JP3308378B2 - Processing solution for offset printing plate - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an offset printing plate using a silver image as ink acceptability, and more particularly to a processing solution for a direct offset printing plate using a silver complex salt diffusion transfer method. It is intended to improve the ink receptivity of the formed silver image. Specifically, offset printing used for the purpose of improving the ink receptivity of the silver image itself by processing the silver image of the offset printing plate formed by the diffusion transfer method at an arbitrary stage in the printing process as appropriate with a specific processing agent. It relates to a plate processing solution.

[0002]

2. Description of the Related Art Offset printing plates which form a silver image using the principle of photography and utilize the ink receptivity of the silver image have been well known. For example,
No. 29723 and No. 51-15762 disclose a technique for further improving the ink receptivity of a silver image by treating the silver image with a lipophilic agent containing a certain organic mercapto compound. . However, the mercapto compound used here has extremely low solubility in neutral water, and is difficult to dissolve in an alkaline aqueous solution in which an alkali metal hydroxide or the like is dissolved or an organic solvent such as alcohol, THF, DMF, or acetone. Must be dissolved and used in a mixed solution. As another method of use, it is necessary to dissolve in a high-boiling organic solvent in advance and use this as an oil-in-water dispersion emulsion.

In recent years, organic solvent free in the printing plate processing step has been strongly demanded for environmental reasons, and a neutral aqueous solution type is desired as a plate surface treatment liquid. The mercapto compound described in the above patent has a high pKa, and a satisfactory result cannot be obtained in a treatment solution containing no organic solvent or alkali. Further, the demands on the printing image quality of the printing plate are increasing year by year, and a processing solution containing a compound that allows the image portion of the printing plate to receive the ink sufficiently in a short time and does not cause background staining of the non-image portion is strongly desired. ing.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide an offset printing plate processing solution containing an oleophilic agent for improving the ink receptivity of a silver image. An object of the present invention is to provide a processing liquid which improves the ink receptivity of an image and has less background stain on a non-image portion.
Another object of the present invention is to provide a processing solution for an offset printing plate which does not contain an organic solvent and improves the ink receptivity of a silver image by using a lipophilic agent having high water solubility.

[0005]

The object of the present invention has been attained by incorporating a compound represented by the formula (3) or a compound represented by the formula (4) into a treatment liquid as an oleophilic agent.

[0006]

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[0007]

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In the formula, l is an integer of 1 or more, and m is 2 to
And n is an integer of 1 to 6. A is a hydrogen atom, a halogen atom such as chlorine or bromine, or a hydroxy group, or an acyloxy group such as an acetoxy group. X is a halogen atom such as chlorine and bromine.

The present compound has a partial structure of thioether in the molecule and improves the ink receptivity by adsorbing on a silver image to modify the surface of the silver image. The N-terminal alkyl group (Cn H2n + 1) may be linear or have a side chain, but is preferably a linear one. Also,
For m and n, any integer of l = 1 or more, m = 2 or more, and n = 1 or more can be selected. When m is 5 or more and n is 7 or more, the ink receptivity of the silver image is improved. The effect is weak and the solubility in water is also poor. When the value of l is equal to or more than 5, the effect of improving the ink receptivity is also weakened. Hereinafter, typical compounds used in the present invention will be described, but the present invention is not limited thereto.

Examples of compounds of formula

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Example of compound of formula 4

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[0030]

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[0031]

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[0034]

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[0036]

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[0040]

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[0041]

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[0042]

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[0043]

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The synthesis of the compound of formula 3 of the present invention is basically carried out by adding the mercapto group of the corresponding mercaptotetrazole
1,2-dichloroethane, 1,2-dibromoethane, 1
It can be easily synthesized by alkylation with an alkyl halide such as -chloro-2-bromoethane or 2-bromoethanol. The synthesis of the compound of formula 4 of the present invention is represented by formula 3
Can be synthesized by treating the compound with hydrochloric acid or the like. The details of the synthesis method are described below using synthesis examples.

Synthesis Example 1 Synthesis of Chemical Formula 1 45 g of 1- [2- (di-n-butylamino) ethyl] -5-mercapto-tetrazole was dissolved in a mixture of 500 ml of methanol and 88 ml of 2N NaOH aqueous solution. And 25 g of 1-bromo-2-chloroethane were added and the mixture was heated under reflux for 20 hours. After cooling, methanol was distilled off from the reaction mixture under reduced pressure, water was added to the residue, and the mixture was extracted twice with 100 ml of chloroform. The chloroform layer was washed with water and dried over anhydrous Na ₂ SO ₄ , and chloroform was distilled off under reduced pressure to give 1- [2- (di-n-
Butylamino) ethyl] -5- (2-chloroethylthio) tetrazole (56 g) was obtained as a yellow oil.

