JP2020026136A - Original plate of lithographic printing plate, method for manufacturing lithographic printing plate and method for manufacturing printed matter using the same - Google Patents

Abstract

To provide an original plate of a lithographic printing plate which is excellent in sensitivity, has silicone-resistant peeling, and has good plate inspection even in the case of chemical-free development, and to provide a method for manufacturing a lithographic printing plate using the same and a method for manufacturing a printed matter using the same.SOLUTION: An original plate of a lithographic printing plate has, on a substrate, a thermosensitive layer containing an infrared absorbing compound, and an ink-repellent layer in this order, in which a difference between concentration of reflected light measured from the top of the ink-repellent layer and concentration of reflected light measured only from the thermosensitive layer is 0.3-1.5.SELECTED DRAWING: None

Description

  The present invention relates to a lithographic printing plate precursor used for lithographic printing, a method for producing a lithographic printing plate, and a method for producing a printed matter using the same.

  Lithographic printing is a printing method characterized by using a printing plate without unevenness, unlike a relief printing method using a printing plate having unevenness. In lithographic printing with water, a non-image portion is formed by a dampening solution supplied to the printing plate during printing, and when the oil-based printing ink composition is supplied thereafter, the printing ink composition is repelled by the dampening solution. A print image is formed. On the other hand, in waterless lithographic printing, a non-image area is formed with a silicone resin, and when a printing ink composition that repels the silicone composition is supplied thereto, the printing ink composition is repelled and the printing ink composition becomes lipophilic. Adheres only to the image portion of. Thus, an image is formed on the surface of the printing plate, and printing is performed by transferring the image to the blanket and the paper sequentially.

  The waterless lithographic printing plate precursor used in the waterless lithographic printing is roughly classified into an ablation type in which the heat-sensitive layer is ablated and removed at the time of exposure, and a non-ablation type in which the heat-sensitive layer remains even after the exposure step. You. In the ablation type, since the heat-sensitive layer is removed, it is possible to provide a contrast difference between the image area and the non-image area by including a colored dye in the heat-sensitive layer. Therefore, there is an advantage that plate inspection can be performed without a step of dyeing an image area using a solution containing a dye (dyeing step). However, there has been a problem that a large amount of ablation residues are generated during exposure.

  On the other hand, the non-ablation type is preferable because an abrasion scum is hardly generated at the time of exposure, so that the risk of contamination in the exposure apparatus is low. On the other hand, since the heat-sensitive layer remains in both the image portion and the non-image portion, the contrast difference between the image portion and the non-image portion is small. For this reason, it has been practiced to impart a plate inspection property by providing a dyeing step at the time of development. However, in recent years, there has been an increasing demand for chemical-free development that does not include a dyeing step due to increased environmental awareness. Therefore, when a non-ablation type lithographic printing plate precursor is developed without using a dyeing step, there is a problem that sufficient plate inspection properties cannot be obtained.

  To address this problem, Patent Document 1 discloses that a heat-sensitive layer of a direct-drawing waterless printing plate precursor contains a substance that dissolves or swells in water, so that the heat-sensitive layer after exposure contains water or water as a main component. Dissolved and removed with liquid. As a result, in the image area, the primer layer or the substrate located under the heat-sensitive layer is exposed, so that an attempt is made to improve plate inspection.

  Further, in Patent Document 2, the heat-sensitive layer of a direct-drawing waterless printing plate precursor contains a composition obtained by mixing a coloring agent that develops a color by the action of an acid and a thermal acid generator, thereby generating the laser-irradiated portion. The heat generated generates an acid, causing the pigment to develop color. In this way, the heat-sensitive layer in the image area is discolored, and an attempt is made to improve the plate inspection.

  Patent Document 3 discloses that a color pigment is contained in an ink repellent layer (silicone rubber layer) of a lithographic printing plate precursor without water, so that a color of a heat-sensitive layer exposed in an image portion and a silicone exposed in a non-image portion are provided. Because the color of the rubber layer is different, a contrast difference between an image portion and a non-image portion is obtained, and an attempt is made to improve plate inspection.

JP-A-10-250253 JP 2001-51409 A JP 2011-34114 A

  However, in the method described in Patent Document 1, in which the heat-sensitive layer contains a substance that dissolves or swells in water, the heat-sensitive layer present in the non-image area also has the property of dissolving or swelling in water. There was a risk of "silicone peeling" in which the ink repellent layer (silicone rubber layer) was peeled off unintentionally. Furthermore, since carbon black as a pigment is used as a light-to-heat conversion material, the sensitivity of a lithographic printing plate precursor was not always sufficient.

  Further, in a method described in Patent Document 2, in which a heat-sensitive layer contains a composition obtained by mixing a dye and a acid which develop a color by the action of an acid, coloring of the dye occurs only on the surface of the heat-sensitive layer. As a result, a low-density color was formed, and a contrast sufficient for the purpose of plate inspection was not obtained.

  Further, in the method described in Patent Document 3 in which a colored pigment is contained in an ink repellent layer (silicone rubber layer), the colored pigment may hinder the purpose of repelling the ink. Cannot be increased, and the pigment has a low coloring power, so that a contrast sufficient for plate inspection has not been obtained.

  Therefore, an object of the present invention is to provide a lithographic printing plate precursor that has excellent sensitivity, hardly causes silicone peeling, and has good plate inspection even when applying chemical-free development without using a dyeing process. .

  The present invention provides a lithographic printing plate precursor having, on a substrate, at least a heat-sensitive layer containing an infrared absorbing compound and an ink repellent layer in this order, and a lithographic printing plate obtained by exposing and developing the lithographic printing plate precursor. The lithographic printing plate precursor, wherein the difference between the reflected light density of the unexposed portion and the reflected light density of the exposed portion, which is required on the exposed surface side, is 0.3 to 1.5. The present invention is intended to provide various improved inventions and inventions utilizing these inventions.

  According to the present invention, it is possible to obtain a lithographic printing plate precursor in which good plate inspection properties can be realized even when chemical-free development without using a dyeing step is applied, and which is excellent in sensitivity and in which silicone peeling is suppressed. it can.

  The lithographic printing plate precursor according to the invention will be described below.

  The lithographic printing plate precursor according to the invention is at least a heat-sensitive layer containing an infrared absorbing compound on a substrate, and a lithographic printing plate precursor having an ink repellent layer in this order, by exposing and developing the lithographic printing plate precursor. The obtained planographic printing plate is characterized in that the difference between the reflected light density of the unexposed portion and the reflected light density of the exposed portion, which is required on the exposed surface side, is 0.3 to 1.5. The lithographic printing plate precursor according to the invention refers to a lithographic printing plate precursor in which the heat-sensitive layer remains on the lithographic printing plate when exposed and developed, from the viewpoint of not generating abrasion scum at the time of exposure. The heat-sensitive layer remains in a solid image in which the reflected light density of the exposed portion is measured when the reflected light density difference is evaluated as described in the section.

  Although the details of the heat-sensitive layer will be described later, the infrared-absorbing compound contained in the layer has a function of converting light into heat when irradiated with actinic rays, and a chemical or physical change caused by the generated heat. Is a layer having an effect of causing a change in adhesion or adhesion to an adjacent layer.

  The ink repelling layer, which will be described in detail later, has a function of discharging the printing ink from above the layer when the printing ink is applied by containing a substance having a property of repelling the printing ink. It is.

  When the laser light is applied, the laser light passes through the ink repellent layer, and the infrared absorbing compound in the heat-sensitive layer absorbs the laser light and generates heat by a photothermal conversion effect. This heat generation causes dissociation between the heat-sensitive layer and the ink repellent layer, that is, a decrease in the adhesive strength or adhesion between the layers. The printing plate can be obtained by removing the ink repellent layer at the portion exposed in the developing step.

  The lithographic printing plate precursor of the present invention is a lithographic printing plate obtained by exposing and developing the lithographic printing plate precursor, wherein on the exposed surface side, the reflected light density of the unexposed portion and the reflected light density of the exposed portion are determined. The difference is between 0.3 and 1.5. If this difference is less than 0.3, the contrast between the image portion and the non-image portion is not sufficient, and thus the plate inspection property is insufficient. From the viewpoint of providing a lithographic printing plate precursor having good plate inspection properties, the difference in the reflected light density is preferably 0.5 or more, more preferably 0.7 or more, and 0.9 or more. Is more preferable, and even more preferably 1.2 or more. Further, when the difference in the reflected light density exceeds 1.5, although the plate inspection property is at a sufficient level, there is a possibility that the developing property, the sensitivity and the silicone peeling resistance may be affected, It is disadvantageous in terms of economy.

  In the lithographic printing plate precursor of the present invention, in the lithographic printing plate obtained by exposing and developing the lithographic printing plate precursor, on the exposed surface side, the reflected light density of the unexposed portion and the reflected light density of the exposed portion are determined. The difference is determined according to the method described in the Examples section. Normally, the unexposed portion does not change or deteriorate in the exposure step, and the reflected light density of the unexposed portion may be the same as that of the original plate (that is, the plate before exposure). In addition, in the state where the plate material is as it is, if it does not reach the CTP exposure machine or the developing machine described in the section of the examples, the size can be adjusted appropriately as described above. It is needless to say that it can be determined using an exposure machine or a developing machine.

  The lithographic printing plate precursor according to the invention is preferably a layer that does not contain an infrared absorbing compound and contains a dye compound between the heat-sensitive layer and the ink repellent layer (this layer may be referred to as a “colored layer” hereinafter). ). Where the colored layer contains a dye compound, the colored layer is removed together with the ink repellent layer in the developing step to obtain a contrast difference between the unexposed portion and, in particular, the reflection of the unexposed portion described above. The difference between the light density and the reflected light density of the exposed portion can be easily set to 0.3 to 1.5. On the other hand, if the colored layer contains an infrared absorbing compound, the radiation energy to the heat-sensitive layer will be absorbed, so that the sensitivity may be lowered. A more detailed description of the colored layer will be described later.

  The substrate that can be used in the lithographic printing plate precursor of the present invention is not particularly limited in terms of its material as long as it can support the heat-sensitive layer and the ink repellent layer. Paper, metal, glass, film, and the like, which are well-known materials with little change, can be used. Specifically, paper, paper laminated with plastic (polyethylene, polypropylene, polystyrene, etc.), metal plates such as aluminum (including aluminum alloys), zinc, copper, etc., glass plates such as soda lime, quartz, silicon wafers, Examples thereof include plastic films such as cellulose acetate, polyethylene terephthalate, polyethylene, polyester, polyamide, polyimide, polystyrene, polypropylene, polycarbonate, and polyvinyl acetal, and paper or plastic films on which the above-described metals are laminated or vapor-deposited. The plastic film may be transparent or opaque. From the viewpoint of plate inspection, an opaque film is preferable.

  Among these substrates, an aluminum plate is particularly preferable because it has little dimensional change in the printing process and is inexpensive. As a flexible substrate for light printing, a polyethylene terephthalate film is particularly preferable.

  The thickness of the substrate is not particularly limited, and a thickness corresponding to a printing machine used for lithographic printing may be selected.

  In the lithographic printing plate precursor according to the invention, an underlayer can be provided between the heat-sensitive layer and the substrate. This underlayer can be used for the purpose of imparting flexibility to the lithographic printing plate precursor and having good adhesion to the substrate or the heat-sensitive layer. For example, JP-A-2004-199016, JP-A-2004-33425 And a layer containing a metal chelate compound disclosed in Japanese Unexamined Patent Publication (Kokai) No. H10-15095.

  The underlayer may be a layer containing a flexibility-imparting agent such as polyurethane resin, natural rubber, or synthetic rubber for the purpose of imparting flexibility and controlling scratch resistance. Among these softening agents, it is particularly preferable to use a polyurethane resin from the viewpoint of coating performance and coating liquid stability.

  Further, the underlayer may be a layer containing an active hydrogen group-containing compound for the purpose of improving the adhesion between the substrate and the thermosensitive layer. Examples of the active hydrogen group-containing compound include a hydroxyl group-containing compound, an amino group-containing compound, a carboxyl group-containing compound, a thiol group-containing compound, and the like.A hydroxyl group-containing compound is preferable, and an epoxy resin is particularly preferable from the viewpoint of adhesion to a substrate. It is preferably used.

