JPH0749570A - Planographic printing plate - Google Patents

Abstract

PURPOSE:To remarkably improve the ink and water retentivity of a planographic printing material applying a silver complex salt diffusion transfer process and to suppress the deterioration of the printing performance due to storage. CONSTITUTION:In a planographic printing material having at least a silver halide emulsion layer and a physical developing nucleus layer on the substrate and applying a silver complex salt diffusion transfer process, at least one of monosaccharides and oligosaccharides is contained in the physical developing nucleus layer and/or a later adjacent to it.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a lithographic printing material to which a silver complex salt diffusion transfer method is applied.

[0002]

2. Description of the Related Art A lithographic printing plate is composed of an oleophilic image-forming portion that accepts oil-based ink and an oil-repellent non-image-forming portion that does not receive ink. Generally, the non-image-forming portion is hydrophilic to receive water. It is composed of sex parts. In ordinary lithographic printing, both water and ink are supplied to the plate surface, the image area selectively receives the coloring ink, and the non-image area selectively receives water, and the ink on the image area, such as paper Printing is performed by transferring it to a printing medium.

Therefore, in order to obtain a good printed matter, the difference in lipophilicity and hydrophilicity between the image area and the non-image area is sufficiently large, and the image area is sufficient when water and ink are supplied to the plate surface. It is necessary to accept a certain amount of ink and not to accept ink in the non-image area.

A lithographic printing plate using a silver complex salt diffusion transfer method (DTR method), particularly a lithographic printing plate having a physical development nucleus layer on a silver halide emulsion layer is described in, for example, US Pat. No. 3,72.
No. 8,114, No. 4,134,769, No. 4,1
No. 60,670, No. 4,336,321, No. 4,
No. 501,811, No. 4,510,228, No. 4,621,041 and the like. The exposed silver halide crystals cause chemical development by DTR development to give a black color. It becomes silver and forms a hydrophilic non-image area, while unexposed silver halide crystals become a silver salt complex by the silver salt complexing agent in the developing solution and diffuse to the physical development nucleus layer on the surface to form nuclei. In the presence of the above, physical development is caused to form an image area mainly composed of ink-receptive physically developed silver.

As described above, in the planographic printing plate, gelatin-
Since the silver image deposited on the physical development nucleus layer on the silver halide emulsion layer is used as the ink-receptive image area, the image area is larger than that of a general lithographic printing plate (eg PS plate). There is a defect that the resistance to mechanical abrasion of the image part is insufficient, the image part is missing, and the ink receiving property of the image part is gradually lost.

In order to overcome this drawback, if the hardness of gelatin is increased or the amount of physical development nuclei is increased, scumming occurs and the printing durability of the lithographic printing plate remarkably decreases.
Further, when the planographic printing plate is manufactured and stored for a long period of time from the time when the plate is made, there are drawbacks such that scumming occurs and the ink receptivity deteriorates.

Furthermore, if the hardness of gelatin is increased or the amount of physical development nuclei is increased, uneven coating properties of the physical development nuclei layer frequently occur, and printing durability is seen in the unevenness. Dirt,
The effects on ink deposits and ink deposits are seen, and improvements are desired.

To improve water retention, Japanese Patent Application No. 3-6
No. 5545, it was proposed to include pullulan in the physical development nucleus layer or / and the layer adjacent thereto.
The level of improvement effect was not enough. Also, it cannot be said that the ink-repellency is sufficiently good.

[0009]

SUMMARY OF THE INVENTION An object of the present invention is to provide a lithographic printing plate using a silver complex salt diffusion transfer method, which has improved ink transfer and water retention. Another object of the present invention is to provide a lithographic printing plate using a silver complex salt diffusion transfer method which is stable in printing durability, ink buildup and storage stability.

[0010]

The above object of the present invention is to provide a physical development nucleus layer or / or a lithographic printing plate having at least a silver halide emulsion layer and a physical development nucleus layer on a support.
And at least one monosaccharide and oligosaccharide in the adjacent layer
It was achieved by including one.

The monosaccharides or oligosaccharides used in the present invention can be obtained from Hayashibara Shoji Co., Ltd. and are selected from maltose products, oligo products, sugar alcohol products, etc., both monosaccharides and oligosaccharides. Belong to.

