JP2016030360A - Thermosensitive lithographic printing plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thermosensitive lithographic printing plate that has excellent printing durability and scumming resistance, and improves image unevenness from head scum in the long-term use of a thermal head.SOLUTION: A thermosensitive lithographic printing plate has, on a support, at least two image formation layers each having a thermoplastic resin and a hydrophilic binder, wherein among the image formation layers, one that is farther from the support than the other contains zinc oxide or barium sulfate, and a surfactant having a perfluoroalkyl group.SELECTED DRAWING: None

Description

  The present invention relates to a heat-sensitive lithographic printing plate that forms an image by contact heating.

  The so-called contact heat transfer method, in which a heating element is drawn by contact heating, can be used as an image output device with a relatively simple configuration and is easy to downsize. It is widely known as a plate image forming method.

  A thermal head is generally used as a heating means for contact heating. In the thermal head, a plurality of resistance heating elements are arranged in a row in a direction (hereinafter referred to as a scanning direction) orthogonal to the conveyance direction of the heat-sensitive recording material, and one line in the scanning direction depends on the energization state of each heating element. Draw. An image is formed on the thermal recording material by sequentially conveying the thermal recording material and repeating one line drawing. As a method for transporting the thermal recording material, a method is generally used in which the thermal recording material is sandwiched between a thermal head, a platen roller, and a transport roller pair, and transported by rotating the platen roller and the transport roller pair. ing.

  As a problem in contact heating with a thermal head, image unevenness and sticking in the scanning direction caused by changes in adhesion and frictional resistance caused by melting and softening of the heat sensitive components, so-called head debris adheres to and accumulates on the thermal head. In addition, image unevenness in the conveying direction caused by heat transfer failure to the heat sensitive recording material or the like can be mentioned.

  A heat-sensitive recording material to be drawn by a contact heat transfer method generally has a heat-sensitive recording layer mainly composed of an electron-donating compound, usually a colorless or light-colored dye precursor, and an electron-accepting compound. For the purpose of eliminating image unevenness and sticking, there has been proposed a heat-sensitive recording material in which a protective layer to which various fillers are added is provided on the heat-sensitive recording layer. For example, JP-A-6-135149 (Patent Document 1) discloses a method of adding aluminum hydroxide, and JP-A-7-9762 (Patent Document 2) contains kaolin and silicon oxide. A method of using both in combination is disclosed, and JP 2002-240430 A (Patent Document 3) discloses a method of using amorphous silica in combination with at least one of kaolin or aluminum hydroxide. Further, in JP-A-2004-237605 (Patent Document 4), it is possible to use a fluorosurfactant having a perfluoroalkyl group as a surfactant for improving the slipperiness and surface quality of the overcoat layer. Furthermore, zinc oxide and barium sulfate are described as examples of the matting agent described and contained in the overcoat layer.

  Thermosensitive lithographic printing plates drawn by the contact heat transfer method are designed to form a hydrophobic (lipophilic) image by causing phase transformation by drawing with contact heating on the surface that was originally hydrophilic. Both water and ink are supplied at the same time, the image part accepts colored ink, and the other non-image part selectively accepts water because of hydrophilicity, and the ink received on the image part, For example, printing is performed by transferring it onto a printing medium such as paper. For this reason, the method of providing a protective layer proposed for a heat-sensitive recording material or the like causes a problem that printing performance is deteriorated.

  For example, International Publication No. 2011/048912 (Patent Document 5) has two image forming layers as a method for eliminating the image unevenness and sticking in the heat-sensitive lithographic printing plate. It is described that by making the ratio of the specific compound to the water-soluble polymer compound higher than that in the image forming layer far from the support, it is possible to improve defective printing due to the head residue in addition to sufficient printability. In addition, such a document describes that printing durability and stain resistance can be improved in a well-balanced manner by using barium sulfate or zinc oxide for an image forming layer far from the support.

  This makes it possible to greatly extend the period until the head residue adhering to the thermal head is cleaned. On the other hand, the head residue adhering to the thermal head is repeatedly heated due to the extended period until cleaning. However, it cannot be easily removed from the thermal head, and image unevenness may occur in the transport direction of the heat-sensitive lithographic printing plate, and improvement has been demanded.

JP-A-6-135149 JP-A-7-9762 Japanese Patent Laid-Open No. 2002-240430 JP 2004-237605 A International Publication No. 2011/048912 Pamphlet

  An object of the present invention is to provide a heat-sensitive lithographic printing plate that has excellent printing durability and background stain resistance, and has improved image unevenness due to head residue when a thermal head is used for a long time. is there.

  The above problem is that the support has at least two image forming layers containing a thermoplastic resin and a hydrophilic binder, and the image forming layer far from the support has zinc oxide or barium sulfate and a perfluoroalkyl group. It was basically achieved by a heat-sensitive lithographic printing plate characterized by containing a surfactant having

  According to the present invention, it is possible to provide a heat-sensitive lithographic printing plate which is excellent in printing durability and background stain resistance and in which image unevenness caused by head residue when a thermal head is used for a long time is improved.

Hereinafter, the thermosensitive lithographic printing plate of the present invention will be described in detail.

  The heat-sensitive lithographic printing plate of the present invention has at least two image forming layers containing a thermoplastic resin and a hydrophilic binder. When the image forming layer is heated and drawn with a thermal head, the thermoplastic resin buried in the hydrophilic binder melts at the part where heat is applied, and the hydrophobicity is obtained by elution conversion in a form that partly oozes out to the extreme surface of the layer. Appears and can accept ink during printing. The thermoplastic resin at the site where heat is not applied remains buried in the hydrophilic binder, and maintains the hydrophilicity originally possessed by the image forming layer.

