JP2006256025A - Image forming material, image forming method, and manufacturing method for image forming material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming material with printing resistance, which can record an image without the need for complicated image exposure via a film and which is excellent in sensitivity and resolution, a manufacturing method for the image forming material, and an image forming method wherein printing is done without wet processing after the recording of the image. <P>SOLUTION: The image forming material comprises an image forming layer, which is provided on a hydrophilic substrate, contains core/shell structure particulates which comprises a chemically active shell and a core with a softening point lower by 40°C than that of the chemically active shell, and a hydrophilic polymer. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an image forming method for an image forming material containing polymer fine particles (core / shell) particles in an image forming layer. In particular, the present invention relates to an image forming method of an image forming material capable of recording an image by scanning exposure of a laser beam based on a digital signal and developing the image by a printing machine.

  In general, a lithographic printing plate is composed of an oleophilic image portion that receives ink in the printing process and a hydrophilic non-image portion that receives dampening water. A conventional lithographic printing plate is made by performing mask exposure on a PS plate provided with a lipophilic photosensitive resin layer on a hydrophilic support through a film and then dissolving and removing a non-image portion with a developer. It was normal. In recent years, image information is electronically processed as digital information using a computer, stored, and output. Therefore, the image forming process corresponding to the digital image information is so-called image formation directly on the lithographic printing plate precursor without using a film by scanning exposure using active radiation having high directivity such as laser light. Computer-to-plate (CTP) will become the mainstream in the future.

  Further, in the conventional PS plate, a step (development process) for dissolving and removing the non-image portion after exposure is indispensable. Furthermore, a post-processing step of washing the developed printing plate with water, treating it with a rinsing liquid containing a surfactant, or treating with a desensitizing liquid containing gum arabic or starch derivatives is also necessary. The point that these additional wet treatments are indispensable is a big problem for the conventional PS plate.

  Even if the first half (image forming process) of the plate making process is simplified by the digital processing, the effect of the simplification is insufficient in the wet process where the second half (development process) is complicated. Particularly in recent years, consideration for the global environment has become a major concern for the entire industry. In consideration of the environment, it is desirable to simplify the wet post-treatment, change to a dry treatment, or eliminate the treatment.

  One method of eliminating the processing step is to mount the exposed printing plate precursor on the cylinder of the printing press, and supply dampening water and ink while rotating the cylinder, so that the non-image area of the printing plate precursor There is a method called on-press development that removes the toner. That is, after the exposure of the printing plate precursor, it is mounted on a printing machine as it is, and the processing is completed in a normal printing process. Such a lithographic printing plate precursor suitable for on-press development has a photosensitive layer soluble in dampening water or an ink solvent, and is suitable for development on a printing press placed in a bright room. It is necessary to have good light room handling. In the conventional PS plate, it is practically impossible to satisfy such a requirement.

Further, a lithographic printing original plate is described in which a photosensitive layer in which thermoplastic hydrophobic polymer fine particles are dispersed in a hydrophilic binder polymer is provided on a hydrophilic support. (For example, see Patent Document 1)
According to the description of Patent Document 1, in the plate making, after forming an image by infrared laser exposure and coalescence (fusion) of thermoplastic hydrophobic polymer fine particles by heat, the plate is mounted on the plate cylinder of the printing press. On-press development can be performed by supplying dampening water or ink. This lithographic printing plate precursor also has handleability in a bright room because the photosensitive region is in the infrared region.

However, in the image forming method in which the polymer particles are fused and coalesced by heat generated by exposure as described above, if the on-press development is facilitated, it is difficult to obtain the printing durability, and if the printing durability is increased, the on-press development is achieved. However, there is a problem that it is difficult to achieve both compatibility and deterioration of the stain resistance in printing.
Japanese Patent No. 2938397

  An object of the present invention is to provide an image forming material which can record an image without requiring image exposure through a complicated film, has printing durability, and is excellent in sensitivity and resolution, and a method for producing the same. There is. A second object is to provide an image forming method in which an image is recorded and then printed without performing wet development.

  The above object of the present invention is achieved by the following configurations.

(Claim 1)
An image having a chemically active shell, core / shell structure fine particles having a core having a chemically active shell and a softening point lower by 40 ° C. than the chemically active shell, and a hydrophilic polymer on a hydrophilic support. Forming material.

(Claim 2)
2. The image forming material according to claim 1, wherein the softening point of the shell is 20 degrees or more and the core is 60 degrees or more.

(Claim 3)
The image forming material according to claim 1 or 2 is heated in an image shape, the shell is softened to fuse the shells together and chemically bonded, and the image forming material is treated with an aqueous medium and heated. An image forming method, wherein an image is obtained through a step of removing a portion of the image forming layer that has not been formed.

(Claim 4)
3. An image forming method, wherein the image forming material according to claim 1 is scanned with a laser beam to be heated in an image form to obtain an image.

(Claim 5)
An image forming material according to claim 1 or 2, wherein the image forming material is produced.

  The image forming material, the image forming method, and the manufacturing method thereof according to the present invention can record an image without requiring image exposure through a complicated film, have printing durability, and have excellent effects on sensitivity and resolution. . Also, the image forming method according to the present invention has an excellent effect that it can be printed without performing wet development after recording an image.

The core / shell particle shell polymer preferably has a softening temperature of ˜180 ° C., more preferably a softening temperature of 80 to 120 ° C. The shell polymer also preferably has a softening temperature that is 40 ° C. or more higher than the softening temperature of the polymer forming the core fine particles. The core polymer preferably has a softening temperature of ˜120 ° C., more preferably has a softening temperature of 25 to 65 ° C.

  The average particle diameter of the core / shell structured fine particles is preferably 60 to 300 nm, and more preferably 80 to 250 nm. The particle size distribution is preferably as uniform as possible. The mass ratio of the core / shell is preferably 0.01 to 5, and more preferably 0.03 to 4. Two or more kinds of core / shell structured fine particles may be mixed and used. The core / shell structured fine particles are preferably contained in the image forming layer in an amount of 20 to 99% by mass, more preferably 50 to 95% by mass, and most preferably 60 to 90% by mass. preferable.

[Chemically active shell]
A chemically active substance is used for the fine particle shell. In imaging, the shell is chemically bonded to either another shell, a hydrophilic polymer and a hydrophilic support. The chemical bond is any one of a hydrogen bond, an ionic bond, a coordination bond, and a covalent bond. The chemical bond is preferably a bond formed without external energy (eg, thermal energy, light energy).

In the case of hydrogen bonding, the chemically active shell has one of a hydrogen (proton) donating group and a hydrogen accepting group, and either another shell, a hydrophilic polymer, or a hydrophilic support has the other. The chemically active shell may have both a hydrogen donating group and a hydrogen accepting group. Examples of the hydrogen donating group include a hydroxyl group (—OH), a carboxyl group (—COOH), a primary amino group (—NH ₂ ), a secondary amino group (—NRH), and an imino group (═NH). . Examples of the hydrogen-accepting group include a carbonyl group (> C═O), an ether group (—O—), and a tertiary amino group (—NR ₂ ). As a combination of a hydrogen donating group and a hydrogen accepting group, a hydroxyl group-tertiary amino group, a carboxyl group-tertiary amino group, and a hydroxyl group-ether group are preferable. More preferred are a hydroxyl group-tertiary amino group and a carboxyl group-tertiary amino group, most preferably a tertiary amino group in a phenolic hydroxyl group-nitrogen-containing heterocycle and a tertiary amino group in a carboxyl group-nitrogen-containing heterocycle. preferable.

  In the case of ionic bonding, the chemically active shell has one of an anionic group and a cationic group, and either another shell, a hydrophilic polymer or a hydrophilic support has the other. The chemically active shell may have both an anionic group and a cationic group. Examples of anionic groups include sulfonates, carboxylates and phosphonates. Examples of the cationic group include an ammonium group, an iodonium group, a sulfonium group, and a phosphonium group.

  In the case of coordination bonds, the chemically active shell has a functional group that functions as a ligand, the hydrophilic support is an aluminum support, and the functional group that functions as a ligand forms a complex with aluminum. It is preferable to do. Examples of functional groups that function as ligands include primary amino groups, secondary amino groups, tertiary amino groups, ammonium groups, pyridinium groups, phosphonic acid groups and salts thereof, boric acid groups and salts thereof, acetoacetyl groups , Phenolic hydroxyl groups, epoxy groups and siloxane groups. The functional group that functions as a ligand is preferably an ammonium group, a pyridinium group, a phosphonic acid group and a salt thereof, a boric acid group and a salt thereof, an acetoacetyl group, a phenolic hydroxyl group, an epoxy group, and a siloxane group, an ammonium group, More preferred are acetoacetyl groups, phenolic hydroxyl groups and epoxy groups.

  In the case of a covalent bond, the chemically active shell has one of the chemical reaction components described below as a functional group, and another shell, a hydrophilic polymer, or a hydrophilic support has the other as a functional group. The chemically active shell may have both groups.

(A) Reaction of active ester and group containing active hydrogen Examples of active ester include N-hydroxyphthalimide ester, N-hydroxysuccinimide ester, p-nitrophenyl ester, p-chlorophenyl ester, p-methoxycarbonyl Phenyl esters, p-sulfonium phenyl esters and HCH (OCH ₃ ) COOCH ₃ are included. Examples of groups containing active hydrogen include hydroxyl, primary amino group, secondary amino group, thiol, hydrazino, hydrazide and amide.