  Further, the underlayer can be a layer containing a pigment. By including an appropriate pigment, the light transmittance of the printing plate can be reduced to 15% or less for all wavelengths of 400 to 650 nm, thereby providing plate inspection by machine reading. it can. As the pigment, it is preferable to use inorganic white pigments such as titanium oxide, zinc white, and lithopone, and inorganic yellow pigments such as graphite, cadmium yellow, yellow iron oxide, ocher, and titanium yellow. Among these pigments, titanium oxide is particularly preferred in terms of hiding power and coloring power.

  Next, the heat-sensitive layer will be described focusing on aspects that can be preferably used in the present invention.

  The heat-sensitive layer can be preferably formed by a coating method. That is, it can be formed by dissolving or dispersing an infrared absorbing compound and a component such as a binder holding the compound in a solvent, coating and drying (removing volatile components). Drying may be performed at normal temperature or by heating.

In the present invention, the term “infrared absorbing compound” refers to a compound having a maximum absorption wavelength (λ _max ) in a wavelength range of 750 to 1,200 nm and a molar extinction coefficient ε at λ _max of 1 × 10 ³ L / (mol · cm) or more. Means the compound of As an infrared absorbing compound, it absorbs laser light, converts light energy to kinetic energy of atoms and molecules, instantaneously generates heat of 200 ° C or more on the surface of the thermosensitive layer, and thermally decomposes the crosslinked structure of the thermosensitive layer. The one having the function to perform is preferable. For example, cyanine dye, azulenium dye, squarylium dye, croconium dye, azo disperse dye, bisazostilbene dye, naphthoquinone dye, anthraquinone dye, perylene dye, phthalocyanine dye, naphthalocyanine metal complex Dyes such as dyes, polymethine dyes, dithiol nickel complex dyes, indoaniline metal complex dyes, intermolecular CT dyes, benzothiopyran spiropyrans, and nigrosine dyes are preferably used.

Among them, those having a particularly large molar extinction coefficient ε are preferably used. Specifically, ε is preferably 1 × 10 ⁴ L / (mol · cm) or more, and more preferably 1 × 10 ⁵ L / (mol · cm) or more. If ε is 1 × 10 ⁴ L / (mol · cm) or more, the initial sensitivity can be further improved. The coefficient here is for the active energy ray to be irradiated. If a specific wavelength is indicated, attention should be paid to 780 nm, 808 nm, 830 nm, or 1064 nm. Two or more dyes may be contained in the heat-sensitive layer. By containing two or more dyes having different λ _max in the wavelength range of 750 to 1,200 nm, it is possible to cope with two or more lasers having different oscillation wavelengths.

  The content of the infrared-absorbing compound contained in the heat-sensitive layer is preferably 10% by mass or more when the mass of the heat-sensitive layer containing the infrared-absorbing compound is 100% by mass. By setting the content of the infrared absorbing compound to 10% by mass or more, the sensitivity at the time of laser irradiation can be further improved. The content of the infrared absorbing compound is more preferably at least 12% by mass. On the other hand, the content of the infrared absorbing compound is preferably 30% by mass or less, more preferably 20% by mass or less. With such a range, the solvent resistance can be improved.

The heat-sensitive layer may contain, as a component other than the infrared absorbing compound, for example, a binder component holding the infrared absorbing compound. The heat-sensitive layer has a function of converting laser light used for drawing into heat (light-to-heat conversion), and the generated heat efficiently decomposes at least the surface of the heat-sensitive layer, or increases the solubility in the developer. Is preferable. From such a viewpoint, examples of the material constituting the heat-sensitive layer include the following compositions (1) and (2) and those in which all or some of the components in the composition have reacted.
(1) A composition comprising a polymer having active hydrogen, a polyfunctional compound, and an infrared absorbing compound.
(2) A composition containing a polymer having active hydrogen, an organic complex compound, and an infrared absorbing compound.

  Here, in the composition shown in (1), irradiation with light causes decomposition of a crosslinked structure composed of a polymer having active hydrogen and a polyfunctional compound. In the composition shown in (1), the cross-linking structure composed of the polymer having active hydrogen and the organic complex compound is decomposed by irradiation with light, and the function as a heat-sensitive layer is effectively exhibited. It is possible. Further, the composition shown in the above (1) may further contain an organic complex compound.

  The heat-sensitive layer may contain a dye compound, but does not have to contain it.

Examples of the polymer having active hydrogen which is preferably used for the heat-sensitive layer include a polymer having a structural unit having active hydrogen. The structural unit having an active hydrogen for _{example, -OH, -SH, -NH 2,} -NH -, - CO-NH 2, -CO-NH -, - OC (= O) -NH -, - NH-CO -NH -, - CO-OH, -CS-OH, -CO-SH, -CS-SH, -SO 3 H, -PO 3 H 2, -SO 2 -NH 2, -SO 2 -NH -, - _CO-CH 2 -CO- and the like.

  Examples of the polymer having active hydrogen which can be preferably used in the compositions (1) and (2) include a homopolymer or a copolymer of a monomer having a carboxyl group such as (meth) acrylic acid, and hydroxyethyl (meth) acrylate. ) Homopolymers or copolymers of (meth) acrylates containing hydroxyl groups such as acrylates and 2-hydroxypropyl (meth) acrylates, homopolymers or copolymers of N-alkyl (meth) acrylamide and (meth) acrylamide Ethylene having active hydrogen such as a homopolymer or copolymer of a polymer, a reaction product of amines with glycidyl (meth) acrylate or allyl glycidyl, and a homopolymer or copolymer of p-hydroxystyrene and vinyl alcohol Homopolymer or copolymer of copolymerizable unsaturated monomer (copolymer) The case monomer component may be another ethylenically unsaturated monomer having an active hydrogen, it may be ethylenically unsaturated monomers containing no active hydrogen.) And the like. These may contain two or more kinds.

  Further, as a polymer having a structural unit having active hydrogen, a polymer having a structural unit having active hydrogen in the main chain is also preferably used. Examples of such polymers include polyurethanes, polyureas, polyamides, epoxy resins, polyalkylene imines, melamine resins, novolak resins, resole resins, cellulose derivatives, and the like. Two or more of these may be contained.

  As the polymer having active hydrogen, a polymer having an alcoholic hydroxyl group, a phenolic hydroxyl group, and a carboxyl group is preferable, and a polymer having a phenolic hydroxyl group (p-hydroxy Styrene homopolymers or copolymers, novolak resins, resol resins, etc.) are more preferred, and novolak resins are even more preferred. Novolak resins include phenol novolak resins and cresol novolak resins.

  The content of the polymer having active hydrogen contained in the heat-sensitive layer is preferably 20% by mass or more, and more preferably 40% by mass or more when the mass of the heat-sensitive layer is 100% by mass, from the viewpoint that the developability can be improved. It is more preferably 80% by mass or less, and more preferably 70% by mass or less, from the viewpoint of ensuring sufficient toughness of the heat-sensitive layer.

  Examples of the polyfunctional compound preferably used in the heat-sensitive layer, particularly the polyfunctional compound used in the composition shown in the above (1), include compounds having a plurality of functional groups reactive with active hydrogen. It can function as a crosslinking agent to a polymer having hydrogen. For example, polyfunctional isocyanate, polyfunctional blocked isocyanate, polyfunctional epoxy compound, polyfunctional (meth) acrylate compound, polyfunctional aldehyde, polyfunctional mercapto compound, polyfunctional alkoxysilyl compound, polyfunctional amine compound, polyfunctional carboxylic acid, Examples include a polyfunctional vinyl compound, a polyfunctional diazonium salt, a polyfunctional azide compound, and hydrazine.

  The organic complex compound preferably used for the heat-sensitive layer, in particular, the organic complex compound used for the composition shown in the above (2) comprises a metal and an organic compound coordinated or bonded to the metal. Can function as a crosslinking agent for a polymer having For example, an organic complex salt in which an organic ligand is coordinated with a metal, an organic-inorganic complex salt in which an organic ligand and an inorganic ligand are coordinated with a metal, and a metal alkoxide in which a metal and an organic molecule are covalently bonded via oxygen. And the like. Among these, a metal chelate compound in which a ligand has two or more donor atoms and forms a ring containing a metal atom, the stability of the organic complex compound itself and the stability of the heat-sensitive layer composition solution It is preferably used from the viewpoint of.

  The main metals forming the organic complex compound are Al (III), Ti (IV), Mn (II), Mn (III), Fe (II), Fe (III), Zn (II), Zr (IV Is preferred. Al (III) is particularly preferable in that the effect of improving sensitivity is easily obtained, and Ti (IV) is particularly preferable in that resistance to a printing ink or an ink detergent is easily developed.

Examples of the ligand include a compound having a coordination group having oxygen, nitrogen, sulfur, or the like as a donor atom. Specific examples of the coordinating group include those having oxygen as a donor atom such as -OH (alcohol, enol and phenol), -COOH (carboxylic acid),> C = O (aldehyde, ketone, quinone), -O Examples of those having nitrogen as a donor atom, such as-(ether), -COOR (ester, R: represents an aliphatic or aromatic hydrocarbon), -N = O (nitroso compound), include -NH ₂ (primary) Amine, hydrazine),> NH (secondary amine),> N- (tertiary amine), -N = N- (azo compound, heterocyclic compound), = N-OH (oxime), etc. Include -SH (thiol), -S- (thioether),> C = S (thioketone, thioamide), = S- (heterocyclic compound), and the like.

  Among the organic complex compounds formed from a metal and a ligand as described above, compounds preferably used are Al (III), Ti (IV), Fe (II), Fe (III), Zn (II) , Zr (IV) and other complex compounds of metals such as β-diketones, amines, alcohols, and carboxylic acids. Al (III), Fe (II), Fe (III), Ti (IV) ), An acetylacetone complex of Zr (IV), an acetoacetate ester complex and the like are particularly preferred complex compounds. Specific examples include aluminum tris (acetylacetonate), aluminum tris (ethylacetoacetate), aluminum tris (propylacetoacetate), aluminum bis (ethylacetoacetate) mono (acetylacetonate), and aluminum bis (acetylacetonate). Mono (ethyl acetoacetate), aluminum bis (propyl acetoacetate) mono (acetylacetonate), aluminum bis (butyl acetoacetate) mono (acetylacetonate), aluminum bis (propyl acetoacetate) mono (ethyl acetoacetate), aluminum Dibutoxide mono (acetylacetonate), aluminum diisopropoxide mono (acetylacetonate), aluminum diisopropoxide (Ethyl acetoacetate), aluminum-s-butoxide bis (ethyl acetoacetate), aluminum di-s-butoxide mono (ethyl acetoacetate), titanium triisopropoxide mono (allyl acetoacetate), titanium diisopropoxide bis ( Triethanolamine), titanium di-n-butoxide bis (triethanolamine), titanium diisopropoxide bis (acetylacetonate), titanium di-n-butoxide bis (acetylacetonate), titanium diisopropoxide bis ( Ethyl acetoacetate), titanium di-n-butoxide bis (ethyl acetoacetate), titanium tri-n-butoxide mono (ethyl acetoacetate), titanium triisopropoxide mono (meth Acryloxyethyl acetoacetate), titanium dihydroxybis (lactate), zirconium di-n-butoxide bis (acetylacetonate), zirconium tri-n-propoxide mono (methacryloxyethyl acetoacetate), zirconium tetrakis (acetylacetonate) , Iron (III) acetylacetonate and iron (III) benzoylacetonate. These may contain two or more kinds.

  As the content of the organic complex compound in the thermosensitive layer, from the viewpoint of the function of the polymer as a crosslinking agent and the solvent resistance of the thermosensitive layer, when the mass of the thermosensitive layer is 100% by mass, 1% by mass or more, It is preferable that the content be 40% by mass or less.

