JP2006264306A - Manufacturing method of lithographic printing original plate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method which enables to control deterioration in developability on a machine due to a transfer trouble of an image recording layer in a manufacturing process of a lithographic printing original plate using a resin minute particle and deterioration in developability on a machine due to deformation or breakage of the resin minute particle. <P>SOLUTION: The method for manufacturing the lithographic printing original plate is featured by carrying out contact of a manufacturing equipment and a base to a surface of the image recording layer under a state of lower than the glass transition temperature of the resin minute particle in a temperature of the image recording layer for the manufacturing method of the lithographic printing original plate having the image recording layer containing at least the resin minute particle on the base. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for producing a lithographic printing plate precursor using resin fine particles.

  Conventionally, the production of a lithographic printing plate has been performed by a system that exposes a printing plate precursor through a lith film, which is an intermediate material. However, with the rapid progress of digitization in the printing field in recent years, the printing plate preparation process is changing to a CTP system that directly outputs digital data input to a computer and edited to a printing plate precursor. Furthermore, with the aim of further streamlining processes, development-free lithographic printing plate precursors that can be printed as they are without being developed after exposure have been developed.

  One method of eliminating the processing step is to mount the exposed printing plate precursor on the plate cylinder of the printing press, and supply dampening water and ink while rotating the plate cylinder. There is a method called on-machine development that removes the image area. That is, after the printing plate precursor is exposed, it is mounted on a printing machine as it is, and the development process is completed in a normal printing process. A lithographic printing plate precursor suitable for on-press development has an image forming layer (heat-sensitive layer) that is soluble in fountain solution or ink solvent, and is developed on a printing press placed in a bright room. It is necessary to have a bright room handling property suitable for

  For example, Patent Document 1 describes a lithographic printing plate precursor in which a photosensitive layer in which fine particles of a thermoplastic hydrophobic polymer are dispersed in a hydrophilic binder polymer is provided on a hydrophilic support. In this publication, the lithographic printing plate precursor is subjected to infrared laser exposure, and the thermoplastic hydrophobic polymer fine particles in the image recording layer are coalesced by heat to form an image, and then the plate is mounted on the plate cylinder of a printing press. Further, it is described that an unexposed portion can be removed (on-press development) with a fountain solution and / or ink. This lithographic printing plate precursor also has suitability for handling a bright room because the photosensitive region is an infrared region.

  Patent Documents 2 to 6 also describe that a printing plate is prepared by on-press development after coalescence of thermoplastic fine particles by heat.

  Patent Document 7 discloses lithographic printing having an image recording layer containing at least one of thermoplastic polymer fine particles, polymer fine particles having a thermoreactive group, and microcapsules enclosing a compound having a thermoreactive group. It is described that the plate precursor has good on-press developability, high sensitivity, and high printing durability.

  Further, Patent Document 8 describes a good resistance to heat by using an on-press development type heat-sensitive lithographic printing plate precursor having a microcapsule containing a compound having a vinyloxy group, an image recording layer containing a hydrophilic resin and an acid precursor. It describes that printability can be obtained.

  Further, Patent Document 9 describes a good resistance to heat by using an on-press development type heat-sensitive lithographic printing plate precursor having a microcapsule enclosing a compound having an epoxy group, an image recording layer containing a hydrophilic resin and an acid precursor. It describes that printability can be obtained.

Further, Patent Document 10 discloses an on-press development type thermosensitive lithographic printing plate precursor having an image recording layer containing a microcapsule enclosing a compound having a radical polymerizable group, a hydrophilic resin and a thermosensitive polymerization initiator. It is described that good printing durability can be obtained.
Japanese Patent No. 2938397 JP-A-9-127683 JP-A-9-123387 JP-A-9-123388 JP-A-9-131850 WO99 / 10186 pamphlet JP 2001-293971 A JP 2002-29162 A JP 2002-46361 A JP 2002-137562 A

An on-press developable lithographic printing plate precursor having an image recording layer containing at least resin fine particles as described above is usually prepared by a known method by applying a coating solution in which an image recording layer component is dissolved or dispersed in an appropriate solvent. It can be obtained by coating and drying on top, but in the case of mass production, usually the support on the coil is continuously fed out, the image recording layer coating solution is applied, dried and then wound, or an appropriate size. A manufacturing method is adopted in which the cuts are aligned.
In the case of this mass production method, after the drying process, the surface of the image recording layer exceeds the glass transition temperature of the resin fine particles, and the surface of the image recording layer is brought into contact with a production facility such as a conveyance roller or is wound up to be a support. If the contact is made with the back surface of the film, a part or all of the image recording layer may be transferred to the contact object, or the resin fine particles may be deformed or destroyed. When the transfer occurs, the image recording layer and the back surface of the support are damaged, resulting in a defective product, and the yield is greatly reduced, and the productivity is lowered due to the roller contamination removing operation. When the resin fine particles are deformed or broken, the on-press developability of the lithographic printing plate precursor deteriorates, causing printing stains.
An object of the present invention is to provide a method for producing a lithographic printing plate precursor that suppresses the above-described transfer and does not deteriorate on-machine developability due to deformation or destruction of resin fine particles.

The present inventor has found that the above problem can be solved by the following means. That is, the present invention is as follows.
1. A method for producing a lithographic printing plate precursor having an image recording layer containing at least resin fine particles on a support, wherein the production equipment and the support are brought into contact with the surface of the image recording layer. A method for producing a lithographic printing plate precursor, which is performed at a temperature equal to or lower than a transition temperature.

2. 2. The method for producing a lithographic printing plate precursor as described in 1 above, wherein the resin fine particles are heat-reactive polymer fine particles.
3. 2. The method for producing a lithographic printing plate precursor as described in 1 above, wherein the resin fine particles are microcapsules or microgels containing a compound having a thermally reactive group.

4). The lithographic printing plate precursor as described in any one of 1 to 3 above, wherein the image recording layer contains an infrared absorber and a polymerization initiator in addition to resin fine particles, and is polymerized and cured by infrared laser irradiation. Manufacturing method.
5. 5. The method for producing a lithographic printing plate precursor as described in any one of 1 to 4 above, wherein the image recording layer can be removed with printing ink and / or fountain solution.

  ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method of the lithographic printing plate precursor which suppresses a transfer of an image recording layer, a deformation | transformation and destruction of resin fine particles, and does not raise | generate deterioration on-machine developability can be provided.

  The present invention relates to a method for producing an on-press developable lithographic printing plate precursor having an image recording layer containing at least resin fine particles on a support, particularly using a production apparatus. First, the manufacturing apparatus will be described with reference to the drawings.

〔Manufacturing equipment〕
FIG. 1 shows a coating, drying, and winding process in a planographic printing plate precursor manufacturing apparatus according to an embodiment of the present invention. On the most upstream side of the manufacturing apparatus, a feeding device (not shown) of an aluminum plate 59 as a support is installed, and this feeding device produces an aluminum plate 59 having a thickness of 0.1 to 0.6 mm on the production line. 1 is sent downstream at a traveling speed corresponding to the production speed of the planographic printing plate. Further, the production line 1 is provided with a plurality of conveyance rollers along the travel path of the aluminum plate 59, and the aluminum plate 59 is guided by the plurality of conveyance rollers and from the conveyance motor (not shown) via these conveyance rollers. Travels downstream at a predetermined speed. At this time, there are conveying rollers 51 to 57 that are in contact with the application surface such as the undercoat layer, the image recording layer, and the overcoat layer.

In the production line 1, first, the flatness required by correcting the shape of the aluminum plate 59 sent to the downstream side by the delivery device by a correction device (not shown) such as a roller leveler or a tension leveler in order to improve the flatness. Get. Next, after a roughening step, an anodizing treatment step, and if necessary, a hydrophilization treatment step, an undercoat layer coating solution is applied to the surface-treated surface of the aluminum plate 59 by the coating apparatus 2 and then passed through an undercoat layer drying furnace. An undercoat layer is formed.
As a method of applying the undercoat layer coating liquid to the aluminum plate 59, various known methods can be used. For example, bar coater coating, spin coating, spray coating, curtain coating, dip coating, air Examples include knife coating, blade coating, and roll coating.

In the production line 1, a hot air drying device is installed as a heating means on the downstream side of the coating device 2. The hot air drying apparatus is provided with a drying furnace 5 having an explosion-proof and heat-insulating structure and having an elongated casing shape along the traveling direction of the aluminum plate 59, and the traveling path of the aluminum plate 59 in the drying furnace 5. A plurality of support rolls are arranged along the line.
In the drying furnace 5, openings 16 and 17 are respectively formed on the upstream and downstream end faces along the traveling direction of the aluminum plate 59, and these openings 16 and 17 are respectively formed in the drying furnace 5 for the aluminum plate 59. The entrance and exit to Here, the aluminum plate 59 supplied into the drying furnace 5 from the opening 16 travels in the drying furnace 5 while being supported on the back surface side by the support roll, and comes out of the drying furnace 5 from the opening 17. A partition wall 22 is provided in the drying furnace 5 to partition the drying furnace 5 into a heating chamber 8 on the upstream side and a heating chamber 9 on the downstream side, and the partition wall 22 is provided between the heating chambers 8 and 9. Airflow movement is suppressed.
The upstream heating chamber 8 is provided with an air supply port 35 and an exhaust port 43, respectively, and a hot air generator (not shown) is connected to the intake port 35 via a duct or the like. A rectifying plate 27 is installed in the heating chamber 8 so as to face the air inlet 35. The rectifying plate 27 is formed with a plurality of slit-shaped air outlets. The rectifying plate 27 flows hot air supplied from the air inlet 35 into the heating chamber 8 along the surface of the aluminum plate 59. Rectify to such a high temperature airflow (hot air). At this time, 50 to 100 m ³ / min of hot gas is supplied to the air inlet 35 per 1 m of the width of the aluminum plate 59, and the temperature of the hot gas is controlled to 50 to 150 ° C. Thereby, in the heating chamber 8, about 80 mass% of the organic solvent contained in the undercoat layer at the time of application on the surface of the aluminum plate 59 evaporates, and the undercoat layer changes to a soft film.

An air supply port 36 and an exhaust port 44 are also provided in the heating chamber 9 on the downstream side, and a hot air generator (not shown) is connected to the air supply port 36 via a duct or the like. In the heating chamber 9, a rectifying plate 28 is installed between the air supply port 36 and the aluminum plate 59. The rectifying plate 28 is formed with a plurality of slit-shaped air outlets facing the surface of the aluminum plate 59, and the rectifying plate 28 is hot air supplied from the air supply port 36 into the heating chamber 9. Is rectified into a high-temperature airflow (hot air) that can be blown substantially vertically onto the surface of the aluminum plate 59.
At this time, a high temperature gas of 50 to 100 m ³ / min per 1 m width of the aluminum plate 12 is supplied to the intake port 36, and the temperature of this high temperature gas flow is controlled to 80 to 150 ° C. As a result, in the heating chamber 9, about 95% by mass or more of the organic solvent contained in the undercoat layer at the time of application on the surface of the aluminum plate 59 evaporates, and the undercoat layer that has been in the soft film state becomes dry to the touch.

  On the downstream side of the undercoat layer drying furnace, an image recording layer coating apparatus 3 for the aluminum plate 59 is installed, and an image recording layer coating solution is applied to the undercoat layer coating surface of the aluminum plate 59 to form an image recording layer. . As a method of applying the image recording layer coating solution to the aluminum plate 59, the same method as described in the case of the undercoat layer can be used.

A hot air drying device is installed as a heating means on the downstream side of the coating device 3. This hot-air drying apparatus is provided with a drying furnace 6 that has an explosion-proof and heat-insulating structure and has an elongated casing shape along the traveling direction of the aluminum plate 59, and the traveling path of the aluminum plate 59 in the drying furnace 6. A plurality of support rolls are arranged along the line.
In the drying furnace 6, openings 18 and 19 are respectively formed on the upstream and downstream end faces along the traveling direction of the aluminum plate 59, and these openings 18 and 19 are respectively formed in the drying furnace 6 for the aluminum plate 59. The entrance and exit to Here, the aluminum plate 59 supplied into the drying furnace 6 from the opening 18 travels in the drying furnace 6 while being supported on the back surface side by the support roll, and comes out of the drying furnace 6 from the opening 19. In the drying furnace 6, partition walls 23 and 24 are provided for partitioning the drying furnace 6 into an upstream heating chamber 10 and a downstream heating chamber 11 and 12, and these heating chambers 10, 11, and 12 are provided. Between them, the movement of the airflow is suppressed by the partition walls 23 and 24.

The heating chamber 10 on the upstream side is provided with an air supply port 37 and an exhaust port 45, and a hot air generator (not shown) is connected to the air supply port 37 via a duct or the like. A rectifying plate 29 is installed in the heating chamber 10 so as to face the air inlet 37. The rectifying plate 29 is formed with a plurality of slit-shaped outlets, and the rectifying plate 29 supplies hot air supplied from the air supply port 37 into the heating chamber 10 along the surface of the aluminum plate 59. Rectify into a flowing high-temperature airflow (hot air).
At this time, a high temperature gas of 50 to 100 m ³ / min per 1 m width of the aluminum plate 59 is supplied to the intake port 37, and the temperature of the high temperature gas is controlled to 50 to 150 ° C. As a result, in the heating chamber 10, about 80% by mass of the organic solvent contained in the image recording layer at the time of application on the surface of the aluminum plate 59 evaporates, and the applied layer changes to a soft film.

