JPH051463B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention relates to a silver salt lithographic printing plate material, and more particularly to a silver salt lithographic printing plate material with improved ink receptivity and printing durability. (Prior Art) Many methods have been known for producing lithographic printing plates using the silver salt diffusion transfer method.
A typical example is U.S. Patent No. 3344741.
The methods described in Japanese Patent Publication No. 16725/1983, and the specifications of Japanese Patent Publication No. 16725/1982 are known. There are also methods described in Japanese Patent Publication Nos. 46-42453 and 48-30562. In the former method, the photographic element having the photosensitive layer and the development nucleus layer, which is the printed image element, are each made up of separate units;
The latter is the technology that integrates it. Also, as another method, US Pat. No. 3,511,656,
There is a method described in the specifications of No. 3557690, etc.
In this method, a photographic element having a photosensitive layer provided as an uppermost layer is diffusely transferred to a lower printed image element, and then the uppermost layer is eluted and peeled off with water to obtain a printing plate. A typical processing solution for a lithographic printing material using a silver salt diffusion transfer method in which a photosensitive silver halide emulsion layer and a physical development nucleus layer are the main constituent layers contains a developing agent, a silver halide solvent, and an alkaline agent. It contains at least These processing solutions are not only oxidized by oxygen in the air, which deteriorates their performance, but also cause fatigue when processing a large amount of the printing materials continuously, resulting in a photograph of the resulting printing materials. It is known to have various undesirable effects on properties. Therefore, one method for eliminating such drawbacks is to include a developing agent in the constituent layers of the lithographic printing plate material in an amount necessary to develop the exposed silver halide, and to remove the developing agent after exposure. Lithographic printing plate materials for so-called activator-type silver salt diffusion transfer processes which can be processed using substantially alkaline-free activated baths are also well known. However, in a lithographic printing plate using such a silver salt diffusion transfer method, it is extremely important to improve the ink receptivity, that is, the ink receptivity, of the silver image area. Therefore, many techniques have been proposed for the purpose of improving the ink receptivity of the silver image area, such as improving the lithographic printing plate itself or improving the processing agent. For example, in a lithographic printing plate having an integrated structure as described above using the silver salt diffusion transfer method, after image exposure, silver salt diffusion transfer development is performed to remove the halogen coated on the side closer to the support. The unexposed silver halide grains of the silver halide emulsion layer accumulate on the physical development nuclei of the physical development nucleus layer coated on the upper side of the silver halide emulsion layer to form a reduced silver image. The greater the proportion of particles serving as development nuclei present and arranged on the surface of the physical development nucleus layer during the formation of this silver image, the easier it is for lipophilic metallic silver to be formed on the surface, resulting in improved ink receptivity and Ink receptivity will be improved. For this reason, it is most preferable that the particles serving as development nuclei in the physical development nucleus layer (for example, metal fine particles or metal sulfide fine particles) are exposed and arranged on the uppermost surface without being buried in the layer as much as possible. Therefore, improved techniques have been proposed to minimize the amount of binder used in the physical development nucleus layer to make it easier to arrange the development nucleus particles on the surface.
