JP2014026215A - Method for making-up photopolymerizable lithographic printing plate and production device therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for making-up a photopolymerizable lithographic printing plate having excellent plate durability, and in which the problems of ink desorption properties and the collapse of dots in a shadow part are improved, and a production device used therefor.SOLUTION: The method for making up a photographic printing plate is characterized in that, in a method for making up a photopolymerizable lithographic printing plate having a hydrophilic layer on a base material and at least having a photosensitive layer on the hydrophilic layer, after the photopolymerizable lithographic printing plate is subjected to developing treatment, in a state where the face on the side having the hydrophilic layer of the lithographic printing plate comprises a moisture of 60 mass% or higher of the liquid absorption amount of the hydrophilic layer, post-exposure is performed.

Description

  The present invention relates to a plate making method and a plate making apparatus for a photopolymerizable lithographic printing plate having at least a hydrophilic layer on a support. More specifically, the present invention relates to a plate making method and a plate making apparatus for a photopolymerizable lithographic printing plate which is developed by chemicalless development containing substantially no alkali agent.

  In recent years, CTP (abbreviation of Computer To Plate) has been fully digitized due to the expansion of JDF (abbreviation of Job Definition Format), and work efficiency has been greatly improved. In the thermal type and photopoly type CTP printing plates which are currently mainstream, laser exposure is performed to output an image based on digital data.

  On the hardware side of output machines and printing plates, the creation of products that take into account human health and the environment as well as increased efficiency through the development of process-less and chemical-less systems has permeated. However, in the thermal type and photopoly type CTP printing plates which are currently mainstream, after exposure, the non-image area is eluted and removed using a developer containing a strong alkali agent, and then printed through a water washing and gumming process. Therefore, it was not sufficient as a chemical-less.

  There has been proposed a photopolymerizable lithographic printing plate that avoids the use of a strong alkaline agent-containing developer as described above and can be developed with water or the like. For example, Japanese Patent Application Laid-Open No. 2003-215801 (Patent Document 1) discloses a cationic water solution having a hydrophilic layer on a plastic film support and a phenyl group having a vinyl group substituted on the side chain on the hydrophilic layer. A photopolymerizable lithographic printing plate having a photosensitive polymer or a water-soluble polymer having a phenyl group substituted with a vinyl group in the side chain and a sulfonate group, and a photosensitive layer containing a photopolymerization initiator or an acid generator Has been. Since the image of such a photopolymerizable lithographic printing plate is an image obtained by polymerizing the above-mentioned water-soluble polymer, it tends to be difficult to obtain sufficient printing durability, and further by laser exposure. When an image is output, since exposure is performed in high illuminance and in a short time, photopolymerization does not proceed sufficiently, and improvement in printing durability is particularly important.

  As means for improving the printing durability problem, for example, in Japanese Patent Application Laid-Open No. 11-265069 (Patent Document 2) and Japanese Patent Application Laid-Open No. 2000-66416 (Patent Document 3), a plate developed after laser exposure is further applied to the entire surface. It describes that it is exposed (hereinafter referred to as post-exposure). Japanese Patent Laid-Open No. 2001-100434 (Patent Document 4) describes post-exposure with a light source having a specific light intensity, and Japanese Patent Laid-Open No. 2001-42546 (Patent Document 5) uses a mercury lamp. Post-exposure is described, and JP-A-2005-284041 (Patent Document 6) describes post-exposure with a light source including a wavelength of 600 to 900 nm.

  However, even if the printing durability is improved by post-exposure, depending on the printing conditions, there may be a problem with ink detachment, or there may be a problem such as tangling where the halftone dot of the shadow part is crushed. There has been a demand for a plate making method of a photopolymerizable lithographic printing plate which does not cause a problem.

  On the other hand, as processing apparatuses that perform post-exposure, for example, Japanese Patent Application Laid-Open No. 2008-203395 (Patent Document 7), Japanese Patent Application Laid-Open No. 2001-159811 (Patent Document 8), Japanese Patent Application Laid-Open No. 2008-15504 (Patent Document 9). JP, 2001-51426, A (patent documents 10) etc. are indicated. However, all of these post-exposure apparatuses are plate-making apparatuses that post-expose the dried plate after development. Depending on the printing conditions, there may be a problem with ink detachment, or halftones where the halftone dots of the shadow portion are crushed. There has been a need for a plate making apparatus capable of obtaining a lithographic printing plate that does not cause such a problem.

JP 2003-215801 A Japanese Patent Laid-Open No. 11-265069 JP 2000-66416 A JP 2001-1000043 A JP 2001-42546 A Japanese Patent Laying-Open No. 2005-284041 JP 2008-203395 A Japanese Patent Laid-Open No. 2001-159811 JP 2008-15504 A JP 2001-51426 A

  An object of the present invention is to provide a plate making method of a photopolymerizable lithographic printing plate which is excellent in printing durability and has improved problems such as ink detachability and network entanglement. It is another object of the present invention to provide a plate making apparatus capable of obtaining a lithographic printing plate which is excellent in printing durability and has improved problems such as ink detachability and screen entanglement.

The present invention has been achieved by the following invention.
1) A plate making method of a photopolymerizable lithographic printing plate having a hydrophilic layer on a substrate and having at least a photosensitive layer on the hydrophilic layer, and after developing the photopolymerizable lithographic printing plate, A photopolymerizable lithographic printing plate characterized in that the surface on the side having a hydrophilic layer of the lithographic printing plate is post-exposed in a state containing moisture of 60% by mass or more of the liquid absorption amount of the hydrophilic layer. Plate making method.
2) A plate making apparatus for post-exposure after developing the photopolymerizable lithographic printing plate after exposure, followed by a liquid squeezing portion for removing water adhering to the lithographic printing plate after development, and a light source for post-exposure A plate making apparatus comprising: a first drying processing unit having:

  ADVANTAGE OF THE INVENTION According to this invention, the plate-making method of the photopolymerizable lithographic printing plate which was excellent in printing durability and improved the problems, such as ink detachment | desorption property and a net tangling, can be provided. In addition, it is possible to provide a plate making apparatus capable of obtaining a lithographic printing plate having excellent printing durability and improved problems such as ink detachability and screen entanglement.

The schematic diagram which shows an example of the plate-making apparatus of this invention. The schematic diagram which shows the drying in this invention, a post-exposure process part, and a peripheral part. The schematic diagram which shows an example of the conventional plate making apparatus. The schematic diagram which shows the drying in the conventional plate-making apparatus, a post-exposure process part, and a peripheral part.

  Hereinafter, the present invention will be described in detail. The photopolymerizable lithographic printing plate used in the plate making method of the present invention has a hydrophilic layer on a substrate and at least a photosensitive layer on the hydrophilic layer.

<Base material>
Examples of the substrate of the photopolymerizable lithographic printing plate of the present invention include an aluminum plate, various plastic films, and paper laminated with various plastics. Among them, various plastic films that are flexible and are less deformed by tension are preferably used. Preferred examples of the plastic film substrate include polyethylene terephthalate, polyethylene naphthalate, polyethylene, polypropylene, polystyrene, polyvinyl acetal, polycarbonate, cellulose diacetate, cellulose triacetate, cellulose propionate, cellulose butyrate, and cellulose nitrate. In particular, polyethylene terephthalate and polyethylene naphthalate are preferably used.

  The surface of these base materials may be surface-treated in order to improve adhesion with a hydrophilic layer or a backing layer provided as necessary. Examples of such surface treatment include corona discharge treatment, flame treatment, plasma treatment, and ultraviolet irradiation treatment. As a further surface treatment, an undercoat layer may be provided on the base material in order to enhance the adhesiveness with the hydrophilic layer provided on the base material.