An air supply port 38 and an exhaust port 46 are also provided in the heating chamber 11 on the downstream side, and a hot air generator (not shown) is connected to the air supply port 38 via a duct or the like. In the heating chamber 11, a rectifying plate 30 is installed between the air supply port 38 and the aluminum plate 59. The rectifying plate 30 is formed with a plurality of slit-shaped air outlets facing the surface of the aluminum plate 59, and the rectifying plate 30 is hot air supplied from the air supply port 37 into the heating chamber 11. Is rectified into a high-temperature airflow (hot air) that can be blown substantially vertically onto the surface of the aluminum plate 59.
At this time, a high temperature gas of 50 to 100 m ³ / min per 1 m width of the aluminum plate 59 is supplied to the intake port 38, and the temperature of this high temperature gas flow is controlled to 80 to 150 ° C. Thereby, in the heating chamber 11, about 95 mass% or more of the organic solvent contained in the coating layer at the time of coating on the surface of the aluminum plate 59 evaporates, and the coating layer that has been in the soft film state becomes a dry-to-touch state.

The most downstream heating chamber 12 has substantially the same specifications as the heating chamber 11, but can be used as a cooling furnace depending on the situation. An air supply port 39 and an exhaust port 47 are respectively provided in the heating chamber 12, and a cold air and hot air generator (not shown) is connected to the air supply port 39 via a duct or the like. In the heating chamber 12, a rectifying plate 31 is installed between the air supply port 39 and the aluminum plate 59. The rectifying plate 31 is formed with a plurality of slit-shaped air outlets facing the surface of the aluminum plate 59, and the rectifying plate 31 is hot air supplied from the air supply port 39 into the heating chamber 12. Is rectified into a low-temperature or high-temperature airflow (cold air or hot air) that can be blown substantially vertically onto the surface of the aluminum plate 59.
At this time, 50 to 100 m ³ / min of hot gas per 1 m width of the aluminum plate 59 is supplied to the air inlet 39, and the temperature of this hot gas flow is controlled to 25 to 150 ° C. As a result, the heating chamber 12 is cooled so that the temperature of the surface of the image recording layer on the aluminum plate 59 is 100 ° C. or less, or about 95% by mass or more of the organic solvent contained in the image recording layer at the time of application. Evaporates, and the image recording layer becomes dry to the touch.

The aluminum plate that has exited the opening 19 comes into contact with the conveying roller 53 on the image recording layer application surface. In the present invention, by making the temperature of the image recording layer not more than the glass transition temperature of the resin fine particles at the time of contact, the transfer of the image recording layer is suppressed, and a lithographic printing plate precursor having good on-press developability can be produced. Got the way.
As a method for controlling the temperature of the image recording layer after drying, the amount of heat applied when drying the coating liquid provided on the support, the amount of coating liquid applied on the support, and the conveyance speed of the support web are determined. Examples of the method include optimizing and cooling with a cool air after drying. Among these, the method of cooling by applying cold air after drying is most preferably used in that cost and stable performance can be obtained. Specifically, it is a method in which a sufficient amount of heat is given in the heating chambers 10 and 11 and the heating chamber 12 is used as a cooling furnace. The method of suppressing the amount of heat applied at the time of drying does not stabilize the amount of coating solvent remaining in the image recording layer, and may adversely affect performance such as stability over time. A method of increasing the amount of coating solution or reducing the conveyance speed so that the temperature does not rise is disadvantageous in terms of manufacturing cost.

In the production line 1, PVA (polyvinyl alcohol), swellable mica and the like are further applied on the image recording layer on the downstream side of the drying furnace 6 as necessary for the purpose of blocking oxygen and the like to form an overcoat layer. As a method for applying the overcoat layer coating solution to the aluminum plate 59, a method similar to that described in the case of the undercoat layer can be used.
A hot air drying device is installed as a heating means on the downstream side of the coating device 4. The hot air drying apparatus has an explosion-proof and heat-insulating structure, and is provided with a drying furnace 7 having an elongated casing shape along the traveling direction of the aluminum plate 59. The traveling path of the aluminum plate 59 is provided in the drying furnace 7. A plurality of support rolls are arranged along the line.
In the drying furnace 7, openings 20 and 21 are respectively formed on the upstream and downstream end faces along the traveling direction of the aluminum plate 59, and these openings 20 and 21 are respectively formed in the drying furnace 7 for the aluminum plate 59. The entrance and exit to Here, the aluminum plate 59 supplied into the drying furnace 7 from the opening 20 travels inside the drying furnace 7 while being supported on the back side by the support rolls, and comes out of the drying furnace 7 from the opening 21. In the drying furnace 7, partition walls 25 and 26 are provided to partition the drying furnace 7 into an upstream heating chamber 13 and downstream heating chambers 14 and 15, and these heating chambers 13, 14, 15 are provided. Between them, the movement of the airflow is suppressed by the partition walls 25 and 26.

The heating chamber 13 on the upstream side is provided with an air supply port 40 and an exhaust port 48, and a hot air generator (not shown) is connected to the air supply port 40 via a duct or the like. A rectifying plate 32 is installed in the heating chamber 13 so as to face the air inlet 40. The rectifying plate 32 is formed with a plurality of slit-shaped air outlets. The rectifying plate 32 allows high-temperature air supplied from the air supply port 40 into the heating chamber 13 along the surface of the aluminum plate 59. Rectify into a flowing high-temperature airflow (hot air).
At this time, a high temperature gas of 50 to 100 m ³ / min per 1 m width of the aluminum plate 59 is supplied to the intake port 40, and the temperature of the high temperature gas is controlled to 50 to 150 ° C. Thereby, in the heating chamber 13, about 80 mass% of the organic solvent contained in the overcoat layer at the time of application on the surface of the aluminum plate 59 evaporates, and the application layer changes to a soft film.
An air supply port 41 and an exhaust port 49 are also provided in the heating chamber 14 on the downstream side, and a hot air generator (not shown) is connected to the air supply port 41 via a duct or the like. A rectifying plate 33 is installed in the heating chamber 14 between the air supply port 41 and the aluminum plate 59. The rectifying plate 33 is formed with a plurality of slit-shaped air outlets facing the surface of the aluminum plate 59, and the rectifying plate 33 is hot air supplied from the air supply port 41 into the heating chamber 14. Is rectified into a high-temperature airflow (hot air) that can be blown substantially vertically onto the surface of the aluminum plate 59.
At this time, a high temperature gas of 50 to 100 m ³ / min per 1 m width of the aluminum plate 59 is supplied to the intake port 41, and the temperature of this high temperature gas flow is controlled to 80 to 150 ° C. Thereby, in the heating chamber 14, about 95 mass% or more of the organic solvent contained in the coating layer at the time of coating on the surface of the aluminum plate 59 evaporates, and the coating layer that has been in the soft film state becomes a dry-to-touch state.

The most downstream heating chamber 15 has substantially the same specifications as the heating chamber 14, but can be used as a cooling furnace depending on the situation. The heating chamber 15 is provided with an air supply port 42 and an exhaust port 50, respectively, and cold air and hot air generators (not shown) are connected to the air supply port 42 via a duct or the like. In the heating chamber 15, a rectifying plate 34 is installed between the air supply port 42 and the aluminum plate 59. The rectifying plate 34 is formed with a plurality of slit-shaped air outlets facing the surface of the aluminum plate 59, and the rectifying plate 34 is hot air supplied from the air inlet 42 into the heating chamber 15. Is rectified into a low-temperature or high-temperature airflow (cold air or hot air) that can be blown substantially vertically onto the surface of the aluminum plate 59.
At this time, low-temperature or high-temperature gas of 50 to 100 m ³ / min per 1 m width of the aluminum plate 59 is supplied to the air inlet 42, and the temperature of this high-temperature gas flow is controlled to 25 to 150 ° C. Thereby, in the heating chamber 15, it is cooled so that the temperature of the surface of the overcoat layer on the aluminum plate 59 is 100 ° C. or less, or about 95% by mass or more of the organic solvent contained in the overcoat layer at the time of application. Evaporates and the overcoat layer becomes dry to the touch.

The web manufactured as described above is wound into a roll by the web winder 58 to form a web roll. In the case of a lithographic printing plate precursor not provided with an overcoat layer, after exiting the opening 19 and passing through the coating and drying zone of the overcoat layer as it is, in addition to the method of winding in a roll shape with the web winder 58 After exiting the opening 19, it can be wound into a roll by the web winder 58 directly through the transport roll 57. In this case, the surface of the image recording layer comes into contact with the back surface of the support immediately after drying. Even at the time of this contact, the temperature of the image recording layer of the present invention is set to be equal to or lower than the glass transition temperature of the resin fine particles. Transfer of the recording layer and deformation and destruction of the resin fine particles can be suppressed.
This web roll is supplied to a processing line, and is attached with a protective interleaving paper, cut into a product size, and the like to produce a lithographic printing plate precursor as a product.

(Image recording layer)
The image recording layer of the present invention contains resin fine particles. The image recording layer of the present invention preferably contains an infrared absorber and a polymerization initiator and is of a type that is polymerized and cured by infrared laser irradiation. The image recording layer of the present invention is preferably removable with printing ink and / or fountain solution.
Hereinafter, the elements of such an image recording layer will be described.

<Resin fine particles>
The resin fine particles used in the present invention are at least one fine particle selected from thermoplastic polymer fine particles, heat-reactive polymer fine particles, and microcapsules or microgels containing a compound having a heat-reactive group.

  Examples of the thermoplastic polymer fine particles used in the present invention include Research Disclosure No. 1 of January 1992. 33303, JP-A-9-123387, JP-A-9-131850, JP-A-9-171249, JP-A-9-171250, European Patent No. 931647, and the like are suitable. Can be cited as Specific examples of the polymer constituting the polymer fine particle include homopolymers of monomers such as ethylene, styrene, vinyl chloride, methyl acrylate, ethyl acrylate, methyl methacrylate, ethyl methacrylate, vinylidene chloride, acrylonitrile, vinyl carbazole, or the like. Mention may be made of copolymers or mixtures thereof. Among them, more preferred are polystyrene and polymethyl methacrylate.

  The average particle size of the thermoplastic polymer fine particles used in the present invention is preferably 0.01 to 2.0 μm. As a method for synthesizing such thermoplastic polymer fine particles, in addition to emulsion polymerization and suspension polymerization, these compounds are dissolved in a water-insoluble organic solvent, and this is mixed and emulsified with an aqueous solution containing a dispersant. Further, there is a method (solution dispersion method) in which heat is further applied to solidify into fine particles while the organic solvent is being blown away.

  Examples of the heat-reactive polymer fine particles used in the present invention include thermosetting polymer fine particles and polymer fine particles having a heat-reactive group.

  Examples of the thermosetting polymer include a resin having a phenol skeleton, a urea resin (for example, a urea derivative such as urea or methoxymethylated urea resinized with an aldehyde such as formaldehyde), a melamine resin (for example, melamine or Examples thereof include those obtained by converting the derivatives into resins with aldehydes such as formaldehyde, alkyd resins, unsaturated polyester resins, polyurethane resins, and epoxy resins. Among these, resins having a phenol skeleton, melamine resins, urea resins and epoxy resins are particularly preferable.

  Suitable resins having a phenol skeleton include, for example, phenol resins obtained by resinizing phenol, cresol, etc. with aldehydes such as formaldehyde, hydroxystyrene resins, N- (p-hydroxyphenyl) methacrylamide, and p-hydroxyphenyl methacrylate. Examples thereof include a polymer or copolymer of methacrylamide or acrylamide or methacrylate or acrylate having a phenol skeleton.

  The average particle diameter of the thermosetting polymer fine particles used in the present invention is preferably 0.01 to 2.0 μm. Such thermosetting polymer fine particles can be easily obtained by a solution dispersion method, but may be formed into fine particles when the thermosetting polymer is synthesized. However, it is not restricted to these methods.

  The thermally reactive group of the polymer fine particle having a thermally reactive group used in the present invention may be any functional group that performs a reaction as long as a chemical bond is formed, but is an ethylenically unsaturated group that performs a radical polymerization reaction. Group (for example, acryloyl group, methacryloyl group, vinyl group, allyl group, etc.), cationically polymerizable group (for example, vinyl group, vinyloxy group, etc.), isocyanate group that performs addition reaction or its block, epoxy group, vinyloxy group And a functional group having an active hydrogen atom as a reaction partner (for example, an amino group, a hydroxyl group, a carboxyl group, etc.), a carboxyl group for performing a condensation reaction, a hydroxyl group or an amino group as a reaction partner, a ring-opening addition reaction The acid anhydride to be used and the amino group or hydroxyl group as the reaction partner may be mentioned as suitable ones. Kill.

  The introduction of these functional groups into the polymer fine particles may be performed at the time of polymerization, or may be performed using a polymer reaction after the polymerization.

  When introduced at the time of polymerization, it is preferable to carry out emulsion polymerization or suspension polymerization of the monomer having the above functional group. Specific examples of the monomer having the above functional group include allyl methacrylate, allyl acrylate, vinyl methacrylate, vinyl acrylate, 2- (vinyloxy) ethyl methacrylate, p-vinyloxystyrene, p- {2- (vinyloxy) ethyl} styrene, Block isocyanate with glycidyl methacrylate, glycidyl acrylate, 2-isocyanatoethyl methacrylate or alcohol thereof, block isocyanate with 2-isocyanate ethyl acrylate or alcohol thereof, 2-aminoethyl methacrylate, 2-aminoethyl acrylate, 2- Hydroxyethyl methacrylate, 2-hydroxyethyl acrylate, acrylic acid, methacrylic acid, maleic anhydride, bifunctional acrylate, 2 officers Methacrylate, and the like, but not limited thereto.