(B) Reaction between an acid anhydride and a group containing active hydrogen (C) Reaction between an acid halide and a group containing active hydrogen (D) Reaction seeking between a group leaving by a nucleophilic reaction and a nucleophilic group Examples of the group leaving by the nuclear reaction include a halogen atom, an alkylsulfonyloxy group, an arylsulfonyloxy group, and an azide group. Examples of nucleophilic groups include hydroxyl, amino, thiol, hydrazino, hydrazide, amide, sulfide and phosphino.

(E) Condensation reaction of a heterocyclic group having an unsaturated bond in the ring and a carbonyl group Examples of the heterocyclic ring having an unsaturated bond in the ring include N-alkylindole, N-alkylpyrrole, N-alkylimidazole (F) Condensation reaction between a heterocyclic group having an unsaturated bond in the ring and an acetal group (G) A phenol group having an active hydrogen at the ortho position and a hydroxymethyl group at the ortho or para position (H) Condensation reaction of a phenol group having an active hydrogen at the ortho position and an aniline group having a hydroxymethyl group at the ortho or para position (I) A carboxyl group and an N-methylol group Condensation reaction (J) Condensation reaction between carboxyl group and N-alkoxymethyl group (K) Condensation reaction between carboxyl group and carboxyl group (L) Condensation reaction between carboxyl group and group containing active hydrogen (M) Condensation reaction between group containing active hydrogen and N-methylol group (N) Condensation reaction between group containing active hydrogen and N-alkoxymethyl group (O) Condensation reaction between carbonyl group and hydrazide (P) Condensation reaction between primary amino, hydrazino, ketimine or ester and group containing active hydrogen atom (Q) Reaction between diazo group and active methylene group (R) Cyclic ether Examples of reactive cyclic ether groups of groups and nucleophilic groups include epoxy, oxetane and tetrahydrofuran. Examples of nucleophilic groups include hydroxyl, amino, carboxyl, thiol, hydrazino, hydrazide, amide, sulfide and phosphino.

(S) Reaction of vinyl ether with hydroxyl or carboxyl (T) Diels-Alder reaction of diene and dienophile (U) Michael addition reaction of enone with nucleophilic group Examples of enones include acryloyl and methacryloyl. Examples of nucleophilic groups include hydroxyl, amino, carboxyl, thiol, hydrazino, hydrazide, amide, sulfide and phosphino.

  (V) Reaction of isocyanate with group containing active hydrogen Examples of the group containing active hydrogen include hydroxyl, primary amino group, secondary amino group, thiol, hydrazino, hydrazide and amide.

The preferred reaction is
(A) reaction of an active ester with a group containing active hydrogen,
(D) a reaction between a group leaving by a nucleophilic reaction and a nucleophilic group,
(E) a condensation reaction between a heterocyclic group having an unsaturated bond in the ring and a carbonyl group,
(F) a condensation reaction between a heterocyclic group having an unsaturated bond in the ring and an acetal group,
(G) a condensation reaction between a phenol group having an active hydrogen at the ortho position and a phenol group having a hydroxymethyl group at the ortho or para position;
(H) a condensation reaction between a phenol group having an active hydrogen at the ortho position and an aniline group having a hydroxymethyl group at the ortho or para position;
(I) a condensation reaction between a carboxyl group and an N-methylol group,
(J) a condensation reaction between a carboxyl group and an N-alkoxymethyl group,
(M) a condensation reaction between a group containing active hydrogen and an N-methylol group,
(N) a condensation reaction between a group containing active hydrogen and an N-alkoxymethyl group,
(O) a condensation reaction between a carbonyl group and a hydrazide,
(Q) reaction of diazo group with active methylene group,
(R) a reaction between a cyclic ether group and a nucleophilic group,
(T) Diels-Alder reaction of diene and dienophile, and (V) Reaction of isocyanate with a group containing active hydrogen.

A more preferred reaction is
(A) reaction of an active ester with a group containing active hydrogen,
(D) a reaction between a group leaving by a nucleophilic reaction and a nucleophilic group,
(E) a condensation reaction between a heterocyclic group having an unsaturated bond in the ring and a carbonyl group,
(F) a condensation reaction between a heterocyclic group having an unsaturated bond in the ring and an acetal group,
(I) a condensation reaction between a carboxyl group and an N-methylol group,
(J) a condensation reaction between a carboxyl group and an N-alkoxymethyl group,
(M) a condensation reaction between a group containing active hydrogen and an N-methylol group,
(N) a condensation reaction between a group containing active hydrogen and an N-alkoxymethyl group,
(O) condensation reaction of carbonyl group and hydrazide, and (T) Diels-Alder reaction of diene and dienophile.

The most preferred reaction is
(A) reaction of an active ester with a group containing active hydrogen,
(I) a condensation reaction between a carboxyl group and an N-methylol group,
(J) a condensation reaction between a carboxyl group and an N-alkoxymethyl group,
(M) a condensation reaction between a group containing active hydrogen and an N-methylol group,
(N) a condensation reaction between a group containing active hydrogen and an N-alkoxymethyl group,
(O) condensation reaction of carbonyl group and hydrazide, and (T) Diels-Alder reaction of diene and dienophile.

  The shell is made of a compound having a chemically active functional group as described above. The shell is preferably a polymer having a chemically active functional group, and more preferably a polymer having a chemically active functional group in the side chain. The polymer main chain is preferably selected from hydrocarbons (polyolefins), polyesters, polyamides, polyimides, polyureas, polyurethanes, polyethers, and combinations thereof. A hydrocarbon backbone is particularly preferred. A chemically active functional group can be directly linked to the main chain. However, the chemically active functional group is preferably bonded to the main chain via a linking group.

The main chain of the polymer can have a substituent in addition to the chemically active functional group. Examples of the substituent include a halogen atom (F, Cl, Br, I), hydroxyl, carboxyl, sulfo, cyano, monovalent aliphatic group, monovalent aromatic group, monovalent heterocyclic group, —O -R, -CO-R, -NH-R, -N (-R) ₂ , -N ⁺ <(-R) ₃ , -CO-O-R, -O-CO-R, -CO-NH- R, —CO—N (—R) ₂ and —NH—CO—R are included.

  Each R is a monovalent aliphatic group, a monovalent aromatic group or a monovalent heterocyclic group. When the substituent includes a plurality of R, the plurality of R may be different from each other. Carboxyl and sulfo may have a hydrogen atom dissociated or may be in a salt state. A plurality of substituents of the main chain may be bonded to form an aliphatic ring or a heterocyclic ring. The ring formed may have a spiro bond relationship with the main chain. The formed ring may have a substituent. Examples of the substituent include oxo (═O) in addition to the substituent of the main chain. Further, a plurality of substituents of the main chain may be bonded to form a crosslinked structure.

The aliphatic group may have a cyclic structure or a branched structure. The aliphatic group may have an unsaturated bond. The aliphatic group has preferably 1 to 40 carbon atoms, more preferably 1 to 30 carbon atoms, still more preferably 1 to 20 carbon atoms, still more preferably 1 to 15 carbon atoms. Most preferably, it is from 12 to 12. The aliphatic group may have a substituent. Examples of the substituent of the aliphatic group include a halogen atom (F, Cl, Br, I), hydroxyl, carboxyl, sulfo, cyano, a monovalent aromatic group, a monovalent heterocyclic group, —O—R, -CO-R, -NH-R, -N (-R) ₂ , -N ⁺ <(-R) ₃ , -CO-O-R, -O-CO-R, -CO-NH-R,- CO-N (-R) 2 and -NH-CO-R are included. Each R is a monovalent aliphatic group, a monovalent aromatic group or a monovalent heterocyclic group. The carboxyl group and the sulfo group may be in a salt state even when the hydrogen atom is dissociated.

The aromatic group preferably has a benzene ring or a naphthalene ring. The aromatic group may have a substituent. Examples of substituents for aromatic groups include halogen atoms (F, Cl, Br, I), hydroxyl, carboxyl, sulfo, cyano, monovalent aliphatic groups, monovalent aromatic groups, monovalent heterocycles Group, —O—R, —CO—R, —NH—R, —N (—R) ₂ , —N ⁺ <(— R) ₃ , —CO—O—R, —O—CO—R, — CO—NH—R, —CO—N (—R) ₂ and —NH—CO—R are included. Each R is a monovalent aliphatic group, a monovalent aromatic group or a monovalent heterocyclic group. Carboxyl and sulfo may have a hydrogen atom dissociated or may be in a salt state. The heterocyclic group preferably has a 3- to 7-membered ring. The heterocyclic ring may have an unsaturated bond. Examples of the heterocyclic ring include a piperidine ring and a piperazine ring. The heterocyclic group may have a substituent. The substituent of the heterocyclic group is the same as the substituent of the aromatic group.

  When the polymer has a hydrocarbon main chain, the polymer preferably has a repeating unit containing a chemically active functional group represented by the following (I).

In the formula (I), R ¹ is a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, carboxyl, or an alkoxycarbonyl group having 2 to 11 carbon atoms. R ¹ is preferably a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, carboxyl, or an alkoxycarbonyl group having 2 to 7 carbon atoms, and preferably a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. More preferably, it is a carboxyl or an alkoxycarbonyl group having 2 to 4 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. preferable.

In the formula (I), L ¹ is a single bond or a divalent linking group. L ¹ is a divalent linking group composed of an aliphatic group, an aromatic group, a heterocyclic group, —O—, —S—, —CO—, —CS—, —NH—, and combinations thereof. Further preferred.