  Hereinafter, the image forming layer closer to the support in the present invention is referred to as an image forming layer B, and the image forming layer far from the support is referred to as an image forming layer A. The image forming layer A contains zinc oxide or barium sulfate and a surfactant having a perfluoroalkyl group, which is a feature of the heat-sensitive lithographic printing plate of the present invention.

<Image forming layer A>
The image forming layer A of the present invention contains a thermoplastic resin, a hydrophilic binder, zinc oxide or barium sulfate, and a surfactant having a perfluoroalkyl group.

  The content of the surfactant having a perfluoroalkyl group is preferably 0.1% by mass or more, more preferably 0.17% by mass or more based on the total solid content of the image forming layer A. If the amount is less than 0.1% by mass, the effect of removing the head residue may not be sufficiently exhibited, and image unevenness may occur in the transport direction of the heat-sensitive lithographic printing plate. The upper limit is preferably 1.5% by mass or less, more preferably 1.0% by mass or less, based on the total solid content of the image forming layer A. If it exceeds 1.5% by mass, the printing durability is lowered, and there are cases where blurring or missing images appear in the printed image. Further, the content of the surfactant having a perfluoroalkyl group is particularly preferably 0.25 to 0.59% by mass with respect to the total solid content of the image forming layer A. This makes it possible to achieve both a reduction in image unevenness and printing durability at a higher level.

  In the present invention, as the surfactant having a perfluoroalkyl group contained in the image forming layer A, a perfluoroalkylethylene oxide compound and / or a perfluoroalkyl-containing oligomer can be used. Specifically, SURFLON S-242, S-243, S-420 (above, manufactured by AGC Seimi Chemical Co., Ltd.), MegaFuck F-444, TF-2066 (above, made by DIC Corporation) Perfluoroalkylethylene oxide adducts such as SURFLON S-611, S-651, S-386 (manufactured by AGC Seimi Chemical Co., Ltd.), MegaFuck F-472SF, F-477, F-553 Perfluoroalkyl-containing oligomers such as F-556, TF-1367, and TF-1437 (manufactured by DIC Corporation).

  Zinc oxide is roughly classified into a dry method and a wet method according to its production method. The dry method includes a French method and an American method, and the German method is well known as a wet method. The French method is a method in which zinc oxide is produced by heating high-purity metallic zinc and combusting generated zinc vapor in an oxidizing atmosphere. On the other hand, the American method is a method in which a reducing agent such as coke is added to zinc ore (flankite) and roasted, and the generated zinc vapor is oxidized by air to produce it. In addition, the wet method includes a method of thermally decomposing a zinc salt, such as zinc carbonate, a method of directly precipitating zinc oxide in a solution while neutralizing an alkaline solution of the zinc salt with an acid, an acidic solution of the zinc salt, There is a method of direct precipitation in the liquid while neutralizing the solution. In general, it is produced by reacting an acidic solution of zinc salt (zinc sulfate solution or zinc chloride solution) with an alkali such as soda ash, washing with water, filtering and drying, firing and pulverizing. Zinc oxide produced by these methods is commercially available from, for example, Shodo Chemical Industry Co., Ltd., Sakai Chemical Industry Co., Ltd., Hakusui Tech Co., Ltd., Honjo Chemical Co., Ltd., Toho Zinc Co., Ltd. Any of these can be used in the present invention.

  Barium sulfate is a precipitate produced by pulverizing barite and removing iron by washing and draining, and barium sulfate (barite powder) obtained by adding water and adding a sulfate aqueous solution to a barium chlorine solution to cause chemical precipitation. And barium sulfate. Examples of the barium sulfate produced by these methods include those commercially available from Sakai Chemical Industry Co., Ltd., Takehara Chemical Industry Co., Ltd., and Hakusui Tech Co., Ltd. Can be used in Furthermore, barium sulfate may be subjected to organic polymer treatment as a post-treatment after particle formation, and may be a hydroxide or oxide of any metal element such as Al, Si and Zr, Mg, Ca Surface treatment may be performed with a phosphate of any one of metal elements such as Sr and Ba.

  In the present invention, the image forming layer A is preferably the outermost layer (outermost layer), whereby excellent printability and the effect of suppressing image unevenness due to head residue can be achieved at a higher level. In this case, when the average particle diameter of zinc oxide or barium sulfate is too large, the contact area may decrease when printing is performed by directly contacting the image forming layer A with a thermal head. A reduction in the contact area may lead to a decrease in thermal efficiency and a decrease in printing durability. On the other hand, when the average particle size of zinc oxide or barium sulfate is too small, the effect of suppressing image unevenness is naturally reduced, but the contact area may be excessively increased depending on the particle size of zinc oxide or barium sulfate. In such a case, sticking resistance may be reduced due to a decrease in peelability. Therefore, the average particle diameter of zinc oxide or barium sulfate used in the present invention is preferably in the range of 0.1 to 1.0 μm, more preferably 0.2 to 0.5 μm.

  The shape of zinc oxide or barium sulfate used in the present invention may be any of an indefinite shape, a plate shape, a columnar shape, a granular shape, and the like.

  Further, there is a preferable range for the content of zinc oxide or barium sulfate contained in the image forming layer A, and it is preferably 10 to 50% by mass with respect to the amount of the thermoplastic resin contained in the image forming layer A. As a result, the printing durability and the effect of suppressing image unevenness can be achieved at a higher level. The total amount of the thermoplastic resin contained in the image forming layer A and the image forming layer B is preferably 10% by mass or less.

