JP2006199019A - Original plate for lithographic printing, hydrophilic substrate and lithographic printing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an original plate for lithographic printing which enables printing without development after exposure and which excels in plate wear properties, hardly brings about scumming and excels also in removal of ink. <P>SOLUTION: The original plate for lithographic printing comprises a hydrophilic image recording layer containing a hydrophilic polymer and a hydrophilicity-hydrophobicity conversion agent acting by being given heat energy and of a substrate. Herein the hydrophilic polymer containing a hydrophilic chain constituted of a main chain and a branched chain which has a mass average molecular weight of 200-100 millions, is used. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a lithographic printing plate precursor having a hydrophilic layer containing a hydrophilic polymer and a hydrophilic-hydrophobic conversion agent that acts by application of thermal energy, and a support. The present invention also relates to a hydrophilic substrate comprising a hydrophilic image recording layer containing a hydrophilic polymer and a support. Furthermore, the present invention also relates to a lithographic printing method that employs no processing or on-press development processing.

  Numerous studies have been made on computer-to-plate printing plates that have made significant progress in recent years. In order to streamline the processing process and solve the waste liquid treatment problem, a lithographic printing plate that can be mounted and printed on a printing machine as it is without development processing after exposure, or a lithographic plate that can be exposed on a printing machine and printed as it is Printing masters have been studied and various methods have been proposed.

A heat-sensitive lithographic printing original plate having a hydrophilic image-recording layer in which thermoplastic polymer fine particles are dispersed in a matrix (eg, hydrophilic resin) on a substrate having a hydrophilic surface has been proposed (for example, a patent References 1-3). When heat is applied to the image recording layer by photothermal conversion of infrared rays, the thermoplastic polymer fine particles are melted and the surface of the hydrophilic image recording layer is converted into a hydrophobic image portion. The lithographic printing plate on which the image portion is formed is mounted on a printing machine, and the unheated portion is removed by supplying dampening water and ink to the printing plate while rotating the plate cylinder. By this on-machine development processing, the conventional development processing using an automatic developing machine can be omitted.
Further, it has been proposed to develop an on-press development of a lithographic printing material containing a microgel having a group capable of decomposing by light or heat energy on the surface and an infrared light absorber in an image recording layer (for example, Patent Document 4). reference).

  However, in the conventional on-press development type unprocessed lithographic printing plate, the removal of the unexposed area depends on the operation start conditions of the printing machine, or the removal product containing a large amount of lipophilic component is dampened with a dampening water roller or dampening machine. In order to obtain a good printed matter, it is necessary to print several tens to several hundreds of sheets, and it is necessary to clean the rollers.

  A heat-sensitive lithographic printing original plate having a heat-sensitive layer dispersed in a hydrophilic resin in which thermoplastic polymer fine particles are crosslinked has been proposed (see, for example, Non-Patent Document 1). In addition, a heat-sensitive lithographic printing original plate having a hydrophilic layer in which microcapsules encapsulating lipophilic components as lipophilic fine particles in a cross-linked hydrophilic binder polymer is also proposed (see, for example, Patent Documents 5 to 8). ). These heat-sensitive lithographic printing original plates do not require on-machine development by using the surface structure of the oleophilic image area formed by heat from exposure and the hydrophilic non-image area of the unexposed area as the printing surface. Lithographic printing using fountain solution can be performed without any treatment.

However, the hydrophilicity and durability of the hydrophilic layer provided on the substrate are insufficient, and there is a problem that ground stains (dirt of non-image areas) gradually occur depending on printing conditions.
As a conventional hydrophilic layer, a hydrophilic layer obtained by curing an acrylamide-hydroxyethyl acrylate copolymer with a methylol melamine crosslinking agent (for example, see Patent Document 9), a hydrophilic layer using gelatin or polyvinyl alcohol (for example, a patent) Reference 10), a hydrophilic image recording layer containing a hydrophilic heat-sensitive polymer containing a repeating unit containing a quaternary ammonium carboxylate group (for example, see Patent Document 11) has been proposed. All of the hydrophilic layers lacked hydrophilicity and water retention, and had problems with ink removal during printing and stains on non-image areas.

Japanese Patent No. 2938397 JP-A-9-127683 WO99 / 10186 pamphlet JP 2000-238452 A JP-A-7-1849 JP-A-7-1850 Japanese Patent Laid-Open No. 10-6468 Japanese Patent Laid-Open No. 11-70756 JP 2002-370467 A JP-A-11-95417 Special table 2003-527978 description Research Disclosure, January 1992, No. 33303

An object of the present invention is to provide a lithographic printing original plate that can be printed without being subjected to development processing after exposure, has excellent printing durability, hardly causes scumming, and has excellent ink removal. is there.
Another object of the present invention is to provide a hydrophilic substrate having excellent printing durability and water retention.

The present invention provides the following lithographic printing original plates (1) to (9), the hydrophilic substrate (10) below and the lithographic printing methods (11) to (13) below.
(1) A lithographic printing original plate comprising a hydrophilic image recording layer containing a hydrophilic polymer and a hydrophilic-hydrophobic conversion agent acting by applying thermal energy, and a support, wherein the hydrophilic polymer comprises a main chain and a branched chain. A lithographic printing plate precursor comprising: a branched chain comprising a hydrophilic chain having a mass average molecular weight of 2 to 1,000,000.

(2) The lithographic printing plate precursor as described in (1), wherein the branched chain comprises a hydrophilic chain and a linking group, and the linking group is interposed between the hydrophilic chain and the main chain.
(3) The lithographic printing plate precursor as described in (2), wherein the linking group contains an ionic bond.
(4) The lithographic printing plate precursor as described in (1), wherein the main chain is composed of two or more types of repeating units.
(5) The lithographic printing plate precursor according to (4), wherein a branched chain is bonded to one type of repeating unit of the main chain, and no branched chain is bonded to the other type of repeating unit of the main chain.

(6) The branched chain is composed of a hydrophilic chain and a linking group, the linking group is interposed between the hydrophilic chain and the main chain, and the same molecular structure as the other types of repeating units in the main chain and the linking group. The lithographic printing plate precursor as described in (5) having
(7) The lithographic printing plate precursor as described in (1), wherein the main chain has a mass average molecular weight of 1,000 to 2,000,000.
(8) The lithographic printing plate precursor as described in (1), wherein the main chain has a crosslinked structure.
(9) The lithographic printing plate precursor as described in (8), wherein the crosslinked structure contains an ionic bond.

(10) A hydrophilic substrate comprising a hydrophilic layer containing a hydrophilic polymer and a support, wherein the hydrophilic polymer comprises a main chain and a branched chain, and the branched chain has a mass average molecular weight of 2 to 1,000,000. A hydrophilic substrate comprising a chain.
(11) A hydrophilic image-recording layer containing a hydrophilic-hydrophobic conversion agent and a hydrophilic polymer acting by applying thermal energy and a support, the hydrophilic polymer comprising a main chain and a branched chain, and the branched chain being 200 A lithographic printing original plate containing a hydrophilic chain having a mass average molecular weight of 1 to 1,000,000 is heated corresponding to the image, and a part of the hydrophilic image recording layer is converted into a hydrophobic region, and a hydrophilic region is formed on the surface. A lithographic printing method comprising a step of making a lithographic printing plate having a hydrophobic region; and a step of supplying fountain solution and oil-based ink to the lithographic printing plate for printing.

(12) A hydrophilic substrate comprising a hydrophilic layer containing a hydrophilic polymer and a support, the hydrophilic polymer comprising a main chain and a branched chain, and the branched chain comprising a hydrophilic chain having a mass average molecular weight of 2 to 1,000,000 A part of the hydrophobic image recording layer is removed corresponding to the image from the lithographic printing original plate comprising the hydrophobic image recording layer provided on the hydrophilic layer, and a hydrophilic region comprising the exposed hydrophilic layer; A lithographic printing method comprising a step of making a lithographic printing plate having a hydrophobic region comprising a remaining hydrophobic image recording layer; and a step of supplying a lithographic printing plate with dampening water and oil-based ink for printing.
(13) A hydrophilic substrate comprising a hydrophilic layer containing a hydrophilic polymer and a support, the hydrophilic polymer comprising a main chain and a branched chain, and the branched chain comprising a hydrophilic chain having a mass average molecular weight of 2 to 1,000,000 And a step of making a lithographic printing plate having a hydrophilic region consisting of the surface of the hydrophilic layer and a hydrophobic region to which the hydrophobic material is attached; A lithographic printing method comprising a step of printing with a fountain solution and oil-based ink supplied to a plate.

As a result of the present inventors' study, a hydrophilic polymer comprising a hydrophilic chain comprising a main chain and a branched chain and having a weight average molecular weight of 200 to 1,000,000 (preferably 1,000 to 1,000,000) is very hydrophilic. The hydrophilic layer containing this hydrophilic polymer was found to have excellent strength (printing durability). The hydrophilic polymer can have a three-dimensional polymer molecular structure with high density and excellent strength. Such a hydrophilic polymer can be obtained by reacting a hydrophilic (raw material) polymer having a reactive group at one end with a chemical binder. As a result of the chemical reaction, one end of the hydrophilic chain is fixed by a chemical bond in the three-dimensional molecular structure of the hydrophilic polymer. When a plurality of chemical binders are used in the reaction, the density and strength of the hydrophilic polymer are further improved.
In the three-dimensional molecular structure of the hydrophilic polymer, since only one end of the hydrophilic chain is fixed and the other end is not fixed, the structure has a high degree of freedom and excellent mobility.

For the above reasons, the lithographic printing plate made from the lithographic printing original plate according to the present invention can efficiently supply and discharge dampening water during printing. Furthermore, since a large amount of hydrophilic chains can be introduced into the branched chain in the three-dimensional molecular structure of the hydrophilic polymer, a large amount of dampening water can be retained as required. When a highly hydrophilic layer capable of retaining a large amount of dampening water is used, background stains are less likely to occur and ink repellency is improved.
In a lithographic printing original plate not subjected to conventional development processing (completely unprocessed), a polymer obtained by crosslinking a part of hydrophilic groups of a hydrophilic polymer with a crosslinking agent is generally used for the hydrophilic layer. Conventional polymers have a low degree of freedom in the hydrophilic portion and a low water retention function.

