JP3433876B2 - Lithographic printing plate - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lithographic printing material to which a silver complex salt diffusion transfer method is applied. 2. Description of the Related Art A lithographic printing plate is composed of an oleophilic image portion that receives oily ink and an oil-repellent non-image portion that does not receive ink. Generally, the non-image portion is formed of water. It is composed of a hydrophilic part that accepts. In normal lithographic printing, both water and ink are supplied to the plate surface, the image portion selectively receives color ink, and the non-image portion selectively receives water, and the ink on the image line is, for example, paper or the like. Printing is performed by transferring to a printing medium. [0003] Therefore, in order to obtain good printed matter, the difference between the lipophilicity and the hydrophilicity between the image area and the non-image area is sufficiently large, and when the water and the ink are supplied to the printing plate, the image area is not sufficient. It is necessary to accept the amount of ink and not to accept the ink at all 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 disclosed, for example, in US Pat.
No. 8,114, No. 4,134,769, No. 4-1
No. 60,670, No. 4,336,321, No. 4,
Nos. 501,811, 4,510,228, and 4,621,041, and the like. The exposed silver halide crystal undergoes chemical development by DTR development to produce a black color. It becomes silver and forms a hydrophilic non-image area.On the other hand, unexposed silver halide crystals are converted into a silver salt complex by a silver salt complexing agent in a developing solution and diffused to the physical development nucleus layer on the surface to form nuclei. Causes physical development to form an image portion mainly composed of physically developed silver having ink receptivity. [0005] As described above, the lithographic printing plate requires gelatin-
Since the silver image deposited on the physical development nucleus layer on the silver halide emulsion layer is used as an ink-accepting image area, the image area is higher than that of a general lithographic printing plate (for example, PS plate). The parts have insufficient resistance to mechanical abrasion, and have the drawback that the image area is missing or the ink receptivity of the image area is easily lost. In order to overcome this drawback, the hardness of gelatin is increased, a matting agent is contained in an undercoat layer or a silver halide emulsion layer to improve abrasion resistance, and the amount of physical development nuclei is increased. Then, soiling occurred. Further, there is a drawback in that when a lithographic printing plate is stored for a long period of time from production to plate making, scumming occurs and ink receptivity deteriorates. Further, various matting agents have been proposed in the past, but they are different in shape, size, composition, etc., and are mainly added to the undercoat layer to obtain effects (printing power, water retention, image quality, scratch resistance, etc.). )has seen. However, the water retention tended to decrease with the amount used. When these matting agents are used in the emulsion layer, the cause of further lowering of the water retention and further deterioration of the image (image skipping) occur, so that a good printed matter cannot be obtained. In order to improve water retention, Japanese Patent Application Laid-Open No.
No. 77747 proposes to include pullulan in the physical development nucleus layer and / or in a layer adjacent thereto, and in Japanese Patent Application Laid-Open Nos. 4-277748 and 5-88370, proposals have been made for hydrophilic polymers. The level of improvement was not enough. Also, the ink riding was not sufficiently good. In order to improve the printing durability, Japanese Patent Publication No. Sho 62-
296143, JP-B-63-226658, 63
No. 249852, Japanese Patent Publication No. 1-261643, JP-A-5-100430, JP-A-5-80518, and JP-A-5-80518.
Nos. 80519, 5-80520, 5-665
64, etc., various matting agent technologies and latex binders have been proposed, but printing durability, water retention, ink filling,
The print quality and scratch resistance are not sufficiently satisfactory, and there is a high demand for water retention and print quality. SUMMARY OF THE INVENTION An object of the present invention is to provide a silver complex salt diffusion material having excellent printing characteristics (printing durability, water retention, ink coverage, etc.), and particularly improved water retention and printing quality. An object of the present invention is to provide a lithographic printing plate using a transfer method. [0011] The above object of the present invention, in order to solve the problem] is the lithographic printing plate having at least a subbing layer and a silver halide emulsion layer and physical development nuclei layer on a support, halogen
This was achieved by including a primary particle silica matting agent having an average particle size of 0.1 to 1.0 μm in the silver halide emulsion layer . A lithographic printing plate targeted by the present invention has conventionally used a matting agent, and the matting agent has played an important role in the printing performance of the printing plate. Commonly known matting agents include silica (silicon dioxide), titanium oxide, magnesium oxide, barium sulfate, acrylic resins, polymers such as polystyrene, starch, etc.
Silica particles are preferably used. Conventionally, silica matting agents used in lithographic printing plates include, for example, thyricia manufactured by Fuji Silysia Ltd. and carplex manufactured by Shionogi & Co., Ltd.