  In the present invention, a copolymer of these monomers and a monomer that is copolymerizable with these monomers and does not have a thermally reactive group can also be used. Examples of the copolymer monomer having no heat-reactive group include styrene, alkyl acrylate, alkyl methacrylate, acrylonitrile, vinyl acetate, and the like. It is not limited to.

  Examples of the polymer reaction used when the introduction of the thermally reactive group is carried out after the polymerization include the polymer reaction described in International Publication No. 96/34316 pamphlet.

  Among the polymer fine particles having a thermoreactive group, those in which the polymer fine particles are coalesced by heat are preferable, and those having a hydrophilic surface and dispersed in water are particularly preferable. The contact angle (water droplets) of the film prepared by applying only polymer fine particles and drying at a temperature lower than the solidification temperature is higher than the contact angle (water droplets) of the film prepared by drying at a temperature higher than the solidification temperature. It is preferable to lower. In order to make the surface of the polymer fine particles hydrophilic in this way, a hydrophilic polymer or oligomer such as polyvinyl alcohol or polyethylene glycol or a hydrophilic low molecular weight compound may be adsorbed on the surface of the polymer fine particles. However, the surface hydrophilization method is not limited to this.

  The solidification temperature of the polymer fine particles having these thermoreactive groups is preferably 70 ° C. or higher, but more preferably 100 ° C. or higher in view of the stability over time. The average particle size of the polymer fine particles is preferably 0.01 to 2.0 μm, more preferably 0.05 to 2.0 μm, and most preferably 0.1 to 1.0 μm. Within this range, good resolution and stability over time can be obtained.

  The microcapsule or microgel used in the present invention includes a compound having a thermoreactive group. As this heat-reactive group, the same heat-reactive group as that used for the polymer fine particles having the heat-reactive group can be mentioned as a preferable one. Hereinafter, the compound having a thermally reactive group will be described in more detail.

Preferred examples of the compound having a radically polymerizable unsaturated group include a compound having at least one, preferably two or more, ethylenically unsaturated bonds such as acryloyl group, methacryloyl group, vinyl group and allyl group. . Such a group of compounds is widely known as a monomer or a crosslinking agent for the polymerizable composition in the industrial field, and these can be used in the present invention without any particular limitation. The chemical form is a monomer, a prepolymer, that is, a dimer, a trimer, an oligomer, a polymer or a copolymer, or a mixture thereof.

  Specific examples include compounds described in JP-A-2001-277740 as compounds having a polymerizable unsaturated group. Representative compound examples include bis (acryloxyethyl) isocyanurate, tri (acryloxyethyl) isocyanurate, trimethylolpropane di (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol di (meth) acrylate , Pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol di (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, trimethylolpropane diacrylate and Examples include adducts with xylylene diisocyanate. However, it is not limited to these.

  An example of a polymer or copolymer having an ethylenically polymerizable unsaturated group is a copolymer of allyl methacrylate. For example, allyl methacrylate / methacrylic acid copolymer, allyl methacrylate / ethyl methacrylate copolymer, allyl methacrylate / butyl methacrylate copolymer and the like can be mentioned.

  Examples of the compound having a vinyloxy group suitable for the present invention include compounds described in JP-A No. 2002-29162. Specific examples include tetramethylene glycol divinyl ether, trimethylolpropane trivinyl ether, tetraethylene glycol divinyl ether, pentaerythritol divinyl ether, pentaerythritol trivinyl ether, pentaerythritol tetravinyl ether, 1,4-bis {2- (vinyloxy) ethyloxy} Benzene, 1,2-bis {2- (vinyloxy) ethyloxy} benzene, 1,3-bis {2- (vinyloxy) ethyloxy} benzene, 1,3,5-tris {2- (vinyloxy) ethyloxy} benzene, 4 , 4′-bis {2- (vinyloxy) ethyloxy} biphenyl, 4,4′-bis {2- (vinyloxy) ethyloxy} diphenyl ether, 4,4′-bis {2- (vinyloxy) ester Ruoxy} diphenylmethane, 1,4-bis {2- (vinyloxy) ethyloxy} naphthalene, 2,5-bis {2- (vinyloxy) ethyloxy} furan, 2,5-bis {2- (vinyloxy) ethyloxy} thiophene, , 5-bis {2- (vinyloxy) ethyloxy} imidazole, 2,2-bis [4- {2- (vinyloxy) ethyloxy} phenyl] propane {bis (vinyloxyethyl) ether of bisphenol A}, 2,2- Examples include, but are not limited to, bis {4- (vinyloxymethyloxy) phenyl} propane, 2,2-bis {4- (vinyloxy) phenyl} propane, and the like.

  As the compound having an epoxy group suitable for the present invention, a compound having two or more epoxy groups is preferable, and a glycidyl ether compound obtained by reaction of a polyhydric alcohol or a polyhydric phenol with epichlorohydrin or a prepolymer thereof. Furthermore, a polymer or copolymer of glycidyl acrylate or glycidyl methacrylate can be used.

  Specific examples include propylene glycol diglycidyl ether, tripropylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, neopentyl glycol diglycidyl ether, trimethylolpropane triglycidyl ether, diglycidyl ether of hydrogenated bisphenol A, hydroquinone diglycidyl. Ether, resorcinol diglycidyl ether, diglycidyl ether or epichlorohydrin polyadduct of bisphenol A, diglycidyl ether or epichlorohydrin polyadduct of bisphenol F, diglycidyl ether or epichlorohydride of halogenated bisphenol A Phosphorus polyadduct, diglycidyl ether of biphenyl type bisphenol or epichlorohydrin polyadduct, novolak tree Etc. glycidyl ethers, furthermore, methyl methacrylate / glycidyl methacrylate copolymer, methacrylic acid ethyl / glycidyl methacrylate copolymer, and the like.

  Commercially available products of the above compounds include, for example, Epicoat 1001 (molecular weight: about 900, epoxy equivalent: 450 to 500), Epicoat 1002 (molecular weight: about 1600, epoxy equivalent: 600 to 700), Epicoat 1004 (about) manufactured by Japan Epoxy Resin Co., Ltd. 1060, epoxy equivalent 875-975), Epicoat 1007 (molecular weight about 2900, epoxy equivalent 2000), Epicoat 1009 (molecular weight about 3750, epoxy equivalent 3000), Epicoat 1010 (molecular weight about 5500, epoxy equivalent 4000), Epicoat 1100L (epoxy equivalent) 4000), Epicoat YX31575 (epoxy equivalent 1200), Sumitomo Chemical Co., Ltd. Sumiepoxy ESCN-195XHN, ESCN-195XL, ESCN-195XF, and the like.

  Suitable isocyanate compounds for the present invention include tolylene diisocyanate, diphenylmethane diisocyanate, polymethylene polyphenyl polyisocyanate, xylylene diisocyanate, naphthalene diisocyanate, cyclohexanephenylene diisocyanate, isophorone diisocyanate, Examples include hexamethylene diisocyanate, cyclohexyl diisocyanate, and compounds obtained by blocking these with alcohol or amine.

  Suitable amine compounds for the present invention include ethylenediamine, diethylenetriamine, triethylenetetramine, hexamethylenediamine, propylenediamine, polyethyleneimine and the like.

  Examples of the compound having a hydroxyl group suitable for the present invention include a compound having a terminal methylol group, a polyhydric alcohol such as pentaerythritol, and bisphenol / polyphenols.

  Examples of the compound having a carboxyl group suitable for the present invention include aromatic polyvalent carboxylic acids such as pyromellitic acid, trimellitic acid and phthalic acid, and aliphatic polyvalent carboxylic acids such as adipic acid.

  Examples of the acid anhydride suitable for the present invention include pyromellitic acid anhydride and benzophenone tetracarboxylic acid anhydride.

  As a method for microencapsulating or microgelling the compound having the above-mentioned heat-reactive group, a known method can be applied.

For example, as a method for producing microcapsules, US Pat. No. 2,800,547, US Pat. No. 2,800,498, a method using coacervation, US Pat. No. 3,287,154, Japanese Patent Publication No. 38-19574, A method based on an interfacial polymerization method found in US Pat. No. 42-446, a method based on precipitation of a polymer found in US Pat. Nos. 3,418,250 and 3,660,304, an isocyanate found in US Pat. No. 3,796,669. Method using polyol wall material, method using isocyanate wall material found in US Pat. No. 3,914,511, urea found in US Pat. Nos. 4,001,140, 4,087,376 and 4,089,802 -Formaldehyde or urea formaldehyde -A method using a resorcinol-based wall forming material, a method using a wall material such as melamine-formaldehyde resin, hydroxycellulose, etc. found in US Pat. No. 4,025,445, Japanese Patent Publication Nos. 36-9163 and 51-9079. In-situ method by monomer polymerization, British Patent No. 930422, US Pat. No. 3,111,407 Spray drying method, British Patent No. 952807, US Pat. No. 9,670,741 Although there is a cooling method, it is not limited to these.

  A preferable microcapsule wall used in the present invention has a three-dimensional cross-linking and has a property of swelling with a solvent. From such a viewpoint, the wall material of the microcapsule is preferably polyurea, polyurethane, polyester, polycarbonate, polyamide, and a mixture thereof, and particularly preferably polyurea and polyurethane. Further, a compound having a crosslinkable functional group such as an ethylenically unsaturated bond capable of introducing a binder polymer may be introduced into the microcapsule wall.

On the other hand, as a method for preparing the microgel, granulation by interfacial polymerization described in JP-B-38-19574 and JP-A-42-446, non-patent document as described in JP-A-5-61214, and the like. Granulation by aqueous dispersion polymerization can be used. However, it is not limited to these methods.
As the method using the interfacial polymerization, the known microcapsule production method described above can be applied.

  Preferred microgels used in the present invention are those granulated by interfacial polymerization and having three-dimensional crosslinking. From such a viewpoint, the material to be used is preferably polyurea, polyurethane, polyester, polycarbonate, polyamide, and a mixture thereof, and polyurea and polyurethane are particularly preferable.

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

  Such microcapsules or microgels may or may not be combined with each other by heat. In short, among microcapsule inclusions or microgel inclusions, those that have exuded outside the capsule surface or microgel surface or microcapsule or microgel at the time of application, or those that have infiltrated the microcapsule wall or microgel wall are chemically treated by heat. It only has to react. You may react with the added hydrophilic resin or the added low molecular weight compound. Alternatively, two or more types of microcapsules or microgels may be reacted with each other by providing functional groups that react with each other with different functional groups. Therefore, it is preferable for image formation that the microcapsules or the microgels are fused and merged by heat, but it is not essential.

  Among the resin fine particles used in the present invention, a microcapsule or a microgel that includes a compound having a thermoreactive polymer particle and a thermoreactive group is more preferable, and a polymer particle having a thermoreactive group and a polymerizable compound are included. More preferred are microcapsules or microgels.

  In the case of thermoplastic polymer fine particles, the amount of the polymer fine particles and microcapsules or microgel added to the image recording layer is preferably 50% by mass or more, more preferably 70% by mass or more, based on the solid content of the image recording layer. In the case of heat-reactive polymer fine particles, the image recording layer solid content is preferably 20% by mass or more, more preferably 25 to 85% by mass. Further, in the case of microcapsules or microgels, the solid content of the image recording layer is preferably 15% by mass or more, and more preferably 20 to 75% by mass. In any of these ranges, a good image can be formed and a good printing durability can be obtained.

  When the microcapsule or microgel is contained in the image recording layer of the present invention, a solvent capable of dissolving the inclusion and swelling the wall material can be added to the microcapsule or microgel dispersion medium. By such a solvent, the diffusion of the encapsulated thermoreactive group compound outside the microcapsule or microgel is promoted. Such a solvent can be easily selected from many commercially available solvents, although it depends on the microcapsule or microgel dispersion medium, the material of the microcapsule or microgel wall, the wall thickness and the inclusion. For example, in the case of water-dispersible microcapsules or microgels composed of crosslinked polyurea and polyurethane walls, alcohols, ethers, acetals, esters, ketones, polyhydric alcohols, amides, amines, fatty acids and the like are preferable.

  Specific compounds include methanol, ethanol, tertiary butanol, n-propanol, tetrahydrofuran, methyl lactate, ethyl lactate, methyl ethyl ketone, propylene glycol monomethyl ether, ethylene glycol diethyl ether, ethylene glycol monomethyl ether, γ-butyl lactone, N, There are N-dimethylformamide, N, N-dimethylacetamide, and the like, but not limited thereto. Two or more of these solvents may be used. A solvent that does not dissolve in the microcapsule or microgel dispersion but dissolves when the solvent is mixed can also be used.

  The amount of the solvent added is determined by the combination of materials, but usually 5 to 95% by mass of the coating solution is effective, and a preferable range is 10 to 90% by mass, and a more preferable range is 15 to 85%. % By mass.

