JPH02103187A - Processing liquid for lithographic printing plates - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (A) Industrial Application Field The present invention relates to a method for making a lithographic printing plate that utilizes a silver image as ink receptivity, and particularly a processing composition for enhancing the ink receptivity of a silver image. It is related to.

CB) Prior art and its problems Printing plates using silver halide emulsions that have high sensitivity and can be spectrally sensitized have already been put into practical use in several forms. Among them, as an offset printing plate that uses a silver image to make it receptive to ink.

U.S. Patent No. 3,721.559, U.S. Patent No. 3,490.9
No. 05, Special Publication No. 48-30562, U.S. Patent No. 3゜3
No. 85.701, No. 3.814.603, Special Publication No. 4
4-27242 1% 1982-21602, U.S. Patent No. 3,454.398, U.S. Patent No. 3,764,323, U.S. Pat. be.

Although these printing plate manufacturing methods are roughly divided into several types, they have in common that they make silver receptive to ink.

A lithographic printing plate consists of a lipophilic image area that accepts oil-based ink and a hydrophilic non-image area that does not accept ink, and the non-image area generally consists of a hydrophilic area that receives water. be done.

Therefore, in normal lithographic printing, both water and ink are supplied to the plate surface, and colored ink is selectively received in the image area and water is selectively received in the non-image area, and the ink on the image line is transferred to the plate surface, for example. This is done by transferring it to a substrate such as paper.

In order to obtain good printed matter, the difference in oleophilicity and hydrophilicity between the surface of one drawing area and the background non-printing area must be sufficiently large, and when water and ink are applied, a sufficient amount of ink must be applied to the drawing area. It is necessary that the non-surface line portions receive no ink at all, and it is desirable that this effect lasts for as many prints as possible.

The above-mentioned method for making printing plates using silver halide emulsions is simple, reliable, rapid, can be automated, and has the characteristics of high sensitivity, high resolution, and high image reproducibility. , for example, compared to the actualized 2nd printing plate (28th edition), which is essentially made of dichromate-sensitized hydrophilic colloid and diazo-sensitized organic colloid, it is not possible to print a larger number of sheets. However, there are some shortcomings in terms of printing durability.

Many attempts have been made to date to improve these deficiencies.

Japanese Patent Publication No. 48-29723 discloses that an organic compound having a mercapto group or a thione group can be applied to a transferred silver image to improve its ink receptivity and printing durability. In JP-A-58-127928, a 2,4-dimercapto-6-substituted-1,3,5-triazine compound is
It has been taught that printing durability can be improved compared to organic compounds having 2 mercapto groups.

The present inventors have previously proposed a method that uses an organic compound having two or more mercapto groups to improve printing durability much better than conventional methods.

However, treatment solutions containing organic compounds having two or more mercapto groups or thionic groups have very poor storage stability, and there is a serious problem that the lipophilic ability of the compound deteriorates over time. Ta. Therefore, there is a need for a lipophilic liquid that has improved storage stability without adversely affecting printability.

(C) Purpose of the Invention The purpose of the present invention is to provide a lipophilic liquid composition for a lithographic printing plate that utilizes a silver image as ink receptivity and has improved storage stability without impairing printability. be.

CD) Structure of the Invention The above-mentioned object of the present invention is to provide a processing liquid composition for a lithographic printing plate that utilizes a silver image as ink receptivity and that contains an organic compound having two or more mercapto groups or thione groups. , was achieved by the above-mentioned composition characterized in that it contains an anionic surfactant having a polyoxyethylene group.

The anionic surfactant having a polyoxyethylene group used in the present invention is preferably represented by the following general formula (1).

General formula (1) % formula % (wherein, 几 represents a substituted or unsubstituted alkyl group, alkenyl group, or aryl group having 1 to 30 carbon atoms.

Q is -o--s --coo-1R1-N+, Rt
-N-Co-1R,t-N802- (B1 on the side represents a hydrogen atom or a substituted or unsubstituted alkyl group.) B represents a divalent group such as an alkylene group, an arylene group, or an oxypropylene group. m is 0 or 1 or more -o-po-o
÷B+FEfOCH2CH2鈷Q-Ban (M on the string represents a cation such as a crystalline hydrogen atom, an alkali metal, an alkaline earth metal, ammonium, or a lower alkylamine).

n is the average degree of polymerization of ethylene oxide, and is from 1 to 50, preferably from 2 to 10.

