JPH0713332A - Treating liquid for lithographic printing plate - Google Patents

Abstract

PURPOSE:To provide the treating liquid which reduces the dirt of a substrate and improves the printing durability without deteriorating the ink acceptance performance, by carrying out the development processes for a lithgraph printing press applying the silver compex salt diffusion copying method, and carrying out the treatment by the treating liquid containing the water-soluble polymer. CONSTITUTION:The treating liquid for printing press which contains the water- soluble polymer represented by the formula is used as the treating liquid used after the development processes for a lithograph printing press applying the silver complex slat diffusion copying method. In the formula, each of R<1>-R<3> may be the same or different, and each is a hydrogen atom or a lower alkyl group. A is a substituted amino group. B is a neterocyclic group having the affinity with the precious metal ion. Each of l, m, n, and z is a molar %, and l is 0-97, m is 1-95, n is 0-60, and z is 0.1-20mol%. Further, the weight average moleculal weight in the polymer is 1,000-200,000.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lithographic printing plate that uses a silver image formed by applying a silver complex salt diffusion transfer method as an ink accepting property, and is applied after development to prevent background stains in non-image areas. Processing liquid.

[0002]

2. Description of the Related Art A high-sensitivity lithographic printing plate which can be spectrally sensitized by a lithographic printing plate using a silver complex salt diffusion transfer method (DTR method) is disclosed in US Pat. Nos. 3,721,559 and 3,490,90.
5, Japanese Patent Publication No. 48-30562, U.S. Pat. No. 3,81
4,603, JP-B-44-27242, JP-A-53.
-21602, U.S. Pat. Nos. 3,454,398, 3,764,323, 3,099,209,
It is reported in JP-A-53-9603. These printing plates are common in that they make the image silver ink-accepting, although there are differences in processing and manufacturing methods.

A lithographic printing plate is composed of an oleophilic image-forming portion that receives oil-based ink and a hydrophilic non-image-forming portion that does not receive ink. In ordinary lithographic printing, both water and ink are supplied to the plate surface, the image area selectively receives coloring ink, and the non-image area selectively receives water. It is made by transferring to a substrate such as.

In order to produce a good printed matter, the difference in lipophilicity and hydrophilicity between the image area and the non-image area is sufficiently large that the image area receives a sufficient amount of ink, while the non-image area is It is necessary not to add ink at all, and it is necessary that the effect lasts as long as possible. For this purpose, various desensitizing methods have been investigated. It is generally known that printing stains in lithographic printing are caused not by a single cause but by overlapping various factors. Factors include the properties peculiar to the plate material, printing ink, fountain solution, printing paper, and the like. Furthermore, it is affected by the condition of the printing press, environmental conditions such as temperature and humidity at the time of printing, and it is necessary to properly maintain those conditions and the environment at the time of printing, and much effort is devoted to this. . Therefore, from a practical point of view,
There is a demand for a plate-making material that can be printed in as wide a condition as possible.

The direct lithographic printing plate using the above-mentioned silver halide emulsion is simple, quick, can be automated, and has the characteristics of high sensitivity, high resolution and high image reproducibility. It is a match. On the other hand,
For example, it has a drawback that background stains are more likely to occur in the non-image area as compared with a PS plate or the like. Further, by storing the lithographic printing plate for a long time from the production to the plate making, the ink acceptability is deteriorated and scumming occurs, the tolerance to various commercially available inks is narrow, and the printing is long. There is also a drawback that scumming easily occurs during running, and further improvement is desired.

Many attempts have been made to overcome these drawbacks. The inventors of the present invention repeated the various tests on the printing stain of the lithographic printing plate using the silver complex salt diffusion transfer method at the starting point of the present invention, and as a result, reached the following conclusions. The first cause of the stain is the acceptability of the ink by the colloidal heavy metal or heavy metal sulfide used as the physical development nuclei. The second reason is that the ink is received by the metallic silver particles in the non-image area which are generated as fog during diffusion transfer. Further, hydrophilic polymers such as gelatin, gum arabic, cellulose, albumin, sodium alginate, and various natural polymers such as starch are applied to the lithographic printing plate after the development treatment to give some hydrophilicity to the plate surface. Although it was possible to improve the property, there was a drawback that the ink acceptability was remarkably reduced due to the improvement of the hydrophilicity of the entire plate surface.

