JPS6142251B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention relates to a lithographic printing plate having a support coated with a novel photosensitive composition. A photosensitive plate obtained by coating a thin film of a photosensitive substance on a support is exposed to light through a transparent original image to create a difference in solubility between exposed and unexposed areas, and developed with an appropriate solvent to form a layer on the photosensitive plate. Various techniques for forming relief images have been proposed. The relief images obtained are used in the production of printing plates such as offset plates, letterpress plates, and gravure plates, printed wiring boards, and metal processing. [Prior Art] Photosensitive substances conventionally used in the production of these materials include (1) mixtures of polyvinyl alcohol and dichromate, (2) mixtures of orthoquinone diazide derivatives and phenol nopolac or metacresol. , (3) α,β unsaturated ketones, and (4) combinations of aromatic diazide compounds and various polymer compounds. Each of these photosensitive materials has problems in terms of adhesion to a support, storage stability, chemical resistance, printing durability, and the like. In addition, in photosensitive materials for planographic printing plates,
Diazonium compounds are known. In particular, polymeric diazonium salts (hereinafter referred to as diazo resins) having several diazonium groups in their molecules have been widely used because they become insolubilized and lipophilic by the action of light. That is, when diazo resin is applied to a support such as hydrophilic paper, plastic, or aluminum plate, and this is exposed to active light through a transparent original, the exposed areas become insoluble, and the unexposed areas are treated with an appropriate solvent. Removal exposes the hydrophilic support. When this is printed using an offset printing machine, the unexposed areas receive water and repel ink, while the exposed areas repel water and receive ink, thereby allowing printing. Examples of the diazo resin include p-aminodiphenylamine, p-phenylenediamine, p-
- Obtained by diazotizing ethylaminoaniline etc. Water-soluble diazo resins have been used in which aromatic diazonium salts are condensed with active carbonyl-containing compounds, especially aldehydes such as formaldehyde, in an acidic medium. Methods for producing the resin are described in U.S. Pat. When the resin is used in a lithographic printing plate, the resin is used alone (see U.S. Pat. No. 2,667,415, Japanese Patent Publication No. 17602/1983), and a mixture of the resin and a hydrophilic colloid is used. (U.S. Patent No. 2100063, U.S. Patent No. 2687958 and U.S. Pat. No. 2687958)
2900281) is known. However, in the former case, the abrasion resistance of the obtained relief image is low and printing durability is poor. In addition, in the latter case, since it is a mixture of water-soluble diazo resin and water-soluble resin, it inherently has low oil sensitivity and ink receptivity, and also has the disadvantage of poor storage stability due to dark reaction. ing. It is also known to use mixtures of water-soluble diazo resins and water-insoluble, lipophilic resins.
(See US Pat. No. 2,826,501 and US Pat. No. 3,295,974.) However, in this case, it is difficult to select a solvent during coating, and there are also problems with storage stability, printing durability, etc. The reason for the poor storage stability as described above is that the diazo resin is used in the form of a double salt with zinc chloride, a phosphate, or other acid salts, which are water-soluble and unstable against moisture. This is thought to be caused by this. Furthermore, in order to improve storage stability, a water-soluble diazo resin is reacted with some phenolic coupling component to obtain an addition product that is almost insoluble in water and soluble in organic solvents. It has also been proposed to use oleophilic film-forming resins alone or in conjunction with lipophilic film-forming resins. (See Japanese Patent Publication No. 47-1167 and U.S. Patent No. 3,300,309.) However, since the addition products contain relatively weak bonds due to the properties of salts or complex salts, they are easily reproducible in, for example, organic solvents. There are problems in that it is easily decomposed and its stability is not satisfactory. The present invention has been made to solve these problems. An object of the present invention is to provide a photosensitive resin composition that has excellent chemical resistance, printing durability, and ink receptivity. [Structure of the Invention] A water-insoluble organic solvent-soluble reaction product of a condensation product of a diazo compound and a carbonyl-containing organic compound and a halogenated Lewis acid or a perhalogen salt is used as the diazo resin, and the diazo The above object is achieved by using a photosensitive composition comprising a resin and a specific lipophilic film-forming resin described below which is soluble in organic solvents and substantially insoluble in water. Here, soluble in organic solvent means that both the diazo resin and the lipophilic film-forming resin are soluble in common organic solvents such as methanol, acetone, ethyl cellosolve, etc. at room temperature. The diazo resin used in the present invention (hereinafter referred to as the diazo resin of the present invention) is a condensation product of an aromatic diazonium salt and formaldehyde, acetaldehyde, etc., such as BF ₄ ^- , PF ₆ ^- ,
These are Lewis halide salts having an anion component such as SiF ₆ ^-- , SbF ₆ ^-- or BeF ₄ ^-- , and perhalogen salts having an anion component such as IO ₄ ^-- . A particularly preferred diazo resin of the present invention is a condensate of p-diazodiphenylamine and formaldehyde.