<Infrared absorber>
In the image recording layer of the present invention, an infrared absorber is preferably used in order to increase sensitivity. The infrared absorber has a function of converting absorbed infrared rays into heat. The infrared absorber used in the present invention is a dye or pigment having an absorption maximum at a wavelength of 760 to 1200 nm.

  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, etc. Is mentioned.

  Examples of preferable dyes include cyanine dyes described in JP-A-58-125246, JP-A-59-84356, JP-A-60-78787, JP-A-58-173696, Methine dyes described in JP-A Nos. 58-181690 and 58-194595, JP-A-58-112793, JP-A-58-224793, JP-A-59-48187, JP-A Naphthoquinone dyes described in JP-A-59-73996, JP-A-60-52940, JP-A-60-63744, etc., squarylium dyes described in JP-A-58-112792, etc., British Patent No. And cyanine dyes described in the specification of 434,875.

In addition, a near infrared absorption sensitizer described in US Pat. No. 5,156,938 is also preferably used, and a substituted arylbenzo (thio) described in US Pat. No. 3,881,924 is also suitable. ) Pyrylium salt, trimethine thiapyrylium salt described in JP-A-57-142645 (US Pat. No. 4,327,169), JP-A-58-181051, 58-220143, 59- No. 41363, 59-84248, 59-84249, 59-146063, 59-146061, pyranyl compounds described in JP-A-59-216146, cyanine dyes described in US It is disclosed in the pentamethine thiopyrylium salt described in Japanese Patent No. 4,283,475, and Japanese Patent Publication Nos. 5-13514 and 5-19702. Pyrylium compounds are also preferably used. Another example of a preferable dye is a near-infrared absorbing dye described in US Pat. No. 4,756,993 as formulas (I) and (II).
Other preferable examples of the infrared absorbent of the present invention include specific indolenine cyanine dyes described in JP-A-2002-278057.

  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 one particularly preferred example is a cyanine dye represented by the following general formula (I).

In the general formula (I), X ¹ represents a hydrogen atom, a halogen atom, -NPh _2, X ² -L ¹ or a group shown below. Here, X ² represents an oxygen atom, a nitrogen 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 1 to 1 carbon atom containing a hetero atom. 12 hydrocarbon groups are shown. In addition, a hetero atom here shows N, S, O, a halogen atom, and Se.

Xa ^- the 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 recording layer coating solution, R ¹ and R ² are preferably hydrocarbon groups having 2 or more carbon atoms, and R ¹ and R ² are bonded to each other to form a 5-membered ring or It is particularly preferable that a 6-membered ring is formed.

Ar ¹ and Ar ² may be the same or different and each represents an aromatic hydrocarbon group which may have a substituent. Preferred aromatic hydrocarbon 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, carboxyl 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 formula (I) has an anionic substituent in its structure and neutralization of charge is not necessary. Preferred Za ⁻ is a halogen ion, a perchlorate ion, a tetrafluoroborate ion, a hexafluorophosphate ion, and a sulfonate ion, particularly preferably a perchlorate ion, a hexagonal salt, in view of the storage stability of the recording layer coating solution. Fluorophosphate ion and aryl sulfonate ion.

Specific examples of the cyanine dye represented by formula (I) that can be suitably used in the present invention include those described in paragraph numbers [0017] to [0019] of JP-A No. 2001-133969. be able to.
Further, other particularly preferable examples include specific indolenine cyanine dyes described in JP-A-2002-278057 described above.

  Examples of the pigment used in the present invention include commercially available pigments and color index (CI) manual, “Latest Pigment Handbook” (edited by Japan Pigment Technology Association, published in 1977), “Latest Pigment Application Technology” (CMC Publishing, 1986), “Printing Ink Technology”, CMC Publishing, 1984) can be used.

  Examples of the pigment include black pigments, yellow pigments, orange pigments, brown pigments, red pigments, purple pigments, blue pigments, green pigments, fluorescent pigments, metal powder pigments, and other polymer-bonded dyes. Specifically, insoluble azo pigments, azo lake pigments, condensed azo pigments, chelate azo pigments, phthalocyanine pigments, anthraquinone pigments, perylene and perinone pigments, thioindigo pigments, quinacridone pigments, dioxazine pigments, isoindolinone pigments , Quinophthalone pigments, dyed lake pigments, azine pigments, nitroso pigments, nitro pigments, natural pigments, fluorescent pigments, inorganic pigments, carbon black, and the like. Among these pigments, carbon black is preferable.

  These pigments may be used without surface treatment, or may be used after surface treatment. The surface treatment method includes a method of surface coating with a resin or wax, a method of attaching a surfactant, a method of bonding a reactive substance (eg, silane coupling agent, epoxy compound, polyisocyanate, etc.) to the pigment surface, etc. Can be considered. The above-mentioned surface treatment methods are described in “Characteristics and Applications of Metal Soap” (Yokoshobo), “Printing Ink Technology” (CMC Publishing, 1984) and “Latest Pigment Application Technology” (CMC Publishing, 1986). Yes.

  The particle diameter of the pigment is preferably in the range of 0.01 to 10 μm, more preferably in the range of 0.05 to 1 μm, and particularly preferably in the range of 0.1 to 1 μm. Within this range, good stability of the pigment dispersion in the image recording layer coating solution and good uniformity of the image recording layer can be obtained.

As a method for dispersing the pigment, a known dispersion technique used in ink production, toner production, or the like can be used. Examples of the disperser include an ultrasonic disperser, a sand mill, an attritor, a pearl mill, a super mill, a ball mill, an impeller, a disperser, a KD mill, a colloid mill, a dynatron, a three-roll mill, and a pressure kneader. Details are described in "Latest Pigment Applied Technology" (CMC Publishing, 1986).

These infrared absorbers may be added to the same layer as other components, or another layer may be provided and added thereto. Further, it can be added by being encapsulated in microcapsules or microgels.
As the addition amount, when a negative lithographic printing plate precursor is prepared, the absorbance at the maximum absorption wavelength in the wavelength range of 760 nm to 1200 nm of the image recording layer is in the range of 0.3 to 1.2 by the reflection measurement method. It is preferable to add such that it is in a range of 0.4 to 1.1. Within this range, a uniform polymerization reaction proceeds in the depth direction of the image recording layer, and good film strength of the image area and adhesion to the support can be obtained.

  The absorbance of the image recording layer can be adjusted by the amount of infrared absorber added to the image recording layer and the thickness of the image recording layer. Absorbance can be measured by a conventional method. As a measuring method, for example, on a reflective support such as aluminum, an image recording layer having a thickness appropriately determined in a range in which the coating amount after drying is necessary as a lithographic printing plate is formed, and the reflection density is set to the optical density. And a method of measuring with a spectrophotometer by a reflection method using an integrating sphere.

<Polymerization initiator>
In the present invention, a polymerization initiator can be used to initiate and accelerate the polymerization reaction of a thermally reactive group, particularly a polymerizable group. A polymerization initiator is a compound that initiates and accelerates the polymerization of a compound having a polymerizable unsaturated group by generating radicals by energy of light, heat, or both. Examples of the polymerization initiator that can be used in the present invention include known thermal polymerization initiators, compounds having a bond with small bond dissociation energy, and photopolymerization initiators.

  Examples of the polymerization initiator as described above include organic halogen compounds, carbonyl compounds, organic peroxides, azo polymerization initiators, azide compounds, metallocene compounds, hexaarylbiimidazole compounds, organic boron compounds, disulfone compounds, and oximes. Examples thereof include ester compounds and onium salt compounds.

  Specific examples of the organic halogen compound include Wakabayashi et al., “Bull Chem. Soc Japan” 42, 2924 (1969), US Pat. No. 3,905,815, Japanese Patent Publication No. 46-4605, JP 48-36281, JP 53-133428, JP 55-3070, JP 60-239736, JP 61-169835, JP 61-169837, JP 62- 58241, JP-A 62-212401, JP-A 63-70243, JP-A 63-298339, P. Examples include compounds described in Hutt, “Journal of Heterocyclic Chemistry” 1 (No. 3), (1970). Of these, oxazole compounds and S-triazine compounds substituted with a trihalomethyl group are preferred.

More preferably, an s-triazine derivative having at least one mono, di, or trihalogen-substituted methyl group bonded to the s-triazine ring, specifically, for example, 2,4,6-tris (monochloromethyl)- s-triazine, 2,4,6-tris (dichloromethyl) -s-triazine, 2,4,6-tris (trichloromethyl) -s-triazine, 2-methyl-4,6-bis (trichloromethyl)- s-triazine, 2-n-propyl-4,6-bis (trichloromethyl) -s-triazine, 2- (α, α, β-trichloroethyl) -4,6-bis (trichloromethyl) -s-triazine 2-phenyl-4,6-bis (trichloromethyl) -s-triazine, 2- (p-methoxyphenyl) -4,6-bis (trichloromethyl) -s-triazine, -(3,4-epoxyphenyl) -4,6-bis (trichloromethyl) -s-triazine, 2- (p-chlorophenyl) -4,6-bis (trichloromethyl) -s-triazine, 2- [1 -(P-methoxyphenyl) -2,4-butadienyl] -4,6-bis (trichloromethyl) -s-triazine, 2-styryl-4,6-bis (trichloromethyl) -s-triazine, 2- ( p-methoxystyryl) -4,6-bis (trichloromethyl) -s-triazine, 2- (pi-propyloxystyryl) -4,6-bis (trichloromethyl) -s-triazine, 2- (p -Tolyl) -4,6-bis (trichloromethyl) -s-triazine, 2- (4-methoxynaphthyl) -4,6-bis (trichloromethyl) -s-triazine, 2-pheni Thio-4,6-bis (trichloromethyl) -s-triazine, 2-benzylthio-4,6-bis (trichloromethyl) -s-triazine, 2,4,6-tris (dibromomethyl) -s-triazine, 2,4,6-tris (tribromomethyl) -s-triazine, 2-methyl-4,6-bis (tribromomethyl) -s-triazine, 2-methoxy-4,6-bis (tribromomethyl) -S-triazine and the like.

  Examples of the carbonyl compound include benzophenone, Michler ketone, 2-methylbenzophenone, 3-methylbenzophenone, 4-methylbenzophenone, 2-chlorobenzophenone, 4-bromobenzophenone, benzophenone derivatives such as 2-carboxybenzophenone, 2,2-dimethoxy- 2-phenylacetophenone, 2,2-diethoxyacetophenone, 1-hydroxycyclohexyl phenyl ketone, α-hydroxy-2-methylphenylpropanone, 1-hydroxy-1-methylethyl- (p-isopropylphenyl) ketone, 1- Hydroxy-1- (p-dodecylphenyl) ketone, 2-methyl- (4 ′-(methylthio) phenyl) -2-morpholino-1-propanone, 1,1,1-trichloromethyl- (p-butylpheny ) Acetophenone derivatives such as ketones, thioxanthone derivatives such as thioxanthone, 2-ethylthioxanthone, 2-isopropylthioxanthone, 2-chlorothioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, 2,4-diisopropylthioxanthone, p Examples thereof include benzoic acid ester derivatives such as ethyl dimethylaminobenzoate and ethyl p-diethylaminobenzoate.

  As the azo compound, for example, an azo compound described in JP-A-8-108621 can be used.

  Examples of the organic peroxide include trimethylcyclohexanone peroxide, acetylacetone peroxide, 1,1-bis (tert-butylperoxy) -3,3,5-trimethylcyclohexane, 1,1-bis (tert-butyl). Peroxy) cyclohexane, 2,2-bis (tert-butylperoxy) butane, tert-butyl hydroperoxide, cumene hydroperoxide, diisopropylbenzene hydroperoxide, 2,5-dimethylhexane-2,5-dihydro Peroxide, 1,1,3,3-tetramethylbutyl hydroperoxide, tert-butylcumyl peroxide, dicumyl peroxide, 2,5-dimethyl-2,5-di (tert-butylperoxy) hexane, 2, -Oxanoyl peroxide, succinic peroxide, benzoyl peroxide, 2,4-dichlorobenzoyl peroxide, diisopropyl peroxydicarbonate, di-2-ethylhexyl peroxydicarbonate, di-2-ethoxyethyl peroxydicarbonate , Dimethoxyisopropyl peroxycarbonate, di (3-methyl-3-methoxybutyl) peroxydicarbonate, tert-butyl peroxyacetate, tert-butyl peroxypivalate, tert-butyl peroxyneodecanoate, tert- Butyl peroxyoctanoate, tert-butyl peroxylaurate, tersyl carbonate, 3,3 ′, 4,4′-tetra- (t-butylperoxycarbonyl) benzophenone, 3,3 ′, 4,4 ′ − Tra- (t-hexylperoxycarbonyl) benzophenone, 3,3 ′, 4,4′-tetra- (p-isopropylcumylperoxycarbonyl) benzophenone, carbonyldi (t-butylperoxydihydrogen diphthalate), carbonyl And di (t-hexylperoxydihydrogen diphthalate).