μ silica particles. These silica particles are manufactured and supplied as secondary aggregates (particles aggregated). Generally, these secondary aggregated silica particles are mainly produced by a wet method, and the surface of the particles shows high hydrophilicity. However, when used for a lithographic printing plate, especially between aggregated particles enhances oil absorbency. However, it is difficult to obtain high hydrophilicity in the non-image area, and there has been a problem of stains due to ink adhesion in the non-image area. Further, these secondary aggregated silica particles are
When added to an undercoat layer or an emulsion layer, powdery silica particles are vigorously stirred and dispersed in a dispersion medium such as water, but the dispersion stability is poor, and a larger aggregate is formed during the production process. I was As a technique for stabilizing the dispersion of the secondary aggregated silica, there is a method of coexisting titanium oxide and a method of dispersing with ultrasonic waves in JP-A-5-80518. This is for preventing the particles from aggregating any more. The silica particles originally formed as secondary aggregate particles cannot be converted into primary particles by dispersion, pulverization (ball mill, sand mill) or the like. Conventionally, the size of silica particles produced and supplied as primary particles was up to 100 nm. For example, there is generally known colloidal silica, which is too small in particle size to function as a matting agent aimed at by the present invention at all, and in a gelatin solution, thickening and aggregation occur. There was a problem in the production process. The conventional secondary aggregated silica particles described above are:
It is a primary aggregate of 20 to 90 nm formed into a secondary aggregate of about 1 to 10 μm, and is a silica matting agent generally used in an undercoat layer of a lithographic printing plate. Until now, primary particles of silica particles having a particle size of 0.1 μm or more have not been supplied. However, the primary particles have been recently developed by Nissan Chemical Co., Ltd. Have been found to be useful and have led to the present invention. The primary particle silica (silicon dioxide) having a particle size of 0.1 μm or more can be obtained as a monodispersed silica sol from Nissan Chemical Co., Ltd. under the following trade names. MP-1040: Monodispersed silica sol with a mean particle size of 0.1 μm and a sharp particle size distribution MP-2040: Average particle size of 0.18 μm Same as above MP-3040: Average particle size of 0.34 μm Same as above ST-CZL: * average Monodisperse silica sol with a wide particle size distribution (particle size: 0.13 μm
The ET method and others are centrifugal sedimentation methods. This primary particle silica is prepared by a wet method, and is characterized by having a large number of hydroxyl groups and high hydrophilicity on the surface of the particle. Since the silica is supplied as a silica sol having high dispersion stability, it is dispersed in a gelatin liquid. Even in this case, it is considered that aggregation does not occur and primary particles exist in the constituent layers of the lithographic printing plate. Therefore, a highly hydrophilic printing plate having substantially no oil absorption can be obtained. In the preparation of the primary particle silica, the above-mentioned wet method is referred to as Egon Matijevie "Surface and Colloid Science", Volume 6, 3-10.
As described in detail in Section 0 (1973), it is mainly produced by neutralization with an acid using sodium silicate as a starting material, and is stabilized by an alkali such as NaOH or ammonia. Further, a sample containing alumina, sodium aluminate, or the like, which has been surface-treated with aluminum oxide, is also available. Further, the term "substantially no oil absorption" used herein means that the silica matting agent is a primary particle silica matting agent. It means that it does not absorb oil. In particular, conventionally, the smoothness of the printing plate surface has been increased in order to increase the water retention of the lithographic printing plate. For this reason, the thickness of the layer is relatively thin, and the silver halide emulsion layer arranged on the upper side hardly contains a matting agent. Is preferably used for the silver halide emulsion layer. The average particle size of the primary particle silica matting agent used in the present invention is 0.1 to 1.0 μm, more preferably 0.1 to 0.5 μm. The particle size of the silica matting agent (including primary particles and secondary aggregates) in the present invention is measured by a centrifugal sedimentation method. As described above, the primary particle silica matting agent used in the present invention is supplied as a silica sol having high dispersion stability.