  Examples of the hydrophilic binder contained in the image forming layer A of the present invention include proteins such as gelatin and gelatin derivatives or cellulose derivatives, natural compounds such as polysaccharides such as starch, gum arabic, dextran and pullulan, polyvinyl alcohol, modified Examples thereof include synthetic polymer compounds such as polyvinyl alcohol, polyvinylpyrrolidone, styrene / maleic acid copolymer salt, styrene / acrylic acid copolymer salt, and acrylamide polymer. These hydrophilic binders may be used alone or in combination of two or more, but it is particularly preferred to use gelatin and polysaccharides in combination.

  Moreover, when using a hydrophilic binder together as mentioned above, there exists an optimal use ratio in each, and it is preferable to use a polysaccharide in 2-20 mass% with respect to 100 mass% of gelatin. The total amount of the hydrophilic binder contained in the image forming layer A is preferably 0.5 to 50% by mass with respect to the total solid content of the image forming layer A.

  The image forming layer A of the present invention preferably contains a hardening agent (waterproofing agent) depending on the type of the hydrophilic binder. As the hardener, those imparting water resistance by accelerating the crosslinking of the hydrophilic binder, such as melamine resin, epoxy resin, polyisocyanate compound, aldehyde compound, silane compound, chromium alum, and divinyl sulfone can be used. Particularly preferred is divinyl sulfone. The compounding amount of the hardener is preferably 1 to 30% by mass with respect to the solid content of the hydrophilic binder contained in the image forming layer A, and more preferably 2 to 15% by mass. is there.

  The thermoplastic resin contained in the image forming layer A is a solid organic polymer compound made of a chain polymer and exhibiting plasticity upon heating, and is added to the image forming layer coating liquid in the form of 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, polyacrylic acid copolymer, polystyrene, styrene / acrylic acid ester copolymer, polyacrylic acid ester, polymethacrylic acid ester, acrylic Aqueous dispersions such as acid ester / acrylic acid ester copolymers and 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 vehicle (binder component) of the printing ink, the thermoplastic resin is preferably a synthetic rubber latex, and particularly preferably a styrene butadiene copolymer and a modified product thereof. A preferable blending amount of the thermoplastic resin is preferably 5 to 50% by mass with respect to the solid content of the image forming layer A.

  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 temperature 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 a liquid state during the production process, and hydrophobicity is developed also in the non-image area, which may cause background stains on the printed matter. 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 hydrophilic binder in the image forming layer A (the mass of the thermoplastic resin / the total mass of the hydrophilic binder) is preferably 0.01 to 10, more preferably 0.1 to 0.1. 3.

  The image forming layer A preferably contains a heat-meltable substance. Examples of the hot-melt material include at least one selected from the compounds represented by the following general formulas (1) to (4), and waxes such as carnauba wax, microcrystalline wax, paraffin wax, polyethylene wax, It is preferable to use fatty acids such as lauric acid, stearic acid, oleic acid, palmitic 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 in the image forming layer 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 A.

  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 the present invention is 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 4 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 the present invention is 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 the following compounds, but the present invention is not limited thereto.
(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 the present invention is 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-isopropylphenyl phenoxymethyl) benzene (14) 1,4-bis (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.

  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, and glass beads 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.).

  There is a preferred range for the content ratio of the heat-meltable substance to the hydrophilic binder in the image forming layer A (mass of heat-meltable substance / mass of hydrophilic binder), and it is preferably 0 to 0.5.

  In the image forming layer A 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, di (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'-di-m-chlorophenylthiourea, N- (pheno Phenolic compounds such as xylethyl) -4-hydroxyphenylsulfonamide, zinc 4- [3- (p-tolylsulfonyl) propyloxy] salicylate, 4- [2- (p-methoxyphenoxy) ethyloxy] zinc salicylate, 5- [P- (2-p-methoxyphenoxyethoxy) cumyl] zinc salts of aromatic carboxylic acids such as zinc salicylate and zinc p-chlorobenzoate, and organic acidic substances such as antipyrine complexes of zinc thiocyanate The

  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 B -P-chloroanilinolactam, 3-diethylamino-7-dibenzylaminofluorane, 3- Ethylamino-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-ethyl- Tolylamino-6-methyl-7-anilinofluorane, 3-ethyl-tolylamino-6-methyl-7-phenethylfluorane, 3-diethylamino-7- (4-nitroanilino) fluorane, etc .: (4) thiazine compounds As benzoyl leucomethylene blue, p-nitrobenzoyl leucomethylene blue (5) As spiro compounds, 3-methyl-spiro-dinaphthopyrans, 3-ethyl-spiro-dinaphthopyrans, 3,3'-dichloro-spiro-dinaphthopyrans, 3-benzyl-spiro-dinaphthopyrans, 3-methylnaphtho- ( 3-methoxy-benzo) -spiropyran, 3-propyl-spiro-dibenzopyran and the like. 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 substance, 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 preferred, for example, organic materials such as carbon black, cyanine dyes, polymethine dyes, azurenium dyes, squalium 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 having no perfluoroalkyl groups, antifoaming agents, leveling agents, pH adjusting agents, other coating aids, and the like can be added as necessary.

<Image forming layer B>
The image forming layer B of the present invention contains a thermoplastic resin and a hydrophilic binder.