<Hydrophilic layer>
As the hydrophilic layer of the photopolymerizable lithographic printing plate of the present invention, a hydrophilic layer containing a hydrophilic binder and an inorganic filler is preferably used.

<Inorganic filler>
Examples of the inorganic filler used in the hydrophilic layer of the photopolymerizable lithographic printing plate of the present invention include calcium carbonate, magnesium carbonate, zinc oxide, titanium dioxide, barium sulfate, aluminum hydroxide, zinc hydroxide, colloidal silica, and pore silica. , Kaolin and the like. Of these, titanium dioxide, barium sulfate, aluminum hydroxide, and colloidal silica are preferable.

  Titanium dioxide may be either a rutile type or an anatase type, and the production method is not limited to either the sulfuric acid method or the chlorine method. You may use them individually or in mixture. Furthermore, from the viewpoint of dispersion stability and other functionality, it is possible to selectively use those subjected to various surface treatments. Examples of commercially available titanium dioxide include SR-1, R-650, R-5N, R-7E, R-3L, A-110, and A-190 from Sakai Chemical Industry Co., Ltd. ), Typek R-580, R-930, A-100, A-220, CR-58, Titanium Industry Co., Ltd., Kronos KR-310, KR-380, KA-10, KA-20, etc., from Teika Co., Ltd., Titanics JR-301, JR-600A, JR-800, JR-701, etc., from DuPont, Thailand Pure R-900, R-931 Is mentioned.

  As barium sulfate, it is preferable to use precipitated barium sulfate produced by adding a sulfate aqueous solution to a barium chlorine solution and chemically precipitating. Precipitated barium sulfate is commercially available, for example, as “Variace” from Sakai Chemical Industry Co., Ltd., having various particle diameters or surface-treated ones, but any of them can be used in the present invention.

  Aluminum hydroxide mixes bauxite, which is an ore containing alumina, with caustic soda or sodium aluminate solution, extracts the alumina component under high temperature and high pressure conditions, separates and removes red mud as a dissolution residue from the extract, A clarified sodium aluminate solution is obtained. Thereafter, seeds can be added to the solution to crystallize aluminum hydroxide, and the obtained aluminum hydroxide can be pulverized. Various grades of aluminum hydroxide are commercially available from Showa Denko Co., Ltd. as “Hijilite”, and any grade can be used in the present invention.

  The colloidal silica used in the present invention may have a spherical shape, and a chain or pearl necklace colloidal silica is also preferably used.

The colloidal silica may be composed of a simple substance of SiO ₂ , but it is also possible to use a silica whose surface is slightly modified with Al ₂ O ₃ or the like in order to change the pH dependence of the dispersibility of silica. Further, an alkali dispersion or an acidic dispersion of colloidal silica can be selected and used depending on the pH of the coating liquid for the hydrophilic layer.

  Examples of the spherical silica include “Snowtex XS”, “Snowtex S”, “Snowtex 20”, “MP-2040”, “MP-1040”, and “Snowtex ZL” manufactured by Nissan Chemical Industries, Ltd. Etc. These colloidal silicas have a pH of 9 or more, but when preparing an acidic coating solution, it is possible to use “Snowtex O”, “Snowtex OL”, etc., which are made by demineralizing Na ions to make them acidic. it can. Examples of the chain silica include “Snowtex UP” manufactured by Nissan Chemical Industries, Ltd., and examples of the necklace-like silica include “Snowtex PS-S” and “Snowtex PS-M”.

  Further, the inorganic filler contained in the hydrophilic layer is present in the range of the particle size distribution of the inorganic filler in the range of 0.2 μm or more and less than 0.6 μm and the range of 0.6 μm or more and less than 1.5 μm. When the distribution frequency of the inorganic filler existing in the range of less than 6 μm is fx and the distribution frequency of the inorganic filler existing in the range of 0.6 μm or more and less than 1.5 μm is fy, the fx / fy ratio is 1.5 or more. More preferably, the distribution frequency fy is 25% or more. The fx / fy ratio is preferably 2.0 or more, and the upper limit of the fx / fy ratio is preferably less than 3.5. In the above-mentioned range, for example, when a plurality of peaks are present in the range of 0.2 μm or more and less than 0.6 μm, the distribution frequency fx may be obtained with the higher peak. In the case where the height of the recess between two peaks is 60% or more of the higher peak, it is regarded as one peak in the present invention. As a result, a photopolymerizable lithographic printing plate that is particularly excellent in ink detachment property and reticulation resistance can be obtained.

  The particle size distribution in the present invention is a volume-based particle size distribution, which is an index indicating what kind of particle size the sample particle group to be measured is and what ratio is configured, and is generally known It can be measured by the method. For example, a sieving method, a Coulter method (Coulter principle), a dynamic light scattering method, an image analysis method, a laser diffraction scattering method, etc. are known as the measuring method. In the present invention, the particle size to be measured and reproducibility are known. From the viewpoint of operability and the like, a laser diffraction / scattering method is preferably used. For example, it can be measured by LA-920 (laser diffraction / scattering type particle size distribution measuring apparatus) manufactured by Horiba, Ltd. The distribution frequency can be obtained as a distribution of the existence ratio for each size (particle diameter) based on the measurement result.

  The particle size distribution and distribution frequency in the present invention are measured by measuring the inorganic filler dispersed in the coating solution, or by measuring the inorganic filler in a solution obtained by re-dissolving the dried coating film of the applied hydrophilic layer with an alkali. You can ask for it. As will be described later, in the present invention, two or more kinds of inorganic fillers can be used together. However, in the laser diffraction scattering method preferably used in the present invention, the light intensity distribution pattern is obtained from the Fraunhofer diffraction theory and the Mie scattering theory. Therefore, a refractive index specific to the object is required, and it is difficult to accurately measure the particle size distribution and distribution frequency of a coating liquid containing two or more inorganic fillers having different refractive indexes. However, in such a case, the particle size distribution and distribution frequency of each inorganic filler alone are measured in advance, and two or more kinds of inorganic fillers are added by multiplying the obtained measurement result by the addition ratio in the coating liquid as a coefficient. The particle size distribution and distribution frequency of the coating liquid used in combination can be determined.

  In order to obtain the particle size distribution of the inorganic filler described above, an inorganic filler having an average primary particle size of 0.1 μm or more and less than 0.6 μm and an inorganic filler having an average primary particle size of 0.6 μm or more and less than 2.0 μm are combined. It is preferable to use it, and if it is such a combination, the inorganic filler may be further used in combination with three or four kinds. The addition amount of the inorganic filler is preferably 60% by mass or more, more preferably 70% by mass or more, based on the total solid content of the hydrophilic layer.

  Further, in the hydrophilic layer having the above particle size distribution, it is preferable not to use silicon-containing compounds such as colloidal silica, pore silica, and kaolin, and the content of these silicon-containing compounds is reduced to the total inorganic filler in the hydrophilic layer. Is preferably 5% by mass or less, more preferably 3% by mass or less, particularly preferably 1% by mass or less, and particularly preferably 0.5% by mass or less.