[0007]

The object of the present invention is to develop a lithographic printing plate using the silver complex salt diffusion transfer method after development and then treat with a treatment solution containing a water-soluble polymer. The purpose of the present invention is to provide a processing liquid which has good ink-carrying properties, prevents background stains, and improves printing durability.

[0008]

The above object of the present invention is to provide a water-soluble polymer represented by the following chemical formula 2 in a processing liquid used in a plate making process of a lithographic printing plate using a silver complex salt diffusion transfer method.
Was achieved by adding

[0009]

[Chemical 2]

In the formula, R ^{1 to} R ³ may be the same or different and each is a hydrogen atom or a lower alkyl group. A
Is a substituted amino group. B is a heterocyclic group having an affinity for a noble metal ion. l, m, n, and z are mol% and l
Is 0 to 97, m is 1 to 95, n is 0 to 60, and z is 0.1.
Is about 20 mol%. The weight average molecular weight of the polymer is 1,000 to 200,000.

In the silver complex salt diffusion transfer method (DTR), a metal such as silver, palladium, nickel or a sulfide of a metal is used as a physical development nucleus. The heterocyclic residue in the water-soluble polymer molecule makes a stable bond with the metal or metal ion. The composition ratio of the substituent having an affinity for the metals depends on the kind of the substituent, but is generally about 0.5 mol% to about 40 mol%, more preferably 0.5 mol% to 10 mol%. Mol%
Is in between. If the content of the substituent is too high, the hydrophilic effect is too strong and the ink acceptability of the silver image is lowered. The average molecular weight of the water-soluble polymer used in the present invention is about 1,0.
Between 0 and about 200,000 and between about 30,000 and
About 150,000 is good. Further, the content of the water-soluble polymer is preferably in the range of 0.5 to 10%, more preferably in the range of 1 to 5. If it is out of this range, the effect of preventing stains in printing is lowered, or the above-mentioned defects are likely to occur.

Specific examples of the water-soluble polymer used in the present invention are shown below.

[0013]

[Chemical 3]

[0014]

[Chemical 4]

[0015]

[Chemical 5]

[0016]

[Chemical 6]

[0017]

[Chemical 7]

[0018]

[Chemical 8]

[0019]

[Chemical 9]

[0020]

[Chemical 10]

[0021]

[Chemical 11]

[0022]

[Chemical 12]

[0023]

[Chemical 13]

[0024]

[Chemical 14]

The water-soluble polymer used in the present invention can be synthesized by a conventional method. That is, a polymerization initiator is added to a solution of a mixture of two or three vinyl monomers and heated, or a liquid containing the polymerization initiator is kept at a high temperature,
It is obtained by dropping the monomer mixture therein. A desired amount of the water-soluble polymer can be obtained by adding a calculated amount of formalin to the alkali aqueous solution of the water-soluble polymer thus obtained and methylating the amide group.
Many monomers that can be used for vinyl polymerization are known (for example, Synthetic Polymer II published by Asakura Shoten).

The processing liquid of the present invention is a silver complex salt diffusion transfer method (D
It is used for a lithographic printing plate using the TR method) and further increases the difference between lipophilicity and hydrophilicity to reduce print stains.