Agglomeration does not occur, and the particles are arranged in the gelatin constituent layer of the lithographic printing plate in the form of primary particles. That is, they are arranged in the layer in a monodisperse state having a very narrow particle size distribution. Therefore, even if used in a large amount to some extent, the smoothness of the surface of the printing plate can be kept high, which contributes to improvement of water retention, printing durability and scratch resistance. The conventionally used secondary aggregated silica particles themselves have a wide particle size distribution and further aggregate in a dispersion medium and a gelatin solution, so that they can be arranged in the gelatin constituent layer in a monodispersed state. Did not. The silica matting agent of the primary particles of the present invention may be contained alone, or other matting agents (spherical, amorphous,
Flat matting agent, etc.). As the matting agent to be used in combination, a conventionally used secondary aggregate silica matting agent is preferable. By using them together, the characteristics of both can be utilized. That is, by containing a primary particle silica matting agent in the emulsion layer and a secondary aggregated silica matting agent of 1 μm or more in the undercoat layer, water retention, printing durability and scratch resistance can be further improved. The amount of the primary particle silica matting agent used in the present invention is affected by the amount of the matting agent used in combination and the amount of the binder, but is preferably 0.3 to 5.0 g / m ² , more preferably 0.1 g / m ^{2 for the} undercoat layer. 6 to 2.0 g / m ² , and 0.03 to
More preferably 3 g / m ² in the range of 0.05 ~1g / m ^2. The matting agent of the present invention has a high surface smoothness and is superior in print image quality and water retention even when used in a larger amount than other matting agents. Further, the use of a large amount improves the scratch resistance in the development processing. On the other hand, in Japanese Patent Application No. Hei 5-18964,
A combination use of a methylolated form of acrylamide and a water-soluble polysaccharide has also been proposed, but the effect of the polymer in these physical development nuclei layers is reduced to fine particles of the matting agent of the present invention, surface hydrophilicity, and substantially no oil absorption. Depending on the characteristics, the water retention can be further improved. When the primary particle silica matting agent of the present invention is used in the emulsion layer, as described above, by using a matting agent of 1.0 μm or more in the undercoat layer, the hydrophilicity of the surface can be maintained. High printing power and scratch resistance are ensured, and the most preferred lithographic printing plate is obtained. That is, by having a relatively large surface roughness in the undercoat layer and a small surface roughness in the emulsion layer, the lithographic printing plate surface has both high hydrophilicity and high abrasion resistance. The primary particle silica matting agent of the present invention is compatible with other matting agents having an average particle size of about 1.0 to 5.0 microns and has no significant thickening or coating failure. A preferable surface roughness as a plate is obtained. The center line average roughness Ra value of the lithographic printing plate is preferably 1.2 or less, and when the Ra value is 1.2 or more, the image quality gradually deteriorates. The center line average roughness of the lithographic printing plate is measured using a surface roughness profile measuring device, for example, Surfcom 500, Tokyo Seimitsu Co., Ltd.
It can be measured by using B. A portion of the measurement length 1 is extracted from the roughness curve in the direction of the center line, the center line of the extracted portion is defined as the X axis, the direction of the vertical magnification is defined as the Y axis,
When the roughness curve is represented by y = f (x), the center line average roughness Ra value is represented in units of micrometers, and can be calculated by the equation (1). ## EQU1 ## 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.
Gelatin hardeners include, for example, inorganic compounds such as chromium alum, aldehydes such as formalin, glyoxal, malealdehyde and glutaraldehyde, N-methylol compounds such as urea and ethylene urea, mucochloric acid, 2,3- Aldehydes such as dihydroxy-1,4-dioxane, 2,4-dichloro-6-hydroxy-S
Compounds having an active halogen, such as -triazine salts and 2,4-dihydroxy-6-chloro-triazine salts;
Divinyl sulfone, divinyl ketone, N, N, N-triacroylhexahydrotriazine, compounds having two or more active three-membered ethyleneimino groups or epoxy groups in the molecule, 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, in the case of two-layer simultaneous application, the diffusible hardener can be added to only one of the layers. The addition method can be added at the time of emulsion production or in-line at the time of coating. Part of the gelatin in the gelatin-containing layer of the present invention is water-soluble gelatin, starch, dextrin, albumin, sodium alginate, hydroxyethylcellulose, acacia, polyvinyl alcohol, polyvinylpyrrolidone, carboxymethylcellulose, polyacrylamide, styrene. It can 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 polymer binder in the undercoat layer is generally 0.5
More preferably to 10 g / m ² is 1 to 6 g / m ^2.
