JPH0659457A - Treatment of planographic printing plate - Google Patents

Abstract

PURPOSE:To obtain a treating method for direct planographic printing plate corrected in the defect of a transfer silver image, extremely improved in printing resistance and free from the degradation of ink receptivity ability by the use of silver complex salt diffusion transfer method. CONSTITUTION:This treating method is about the direct planographic printing plate containing a compound expressed by the formula and a developer. In the formula, each of R1 and R2 is hydrogen atom, alkyl group and alkoxy group, R3 is univalent alkali metal, hydrogen atom or acyl group, X is divalent group containing O atom, N atom and forms 15-membered ring or 21-membered ring.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for processing a lithographic printing plate by a silver complex salt diffusion transfer method.

[0002]

2. Description of the Related Art An offset printing plate using a silver image obtained by a silver complex salt diffusion transfer method (DTR) has already been disclosed in Japanese Patent Publication No. 46-43132 or Japanese Patent Publication No. 48-3.
No. 0562, and a positive type printing original plate is disclosed in Japanese Patent Laid-Open Publication No. 49-55402.
Regarding negative type printing original plates, published patent publication Sho 52-
No. 106902, JP-A No. 52-112402, and the like.

These direct printing plates are composed of a support, an undercoat layer also serving as an antihalation layer, a silver halide photographic emulsion layer and a physical development nucleus layer on the support. When a light-sensitive material is imagewise exposed and then treated with a developer containing a developer and a silver halide solvent, the silver halide on which a latent image is formed becomes blackened in the emulsion layer. The silver halide in which the silver halide is not formed is dissolved by the action of the silver halide complexing agent and diffuses to the surface of the light-sensitive material. This silver complex salt is deposited as a silver image on the physical development nuclei of the surface layer by the reducing action of the developing agent. This process results in a direct printing plate.

In order to enhance the ink receptivity of the silver image, after development, an oil-sensitizing treatment is carried out if necessary, and the ink image is transferred to a printed matter by an offset printing machine. This direct printing plate has advantages such as good operability and low price, but on the other hand, due to the nature of forming a silver image for printing by photographic development processing, diffusion transfer is completed within the processing time. However, excessive silver ions remained, which contributed to a decrease in storage stability or printing durability.

Various methods are utilized to remedy these drawbacks. One of them is a method of using various appropriate compounds as a silver halide complexing agent. JP-A-56
Nos. -1057 and 56-9750 describe a method of adding thiosalicylic acid and a substituted derivative thereof to a processing liquid or a constituent layer of a printing plate. Ibid 56-62
Nos. 37 and 56-8145 describe a method in which thiosalicylic acid and its derivative are used in combination with an alkanolamine or a cyclic imide compound, but there are drawbacks such as reduction of ink sticking of silver images, and further improvement is desired.

Further, Japanese Patent Laid-Open No. 62-239161 describes a method in which a benzotriazole compound is used as a development inhibitor and the printing durability is improved by controlling the DTR. Although the printing durability is improved to some extent by this method, the amount of ink sticking is reduced and it has not yet reached a sufficient level. In particular, there is a need for a method that does not reduce ink sticking.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to obtain a silver image having a good printing durability and a high ink acceptability in the development processing of a direct lithographic printing plate utilizing the silver complex salt diffusion transfer method. Is to provide a processing method.

[0008]

Means for Solving the Problems As a result of intensive studies, the present inventor has conducted development and stabilization in the presence of a development inhibitor having a chelating function in the same molecule. It was found that the object of the present invention can be achieved by the above.

That is, the present invention is a method of treating a silver salt diffusion transfer lithographic printing plate in the presence of a compound represented by the following chemical formula 2.

[0010]

[Chemical 2] In Chemical formula 2, R ¹ and R ² may be the same or different,
Each represents a hydrogen atom, an alkyl group or an alkoxy group, R ³ represents a monovalent alkali metal, a hydrogen atom or an acyl group, X represents a divalent group containing an oxygen atom or a nitrogen atom, a 15-membered ring or 21 Form a member ring. Specific examples of the compound of Chemical formula 2 used in the present invention are shown below.