¹ H-NMR (CDCl ₃ ): δ (ppm)
_{0.88 (6H, t, CH 3} ) 1.26 (8H, m, CH 2) 2.41 (4H, m,
_{CH 2) 2.88 (2H, m} , CH 2) 3.64 (2H, t,
_{CH 2) 3.92 (2H, t} , CH 2) 4.25 (2H, t,
CH ₂ )

¹³ C-NMR (CDCl): δ (ppm),
_{13.8 (CH 3) 20.2 (CH} 2), 29.0 (CH 2), 35.2
_{(CH 2) 42.2 (CH 2} ), 46.3 (CH 2), 52.7
_{(CH 3) 53.9 (CH 2} ), 153 (C- heterocycle)

Synthesis Example 2 Synthesis of 1- [2- (di-n-butylamino) ethyl] -5-mercapto-tetrazole 40 g of methanol 500 ml
And a 2N NaOH aqueous solution in a mixture of 80 ml.
-Bromoethanol (20 g) was added, and the mixture was heated under reflux for 18 hours. After cooling, methanol was distilled off from the reaction mixture under reduced pressure.
Water was added to the residue, and extracted twice with 100 ml of chloroform. The chloroform layer was washed with 50 ml of 0.5N NaOH.
After washing twice, it was dried over anhydrous Na ₂ SO ₄ and chloroform was distilled off under reduced pressure. The remaining oil is subjected to silica gel column chromatography (chloroform / methanol = 20/1).
To give 28 g of 1- [2- (di-n-butylamino) ethyl] -5- (2-hydroxyethylthio) -tetrazole as a pale yellow oil.

¹ H-NMR (CDCl ₃ ): δ (ppm)
_{0.88 (6H, t, CH 3} ) 1.26 (8H, m, CH 2) 2.43 (4H, m,
_{CH 2) 2.89 (2H, t} , s, CH 2) 3.35 (1H,
br.s, OH) 3.46 (2H, t, CH 2) 3.98 (2H, t,
CH ₂ ) 4.28 (2H, t, CH ₂ )

¹³ C-NMR (CDCl ₃ ): δ (ppm
_{), 13.9 (CH 3) 20.4} (CH 2), 29.1 (CH 2), 36.3
_{(CH 2) 46.3 (CH 2} ), 52.8 (CH 2), 54.2
_{(CH 3) 61.5 (CH 2} ), 154.1 (C- heterocycle)

Synthesis Example 3 Synthesis of 1- (2-dimethylaminoethyl) -5- (2-hydroxyethylthio) -tetrazole 22 g of acetic anhydride 18
0 ml, add 10 g of sodium acetate and add
And heated to reflux for 10 hours. Acetic anhydride was distilled off under reduced pressure, the residue was dissolved in toluene, and the insoluble matter was separated by filtration. After the toluene was distilled off under reduced pressure, the residue was purified by column chromatography (chloroform / methanol = 40/1) to give 1-
20 g of (2-dimethylaminoethyl) -5- (2-acetoxyethylthio) -tetrazole was obtained as a pale yellow oil. This was dissolved in 200 ml of THF, and the precipitated white solid was collected by filtration through hydrogen chloride gas under ice-cooling, washed with ether, and washed with 1- (2-dimethylaminoethyl) -5--5.
21 g of (2-acetoxyethylthio) -tetrazole were obtained as the hydrochloride. 1- (2-dimethylaminoethyl)
-5- (2-Hydroxyethylthio) -tetrazole was synthesized according to (Chemical Formula 14) using 1- (2-dimethylaminoethyl) -5-mercaptotetrazole.

¹ H-NMR (DMSO, d6): δ (ppm)
_{1.99 (3H, s, CH 3} ) 2.82 (6H, s, CH 3) 3.57 (2H, t,
CH ₂ ) 3.62 (2H, t, CH ₂ ) 4.34 (2H, t,
_{CH 2) 4.79 (2H, t} , CH 2) 11.3 (1H, br.
s, NH ₂ ) ¹³ C-NMR (DMSO, d6): δ (ppm) 20.5
_{(CH 3) 31.9 (CH 2} ), 41.8 (CH 2), 42.2
_{(CH 2) 53.4 (CH 2} ), 62.0 (CH 2), 153.7
(C-heterocycle) 170.1 (C = O)

The compound of the present invention is added to an aqueous processing solution containing no organic solvent and processed to improve the ink receptivity of a silver image and to reduce the background stain in a non-image area.
In particular, the mineral salts are advantageous because they are well soluble in neutral aqueous solutions and can be applied at high concentrations. Alcohols, T
Even if an organic solvent such as HF and DMF coexists, the effect does not change.

The compound of the present invention is most effective when processed in the form of a solution after the development processing. However, it may be added to a developer or a stop solution to improve the ink receptivity of the plate. it can.

