JPH0345824B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to photosensitive lithographic printing plates. Generally, a diazo resin obtained by condensation polymerizing a diazo compound with formaldehyde releases nitrogen through photolysis and loses its water solubility. Taking advantage of this property, it is widely used as a photosensitive material for making planographic plates for offset printing. In other words, when a water-soluble diazo resin is applied to a support (such as an aluminum plate) and exposed to light through a negative, the exposed areas become insoluble in water, and if this is developed with water,
A positive image is obtained on the surface of the support, which accepts fatty printing ink in the presence of fountain solution. Typical diazo resins include formaldehyde condensates of p-diazodiphenylamine. Therefore, there are plate-making materials in which only diazo resin is coated on the support, but as described in Japanese Patent Publication No. 1167-1167 and Japanese Patent Publication No. 30859-1985, diazo resin and organic coupling agent or inorganic coupling agent are added. A plate-making material is known in which a mixture of an organic salt of a diazo resin or an inorganic salt of a diazo resin soluble in an organic solvent is produced by reaction, and a mixture of this, an organic solvent-soluble resin, and a dye is coated on a support. Diazo resins, diazo resin organic salts, or diazo resin inorganic salts are relatively stable in a solid state, but when applied in a solution state or on a support,
Due to a dark reaction, it deteriorates within a few days,
Unexposed areas may not be easily developed, and non-image areas may become smudged. In order to overcome these shortcomings in storage stability, attempts have been made to add phosphoric acid, citric acid, tartaric acid, etc. into the photosensitive layer, but no significant effect could be expected in either case. The present invention solves the above-mentioned drawbacks and provides a photosensitive composition that does not stain unexposed areas even after several months or even after several days under harsh conditions. is a photosensitive layer consisting of a diazo resin organic salt or diazo resin inorganic salt and an organic solvent-soluble polymer compound, and the following general formula (): [In the formula, R is hydrogen or a methoxy group, and Z
are sulfonates, carboxylates, and potassium thiocyanates. ] An organic solvent-soluble diazo compound salt represented by
The photosensitive lithographic printing plate is characterized in that the content is 0.1 to 50% by weight based on the total weight of the photosensitive layer. The diazo resin organic salt or diazo resin inorganic salt used in the present invention is
-1167, Japanese Patent Publication No. 53-24449, and Japanese Patent Publication No. 54-98613, a condensate of p-diazodiphenylamine, 3-methoxydiphenylamine or a derivative thereof, and formaldehyde or acetaldehyde, Acidic aromatic compounds (e.g. phosphinic, phosphonic, sulfonic and carboxylic acid compounds of benzene, toluene and naphthalene and their derivatives) or hydroxyl containing aromatic compounds (e.g. 2-hydroxy-4-methoxybenzophenone, 2,2'-dihydroxy-
4,4'-dimethoxybenzophenone, 2-hydroxy-4-methoxy-benzophenone-5-sulfonic acid, 2-hydroxy-4-methoxy-benzophenone-5-sulfonic acid trihydrate), or inorganic compounds (e.g. , hexafluoric acid, hydroborofluoric acid, borofluoric acid, hydrosilicic acid, borosilicate, potassium thiocyanate, sodium thiocyanate) to make it insoluble in water and soluble in organic solvents. It is something. Examples of the organic solvent-soluble polymer compounds used in the present invention include epoxy resins, polybutyral resins, styrene-maleic anhydride copolymer resins, Sierrak resins, multi-component acrylic resins, and derivatives thereof, particularly those described in US Pat. No. 4,282,301. The acrylic resins described in . Moreover, the above-mentioned polymer compounds can be used alone or in combination of two or more. Furthermore, a plasticizer or a dye can be added to the photosensitive layer, if necessary. Dyes are added to make it possible to clearly distinguish between the support and the image area after development.Dye may cause color loss in the image area due to development, or may cause diazo photosensitive materials or organic polymer compounds to fade. I don't like things that react. Therefore, suitable dyes include, for example, Oil Blue #603 (Orient Chemical Industry Co., Ltd.).
), Victoria Blue-BOH (Hodogaya Chemical Industry Co., Ltd.)
), crystal violet, crystal blue, methylene blue, malachite green, etc. can be used. The organic solvent-soluble diazonium compound salts represented by the general formula () used in the present invention include p-diazodiphenylamine, 3-methoxy-diazodiphenylamine or derivatives thereof, the above-mentioned acidic aromatic compounds, and hydroxyl group-containing compounds. It is possible to use compounds that are made insoluble in water and soluble in organic solvents by reacting with aromatic image compounds or inorganic compounds. Specific examples include p-toluenesulfonate of p-diazodiphenylamine, benzoate of p-diazodiphenylamine, and 2-hydroxy-4-methoxybenzophenone-5 of p-diazodiphenylamine. -sulfonate, p-diazodiphenylamine dodecylbenzenesulfonate, p-diazodiphenylamine potassium thiocyanate, 3-methoxydiazodiphenylamine p-toluenesulfonate, 3-methoxydiazodif Examples include 2-hydroxy-4-methoxybenzophenone-5-sulfonate of enylamine and dodecylbenzenesulfonate of 3-methoxydiazodiphenylamine. 0.1 to 50% of these to the above photosensitive composition.
Add % by weight, preferably 1.0-15% by weight. If it is less than 0.1% by weight, it will have no effect on storage stability under harsh conditions (high temperature, high humidity), and if it is added more than 50%, the sensitivity will drop too much, resulting in insufficient exposure or poor adhesion. This is undesirable as it can cause As a support to which the photosensitive composition of the present invention is applied, paper, plastic film, zinc, copper, aluminum, stainless steel, or a composite material combining two or more of these can be used, and the surface is anodized. An aluminum plate made of aluminum can also be suitably used. The above photosensitivity can be improved by using an organic solvent such as methyl cellosolve, ethyl cellosolve, dimethyl formamide, dimethyl sulfoxide, methanol, methylene chloride, methyl cellosolve acetate, ethyl cellosolve acetate, etc. alone or a mixture of two or more thereof. The composition is dissolved, and the solution is applied to a support and dried. For development, inorganic or organic alkalis, e.g.
An aqueous solution of sodium silicate, potassium silicate, caustic soda, potassium hydroxide, monoethanolamine, diethanolamine, triethanolamine, etc. can be used as the developer, and it is also preferable to further contain an anionic surfactant and an organic solvent. The present invention will be explained in detail by the following examples. Example 1 Under a nitrogen stream, 0.3 g of azobisisobutyronitrile was added to 150 g of dioxane and heated to 80-85°C, into which were added 50 g of 2-hydroxy-3-phenoxypropyl acrylate and 25 g of methyl methacrylate. , acrylonitrile 10g, methacrylic acid 2
g of a mixed solution was added dropwise. After the addition was completed, stirring was continued for 3 hours, and 150 g of dioxane was added, followed by pouring into water to precipitate the copolymer. The precipitate was filtered and dried at 40°C to obtain Copolymer 1. Next, a 1S (class 1 special grade) aluminum plate with a thickness of 0.25 mm was immersed in a caustic soda solution at 70°C for 10 seconds to degrease it, grained with a nylon brush, washed with water, and heated to 20°C at 70°C. % sodium phosphate solution,
Etched for 10 seconds and washed with water. After washing with water: Anodize in a 10% sulfuric acid solution at a current density of 2A/dm ² for 2 minutes, wash with water, and then treat with a 5% sodium silicate solution at 70°C for 30 seconds to form the anodized aluminum plate (1). Created. Add the following photosensitive liquid to this aluminum plate (1).
(A) and (B) were applied and dried.

