JP5529061B2 - Thermal lithographic printing plate - Google Patents

Description

  The present invention relates to a heat-sensitive lithographic printing plate using an image forming layer that undergoes phase conversion by heat, and relates to a heat-sensitive lithographic printing plate that does not require a layer removal process such as a conventional ablation method or an on-machine development method.

  In recent years, various plate making methods of planographic printing plates using various digital printers have been proposed with the development of computers and peripheral devices. For example, Japanese Patent Application Laid-Open Nos. 6-138719 and 6-250424 disclose plate making using a dry electrophotographic laser printer, and Japanese Patent Application Laid-Open No. 9-58144 includes on-demand using hot-melt ink. A plate making by an ink jet printer, and a plate making by a thermal printer using a thermal transfer ink ribbon are known from JP-A 63-166590.

  The plate making method using the printer as described above is roughly divided from the conventional optical mode type using a visible light laser or the like, and has an advantage that it is not restricted by safety light in handling. In addition, printing plates made by these plate making methods are collectively referred to as processless printing plates because they do not require post-exposure development processing that is normally used in conventional optical mode types.

  However, all of the above processless printing plates are formed by forming a printing plate by transferring and imparting a grease-sensitive (that is, lithographic printing ink setting property) recorded image to the surface of a support provided with a water retention layer. Therefore, there were the following problems.

1) Since a layer for forming an image is hydrophilic, adhesion of toner, ink or the like is not sufficient. For example, the transfer toner image density is insufficient, or white spots occur in the transferred image.
2) A problem that the transfer image is not sufficiently fixed, the printing durability is lowered, and in particular, a part of a small point character or a halftone image in a highlight portion is lost.
3) There is a problem in that a thin background smear is generated as a result of a small amount of toner being irregularly transferred to the non-image area or the thermal transfer ink ribbon being rubbed.

  On the other hand, we propose a processless printing plate that provides an oleophilic image area by providing an image-forming layer containing a thermoplastic resin or a heat-meltable substance on a support and performing thermal printing with a thermal head or infrared laser. Has been.

  For example, Japanese Patent Application Laid-Open No. 58-199153 (Patent Document 1) or Japanese Patent Application Laid-Open No. 59-174395 (Patent Document 2) directly draws heat on an image forming layer with a thermal head or the like without using a thermal transfer ribbon or the like. A heat-sensitive lithographic printing plate from which an oleophilic image area can be obtained is described. JP-A-2000-190649 (Patent Document 3) and JP-A-2000-301846 (Patent Document 4) describe a thermosensitive lithographic printing plate in which an oleophilic image portion is obtained by drawing with heat using an infrared laser or the like. Is described. In normal lithographic printing, both water and ink are simultaneously supplied to the oleophilic image area obtained as described above, and the image area accepts colored ink, and the other non-image areas are hydrophilic. Printing is performed by selectively receiving water and transferring the ink received on the image onto a printing medium such as paper.

  However, these heat-sensitive lithographic printing plates generally do not have a sufficient lipophilic / hydrophilic difference between the image area and the non-image area, so that it is difficult to obtain a clear printed image and the printing durability is insufficient. , Had a problem that soiling is likely to occur.

  Japanese Patent Laid-Open No. 63-64747 (Patent Document 5) proposes a method in which an inorganic pigment, a thermoplastic resin and a heat-meltable substance are contained in an image forming layer as a heat-sensitive lithographic printing plate capable of obtaining a clear and high image density. Has been. The thermosensitive lithographic printing plates described in Patent Document 3 and Patent Document 4 described above are made of a heat-meltable substance that exhibits lipophilicity in order to improve the balance between the lipophilicity of the image area and the hydrophilicity of the non-image area. A method of coating with a substance having a specific thermal conductivity and a technique of hydrophobizing the hydrophilic group of a hydrophilic polymer using a chelate reaction by heat are also disclosed. However, in both cases, it is difficult to control the reaction, and the difference in lipophilicity / hydrophilicity between the image area and the non-image area is not sufficient. The remaining.

  With respect to problems such as printing durability and background stains, Japanese Patent Application Laid-Open No. 11-95417 (Patent Document 6) uses a crosslinked hydrophilic resin such as polyvinyl alcohol or carboxymethyl cellulose in the image forming layer. Although it is described that the property and water retention are improved, since the phase conversion of the hydrophilic resin itself is utilized, the level of lipophilicity in the image area is low, and the difference between lipophilicity / hydrophilicity is It was not enough. JP-A-2000-75471 (Patent Document 7) uses a thermoplastic resin, a wax dispersion, a water repellent or the like as a hydrophobic substance, and uses gelatin, polyvinyl alcohol or the like as a hydrophilic substance. However, the difference in lipophilicity / hydrophilicity was not sufficient.