<Hydrophilic binder>
As the hydrophilic binder used in the hydrophilic layer of the photopolymerizable lithographic printing plate of the present invention, natural products obtained from algae such as starch, seaweed mannan, agar and sodium alginate, mannan, pectin, tragacanth gum, Plant gums such as karaya gum, xanthine gum, guar bin gum, locust bing gum, gum arabic, homopolysaccharides such as dextran, glucan, xanthan gum, and levan, heteropolysaccharides such as succinoglucan, pullulan, curdlan, and xanthan gum Examples include microbial mucilage, glue, gelatin, protein such as casein and collagen, chitin and derivatives thereof. Semi-natural products (semi-synthetic products) include cellulose derivatives, modified gums such as carboxymethyl guar gum, cultured starches such as dextrin, processed starches such as oxidized starches and esterified starches. . On the other hand, synthetic products include polyvinyl alcohol, partially acetalized polyvinyl alcohol, allyl-modified polyvinyl alcohol, modified polyvinyl alcohol such as polyvinyl methyl ether, polyvinyl ethyl ether, and polyvinyl isobutyl ether, polyacrylate, and polyacrylate ester partial saponified product. Polyacrylic acid derivatives and polymethacrylic acid derivatives such as polymethacrylic acid salts and polyacrylamides, polyethylene glycol, polyethylene oxide, polyvinylpyrrolidone, vinylpyrrolidone / vinyl acetate copolymer, carboxyvinyl polymer, styrene / maleic acid copolymer Examples thereof include a polymer, a styrene / crotonic acid copolymer, and a water-soluble polymer described in JP-A-2008-265297. Among these, gelatin is preferably used.

  Moreover, content of the hydrophilic binder in a hydrophilic layer has a preferable content ratio between the said inorganic fillers, and it is preferable that it is 5-30 mass% with respect to 100 mass parts of all inorganic fillers, and 10-25 masses. % Is more preferable. When it exceeds 30% by mass, the filler filling density is lowered and sufficient hydrophilicity cannot be imparted, and the soil resistance and the entanglement resistance may be lowered. On the other hand, if it is less than 5% by mass, the handling property of the coating liquid may be lowered, or cracks may occur after forming the hydrophilic layer.

<Crosslinking agent>
The hydrophilic layer of the photopolymerizable lithographic printing plate of the present invention preferably contains a crosslinking agent. As the crosslinking agent to be used, for example, melamine resin, polyisocyanate compound, aldehyde compound, silane compound, chromium alum, divinyl sulfone and the like can be suitably used, but particularly preferred crosslinking agent is divinyl when the hydrophilic binder is gelatin. Sulfone. The blending amount of the crosslinking agent is preferably 5 to 35% by mass, more preferably 10 to 25% by mass, based on the solid content of the hydrophilic binder. As for the method of adding the crosslinking agent, there are a method of adding the hydrophilic layer coating liquid when it is manufactured, a method of adding it in-line immediately before coating, and any method may be used.

  In order to sufficiently crosslink the hydrophilic layer, for example, 0.5 to 0.5 at a temperature of 30 to 60 ° C., preferably 40 to 50 ° C., between the formation of the hydrophilic layer and the application of the photopolymerizable photosensitive layer. It is preferable to perform a heating treatment for 10 days, preferably 1 to 7 days. Even if the hydrophilic layer is exposed by the development process after the exposure by such a heating process and is subjected to printing as a non-image part at the time of printing, it is natural as printability, but it is sufficient in terms of scratch resistance. Performance can be expressed.

<Photosensitive layer>
The photopolymerizable lithographic printing plate of the present invention has at least a photosensitive layer on the hydrophilic layer. Such a photosensitive layer preferably contains a photopolymerization initiator and a compound having a polymerizable double bond group.

<Photopolymerization initiator>
Conventionally known compounds can be used as the photopolymerization initiator. For example, trihaloalkyl-substituted compounds (for example, s-triazine compounds and oxadiazole derivatives as trihaloalkyl-substituted nitrogen-containing heterocyclic compounds, trihaloalkylsulfonyl compounds), organic boron salts, hexaarylimidazoles, titanocene compounds, thio compounds And organic peroxides. Among these photopolymerization initiators, trihaloalkyl-substituted compounds and organic boron salts are particularly preferably used. More preferably, a combination of a trihaloalkyl-substituted compound and an organic boron salt is used. High sensitivity can be achieved by combining trihaloalkyl-substituted compounds and organic boron salts, and since the radical species generated by using these in combination can be stabilized, sensitivity can be further improved. Is preferable.

  The trihaloalkyl-substituted compound that is a photopolymerization initiator is specifically a compound having at least one trihaloalkyl group such as a trichloromethyl group or a tribromomethyl group in the molecule. Preferred examples include the trihaloalkyl group. S-triazine derivatives and oxadiazole derivatives are exemplified as compounds in which is bonded to a nitrogen-containing heterocyclic group, or a trihaloalkylsulfonyl in which the trihaloalkyl group is bonded to an aromatic ring or a nitrogen-containing heterocyclic ring via a sulfonyl group Compounds.

  Particularly preferred examples of compounds in which a trihaloalkyl group is bonded to a nitrogen-containing heterocyclic group and trihaloalkylsulfonyl compounds are shown below.

  The organoboron anion constituting the organoboron salt is represented by the following general formula 1.

In the formula, each of R ₁ , R ₂ , R ₃ and R ₄ may be the same or different, and represents an alkyl group, aryl group, aralkyl group, alkenyl group, alkynyl group, cycloalkyl group or heterocyclic group. Represent. Of these, it is particularly preferred that one of R ₁ , R ₂ , R ₃ and R ₄ is an alkyl group and the other substituent is an aryl group.

  Examples of the cation constituting the organic boron salt include alkali metal ions and onium compounds, but onium salts are preferred, for example, ammonium salts such as tetraalkylammonium salts, sulfonium salts such as triarylsulfonium salts, and triarylalkyls. Examples thereof include phosphonium salts such as phosphonium salts. Examples of particularly preferred organic boron salts are shown below.

  The content of the photopolymerization initiator as described above is preferably in the range of 1 to 50% by mass and more preferably in the range of 5 to 30% by mass with respect to the compound having a polymerizable double bond group described later. It is preferable.

<Compound having a polymerizable double bond group>
The compound having a polymerizable double bond group is a polymer compound having a polymerizable double bond group or a low molecular compound having a polymerizable double bond group. From the viewpoint of photopolymerization efficiency, it is preferable to use a low molecular weight compound having a polymerizable double bond group in combination.

  The polymer compound having a polymerizable double bond group will be described. The polymer compound having a polymerizable double bond group is a polymer compound formed by an arbitrary repeating unit, and a polymer compound in which a polymerizable double bond group is bonded to a side chain through an arbitrary linking group. It is. Among them, a polymer compound having a vinyl group as a reactive double bond group is preferably used, and a polymer compound in which a phenyl group substituted with a vinyl group is bonded to the main chain directly or via an arbitrary linking group is particularly preferably used. It is done. In addition, in order to enable development with an alkaline developer or a neutral developer (chemicalless developer), a carboxyl group, a sulfonic acid group, a quaternary ammonium group, etc., which are connected to the main chain via an arbitrary connecting group However, among them, a polymer compound having a sulfonic acid group can be preferably used because of its high developability. The sulfonic acid group may form a salt (for example, sodium salt, potassium salt, lithium salt, amine salt, etc.). These linking groups are not particularly limited, and include any group, atom, or a combination thereof. The phenyl group and sulfonic acid group substituted with a vinyl group may be independently bonded to the main chain, or the phenyl group and sulfonic acid group substituted with a vinyl group share part or all of the linking group. You may combine in the form to do.

  In the phenyl group substituted by the vinyl group, the phenyl group may be substituted, and the vinyl group is a halogen atom, carboxyl group, sulfo group, nitro group, cyano group, amide group, amino group, alkyl group. , An aryl group, an alkoxy group, an aryloxy group and the like may be substituted.