  The heat-sensitive layer may contain, in addition to the polymer having active hydrogen, a polymer having no active hydrogen and having a film forming ability. Such a polymer is preferably used for the purpose of improving the mechanical properties of the heat-sensitive layer or improving the coatability when forming the heat-sensitive layer by a coating method. Examples thereof include polymethyl (meth) acrylate and polybutyl (meth) acrylate. Homopolymers or copolymers of (meth) acrylates, homopolymers or copolymers of styrene monomers such as polystyrene and α-methylstyrene, various synthetic rubbers such as isoprene and styrene-butadiene, and polyacetic acid Examples thereof include homopolymers such as vinyl esters such as vinyl, copolymers such as vinyl acetate-vinyl chloride, and various condensed polymers such as polyester and polycarbonate.

  From the viewpoint of coatability of the thermosensitive layer composition solution, the polymer having no active hydrogen is preferably at least 3.5 mass%, more preferably at least 100 mass%, more preferably at least 100 mass%. It is preferably at least 7.5% by mass, more preferably at most 40% by mass, more preferably at most 20% by mass, from the viewpoint of improving the image reproducibility of the lithographic printing plate with high definition.

  Next, the colored layer will be described focusing on aspects that can be preferably used in the present invention.

The colored layer does not contain an infrared absorbing compound, while it contains a dye compound. The meaning of the infrared absorbing compound here is the same as the infrared absorbing compound described for the heat-sensitive layer. In addition, the meaning of not containing means that it is not substantially contained, and specifically, even if there is no detection or migration from the thermosensitive layer due to diffusion phenomenon, etc., the colored layer Is about 0.1% by mass or less with respect to the mass of 100% by mass. The dye compound is a compound having a maximum absorption wavelength (λ _max ) at 250 nm to 700 nm and a compound having a molar extinction coefficient ε at λ _max of 1.0 × 10 ⁴ L / (mol · cm) or more. That means.

  Specific examples of the coloring compound include monoazo dyes, polyazo dyes, metal salt azo dyes, stilbene azo dyes, pyrazolone azo dyes, thiazole azo dyes, anthraquinone dyes, anthrone dyes, indigo dyes, thioindigo dyes, phthalocyanine dyes, and naphthalocyanine dyes. , Diphenylmethane dye, triphenylmethane dye, xanthene dye, acridine dye, azine dye, oxazine dye, thiazine dye, polymethine dye, azomethine dye, quinoline dye, nitro dye, nitroso dye, benzoquinone dye, naphthoquinone dye, naphthalimide dye, verinone Dyes, vitamins and the like can be mentioned, and among them, those satisfying the above requirements can be used. In the present invention, two or more of these compounds can be used.

Among these, it is preferable to use a dye having λ _max at 400 nm to 600 nm as the dye compound contained in the colored layer. The colored layer containing such a dye compound is likely to exhibit a red color, while many infrared absorbing compounds exhibit a green color. Can be effectively increased in reflected light density. Therefore, the difference between the reflected light density of the unexposed portion and the reflected light density of the exposed portion can be efficiently increased, and a better plate inspection property is obtained, which is preferable. Specific examples of such a coloring compound include methyl orange, methyl yellow, Congo red, chlorophenol red, phenol red, cresol red, basic violet 14, rhodamine 6G, and the like.

  Further, the dye compound more preferably has a property of being thermally decomposed without undergoing melting. The property of thermally decomposing without undergoing melting refers to a property in which a melting peak is not observed before a weight loss is observed in a temperature range of 100 ° C. or higher. It can be determined by performing DTA measurement. The detailed method will be described in the examples section. When the coloring compound has a property of being thermally decomposed without undergoing melting, it is possible to improve the sensitivity of the lithographic printing plate precursor. That is, it is preferable because the exposure step can be performed with a smaller laser output. This is because the dye compound, which has the property of decomposing without undergoing melting, absorbs heat and does not use the absorbed heat for its own melting state change, but uses it efficiently for pyrolysis. Is considered to promote the dissociation between the heat-sensitive layer and the colored layer by the gas generated by the heat treatment. In addition, since such a property facilitates the removal of the colored layer together with the removal of the ink repellent layer in the developing step, it is advantageous in increasing the difference between the reflected light density of the unexposed portion and the reflected light density of the exposed portion.

  Specific examples of the coloring compound having this property include basic fuchsin, light green SF yellow, basic red 9, cresol red, malachite green oxalate, brilliant green, Victoria blue B, crystal violet, bromocresol purple, and bromocresol Triphenylmethane dyes such as green sodium, thymol blue, bromocresol green, bromothymol blue sodium, tetrabromophenol blue and bromothymol blue; thiazine dyes such as methylene blue; azo dyes such as Congo-Red, Oil Red 5B and methyl yellow , Rhodamine B, rhodamine 6G, fluorescein, fluorescein-5-maleimide, fluorescein isothiocyanate, diiodofluorescein, Xanthene dyes such as chloro fluorescein, vitamins such as riboflavin and the like. Among these, it is preferable to use at least one compound selected from the group consisting of a triphenylmethane dye, a thiazine dye, an azo dye, and a xanthene dye. Further, among the xanthene dyes, it is preferable to use a fluorescein compound.

  It is preferable that the coloring compound is contained in the colored layer in an amount of 5% by mass or more when the mass of the coloring layer containing the coloring compound is 100% by mass. By setting the content of the dye compound to 5% by mass or more, in the lithographic printing plate obtained by exposing and developing the lithographic printing plate precursor, the reflected light density of the unexposed portion, which is required on the exposed surface side, and the The difference from the reflected light density can be made sufficiently large, and better plate inspection can be provided. The content of the coloring compound is more preferably 10% by mass or more, and further preferably 15% by mass or more. On the other hand, when the content of the coloring compound is 50% by mass or less, the film strength of the colored layer can be maintained, the solvent resistance of the lithographic printing plate can be increased, and peeling of silicone can be suppressed. The content of the coloring compound is more preferably 40% by mass or less in the colored layer, and further preferably 30% by mass or less in the colored layer.

  The colored layer can be preferably formed by a coating method. That is, it can be formed by dissolving or dispersing a dye compound and components such as a binder holding the dye compound in a solvent, and applying and drying (removing volatile components). Drying may be performed at normal temperature or by heating.

  The colored layer can contain, for example, a binder component holding the dye compound as a component other than the dye compound. Further, a polymer containing active hydrogen can be preferably contained, and the polymer containing active hydrogen can also function as a binder component. Here, the meaning of the polymer containing active hydrogen is the same as the polymer containing active hydrogen described for the thermosensitive layer. Above all, it is more preferable to use at least one resin selected from melamine resins, novolak resins and resole resins, since the adhesion to the heat-sensitive layer or the ink repellent layer can be improved. The inclusion of such a polymer containing active hydrogen is advantageous in that the adhesiveness to the heat-sensitive layer or the ink repellent layer can be improved due to high reactivity, and silicone peeling can be suppressed.

  Further, the colored layer may preferably contain a polyfunctional compound or an organic complex compound. Here, the meanings of the polyfunctional compound and the organic complex compound are the same as those described in the description of the heat-sensitive layer, respectively, and the polyfunctional compound and the heat-sensitive layer composition (1) contained in the composition (1) of the heat-sensitive layer. At least one of the organic complex compounds contained in 2) can be used. The inclusion of such a compound is advantageous in that a crosslinked structure is formed in the colored layer, solvent resistance can be increased, and peeling of silicone can be suppressed. The content of the polyfunctional compound or the organic complex compound is 1% by mass or more when the mass of the colored layer is 100% by mass, from the viewpoint of maintaining the crosslink density of the colored layer high and suppressing silicone peeling in the lithographic printing plate. It is preferably 30% by mass or less from the viewpoint that the sensitivity of the lithographic printing plate can be kept high.

Further, the colored layer may preferably contain a non-dye compound having a property of thermally decomposing without undergoing melting. Here, the meaning of the property of thermally decomposing without melting is the same as the meaning described in the description of the dye compound, and the non-dye compound means the molar extinction coefficient at all wavelengths in the wavelength range of 250 nm to 1,200 nm. It is a compound in which ε is less than 1.0 × 10 ³ L / (mol · cm). The inclusion of such a compound is advantageous in that sensitivity to laser light is increased and development can be performed with a smaller laser output.

  Specific examples of the non-dye compound having the property of thermally decomposing without undergoing such melting include flavonoids such as catechin hydrate, vitamins such as ascorbic acid, and cellulose derivatives such as ethyl cellulose and nitrocellulose. Among these, vitamins and cellulose derivatives are preferred.

  The thickness of the colored layer is determined by the difference between the reflected light density of the unexposed portion and the reflected light density of the exposed portion, which is determined on the exposed surface side of the lithographic printing plate obtained by exposing and developing the lithographic printing plate precursor. Is preferably 0.5 μm or more, more preferably 0.8 μm or more, and still more preferably 1.0 μm or more, from the viewpoint of obtaining a sufficient value of the particle size and maintaining the silicone peeling resistance in a high state. Further, from the viewpoint that the sensitivity of the lithographic printing plate can be kept high and the laser output required in the exposure step can be kept low, it is preferably 3.0 μm or less, more preferably 2.5 μm or less, and still more preferably 2.0 μm or less. Here, the thickness of the colored layer can be determined by observing the cross section with a transmission electron microscope. More specifically, the thickness can be measured by preparing a sample from the lithographic printing plate precursor by the ultra-thin section method and observing the sample under the conditions of an acceleration voltage of 100 kV and a direct magnification of 10 k times. The average film thickness can be determined by measuring the film thickness at 10 locations randomly selected from the colored layers and calculating the number average value.

  Next, the ink repellent layer will be described focusing on aspects that can be preferably used in the present invention.

  As a material suitably used for the ink repellent layer, a silicone rubber which is a crosslinked product of a polyorganosiloxane is exemplified. Examples of the silicone rubber include an addition reaction type silicone rubber and a condensation reaction type silicone rubber. These solutions or dispersions can be applied and dried to form an ink repellent layer.

  The addition reaction type silicone rubber layer composition preferably contains at least a vinyl group-containing organopolysiloxane, a SiH group-containing compound (addition reaction type crosslinking agent) and a curing catalyst. Further, a reaction inhibitor may be contained.

  The vinyl group-containing organopolysiloxane has a repeating structure represented by the following general formula (I), and has a vinyl group at a main chain terminal or in a hydrocarbon group bonded to a silicon atom. Among them, those having a vinyl group at the terminal of the main chain are preferred. Two or more of these may be contained.

— (SiR ¹ R ² —O—) _n — (I)
In the formula, n represents an integer of 2 or more, and R ¹ and R ² represent a saturated or unsaturated hydrocarbon group having 1 to 50 carbon atoms which may be the same or different. The hydrocarbon group may be linear, branched or cyclic, and may contain an aromatic ring. Further, a plurality of R ¹ may be the same or different, and a plurality of R ² may be the same or different. However, it has at least one vinyl group in either or both of the repeating structure represented by the general formula (I) and the terminal group of the structure.

  Examples of the SiH group-containing compound include an organohydrogenpolysiloxane and an organic polymer having a diorganohydrogensilyl group, and preferably an organohydrogenpolysiloxane. Two or more of these may be contained.

  The organohydrogenpolysiloxane can have a linear, cyclic, branched, or network molecular structure. For example, polymethyl hydrogen siloxane having both molecular chains terminated with trimethylsiloxy groups, a dimethylsiloxane / methyl hydrogen siloxane copolymer having both molecular chains terminated with trimethylsiloxy groups, and dimethylhydrogen having both molecular chains terminated with dimethylhydrogen Examples thereof include dimethylpolysiloxane blocked with a gensiloxy group.

  From the viewpoint of the curability of the ink repellent layer, the content of the SiH group-containing compound is preferably 0.5% by mass or more, more preferably 1% by mass or more when the mass of the ink repellent layer is 100% by mass. Further, it is preferably at most 20% by mass, more preferably at most 15% by mass.

  Examples of the reaction inhibitor that the addition reaction type silicone rubber may contain include a nitrogen-containing compound, a phosphorus compound, and an unsaturated alcohol, and an acetylene group-containing alcohol is preferably used. Two or more of these may be contained.

  In the addition reaction type silicone rubber, the curing catalyst can be selected from known ones. Platinum compounds are preferable, and specific examples thereof include simple platinum, platinum chloride, chloroplatinic acid, olefin-coordinated platinum, an alcohol-modified complex of platinum, and a methylvinylpolysiloxane complex of platinum. Two or more of these may be contained.