  Examples of the hydrophilic binder contained in the image forming layer B include proteins such as gelatin and gelatin derivatives or cellulose derivatives, natural compounds such as polysaccharides such as starch, gum arabic, dextran and pullulan, polyvinyl alcohol, modified polyvinyl alcohol, Examples thereof include synthetic polymer compounds such as polyvinyl pyrrolidone, styrene / maleic acid copolymer salt, styrene / acrylic acid copolymer salt, and acrylamide polymer. These hydrophilic binders may be used alone or in combination of two or more, but it is preferable to use gelatin and polyvinyl alcohol in combination.

  Moreover, when using a hydrophilic binder together as mentioned above, the optimal use ratio exists in each. As an optimal use ratio, it is preferable to use gelatin and polyvinyl alcohol in a range of 1 to 10% by mass of polyvinyl alcohol with respect to 100% by mass of gelatin.

  The image forming layer B of the present invention preferably contains a hardening agent (waterproofing agent) depending on the type of the hydrophilic binder. As the hardener, those imparting water resistance by accelerating the crosslinking of the hydrophilic binder, such as melamine resin, epoxy resin, polyisocyanate compound, aldehyde compound, silane compound, chromium alum, and divinyl sulfone can be used. Particularly preferably, divinyl sulfone is used. The blending amount of the hardener is preferably 1 to 30% by mass with respect to the solid content of the hydrophilic binder contained in the image forming layer B, and more preferably 2 to 15% by mass. is there.

  As the thermoplastic resin contained in the image forming layer B, the same compounds as those used in the image forming layer A can be used. The content ratio of the thermoplastic resin to the hydrophilic binder in the image forming layer B is preferably higher than the content ratio in the image forming layer A. Furthermore, it is more preferable that the difference between the content ratio in the image forming layer B and the content ratio in the image forming layer A 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 B preferably contains the same hot-melt material as the image forming layer A. In the present invention, the content ratio of the heat-meltable substance to the hydrophilic binder in the image forming layer B (mass of the heat-meltable substance / mass of the hydrophilic binder) has a preferable range, and may be 1.0 or more. preferable. In the present invention, the content ratio of the heat-meltable substance with respect to the hydrophilic binder in the image forming layer B is preferably higher than the content ratio in the image forming layer A, and the difference in the ratio is 0.7 or more. It is more preferable that By adjusting to such a range, a heat-sensitive lithographic printing plate excellent in printing durability and stain resistance can be obtained.

  In the image forming layer B of the present invention, as with the image forming layer A, a developer 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. Or a color former (electron-donating dye precursor). Further, preservatives, surfactants, antifoaming agents, leveling agents, pH adjusting agents, other coating aids, and the like can be added as necessary.

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. Further, as a method of coating the image forming layer A and the image forming layer B in the present invention, the image forming layer B on the side close to the support is applied, and then the image forming layer A is sequentially applied and stacked. There are a method and a method of simultaneously applying multiple layers by a slide hopper method, and either method may be used.

<Undercoat layer>
In the heat-sensitive lithographic printing plate of the present invention, an undercoat layer comprising titanium dioxide, a binder resin, and a crosslinking agent is preferably provided between the support and the image forming layer. As a result, there is no change in the plate pressure due to contamination due to plate pressure changes during printing, specifically, slight undulations on the blanket roller of the printing press, without degrading image quality and printing durability. It is possible to improve the printing stain that occurs and develops at the extreme tip and bottom edge of the printing paper surface.

  The titanium dioxide contained in the undercoat layer may be either a rutile type or an anatase type, and the production method is not limited to either the sulfuric acid method or the chlorine method. You may use them individually or in mixture. Furthermore, from the viewpoint of dispersion stability and other functionality, it is possible to selectively use those subjected to various surface treatments. As the surface treatment composition, alumina, silica, zinc oxide, zirconia and the like are common. Examples of commercially available titanium dioxide include SR-1, R-650, R-5N, R-7E, R-3L, A-110, and A-190 from Sakai Chemical Industry Co., Ltd. ) From Taipei R-580, R-930, A-100, A-220, CR-58, Titanium Industry Co., Ltd., Kronos KR-310, KR-380, KA-10, KA -20, Teica Co., Ltd., and Titanics JR-301, JR-600A, JR-800, and JR-701, DuPont Co., Ltd., Taipure R-900, and R-931.

The average particle diameter of titanium dioxide used for the undercoat layer is preferably smaller than the average dry film thickness of the undercoat layer. In general, titanium dioxide is present in the form of secondary particles, tertiary particles, etc., in which some primary particles are aggregated. The average particle size of the titanium dioxide is, for example, titanium dioxide in a dispersion medium to which a dispersant such as polycarboxylic acid, fatty acid amine, sulfonic acid amide, ε-caprolactone, hydrostearic acid, polyesteramine is added. Is dispersed using a media mill such as a ball mill, a bead mill, or a sand grinder, a pressure disperser such as a high pressure homogenizer or an ultra high pressure homogenizer, an ultrasonic disperser, and a thin film swirl disperser. It is preferable to adjust appropriately. A preferable average particle size used in the titanium dioxide layer is preferably 0.1 to 1.5 μm, particularly preferably 0.2 to 1.0 μm. The average particle diameter in the present invention can be measured as a number median diameter using a laser scattering particle size distribution meter (for example, LA920 manufactured by Horiba, Ltd.). On the other hand, the dry solid content of the undercoat layer is preferably in the range of 0.5 to 20 g / m ² .

  The content of titanium dioxide used in the undercoat layer can be set in a wide range, but it is preferably used at 200 to 1000% by mass with respect to 100 parts by mass of the binder resin solid content contained in the undercoat layer. More preferably, it is 400-600 mass%. When the content of titanium dioxide is low, the concealing property may be reduced. When used in excess, the stability of the coating liquid may be reduced or the bulk density may increase due to irregular aggregation. As a result, the surface roughness may increase and the image quality may deteriorate.