  The polymer compound in which the phenyl group substituted with the vinyl group of the present invention is bonded to the main chain directly or through an arbitrary linking group has, in detail, one having a group represented by the following general formula 2 in the side chain. preferable.

In the formula, R ₅ , R ₆ and R ₇ may be the same or different and are each a hydrogen atom, halogen atom, carboxyl group, sulfo group, nitro group, cyano group, amide group, amino group, alkyl group. Group, aryl group, alkoxy group, aryloxy group, alkylsulfanyl group, arylsulfanyl group, alkylamino group, arylamino group, acyl group, alkoxycarbonyl group, aryloxycarbonyl group, alkylsulfonyl group, arylsulfonyl group An alkyl group and an aryl group constituting these groups are a halogen atom, a carboxyl group, a sulfo group, a nitro group, a cyano group, an amide group, an amino group, an alkyl group, an aryl group, an alkenyl group, a hydroxy group, Alkoxy group, aryloxy group, alkylsulfanyl group, It may be substituted with a reelsulfanyl group, an alkylamino group, an arylamino group, an acyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, an alkylsulfonyl group, an arylsulfonyl group, or the like. Among these groups, those in which R ₅ and R ₆ are hydrogen atoms and R ₇ is a hydrogen atom or a lower alkyl group having 4 or less carbon atoms (for example, a methyl group, an ethyl group, etc.) are particularly preferable.

In the formula, R ₈ is hydrogen atom, halogen atom, carboxyl group, nitro group, cyano group, amide group, amino group, alkyl group, aryl group, alkoxy group, aryloxy group, alkylsulfanyl group, arylsulfanyl group, alkylamino. And a group selected from a group, an arylamino group, an acyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, an alkylsulfonyl group, and an arylsulfonyl group. The alkyl group and aryl group constituting these groups are halogen atom, carboxyl group, sulfo group, nitro group, cyano group, amide group, amino group, alkyl group, aryl group, alkenyl group, alkynyl group, hydroxy group. , Alkoxy groups, aryloxy groups, alkylsulfanyl groups, arylsulfanyl groups, alkylamino groups, arylamino groups, acyl groups, alkoxycarbonyl groups, aryloxycarbonyl groups, alkylsulfonyl groups, arylsulfonyl groups, etc. good.

In the formula, L ₁ represents an atom selected from a carbon atom, a nitrogen atom, an oxygen atom and a sulfur atom, or a polyvalent linking group consisting of an atom group selected from a hydrogen atom, a carbon atom, a nitrogen atom, an oxygen atom and a sulfur atom. Represent. Specific examples include groups composed of the structural units exemplified below and the heterocyclic groups shown below. These groups may be used alone or in any combination of two or more.

The linking group L ₁ preferably includes a heterocyclic ring. Examples of the heterocyclic ring constituting L ₁ include pyrrole ring, pyrazole ring, imidazole ring, triazole ring, tetrazole ring, isoxazole ring, oxazole ring, oxadiazole ring, isothiazole ring, thiazole ring, thiadiazole ring, thia Triazole ring, indole ring, indazole ring, benzimidazole ring, benzotriazole ring, benzoxazole ring, benzthiazole ring, benzselenazole ring, benzothiadiazole ring, pyridine ring, pyridazine ring, pyrimidine ring, pyrazine ring, triazine ring, quinoline And a nitrogen-containing heterocycle such as a ring and a quinoxaline ring, a furan ring, a thiophene ring, and the like. These heterocycles may have a substituent.

  When the polyvalent linking group described above has a substituent, examples of the substituent include a halogen atom, a carboxyl group, a sulfo group, a nitro group, a cyano group, an amide group, an amino group, an alkyl group, an aryl group, an alkenyl group, and an alkynyl group. Group, hydroxy group, alkoxy group, aryloxy group, alkylsulfanyl group, arylsulfanyl group, alkylamino group, arylamino group, acyl group, alkoxycarbonyl group, aryloxycarbonyl group, alkylsulfonyl group, arylsulfonyl group, etc. It is done.

In the formula, m ₁ represents an integer of 0 to 4, p ₁ represents an integer of 0 or 1, and q ₁ represents an integer of ₁ to 4.

  The polymer compound having a polymerizable double bond group of the present invention may be a polymer comprising only a repeating unit having a phenyl group in which a vinyl group is substituted on the side chain and a repeating unit having a sulfonic acid group. As long as it does not interfere with the effects of the present invention, it may be a polymer into which another repeating unit is further introduced. Further, it may be a copolymer with another monomer, and such a monomer may be used alone or two or more of them may be used.

  Moreover, the high molecular compound which has a polymerizable double bond group of this invention can introduce | transduce arbitrary substituents into the terminal of a polymer principal chain by using a chain transfer agent. Specifically, linear alkane thiols, particularly linear alkane thiols substituted with silicon atoms bonded to alkoxy groups or halogen atoms, are preferably used because they can be used at the time of polymerization as a chain transfer agent. Can do. Examples of such chain transfer agents include 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyldimethoxymethylsilane, 3-mercaptopropyltriethoxysilane, 3-mercaptopropyltrichlorosilane, 3-mercaptopropyldichloromethylsilane, 4 -Mercaptobutyltrimethoxysilane, 4-mercaptobutyldimethoxymethylsilane, 4-mercaptobutyltriethoxysilane, 4-mercaptobutyltrichlorosilane, 4-mercaptobutyldichloromethylsilane, and the like. May be bonded via an oxygen atom by hydrolytic condensation to form a siloxane bond.

  Preferred examples of the polymer compound having a polymerizable double bond group of the present invention are shown below, but the present invention is not limited to these examples. The numbers in the exemplified structural formulas represent the mass% of each repeating unit in the copolymer total composition of 100 mass%.

  The weight average molecular weight of the polymer compound having a polymerizable double bond group of the present invention is preferably in the range of 1,000 to 1,000,000, and more preferably in the range of 50,000 to 600,000. In the present invention, the polymer compound having a polymerizable double bond group may be used alone or in combination of two or more.

  Next, the low molecular weight compound having a polymerizable double bond group used in the present invention will be described. The low molecular compound having a polymerizable double bond group in this case can be preferably used as long as it is a compound that undergoes polymerization by radicals generated by the photodecomposition of the photopolymerizable initiator. Furthermore, when a compound having two or more polymerizable double bond groups in the molecule is used, a cross-linked product is formed as a result of polymerization by radicals, so that a photopolymerizable lithographic printing plate was constructed. In some cases, since a crosslinked hard image part film is formed, a printing plate having excellent printing durability and ink transferability can be obtained, which can be used very preferably. Examples of compounds having a polymerizable double bond group that can be used for such purposes include 1,4-butanediol diacrylate, 1,6-hexanediol diacrylate, neopentyl glycol diacrylate, and tetraethylene glycol diacrylate. Polyfunctional acrylic monomers such as trisacryloyloxyethyl isocyanurate, tripropylene glycol diacrylate, trimethylolpropane triacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, etc., or acryloyl group, methacryloyl group Polyester (meth) acrylate, urethane (meth) acrylate, epoxy (meth) acrylate, etc. are also used in the same way as various oligomers introduced with That.