  Japanese Patent Application Laid-Open No. 5-200966 (Patent Document 8) provides a first heat-sensitive layer and a second heat-sensitive layer in this order on a support, the second heat-sensitive layer contains an inorganic pigment, and the first heat-sensitive layer. Describes a thermosensitive lithographic printing plate which does not contain inorganic pigments. However, one of the first heat-sensitive layer and the second heat-sensitive layer is an ink-philic resin layer, and one of them is an ink-repellent resin layer, and the heat-sensitive lithographic printing plate is subjected to thermal printing on the second heat-sensitive layer. The removed part is peeled off together with the coating film. The printing performance of the printing plate to be made is dependent on the peeling removal process, and the instability of the peeling removal has a problem of causing printing trouble. In addition, in an on-press development type thermal lithographic printing plate that removes a non-image part on a printing press, JP-A-2004-188890 (Patent Document 9) discloses a hydrophilic layer and an image on a support. Japanese Patent Application Laid-Open No. 2005-28774 (Patent Document 10) and Japanese Patent Application Laid-Open No. 2005-309417 (Patent Document 11) have a forming layer and the image forming layer contains heat-meltable particles and a filler. The technology to add an inorganic pigment as a filler in the image forming layer has been introduced, but because it is a type that peels off the non-image part on the printing press, there is a deposit of peeled material on the ink roller, etc. It was a problem that printability could not be secured. Accordingly, there is a need for a heat-sensitive lithographic printing plate that uses an image forming layer that undergoes phase conversion by heat and that does not require layer removal processing such as an ablation method or an on-press development method, and that has good printing durability and stain resistance. It was.

JP 58-199153 A JP 59-174395 A JP 2000-190649 A Japanese Patent Laid-Open No. 2000-301846 JP-A 63-64747 JP-A-11-95417 JP 2000-75471 A Japanese Patent Laid-Open No. 5-200966 JP 2004-188890 A JP 2005-28774 A JP 2005-309417 A

  In view of the above problems, an object of the present invention is to maintain a sufficient stain resistance and improve printing durability, and does not require a layer removal process such as an ablation method or an on-machine development method, and is capable of being phased by heat. It is an object of the present invention to provide a heat-sensitive lithographic printing plate using an image forming layer to be converted.

The above problems have been solved by the following means.
(1) It has at least two image forming layers containing a water-soluble polymer compound and a thermoplastic resin on a support, and an image forming layer far from the support contains an organic filler. Thermal lithographic printing plate.

  According to the present invention, an image forming layer that undergoes phase conversion by heat and that does not require layer removal processing such as an ablation method or an on-press development method while maintaining sufficient stain resistance and improved printing durability is used. A heat-sensitive lithographic printing plate can be provided.

  The heat-sensitive lithographic printing plate of the present invention has an image forming layer containing a water-soluble polymer compound and a thermoplastic resin. When the image forming layer is heated and drawn with a thermal head or an infrared laser, the thermoplastic resin embedded in the water-soluble polymer compound melts at the part where heat is applied, and the elution is converted in a form that partly oozes out to the extreme surface of the layer. It becomes possible to accept ink at the time of printing. The thermoplastic resin at the site where heat is not applied remains buried in the water-soluble polymer compound, and maintains the hydrophilicity originally possessed by the image forming layer.

  In the present invention, two image forming layers containing a water-soluble polymer compound and a thermoplastic resin are provided. The image forming layer closer to one support is the image forming layer (A), and the other is the image forming layer (B) far from the support. The heat-sensitive lithographic printing plate of the present invention contains an organic filler in the image forming layer (B) on the side far from the support. The present invention is described in detail below.

  The organic filler contained in the image forming layer (B) of the present invention has a glass transition point of 200 ° C. or higher, and is preferably insoluble or hardly soluble in general solvents. preferable. Furthermore, the material of the organic filler is preferably a crosslinked polystyrene resin, a crosslinked acrylic resin, a benzoguanamine resin, or a crosslinked silicone resin. Specifically, examples of the crosslinked polystyrene-based fine particles include those commercially available such as SX series manufactured by Soken Chemical Co., Ltd., and technopolymer SBX series manufactured by Sekisui Plastics. Examples of the crosslinked acrylic resin-based fine particles include commercially available MR series, MX series, SX series, Sekisui Plastics technopolymer MBX series, BMX series, and the like. Examples of the benzoguanamine resin-based fine particles include commercially available products such as the Nippon Catalysts & Chemicals Eposter GP series. Examples of the crosslinked silicone resin-based fine particles include commercially available products such as Tospearl series manufactured by Montive Performance Materials and KMP series manufactured by Shin-Etsu Chemical Co., Ltd. Any of these can be preferably used in the present invention.

  There is a preferable range for the average particle size of the organic filler contained in the image forming layer (B) of the present invention, and a range of 0.1 to 5.0 μm is preferable. Further, the content of the organic filler contained in the image forming layer (B) is preferably 0.01 to 40% by mass, more preferably 0.05 to 30% by mass, based on the total solid content of the image forming layer (B). is there.

  Examples of the water-soluble polymer compound contained in the image forming layer (A) and the image forming layer (B) of the present invention include proteins such as gelatin and gelatin derivatives, or cellulose derivatives, starch, gum arabic, dextran, pullulan and the like. Examples include natural compounds such as sugars and synthetic polymer compounds such as polyvinyl alcohol, modified polyvinyl alcohol, polyvinyl pyrrolidone, styrene / maleic acid copolymer salts, styrene / acrylic acid copolymer salts, and acrylamide polymers. These water-soluble polymer compounds may be used alone or in combination of two or more.