  In addition to these components, addition-reaction-type silicone rubbers include known organopolysiloxanes containing hydroxyl groups, silanes containing hydrolyzable functional groups or siloxanes containing these functional groups, and silica for improving rubber strength. And a known silane coupling agent for the purpose of improving adhesiveness. As the silane coupling agent, alkoxysilanes, acetoxysilanes, ketoximinosilanes and the like are preferable, and those in which a vinyl group or an allyl group is directly bonded to a silicon atom are preferable.

  The condensation reaction type silicone rubber preferably uses at least a hydroxyl group-containing organopolysiloxane, a crosslinking agent and a curing catalyst as raw materials.

  The hydroxyl group-containing organopolysiloxane has a repeating structure represented by the following general formula (I '), and has a hydroxyl group at a main chain terminal or in a hydrocarbon group bonded to a silicon atom. Among them, those having a hydroxyl group at the terminal of the main chain are preferred. Two or more of these may be contained.

— (SiR ^{1 ′} R ^{2 ′} —O—) _n − (I ′)
In the formula, n represents an integer of 2 or more, and R ^{1 ′} and R ^{2 ′} represent a hydrocarbon group having or not having a hydroxyl group having 1 to 50 carbon atoms which may be the same or different. The hydrocarbon group may be linear, branched or cyclic, and may contain an aromatic ring. A plurality of R ^1's may be the same or different from each other, and a plurality of R ^2's may be the same or different from each other. However, it has at least one hydroxyl group in either or both of the repeating structure represented by the general formula (I ′) and the terminal group of the structure.

Examples of the cross-linking agent contained in the condensation reaction type silicone rubber include a deacetic acid type, a deoxime type, a dealcohol type, a deacetone type, a deamide type, a dehydroxylamine type represented by the following general formula (II). Can be mentioned.
^{_{(R 3) 4-m SiX}} m (II)
In the formula, m represents an integer of 2 to 4, R ³ may be the same or different, and represents a substituted or unsubstituted alkyl group, alkenyl group, aryl group having 1 or more carbon atoms, or a combination thereof. Show. X may be the same or different and represents a hydrolyzable group. Examples of the hydrolyzable group include an acyloxy group such as an acetoxy group, a ketoxime group such as a methylethylketoxime group, and an alkoxy group such as a methoxy group, an ethoxy group, a propoxy group, and a butoxy group. In the above formula, the number m of the hydrolyzable groups is preferably 3 or 4.

  The addition amount of the crosslinking agent in the condensation reaction type silicone rubber is preferably 0.5% by mass or more, more preferably 1% by mass or more in the silicone rubber from the viewpoint of the stability of the silicone rubber and its solution. Further, from the viewpoint of the strength of the ink repellent layer and the scratch resistance of the lithographic printing plate, the content in the silicone rubber is preferably 20% by mass or less, more preferably 15% by mass or less.

  Examples of the curing catalyst contained in the condensation reaction type silicone rubber include dibutyltin diacetate, dibutyltin dioctate, dibutyltin dilaurate, zinc octylate, and iron octylate. Two or more of these may be contained.

  In the lithographic printing plate precursor according to the invention, the ink repellent layer may contain an ink repellent liquid for the purpose of improving the sensitivity upon laser irradiation or improving the ink repulsion. Here, the ink-repellent liquid is a liquid having a property that the action of repelling ink in the ink-repellent layer is increased as compared with the case where the ink-repellent liquid is not contained. It is preferable to use one having a boiling point at atmospheric pressure of 150 ° C. or higher. By containing the ink repellent liquid, when the plate surface is pressurized during printing, the ink repellent liquid is exposed on the surface of the ink repellent layer, and the ink repellency is improved by helping the ink to be removed. Further, since the crosslinked structure of the ink repellent layer is weakened at the time of preparation of the original plate, the ink repellent layer is easily removed at the time of development, and the sensitivity at the time of laser irradiation is improved. When the boiling point is 150 ° C. or higher, the lithographic printing plate precursor is less likely to volatilize during production, and the effect of the ink repellency obtained by including the ink repellent liquid is less likely to be lost.

  The content of the ink repellent liquid contained in the ink repellent layer is preferably 4% by mass or more when the mass of the ink repellent layer is 100% by mass. By setting the content of the ink repellent liquid to 4% by mass or more, the sensitivity at the time of laser irradiation and the ink repellency can be further improved. The content of the ink repellent liquid is more preferably 5% by mass or more when the mass of the ink repellent layer is 100% by mass. On the other hand, the content of the ink repellent liquid is preferably 30% by mass or less, more preferably 20% by mass or less, when the mass of the ink repellent layer is 100% by mass. By setting it in such a range, the silicone peeling resistance can be maintained in a high state.

  The ink repellent liquid is preferably a silicone compound, and more preferably a silicone oil. Such silicone compounds include, for example, dimethyl silicone oils such as dimethylpolydimethylsiloxane terminated, cyclic polydimethylsiloxane, dimethyl-polydimethyl-polymethylphenylsiloxane-terminated copolymer, alkyl-modified silicone oil, and fluorine-modified silicone oil And modified silicone oils in which various organic groups are introduced into some of the methyl groups in the molecule, such as polyether-modified silicone oils.

  The molecular weight of these silicone oils is not particularly limited, but preferably, when measured by gel permeation chromatography (GPC) using polystyrene as a standard, the weight average molecular weight Mw is preferably 1,000 to 100,000. .

  The average thickness of the ink repellent layer is preferably 0.5 to 20 μm. By setting the average thickness of the ink repelling layer to 0.5 μm or more, the ink repellency, scratch resistance, and printing durability of the printing plate become sufficient, and by setting the average thickness to 20 μm or less, there is no disadvantage from an economic viewpoint, and image reproduction Of ink and ink mileage are unlikely to occur. Here, the average film thickness of the ink repellent layer can be determined by cross-sectional observation using a transmission electron microscope. More specifically, the film thickness can be measured by preparing a sample from the lithographic printing plate precursor by an ultra-thin section method and observing the sample directly under the conditions of an acceleration voltage of 100 kV and a magnification of 2000 times. The average film thickness can be determined by measuring the film thickness at 10 locations randomly selected from the ink repellent layer and calculating the number average value.

  Next, a method for producing a lithographic printing plate from the lithographic printing plate precursor according to the invention will be described. The method for producing a lithographic printing plate comprises: (A) a step of irradiating the lithographic printing plate precursor with actinic rays to form a latent image on the lithographic printing plate precursor (exposure step); (B) a step of applying physical friction to the exposed lithographic printing plate precursor to remove the ink repellent layer (development step). When a colored layer is used, the developing step may be a step of removing the colored layer together with the ink repellent layer, or a step of separately removing the colored layer may be used. The obtained lithographic printing plate is obtained by removing the ink repellent layer in the portion corresponding to the image area from the surface of the lithographic printing plate precursor, and preferably removing the colored layer when a colored layer is provided. Will be done.

  First, the step (exposure step) of forming the latent image shown in FIG. Examples of the light source used in the exposure step include a light source having an emission wavelength range of 300 nm to 1500 nm. Among these, a semiconductor laser or a YAG laser having an emission wavelength region near the near-infrared region has a high light-absorbing effect on an infrared-absorbing compound used in a heat-sensitive layer and has high versatility as a light source. Is preferably used. Specifically, a laser beam having a wavelength of 780 nm, 808 nm, 830 nm, or 1064 nm is preferably used in the exposure step from the viewpoint of heat conversion efficiency. The lithographic printing plate precursor may be colored by exposure, but the meaning of the formation of the latent image in the present invention is that by the action of exposure, a portion to be removed and a portion not removed by the next development step are obtained. That means.

  Next, the step (development step) of removing the ink repellent layer shown in (B) will be described. In the developing step, the lithographic printing plate precursor after exposure is given physical friction to remove the ink repellent layer in the exposed area. As a method of giving physical friction, a method of rubbing with a rotating brush with water or an aqueous solution interposed therebetween without using a pretreatment liquid is preferable. Other methods for imparting physical friction include (i) a method of wiping the plate surface with a nonwoven fabric, absorbent cotton, cloth, sponge, or the like impregnated with water or an aqueous solution or another liquid, or (ii) a plate surface with water, an aqueous solution, or another liquid. After pre-treatment, a method such as rubbing with a rotating brush while showering a liquid such as water, and (iii) a method of injecting high-pressure water, hot water, or steam onto the plate surface. When a colored layer is used, the colored layer can be removed in this step together with the ink repellent layer.

  Prior to the development, if necessary, a pretreatment in which the lithographic printing plate precursor is immersed in a pretreatment liquid for a certain period of time may be performed. Examples of the pretreatment liquid include water, a solvent obtained by adding a polar solvent such as alcohol, ketone, ester and carboxylic acid to water, and a solvent containing at least one kind of aliphatic hydrocarbons and aromatic hydrocarbons. To which a polar solvent is added, or a polar solvent is used. As the pretreatment liquid, for example, a pretreatment liquid containing polyethylene ether diol and a diamine compound having two or more primary amino groups as described in Japanese Patent No. 4839987 can be used. Specific examples of the pretreatment liquid include PP-1, PP-3, PP-F, PP-FII, PTS-1, CP-1, CP-Y, NP-1, and DP-1 (all of which are manufactured by Toray Industries, Inc. ))).

  As the liquid to be interposed in the developing step, for example, water, an aqueous solution in which 50% by mass or more of the whole solution is water, alcohol, or a paraffinic hydrocarbon can be used. Also, a mixture of propylene glycol, dipropylene glycol, triethylene glycol, polypropylene glycol, a propylene glycol derivative such as an alkylene oxide adduct to polypropylene glycol, and water can be used. Specific examples of such a liquid include HP-7N and WH-3 (both manufactured by Toray Industries, Inc.). Known surfactants can also be added to these. As the surfactant, those having a pH of 5 to 8 when converted into an aqueous solution are preferable from the viewpoints of safety, cost at the time of disposal, and the like. The content of the surfactant is preferably 10% by mass or less as the concentration of the solution. Liquids interposed in these developing steps have high safety and are preferred in terms of economical efficiency such as disposal cost.

  Part or all of the developing step can be automatically performed by an automatic developing machine. As the automatic developing machine, for example, the following devices can be used. Apparatus having only a developing section, an apparatus having a pre-processing section and a developing section in this order, an apparatus having a pre-processing section, a developing section, and a post-processing section in this order, a pre-processing section, a developing section, a post-processing section, and washing with water. A device whose units are provided in this order. Specific examples of such an automatic developing machine include TWL-650 series, TWL-860 series, TWL-1160 series (both manufactured by Toray Industries, Inc.), and JP-A-5-6000. An automatic developing machine in which a pedestal is dented into a curved surface in order to suppress the generation of scratches on the back surface of the plate is exemplified. These may be used in combination.

  Further, after the development step, a step of removing the colored layer can be separately performed, but the method is not particularly limited as long as the colored layer can be removed. Examples thereof include changing the physical friction process and conditions described in the above-described development process and changing the intervening liquid according to the material used for the colored layer.

  Next, an example of a method for producing a printed matter from the planographic printing plate of the invention will be described. The lithographic printing plate of the present invention can be used for both printing with water and printing without water, but from the viewpoint of the quality of printed matter, printing without water using fountain solution is more preferable. The layer derived from the heat-sensitive layer from which the ink repellent layer and the colored layer have been removed becomes an ink receiving layer, which becomes an image area. The ink repellent layer becomes a non-image area. It can be said that the ink receiving layer and the ink repellent layer have only a step on the order of microns and are substantially flush with each other. Then, the ink is applied only to the image portion by utilizing the difference in ink adhesion, and then the ink is transferred to the printing medium and printed. The printing medium refers to all printing media such as thin paper, cardboard, film, and label, and is not particularly limited. The transfer of the ink may be performed directly from the lithographic printing plate to the printing medium, or may be performed via a blanket.

  Hereinafter, the present invention will be described more specifically with reference to Examples, but the present invention should not be construed as being limited to these Examples.