16725, 48-30562, and JP-A-56-27151, which uses polyvinyl alcohol with a degree of saponification of 80 to 95% for the physical development nucleus layer. However, in the case of activator type printing plate materials in which a constituent layer contains a developing agent having the above-mentioned merits, serious problems may arise in terms of printing characteristics when the above-mentioned improved technology is applied. It has become clear that a fully satisfactory printing plate material cannot be obtained using only the improved technique described above. The above-mentioned problem is, for example, that depending on the development treatment method of the printing plate material, differences may occur in the ink receptivity and printing durability of the printing plate. In other words, there is a large difference in printing characteristics and printability between static development processing using plate development and stirring development processing using an automatic plate making machine. For example, processing using an automatic plate making machine causes development that significantly deteriorates printing durability. . From this point of view, users of printing plate materials strongly desire the emergence of lithographic printing plate materials that have stable ink receptivity and printing durability, no matter what type of development process is used. Ta. (Object of the Invention) Therefore, the object of the present invention is to provide a silver salt lithographic printing plate material for the silver salt diffusion transfer method, which can always provide stable ink receptivity and printing durability no matter what development method is used. Our goal is to provide the following. (Structure of the Invention) The object of the present invention is to provide a silver halide film having on a support a physical development nucleus layer and a constituent layer containing a developing agent in an amount that enables the exposed silver halide to be developed in an alkaline activation bath. In the silver salt planographic printing plate material for salt diffusion transfer method, the physical development nucleus layer is formed by applying a colloidal solution of a metal or metal sulfide dispersed in an aqueous polyvinyl alcohol solution having a degree of saponification of 96% or more. This can be achieved by forming a layer of silver salt lithographic printing plate material. The invention will now be described in more detail. The silver salt lithographic printing plate material of the present invention (hereinafter referred to as the printing plate material of the present invention) has a photographic element carrying a photosensitive layer and a development nucleus layer serving as a printed image element, each of which is configured as separate units. A photographic element carrying a photosensitive layer on top to a silver image on a lower printed image element is widely included. This also includes a method in which, after diffusion transfer, the uppermost photosensitive layer is eluted and peeled off using water to obtain a printing plate. In the present invention, a lithographic printing plate material having a structure in which an antihalation layer, a silver halide emulsion layer, and a physical development nucleus layer are coated in order from the support side is more preferable. The above-mentioned antihalation layer is a colored layer containing a photographic filter dye, an antihalation dye, a pigment, etc. used in ordinary photographic light-sensitive materials. The antihalation layer in the present invention is
For example, compounds described in the specifications of US Pat. No. 2,274,782, US Pat. No. 2,527,583, US Pat. No. 2,956,879, US Pat. These dyes may be mordanted, if necessary, by the method described in US Pat. No. 3,282,699. Colorants such as pigments (eg, lamp black, carbon black, fast black, ultramarine, malachite green, crystal violet) can also be used as the antihalation layer. In addition, additives that are usually added to emulsions such as antifoggants, matting agents, and surfactants can also be used. The types of photosensitive silver halide emulsions used in the present invention include silver chloride, silver bromide, silver iodide, silver chlorobromide, silver chloroiodobromide, which are generally used in silver halide photographic materials. It is selected from silver bromoiodide and mixtures of two or more thereof. The type of emulsion may be either a negative emulsion or a positive emulsion. For example, the surface of the emulsion may be made refractory to the extent that it is more easily soluble than the silver halide using a photosensitive silver halide and a refractory agent. It may also be a special emulsion of the type described in JP-A-54-48544, which comprises substantially non-photosensitive metal salt particles. These silver halide emulsions can be used as needed.
Chemical sensitization is performed using sulfur sensitizers, selenium sensitizers, noble metal sensitizers, reduction sensitizers, polyalkylene oxide-based sensitizers, and the like. Further, if necessary, spectral sensitization can be carried out using various sensitizing dyes, and fogging can also be prevented by using known stabilizers such as imidazoles, triazoles, and azaindenes. Furthermore, if necessary, hardeners, antistatic agents, antioxidants, preservatives, matting agents, development speed regulators,
A grain quality improver, a surfactant, a thickener, an ultraviolet absorber, etc. can be used. As the binder for the antihalation layer and silver halide emulsion layer, commonly used binders can be used, such as gelatin, gelatin derivatives, polyvinyl alcohol, copolymers of maleic anhydride and vinyl compounds, and ester compounds thereof. etc. can be mentioned. Further, as the hardening agent for the above-mentioned constituent layer, for example, formaldehyde, glutaraldehyde, glyoxal, etc. can be preferably mentioned, and these may be used alone or in combination of two or more kinds, and if necessary, other kinds of hardening agents can be used. May be used together. These hardeners may be added directly or dissolved in water, an organic solvent, etc. to the layer coating solution for the above-mentioned constituent layers, or may be added at the stage of the coating process. According to the present invention, a developing agent is incorporated in the constituent layers of the printing plate material of the present invention in such an amount that the exposed silver halide can be developed in an alkaline activation bath.
