JPS5938746A - Photosensitive lithographic plate - Google Patents

Abstract

PURPOSE:To prevent stains on unexposed part, by incorporating benzophenone or its deriv. in a photosensitive compsn. composed of a diazo resin oreg. or inorg. salt and a polymer compd. soluble in an org. solvent. CONSTITUTION:0.1-50wt% benzophenone or its deriv. is incorporated in a photosensitive compsn. consisting of a diazo resin org. or inorg. salt and a polymer compd. soluble in an org. solvent. As said polymer compd., an epoxy, polybutyral, styrene-maleic anhydride copolymer, shellac, a multi-component polymer of acrylic or its deriv. resins, etc. are usable.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a photosensitive lithographic printing plate Generally, a diazo resin obtained by condensation polymerization of 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 onto a support (aluminum plate, etc.) and exposed to light through a negative chip, the exposed area becomes insoluble in water, and if this resin is developed with water, the surface of the support becomes A positive image is obtained, which accepts fatty printing inks in the presence of fountain solution. Typical diazo resins include formaldehyde condensates of T)-diazodinoenylamine. JIJ with 1° coating of diazo resin only on the support
Plate materials are also available, pE, 'rV Public Ill' (47-116
7. As stated in Special Publication No. 5G-30859,
A diazo resin organic salt or diazo resin inorganic salt is made by reacting a diazo resin with an organic coupling agent or an inorganic coupling agent, and a mixture of this, an organic solvent-soluble resin, and a dye is applied onto a support. There are known plate-making materials.

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, a dark reaction occurs.
It becomes a bag in a few days, making it impossible to develop unexposed areas easily, and causing stains in non-image areas2. Attempts have been made to add phosphoric acid, citric acid, tartaric acid, etc., but no significant effects have been found in any of them.

The present invention has been solving the above drawbacks for several months.

The purpose of the present invention is to provide a photosensitive composition that does not cause stains on unexposed areas even after exposure to light or even after several days have passed under harsh conditions. A photosensitive lithographic printing plate characterized by having a photosensitive layer made of a photosensitive composition made of a solvent-soluble polymer compound containing 0.1 to 50% by weight of benzophenone and/or a benzophenone derivative.

The size of the diazo resin organic salt or diazo resin inorganic salt used in the present invention is Japanese Patent Publication No. 42-5364, Japanese Patent Publication No. 47-1167
, Japanese Patent Publication No. 39-17602 and Japanese Patent Application Publication No. 54-98613, acidic aromatic compounds (e.g., benzene, phosphinic acids, postboxylic sulfonic acids, and carboxylic acid compounds of toluene and naphthalene, and their derivatives), aromatic compounds containing linear or hydroxyl groups (e.g., 2-hydroxy-4
-Methoxybenzophenone, 2+2”/Hydroxy4
, 4'-dimethquine penzophenone, 2-hydroxy-
4-methquine benzophenone-5-sulfonic acid, 2-hydroxy-4-methoxybenzophenone-5-sulfonic acid trihydrate) or inorganic compounds (e.g. hexafluorophosphoric acid, polyhydrofluoric acid, boron fluoride) It is made insoluble in water but soluble in organic solvents by reacting acids, hydrofluorosilicic acid, boronic acid, potassium thionanate, and sodium thiocyanate.

Examples of organic solvent-soluble polymer compounds used in the present invention include epoxy resin, polybutyral resin, and styrene resin.
Among maleic anhydride copolymer resins, dieck resins, multi-component acrylic resins, and derivatives thereof, acrylic resins described in US Pat. No. 4,282,301 are particularly preferred. Moreover, the above-mentioned polymer compounds can be used alone or in combination of two or more.

Furthermore, in the present invention, a plasticizer and a dye can be added as necessary.

Does the dye make the support and image area bright after development? 1i to make it distinguishable, and it is not preferable to use a material that causes color loss in the image area during development or reacts with the diazo photosensitive material or organic polymer compound. Therefore, preferred examples include Oil Blue $603 (manufactured by Orient Chemical Industry Co., Ltd.) and Victoria Blue Bα1.
(manufactured by Hodogaya Chemical Industry C Co., Ltd.), crystal violet, crystal blue, methylene blue, malachite green, etc. can be used.

Benzophenone and its derivatives used in the present invention include benzophenone, methylbenzophenone, 2.4
-dihydroxybenzophenobenzophenone, 2.2'
, 4,4'-tetrahydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone-5-sulfonic acid and its amine salt, 4-methyl-benzophenone-
Salts of 2-carboxylic acid, 3-nitro-4-chlorobenzophenone-2-carboxylic acid, 2-hydroxy-4-methoxybenzophenone-5-sulfonic acid and p-diazodiphenylamine, or similar compounds such as benzyl can be mentioned.

Paper, plastic film, zinc, copper, aluminum, stainless steel, or a composite material made of a combination of two or more of these can be used as a support to which the photosensitive composition of the present invention is applied. An aluminum plate whose surface is anodized can be suitably used.

Dissolving the photosensitive composition using an organic solvent, for example, a mixture of methyl cellosolve, ethyl cellonolp, dimethyl formamide, dimethyl sulfoxide, methanol, methylene chloride, methyl cellosolve acetate, ethyl cellosolve acetate,
The solution is applied to a support and dried.

For development, an aqueous solution of an inorganic or organic alkali, such as sodium silicate, potassium silicate, caustic soda, potassium hydroxide, monoethanolamine, jetanolamine, triethanolamine, etc., can be used as a developer, and an anionic interface. It is preferable to contain a surfactant and an organic solvent.

Examples are shown below.

