JP2012139643A - Microcapsule and manufacturing method therefor, and planographic printing original plate using the microcapsule and platemaking method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a microcapsule including a photo-polymerizable compound, of which microencapsulation reaction is rapid, as a core substance, and its manufacturing method; and to provide a planographic printing original plate for CTP containing the microcapsule and having high printing durability while maintaining stain resistance and storage stability, and a plate making method including on-pess developing.SOLUTION: The core substance of the microcapsule is a polymerizable-unsaturated-group containing compound and a trivalent phosphorous compound, and the shell component including the core substance has a molecular structure having urea binding. The planographic printing original plate includes an image recording layer on a hydrophilic support, wherein the image recording layer includes a polymerizable composition containing a radical polymerizable compound (A), a sensitizing dye (B), a polymerization initiator (C), and the microcapsule (D).

Description

  INDUSTRIAL APPLICABILITY The present invention provides a microcapsule that can be used for photosensitive and heat-sensitive recording materials, a method for producing the same, and a so-called direct plate making that can be directly made using a digital signal from a computer or the like using various lasers. The present invention relates to a lithographic printing plate precursor, particularly a lithographic printing plate precursor having improved printing durability, stain resistance and storage stability, and a plate making method thereof.

  Solid lasers, semiconductor lasers, and gas lasers that emit ultraviolet light, visible light, and infrared light having a wavelength of 300 nm to 1200 nm are easily available in high output and small size. It is very useful as a recording light source when making a plate directly from digital data. Various studies have been conducted on recording materials that are sensitive to these various laser beams. In particular, when a material that can be recorded with an infrared laser having a photosensitive wavelength of 760 nm or more is used, there is an advantage that handling in a bright room becomes easy. As a representative example, for example, radical polymerization described in Patent Document 1 Type negative recording material.

In addition, in a conventional lithographic printing plate precursor (hereinafter also referred to as PS plate), after exposure, a step (development processing) for dissolving and removing the non-image part is indispensable, and the developed printing plate is washed with water, A post-treatment step is also necessary, in which treatment is performed with a rinse solution containing a surfactant or treatment with a desensitizing solution containing gum arabic or a starch derivative. 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, processing with a developing solution closer to the neutral range and a small amount of waste liquid are cited as problems. Furthermore, it is desirable to simplify the wet post-treatment or change to a dry treatment.

  From this point of view, one method of eliminating the processing step is to mount the exposed printing original plate on the cylinder of the printing press, and supply dampening water and ink while rotating the cylinder to remove the non-printing original plate. There is a method called on-machine development that removes the image area. That is, after the printing original is exposed, it is mounted on a printing machine as it is, and the developing process is completed in a normal printing process.

In order to satisfy the requirements for on-press development, a lithographic printing plate precursor in which an image recording layer in which thermoplastic hydrophobic polymer fine particles are dispersed in a hydrophilic binder polymer is provided on a hydrophilic support has been proposed ( For example, see Patent Document 2). In making the plate, it is exposed with an infrared laser, and the thermoplastic hydrophobic polymer fine particles are coalesced (fused) with heat generated by photothermal conversion to form an image. On-press development can be performed by supplying at least one of water and ink. This lithographic printing plate precursor also has handleability in a bright room because the photosensitive region is an infrared region.
However, an image formed by coalescence (fusion) of thermoplastic hydrophobic polymer fine particles has insufficient strength and has a problem in printing durability as a printing plate.

Further, a lithographic printing plate precursor including microcapsules encapsulating a polymerizable compound in place of the thermoplastic fine particles has been proposed (see, for example, Patent Documents 3 to 8). The original plate according to such a proposal has an advantage that the polymer image formed by the reaction of the polymerizable compound is superior in strength to the image formed by fusing fine particles.
In addition, since the polymerizable compound has high reactivity, many methods for isolating it using microcapsules have been proposed. It has been proposed to use a thermally decomposable polymer for the shell of the microcapsule.

  In the microcapsules described in Patent Documents 3 to 8, the reaction rate during synthesis is slow, and isocyanato groups tend to remain. For this reason, when it is introduced into the image recording layer of the lithographic printing plate precursor, the storage stability is deteriorated. On the other hand, if the reaction time is set long, the microcapsules tend to aggregate during the production.

  In addition, the conventional lithographic printing plate precursors described in Patent Documents 1 to 8 are not sufficient in printing durability of images formed by laser exposure, and further improvements are required. That is, it is difficult to obtain sufficient printing durability in an image cured with a material that can be recorded with an infrared laser having a photosensitive wavelength of 760 nm or more. If a support having a surface with low hydrophilicity is used in order to improve printing durability, ink will also adhere to non-image areas during printing, resulting in printing stains. As described above, in the case of a material that can be recorded with an infrared laser having a photosensitive wavelength of 760 nm or more, there is a problem that the stain resistance is good and sufficient printing durability is provided. In particular, in the on-press development using fountain solution and / or printing ink, the developability is inferior to that of a system developing with an alkaline developer, and therefore, it is easily contaminated and becomes a more difficult problem.

JP 2004-212558 A Japanese Patent No. 2938397 JP 2000-2111262 A JP 2001-277740 A JP 2002-29162 A JP 2002-46361 A JP 2002-137562 A JP 2002-326470 A

  An object of the present invention is to provide a microcapsule having a photopolymerizable compound as a core substance, which has a fast microencapsulation reaction, and a method for producing the same. Another object of the present invention is to provide a lithographic printing plate precursor for CTP, which contains this microcapsule, maintains stain resistance and storage stability and has high printing durability, and a plate making method including on-press development. .

1. A microcapsule wherein the core material is a polymerizable unsaturated group-containing compound and a trivalent phosphorus compound, and the shell wall component containing the core material has a urea bond in the molecular structure.
2. The core material is a polymerizable unsaturated group-containing compound and a trivalent phosphorus compound, and the shell wall component containing this core material has a urea bond obtained by reaction with a polyisocyanate compound and water in the molecular structure. 2. The microcapsule according to 1 above, characterized by.
3. In the above 1 or 2, wherein the polyisocyanate compound is an adduct of a compound having two or more hydroxy groups in the molecule and a polyfunctional isocyanate compound having two or more isocyanate groups in the molecule. The microcapsule described.
4). 4. The microcapsule according to 3 above, wherein the compound having two or more hydroxy groups in the molecule is a polyhydric phenol.
5. A method for producing a microcapsule, comprising emulsifying and dispersing an organic phase containing a trivalent phosphorus compound, a polymerizable unsaturated group-containing compound, and a polyisocyanate compound in an aqueous phase.
6). 6. The polyisocyanate compound is an adduct of a compound having two or more hydroxy groups in the molecule and a polyfunctional isocyanate compound having two or more isocyanate groups in the molecule. Manufacturing method of microcapsule.
7). 7. The method for producing a microcapsule according to 6 above, wherein the compound having two or more hydroxy groups in the molecule is a polyhydric phenol.
8). On the hydrophilic support, (A) a radically polymerizable compound, (B) a sensitizing dye, (C) a polymerization initiator, and (D) the microcapsule according to any one of the above 1 to 4 is contained. A lithographic printing plate precursor comprising an image recording layer containing a polymerizable composition.
9. The lithographic printing plate precursor as described in 8 above, wherein the (B) sensitizing dye is an infrared absorber.
10. The lithographic printing plate precursor as described in 8 or 9 above, which comprises an image recording layer containing the polymerizable composition and a layer containing an inorganic stratiform compound in this order.
11. The lithographic printing plate precursor as described in any one of 8 to 10 above, wherein the unexposed portion of the image recording layer can be removed with at least one of dampening water and printing ink.
12 A lithographic printing plate precursor as described in 11 above, image-exposed with an infrared laser, and then the unexposed portion of the image recording layer is removed with at least one of dampening water and printing ink.

  Although the mechanism of action of the present invention is not clear, since the trivalent phosphorus compound promotes the formation of bonds between the isocyanato groups and between the isocyanato group and the urethane bond or urea bond, the microencapsulation reaction rate is improved. Inferred. Further, the obtained microcapsules have a high crosslinking density, and it is presumed that when added to the image recording layer of the planographic printing plate, the strength of the image area is improved and the printing durability is improved.

  In the microcapsule of the present invention, the core substance may be extracted by mixing with an organic solvent, and the microcapsule is defined as the core substance extracted from the microcapsule. In the image recording layer, the core substance may be extracted by an organic solvent and exist as a microgel.

  According to the present invention, it is possible to provide a microcapsule that can be used for photosensitive and heat-sensitive recording materials and a method for producing the same. In addition, a lithographic printing plate precursor containing microcapsules having high productivity capable of so-called direct plate making that can be directly made using various lasers from a digital signal from a computer or the like can be obtained. In particular, an on-press development type lithographic printing plate precursor having good printing durability, storage stability and stain resistance can be obtained.

[Microcapsule]
In the microcapsule of the present invention, the core material is a polymerizable unsaturated group-containing compound and a trivalent phosphorus compound, and the shell wall component containing the core material has a urea bond in the molecular structure. Hereinafter, components constituting the microcapsule will be sequentially described.

[Trivalent phosphorus compound]
The trivalent phosphorus compound used for the microcapsules of the present invention is represented by the following general formula (I).

In the general formula ^{(I), R 1, R} 2, R 3 is a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, an aryl group, an aralkyl group, -OR ^4, or an -SR ^4, R ⁴ is , A hydrogen atom, an alkyl group having 1 to 20 carbon atoms, an aryl group, or an aralkyl group.
These groups may have a substituent, and examples of the substituent include a halogen atom, an alkoxy group having 1 to 20 carbon atoms, an alkoxycarbonyl group, an acyloxy group, an acyl group, a cyano group, and a hydroxy group. It is done.

  Examples of the trivalent phosphorus compound include triarylphosphine, trialkylphosphine, phosphite ester, thiophosphite ester and derivatives thereof, but the microencapsulation reaction rate is high and the stability of the compound is also good. Of these, phosphites, thiophosphites, and triarylphosphine derivatives are preferable, and triarylphosphine derivatives are particularly desirable.

  Specific examples of the trivalent phosphorus compound of the present invention include the following compounds.

  Triphenylphosphine, (S)-(−)-BINAP, (R)-(+)-BINAP, (+/−)-BINAP, 2,2′-bis (diphenylphosphino) biphenyl, 1,4-bis (Diphenylphosphino) butane, 4,5-bis (diphenylphosphino) -9,9-dimethylxanthene, 1,2-bis (diphenylphosphino) ethane, 1,1′-bis (diphenylphosphino) ferrocene, 1,6-bis (diphenylphosphino) hexane, bis (diphenylphosphino) methane, 4,6-bis (diphenylphosphino) phenoxazine, bis [2- (diphenylphosphino) phenyl] ether, cyclohexyldiphenylphosphine, Di-tert-butylphenylphosphine, 2- (di-tert-butylphosphino) bif Nyl, dicyclohexylphenylphosphine, 2- (dicyclohexylphosphino) biphenyl, diethylphenylphosphine, 4- (dimethylamino) phenyldiphenylphosphine, 2- (diphenylphosphino) benzoic acid, 4- (diphenylphosphino) benzoic acid, diphenyl 2-pyridylphosphine, ethyldiphenylphosphine, isopropyldiphenylphosphine, methyldiphenylphosphine, (pentafluorophenyl) diphenylphosphine, (R, R ″)-2,2 ″ -bis (diphenylphosphino) -1,1 '' -Biferrocene, sodium diphenylphosphinobenzene-3-sulfonate, tricyclohexylphosphine, tri (2-furyl) phosphine, trihexylphosphine, tri-n-octylphosphine , Triphenylphosphine, tris (2,6-dimethoxyphenyl) phosphine, tris (4-methoxyphenyl) phosphine, tris (4-methylphenyl) phosphine, tris (2-methylphenyl) phosphine, tris (3-methyl Phenyl) phosphine, tris (pentafluorophenyl) phosphine, tri (2-thienyl) phosphine, trilauryl trithiophosphite, trihexyl phosphite, triisodecyl phosphite, trimethylolpropane phosphite

  The addition amount of these trivalent phosphorus compounds is preferably 0.01 to 20% by mass, more preferably 0.5 to 10% by mass, based on the total solid content of the microcapsules. Within this range, a lithographic printing plate precursor having good storage stability can be obtained.