In this case, development after exposure can be carried out by activation treatment using an alkaline aqueous solution. The developing agent is used in the silver halide photosensitive layer or its adjacent layer (undercoat layer, intermediate layer or antihalation layer,
It can be contained in a release layer). Incidentally, a developer may naturally be included in the alkali activation bath. Specific compounds for the developer include polyhydroxybenzenes such as hydroquinone, catechol, chlorohydroquinone, pyroganol, bromohydroquinone, isopropylhydroquinone,
toluhydroquinone, methylhydroquinone, 2,3
-dichlorohydroquinone, 2,5-dimethylhydroquinone, 2,3-dibromohydroquinone, 1,
4-dihydroxy-2-acetophenone, 2,5
-dimethylhydroquinone, 4-phenylcatechol, 4-t-butylcatechol, 4-n-butylpyrogallol, 4,5-dibromocatechol,
Included are 2,5-diethylhydroquinone, 2,5-benzoylaminohydroquinone, 4-benzyloxycatechol, 4-n-butoxycatechol, and the like. Among these, hydroquinone and methylhydroquinone are particularly preferably used. Other developing agents include 3-pyrazolidone compounds such as 1-phenyl-3-pyrazolidone, 1-p-tolyl-3-pyrazolidone, and 1-pyrazolidone.
-phenyl-4-methyl-3-pyrazolidone, 1
-Phenyl-4,4-dimethyl-3-pyrazolidone, 1-p-chlorophenyl-3-pyrazolidone, 1-p-methoxyphenyl-3-pyrazolidone, 1-phenyl-2-acetyl-3-pyrazolidone, 1-phenyl -5,5-dimethyl-3-pyrazolidone, 1-o-chlorophenyl-4-methyl-4-ethyl-3-pyrazolidone, 1-m-acetamidophenyl-4,4-diethyl-3-pyrazolidone, 1, 5-diphenyl-3-pyrazolidone, 1-(m-tolyl)-5-phenyl-3-pyrazolidone, 4,4-dihydroxymethyl-1-phenyl-3-pyrazolidone, 4,4-dihydroxymethyl-1-tolyl- 3-pyrazolidone, 4-
Hydroxymethyl-4-methyl-1-phenyl-
3-pyrazolidone, 4-hydroxymethyl-4-
Included are methyl-1-(p-chlorophenyl)-3-pyrazolidone and the like. In addition, as aminophenols, for example, p-
(Methylamino)phenol, p-aminophenol, 2,4-diaminophenol, p-(benzylamino)phenol, 2-methyl-4-aminophenol, 2-hydroxymethyl-4-aminophenol, etc. . The above developing agents can be used alone or in combination. In particular, a combination of a polyhydroxybenzene compound and a 3-pyrazolidone compound is preferred. The amount of the developing agent used in the constituent layers is not uniform, but may be in the range of 0.001 g to 1 g per 1 m ² , and in the case of a silver halide photosensitive layer, it is 0.01 g to 3 g per m 2 .
g/g of silver halide. In addition, in the constituent layers of the printing plate material of the present invention, if necessary, a compound called a complexing agent, which easily forms a soluble silver complex salt with silver halide in the unexposed area, may be included to advantageously facilitate physical development. It can be promoted. Although the layer structure of the printing plate material of the present invention is not specified, it preferably has a physical development nucleus layer on the antihalation layer and silver halide emulsion layer, and according to the present invention, The physical development nucleus layer is characterized in that it is formed by applying a colloidal solution of a metal or metal sulfide dispersed in an aqueous polyvinyl alcohol solution having a degree of saponification of 96% or more. That is, as physical development nuclei of the physical development nucleus layer according to the present invention, for example, antimony, bismuth, cadmium, cobalt, palladium, nickel, gold,
It may be a layer in which known nuclei such as metals such as silver, zinc, etc. and sulfides of these metals are dispersed in a colloidal form, and in detail, the layer may be formed by the silver halide diffusion process (Focal Press, 1972).