  Definitions and examples of the aliphatic group, aromatic group and heterocyclic group are as described above. In formula (I), X is a chemically active functional group.

  The core polymer preferably has a softening point of 60 to 150 ° C, and more preferably has a softening point of 80 to 130 ° C. The main chain of the core polymer is preferably selected from hydrocarbons (polyolefins), polyesters, polyamides, polyimides, polyureas, polyurethanes, polyethers, and combinations thereof. A hydrocarbon backbone is particularly preferred.

The main chain of the core polymer can have a substituent as long as the whole polymer is hydrophobic. Examples of the substituent include a halogen atom (F, Cl, Br, I), cyano, a monovalent aliphatic group, a monovalent aromatic group, a monovalent heterocyclic group, —O—R, —CO—. R, —NH—R, —N (—R) ₂ , —N ⁺ (—R) ₃ , —CO—O—R, —O—CO—R, —CO—NH—R, —CO—N ( -R) ₂ and -NH-CO-R are included. Each R is a monovalent aliphatic group, a monovalent aromatic group or a monovalent heterocyclic group. When the substituent includes a plurality of R, the plurality of R may be different from each other. The carboxyl, sulfo, sulfate ester group, phosphono and phosphate ester group may be in the form of a salt even if the hydrogen atom is dissociated. A plurality of substituents of the main chain may be bonded to form an aliphatic ring or a heterocyclic ring. The ring formed may have a spiro bond relationship with the main chain. The formed ring may have a substituent. Examples of the substituent include oxo (═O) in addition to the substituent of the main chain.

  When the core polymer has a hydrocarbon main chain, the core polymer preferably has a repeating unit represented by the following formula (II).

In the formula (II), R ² is a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, carboxyl, or an alkoxycarbonyl group having 2 to 11 carbon atoms. R ² is preferably a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, carboxyl, or an alkoxycarbonyl group having 2 to 7 carbon atoms, and preferably a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. More preferably, it is a carboxyl or an alkoxycarbonyl group having 2 to 4 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. preferable. In the formula (II), L ² is —O— or —N (—R ⁴ ) —. In the formula (II), R ³ and R ⁴ are each independently an aliphatic group, an aromatic group or a heterocyclic group. Definitions and examples of the aliphatic group, aromatic group, and heterocyclic group are as described in the fine particle core.

  Examples of the repeating unit of the core polymer are the same as the repeating units (101) to (140) and (201) to (252) described with reference to the core of the fine particles. As the core polymer, a copolymer composed of two or more kinds of repeating units can also be used. Examples of copolymers comprising two types of repeating units are shown below. The numbers in parentheses correspond to the example numbers of the repeating units described in the fine particle core. The ratio of the repeating unit is a molar ratio (%).

CP-101:-(102) ₇₀ --(110) _{30-
CP-102 :-( 102) 80 -} - (104) 20 -
CP-103:-(102) ₆₀ --(112) _40-
CP-104:-(102) ₉₅ --(140) _{5-
CP-105 :-( 102) 50 -} - (201) 50 -
CP-106:-(102) ₉₀ --(212) _{10-
CP-107 :-( 102) 80 -} - (207) 20 -
_{CP-108 :-( 201) 90 -} - (101) 10 -
_{CP-109 :-( 201) 80 -} - (104) 20 -
_{CP-110 :-( 201) 80 -} - (110) 20 -
_{CP-111 :-( 201) 90 -} - (112) 10 -
_{CP-112 :-( 201) 90 -} - (139) 10 -
CP-113:-(201) ₉₅ --(126) _{5-
CP-114 :-( 201) 80 -} - (204) 20 -
CP-115: − (201) ₈₀ − − (203) ₂₀ −
_{CP-116 :-( 201) 50 -} - (207) 50 -
_{CP-117 :-( 209) 80 -} - (104) 20 -
CP-118:-(209) ₇₀ --(106) _30-
CP-119:-(209) ₇₀ --(112) _{30-
CP-120 :-( 209) 80 -} - (207) 20 -
The core polymer can be synthesized by a polymerization reaction (radical polymerization reaction) of a monomer (generally, an ethylenically unsaturated monomer) corresponding to the above-described repeating unit. The core can be formed directly on the core microparticle by a polymerization reaction. In order to form homogeneous fine particles, it is preferable to use a surfactant in the core formation as in the core formation. Preferred surfactants are the same as the surfactants described in the core formation. Two or more kinds of surfactants may be used in combination.

  The amount of the surfactant used is preferably 0.01 to 10% by mass of the total amount of monomers. In the polymerization reaction, it is preferable to use a polymerization initiator (chain transfer agent). The amount of the polymerization initiator used is preferably 0.05 to 10% by mass of the total amount of monomers. The core polymer preferably has a softening temperature of 60 to 180 ° C., more preferably 70 to 140 ° C. The core polymer also preferably has a softening temperature lower than the softening temperature of the polymer forming the core fine particles.

1 base material As a base material, the well-known material used as a board | substrate of a printing plate can be used. For example, a metal plate, a plastic film, paper treated with a polyolefin, a composite base material obtained by appropriately bonding the above materials, and the like can be given. The thickness of the base material is not particularly limited as long as it can be attached to a printing press, but a thickness of 50 to 500 μm is generally easy to handle.

1.2 Non-metallic substrate: PET, etc. Examples of the plastic film include polyethylene terephthalate, polyethylene naphthalate, polyimide, polyamide, polycarbonate, polysulfone, polyphenylene oxide, and cellulose esters.

  As the substrate used in the present invention, polyethylene terephthalate and polyethylene naphthalate are particularly preferable. These plastic films are preferably subjected to easy adhesion treatment or undercoat layer coating on the coated surface in order to improve adhesion with the coated layer. Examples of the easy adhesion treatment include corona discharge treatment, flame treatment, plasma treatment, and ultraviolet irradiation treatment.

  Examples of the undercoat layer include a layer containing gelatin or latex. The undercoat layer may contain an organic or inorganic known conductive material.

In addition, for the purpose of controlling the slip property of the back surface (for example, reducing the friction coefficient with the plate cylinder surface), a substrate provided with a back surface coating layer can also be preferably used.
Using a batch type atmospheric pressure plasma processing apparatus (EC-I-H-340, manufactured by EC Chemical Co., Ltd.), the high frequency output is 4.5 kW, the frequency is 5 kHz, the processing time is 5 seconds, and the gas conditions are argon, Plasma treatment was performed at a volume ratio of nitrogen and hydrogen of 90% and 5%, respectively.

《Heat treatment conditions》
The support after slitting to a width of 1.25 m was subjected to low tension heat treatment at 180 ° C. for 1 minute at a tension of 2 hPa.

<Preparation of printing plate material>
Immediately before the hydrophilic layer was applied, the undercoated support 1 was dried by applying a heat treatment at 100 ° C. for 30 seconds, and covered with a moisture-proof sheet so as not to enter the humidity in the air. When a moisture content was measured by sampling a part of the support sample, the support 1 was 0.2%. About the thing with the cover, it apply | coated immediately after removing the sheet | seat.

1.3 Metal Substrate: AL Grain etc. Examples of the metal plate include iron, stainless steel, aluminum and the like, and aluminum is particularly preferable from the relationship between specific gravity and rigidity. The aluminum plate is usually used after degreasing with an alkali, an acid, a solvent or the like in order to remove oil used during rolling and winding existing on the surface. As the degreasing treatment, degreasing with an alkaline aqueous solution is particularly preferable. Moreover, in order to improve adhesiveness with a coating layer, it is preferable to perform an easy adhesion process or undercoat layer application | coating to an application surface.

  For example, a method of dipping in a liquid containing a coupling agent such as a silicate or a silane coupling agent or applying a liquid, followed by sufficient drying can be used. Anodizing treatment is also considered as a kind of easy adhesion treatment and can be used. Moreover, it can also use combining an anodizing process and the said immersion or application | coating process. Moreover, the aluminum base material roughened by the well-known method, what is called an aluminum grain can also be used as a base material which has a hydrophilic surface.

  1.3.2 Details of aluminum grain will be described.

The aluminum support used for the lithographic printing plate support of the present invention includes a support made of pure aluminum and an aluminum alloy. Various aluminum alloys can be used. For example, an alloy of a metal such as silicon, copper, manganese, magnesium, chromium, zinc, lead, bismuth, nickel, titanium, sodium, iron, and aluminum is used.
The aluminum support is preferably subjected to a degreasing treatment in order to remove the rolling oil on the aluminum surface prior to roughening.

  As the degreasing treatment, a degreasing treatment using a solvent such as trichlene or thinner, an emulsion degreasing treatment using an emulsion such as kesilon or triethanol, or the like is used. In addition, an alkaline aqueous solution such as caustic soda can be used for the degreasing treatment. When an alkaline aqueous solution such as caustic soda is used for the degreasing treatment, dirt and oxide film that cannot be removed only by the degreasing treatment can be removed.

  When an alkaline aqueous solution such as caustic soda is used for the degreasing treatment, it is preferable to carry out a neutralization treatment by immersing in an acid such as phosphoric acid, nitric acid, hydrochloric acid, sulfuric acid, chromic acid or a mixed acid thereof. When electrochemical roughening is performed after the neutralization treatment, it is particularly preferable to match the acid used for neutralization with the acid used for electrochemical roughening.

  As roughening of the support, electrolytic surface roughening is carried out by the method of the present invention. As a pretreatment, a rough surface appropriately combined with chemical roughening and mechanical roughening with an appropriate amount of treatment. It does not matter if it is made.