(Polymerizable unsaturated group-containing compound)
Examples of the polymerizable unsaturated group-containing compound include a compound having an ethylenically unsaturated group and a compound having an epoxy group, and a compound having an ethylenically unsaturated group having a relatively high photopolymerization rate is particularly desirable.

  The compound containing an ethylenically unsaturated group used for the core material of the microcapsule is particularly preferably defined by the following formula (b).

L ¹ Lc _m Z _n (b)
In Formula (b), L ¹ is an m + n-valent linking group, m and n are each independently an integer of 1 to 100, Lc is a monovalent ethylenically unsaturated group, and Z is a nucleophilic group.

L ¹ represents a divalent or higher aliphatic group, a divalent or higher aromatic group, a divalent or higher heterocyclic group, —O—, —S—, —NH—, —N <, —CO—, —SO. -, - SO ₂ - or preferably a combination thereof.
m and n are each independently an integer of 1 to 50, preferably an integer of 2 to 20, more preferably an integer of 3 to 10, and an integer of 3 to 5. Most preferably it is.
Examples of the monovalent ethylenically unsaturated group represented by Lc include an allyl group, a vinyl group, an acryloyl group, and a methacryloyl group.
The nucleophilic group represented by Z, OH, preferably SH or NH _2, more preferably OH or NH _2, OH is most preferred.

  Although the example of the polymeric compound containing an ethylenically unsaturated group is shown below, it is not limited to this structure.

  These polymerizable compounds may be used alone or in combination of two or more.

[Method for producing microcapsules]
Hereinafter, the microcapsule manufacturing method of the present invention will be described sequentially.

[Production method of microcapsules]
The microcapsule having a polyurea wall of the present invention is synthesized by an interfacial polymerization reaction. That is, the trivalent phosphorus compound of the present invention, a polyisocyanate compound, and a polymerizable group-containing unsaturated compound are added to an organic solvent, and this organic phase solution is emulsified in a water-soluble polymer aqueous solution. Thereafter, if necessary, a catalyst for promoting the polymerization reaction is added to the aqueous phase, or the temperature of the emulsion is raised to polymerize the polyisocyanate compound with a compound having active hydrogen such as water to form microcapsules.

[Polyisocyanate compound]
As the microcapsule wall material of the present invention, a polyisocyanate compound is preferably used. A preferred polyisocyanate compound is an adduct of a compound having two or more hydroxy groups in the molecule and a polyfunctional isocyanate compound having two or more isocyanate groups in the molecule. The compound having two or more hydroxy groups in the molecule is preferably a polyhydric phenol rather than a polyhydric alcohol.

[Polyhydric alcohol]
Specific examples of the polyhydric alcohol include polyhydric alcohols having two hydroxy groups such as ethylene glycol, propylene glycol, butylene glycol, diethylene glycol, and triethylene glycol, and hydroxy groups such as glycerin, trimethylolpropane, and triethanolamine. Polyhydric alcohol having three hydroxy groups such as polyhydric alcohol having three, pentaerythritol, diglycerin, xylose, sorbitan, etc., polyhydric alcohol having five hydroxy groups such as xylitol, triglycerin, glucose, fructose, sorbitol, 2 such as polyhydric alcohol having 6 hydroxy groups such as malbitol, tetraglycerin, polyglycerin having more than 6 hydroxy groups, sucrose, trehalose, lactose S, such as 3 saccharides such as maltotriose. These may be used alone or in combination of two or more. Among these, 2-5 polyhydric alcohols having a hydroxy group are more preferable, and 3-4 polyhydric alcohols having a hydroxy group are particularly preferable. With 6 or more polyhydric alcohols, the hydrophilicity is too high and it is difficult to dissolve in an organic solvent, and the resulting polyisocyanate has a high viscosity and is difficult to handle.

[Polyphenol]
The polyhydric phenol is a compound having a plurality of phenolic hydroxy groups in one molecule, and preferably a compound having a plurality of benzene rings having a phenolic hydroxy group in one molecule.
More preferably, it is a polyhydric phenol compound having 3 or more phenolic hydroxy groups in the molecule. Particularly preferred compounds are polyhydric phenol compounds having three or more hydroxy groups in the molecule represented by the general formula (1) or (2).

In the general formula (1), R ¹ and R ² each independently represent a hydrogen atom, a methyl group, a methoxymethyl group or a cycloalkyl group having 3 to 6 carbon atoms, and R ³ represents a hydrogen atom, a methyl group or The group represented by the following formula (a) is represented. R ¹ and R ² in the formula (a) is the general formula (1) have the same meanings as R ¹ and R ^2, n represents an integer of 0 to 2. R ⁹ represents a hydrogen atom, a methyl group or a cyclohexyl group.

In the general formula (1), R ⁴ represents a methyl group or a group represented by the formula (a), and R ⁵ represents a group selected from the following group A. In the following group A, R ¹ and R ² have the same meanings as R ¹ and R ² in general formula (1).

In the general formula (2), R ⁶ represents a hydrogen atom, a methyl group, a phenyl group or a cyclohexyl group, and R ⁷ and R ⁸ are each independently a hydrogen atom, a methyl group, a methoxymethyl group or a carbon number of 3 to 3. 6 represents a cycloalkyl group, and m represents 0 or 1.

  Specific examples of the polyphenol compound represented by the above general formula (1) or (2) of the present invention include the following compounds.

  Among these, compounds of P-1, P-2, P-5, P-8, P-10 and P-14 are particularly preferable.

  In the present invention, among the polyphenol compounds represented by the general formula (1) or (2), a compound having a value of (inorganic) / (organic) of 0.3 to 1.0. It is preferable to use it. The numbers (I / O) shown in parentheses in the above specific examples indicate the values of (inorganic) / (organic), “Organic Conceptual Diagram—Basics and Applications” (by Yoshio Koda, Sankyo Publishing Co., Ltd.) 1984). The increase in (organic) in the above (inorganic) / (organic) depends mainly on the number of carbon atoms of the organic compound, and is calculated with 20 for one carbon atom. The increase in (inorganic property) mainly depends on the substituent of the organic compound, and one hydroxy group is set to 100, and is determined based on the influence on the boiling point of the group. The value of (inorganic) / (organic) in the above range is 1.0 for phenol, and the polyhydric phenol compound in the above range has the same or higher ratio of hydrocarbons than phenol. I can say that. Since microcapsules obtained using an isocyanate adduct (polyfunctional isocyanate) obtained from this compound have hydrophobicity, it is presumed that the printing durability is improved by suppressing the water permeability of the image area.

[Polyfunctional isocyanate compound]
As the polyfunctional isocyanate compound having two or more isocyanate groups in the molecule that reacts with the polyhydric phenol compound to form an adduct, a known compound can be used, and two isocyanates in the molecule. A bifunctional isocyanate having a group is particularly preferred. Examples thereof include aromatic isocyanate compounds and aliphatic isocyanate compounds. Specifically, the following can be mentioned.

Isophorone diisocyanate, m-phenylene diisocyanate, p-phenylene diisocyanate, 2,6-tolylene diisocyanate, 2,4-tolylene diisocyanate, naphthalene-1,4-diisocyanate, diphenylmethane-4,4′-diisocyanate, 3,3 ′ -Dimethoxy-biphenyl diisocyanate, 3,3'-dimethyldiphenylmethane-4,4'-diisocyanate, xylylene-1,4-diisocyanate, xylylene-1,3-diisocyanate, 4-chloroxylylene-1,3-diisocyanate, 2 -Methylxylylene-1,3-diisocyanate, 4,4'-diphenylpropane diisocyanate, 4,4'-diphenylhexafluoropropane diisocyanate, trimethylene diisocyanate, hexame Range isocyanate, propylene-1,2-diisocyanate, butylene-1,2-diisocyanate, cyclohexylene-1,2-diisocyanate, cyclohexylene-1,3-diisocyanate, cyclohexylene-1,4-diisocyanate, dicyclohexylmethane-4 , 4'-diisocyanate, 1,4-bis (isocyanatemethyl) cyclohexane and 1,3-bis (isocyanatemethyl) cyclohexane.
Among these, isophorone diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, xylylene-1,4-diisocyanate and xylylene-1,3-diisocyanate are preferable.
Further, these compounds as main raw materials, these trimers (burette or isocyanurate), polyfunctional adducts (adducts) with polyols such as trimethylol propane, formalin condensate of benzene isocyanate Etc. are also preferable.
Among these, isophorone diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, xylylene-1,4-diisocyanate and xylylene-1,3-diisocyanate are particularly preferable.

  In the combination of the polyhydric phenol compound and the polyfunctional isocyanate compound, a combination of a polyhydric phenol compound having three or more hydroxy groups in the molecule and a bifunctional isocyanate compound is preferable, and in the general formula (1) or (2), The combination of the polyhydric phenol compound and bifunctional isocyanate represented is more preferable, the combination of the polyhydric phenol compound represented by the general formula (1) or (2) and isophorone diisocyanate is particularly preferable, and most preferably P -2 is a combination of a polyhydric phenol compound represented by -2 and isophorone diisocyanate.

[Synthesis Method of Polyisocyanate Compound]
An adduct of a polyhydric phenol compound having three or more hydroxy groups in the molecule represented by the general formula (1) or (2) and a polyfunctional isocyanate compound having two or more isocyanate groups in the molecule is: For example, a polyhydric phenol compound and a bifunctional isocyanate compound are heated in an organic solvent with stirring (50 to 100 ° C.), or a catalyst such as stannous octylate is added at a relatively low temperature (40 It can be obtained by heating at ~ 70 ° C. In general, the number of moles (number of molecules) of the polyfunctional isocyanate compound to be reacted with the polyhydric phenol compound is 0.8 to 1.5 times the number of moles of hydroxy groups (number of equivalents of hydroxy groups) in the polyhydric phenol compound. The polyfunctional isocyanate compound having the number of moles (number of molecules) is used.

  The isocyanate compound obtained by the above reaction can be methylurethanated with methanol to measure the molecular weight (polystyrene conversion value), and the number average molecular weight is preferably from 500 to 15000, particularly preferably from 1000 to 10,000.

  Examples of the organic solvent include ethyl acetate, chloroform, tetrahydrofuran, methyl ethyl ketone, acetone, acetonitrile, toluene and the like.

[Combination of polyisocyanate compound]
As an isocyanate compound that is a raw material for microcapsules, in combination with an adduct of the polyhydric phenol compound of the present invention and a polyfunctional isocyanate, another polyfunctional isocyanate compound having two or more isocyanate groups in the molecule is used in combination. Can do. Examples of other polyfunctional isocyanate compounds having two or more isocyanate groups in the molecule include xylene diisocyanate and hydrogenated products thereof, hexamethylene diisocyanate, tolylene diisocyanate and hydrogenated products thereof, and diisocyanates such as isophorone diisocyanate. For example, known compounds can be mentioned. Further, these compounds as main raw materials, these trimers (burette or isocyanurate), polyfunctional adducts (adducts) with polyols such as trimethylol propane, formalin condensate of benzene isocyanate Etc. can also be used. Among these, xylene diisocyanate, tolylene diisocyanate, and isophorone diisocyanate are particularly preferable. These compounds are described in “Polyurethane Resin Handbook” (edited by Keiji Iwata, published by Nikkan Kogyo Shimbun (1987)).

[Active hydrogen compound]
In the present invention, water is generally used as the compound having active hydrogen that reacts with the polyvalent isocyanate compound for forming the microcapsule wall during microencapsulation. Polyols can also be used as compounds having active hydrogen. The polyol is used by being added to an oil phase as a core or an aqueous phase containing a water-soluble polymer as a dispersion medium. Specific examples include propylene glycol, glycerin, and trimethylolpropane.

[Microcapsule having hydrophilic polymer in side chain]
The aspect of the microcapsule having a hydrophilic polymer functioning as a protective colloid as a side chain on its surface is particularly preferable from the viewpoint of developability.

[Method of introducing hydrophilic polymer into microcapsules]
A polyfunctional isocyanate compound having two or more isocyanate groups is dissolved in a water-immiscible solvent, and this solution contains a hydrophilic polymer having one or more active hydrogen groups capable of reacting with isocyanate groups at one end. After emulsifying and dispersing in an aqueous solution, it may be produced by removing the solvent from the oil droplets of the emulsified dispersion, or reacting a polyfunctional isocyanate compound and a hydrophilic polymer having one or more active hydrogen groups at one end. Then, it may be prepared by dissolving in a solvent immiscible with water, emulsifying and dispersing the solution in an aqueous solution, and then removing the solvent from the oil droplets of the emulsified dispersion.