2007) The method described on pages 54 to 57 can be applied. In the present invention, as described above, polyvinyl alcohol with a degree of saponification of 96% or more is used as a colloidal binder for colloidally dispersing metals or metal sulfides. In the present invention, the above polyvinyl alcohol may be used alone, but a vinyl compound represented by the following general formula may be used as a reaction product with a copolymer with maleic anhydride. general formula In the formula, R is a hydrogen atom, a methyl group, a methoxy group,
Represents a phenyl group. Among the above substituents, a methoxy group is most preferred, and such a compound is commercially available from Gokyo Sangyo Co., Ltd. under the trade name "Guntolets". The reaction between the above-mentioned gauntlets and polyvinyl alcohol can be easily obtained by dispersing each in water in an arbitrary ratio and heating the mixture to 85° C. or higher while stirring. The above reaction can be stopped by cooling when the desired viscosity is reached, and the pH is adjusted as necessary. The polyvinyl alcohol used in the present invention is available from Kuraray Co., Ltd., Denki Kagaku Kogyo Co., Ltd., Nippon Gosei Kagaku Kogyo Co., Ltd., etc., and has trade names such as "Kuraray Poval,""DenkaPoval," and "Gohsenol," respectively. Although they are commercially available, they are further categorized by product names based on their degree of polymerization, degree of saponification, etc. Generally, polyvinyl alcohol can be synthesized by hydrolysis of polyvinyl acetate, but its properties are largely determined by the number of hydroxyl groups rather than the degree of polymerization, and therefore the degree of saponification is very important. For example, JP-A-56-27151 discloses a method for producing a printing plate material using polyvinyl alcohol having a degree of saponification of 80 to 95% for the physical development nucleus layer of the printing plate material. Polyvinyl alcohol with a low degree of saponification has a high solubility in water, is less likely to form a sol at relatively high concentrations than polyvinyl alcohol with a high degree of saponification, and also has good protective colloidal properties, so it certainly has physical properties. Excellent for producing colloidal solutions of development nuclei. However, according to the research of the present inventors,
In terms of ink receptivity, especially ink receptivity when plate making is performed using an automatic plate making machine, printing plates made using polyvinyl alcohol with a high degree of saponification are far superior. The reason for this is not necessarily clear, but it is thought that the reduction in protective colloidal properties caused by polyvinyl alcohol with a high degree of saponification is rather suitable for arranging physical development nucleus particles on the surface of the printing plate. It is assumed that one of the reasons for this is that polyvinyl alcohol with a high degree of saponification has a high film-forming property, or that the film has low water absorption. In addition, according to the research of the present inventors, in the process of developing printing plates using an automatic plate making machine, a stirring effect is added by the automatic conveyance of the plate material itself, regardless of whether or not the processing solution is stirred. A silver image is more easily formed on the surface by diffusion transfer than by static development. Therefore, the printing plate obtained using an automatic plate-making machine is
Although the initial ink receptivity is good, the image silver tends to peel off easily, making it difficult to obtain sufficient printing durability. However, like the printing plate material of the present invention,
So-called “complete saponification type” with a saponification degree of 96% or more
By using polyvinyl alcohol as a binder for the physical development nucleus layer, the abrasion resistance of the nucleus layer is improved, and furthermore, the hardening effect of the aldehyde hardener can be significantly exerted, so water resistance is also enhanced. It is possible to obtain the unexpected effect of improving printing durability. Examples of the support for the lithographic printing plate in the present invention include baryta paper, polyethylene-coated paper, polypropylene synthetic paper, glass plate, cellulose acetate, cellulose nitrate, polyethylene terephthalate, etc. each subjected to corona discharge treatment, subbing treatment, etc. Polyester film, polyamide film, polypropylene film, polycarbonate film, polystyrene film, or anodized aluminum plate, metal plate, metal foil laminated paper, etc. are included. These supports can be transparent or opaque depending on the purpose of the material. It can also be colored and made transparent using dyes and pigments. The opaque support is typically paper, but it also includes paper made light-shielding with carbon black, dyes, pigments, etc., and plastic films. Furthermore, the back surface of the support can be roughened with a matting agent to make it less slippery. The constituent layers of the printing plate material of the present invention may be coated on the above-mentioned support by any coating method well known in the art, such as dip method, air knife method, Rougeon doctor method, bead coating method, etc. can be used. According to the present invention, it is preferable that a hydrophilic colloid layer other than the physical development nucleus layer is applied by a bead coating method, and after drying, a physical development nucleus layer is applied on this layer by an air knife method. When coating the above-mentioned constituent layers, it is preferable to add a known coating aid to the coating liquid. These application aids include natural products such as saponin,
Anionic or nonionic surfactants such as alkylene oxide type, glycerin type, glycidol type, fluorine type, etc., higher alkylamines, quaternary ammonium salts, pyridine and other heterocycles, cationic surfactants such as phosphonium or sulfonium, Contains anionic surfactants with acidic groups such as carboxylic acids, sulfonic acids, phosphoric acids, sulfuric esters, and phosphoric esters; amphoteric surfactants such as amino acids, aminosulfonic acids, and sulfuric or phosphoric esters of amino alcohols. It will be done. Some examples of surfactant compounds that can be used include U.S. Pat.