Chemical roughening uses an aqueous solution of alkali such as caustic soda as in the degreasing treatment. After the treatment, it is preferable to carry out a neutralization treatment by dipping in an acid such as phosphoric acid, nitric acid, hydrochloric acid, sulfuric acid, chromic acid, or a mixed acid thereof. When electrochemical roughening is performed after the neutralization treatment, it is particularly preferable to match the acid used for neutralization with the acid used for electrochemical roughening.
The mechanical roughening method is not particularly limited, but brush polishing and honing polishing are preferable.
In brush polishing, for example, a cylindrical brush with bristles having a bristle diameter of 0.2 to 1 mm is rotated, and while a slurry in which abrasive is dispersed in water is supplied to the contact surface, it is pressed against the surface of the support to give a rough surface. To do.

In the honing polishing, a slurry in which an abrasive is dispersed in water is injected by applying pressure from a nozzle, and the surface is roughened by colliding with the support surface obliquely.
Examples of the abrasive include those generally used for polishing such as volcanic ash, alumina, silicon carbide and the like, and the particle size thereof is # 200 to # 2000, preferably # 400 to # 800.
A mechanically roughened support is immersed in an aqueous solution of acid or alkali to remove abrasives, aluminum scraps, etc. that have digged into the surface of the support, or to control the pit shape. Etching is preferred. Examples of the acid include sulfuric acid, persulfuric acid, hydrofluoric acid, phosphoric acid, nitric acid, and hydrochloric acid. Examples of the base include sodium hydroxide and potassium hydroxide. Among these, it is preferable to use an alkaline aqueous solution.
When the above is immersed in an alkaline aqueous solution, it is preferably immersed in an acid such as phosphoric acid, nitric acid, sulfuric acid, chromic acid, or a mixed acid thereof for neutralization.
When the electrochemical roughening is performed after the neutralization treatment, it is particularly preferable that the acid used for the neutralization is matched with the acid used for the electrochemical roughening. When the oxidation treatment is performed, it is particularly preferable to match the acid used for neutralization with the acid used for the anodization treatment.

  Electrochemical roughening is generally performed using an alternating current in an acidic electrolyte. As the acidic electrolyte, those usually used for electrochemical surface roughening can be used, but it is preferable to use a hydrochloric acid-based or nitric acid-based electrolytic solution, and a hydrochloric acid-based electrolytic solution is used for the divided electrolytic treatment in the present invention. Is particularly preferred.

Various waveforms such as a rectangular wave, a trapezoidal wave, and a sawtooth wave can be used as the power supply waveform used for electrolysis, and a sine wave is particularly preferable.
1-50V is preferable and the voltage applied in the electrochemical roughening using nitric acid type electrolyte solution has more preferable 5-30V. The current density (peak value) is preferably from 10 to 200 A / dm ^2, more preferably 20 to 150 A / dm ^2.

Quantity of electricity by summing all the processing steps, 100~2000C / dm ^2, preferably not 200~1500C / dm ^2, more preferably a 200~1000C / dm ^2.

  The temperature is preferably 10 to 50 ° C, more preferably 15 to 45 ° C. The concentration of nitric acid is preferably 0.1 to 5% by mass.

  If necessary, nitrates, chlorides, amines, aldehydes, phosphoric acid, chromic acid, boric acid, acetic acid, oxalic acid, and the like can be added to the electrolytic solution.

1-50V is preferable and the voltage applied in the electrochemical roughening using hydrochloric acid type electrolyte solution has more preferable 5-30V. The current density (peak value) is preferably from 10 to 200 A / dm ^2, more preferably 20 to 150 A / dm ^2. The total amount of electricity is preferably 100 to 2000 C / dm ^2, more preferably 200 to 1000 C / dm ² . The temperature is preferably 10 to 50 ° C, more preferably 15 to 45 ° C. The hydrochloric acid concentration is preferably 0.1 to 5% by mass.

If necessary, nitrates, chlorides, amines, aldehydes, phosphoric acid, chromic acid, boric acid, acetic acid, oxalic acid, and the like can be added to the electrolytic solution.
In addition, a method for performing electrochemical roughening by dividing into multiple times as described in JP-A-10-869 can be preferably used.
The electrochemically roughened support is preferably immersed in an acid or alkali aqueous solution to etch the surface in order to remove surface smut or the like or to control the pit shape.

  Examples of the acid include sulfuric acid, persulfuric acid, hydrofluoric acid, phosphoric acid, nitric acid, hydrochloric acid and the like, and examples of the base include sodium hydroxide and potassium hydroxide. Among these, it is preferable to use an alkaline aqueous solution. When the above is immersed in an alkaline aqueous solution, it is preferably immersed in an acid such as phosphoric acid, nitric acid, sulfuric acid, chromic acid, or a mixed acid thereof for neutralization. When the anodizing treatment is performed after the neutralizing treatment, it is particularly preferable that the acid used for the neutralization is matched with the acid used for the anodizing treatment.

Following the roughening treatment, an anodizing treatment is performed, followed by a sealing treatment and a hydrophilization treatment.
There is no restriction | limiting in particular in the method of the anodizing process used by this invention, A well-known method can be used. An oxide film is formed on the support by anodization. In the present invention, a method of electrolyzing with an aqueous solution containing sulfuric acid and / or phosphoric acid or the like at a concentration of 10 to 50% as an electrolytic solution at an electric current density of 1 to 10 A / dm ² is preferably used for the anodizing treatment. US Pat. No. 1,412,768 describes a method of electrolysis at a high current density in sulfuric acid, and a method of electrolysis using phosphoric acid described in US Pat. No. 3,511,661. Can be used.

  The anodized support may be sealed as necessary. These sealing treatments can be carried out using known methods such as hot water treatment, boiling water treatment, steam treatment, sodium silicate treatment, dichromate aqueous solution treatment, nitrite treatment, ammonium acetate treatment.

1.3.3 Example: Hydrochloric Acid Electrolytic Grain A 0.24 mm thick aluminum plate (material 1050, tempered H16) was immersed in a 1% by mass aqueous sodium hydroxide solution at 50 ° C., and the dissolution amount was 2 g / The solution was dissolved so as to be m ² and washed with water, then immersed in a 0.1 mass% hydrochloric acid aqueous solution at 25 ° C. for 30 seconds, neutralized, and then washed with water.

Next, this aluminum plate was subjected to an electrolytic surface roughening treatment with an electrolytic solution containing hydrochloric acid 10 g / L and aluminum 0.5 g / L using a sine wave alternating current and a peak current density of 50 A / dm ^2. It was. The distance between the electrode and the sample surface at this time was 10 mm. Perform electrolytic graining treatment is divided into 12 times, and the quantity of electricity used in one treatment (at a positive polarity) as the 40C / dm ^2, treatment quantity of electricity 480C / dm ² in total (at a positive polarity).

  In addition, a rest period of 5 seconds was provided between each surface roughening treatment.

After electrolytic surface roughening, it is immersed in a 1% by weight sodium hydroxide aqueous solution maintained at 50 ° C. and etched so that the amount of dissolution including the smut of the roughened surface becomes 1.2 g / m ^2. Then, it was washed with water, then immersed in a 10% aqueous sulfuric acid solution maintained at 25 ° C. for 10 seconds, neutralized, and then washed with water. Next, anodization was performed in a 20% sulfuric acid aqueous solution so that the amount of electricity was 150 C / dm ² under a constant voltage condition of 20 V, followed by washing with water.

  Next, after squeezing the surface water after washing with water, it was immersed in a 1% by mass sodium dihydrogen phosphate aqueous solution maintained at 70 ° C. for 30 seconds, washed with water, dried at 80 ° C. for 5 minutes, Got. Ra of the substrate 1 was 460 nm (measured at 40 times using RST Plus manufactured by WYKO).

2 Hydrophilic layer (same for anchor layer)
2.1 Inorganic binder As a hydrophilic material used for a hydrophilic layer, a metal oxide is preferable.

  The metal oxide preferably contains metal oxide fine particles. Examples thereof include colloidal silica, alumina sol, titania sol, and other metal oxide sols. The form of the metal oxide fine particles may be spherical, needle-like, feather-like, or any other form. The average particle diameter is preferably 3 to 100 nm, and several kinds of metal oxide fine particles having different average particle diameters can be used in combination. The surface of the particles may be surface treated.

The metal oxide fine particles can be used as a binder by utilizing the film forming property. The decrease in hydrophilicity is less than when an organic binder is used, and it is suitable for use in a hydrophilic layer.
Among the above, colloidal silica can be preferably used in the present invention. Colloidal silica has the advantage of high film-forming properties even under relatively low temperature drying conditions, and good strength can be obtained even in a layer in which the material containing no carbon atom is 91% by mass or more.

  The colloidal silica preferably includes necklace-like colloidal silica, which will be described later, and fine particle colloidal silica having an average particle size of 20 nm or less, and the colloidal silica preferably exhibits alkalinity as a colloidal solution.

  The necklace-like colloidal silica used in the present invention is a general term for an aqueous dispersion of spherical silica whose primary particle diameter is on the order of nm. The necklace-like colloidal silica used in the present invention means “pearl necklace-like” colloidal silica in which spherical colloidal silica having a primary particle diameter of 10 to 50 nm is bonded to a length of 50 to 400 nm. The pearl necklace shape (that is, the pearl necklace shape) means that the image in a state in which the silica particles of colloidal silica are connected and connected has a shape like a pearl necklace. The bond between the silica particles constituting the necklace-shaped colloidal silica is presumed to be —Si—O—Si— in which —SiOH groups present on the surface of the silica particles are dehydrated. Specific examples of the colloidal silica in the form of necklace include “Snowtex-PS” series manufactured by Nissan Chemical Industries, Ltd.