[Hydrophilic polymer having one or more active hydrogen groups at one end]
A hydrophilic polymer having at least one active hydrogen group capable of reacting with an isocyanate group at one end will be described. Examples of the active hydrogen group that can react with the isocyanate group include a hydroxy group, an amino group, a mercapto group, and a carboxy group. Of these, a hydroxy group and an amino group are particularly preferable. The hydrophilic polymer having such an active hydrogen group is not particularly limited, and examples thereof include a compound having a polyoxyalkylene chain having an active hydrogen group at one end.
The mass average molar mass (Mw) of the hydrophilic polymer is preferably 300 to 500,000, and more preferably 500 to 100,000. When Mw is from 300 to 500,000, it has a sufficient function as a protective colloid, can ensure the dispersion stability of the microcapsules, and can sufficiently obtain the hydrophilicity of the surface.

As specific examples of the hydrophilic polymer, examples of the compound having a polyoxyalkylene chain include polyethylene oxide and ethylene oxide / propylene oxide copolymer. These polymers are, for example, ring-opening polymerization of a cyclic compound such as ethylene oxide and propylene oxide using alcohol, alkoxide, carboxylic acid, carboxylate, etc. as a polymerization initiation terminal, and the polymerization initiation terminal at a conventionally known reaction (for example, hydrolysis reaction). , Reduction reaction, etc.) can be synthesized by converting into an active hydrogen group such as a hydroxy group or an amino group. A polyether having an active hydrogen group at one end can also be used. Among these, polyethylene oxide monoethers (the monoethers include monomethyl ether, monoethyl ether, etc.), polyethylene oxide monoesters (the monoesters include monoacetic acid esters, mono (meth) acrylic acid esters) Etc.) are more preferable.
Among these, polyether derivatives having a terminal amino group or a terminal hydroxy group represented by the following general formula (c) are preferable.

In general formula (c), Y represents an amino group or a hydroxy group. X represents a linking group. A preferred linking group includes —C (═O) — or SO ₂ —. Among them, -C (= O)-is preferable.
In general formula (c), m represents 0 or 1. A represents an arylene group or an alkylene group.

  The arylene group represented by A may have a substituent, and an arylene group having a total carbon number of 6 to 30 is preferable, and an arylene group having a total carbon number of 6 to 20 is particularly preferable. When substituted, the substituent is preferably a halogen atom, an alkyl group, an alkoxy group, an alkoxycarbonyl group, an aryloxycarbonyl group, or a cyano group, and particularly preferably an alkyl group or an alkoxy group. Specific examples of such an arylene group include a phenylene group, a biphenylene group, a naphthylene group, a tolylene group, and a (methoxy) phenylene group.

  The alkylene group represented by A is preferably an alkylene group having 1 to 30 carbon atoms, and particularly preferably an alkylene group having 1 to 20 carbon atoms. Specific examples of such an alkylene group include a methylene group, an ethylene group, a propylene group, and a tetramethylene group.

In the general formula (c), specific examples of such a group represented by-(X) _m -AY include an aminoethyl group, an aminopropyl group, a 4-aminobenzoyl group, and a 3-aminobenzoyl group. 4-aminobenzenesulfonyl group, aminoacetyl group, aminoethylsulfonyl group, hydroxyethyl group, hydroxypropyl group, 4-hydroxybenzoyl group, 3-hydroxybenzoyl group, 4-hydroxybenzenesulfonyl group, hydroxyacetyl group, hydroxyethyl A sulfonyl group, and the like.

  In general formula (c), L represents an alkylene group. The alkylene group represented by L may have a substituent or may have a branch, and is preferably an alkylene group having 2 to 20 carbon atoms, particularly 2 to 2 carbon atoms. Ten alkylene groups are preferred. When substituted, the substituent is preferably an aryl group, an alkenyl group, an alkoxy group, or an acyl group, and particularly preferably an aryl group. Specific examples of such an alkylene group include an ethylene group, a propylene group, a tetramethylene group, a phenylethylene group, a cyclohexylene group, a vinylethylene group, and a phenoxymethylethylene group, and an ethylene group and a propylene group are particularly preferable. Most preferably, it is an ethylene group.

In the general formula (c), the repeating unit-(L-O) _n -may be independently L in n repeating units, but it is particularly preferable that Ls are the same. Specific examples of the polyether having such a repeating unit include polyethylene oxide, polypropylene oxide, polytetramethylene oxide, polystyrene oxide, polycyclohexylene oxide, polyethylene oxide-polypropylene oxide-block copolymer, polyethylene oxide-polypropylene oxide. A random copolymer etc. are mentioned. Of these, polyethylene oxide, polypropylene oxide, and polyethylene oxide-polypropylene oxide block copolymers are preferable, and polyethylene oxide is most preferable.

  In the general formula (c), R represents an organic group having no active hydrogen. R is not particularly limited as long as it is an organic group having no active hydrogen that reacts with an isocyanate group, and preferred organic groups include alkyl groups, aryl groups, and acyl groups. More preferred is an alkyl group.

  As the alkyl group represented by R, those having 1 to 30 total carbon atoms are preferable, and those having 1 to 20 total carbon atoms are particularly preferable. Specific examples of such an alkyl group include a methyl group, an ethyl group, a butyl group, an isopropyl group, a benzyl group, and a methoxyethyl group. A methyl group is most preferred.

  As the aryl group represented by R, those having a total carbon number of 6 to 30 are preferable, and those having a total carbon number of 6 to 20 are particularly preferable. Specific examples of such an aryl group include a phenyl group, a nonylphenyl group, an octylphenyl group, and a methoxyphenyl group.

  The acyl group represented by R may be an aliphatic acyl group or an aromatic acyl group, may have a substituent, may have a branch, and has a total carbon number of 2 To 30 are preferable, and those having 2 to 20 carbon atoms are particularly preferable. Specific examples of such an acyl group include an acetyl group, a benzoyl group, a (meth) acryloyl group, an oleoyl group, a lauroyl group, a stearoyl group, and a methoxybenzoyl group.

  As described above, among these groups represented by R, an alkyl group is preferable.

  In the general formula (c), n represents an average addition mole number of the polyether group and represents a number of 10 to 120, and the average addition mole number is preferably 12 to 100.

  Specific examples of the polyether derivative having a terminal amino group or a terminal hydroxy group represented by the general formula (c) are shown below, but the present invention is not limited thereto.

[Water-soluble polymer for dispersing oil phase in water phase]
Water-soluble polymers for dispersing the oil phase of the microcapsules in the aqueous phase include polyvinyl alcohol and its modified products, polyacrylic amide and its derivatives, ethylene / vinyl acetate copolymer, styrene / maleic anhydride copolymer. Polymer, ethylene / maleic anhydride copolymer, isobutylene / maleic anhydride copolymer, polyvinylpyrrolidone, ethylene / acrylic acid copolymer, vinyl acetate / acrylic acid copolymer, carboxymethylcellulose, methylcellulose, casein, gelatin, Mention may be made of starch derivatives, arabic gum and sodium alginate. These water-soluble polymers are preferably those that do not react with isocyanate compounds or that are extremely difficult to react. For example, those having a reactive amino group in the molecular chain such as gelatin may be pre-removed. is necessary.

[Surfactant]
In microencapsulation, a surfactant may be added to either the oil phase or the aqueous phase, but it is easier to add to the aqueous phase because of its low solubility in organic solvents. The addition amount is preferably 0.1 to 5% by mass, particularly 0.5 to 2% by mass, based on the mass of the oil phase. In general, surfactants used for emulsification and dispersion are considered to be superior surfactants having a relatively long-chain hydrophobic group. “Surfactant Handbook” (Nishi Ichiro et al., Sangyo Tosho (1980)), alkyl Alkali metal salts such as sulfonic acid and alkylbenzene sulfonic acid can be used.

  In the present invention, compounds such as aromatic sulfonate formalin condensates and aromatic carboxylate formalin condensates can also be used as surfactants (emulsification aids). Specific examples include compounds represented by the following general formula. This compound is described in JP-A-06-297856.

In the above formula, R represents an alkyl group having 1 to 4 carbon atoms, X represents SO ₃ ⁻ or COO ⁻ , M represents Na ⁺ or K ⁺ , and q represents an integer of 1 to 20.

  Alkyl glucoside compounds can also be used in the same manner. Specific examples include compounds represented by the following general formula.

  In the above formula, R represents an alkyl group having 4 to 18 carbon atoms, and q represents an integer of 0 to 2.

  In the present invention, any surfactant may be used alone or in combination of two or more.

[Particle size of microcapsules]
The average particle size of the microcapsules is preferably 0.01 to 3.0 μm. 0.05-2.0 micrometers is still more preferable, and 0.10-1.0 micrometer is especially preferable. Within this range, good resolution and stability over time can be obtained.

[Lithographic printing plate precursor]

The lithographic printing plate precursor according to the invention has an image recording layer on a hydrophilic support. If necessary, an undercoat layer can be provided between the support and the image recording layer, and a protective layer can be provided on the image recording layer. The protective layer may have a multilayer structure. You may have a backcoat layer in the back surface of a support body.
The present invention can be applied to any of the lithographic printing plate precursors of the plate making method in which development is performed using a conventional developer after exposure and the plate making method in on-press development without using the developer.
Hereinafter, the lithographic printing plate precursor according to the invention will be sequentially described.

[Image Recording Layer Containing Microcapsule and Microgel]

[(A) Radical polymerizable compound]
The radical polymerizable compound used for the image recording layer in the present invention is an addition polymerizable compound having at least one ethylenically unsaturated double bond, and has at least one, preferably two or more terminal ethylenically unsaturated bonds. Selected from compounds. These have chemical forms such as monomers, prepolymers, ie dimers, trimers and oligomers, or mixtures thereof.

  Examples of monomers include unsaturated carboxylic acids (for example, acrylic acid, methacrylic acid, itaconic acid, crotonic acid, isocrotonic acid, maleic acid, etc.), esters and amides thereof, preferably unsaturated carboxylic acids. An ester of an acid and a polyhydric alcohol compound and an amide of an unsaturated carboxylic acid and a polyvalent amine compound are used. In addition, an addition reaction product of an unsaturated carboxylic acid ester or amide having a nucleophilic substituent such as a hydroxy group, an amino group or a mercapto group with a monofunctional or polyfunctional isocyanate or epoxy, and a monofunctional or polyfunctional compound. A dehydration condensation reaction product with a functional carboxylic acid is also preferably used. Further, an addition reaction product of an unsaturated carboxylic acid ester or amide having an electrophilic substituent such as an epoxy group or an epoxy group with a monofunctional or polyfunctional alcohol, amine or thiol, a halogen group or In addition, a substitution reaction product of an unsaturated carboxylic acid ester or amide having a leaving substituent such as a tosyloxy group and a monofunctional or polyfunctional alcohol, amine or thiol is also suitable.

  As another example, it is also possible to use a group of compounds substituted with unsaturated phosphonic acid, styrene, vinyl ether or the like instead of the unsaturated carboxylic acid. These are disclosed in JP-T-2006-508380, JP-A-2002-287344, JP-A-2008-256850, JP-A-2001-342222, JP-A-9-179296, JP-A-9-179297. JP-A-9-179298, JP-A-2004-294935, JP-A-2006-243493, JP-A-2002-275129, JP-A-2003-64130, JP-A-2003-280187, It is described in references including Kaihei 10-333321.

  Specific examples of a monomer of an ester of a polyhydric alcohol compound and an unsaturated carboxylic acid include acrylic acid esters such as ethylene glycol diacrylate, 1,3-butanediol diacrylate, tetramethylene glycol diacrylate, propylene glycol diacrylate, Examples include trimethylolpropane triacrylate, hexanediol diacrylate, tetraethylene glycol diacrylate, pentaerythritol tetraacrylate, sorbitol triacrylate, isocyanuric acid ethylene oxide (EO) -modified triacrylate, and polyester acrylate oligomer. Methacrylic acid esters include tetramethylene glycol dimethacrylate, neopentyl glycol dimethacrylate, trimethylolpropane trimethacrylate, ethylene glycol dimethacrylate, pentaerythritol trimethacrylate, bis [p- (3-methacryloxy-2-hydroxypropoxy) phenyl ] Dimethylmethane, bis- [p- (methacryloxyethoxy) phenyl] dimethylmethane, and the like. Specific examples of amide monomers of polyvalent amine compounds and unsaturated carboxylic acids include methylene bis-acrylamide, methylene bis-methacrylamide, 1,6-hexamethylene bis-acrylamide, 1,6-hexamethylene bis-methacrylic. Examples include amide, diethylenetriamine trisacrylamide, xylylene bisacrylamide, and xylylene bismethacrylamide.