  As described above, the hydrophilic layer excellent in printing durability and water retention is used as an image recording layer containing a hydrophilic-hydrophobic conversion agent that acts by application of thermal energy. It can also be advantageously used as a hydrophilic layer in a hydrophilic substrate comprising a support. For example, even if a hydrophobic image recording layer (a layer that can be removed corresponding to an image) is provided on a hydrophilic substrate, or a hydrophobic image is directly formed, lithographic printing having a good hydrophilic region You can get a version.

[Hydrophilic polymer]
The hydrophilic polymer consists of a main chain and a branched chain. The branched chain binds to the main chain only at one end of the chain structure. The hydrophilic polymer preferably has 3 or more branched chains, more preferably 5 or more branched chains, and most preferably 10 or more branched chains.
The branched chain includes a hydrophilic chain having a mass average molecular weight of 2 to 1 million.
The branched chain is preferably composed of a hydrophilic chain and a linking group, and the linking group is preferably interposed between the hydrophilic chain and the main chain. The linking group can include an ionic bond. When the linking group includes an ionic bond, the hydrophilicity of the hydrophilic polymer can be further improved.
The content of the branched chain is preferably 10 to 95% by mass, more preferably 20 to 90% by mass, and most preferably 30 to 80% by mass with respect to the total amount of the hydrophilic layer.

The main chain means a backbone from which the branched chain branches, and the main chain may be shorter than the branched chain (or hydrophilic chain). The main chain may be a low molecular weight oligomer. The main chain may be a polymer having a mass average molecular weight of 1,000 to 2,000,000, or a polymer having a crosslinked structure.
The main chain is preferably composed of two or more kinds of repeating units. More preferably, a branched chain is bonded to one type of repeating unit of the main chain, and no branched chain is bonded to another type of repeating unit of the main chain.
When the branched chain is composed of a hydrophilic chain and a linking group, other types of repeating units of the main chain and the linking group can have the same molecular structure. When the main chain has a cross-linked structure, the other types of repeating units of the main chain and the cross-linked structure may have the same molecular structure.
The cross-linked structure can include ionic bonds. When the crosslinked structure includes an ionic bond, the hydrophilicity of the hydrophilic polymer can be further improved.

(Hydrophilic chain)
The hydrophilic chain can be formed by introducing a reactive group only at one end (one end) of the hydrophilic raw material polymer.
Hydrophilic raw material polymers include natural polymers (eg, polysaccharides, proteins), semi-synthetic polymers (eg, starch derivatives, cellulose ethers, cellulose esters) and synthetic polymers.
The main chain of the hydrophilic chain (not the main chain of the hydrophilic polymer) is preferably hydrocarbon, halogenated hydrocarbon, polyester, polyamide, polyamine, polyether, polyurethane, polyurea or a combination thereof, and hydrocarbon, polyether More preferred are polyurethanes, polyureas or combinations thereof, most preferred are hydrocarbons. Some carbon atoms of the hydrocarbon main chain may be replaced with hetero atoms (eg, oxygen atom, nitrogen atom, sulfur atom, phosphorus atom).

The hydrophilic chain preferably has a hydrophilic group as a side chain, a main chain or a side chain substituent. The hydrophilic group is preferably a carboxylic acid group, amino group, phosphoric acid group, sulfonic acid group, hydroxyl, amide group, sulfonamide group, alkoxy group, cyano, polyoxyalkylene group (eg, polyoxyethylene), and carboxylic acid More preferred are a group, an amino group, a sulfonic acid group, a hydroxyl group, an amide group, and a polyoxyalkylene group.
The carboxylic acid group, phosphoric acid group, and sulfonic acid group may be in the form of an anion or salt. The counter cation of the carboxylic acid group is preferably an ammonium ion or an alkali metal ion. The counter cation of the sulfonic acid group is preferably an ammonium ion, an alkali metal ion, or an alkaline earth metal ion.
The amino group may be in the form of a cation (ammonium group) or a salt. The counter anion of the amino group is preferably a halide ion.
It is preferable that at least one hydrophilic group is contained per repeating unit of the hydrophilic chain.

  A linking group may be interposed between the main chain of the hydrophilic chain and the hydrophilic group. The linking group is preferably selected from —O—, —S—, —CO—, —NH—, —N <, an aliphatic group, an aromatic group, a heterocyclic group, and combinations thereof.

  The hydrophilic chain is preferably a polymer of an ethylenically unsaturated monomer having a hydrophilic group. Examples of ethylenically unsaturated monomers having hydrophilic groups are (meth) acrylic acid and its salts, itaconic acid and its salts, maleic acid and its salts, 2-hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate Hydroxybutyl (meth) acrylate, (meth) acrylamide, N-monomethylol (meth) acrylamide, N, N-dimethylol (meth) acrylamide, 3-vinylpropionic acid and its salt, vinylsulfonic acid and its salt, 2- Sulfoethyl (meth) acrylate and salt thereof, polyoxyethylene glycol mono (meth) acrylate, 2-acrylamido-2-methylpropanesulfonic acid and salt thereof, phosphooxypolyoxyethylene glycol mono (meth) acrylate and salt thereof Allylamine, including hydroxypropylene. Polyvinyl alcohol, polyvinyl formal, polyvinyl butyral, and polyvinyl pyrrolidone are also included in the polymer of an ethylenically unsaturated monomer having a hydrophilic group. The saponification degree of polyvinyl alcohol is preferably 60% by mass or more, and more preferably 80% by mass or more.

  The hydrophilic chain may be a homopolymer of an ethylenically unsaturated monomer having a hydrophilic group. The hydrophilic chain may be a copolymer of ethylenically unsaturated monomers having two or more types of hydrophilic groups. The hydrophilic chain may be a copolymer of an ethylenically unsaturated monomer having a hydrophilic group and another ethylenically unsaturated monomer (having no hydrophilic group).

A reactive group is introduced only at one end of the hydrophilic chain. “Reactive group” means a functional group that can react with a main chain or a monomer for forming a main chain to form a chemical bond, and is determined in relation to the main chain or the reactive group of the monomer. Concept. The hydrophilic raw material polymer corresponding to the hydrophilic chain is water-soluble, and preferably becomes water-insoluble when bonded to the main chain.
In this specification, the chemical bond includes a covalent bond, an ionic bond, a coordination bond, and a hydrogen bond in the same manner as in a normal meaning. The chemical bond is preferably a covalent bond.
The reactive group is generally the same as the reactive group contained in the polymer crosslinking agent. The crosslinking agent is described in “Crosslinking agent handbook” by Shinzo Yamashita, Tosuke Kaneko, published by Taiseisha (1981).

Examples of reactive groups are carboxyl (HOOC-), salts thereof (MOOC-, where M is a cation), carboxylic anhydride groups (eg monovalent groups derived from succinic anhydride, phthalic anhydride or maleic anhydride). ), Amino (H ₂ N—), hydroxyl (HO—), epoxy group (eg, 1,2-epoxyethyl), methylol (HO—CH ₂ —), mercapto (HS—), isocyanate (OCN—) , A block isocyanate group, an alkoxysilyl group, an ethylenically unsaturated double bond, an ester bond, and a tetrazole group. Two or more reactive groups may be introduced at one end. Two or more reactive groups may be different from each other.
The reactive group is preferably a functional group different from the hydrophilic group. The reactive group is preferably more reactive than the hydrophilic group. Here, “high reactivity” is a relative concept determined by the relationship with the main chain or the reactive group of the monomer.

  It is preferable that a linking group is interposed between the hydrophilic chain and the reactive group. The linking group is preferably selected from —O—, —S—, —CO—, —NH—, —N <, an aliphatic group, an aromatic group, a heterocyclic group, and combinations thereof. The linking group is preferably -O-, -S-, or a combination containing -O- or -S-, and more preferably bonded to a repeating unit of a hydrophilic chain at -O- or -S-. .

  The hydrophilic chain having a reactive group is preferably represented by the following formula (I).

In the formula (I), Rc is a reactive group. The reactive group is carboxyl, its salt, carboxylic anhydride group, amino, hydroxyl, epoxy group, methylol, mercapto, isocyanate, block isocyanate group, alkoxysilyl group, ethylenically unsaturated double bond, ester bond or tetrazole It is preferably a group.
In the formula (I), L ¹ is a single bond or a divalent linking group. The divalent linking group is preferably selected from —O—, —CO—, —NH—, a divalent aliphatic group, a divalent aromatic group, a divalent heterocyclic group, and combinations thereof. .
In the formula (I), -X- is -O- or -S-. -S- is preferred to -O-.

In the formula (I), R is a hydrogen atom, a halogen atom, or an alkyl group having 1 to 10 carbon atoms. R is preferably a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, more preferably a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and most preferably a hydrogen atom or methyl.
In formula (I), Hy is a hydrophilic group. Hydrophilic groups include carboxylic acid groups and salts thereof, amino groups and salts thereof, phosphoric acid groups and salts thereof, sulfonic acid groups and salts thereof, hydroxyl groups, amide groups, sulfonamido groups, alkoxy groups, cyano and polyoxyethylene groups. Is preferably selected from.
In the formula (I), L ² is a single bond or a divalent linking group. The divalent linking group is preferably selected from —O—, —CO—, —NH—, a divalent aliphatic group, a divalent aromatic group, a divalent heterocyclic group, and combinations thereof. .
Examples of hydrophilic chains having a reactive group at one end are shown below.