[0011]

[Chemical 3]

[0012]

[Chemical 4]

[0013]

[Chemical 5]

[0014]

[Chemical 6]

[0015]

[Chemical 7]

[0016]

[Chemical 8]

[0017]

[Chemical 9]

[0018]

[Chemical 10]

The compound of the present invention can be easily synthesized by a conventional method using an aniline derivative obtained by nitrating a benzocrown ether as a mother nucleus and then reducing it. The benzocrown ether which is a mother nucleus is, for example, Synthesis 680 (1986), tetrahedron. Letters (Tetrahedron Lett.) 26 2705 (1985), Chemical Communication (Chem.commun) 268 (1986), Journal of Polymer Science (J. Polymer Sci. A-1 9 817)
(1971), Journal of American Chemical Society (J. Amer. Chm. Soc.) 95 , 3842 (1973) Chemical Communication (Chem.commun) 414 (1975), 639 (1976),
It can be synthesized according to the method of 640 (1976). The synthesis examples of representative compounds of the present invention are shown below.

Synthetic Example (Synthesis of Chemical Formula 3) 24 g of benzo-15-crown-5 was added to chloroform 3
It was dissolved in 30 ml, 200 ml of acetic acid was added, 81 ml of HNO ₃ (d about 1.42) was added dropwise over 30 minutes while stirring at room temperature, and the mixture was further stirred at room temperature for 6 hours. Chloroform was added to the reaction solution, washed with water, and dried over anhydrous sodium sulfate. Chloroform was distilled off under reduced pressure to obtain crude 4-nitro compound 2
0.6 g (mp 92-94 ° C) was obtained as a pale yellow solid.

After adding 10 ml of water to 10 g of iron powder and heating to 110 ° C., 2 ml of acetic acid was added and stirred for 10 minutes. The mixture was dispersed in 50 ml of dioxane and stirred at an internal temperature of 85 ° C to 95 ° C for 30 minutes. At the same temperature, 10 g of the nitro body is 100 ml of dioxane
The solution dissolved in was added dropwise over 2 hours, and then at the same temperature 1
Stir for hours. After cooling, 20 ml of acetic anhydride was added. After filtering the insoluble matter, dioxane was distilled off under reduced pressure to obtain a crude product. Column chromatography (silica gel / C
Separated with HCl ₃ : MeOH = 20: 1). The crystals were recrystallized from methanol to give 6.2 g of 4-acetamino compound (mp 15
0-151.5 ° C) was obtained as colorless crystals.

1.8 g of acetamino compound was dissolved in 5 ml of acetic anhydride, and concentrated HNO ₃ (d = 1.
38) 1.1 ml was added dropwise over 2 hours. The mixture was returned to room temperature and further stirred for 1 hour. Acetic anhydride was distilled off under reduced pressure, and the obtained solid was washed with methanol to obtain a crude product. Recrystallize with chloroform and methanol to give 4-acetamino-5
-1.45 g of nitro compound (mp 179-180 ° C) was obtained as yellow crystals.

1.8 g of 4-acetamino-5-nitro compound
Was dissolved in 19 ml of ethanol and 1.9 ml of water, 330 ml of potassium hydroxide was added, and the mixture was refluxed for 4 hours. After allowing to cool, the mixture was neutralized with carbon dioxide at room temperature, the solvent was distilled off under reduced pressure, the residue was dissolved in methanol, the insoluble matter was filtered off, and the methanol was distilled off under reduced pressure. Column chromatography of the residue (silica gel /
It was separated with CHCl ₃ : MeOH = 20: 1) and 0.82 g of 4-amino-5-nitro compound (mp 145.5-147).
C) was obtained as orange crystals.

After adding 1 ml of water to 1.63 g of iron powder and heating to 110 ° C., 0.4 ml of acetic acid was added and stirred for 10 minutes. 5 ml of dioxane was added to this, and the internal temperature was 85-9.
The mixture was stirred at 5 ° C for 30 minutes. A solution prepared by dissolving 1.47 g of 4-amino-5-nitro derivative in 5 ml of dioxane at the same temperature was 1.
It dripped over 5 hours. Further, the mixture was stirred at the same temperature for 1 hour.
After cooling, the insoluble matter was filtered off, and 2.5 ml of concentrated hydrochloric acid was added to the filtrate. The precipitated crystals were collected by filtration to obtain 0.78 g of crude 4,5-diamino dihydrochloride as colorless crystals.