In addition, urethane-based addition-polymerizable compounds produced by using an addition reaction between an isocyanate and a hydroxy group are also suitable, and specific examples thereof include, for example, one molecule described in Japanese Patent Publication No. 48-41708. A vinyl containing two or more polymerizable vinyl groups in one molecule obtained by adding a vinyl monomer containing a hydroxy group represented by the following general formula (d) to a polyisocyanate compound having two or more isocyanate groups. A urethane compound etc. are mentioned.
^{_{CH 2 = C (R 4)}} COOCH 2 CH (R 5) OH (d)
(However, R ⁴ and R ⁵ represent H or CH _3. )

  Also, urethanes described in JP-A-51-37193, JP-B-2-32293, JP-B-2-16765, JP-A-2003-344997, and JP-A-2006-65210. Acrylates, JP-B 58-49860, JP-B 56-17654, JP-B 62-39417, JP-B 62-39418, JP-A 2000-250211, JP-A 2007-94138 Urethane compounds having an ethylene oxide skeleton described in the publication, and hydrophilic groups described in US Pat. No. 7,153,632, JP-A-8-505958, JP-A-2007-293221, and JP-A-2007-293223. Also suitable are urethane compounds having.

  Among them, tris (acryloyloxyethyl) isocyanurate, bis (acryloyloxyethyl) hydroxyethyl isocyanurate, etc. are excellent in the balance between the hydrophilicity involved in on-press developability and the polymerization ability involved in printing durability. Isocyanuric acid ethylene oxide modified acrylates are particularly preferred.

  Details of the method of use such as the structure of these radically polymerizable compounds, whether they are used alone or in combination, and the amount added can be arbitrarily set in accordance with the performance design of the final lithographic printing plate precursor. The polymerizable compound is preferably used in the range of 5 to 75% by mass, more preferably 10 to 70% by mass, and particularly preferably 15 to 60% by mass with respect to the total solid content of the image recording layer.

[(B) Sensitizing dye]
The image recording layer of the present invention preferably contains a sensitizing dye. A sensitizing dye is particularly limited as long as it absorbs light at the time of image exposure and becomes excited, supplies energy to a polymerization initiator described later by electron transfer, energy transfer, or heat generation, and improves the polymerization initiation function. It can be used without. In particular, a sensitizing dye having a maximum absorption at 300 to 450 nm or 750 to 1400 nm is preferably used.

  Examples of the sensitizing dye having maximum absorption in the wavelength range of 350 to 450 nm include merocyanine dyes, benzopyrans, coumarins, aromatic ketones, anthracenes, styryls, oxazoles, and the like.

  Of the sensitizing dyes having an absorption maximum in the wavelength range of 360 nm to 450 nm, a dye more preferable from the viewpoint of high sensitivity is a dye represented by the following general formula (3).

(In General Formula (3), A represents an aryl group or a heteroaryl group which may have a substituent, and X represents an oxygen atom, a sulfur atom or N- (R ₃ ). R ₁ , R ₂ and R ₃ each independently represents a monovalent non-metallic atomic group, and A and R ₁ and R ₂ and R ₃ may be bonded to each other to form an aliphatic or aromatic ring. .)

General formula (3) will be described in more detail. R ₁ , R ₂ and R ₃ are each independently a monovalent nonmetallic atomic group, preferably a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group, substituted or unsubstituted An aryl group, a substituted or unsubstituted heteroaryl residue, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted alkylthio group, a hydroxy group, and a halogen atom.

  Specific examples of such a sensitizing dye include paragraph numbers [0047] to [0053] of JP-A No. 2007-58170, paragraph numbers [0036] to [0037] of JP-A No. 2007-93866, and JP-A No. 2007. And the compounds described in paragraph Nos. [0042] to [0047] of JP-A-72816.

  JP-A-2006-189604, JP-A-2007-171406, JP-A-2007-206216, JP-A-2007-206217, JP-A-2007-225701, JP-A-2007-225702, JP-A-2007-316582 The sensitizing dyes described in JP-A-2007-328243 are also preferably used.

  Subsequently, a sensitizing dye having a maximum absorption at 750 to 1400 nm that is preferably used in the present invention (hereinafter, sometimes referred to as “infrared absorber”) will be described in detail. As the infrared absorber, a dye or a pigment is preferably used.

As the dye, commercially available dyes and known dyes described in documents such as “Dye Handbook” (edited by the Society for Synthetic Organic Chemistry, published in 1970) can be used. Specifically, dyes such as azo dyes, metal complex azo dyes, pyrazolone azo dyes, naphthoquinone dyes, anthraquinone dyes, phthalocyanine dyes, carbonium dyes, quinoneimine dyes, methine dyes, cyanine dyes, squarylium dyes, pyrylium salts, metal thiolate complexes Is mentioned.
Particularly preferred among these dyes are cyanine dyes, squarylium dyes, pyrylium salts, nickel thiolate complexes, and indolenine cyanine dyes. Further, cyanine dyes and indolenine cyanine dyes are preferred, and particularly preferred examples include cyanine dyes represented by the following general formula (4).

In General Formula (4), X ¹ represents a hydrogen atom, a halogen atom, —N (R ⁹ ) (R ¹⁰ ), —X ² -L ¹ or a group shown below. Here, R ⁹ and R ¹⁰ may be the same or different, and may have a substituent, an aromatic hydrocarbon group having 6 to 10 carbon atoms, or an alkyl group having 1 to 8 carbon atoms. Represents a hydrogen atom, and R ⁹ and R ¹⁰ may be bonded to each other to form a ring. Of these, a phenyl group is preferred. X ² represents an oxygen atom or a sulfur atom, and L ¹ represents a hydrocarbon group having 1 to 12 carbon atoms, an aromatic ring having a hetero atom, or a hydrocarbon group having 1 to 12 carbon atoms including a hetero atom. . In addition, a hetero atom here shows N, S, O, a halogen atom, and Se. In the group shown below, Xa ^- has Za described later ^- is defined as for, R ^a represents a hydrogen atom, an alkyl group, an aryl group, a substituted or unsubstituted amino group, substituted or unsubstituted amino group and a halogen atom .

R ¹ and R ² each independently represents a hydrocarbon group having 1 to 12 carbon atoms. From the storage stability of the image recording layer coating solution, R ¹ and R ² are preferably hydrocarbon groups having 2 or more carbon atoms. R ¹ and R ² may be connected to each other to form a ring, and when forming a ring, it is particularly preferable to form a 5-membered ring or a 6-membered ring.

Ar ¹ and Ar ² may be the same or different and each represents an aryl group which may have a substituent. Preferred aryl groups include a benzene ring and a naphthalene ring. Moreover, as a preferable substituent, a C12 or less hydrocarbon group, a halogen atom, and a C12 or less alkoxy group are mentioned. Y ¹ and Y ² may be the same or different and each represents a sulfur atom or a dialkylmethylene group having 12 or less carbon atoms. R ³ and R ⁴ may be the same or different and each represents a hydrocarbon group having 20 or less carbon atoms which may have a substituent. Preferred substituents include alkoxy groups having 12 or less carbon atoms, carboxy groups, and sulfo groups. R ⁵ , R ⁶ , R ⁷ and R ⁸ may be the same or different and each represents a hydrogen atom or a hydrocarbon group having 12 or less carbon atoms. From the availability of raw materials, a hydrogen atom is preferred. Za ⁻ represents a counter anion. However, Za ⁻ is not necessary when the cyanine dye represented by the general formula (4) has an anionic substituent in its structure and neutralization of charge is not necessary. Preferred Za ⁻ is a halide ion, a perchlorate ion, a tetrafluoroborate ion, a hexafluorophosphate ion, and a sulfonate ion, particularly preferably a perchlorate ion, in view of the storage stability of the image recording layer coating solution. , Hexafluorophosphate ions, and aryl sulfonate ions. It is particularly preferable that the counter ion does not contain a halide ion.

  Specific examples of the cyanine dye represented by the general formula (4) that can be suitably used include paragraph numbers [0017] to [0019] of JP-A No. 2001-133969 and paragraph numbers of JP-A No. 2002-023360. [0016] to [0021], compounds described in paragraph numbers [0012] to [0037] of JP-A No. 2002-040638, preferably paragraph numbers [0034] to [0041] of JP-A No. 2002-278057 And compounds described in paragraph numbers [0080] to [0086] of JP-A-2008-195018, and most preferably compounds described in paragraph numbers [0035] to [0043] of JP-A-2007-90850. .

  In addition, compounds described in paragraph numbers [0008] to [0009] of JP-A No. 5-5005 and paragraph numbers [0022] to [0025] of JP-A No. 2001-222101 can also be preferably used.

  Moreover, only 1 type may be used for these infrared absorption dyes, and 2 or more types may be used together, and infrared absorbers other than infrared absorption dyes, such as a pigment, may be used together. As the pigment, compounds described in paragraph numbers [0072] to [0076] of JP-A-2008-195018 are preferable.

  The preferred addition amount of these sensitizing dyes is preferably 0.05 to 30 parts by mass, more preferably 0.1 to 20 parts by mass, and most preferably 0.2 to 100 parts by mass of the total solid content of the image recording layer. It is the range of -10 mass parts.

[(C) Photopolymerization initiator]
The image recording layer of the present invention can contain a known radical polymerization initiator. Examples of such radical polymerization initiators include (a) organic halides, (b) carbonyl compounds, (c) azo compounds, (d) organic peroxides, (e) metallocene compounds, and (f) azide compounds. (G) hexaarylbiimidazole compound, (h) organic borate compound, (i) disulfone compound, (j) oxime ester compound, (k) onium salt compound. Among these, sulfonium salts, iodonium salts, diazonium salts, azinium salts, oxime compounds, and triazine compounds can be given.
Specific examples thereof include the compounds described in JP-A-2008-195018.

  The radical polymerization initiator is preferably 0.1 to 50% by mass, more preferably 0.5 to 30% by mass, and particularly preferably 0.8 to 20% by mass with respect to the total solid content of the image recording layer. Can be added.

[(D) Microcapsule]
In order to improve the film strength of the image recording layer, the microcapsules obtained in the present invention are used for the image recording layer of the present invention. The content of the microcapsules in the image recording layer is preferably 5 to 80% by mass, more preferably 10 to 70% by mass, and particularly preferably 20 to 50% by mass. Within this range, better printing durability and developability can be obtained.
Since the microcapsules are used by being dispersed in an image recording layer coating solution containing an organic solvent as a solvent, the core component of the microcapsules is extracted outside the capsule in the coating solution, and the core component is contained in the image recording layer. It may be in the form of a missing microgel. The “microcapsule” of the present invention includes such a microgel form.

[(E) Binder polymer]
In the image recording layer of the present invention, a binder polymer can be used in order to improve the film strength of the image recording layer. As the binder polymer that can be used in the present invention, conventionally known binder polymers can be used without limitation, and polymers having film properties are preferred. Of these, acrylic resins, polyvinyl acetal resins, and polyurethane resins are preferable.

  Among them, as a binder polymer suitable for the present invention, as described in JP-A-2008-195018, a crosslinkable functional group for improving the film strength of the image portion is a main chain or a side chain, preferably a side chain. Have the following. Crosslinking is formed between the polymer molecules by the crosslinkable group, and curing is accelerated.

  The crosslinkable functional group is preferably an ethylenically unsaturated group such as a (meth) acryl group, vinyl group, allyl group, or styryl group, or an epoxy group, and these groups are introduced into the polymer by polymer reaction or copolymerization. be able to. For example, a reaction between an acrylic polymer or polyurethane having a carboxy group in the side chain and polyurethane and glycidyl methacrylate, or a reaction between a polymer having an epoxy group and an ethylenically unsaturated group-containing carboxylic acid such as methacrylic acid can be used.

  The content of the crosslinkable group in the binder polymer is preferably 0.1 to 10.0 mmol, more preferably 0.25 to 7.0 mmol, and most preferably 0.5 to 5.5 mmol per 1 g of the binder polymer. .

  In the present invention, the binder polymer preferably further has a hydrophilic group. The hydrophilic group contributes to imparting on-press developability to the image recording layer. In particular, the coexistence of the crosslinkable group and the hydrophilic group makes it possible to achieve both printing durability and developability.