[Table] Note: Photosensitive liquid (A) is a control example. Aluminum plate coated with the above photosensitive liquids (A) and (B) (1)
were designated as printing plates (A)-1 and (B)-1, respectively. print version
Negative film and Kodakku Scale Tablet No. 2 (product name) were vacuum-adhered to (A)-1 and (B)-1, respectively, and a 1 m
Exposure was made for 45 seconds at a distance of . Next, it was immersed in a developer having the composition shown below at 25° C. for 1 minute, and then washed with water. Sodium silicate 40% aqueous solution 50g Sodium isopropylnaphthalene sulfonate 5g Potassium sulfite 2g Phenyl glycol 40g Water 903g The sensitivity of printing plate (A)-1 is 10 steps solid, printing plate (B)-
The sensitivity of 1 was solid at 6 steps. In (A)-1, the halftone dots in the highlight areas are a bit thick and the shadow areas are a bit clogged. On the other hand, (B)-1 is a highlight,
All shadow areas faithfully reproduce film halftone dots. (A)-1 fogs in about 2 minutes under indoor fluorescent light (i.e., the sensitivity is too high), and (B)-1 produces fog after about 10 minutes.
No fogging occurs even if left for minutes. Therefore, when using (B)-1, tasks such as imposition became easier. In addition, (A)-1 and (B)-1 were left unexposed and undeveloped in a constant temperature and humidity chamber at 45°C and 75% humidity for one week, and then plate-made using the above method, and the image was created. However, when printing, in (A)-1,
(B)
-1 was able to obtain good printed matter without stains. Example 2 Aluminum plate with a thickness of 0.25 mm and a width of 1000 mm (material
1100) was degreased with alkaline, washed with water, and then polished with a brush using an abrasive consisting of a 20% aqueous solution of carborundum. Next, remove the polishing residue thoroughly with a 10% caustic soda bath, wash with water, and then add 2.5% hydrochloric acid,
In an electrolytic solution (20℃) containing 0.1% sodium chloride,
AC electrolytic polishing was performed at a current density of 10 A/dm ² for 10 seconds. After that, it was washed with water and placed in a 10% sulfuric acid bath (30℃).
Anodization was carried out for 60 seconds at a current density of 2 A/dm ² . After washing with water, AC anodic oxidation treatment was performed in a 5% potassium silicate bath (40°C) at a current density of 2 A/dm ² for 15 seconds, followed by washing with water and drying to obtain an anodized aluminum plate 2. The following photosensitive solutions (C) and (D) were applied to this aluminum plate 2 and dried.