  The thermoplastic resin to be included in the image forming layer (A) and the image forming layer (B) of the present invention is a solid organic polymer compound made of a chain polymer and exhibiting plasticity upon heating, and the organic polymer compound Refers to an aqueous dispersion. Representative examples are synthetic rubber latex including modified products such as styrene butadiene copolymer, acrylonitrile butadiene copolymer, methyl methacrylate butadiene copolymer, styrene acrylonitrile butadiene copolymer, styrene methyl methacrylate butadiene copolymer. Styrene maleic anhydride copolymer, methyl vinyl ether maleic anhydride copolymer, polystyrene, styrene / acrylic acid ester copolymer, polyacrylic acid ester, polymethacrylic acid ester, acrylic acid ester / methacrylic acid ester copolymer Polymers and aqueous dispersions such as low melting point polyamide resins can also be used. These thermoplastic resins can be used alone or in combination of two or more. In view of the affinity with the printing ink vehicle (binder component), the thermoplastic resin is preferably a synthetic rubber latex, and in particular, a styrene-butadiene copolymer and a modified product thereof are desirable. A preferable blending amount of the thermoplastic resin is preferably 5 to 50% by mass with respect to the solid content of all the image forming layers.

  In order to easily develop the effect of melting and fusing by heat, it is preferable to use a thermoplastic resin having a glass transition point of 50 to 150 ° C, more preferably 55 to 120 ° C. If the glass transition temperature is less than 50 ° C., a phase change occurs in the liquid state during the production process, and hydrophobicity is developed even in the non-image area, which may cause printing stains. When the temperature exceeds 150 ° C., the polymer is hardly melted by heat, and it may be difficult to form a strong image with a relatively small output laser or a small thermal printer.

  The content ratio of the thermoplastic resin to the water-soluble polymer compound (mass of thermoplastic resin / total mass of the water-soluble polymer compound) in the image forming layer (A) of the present invention is 0.1 to 50. More preferably, it is 1-20. The content ratio of the thermoplastic resin to the water-soluble polymer compound (the mass of the thermoplastic resin / the total mass of the water-soluble polymer compound) in the image forming layer (B) is preferably 0.01 to 10, and Preferably it is 0.1-3. The content ratio of the thermoplastic resin to the water-soluble polymer compound in the image forming layer (A) is preferably higher than the content ratio in the image forming layer (B). Furthermore, it is more preferable that the difference between the content ratio in the image forming layer (A) and the content ratio in the image forming layer (B) is 0.5 or more. By adjusting to such a range, a heat-sensitive lithographic printing plate excellent in printing durability and stain resistance can be obtained.

  The image forming layer (A) and the image forming layer (B) of the present invention preferably contain a hot-melt material. Examples of the hot-melt material include compounds represented by the following general formulas (1) to (4) and waxes such as carnauba wax, microcrystalline wax, paraffin wax, polyethylene wax, lauric acid, stearic acid, oleic acid, palmitic acid. It is preferable to use fatty acids such as acid, behenic acid and montanic acid, and waxes such as esters and amides according to the purpose. Of these, organic compounds having a melting point of 50 to 150 ° C. are preferably used. If the melting point is less than 50 ° C., it will melt during the production process, which may cause soiling of the printed matter. On the other hand, when the temperature exceeds 150 ° C., it is difficult to melt by application of heat from a thermal head or the like, and the occurrence of image toughness or the expression of lipophilicity may be poor. A preferable blending amount of the heat-meltable substance is preferably 1 to 50% by mass, more preferably 10 to 30% by mass with respect to the total solid content of the image forming layer.

  The compound represented by the general formula (1) will be described below.

In the above formula, X ₁ represents —O— or —CO—O—, and R _{1 to} R ₆ each represents a hydrogen atom, an alkyl group, or an aryl group. n represents an integer of 1 to 10, and the substituents R _{1 to} R ₃ and R _{4 to} R ₆ may be bonded to each other to form an aromatic ring.

Among the compounds represented by the general formula (1), compounds in which X ₁ is —O— are preferable, and R ₁ and R ₆ are particularly a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and R _{2 to} R _5. A compound in which is a hydrogen atom and n is an integer of 1 to 4 is particularly preferably used.