It is a salt with anionic components of PF ₆ ^- and BF ₄ ^- . The diazo resin of the present invention is almost insoluble in water and soluble in organic solvents, and has strong salt bonds, so it has excellent stability. The organic solvent-soluble, almost water-insoluble lipophilic film-forming resin used in the photosensitive composition used in the present invention includes 2-hydroxyethyl methacrylate-methyl methacrylate copolymer;
2-hydroxyethyl methacrylate-methyl methacrylate-butyl acrylate copolymer, 2
- One or more resins selected from -hydroxyethyl methacrylate-methyl methacrylate-butyl acrylate-methacrylic acid copolymer and 2-hydroxyethyl methacrylate-methyl methacrylate-acrylonitrile-methacrylic acid copolymer. Here, "almost insoluble in water" means that both the diazo resin and the lipophilic film-forming synthetic resin have a solubility in water of about 1 at room temperature.
% or less. These resins have good compatibility with the diazo resin of the present invention, can be easily applied to a support and have the ability to form a uniform film, have good lipophilicity and good ink receptivity, and are suitable for printing. It has the characteristics of being resistant to chemicals used in plate manufacturing, having flexibility and abrasion resistance, and good storage stability.
Excellent printing durability. The content of the diazo resin of the present invention in the photosensitive composition used in the present invention is 1 to 30% by weight, preferably 3 to 15% by weight. Various additives can be added to the photosensitive composition used in the present invention. For example, alkyl ethers (e.g., ethyl cellulose, methyl cellulose) to improve coating properties, plasticizers to impart flexibility and abrasion resistance to the coating film (e.g., butylphthalyl, polyethylene glycol, diethyl citrate, tributyl phthalate), etc. , dibutyl phthalate, dihexyl phthalate, dioctyl phthalate, tricresyl phosphate, tributyl phosphate, trioctyl phosphate, tetrahydrofurfuryl oleate, oligomers of acrylic or methacrylic acid,) for visualizing images. As coloring substances, pigments such as acridine dyes, cyanine dyes, styryl dyes, triphenylmethane dyes and phthalocyanines, and photochromic substances (azide compounds, spiropyran compounds) for the purpose of visualizing images by exposure to light may be added. can. The amount of these additives added varies depending on the purpose for which they are used, but
Generally from 0.5 to 30% by weight based on total solids. The concentration of the photosensitive composition during coating is preferably in the range of 1 to 50% by weight, and the coating solvents used include methyl cellosolve, ethyl cellosolve, methyl cellosolve acetate, acetone,
Methyl ethyl ketone, methanol, dimethyl formamide, dimethyl sulfoxide or a mixed solvent thereof is suitable. However, in some cases, a mixed solvent of the above-mentioned solvent and another organic solvent may also be used. The photosensitive lithographic printing plate of the present invention is used in a conventional manner. That is, by exposing to light through a transparent original having line images, halftone dot images, etc., and then developing with an aqueous developer, a negative relief image is obtained with respect to the original. Light sources suitable for exposure include carbon arc lamps, mercury lamps, xenon lamps, metal halide lamps, strobes, and the like. Aqueous solutions used for development include aqueous solutions of sodium hydroxide, potassium hydroxide, sodium carbonate, sodium metasilicate, dibasic sodium phosphate, dibasic sodium phosphate, etc., and medium containing small amounts of surfactants and organic solvents. Acidic aqueous solutions such as hydrochloric acid, phosphoric acid, tartaric acid, citric acid, and acetic acid are used. Further, in an alkaline or acidic aqueous solution, a small amount of a surfactant or an organic solvent miscible with water may be added for the purpose of accelerating development and eliminating uneven development. The relief image thus obtained has high chemical resistance, withstands corrosive liquids such as nitric acid and ferric chloride solution, and is suitable as a lithographic printing plate. In addition, the relief image has strong oil sensitivity, mechanical strength, and adhesion to the support, making it excellent for use in planographic printing.Moreover, it has a long printing durability and has the excellent effect of being able to withstand printing on a large number of sheets. There is. As the support used in the photosensitive lithographic printing plate of the present invention, various supports can be used, as described above, but aluminum plates are particularly preferred. However, if the aluminum plate is used without treatment,
There are disadvantages in that the adhesion of the photosensitive composition is poor and the photosensitive composition decomposes. In order to eliminate this drawback, various proposals have been made in the past. For example, the surface of an aluminum plate is grained and then treated with silicate. (U.S. Patent No. 2714066
No.) Method of treatment with organic acid salts. (U.S. Patent No.