Product names include “Snowtex-PS-S (average particle size in the connected state is about 110 nm)”, “Snowtex-PS-M (average particle size in the connected state is about 120 nm)” and “Snowtex- PS-L (the average particle size in the connected state is about 170 nm) ", and acidic products corresponding to these are" Snowtex-PS-SO "," Snowtex-PS-MO "and “Snowtex-PS-LO”.
By adding necklace-like colloidal silica, it becomes possible to maintain the strength while ensuring the porosity of the layer, and it can be preferably used as a porous material for the layer.

  Among these, when “Snowtex PS-S”, “Snowtex PS-M”, and “Snowtex PS-L”, which are alkaline, are used, the strength of the hydrophilic layer is improved and the number of printed sheets is large. However, it is particularly preferable because the occurrence of soiling is suppressed.

  Further, it is known that the colloidal silica has a stronger binding force as the particle diameter is smaller, and it is preferable to use colloidal silica having an average particle diameter of 20 nm or less in the present invention, and more preferably 3 to 15 nm. preferable. In addition, as described above, alkaline colloidal silica is particularly preferable because alkaline colloidal silica has a high effect of suppressing the occurrence of soiling.

Alkaline colloidal silica having an average particle size within this range includes “Snowtex-20 (particle size 10-20 nm)”, “Snowtex-30 (particle size 10-20 nm)”, “Snowtex” manufactured by Nissan Chemical Co., Ltd. -40 (particle diameter 10-20 nm) "," Snowtex-N (particle diameter 10-20 nm) "," Snowtex-S (particle diameter 8-11 nm) "," Snowtex-XS (particle diameter 4-6 nm) ) ".
Colloidal silica having an average particle size of 20 nm or less is particularly preferable because it can be further improved in strength while maintaining the porous property of the layer when used in combination with the aforementioned necklace-like colloidal silica.

  The ratio of colloidal silica / necklace-shaped colloidal silica having an average particle diameter of 20 nm or less is preferably 95/5 to 5/95, more preferably 70/30 to 20/80, and still more preferably 60/40 to 30/70.

A silicate aqueous solution can also be used as another additive material in the hydrophilic layer of the present invention. Alkali metal silicates such as silicate Na, silicate K, and silicate Li are preferred, and the SiO ₂ / M ₂ O ratio is in a range where the pH of the entire coating solution does not exceed 13 when silicate is added. It is preferable to select such that the inorganic particles are not dissolved.

2.2 Organic / Inorganic Binder An inorganic polymer or an organic-inorganic hybrid polymer using a metal alkoxide by a so-called sol-gel method can also be used. The formation of an inorganic polymer or an organic-inorganic hybrid polymer by the sol-gel method is described in, for example, “Application of the sol-gel method” (Sakuo Sakuo / Published by Agne Jofusha) or cited in this book. Known methods described in the published literature can be used.

2.3 Organic Binder A hydrophilic organic resin may be contained in the hydrophilic layer.

  Examples of the hydrophilic organic resin include polyethylene oxide, polypropylene oxide, polyvinyl alcohol, polyethylene glycol (PEG), polyvinyl ether, styrene-butadiene copolymer, conjugated diene polymer latex of methyl methacrylate-butadiene copolymer, and acrylic. Examples thereof include resins such as polymer latex, vinyl polymer latex, polyacrylamide, and polyvinylpyrrolidone.

  In addition, the resin may contain a cationic resin. Examples of the cationic resin include polyalkylene polyamines such as polyethylene amine and polypropylene polyamine or derivatives thereof, and acrylic resins having a tertiary amino group or a quaternary ammonium group. , Diacrylamine and the like. The cationic resin may be added in the form of fine particles. Examples thereof include a cationic microgel described in JP-A-6-161101.

  As a more preferred embodiment of the present invention, the hydrophilic organic resin contained in the hydrophilic layer is water-soluble, and at least part of the hydrophilic organic resin remains in a water-soluble state and exists in a state that can be eluted in water. Can be mentioned. Even if it is a water-soluble material, when it is cross-linked by a cross-linking agent or the like and becomes insoluble in water, there is a concern that its hydrophilicity is lowered and print performance is deteriorated.

As the water-soluble material contained in the hydrophilic layer of the present invention, saccharides are preferable. By including saccharides in the hydrophilic layer, an effect of improving the resolution of image formation or improving printing durability can be obtained in combination with a functional layer having an image forming ability described later.
As the saccharide, an oligosaccharide, which will be described in detail later, can be used, but it is particularly preferable to use a polysaccharide.

  As polysaccharides, starches, celluloses, polyuronic acids, pullulans and the like can be used, but cellulose derivatives such as methyl cellulose salts, carboxymethyl cellulose salts, hydroxyethyl cellulose salts are particularly preferable, and sodium salts and ammonium salts of carboxymethyl cellulose are preferable. More preferred.

  This is because an effect of forming the surface shape of the hydrophilic layer in a preferable state can be obtained by including the polysaccharide in the hydrophilic layer.

  The surface of the hydrophilic layer preferably has a concavo-convex structure with a pitch of 0.1 to 50 μm like the aluminum grain of the PS plate, and this concavo-convex improves water retention and image area retention.

  Such a concavo-convex structure can be formed by containing an appropriate amount of a filler having an appropriate particle size in the hydrophilic layer, but the above-mentioned alkaline colloidal silica and the above-mentioned water-soluble substance are used in the hydrophilic layer coating solution. It is preferable that a structure having better printing performance can be obtained by containing a polysaccharide and forming a phase separation when the hydrophilic layer is applied and dried.

  The shape of the concavo-convex structure (such as pitch and surface roughness) is the type and amount of alkaline colloidal silica, the type and amount of water-soluble polysaccharides, the type and amount of other additives, the solid content concentration of the coating solution, and the wet film. The thickness and drying conditions can be appropriately controlled.

The pitch of the concavo-convex structure is more preferably 0.2 to 30 μm, and further preferably 0.5 to 20 μm. Further, a concavo-convex structure having a multiple structure in which a concavo-convex structure having a smaller pitch is formed on the concavo-convex structure having a large pitch may be formed.
As surface roughness, 100-1000 nm is preferable by Ra, and 150-600 nm is more preferable.

  Moreover, as a film thickness of a hydrophilic layer, it is 0.01-50 micrometers, Preferably it is 0.2-10 micrometers, More preferably, it is 0.5-3 micrometers.

2.4 Fillers / Porous Silica Porous silica or porous aluminosilicate particles Porous silica particles are generally produced by a wet method or a dry method. In the wet method, it can be obtained by drying and pulverizing a gel obtained by neutralizing an aqueous silicate solution, or by pulverizing a precipitate deposited after neutralization. In the dry method, silicon tetrachloride is burned together with hydrogen and oxygen to obtain silica. These particles can be controlled in porosity and particle size by adjusting the production conditions.

As the porous silica particles, those obtained from a wet gel are particularly preferable.
The porous aluminosilicate particles are produced, for example, by the method described in JP-A-10-71764. That is, amorphous composite particles synthesized by hydrolysis using aluminum alkoxide and silicon alkoxide as main components. The ratio of alumina to silica in the particles can be synthesized in the range of 1: 4 to 4: 1. In addition, those produced as composite particles of three or more components by adding an alkoxide of another metal during production can also be used in the present invention. These composite particles can also control the porosity and particle size by adjusting the production conditions.

  The porosity of the particles is preferably 1.0 ml / g or more in terms of pore volume before dispersion, more preferably 1.2 ml / g or more, and 1.8 to 2.5 ml / g. More preferably, it is as follows.

The pore volume is closely related to the water retention of the coating film. The larger the pore volume, the better the water retention and the less smudged during printing, and the greater the water volume latitude, but greater than 2.5 ml / g. Then, since the particles themselves become very brittle, the durability of the coating film decreases. When the pore volume is less than 1.0 ml / g, it is difficult to stain during printing and the water amount latitude is insufficient.
The particle size is preferably substantially 1 μm or less, and more preferably 0.5 μm or less, in a state where it is contained in the hydrophilic layer (including when crushed during dispersion, for example). If unnecessarily coarse particles are present, porous and steep protrusions are formed on the surface of the hydrophilic layer, and ink tends to remain around the protrusions, which may deteriorate non-image area stains and blanket stains.
-Zeolite particles Zeolite is a crystalline aluminosilicate, which is a porous body having regular three-dimensional network voids with a pore diameter of 0.3 to 1 nm. The general formula combining natural and synthetic zeolite is expressed as follows:

(M ₁ , M ₂ ^1/2 ) m (AlmSinO ₂ (m + n)) · xH ₂ O
Here, M ₁ and M ₂ are exchangeable cations, and M ₁ is Li ⁺ , Na ⁺ , K ⁺ , Tl ⁺ , Me ₄ N ⁺ (TMA), Et ₄ N ⁺ (TEA), Pr ₄ N ⁺ (TPA), C ₇ H ₁₅ N ₂ ⁺ , C ₈ H ₁₆ N ⁺ etc., and M ₂ is Ca ²⁺ , Mg ²⁺ , Ba ²⁺ , Sr ²⁺ , C ₈ H ₁₈ N ²²⁺ etc. It is. Further, n ≧ m, and the value of m / n, that is, the Al / Si ratio is 1 or less. The higher the Al / Si ratio, the greater the amount of exchangeable cations, and thus the higher the polarity and therefore the higher the hydrophilicity. A preferable Al / Si ratio is 0.4 to 1.0, and more preferably 0.8 to 1.0. x represents an integer.