  Examples of the metallocene compound include JP-A-59-152396, JP-A-61-151197, JP-A-63-41484, JP-A-2-249, JP-A-2-4705, Various titanocene compounds described in JP-A-5-83588, such as di-cyclopentadienyl-Ti-bis-phenyl, di-cyclopentadienyl-Ti-bis-2,6-difluorophen-1-yl, Di-cyclopentadienyl-Ti-bis-2,4-di-fluorophen-1-yl, di-cyclopentadienyl-Ti-bis-2,4,6-trifluorophen-1-yl, di- -Cyclopentadienyl-Ti-bis-2,3,5,6-tetrafluorophen-1-yl, di-cyclopentadienyl-Ti-bis-2,3,4,5,6-penta Fluorophen-1-yl, di-methylcyclopentadienyl-Ti-bis-2,6-difluorophen-1-yl, di-methylcyclopentadienyl-Ti-bis-2,4,6-trifluoropheny -1-yl, di-methylcyclopentadienyl-Ti-bis-2,3,5,6-tetrafluorophen-1-yl, di-methylcyclopentadienyl-Ti-bis-2,3,4 , 5,6-pentafluorophen-1-yl, iron-arene complexes described in JP-A-1-304453 and JP-A-1-152109, and the like.

  Examples of the hexaarylbiimidazole compound include the specifications of JP-B-6-29285, US Pat. Nos. 3,479,185, 4,311,783, and 4,622,286. And, specifically, 2,2′-bis (o-chlorophenyl) -4,4 ′, 5,5′-tetraphenylbiimidazole, 2,2′-bis (o-bromophenyl) )) 4,4 ′, 5,5′-tetraphenylbiimidazole, 2,2′-bis (o, p-dichlorophenyl) -4,4 ′, 5,5′-tetraphenylbiimidazole, 2,2 ′ -Bis (o-chlorophenyl) -4,4 ', 5,5'-tetra (m-methoxyphenyl) biidazole, 2,2'-bis (o, o'-dichlorophenyl) -4,4', 5,5 '-Tetraphenylbiimidazole, 2, 2 '-Bis (o-nitrophenyl) -4,4', 5,5'-tetraphenylbiimidazole, 2,2'-bis (o-methylphenyl) -4,4 ', 5,5'-tetraphenyl Examples include biimidazole and 2,2′-bis (o-trifluorophenyl) -4,4 ′, 5,5′-tetraphenylbiimidazole.

  Examples of the organoboron compound include JP-A-62-143044, JP-A-62-1050242, JP-A-9-188585, JP-A-9-188686, JP-A-9-188710, JP-A 2000-. 131837, Japanese Patent Application Laid-Open No. 2002-107916, Japanese Patent No. 2764769, Japanese Patent Application Laid-Open No. 2002-116539, and Kunz, Martin “Rad Tech '98. Proceeding April 19-22, 1998, Chicago”. Organoborates described in JP-A-6-157623, JP-A-6-175564, JP-A-6-175561, and organic boron oxosulfonium complexes, JP-A-6-175554 No. 6, JP-A-6-17555 Organoboron iodonium complexes described in JP-A-9-188710, organoboron phosphonium complexes described in JP-A-9-188710, JP-A-6-348011, JP-A-7-128785, JP-A-7-140589, Examples thereof include organoboron transition metal coordination complexes such as Kaihei 7-306527 and JP-A-7-292014.

Examples of the disulfone compound include JP-A Nos. 61-166544 and 2003-3.
And compounds described in Japanese Patent No. 28465.

Examples of the oxime ester compounds include JCS Perkin II (1979) 1653-1660), JCS
Perkin II (1979) 156-162, Journal of Photopolymer Science and Technology (1995) 202-232, compounds described in JP-A No. 2000-66385, compounds described in JP-A No. 2000-80068, specifically, And a compound represented by the structural formula:

Examples of the onium salt compound include S.I. I. Schlesinger, Photogr. Sci. Eng. , 18, 387 (1974), T.A. S. Diazonium salts described in Bal et al, Polymer, 21, 423 (1980), ammonium salts described in US Pat. No. 4,069,055, JP-A-4-365049, etc., US Pat. No. 4,069 , 055, 4,069,056, phosphonium salts described in European Patent Nos. 104,143, US Pat. Nos. 339,049, 410,201, JP -150848, JP-A-2-296514, iodonium salts, European Patent Nos. 370,693, 390,214, 233,567, 297,443, and 297 442, U.S. Pat. No. 4,933,377,
161,811, 410,201, 339,049, 4,760,013, 4,734,444, 2,833,827, Germany The sulfonium salts described in the specifications of Patent Nos. 2,904,626, 3,604,580, and 3,604,581, J. Pat. V. Crivello et al, Macromolecules, 10 (6), 1307 (1977), J. MoI. V. Crivello et al, J.A. Polymer Sci. , Polymer Chem. Ed. , 17, 1047 (1979), a selenonium salt described in C.I. S. Wen et al, Teh, Proc. Conf. Rad. Curing ASIA, p478 Tokyo, Oct (1988) and onium salts such as arsonium salts.

  Particularly preferred from the standpoint of reactivity and stability are the oxime ester compounds or onium salts (diazonium salts, iodonium salts or sulfonium salts).

  The onium salts preferably used in the present invention are onium salts represented by the following general formulas (RI-I) to (RI-III).

In the formula (RI-I), Ar ₁₁ represents an aryl group having 20 or less carbon atoms which may have 1 to 6 substituents, and preferred substituents include an alkyl group having 1 to 12 carbon atoms and a carbon number. 1-12 alkenyl group, C1-C12 alkynyl group, C1-C12 aryl group, C1-C12 alkoxy group, C1-C12 aryloxy group, halogen atom, C1-C1 12 alkylamino groups, C1-C12 dialkylamino groups, C1-C12 alkylamide groups or arylamitodo groups, carbonyl groups, carboxyl groups, cyano groups, sulfonyl groups, C1-C12 thioalkyls Group, a C1-C12 thioaryl group is mentioned. Z ₁₁ ^- represents a monovalent anion, specifically a halogen ion, perchlorate ion, hexafluorophosphate ion, tetrafluoroborate ion, sulfonate ion, sulfinate ion, thiosulfonate ion, a sulfate ion Can be mentioned. Among these, from the viewpoint of stability, perchlorate ion, hexafluorophosphate ion, tetrafluoroborate ion, sulfonate ion and sulfinate ion are preferable.

In formula (RI-II), Ar ₂₁ and Ar ₂₂ each independently represent an aryl group having 20 or less carbon atoms which may have 1 to 6 substituents, and preferred substituents include 1 to 1 carbon atoms. 12 alkyl groups, an alkenyl group having 1 to 12 carbon atoms, an alkynyl group having 1 to 12 carbon atoms, an aryl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, an aryloxy group having 1 to 12 carbon atoms, Halogen atom, C1-C12 alkylamino group, C1-C12 dialkylamino group, C1-C12 alkylamide group or arylamide group, carbonyl group, carboxyl group, cyano group, sulfonyl group, carbon Examples thereof include a thioalkyl group having 1 to 12 carbon atoms and a thioaryl group having 1 to 12 carbon atoms. Z ₂₁ ^- represents a monovalent anion. Specific examples include halogen ions, perchlorate ions, hexafluorophosphate ions, tetrafluoroborate ions, sulfonate ions, sulfinate ions, thiosulfonate ions, and sulfate ions. Among these, perchlorate ion, hexafluorophosphate ion, tetrafluoroborate ion, sulfonate ion, sulfinate ion, and carboxylate ion are preferable from the viewpoint of stability and reactivity.

In the formula (RI-III), R ₃₁ , R ₃₂ and R ₃₃ are each independently an aryl group, alkyl group, alkenyl group or alkynyl having 20 or less carbon atoms, which may have 1 to 6 substituents. Represents a group. Among them, an aryl group is preferable from the viewpoint of reactivity and stability. Examples of the substituent include an alkyl group having 1 to 12 carbon atoms, an alkenyl group having 1 to 12 carbon atoms, an alkynyl group having 1 to 12 carbon atoms, an aryl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, Aryloxy group having 1 to 12 carbon atoms, halogen atom, alkylamino group having 1 to 12 carbon atoms, dialkylamino group having 1 to 12 carbon atoms, alkylamide group or arylamide group having 1 to 12 carbon atoms, carbonyl group, carboxyl Group, a cyano group, a sulfonyl group, a thioalkyl group having 1 to 12 carbon atoms, and a thioaryl group having 1 to 12 carbon atoms. Z ₃₁ ^- represents a monovalent anion. Specific examples include halogen ions, perchlorate ions, hexafluorophosphate ions, tetrafluoroborate ions, sulfonate ions, sulfinate ions, thiosulfonate ions, sulfate ions, and carboxylate ions. Among these, perchlorate ion, hexafluorophosphate ion, tetrafluoroborate ion, sulfonate ion, sulfinate ion, and carboxylate ion are preferable from the viewpoints of stability and reactivity. More preferred are the carboxylate ions described in JP-A No. 2001-343742, and particularly preferred are the carboxylate ions described in JP-A No. 2002-148790.

  Although the specific example of the onium salt compound suitable for this invention is given to the following, it is not limited to these.

These polymerization initiators are added in a proportion of 0.1 to 50% by mass, preferably 0.5 to 30% by mass, particularly preferably 1 to 20% by mass, based on the total solid content constituting the image recording layer. Can do. Within this range, good sensitivity and good stain resistance of the non-image area during printing can be obtained. These polymerization initiators may be used alone or in combination of two or more. Moreover, these polymerization initiators may be added to the same layer as other components, or another layer may be provided and added thereto.

<Binder polymer>
The image recording layer of the present invention can contain a binder polymer for improving the film property 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 a linear organic polymer having a film property is preferable. Examples of such binder polymers include acrylic resins, polyvinyl acetal resins, polyurethane resins, polyurea resins, polyimide resins, polyamide resins, epoxy resins, methacrylic resins, polystyrene resins, novolac phenolic resins, polyester resins, and synthetic rubbers. And natural rubber.

  The binder polymer preferably has crosslinkability in order to improve the film strength of the image area. In order to impart crosslinkability to the binder polymer, a crosslinkable functional group such as an ethylenically unsaturated bond may be introduced into the main chain or side chain of the polymer. The crosslinkable functional group may be introduced by copolymerization.

Examples of the polymer having an ethylenically unsaturated bond in the main chain of the molecule include poly-1,4-butadiene and poly-1,4-isoprene.
Examples of polymers having an ethylenically unsaturated bond in the side chain of the molecule are polymers of esters or amides of acrylic acid or methacrylic acid, where the ester or amide residue (-COOR or CONHR R) is ethylene. Examples thereof include polymers having a polymerizable unsaturated bond.

Examples of the residue (the R) having an ethylenically unsaturated _{bond, - (CH 2) n CR} 1 = CR 2 R 3, - (CH 2 O) n CH 2 CR 1 = CR 2 R 3, - _{(CH 2 CH 2 O) n} CH 2 CR 1 = CR 2 R 3, - (CH 2) n NH-CO-O-CH 2 CR 1 = CR 2 R 3, - (CH 2) n -O-CO —CR ¹ ═CR ² R ³ and (CH ₂ CH ₂ O) ₂ —X (wherein R ^{1 to} R ³ are each a hydrogen atom, a halogen atom, or an alkyl group having 1 to 20 carbon atoms, an aryl group, and alkoxy. R ¹ and R ² or R ³ may be bonded to each other to form a ring, n represents an integer of 1 to 10. X represents a dicyclopentadienyl residue. Represents a group).

Specific examples of the ester _{residue, -CH 2 CH = CH 2,} ( described in JP Kokoku _{7-21633.) - CH 2 CH 2} O-CH 2 CH = CH 2, -CH 2 C _{(CH 3) = CH 2,} -CH 2 CH = CH-C 6 H 5, -CH 2 CH 2 OCOCH = CH-C 6 H 5, -CH 2 CH 2 -NHCOO-CH 2 CH = CH 2 and CH ₂ CH ₂ O—X (wherein X represents a dicyclopentadienyl residue).
Specific examples of the amide residue include —CH ₂ CH═CH ₂ , —CH ₂ CH ₂ —Y (wherein Y represents a cyclohexene residue), —CH ₂ CH ₂ —OCO—CH═CH _2. Is mentioned.

  The binder polymer having crosslinkability, for example, has a free radical (polymerization initiation radical or a growth radical in the polymerization process of the polymerizable compound) added to the crosslinkable functional group, and the polymerization chain of the polymerizable compound is formed directly between the polymers. Through addition polymerization, a cross-link is formed between the polymer molecules and cured. Alternatively, atoms in the polymer (eg, hydrogen atoms on carbon atoms adjacent to the functional bridging group) are abstracted by free radicals to form polymer radicals that are bonded together, thereby causing cross-linking between polymer molecules. Forms and cures.

The content of the crosslinkable group in the binder polymer (content of unsaturated double bond capable of radical polymerization by iodine titration) is preferably 0.1 to 10.0 mmol, more preferably 1.0, per 1 g of the binder polymer. -7.0 mmol, most preferably 2.0-5.5 mmol. Within this range, good sensitivity and good storage stability can be obtained.

  The binder polymer may be any of a random polymer, a block polymer, and a graft polymer, but a random polymer is more preferable. Moreover, a binder polymer may be used independently or may be used in mixture of 2 or more types.

From the viewpoint of improving on-press developability, the binder polymer preferably has high solubility or dispersibility in ink and / or fountain solution.
In order to improve solubility or dispersibility in ink, the binder polymer is preferably oleophilic, and in order to improve solubility or dispersibility in dampening water, the binder polymer is hydrophilic. Is preferred. It is also effective to use a lipophilic binder polymer and a hydrophilic binder polymer in combination. Which binder polymer is used is determined in consideration of the components other than the binder polymer of the image recording layer.

