, examples of addition polymerizable unsaturated compounds other than those mentioned above include various known acrylic esters, methacrylic esters, acrylamides and methacrylamides, styrenes, vinyl ethers, vinyl acetate, maleic acid, and N-vinylpyrrolidone. , and various other vinyl compounds are also preferably used.

The polymer used in the present invention can be produced by solution polymerization, emulsion polymerization, suspension polymerization, etc. according to conventional methods. In this polymerization reaction, conventional polymerization initiators such as peroxides and azo compounds, redox polymerization initiators, and the like may be used.

If this polymer contains 10 to 50% by weight of the structural unit represented by the above general formula () or (), the object of the present invention can be achieved, but the physical properties of the formed image can be strengthened and the sensitivity can be improved. In order to improve oiliness, copolymers obtained using acrylonitrile or methacrylonitrile as described above are useful as copolymerization components, and aqueous alkaline solutions are often used as developing solutions, and acrylic acid is used as a copolymerization component. Copolymers obtained using unsaturated carboxylic acids such as methacrylic acid and the like are also preferred in terms of improving developability.

By the way, glycerin monoacrylate or glycerin monomethacrylate used in the polymer of the present invention often contains diesters and triesters as impurities, and may cross-link and gel during polymer synthesis. The method is to first create a polymer of unsaturated carboxylic acids such as acrylic acid or methacrylic acid, or a copolymer of these and other addition-polymerizable unsaturated compounds, then add glycidol and perform the following reaction. A method for obtaining the desired polymer is effective.

or In this case, amines can be used as catalysts.

The polymer used in the present invention has a structural unit represented by the general formula () or () that has a balance between solubility in an aqueous solution for good developability and lipophilicity of an insoluble image formed by exposure. From this point of view, the content is preferably in the range of 10 to 60% by weight, and the various addition polymerizable unsaturated compounds described above are used as the copolymerization component.

The diazo compound in the composition of the present invention includes:
Well-known photosensitive diazo compounds can be used. Preferred diazo compounds include salts of condensates of p-diazodiphenylamine and formaldehyde, such as phenol salts, fluorocapric acid salts, and salts with aromatic sulfonic acids, which contain two or more diazo groups in the molecule. Examples include diazo compounds. Preferred aromatic sulfonic acids used here include, for example, 2-hydroxy-4-methoxy-benzophenone-5-sulfonic acid, p-toluenesulfonic acid, 1-naphthol-5-sulfonic acid, triisopropylnaphthalenesulfonic acid,
4,4'-biphenyldisulfonic acid, 5-nitro-
Examples include o-toluenesulfonic acid, 2,5-dimethylbenzenesulfonic acid, 2-nitrobenzenesulfonic acid, 3-chlorobenzenesulfonic acid, and 3-bromobenzenesulfonic acid. In addition to the above-mentioned diazo compounds, for example, a condensate of 2,5-dimethoxy-4-p-tolylmercaptobenzenediazonium and formaldehyde, 2,5-
Condensate of dimethoxy-4-morpholinobenzenediazonium and formaldehyde, 2,6-bis(4-diazo-2,5-dimethoxyphenylamino)-4-N,N-(di-p-hydroxyethyl)
Aromatic sulfonates such as amino-1,3,5-triazine can also be used.

The content of the diazo compound in the composition of the present invention is selected in the range of 1 to 40% by weight, preferably 5 to 20% by weight based on the polymer used as the reinforcing resin.

The composition of the present invention may contain dyes, pigments,
Stabilizers, plasticizers, fillers, etc. can also be added. In particular, it is useful to add a dye to make the image formed after exposure and development easier to see.

To explain one example of using the composition of the present invention for a lithographic printing plate, first, a polymer as a reinforcing resin, a diazo compound, and if desired, additives such as a dye and a stabilizer are dissolved in a suitable solvent. The resulting photosensitive solution is applied onto a support having a hydrophilic surface and dried. As the coating method, a commonly used method such as a sheet coating method or a web coating method using a spin coater, curtain coater, roll coater, spray coater, etc. can be used. Application amount is 0.1 to 5g/ in terms of solid content.
A range of m ² is preferred. The above-mentioned solvent is preferably a mixed solvent such as methyl cellosolve-methanol, methyl cellosolve-methanol-dichloroethane, etc., if selected from those that dissolve both the polymer and the diazo compound.

In addition, the support may be one that has been conventionally used as a lithographic printing plate material, such as an aluminum plate,
Metal plates such as zinc plates and steel plates, plastic sheets such as polyethylene terephthalate, polyamide, polypropylene, and polycarbonate, paper, and their laminates or those that have been subjected to plating, electrolytic treatment, or other chemical treatments are used. It will be done. These treatments are carried out in order to prevent mutual adverse effects between the support surface and the diazo compound, as well as to increase hydrophilicity and improve adhesion to the image. It is particularly effective to grain the aluminum plate and then anodize it in phosphoric acid, sulfuric acid or oxalic acid.