  The hydrophilic chain having a reactive group at one end is, for example, a chain transfer agent (described in radical polymerization handbook (NTS, Mikiji Tsunoike, Takeshi Endo)) or Iniferter (Macromolecules 1986, 19, p287- (Otsu)). Can be synthesized by radical polymerization of a hydrophilic monomer (eg, acrylamide, acrylic acid, methacrylic acid 3-sulfopropyl ester potassium salt) in the presence of Examples of chain transfer agents include 3-mercaptopropionic acid, 2-aminoethanethiol hydrochloride, 3-mercaptopropanol, 2-hydroxyethyl disulfide. Alternatively, a hydrophilic monomer (eg, acrylamide) may be radically polymerized using a radical polymerization initiator having a reactive group (eg, carboxyl) without using a chain transfer agent. However, the radical polymerization method using a chain transfer agent is preferable because the molecular weight of the target polymer can be easily controlled.

The mass average molecular weight of the hydrophilic chain having a reactive group at one end is preferably 1,000,000 or less, more preferably 200 to 1,000,000, and most preferably 1,000 to 100,000. When the molecular weight exceeds 1,000,000, the solubility in a solvent decreases when preparing a coating solution. Further, when the molecular weight is high, there is a possibility that the viscosity of the coating solution becomes high and it is difficult to form a uniform film.
Two or more hydrophilic chains having a reactive group at one end may be used in combination.

(Main chain)
The main chain has three or more reactive groups, at least one reactive group can react with the reactive group of the hydrophilic chain at one end to form a chemical bond, and at least two reactive groups react with each other Thus, the compound can be synthesized using a compound capable of forming a chemical bond (first aspect of the present invention). Alternatively, the main chain has two or more reactive groups, and at least one reactive group reacts with the reactive group of the hydrophilic chain to form a chemical bond, and three or more reactive groups. And at least one reactive group can react with the reactive group of compound A to form a chemical bond, and at least two reactive groups can react with each other to form a chemical bond, or three or more reactions. Any of the functional groups can be synthesized in combination with Compound B, which can form a chemical bond by reacting with the reactive group of Compound A (second aspect of the present invention). Compound B may further have a reactive group that can react with the reactive group of the hydrophilic chain to form a chemical bond.
The compound that forms the main chain may be any of a monomer, an oligomer, and a polymer. When two or more types of compounds are used, the mutual bond can be an ionic bond.

As the compound forming the main chain, a compound known as a polymer crosslinking agent can be used. A crosslinking agent is generally a compound that can form a crosslink between polymers by heat. The crosslinking agent is described in “Crosslinking agent handbook” by Shinzo Yamashita, Tosuke Kaneko, published by Taiseisha (1981).
The reactive group of the compound forming the main chain is carboxyl, its salt, carboxylic anhydride group, amino, imino, hydroxyl, epoxy group, aldehyde, methylol, mercapto, isocyanate, block isocyanate group, alkoxysilyl group, ethylene An unsaturated double bond, a coordination bond group, an ester bond or a tetrazole group is preferred.

Examples of compounds having a carboxyl as a reactive group include α, ω-alkanedicarboxylic acids (eg, succinic acid, adipic acid), α, ω-alkenedicarboxylic acids, polycarboxylic acids (eg, 1,2,3-propane). Tricarboxylic acid, 1,2,3,4-butanetetracarboxylic acid, trimellitic acid, polyacrylic acid).
Examples of compounds having amino and imino as reactive groups include amines (eg, butylamine, spermine, diaminocyclohexane, piperazine, aniline, phenylenediamine, 1,2-ethanediamine, diethylenediamine, diethylenetriamine), imines (eg, polyethylene). Imine).

  Examples of compounds having an epoxy group as a reactive group include polyepoxy compounds (eg, ethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, tetraethylene glycol diglycidyl ether, nonaethylene ethylene glycol diglycidyl ether, polyethylene glycol glycidyl ether). Polypropylene glycol glycidyl ether, neopentyl glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, trimethylolpropane triglycidyl ether, sorbitol polyglycidyl ether).

Examples of compounds having hydroxyl as a reactive group include alkylene glycol (eg, ethylene glycol, propylene glycol), oligoalkylene glycol (eg, diethylene glycol, tetraethylene glycol), polyalkylene glycol, polyol (eg, trimethylolpropane, glycerin). , Pentaerythritol, sorbitol, polyvinyl alcohol).
Examples of the compound having an aldehyde as a reactive group include polyaldehyde (eg, glyoxal, terephthalaldehyde).

Examples of compounds having isocyanate and block isocyanate groups as reactive groups include polyisocyanates (eg, tolylene diisocyanate, hexamethylene diisocyanate, diphenylmethane isocyanate, xylylene diisocyanate, polymethylene polyphenyl isocyanate). , Cyclohexyl diisocyanate, cyclohexanephenylene diisocyanate, naphthalene-1,5-diisocyanate, isopropylbenzene-2,4-diisocyanate, polypropylene glycol / tolylene diisocyanate addition reaction), block polyisocyanate compound including.
Examples of the compound having an alkoxysilyl group as a reactive group include a silane coupling agent (eg, tetraalkoxysilane).

Examples of the compound having a coordination bond group as a reactive group include a metal crosslinking agent (eg, aluminum acetylacetonate, copper acetylacetonate, iron (III) acetylacetonate).
Examples of the compound having methylol as a reactive group include a polymethylol compound (eg, trimethylol melamine, pentaerythritol).
Examples of compounds having mercapto as a reactive group include polythiol compounds (eg, dithioerythritol, pentaerythritol tetrakis (2-mercaptoacetate), trimethylolpropane tris (2-mercaptoacetate)).
The compound that forms the main chain is preferably water-soluble.

As the compound forming the main chain, a polymer having a mass average molecular weight of 1,000 to 2,000,000 and 10 or more reactive groups can also be used. By using a polymer for the formation of the main chain, a high molecular weight hydrophilic polymer can be formed with few reactions, and the durability of the hydrophilic layer can be improved.
The polymer preferably has an ionic group (anionic group or cationic group) as a reactive group with another compound constituting the main chain. Examples of anionic groups include carboxylic acid groups, sulfonic acid groups, phosphoric acid groups, phenolic hydroxyl groups and salts thereof. Examples of the cationic group include an amino group, an imino group, and a nitrogen-containing heterocyclic group (eg, pyridinyl, piperidinyl, piperazinyl).
Examples of the polymer having an anionic group include poly (meth) acrylic acid, a salt thereof (eg, sodium salt, ammonium salt), polystyrene sulfonic acid, and a copolymer thereof.
Examples of the polymer having a cationic group include polyvinylamine, polyallylamine, salts thereof (eg, polyallylamine chloride), polyethyleneimine, polyvinylpyrrolidone, and copolymers thereof.
Natural polymers (eg, alginic acid, starch) and semi-synthetic polymers (eg, carboxymethyl cellulose) may be used.

(Bonding of hydrophilic chain and main chain)
When the reactive group at one end of the hydrophilic chain is a carboxyl group or a salt thereof, the main chain or the monomer constituting it is a polyepoxy compound, polyamine compound, polymethylol compound, polyisocyanate compound, block polyisocyanate. It is preferable to use a narate compound or a metal crosslinking agent.
When the reactive group that the hydrophilic chain has at one end is a methylol group, a phenolic hydroxyl group, or a glycidyl group, a polycarboxylic acid compound, a polyamine compound, or a polyhydroxy compound may be used as the main chain or a monomer constituting the main chain. preferable.
When the reactive group which the hydrophilic chain has at one end is an amino group, a polyisocyanate compound, a block polyisocyanate compound, a polyepoxy compound or a polymethylol compound may be used as the main chain or a monomer constituting the main chain. it can.
When the reactive group at one end of the hydrophilic chain is a hydroxyl group, a polyisocyanate compound, a block polyisocyanate compound, a polyaldehyde compound, or a polycarboxylic acid compound should be used as the main chain or the monomer constituting it. Can do.

When the reactive group that the hydrophilic chain has at one end is an alkoxysilyl group, tetraalkoxysilane or polyhydric alcohol can be used as the main chain or a monomer constituting the main chain.
When the reactive group that the hydrophilic chain has at one end is an ethylenically unsaturated double bond, a polythiol compound, an amine, or an imine can be used as the main chain or a monomer constituting the main chain.
In addition to the above reactions, the reaction between the monomers constituting the main chain can also utilize a reaction between epoxy groups.

An ionic bond can also be introduced into the main chain and a linking group between the hydrophilic chain and the main chain. However, the bond between the reactive group at one end of the hydrophilic chain and the linking group, the main chain or the reactive group of the monomer constituting it is preferably a covalent bond.
The reactive group at one end of the hydrophilic chain is an ethylenically unsaturated double bond, the main chain or the monomer constituting it consists of two components, one is an amine or imine, the other is anionic It preferably has a group. The ethylenically unsaturated bond of the hydrophilic chain and the amine or imine can form a covalent bond, and the amine or imine and the main chain having an anionic group or the monomer constituting the same can form an ionic bond.
The reactive group at one end of the hydrophilic chain is an epoxy alkyl group, the main chain or the monomer constituting it is composed of two components, one having a carboxylic acid or phenol and the other having a cationic group. It is also preferable to have it. The epoxy alkyl group of the hydrophilic chain and the carboxylic acid or phenol can form a covalent bond, and the carboxylic acid or phenol and the main chain having a cationic group or a monomer constituting the ionic bond can form an ionic bond.

The reactive group that the hydrophilic chain has at one end is an epoxy alkyl group, the main chain or the monomer constituting it is composed of two components, one is an amine or imine, and the other has an anionic group Is particularly preferred. The epoxy alkyl group of the hydrophilic chain and the amine or imine can form a covalent bond, and the amine or imine and the main chain having an anionic group or the monomer constituting the same can form an ionic bond.
In the three-dimensional molecular structure of the hydrophilic polymer, since only one end of the hydrophilic chain is bonded to the main chain, the hydrophilic chain has a high degree of freedom and a structure with excellent mobility.

[Hydrophilic-hydrophobic conversion agent]
In the embodiment of the hydrophilic image recording layer that can be converted into hydrophobicity, the hydrophilic image recording layer contains a hydrophilic-hydrophobic converting agent.
The hydrophilic-hydrophobic conversion agent is a compound (preferably a polymer) in which the physical property of the compound itself changes from hydrophilic to hydrophobic upon heating, or thermoplastic particles, thermosetting particles, thermoreactive particles or microparticles of hydrophobic compounds. Capsules are preferred.