  As the binder resin contained in the undercoat layer, for example, gelatin such as lime-processed gelatin, acid-processed gelatin, and enzyme-processed gelatin, water-soluble polymers such as polysaccharides, polyvinyl alcohol, and polyvinylpyrrolidone can be used. It is preferable to use it.

  As the crosslinking agent contained in the undercoat layer, for example, melamine resin, epoxy resin, polyisocyanate compound, aldehyde compound, silane compound, chromium alum, divinyl sulfone, and the like can be preferably used. Is preferred. The blending amount of the crosslinking agent is preferably 1 to 30% by mass, more preferably 2 to 15% by mass, based on the solid content of the binder.

<Support>
A water-resistant support is used as the support used in the heat-sensitive lithographic printing plate of the present invention, but 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. The heat-sensitive lithographic printing plate of the present invention can be suitably used when making a plate using a thermal head. As such an apparatus, 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 this invention is demonstrated using an Example, this invention is not limited by this description. In the following description, “%” and “part” are based on mass unless otherwise specified.

Example 1
On one side of a polyethylene resin-coated paper having a thickness of about 180 μm that has been laminated on both sides, an undercoat layer coating solution of the following composition, an image forming layer B coating solution, and an image forming layer A coating solution a By the slide hopper coating method, three layers were simultaneously applied from the support side so that the undercoat layer, the coating solution for the image forming layer B, and the coating solution a for the image forming layer A (uppermost layer) were arranged in this order. At that time, the wet coating weight, the undercoat layer coating solution 17 g / ^{m 2,} the image forming layer B coating solution 33 g / ^{m 2,} the image forming layer A coating liquid performed by setting the 12 g / ^{m 2} It was.

<Preparation of titanium dioxide slurry>
Titanium dioxide (SR-1, manufactured by Sakai Chemical Industry Co., Ltd., rutile type, alumina treatment) 4.0 parts Acrylic acid copolymerized metal salt 10% aqueous solution 0.2 parts Water to make 11 parts in total, using a homomixer A high-speed fine dispersion treatment for 30 minutes was performed.

<Undercoat layer coating solution>
Gelatin (cow bone, alkali treatment) 0.82 parts Titanium dioxide slurry 11.0 parts Dioctyl sodium sulfosuccinate 5% aqueous solution 0.06 parts Divinyl sulfone 5% aqueous solution 2.0 parts The total amount was made 17 parts with water. A part of the undercoat layer coating solution was sampled, diluted, and the average particle diameter of titanium dioxide was measured using a laser scattering type particle size distribution meter (LA920 manufactured by Horiba, Ltd.). there were.

<Preparation of developer mixed slurry>
As the developer mixed slurry, one prepared in advance by the following preparation method was used.
Material a: 1,2-bis (3-methylphenoxy) ethane
(KS-232 manufactured by Sanko Co., Ltd.)
Material b: 4-hydroxy-4'-isopropoxydiphenyl sulfone
(Nihon Soda Co., Ltd. D-8)
Material c: Anionic styrenic resin 15% aqueous solution
(Polymarlon 1318 manufactured by Arakawa Chemical Industries, Ltd.)

  After mixing 1 part each of material a and material b in water with 0.7 parts of the above material c added under constant stirring, the average particle diameter is reduced using zirconia beads in a small dyno mill (bead mill). A fine dispersion treatment was performed until the particle size became 0.6 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 about 35%.

<Coating solution for image forming layer B>
Gelatin (cow bone, alkali treated) 0.78 parts Polyvinyl alcohol (PVA-505 manufactured by Kuraray Co., Ltd.) 0.07 parts Latex of carboxyl-modified styrene-butadiene copolymer 2.8 parts (Rack manufactured by DIC Corporation) Star 7132C, 45% slurry, Tg = 60 ° C.)
Developer mixed slurry 8.4 parts 3-dibutylamino-6-methyl-7-anilinofluorane 30% slurry
0.7 parts Surfactant 5% aqueous solution 0.4 parts (Perox OTP (sodium dialkylsulfosuccinate) manufactured by Kao Corporation)
Divinylsulfone 5% aqueous solution 2.0 parts The total amount was 33 parts with water.

<Preparation of barium sulfate slurry>
1.0 parts of barium sulfate (B-35 manufactured by Sakai Chemical Industry Co., Ltd., average particle size = 0.3 μm)
Acrylic acid copolymerized metal salt 10% aqueous solution 0.7 part The total amount was 10 parts with water, and high-speed fine dispersion treatment was performed for 30 minutes using a homomixer.

<Coating fluid a for image forming layer A>
Gelatin (cow bone, alkali-treated) 0.29 part Pullulan (Pullulan manufactured by Hayashibara Corporation) 0.02 part Latex of carboxyl-modified styrene-butadiene copolymer 0.6 part (Lackster 7132C manufactured by DIC Corporation) 45% slurry, Tg = 60 ° C.)
3-dibutylamino-6-methyl-7-anilinofluorane 30% slurry
0.3 part Surfactant 5% aqueous solution 0.2 part (Perox OTP (sodium dialkylsulfosuccinate) manufactured by Kao Corporation)
Montanic acid ester wax 30% slurry 0.5 parts (Hydrin J-537 manufactured by Chukyo Yushi Co., Ltd.)
Barium sulfate slurry 1.0 part 10% aqueous solution of surfactant having a perfluoroalkyl group 0.03 part (Surflon S-386 manufactured by AGC Seimi Chemical Co., Ltd.)
Divinyl sulfone 5% aqueous solution 0.7 part The total amount was 12 parts with water.