2714066) Method of treatment with phosphonic acids and their derivatives. (US Pat. No. 3,220,832) Method of treatment with potassium hexafluorozirconate. (US Pat. No. 2,946,683), a method of anodizing, and a method of treating with an aqueous solution of an alkali metal silicate after anodizing (US Pat. No. 3,181,461). The aluminum plate used as the support for the photosensitive lithographic printing plate of the present invention is preferably one whose surface has been grained, anodized, and then sealed. Methods for graining include degreasing the surface of the aluminum plate, then brush polishing,
There are ball polishing methods, chemical polishing methods, electrolytic etching methods, etc. For example, anodizing is performed by using an aluminum plate as an anode in an aqueous or non-aqueous solution of an inorganic salt such as phosphoric acid, chromic acid, boric acid, or sulfuric acid, or an organic acid such as oxalic acid or sulfamic acid, or a mixture of two or more of these acids. This is done by passing an electric current. Furthermore, the sealing treatment is carried out by immersion in a hot aqueous solution of a sodium silicate solution, hot water, and some inorganic or organic salts, or by using a steam bath. The photosensitive lithographic printing plate obtained by coating the photosensitive composition according to the present invention on the aluminum support treated in this way has good storage stability of the photosensitive layer and good adhesion to the support, and is easily exposed to light. It gives a clear relief image after development and can give printed matter with a clear image even in a very long printing process. [Example] Example 1 30 g of 2-hydroxyethyl methacrylate, 65 g of methyl methacrylate, 5 g of butyl acrylate
g, 0.4 g of azobisisobutyronitrile was dissolved in 300 ml of dioxane in a sealed tube purged with nitrogen gas.
The reaction was carried out at 65°C for 30 hours. After the reaction was completed, the reaction solution was poured into water 5 with stirring, and the resulting white precipitate was overdried to obtain Copolymer-1 (97.5 g). At room temperature, 5% diazo resin (Special Publication No. 39-17602)
Zinc chloride, a condensate of paradiazodiphenylamine and formaldehyde, described in the specification of No.
200 ml of an aqueous solution (sulfuric acid double salt) and 50 ml of a 10% ammonium hexafluorophosphate aqueous solution were mixed, and the resulting precipitate was immediately absorbed and filtered, followed by drying under reduced pressure at 30 to 40°C. 10 g of diazo resin-1 (hexafluorophosphate) which is almost insoluble in water and soluble in organic solvents such as methyl cellosolve and ethyl cellosolve was obtained. An aluminum plate is immersed in a 20% sodium phosphate aqueous solution to degrease it, electrolytically polished, anodized in sulfuric acid, and further treated with a sodium metasilicate aqueous solution to produce aluminum used as a support for lithographic printing plates. Plate-1 was produced. The following photosensitive liquid A was applied to this aluminum plate-1 using a rotary coater to obtain a photosensitive lithographic printing plate (A).

[Table] The photosensitive lithographic printing plate (A) obtained here was imagewise exposed for 30 seconds from a distance of 80 cm using a metal halide lamp Idolfin 2000 (manufactured by Iwasaki Electric Co., Ltd.), and then the following developer solution-1 was used. This was developed to obtain a lithographic printing plate (A). Benzyl alcohol 30g Alkanol , exposure and development to obtain lithographic printing plates (B), (C), and (D), respectively.

[Table] Methyl cellosolve However, photosensitive lithographic printing plates (B) and (C) were developed with water, and (D) was developed with developer-1. Storage stability of the thus obtained photosensitive lithographic printing plates (A), (B), (C), and (D) and printing durability of the lithographic printing plates (A), (B), (C), and (D) When examining the properties, the results shown in Table 1 were obtained.