  Examples of the hydrophilic group include a hydroxy group, a carboxy group, an alkylene oxide structure, an amino group, an ammonium group, an amide group, a sulfo group, and a phosphoric acid group. Among them, an alkylene oxide unit having 2 or 3 carbon atoms An alkylene oxide structure having 1 to 9 is preferable. In order to impart a hydrophilic group to the binder polymer, a monomer having a hydrophilic group may be copolymerized.

  In the present invention, a lipophilic group such as an alkyl group, an aryl group, an aralkyl group, and an alkenyl group can be introduced into the binder polymer in order to control the inking property. Specifically, a lipophilic group-containing monomer such as an alkyl methacrylate may be copolymerized.

  Specific examples (1) to (11) of the binder polymer used in the present invention are shown below, but the present invention is not limited thereto. The ratio of repeating units is a molar ratio.

  The binder polymer in the present invention preferably has a mass average molar mass (Mw) of 2000 or more, more preferably 5000 or more, and still more preferably 10,000 to 300,000.

[(F) Other ingredients]
The image recording layer of the present invention may further contain the following components as necessary.

(1) Low molecular weight hydrophilic compound The image-recording layer in the invention may contain a low molecular weight hydrophilic compound in order to improve the on-press developability without reducing the printing durability.
As the low molecular weight hydrophilic compound, for example, as the water-soluble organic compound, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol and the like glycols and ether or ester derivatives thereof, glycerin, Polyols such as pentaerythritol and tris (2-hydroxyethyl) isocyanurate, organic amines such as triethanolamine, diethanolamine and monoethanolamine and salts thereof, organic sulfones such as alkylsulfonic acid, toluenesulfonic acid and benzenesulfonic acid Acids and salts thereof, organic sulfamic acids such as alkylsulfamic acid and salts thereof, organic sulfuric acids such as alkylsulfuric acid and alkylethersulfuric acid and salts thereof, phenylphosphonic acid Organic phosphonic acids and salts thereof, tartaric acid, oxalic acid, citric acid, malic acid, lactic acid, gluconic acid, organic carboxylic acids and salts thereof such as amino acids, betaines, and the like.

  Among these, in the present invention, it is preferable to contain at least one selected from the group consisting of polyols, organic sulfates, organic sulfonates, and betaines.

  Specific examples of organic sulfonates include alkyl sulfonates such as sodium n-butyl sulfonate, sodium n-hexyl sulfonate, sodium 2-ethylhexyl sulfonate, sodium cyclohexyl sulfonate, and sodium n-octyl sulfonate. Sodium 5,8,11-trioxapentadecane-1-sulfonate, sodium 5,8,11-trioxaheptadecane-1-sulfonate, 13-ethyl-5,8,11-trioxaheptadecane-1; Alkyl sulfonates containing ethylene oxide chains such as sodium sulfonate, 5,8,11,14-tetraoxatetradecosane-1-sodium sulfonate; sodium benzenesulfonate, sodium p-toluenesulfonate, p-hydroxy Benzenesulfo Acid sodium, sodium p-styrenesulfonate, sodium dimethyl-5-sulfonate isophthalate, sodium 1-naphthylsulfonate, sodium 4-hydroxynaphthylsulfonate, disodium 1,5-naphthalenedisulfonate, 1,3,6 -Aryl sulfonates such as trisodium naphthalene trisulfonate, paragraph numbers [0026] to [0031] of JP 2007-276454 A, and paragraph numbers [0020] to [0047] of JP 2009-154525 A And the compounds described. The salt may be a potassium salt or a lithium salt.

  Organic sulfates include sulfates of alkyl, alkenyl, alkynyl, aryl or heterocyclic monoethers of polyethylene oxide. The number of ethylene oxide units is preferably 1 to 4, and the salt is preferably a sodium salt, potassium salt or lithium salt. Specific examples thereof include compounds described in paragraph numbers [0034] to [0038] of JP-A-2007-276454.

  As the betaines, compounds having 1 to 5 carbon atoms of the hydrocarbon substituent on the nitrogen atom are preferable. Specific examples include trimethylammonium acetate, dimethylpropylammonium acetate, 3-hydroxy-4-trimethyl. Ammonioobylate, 4- (1-pyridinio) butyrate, 1-hydroxyethyl-1-imidazolioacetate, trimethylammonium methanesulfonate, dimethylpropylammonium methanesulfonate, 3-trimethylammonio-1-propanesulfonate, Examples include 3- (1-pyridinio) -1-propanesulfonate.

  The above low molecular weight hydrophilic compound has a small hydrophobic part structure and almost no surface-active action, so that dampening water penetrates into the exposed part of the image recording layer (image part) and the hydrophobicity and film strength of the image part. Ink acceptability and printing durability of the image recording layer can be maintained satisfactorily.

The amount of these low molecular weight hydrophilic compounds added to the image recording layer is preferably 0.5% by mass or more and 20% by mass or less of the total solid content of the image recording layer. More preferably, they are 1 mass% or more and 15 mass% or less, More preferably, they are 2 mass% or more and 10 mass% or less. In this range, good on-press developability and printing durability can be obtained.
These compounds may be used alone or in combination of two or more.

(2) Grease Sensitizer In the image recording layer of the present invention, a lipid sensitizer such as a phosphonium compound, a nitrogen-containing low molecular weight compound, or an ammonium group-containing polymer is used for the image recording layer in order to improve the inking property. be able to. In particular, when an inorganic layered compound is contained in the protective layer, these compounds function as a surface coating agent for the inorganic layered compound, and prevent a decrease in the inking property during printing by the inorganic layered compound.

  Suitable phosphonium compounds include phosphonium compounds described in JP-A-2006-297907 and JP-A-2007-50660. Specific examples include tetrabutylphosphonium iodide, butyltriphenylphosphonium bromide, tetraphenylphosphonium bromide, 1,4-bis (triphenylphosphonio) butanedi (hexafluorophosphate), 1,7-bis (tri Phenylphosphonio) heptane sulfate, 1,9-bis (triphenylphosphonio) nonane = naphthalene-2,7-disulfonate, and the like.

  Examples of the nitrogen-containing low molecular weight compound include amine salts and quaternary ammonium salts. Also included are imidazolinium salts, benzoimidazolinium salts, pyridinium salts, and quinolinium salts. Of these, quaternary ammonium salts and pyridinium salts are preferable. Specific examples include tetramethylammonium = hexafluorophosphate, tetrabutylammonium = hexafluorophosphate, dodecyltrimethylammonium = p-toluenesulfonate, benzyltriethylammonium = hexafluorophosphate, benzyldimethyloctylammonium = hexafluorophosphate. Fert, benzyldimethyldodecyl ammonium = hexafluorophosphate, paragraph numbers [0021] to [0037] of JP-A-2008-284858, paragraph numbers [0030] to [0057] of JP-A-2009-90645 Compound etc. are mentioned.

  The ammonium group-containing polymer may be any polymer as long as it has an ammonium group in its structure, but a polymer containing 5 to 80 mol% of a (meth) acrylate having an ammonium group in the side chain as a copolymerization component is preferable. . Specific examples include the polymers described in paragraph numbers [0089] to [0105] of JP2009-208458A.

  The ammonium salt-containing polymer has a reduced specific viscosity (unit: ml / g) determined by the following measurement method, preferably in the range of 5 to 120, more preferably in the range of 10 to 110, 15 Those in the range of ~ 100 are particularly preferred. When the said reduced specific viscosity is converted into a mass mean molar mass (Mw), 10,000-150,000 are preferable, 17000-140000 are more preferable, 20000-130000 are especially preferable.

<Measurement method of reduced specific viscosity>
Weigh 3.33 g of 30% polymer solution (1 g as solid content) into a 20 ml volumetric flask and make up with N-methylpyrrolidone. This solution is allowed to stand for 30 minutes in a thermostatic bath at 30 ° C., put in an Ubbelohde reduced viscosity tube (viscosity constant = 0.010 cSt / s), and the time for flowing down at 30 ° C. is measured. The measurement is performed twice with the same sample, and the average value is calculated. Similarly, in the case of a blank (only N-methylpyrrolidone), the reduced specific viscosity (ml / g) was calculated from the following formula.

Specific examples of the ammonium group-containing polymer are shown below.
(1) 2- (Trimethylammonio) ethyl methacrylate = p-toluenesulfonate / 3,6-dioxaheptyl methacrylate copolymer (molar ratio 10/90 Mw 45,000)
(2) 2- (Trimethylammonio) ethyl methacrylate = hexafluorophosphate / 3,6-dioxaheptyl methacrylate copolymer (molar ratio 20/80 Mw 60,000)
(3) 2- (Ethyldimethylammonio) ethyl methacrylate = p-toluenesulfonate / hexyl methacrylate copolymer (molar ratio 30/70 Mw 45,000)
(4) 2- (Trimethylammonio) ethyl methacrylate = hexafluorophosphate / 2-ethylhexyl methacrylate copolymer (molar ratio 20/80 Mw 60,000)
(5) 2- (Trimethylammonio) ethyl methacrylate = methyl sulfate / hexyl methacrylate copolymer (molar ratio 40/60 Mw 7 million)
(6) 2- (Butyldimethylammonio) ethyl methacrylate = hexafluorophosphate / 3,6-dioxaheptyl methacrylate copolymer (molar ratio 25/75 Mw 650,000)
(7) 2- (Butyldimethylammonio) ethyl acrylate = hexafluorophosphate / 3,6-dioxaheptyl methacrylate copolymer (molar ratio 20/80 Mw 65,000)
(8) 2- (butyldimethylammonio) ethyl methacrylate = 13-ethyl-5,8,11-trioxa-1-heptadecanesulfonate / 3,6-dioxaheptyl methacrylate copolymer (molar ratio 20/80 Mw 75,000)
(9) 2- (butyldimethylammonio) ethyl methacrylate = hexafluorophosphate / 3,6-dioxaheptyl methacrylate / 2-hydroxy-3-methacryloyloxypropyl methacrylate copolymer (molar ratio 15/80/5 (Mw 650,000)

  The content of the sensitizer is preferably from 0.01 to 30.0% by mass, more preferably from 0.1 to 15.0% by mass, based on the total solid content of the image recording layer. More preferred is mass%.

(3) Others Further, as other components, surfactants, colorants, baking-out agents, polymerization inhibitors, higher fatty acid derivatives, plasticizers, inorganic fine particles, inorganic layered compounds, sensitizing aids or chain transfer agents, etc. Can be added. Specifically, paragraph numbers [0114] to [0159] of Japanese Patent Application Laid-Open No. 2008-284817, paragraph numbers [0023] to [0027] of Japanese Patent Application Laid-Open No. 2006-091479, and US Patent Publication No. 2008/0311520. The compound and the addition amount described in paragraph [0060] of FIG.

(Formation of image recording layer)
The image recording layer in the present invention is a coating solution prepared by dispersing or dissolving the necessary components in a known solvent as described in paragraphs [0142] to [0143] of JP-A-2008-195018, for example. This is prepared by coating the substrate by a known method such as bar coater coating and drying. The image recording layer coating amount (solid content) on the support obtained after coating and drying varies depending on the application, but is generally preferably 0.3 to 3.0 g / m ² . Within this range, good sensitivity and good film characteristics of the image recording layer can be obtained.

[Undercoat layer]
In the lithographic printing plate precursor according to the invention, an undercoat layer (sometimes referred to as an intermediate layer) is preferably provided between the image recording layer and the support. The undercoat layer enhances the adhesion between the support and the image recording layer in the exposed area, and easily peels off the image recording layer from the support in the unexposed area. Contributes to improvement. In the case of infrared laser exposure, the undercoat layer functions as a heat insulating layer, thereby preventing the heat generated by the exposure from diffusing to the support and reducing the sensitivity.

  As the compound used for the undercoat layer, an undercoat layer having a compound having an acid group such as phosphonic acid, phosphoric acid, or sulfonic acid is preferably used. Further, those having an adsorbing group capable of being adsorbed on the surface of the support and a crosslinkable group in order to improve adhesion to the image recording layer are preferable. These compounds may be low molecular weight or high molecular weight polymers. Moreover, you may use these compounds in mixture of 2 or more types as needed.