The monosaccharides and oligosaccharides of the present invention are chain-like polyhydric alcohols containing one carbonyl group. Most simple sugars contain one carbonyl group and two alcohol groups, but naturally-occurring sugars all have Beilsteins Handbuch der because they have the ability to form a half-acetal bond in the molecule. org.Chemie, B
In books such as d.XXXI Kohlenhydrate (1938), only those containing 4 or more oxygen atoms are treated as monosaccharides. Oligosaccharides are sugars to which 2 to 6 molecules of monosaccharides are bound. The monosaccharides are bound to ether type by leaving an oxygen atom, and hydrolyzed into the component monosaccharides.
Those that are hydrolyzed into two molecules of monosaccharides, such as maltose, lactose, and saccharose, are called disaccharides, those that divide into three molecules of monosaccharides, such as raffinose, are called trisaccharides, and in the present invention, monosaccharides excluding polysaccharides. And oligosaccharides.

The monosaccharides and oligosaccharides of the present invention are disclosed in JP-A-4-2.
Since it has a low molecular weight with respect to pullulan (polysaccharide) filed in 77747, it has the characteristics that when it is used in the physical development nucleus layer, its permeability is improved, its coatability is improved, and ink transfer in printing is improved. . There is also an advantage that it does not thicken when used in the adjacent gelatin layer.

The monosaccharides and oligosaccharides of the present invention may be used in combination with a water-soluble polymer used in the physical development nucleus layer described later, such as carboxymethyl cellulose, gum arabic, sodium alginate, a copolymer of vinylimidazole and acrylamide. As for the effects of monosaccharides and oligosaccharides, Japanese Patent Application No. 4-271698 proposes to use a combination of pullulan and an N-methylol compound. However, the monosaccharides and oligosaccharides of the present invention have the same N-methylol as pullulan. Water retention can be further improved by using the compound in combination.

On the other hand, in Japanese Patent Application No. 5-18964,
A combination of a methylolated product of acrylic amide and a water-soluble polysaccharide has been proposed, but the monosaccharides and oligosaccharides of the present invention can be used to further improve the water retention by combined use with a methylolated product of acrylic amide.

The content of the monosaccharide or oligosaccharide used in the present invention is preferably 500 mg / m ² or less, more preferably ^{2 to} 100 mg / m ² . There is no particular limitation on the method of incorporating the monosaccharide or oligosaccharide into the constituent layer, and the monosaccharide or the oligosaccharide is contained in the physical development nucleus layer or / and its adjacent layer, and it may be added before or after coating the physical development nucleus. From the viewpoint of stability of quality and ease of production, the method of applying together with the physical development nuclei is most advantageous, and it is rational to add it at the time of producing the coating solution.

The lithographic printing plate which is the object of the present invention contains gelatin, and its content may be an undercoat layer, an emulsion layer or a physical development nucleus layer. These gelatin contents can be hardened with a gelatin hardener.
Examples of gelatin hardeners include inorganic compounds such as chromium alum, aldehydes such as formalin, glyoxal, malealdehyde and glutaraldehyde, N-methylol compounds such as urea and ethyleneurea, mucochloric acid, and 2,3-dihydroxy-. Aldehydes such as 1,4-dioxane, 2,4-dichloro-6-hydroxy-S
A compound having an active halogen such as a triazine salt or a 2,4-dihydroxy-6-chloro-triazine salt,
Divinyl sulfone, divinyl ketone, N, N, N-triacroylhexahydrotriazine, compounds having two or more ethyleneimino groups or epoxy groups which are active three-membered rings in the molecule, and as a polymer hardener One or more of various compounds such as dialdehyde starch can be used.

The hardener can be added to all layers or to some or only one layer.
Of course, the diffusible hardener can be added to only one layer in the case of simultaneous coating of two layers. As an addition method, it may be added at the time of emulsion production or in-line at the time of coating.

Gelatin in the gelatin-containing layer of the present invention comprises a part of water-soluble gelatin, starch, dextrin, albumin, sodium alginate, hydroxyethyl cellulose, gum arabic, polyvinyl alcohol, polyvinylpyrrolidone, carboxymethylcellulose, polyacrylamide, styrene. It may be substituted with one or more hydrophilic polymers such as maleic anhydride copolymer and polyvinyl methyl ether-maleic anhydride copolymer. Further, an aqueous vinyl polymer dispersion (latex) can be added to the gelatin layer.

The polymeric binder of the subbing layer is generally 0.5.
It is preferably from 1 to 6 g / m ^2, more preferably from 10 to 10 g / m ² .
The undercoat layer may contain a pigment such as carbon black, a dye or the like for the purpose of preventing halation, and may also contain solid powder (for example, silica particles) having an average particle diameter of 2 to 10 microns for improving printing durability. Further, photographic additives such as developing agents can be included. The undercoat layer is disclosed in JP-A-48-55.
03, Dosho 48-100203, Dosho 49-165
It may be as described in JP-A-07.