  The photosensitive layer of the photopolymerizable lithographic printing plate of the present invention preferably contains a compound for sensitizing the above-mentioned photopolymerization initiator. As compounds that increase the sensitivity in the wavelength region of 400 to 430 nm, cyanine dyes, coumarin compounds described in JP-A-7-271284, JP-A-8-29973, etc., JP-A-9-230913, Carbazole compounds described in JP-A No. 2001-42524 and the like, carbomerocyanine dyes described in JP-A-8-262715, JP-A-8-272096, JP-A-9-328505, and the like, JP-A-4-194857, JP-A-6-295061, JP-A-7-84863, JP-A-8-220755, JP-A-9-80750, JP-A-9-236913, etc. Aminobenzylidene ketone dyes, JP-A-4-184344, JP-A-6-301208, The pyromethine dyes described in Kaihei 7-225474, JP-A-7-5585, JP-A-7-281434, JP-A-8-6245, etc., and JP-A-9-80751 Styryl dyes or (thio) pyrylium compounds. Of these, cyanine dyes, coumarin compounds or (thio) pyrylium compounds are preferred.

  As other elements constituting the photosensitive layer of the photopolymerizable lithographic printing plate of the present invention, various colorants are preferably added for the purpose of improving visibility. As a colorant added for such purposes, an aqueous dispersion of a color pigment can be most preferably used. As an example of an aqueous dispersion of such a pigment, any material in which various colored pigments such as black, blue, red, green and yellow are dispersed in water in the presence of various water-soluble dispersants can be used. . In particular, carbon black, phthalocyanine blue, phthalocyanine green, and the like as pigments are particularly preferred because they are readily available and relatively easy to disperse in water. Examples of dispersants that can be used to disperse these pigments in water include water-soluble nonionic surfactants having an oxyethylene group such as polyethylene glycol and polypropylene glycol, polyacrylic acid, and polyvinylpyrrolidone. , Polystyrene-maleic acid half ester copolymer, polystyrene-maleic acid copolymer, and other various water-soluble polymers. Such a dispersant is preferably contained in a range of 5 to 50 parts by mass with respect to 100 parts by mass of the color pigment. Furthermore, when using a color pigment, it is preferable that it is contained in 1-30 mass parts with respect to 100 mass parts of compounds which have a polymerizable double bond.

  The photosensitive layer of the photopolymerizable lithographic printing plate of the present invention preferably contains a silane coupling agent. An excellent printing durability can be obtained when the photosensitive layer contains a silane coupling agent, but in the negative photosensitive lithographic printing plate having the hydrophilic layer of the present invention, stain resistance, anti-glare property, In addition, the printing durability is improved without deteriorating the ink detachability and the like, and therefore, it is particularly preferable.

  The silane coupling agent is not particularly limited as long as the purpose is achieved, and any silane coupling agent can be used. For example, epoxycyclohexylethyltrimethoxysilane, glycidoxypropyltrimethoxysilane, acryloxypropyltrimethoxysilane, methacryloxypropyltrimethoxysilane, mercaptopropyltrimethoxysilane, mercaptopropyltriethoxysilane, methyltrimethoxysilane, dimethyldimethoxy Silane, phenyltrimethoxysilane, diphenyldimethoxysilane, methyltriethoxysilane, dimethyldiethoxysilane, phenyltriethoxysilane, diphenyldiethoxysilane, styryltrimethoxysilane, styryltriethoxysilane, hexyltrimethoxysilane, decyltrimethoxysilane , Vinyltris (3-methoxyethoxy) silane, vinyltriethoxysilane, vinyltrimeth Sisilane, 3-methacryloyloxypropyltrimethoxysilane, 3-acryloyloxypropyltrimethoxysilane, 3-methacryloyloxypropyltriethoxysilane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 3-glycidoxypropyl Trimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-methacryloyloxypropylmethyldiethoxysilane, N-β (aminoethyl) -γ-aminopropyltrimethoxysilane, N-β (aminoethyl) -amino Propylmethyldimethoxysilane, 3-aminopropyltriethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-chloropropyltrimethoxysilane 3-isocyanatopropyltriethoxysilane and the like. Among them, epoxycyclohexylethyltrimethoxysilane, glycidoxypropyltrimethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, acryloxypropyltrimethoxysilane, methacryloxypropyltrimethoxysilane, mercaptopropyltrimethoxysilane, mercaptopropyltri Particularly preferred are trialkoxysilanes such as ethoxysilane. In addition, a silane coupling agent may be used individually by 1 type, and may use 2 or more types together by arbitrary combinations and a ratio.

  The amount of the silane coupling agent contained in the photosensitive layer is preferably in the range of 0.2 to 20% by mass, more preferably 0.5%, based on the compound having a polymerizable double bond group contained in the photosensitive layer. It is the range of -10 mass%.

  As another element constituting the photosensitive layer, a polymerization inhibitor is preferably added in order to prevent a curing reaction in a dark place due to thermal polymerization, for long-term storage. Polymerization inhibitors preferably used for such purposes include hydroquinones, catechols, naphthols, cresols and other compounds having various phenolic hydroxyl groups, quinone compounds, 2,2,6,6-tetramethylpiperidine- N-oxyls, N-nitrosophenylhydroxylamine salts and the like are preferably used. In this case, the polymerization inhibitor is preferably added in an amount of 0.01 to 10 parts by mass with respect to 100 parts by mass of the total solid content of the photosensitive composition of the present invention.

  Regarding the dry solid content coating amount of the photosensitive layer itself, it is preferably formed with a dry solid content coating amount in the range of 0.3 to 10 g per square meter in dry mass, and more preferably in the range of 0.5 to 3 g. It is extremely preferable for exhibiting good resolution and ensuring printing durability of fine line images and fine dot images, and at the same time, greatly improving ink transportability.

<Protective layer>
In the photopolymerizable lithographic printing plate of the present invention, it is also preferable to further provide a protective layer on the photosensitive layer. The protective layer prevents exposure of low molecular weight compounds such as oxygen and basic substances present in the atmosphere that hinder the image formation reaction caused by exposure in the photosensitive layer to further improve exposure sensitivity in the atmosphere. It has a favorable effect of improving. Furthermore, an effect of preventing the photosensitive layer surface from scratches is also expected. Therefore, the properties desired for such a protective layer are low permeability of low molecular weight compounds such as oxygen and excellent mechanical strength, and further, transmission of light used for exposure is not substantially inhibited. It is desirable that it has excellent adhesiveness and can be easily removed in the development step after exposure.

  Such a device relating to the protective layer has been conventionally devised, and is described in detail in US Pat. No. 3,458,311 and JP-A-55-49729. As a material that can be used for the protective layer, for example, a water-soluble polymer compound having relatively excellent crystallinity is preferably used. Specifically, polyvinyl alcohol, polyvinyl pyrrolidone, acidic celluloses, gelatin, gum arabic, and polyacrylic are used. Water-soluble polymers such as acids are known, and among these, using polyvinyl alcohol as a main component gives the best results in terms of basic properties such as oxygen barrier properties and development removability. The polyvinyl alcohol used for the protective layer may be partially substituted with an ester, an ether and an acetal as long as it contains an unsubstituted vinyl alcohol unit for having necessary oxygen barrier properties and water solubility. Similarly, some of them may have other copolymer components. There is a preferred range for the coating amount of dry solids when applying such a protective layer, and it is preferable to form a dry solids coating amount in the range of 0.1 to 10 g per square meter on the photosensitive layer. Furthermore, the range of 0.2-2g is preferable. The protective layer is coated and dried on the photosensitive layer using various known coating methods.

  When applying the hydrophilic layer possessed by the photopolymerizable lithographic printing plate of the present invention, the photopolymerizable photosensitive layer provided thereon, the protective layer, or the like, the support is composed of the above-described elements. It is produced by applying and drying a coating liquid of the composition. As the coating method, various known methods can be used, and examples thereof include bar coater coating, slide hopper coating coating, curtain coating, blade coating, air knife coating, roll coating, spin coating, and dip coating. it can.