Next, when the lithographic printing plate material with the photosensitive layer formed in this way is exposed to light through a negative film, the exposed areas become insoluble, while the unexposed areas remain soluble, so a developer such as water or an alkaline aqueous solution is used. By developing it using a lithographic printing plate, the unexposed portions are dissolved and removed, an image is formed on the support, and a lithographic printing plate can be obtained. As a developer,
Alkali such as sodium hydroxide, potassium hydroxide, sodium silicate, potassium silicate, sodium phosphate, potassium phosphate, ammonium phosphate, sodium carbonate, ammonia, triethanolamine, surfactants, alcohols,
For example, an aqueous solution containing isopropyl alcohol, ethyl alcohol, benzyl alcohol, diacetone alcohol, etc. is used.

The photosensitive layer obtained from the photosensitive composition of the present invention is
It is characterized by good developability and the resulting images have high strength and abrasion resistance. These characteristics are due to the above general formula () in the polymer used as reinforcing resin.
Or, it is the effect of the structural unit shown in parentheses, and its mechanism of action is not necessarily clear, but
It seems that two adjacent hydroxyl groups are involved.

In addition, the polymer used as the reinforcing resin in the present invention has the characteristic that it can be developed with water or similar materials, and has good oil sensitivity, whereas all conventionally known reinforcing resins can only be developed with something other than water. have.

EXAMPLES Next, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited to these Examples in any way.

Example 1 Methyl methacrylate 65g, acrylonitrile 65g
g, 70 g of acrylic acid, and 1.0 g of azobisisobutyronitrile were dissolved in 380 g of 2-methoxyethanol, and the reaction was continued at 100° C. for 6 hours while passing nitrogen through the solution. After cooling the reaction mixture to 60° C., 20 g of 2-methoxyethanol, 0.6 g of hydroquinone as a polymerization inhibitor, and 5 g of a 40% by weight methanol solution of trimethylbenzylammonium hydroxide as a reaction catalyst were added.
Next, after raising the temperature of the contents to 80°C, 60 g of glycidol containing 0.6 g of hydroquinone was added dropwise over 1 hour, and immediately after the dropwise addition, 5 g of a 40% by weight methanol solution of trimethylbenzylammonium hydroxide was added, and the mixture remained for 5 hours. continued to react.
Then, after cooling to room temperature, a pale yellow viscous polymer solution
I got (1). The glycidol addition reaction rate (to carboxyl groups) of the obtained polymer was 61%.

Next, using this acrylic copolymer solution (1),
A photosensitive composition shown below was prepared.

Photosensitive composition copolymer solution (1) 5.5g 2-methoxy-4-hydroxy-5-benzoylbenzenesulfonic acid salt of p-diazophenylamine and paraformaldehyde condensate 0.25g Oil Blue #603 (Orient Chemical) Kogyo Co., Ltd.
0.075 g 2-methoxyethanol 10.5 g Methanol 13.8 g Ethylene dichloride 13.8 g This photosensitive composition was coated using a whiler on an aluminum plate that had been mechanically polished and anodized with sulfuric acid, and then heated at 100°C for 2 minutes. It was dried to obtain a photosensitive printing plate. The coating amount after drying was 1.5 g/m ² .
A negative film was vacuum-adhered onto the photosensitive layer of the obtained photosensitive printing plate, exposed to light for 1 minute at a distance of 1 m using a 3KW metal halide lamp (manufactured by Eye Graphics Co., Ltd.), and then heated to room temperature using a developer with the following composition. The unexposed areas were removed by processing for 1 minute to form an image.

Developer: Benzyl alcohol 3g Sodium silicate 40% by weight aqueous solution 1g Sodium dodecylbenzenesulfonate 1g Water 995g
When I printed 700 CDs on high-quality paper, I was able to print over 50,000 copies.

Example 2 200 g of 2-methoxyethanol was placed as a reaction solvent in a 1-volume 4-necked flask equipped with a stirrer, a reflux condenser, a dropping funnel, and a thermometer.
It was heated to 100°C while purging with nitrogen. In the dropping funnel, add 50 g of glycerol monomethacrylate, 70 g of methyl methacrylate, 70 g of acrylonitrile,
A mixture of 10 g of methacrylic acid and 0.8 g of benzoyl peroxide as a polymerization catalyst was added dropwise over 2 hours, and 15 minutes after the dropwise addition was completed, 200 g of 2-methoxyethanol and 0.2 g of benzoyl peroxide were added. The reaction was completed by heating for 4 hours. After cooling to room temperature, a pale yellow viscous polymer solution (2) was obtained.

Next, the photosensitive composition shown below was prepared using this acrylic copolymer solution (2).

Photosensitive composition Copolymer solution (2) 6.4g Diazo resin in Example 1 0.25g Oil Blue #603 0.075g 2-methoxyethanol 9.6g Methanol 13.8g Ethylene dichloride 13.8g This photosensitive composition was prepared in Example 1. It was applied to the anodized aluminum plate used in . The coating amount after drying was 1.5 g/m ² . The photosensitive printing plate thus obtained was exposed in the same manner as in Example 1,
After developing it, I put it on a printing press and was able to print over 50,000 copies.

Claims (1)

[Claims] 1. General formula or A photosensitive composition comprising a polymer containing 10 to 50% by weight of a structural unit represented by the formula (R in the formula is a hydrogen atom or a methyl group) and a diazo compound as photosensitive components.