In the case of a high molecular polymer, a copolymer of a monomer having an adsorptive group, a monomer having a hydrophilic group, and a monomer having a crosslinkable group is preferable. The adsorbable adsorptive group to the surface of the support, a phenolic hydroxy group, a carboxy _{group, -PO 3 H 2, -OPO 3} H 2, -CONHSO 2 -, - SO 2 NHSO 2 -, - COCH 2 COCH 3 Is preferred. As the hydrophilic group, a sulfo group is preferable. The crosslinkable group is preferably a methacryl group or an allyl group. This polymer may have a crosslinkable group introduced by salt formation between the polar substituent of the polymer, a substituent having a counter charge and a compound having an ethylenically unsaturated bond, Other monomers, preferably hydrophilic monomers, may be further copolymerized.
Specifically, a silane coupling agent having an addition-polymerizable ethylenic double bond reactive group described in JP-A-10-282679 and an ethylenic compound described in JP-A-2-304441. The phosphorus compound which has a heavy bond reactive group is mentioned suitably. Crosslinkable groups (preferably ethylenically unsaturated bond groups) described in JP-A-2005-238816, JP-A-2005-12549, JP-A-2006-239867, and JP-A-2006-215263, the surface of the support Those containing a low-molecular or high-molecular compound having a functional group that interacts with each other and a hydrophilic group are also preferably used. More preferable are polymer polymers having an adsorbable group, a hydrophilic group, and a crosslinkable group that can be adsorbed on the support surface described in JP-A Nos. 2005-125749 and 2006-188038.

The content of unsaturated double bonds in the polymer resin for the undercoat layer is preferably 0.1 to 10.0 mmol, and most preferably 0.2 to 5.5 mmol per 1 g of the polymer.
The polymer for the undercoat layer preferably has a mass average molar mass of 5000 or more, more preferably 10,000 to 300,000.

  The undercoat layer of the present invention comprises, in addition to the above undercoat compound, a chelating agent, a secondary or tertiary amine, a polymerization inhibitor, an amino group, or a functional group having a polymerization inhibiting ability, in order to prevent contamination over time. Compounds having a group that interacts with the surface of an aluminum support (for example, 1,4-diazabicyclo [2,2,2] octane (DABCO), 2,3,5,6-tetrahydroxy-p-quinone, chloranil , Sulfophthalic acid, hydroxyethylethylenediaminetriacetic acid, dihydroxyethylethylenediaminediacetic acid, hydroxyethyliminodiacetic acid, and the like.

The undercoat layer is applied by a known method. The coating amount (solid content) of the undercoat layer is preferably from 0.1-100 mg / m ^2, and more preferably 1 to 30 mg / m ^2.

[Support]
As the support used in the lithographic printing plate precursor according to the invention, a known support is used. Of these, an aluminum plate that has been roughened and anodized by a known method is preferred.
In addition, the above aluminum plate is optionally subjected to micropore enlargement treatment or sealing treatment of an anodized film described in JP-A Nos. 2001-253181 and 2001-322365, and US Pat. 714,066, 3,181,461, 3,280,734 and 3,902,734, or alkali metal silicates as described in U.S. Pat. Surface hydrophilization treatment with polyvinylphosphonic acid or the like as described in each specification of 3,276,868, 4,153,461 and 4,689,272 is appropriately performed and performed. be able to.
The support preferably has a center line average roughness of 0.10 to 1.2 μm.

  If necessary, the support of the present invention includes an organic polymer compound described in JP-A-5-45885 and a silicon alkoxy compound described in JP-A-6-35174 on the back surface. A backcoat layer can be provided.

[Protective layer]
In the lithographic printing plate precursor according to the invention, a protective layer (overcoat layer) is preferably provided on the image recording layer. In addition to the function of suppressing the image formation inhibition reaction by blocking oxygen, the protective layer has a function of preventing scratches in the image recording layer and preventing ablation during high-illuminance laser exposure.

The protective layer having such characteristics is described in, for example, US Pat. No. 3,458,311 and Japanese Patent Publication No. 55-49729. As the low oxygen permeability polymer used for the protective layer, either a water-soluble polymer or a water-insoluble polymer can be appropriately selected and used, and two or more types can be mixed and used as necessary. it can. Specific examples include polyvinyl alcohol, modified polyvinyl alcohol, polyvinyl pyrrolidone, water-soluble cellulose derivatives, poly (meth) acrylonitrile, and the like.
As the modified polyvinyl alcohol, acid-modified polyvinyl alcohol having a carboxy group or a sulfo group is preferably used. Specifically, modified polyvinyl alcohols described in JP-A-2005-250216 and JP-A-2006-259137 are suitable.

Further, in order to enhance the oxygen barrier property, the protective layer preferably contains an inorganic layered compound such as natural mica and synthetic mica as described in JP-A-2005-119273.
Further, the protective layer may contain known additives such as a plasticizer for imparting flexibility, a surfactant for improving coating properties, and inorganic fine particles for controlling surface slipperiness. Further, the protective layer can contain the sensitizer described in the description of the image recording layer.

The protective layer is applied by a known method. The coating amount of the protective layer, the coating amount after drying is preferably in the range of 0.01 to 10 g / ^{m 2,} more preferably in the range of 0.02 to 3 g / ^{m 2,} and most preferably 0. in the range of 02~1g / ^{m 2.}

  In addition, adhesion to the image area and scratch resistance are also extremely important in handling the plate. That is, when a hydrophilic layer made of a water-soluble polymer is laminated on an oleophilic polymer layer, film peeling due to insufficient adhesion tends to occur, and the peeled portion causes defects such as poor film hardening due to inhibition of oxygen polymerization. On the other hand, various proposals have been made to improve the adhesion between these two layers. For example, Japanese Patent Publication No. 54-12215 and British Patent Application No. 1303578 disclose an acrylic emulsion or a water-insoluble vinylpyrrolidone-vinyl acetate copolymer in a hydrophilic polymer mainly composed of polyvinyl alcohol. It is described that sufficient adhesiveness can be obtained by mixing ˜60 mass% and laminating on the polymerized layer. Any of these known techniques can be applied to the protective layer in the present invention. Such a coating method for the protective layer is described in detail in, for example, US Pat. No. 3,458,311 and Japanese Patent Publication No. 55-49729.

[Plate making method]
The lithographic printing plate precursor according to the present invention is subjected to development in a development processing step after exposure, and then subjected to printing, or is supplied with printing ink and a fountain solution without passing through the development processing step. Then, it is used for printing as it is. Hereinafter, the plate making method of the present invention will be described in detail.

〔exposure〕
The lithographic printing plate precursor according to the present invention is imagewise exposed by laser exposure through a transparent original image having a line image, a halftone dot image or the like, or by laser beam scanning by digital data.
The wavelength of the light source is preferably 300 to 450 nm or 750 to 1400 nm. In the case of a light source of 300 to 450 nm, a lithographic printing plate precursor containing a sensitizing dye having an absorption maximum in this wavelength region in the image recording layer is preferably used, and in the case of a light source of 750 to 1400 nm, it absorbs in this wavelength region. A lithographic printing plate precursor containing an infrared absorbing agent, which is a sensitizing dye having a colorant, in an image recording layer is preferably used. As the light source of 300 to 450 nm, a semiconductor laser is suitable. As a light source of 750 to 1400 nm, a solid laser and a semiconductor laser emitting infrared rays are suitable. Regarding the infrared laser, the output is preferably 100 mW or more, the exposure time per pixel is preferably within 20 microseconds, and the irradiation energy amount is preferably 10 to 300 mJ / cm ² . In order to shorten the exposure time, it is preferable to use a multi-beam laser device. The exposure mechanism may be any of an internal drum system, an external drum system, a flat bed system, and the like.
Image exposure can be performed by a conventional method using a plate setter or the like. In the case of on-press development, the lithographic printing plate precursor may be mounted on a printing press and then image exposure may be performed on the printing press.

[Development processing]
The development processing of the lithographic printing plate precursor according to the invention can be performed by a known method. A known developer composed of an aqueous solution containing a component selected from a surfactant, an organic solvent, an alkali agent, a water-soluble polymer compound, a preservative, a chelate compound, an antifoaming agent, an organic acid, an inorganic acid, an inorganic salt, and the like. Used. An aqueous solution having a pH of less than 10 can also be used. In this case, a developer containing a surfactant and / or a water-soluble resin is preferable. Usually, a desensitizing solution for protecting the plate after developing the lithographic printing plate precursor can also be used as a developing solution.
In the present invention, the lithographic printing plate after the development treatment can optionally be subsequently washed with water, dried and desensitized. In the desensitizing treatment, a known desensitizing solution can be used.

  The lithographic printing plate obtained by carrying out the above development processing is placed on an offset printing machine and used for printing a large number of sheets.

[On-machine development]
The exposed lithographic printing plate precursor is mounted on a plate cylinder of a printing press. In the case of a printing press equipped with a laser exposure device, imagewise exposure is performed after a lithographic printing plate precursor is mounted on the plate cylinder of the printing press.

  After the lithographic printing plate precursor is exposed imagewise with an infrared laser or the like, printing is performed by supplying printing ink and fountain solution without going through a development process such as a wet development process, and the like in the exposed part of the image recording layer. The image recording layer cured by exposure forms a printing ink receiving portion having an oleophilic surface. On the other hand, in the unexposed area, the uncured image recording layer is removed by dissolution or dispersion by the supplied dampening water and / or printing ink, and a hydrophilic surface is exposed in that area. As a result, the fountain solution adheres to the exposed hydrophilic surface, and the printing ink is deposited on the image recording layer in the exposed area and printing is started.

Here, the fountain solution or the printing ink may be supplied to the printing plate first, but the printing ink is first used in order to prevent the fountain solution from being contaminated by the removed components of the image recording layer. Is preferably supplied. As the fountain solution and printing ink, normal lithographic fountain solution and printing ink are used.
In this way, the lithographic printing plate precursor is developed on an offset printing machine and used as it is for printing a large number of sheets.

  EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited to these. In the polymer compound, the molecular weight is a mass average molar mass (Mw), and the ratio of repeating units is a mole percentage, except for those specifically defined.

[Production of microcapsules]

[Synthesis Example of Isocyanate Adduct (NCO-1 to 12)]

(Synthesis Example 1: Synthesis of NCO-1)
In a suspension of ethyl acetate (470.7 g) of 355.6 g (1.60 mol) of isophorone diisocyanate (IPDI) and 169.6 g (0.40 mol) of a polyphenol compound (P-2, the following structure), A solution prepared by dissolving 471 mg of stannous octylate (Stanocto, manufactured by Yoshitomi Pharmaceutical Co., Ltd.) in 10 g of ethyl acetate was added dropwise over 1 hour with stirring. After dropping, stirring was continued for 2 hours, and then stirring was performed at 50 ° C. for 3 hours. In this way, a solution (concentration 50% by mass) of an isocyanate adduct (NCO-1) was obtained.

  It was Mw = 2700 when the terminal isocyanate body obtained by the said reaction was inactivated with dibutylamine and the molecular weight (polystyrene conversion value) was measured.

(Synthesis Examples 2 to 8: Synthesis of NCO-2 to 8)
In Synthesis Example 1, P-2 was changed to the polyhydric phenol compound shown in Table 1 below, and the same method as in Synthesis Example 1 except that the ratio with isophorone diisocyanate (IPDI) was changed to the values shown in Table 1. To obtain a solution of an isocyanate adduct (NCO-2 to 8).

(Synthesis Examples 9-12: Synthesis of NCO-9-12)
A solution of an isocyanate adduct (NCO-9 to 12) was obtained in the same manner as in Synthesis Example 1 except that isophorone diisocyanate (IPDI) was changed to the polyfunctional isocyanate compound shown in Table 2 below in Synthesis Example 1. .

[Production example of microcapsule]

(Preparation of microcapsule (CP-1))
As an oil phase component, 8 g of the above-mentioned isocyanate adduct (NCO-1) solution, trimethylolpropane (6 mol) and xylene diisocyanate (18 mol) were added, and methyl one-end polyoxyethylene (1 mol, still oxy) was added thereto. 2 g of adduct (Mitsui Chemicals, Inc .; 50% by mass ethyl acetate solution) to which an ethylene unit repeat number of 90) was added, 3.15 g of pentaerythritol triacrylate (manufactured by Nippon Kayaku Co., Ltd., SR444), Triphenylphosphine (1.0 mmol) 0.27 g and surfactant Pionein A-41C (manufactured by Takemoto Yushi Co., Ltd.) 0.1 g were dissolved in 17 g of ethyl acetate. As an aqueous phase component, 40 g of a 4% by mass aqueous solution of polyvinyl alcohol (PVA-205 manufactured by Kuraray Co., Ltd.) was prepared. The oil phase component and the aqueous phase component were mixed and emulsified for 10 minutes at 12,000 rpm using a homogenizer. The obtained emulsion was added to 25 g of distilled water and stirred at 40 ° C. for 4 hours. The microgel solution thus obtained was diluted with distilled water to a solid content concentration of 15% by mass to obtain microcapsules (CP-1). When the average particle size of the microcapsules was measured by a light scattering method, the average particle size was 0.2 μm.