  Examples of hydrophilic binder polymers include hydroxy groups, carboxyl groups, carboxylate groups, hydroxyethyl groups, polyoxyethyl groups, hydroxypropyl groups, polyoxypropyl groups, amino groups, aminoethyl groups, aminopropyl groups, and ammonium. Preferred are those having a hydrophilic group such as a group, an amide group, a carboxymethyl group, a sulfonic acid group, and a phosphoric acid group.

  Specific examples include gum arabic, casein, gelatin, starch derivatives, carboxymethylcellulose and its sodium salt, cellulose acetate, sodium alginate, vinyl acetate-maleic acid copolymers, styrene-maleic acid copolymers, polyacrylic acids and their salts, Polymethacrylic acids and their salts, hydroxyethyl methacrylate homopolymers and copolymers, hydroxyethyl acrylate homopolymers and copolymers, hydroxypropyl methacrylate homopolymers and copolymers, hydroxypropyl acrylate homopolymers and copolymers, hydroxybutyl methacrylate homopolymers Polymers and copolymers, homopolymers and copolymers of hydroxybutyl acrylate, polyethylene glycol , Hydroxypropylene polymers, polyvinyl alcohols, hydrolyzed polyvinyl acetate, polyvinyl formal, polyvinyl butyral, polyvinyl pyrrolidone, acrylamide homopolymers and copolymers having a hydrolysis degree of 60 mol% or more, preferably 80 mol% or more Methacrylamide homopolymers and polymers, N-methylolacrylamide homopolymers and copolymers, polyvinylpyrrolidone, alcohol-soluble nylon, polyether of 2,2-bis- (4-hydroxyphenyl) -propane and epichlorohydrin, etc. Is mentioned.

  The hydrophilic binder polymer may be used after being crosslinked to such an extent that on-press development is not impaired. Cross-linking agents include glyoxal, aldehydes such as melamine formaldehyde resin, urea formaldehyde resin, methylol compounds such as N-methylol urea, N-methylol melamine, and methylolated polyamide resin, divinyl sulfone and bis (β-hydroxyethylsulfonic acid) Active vinyl compounds such as, epoxy compounds such as epichlorohydrin and polyethylene glycol diglycidyl ether, polyamides, polyamines, epichlorohydrin adducts, polyamide epichlorohydrin resins, ester compounds such as monochloroacetic acid esters and thioglycolic acid esters, Polycarboxylic acids such as polyacrylic acid and methyl vinyl ether / maleic acid copolymer, inorganic such as boric acid, titanyl sulfate, Cu, Al, Sn, V, Cr salts Crosslinking agents, such as modified polyamide polyimide resin. In addition, a crosslinking catalyst such as ammonium chloride, a silane coupling agent, a titanate coupling agent, or the like can be used in combination.

  The binder polymer preferably has a weight average molecular weight of 5000 or more, more preferably 10,000 to 300,000, and a number average molecular weight of 1,000 or more, preferably 2000 to 250,000. More preferred. The polydispersity (weight average molecular weight / number average molecular weight) is preferably 1.1 to 10.

The content of the binder polymer is 10 to 90% by mass, preferably 20 to 80% by mass, and more preferably 30 to 70% by mass with respect to the total solid content of the image recording layer. Within this range, good image area strength and image formability can be obtained.
Moreover, it is preferable to use a polymeric compound and a binder polymer in the quantity used as 1 / 9-7 / 3 by mass ratio.

<Other image recording layer components>
In the image recording layer of the present invention, a compound that changes color by an acid or a radical can be added to produce a printout image. As such a compound, for example, various dyes such as diphenylmethane, triphenylmethane, thiazine, oxazine, xanthene, anthraquinone, iminoquinone, azo, and azomethine are effectively used.

  Specific examples include brilliant green, ethyl violet, methyl green, crystal violet, basic fuchsin, methyl violet 2B, quinaldine red, rose bengal, methanyl yellow, thymol sulfophthalein, xylenol blue, methyl orange, paramethyl red, Congo Fred, Benzopurpurin 4B, α-Naphthyl Red, Nile Blue 2B, Nile Blue A, Methyl Violet, Malachide Green, Parafuchsin, Victoria Pure Blue BOH [manufactured by Hodogaya Chemical Co., Ltd.], Oil Blue # 603 [Orient Chemical Kogyo Co., Ltd.], Oil Pink # 312 [Orient Chemical Co., Ltd.], Oil Red 5B [Orient Chemical Co., Ltd.], Oil Scarlet # 308 [Orient Gaku Kogyo Co., Ltd.], Oil Red OG [Orient Chemical Co., Ltd.], Oil Red RR [Orient Chemical Co., Ltd.], Oil Green # 502 [Orient Chemical Co., Ltd.], Spiron Red BEH Special [made by Hodogaya Chemical Co., Ltd.], m-cresol purple, cresol red, rhodamine B, rhodamine 6G, sulforhodamine B, auramine, 4-p-diethylaminophenyliminonaphthoquinone, 2-carboxyanilino-4-p- Diethylaminophenyliminonaphthoquinone, 2-carboxystearylamino-4-pN, N-bis (hydroxyethyl) amino-phenyliminonaphthoquinone, 1-phenyl-3-methyl-4-p-diethylaminophenylimino-5-pyrazolone, 1-β-naphthyl-4- - dyes and p of diethylamino phenyl imino-5-pyrazolone, p ', p "- hexamethyl triamnotriphenylmethane (leuco crystal violet), and a leuco dye such as Pergascript Blue SRB (manufactured by Ciba-Geigy).

In addition to the above, a leuco dye known as a material for thermal paper or pressure-sensitive paper is also suitable. Specific examples include crystal violet lactone, malachite green lactone, benzoylleucomethylene blue, 2- (N-phenyl-N-methylamino) -6- (Np-tolyl-N-ethyl) amino-fluorane, 2-anilino. -3-methyl-6- (N-ethyl-p-toluidino) fluorane, 3,6-dimethoxyfluorane, 3- (N, N-diethylamino) -5-methyl-7- (N, N-dibenzylamino) ) -Fluorane, 3- (N-cyclohexyl-N-methylamino) -6-methyl-7-anilinofluorane, 3- (N, N-diethylamino) -6-methyl-7-anilinofluorane, 3 -(N, N-diethylamino) -6-methyl-7-xylidinofluorane, 3- (N, N-diethylamino) -6-methyl-7-chloro Fluoran, 3- (N, N-diethylamino) -6-methoxy-7- aminofluoran, 3- (N, N-diethylamino) -7- (
4-chloroanilino) fluorane, 3- (N, N-diethylamino) -7-chlorofluorane, 3- (N, N-diethylamino) -7-benzylaminofluorane, 3- (N, N-diethylamino) -7 , 8-Benzofluorane, 3- (N, N-dibutylamino) -6-methyl-7-anilinofluorane, 3- (N, N-dibutylamino) -6-methyl-7-xylidinofluorane 3-piperidino-6-methyl-7-anilinofluorane, 3-pyrrolidino-6-methyl-7-anilinofluorane, 3,3-bis (1-ethyl-2-methylindol-3-yl) Phthalide, 3,3-bis (1-n-butyl-2-methylindol-3-yl) phthalide, 3,3-bis (p-dimethylaminophenyl) -6-dimethylaminophthalide, 3- ( -Diethylamino-2-ethoxyphenyl) -3- (1-ethyl-2-methylindol-3-yl) -4-zaphthalide, 3- (4-diethylaminophenyl) -3- (1-ethyl-2-methylindole) -3-yl) phthalide, and the like.

  A suitable addition amount of the dye that changes color by an acid or a radical is 0.01 to 10% by mass with respect to the solid content of the image recording layer.

  In addition to the above, various compounds may be added to the image recording layer of the present invention as necessary. For example, a polyfunctional monomer can be added to the image recording layer matrix in order to further improve the printing durability. As this polyfunctional monomer, those exemplified as the monomer put in the microcapsule or microgel can be used. Among them, preferable monomers include trimethylolpropane triacrylate, pentaerythritol triacrylate, and the like.

  In the present invention, it is desirable to add a small amount of a thermal polymerization inhibitor in order to prevent unnecessary thermal polymerization of the ethylenically unsaturated compound during preparation or storage of the image recording layer coating solution. Suitable thermal polymerization inhibitors include hydroquinone, p-methoxyphenol, di-t-butyl-p-cresol, pyrogallol, t-butylcatechol, benzoquinone, 4,4'-thiobis (3-methyl-6-t-butylphenol ), 2,2'-methylenebis (4-methyl-6-t-butylphenol), N-nitroso-N-phenylhydroxylamine aluminum salt and the like. The addition amount of the thermal polymerization inhibitor is preferably 0.01 to 5% by mass with respect to the weight of the total composition.

  If necessary, higher fatty acids such as behenic acid and behenic acid amide or derivatives thereof are added to prevent polymerization inhibition due to oxygen, and are unevenly distributed on the surface of the image recording layer in the drying process after coating. May be. The amount of the higher fatty acid or derivative thereof added is preferably 0.1 to about 10% by mass based on the solid content of the image recording layer.

  In addition, inorganic fine particles may be added to the image recording layer of the present invention, and suitable examples of the inorganic fine particles include silica, alumina, magnesium oxide, titanium oxide, magnesium carbonate, calcium alginate or a mixture thereof. Even if they are not photothermally convertible, they can be used for strengthening the film and enhancing interfacial adhesion by surface roughening.

  The average particle size of the inorganic fine particles is preferably 5 nm to 10 μm, more preferably 10 nm to 1 μm. Within this range, both the resin fine particles and the photothermal conversion metal fine particles are stably dispersed in the hydrophilic resin, the film strength of the image recording layer is sufficiently maintained, and the hydrophilicity is less likely to cause printing stains. A non-image part can be formed.

  Such inorganic fine particles can be easily obtained as a commercial product such as a colloidal silica dispersion. The content of the inorganic fine particles in the image recording layer is preferably 20% by mass or less, more preferably 10% by mass or less, based on the total solid content of the image recording layer.

  In the image recording layer of the present invention, JP-A-2-195356, JP-A-59-121044 and JP-A-4 are used for improving the dispersion stability, plate making and printing performance, and coating properties of the image recording layer. Nonionic, anionic, cationic, amphoteric or fluorine surfactants described in JP-A-13149 and Japanese Patent Application No. 2001-169731 can be added. A suitable addition amount of these surfactants is 0.005 to 1% by mass of the total solids of the image recording layer.

  Furthermore, a plasticizer can be added to the image recording layer of the present invention, if necessary, in order to impart flexibility of the coating film. For example, polyethylene glycol, tributyl citrate, diethyl phthalate, dibutyl phthalate, dihexyl phthalate, dioctyl phthalate, tricresyl phosphate, tributyl phosphate, trioctyl phosphate, tetrahydrofurfuryl oleate and the like are used.

  The image recording layer of the present invention is applied by preparing a coating solution by dissolving the necessary components described above in a solvent. Solvents used here include ethylene dichloride, cyclohexanone, methyl ethyl ketone, methanol, ethanol, propanol, ethylene glycol monomethyl ether, 1-methoxy-2-propanol, 2-methoxyethyl acetate, 1-methoxy-2-propyl acetate, dimethoxy Examples include ethane, methyl lactate, ethyl lactate, N, N-dimethylacetamide, N, N-dimethylformamide, tetramethylurea, N-methylpyrrolidone, dimethyl sulfoxide, sulfolane, γ-butyllactone, toluene, water, and the like. However, the present invention is not limited to this. These solvents are used alone or in combination. The solid content concentration of the coating solution is preferably 1 to 50% by mass.

Further, the coating amount (solid content) of the image recording layer on the support obtained after coating and drying varies depending on the use, but generally 0.5 to 5.0 g / m ² is preferable. When the coating amount is less than this range, the apparent sensitivity increases, but the film characteristics of the image recording layer that performs the image recording function are deteriorated. Various methods can be used as a coating method. Examples thereof include bar coater coating, spin coating, spray coating, curtain coating, dip coating, air knife coating, blade coating, and roll coating.

[Support]
The support on which the image recording layer can be applied in the planographic printing plate precursor of the present invention is a dimensionally stable plate-like material, for example, paper, plastic (for example, polyethylene, polypropylene, polystyrene, etc.) is laminated. Paper, metal plates (eg, aluminum, zinc, copper, etc.), plastic films (eg, cellulose diacetate, cellulose triacetate, cellulose propionate, cellulose butyrate, cellulose acetate butyrate, cellulose nitrate, polyethylene terephthalate, polyethylene, polystyrene) , Polypropylene, polycarbonate, polyvinyl acetal, etc.), paper or plastic film on which a metal as described above is laminated or vapor-deposited. A preferable support includes a polyester film or an aluminum plate.

  The aluminum plate is a pure aluminum plate and an alloy plate containing aluminum as a main component and containing a trace amount of different elements. Further, a plastic is laminated on a thin film of aluminum or an aluminum alloy. Examples of foreign elements contained in the aluminum alloy include silicon, iron, manganese, copper, magnesium, chromium, zinc, bismuth, nickel, and titanium. The content of foreign elements in the alloy is at most 10% by mass. Further, it may be an aluminum plate from an aluminum ingot using a DC casting method or an aluminum plate from an ingot by a continuous casting method. However, as the aluminum plate applied to the present invention, conventionally known and publicly available aluminum plates can be used as appropriate.