Examples of the compound represented by the general formula (1) include the following compounds, but are not limited thereto.
(1) 1- (1-naphthoxy) -2-phenoxyethane (2) 1- (2-naphthoxy) -4-phenoxybutane (3) 1- (2-isopropylphenoxy) -2- (2-naphthoxy) ethane (4) 1- (4-Methylphenoxy) -3- (2-naphthoxy) propane (5) 1- (2-methylphenoxy) -2- (2-naphthoxy) ethane (6) 1- (3-methylphenoxy ) -2- (2-naphthoxy) ethane (7) 1- (2-naphthoxy) -2-phenoxyethane (8) 1- (2-naphthoxy) -6-phenoxyhexane (9) 1-phenoxy-2- ( 2-phenylphenoxy) ethane (10) 1- (2-methylphenoxy) -2- (4-phenylphenoxy) ethane (11) 1,4-diphenoxybutane (12) 1,4-bis (4-methylphenyl) Noxy) butane (13) 1,2-bis (3,4-dimethylphenoxy) ethane (14) 1-phenoxy-3- (4-phenylphenoxy) propane (15) 1- (4-tert-butylphenoxy)- 2-phenoxyethane (16) 1,2-diphenoxyethane (17) 1- (4-methylphenoxy) -2-phenoxyethane (18) 1- (2,3-dimethylphenoxy) -2-phenoxyethane (19 ) 1- (3,4-dimethylphenoxy) -2-phenoxyethane (20) 1- (4-ethylphenoxy) -2-phenoxyethane (21) 1- (4-isopropylphenoxy) -2-phenoxyethane (22 ) 1,2-bis (2-methylphenoxy) ethane (23) 1- (2-methylphenoxy) -2- (4-methylphenoxy) ethane (24) 1- (4-tert-Butylphenoxy) -2- (2-methylphenoxy) ethane (25) 1,2-bis (3-methylphenoxy) ethane (26) 1- (3-methylphenoxy) -2- ( 4-methylphenoxy) ethane (27) 1- (4-ethylphenoxy) -2- (3-methylphenoxy) ethane (28) 1,2-bis (4-methylphenoxy) ethane (29) 1- (2, 3-Dimethylphenoxy) -2- (4-methylphenoxy) ethane (30) 1- (2,5-dimethylphenoxy) -2- (4-methylphenoxy) ethane (31) Phenoxyacetic acid-2-naphthyl (32) 2-Naphoxyacetic acid-4-methylphenyl (33) 2-naphthoxyacetic acid-3-methylphenyl

  Next, the compound represented by the general formula (2) will be described.

In the above formula, R ₇ represents an alkyl group, an aryl group, an alkylcarbonyl group, an arylcarbonyl group, an alkylsulfonyl group, or an arylsulfonyl group. The naphthalene ring in the formula may further have a substituent, and examples of preferable substituents include an alkyl group, an aryl group, a halogen group, a hydroxy group, an alkoxy group, an aryloxy group, and an alkyloxycarbonyl group. , Alkoxycarbonyl group, aryloxycarbonyl group, carbamoyl group, sulfamoyl group and the like.

Among the substituents represented by R ₇ in the general formula (2), an alkyl group having 4 to 20 carbon atoms, an aryl group having 6 to 24 carbon atoms, an alkylcarbonyl group having 2 to 20 carbon atoms, and 7 to 20 carbon atoms. The arylcarbonyl group is more preferable. In the general formula (2), among the substituents that the naphthalene ring may further have, a halogen group, an alkyl group having 1 to 10 carbon atoms, an alkyloxycarbonyl group having 2 to 20 carbon atoms, or a 7 to 20 carbon atom. An aryloxycarbonyl group and a carbamoyl group having 2 to 25 carbon atoms are more preferable.

Examples of the compound represented by the general formula (2) include the following compounds, but are not limited thereto.
(1) 1-benzyloxynaphthalene (2) 2-benzyloxynaphthalene (3) 2-p-chlorobenzyloxynaphthalene (4) 2-p-isopropylbenzyloxynaphthalene (5) 2-dodecyloxynaphthalene (6) 2 Decanoyloxynaphthalene (7) 2-Myristoyloxynaphthalene (8) 2-p-tert-butylbenzoyloxynaphthalene (9) 2-Benzoyloxynaphthalene (10) 2-Benzyloxy-3-N- (3-dodecyl Oxypropyl) carbamoylnaphthalene (11) 2-benzyloxy-3-N-octylcarbamoylnaphthalene (12) 2-benzyloxy-3-dodecyloxycarbonylnaphthalene (13) 2-benzyloxy-3-p-tert-butylphenoxy Carbonyl naphthalene

  Next, the compound represented by the general formula (3) will be described.

In the above formula, R ₈ and R ₉ represent a hydrogen atom, a halogen group, an alkyl group having 4 or less carbon atoms, or an alkoxy group. X ₂ represents a simple bond or —O—, and n represents an integer of 1 to 4.

Examples of the compound represented by the general formula (3) include, but are not limited to, the following compounds.
(1) dibenzyl oxalate (2) bis (p-methylbenzyl) oxalate
(3) Bisoxalate (p-chlorobenzyl)
(4) Bisoxalate (m-methylbenzyl)
(5) Bisoxalate (p-ethylbenzyl)
(6) Bisoxalate (p-methoxybenzyl)
(7) Bisoxalate (2-phenoxyethyl)
(8) Bis oxalate (2-o-chlorophenoxyethyl)
(9) Bis oxalate (2-p-chlorophenoxyethyl)
(10) Bis-oxalate (2-p-ethylphenoxyethyl)
(11) Bisoxalate (2-m-methoxyphenoxyethyl)
(12) Bisoxalate (2-p-methoxyphenoxyethyl)
(13) Bis-oxalate (4-phenoxybutyl)

  Among these exemplified compounds, preferred specific examples include dibenzyl oxalate, bis (p-methylbenzyl) oxalate, bis (p-chlorobenzyl) oxalate, bis (m-methylbenzyl) oxalate, and bisoxalate. (P-ethylbenzyl) and bis (p-methoxybenzyl) oxalate.