  The compound that changes from hydrophilic to hydrophobic is preferably a polymer having a functional group that undergoes decarboxylation by heat to change from hydrophilic to hydrophobic (described in JP-A No. 2000-122272). When a compound that changes from hydrophilic to hydrophobic is applied, the contact angle of the airborne water droplets on the coating surface is preferably 20 ° or less before heating, and preferably 65 ° or more after heating.

  The hydrophobic compound constituting the thermoplastic particles, thermosetting particles, and thermoreactive particles is preferably a polymer.

Thermoplastic polymer particles are disclosed in Research Disclosure No. 33303, Jan. 1992, JP-A-9-123387, JP-A-9-131850, JP-A-9-171249, JP-A-9-171250, and European Patent No. 931647. It is described in the specification.
The average particle diameter of the thermoplastic polymer particles is preferably 0.01 to 2.0 μm. The thermoplastic polymer particles are obtained by emulsion polymerization, suspension polymerization or dissolution / dispersion (in which a monomer is dissolved in a water-insoluble organic solvent, this is mixed and emulsified with an aqueous solution containing a dispersant, and further heated. The organic solvent can be synthesized by a method of solidifying into particles while evaporating.

The thermosetting polymer particles are formed using a thermosetting polymer.
The thermosetting polymer includes a resin having a phenol skeleton, a urea resin, a melamine resin, an alkyd resin, an unsaturated polyester resin, a polyurethane resin, and an epoxy resin. A resin having a phenol skeleton, a melamine resin, a urea resin and an epoxy resin are preferred.
The average particle size of the thermosetting polymer particles is preferably 0.01 to 2.0 μm. Thermosetting polymer particles can be produced by a solution dispersion method. Particles can also be formed simultaneously with the synthesis of the thermosetting polymer.

The thermally reactive polymer particles are formed using a polymer having a thermally reactive group.
Thermally reactive groups include radically polymerizable groups (eg, acryloyl, methacryloyl, vinyl, allyl), cationic polymerizable groups (eg, vinyl, vinyloxy), addition reactive groups (eg, isocyanate groups or blocks thereof, epoxy) Group, vinyloxy) and a functional group having an active hydrogen atom as a reaction partner (eg, amino, hydroxyl, carboxyl), a condensation reactive group (eg, carboxyl) and a functional group as a reaction partner (eg, hydroxyl, amino), It contains a ring-opening addition-reactive group (eg, acid anhydride) and a functional group (eg, amino, hydroxyl) as a reaction partner.

In polymer polymerization, thermally reactive groups can be introduced into the polymer particles.
In the case of introducing a thermally reactive group in the polymerization, it is preferable to carry out emulsion polymerization or suspension polymerization of a monomer having a thermally reactive group. Examples of the monomer having a thermally reactive group are allyl methacrylate, allyl acrylate, vinyl methacrylate, vinyl acrylate, 2- (vinyloxy) ethyl methacrylate, p-vinyloxystyrene, p- {2- (vinyloxy) ethyl} styrene, glycidyl. Methacrylate, glycidyl acrylate, 2-isocyanate ethyl methacrylate or its block isocyanate, 2-isocyanate ethyl acrylate or its block isocyanate, 2-aminoethyl methacrylate, 2-aminoethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxy Including ethyl acrylate, acrylic acid, methacrylic acid, maleic anhydride, difunctional acrylate, bifunctional methacrylate. The block isocyanate can be blocked with, for example, alcohol.

A copolymer of a monomer having a thermoreactive group and another monomer (having no thermoreactive group) may be used. Examples of other monomers include styrene, alkyl acrylate, alkyl methacrylate, acrylonitrile, vinyl acetate.
A polymer reaction may be performed after polymer polymerization to introduce a thermally reactive group. The polymer reaction is described in International Publication No. 96/34316.
The average particle size of the polymer particles having a thermoreactive group is preferably 0.01 to 2.0 μm, more preferably 0.05 to 2.0 μm, and most preferably 0.1 to 1.0 μm.

  The microcapsule that functions as a hydrophilic-hydrophobic conversion agent encapsulates a hydrophobic compound. The hydrophobic compound preferably has a thermally reactive group. The thermally reactive group is the same as the thermally reactive group of the polymer particle having a thermally reactive group. Examples of the monomer having a thermoreactive group include a monomer having a plurality of ethylenically unsaturated groups in addition to the monomer of the polymer particle having the thermoreactive group. Monomers having a plurality of ethylenically unsaturated groups are polyhydric alcohol acrylic esters (eg, trimethylolpropane triacrylate, pentaerythritol tetraacrylate), polyhydric alcohol methacrylates (eg, dipentaerythritol dimethacrylate). Itaconic acid ester of polyhydric alcohol (eg, ethylene glycol diitaconate), maleic acid ester of polyhydric alcohol (eg, ethylene glycol dimaleate), polyhydric acrylamide (eg, methylenebisacrylamide).

  Microcapsules can be produced by a known method. The microcapsule is produced by a coacervation method (described in US Pat. Nos. 2,800,047 and 2,800,498), an interfacial polymerization method (British Patent No. 990443, US Pat. No. 3,287,154), 38-19574, 42-446, 42-711), polymer precipitation methods (described in US Pat. Nos. 3,418,250 and 3,660,304), isocyanate polyol wall material A method using an isocyanate wall material (described in US Pat. No. 3,914,511), a method using a urea-formaldehyde-based or urea-formaldehyde-resorcinol-based wall-forming material (US Pat. No. 3,796,669) No. 4001140, No. 4087376, No. 408980 Melamine-formaldehyde resin (described in U.S. Pat. No. 4,025,445), a method using a hydroxycellulose wall material, an in situ method by monomer polymerization (Japanese Patent Publication Nos. 36-9163 and 51-9079) ), Spray drying method (described in each specification of British Patent No. 930422, US Pat. No. 3,111,407), and electrolytic dispersion cooling method (described in each specification of British Patent Nos. 952807 and 967074). Can be adopted.

A water-soluble polymer can be used as a dispersant for stably dispersing the microcapsules in an aqueous medium. As the water-soluble polymer, a natural polymer (eg, polysaccharide, protein), a semi-synthetic polymer (eg, cellulose ether, starch derivative) or a synthetic polymer can be used. Examples of polysaccharides include gum arabic and sodium alginate. Examples of proteins include casein and gelatin. Examples of the cellulose ether include carboxymethyl cellulose and methyl cellulose. The synthetic polymer is preferably a polymer having a hydrocarbon main chain (eg, polyvinyl alcohol and a modified product thereof, polyacrylamide and a derivative thereof, polyvinyl pyrrolidone). Copolymers may be used. Examples of copolymers are ethylene / vinyl acetate copolymer, styrene / maleic anhydride copolymer, ethylene / maleic anhydride copolymer, isobutylene / maleic anhydride copolymer, ethylene / acrylic acid copolymer, vinyl acetate. / Contains acrylic acid copolymer.
It is preferable that the water-soluble polymer does not react with the isocyanate compound or has extremely low reactivity. When using a polymer (for example, gelatin) highly reactive with an isocyanate compound, it is preferable to remove or block a reactive functional group in advance.

  The microcapsule wall preferably has a three-dimensional crosslink and swells with a solvent. The wall material of the microcapsule is preferably polyurea, polyurethane, polyester, polycarbonate, polyamide, a copolymer or a mixture thereof, and more preferably polyurea, polyurethane, or a copolymer or mixture thereof. A compound having a thermally reactive group may be introduced into the microcapsule wall.

The average particle size of the microcapsules is preferably 0.01 to 3.0 μm, more preferably 0.05 to 2.0 μm, and most preferably 0.10 to 1.0 μm.
The addition amount of the polymer particles and microcapsules to the hydrophilic image recording layer is preferably 50% by mass or more, and more preferably 70 to 98% by mass in terms of solid content in terms of solid content.

When microcapsules are added to the hydrophilic image recording layer, a solvent capable of dissolving the inclusions and swelling the wall material can be added to the microcapsule dispersion medium. In the case of microcapsules comprising polyurea or polyurethane walls, the solvent is alcohol (eg, methanol, ethanol, propanol, tert-3-butanol), ether (eg, tetrahydrofuran, propylene glycol monomethyl ether, ethylene glycol diethyl ether, ethylene glycol monomethyl). Ethers), acetals, esters (eg, methyl lactate, ethyl lactate, γ-butyl lactone), ketones (methyl ethyl ketone), polyhydric alcohols, amides (eg, dimethylformamide, N, N-dimethylacetamide), amines and fatty acids are preferred. . Two or more solvents may be used in combination.
The addition amount of the solvent is preferably 5 to 95% by mass of the coating solution, more preferably 10 to 90% by mass, and most preferably 15 to 85% by mass.

[Photothermal conversion agent]
In the aspect of the hydrophilic image recording layer that can be converted to hydrophobicity, the hydrophilic image recording layer preferably contains a photothermal conversion agent.
The photothermal conversion agent is a substance having a function of generating heat by absorbing light and converting light energy into heat energy. The light is preferably infrared light. In other words, the photothermal conversion agent is preferably an infrared absorber.
Pigments, dyes or metal fine particles that can absorb infrared light can be preferably used as the photothermal conversion agent. When microcapsules are used as the particles, it is particularly preferable to use an infrared absorbing dye as the photothermal conversion agent.