The zeolite particles used in the present invention are preferably synthetic zeolite having a stable Al / Si ratio and a relatively sharp particle size distribution. For example, zeolite A: Na ₁₂ (Al ₁₂ Si ₁₂ O ₄₈ ). 27H ₂ O; Al / Si ratio 1.0, zeolite _{X: Na86 (Al 86 Si 106} O 384) · 264H 2 O; Al / Si ratio 0.811, zeolite _{Y: Na56 (Al 56 Si 136} O 384) · 250H ₂ O; Al / Si ratio 0.412 and the like.

By containing highly hydrophilic porous particles having an Al / Si ratio of 0.4 to 1.0, the hydrophilicity of the hydrophilic layer itself is greatly improved, it is difficult to get dirty during printing, and the water latitude is widened. In addition, the dirt on the fingerprint marks is greatly improved. When the Al / Si ratio is less than 0.4, the hydrophilicity is insufficient, and the effect of improving the performance becomes small.
The particle diameter of the porous inorganic particles is preferably substantially 1 μm or less, and more preferably 0.5 μm or less, when contained in the hydrophilic layer.

  In addition, the hydrophilic layer of the printing plate material of the present invention may contain layered clay mineral particles as a metal oxide. Examples of the layered mineral particles include kaolinite, halloysite, talc, smectite (montmorillonite, beidellite, hectorite, sabonite, etc.), clay minerals such as vermiculite, mica (mica), chlorite, hydrotalcite, layered polysilicate ( Kanemite, macatite, ialite, magadiite, kenyaite, etc.).

  Among them, it is considered that the higher the charge density of the unit layer (unit layer), the higher the polarity and the higher the hydrophilicity. The charge density is preferably 0.25 or more, more preferably 0.6 or more. Examples of the layered mineral having such a charge density include smectite (charge density 0.25 to 0.6; negative charge), vermiculite (charge density 0.6 to 0.9; negative charge) and the like. In particular, synthetic fluoromica is preferable because it can be obtained with stable quality such as particle size. Among the synthetic fluorine mica, those that are swellable are preferable, and those that are free swell are more preferable.

Also used are intercalation compounds of the above-mentioned layered minerals (pillar crystals, etc.), those subjected to ion exchange treatment, and those subjected to surface treatment (silane coupling treatment, compounding treatment with organic binder, etc.) can do.
The size of the flat lamellar mineral particles is 20 μm or less in average particle diameter (maximum particle length) in the state of being contained in the layer (including the case where the swelling process and dispersion peeling process have been performed). The average aspect ratio (maximum particle length / particle thickness) is preferably a thin layer of 20 or more, the average particle size is 5 μm or less, the average aspect ratio is more preferably 50 or more, and the average particle size More preferably, the diameter is 1 μm or less and the average aspect ratio is 50 or more.

  When the particle size is in the above range, the continuity and flexibility in the planar direction, which are the characteristics of the thin layered particles, are imparted to the coating film, and it is difficult for cracks to occur, and a tough coating film can be obtained in a dry state. Moreover, in the coating liquid containing many particulate matters, sedimentation of particulate matter can be suppressed by the thickening effect of the layered clay mineral. If the particle diameter is out of the above range, the effect of suppressing scratches due to scratching may be reduced. Further, when the aspect ratio is less than the above range, the flexibility becomes insufficient, and the effect of suppressing scratches due to scratching may also be reduced.

  The content of the layered mineral particles is preferably 0.1 to 30% by mass, and more preferably 1 to 10% by mass based on the entire layer.

  In particular, swellable synthetic fluorinated mica and smectite are preferable because they are effective even when added in a small amount. The layered mineral particles may be added as a powder to the coating solution, but in order to obtain a good degree of dispersion even with a simple preparation method (no need for a dispersion step such as media dispersion), the layered mineral particles are used alone. After the gel swollen in water is prepared, it is preferably added to the coating solution.

2.5 Other materials that can be contained In addition, the hydrophilic layer (coating solution) of the present invention may contain a water-soluble surfactant for the purpose of improving coating properties. A surfactant such as Si-based or F-based can be used, but it is particularly preferable to use a surfactant containing Si element because there is no fear of causing printing stains. The content of the surfactant is preferably 0.01 to 3% by mass, more preferably 0.03 to 1% by mass, based on the entire hydrophilic layer (solid content as the coating solution).

  In addition, the hydrophilic layer of the present invention can contain a phosphate. In the present invention, since the hydrophilic layer coating solution is preferably alkaline, the phosphate is preferably added as trisodium phosphate or disodium hydrogen phosphate. By adding phosphate, the effect of improving the mesh opening at the time of printing can be obtained. The addition amount of phosphate is preferably 0.1 to 5% by mass, and more preferably 0.5 to 2% by mass as an effective amount excluding hydrate.

3 Image Forming Layer 3.1 Hydrophobized Precursor Fine Particle As one preferred embodiment of the image forming layer of the present invention, an embodiment in which the image forming layer contains a hydrophobized precursor can be mentioned.

As the hydrophobizing precursor, a polymer that changes from hydrophilicity (water-soluble or water-swellable) to hydrophobicity by heat can be used. Specific examples include polymers containing aryl diazosulfonate units disclosed in JP-A-2000-56449.
However, in the present invention, it is preferable to use thermoplastic hydrophobic particles or microcapsules enclosing a hydrophobic substance as the hydrophobizing precursor.

  Examples of the thermoplastic fine particles include heat-fusible fine particles and heat-fusible fine particles described later.

  The heat-meltable fine particles used in the present invention are fine particles formed of a material that has a low viscosity when melted, and is generally classified as a wax, among thermoplastic materials. The physical properties are preferably a softening point of 40 ° C. or higher and 120 ° C. or lower, a melting point of 60 ° C. or higher and 150 ° C. or lower, more preferably a softening point of 40 ° C. or higher and 100 ° C. or lower, and a melting point of 60 ° C. or higher and 120 ° C. or lower. When the melting point is less than 60 ° C., storage stability is a problem, and when the melting point is higher than 300 ° C., ink deposition sensitivity is lowered.

Usable materials include paraffin, polyolefin, polyethylene wax, microcrystalline wax, fatty acid wax and the like. These have a molecular weight of about 800 to 10,000. In order to facilitate emulsification, these waxes can be oxidized to introduce polar groups such as hydroxyl groups, ester groups, carboxyl groups, aldehyde groups, and peroxide groups. Furthermore, in order to lower the softening point and improve the workability, these waxes are stearamide, linolenamide, laurylamide, myristamide, hardened beef fatty acid amide, palmitoamide, oleic acid amide, rice sugar fatty acid amide, coconut fatty acid amide. Alternatively, methylolated products of these fatty acid amides, methylene bisstellaramide, ethylene bisstellaramide, and the like can be added. Coumarone-indene resin, rosin-modified phenol resin, terpene-modified phenol resin, xylene resin, ketone resin, acrylic resin, ionomer, and copolymers of these resins can also be used.
Among these, it is preferable to contain any of polyethylene, microcrystalline, fatty acid ester, and fatty acid. Since these materials have a relatively low melting point and a low melt viscosity, high-sensitivity image formation can be performed.

In addition, since these materials have lubricity, damage when a shearing force is applied to the surface of the printing plate material is reduced, and resistance to printing stains due to scratches or the like is improved.
The heat-meltable fine particles are preferably dispersible in water, and the average particle size is preferably 0.01 to 10 μm, more preferably 0.1 to 3 μm. When the average particle size is smaller than 0.01 μm, when the coating liquid for the layer containing the heat-meltable fine particles is applied onto the porous hydrophilic layer described later, the heat-meltable fine particles are not removed from the pores of the hydrophilic layer. It becomes easy to enter inside or into the gaps between fine irregularities on the surface of the hydrophilic layer, and the on-press development becomes insufficient, which may cause scumming. When the average particle size of the heat-meltable fine particles is larger than 10 μm, the resolution is lowered.

Further, the composition of the heat-meltable fine particles may vary continuously between the inside and the surface layer, or may be coated with a different material.
As a coating method, a known microcapsule formation method, a sol-gel method, or the like can be used.
As content of the heat-meltable microparticles | fine-particles in a layer, 1-90 mass% of the whole layer is preferable, and 5-80 mass% is more preferable.

  Examples of the heat-fusible fine particles of the present invention include thermoplastic hydrophobic polymer fine particles, and there is no specific upper limit for the softening temperature of the polymer fine particles, but the temperature is the decomposition temperature of the polymer fine particles. Lower is preferred. The weight average molecular weight (Mw) of the polymer is preferably in the range of 10,000 to 1,000,000.