  The compound represented by the general formula (4) will be described below.

In the above formula, R ₁₀ , R ₁₀ ′, R ₁₁ and R ₁₁ ′ represent a hydrogen atom, a halogen atom, an alkyl group, an aryl group, an alkoxy group, an alkylcarbonyl group, an arylcarbonyl group, an alkoxycarbonyl group, or an aryloxy group. .

Examples of the compound represented by the general formula (4) include the following compounds, but are not limited thereto.
(1) 1,2-bisphenoxymethylbenzene (2) 1,3-bisphenoxymethylbenzene (3) 1,4-bis (2-methylphenoxymethyl) benzene (4) 1,4-bis (3-methyl Phenoxymethyl) benzene (5) 1,3-bis (4-methylphenoxymethyl) benzene (6) 1,3-bis (2,4-dimethylphenoxymethyl) benzene (7) 1,3-bis (2,6 -Dimethylphenoxymethyl) benzene (8) 1,4-bis (2-chlorophenoxymethyl) benzene (9) 1,2-bis (4-chlorophenoxymethyl) benzene (10) 1,3-bis (4-chloro Phenoxymethyl) benzene (11) 1,2-bis (4-octylphenoxymethyl) benzene (12) 1,3-bis (4-octylphenoxymethyl) benzene 13) 1,3-bis [4- (4-isopropylphenyl) phenoxymethyl] benzene (14) 1,4-bis [4- (4-isopropylphenyl) phenoxymethyl] benzene

  Preferred examples among these exemplary compounds include 1,2-bisphenoxymethylbenzene, 1,4-bis (2-methylphenoxymethyl) benzene, 1,4-bis (3-methylphenoxymethyl) benzene, 1,4-bis (2-chlorophenoxymethyl) benzene may be mentioned.

  Among the compounds represented by the general formulas (1) to (4), the compounds represented by the general formulas (1), (2), and (4) are preferable in that excellent printing durability can be obtained. The compounds represented by (1) and (2) are preferred, and the most preferred compound is the compound represented by the general formula (1). Moreover, about the said heat-meltable substance, each may be used independently and can also be used in combination. In addition, different heat-meltable substances can be used for the image forming layer (A) and the image forming layer (B). A preferred combination is to use the compounds represented by the general formulas (1) to (4) in combination with waxes.

  The compounds represented by the above general formulas (1) to (4) are solid substances at room temperature, but are preferably used after being subjected to a fine dispersion treatment in order to increase the reactivity with heat. As a fine dispersion treatment method, a bead mill such as a roll mill, a colloid mill, a ball mill, an attritor or a sand mill, which is a wet dispersion method generally used at the time of producing a paint, can be used. In the bead mill, ceramic beads such as zirconia, titania and alumina, metal beads such as chrome and steel, glass beads and the like can be used. The dispersed particle diameter is preferably from 0.1 to 1.2 μm in median diameter, particularly preferably from 0.3 to 0.8 μm. The median diameter is the particle diameter (cumulative average diameter) at which the cumulative curve becomes 50% when the total curve of one population of particles is 100%, and the particle size distribution is evaluated. As one of the parameters to be measured, it can be measured using a laser diffraction / scattering particle size distribution measuring apparatus LA920 (manufactured by Horiba, Ltd.) or the like.

  The image forming layer (A) and the image forming layer (B) of the present invention preferably contain a hardening agent (waterproofing agent) depending on the type of the water-soluble polymer compound. As a hardener, a material that imparts water resistance by accelerating the crosslinking of water-soluble polymer compounds such as melamine resin, epoxy resin, polyisocyanate compound, aldehyde compound, silane compound, chromium alum, divinyl sulfone, etc. Although it is possible, divinyl sulfone is particularly preferably used. The compounding amount of the hardener is preferably 0.01 to 30% by mass with respect to the solid content of the water-soluble polymer compound contained in the entire image forming layer, and more preferably 0.5 to It is in the range of 20% by mass.

  In the heat-sensitive lithographic printing plate of the present invention, a developer or a color former (electron donating property) such as a phenol derivative or an aromatic carboxylic acid derivative used for general heat-sensitive recording paper and pressure-sensitive recording paper for ensuring visibility. Dye precursor).