The direct printing plate to which the present invention is applied is
The silver halide emulsion may be in the printing original plate itself,
It may be on a negative sheet different from the image receiving layer. The type of silver halide emulsion may be any of silver chloride, silver bromide, silver chlorobromide, and those containing silver iodide. The binder is preferably gelatin, but part or all of gelatin may be used. It may be substituted with other colloidoid substances such as casein, albumin, polyvinyl alcohol, polyvinyl alcohol-maleic anhydride ester, cellulose derivative, acrylamide-vinyl imidazole copolymer and the like. The silver halide is 0.5 to 0.5 in terms of silver nitrate.
The binder can be used in the range of 0.5 to 30 g / m < ² > and 10 g / m < ² >.

The silver halide emulsion can be produced by a known method, and a production method for use in a printing plate is also disclosed in the aforementioned patent documents.

Physical development nuclei are contained in the positive layer in the negative / positive type double-layered product and in the upper part of the emulsion layer in the single-sided product. Physical development nuclei with a surface layer include fine particles of metal colloids such as silver, antimony, bismuth, cadmium, cobalt, lead, nickel, palladium, rhodium, gold and platinum, and sulfides, polysulfides and selenides of these metals. , Or a mixture thereof. The physical development nucleus may or may not have a hydrophilic binder, but gelatin, starch, dialdehyde starch, carboxymethyl cellulose, gum arabic, sodium alginate, hydroxyethyl cellulose, polystyrene sulfonic acid, vinyl A copolymer of imidazole and acrylamide, a hydrophilic polymer such as polyvinyl alcohol, or an oligomer thereof can be contained, and the content thereof is preferably 0.5 g / m ² or less. Further, in the physical development nucleus layer, hydroquinone, methylhydroquinone,
A developing agent such as catechol and a known hardener such as formalin may be contained.

Each of the coating layers such as the undercoat layer, the silver halide emulsion layer and the physical development nucleus layer may contain some of an anion, a cation or a neutral surfactant as a coating aid, Further, it may contain an antifoggant, a matting agent, a thickening agent, an antistatic agent and the like.

As the support for the lithographic printing plate used in the present invention, paper or synthetic or semi-synthetic polymer film, a metal plate of aluminum, iron or the like can be used as long as it can withstand lithographic printing. The surface of the support may be coated on one side or both sides with one or more polymer films or metal thin films. The surface of these supports can be surface-treated in order to improve the adhesion with the coating layer.

Particularly preferably used supports are paper or polyester film whose both surfaces or one surface is coated with a polyolefin polymer, polyester film whose surface has been hydrophilized, and aluminum plate which has been surface-treated. These supports may contain pigments for preventing halation and solid fine particles for improving surface properties.
The support may also be light transmissive so that backside exposure is possible.

The lithographic printing plate used in the present invention is treated with an alkali developing solution after imagewise exposure, and subsequently, if necessary, a plate-making and printing treatment solution such as a neutralizing solution, an etching solution and a moistening solution. As such a developing solution, an ordinary photographic alkaline developing solution containing a developing agent typified by hydroquinone, a developing solution for silver complex salt diffusion transfer method containing hypo, etc. can be used, and the developing agent is contained in the photosensitive material itself. In this case, a single alkaline solution may be used.

Various studies have been conducted on the composition of neutralizing, fixing, etching, dampening liquid, etc. used in the present invention depending on the purpose and the type of plate material. Generally, it is preferable to modify the processing activity by a combination of a mercapto organic compound, a desensitizing accelerator, a buffer, a preservative, a preservative, a wetting agent and the like. For example, gum arabic, carboxymethyl cellulose, sodium alginate, vinylpyrrolidone, vinyl imidazole, a copolymer of methyl vinyl ether and maleic anhydride, carboxymethyl starch, ammonium alginate, oxydide cellulose alginate, Methyl cellulose, sulfates (sodium sulfate, ammonium sulfate, etc.), sulfites (potassium sulfite, sodium sulfite, etc.), phosphoric acid, nitric acid, tannic acid tannic acid and salts thereof, and polyol compounds having two or more hydroxy groups. (Polyethylene glycol, propylene glycol, pentaerythritol, 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 (colloidal silica,
Alumina, etc.), polyacrylic acid, ammonium dichromate, chromium alum, propylene glycol alginate, aminopolycarboxylic acid salt (ethylenediaminetetraacetic acid sodium salt, etc.), surfactant, etc. As a result, a plate-making and printing treatment liquid that completely satisfies the object of the present invention can be obtained. In addition to this, phthalocyanine dyes, malachite green, ultramarine and the like may be added in trace amounts in consideration of the distinctive appearance of water-miscible organic solvents and liquids such as methanol, dimethylformamide and dioxane. I can.