(Synthesis of microcapsule (CP-2))
In the synthesis of the microcapsule (CP-1), the microcapsule (CP-2) was prepared by the same method as the synthesis of the microcapsule (CP-1) except that triphenylphosphine was changed to triphenylphosphite. Obtained.

(Synthesis of microcapsule (CP-3))
In the synthesis of the microcapsule (CP-1), the microcapsule (CP-3) was prepared by the same method as the synthesis of the microcapsule (CP-1) except that triphenylphosphine was changed to trilauryl thiophosphite. Got.

(Synthesis of microcapsules (CP-4) to (CP-14))
In the synthesis of the microcapsule (CP-1), except that the solution of the isocyanate adduct (NCO-1) was changed to a 50 mass% ethyl acetate solution of the polyfunctional isocyanate (NCO-2 to 12) in Table 3, Microcapsules (CP-4) to (CP-14) were obtained by the same method as the synthesis of microcapsules (CP-1).

(Synthesis of microcapsule (CP-15))
In the synthesis of the microcapsule (CP-1), a comparative microcapsule (CP-15) was obtained by the same method as the synthesis of the microcapsule (CP-1) except that triphenylphosphine was not added. .

(Synthesis of microcapsule (CP-16))
In the synthesis of the microcapsule (CP-10), a comparative microcapsule (CP-16) was obtained by the same method as the synthesis of the microcapsule (CP-10) except that triphenylphosphine was not added. .

(Measurement of NCO residual rate)
With respect to the microcapsules synthesized as described above, the amount of unreacted isocyanate groups was measured by the following infrared absorption spectrum measurement method. Table 3 shows the measurement results.

(1) Sample preparation method The microcapsule dispersion was dried at 40 ° C. under reduced pressure for 4 hours to obtain a white powder of microcapsules. 3 mg of the obtained white powder and 150 mg of KBr were mixed to prepare KBr pellets of microcapsule powder.

(2) IR measurement (KBr method)
An IR spectrum (manufactured by VARIAN: FTS 3000, manufactured by Agilent) was measured using the KBr pellets of the obtained microcapsules. In the obtained IR spectrum, the peak intensity at 2260 cm ⁻¹ derived from the peak of the isocyanato group was normalized with the peak intensity at 810 cm ⁻¹ (peak derived from the core substance), and the remaining amount of the isocyanate group was calculated from the following formula. The following formula was derived from the peak intensity of 2260 cm ⁻¹ obtained from the IR spectrum of the isocyanate adduct prior to the microencapsulation reaction.

<NCO (isocyanato) group residual ratio calculation formula>
NCO group remaining ratio = standard value (the peak intensity of the peak intensity ÷ 810 cm ^-1 of the ^{2260cm -1) × 0.108 ÷ 1.84 ×} 100

  As is clear from the results of Table 3, in the case of the microcapsules of the comparative example not containing a trivalent phosphorus compound, the microencapsulation reaction is slow and 10 to 20% of isocyanate groups remain.

[Examples 1 to 16] (lithographic printing plate precursor for alkali development)

1. Production of support (1)
In order to remove rolling oil on the surface of an aluminum plate (material JIS A 1050) having a thickness of 0.3 mm, a degreasing treatment was performed at 50 ° C. for 30 seconds using a 10 mass% sodium aluminate aqueous solution, and then the hair diameter was adjusted to 0. The aluminum surface was grained using ^three 3 mm bundled nylon brushes and a pumice-water suspension (specific gravity 1.1 g / cm ³ ) having a median diameter of 25 μm and washed well with water. This plate was etched by being immersed in a 25 mass% aqueous sodium hydroxide solution at 45 ° C for 9 seconds, washed with water, further immersed in a 20 mass% nitric acid aqueous solution at 60 ° C for 20 seconds, and washed with water. The etching amount of the grained surface at this time was about 3 g / m ² .

Next, an electrochemical roughening treatment was performed continuously using an alternating voltage of 60 Hz. The electrolytic solution at this time was a 1% by mass nitric acid aqueous solution (containing 0.5% by mass of aluminum ions) and a liquid temperature of 50 ° C. The AC power source waveform is electrochemical roughening treatment using a trapezoidal rectangular wave alternating current with a time ratio TP of 0.8 msec until the current value reaches a peak from zero, a duty ratio of 1: 1, and a trapezoidal rectangular wave alternating current. Went. Ferrite was used for the auxiliary anode. The current density was 30 A / dm ² at the peak current value, and 5% of the current flowing from the power source was shunted to the auxiliary anode. The amount of electricity in nitric acid electrolysis was 175 C / dm ² when the aluminum plate was the anode. Then, water washing by spraying was performed.

Subsequently, nitric acid electrolysis was performed with an aqueous solution of 0.5% by mass of hydrochloric acid (containing 0.5% by mass of aluminum ions) and an electrolytic solution having a liquid temperature of 50 ° C. under the condition of an electric quantity of 50 C / dm ² when the aluminum plate was the anode. In the same manner as above, an electrochemical surface roughening treatment was performed, followed by washing with water by spraying.
Next, a 2.5 g / m ² direct current anodic oxide film with a current density of 15 A / dm ² is provided on the plate as an electrolyte using a 15% by weight sulfuric acid (containing 0.5% by weight aluminum ion) solution, followed by washing with water. And dried to prepare a support (1). The centerline average roughness (Ra) of this substrate was measured using a needle having a diameter of 2 μm and found to be 0.51 μm.

2. Application of Undercoat Layer Next, the following undercoat layer coating solution (1) was applied onto the support (1) with a wire bar and dried at 100 ° C. for 10 seconds. The coating amount was 10 mg / m ² .

-Undercoat layer coating solution (1)-
-Polymer compound A having the following structure: 0.05 g
・ Methanol 27g
・ Ion exchange water 3g

3. Application of Image Recording Layer An image recording layer coating solution (1) having the following composition was prepared and applied onto the undercoat layer using a wire bar so that the coating amount after drying was 0.9 g / m ^2. Then, the image recording layer was formed by drying at 115 ° C. for 34 seconds using a hot air drying apparatus.

-Coating liquid for image recording layer (1)-
・ Microcapsule (described in Table 4) 4.568 g
Infrared absorbing dye (IR pigment) (described in Table 4) 0.038 g
-Radical polymerization initiator A (S-1 having the following structure) 0.061 g
-Radical polymerization initiator B (I-1 having the following structure) 0.094 g
・ Mercapto compound (SH-1 having the following structure) 0.015 g
-Sensitization aid (T-1 having the following structure) 0.081 g
Addition polymerizable compound (M-1 having the following structure) 0.428 g
-Binder polymer A (B-1 having the following structure) 0.311 g
-Binder polymer B (B-2 having the following structure) 0.250 g
・ Binder polymer C (B-3 having the following structure) 0.062 g
-Polymerization inhibitor (Q-1 having the following structure) 0.0012 g
-Copper phthalocyanine pigment dispersion (the following composition) 0.159g
・ Fluorine surfactant 0.0081g
(Megafuck F-780-F Dainippon Ink and Chemicals,
Methyl isobutyl ketone (MIBK) 30% by mass solution)
・ Methyl ethyl ketone 5.886g
・ Methanol 2.733g
・ 1-methoxy-2-propanol 5.886 g

[Composition of copper phthalocyanine pigment dispersion]
Copper phthalocyanine pigment: 15 parts by mass, allyl methacrylate / methacrylic acid (80/20) copolymer as a dispersant: 10 parts by mass, cyclohexanone / methoxypropyl acetate / 1-methoxy-2-propanol = 15 parts by mass / 20 as a solvent Parts by mass / 40 parts by mass

4). Coating of protective layer <Lower protective layer>
Synthetic mica (Somasif MEB-3L, 3.2% aqueous dispersion, manufactured by Coop Chemical Co., Ltd.), polyvinyl alcohol (Goselan CKS-50: saponification degree 99 mol%, polymerization degree 300, sulfonic acid on the surface of the image recording layer Modified polyvinyl alcohol, manufactured by Nippon Synthetic Chemical Industry Co., Ltd.), surfactant A (manufactured by Nippon Emulsion Co., Emalex 710) and surfactant B (Adeka Pluronic P-84: manufactured by Asahi Denka Kogyo Co., Ltd.) An aqueous solution (a coating solution for a protective layer) was applied with a wire bar, and dried at 125 ° C. for 30 seconds with a hot air drying apparatus.
The content ratio of synthetic mica (solid content) / polyvinyl alcohol / surfactant A / surfactant B in the mixed aqueous solution (coating liquid for protective layer) was 7.5 / 89/2 / 1.5 (mass). The coating amount (the coating amount after drying) was 0.5 g / m ² .

<Upper protective layer>
On the surface of the lower protective layer, an organic filler (Art Pearl J-7P, manufactured by Negami Industrial Co., Ltd.), synthetic mica (Somasif MEB-3L, 3.2% aqueous dispersion, manufactured by Coop Chemical Co., Ltd.), polyvinyl alcohol ( L-3266: degree of saponification 87 mol%, degree of polymerization 300, sulfonic acid-modified polyvinyl alcohol, manufactured by Nippon Synthetic Chemical Industry Co., Ltd.), thickener (Serogen FS-B, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.), the above A mixed aqueous solution (protective layer coating solution) of polymer compound A and a surfactant (manufactured by Nippon Emulsion Co., Ltd.) is applied with a wire bar and dried at 125 ° C. for 30 seconds in a hot air dryer. It was.
The content ratio of the organic filler / synthetic mica (solid content) / polyvinyl alcohol / thickener / polymer compound A / surfactant in the mixed aqueous solution (protective layer coating solution) is 4.7 / 2.8. /67.4/18.6/2.3/4.2 (mass%), and the coating amount (the coating amount after drying) was 1.8 g / m ² .
In this way, lithographic printing plate precursors of Examples 1 to 16 were obtained.

[Comparative Examples 1-3]
In Example 1, the planographic printing plate precursors of Comparative Examples 1 to 3 were obtained in the same manner as in Example 1 except that the microcapsules were changed as shown in Table 4 below.

[Comparative Examples 4 to 5]
In Example 1, except that 33 mg of triphenylphosphine was added at the time of preparing the image recording layer coating solution (1) and the microcapsules were changed as shown in Table 4 below, the same method as in Example 1 was used. The planographic printing plate precursors of Comparative Examples 4 to 5 were obtained.

[Evaluation of planographic printing plate precursor]
(1) Sensitivity evaluation The obtained lithographic printing plate precursor was subjected to a Creo Trendsetter 3244VX equipped with a water-cooled 40 W infrared semiconductor laser, with a resolution of 175 lpi, an outer drum rotation speed of 150 rpm, and an output of 0 to 8 W of 0. The exposure was changed by 15 steps. The exposure was performed under conditions of 25 ° C. and 50% RH. After the exposure, development was performed at 30 ° C. for 12 seconds using a processor LP-1310News manufactured by FUJIFILM Corporation. The developer used was a 1: 4 water diluted water of DH-N manufactured by Fuji Film Co., Ltd., and the 1: 1 water diluted solution of GN-2K manufactured by Fuji Film Co., Ltd. was used as the finisher.
The density of the image area of the lithographic printing plate obtained by development was measured using a Macbeth reflection densitometer RD-918 and the cyan density using a red filter equipped in the densitometer. The reciprocal of the exposure necessary to obtain a measured density of 0.8 was used as an index of sensitivity. The evaluation results were such that the sensitivity of the lithographic printing plate precursor obtained in Comparative Example 1 was 100, and the sensitivity of other lithographic printing plate precursors was a relative evaluation thereof. The larger the value, the better the sensitivity. The results are shown in Table 4.