<Plate making method>
The plate making method of the photopolymerizable lithographic printing plate according to the present invention is the method of developing the photopolymerizable lithographic printing plate, and then the surface of the lithographic printing plate having the hydrophilic layer has a liquid absorption amount of the hydrophilic layer. Post-exposure is performed in a state containing water of 60% by mass or more. The water content of the surface having the hydrophilic layer of the lithographic printing plate is more preferably 80% by mass or more of the liquid absorption amount of the hydrophilic layer.

<Development processing>
The development process in the present invention means a process for removing a photosensitive layer that has not been cured by polymerization with a developer to expose the hydrophilic layer, and not only a processing step using the developer but also if necessary thereafter. Development process including the water washing step. For example, in the case of processing with a developer containing an alkaline agent having a pH of 9 or more, which will be described later, a water washing step is preferably provided following the development step, but even in this water washing step, it adheres to the hydrophilic layer surface. Since the photosensitive layer may be removed, in the present invention, the development process is performed including the water washing process. In addition, development with a developer that does not substantially contain an alkali agent as will be described later includes the case where the developer in the present invention is water because simple water can be used as the developer.

<Liquid absorption>
The liquid absorption amount of the hydrophilic layer in the present invention can be determined by measuring the liquid absorption amount of the hydrophilic layer before the photosensitive layer is applied, but the unexposed photopolymerizable lithographic printing plate is developed. The hydrophilic layer may be exposed and dried by the treatment, and then the liquid absorption amount of the hydrophilic layer may be measured and obtained. In the present invention, the liquid absorption amount of the hydrophilic layer is determined by placing the sample in 25 ° C. ion-exchanged water for 20 seconds, and then sandwiching the sample between filter papers for 3 seconds to remove the surface ion-exchanged water and weight the sample. It can be determined by measuring and removing the weight (dry mass) of the sample before being put into the ion exchange water from this weight. In addition, the amount of water contained in the surface having the hydrophilic layer before post-exposure is the weight of the sample immediately before post-exposure (immediately after passing through the liquid squeezing part for removing the washing water attached to the printing plate after washing). It can be determined by measuring the thickness and removing the dry mass of the sample from this weight. Moreover, it can also obtain | require using commercially available measuring instruments, such as the near-infrared moisture meter KJT-100 by Ketsu Scientific Research Institute.

<Developer>
The developer used for the development treatment may contain a surfactant or an alkali agent as necessary for the purpose of improving the image quality and shortening the development time. When the compound having a polymerizable double bond has an acidic group such as a carboxyl group or a sulfo group, and the acidic group is in the form of a metal salt or an amine salt in the photosensitive layer, it will be described later. It is possible to develop with a developer substantially not containing an alkali agent, that is, a neutral developer having a pH of less than 9. In particular, when the compound having a polymerizable double bond has a neutralized salt of a sulfo group, good developability can be obtained and elution with pure water is possible. If sufficient solubility cannot be obtained even with the sulfo group neutralized salt, a surfactant can be added to the neutral developer for the purpose of improving developability.

  Nonionic properties such as polyoxyethylene alkyl ethers, polyoxyethylene alkyl aryl ethers, polyoxyethylene alkyl esters, sorbitan alkyl esters, monoglyceride alkyl esters as surfactants, alkylbenzene sulfonates, alkylnaphthalene sulfonic acids Anionic surfactants such as salts, alkyl sulfates, alkyl sulfonates, sulfosuccinate esters, amphoteric surfactants such as alkyl betaines, amino acids, isopropyl alcohol, benzyl alcohol, ethyl cellosolve, butyl cellosolve, phenyl cellosolve, propylene glycol And water-soluble organic solvents such as diacetone alcohol.

  On the other hand, when the compound having a polymerizable double bond has an acid group that is not neutralized such as a carboxyl group or a sulfo group, the developer preferably contains an alkali agent. Alkaline agents include sodium silicate, potassium silicate, lithium silicate, ammonium silicate, sodium metasilicate, potassium metasilicate, sodium hydroxide, potassium hydroxide, lithium hydroxide, sodium carbonate, sodium bicarbonate, potassium carbonate, diphosphoric acid Inorganic alkali salts such as sodium, sodium triphosphate, dibasic ammonium phosphate, tribasic ammonium phosphate, sodium borate, potassium borate, ammonium borate, or monomethylamine, dimethylamine, trimethylamine, monoethylamine, diethylamine, triethylamine, monoisopropylamine , Diisopropylamine, monobutylamine, monoethanolamine, diethanolamine, triethanolamine, monoisopropanolamine, diisopropanolamine, etc. Is, they were added, can be used as an alkaline developing solution by adjusting to pH9 above. In addition, it is preferable to add the activator or the like used as the neutral developer to the alkali developer to improve the developability.

  The development is usually carried out by a known development method such as immersion development, spray development, brush development, ultrasonic development, etc., preferably at a temperature of about 10 to 60 ° C., more preferably about 15 to 45 ° C. for 5 seconds to It takes about 10 minutes. At that time, the protective layer provided as necessary on the photosensitive layer may be removed in advance with water or the like, or may be removed during development.

  Next, the plate making apparatus of the present invention will be described.

  A conventional plate making apparatus will be described with reference to FIGS. FIG. 3 is a schematic view showing an example of a conventional plate making apparatus.

  In FIG. 3, the leading end portion of the photopolymerizable planographic printing plate M on which an image is recorded by the exposure device 7 passes between the introduction guides 30 and 31 and enters the plate making device 9, and a pair of introduction rollers 11, 12. In the developing tank 48, the photopolymerizable lithographic printing plate M is immersed in the developing solution stored in the developing tank 48, and is moved downward in the figure by the conveying guide 49 and the guide roller 19 in the developing tank 48. Further, after passing through the guide roller 19, the traveling direction is changed to the upper right direction in the figure by the conveyance guide 49, and after passing through the pair of conveyance rollers 13 and 14 for stabilizing the conveyance performance, the scrub roller 70 and the scrub roller 70 It enters between the idle rollers 71 in contact with it, and the unexposed photosensitive layer is scraped off by the scrub roller 70. Thereafter, the developer attached to the front and back surfaces of the planographic printing plate M is squeezed out by a pair of squeezing rollers 15 and 16. Thereafter, the lithographic printing plate M is guided to the washing unit 2 and washed with washing water supplied from the shower pipe 52. The washing water adhering to the surface of the lithographic printing plate M is removed from the surface by the squeezing rollers 20 and 21, and the lithographic printing plate M passing between the squeezing rollers 20 and 21 is dried and conveyed to the post-exposure unit 3.

  FIG. 4 is a schematic diagram showing drying, a post-exposure part and a peripheral part in a conventional plate making apparatus. In FIG. 4, the lithographic printing plate M from which the rinsing water attached to the surface by the squeezing rollers 20 and 21 has been removed passes between the drying nozzles 65 and 66, and is dried between the conveying rollers 28 and 29. Is called. The drying process is performed by the hot air produced in the drying unit 27 passing through the duct 67 and being jetted from the drying nozzles 65 and 66 toward the planographic printing plate M. The lithographic printing plate M that has passed through the transport rollers 28 and 29 is discharged after being subjected to post-exposure processing in a post-exposure unit 40 having a post-exposure light source A. As described above, in the conventional plate-making method, it is common to post-expose the lithographic printing plate in a dry state.