[Table] However, the storage stability in the table indicates the number of days that performance such as sensitivity and resolution changes when stored in an atmosphere of 40°C and 80% humidity compared to the one immediately after production of the photosensitive lithographic printing plate. Printability was determined by printing on high-quality paper using a sheet-fed offset printing machine Hamadastar CDX900 (manufactured by Hamada Seisakusho). As a result, it was confirmed that the photosensitive lithographic printing plate according to the present invention has excellent storage stability and high printing durability. Example 2 Copolymer-2 was synthesized in the same manner as in Example 1. The composition of copolymer-2 is 2-hydroxyethyl methacrylate: methyl methacrylate: butyl acrylate: methacrylic acid = 25:65:5:5
(molar ratio). In the photosensitive liquid A prepared in Example 1, copolymer-2 was used instead of copolymer-1.
Aluminum plate-1, which was used in Example 1 with photosensitive liquid B replaced with , was subjected to mechanical polishing, and aluminum plate-2, which was treated with an aqueous sodium metasilicate solution, was subjected to mechanical polishing. , Aluminum plate-3 treated with polyvinylphosphonic acid aqueous solution, Aluminum plate-4 treated with potassium hexafluorozirconate solution after mechanical polishing, and Aluminum plate anodized after mechanical polishing. -5 was coated using a spin coater.
The photosensitive printing plate thus obtained was exposed to light in the same manner as in Example 1, and developed with the following developer. Sodium metasilicate 50g Alkanol Indicated. In addition, when the photosensitive liquid D used in Example 1 was applied to aluminum plates-1, 2, 3, 4, and 5 and processed and printed in the same manner as above, the lithographic printing plate using aluminum plate-1 was obtained. Although it showed higher printing durability than other aluminum plates, the difference was slight.
Therefore, a photosensitive lithographic printing plate obtained by applying the photosensitive composition according to the present invention to an aluminum plate that has been grained and anodized and then sealed with an aqueous sodium silicate solution has an extremely high printing durability. It was confirmed that the effect of providing a lithographic printing plate with high strength and improving printing durability was maximum. Example 3 Copolymer 3 (composition molar ratio: 2-hydroxyethyl methacrylate: methyl methacrylate: acrylonitrile: methacrylic acid = 30:20:40:10) was synthesized in the same manner as in Example 1. In the photosensitive liquid A prepared in Example 1, copolymer-3 was substituted for copolymer-1, and resin shrimp coat as described in Dutch Patent Publication No. 7410806 was used.
1031 (manufactured by Schiel), Epicote-1001 (manufactured by Schiel), polyvinyl formal, and the resins Epicote-1006 (manufactured by Schiel) and Lumitol as described in German Patent Publication No. 2624074.
1:1 (weight ratio) mixture of AM80 (manufactured by BASF), Epicote 1002, Epicote 1004 and
A photosensitive liquid substituted with a 1:1:1 (weight ratio) mixture of acryloid AT-70 (manufactured by Rohm and Hass) was applied to the aluminum plate-1 used in Example 1 using a spin coater, and six types of A photosensitive lithographic printing plate was obtained. These printing plates were treated in the same manner as in Example 2 except that a developer having the composition shown below was used to obtain lithographic printing plates (Comparisons 18, 20, 21, and 22, respectively). Each of the obtained lithographic printing plates was applied to a printing machine and printed on high-quality paper. The results are shown in Table 2. As a result, it was confirmed that the resin used in the present invention exhibits higher printing durability compared to other resins. Developer composition Dodecyl sulfate 20g Methanol 90g Benzyl alcohol 60g Sodium alginate 5g Isobutyl alcohol 20g Monoethanolamine 1g Water 800g

[Table] Example 4 39g of 2-hydroxyethyl methacrylate, 70g of methyl methacrylate, 0.5g of benzoyl peroxide
g was dissolved in 200 ml of dioxane purified by distillation, and reacted at 110° C. for 6 hours in a nitrogen stream. After the reaction was completed, the reaction solution was diluted with acetone, poured into water, and the resulting white precipitate was taken and dried to obtain copolymer-4.