[0035]

EXAMPLES The present invention will be described below with reference to examples, but the present invention is not limited thereto.

Example 1 A polyester film support having an undercoating treatment of 135 g / m ² was provided with a matting layer containing silica particles having an average particle size of 5 μ on one surface, and the light reflectance was 3% on the opposite surface. Chemically sensitized with an anti-halation undercoat layer (adjusted to pH 4.0) containing 20% by weight of silica powder having an average particle size of 7 μm with respect to photographic gelatin. After that, a high-sensitivity silver chloride emulsion layer (adjusted to pH 4.0) spectrally sensitized in the green-sensitive region containing 5% by weight of silica powder having an average particle size of 7 μm with respect to photographic gelatin was provided. The gelatin of the undercoat layer was 3.5 g / m ² , the gelatin of the emulsion layer was 0.8 g / m ² , and the silver halide equivalent to silver nitrate was 1.0 g / m ² .

The subbing layer and the emulsion layer contain formalin as a hardening agent in an amount of 5.0 mg / g gelatin based on gelatin. After drying, after heating at 40 ° C. for 14 minutes, the core coating solution described in Plate No. 31 of Example 54 of JP-A-54-103104 is applied onto this emulsion layer and dried to produce a lithographic printing plate. . 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.
The lithographic printing plate precursor thus obtained was image-exposed with a plate-making camera having an image reversal mechanism and developed with the following developer (use solution) at 30 ° C. for 30 seconds.

Developer sodium hydroxide 24 g potassium hydroxide 8 g anhydrous sodium sulfite 50 g 3-mercapto-4-acetamido-5-n-heptyl-1,2,4-triazol 0.15 g 2-mercaptobenzoic acid 0 1 g 2-methyl-2-amino-1-propanol 30 g uracil 0.2 g Water is added to make the total volume 1 liter. After the development processing, the original plate is passed between two squeezing rollers to remove excess developer, and immediately treated with a neutralizing solution having the following composition at 25 ° C. for 20 seconds, and squeezing rollers are used to remove excess. Was removed and dried at room temperature.

Neutralizing solution Ethylene glycol 5 g Colloidal silica (20% solution) 1 g Anhydrous sodium sulfite 10 g Sodium diphosphate 35 g Water is added to make a total volume of 1 liter. The planographic printing plate prepared by the above operation was set in an offset printing machine, an etchant having the following composition was applied all over the plate surface, 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 (use liquid is diluted 10 times with water) Water 300 ml Succinic acid 6 g Sodium sulphate 25 g Ethylene glycol 100 g Colloidal silica (20% liquid) 28 g Water 2 liters And

The printing machine is an AB-Dick 350CD.
(Trademark of offset printing machine manufactured by AB Dick Co., Ltd.) was used, and the ink receiving characteristics, background stain and printing durability were evaluated by the following methods. 1) Ink acceptance property: The number of printed sheets until a printed matter is obtained with good image density by starting paper feeding at the same time when an inking roller is brought into contact with the plate surface. 2) Evaluation of background stain: 1,000 sheets were printed, and the degree of background stain of the printed matter was evaluated according to the following five criteria. 5 No background stains 4 Partial light background stains 3 Overall light background stains 2 Overall dark background stains 1 Dark background stains not suitable for use 3) Printing durability: 1,000 sheets or more 50,000 Printing was continued up to the number of sheets, and the number of printed sheets when the ink bleeding in the silver image area was printed was evaluated according to the following four criteria. A 50,000 sheets or more B 25,000 sheets C 10,000 sheets D 5,000 sheets or less