  As for infrared absorbing dyes, “Dye Handbook” edited by the Society of Synthetic Organic Chemistry, published in 1970, “Chemical Industry”, May 1986, p. Nos. 45 to 51, “Near-infrared absorbing dyes” and “Development and market trends of functional dyes in the 1990s”, Chapter 2, Section 2.3 (1990) CMC. Preferred infrared absorbing dyes are azo dyes, metal complex azo dyes, pyrazolone azo dyes, naphthoquinone dyes (Japanese Patent Laid-Open Nos. 58-112793, 58-224793, 59-48187, 59-73996, 60- Nos. 52940 and 60-63744), anthraquinone dyes, phthalocyanine dyes (described in JP-A-11-235883), squarylium dyes (described in JP-A-58-112792), pyrylium dyes (US Pat. No. 3,881,924). Nos. 4283475, JP-A 57-142645, 58-181051, 58-220143, 59-41363, 59-84248, 59-84249, 59 -146033, 59-146061, and JP-B-5-13514 JP-described Nos. 5-19702), carbonium dyes, quinone imine dyes, methine dyes (JP 58-173696, the same 58-181690 JP, is the publication) of Nos. 58-194595. Methine dyes include cyanine dyes (described in JP-A Nos. 58-125246, 59-84356, and JP-A-60-78787).

Infrared absorbing dyes are also described in US Pat. Nos. 4,756,993 and 5,156,938, and JP-A-10-268512 and JP-A-2004-306582. Commercially available infrared absorbing dyes (for example, Epolite III-178, Epolite III-130, Epolite III-125, manufactured by Eporin) may be used.
The photothermal conversion agent may be encapsulated in microcapsules. The addition amount is preferably 0.001 to 50% by mass, more preferably 0.005 to 30% by mass, and most preferably 0.01 to 10% by mass with respect to the total solid content of the hydrophilic image recording layer.

[Polymerization initiator]
In order to polymerize the polymerizable compound, a polymerization initiator can be used.
The polymerization initiator refers to a compound that generates radicals by light, heat, or both, and initiates and accelerates polymerization of a compound having a polymerizable unsaturated group. As the polymerization initiator, a known thermal polymerization initiator or a compound having a small total of bond dissociation energy can be used.
The compound that generates radicals is preferably a compound (thermal radical generator) that generates radicals by thermal energy and initiates and accelerates polymerization of a compound having a polymerizable unsaturated group. As the thermal radical generator, a known polymerization initiator or a compound having a bond having a small bond dissociation energy can be appropriately selected and used.

Two or more compounds that generate radicals may be used in combination.
A compound that generates radicals is described in JP-A-2004-306582. Examples of compounds that generate radicals are halogenated organic compounds, carbonyl compounds, organic peroxides, azo polymerization initiators, azide compounds, metallocene compounds, hexaarylbiimidazole compounds, organic boric acid compounds, disulfonic acid compounds, oximes. Includes ester compounds and oxime salt compounds. Onium salts are most preferred.

[Support]
Supports are paper, polymer (eg, cellulose ester, polyester, polyethylene, polystyrene, polypropylene, polycarbonate, polyvinyl acetal) film, metal (eg, aluminum, zinc, copper) plate, polymer laminated paper, metal deposited. A polymer film on which paper or metal is deposited can be used. Polymer films and metal plates are preferred, polyester films and aluminum plates are more preferred, and aluminum plates are most preferred.

The aluminum plate is a pure aluminum plate or an aluminum alloy plate. Examples of foreign elements contained in the aluminum alloy include silicon, iron, manganese, copper, magnesium, chromium, zinc, bismuth, nickel, and titanium. The amount of the different element in the alloy is 10% by mass or less.
The thickness of the aluminum plate is preferably 0.1 mm to 0.8 mm, more preferably 0.15 mm to 0.6 mm, and most preferably 0.2 mm to 0.4 mm.

The aluminum plate is preferably subjected to a roughening treatment.
Before the roughening treatment, a degreasing treatment for removing the rolling oil on the surface may be performed. The degreasing treatment can be performed using a surfactant, an organic solvent, or an alkaline aqueous solution.
The surface roughening treatment includes mechanical surface roughening treatment, electrochemical surface roughening treatment, and chemical surface roughening treatment.
The mechanical surface roughening treatment includes a ball polishing method, a brush polishing method, a blast polishing method, and a buff polishing method.
The electrochemical surface roughening treatment can be performed, for example, by alternating current or direct current in an electrolytic solution containing an acid (eg, hydrochloric acid or nitric acid). A method using a mixed acid (described in JP-A-54-63902) can also be employed.

A transfer method of transferring the concavo-convex shape with a roll provided with concavo-convex in the aluminum rolling step can also be performed. Unevenness can also be provided by mechanical embossing. Furthermore, a rough surface may be provided by forming convex portions on the surface by gravure printing or the like. A layer containing solid fine particles (matting agent) may be provided with a rough surface on the support surface by means such as coating or printing. The solid fine particles can be contained (internally added) in the polymer film at the stage of producing the polymer film, and irregularities can be formed on the surface of the polymer film. The rough surface can also be formed by solvent treatment, corona discharge treatment, plasma treatment, electron beam irradiation treatment, and X-ray irradiation treatment. You may implement combining the above means. A means for forming a rough surface by sandblasting or resin printing, or a means for forming irregularities by adding solid fine particles is particularly preferred.
The roughened aluminum plate is preferably subjected to alkali etching treatment and further neutralization treatment.

The aluminum plate is preferably anodized.
As the electrolyte used for the anodizing treatment of the aluminum plate, various electrolytes that form a porous oxide film can be used. In general, sulfuric acid, hydrochloric acid, oxalic acid, chromic acid or a mixed acid thereof is used. The concentration of these electrolytes is appropriately determined depending on the type of electrolyte.

The preferred conditions for the anodizing treatment are as follows: electrolyte concentration is 1 to 80% by mass, liquid temperature is 5 to 70 ° C., current density is 5 to 60 A / dm ² , voltage is 1 to 100 V, and electrolysis time is 10 seconds to 5 minutes. is there. The amount of anodized film formed is preferably from 1.0 to 5.0 g / ^{m 2,} more preferably 1.5 to 4.0 g / ^{m 2.}

[Other layers]
An undercoat layer may be provided between the support and the hydrophilic layer. A function of improving adhesion can be imparted to the undercoat layer. The undercoat layer is described in JP-A-6-316183, JP-A-8-272088, JP-A-9-179111, and JP-A-2001-199175.
A protective layer may be provided on the hydrophilic image recording layer. The protective layer can be formed using a water-soluble polymer (eg, polyvinyl alcohol) having excellent crystallinity. The protective layer is described in U.S. Pat. No. 2,345,831 and JP-A-55-49729.

[Original for lithographic printing]
In an embodiment having a hydrophilic image recording layer, printing is performed using a lithographic printing original plate comprising a hydrophilic image recording layer and a support.
Specifically, a part of the hydrophilic image recording layer of the lithographic printing original plate having a hydrophilic image recording layer and a support is converted into a hydrophobic region corresponding to the image, and the surface of the image recording layer is made hydrophilic. A lithographic printing plate having a hydrophilic region and a hydrophobic region is made, dampening water and oil-based ink are supplied to the lithographic printing plate, and dampening water adheres on the hydrophilic region, and the lithographic printing plate is placed on the hydrophobic region. Print with oil-based ink attached.

In an embodiment in which the hydrophilic layer and the support constitute a hydrophilic substrate, a lithographic printing original plate can be obtained by providing an image recording layer on the hydrophilic layer.
The image recording layer can be classified into a positive type in which the solubility in an alkaline aqueous solution is improved by exposure and a negative type in which the solubility in an alkaline aqueous solution is decreased. Both positive and negative types are known. If the unexposed or exposed area of the image recording layer can be removed with oil-based ink or fountain solution, direct printing is performed without performing development processing (processing to remove the unexposed or exposed area of the image recording layer) after exposure. It can also be installed on a machine and printed. Such an image recording layer has also been proposed.

Specifically, from a lithographic printing plate comprising a hydrophilic substrate having a hydrophilic layer and a support and a hydrophobic image recording layer provided on the hydrophilic layer, a partial region of the hydrophobic image recording layer is imaged. A lithographic printing plate having a hydrophilic region composed of the exposed hydrophilic layer and a hydrophobic region composed of the remaining hydrophobic image recording layer is made in accordance with the lithographic printing plate, and dampening water and oil-based ink are applied to the lithographic printing plate. And dampening water adheres on the hydrophilic area, and printing is performed in a state where oil-based ink adheres on the hydrophobic area.
The hydrophobic image recording layer provided on the hydrophilic layer is a compound (preferably a polymer) in which the physical property of the compound itself changes from hydrophilic to hydrophobic by heating, or a thermoplastic particle, a thermosetting particle or a hydrophobic compound. Microcapsules can be included. These details are the same as the hydrophilic-hydrophobic conversion agent added to the hydrophilic image recording layer.
The hydrophobic image recording layer can also contain a photothermal conversion agent and a polymerization initiator. The details of the photothermal conversion agent and the polymerization initiator are the same as those of the photothermal conversion agent and the polymerization initiator that can be added to the hydrophilic image recording layer.

A lithographic printing plate is formed by directly forming a hydrophobic region on a hydrophilic layer (for example, forming a hydrophobic toner image by an electrophotographic recording method by applying hydrophobic oil droplets in an image form by an ink jet method). Can be made.
Specifically, a hydrophobic substance is attached to a hydrophilic substrate having a hydrophilic layer and a support in accordance with an image, and a hydrophilic region consisting of the hydrophilic layer surface and a hydrophobic substance are attached. A lithographic printing plate having a hydrophilic region, supplying dampening water and oil-based ink to the lithographic printing plate, dampening water adhering to the hydrophilic region, and oil-based ink adhering to the hydrophobic region Print while printing.

[Example 1]
(Synthesis of terminal carboxylic acid hydrophilic chain (CA-1))
An aqueous solution obtained by dissolving 147.8 g of 3-sulfopropyl ester potassium salt of methacrylic acid, 3.82 g of mercaptopropionic acid, 0.582 g of a polymerization initiator (VA-044 manufactured by Wako Pure Chemical Industries, Ltd.) in 151.5 g of water, Water kept at 50 ° C. under nitrogen atmosphere: Dropped into 151.5 g over 2 hours, further dropwise addition, stirred at 50 ° C. for 2 hours, and then at 60 ° C. for 2 hours, cooled, then to acetone: 4.5 L When gradually added dropwise, a white solid precipitates.
The obtained solid was filtered and dried to obtain 145 g of a terminal carboxylic acid hydrophilic chain (CA-1). The acid value after drying was 0.086 meq / g.