To 0.78 g of 4,5-diamino dihydrochloride, 1 ml of water and 0.6 g of sodium acetate trihydrate were added and well stirred, and then 0.25 g of acetic acid was added. At room temperature,
A solution prepared by dissolving 0.17 g of sodium nitrite in 1 ml of water was added all at once and stirred for 1 hour. The reaction solution was extracted with chloroform, and the chloroform was distilled off under reduced pressure to obtain a crude product. This is subjected to column chromatography (silica gel / CHCl
Separation with ₃ : MeOH = 100: 1) gave compound 3.

Yield 0.23 g mp 182-183 ° C. 1H NMR (DMSO, δ) 3.65 (8H, S),
3.82, 3.84 (4H, dd, J = 6.1, 6.
7 Hz) 4.12, 4.14 (4H, dd, J = 6.7, 6.
1 Hz) (above methylene hydrogen) 7.2 to 7.3 (2H, bs, benzene nucleus hydrogen)

¹³ CNMR (DMSO, δ) 68.2
68.4, 69.0, 69.7 (above methylene carbon) 97.2, 136.4, 147.1 (above benzene nucleus carbon)

Synthetic Example (Synthesis of Chemical Formula 11) 64.5 ml of acetic anhydride was added to 24.5 g of 3,4-methylenedioxyaniline and left overnight. Acetic anhydride was distilled off under reduced pressure, and the precipitated crystals were collected by filtration, washed with water and dried 3,4-
29.2 g of crude product of methylenedioxyacetanilide
Was obtained as brown crystals.

29 g of 3,4-methylenedioxyacetanilide was dissolved in 100 ml of acetic anhydride, and 84 ml of concentrated nitric acid (d = 1.38) was added dropwise over 2 hours at −10 ° C. with stirring (the content was obtained when 10 ml was added). Since the substance had solidified, 88 ml of acetic acid was added as a solvent and the dropping was continued). The mixture was returned to room temperature and further stirred for 1 hour. The obtained solid was collected by filtration and washed with methanol to obtain a crude product. Recrystallization from chloroform / methanol gave 30 g of 6-nitro-3,4-methylenedioxyacetanilide as yellow crystals.

After adding 250 ml of ethanol to 25 g of 6-nitro-3,4-methylenedioxyacetanilide, a solution of 7.5 g of potassium hydroxide in 25 ml of water was added at 40 ° C.
Then, the mixture was heated for 30 minutes. The mixture was washed with water using a separating funnel and extracted with chloroform. The crystals precipitated at that time were combined with the crystals obtained by extracting chloroform after the extraction with chloroform, and recrystallized with methanol. 17.1 g of 6-nitro-3,4-dioxyaniline (mp 198.5-199.
5 ° C.) was obtained as orange crystals.

17 ml of water was added to 33.3 g of iron powder, and 110
After heating to ° C, 6.8 ml of acetic acid was added and stirred for 10 minutes. 70 ml of dioxane was added thereto, and the mixture was further stirred at an internal temperature of 85 to 90 ° C for 30 minutes. 6-nitro-at the same temperature
16.7 g of 3,4-dioxyaniline was added to dioxane 10
The solution dissolved in 0 ml was added dropwise over 1.5 hours. Further, the mixture was stirred at the same temperature for 1 hour. After cooling, the insoluble matter was filtered off, and 42.5 ml of concentrated hydrochloric acid was added to the filtrate. The precipitated crystals were collected by filtration and washed with a solution of methanol: ethanol = 1: 1 to give 1,2-
Diamino form dihydrochloride 19.3 g (dec.-220 degreeC)
Was obtained as light purple crystals.

To 8.3 g of the 1,2-diamino dihydrochloride, 4.1 ml of water and 10 g of sodium acetate trihydrate were added and well stirred, and then 4.4 g of acetic acid was added. At room temperature, a solution of 2.8 g of sodium nitrite in 4.1 ml of water was added all at once, and the mixture was stirred for 1 hour. The reaction solution was extracted with chloroform, and the chloroform was distilled off under reduced pressure to obtain a crude product. Column chromatography (silica gel / C
It was separated with HCl ₃ : MeOH = 100: 1) to obtain 5,6-methylenedioxybenzimidazole compound 11.