These compounds are disclosed in U.S. Pat. No. 3,026,202, U.S. Pat.
No. 201.252, No. 3,415,649, JP-A-54-98235, JP-B No. 40-23747, British Patent No. 1,178,546, British Patent No. 1,344,987,
U.S. Patent No. 3,264,108, 2,6 Q O, 8
It is described in No. 31, etc.

Specific examples of the anionic surfactant containing polyoxyethylene of the present invention are shown below.

however, (I-2) CHzCHzO is abbreviated as EO.

C5Ht70(EO)2(CH2)480sNa+C1
*Hzso(EO) a (CHx)a BOsNaC
1aH5sO(EO)a(CH2)ssOxNaC12
H2sS(EO)s(CHz)480sNaHs C1tHzxCON(EO)z(CHz)4sOsNa
C9H190(EO)a805K ClaHgsO(EO)aP-ONa Na Representative specific examples of the organic compound having two or more mercapto groups or thione groups used in the present invention are shown below.

General 2 A Compound 21 Compound 22 Compound 23 Compound 24 Compound 25 Compound 26 Compound 28 CH2CH2SH Compound 29 Compound 30 Compound 32 Compound 33 These compounds can be used in photolithography processing solutions such as developing solutions, stop solutions, and fixing solutions, or in insensitive resins. It is also possible to contain one or more of these compounds in each treatment liquid used in printing process steps such as a dampening liquid and a dampening liquid, or to prepare a special treatment liquid for applying these compounds.

The content of these compounds ranges from about 0.01% to about 5% C
weight) concentration range is appropriate.

Anionic compounds having polyoxyethylene groups used in combination with organic compounds having two or more mercapete groups or thione groups are commercially available as anionic surfactants from various manufacturers and can be easily obtained.

The content of this activator is suitably in a concentration range of about 0.1% to about 20 parts (by weight), and preferably in a combination ratio of about 1 to about 100 times (by weight) to the organic compound.

The treatment liquid composition of the present invention containing at least the organic compound and the activator is a weakly acidic to alkaline p
H range is preferable, and any inorganic or organic acid or alkali agent can be contained.

The present invention has the advantage that when an oxidizing agent is used in combination with the above-mentioned organic compound, the printing durability can be further improved. I can do it.

The oxidizing agent used in the present invention is disclosed in Japanese Patent Application Laid-Open No. 55-98753.
(1) Second metal ion: The first metal ion, i.e., excluding the metal ion with the lowest valence, such as Cu'', Au'', Tt.
10-Or”, Cr+6.Mn”Mn+7. Ce+4. R
h'', Pb+4.Pd'', Pd+4. Co"Ir",
Fe”, Ni”, an+4. V”, Bi”, Mo”Mo
+5. Pt”, Ru+4.Te+4.W”, etc.
These metal ions can be used in the form of water-soluble salts such as elogen salts, nitrates, and sulfates, but if they are insoluble or poorly soluble in water, they can be used in water-miscible organic solvents such as methanol, ethanol, ink panol, etc. Alcohols, dimethylformamide, dioxane, acetone, etc. can also be used, and in some cases, organic solvents immiscible with water may also be used.

Halogens: chlorine, bromine, iodine (3) Halogen acids: hypohalous acid 5 For example, potassium hypochlorite, sodium hypoiodite, sodium hypochlorite, etc. Halogen acids, such as sodium chlorate, iodic acid Potassium, sodium bromate, etc., perhalogen acids such as orthoperiodic acid (H5I04), sodium metaperiodate (NaIO4) nato, N-halocarboxylic acid amides such as N-bromoacetamide, N-bromosuccinimide, etc., N- Halosulfonamides, e.g. tj-jN
-chloro-P-) luenesulfonamide (chloramine T
), N-chlorobenzenesulfonamide (chloramine B
), hypohalous acid esters, such as butyl hypochlorous acid, and these can be used in aqueous solutions or water-miscible organic solvents, or in some cases dissolved in water-immiscible solvents. can.