(Preparation of aluminum support)
Al: 99.5% by mass or more, Fe: 0.30% by mass, Si: 0.10% by mass, Ti: 0.02% by mass, Cu: 0.013% by mass, the balance being JIS of inevitable impurities The molten A1050 aluminum alloy was subjected to a cleaning treatment and cast. As the cleaning treatment, degassing treatment was performed to remove unnecessary gas such as hydrogen in the molten metal, and further ceramic tube filter treatment was performed. The casting method was a DC casting method. The surface of the ingot having a thickness of 500 mm was chamfered by 10 mm, and homogenized at 550 ° C. for 10 hours so that the intermetallic compound would not become coarse. Subsequently, it was hot-rolled at 400 ° C., subjected to intermediate annealing at 500 ° C. for 60 seconds in a continuous annealing furnace, and then cold-rolled to obtain an aluminum rolled plate having a thickness of 0.30 mm. By controlling the roughness of the rolling roll, to control the center line average roughness R _a after cold rolling to 0.2 [mu] m. Then, it applied to the tension leveler in order to improve planarity. The obtained aluminum plate was subjected to the following surface treatment.

First, in order to remove the rolling oil on the surface of the aluminum plate, a degreasing treatment is performed at 50 ° C. for 30 seconds using a 10 mass% sodium aluminate aqueous solution, and then, at 30 ° C. for 30 seconds using a 30 mass% nitric acid aqueous solution. Then, neutralization and smut removal treatment were performed.
Next, a surface roughening treatment was performed in order to improve the adhesion between the image recording layer and the support and to provide water retention to the non-image area. Specifically, a current density of 20 A is passed through an aluminum plate web through an aqueous solution (liquid temperature 45 ° C.) containing 1% by mass of nitric acid and 0.5% by mass of aluminum nitrate supplied to the indirect power supply cell. Electrolytic surface roughening treatment was carried out by electrolyzing the aluminum plate with an alternating waveform of / dm ² and a duty ratio of 1: 1 so that the amount of electricity at the time of anode was 240 C / dm ² .
Further, an etching treatment was performed at 35 ° C. for 30 seconds using a 10 mass% sodium hydroxide aqueous solution, and then neutralization and smut removal treatment were performed at 50 ° C. for 30 seconds using a 30 mass% sulfuric acid aqueous solution.

Thereafter, an anodizing treatment was performed to improve wear resistance, chemical resistance and water retention. Specifically, electrolysis is performed by direct current having a current density of 14 A / dm ² while passing through a web of an aluminum plate through a 20% by mass sulfuric acid aqueous solution (liquid temperature: 35 ° C.) supplied to the indirect power feeding cell. An anodized film of 0.5 g / m ² was produced.
Then, in order to ensure the hydrophilic property of a non-image part, the silicate process was performed for 15 second at 70 degreeC using the 1.5 mass% No. 3 sodium silicate aqueous solution. The adhesion amount of Si was 10 mg / m ² . Then, it washed with water and the support body was obtained. Center line average roughness R _a of the support obtained was 0.25 [mu] m.

(Preparation of microcapsule dispersion)
As oil phase components, trimethylolpropane and xylene diisocyanate adduct (Mitsui Takeda Chemical Co., Ltd., Takenate D-110N) 10 g, pentaerythritol triacrylate (Nippon Kayaku Co., Ltd., SR444) 3.15 g, 0.35 g of the following infrared absorber (1), 1 g of 3- (N, N-diethylamino) -6-methyl-7-anilinofluorane (ODB manufactured by Yamamoto Kasei), the following polymerization initiator (1) 0. 75 g and 0.1 g of Pionein A-41C (manufactured by Takemoto Yushi Co., Ltd.) were dissolved in 17 g of ethyl acetate. As an aqueous phase component, 40 g of a 4% by mass aqueous solution of carboxylic acid-modified polyvinyl alcohol (KL-506, manufactured by Kuraray Co., Ltd.) was prepared. The oil phase component and the aqueous phase component were mixed and emulsified for 10 minutes at 12000 rpm using a homogenizer. The obtained emulsion was added to 25 g of distilled water, stirred at room temperature for 30 minutes, and then stirred at 40 ° C. for 3 hours. The microcapsule liquid (1) thus obtained was diluted with distilled water so that the solid content concentration became 20% by mass. The average particle size was 0.4 μm.

(Formation of hydrophilic layer)
A hydrophilic layer coating solution having the following composition is bar-coated on the support and then oven-dried at 140 ° C. for 10 minutes to form a hydrophilic layer having a dry coating amount of 2.0 g / m ² for lithographic printing. An original plate was prepared.

────────────────────────────────────────
Hydrophilic layer coating solution ────────────────────────────────────────
100g of water
The above microcapsule dispersion (in terms of solid content) 6.0 g
2.5 g of hydrophilic chain (CA-1) having a reactive group at one end
Compound forming main chain (1) 2.5 g
Compound (2) forming main chain 1.0 g
Surfactant (diethylhexyl sulfosuccinate sodium salt) 0.2g
────────────────────────────────────────

[Example 2]
(Synthesis of terminal carboxylic acid hydrophilic chain (CA-2))
30 g of acrylamide and 3.8 g of 3-mercaptopropionic acid are dissolved in 70 g of ethanol, and the temperature is raised to 60 ° C. in a nitrogen atmosphere, and 300 mg of 2,2-azobisisobutylnitrile (thermal polymerization initiator, AIBN) is added for 6 hours. Reacted. After the reaction, the white precipitate was filtered and sufficiently washed with methanol to obtain 30.8 g of a terminal carboxylic acid hydrophilic chain (CA-2) (acid value 0.787 meq / g, molecular weight 1.29 × 10 ³ ).

(Preparation of original plate for lithographic printing)
A lithographic printing original plate was prepared in the same manner as in Example 1 except that the hydrophilic chain was changed to (CA-2).

[Example 3]
A lithographic printing plate precursor was prepared in the same manner as in Example 1 except that the hydrophilic chain was changed to (AM-2) and the compound (1) was changed to the compound (3).

[Example 4]
A lithographic printing original plate was prepared in the same manner as in Example 1 except that the hydrophilic chain was changed to (DB-1), compound (1) was changed to compound (3), and compound (2) was changed to compound (4). Produced.

[Example 5]
A lithographic printing plate precursor was prepared in the same manner as in Example 1 except that the hydrophilic layer coating solution of Example 1 was changed to the following hydrophilic layer coating solution.

────────────────────────────────────────
Hydrophilic layer coating solution ────────────────────────────────────────
100g of water
Microcapsule dispersion used in Example 1 (in terms of solid content) 6.0 g
2.5 g of hydrophilic chain (CA-1) having a reactive group at one end
Sorbitol polyglycidyl ether (compound (5) forming main chain, Denacol EX-614B, manufactured by Nagase Mtex Co., Ltd.) 3.5 g
Surfactant (diethylhexyl sulfosuccinate sodium salt) 0.2g
────────────────────────────────────────

[Example 6]
A lithographic printing plate precursor was prepared in the same manner as in Example 1 except that the hydrophilic layer coating solution of Example 1 was changed to the following hydrophilic layer coating solution.

────────────────────────────────────────
Hydrophilic layer coating solution ────────────────────────────────────────
100g of water
Microcapsule dispersion used in Example 1 (in terms of solid content) 6.0 g
2.5 g of hydrophilic chain (CA-1) having a reactive group at one end
Compound forming main chain (1) 2.5 g
Compound (4) forming main chain 1.0 g
Surfactant (diethylhexyl sulfosuccinate sodium salt) 0.2g
────────────────────────────────────────

[Example 7]
A lithographic printing plate precursor was prepared in the same manner as in Example 1 except that the hydrophilic layer coating solution of Example 1 was changed to the following hydrophilic layer coating solution.

────────────────────────────────────────
Hydrophilic layer coating solution ────────────────────────────────────────
100g of water
Microcapsule dispersion used in Example 1 (in terms of solid content) 6.0 g
2.5 g of hydrophilic chain (CA-1) having a reactive group at one end
Compound (1) forming main chain 3.0 g
0.5 g of polyacrylic acid (compound forming main chain (6), weight average molecular weight 5000)
Surfactant (diethylhexyl sulfosuccinate sodium salt) 0.2g
────────────────────────────────────────

[Comparative Example 1]
A lithographic printing plate precursor was prepared in the same manner as in Example 1 except that the hydrophilic chain (CA-1) of Example 1 was not used.

[Comparative Example 2]
A lithographic printing original plate was prepared in the same manner as in Example 1 except that the compound (2) of Example 1 was not used.

[Comparative Example 3]
A lithographic printing original plate was prepared in the same manner as in Example 7 except that the hydrophilic chain (CA-1) of Example 7 was not used.

(Exposure and printing)
The resulting lithographic printing plate precursor was exposed with a Trend setter 3244VX manufactured by Creo equipped with a water-cooled 40 W infrared semiconductor laser under the conditions of an output of 9 W, an outer drum rotating speed of 210 rpm, and a resolution of 2400 dpi. The exposure image includes a thin line chart. The obtained exposed original plate was attached to a cylinder of a printing machine SOR-M manufactured by Heidelberg without developing. Dampening solution (EU-3 (Etch solution manufactured by Fuji Photo Film Co., Ltd.) / Water / isopropyl alcohol = 1/89/10 (volume ratio)) and TRANS-G (N) black ink (Dainippon Ink and Chemicals, Inc.) After the fountain solution was supplied, 500 sheets were printed at a printing speed of 6000 sheets per hour. Thereafter, the ink was once adhered to the plate surface, and dampening water was supplied to measure the number of sheets where the ink disappeared from the plate surface and no scumming occurred on the non-image portion of the printed matter. Thereafter, printing was performed until scumming occurred.