Yield 1.92 g mp 211-212 ° C. 1HNMR (DMSO, δ) 6.12 (2H, s, methylene hydrogen) 7.28 (2H, s, benzene nucleus hydrogen) around 3.4 (1H, bs, -NH)

The amount of the compound of formula 2 of the present invention added to the developing solution is in the range of 10 ^-5 to 10 ^-1 mol / l, preferably 10 ^-3 to 10 ^-2 mol / l. Further, two or more kinds of compounds can be used in combination.

The compound of the present invention is most effectively added to a developing solution, but a processing solution such as a stabilizing solution, a silver halide emulsion layer or a physical development nucleus layer of a direct printing plate, preferably a silver halide. It may be added to the emulsion layer. In that case, the addition amount is in the range of 10 ⁻⁷ to 10 ⁻³ mol / m ² , and preferably 10 ⁻⁶ to 10 ⁻⁴ mol / m ² . Further, two or more kinds of compounds can be used in combination. The addition to the treatment liquid is preferably carried out by dissolving in an organic solvent. The same applies when it is added to the emulsion.

The developing solution of the present invention contains an alkaline substance (sodium hydroxide, potassium hydroxide, sodium triphosphate, etc.) and a sulfite salt (potassium sulfite, as a preservative).
Sodium sulfite, etc.) is essential, but other compounds such as sulfates (sodium sulfate, ammonium sulfate, etc.), antifoggants (potassium bromide, etc.), silver halide solvents (thiosulfates, thiocyanates, thioethers) , Cyclic imide, thiosalicylic acid, alkanolamine, etc.), developing agent (hydroquinone, 1-phenyl-3)
-Pyrazolidone, methol, etc.) and development accelerators (polyoxyalkylene compounds, onium compounds, etc.).

Further, one or more kinds of surfactants (propylene glycol alginate, etc.), aminopolycarboxylic acid salts (sodium ethylenediaminetetraacetate, etc.) and the like can be contained. In addition to these, a solvent for the compound of the present invention, for example, a water-miscible organic solvent such as methanol, ethanol, propanol, isopropyl alcohol, n-butyl alcohol, DMF, dioxane and the like can be included.

In carrying out the silver complex salt diffusion transfer method, for example, British Patent Nos. 1000115 and 1012476.
No. 1017273, 1042477, the incorporation of a developing agent into the silver halide emulsion and / or the image receiving layer or other water permeable layer adjacent thereto has been carried out. There is. Therefore, in such a light-sensitive material, the processing solution used for development may be a simple alkaline solution containing no developing agent. The compound of the present invention is also effective in such a type of sensitive material.

The silver halide emulsion of the lithographic printing plate used in the practice of the present invention may be silver chloride, silver bromide, silver chlorobromide, silver chloroiodide or silver chlorobromoiodide, preferably silver chloride. Is 50
It is a silver halide of mol% or more. These silver halide emulsions are spectral sensitizers (spectral sensitizing dyes depending on the light source and application, such as camera type, laser light type, panchromatic type for color separation), gelatin hardening agents, coating aids, antifoggants. , A plasticizer, a developing agent, a matting agent and the like.

The binder used in the silver halide emulsion of the lithographic printing plate of the present invention is usually gelatin, and a part of gelatin is starch, albumin, sodium alginate, hydroxyethyl cellulose (HEC), natural gums such as gum arabic and the like. Polymer, polyvinyl alcohol (P
VA), polyvinylpyrrolidone (PVP), carboxymethyl cellulose (CMC), polyacrylamide, styrene-maleic anhydride copolymer and the like may be substituted with one or more synthetic polymers.

An undercoat layer may be included on the lower side (support surface) of the silver halide emulsion layer for the purpose of improving adhesion and / or preventing halation. This layer may contain a developing agent and a matting agent. I can.

The support on which the silver halide emulsion is coated is
Paper, various films, plastics, paper coated with resin-like substances, metal plates, etc. can be used.

The physical development nuclei used in the physical development nuclei layer are
Well-known drugs such as antimony, cadmium, cobalt,
Metals such as palladium, nickel, silver, lead and zinc and their sulfides can be used. The physical development nucleus layer may also contain a developing agent and may contain a hydrophilic binder.