The undercoat layer may contain pigments such as carbon black, dyes and the like for the purpose of preventing halation. Further, a photographic additive such as a developing agent can be included. The undercoat layer is disclosed in JP-A-48-5503, JP-A-48-100203, and
It may be as described in JP-A-9-16507. The silver halide emulsion layer may be, for example, silver chloride,
It consists of 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, a platinum salt, and the like, in an amount of 10 ^-8 to 10 ^-3 per mol of silver halide. Is a mole. The crystal form of the silver halide is not particularly limited, and may be cubic to tetradecahedral grains, or core-shell or tabular grains. The silver halide crystal may be a monodisperse or polydisperse crystal,
Its average particle size is in the range of 0.2-0.8 μm. One preferred example is a monodispersed or polydispersed crystal containing 70% by mole or more of silver chloride containing a rhodium salt or an iridium salt. The silver halide emulsion can be sensitized in various ways as it is manufactured or coated. It is preferred to chemically sensitize by methods well known in the art such as, for example, with sodium thiosulfate, alkyl thioureas, or with gold compounds such as rhodium gold, gold chloride, or a combination of both. Silver halide emulsions can also be sensitized or desensitized positively or negatively by dyes such as cyanine, merocyanine and the like. There is no particular limitation on the wavelength range in which the sensitization or desensitization can be performed. Therefore, orthosensitization, panchromatic sensitization, helium-neon laser sensitization, argon laser sensitization, LED sensitization, and semiconductor laser sensitization can be performed, and UV sensitization and visible light reduction for a bright room can be performed. You can feel it. The surface layer present above the emulsion layer contains physical development nuclei. As physical development nuclei, silver, antimony, bismuth, cadmium, cobalt, lead, nickel, palladium, rhodium, gold, platinum and other metal colloid fine particles, and sulfides, polysulfides, selenides of these metals, or those It may be a mixture or a mixed crystal. The physical development nucleus may or may not contain a hydrophilic binder, but gelatin, starch, dialdehyde starch, carboxymethylcellulose, gum arabic, sodium alginate, hydroxyethylcellulose, polystyrene sulfonic acid, vinyl imidazole and acrylamide It may contain a polymer, a hydrophilic polymer such as polyvinyl alcohol or an oligomer thereof, and the content is preferably 0.5 g / m ² or less. Further, the physical development nucleus layer may contain a developing agent such as hydroquinone, methylhydroquinone, or catechol, or a known hardener such as formalin or dichloro-s-triazine. Each coating layer such as an undercoat layer, a silver halide emulsion layer and a physical development nucleus layer may contain some of anionic, cationic or neutral surfactants as coating aids. , An antifoggant, a matting agent, a thickener, an antistatic agent and the like. As the support of the lithographic printing plate of the present invention,
Paper, a 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. One or both surfaces of the support may be coated with one or more polymer films or metal thin films. The surface of these supports can be subjected to a surface treatment in order to improve the adhesion to the coating layer. Particularly preferably used supports are paper coated on both sides or one side with a polyolefin polymer, a polyester film, a polyester film having a hydrophilized surface, an aluminum plate having been subjected to a surface treatment, and the like.
These supports may contain pigments for preventing halation and solid fine particles for improving the surface properties. Further, the support may be light-transmissive so that backside exposure is possible. The developing solution used in the present invention includes an alkaline substance such as sodium hydroxide, potassium hydroxide,
Lithium hydroxide, tribasic sodium phosphate, etc., sulfites as preservatives, silver halide solvents such as thiosulfate,
Thiocyanates, cyclic imides, 2-mercaptobenzoic acid, amines and the like, thickeners such as hydroxyethylcellulose, carboxymethylcellulose and the like, antifoggants,
For example, potassium bromide, compounds described in JP-A-47-26201, etc., developers such as hydroquinones, catechol, 1-phenyl-3-pyrazolidone, etc., development modifiers such as polyoxyalkylene compounds, onium compounds, etc. Can be included. Further, as the developing solution, a compound or the like described in U.S. Pat. No. 3,776,728 which improves the ink running of the surface silver layer can be used. The surface silver layer after development of the lithographic printing plate of the present invention can be converted to ink receptivity or enhanced in receptivity with any known surface treating agent. Examples of such a processing solution include JP-B-48-29723 and U.S. Pat.
721, 559 and the like. The printing method, the desensitizing solution, the humidifying solution, and the like to be used can be a commonly known method. EXAMPLES The present invention will be described below with reference to examples, but of course, the present invention is not limited to these examples. Example 1 A matted layer containing silica particles having an average particle size of 4.0 microns (SY435 manufactured by Fuji Silysia Chemical Ltd.) was provided on one side (back coating) of a 175 micron subbed polyethylene terephthalate film, After the corona discharge machining on the opposite side, carbon black and an average particle size of 4.
0 micron silica powder (Fuji Silysia Chemical Ltd. SY435) 0.3g / m ² containing subbing layer (gelatin 3.5 g / m ² ) And an ortho-sensitized high-sensitivity silver chloride emulsion containing 0.1 g / m ² of 1-phenyl-3-pyrazolidone (containing 0.8 g / m ^{2 of} gelatin) as 1.0 g / m ^{2 of} silver nitrate. , Two layers were simultaneously coated. As hardening agents, 2,4-dichloro-6-
Sodium hydroxy-s-triazine was added to the undercoat
0 mg / m ² and containing, in the emulsion layer N- methylol urea was 80 mg / m ² containing. After drying,
The core coating solution described in Example 2 of Example No. 3-21602 (a polymer containing a copolymer of acrylamide of No. 3 and vinylimidazole, containing hydroquinone as a developing agent in an amount of 0.