(1) Soil stain At the time of starting printing 500 sheets, the ink adhesion amount in the non-image area on the printed matter was visually evaluated. Then, it was judged whether the ink was not adhered at all and the state where the ink was not soiled was a state where the ink adhered even a little.

(2) Ink wiping Printing was performed by the method described above, and the number of ink wiping was measured. The hydrophilic layer having superior hydrophilicity has a smaller number of inks.

(3) Printing durability When the non-image area was worn out and scumming occurred, the printing was completed, and the number of printed sheets up to that point was measured. The greater the strength of the hydrophilic layer, the greater the number of printed sheets and the better the printing durability.
The results are shown in Table 1.

Table 1 ─────────────────────────────────────────
Lithographic printing Ink master plate Hydrophilic chain Main chain-forming compound Soil stain Number of sheets to be printed Number of printings ────────────────────────────── ───────────
Example 1 CA-1 (1) + (2) None 10 sheets 10,000 sheets Example 2 CA-2 (1) + (2) None 5 sheets 12000 sheets Example 3 AM-2 (2) + (3) None 15 sheets 12,000 sheets Example 4 DB-1 (3) + (4) None 20 sheets 12000 sheets Example 5 CA-1 (5) None 15 sheets 15000 sheets Example 6 CA-1 (1) + (4) None 10 sheets 10,000 sheets Example 7 CA-1 (6) + (1) None 20 sheets 15000 sheets Comparative example 1 None (1) + (2) None 200 sheets 1000 sheets Comparative example 2 CA-1 (1) Yes Unprintable 0 sheets Comparative example 3 None (6) + (1) Available 500 sheets 5000 sheets ───────────────────────────────── ────────
(註)
Compound (5): Sorbitol polyglycidyl ether compound (6): Polyacrylic acid

[Example 8]
(Formation of hydrophilic layer)
A hydrophilic layer coating solution having the following composition was bar coated on the support prepared in Example 1, and then oven dried at 140 ° C. for 10 minutes to form a hydrophilic layer having a dry coating amount of 2.0 g / m ^2. Thus, an original plate for lithographic printing was prepared.

────────────────────────────────────────
Hydrophilic layer coating solution ────────────────────────────────────────
100g of water
Microcapsule dispersion used in Example 1 (in terms of solid content) 6.0 g
2.5 g of hydrophilic chain (EP-1) having a reactive group at one end
Polyethyleneimine with a weight average molecular weight of 10,000 (compound A1 forming the main chain) 2.0 g
1.5 g of 1,2,3,4-butanetetracarboxylic acid (compound B1 forming the main chain)
Surfactant (diethylhexyl sulfosuccinate sodium salt) 0.2g
────────────────────────────────────────

[Example 9]
A lithographic printing plate precursor was prepared in the same manner as in Example 8 except that the hydrophilic layer coating solution having the following composition was used.

────────────────────────────────────────
Hydrophilic layer coating solution ────────────────────────────────────────
100g of water
Microcapsule dispersion used in Example 1 (in terms of solid content) 6.0 g
2.5 g of hydrophilic chain (CA-1) having a reactive group at one end
3,6,9-tetraaza-1,11-undecanediamine (compound A2 forming main chain) 2.5 g
1.0 g of 1,2,3,4-butanetetracarboxylic acid (compound B1 forming the main chain)
Surfactant (diethylhexyl sulfosuccinate sodium salt) 0.2g
────────────────────────────────────────
[Example 10]
A lithographic printing plate precursor was prepared in the same manner as in Example 8, except that the hydrophilic chain (EP-1) in Example 8 was changed to (CA-1).

[Example 11]
A lithographic printing plate precursor was prepared in the same manner as in Example 8 except that the hydrophilic layer coating solution having the following composition was used.

────────────────────────────────────────
Hydrophilic layer coating solution ────────────────────────────────────────
100g of water
Microcapsule dispersion used in Example 1 (in terms of solid content) 6.0 g
2.5 g of hydrophilic chain (AM-3) having a reactive group at one end
2.0 g of polyacrylic acid having a weight average molecular weight of 10,000 (compound A3 forming the main chain)
3,6,9-tetraaza-1,11-undecanediamine (compound B2 forming main chain) 1.5 g
Surfactant (diethylhexyl sulfosuccinate sodium salt) 0.2g
────────────────────────────────────────

[Example 12]
A lithographic printing plate precursor was prepared in the same manner as in Example 9, except that the hydrophilic chain (CA-1) in Example 9 was changed to (EP-1).

[Example 13]
A lithographic printing original plate was produced in the same manner as in Example 11 except that the hydrophilic chain (AM-3) in Example 11 was changed to (EP-1).

[Example 14]
A lithographic printing plate precursor was prepared in the same manner as in Example 8 except that the hydrophilic layer coating solution of Example 8 was changed to the following hydrophilic layer coating solution.

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Hydrophilic layer coating solution ────────────────────────────────────────
100g of water
Microcapsule dispersion used in Example 1 (in terms of solid content) 6.0 g
2.5 g of hydrophilic chain (EP-1) having a reactive group at one end
Polyethyleneimine with a weight average molecular weight of 10,000 (compound A1 forming the main chain) 2.0 g
1.5 g of polyacrylic acid having a weight average molecular weight of 5000 (compound B3 forming the main chain)
Surfactant (diethylhexyl sulfosuccinate sodium salt) 0.2g
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(Exposure and printing)
The obtained lithographic printing original plate was exposed with a Trend setter 3244VX manufactured by Creo equipped with a water-cooled 40 W infrared semiconductor laser under the conditions of an output of 9 W, an outer drum rotating speed of 210 rpm, and a resolution of 2400 dpi. The exposure image includes a thin line chart. The obtained exposed original plate was attached to a cylinder of a printing machine SOR-M manufactured by Heidelberg without developing. Dampening solution (EU-3 (Etch solution manufactured by Fuji Photo Film Co., Ltd.) / Water / isopropyl alcohol = 1/89/10 (volume ratio)) and TRANS-G (N) black ink (Dainippon Ink and Chemicals, Inc.) After the fountain solution was supplied, 500 sheets were printed at a printing speed of 6000 sheets per hour. Thereafter, the ink was once adhered to the plate surface, and dampening water was supplied to measure the number of sheets where the ink disappeared from the plate surface and no scumming occurred on the non-image portion of the printed matter. Thereafter, printing was performed until scumming occurred.

(1) Soil stain At the time of starting printing 500 sheets, the ink adhesion amount in the non-image area on the printed matter was visually evaluated. Then, it was judged whether the ink was not adhered at all and the state where the ink was not soiled was a state where the ink adhered even a little.

(2) Ink wiping Printing was performed by the method described above, and the number of ink wiping was measured. The hydrophilic layer having superior hydrophilicity has a smaller number of inks.

(3) Printing durability When the non-image area was worn out and scumming occurred, the printing was completed, and the number of printed sheets up to that point was measured. The greater the strength of the hydrophilic layer, the greater the number of printed sheets and the better the printing durability.
The results are shown in Table 2.

Table 2 ─────────────────────────────────────────
Lithographic printing Ink master plate Hydrophilic chain Main chain-forming compound Soil stain Number of sheets to be printed Number of printings ────────────────────────────── ───────────
Example 8 EP-1 A1 + B1 None 15 sheets 18000 sheets Example 9 CA-1 A2 + B1 None 10 sheets 10,000 sheets Example 10 CA-1 A1 + B1 None 5 sheets 15000 sheets Example 11 AM-3 A3 + B2 None 10 sheets 18000 sheets Example 12 EP-1 A2 + B1 None 15 sheets 12,000 sheets Example 13 EP-1 A3 + B2 None 20 sheets 20000 sheets Example 14 EP-1 A1 + B3 None 15 sheets 18000 sheets ─────────────── ────────────────────────
(註)
Compound A1: Polyethyleneimine compound A2 having a mass average molecular weight of 10,000 A2: 3,6,9-tetraaza-1,11-undecanediamine compound A3: Polyacrylic acid compound B1: 1,2,3,4 having a mass average molecular weight of 10,000 -Butanetetracarboxylic acid compound B2: 3,6,9-tetraaza-1,11-undecanediamine compound B3: polyacrylic acid having a mass average molecular weight of 5000

[Example 14]
(Preparation of hydrophilic substrate)
The surface of a polyethylene terephthalate film having a thickness of 0.24 mm was subjected to corona discharge treatment to obtain a support.
A hydrophilic layer coating solution having the following composition was bar coated on the support and then oven dried at 140 ° C. for 10 minutes to form a hydrophilic layer having a dry coating amount of 1.0 g / m ² .

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Hydrophilic layer coating solution ────────────────────────────────────────
2500 g of water
60 g of hydrophilic chain (CA-1) having a reactive group at one end
25 g of the compound forming the main chain (1)
20 g polyacrylic acid with a weight average molecular weight of 100,000
20% by weight aqueous dispersion of colloidal silica (Snowtex C, manufactured by Nissan Chemical Co., Ltd.)
1200g
5% by weight aqueous solution of surfactant (diethylhexyl sulfosuccinate sodium salt)
20g
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(Preparation of photosensitive solution)
A photosensitive solution having the following composition was prepared.

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Photosensitive solution (1)
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Binder polymer (1) 16g
Polymerization initiator (2) 10 g
Infrared absorbing dye (1) used in Example 1 2 g
Polymerizable monomer (Aronix M-215 (manufactured by Toa Gosei Co., Ltd.)) 40 g
Fluorosurfactant (1) 4g
110g of methyl ethyl ketone
860 g of 1-methoxy-2-propanol
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(Preparation of microcapsule dispersion)
As an oil phase, trimethylolpropane and xylene diisocyanate adduct (Mitsui Takeda Chemical Co., Ltd., Takenate D-110N, 75% ethyl acetate solution) 10 g, ethylenically unsaturated monomer (Aronix M-215, Toagosei ( Co., Ltd.) 6.00 g and surfactant (Pionin A-41C, Takemoto Yushi Co., Ltd.) 0.12 g were dissolved in ethyl acetate 16.67 g.
As an aqueous phase, 37.5 g of a 4 mass% aqueous solution of polyvinyl alcohol (PVA-205, manufactured by Kuraray Co., Ltd.) was prepared.
The oil phase and the aqueous phase were mixed and emulsified for 10 minutes at 12000 rpm using a homogenizer. The obtained emulsion was added to 25 g of distilled water, stirred at room temperature for 30 minutes, and then stirred at 40 ° C. for 2 hours. The microcapsule solution thus obtained was diluted with distilled water so that the solid content concentration was 15% by mass. The average particle size was 0.2 μm.