[0044]

The present invention will be described in more detail with reference to the following examples, but the invention is not limited thereto.

An undercoating-treated polyester film support is provided on one side with a matting layer containing silica particles having an average particle size of 5 μ, and on the opposite side, carbon black is included to reduce the light reflectance. An anti-halation subbing layer (adjusted to pH 4.0) containing silica powder having a diameter of 7μ at a ratio of 20% by weight with respect to photographic gelatin, and a silica powder having an average particle diameter of 7μ after chemically sensitized was used as photographic gelatin. And a spectrally sensitized high-sensitivity silver chloride emulsion layer (adjusted to pH 4.0) were provided. The subbing layer was made of gelatin at 3.5 g / m ² , and the emulsion layer was made of gelatin.
8 g / m ² and silver halide (converted to silver nitrate) 1.0 g /
It was applied at a rate of m ² . The subbing layer and the emulsion layer contain formalin as a hardener at a ratio of 5.0 mg / g with respect to gelatin.

After drying, the mixture was heated at 40 ° C. for 14 days, then the emulsion was coated with the nuclear liquid described in Plate No. 31 used in Example 2 of JP-A-54-103104 and dried. , Produce lithographic printing plates. The silver halide emulsion was prepared by adding 4 × 10 ⁻⁶ mol of rhodium chloride per mol of silver halide during physical ripening, and had an average grain size of 0.40 μm.
Met. The lithographic printing plate precursor thus obtained was image-exposed with a plate-making camera having an image reversal mechanism, developed with the following developer (use solution) at 30 ° C. for 30 seconds, and then with the following neutralizing solution. Processed.

Developer A Sodium hydroxide 24 g Potassium hydroxide 8 g Anhydrous sodium sulfite 50 g 2-Methyl-amino-1-propanol 30 g Uracil 0.2 g Water is added to make 1 liter.

Neutralizing solution Ethylene glycol 5 g Colloidal silica (20% aqueous solution) 1 g Citric acid 10 g Sodium citrate 35 g Water is added to make 1 liter.

On the other hand, in addition to the developer A, the following comparative compounds 11 and 12 or the exemplified compounds of the present invention were added at a ratio of 2 × 10 ^-3 mol per liter of the developer, and the developer B was added.
-I was prepared.

[0050]

[Chemical 11]

[0051]

[Chemical 12]

The development was carried out in the same manner as the above-mentioned developing solution A, and a plate-making process was carried out. Then, the printing plate was set in an offset printing machine, the plate surface was sufficiently wetted with an etchant having the following composition, and printing was performed using a dampening liquid having the following composition.

Etching solution Water 600 ml Isopropanol 400 ml Ethylene glycol 50 g

Humidifying liquid Water 8 l Succinic acid 6 g Sodium sulfate 25 g Ethylene glycol 100 g Colloidal silica (20% aqueous solution) 28 g

The printing results of the examples judged according to the following criteria are shown in Table 1. The printing durability of printing was determined by the following method. Printing was continued from 1,000 sheets to 50,000 sheets, and the following four levels were evaluated according to the number of printed sheets when ink bleeding occurred in the silver image area. A 50,000 sheets or more B 25,000 C 10,000 D 5,000

[0056]

[Table 1]

As is clear from Table 1, the lithographic printing plate obtained by adding the compound of Chemical formula 2 produced a silver image with dramatically excellent printing durability, and reproduced well the fine line portions of the original. Moreover, it was able to withstand long printing without mechanical abrasion due to printing of the fine line portion.

[0058]

EFFECTS OF THE INVENTION The planographic printing plate produced by the processing method of the present invention is improved in the lack of transferred silver image, the printing durability is remarkably improved, and the ink receiving ability is not deteriorated.

Claims (1)

[Claims] 1. A method of treating a lithographic printing plate utilizing a silver complex salt diffusion transfer method under conditions in which at least one compound represented by the following chemical formula 1 is present. [Chemical 1] (In the formula, R ¹ and R ² are each a hydrogen atom, an alkyl group,
Representing an alkoxy group, R ³ is a monovalent alkali metal, a hydrogen atom or an acyl group, and X is a divalent group containing an oxygen atom or a nitrogen atom, and forms a 15- or 21-membered ring. )