  Specific examples of the polymer constituting the polymer particles include, for example, diene (co) polymers such as polypropylene, polybutadiene, polyisoprene and ethylene-butadiene copolymer, styrene-butadiene copolymer, Synthetic rubbers such as methyl methacrylate-butadiene copolymer, acrylonitrile-butadiene copolymer, polymethyl methacrylate, methyl methacrylate- (2-ethylhexyl acrylate) copolymer, methyl methacrylate-methacrylic acid copolymer, methyl acrylate- ( N-methylolacrylamide) copolymer, (meth) acrylic acid ester such as polyacrylonitrile, (meth) acrylic acid (co) polymer, polyvinyl acetate, vinyl acetate-vinyl propionate copolymer, vinyl acetate-ethylene copolymer Vinyl etc. of polymers Ester (co) polymer, vinyl acetate - (2-ethylhexyl acrylate) copolymers, polyvinyl chloride, polyvinylidene chloride, polystyrene and copolymers thereof. Of these, (meth) acrylic acid esters, (meth) acrylic acid (co) polymers, vinyl ester (co) polymers, polystyrene, and synthetic rubbers are preferably used.

  The polymer polymer fine particles may be composed of a polymer polymer polymerized by any known method such as emulsion polymerization, suspension polymerization, solution polymerization, and gas phase polymerization. As a method of microparticulating a polymer polymer polymerized by a solution polymerization method or a gas phase polymerization method, a method of spraying a solution in an organic solvent of the polymer polymer into an inert gas and drying to form particles, Examples thereof include a method in which a high molecular weight polymer is dissolved in a water-immiscible organic solvent, this solution is dispersed in water or an aqueous medium, and the organic solvent is distilled off to form fine particles.

In any of the methods, a surfactant, such as sodium lauryl sulfate, sodium dodecylbenzenesulfonate, polyethylene glycol, or a water-soluble resin, such as polyvinyl alcohol, is used as a dispersant or stabilizer in polymerization or micronization as necessary. May be used.
The heat-fusible fine particles are preferably dispersible in water, and the average particle size is preferably 0.01 to 10 μm, more preferably 0.1 to 3 μm. When the average particle size is smaller than 0.01 μm, when the coating liquid for the layer containing the heat-fusible fine particles is applied onto the porous hydrophilic layer described later, the heat-fusible fine particles It becomes easy to get into the pores or into the gaps between the fine irregularities on the surface of the hydrophilic layer, and the on-press development becomes insufficient, resulting in fear of soiling. When the average particle size of the heat-fusible fine particles is larger than 10 μm, the resolution is lowered.

  Further, the composition of the heat fusible particles may be continuously changed between the inside and the surface layer, or may be coated with a different material.

As a coating method, a known microcapsule formation method, a sol-gel method, or the like can be used.
As content of the thermoplastic fine particle in a layer, 1-90 mass% of the whole layer is preferable, and 5-80 mass% is more preferable.

  Examples of the microcapsules used in the printing plate material of the present invention include microcapsules enclosing a hydrophobic material described in JP-A No. 2002-2135 and JP-A No. 2002-19317.

The microcapsules preferably have an average diameter of 0.1 to 10 μm, more preferably 0.3 to 5 μm, and even more preferably 0.5 to 3 μm.
The thickness of the wall of the microcapsule is preferably 1/100 to 1/5 of the diameter, and more preferably 1/50 to 1/10.

The content of the microcapsule is 5 to 100% by mass of the entire image forming layer, preferably 20 to 95% by mass, and more preferably 40 to 90% by mass.
Known materials and methods can be used as the material for the wall of the microcapsule and the method for producing the microcapsule.

  For example, known materials and methods described in “New edition microcapsules, production method, properties, and application” (written by Tamotsu Kondo, Masumi Koishi / Sankyo Publishing Co., Ltd.) or cited references are used. be able to.

3.2 Binder The image forming layer may contain a water-soluble resin and a water-dispersible resin. Examples of water-soluble resins and water-dispersible resins include oligosaccharides, polysaccharides, polyethylene oxide, polypropylene oxide, polyvinyl alcohol, polyethylene glycol (PEG), polyvinyl ether, styrene-butadiene copolymers, and methyl methacrylate-butadiene copolymers. Examples thereof include resins such as conjugated diene polymer latex, acrylic polymer latex, vinyl polymer latex, polyacrylic acid, polyacrylate, polyacrylamide, and polyvinylpyrrolidone.

  Of these, oligosaccharides, polysaccharides, polyacrylic acid, polyacrylates (such as Na salts), and polyacrylamide are preferable.

  Examples of the oligosaccharide include raffinose, trehalose, maltose, galactose, sucrose, and lactose, and trehalose is particularly preferable.

  As polysaccharides, starches, celluloses, polyuronic acids, pullulans and the like can be used, but cellulose derivatives such as methyl cellulose salts, carboxymethyl cellulose salts, hydroxyethyl cellulose salts are particularly preferable, and sodium salts and ammonium salts of carboxymethyl cellulose are preferable. More preferred.

  The polyacrylic acid, polyacrylic acid, polyacrylate (Na salt, etc.), and polyacrylamide preferably have a molecular weight of 3,000 to 5,000,000, and more preferably 5,000 to 1,000,000.

3.3 Other materials that can be contained The image-forming layer can contain a photothermal conversion material described later. Since a part of the image forming layer is developed on-press, it is preferable to use a material that is less colored with visible light, and it is preferable to use a dye.

  The image forming layer can contain a water-soluble surfactant. A surfactant such as Si-based or F-based can be used, but it is particularly preferable to use a surfactant containing Si element because there is no fear of causing printing stains. The content of the surfactant is preferably 0.01 to 3% by mass, more preferably 0.03 to 1% by mass, based on the entire hydrophilic layer (solid content as the coating solution).

  Further, it may contain an acid (phosphoric acid, acetic acid, etc.) or an alkali (sodium hydroxide, silicate, phosphate, etc.) for pH adjustment.

4. Photothermal conversion materials 4.1 IR dyes Cyanine dyes, croconium dyes, polymethine dyes, azurenium dyes, squalium dyes, thiopyrylium dyes, naphthoquinone dyes, anthraquinone dyes, which are general infrared absorbing dyes Examples thereof include organic compounds, phthalocyanine-based, naphthalocyanine-based, azo-based, thioamide-based, dithiol-based, and indoaniline-based organometallic complexes. Specifically, JP-A-63-139191, JP-A-64-33547, JP-A-1-160683, JP-A-1-280750, JP-A-1-293342, JP-A-2-2074, Kaihei 3-26593, JP-A-3-30991, JP-A-3-34891, JP-A-3-36093, JP-A-3-36094, JP-A-3-36095, JP-A-3-42281, JP-A-3-42281 Examples thereof include compounds described in JP-A-3-97589, JP-A-3-103476, and the like. These can be used alone or in combination of two or more.
JP-A-11-240270, JP-A-11-265062, JP-A-2000-309174, JP-A-2002-49147, JP-A-2001-162965, JP-A-2002-144750, JP-A-2001-219667. The compounds described in 1 can also be preferably used.

4.2 Pigment Examples of the pigment include carbon, graphite, metal, and metal oxide.
As carbon, furnace black or acetylene black is particularly preferable. The particle size (d50) is preferably 100 nm or less, and more preferably 50 nm or less.

As the graphite, fine particles having a particle size of 0.5 μm or less, preferably 100 nm or less, more preferably 50 nm or less can be used.
As the metal, any metal can be used as long as the particle diameter is 0.5 μm or less, preferably 100 nm or less, more preferably 50 nm or less. The shape may be any shape such as a spherical shape, a piece shape, or a needle shape. Colloidal metal fine particles (Ag, Au, etc.) are particularly preferable.

As the metal oxide, a material that is black in the visible light region, or a material that has conductivity or is a semiconductor can be used.
Examples of the former include black iron oxide and black composite metal oxides containing two or more metals.

Examples of the latter include SnO ₂ doped with Sb (ATO), In ₂ O ₃ doped with Sn (ITO), TiO ₂ , TiO ₂ with reduced TiO ₂ (titanium oxynitride, generally titanium black), etc. Is mentioned. Further, it can also be used those obtained by coating the core material _{(BaSO 4, TiO 2, 9Al} 2 O 3 · 2B 2 O, K 2 O · nTiO 2 , etc.) in these metal oxides. These particle sizes are 0.5 μm or less, preferably 100 nm or less, and more preferably 50 nm or less.

Among these photothermal conversion materials, black iron oxide and black composite metal oxides containing two or more metals are more preferable materials.
The black iron oxide (Fe ₃ O ₄ ) is preferably particles having an average particle diameter of 0.01 to 1 μm and an acicular ratio (major axis diameter / minor axis diameter) of 1 to 1.5. It is preferably substantially spherical (acicular ratio 1) or has an octahedral shape (acicular ratio about 1.4).

  Examples of such black iron oxide particles include TAROX series manufactured by Titanium Industry Co., Ltd. As the spherical particles, BL-100 (particle diameter 0.2 to 0.6 μm), BL-500 (particle diameter 0.3 to 1.0 μm), or the like can be preferably used. Further, as octahedral shaped particles, ABL-203 (particle size 0.4 to 0.5 μm), ABL-204 (particle size 0.3 to 0.4 μm), ABL-205 (particle size 0.2 to 0) .3 μm), ABL-207 (particle size: 0.2 μm) and the like can be preferably used.

Furthermore, particles whose surface is coated with an inorganic substance such as SiO ₂ can also be preferably used. As such particles, spherical particles coated with SiO ₂ : BL-200 (particle size 0.2 to 0) .3 μm), octahedral shaped particles: ABL-207A (particle size 0.2 μm).