(1) Evaluation of whether or not it has the property of thermally decomposing without undergoing melting Under a nitrogen atmosphere of 80 mL / min using a differential thermogravimetric simultaneous measurement device “TG / DTA6200” (manufactured by Seiko Instruments Inc.). The temperature was raised from 30 ° C. to 500 ° C. at a rate of 10 ° C./min, and TG / DTA was measured. From the obtained TG / DTA curve, the onset temperature of the thermal decomposition (if it is difficult to determine the starting point, the temperature shows a 5% weight loss), and the melting peak (the endothermic peak without weight loss) Read the peak temperature. Compounds in which no melting peak was observed were determined to have the property of thermally decomposing without undergoing melting. On the other hand, it was determined that a compound in which the peak temperature was observed at a temperature lower than the above-mentioned thermal decomposition start temperature in a temperature range of 100 ° C. or higher did not have the property of thermally decomposing without undergoing melting.

(2) 10 mJ Evaluation lithographic printing plate precursor of the reflected light density differences using the CTP exposure machine "PlateRite 8800E" (Dainippon Screen Mfg. Co., Ltd.), the irradiation energy from 100 mJ / cm ² to 250 mJ / cm ² / Cm ² , and exposure was performed at a total of 16 levels. A solid image of 20 mm in length and 20 mm in width was projected and exposed to a central region of a lithographic printing plate precursor having 550 mm in length and 650 mm in width at a total of 16 places with each laser output. Subsequently, the exposed original plate was passed through an automatic developing machine “TWL-1160F” (manufactured by Toray Industries, Ltd.) at a speed of 60 cm / min with tap water interposed therebetween without performing pretreatment, thereby producing a lithographic printing plate. Observing the solid image of the obtained lithographic printing plate, the solid image obtained with the lowest laser output among the solid image reproduced is measured with a reflection densitometer "spectro eye" (manufactured by X-rite). The measured reflected light density was defined as the reflected light density of the exposed portion. Next, the unexposed portion was measured with a reflection densitometer “spectro eye” (manufactured by X-rite), and the obtained value was defined as the reflected light density of the unexposed portion. The measurement of the reflected light density is performed with cyan, yellow, or magenta filters applied, respectively, and the absolute value of the difference between the reflection density of the unexposed part and the reflection density of the exposed part with each filter applied is measured. ΔD _C , ΔD _Y , and ΔD _M were used, and the one with the largest value was adopted. If the difference in reflected light density is 0.3 or more, it can be used without any practical problem. Also, the larger the numerical value, the better the plate inspection. It should be noted that whether or not the solid image was reproduced was confirmed by observing the solid image with an optical microscope “ECLIPSE L200N” (manufactured by Nikon Corporation) and confirming that the ink repellent layer in the solid image portion was completely removed. Was reproduced. The detailed conditions for measuring the reflected light density are as follows.

  After setting the measurement conditions of a reflection densitometer “spectro eye” (manufactured by X-rite) to the built-in filter: No, white base: Auto, light source: D50, observation field of view: 2 °, density standard ISOT, and then to density measurement mode , Cyan was selected as a filter, and the reflection density of the exposed part and the unexposed part was measured. Next, after changing the filter to yellow and magenta, the measurement was performed in the same manner.

(3) by using the evaluation of the laser power required developing a lithographic printing plate precursor for CTP exposure device "PlateRite 8800E" (Dainippon Screen Mfg. Co., Ltd.), 250 mJ irradiation energy from 100mJ / cm ² / cm ² Exposure was performed at a total of 16 levels, increasing by 10 mJ / cm ² until the exposure was completed. A solid image of 20 mm in length and 20 mm in width was projected and exposed to a central region of a lithographic printing plate precursor having 550 mm in length and 650 mm in width at a total of 16 places with each laser output. Subsequently, the exposed original plate was passed through an automatic developing machine “TWL-1160F” (manufactured by Toray Industries, Ltd.) at a speed of 60 cm / min with tap water interposed therebetween without performing pretreatment, thereby producing a lithographic printing plate. A solid image of the obtained lithographic printing plate was observed, and a laser output value at a laser output having the lowest laser output among solid image reproductions was defined as a laser output required for development. If the value of the laser output is 240 mJ / cm ² or less, it can be used without any practical problem. Also, the lower the numerical value, the higher the sensitivity.

(4) Evaluation of anti-silicone peeling A lithographic printing plate precursor was prepared in a size of 500 mm long × 100 mm wide and 10 μL each of 3-methoxy-3-methyl-1-butanol (25 ° C.) was placed on the ink repelling layer at 200 μL. After 5 minutes, 10 minutes, 15 minutes, 20 minutes, 25 minutes, 30 minutes, 35 minutes, 40 minutes, 45 minutes, and 50 minutes, they were rubbed and wiped five times with a cotton pad. The surface of the lithographic printing plate after wiping was visually observed, and the longest time of the silicone rubber at the place where 3-methoxy-3-methyl-1-butanol was dropped without peeling was examined. 1 point, 2 points, 3 points, 4 points, 5 points, 6 points, 7 points, 8 points, 9 points, and 10 points, respectively. In other words, three points are left if they were left at 15 minutes but were peeled off at 20 minutes. The higher the score, the better the silicone peeling resistance. If the score is 3 or more, it can be used without practical problems.

[Example 1]
A lithographic printing plate precursor was prepared by the following method.

  The underlayer composition described below was applied on an aluminum substrate (manufactured by Norsk Hydro) having a thickness of 0.27 mm, and dried at 210 ° C. for 86 seconds in a safety oven “SPH-200” (manufactured by Espec Corporation). An underlayer of 0.4 μm was provided. The underlayer composition was obtained by stirring and mixing the following components at room temperature.

<Underlayer composition>
(A) Polymer having active hydrogen: epoxy resin: “Epicoat” (registered trademark) 1010 (manufactured by Japan Epoxy Resin Co., Ltd.): 30.4 parts by mass (b) Polymer having active hydrogen: polyurethane: “Samprene” ( (Registered trademark) LQ-T1331D (manufactured by Sanyo Chemical Industries, Ltd., solid content concentration: 20% by mass): 57.3 parts by mass (c) Aluminum chelate: aluminum chelate ALCH-TR (manufactured by Kawaken Fine Chemical Co., Ltd.): 6.2 parts by mass (d) Leveling agent: "DISPARON" (registered trademark) LC951 (manufactured by Kusumoto Kasei Co., Ltd., solid content: 10% by mass): 0.1 part by mass (e) Titanium oxide: "Taipek" ( N, N-dimethylformamide dispersion (registered trademark) CR-50 (manufactured by Ishihara Sangyo Co., Ltd.) (titanium oxide: 50% by mass): 6.0 parts by mass (f) N, N-dimethylforme Amide: 450 parts by mass (g) Methyl ethyl ketone: 150 parts by mass The compounding amount (parts by mass) of each component of the underlayer composition is represented by 100 parts by mass as the total mass of components (a) to (e). .

  Next, the following heat-sensitive layer composition-1 was applied on the underlayer, and dried by heating at 140 ° C. for 80 seconds to provide a heat-sensitive layer having a thickness of 1.2 μm. In addition, the thermosensitive layer composition-1 was obtained by stirring and mixing the following components at room temperature.

<Thermosensitive layer composition-1>
(A) Phenol formaldehyde novolak resin: "Sumilite Resin" (registered trademark) PR53195 (manufactured by Sumitomo Bakelite Co., Ltd.): 64.2 parts by mass (b) Polyurethane: "Samprene" (registered trademark) LQ-T1333 (Sanyo Chemical Industries, Ltd.) 10.7 parts by mass (c) Infrared absorbing compound: "YKR2016" (manufactured by Yamamoto Kasei Co., Ltd.): 12.0 parts by mass (d) Titanium chelate: "Nasem" (registered trademark) titanium ( (Manufactured by Nippon Chemical Industry Co., Ltd.): 13.1 parts by mass (e) tetrahydrofuran: 614 parts by mass (f) t-butanol: 207 parts by mass (g) N, N-dimethylformamide: 18 parts by mass (h) ethanol: 61 parts by mass The compounding amount (parts by mass) of each component of the heat-sensitive layer composition-1 is shown with the total mass of the components (a) to (d) being 100 parts by mass.

  Next, the following colored layer composition-1 was applied on the heat-sensitive layer, and dried by heating at 140 ° C. for 80 seconds to provide a colored layer having a thickness of 0.4 μm. In addition, the colored layer composition-1 was obtained by stirring and mixing the following components at room temperature.

<Colored layer composition-1>
(A) Binder polymer: polymethyl methacrylate (manufactured by Wako Pure Chemical Industries, Ltd., weight average molecular weight: 6000): 97.0 parts by mass (b) Dye compound: methyl orange (a property that thermally decomposes without melting) : Nothing, λ _max = 400 to 600 nm) (manufactured by Wako Pure Chemical Industries, Ltd.): 3.0 parts by mass (c) Tetrahydrofuran: 900 parts by mass In addition, the compounding amount of each component of the colored layer composition-1 ( Parts by mass) are shown assuming that the total mass of the components (a) and (b) is 100 parts by mass.

  Next, the following ink repellent layer composition prepared immediately before coating is applied onto the color layer, and heated at 140 ° C. for 70 seconds to provide an ink repellent layer (silicone rubber layer) having an average film thickness of 3.0 μm. Lithographic printing plate precursor-1 was obtained. The ink repellent layer composition was obtained by stirring and mixing the following components at room temperature.

<Ink repellent layer composition-1 (abbreviated as "composition-1" in the table. Hereinafter, similarly abbreviated)>
(A) α, ω-divinylpolydimethylsiloxane: DMS-V35 (weight average molecular weight 49,500, manufactured by Gelest Inc.): 86.95 parts by mass (b) Methyl hydrogen siloxane RD-1 (Dow Corning Toray) (C) vinyltris (methylethylketooxyimino) silane: 2.64 parts by mass (d) Platinum catalyst SRX212 (manufactured by Dow Corning Toray Co., Ltd .; 6.0% by mass of platinum catalyst) ): 6.17 parts by mass (e) "Isopar" E (manufactured by Esso Chemical Co., Ltd.): 900 parts by mass The compounding amount (parts by mass) of each component of the ink repellent layer composition-1 is represented by the component (a) 〜 (D) is shown as 100 parts by mass.

When the obtained lithographic printing plate precursor was evaluated by the above-described method, the difference in reflected light density was 0.30, the laser output required for development was 180 mJ / cm ² , and the silicone peeling resistance was 9 points. Good results were obtained. Was.

[Example 2]
Lithographic printing plate precursor-2 was obtained in the same manner as in Example 1, except that the colored layer composition-1 was changed to the following colored layer composition-2.

<Colored layer composition-2>
(A) Binder polymer: polymethyl methacrylate (Wako Pure Chemical Industries, Ltd., weight average molecular weight: 6000): 95.0 parts by mass (b) Dye compound: methyl orange (decomposes thermally without melting) Properties: None, λ _max = 400-600 nm) (manufactured by Wako Pure Chemical Industries, Ltd.): 5.0 parts by mass (c) Tetrahydrofuran: 900 parts by mass In addition, the compounding amount of each component of the colored layer composition-2 (Parts by mass) is shown with the total mass of the components (a) and (b) being 100 parts by mass.

When the obtained lithographic printing plate precursor-2 was evaluated by the above method, the difference in reflected light density was 0.50, the laser output required for development was 180 mJ / cm ² , and the silicone peeling resistance was 8 points. Obtained.

[Example 3]
Lithographic printing plate precursor-3 was obtained in the same manner as in Example 1, except that the colored layer composition-1 was changed to the following colored layer composition-3.

<Colored layer composition-3>
(A) Binder polymer: polymethyl methacrylate (Wako Pure Chemical Industries, Ltd., weight average molecular weight: 6000): 90.0 parts by mass (b) Dye compound: methyl orange (thermally decomposes without melting) Properties: None, λ _max = 400-600 nm) (manufactured by Wako Pure Chemical Industries, Ltd.): 10.0 parts by mass (c) Tetrahydrofuran: 900 parts by mass In addition, the compounding amount of each component of the above-mentioned colored layer composition-3 (Parts by mass) is shown with the total mass of the components (a) and (b) being 100 parts by mass.