(2) Printing durability evaluation and dirt evaluation An 80% flat screen image with a resolution of 175 lpi was output to the produced lithographic printing plate precursor using a water-cooled 40 W infrared semiconductor laser and a 175 lpi 80% flat screen image with an output of 8 W and an external drum. The exposure was performed at a rotation speed of 206 rpm and a plate surface energy of 100 mJ / cm ² . After the exposure, the protective layer was removed by rinsing with tap water, and then developed by the same method as in (1) Sensitivity evaluation development step. The obtained lithographic printing plate is printed using a printing press Lislon manufactured by Komori Corporation, and the printed matter in the image area is observed. It was used as an index. The printing stain resistance was printed on 1000 sheets, and the ink stain on the non-image area was visually evaluated. The results are shown in Table 4.

(3) Storage stability evaluation After the lithographic printing plate precursor was forcibly aged at 60 ° C. and 75% RH for 4 days, a lithographic printing plate was prepared in the same manner as described above, and the printing was performed in the same manner as that not aged. The same soiling evaluation was performed. The results are shown in Table 4.

As is clear from Table 4, the lithographic printing plate precursors (Examples 1 to 16) using the microcapsules of the present invention were more resistant to stains than the lithographic printing plate precursors not containing the microcapsules of the present invention. There was an improvement in both printing durability.
Moreover, compared with the lithographic printing plate precursor using the conventional microcapsules not containing the phosphorus compound of the present invention (Comparative Examples 2 to 3), the lithographic printing plate precursor using the microcapsules of the present invention (Example 1) -16) is excellent in dirtiness after forced aging (after 60 days at 60 ° C. and 75% RH). Further, even if a phosphorus compound is added later (Comparative Examples 4 to 5), the soiling property after forced aging (after 60 ° C. and 75% RH for 4 days) is inferior, and the effect cannot be obtained.

[Examples 17 to 32] (On-press development type lithographic printing plate precursor)

(1) Production of support (2)
In order to ensure the hydrophilicity of the non-image area, the support (1) was subjected to a silicate treatment at 60 ° C. for 10 seconds using a 2.5 mass% No. 3 sodium silicate aqueous solution, and then washed with water. (2) was obtained. The adhesion amount of Si was 10 mg / m ² .

(2) Formation of undercoat layer Next, on the support (2), the following undercoat layer coating solution (2) was applied so that the dry coating amount was 20 mg / m ² , and a support having an undercoat layer. Was made.

<Coating liquid for undercoat layer (2)>
・ Polymer compound B 0.18 g having the following structure
・ Hydroxyethyliminodiacetic acid 0.10g
・ Methanol 55.24g
・ Water 6.15g

(3) Formation of image recording layer After the bar coating of the image recording layer coating liquid (2) having the following composition is applied on the undercoat layer formed as described above, it is oven-dried at 100 ° C for 60 seconds, and the dry coating amount An image recording layer of 1.0 g / m ² was formed.
The image recording layer coating solution (2) was obtained by mixing and stirring the following photosensitive solution (1) and microcapsule solution (1) immediately before coating.

<Photosensitive solution (1)>
-Binder polymer (1) [the following structure] 0.240 g
Infrared absorbing dye (IR dye) [Type: listed in Table 5] 0.030 g
-Radical polymerization initiator (1) [the following structure] 0.162 g
-Radical polymerizable compound Tris (acryloyloxyethyl) isocyanurate (NK ester A-9300, manufactured by Shin-Nakamura Chemical Co., Ltd.) 0.192 g
・ Low molecular weight hydrophilic compound Tris (2-hydroxyethyl) isocyanurate 0.062g
・ Low molecular weight hydrophilic compound (1) [the following structure] 0.050 g
-Sensitizing agent Phosphonium compound (1) [the following structure] 0.055 g
・ Sensitizer Benzyl-dimethyl-octylammonium ・ PF ₆ salt 0.018g
-Sensitizing agent Ammonium group-containing polymer [the following structure, reduced specific viscosity 44 g / ml] 0.035 g
・ Fluorosurfactant (1) [The following structure] 0.008g
・ 2-butanone 1.091g
・ 1-methoxy-2-propanol 8.609g

<Microcapsule solution (1)>
・ Microcapsules [Type: listed in Table 5] 2.640 g
・ Distilled water 2.425g

  Structures of binder polymer (1), radical polymerization initiator (1), phosphonium compound (1), low molecular weight hydrophilic compound (1), ammonium group-containing polymer, and fluorine-based surfactant (1) used in the above formulation Is as follows.

(3) Formation of Protective Layer After the bar coating of the protective layer coating solution (1) having the following composition was applied on the image recording layer, it was oven-dried at 120 ° C. for 60 seconds, and the dry coating amount was 0.15 g / m. ² protective layers were formed to obtain planographic printing plate precursors of Examples 17 to 32.

<Coating liquid for protective layer (1)>
・ Inorganic layered compound dispersion (1) 1.5 g
-Polyvinyl alcohol (Nippon Synthetic Chemical Industry Co., Ltd. CKS50, sulfonic acid modification,
Saponification degree 99 mol% or more, polymerization degree 300) 6% by mass aqueous solution 0.55 g
・ Polyvinyl alcohol (PVA-405 manufactured by Kuraray Co., Ltd.)
Degree of saponification 81.5 mol%, degree of polymerization 500) 6% by weight aqueous solution 0.03 g
・ Nippon Emulsion Co., Ltd. surfactant (Emalex 710) 1% by weight aqueous solution 0.86g
・ Ion-exchanged water 6.0g

(Preparation of inorganic layered compound dispersion (1))
6.4 g of synthetic mica Somasif ME-100 (manufactured by Coop Chemical Co., Ltd.) was added to 193.6 g of ion-exchanged water, and dispersed using an homogenizer until the average particle size (laser scattering method) became 3 μm. The aspect ratio of the obtained dispersed particles was 100 or more.

[Comparative Examples 6-8]
In Example 17, lithographic printing plate precursors of Comparative Examples 6 to 8 were obtained in the same manner as in Example 17 except that the microcapsules were changed as shown in Table 5 below.

[Comparative Examples 9 to 10]
In Example 17, Comparative Example 9 to 10 were carried out in the same manner as in Example 17 except that 17 mg of triphenylphosphine was added during the preparation of the photosensitive solution (1) and the microcapsules were changed as shown in Table 5 below. A lithographic printing plate precursor was obtained.

[Evaluation of planographic printing plate precursor]

(1) On-machine developability The obtained lithographic printing plate precursor was subjected to an external drum rotation speed of 1000 rpm, a laser output of 70%, and a resolution of 2400 dpi on a Fujifilm Corporation Luxel PLASETTER T-6000III equipped with an infrared semiconductor laser. Exposed. The exposure image includes a thin line chart.
The obtained exposed original plate was attached to a plate cylinder of a printing machine LITHRONE 26 manufactured by Komori Corporation without developing. Equality-2 (manufactured by FUJIFILM Corporation) / tap water = 2/98 (volume ratio) dampening water and Values-G (N) black ink (manufactured by Dainippon Ink & Chemicals, Inc.) After dampening water and ink were supplied by the standard automatic printing start method of LITHRONE 26 and developed on the machine, 100 sheets were printed on Tokuhishi Art (76.5 kg) paper at a printing speed of 10,000 sheets per hour.
The number of print sheets required until the on-press development on the printing press of the unexposed portion of the image recording layer was completed and the ink was not transferred to the non-image portion was measured as on-press developability. The results are shown in Table 5.

(2) Fine line reproducibility Generally, in the case of a negative lithographic printing plate precursor, when the exposure amount is small, the degree of cure of the image recording layer (photosensitive layer) is low, and when the amount of exposure is large, the degree of cure is high. When the image recording layer has a too low degree of curing, the printing durability of the lithographic printing plate becomes low, and the reproducibility of small dots and fine lines becomes poor. On the other hand, when the degree of cure of the image recording layer is high, the printing durability is high, and the reproducibility of small dots and fine lines is good.
In this example, as shown below, the lithographic printing plate precursor obtained above was evaluated for printing durability and fine line reproducibility under the same exposure conditions described above, thereby improving the sensitivity of the lithographic printing plate precursor. It was used as an index. That is, it can be said that the sensitivity of the lithographic printing plate precursor is higher as the number of printed sheets in printing durability is higher and the fine line width in fine line reproducibility is thinner.
Specifically, after 100 sheets were printed as described above and it was confirmed that a printed matter having no ink stains in the non-image area was obtained, 500 sheets were continuously printed. A thin line chart (10, 12, 14, 16, 18, 20, 25, 30, 35, 40, 60, 80, 100, and 200 μm fine line exposed charts) of a total of 600 printed sheets with a 25X magnifier The fine line reproducibility was evaluated based on the fine line width that was observed and reproduced with ink without interruption. The level that can be reproduced up to 10 μm is indicated by ◯, and the level that can be reproduced up to 16 μm is indicated by Δ. The results are shown in Table 5.

(3) Dirtiness (storage stability)
A lithographic printing plate precursor that has been subjected to forced aging (temperature: 45 ° C., relative humidity: 75%, stored for 3 days) in an unexposed state is exposed and developed under the same conditions as in the on-machine developability evaluation, and printed 100 sheets. The non-image area contamination of the printed material was visually evaluated. The storage stability can be evaluated by comparing with the case where forced aging was not performed. The results are shown in Table 5.

(4) Printing durability After the above-described evaluation of on-press developability, the printing was further continued. As the number of printed sheets was increased, the image recording layer was gradually worn out, so that the ink density on the printed material decreased. Printing durability was evaluated using the number of printed copies when the value measured by the Gretag densitometer for the 50% halftone dot area ratio of the FM screen in the printed material was 5% lower than the measured value for the 100th printed sheet. . The results are shown in Table 5.

As is clear from Table 5, the lithographic printing plate precursors using the microcapsules of the present invention (Examples 17 to 32) were more resistant to stains than the lithographic printing plate precursors not containing the microcapsules of the present invention. There was an improvement in both printing durability.
Further, compared with the lithographic printing plate precursor using the conventional microcapsules not containing the phosphorus compound of the present invention (Comparative Examples 7 to 8), the lithographic printing plate precursor using the microcapsules of the present invention (Example 17). -32) is excellent in soiling properties after forced aging (after 45 days at 45 ° C. and 75% RH). Furthermore, even if a phosphorus compound is added later (Comparative Examples 9 to 10), the soiling property after forced aging (after 45 days at 45 ° C. and 75% RH) is inferior, and the effect cannot be obtained.

Claims (12)

  A microcapsule wherein the core material is a polymerizable unsaturated group-containing compound and a trivalent phosphorus compound, and the shell wall component containing the core material has a urea bond in the molecular structure.   The core material is a polymerizable unsaturated group-containing compound and a trivalent phosphorus compound, and the shell wall component containing this core material has a urea bond obtained by reaction with a polyisocyanate compound and water in the molecular structure. The microcapsule according to claim 1, wherein   The polyisocyanate compound is an adduct of a compound having two or more hydroxy groups in the molecule and a polyfunctional isocyanate compound having two or more isocyanate groups in the molecule. Item 3. A microcapsule according to Item 2.   The microcapsule according to claim 3, wherein the compound having two or more hydroxy groups in the molecule is a polyhydric phenol.   A method for producing a microcapsule, comprising emulsifying and dispersing an organic phase containing a trivalent phosphorus compound, a polymerizable unsaturated group-containing compound, and a polyisocyanate compound in an aqueous phase.   6. The polyisocyanate compound is an adduct of a compound having two or more hydroxy groups in a molecule and a polyfunctional isocyanate compound having two or more isocyanate groups in a molecule. Of manufacturing microcapsules.   The method for producing microcapsules according to claim 6, wherein the compound having two or more hydroxy groups in the molecule is a polyhydric phenol.   A (A) radically polymerizable compound, (B) a sensitizing dye, (C) a polymerization initiator, and (D) a microcapsule according to any one of claims 1 to 4 is contained on a hydrophilic support. A lithographic printing plate precursor comprising an image recording layer containing a polymerizable composition.   The lithographic printing plate precursor as claimed in claim 8, wherein the (B) sensitizing dye is an infrared absorber.   The lithographic printing plate precursor according to claim 8 or 9, comprising an image recording layer containing the polymerizable composition and a layer containing an inorganic stratiform compound in this order.   The lithographic printing plate precursor as claimed in any one of claims 8 to 10, wherein the unexposed portion of the image recording layer can be removed with at least one of dampening water and printing ink.   A lithographic printing plate precursor according to claim 11, wherein the lithographic printing plate precursor is image-exposed with an infrared laser, and then the unexposed portion of the image recording layer is removed with at least one of dampening water and printing ink.