[Table] Note: Photosensitive liquid (C) is a control example. Aluminum plate 2 coated with photosensitive liquids (C) and (D) was
They were designated as printing plates (C)-2 and (D)-2, respectively. Negative film and Kodak Scale Tablet No. 2 (trade name) were vacuum-adhered to printing plates (C)-2 and (D)-2, and exposed in the same manner as in Example 1. Compared to printing plate (C)-2, exposed printing plate (D)-2 shows a clear latent image due to photobleaching, and the boundary between exposed and unexposed areas can be marked and identified. did it. Next, development was carried out in the same manner as in Example 1.
The sensitivity of (C)-2 was 10 steps solid, and the sensitivity of (D)-2 was 6 steps solid. In (C)-2, the halftone dots are a bit thick like in (A)-1, but in (D)-2, the film halftone dots are faithfully reproduced. In addition, (C)-2, (A)- were placed in the same temperature and humidity chamber as in Example 1.
(C)-2 caused stains in the non-image area after about 3 days, but (D)-2 produced good prints with no stains even after a week had passed. was completed. Example 3 In place of copolymer (1) in Example 1, a copolymer (2) having the following weight ratio composition was produced in the same manner as in Example 1. 2-Hydroxy-3-phenoxypropyl acrylate 20 2-hydroxyethyl methacrylate 40 Methyl methacrylate 35 Methacrylic acid 5 Using this copolymer (2), the following photosensitive solutions (E) and (F) were prepared and carried out. The same anodized aluminum plate (1) used in Example 1 was coated and dried.

[Table] Note: Photosensitive solution (E) is a control example. Aluminum plates (1) coated with photosensitive solutions (E) and (F), respectively, were used as printing plates (E)-1 and (F)-1. Next, exposure, development, and water washing were performed in the same manner as in Example 1. (E)-1 has halftone dots that are a bit thick like (A)-1, but (F)-1 faithfully reproduces the film halftone dots. In addition, when (E)-1 and (F)-1 were placed in the same temperature and humidity chamber as in Example 1, (E)-
1 developed stains in the non-printing area after about 3 days, but (F)-
No. 1 was able to obtain good printed matter with no stains even after one round. From the above examples, it is clear that the printing plate having the photosensitive layer of the present invention has good printing characteristics. Comparative Example As a control example, the following photosensitive liquid (H) was applied to the anodized aluminum plate 1 produced in Example 1,
Dry. Composition Photosensitive liquid (H) (g) Methyl cellosolve 65 Copolymer (1) 15 2-hydroxy-4-methoxybenzophenone-5-sulfonate of p-diazo-2,5-sibutoxyphenylmorpholine 0.5 Victoria Blue - BOH 0.4 The aluminum plate coated with the above photosensitive liquid (H) is (H) -
1 was left in a constant temperature and humidity chamber at 45°C and 75% humidity for one week as in Example 1, and then exposed, developed and printed in the same manner as in Example 1. The print area was smeared and could not be printed. As is clear from the comparison between Example 1 and Comparative Example,
Example 1 using the organic solvent-soluble diazo compound salt represented by the general formula () has excellent storage stability.

Claims (1)

[Scope of Claims] 1. A photosensitive layer consisting of a diazo resin organic salt or a diazo resin organic salt and an organic solvent-soluble polymer compound has the following general formula (): [In the formula, R is hydrogen or a methoxy group, and Z
are sulfonates, carboxylates, and potassium thiocyanates. ] An organic solvent-soluble diazo compound salt represented by
A photosensitive lithographic printing plate characterized in that the content is 0.1 to 50% by weight based on the total weight of the photosensitive layer.