Obtained 103g. 200 ml of the same diazo resin (zinc chloride/sulfuric acid double salt) aqueous solution used in Example 1 at 5% and 10% at room temperature
50 ml of an aqueous ammonium perchlorate solution was mixed therein, and the resulting precipitate was filtered under suction and dried under reduced pressure at 30 to 40°C. Methyl cellosolve, almost insoluble in water,
10 g of diazo resin-2 (perchlorate salt) soluble in organic solvents such as ethyl cellosolve and dimethylformamide was obtained. The following photosensitive liquid was applied to the aluminum plate-1 used in Example 1 using a spin coater to obtain a photosensitive lithographic printing plate. Copolymer-4 5.0g Diazo resin-2 0.5g Cererose ethyl ether 0.2g Tricle difluoride 0.5g Victoria Blue Base F4R (manufactured by Vadeitsch Aniline Sodafabrik) 0.1g Methyl cellosolve 95ml Dimethyl formamide 5ml This photosensitive material The lithographic printing plate was exposed to light in the same manner as in Example 2, and the obtained lithographic printing plate was printed on an offset printing machine, and many printed matter with good images were obtained. Example 5 Copolymers-5 to 14 were synthesized in the same manner as in Example 1. Their compositions (molar ratios) are as follows. Copolymer 5: Ethyl methacrylate-methyl methacrylate-butyl acrylate = 30:65:
5 〃 6: Styrene-methyl methacrylate-
Butyl acrylate - methacrylic acid = 30:
50:15:5 〃 7: Propyl methacrylate - butyl acrylate - methacrylic acid = 50:45:5 〃 8: Methyl acrylate - acrylonitrile - methacrylic acid = 55:40:5 〃 9: Methyl methacrylate - butyl methacrylate - acrylic acid = 60:35:5 〃 10: Styrene - ethyl acrylate - methacrylic acid = 35:59:6 〃 11: Butyl acrylate - acrylonitrile - acrylic acid = 50:40:10 〃 12: Methyl acrylate - butyl methacrylate = 60:40 〃 13: Methyl methacrylate - ethyl acrylate - methacrylic acid = 40:50:10 〃 14: Methyl methacrylate - 2-ethylhexyl methacrylate - methacrylic acid =
40:50:10. Next, photosensitive liquids A and A prepared in Example 1 were prepared.
In place of copolymer 1, copolymer 2, 3,
4. A photosensitive liquid substituted with Epicoat-1031 (manufactured by Ciel Co., Ltd.) and copolymers 5 to 14 was applied to the aluminum plate-1 used in Example 1 using a rotary coater, and a total of 5 types of photosensitive planographic plates were prepared. Got the print version. These printing plates were exposed in the same manner as in Example 1,
It was developed (using developer-1) to obtain a lithographic printing plate. Each of the obtained lithographic printing plates was printed using the same printing machine as in Example 1, and a printing durability test using chemicals was conducted. The printing method is that after every 500 prints on high-quality paper, the printing press is stopped, the print is washed with print cleaner, and then treated with Ultra Plate Cleaner (plate cleaning chemicals, manufactured by A, B, C chemicd Co. Ltd.) The printer was left to stand for 4 minutes, rinsed with water, and then resumed printing. This operation was repeated. This result is shown in Table 5.
Shown below. As a result, in the lithographic printing plate using a resin containing 2-hydroxyethyl methacrylate as a component used in the present invention, the resin layer is less likely to be destroyed by chemicals than in the lithographic printing plate using other resins. It was confirmed that the printing durability was excellent.

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Claims (1)

[Claims] 1 A photosensitive and organic solvent-friendly diazo resin obtained by reacting a water-soluble photosensitive diazo resin obtained by a condensation reaction of a diazo compound and a carbonyl-containing organic condensing agent with a halogenated Lewis acid salt or a perhalogenated salt. A reaction product (a) that is soluble and almost insoluble in water;
and a lipophilic film-forming synthetic resin that is soluble in an organic solvent and almost insoluble in water (b), the surface of which is grained, anodized, and then sealed. 2-hydroxyethyl methacrylate-methyl methacrylate copolymer, 2-hydroxyethyl methacrylate-methyl methacrylate-butyl acrylate copolymer, and a photosensitive lithographic printing plate coated with oleophilic film-forming synthetic resin. , 2-hydroxyethyl methacrylate-methyl methacrylate-butyl acrylate-methacrylic acid copolymer and 2-hydroxyethyl methacrylate-
1. A photosensitive lithographic printing plate comprising one or more selected from methyl methacrylate-acrylonitrile-methacrylic acid copolymers.