(4) Quinones: P-benzoquinone Particularly preferred are Cu (cupric chloride, copper nitrate, etc.), Au+3 (phosphorous metals, etc.), Tt+3 (
thallium nitrate, etc.), (2r+4 (potassium dichromate, etc.), Mn+7 (potassium permanganate, etc.), Fe” (ferric chloride, ferric sulfate, ferric salt of ethylenediaminetetraacetic acid, etc.) , Ce+5 (Japanese Unexamined Patent Publication No. 1973-
(III) complexes, etc.) Pb+2 (such as palladium chloride) and H1+
It is a second metal ion such as X, Ce+4.1r+M.

The oxidizing agent may be included in the same treatment liquid as the organic compound described above, or may be included in a separate treatment liquid.

It is practically preferable that the amount of the oxidizing agent included in the various processing solutions is from about 1% to the saturation concentration of the oxidizing agent, preferably about 3% or more.

The present invention is applied to a lithographic printing plate that uses a silver image (including a silver halide image) as described above as ink receptivity.

The silver halide emulsion may be present in the printing plate itself or on a separate negative sheet as an iron source for a printing plate sheet having an image-receiving layer by silver diffusion transfer.

The silver halide emulsion may be silver chloride, silver bromide, silver chlorobromide, or any of these containing iodide, and its binder is preferably gelatin, but some or all of the gelatin may be substituted with other colloidal substances. For example, it may be substituted with casein, albumin, polyvinyl alcohol, polyvinyl alcohol-maleic anhydride, cellulose derivative, acrylamide-vinylimidazole copolymer, and the like. Silver halide is 0.5 to 7 in terms of silver nitrate.
ψ, the binder can usually be used in the range of 0.5 to 10.

The silver halide emulsion can be manufactured by a method known in the ordinary photographic industry, and the manufacturing method for use in printing plates is also disclosed in the above-mentioned known patent documents, so please refer to them. be able to.

The lithographic printing plate used in the present invention is generally treated with an alkaline developer after image exposure, followed by plate-making and printing processes such as a neutralizing liquid, a fixing liquid, a desensitizing liquid, an etching liquid, and a dampening liquid, if necessary. liquid is applied. Such developers include common alkaline photographic developers containing a developing agent such as hydroquinone;
Any developer can be used, such as a developer for the silver diffusion transfer method containing hypo or the like, or a highly alkaline developer containing these as an activator.

Among the various developers used in the present invention, for example,
If an organic compound having a mercapto group or a thione group, or a compound having a heterocyclic group having a sulfur atom, which improves the ink-receiving ability of the image area as described in No. 1-486, is contained, the image The difference in lipophilicity and hydrophilicity between the lined area and the non-lined area becomes large.

The composition of the neutralization, fixing, desensitizing, etching, or dampening liquid used in the present invention depends on the purpose and type of plate material, but in general, these processing liquids The above-mentioned mercapto organic compounds, desensitization accelerators, and buffers.

It is preferred to incorporate conventionally known substances such as preservatives, preservatives, and wetting agents to modify processing activity. For example, gum arabic, carboxymethyl cellulose, sodium alginate, vinyl pyrrolidone, vinyl imidazole, copolymer of methyl vinyl ether and maleic anhydride, carboxymethyl starch, ammonium alginate, oxidite cellulose alginate, methyl cellulose, sulfates (sodium sulfate, ammonium sulfate, etc.), sulfites (potassium sulfite, sodium sulfite, etc.), phosphoric acid, nitric acid, nitrous acid, tannins and their salts, polyol compounds having two or more hydroxyl groups (
Polyethylene glycol, propylene glycol, pentaic acid (IJ), t-ol, glycerol, diethylene glycol, hexylene glycol, etc.), organic weak acids (citric acid, succinic acid, tartaric acid, adipic acid, ascorbic acid, propionic acid, etc.), inorganic fine particles (coqidal silica, alumina, etc.), ammonium polyacrylic acid monodichromate, chromium alum, alginate propylene glycol ester, aminopolycarboxylic acid salts (ethylenediaminetetraacetic acid sodium salt, etc.), surfactants, etc. Alternatively, by adding two or more kinds, it is possible to obtain a plate-making and printing processing liquid that more completely satisfies the objectives of the present invention.

In addition, a small amount of a water-miscible organic solvent such as methanol, dimethylformide, or dioxane, or a coloring agent such as phthalocyanine dye, malachite green, or ultramarine may be added, taking into consideration the distinguishable appearance of the liquid.