The printing plate obtained with the above neutralizing solution is 1,000.
In contrast to the case where scumming occurred up to the number of sheets, a treatment liquid containing the following composition in place of the neutralization liquid, containing the water-soluble polymers 3 to 5 of the present invention in a solid content concentration of 3%. The printing plates obtained in B to J did not cause scumming even with 1,000 sheets.
The printing results of the water-soluble polymer used in Example 1 determined by the above criteria are shown in Table 1.

Lithographic printing plate treatment liquid Water 900 g Anhydrous sodium sulfite 10 g Dibasic sodium phosphate 35 g Water-soluble copolymer polymer 30 g Water is added to make 1 liter.

The following chemical formulas 15 and 16 were used as comparative water-soluble polymers.

[0046]

[Chemical 15]

[0047]

[Chemical 16]

[0048]

[Table 1]

From the results shown in Table 1, the water-soluble polymer of the present invention was used.
It was confirmed that Chemical Formulas 3 to 5 were excellent in printing characteristics, especially water retention property, as compared with Comparative Polymers 15 and 16.

Example 2 Water-soluble polymer of the present invention used in Example 1
Instead of the above, lithographic printing plate processing liquids a to i containing the water-soluble polymers of Chemical Formulas 6 to 8 of the present invention were prepared and subjected to plate-making treatment in the same manner as in Example 1. The printing results are shown in Table 2.

[0051]

[Table 2]

From the results shown in Table 2, the water-soluble polymer of the present invention was used.
It was confirmed that Chemical Formulas 3 to 5 were excellent in printing characteristics, especially water retention property, as compared with Comparative Polymers 15 and 16.

Example 3 Water-soluble polymer of the present invention used in Example 1
Instead of the above, lithographic printing plate processing liquids 1 to 9 containing the water-soluble polymers 9 to 11 of the present invention were prepared and subjected to plate making in the same manner as in Example 1. The printing results are shown in Table 3.

[0054]

[Table 3]

From the results shown in Table 3, it was confirmed that the water-soluble polymers 9 to 11 of the present invention were excellent in printing characteristics, especially water retention, as compared with the comparative polymers 15 and 16.

Example 4 Water-soluble polymer 3 to 5 of the present invention used in Example 1
Instead of the above, lithographic printing plate processing liquids 10 to 18 containing the water-soluble polymers 12 to 14 of the present invention were prepared, and the plate-making treatment was carried out in the same manner as in Example 1. The printing results are shown in Table 4.

[0057]

[Table 4]

From the results shown in Table 4, it was confirmed that the water-soluble polymers 12 to 14 of the present invention were excellent in various printing characteristics, particularly water retention, as compared with the comparative polymers 15 and 16.

[0059]

According to the present invention, after development processing in the plate making process of a lithographic printing plate applying the silver complex salt diffusion transfer method, it is treated with a lithographic printing plate processing solution containing the water-soluble polymer of the present invention. By doing so, there was no background stain, the ink acceptability did not deteriorate, and the printing durability was further improved, and the deterioration of the printing performance due to storage could be improved.

Claims (1)

[Claims] 1. A lithographic printing plate characterized by containing a water-soluble polymer shown in Chemical formula 1 in a processing liquid after development processing in a plate making process of a lithographic printing material to which a silver complex salt diffusion transfer method is applied. Processing liquid. [Chemical 1] In the formula, R ^{1 to} R ³ may be the same or different and each is a hydrogen atom or a lower alkyl group. A is a substituted amino group. B is a heterocyclic group having an affinity for a noble metal ion. l, m, n and z are mol%, 1 is 0 to 97,
m is 1 to 95, n is 0 to 60, z is 0.1 to 20 mol%
Is. The weight average molecular weight of the polymer is 1,000 to 2
It is 0,000.