Specifically, the black composite metal oxide is a composite metal oxide composed of two or more metals selected from Al, Ti, Cr, Mn, Fe, Co, Ni, Cu, Zn, Sb, and Ba. . These are disclosed by methods disclosed in JP-A-8-27393, JP-A-9-25126, JP-A-9-237570, JP-A-9-241529, JP-A-10-231441, and the like. Can be manufactured.
The composite metal oxide used in the present invention is particularly preferably a Cu-Cr-Mn-based or Cu-Fe-Mn-based composite metal oxide. In the case of a Cu—Cr—Mn system, it is preferable to perform the treatment disclosed in JP-A-8-27393 in order to reduce the elution of hexavalent chromium. These composite metal oxides are colored with respect to the amount added, that is, they have good photothermal conversion efficiency.

  These composite metal oxides preferably have an average primary particle size of 1 μm or less, and more preferably have an average primary particle size in the range of 0.01 to 0.5 μm. When the average primary particle diameter is 1 μm or less, the photothermal conversion ability with respect to the addition amount becomes better, and when the average primary particle diameter is within the range of 0.01 to 0.5 μm, the photothermal conversion ability with respect to the addition amount is obtained. Better. However, the photothermal conversion ability with respect to the addition amount is greatly affected by the degree of dispersion of the particles, and the better the dispersion, the better.

  Therefore, it is preferable to disperse these composite metal oxide particles by a known method separately before adding them to the layer coating solution to prepare a dispersion (paste). An average primary particle size of less than 0.01 is not preferable because dispersion becomes difficult. A dispersing agent can be appropriately used for the dispersion. The addition amount of the dispersant is preferably 0.01 to 5% by mass, and more preferably 0.1 to 2% by mass with respect to the composite metal oxide particles.

5. Exposure (Image Formation) Method The image formation of the printing plate material according to one embodiment of the present invention can be performed by heat, but it is particularly preferable to perform image formation by exposure with an infrared laser.
More specifically, exposure relating to the present invention is preferably scanning exposure using a laser that emits light in the infrared and / or near-infrared region, that is, in the wavelength range of 700 to 1500 nm. A gas laser may be used as the laser, but it is particularly preferable to use a semiconductor laser that emits light in the near infrared region.

  As an apparatus suitable for scanning exposure according to the present invention, any apparatus can be used as long as it can form an image on the surface of a printing plate material in accordance with an image signal from a computer using the semiconductor laser. Good.

In general,
(1) A method of exposing the entire surface of the printing plate material by performing two-dimensional scanning using one or a plurality of laser beams on the printing plate material held by the plate-like holding mechanism,
(2) The circumferential direction of the cylinder (main scanning direction) using one or a plurality of laser beams from the inside of the cylinder to the printing plate material held along the cylindrical surface inside the fixed cylindrical holding mechanism ), Scanning the entire surface of the printing plate material by moving it in a direction perpendicular to the circumferential direction (sub-scanning direction),
(3) A printing plate material held on the surface of a cylindrical drum that rotates about an axis as a rotating body is rotated in the circumferential direction (main scanning direction) by rotating the drum using one or a plurality of laser beams from the outside of the cylinder. ) And moving in the direction perpendicular to the circumferential direction (sub-scanning direction) to expose the entire surface of the printing plate material.

  In the present invention, the scanning exposure method (3) is particularly preferable, and the exposure method (3) is used particularly in an apparatus that performs exposure on a printing apparatus.

6). On-machine development method The image forming layer of the printing plate material of the infrared laser heat melting and heat fusion method, which is a preferred embodiment of the printing plate material of the present invention, has an infrared laser exposed portion as an oleophilic image portion, and an unexposed portion. This layer is removed to form a non-image portion. The unexposed portion can be removed by washing with water, but it is also possible to perform so-called on-press development that removes with a dampening water and / or ink on a printing press.

  The removal of the unexposed portion of the image forming layer on the printing press can be performed by contacting a watering roller or an ink roller while rotating the plate cylinder. The various sequences can be performed. In that case, the water amount may be adjusted by increasing or decreasing the amount of dampening water required for printing, and the water amount adjustment may be divided into multiple stages or steplessly. You may change it to.

  (1) As a sequence for starting printing, a watering roller is contacted to rotate the plate cylinder from 1 to several tens of revolutions, then an ink roller is contacted to rotate the plate cylinder from one to several tens of rotations, Start printing.

  (2) As a sequence for starting printing, an ink roller is contacted to rotate the plate cylinder from 1 to several tens of rotations, then a watering roller is contacted to rotate the plate cylinder from 1 to 10 rotations, Start printing.

  (3) As a sequence for starting printing, the watering roller and the ink roller are brought into contact with each other substantially simultaneously to rotate the plate cylinder one to several tens of times, and then printing is started.

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated concretely, the embodiment of this invention is not limited to these.

<Production of support>
(Production of polyester film)
(Support 1: Polyethylene terephthalate support)
Using terephthalic acid and ethylene glycol, PET of IV (inherent viscosity) = 0.66 (measured in phenol / tetrachloroethane = 6/4 (mass ratio) at 25 ° C.) was obtained according to a conventional method. This is pelletized, dried at 130 ° C. for 4 hours, melted at 300 ° C., extruded from a T-die, rapidly cooled on a cooling drum at 50 ° C., and not yet thick enough to have an average film thickness of 175 μm after heat setting. A stretched film was prepared. With respect to the drawing temperature, the first drawing was stretched 1.3 times at 102 ° C. and the second drawing was longitudinally stretched 2.6 times at 110 ° C. Then, it was stretched 4.5 times at 120 ° C. with a tenter. Thereafter, the film was heat-fixed at 240 ° C. for 20 seconds and relaxed by 4% in the lateral direction at the same temperature. Thereafter, the chuck portion of the tenter was slit, knurled at both ends, cooled to 40 ° C. and wound at 4.8 kg / m. In this way, a biaxially stretched PET film having a thickness of 175 μm was obtained. The biaxially stretched PET film had a Tg of 79 ° C. The width of the obtained PET film (film forming width) was 2.5 m. Further, the thickness distribution of the obtained support 1 was 3%.

<< Preparation of underdrawn support 1 >>
Both sides of the film of the support 1 obtained above were subjected to a corona discharge treatment of 8 W / m ² · min, and then, as shown in Table 4, the following undercoat coating solution a was applied to one side as a dry film. After coating to a thickness of 0.8 μm, the undercoating liquid b was applied to a dry film thickness of 0.1 μm while performing corona discharge treatment (8 W / m ² · min), each at 180 ° C. for 4 minutes. Dried (undercoating surface A). Also, after coating the following undercoat coating solution c on the opposite side so as to have a dry film thickness of 0.8 μm, the undercoat coating solution d is dried film thickness 1 while performing corona discharge treatment (8 W / m ² · min). The coating was applied to a thickness of 0.0 μm and dried at 180 ° C. for 4 minutes (undercoating surface B). The surface electrical resistance at 25 ° C. and 25% RH after coating was 10 ⁸ Ω. Further, when the surface roughness of the surface on the undercoat surface B side was measured, the Ra value was 0.8 μm. Subsequently, the surface of each undercoat layer was subjected to plasma treatment under the following plasma treatment conditions.

<< Undercoat coating liquid a >>
Styrene / glycidyl methacrylate / butyl acrylate = 60/39/1 ternary copolymer latex (Tg = 75 ° C.) 6.3% (based on solid content)
Styrene / glycidyl methacrylate / butyl acrylate = 20/40/40 terpolymer latex 1.6%
Anionic surfactant S-1 0.1%
Water 92.0%
<< Undercoat coating liquid b >>
Gelatin 1%
Anionic surfactant S-1 0.05%
Hardener H-1 0.02%
Matting agent (silica, average particle size 3.5 μm) 0.02%
Antifungal agent F-1 0.01%
Water 98.9%

<< Undercoat coating liquid c >>
Styrene / glycidyl methacrylate / butyl acrylate = 20/40/40 ternary copolymer latex 0.4% (based on solid content)
Styrene / glycidyl methacrylate / butyl acrylate / acetoacetoxyethyl methacrylate = 39/40/20/1 quaternary copolymer latex 7.6%
Anionic surfactant S-1 0.1%
Water 91.9%
<< Undercoat coating liquid d >>
Conductive composition of component d-1 / component d-2 / component d-3 = 66/31/1 6.4%
Hardener H-2 0.7%
Anionic surfactant S-1 0.07%
Matting agent (silica, average particle size 3.5 μm) 0.03%
Water 93.4%
Component d-1;
An anionic polymer compound comprising a copolymer of sodium styrenesulfonate / maleic acid = 50/50; component d-2;
Three-component copolymer latex consisting of styrene / glycidyl methacrylate / butyl acrylate = 40/40/20 component d-3;
Polymeric activator comprising styrene / sodium isoprenesulfonate = 80/20

  As is apparent from the table, the sample of the present invention is superior to the comparison.

Claims (5)

An image having a chemically active shell, core / shell structure fine particles having a core having a chemically active shell and a softening point lower by 40 ° C. than the chemically active shell, and a hydrophilic polymer on a hydrophilic support. Forming material. 2. The image forming material according to claim 1, wherein the softening point of the shell is 20 degrees or more and the core is 60 degrees or more. The image forming material according to claim 1 or 2 is heated in an image shape, the shell is softened to fuse the shells together and chemically bonded, and the image forming material is treated with an aqueous medium and heated. An image forming method, wherein an image is obtained through a step of removing a portion of the image forming layer that has not been formed. 3. An image forming method, wherein the image forming material according to claim 1 is scanned with a laser beam to be heated in an image form to obtain an image. An image forming material according to claim 1 or 2, wherein the image forming material is produced.