(E) Examples The present invention will be explained below using examples, but it is of course not limited thereto.

Example 1 A matting layer containing silica particles with an average particle size of 5 μm was provided on one side of a subbed polyester film support, and the opposite side contained carbon black in an amount to give a light reflectance of 3%, Halesin prevention layer*B (adjusted to pH 4.0) containing 20% by weight of silica powder with an average particle size of 7 μm based on photographic gelatin, and silica powder with an average particle size of 7 μm after chemical sensitization. 5 for photographic gelatin.
A spectrally sensitized high-sensitivity silver chloride emulsion layer (adjusted to pH 4.0) was provided in the green-sensitive region containing a proportion of

Is the gelatin of the undercoat layer 3.5f/rr? The gelatin of Emulsion J- was coated at a rate of 0.8 t/rrl, or 1.0 g/rrl of silver nitrate. The undercoat layer and emulsion layer contain formalin as a hardening agent at a ratio of 5.01 to gelatin.
Contains an amount of gelatin. After drying and heating at 40°C for 14 days, JP-A-54-10310 was applied on top of this emulsion layer.
4 Applying the coating liquid described in plate JP631 of Example 2,
Dry and produce a lithographic printing plate. Silver halide emulsion is
4 x 10 mol of rhodium chloride was added per 91 mol of halide during physical ripening, and the average particle size was 0.40.
It was a micron.

The lithographic printing plate master thus obtained was image-exposed using a plate-making camera with an image reversal mechanism, developed with the following developer (working solution) at 30°C for 30 seconds, and then with the following neutralizing solution. Processed.

<Developer> Neutralizing liquid> (Adjusted to pH = 7.8) The printing plate prepared by the above procedure was set in an offset printing machine, and an etch liquid of the following composition was applied all over the plate surface.
Printing was performed using a dampening liquid having the following composition.

Etching liquid〉 Humidifying liquid〉 (The liquid to be used is diluted 10 times with water.) The printing machine is a NiB Dick 350CD (A・B @ Di
The ink receptivity, ease of staining, and printing durability were evaluated using the following methods.

1) Ink acceptance characteristics The number of prints until a print with good image density is obtained, starting from the time when the inked roller comes into contact with the printing plate and paper feeding begins.

2) Evaluation of stains After printing i and ooo sheets, the following three levels were evaluated based on the degree of stains on the printed matter: 9.

O complete (No stains occur.

Δ Partial or light stains × Full-scale light stains 3) Printing durability Continuing to print from 1,000 sheets to so, ooo sheets, depending on the number of prints when ink appears in the silver image area, the following 5 types It was evaluated based on the level.

1 5,000 sheets or less 2 10,000 sheets or less 3 30,000 sheets or less 4 50,000 sheets or less s so, ooo sheets or more On the other hand, after treatment with the neutralizing solution, dry and lipophilize as shown in the table below. Printing and evaluation were performed as described above, except that the entire plate surface was treated with the solution. Furthermore, after aging these lipophilic solutions at 50° C. for 2 weeks, they were plate-made and printed in the same manner as above, and evaluated.

A: Example (1-6) B Sodium di-2-ethylhexyl sulfosuccinate (manufactured by Kako Co., Ltd., Perex 0T-P) C: Polyoxyethylene nonylphenyl ether (manufactured by Nikko Chemicals Co., Ltd., NP-10) The results are shown in Table 1 Shown below. The results of the lipophilic solution after time are shown in the lower row.

Table 1 It can be seen that the lipophilicity of the mercapto compound 18 in the comparative lipophilic liquids I, 1, and 2 has expired over time.

Example 2 A test was conducted using the etchant shown in Table 2 below as the etchant used in Example 1. Only the rigidity resistance is shown in Table 2.

Table-2 (1-2), (1-10), (1-11) and (1-1
Example 1 was repeated using 5). In both cases, the effects of the present invention were similarly confirmed.

Comparative compound S: 3-mercapto-4-7cetamido-5-n-butyl-
1,2,4-) Riazole Example 3 As a surfactant for the lipophilization liquid of Example 1,

Claims (1)

[Claims] A processing liquid for a lithographic printing plate that utilizes a silver image as ink receptivity, characterized by containing an organic compound having one, two or more mercapto groups or thionic groups, and an anionic surfactant having a polyoxyethylene group.