No. 2288226, No. 2739891, No. 2739891, No. 2288226, No. 2739891, No.
No. 3068101, No. 3158484, No. 3201253, No. 3210191, No. 3294540, No. 3415649,
Same No. 3441413, Same No. 3442654, Same No. 3475774,
British Patent No. 3545574, British Patent No. 1077317, British Patent No.
1198450, Ryohei Oda et al., "Synthesis of surfactants and their applications" (Maki Shoten, 1964)
(2013) and Surf S Active Agent by A. W. Berry (Interscience Publishing, Inc., 1958), JP
It is described in "Encyclopedia of Active Agents Volume 2" by John Sisley (Chemical Publishing Company, 1964). Hereinafter, the present invention will be described in more detail with reference to Examples. Example 1 Coating solutions having the following compositions were prepared as an antihalation layer and a silver halide emulsion layer. (Composition of anti-halation layer coating liquid) [Liquid A] Carbon black (4% solids dispersion) 150g Gelatin 45g Water 400ml [Liquid B] Saponin (10% aqueous solution) 10ml Matting agent (silica, Thyroid 308) 10g Water 300ml [Liquid C] Dimaison 1.5g Hydroquinone 7.0g Methanol 40.0ml Make up to 100ml with water. [Liquid D] Formalin 35% solution 6.0ml Make up to 100ml with water. Mix the above [Liquid A], [Liquid B] and [Liquid C] in sequence, adjust the pH to 4.5, and immediately before applying [Liquid D]
Add inline. (Preparation of silver halide emulsion coating solution) A pure silver chloride emulsion prepared by a conventional mixing method was chemically ripened using a chemical sensitizer, and ortho-sensitized using an optical sensitizer. After aging, 4-hydroxy-6-methyl-1,3,
Appropriate amounts of the 3a,7-tetrazaindene compound and potassium bromide were added. Further, an appropriate amount of sodium isoamyl-n-decylsulfosuccinate as a coating aid and 0.2 g of fine silica powder (Thyroid 308) as a matting agent per 1 g of gelatin were added, and the pH was adjusted to 4.5. Note that the concentration of gelatin was 6%. The antihalation coating solution obtained above and the coating solution for silver halide emulsion obtained above were each placed on a polyethylene-coated paper support having a thickness of 135 g/m ² with an antihalation layer as a supporting body. A silver halide emulsion layer was applied as an upper layer to a nearby layer, that is, a lower layer, and the layers were simultaneously coated in multiple layers by a bead coating method and dried. The obtained two-layer coated sample was subjected to a seasoning treatment (left for 3 days at 40°C and RH45%), and then a physical development nucleus layer coating solution with the following composition was applied to the upper layer using the air knife method, and then dried. A printing plate material was prepared. (Coating liquid composition for physical development nucleus layer) [Liquid A] Binder (see below) 0.13g Water 750ml [Liquid B] HAuCl ₄・4H ₂ O 0.8g Water 50ml [Liquid C] NaBH ₄ 0.4g Water 200ml Above [Liquid A] ] and [Liquid B] were mixed at room temperature, and then [Liquid C] was added and reduced with strong stirring to prepare a colloidal gold solution. The following four types of polyvinyl alcohols were used as the binder. (1) Kuraray Poval pVA-215 (saponification degree 88%) (2) Kuraray Poval pVA-215 and Gantolets reaction solution (3) Kuraray Poval pVA-110 (saponification degree 98.5%) (4) Kuraray Poval pVA- Reaction product of 110 and Gantrez An appropriate amount of sodium isoaluminium-n-decylsulfosuccinate was added to the above gold colloid solution as a coating aid. The prepared printing plate material was subjected to image exposure, development, and stabilization treatment using a static development and automatic