8 g / m in a proportion of ²⁾ pullulan in JP 4-277747 a 2 mg / m ² was added to the coating to prepare a lithographic printing plate as a comparative example A without matting agent in the emulsion layer of the dried invention . In the lithographic printing plate described above, the conventional emulsion was added to the emulsion layer.
As a secondary aggregate silica matting agent, SY435 manufactured by Fuji Silysia Chemical Ltd. and FPS10 manufactured by Shionogi Pharmaceutical KK are used.
1. Lithographic printing plates containing acrylic resin (Eposter S) manufactured by Nippon Shokubai as a polymer matting agent and titanium oxide were prepared (Comparative Examples BE). In the emulsion layer, as the primary particle silica which is the matting agent of the present invention, Nissan Chemical Co., Ltd.
Lithographic printing plates F to K of the present invention were prepared with a configuration including P-1040, MP-2040, and MP-3040. Table 1 shows the specific composition of the matting agent. Immediately after the manufacture of these 11 types of lithographic printing plates and after storage for 5 days at 50 ° C. and a relative humidity of 80%, image exposure was carried out using a plate making camera having an image reversing mechanism. 1 at 30 ° C with diffusion transfer developer
For a 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 processing, the original plate was passed between two squeezing rollers to remove excess developer, and immediately processed with a neutralizing solution having the following composition at 25 ° C. for 20 seconds. And dried. <Neutralizing solution> Water 600 ml Citric acid 10 g Sodium citrate 35 g Colloidal silica (20% solution) 5 ml Ethylene glycol 5 ml Add water to make 1 liter. The lithographic printing plate created by the above operation is mounted on an offset printing machine, and the following desensitizing solution is applied to the plate surface,
Printing was performed using the following humidifying solution. <Desensitizing liquid> Water 600 ml Isopropyl alcohol 400 ml Ethylene glycol 50 g 3-mercapto-4-acetamido-5-n-heptyl-1,2,4-triazole 1 g <Humidifier> o-phosphorus Acid 10 g Nickel nitrate 5 g Sodium nitrite 5 g Ethylene glycol 100 g Colloidal silica (20% solution) 28 g Add water to make 2 liters. The printing machine used was Ryobi 3200CD (trademark of an offset printing machine manufactured by Ryobi KK), and image skipping occurred due to background stain on the non-image area and missing silver image area, making printing impossible. The number of printed sheets at the time was determined according to the following evaluation criteria. The ink was ABdick3-1012.
It was used. △ 10,000 to 20,000 sheets or more △ 5,000 to 10,000 sheets × 2,000 to 5,000 sheets On the other hand, in order to check the water retention (ground stain) of the non-image area, Dai Nippon Ink F Gloss Purple 68S
Using a 0.5% solution of Eu-3 (fountain solution for PS plate / etch solution manufactured by Fuji Film Co., Ltd.) as a humidifying solution, Ryobi 3200CD is used as a printing machine. The number of printed sheets at the time when the printing was stopped was judged according to the following evaluation criteria.以上 5000 sheets or more ○ 1000 to 5000 sheets ３００ 300 to 1000 sheets × 1 to 300 sheets
The image quality of the printed matter was evaluated simultaneously by the following evaluation method. The image quality was evaluated based on the following evaluation criteria to determine how a halftone dot of 100 lines made by a camera plate can be reproduced on a printed material. ◎ Reproduce halftone dots with clear contours. ○ The outline is slightly blurred. △ The outline is blurred. × Each halftone dot is irregular. Table 2 shows the printing results. [Table 1] [Table 2] From the above results, it was confirmed that the use of the matting agent of the present invention provided excellent printing characteristics, and particularly excellent water retention and printing image quality. According to the present invention, it is possible to provide a lithographic printing plate to which the silver complex salt diffusion transfer method is applied, which has excellent water retention and printing quality and printing durability.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G03F 7/07 G03C 8/06 501

Claims (1)

(57) At a [Claims 1, wherein at least the undercoat layer on the support, the planographic printing material by applying the silver complex diffusion transfer process having a silver halide emulsion layer and physical development nuclei layer, a halogen Silver halide emulsion layer
A lithographic printing material comprising a primary particle silica matting agent having an average particle size of 0.1 to 1.0 μm .