The silver halide emulsion layer is, for example, silver chloride,
It comprises silver bromide, silver chlorobromide, and those containing silver iodide. The silver halide crystal may contain a heavy metal salt such as a rhodium salt, an iridium salt, a palladium salt, a ruthenium salt, a nickel salt and a platinum salt, and the addition amount is 10 ^-8 to 10 ^-3 per mol of silver halide. It is a mole. The crystal form of silver halide is not particularly limited, and may be cubic or tetradecahedral grains, or core-shell type or tabular grains. The silver halide crystal may be a monodisperse or polydisperse crystal,
The average particle size is in the range of 0.2 to 0.8 μm. One preferable example is a monodisperse or polydisperse crystal containing rhodium salt or iridium salt and having a silver chloride content of 80 mol% or more.

The silver halide emulsion can be sensitized in various ways as it is manufactured or coated. It is preferable to chemically sensitize by methods well known in the art, for example, with sodium thiosulfate, alkyl thiourea, or with a gold compound such as gold rhodanide, gold chloride, or a combination of both. The silver halide emulsions can also be sensitized or desensitized positively or negatively with dyes such as cyanines, merocyanines. There is no particular limitation on the wavelength range that can be sensitized or desensitized. Therefore, ortho sensitization, panchromatic sensitization, helium-neon laser sensitization, argon laser sensitization, LED sensitization, semiconductor laser sensitization can be performed, and UV sensitization and visible light desensitization for bright rooms. I can feel it.

The surface layer present on top of the emulsion layer contains physical development nuclei. Physical development nuclei include fine particles of metal colloid such as silver, antimony, bismuth, cadmium, cobalt, lead, nickel, palladium, rhodium, gold and platinum, and sulfides, polysulfides, selenides of these metals, or those. It may be a mixture or a mixed crystal. The physical development core may or may not contain a hydrophilic binder, but gelatin, starch, dialdehyde starch, carboxymethyl cellulose, gum arabic, sodium alginate, hydroxyethyl cellulose, polystyrene sulfonic acid, vinyl imidazole and acrylamide A polymer, 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, the physical development nucleus layer may contain a developing agent such as hydroquinone, methylhydroquinone and catechol, and a known hardener such as formalin and dichloro-s-triazine.

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 anionic, cationic or neutral surfactants as coating aids. , Antifoggants, matting agents, thickeners, antistatic agents and the like.

The support for the lithographic printing plate of the present invention includes:
Paper or a synthetic or semi-synthetic polymer film, a metal plate such as aluminum or iron, and the like can be used as long as they 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 papers whose both surfaces or one surface is coated with a polyolefin polymer, polyester films, polyester films whose surfaces have been hydrophilized, and aluminum plates which have 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 developing solution used in the present invention contains an alkaline substance such as sodium hydroxide or potassium hydroxide,
Lithium hydroxide, sodium triphosphate, etc., sulfites as preservatives, silver halide solvents, such as thiosulfates,
Thiocyanates, cyclic imides, 2-mercaptobenzoic acid, amines, thickeners such as hydroxyethyl cellulose, carboxymethyl cellulose, antifoggants,
For example, potassium bromide, the compounds described in JP-A-47-26201, developers such as hydroquinones, catechol, 1-phenyl-3-pyrazolidone, development modifiers such as polyoxyalkylene compounds and onium compounds. Can be included. Further, compounds such as those described in U.S. Pat. No. 3,776,728, which improve ink transfer of the surface silver layer, can be used in the developing solution.

The surface silver layer after development of the lithographic printing plate of the present invention can be converted into ink receptivity or the receptivity can be enhanced by any known surface treatment agent. Examples of such a treatment liquid include Japanese Patent Publication No. 48-29723, US Pat.
721,559 and the like. The printing method, or the desensitizing liquid, the dampening liquid, or the like to be used may be a commonly known method.