(Preparation of microcapsule solution)
A microcapsule solution having the following composition was prepared.

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Microcapsule solution ─────────────────────────────────────────
260 g of the prepared microcapsule dispersion
240g of water
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(Formation of hydrophobic image recording layer)
A coating solution for the hydrophobic image recording layer was prepared by mixing and stirring the photosensitive solution and the microcapsule solution.
Immediately after preparation of the coating solution, a bar was applied onto the produced hydrophilic substrate. The coating layer was oven dried at 100 ° C. for 60 seconds to form a hydrophobic image recording layer having a dry coating amount of 1.0 g / m ² .

(Preparation of inorganic particle dispersion)
6.4 g of synthetic mica (Somasif ME-100, manufactured by Co-op Chemical) was added to 193.6 g of ion-exchanged water, and dispersed using an homogenizer until the average particle size (measured by a laser scattering method) was 3 μm. The aspect ratio of the obtained dispersed inorganic particles was 100 or more.

(Preparation of on-press development type lithographic printing original plate)
A protective layer coating having the following composition was bar-coated on the image recording layer and oven-dried at 120 ° C. for 60 seconds to form a protective layer having a dry coating amount of 0.15 g / m ² .
In this way, an on-press development type lithographic printing original plate was prepared.

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Protective layer coating solution ────────────────────────────────────────
Inorganic particle dispersion 150g
Polyvinyl alcohol (PVA105, manufactured by Kuraray Co., Ltd., degree of saponification: 98.5 mol%, degree of polymerization: 500) 6 g
Polyvinylpyrrolidone (K30, manufactured by Tokyo Chemical Industry Co., Ltd., mass average molecular weight: 40,000)
1g
Vinylpyrrolidone / vinyl acetate copolymer (LUVITEC VA64W, manufactured by ICP, copolymerization ratio = 6/4) 1 g
Nonionic surfactant (Emalex 710, manufactured by Nippon Emulsion Co., Ltd.) 1g
600g of ion exchange water
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(Print evaluation)
The obtained lithographic printing original plate was exposed with a Trend setter 3244VX manufactured by Creo equipped with a water-cooled 40 W infrared semiconductor laser under the conditions of an output of 9 W, an outer drum rotating speed of 210 rpm, and a resolution of 2400 dpi. The exposure image includes a thin line chart. The obtained exposed original plate was attached to a cylinder of a printing machine SOR-M manufactured by Heidelberg without developing. Dampening solution (EU-3 (Etch solution manufactured by Fuji Photo Film Co., Ltd.) / Water / isopropyl alcohol = 1/89/10 (volume ratio)) and TRANS-G (N) black ink (Dainippon Ink and Chemicals, Inc.) After the fountain solution and the ink were supplied, printing was performed at a printing speed of 6000 sheets per hour. As a result, up to 10,000 sheets were printed with no stains on the non-image area.

[Example 15]
(Manufacture of resin particles)
A mixed solution of 14 g of polydodecyl methacrylate, 100 g of vinyl acetate, 4.0 g of octadecyl methacrylate and 286 g of ISOPAR H was heated to a temperature of 70 ° C. while stirring under a nitrogen stream. 1.5 g of 2,2′-azobis (isovaleronitrile) was added as a polymerization initiator and reacted for 4 hours. Further, after adding 0.8 g of 2,2′-azobis (isobutyronitrile), the mixture was heated to a temperature of 80 ° C. and reacted for 2 hours, followed by 2,2′-azobis (isobutyronitrile) 0 .6 g was added and reacted for 2 hours. Thereafter, the temperature was raised to 100 ° C., and the mixture was stirred as it was for 1 hour to distill off unreacted monomers. After cooling, the white dispersion obtained through a 200-mesh nylon cloth was a latex having a polymerization rate of 93% and an average particle size of 0.35 μm. The particle size was measured with CAPA-500 (manufactured by Horiba, Ltd.).

(Production of oil-based ink)
10 g of dodecyl methacrylate / acrylic acid copolymer (copolymerization ratio: 98/2 mass ratio), 10 g of alkali blue and 71.30 g of shellsol are placed together with glass beads in a paint shaker (manufactured by Toyo Seiki Co., Ltd.) for 4 hours. As a result, a fine blue dispersion of alkali blue was obtained.
Blue oil-based ink was prepared by diluting 50 g of the resin particles (as solid content), 5 g of the blue dispersion (solid content) and 0.06 g of zirconium naphthenate into 1 liter of Isopar G.

(Preparation of lithographic printing plate by inkjet)
A hydrophilic substrate produced in Example 15 on a counter electrode with a 1.5 mm gap, with a modified Servo-Proter DA8400 manufactured by Graphtec Co., which can draw by PC output, with an ink ejection head attached to the pen-plotter part Was installed. Printing was carried out on the hydrophilic substrate using the produced oil-based ink. During plate making, the aluminum backing layer of the printing support and the counter electrode were electrically connected using a silver paste.
The plate-making plate was heated with a Ricoh fuser (manufactured by Ricoh Co., Ltd.) adjusted so that the plate surface temperature was 70 ° C. to fix the ink image. A drawing image of the obtained platemaking product was observed and evaluated with an optical microscope at a magnification of 200 times. In both cases, the images were clear with no blurring or missing of fine lines and fine characters.

(Print evaluation)
The obtained lithographic printing plate was attached to a cylinder of a printing machine SOR-M manufactured by Heidelberg. Dampening solution (EU-3 (Etch solution manufactured by Fuji Photo Film Co., Ltd.) / Water / isopropyl alcohol = 1/89/10 (volume ratio)) and TRANS-G (N) black ink (Dainippon Ink and Chemicals, Inc.) After supplying the fountain solution and the ink, printing was performed at a printing speed of 6000 sheets per hour. As a result, up to 5000 sheets were obtained with no non-image area stains.

Claims (13)

  A lithographic printing original plate comprising a hydrophilic polymer and a hydrophilic image-recording layer containing a hydrophilic polymer and a hydrophilic-hydrophobic conversion agent acting by applying thermal energy, and a support, the hydrophilic polymer comprising a main chain and a branched chain, A lithographic printing plate precursor wherein the branched chain contains a hydrophilic chain having a mass average molecular weight of 2 to 1,000,000.   The lithographic printing plate precursor according to claim 1, wherein the branched chain comprises a hydrophilic chain and a linking group, and the linking group is interposed between the hydrophilic chain and the main chain.   The lithographic printing plate precursor according to claim 2, wherein the linking group contains an ionic bond.   The lithographic printing plate precursor according to claim 1, wherein the main chain comprises two or more types of repeating units.   The lithographic printing plate precursor according to claim 4, wherein a branched chain is bonded to one type of repeating unit of the main chain, and no branched chain is bonded to another type of repeating unit of the main chain.   Claims in which the branched chain is composed of a hydrophilic chain and a linking group, the linking group is interposed between the hydrophilic chain and the main chain, and other types of repeating units of the main chain and the linking group have the same molecular structure Item 6. An original for lithographic printing according to Item 5.   The lithographic printing plate precursor according to claim 1, wherein the main chain has a mass average molecular weight of 1,000 to 2,000,000.   The lithographic printing plate precursor according to claim 1, wherein the main chain has a crosslinked structure.   The lithographic printing plate precursor according to claim 8, wherein the crosslinked structure contains an ionic bond.   A hydrophilic substrate comprising a hydrophilic layer containing a hydrophilic polymer and a support, wherein the hydrophilic polymer comprises a main chain and a branched chain, and the branched chain comprises a hydrophilic chain having a mass average molecular weight of 2 to 1,000,000 A hydrophilic substrate characterized by the above.   It consists of a hydrophilic image-recording layer containing a hydrophilic-hydrophobic conversion agent and a hydrophilic polymer acting by applying thermal energy, and a support. The hydrophilic polymer is composed of a main chain and branched chains, and the branched chain is 2 to 1,000,000. A lithographic printing plate precursor containing a hydrophilic chain having a weight average molecular weight of 2 is heated corresponding to the image, and a part of the hydrophilic image recording layer is converted into a hydrophobic region, so that a hydrophilic region and a hydrophobic region are formed on the surface. A lithographic printing method comprising: a step of making a lithographic printing plate comprising: a step of supplying a lithographic printing plate with dampening water and oil-based ink and printing.   A hydrophilic substrate comprising a hydrophilic layer containing a hydrophilic polymer and a support, the hydrophilic polymer comprising a main chain and a branched chain, and the hydrophilic substrate comprising a hydrophilic chain having a weight average molecular weight of 2 to 1,000,000 and a hydrophilic chain A part of the hydrophobic image recording layer is removed corresponding to the image from the lithographic printing original plate comprising the hydrophobic image recording layer provided on the layer, and the remaining hydrophilic region comprising the hydrophilic layer and the remaining hydrophobic layer A lithographic printing method comprising a step of making a lithographic printing plate having a hydrophobic region composed of a photosensitive image recording layer; and a step of supplying a lithographic printing plate with dampening water and oil-based ink and printing.   On a hydrophilic substrate comprising a hydrophilic layer comprising a hydrophilic polymer and a support, the hydrophilic polymer comprising a main chain and a branched chain, wherein the branched chain comprises a hydrophilic chain having a mass average molecular weight of 2 to 1,000,000 Applying a hydrophobic substance corresponding to the image, and making a lithographic printing plate having a hydrophilic region composed of the hydrophilic layer surface and a hydrophobic region to which the hydrophobic substance is attached; A lithographic printing method comprising a step of supplying water and oil-based ink for printing.