  Specific examples of the developer include 4-cumylphenol, hydroquinone monobenzyl ether, 4,4'-isopropylidenediphenol, 1,1-bis (4-hydroxyphenyl) cyclohexane, 4,4'- Dihydroxydiphenyl-2,2-butane, 4,4′-dihydroxydiphenylmethane, 2,2-bis (4-hydroxyphenyl) -4-methylpentane, 2,2-bis (4-hydroxyphenyl) heptane, bis (4 -Hydroxyphenylthioethoxy) methane, 1,5-bis (4-hydroxyphenylthio) -3-oxapentane, 1,1-bis (4-hydroxyphenyl) -1-phenylethane, 1,4-bis [α -Methyl-α- (4′-hydroxyphenyl) ethyl] benzene, 1,3-bis [α-methyl-α- (4′-hydride) Xylphenyl) ethyl] benzene, 4,4'-dihydroxydiphenyl sulfide, bis (4-hydroxy-3-methylphenyl) sulfine, 4-hydroxy-4'-methyldiphenylsulfone, 4-hydroxy-4'-isopropoxydiphenylsulfone 2,4'-dihydroxydiphenylsulfone, 4,4'-dihydroxydiphenylsulfone, bis (3-allyl-4-hydroxyphenyl) sulfone, 4-hydroxyphenyl-4'-benzyloxyphenylsulfone, 4-hydroxy-3 ', 4'-tetramethylenebiphenylsulfone, 3,4-dihydroxyphenyl-p-tolylsulfone, 4,4'-dihydroxybenzophenone, benzyl 4-hydroxybenzoate, N, N'-bis (m-chlorophenyl) thiourea , N- ( Phenolic compounds such as phenoxyethyl) -4-hydroxyphenylsulfonamide, zinc 4- [3- (p-tolylsulfonyl) propyloxy] salicylate, zinc 4- [2- (p-methoxyphenoxy) ethyloxy] salicylate, 5 -{P- [2- (p-methoxyphenoxy) ethoxy]) cumyl} zinc salicylate, zinc salts of aromatic carboxylic acids such as zinc p-chlorobenzoate, and organic acidic substances such as antipyrine complexes of zinc thiocyanate Etc. are exemplified.

  Specific examples of the color former (electron-donating dye precursor) include (1) 3,3′-bis (p-dimethylaminophenyl) -6-dimethylaminophthalide (Crystal Violet lactone), 3,3′-bis (p-dimethylaminophenyl) phthalide, 3- (p-dimethylaminophenyl) -3- (1,2-dimethylindol-3-yl) phthalide, 3- (p -Dimethylaminophenyl) -3- (2-methylindol-3-yl) phthalide, 3- (p-dimethylaminophenyl) -3- (2-phenylindol-3-yl) phthalide, 3,3-bis ( 1,2-dimethylindol-3-yl) -5-dimethylaminophthalide, 3,3-bis (1,2-dimethylindol-3-yl) -6-dimethyla Nophthalide, 3,3-bis (9-ethylcarbazol-3-yl) -5-dimethylaminophthalide, 3,3-bis (2-phenylindol-3-yl) -5-dimethylaminophthalide, 3- p-dimethylaminophenyl-3- (1-methylpyrrol-2-yl) -6-dimethylaminophthalide and the like: (2) 4,4'-bis (dimethylaminobenzhydrin) benzyl ether as a diphenylmethane compound N-halophenyl leucooramine, N-2,4,5-trichlorophenyl leucooramine, etc .: (3) As xanthene compounds, rhodamine B-anilinolactam, rhodamine Bp-nitroanilinolactam, rhodamine Bp-chloroanilinolactam, 3-diethylamino-7-dibenzylaminofluorane, 3-di Tilamino-7-octylaminofluorane, 3-diethylamino-7-phenylfluorane, 3-diethylamino-7- (3,4-dichloroanilino) fluorane, 3-diethylamino-7- (2-chloroanilino) fluorane, 3 -Diethylamino-6-methyl-7-anilinofluorane, 3-dibutylamino-6-methyl-7-anilinofluorane, 3-piperidino-6-methyl-7-anilinofluorane, 3- (N- Ethyl-N-4-methylphenyl) amino-6-methyl-7-anilinofluorane, 3- (N-ethyl-N-4-methylphenyl) amino-6-methyl-7-phenethylfluorane, 3 -Diethylamino-7- (4-nitroanilino) fluorane, etc .: (4) benzoylleucomethylene blue as thiazine compound P-nitrobenzoylleucomethylene blue and the like: (5) As a spiro compound, 3-methyl-spiro-dinaphthopyran, 3-ethyl-spiro-dinaphthopyran, 3,3'-dichloro-spiro-dinaphthopyran, 3-benzyl-spiro- Examples include dinaphthopyran, 3-methylnaphtho- (3-methoxybenzo) -spiropyran, and 3-propyl-spiro-dibenzopyran. These may be used alone or in combination of two or more.

  Furthermore, in the present invention, a photothermal conversion substance can be blended in the image forming layer. By using a photothermal conversion agent, writing with active light such as an infrared laser as well as a thermal head is possible. As an example of the photothermal conversion substance, a material that efficiently absorbs light and converts it into heat is preferable. Depending on the light source used, for example, when a semiconductor laser emitting near infrared light is used as the light source, Near-infrared light absorbers having an absorption band outside are preferable, for example, organic materials such as carbon black, cyanine dyes, polymethine dyes, azurenium dyes, squarylium dyes, thiopyrylium dyes, naphthoquinone dyes, anthraquinone dyes Examples thereof include metal compounds such as compounds, phthalocyanine-based, azo-based, and thioamide-based organometallic complexes, iron powder, graphite powder, iron oxide powder, lead oxide, silver oxide, chromium oxide, iron sulfide, and chromium sulfide.