When the obtained lithographic printing plate precursor-3 was evaluated by the above method, the difference in reflected light density was 0.75, the laser output required for development was 180 mJ / cm ² , and the silicone peeling resistance was 8 points. Obtained.

[Example 4]
Lithographic printing plate precursor-4 was obtained in the same manner as in Example 1, except that the colored layer composition-1 was changed to the following colored layer composition-4.

<Colored layer composition-4>
(A) Binder polymer: polymethyl methacrylate (Wako Pure Chemical Industries, Ltd., weight average molecular weight: 6000): 85.0 parts by mass (b) Dye compound: methyl orange (thermally decomposes without melting) Properties: None, λ _max = 400 to 600 nm (manufactured by Wako Pure Chemical Industries, Ltd.): 15.0 parts by mass (c) Tetrahydrofuran: 900 parts by mass In addition, the compounding amount of each component of the colored layer composition-4 (Parts by mass) is shown with the total mass of the components (a) and (b) being 100 parts by mass.

When the obtained lithographic printing plate precursor-4 was evaluated by the above method, the difference in reflected light density was 0.95, the laser output required for development was 180 mJ / cm ² , and the silicone peeling resistance was 7 points. Obtained.

[Example 5]
A lithographic printing plate precursor-5 was obtained in the same manner as in Example 1, except that the colored layer composition-1 was changed to the following colored layer composition-5.

<Colored layer composition-5>
(A) Binder polymer: polymethyl methacrylate (Wako Pure Chemical Industries, Ltd., weight average molecular weight: 6000): 70.0 parts by mass (b) Dye compound: methyl orange (decomposes thermally without melting) Properties: None, λ _max = 400 to 600 nm) (manufactured by Wako Pure Chemical Industries, Ltd.): 30.0 parts by mass (c) Tetrahydrofuran: 900 parts by mass In addition, the compounding amount of each component of the above-mentioned colored layer composition-5 (Parts by mass) is shown with the total mass of the components (a) and (b) being 100 parts by mass.

When the obtained lithographic printing plate precursor-5 was evaluated by the above method, the reflected light density difference was 1.15, the laser output required for development was 180 mJ / cm ² , and the silicone peeling resistance was 7 points. Obtained.

[Example 6]
A lithographic printing plate precursor-6 was obtained in the same manner as in Example 1, except that the colored layer composition-1 was changed to the following colored layer composition-6.

<Colored layer composition-6>
(A) Binder polymer: polymethyl methacrylate (Wako Pure Chemical Industries, Ltd., weight average molecular weight: 6000): 60.0 parts by mass (b) Dye compound: methyl orange (decomposes thermally without melting) Properties: None, λ _max = 400 to 600 nm) (manufactured by Wako Pure Chemical Industries, Ltd.): 40.0 parts by mass (c) Tetrahydrofuran: 900 parts by mass The amount of each component of the above-mentioned colored layer composition-6 (Parts by mass) is shown with the total mass of the components (a) and (b) being 100 parts by mass.

When the obtained lithographic printing plate precursor-6 was evaluated by the above method, the reflected light density difference was 1.20, the laser output required for development was 180 mJ / cm ² , and the silicone peeling resistance was 5 points. Obtained.

[Example 7]
A lithographic printing plate precursor-7 was obtained in the same manner as in Example 1, except that the colored layer composition-1 was changed to the following colored layer composition-7.

<Colored layer composition-7>
(A) Binder polymer: polymethyl methacrylate (Wako Pure Chemical Industries, Ltd., weight average molecular weight: 6000): 50.0 parts by mass (b) Dye compound: methyl orange (decomposes thermally without melting) Properties: None, λ _max = 400-600 nm) (manufactured by Wako Pure Chemical Industries, Ltd.): 50.0 parts by mass (c) Tetrahydrofuran: 900 parts by mass In addition, the compounding amount of each component of the above-mentioned colored layer composition-7 (Parts by mass) is shown with the total mass of the components (a) and (b) being 100 parts by mass.

When the obtained planographic printing plate precursor-7 was evaluated by the above method, the reflected light density difference was 1.25, the laser output required for development was 180 mJ / cm ² , and the silicone peeling resistance was 4 points. Obtained.

Example 8
A lithographic printing plate precursor-8 was obtained in the same manner as in Example 1, except that the colored layer composition-1 was changed to the following colored layer composition-8.

<Colored layer composition-8>
(A) Binder polymer: polymethyl methacrylate (Wako Pure Chemical Industries, Ltd., weight average molecular weight: 6000): 45.0 parts by mass (b) Dye compound: methyl orange (thermally decomposes without melting) Properties: None, λ _max = 400-600 nm) (manufactured by Wako Pure Chemical Industries, Ltd.): 55.0 parts by mass (c) Tetrahydrofuran: 900 parts by mass In addition, the compounding amount of each component of the above-mentioned colored layer composition-8 (Parts by mass) is shown with the total mass of the components (a) and (b) being 100 parts by mass.

When the obtained lithographic printing plate precursor-8 was evaluated by the above method, the difference in optical reflected light density was 1.25, the laser output required for development was 180 mJ / cm ² , and the silicone peeling resistance was 3 points. was gotten.

[Example 9]
A lithographic printing plate was prepared in the same manner as in Example 1 except that the colored layer composition-1 was changed to the following colored layer composition-9, and the thickness of the colored layer was further changed from 0.4 μm to 0.5 μm. Master-9 was obtained.

<Colored layer composition-9>
(A) Binder polymer: polymethyl methacrylate (Wako Pure Chemical Industries, Ltd., weight average molecular weight: 6000): 75.0 parts by mass (b) Dye compound: methyl orange (decomposes thermally without melting) Properties: None, λ _max = 400-600 nm) (manufactured by Wako Pure Chemical Industries, Ltd.): 25.0 parts by mass (c) Tetrahydrofuran: 900 parts by mass Ingredients of each component of the colored layer composition-9 (Parts by mass) is shown with the total mass of the components (a) and (b) being 100 parts by mass.

When the obtained lithographic printing plate precursor-9 was evaluated by the above method, the reflected light density difference was 1.08, the laser output required for development was 180 mJ / cm ² , and the silicone peeling resistance was 7 points. Obtained.

[Example 10]
A lithographic printing plate precursor-10 was obtained in the same manner as in Example 9, except that the thickness of the colored layer was changed from 0.5 μm to 0.8 μm.

When the obtained lithographic printing plate precursor-10 was evaluated by the above method, the reflected light density difference was 1.15, the laser output required for development was 180 mJ / cm ² , and the silicone peeling resistance was 7 points. Obtained.

[Example 11]
Lithographic printing plate precursor-11 was obtained in the same manner as in Example 9 except that the thickness of the colored layer was changed from 0.5 μm to 1.0 μm.

When the obtained lithographic printing plate precursor-11 was evaluated by the above method, the reflected light density difference was 1.20, the laser output required for development was 190 mJ / cm ² , and the silicone peeling resistance was 8 points. Obtained.

[Example 12]
A lithographic printing plate precursor-12 was obtained in the same manner as in Example 9, except that the thickness of the colored layer was changed from 0.5 μm to 2.0 μm.

When the obtained lithographic printing plate precursor-12 was evaluated by the above method, the difference in reflected light density was 1.40, the laser output required for development was 200 mJ / cm ² , and the silicone peeling resistance was 8 points. Obtained.

Example 13
Lithographic printing plate precursor-13 was obtained in the same manner as in Example 9, except that the thickness of the colored layer was changed from 0.5 μm to 2.5 μm.

When the obtained lithographic printing plate precursor-13 was evaluated by the above method, the difference in reflected light density was 1.47, the laser output required for development was 220 mJ / cm ² , and the silicone peeling resistance was 9 points. Obtained.

[Example 14]
A lithographic printing plate precursor-14 was obtained in the same manner as in Example 9, except that the thickness of the colored layer was changed from 0.5 μm to 3.0 μm.

When the obtained lithographic printing plate precursor-14 was evaluated by the above method, the reflected light density difference was 1.50, the laser output required for development was 230 mJ / cm ² , and the silicone peeling resistance was 10 points. Obtained.

[Example 15]
A lithographic printing plate precursor-15 was obtained in the same manner as in Example 9, except that the thickness of the colored layer was changed from 0.5 μm to 3.5 μm.

When the obtained planographic printing plate precursor-15 was evaluated by the above method, the difference in reflected light density was 1.50, the laser output required for development was 240 mJ / cm ² , and the silicone peeling resistance was 10 points. Obtained.

[Example 16]
A lithographic printing plate was prepared in the same manner as in Example 1 except that the colored layer composition-1 was changed to the following colored layer composition-10, and the thickness of the colored layer was further changed from 0.4 μm to 1.5 μm. Master plate-16 was obtained.

<Colored layer composition-10>
(A) Binder polymer: meta-paracresol novolak resin: "LF-100" (manufactured by Lignite Co., Ltd.): 75.0 parts by mass (b) Dye compound: methyl orange (the property of thermally decomposing without melting: none) , Λ _max = 400 to 600 nm) (manufactured by Wako Pure Chemical Industries, Ltd.): 25.0 parts by mass (c) Tetrahydrofuran: 900 parts by mass In addition, the compounding amount (parts by mass) of each component of the above-mentioned colored layer composition-10 ) Indicates the total mass of the components (a) and (b) as 100 parts by mass.

When the obtained lithographic printing plate precursor-16 was evaluated by the above method, the difference in reflected light density was 1.30, the laser output required for development was 180 mJ / cm ² , and the silicone peeling resistance was 9 points. Obtained.

[Example 17]
A lithographic printing plate precursor-17 was obtained in the same manner as in Example 16, except that the colored layer composition-10 was changed to the following colored layer composition-11.

<Colored layer composition-11>
(A) Binder polymer: phenol formaldehyde novolak resin: “Sumilite Resin” (registered trademark) PR53195 (manufactured by Sumitomo Bakelite Co., Ltd.): 60.0 parts by mass (b) Dye compound: methyl orange (heat without melting) Decomposition property: None, λ _max = 400 to 600 nm (manufactured by Wako Pure Chemical Industries, Ltd.): 25.0 parts by mass (c) Crosslinking agent: aluminum chelate: ALCH (manufactured by Wako Pure Chemical Industries, Ltd.): 15.0 parts by mass (d) tetrahydrofuran: 900 parts by mass In addition, the compounding amount (parts by mass) of each component of the colored layer composition-11 is based on 100 parts by mass of the total mass of the components (a) to (c). Indicated.

When the obtained lithographic printing plate precursor-17 was evaluated by the above method, the reflected light density difference was 1.30, the laser output required for development was 200 mJ / cm ² , and the silicone peeling resistance was 10 points. Obtained.

[Example 18]
A lithographic printing plate precursor-18 was obtained in the same manner as in Example 16, except that the colored layer composition-10 was changed to the following colored layer composition-12.

<Colored layer composition-12>
(A) Binder polymer: phenol formaldehyde novolak resin: “Sumilite Resin” (registered trademark) PR53195 (manufactured by Sumitomo Bakelite Co., Ltd.): 60.0 parts by mass (b) Dye compound: methyl orange (heat without melting) Decomposition property: None, λ _max = 400 to 600 nm (manufactured by Wako Pure Chemical Industries, Ltd.): 25.0 parts by mass (c) Crosslinking agent: titanium chelate: “Nasem” (registered trademark) titanium (Nippon Chemical Industry) (Manufactured by K.K.): 15.0 parts by mass (d) Tetrahydrofuran: 900 parts by mass The compounding amount (parts by mass) of each component of the colored layer composition-12 is the sum of components (a) to (c). The mass is shown as 100 parts by mass.

When the obtained lithographic printing plate precursor-18 was evaluated by the above method, the reflected light density difference was 1.30, the laser output required for development was 200 mJ / cm ² , and the silicone peeling resistance was 10 points. Obtained.

[Example 19]
A lithographic printing plate precursor-19 was obtained in the same manner as in Example 16 except that the colored layer composition-10 was changed to the following colored layer composition-13.