  The thickness of the substrate used in the present invention is preferably 0.05 mm to 0.6 mm, more preferably 0.1 mm to 0.4 mm, and particularly preferably 0.15 mm to 0.3 mm.

  Prior to using the aluminum plate, it is preferable to perform a surface treatment such as roughening the surface or anodizing. By the surface treatment, it becomes easy to improve hydrophilicity and secure adhesion to the image recording layer.

  The surface of the aluminum plate is roughened by various methods. For example, a method of mechanically roughening, a method of electrochemically dissolving and roughening the surface, and a method of selectively dissolving the surface chemically. By the method. As the mechanical method, a known method such as a ball polishing method, a brush polishing method, a blast polishing method, or a buff polishing method can be used. As a chemical method, a method of immersing in a saturated aqueous solution of an aluminum salt of a mineral acid as described in JP-A No. 54-31187 is suitable. In addition, as an electrochemical surface roughening method, there is a method of performing alternating current or direct current in an electrolytic solution containing an acid such as hydrochloric acid or nitric acid. Further, as disclosed in JP-A-54-63902, an electrolytic surface roughening method using a mixed acid can also be used. The roughening by the method as described above is preferably performed in such a range that the center line average roughness (Ra) of the surface of the aluminum plate is 0.2 to 1.0 μm.

  The roughened aluminum plate is subjected to alkali etching treatment using an aqueous solution of potassium hydroxide or sodium hydroxide as necessary, and further neutralized, and then anodized to increase wear resistance as desired. Processing is performed.

As the electrolyte used for the anodizing treatment of the aluminum plate, various electrolytes that form a porous oxide film can be used. In general, sulfuric acid, hydrochloric acid, oxalic acid, chromic acid, or a mixed acid thereof is used. The concentration of these electrolytes is appropriately determined depending on the type of electrolyte. The treatment conditions for anodization vary depending on the electrolyte used, and thus cannot be specified in general. However, in general, the electrolyte concentration is 1 to 80% by mass solution, the liquid temperature is 5 to 70 ° C., and the current density is 5 to 60 A / day. dm ² , voltage 1 to 100 V, and electrolysis time 10 seconds to 5 minutes are suitable. The amount of the oxide film to be formed is preferably 1.0 to 5.0 g / m ² , particularly 1.5 to 4.0 g / m ² .

  As the support used in the present invention, the substrate having the above-mentioned surface treatment and having an anodized film may be used as it is, but for further improvement in adhesion to the upper layer, hydrophilicity, resistance to contamination, heat insulation and the like. If necessary, an aqueous solution containing an anodized film micropore enlargement treatment, micropore sealing treatment, and a hydrophilic compound described in JP-A Nos. 2001-253181 and 2001-322365 The surface hydrophilization treatment to be immersed can be appropriately selected and performed.

  Suitable hydrophilic compounds for the hydrophilization treatment include polyvinylphosphonic acid, sulfonic acid group-containing compounds, saccharide compounds, citric acid, alkali metal silicates, potassium zirconium fluoride, phosphate / inorganic fluorine compounds, and the like. Can be mentioned.

  When using a support with insufficient surface hydrophilicity such as a polyester film as the support of the present invention, it is desirable to apply a hydrophilic layer to make the surface hydrophilic. The hydrophilic layer includes at least one element selected from beryllium, magnesium, aluminum, silicon, titanium, boron, germanium, tin, zirconium, iron, vanadium, antimony, and a transition metal described in JP-A No. 2001-199175. A hydrophilic layer formed by applying a coating solution containing an oxide or hydroxide colloid is preferred. Among these, a hydrophilic layer formed by applying a coating solution containing a silicon oxide or hydroxide colloid is preferable.

(Undercoat layer)
In the lithographic printing plate precursor according to the invention, an undercoat layer can be provided between the image recording layer and the support, if necessary. Since the undercoat layer tends to cause the image recording layer to peel off from the support in the unexposed area, the on-press developability is improved. In addition, in the case of infrared laser exposure, since the undercoat layer functions as a heat insulating layer, heat generated by the exposure does not diffuse to the support and can be used efficiently, so that high sensitivity can be achieved. There are advantages. Specific examples of the undercoat layer compound (undercoat compound) include silane coupling agents having an addition-polymerizable ethylenic double bond reactive group described in JP-A-10-282679, Preferable examples include phosphorus compounds having an ethylenic double bond reactive group described in Kaihei 2-304441.
As the most preferable undercoat compound, a polymer resin obtained by copolymerizing a monomer having an adsorptive group / a monomer having a hydrophilic group / a monomer having a crosslinkable group may be mentioned.

An essential component of the polymer undercoat is an adsorptive group on the surface of the hydrophilic support. The presence or absence of adsorptivity on the surface of the hydrophilic support can be determined by the following method, for example.
A coating night is prepared by dissolving the test compound in a readily soluble solvent, and the coating night is coated and dried on the support so that the coating amount after drying is 30 mg / m ² . Next, the support coated with the test compound is sufficiently washed with a readily soluble solvent, and then the residual amount of the test compound that has not been removed by washing is measured to calculate the adsorbed amount of the support. Here, the measurement of the remaining amount may be performed by directly quantifying the amount of the remaining compound or by quantifying the amount of the test compound dissolved in the cleaning liquid. The compound can be quantified by, for example, fluorescent X-ray measurement, reflection spectral absorbance measurement, liquid chromatography measurement and the like. The compound having support adsorptivity is a compound that remains at 1 mg / m ² or more even after the above-described washing treatment.

The adsorptive group on the surface of the hydrophilic support is a substance (for example, metal, metal oxide) or a functional group (for example, hydroxyl group) existing on the surface of the hydrophilic support and a chemical bond (for example, ionic bond, hydrogen bond). , Coordination bond, bond by intermolecular force). The adsorptive group is preferably an acid group or a cationic group.
The acid group preferably has an acid dissociation constant (pKa) of 7 or less. Examples of acid groups are phenolic hydroxyl groups, carboxyl groups, —SO ₃ H, —OSO ₃ H, —PO ₃ H ₂ , —OPO ₃ H ₂ , —CONHSO ₂ —, —SO ₂ NHSO ₂ — and COCH ₂ COCH. Including ₃ . Of these, -OPO ₃ H ₂ and PO ₃ H ₂ are particularly preferable. These acid groups may be metal salts. The cationic group is preferably an onium group. Examples of the onium group include an ammonium group, a phosphonium group, an arsonium group, a stibonium group, an oxonium group, a sulfonium group, a selenonium group, a stannonium group, and an iodonium group. An ammonium group, a phosphonium group and a sulfonium group are preferred, an ammonium group and a phosphonium group are more preferred, and an ammonium group is most preferred.

  Particularly preferred examples of the monomer having an adsorptive group include compounds represented by the following formula (II) or (III).

In the formula, each of R ¹ , R ² and R ³ independently represents a hydrogen atom, a halogen atom or an alkyl group having 1 to 6 carbon atoms, and X represents an oxygen atom (—O—) or imino (— NH-), L represents a divalent linking group, Z represents a functional group adsorbed on the surface of the hydrophilic support, and Y represents a carbon atom or a nitrogen atom.

In the formula (II), R ¹ , R ² and R ³ are each independently a hydrogen atom, a halogen atom or an alkyl group having 1 to 6 carbon atoms. R ¹ , R ² and R ³ are each independently preferably a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, and preferably a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. More preferred is a hydrogen atom or a methyl group. R ² and R ³ are particularly preferably a hydrogen atom.
In the formula (II), X is an oxygen atom (—O—) or imino (—NH—). X is more preferably an oxygen atom. In the formula (II), L is a divalent linking group. L is a divalent aliphatic group (alkylene group, substituted alkylene group, alkenylene group, substituted alkenylene group, alkynylene group, substituted alkynylene group), divalent aromatic group (arylene group, substituted arylene group) or divalent Or an oxygen atom (—O—), a sulfur atom (—S—), an imino (—NH—), a substituted imino (—NR—, where R is an aliphatic group, an aromatic group. Or a heterocyclic group) or a combination with carbonyl (—CO—).

The aliphatic group may have a cyclic structure or a branched structure. The number of carbon atoms in the aliphatic group is preferably 1 to 20, more preferably 1 to 15, and most preferably 1 to 10. The aliphatic group is preferably a saturated aliphatic group rather than an unsaturated aliphatic group. The aliphatic group may have a substituent. Examples of the substituent include a halogen atom, a hydroxyl group, an aromatic group, and a heterocyclic group.
The number of carbon atoms in the aromatic group is preferably 6 to 20, more preferably 6 to 15, and most preferably 6 to 10. The aromatic group may have a substituent. Examples of the substituent include a halogen atom, a hydroxyl group, an aliphatic group, an aromatic group, and a heterocyclic group. The heterocyclic group preferably has a 5-membered or 6-membered ring as the heterocycle. Another heterocyclic ring, an aliphatic ring or an aromatic ring may be condensed with the heterocyclic ring. The heterocyclic group may have a substituent. Examples of substituents include halogen atoms, hydroxyl groups, oxo groups (═O), thioxo groups (═S), imino groups (═NH), substituted imino groups (═N—R, R is an aliphatic group, aromatic Group or heterocyclic group), aliphatic group, aromatic group and heterocyclic group.
L is preferably a divalent linking group containing a plurality of polyoxyalkylene structures. The polyoxyalkylene structure is more preferably a polyoxyethylene structure. In other words, L preferably contains — (OCH ₂ CH ₂ ) _n — (n is an integer of 2 or more).
Z is a functional group that adsorbs to the surface of the hydrophilic support. Y is a carbon atom or a nitrogen atom. When Y is a nitrogen atom and L is connected to Y to form a quaternary pyridinium group, Z is not essential because it exhibits adsorptivity itself.

  Examples of typical monomers represented by the formula (II) or (III) are shown below.

Examples of the hydrophilic group of the undercoat polymer resin that can be used in the present invention include a hydroxy group, a carboxyl group, a carboxylate group, a hydroxyethyl group, a polyoxyethyl group, a hydroxypropyl group, a polyoxypropyl group, and an amino group. Preferred examples include a group, aminoethyl group, aminopropyl group, ammonium group, amide group, carboxymethyl group, sulfonic acid group, and phosphoric acid group. Among them, a monomer having a sulfonic acid group exhibiting high hydrophilicity is preferable. Specific examples of the monomer having a sulfonic acid group include methallyloxybenzenesulfonic acid, allyloxybenzenesulfonic acid, allylsulfonic acid, vinylsulfonic acid, allylsulfonic acid, p-styrenesulfonic acid, methallylsulfonic acid, acrylamide t -Sodium sulfonic acid, 2-acrylamido-2-methylpropane sulfonic acid, sodium salt of (3-acryloyloxypropyl) butyl sulfonic acid, and amine salt. Among them, 2-acrylamido-2-methylpropanesulfonic acid sodium salt is preferable in view of hydrophilic performance and handling of synthesis.

  The water-soluble polymer resin for the undercoat layer of the present invention preferably has a crosslinkable group. The crosslinkable group can improve the adhesion with the image area. In order to make the polymer resin for the undercoat layer crosslinkable, a crosslinkable functional group such as an ethylenically unsaturated bond is introduced into the side chain of the polymer, or the polar substituent of the polymer resin is countercharged. Or a compound having an ethylenically unsaturated bond may be introduced by forming a salt structure.

  Examples of polymers having an ethylenically unsaturated bond in the side chain of the molecule are polymers of esters or amides of acrylic acid or methacrylic acid, where the ester or amide residue (R of -COOR or CONHR) is ethylene. Examples thereof include polymers having a polymerizable unsaturated bond.

Examples of the residue (the R) having an ethylenically unsaturated _{bond, - (CH 2) n CR} 1 = CR 2 R 3, - (CH 2 O) n CH 2 CR 1 = CR 2 R 3, - _{(CH 2 CH 2 O) n} CH 2 CR 1 = CR 2 R 3, - (CH 2) n NH-CO-O-CH 2 CR 1 = CR 2 R 3, - (CH 2) n -O-CO —CR ₁ ═CR ₂ R ₃ and (CH ₂ CH ₂ O) ₂ —X (wherein R _{1 to} R ₃ are each a hydrogen atom, a halogen atom or an alkyl group having 1 to 20 carbon atoms, an aryl group, Represents an alkoxy group or an aryloxy group, and R ₁ and R ₂ or R ₃ may combine with each other to form a ring, n represents an integer of 1 to 10. X represents dicyclopentadienyl. Represents a residue).
Specific examples of the ester _{residue, -CH 2 CH = CH 2,} ( described in JP Kokoku _{7-21633.) - CH 2 CH 2} O-CH 2 CH = CH 2, -CH 2 C _{(CH 3) = CH 2,} -CH 2 CH = CH-C 6 H 5, -CH 2 CH 2 OCOCH = CH-C 6 H 5, -CH 2 CH 2 NHCOO-CH 2 CH = CH 2, and CH ₂ CH ₂ O—X (wherein X represents a dicyclopentadienyl residue).
Specific examples of the amide residue include —CH ₂ CH═CH ₂ , —CH ₂ CH ₂ O—Y (wherein Y represents a cyclohexene residue), —CH ₂ CH ₂ OCO—CH═CH _2. Is mentioned. As the monomer having a crosslinkable group of the polymer resin for the undercoat layer, an ester or amide of acrylic acid or methacrylic acid having the crosslinkable group is preferable.