  After three layers were simultaneously applied at the moisture application amount, the coating film was immediately gelled with cold air of 1 to 3 ° C., and then dried with hot air set at 30 ° C. After drying, a thermosensitive lithographic printing plate of Example 1 was obtained by heating for 7 days using a constant temperature and humidity chamber adjusted to a temperature of 40 ° C./humidity of 40%.

The thermal lithographic printing plate produced as described above was subjected to image output (recording energy density 70 to 100 mJ / mm ² ) using a thermal digital printer for CTP (Thermal Digiplater TDP-459: 1200 dpi / 120 lpi manufactured by Mitsubishi Paper Industries). The electric capacity was 330 W), and a printing plate was prepared.

<Image unevenness>
99 strips of 10 vertical stripes with 10mm width x 400mm long strip-shaped solid images arranged at intervals of 20mm in the width direction are engraved, and the 100th plate has only halftone dots with a dot area ratio of 40%. Was made. Thereafter, the thermal head is rubbed with 3 sets of lapping sheet film (A3-3SHT, manufactured by Sumitomo 3M Co., Ltd., mesh number # 4000, grain size 3 μm) as 10 sets of 1 round trip, and the dot area ratio is 40 for each set. A plate with only halftone dots was made. The 100th printing plate, the printing plate after rubbing 1 set, the printing plate after rubbing 2 sets, and the printing plate after rubbing 3 sets were visually judged using the following criteria. The results are shown in Table 1.
A: Image unevenness is observed in the 100th printing plate with respect to the conveying direction of the printing plate, but the image unevenness is not observed in the printing plate after rubbing one set.
○: Image unevenness is observed in the 100th printing plate and printing plate after one set rubbing with respect to the conveying direction of the printing plate, but no image unevenness is observed in the printing plate after two sets rubbing.
Δ: Image unevenness is observed in the printing plate of the 100th plate and the printing plate after rubbing 1-2 sets, but the image unevenness is observed in the printing plate after rubbing 3 sets. Absent.
X: Image unevenness is observed in the 100th printing plate and the printing plate after rubbing 1-3 sets with respect to the conveying direction of the printing plate.

<Print durability>
As for printing durability, an image for printing evaluation was made under the above-mentioned plate making conditions, and a printing test was conducted using this as a printing sample. The printing machine uses HAMADA H234C (offset printing machine manufactured by Hamada Printing Machinery Co., Ltd.), the printing ink is ECO Diamond Excel (Mitsubishi Paper Co., Ltd.), and the dampening liquid is TDP-DL1 (Mitsubishi Paper Co., Ltd.). ) Moisturizing liquid) A 10% aqueous solution was used, and printing was started after wiping the plate surface with a 25% aqueous solution of TDP-HL (an etching liquid manufactured by Mitsubishi Paper Industries Co., Ltd.) all over the printing plate. For printing durability evaluation, the printing paper surface at the start and the printing paper surface at the time of printing 5,000 sheets were compared, and the attenuation ratio of 20% halftone dot and 50% halftone dot was observed with a 25 times loupe. The evaluation criteria were used. The results are shown in Table 1.
A: Almost no change in both 20% and 50% halftone dots.
○: Almost no change at 50% halftone dot, but attenuation can be confirmed at 20% halftone dot.
Δ: Attenuation can be confirmed for both 20% and 50% halftone dots.
X: Attenuation of 50% or more is observed at the 20% halftone dot portion.

<Soil resistance>
With respect to the soil resistance, a printing evaluation image was made under the above-mentioned plate making conditions, and a printing test was conducted using this as a printing sample. RYOBI3200CCD (offset printing machine manufactured by Ryobi Co., Ltd.) was used as the printing machine, printing ink was New Champion F gloss ink S manufactured by DIC Corporation, and TDP-DL1 (manufactured by Mitsubishi Paper Industries) was used as the dampening solution. Printing was started after using a 5% aqueous solution and wiping the plate surface with a 10% aqueous solution of TDP-HL (Mitsubishi Paper Co., Ltd. etching solution) before starting printing. As the evaluation of the background stain resistance, blanket stains that cause background stains were compared using the following criteria by comparing the start of printing with that after 3,000 sheets were printed. The results are shown in Table 1.
(Double-circle): There is no blanket dirt.
○: The blanket is slightly dirty.
X: The blanket is dirty.

(Example 2)
In the production method of the thermosensitive lithographic printing plate of Example 1, Example 1 was carried out in the same manner as Example 1 except that the coating liquid b of the image forming layer A was used instead of the coating liquid a of the image forming layer A. No. 2 thermal lithographic printing plate was obtained. The obtained heat-sensitive lithographic printing plate was evaluated in the same manner as the heat-sensitive lithographic printing plate of Example 1. The results are shown in Table 1.

<Coating liquid b for image forming layer A>
Gelatin (cow bone, alkali-treated) 0.29 part Pullulan (Pullulan manufactured by Hayashibara Corporation) 0.02 part Latex of carboxyl-modified styrene-butadiene copolymer 0.6 part (Lackster 7132C manufactured by DIC Corporation) 45% slurry, Tg = 60 ° C.)
3-dibutylamino-6-methyl-7-anilinofluorane 30% slurry
0.3 part Surfactant 5% aqueous solution 0.2 part (Perox OTP (sodium dialkylsulfosuccinate) manufactured by Kao Corporation)
Montanic acid ester wax 30% slurry 0.5 parts (Hydrin J-537 manufactured by Chukyo Yushi Co., Ltd.)
Barium sulfate slurry 1.0 part Perfluoroalkyl group-containing surfactant 10% aqueous solution 0.021 part (AGC Seimi Chemical Co., Ltd. Surflon S-386)
Divinyl sulfone 5% aqueous solution 0.7 part The total amount was 12 parts with water.