  Next, the plate making apparatus of the present invention will be described. The plate making apparatus of the present invention is a plate making apparatus that performs post-exposure after developing the photopolymerizable lithographic printing plate after exposure, followed by a liquid squeezing part that removes moisture adhering to the printing plate after development processing, A plate making apparatus comprising a first drying processing unit having a light source for exposure. Here, as described above, the development process means a process of removing the photosensitive layer that has not been cured by polymerization with a developing solution to expose the hydrophilicity, and not only a processing step using the developing solution but also a necessity thereafter. It is set as the development process including the washing process performed according to it. Moreover, the case where the developer in the present invention is water is included.

  FIG. 1 is a schematic view showing an example of a plate making apparatus of the present invention. In FIG. 1, the leading end portion of the photopolymerizable planographic printing plate M on which an image is recorded by the exposure device 7 enters the plate making device 9 through between the introduction guides 30 and 31, and is introduced by a pair of introduction rollers 11 and 12. In the developing tank 48, the photopolymerizable lithographic printing plate M is immersed in the developing solution stored in the developing tank 48, and proceeds downward in the figure by the transport guide 49 and the guide roller 19 in the developing tank 48. After passing through the guide roller 19, the traveling direction is changed to the upper right direction in the drawing by the conveyance guide 49, and after passing through the pair of conveyance rollers 13, 14 for stabilizing the conveyance performance, the scrub roller 70 and the idol in contact with the scrub roller 70 It enters between the rollers 71, and the unexposed photosensitive layer is scraped off by the scrub roller 70. Thereafter, the developer attached to the front and back surfaces of the planographic printing plate M is squeezed out by a pair of squeezing rollers 15 and 16.

  Subsequently, the developed lithographic printing plate M is transported by the pair of transport rollers 17 and 18 through the crossing guide 32, and the surface of the lithographic printing plate M is placed from the inside of the rinsing bath 23 at the upper portion of the rinsing bath 23. It was washed with water washed by water pumped up by the circulation pump 53 and sprayed from the shower pipe 52, and then proceeded to the right in the figure by the transport guide 24, and then adhered to the front and back surfaces of the planographic printing plate M by the pair of squeezing rollers 20 and 21. The washing solution is squeezed out. Thus, the lithographic printing plate M is developed by processing in the water washing section 2.

  FIG. 2 is a schematic diagram showing the drying and post-exposure processing section and the peripheral section in the present invention. In FIG. 2, the lithographic printing plate M from which the washing water adhering to the surface by the squeezing rollers 20 and 21 has been removed is dried and conveyed to the post-exposure unit 3, having a fan 25 and a heater 26, passing through a duct 67, Drying is started by the drying mechanism 6 that blows hot air from the nozzles 65 and 66 to the photosensitive material M, and at the same time, post-exposure is performed by the post-exposure unit 40 having the post-exposure light source A. Discharged.

  1 and 2 show examples in which the squeezing rollers 20 and 21 are used as the liquid squeezing part for removing the water adhering to the printing plate after the development processing, the liquid squeezing part of the present invention is limited to this. For example, the washing water adhering to the surface of the lithographic printing plate M may be removed by pressing a flexible rubber blade against the surface of the lithographic printing plate M, or lithographic printing may be performed by blowing compressed air from the nozzle. The washing water adhering to the surface of the plate M may be removed. Further, as the post-exposure light source A included in the post-exposure unit 40, for example, a fluorescent lamp can be used in addition to the light sources described in Patent Documents 4 to 6 described above.

  EXAMPLES Hereinafter, although this invention is demonstrated using an Example, this invention is not limited by this description. In the following description, “%” and “part” are based on mass unless otherwise specified.

<Preparation of photopolymerizable lithographic printing plate>
A polyethylene terephthalate film having a thickness of about 200 μm was used as a substrate, and a hydrophilic layer coating solution 1 having the following composition was applied on the substrate by a slide hopper coating method. At that time, the moisture application amount was set in advance to be 35 g / m ² . Immediately after coating, the coating film was gelled with cold air of 1 to 5 ° C., and then dried using a dry air set at 50 ° C. After drying, a hydrophilic layer was provided on the substrate by putting it in a thermo-hygrostat adjusted to 40 ° C. and 40% RH and heating for 7 days.

<Hydrophilic layer coating solution 1>
Alkali-treated gelatin 1.2 parts Inorganic filler 1: Titanium dioxide 4.0 parts (TISR1, manufactured by Sakai Chemical Industry Co., Ltd., average primary particle size≈0.3 μm, relative refractive index≈2.04)
Inorganic filler 2: 1.6 parts of barium sulfate (B35, manufactured by Sakai Chemical Industry Co., Ltd., average primary particle size≈0.3 μm, relative refractive index≈1.23)
Inorganic filler 3: 0.4 parts of aluminum hydroxide (H42, manufactured by Showa Denko KK, average primary particle size ≈ 1.0 μm, relative refractive index ≈ 1.24)
Dispersant (acrylic acid copolymerized metal salt, 10% solution) 1.0 part Surfactant: Sodium polyoxyethylene tridecyl ether acetate (ECTD-3NEX, 10% solution manufactured by Nikko Chemicals Co., Ltd.) 0.4 part Hard Membrane agent (divinylsulfone, 5% solution) 4.0 parts The total amount was 35 parts with water.

  Regarding the particle size distribution and distribution frequency of the inorganic filler contained in the hydrophilic layer coating liquid 1, the inorganic fillers 2 and 3 contained in the hydrophilic layer coating liquid 1 are not added, but in the hydrophilic layer coating liquid. In addition, an inorganic filler 1 alone is prepared, and a coating liquid in which the inorganic fillers 2 and 3 are present alone in the hydrophilic layer coating liquid is prepared in the same manner. The particle size distribution and distribution frequency of the filler were measured using a laser diffraction / scattering type particle size distribution measuring apparatus (LA920 manufactured by Horiba, Ltd.), and the particle size distribution of each obtained single dispersion was multiplied by the addition ratio as a coefficient. The particle size distribution and distribution frequency of the hydrophilic layer coating solution 1 described above were calculated. As a result, the distribution frequency fx of the inorganic filler existing in the range of 0.2 μm or more and less than 0.6 μm is 64.8%, and the distribution frequency fy of the inorganic filler existing in the range of 0.6 μm or more and less than 1.5 μm is It was 30.1% and fx / fy was 2.15.

The amount of liquid absorbed by the hydrophilic layer obtained as described above was determined by placing the sample in 25 ° C. ion exchange water for 20 seconds and then sandwiching the sample between filter papers for 3 seconds to remove the ion exchange water on the surface. It was 1.7 g / m ² when the weight of the sample was measured and determined by removing the weight (dry mass) of the sample before being put into ion-exchanged water from this weight.

<Photosensitive layer>
On the hydrophilic layer obtained above, the following photopolymerizable photosensitive layer coating solution was applied so that the solid content was 1.5 g / m ^2, and dried for 10 minutes in a 75 ° C. drier after coating. did.

<Photopolymerizable photosensitive layer coating solution>
Sulfonic acid type polymer SP-2 (weight average molecular weight 400,000) 1.0 part Pentaerythritol tetraacrylate 0.5 part 3-acryloxypropyltrimethoxysilane 0.08 part Photopolymerization initiator BC-6 0.1 part Photopolymerization initiator T-8 0.1 part Sensitizer Following structure 0.05 part Colorant Pigment Blue 15 0.2 part Acetone 5.0 part Ethanol 5.0 part Tetrahydrofuran 10.0 part

<Protective layer>
A coating solution is prepared according to the following protective layer formulation, coated on the photosensitive layer obtained above so that the solid content is 1.5 g / m ^2, and dried for 10 minutes in a 75 ° C. drier after coating. And a photopolymerizable lithographic printing plate was obtained.