Example 1 Under a nitrogen stream, 0.3 y of azobisisobutyronitrile was added to 150 y of dioxane and heated to 80 to 85°C, into which 50 y of 2-hydroxy-3-phenoxypropylacrylate and methyl methacrylate were added. 25y
A mixed solution of 1 acrylonitrile 10P1 and methacrylic acid 2y was added dropwise while stirring. After the dropwise addition was completed, stirring was continued for 3 hours, and 150 y of dimexane was added, followed by pouring into water to precipitate the copolymer. The precipitate was filtered and
It was dried at ℃ to obtain a copolymer (1).

Next, an IS (class 1 special grade) aluminum plate having a thickness of 0.25 mm was degreased by immersing it in a 10% caustic soda solution at 70° C. for 10 seconds. Next, it was grained using a nylon brush, etched with a mixed solution of 5 qb caustic soda and 20% IJ sodium phosphate at 70° C. for 10 seconds, and washed with water. After that, in a 10% sulfuric acid solution, the current density was 2A/
drrr? After anodic liquefaction for 2 minutes and washing with water, a film treatment was carried out at 70°C for 30 seconds with a 5% sodium silicate solution 1- An anodized aluminum plate (1) was prepared. A photosensitive liquid with (
5) and (B) were applied and dried.

Composition of photosensitive liquid (4) Methyl cellosolve 60y
Copolymer (1) 15y Dodecylbenzenesulfonate of condensate of p-diazodiphenylamine and paraformaltehyde
1.5y Victoria Blue BOH 0.4y A photosensitive solution (B) was prepared by adding 1.01 ml of benzophenone to the above photosensitive solution (5). The aluminum plate (1) coated with photosensitive liquid, [F]n, was printed as a printing plate (5)-(1), ff, respectively.
3>-1. Each of the printing plates (A-1 and (B)-1) was left in a constant temperature and humidity chamber at 45°C and 75% humidity for 5 days, and then passed through a negative film for 2y.

Using a high-pressure mercury lamp, exposure was performed for 45 seconds at a distance of 1 m. Next, it was immersed in a developer having the composition shown below at 5° C. for 1 minute, and then washed with water.

Composition of developer Sodium silicate 40% aqueous solution 5y
Sodium isopropyl naphthalene sulfonate 2y Potassium sulfite 1y Phenyl glycol 5y Water
2371
When printing was carried out using the developed printing plates (A)-1 and (B)-1 as plates, in the printing plate-1,
Although stains occurred on the non-printing area of the printing surface, printing plate (B)
-1, good printing without stains was obtained.

Example 2 An aluminum plate (110(+)) with a thickness of 0.25 mm and a width of 1000 ia was degreased with alkali and washed with water.
Brush polished using polish. Next, thoroughly remove the polishing residue in a 10% caustic soda bath, wash with water for 1 to 2 hours, and then chlorinate with 2.5% hydrochloric acid).
20°C) for 10 seconds at a current density of 10A/(Irr+') with an alternating current of 0[.
℃) at a current density of 2A/Ya for 60 seconds,
After washing with water, in a 5% potassium silicate bath (40°C),
1 [AC anodizing treatment was performed again for 15 seconds at a flow density of 2 A/d, A, and an anodized aluminum plate (2) was obtained by washing with water and drying.

The following photosensitive solution was applied to this aluminum plate (2) and dried.

Composition of photosensitive liquid (C) Methyl cellosolve 50
ydimethylformamide JO
y copolymer (1)
]! Potassium thiocyanate salt of condensate of 5Pp-diazodiphenylamine and paraformaldehyde
A photosensitive solution (D) is prepared by adding 1.5 F of 2-hydroxy-4-methoxybenzophenone-5-sulfonic acid amide/salt to 1.5" Oil Blue #603 O, SP photosensitive solution. Aluminum plates (2)f: coated with photosensitive solutions (C) and (r)) were used as printing plates (C)-2 and (D)-2, respectively.

Printing plates (C)-2 and 2)-2 were left in a constant temperature and humidity chamber at 45° C. and humidity 75 eIb for 5 days, and then exposed and developed in the same manner as in Full 1. The developed printing plate (0-2, (DI-2) was used as the plate for printing, and in the printing plate (C)-2, stains occurred in the non-printing area, but in the printing plate Q))-2, stains appeared. , a good print with no stains was obtained.

As is clear from the above examples, the printing plate having the photosensitive layer of the present invention has good printing characteristics.

Procedural amendment (voluntary) November 19, 1981 YulV5'. 7゜ 6ゎo. Ei '1, Indication of the Case 1982 Patent Application No. 149005 υ.

2. Name of the invention Photosensitive lithographic printing plate 3. Person making the amendment Relationship with the case Address of the patent applicant 4 Agent address: 107 and 2 others Contents of the amendment (11 Mei 111, page 2, line 11) Correct "organic coupling port" to "organic coupling agent-1" (2)
On the same day, the second line from the bottom of the same book is corrected to read ``Bagification - 1 is 1 deterioration''.

(3) 1trJ 1. I'? t44 N Correct "bosphonic acid, sulfonic acid" in the 4th line to "1posonic acid, sulfonic acid".

(4) Same ν [10th ward, 3rd line to v, 4th line 1-
"Stonpowter" is corrected to "Carborundum".

Claims (1)

[Claims] A photosensitive composition consisting of a diazo resin organic salt or a diazo resin inorganic salt and an organic solvent-soluble polymer compound is
1. A photosensitive lithographic printing plate comprising a photosensitive layer containing 0% by weight of benzophenone and/or benzophenone/derivative.