The concentration of the lipophilic agent added to the treatment liquid of the present invention is 0.1 to 10 g / l, preferably 0.5 g to 1 g.
5 g / l. Further, additives such as thickeners can be used in combination, but these are not essential elements. The processing liquid of the present invention improves the ink receptivity of the silver image area of the printing plate, while also reducing the background stain of the non-image area. Further, the processing solution is also excellent in stability over time.

An offset printing plate utilizing the silver image of the present invention as ink acceptability is disclosed in JP-B-48-3056.
No. 2, JP-A-53-21602, U.S. Pat.
In addition to 1,559 and 3,490,905, offset printing plates having a silver halide image as ink acceptability, such as U.S. Pat. No. 3,454,398 and JP-A-53-9603, are included. Is done. Hereinafter, the present invention will be described specifically with reference to Examples.

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【Example】

Example 1 Lithographic printing without any modification except that the physical development nucleus layer of the offset printing plate (plate No. 3) described in Example 1 of JP-A-53-21602 contains hydroquinone at 1.0 g / m ^2. Materials were made. The lithographic printing material is imagewise exposed, immersed in a developer of the following formulation at 30 ° C. for 30 seconds, and subsequently immersed in a stop solution of the following formulation for 30 seconds (25 ° C.), squeezed to obtain an excess solution. And dried in air at room temperature.

<Developer> Water 700 ml Sodium hydroxide 20 g Anhydrous sodium sulfite 60 g Potassium bromide 0.5 g 2-mercaptobenzoic acid 10 mmole 2-methyl-2-amino-1-propanol 10 g Water is added to make 1 liter.

<Stop solution> 2 l of water 10 g of citric acid 35 g of sodium citrate

The printing plate obtained in this manner was used for offset printing machine AB Dick 350CD (AB Dick 3).
50CD (trade name), and after the plate surface was etched with the liquid of formula (E), printing was performed using a humidifying liquid having the following composition.

Treatment liquid (E) Exemplary compound 1 g Ethylene glycol 50 g Water 1000 ml

<Humidifying liquid> (The used liquid is diluted 10-fold with water) Water 300 ml Succinic acid 6 g Sodium sulfate 25 g Ethylene glycol 100 g Colloidal silica (20% aqueous solution) 28 g

The ink receiving characteristics and the ease with which dirt was produced were determined by the following methods. 1) Ink receiving characteristics The number of prints until a printed matter is obtained with a good image density by starting paper feeding at the same time when the inked roller is brought into contact with the plate surface. 2) Evaluation of dirt The printing was performed on 1,000 sheets, and evaluation was made on the following three levels based on the degree of dirt on the printed matter at that time. ○ No dirt occurs. △ Partial or thin stains × Completely thin stains Also, as a comparative compound,
Chemical formula 38 was used.

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Table 1 summarizes the evaluation results.

[0067]

[Table 1]

As is clear from Table 1, the compounds of the present invention have high solubility in water and improve the ink receptivity of silver images.

Example 2 Printing was performed in the same manner as in Example 1 except that the treatment liquid was changed to the prescription (F) and the printing plate was processed. Further, these treatment solutions were aged at 50 ° C. for 2 weeks, and then printed and evaluated in the same manner. After treating these treatment liquids at 50 ° C. for 2 weeks, plate making and printing were similarly performed and evaluated.

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Treatment liquid (F) Exemplary compound 1 g Ethylene glycol 50 g Isopropanol 400 ml Water 600 ml

Compounds 39 and 40 were used as comparative compounds. The evaluation results are shown in Tables 2 and 3. The results of the treatment solution after aging are shown in the column.

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[Table 2]

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[Table 3]

As is clear from Tables 2 and 3, the compounds of the present invention can provide a processing liquid having excellent ink receptivity and excellent stability with time.

[0077]

The processing liquid of the present invention improves the ink receptivity of the silver image area of the offset printing plate, and is also effective in reducing the background smear in the non-image area, and also in the stability of the liquid over time. Are better.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) B41N 3/08 G03F 7/07

Claims (1)

(57) [Claims] 1. A processing solution for an offset printing plate utilizing a silver image as ink receptivity, comprising a compound of formula 1 or a compound of formula 2. Embedded image (In the formula, l is an integer of 1 or more, m is an integer of 2 to 4, n is an integer of 1 to 6. A is a hydrogen atom, a halogen atom such as chlorine or bromine, or a hydroxy group. Or an acyloxy group such as an acetoxy group.) (In the formula, l is an integer of 1 or more, m is an integer of 2 to 4, n is an integer of 1 to 6. A is a hydrogen atom, a halogen atom such as chlorine or bromine, or a hydroxy group. Or an acyloxy group such as an acetoxy group.
X is a halogen atom such as chlorine and bromine. )