  In addition, preservatives, surfactants, antifoaming agents, leveling agents, pH adjusting agents, other coating aids, and the like are also optionally added to the image forming layer (A) and the image forming layer (B) of the present invention. Can be added.

The image-forming layer of the heat-sensitive lithographic printing plate of the present invention has a dry solid content of 0.5 to 30 g / m ² from the viewpoints of printing durability of image areas, water resistance of non-image areas and mechanical strength. It is preferable. In addition, as a method for coating the image forming layer (A) and the image forming layer (B) in the present invention, the image forming layer (A) on the side close to the support is applied, and then the image forming layer (B) is applied. There are a method of sequentially applying and stacking, a method of simultaneously applying multiple layers by a slide hopper method, and any method may be used.

  As a preferable support used for the heat-sensitive lithographic printing plate of the present invention, a water-resistant support such as a plastic film, resin-coated paper, and water-resistant paper can be preferably used. Specifically, plastic films such as polyolefins such as polyethylene and polypropylene, polyethersulfone, polyester, poly (meth) acrylate, polycarbonate, polyamide, and polyvinyl chloride, and resin-coated paper with these plastics laminated or coated on the surface, melamine Paper that has been made water resistant by a wet paper strength agent such as formaldehyde resin, urea formaldehyde resin, or epoxidized polyamide resin can be suitably used.

  Next, a plate making method using the above-described heat-sensitive lithographic printing plate of the present invention will be described. Since the heat-sensitive lithographic printing plate of the present invention has a heat-sensitive image forming layer, it is possible to irradiate light containing infrared light of, for example, 760 nm to 1200 nm by blending a photothermal conversion material in the image forming layer. It is possible to form an image portion, and it is preferable to form the image portion with a solid laser and a semiconductor laser emitting infrared rays. In particular, laser exposure enables desired image-like recording directly from digital information of a computer. It is also possible to draw an image forming layer directly by heat with a thermal head or a heat block to form an image portion. However, the thermal head enables recording of a desired image directly from digital information of a computer. .

When plate making is performed using a thermal head, a line printer using a thick film or thin film line head, a serial printer using a thin film serial head, or the like can be used. The recording energy density is preferably 10 to 100 mJ / mm ² , and the head image recording density is preferably 300 dpi or more in order to obtain a relatively high quality output image.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, of course, this invention is not limited to this Example. In the following description, “%” and “part” represent a mass ratio unless otherwise specified.

On one side of a polyethylene resin-coated paper having a thickness of about 180 μm and laminated on both sides, an image forming layer a-1 and an image forming layer b-1 having the following composition (types and addition amounts of organic fillers are listed in Table 1) The coating solution was applied in the order of the image forming layer a-1 and the image forming layer b-1 (uppermost layer) from the support side by the slide hopper coating method. At this time, the wet coating amount, the image forming layer a-1 coating liquid 30 g / ^{m 2,} the image forming layer b-1 coating liquid was performed by setting the 10 g / ^{m 2.} Also, an image forming layer c coating solution for a single-layer comparative example was prepared, and similarly applied by applying a slide hopper coating method to 40 g / m ² .

<Image forming layer a-1 coating solution>
Gelatin (cow bone, alkali treatment, decalcification treatment) 0.8 part Polyvinyl alcohol: PVA505 0.07 part (manufactured by Kuraray Co., Ltd., saponification degree = 73.5 mol%, polymerization degree 500)
Carboxylated SBR: LUXSTAR 7132C 3.0 parts (manufactured by DIC Corporation, solid content = about 45%, anionic, Tg = about 60 ° C.)
Developer mixed slurry Solid solution 35% 8.0 parts Color developer: 0.7 parts (3-dibutylamino-6-methyl-7-anilinofluorane, 30% slurry)
Surfactant:
(Bis (2-ethylhexyl) sulfosuccinate Na, 4% solution) 0.4 part Hardener: (Divinylsulfone, 5% solution) 2.0 parts The total amount was 30 parts with water.

<Image forming layer b-1 coating solution>
Gelatin (cow bone, alkali treatment, decalcification treatment) 0.4 part Anionic acrylic resin: 0.1 part of MKB-7 (Arakawa Chemical Industries, Ltd. solid content 10% solution)
Carboxylated SBR: LUXSTAR 7132C 0.6 part (manufactured by DIC Corporation, solid content 45% solution, anionic, Tg = about 60 ° C.)
Organic filler: listed in Table 1. Addition amount in terms of solid amount X part Color former: 0.3 part (3-dibutylamino-6-methyl-7-anilinofluorane, 30% slurry)
Hot-melt material: 0.3 part of J-537 (manufactured by Chukyo Yushi Co., Ltd., 30% solid content solution)
Surfactant:
(Bis (2-ethylhexyl) sulfosuccinate Na, 4% solution) 0.2 part Hardener: (Divinylsulfone, 5% solution) 1.0 part The total amount was 10 parts with water.