[0029]

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

Example 1 A 135 g / m ² double-sided polyethylene-coated paper was provided on one side with a matting layer containing silica particles having an average particle size of 5 μ, and the opposite side was subjected to corona discharge machining, followed by carbon black and an average particle size. An undercoat layer (gelatin 3.5 g / m ² ) containing 7 μ of silica powder, and 1-phenyl-3
Ortho-sensitized high-sensitivity silver chloride emulsion containing pyrazolidone 0.1 g / m ² (including gelatin 0.8 g / m ² ) is simultaneously coated in two layers so as to have 1.0 g / m ² as silver nitrate. It was

As a hardening agent, 2,4-dichloro-6-
Hydroxy-s-triazine sodium in the undercoat layer 1
70 mg / m ² and 80 mg / m ² of N-methylol ethylene urea were contained in the emulsion layer. After drying, the core coating solution described in Example 2 of JP-A-58-21602 (containing a copolymer of acrylamide and imidazole of No. 3 as a polymer and 0.8 g of hydroquinone as a developing agent) was used.
/ M ² ) and then dried to obtain Comparative Example A of the present invention.
I made a planographic printing plate.

The lithographic printing plate as an example of the present invention was replaced with the hydrophilic polymer used in the lithographic printing plate (Comparative Example A), and was manufactured by Hayashibara Shoji Co., Ltd. Marster, Tetrap, Mabit, HS-. Twenty and one for Amamir
The planographic printing plates C, D, E, F, and G of the present invention were prepared by incorporating them so as to be 0 mg / m ² , respectively, and summarized in Table 1.

Further, as a lithographic printing plate of Comparative Example B, instead of the hydrophilic polymer used in Comparative Example A, pullulan 10 (PF-10 manufactured by Hayashibara Shoji Co., Ltd.) was added at 10 mg /
It was made to contain so that it might be m ² . Immediately after the production of these 7 types of lithographic printing plates and after storing them for 5 days under the conditions of 50 ° C. and 80% relative humidity, they were subjected to image exposure with a plate making camera having an image reversal mechanism, and the silver complex salt diffusion transfer development described below The solution was developed at 30 ° C. for 1 minute.

<Transfer developer> Water 700 ml Potassium hydroxide 20 g Anhydrous sodium sulfite 50 g 2-Mercaptobenzoic acid 1.5 g 2-Methylaminoethanol 15 g Water is added to make 1 liter. After the development treatment, 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. Dried in.

<Neutralization liquid> Water 600 ml Citric acid 10 g Sodium citrate 35 g Colloidal silica (20% liquid) 5 ml Ethylene glycol 5 ml Water is added to make 1 liter. The lithographic printing plate prepared by the above operation was mounted on an offset printing machine, and the following desensitizing liquid was applied all over the plate surface,
Printing was performed using the following dampening liquid.

<Desensitizing Solution> Water 600 ml Isopropyl alcohol 400 ml Ethylene glycol 50 g 3-Mercapto-4-acetamido-5-n-heptyl-1,2,4-triazole 1 g

<Moisturizing liquid> o-phosphoric acid 10 g nickel nitrate 5 g sodium nitrite 5 g ethylene glycol 100 g colloidal silica (20% liquid) 28 g Water is added to make 2 liters.

As the printing machine, Ryobi 3200CD (trademark of Ryobi KK offset printing machine) was used, and non-image area scumming and image skipping due to missing of the silver image area resulted in unusable printing. The number of printed sheets at that time was used for the judgment according to the following evaluation criteria. The ink is ABdick3-1012.
It was used. ○ 10,000 to 20,000 sheets △ 5,000 to 10,000 sheets × 2,000 to 5,000 sheets The printing results are shown in Table 2.

On the other hand, in order to see the water retention (background stain) of the non-image area, the ink is F Gloss Purple 68N made by Dainippon Ink.
Using the Eu-3,1% liquid (fountain water for PS plate / Etching liquid made by Fuji Film) as the dampening liquid, and using the Ryobi 3200CD as the printing machine The number of printed sheets at the time of rolling was judged according to the following evaluation criteria. ○ 1000 sheets or more △ 300 to 1000 sheets × 1 to 300 sheets The printing results are shown in Table 2.

[0040]

[Table 1]

In the above evaluation of the printing durability, an ink-carrying test was also conducted at the same time. In Table 2, the number of printed ink is evaluated.

[0042]

[Table 2]

From the above results, it was confirmed that the use of the monosaccharides and oligosaccharides of the present invention resulted in excellent printing characteristics, in particular, ink-carrying properties and water retention, and also excellent stability over time.

[0044]

According to the present invention, it is possible to improve ink retention and water retention of a lithographic printing plate to which the silver complex salt diffusion transfer method is applied, and to improve deterioration of the printing performance due to storage.

Claims (1)

[Claims] 1. A lithographic printing material to which a silver complex salt diffusion transfer method having at least a silver halide emulsion layer and a physical development nucleus layer on a support is applied, wherein the physical development nucleus layer and / or its adjacent layer is a single layer. A lithographic printing material comprising at least one sugar and an oligosaccharide.