(Example 3)
In the production method of the thermosensitive lithographic printing plate of Example 1, Example 1 was carried out in the same manner as Example 1 except that the coating liquid c of the image forming layer A was used instead of the coating liquid a of the image forming layer A. No. 3 thermal lithographic printing plate was obtained. The obtained heat-sensitive lithographic printing plate was evaluated in the same manner as the heat-sensitive lithographic printing plate of Example 1. The results are shown in Table 1.

<Coating liquid c for image forming layer A>
Gelatin (cow bone, alkali-treated) 0.29 part Pullulan (Pullulan manufactured by Hayashibara Corporation) 0.02 part Latex of carboxyl-modified styrene-butadiene copolymer 0.6 part (Lackster 7132C manufactured by DIC Corporation) 45% slurry, Tg = 60 ° C.)
3-dibutylamino-6-methyl-7-anilinofluorane 30% slurry
0.3 part Surfactant 5% aqueous solution 0.2 part (Perox OTP (sodium dialkylsulfosuccinate) manufactured by Kao Corporation)
Montanic acid ester wax 30% slurry 0.5 parts (Hydrin J-537 manufactured by Chukyo Yushi Co., Ltd.)
Barium sulfate slurry 1.0 part Surfactant 10% aqueous solution having a perfluoroalkyl group 0.085 part (AGC Seimi Chemical Co., Ltd. Surflon S-386)
Divinyl sulfone 5% aqueous solution 0.7 part The total amount was 12 parts with water.

Example 4
In the manufacturing method of the thermosensitive lithographic printing plate of Example 1, Example 1 was carried out in the same manner as Example 1 except that the coating liquid d of the image forming layer A was used instead of the coating liquid a of the image forming layer A. No. 4 thermal lithographic printing plate was obtained. The obtained heat-sensitive lithographic printing plate was evaluated in the same manner as the heat-sensitive lithographic printing plate of Example 1. The results are shown in Table 1.

<Coating liquid d for image forming layer A>
Gelatin (cow bone, alkali-treated) 0.29 part Pullulan (Pullulan manufactured by Hayashibara Corporation) 0.02 part Latex of carboxyl-modified styrene-butadiene copolymer 0.6 part (Lackster 7132C manufactured by DIC Corporation) 45% slurry, Tg = 60 ° C.)
3-dibutylamino-6-methyl-7-anilinofluorane 30% slurry
0.3 part Surfactant 5% aqueous solution 0.2 part (Perox OTP (sodium dialkylsulfosuccinate) manufactured by Kao Corporation)
Montanic acid ester wax 30% slurry 0.5 parts (Hydrin J-537 manufactured by Chukyo Yushi Co., Ltd.)
Barium sulfate slurry 1.0 part 0.012 part of surfactant 10% aqueous solution having a perfluoroalkyl group (Surflon S-386 manufactured by AGC Seimi Chemical Co., Ltd.)
Divinyl sulfone 5% aqueous solution 0.7 part The total amount was 12 parts with water.

(Example 5)
In the method for producing a heat-sensitive lithographic printing plate of Example 1, the same procedure as in Example 1 was conducted except that the coating liquid e for the image forming layer A was used instead of the coating liquid a for the image forming layer A. No. 5 thermal lithographic printing plate was obtained. The obtained heat-sensitive lithographic printing plate was evaluated in the same manner as the heat-sensitive lithographic printing plate of Example 1. The results are shown in Table 1.

<Coating fluid e for image forming layer A>
Gelatin (cow bone, alkali-treated) 0.29 part Pullulan (Pullulan manufactured by Hayashibara Corporation) 0.02 part Latex of carboxyl-modified styrene-butadiene copolymer 0.6 part (Lackster 7132C manufactured by DIC Corporation) 45% slurry, Tg = 60 ° C.)
3-dibutylamino-6-methyl-7-anilinofluorane 30% slurry
0.3 part Surfactant 5% aqueous solution 0.2 part (Perox OTP (sodium dialkylsulfosuccinate) manufactured by Kao Corporation)
Montanic acid ester wax 30% slurry 0.5 parts (Hydrin J-537 manufactured by Chukyo Yushi Co., Ltd.)
Barium sulfate slurry 1.0 part 0.12 part of 10% surfactant aqueous solution having a perfluoroalkyl group (Surflon S-386 manufactured by AGC Seimi Chemical Co., Ltd.)
Divinyl sulfone 5% aqueous solution 0.7 part The total amount was 12 parts with water.

(Comparative Example 1)
In the method for producing a heat-sensitive lithographic printing plate of Example 1, a comparative example was carried out in the same manner as in Example 1 except that the coating liquid f of the image forming layer A was used instead of the coating liquid a of the image forming layer A. 1 thermal lithographic printing plate was obtained. The obtained heat-sensitive lithographic printing plate was evaluated in the same manner as the heat-sensitive lithographic printing plate of Example 1. The results are shown in Table 1.