<Colored layer composition-13>
(A) Binder polymer: phenol formaldehyde novolak resin: “Sumilite Resin” (registered trademark) PR53195 (manufactured by Sumitomo Bakelite Co., Ltd.): 54.4 parts by mass (b) Dye compound: methyl orange (heat without melting) Decomposition property: None, λ _max = 400 to 600 nm (manufactured by Wako Pure Chemical Industries, Ltd.): 25.0 parts by mass (c) Crosslinking agent: titanium chelate: “Nasem” (registered trademark) titanium (Nippon Chemical Industry) (Manufactured by Wako Pure Chemical Industries, Ltd.): 13.6 parts by mass (d) Non-dye compound that decomposes thermally without undergoing melting: L (+)-ascorbic acid (λ _max = 150 to 200 nm) ): 7.0 parts by mass (d) Tetrahydrofuran: 820 parts by mass (e) Methanol: 80 parts by mass The compounding amount (parts by mass) of each component of the colored layer composition-13 is represented by component (a) The total mass of (d) shown as 100 weight parts.

When the obtained lithographic printing plate precursor-19 was evaluated by the above method, the reflected light density difference was 1.30, the laser output required for development was 160 mJ / cm ² , and the silicone peeling resistance was 10 points. The result was obtained.

[Example 20]
A lithographic printing plate precursor-20 was obtained in the same manner as in Example 16, except that the colored layer composition-10 was changed to the following colored layer composition-14.

<Colored layer composition-14>
(A) Binder polymer: phenol formaldehyde novolak resin: "Sumilite Resin" (registered trademark) PR53195 (manufactured by Sumitomo Bakelite Co., Ltd.): 60.0 parts by mass (b) Dye compound: bromothymol blue (without melting) Thermal decomposition property: Yes, λ _max = 400 to 650 nm, triphenylmethane dye) (manufactured by Wako Pure Chemical Industries, Ltd.): 25.0 parts by mass (c) Crosslinking agent: titanium chelate: “Nasem” (registered trademark) ) Titanium (manufactured by Nippon Kagaku Sangyo Co., Ltd.): 15.0 parts by mass (d) Tetrahydrofuran: 900 parts by mass The amount (parts by mass) of each component of the above-mentioned colored layer composition -14 is the component (a) The total mass of (c) to (c) was shown as 100 parts by mass.

When the obtained lithographic printing plate precursor-20 was evaluated by the above method, the reflected light density difference was 1.30, the laser output required for development was 140 mJ / cm ² , and the silicone peeling resistance was 10 points. The result was obtained.

[Example 21]
A lithographic printing plate precursor-21 was obtained in the same manner as in Example 16, except that the colored layer composition-10 was changed to the following colored layer composition-15.

<Colored layer composition-15>
(A) Binder polymer: phenol formaldehyde novolak resin: "Sumilite Resin" (registered trademark) PR53195 (manufactured by Sumitomo Bakelite Co., Ltd.): 60.0 parts by mass (b) Dye compound: basic fuchsin (without melting) Thermal decomposition property: Yes, λ _max = 450-600 nm, triphenylmethane dye) (manufactured by Tokyo Chemical Industry Co., Ltd.): 25.0 parts by mass (c) Crosslinking agent: titanium chelate: “Nasem” (registered trademark) Titanium (manufactured by Nippon Chemical Industry Co., Ltd.): 15.0 parts by mass (d) Tetrahydrofuran: 900 parts by mass In addition, the compounding amount (parts by mass) of each component of the above-mentioned colored composition-15 is represented by components (a) to ( The total mass of c) was shown as 100 parts by mass.

When the obtained lithographic printing plate precursor-21 was evaluated by the above method, the difference in reflected light density was 1.30, the laser output required for development was 140 mJ / cm ² , and the silicone peeling resistance was 10 points. The result was obtained.

[Example 22]
A lithographic printing plate precursor-22 was obtained in the same manner as in Example 16 except that the colored layer composition-10 was changed to the following colored layer composition-16.

<Colored layer composition-16>
(A) Binder polymer: phenol formaldehyde novolak resin: "Sumilite Resin" (registered trademark) PR53195 (manufactured by Sumitomo Bakelite Co., Ltd.): 60.0 parts by mass (b) Dye compound: bromocresol green (without melting) Thermal decomposition property: Yes, λ _max = 400-650 nm, triphenylmethane dye) (manufactured by Sigma-Aldrich Japan): 25.0 parts by mass (c) Crosslinking agent: titanium chelate: “Nasem” (registered trademark) titanium (Japan) Chemical Industry Co., Ltd.): 15.0 parts by mass (d) Tetrahydrofuran: 900 parts by mass The compounding amounts (parts by mass) of the respective components of the above-mentioned colored composition -16 are the same as those of components (a) to (c). The total mass is shown as 100 parts by mass.

When the obtained planographic printing plate precursor-22 was evaluated by the above method, the reflected light density difference was 1.30, the laser output required for development was 140 mJ / cm ² , and the silicone peeling resistance was 10 points. The result was obtained.

[Example 23]
A lithographic printing plate precursor-23 was obtained in the same manner as in Example 16 except that the colored layer composition-10 was changed to the following colored layer composition-17.

<Colored layer composition-17>
(A) Binder polymer: phenol formaldehyde novolak resin: “Sumilite Resin” (registered trademark) PR53195 (manufactured by Sumitomo Bakelite Co., Ltd.): 60.0 parts by mass (b) Dye compound: methylene blue (thermal decomposition without melting) Properties: Yes, λ _max = 500-700 nm, thiazine dye) (manufactured by Wako Pure Chemical Industries, Ltd.): 25.0 parts by mass (c) Crosslinking agent: titanium chelate: “Nasem” (registered trademark) titanium (Japan) (Manufactured by Chemical Industry Co., Ltd.): 15.0 parts by mass (d) Tetrahydrofuran: 900 parts by mass The amount (parts by mass) of each component of the above-mentioned colored layer composition-17 is determined by the components (a) to (c). Is shown as 100 parts by mass.

When the obtained lithographic printing plate precursor-23 was evaluated by the above method, the reflected light density difference was 1.30, the laser output required for development was 140 mJ / cm ² , and the silicone peeling resistance was 10 points. The result was obtained.

[Example 24]
A lithographic printing plate precursor-24 was obtained in the same manner as in Example 16, except that the colored layer composition-10 was changed to the following colored layer composition-18.

<Colored layer composition-18>
(A) Binder polymer: phenol formaldehyde novolak resin: “Sumilite Resin” (registered trademark) PR53195 (manufactured by Sumitomo Bakelite Co., Ltd.): 60.0 parts by mass (b) Dye compound: methyl yellow (heat without melting) Decomposition property: Yes, λ _max = 400 to 600 nm, azo dye (manufactured by Tokyo Chemical Industry Co., Ltd.): 25.0 parts by mass (c) Crosslinking agent: titanium chelate: “Nasem” (registered trademark) titanium (Japan) (Manufactured by Chemical Industry Co., Ltd.): 15.0 parts by mass (d) Tetrahydrofuran: 900 parts by mass In addition, the compounding amount (parts by mass) of each component of the above-mentioned colored layer composition-18 is the components (a) to (c) Is shown as 100 parts by mass.

When the obtained lithographic printing plate precursor-24 was evaluated by the above method, the reflected light density difference was 1.30, the laser output required for development was 140 mJ / cm ² , and the silicone peeling resistance was 10 points. The result was obtained.

[Example 25]
A lithographic printing plate precursor-25 was obtained in the same manner as in Example 16 except that the colored layer composition-10 was changed to the following colored layer composition-19.

<Colored layer composition-19>
(A) Binder polymer: phenol formaldehyde novolak resin: “Sumilite Resin” (registered trademark) PR53195 (manufactured by Sumitomo Bakelite Co., Ltd.): 60.0 parts by mass (b) Dye compound: fluorescein isothiocyanate (without melting) Thermal decomposition property: Yes, λ _max = 400-600 nm, xanthene dye) (manufactured by Tokyo Chemical Industry Co., Ltd.): 25.0 parts by mass (c) Crosslinking agent: titanium chelate: “Nasem” (registered trademark) titanium ( Nippon Kagaku Sangyo Co., Ltd.): 15.0 parts by mass (d) Tetrahydrofuran: 900 parts by mass In addition, the compounding amounts (parts by mass) of each component of the above-mentioned colored layer composition-19 are components (a) to (c) ) Is shown as 100 parts by mass.

When the obtained lithographic printing plate precursor-25 was evaluated by the above method, the reflected light density difference was 1.30, the laser output required for development was 140 mJ / cm ² , and the silicone peeling resistance was 10 points. The result was obtained.

[Example 26]
A lithographic printing plate precursor-26 was obtained in the same manner as in Example 16, except that the colored layer composition-10 was changed to the following colored layer composition-20.

<Colored layer composition-20>
(A) Binder polymer: phenol formaldehyde novolak resin: “Sumilite Resin” (registered trademark) PR53195 (manufactured by Sumitomo Bakelite Co., Ltd.): 60.0 parts by mass (b) Dye compound: rhodamine 6G (heat without melting) Decomposition property: Yes, λ _max = 450-650 nm, xanthene dye) (manufactured by Tokyo Chemical Industry Co., Ltd.): 25.0 parts by mass (c) Crosslinking agent: titanium chelate: “Nasem” (registered trademark) titanium (Japan) Chemical Industry Co., Ltd.): 15.0 parts by mass (d) Tetrahydrofuran: 900 parts by mass The compounding amounts (parts by mass) of each component of the colored layer composition-20 are components (a) to (c). Is shown as 100 parts by mass.

When the obtained lithographic printing plate precursor-26 was evaluated by the above method, the reflected light density difference was 1.30, the laser output required for development was 140 mJ / cm ² , and the silicone peeling resistance was 10 points. The result was obtained.

[Example 27]
A lithographic printing plate precursor-27 was obtained in the same manner as in Example 16, except that the colored layer composition-10 was changed to the following colored layer composition-21.

<Colored layer composition-21>
(A) Binder polymer: phenol formaldehyde novolak resin: "Sumilite Resin" (registered trademark) PR53195 (manufactured by Sumitomo Bakelite Co., Ltd.): 68.0 parts by mass (b) Dye compound: bromocresol green (without melting) Thermal decomposition property: Yes, λ _max = 400-650 nm, triphenylmethane dye) (manufactured by Sigma-Aldrich Japan): 15.0 parts by mass (c) Crosslinking agent: titanium chelate: “Nasem” (registered trademark) titanium (Japan) Chemical Industry Co., Ltd.): 17.0 parts by mass (d) Tetrahydrofuran: 900 parts by mass In addition, the compounding amount (parts by mass) of each component of the colored layer composition-21 is determined by the components (a) to (c). Is shown as 100 parts by mass.

When the obtained lithographic printing plate precursor-27 was evaluated by the above method, the reflected light density difference was 1.20, the laser output required for development was 160 mJ / cm ² , and the silicone peeling resistance was 10 points. The result was obtained.

[Example 28]
A lithographic printing plate precursor-28 was obtained in the same manner as in Example 16, except that the colored layer composition-10 was changed to the following colored layer composition-22.

<Colored layer composition-22>
(A) Binder polymer: phenol formaldehyde novolak resin: "Sumilite Resin" (registered trademark) PR53195 (manufactured by Sumitomo Bakelite Co., Ltd.): 56.0 parts by mass (b) Dye compound: bromocresol green (without melting) Thermal decomposition property: yes, λ _max = 400-650 nm, triphenylmethane dye) (manufactured by Sigma-Aldrich Japan): 30.0 parts by mass (c) Crosslinking agent: titanium chelate: “Nasem” (registered trademark) titanium (Japan) (Manufactured by Chemical Industry Co., Ltd.): 14.0 parts by mass (d) Tetrahydrofuran: 900 parts by mass In addition, the compounding amount (parts by mass) of each component of the colored layer composition-22 is represented by components (a) to (c). Is shown as 100 parts by mass.

When the obtained lithographic printing plate precursor-28 was evaluated by the above method, the reflected light density difference was 1.40, the laser output required for development was 120 mJ / cm ² , and the silicone peeling resistance was 10 points. The result was obtained.

[Example 29]
A lithographic printing plate precursor-29 was obtained in the same manner as in Example 22, except that the thickness of the colored layer was changed from 1.5 μm to 1.0 μm.