<Image forming layer c coating solution>
Gelatin (cow bone, alkali treatment, decalcification treatment) 1.2 parts Polyvinyl alcohol: 0.1 part of PVA505 (manufactured by Kuraray Co., Ltd., saponification degree = 73.5 mol%, polymerization degree 500)
Carboxylated SBR: 3.5 parts of LUXSTAR 7132C (manufactured by DIC Corporation, solid content = about 45%, anionic, Tg = about 60 ° C.)
Organic filler: Tospearl 105 (silicone resin system) 0.01 parts Developer mixed slurry Solid solution 35% 6.0 parts Color developing agent: 0.7 parts (3-dibutylamino-6-methyl-7-anilinofur (Oran, 30% slurry)
Surfactant:
(Bis (2-ethylhexyl) sulfosuccinate Na, 4% solution) 0.6 part Hardener: (Divinylsulfone, 5% solution) 2.5 parts The total amount was 40 parts with water.

The developer mixed slurry used for the image forming layer a-1 coating solution and the image forming layer c coating solution was prepared and manufactured in advance with the following constituent chemicals.
<Constituent chemicals of developer mixed slurry>
Material a: KS-232
(Manufactured by Sanko Co., Ltd., hot-melt material, 1,2-bis (3-methylphenoxy) ethane)
Material b: D-8
(Nippon Soda Co., Ltd., developer, 4-hydroxy-4'-isopropoxydiphenyl sulfone)
Material c: Polymeron 1318
(Arakawa Chemical Industries, Ltd., dispersant, anionic styrene resin 15% solution)

  In water to which 0.7 part of the material c is added, 1 part of each of the material a and the material b is mixed under constant stirring, and then the median diameter is set to 0. 0 using zirconia beads in a small dyno mill (bead mill). A fine dispersion treatment was performed so as to be 6 μm to obtain a developer mixed slurry. In addition, it prepared so that solid content concentration in the sum total of the material a, the material b, and the material c might be 35%.

  After performing simultaneous multilayer coating and single layer coating at the above moisture coating amount, the coating film was immediately gelled with cold air of 1 to 3 ° C. and then dried with warm air set at 30 ° C. After drying, heat-sensitive lithographic printing plates 1 to 20 were obtained by heating for 7 days using a thermo-hygrostat adjusted to a temperature of 40 ° C./humidity of 40%.

The thermal lithographic printing plate produced as described above was subjected to image output using a thermal digital printer for CTP (Thermal Digiplater TDP-459: 1200 dpi / 120 lpi manufactured by Mitsubishi Paper Industries Co., Ltd.) (recording energy density 100 mJ / mm ² , electric A printing plate was prepared with a capacity of 330 W). Using this printing plate, printability was evaluated by the following method.

<Printing evaluation 1>
For printing evaluation for printing durability, HAMADAH234C (offset printing machine manufactured by Hamada Printing Co., Ltd.) is used as the printing machine, natural black black H type (DIC Corporation) is used as ink, and SLM is used as the dampening liquid. A 3% aqueous solution of OD30 (Mitsubishi Paper Co., Ltd. dampening solution) was used. Before starting printing, wipe the plate surface with a 25% aqueous solution of SLM-OD30 using absorbent cotton, and then apply a 0.05 mm gauge film between the plate cylinder and the plate for evaluation under forced conditions. Printing was carried out at a speed of 8000 sheets / hr with the printing pressure increased. The evaluation was carried out by visually evaluating the number of prints that could not be printed due to missing images in the printed material.
<Print durability>
A: More than 5,000 sheets O: Less than 4,000 to 5,000 △: Less than 2,000 to 4,000 sheets ×: Less than 2,000 sheets Table 2 shows the results.

<Printing evaluation 2>
For the printing evaluation for stain resistance, Ryobi 3200CCD (manufactured by Ryobi Imagics Co., Ltd.) is used as the printing machine, ink is New Champion FG Purple 68S (manufactured by DIC Corporation), and the dampening liquid is SLM-OD30 (Mitsubishi). A 2% aqueous solution of dampening liquid manufactured by Paper Manufacturing Co., Ltd. was used. Before starting printing, wipe the plate surface with a 15% aqueous solution of SLM-OD30 using absorbent cotton, and then use a 0.05 mm gauge film between the plate cylinder and the plate for evaluation under forced conditions. Printing was performed at a printing speed of 7000 sheets / hr with the sandwiching and the printing pressure increased, and the number of prints on the non-image area of the printed material was evaluated according to the following evaluation criteria.
<Stain resistance>
○: More than 2,000 sheets ×: Less than 2,000 results are shown in Table 2.

  As is apparent from the results in Table 2 above, it can be seen that the heat-sensitive lithographic printing plate of the present invention improves the printing durability without deteriorating the stain resistance as compared with the comparative example.

Claims (1)

  A heat-sensitive lithographic plate comprising at least two image-forming layers containing a water-soluble polymer compound and a thermoplastic resin on a support, and of which an image-forming layer far from the support contains an organic filler Printed version.