plate making machine (IPA-300, manufactured by ITEC Corporation). The composition of the treatment liquid used is as follows. (Alkaline activation liquid) Caustic potash 25g Anhydrous sodium sulfite 50g Sodium thiosulfate 3g 2-Mercapto-5-methyl-oxadiazole 0.1g Make up to 1000ml with water. (Stabilization bath) Add citric acid and sodium citrate water to make 1000ml. The treated printing plates were printed using an offset printing machine (Gestettner 200 manufactured by Gestettner) and the results are shown in Table 1 below. The ink receptivity in the table is determined by bringing the water roller into contact with the printing plate, supplying sufficient water, and then starting paper feeding first before bringing the ink roller into contact with the printing plate to obtain good printed matter with high image density. The evaluation was based on the number of sheets printed until the . ◎: Less than 10 sheets ○: 10 sheets or more and less than 20 sheets △: 20 sheets or more and less than 50 sheets Printing durability was evaluated by continuously printing 5000 sheets. ◎: There is no decrease in image density and no small dots. ○: A decrease in image density and some small dots are observed. △: Decreased image density and small dots are quite noticeable.

[Liquid A]

Binder 0.2g Water 434ml [Liquid B] pdCl ₂ 0.7g 1N-HCl 5.3ml Water 150ml Heat at 50°C for 10 minutes, dissolve, and then cool. [Liquid C] 1.4 g Na ₂ S・9H ₂ O 400 ml Water After mixing the above [Liquid A] and [Liquid B], add [Liquid C] while stirring at 15°C. After 30 minutes of reaction, the product was purified by ultrafiltration. The following two types of polyvinyl alcohols were used as the binder. (1) Denka Poval B-20 (saponification degree 87-89%)
Reactant with Gantolets (2) Denkapoval K-20 (saponification degree 97.5-98.5
%) and Gantolets An appropriate amount of sodium isoamyl-n-decylsulfosuccinate was added as a coating aid to the above-mentioned coating solution for the physical development nucleus layer. The prepared printing plate samples were treated in the same manner as in Example 1, and the results obtained are shown in Table 2 below.

[Table] From what the above table shows, in the sample of the present invention using polyvinyl alcohol with a degree of saponification of 96% or more according to the present invention as the binder of the physical development nucleus layer, even if the type of physical development nucleus changes. It was also found that superior printing characteristics could be obtained compared to the comparative samples in both static development and development using an automatic plate making machine. (Effects of the Invention) The silver salt lithographic printing plate material according to the present invention, in which the binder of the physical development nucleus layer is polyvinyl alcohol with a degree of saponification of 96% or more, has excellent ink properties during static development and processing with an automatic plate making machine. It is possible to obtain ink receptivity and printing resistance.

Claims (1)

[Claims] 1 Silver salt lithographic printing for silver salt diffusion transfer method having on a support a physical development nucleus layer and a constituent layer containing a developing agent in an amount that enables the exposed silver halide to be developed in an alkaline activation bath. In the plate material, the physical development nucleus layer is a layer formed by applying a colloidal solution of a metal or metal sulfide dispersed in an aqueous polyvinyl alcohol solution having a degree of saponification of 96% or more. Silver salt lithographic printing plate material.