<Coating fluid f for image forming layer A>
Gelatin (cow bone, alkali-treated) 0.29 part Pullulan (Pullulan manufactured by Hayashibara Corporation) 0.02 part Latex of carboxyl-modified styrene-butadiene copolymer 0.6 part (Lackster 7132C manufactured by DIC Corporation) 45% slurry, Tg = 60 ° C.)
3-dibutylamino-6-methyl-7-anilinofluorane 30% slurry
0.3 part Surfactant 5% aqueous solution 0.2 part (Perox OTP (sodium dialkylsulfosuccinate) manufactured by Kao Corporation)
Montanic acid ester wax 30% slurry 0.5 parts (Hydrin J-537 manufactured by Chukyo Yushi Co., Ltd.)
Barium sulfate slurry 1.0 part Divinyl sulfone 5% aqueous solution 0.7 part The total amount was 12 parts with water.

(Comparative Example 2)
In the method for producing a heat-sensitive lithographic printing plate of Example 1, a comparative example was carried out in the same manner as in Example 1 except that the coating liquid g for the image forming layer A was used instead of the coating liquid a for the image forming layer A. No. 2 thermal lithographic printing plate was obtained. The obtained heat-sensitive lithographic printing plate was evaluated in the same manner as the heat-sensitive lithographic printing plate of Example 1. The results are shown in Table 1.

<Coating liquid g for image forming layer A>
Gelatin (cow bone, alkali-treated) 0.29 part Pullulan (Pullulan manufactured by Hayashibara Corporation) 0.02 part Latex of carboxyl-modified styrene-butadiene copolymer 0.6 part (Lackster 7132C manufactured by DIC Corporation) 45% slurry, Tg = 60 ° C.)
3-dibutylamino-6-methyl-7-anilinofluorane 30% slurry
0.3 parts Surfactant 5% aqueous solution 0.4 parts (Perox OTP (sodium dialkylsulfosuccinate) manufactured by Kao Corporation)
Montanic acid ester wax 30% slurry 0.5 parts (Hydrin J-537 manufactured by Chukyo Yushi Co., Ltd.)
Barium sulfate slurry 1.0 part Divinyl sulfone 5% aqueous solution 0.7 part The total amount was 12 parts with water.

(Comparative Example 3)
In the method for producing the heat-sensitive lithographic printing plate of Example 1, a comparative example was carried out in the same manner as in Example 1 except that the coating liquid h of the image forming layer A was used instead of the coating liquid a of the image forming layer A. No. 3 thermal lithographic printing plate was obtained. The obtained heat-sensitive lithographic printing plate was evaluated in the same manner as the heat-sensitive lithographic printing plate of Example 1. The results are shown in Table 1.

<Coating liquid h for image forming layer A>
Gelatin (cow bone, alkali-treated) 0.29 part Pullulan (Pullulan manufactured by Hayashibara Corporation) 0.02 part Latex of carboxyl-modified styrene-butadiene copolymer 0.6 part (Lackster 7132C manufactured by DIC Corporation) 45% slurry, Tg = 60 ° C.)
3-dibutylamino-6-methyl-7-anilinofluorane 30% slurry
0.3 part Surfactant 5% aqueous solution 0.2 part (Perox OTP (sodium dialkylsulfosuccinate) manufactured by Kao Corporation)
Montanic acid ester wax 30% slurry 0.5 parts (Hydrin J-537 manufactured by Chukyo Yushi Co., Ltd.)
Barium sulfate slurry 1.0 part Surfactant 10% solution 0.1 part (Nikko Chemicals Co., Ltd. NIKKOL BT-9 (polyoxyethylene alkyl ether))
Divinyl sulfone 5% aqueous solution 0.7 part The total amount was 12 parts with water.

(Example 6)
In the method for producing a heat-sensitive lithographic printing plate of Example 1, a 10% aqueous surfactant solution having a perfluoroalkyl group in the coating solution a of the image forming layer A (Surflon S-386 manufactured by AGC Seimi Chemical Co., Ltd.), Example 3 was carried out in the same manner as in Example 1 except that 0.03 part was changed to a surfactant 10% aqueous solution having a perfluoroalkyl group (Surflon S-242 manufactured by AGC Seimi Chemical Co., Ltd.) and 0.03 part. A heat-sensitive lithographic printing plate of Example 6 was obtained. The obtained heat-sensitive lithographic printing plate was evaluated in the same manner as the heat-sensitive lithographic printing plate of Example 1. The results are shown in Table 1.

(Example 7)
In the method for producing a heat-sensitive lithographic printing plate of Example 1, the same as Example 1 except that 1.0 part of the barium sulfate slurry in the coating solution a of the image forming layer A was changed to 1.0 part of the zinc oxide slurry. Thus, a heat-sensitive lithographic printing plate of Example 7 was obtained. The obtained heat-sensitive lithographic printing plate was evaluated in the same manner as the heat-sensitive lithographic printing plate of Example 1. The results are shown in Table 1.

<Preparation of zinc oxide slurry>
Zinc oxide 1.0 part (manufactured by Sakai Chemical Industry Co., Ltd., fine zinc oxide, average particle size = 0.29 μm)
Acrylic acid copolymerized metal salt 10% aqueous solution 0.7 part The total amount was 10 parts with water, and high-speed fine dispersion treatment was performed for 30 minutes using a homomixer.

  As can be seen from the results shown in Table 1, the present invention is a heat-sensitive lithographic plate which has excellent printing durability and background stain resistance, and has improved image unevenness caused by head residue when a thermal head is used for a long time. It can be seen that a printing plate is obtained.

Claims (1)

  Surface-active having at least two image-forming layers containing a thermoplastic resin and a hydrophilic binder on the support, and the image-forming layer far from the support having zinc oxide or barium sulfate and a perfluoroalkyl group A heat-sensitive lithographic printing plate comprising an agent.