When the obtained planographic printing plate precursor-29 was evaluated by the above method, the reflected light density difference was 1.20, the laser output required for development was 130 mJ / cm ² , and the silicone peeling resistance was 10 points. The result was obtained.

[Example 30]
A lithographic printing plate precursor-30 was obtained in the same manner as in Example 22, except that the thickness of the colored layer was changed from 1.5 µm to 2.0 µm.

When the obtained lithographic printing plate precursor-30 was evaluated by the above method, the reflected light density difference was 1.40, the laser output required for development was 150 mJ / cm ² , and the silicone peeling resistance was 10 points. The result was obtained.

[Example 31]
A lithographic printing plate precursor-31 was obtained in the same manner as in Example 22, except that the ink repulsion layer composition-1 was changed to the following ink repulsion layer composition-2.

<Ink repellent layer composition-2>
(A) α, ω-divinylpolydimethylsiloxane: DMS-V35 (weight average molecular weight 49,500, manufactured by GELEST Inc.): 84.09 parts by mass (b) Methyl hydrogen siloxane RD-1 (Dow Corning Toray) Co., Ltd.): 4.10 parts by mass (c) Silicone oil: KF-96-50cs (weight average molecular weight: 3,780, boiling point:> 150 ° C., manufactured by Shin-Etsu Chemical Co., Ltd.): 3.0 parts by mass (D) Vinyl tris (methylethylketooxyimino) silane: 2.64 parts by mass (e) Platinum catalyst SRX212 (manufactured by Dow Corning Toray Co., Ltd., 6.0% by mass of platinum catalyst): 6.17 parts by mass (f) "Isopar" E (manufactured by Esso Chemical Co., Ltd.): 900 parts by mass. The compounding amount (parts by mass) of each component of the ink repellent layer composition-2 is 1 part of the total mass of the components (a) to (e). 0 indicated as parts by weight.

When the obtained lithographic printing plate precursor-31 was evaluated by the above method, the reflected light density difference was 1.30, the laser output required for development was 130 mJ / cm ² , and the silicone peeling resistance was 10 points. The result was obtained.

[Example 32]
A lithographic printing plate precursor-32 was obtained in the same manner as in Example 22, except that the ink repulsion layer composition-1 was changed to the following ink repulsion layer composition-3.

<Ink repellent layer composition-3>
(A) α, ω-divinylpolydimethylsiloxane: DMS-V35 (weight average molecular weight 49,500, manufactured by GELEST Inc.): 83.14 parts by mass (b) Methyl hydrogen siloxane RD-1 (Dow Corning Toray) (Manufactured by Shin-Etsu Chemical Co., Ltd.): 4.05 parts by mass (c) Silicone oil: KF-96-50cs (weight average molecular weight: 3,780, boiling point:> 150 ° C., manufactured by Shin-Etsu Chemical Co., Ltd.): 4.0 parts by mass (D) Vinyl tris (methylethylketooxyimino) silane: 2.64 parts by mass (e) Platinum catalyst SRX212 (manufactured by Dow Corning Toray Co., Ltd., 6.0% by mass of platinum catalyst): 6.17 parts by mass (f) "Isopar" E (manufactured by Esso Chemical Co., Ltd.): 900 parts by mass. The compounding amount (parts by mass) of each component of the ink repellent layer composition-3 is 1 part of the total mass of the components (a) to (e). 0 indicated as parts by weight.

When the obtained lithographic printing plate precursor-32 was evaluated by the above method, the reflected light density difference was 1.30, the laser output required for development was 120 mJ / cm ² , and the silicone peeling resistance was 10 points. The result was obtained.

[Example 33]
A lithographic printing plate precursor-33 was obtained in the same manner as in Example 22, except that the ink repulsion layer composition-1 was changed to the following ink repulsion layer composition-4.

<Ink repellent layer composition-4>
(A) α, ω-divinylpolydimethylsiloxane: DMS-V35 (weight average molecular weight 49,500, manufactured by Gelest Inc.): 57.88 parts by mass (b) Methyl hydrogen siloxane RD-1 (Dow Corning Toray) 3.31 parts by mass (c) Silicone oil: KF-96-50cs (weight average molecular weight: 3,780, boiling point:> 150 ° C, Shin-Etsu Chemical Co., Ltd.): 30.0 parts by mass (D) Vinyl tris (methylethylketooxyimino) silane: 2.64 parts by mass (e) Platinum catalyst SRX212 (manufactured by Dow Corning Toray Co., Ltd., 6.0% by mass of platinum catalyst): 6.17 parts by mass (f) "Isopar" E (manufactured by Esso Chemical Co., Ltd.): 900 parts by mass. The compounding amount (parts by mass) of each component of the ink repellent layer composition-4 is the total mass of the components (a) to (e). 00 indicated as parts by weight.

When the obtained lithographic printing plate precursor-33 was evaluated by the above method, the reflected light density difference was 1.30, the laser output required for development was 100 mJ / cm ² , and the silicone peeling resistance was 8 points. The result was obtained.

[Example 34]
A lithographic printing plate precursor-34 was obtained in the same manner as in Example 22, except that the ink repulsion layer composition-1 was changed to the following ink repulsion layer composition-5.

<Ink repellent layer composition-5>
(A) α, ω-divinylpolydimethylsiloxane: DMS-V35 (weight average molecular weight 49,500, manufactured by GELEST Inc.): 53.15 parts by mass (b) Methyl hydrogen siloxane RD-1 (Dow Corning Toray) Co., Ltd.): 3.04 parts by mass (c) Silicone oil: KF-96-50cs (weight average molecular weight: 3,780, boiling point:> 150 ° C., manufactured by Shin-Etsu Chemical Co., Ltd.): 35.0 parts by mass (D) Vinyl tris (methylethylketooxyimino) silane: 2.64 parts by mass (e) Platinum catalyst SRX212 (manufactured by Dow Corning Toray Co., Ltd., 6.0% by mass of platinum catalyst): 6.17 parts by mass (f) "Isopar" E (manufactured by Esso Chemical Co., Ltd.): 900 parts by mass The compounding amount (parts by mass) of each component of the ink repellent layer composition-5 is determined by adding the total mass of the components (a) to (e). 00 indicated as parts by weight.

When the obtained lithographic printing plate precursor-34 was evaluated by the above method, the reflected light density difference was 1.30, the laser output required for development was 100 mJ / cm ² , and the silicone peeling resistance was 7 points. Obtained.

[Comparative Example 1]
After providing a base layer and a heat-sensitive layer in the same manner as in Example 1, an ink repellent layer was provided in the same manner as in Example 1 without providing a colored layer, and a lithographic printing plate precursor-35 was obtained.

When the obtained lithographic printing plate precursor-35 was evaluated by the above method, the reflected light density difference was 0.14, the laser output required for development was 180 mJ / cm ² , the silicone peeling resistance was 10 points, and the reflected light density difference was obtained. From the point of view, the result was impractical.

[Comparative Example 2]
A lithographic printing plate precursor-36 was obtained in the same manner as in Comparative Example 1, except that the heat-sensitive layer composition-1 was changed to the following heat-sensitive layer composition-2.

<Thermosensitive layer composition-2>
(A) Methylated melamine resin: "CYMEL" 303 (manufactured by Allnex): 53.2 parts by mass (b) Nitrocellulose: "Walsroder E400 NC" (manufactured by Dow Chemical): 18.5 parts by mass (c) Infrared absorbing compound : "S0094" (manufactured by FEW Chemicals GmbH): 24.0 parts by mass (d) sulfonic acid compound: p-toluenesulfonic acid: 4.3 parts by mass (e) propylene glycol methyl ether: 465 parts by mass (f) N- Methylpyrrolidone: 89 parts by mass The compounding amount (parts by mass) of each component of the above-mentioned thermosensitive layer composition-2 is shown assuming that the total mass of components (a) to (d) is 100 parts by mass.

When the obtained lithographic printing plate precursor-36 was evaluated by the above method, the difference in reflected light density was 0.20, the laser output required for development was 120 mJ / cm ² , the silicone peeling resistance was 6 points, and the reflected light density was The result was impractical due to the difference.

[Comparative Example 3]
Lithographic printing plate precursor-37 was obtained in the same manner as in Comparative Example 1, except that the heat-sensitive layer composition-1 was changed to the following heat-sensitive layer composition-3.

<Thermosensitive layer composition-3>
(A) Methylated melamine resin: "CYMEL" 303 (manufactured by Allnex): 36.4 parts by mass (b) Nitrocellulose: "Walsroder E400 NC" (manufactured by Dow Chemical): 12.7 parts by mass (c) Infrared absorbing compound : "S0094" (manufactured by FEW Chemicals GmbH): 48.0 parts by mass (d) Sulfonic acid compound: p-toluenesulfonic acid: 2.9 parts by mass (e) Propylene glycol methyl ether: 465 parts by mass (f) N- Methylpyrrolidone: 89 parts by mass The compounding amount (parts by mass) of each component of the heat-sensitive layer composition-3 is shown assuming that the total mass of the components (a) to (d) is 100 parts by mass.

When the obtained lithographic printing plate precursor-37 was evaluated by the above method, the difference in reflected light density was 0.25, the laser output required for development was 80 mJ / cm ² , the silicone peeling resistance was 2 points, and the reflected light density was The results were impractical due to differences and silicone peel resistance.

  Table 1 summarizes the above evaluation results.

Claims (15)

At least on the substrate
A heat-sensitive layer containing an infrared absorbing compound,
A lithographic printing plate precursor having an ink repellent layer in this order,
In the lithographic printing plate obtained by exposing and developing the lithographic printing plate precursor, the difference between the reflected light density of the unexposed portion and the reflected light density of the exposed portion, which is required on the exposed surface side, is 0.3 to 1.5. A lithographic printing plate precursor characterized in that: The lithographic printing plate according to claim 1, wherein a layer containing a dye compound and containing no infrared absorbing compound (such a layer is referred to as a colored layer) is provided between the heat-sensitive layer and the ink repellent layer. Printing plate original. The lithographic printing plate precursor according to claim 2, wherein the coloring layer contains 5 to 50% by mass of the coloring layer when the mass of the coloring layer containing the coloring compound is 100% by mass. . The lithographic printing plate precursor according to claim 2, wherein the color layer has a thickness of 0.5 to 3.0 μm. The lithographic printing plate precursor according to any one of claims 2 to 4, wherein a polymer having active hydrogen is contained in the colored layer. The lithographic printing plate precursor according to any one of claims 2 to 5, wherein a crosslinking agent is contained in the colored layer. The lithographic printing plate precursor according to any one of claims 2 to 6, wherein a non-dye compound having a property of thermally decomposing without undergoing melting is contained in the colored layer. The lithographic printing plate precursor according to any one of claims 2 to 6, wherein the dye compound has a property of being thermally decomposed without undergoing melting. The lithographic plate according to any one of claims 2 to 8, wherein the dye compound is at least one compound selected from the group consisting of triphenylmethane dyes, thiazine dyes, azo dyes, and compounds belonging to xanthene dyes. Printing plate original. The lithographic printing plate precursor according to any one of claims 1 to 9, wherein the ink repellent layer contains an ink repellent liquid, and the boiling point of the ink repellent liquid at 1 atm is 150 ° C or higher. The lithographic printing plate precursor according to claim 10, wherein the content of the ink repellent liquid is 4% by mass or more and 30% by mass or less when the mass of the ink repellent layer is 100% by mass. (A) a step of irradiating the lithographic printing plate precursor according to any one of claims 1 to 11 with an actinic ray to form a latent image on the lithographic printing plate precursor; and, if necessary, after the step (A). And (B) applying physical friction to the exposed lithographic printing plate precursor to remove the ink repellent layer. 13. The lithographic printing method according to claim 12, wherein in the step (B) of removing the ink repellent layer by applying physical friction to the exposed lithographic printing plate precursor, a physical friction is applied with a liquid interposed therebetween. Plate production method. The method according to claim 13, wherein the liquid is water or an aqueous solution. A step of attaching ink to the surface of a lithographic printing plate obtained by the method for producing a lithographic printing plate according to any one of claims 12 to 14, and a step of transferring the ink to a printing medium directly or via a blanket. And a method for producing a printed matter.