<Protective layer prescription>
Polyvinyl alcohol PVA-102 (manufactured by Kuraray Co., Ltd.) 1.0 part Ion exchange water 9.0 parts

<Exposure / Development>
The photopolymerizable lithographic printing plate obtained above was subjected to plate making using the plate making apparatus of the present invention shown in FIG. An exposure apparatus having a blue-violet semiconductor laser emitting at 405 nm (output 50 mW) as an exposure light source was used as the exposure apparatus 7, and the plate chart exposure energy was set to 200 μJ / cm ² to expose the test chart image. Thereafter, water was added to the developing layer 48 and the water-washing layer 23, and development was performed in the developing layer 48 at 25 ° C. for 15 seconds, followed by washing with water. The squeezing rollers 20 and 21 are used as a liquid squeezing part for removing water adhering to the printing plate after the development process after washing with water, and the amount of hot air supplied from the drying blast duct 67 and blown from the drying blast nozzles 65 and 66 is used. Is adjusted so that the moisture content on the surface having the hydrophilic layer of the lithographic printing plate M transported into the dried and post-exposed portion 3 is 1.7 g / m ² (in the liquid absorption amount of the hydrophilic layer). Containing 100% by weight of water, Example 1), 1.0 g / m ² (containing approximately 60% by weight of water with respect to the liquid absorption of the hydrophilic layer. Example 2), and 0.7 g / m It adjusted so that it might become m < ² > (about 40 mass% water | moisture content with respect to the liquid absorption amount of a hydrophilic layer. Comparative example 1). Thereafter, 20 fluorescent lamps “OSRAM DULUX L BLUE UVA 18W” manufactured by OSRAM were prepared as a post-exposure light source, and post-exposure was performed for 20 seconds under the condition that the distance from the printing plate was 5 cm. And the printing plate of Comparative Example 1 was obtained.

Furthermore, as Comparative Example 2, the photopolymerizable lithographic printing plate obtained above was subjected to plate making using the conventional plate making apparatus shown in FIG. An exposure apparatus having a blue-violet semiconductor laser emitting at 405 nm (output 50 mW) as an exposure light source was used as the exposure apparatus 7, and the plate chart exposure energy was set to 200 μJ / cm ² to expose the test chart image. Thereafter, water was added to the development layer 48 and the water-washing layer 23, and development was performed in the development layer 48 at 25 ° C. for 15 seconds, followed by washing with water. In addition, the moisture content of the surface having the hydrophilic layer of the printing plate that passed through the transport rollers 28 and 29 was 0% by mass with respect to the liquid absorption amount of the hydrophilic layer. Thereafter, 20 fluorescent lamps “OSRAM DULUX L BLUE UVA 18W” manufactured by OSRAM were prepared as a post-exposure light source, and 20 seconds of post-exposure was performed at a distance of 5 cm from the printing plate. Got a version.

  Using the printing plates of Examples 1 and 2 and Comparative Examples 1 and 2 thus obtained, the following evaluations were made for printing durability, ink detachment properties, and reticulation resistance by the following methods. .

<Print durability>
The printing machine uses an offset sheet-fed press Heidelberg QM46, the printing ink is New Champion F gloss ink H manufactured by DIC Corporation, and the dampening liquid is 1% of Astro Mark III manufactured by Nikken Chemical Laboratory. Printing was performed using the diluent. In the plate finishing, a gauge film was used, and the standard 200 μm was set to 300 μm (+100 μm). As an evaluation, the plate surface of the printing plate at the start and the plate surface of the printing plate after printing 10,000 sheets are compared, and the attenuation rate of the highlight halftone dot portion of 5 to 20% and the fine defect in the solid portion are observed. It was carefully observed with a 25-fold magnifier and judged using the following evaluation criteria. The results are shown in Table 1.
A: Almost no change is observed in the highlight part and the solid part.
○: Slight attenuation (within an attenuation rate of 10% or less) is observed in the highlight portion.
However, no defects are observed in the solid part.
Δ: A clear attenuation (attenuation rate of 10% or more) is observed in the highlight portion.
However, no defects are observed in the solid part.
X: The highlight part is attenuated by 50% or more.
Or abnormalities such as defects are observed in the solid portion.

<Ink detachability>
The printing machine uses an offset sheet-fed press Heidelberg QM46, high unity neo-soy red LZ made by Toyo Ink Co., Ltd. for printing ink, and Astro Mark III 1 made by Nikken Chemical Co., Ltd. Printing was performed using a% dilution. Note that the standard plate finishing was 200 μm. Regarding the printing method, printing was performed by first touching the ink foam roller twice on the plate surface before touching the water foam roller on the dry printing plate, and then touching the water foam roller simultaneously with paper feeding. The following criteria were used to evaluate ink detachment from the number of printed sheets required to completely eliminate stains on the printed paper surface. The results are shown in Table 1.
A: Less than 1 to 20 sheets completely eliminates stains on non-image areas.
A: Less than 20 to 50 sheets completely eliminates stains on the non-image area.
(Triangle | delta): The stain | pollution | contamination of a non-image part is eliminated completely by less than 50-100 sheets.
X: 100 or more sheets are required to completely remove non-image area contamination.

<Reticulation resistance>
In order to evaluate the ink detachability, after printing 500 sheets or more, the printer was temporarily stopped and only the blanket was washed. Thereafter, printing was carried out by a method of starting paper feeding after the water foam roller was again touched on the plate surface for 5 or more rotations as usual. For evaluation of the resistance to netting, the respective printing paper surfaces of the 2,000th sheet and the 5,000th sheet were observed and judged using the following evaluation criteria. The results are shown in Table 1.
A: No entanglement is observed even in shadow portions of 90% or more.
And there is no problem in reproducibility.
○: Slight entanglement is observed at halftone dots of 85% or more and less than 90%,
There is no problem in practical use.
(Triangle | delta): A tangle is recognized by the halftone dot part of 70% or more and less than 85%.
X: Tangle is observed at a halftone dot portion of less than 70%, and a problem is observed in reproducibility.

  As can be seen from Table 1, according to the present invention, it is understood that a plate making method of a photopolymerizable lithographic printing plate having excellent printing durability and improved problems such as ink detachability and network entanglement can be obtained. It can also be seen that the plate-making apparatus of the present invention is a plate-making apparatus that provides a printing plate that is excellent in printing durability and has improved problems such as ink detachability and screen entanglement.

DESCRIPTION OF SYMBOLS 1 Developing part 2 Water washing part 3 Drying, post-exposure part 6 Drying mechanism 7 Exposure apparatus 9 Plate-making apparatus 13, 14 Conveyance rollers 15, 16, 20, 21 Diaphragm roller 17 Conveyance roller 19 Guide roller 40 Post-exposure part 48 Developing tank 65, 66 Drying air nozzle 67 Drying air duct 70 Scrub roller 71 Idle roller M Photopolymerizable lithographic printing plate or lithographic printing plate A Post-exposure light source

Claims (2)

  A method for making a photopolymerizable lithographic printing plate having a hydrophilic layer on a substrate and having at least a photosensitive layer on the hydrophilic layer, the lithographic plate after developing the photopolymerizable lithographic printing plate A method for making a photopolymerizable lithographic printing plate, wherein the surface of the printing plate having the hydrophilic layer is post-exposed in a state containing water of 60% by mass or more of the liquid absorption amount of the hydrophilic layer. .   A plate-making apparatus for post-exposure after developing a photopolymerizable lithographic printing plate after exposure, and having a light source for post-exposure following a liquid squeezing portion that removes water adhering to the lithographic printing plate after development processing A plate making apparatus having a first drying processing section.

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