  The content of the crosslinkable group in the polymer resin for the undercoat layer (content of unsaturated double bond capable of radical polymerization by iodine titration) is preferably 0.1 to 10.0 mmol per 1 g of the polymer resin. Preferably it is 1.0-7.0 mmol, Most preferably, it is 2.0-5.5 mmol. Within this range, both good sensitivity and dirtiness and good storage stability can be obtained.

The polymer resin for the undercoat layer preferably has a mass average molecular weight of 5000 or more, more preferably 10,000 to 300,000, and a number average molecular weight of 1000 or more, preferably 2000 to 25 More preferably, it is 10,000. The polydispersity (mass average molecular weight / number average molecular weight) is preferably 1.1 to 10.
The polymer resin for the undercoat layer may be any of a random polymer, a block polymer, a graft polymer, and the like, but is preferably a random polymer.

The undercoat polymer resin may be used alone or in combination of two or more. The undercoat layer coating solution is obtained by dissolving the above-described undercoat polymer in an organic solvent (for example, methanol, ethanol, acetone, methyl ethyl ketone, etc.) and / or water. The undercoat layer coating solution may contain an infrared absorber. 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.

[Overcoat layer]
The lithographic printing plate precursor according to the present invention is provided on the image recording layer in order to protect the hydrophilic image recording layer surface from contamination with lipophilic substances during storage and fingerprint trace contamination due to finger contact during handling. An overcoat layer containing a water-soluble resin described in JP-A No. 2001-162961 and JP-A No. 2002-19318 can be provided.

  Specific examples of water-soluble resins used in the overcoat layer include natural gums such as gum arabic, water-soluble soybean polysaccharide, fiber derivatives (eg, carboxymethyl cellulose, carboxyethyl cellulose, methyl cellulose, etc.), modified products thereof, For synthetic polymers such as white dextrin, pullulan, and enzymatically degraded etherified dextrin, polyvinyl alcohol (polyvinyl acetate having a hydrolysis rate of 65 mol% or more), polyacrylic acid, its alkali metal salt or amine salt, polyacrylic acid Copolymer, its alkali metal salt or amine salt, polymethacrylic acid, its alkali metal salt or amine salt, vinyl alcohol / acrylic acid copolymer and its alkali metal salt or amine salt, polyacrylamide, its copolymer, poly Hydroxyethyl acrylate, poly Vinylpyrrolidone, copolymer thereof, polyvinyl methyl ether, vinyl methyl ether / maleic anhydride copolymer, poly-2-acrylamido-2-methyl-1-propanesulfonic acid, alkali metal salt or amine salt thereof, poly-2 -Acrylamido-2-methyl-1-propanesulfonic acid copolymer, its alkali metal salt or amine salt. Depending on the purpose, two or more of these resins may be mixed and used. However, the present invention is not limited to these examples.

  The overcoat layer of the present invention may contain an inorganic layered compound such as mica described in JP-A No. 11-38633. The overcoat layer can contain an infrared absorber to improve sensitivity. Preferable infrared absorbers include water-soluble infrared absorbing dyes.

  The overcoat layer coating solution is prepared by dissolving or dispersing the above components in water or a mixed solvent with a water-miscible low-boiling organic solvent (for example, methanol, ethanol, acetone, methyl ethyl ketone, etc.). In order to ensure the uniformity of coating, a nonionic surfactant can be mainly added to the coating solution in the case of aqueous solution coating. Specific examples of such nonionic surfactants include sorbitan tristearate, sorbitan monopalmitate, sorbitan trioleate, stearic acid monoglyceride, polyoxyethylene nonylphenyl ether, polyoxyethylene dodecyl ether and the like. . The proportion of the nonionic surfactant in the overcoat layer in the total solid is preferably 0.05 to 5 mass%, more preferably 1 to 3 mass%.

  Furthermore, the overcoat layer can contain a compound having any one of fluorine atoms and silicon atoms described in JP-A No. 2001-341448 in order to prevent sticking between plates during stacking and storage.

  0.1-4.0 micrometers is preferable and, as for the thickness of the overcoat layer of this invention, 0.1-1.0 micrometer is more preferable. Within this range, contamination of the image recording layer with an oleophilic substance can be prevented without impairing the removability of the overcoat layer on the printing press.

  EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited to these.

1. Manufacture of lithographic printing plate precursor (1) Manufacture of support In order to remove rolling oil on the surface of a 0.3 mm thick aluminum plate (material 1050), 10 mass% sodium aluminate aqueous solution is used at 50 ° C. for 30 seconds. After degreasing treatment, the aluminum surface is grained using ^three bundled nylon brushes having a bristle diameter of 0.3 mm and a pumice-water suspension having a median diameter of 25 μm (specific gravity: 1.1 g / cm ³ ) Washed well with. This plate was etched by being immersed in a 25 mass% sodium hydroxide aqueous solution at 45 ° C for 9 seconds, washed with water, further immersed in 20 mass% nitric acid 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 the nitric acid electrolysis was 175 C / dm ² when the aluminum plate was the anode. Then, water washing by spraying was performed.
Next, a 0.5% by mass hydrochloric acid aqueous solution (containing 0.5% by mass of aluminum ions) and an electrolytic solution having a liquid temperature of 50 ° C. and nitric acid electrolysis under the condition of an electric quantity of 50 C / dm ² when the aluminum plate is an anode. In the same manner as above, an electrochemical surface roughening treatment was performed, followed by washing with water by spraying. The plate was provided with a direct current anodic oxide coating of 2.5 g / m ² at a current density of 15 A / dm ² using 15% by weight sulfuric acid (containing 0.5% by weight of aluminum ions) as an electrolytic solution, and then washed and dried. Got the body. The center line average roughness (Ra) of the support was measured using a needle having a diameter of 2 μm and found to be 0.51 μm.

(2) Preparation of undercoat layer coating solution An undercoat layer coating solution (1) was prepared by mixing components having the following composition.
<Undercoat layer coating solution (1) composition>
・ Undercoat compound (1) 0.017g
・ Methanol 9.00g
・ Water 1.00g

(3) Synthesis of thermoplastic polymer fine particles 15 g of styrene and 200 ml of a polyoxyethylene nonylphenol aqueous solution (concentration: 9.84 × 10 ⁻³ mol ⁻¹ ) are added, and the system is replaced with nitrogen gas while stirring at 250 rpm. This solution is brought to 25 ° C., and 10 ml of an aqueous cerium (IV) ammonium salt solution (concentration: 0.984 × 10 ⁻³ mol ⁻¹ ) is added. At this time, an aqueous ammonium nitrate solution (concentration 58.8 × 10 ⁻³ mol ⁻¹ ) is added to adjust the pH to 1.3 to 1.4. This was then stirred for 8 hours. The solid content concentration of the liquid thus obtained was 9.0% by mass, and the average particle size measured by a particle size distribution measuring device “LA-910” manufactured by Horiba Seisakusho was 0.4 μm. It was. The synthesized fine particles had a glass transition temperature of 100 ° C. The glass transition temperature is an extrapolated glass transition start temperature determined by the method described in JIS K7121 using a heat flux type differential scanning calorimeter (DSC200, manufactured by SII Nano Technology).

(4) Synthesis of polymer fine particles having thermally reactive functional groups Allyl methacrylate 7.5 g, butyl methacrylate 7.5 g, and polyoxyethylene nonylphenol aqueous solution 200 ml (concentration 9.84 × 10 ⁻³ mol ⁻¹ ) were added at 250 rpm. While stirring, the inside of the system is replaced with nitrogen gas. This solution is brought to 25 ° C., and 10 ml of an aqueous cerium (IV) ammonium salt solution (concentration: 0.984 × 10 ⁻³ mol ⁻¹ ) is added. At this time, an aqueous ammonium nitrate solution (concentration 58.8 × 10 ⁻³ mol ⁻¹ ) is added to adjust the pH to 1.3 to 1.4. This was then stirred for 8 hours. The solid content concentration of the liquid thus obtained was 9.5% by mass, and the average particle size measured with a particle size distribution measuring device “LA-910” manufactured by Horiba Seisakusho was 0.4 μm. It was. The glass transition temperature obtained by the same method as described above was 60 ° C.

(5) Synthesis of Microcapsule (1) Containing Polymerizable Compound Trimethylolpropane and xylene diisocyanate adduct (manufactured by Mitsui Takeda Chemical Co., Ltd., Takenate D-110N, 75% by mass ethyl acetate solution) as an oil phase component ) 10 g, Aronix M-215 (manufactured by Toagosei Co., Ltd.), 6.00 g, and Pionein A-41C (manufactured by Takemoto Yushi Co., Ltd.) 0.18 g were dissolved in 16.61 g of ethyl acetate. As an aqueous phase component, 37.5 g of a 4 mass% aqueous solution of PVA-205 was prepared. The oil phase component and the aqueous phase component were mixed and emulsified for 10 minutes at 12000 rpm using a homogenizer. The obtained emulsion was added to 23 g of distilled water, stirred at room temperature for 30 minutes, and then stirred at 40 ° C. for 2 hours. The microcapsule solution thus obtained was diluted with distilled water so that the solid content concentration was 15% by mass. The particle size of the microcapsules obtained here was 0.2 μm as measured by a particle size distribution measuring device “LA-910” manufactured by Horiba, Ltd.
The glass transition temperature obtained by the same method as described above was 110 ° C.

(6) Preparation of Image Recording Layer Coating Liquid Image recording layer coating liquids (1) and (2) were prepared by dissolving or dispersing the components in a solvent according to the following coating liquid formulation. As the image recording layer coating liquid (3), an organic solvent liquid and an aqueous solvent liquid image recording layer coating liquid having the following compositions were prepared, respectively, and then the aqueous solvent liquid was added while stirring the organic solvent liquid. Stirring was stopped 15 minutes after the addition.

Image recording layer coating solution (1) [Image recording layer coating solution containing thermoplastic polymer fine particles]
-Synthesized thermoplastic polymer fine particles (9 mass% aqueous solution) 68.8g
・ Infrared absorber (1) 0.3g
・ Polyhydroxyethyl acrylate 0.5g
(Weight average molecular weight 25,000)
・ 3-methoxy-2-propanol 30.3g

Image recording layer coating solution (2) [Image recording layer coating solution containing polymer fine particles having a thermally reactive functional group]
-Synthesized polymer fine particles having thermally reactive functional groups (9.5% by mass aqueous solution) 54.8 g
・ Infrared absorber (1) 0.3g
-Polymerization initiator (1) 0.2g
・ Polymerizable compound Aronix M-215 (manufactured by Toagosei Co., Ltd.) 1.0 g
・ Polyhydroxyethyl acrylate (weight average molecular weight 25,000) 0.5g
1-methoxy-2-propanol 44.0 g

Image recording layer coating solution (3) [Image recording layer coating solution containing microcapsules containing a polymerizable compound]
<Organic solvent solution>
・ Infrared absorber (2) 0.2g
・ Polymerization initiator (1) 1.0 g
・ Binder polymer (1) (average molecular weight 80,000) 1.6 g
Polymerizable compound Aronix M-215 (manufactured by Toagosei Co., Ltd.) 3.9 g
・ Propylene glycol monomethyl ether 86.1g
・ Methyl ethyl ketone 11.0g

<Water solvent solution>
・ Microcapsules containing polymerizable compound (1) 26.5 g
・ Distilled water 47.1g
・ Fluorosurfactant (1) 0.05g

(7) Preparation of overcoat layer coating solution Overcoat layer coating solution 1 was prepared by mixing and dissolving components having the following composition.
<Overcoat layer coating solution 1>
・ PVA105 (Kuraray) 5.37g
・ Polyvinylpyrrolidone 0.05g
・ Emalex 710 (nonionic surfactant: manufactured by Kao) 0.43g
・ Somasif MEB-3L 15.00g
(Swellable mica aqueous dispersion: manufactured by Co-op Chemical)
・ Water 54.15g

(8) Coating and drying A lithographic printing plate using the production line shown in FIG. 1 under the coating conditions shown in Tables 1 to 3, coating of the image recording layer and overcoat layer, drying conditions, and manufacturing conditions listed in Table 4 An original plate was produced.

2. Evaluation of Production Method The obtained lithographic printing plate precursor was exposed with a Trend setter 3244VX manufactured by Creo equipped with a water-cooled 40 W infrared semiconductor laser under the conditions of an output of 9 W, an outer drum rotating speed of 210 rpm, and a resolution of 2400 dpi. The exposed exposed original plate was attached to a cylinder of a Sprint 25 printing machine manufactured by Komori Corporation without developing. After supplying fountain solution and ink using 4% by volume aqueous solution of fountain solution IF102 (Fuji Photo Film) and TRANS-G (N) black ink (manufactured by Dainippon Ink & Chemicals, Inc.), every hour Printing was performed at a printing speed of 8000 sheets, and the number of printed sheets required to obtain a good printed material was evaluated as on-press developability. The results are shown in Table 4.

  As is apparent from Table 4, the production method of the present invention suppresses the transfer of the image recording layer to the transport roll, thereby improving the yield and suppressing the deformation and destruction of the fine particles. High developability was obtained.

Example 7
A lithographic printing plate precursor was prepared and evaluated in the same manner as in Example 5 except that the following microgel (1) was used instead of the microcapsule (1) in Example 5.
There was a slight transfer of the image recording layer to the conveying roller 53, and the on-press developability was 40 sheets.

(Synthesis of microgel (1))
As an oil phase component, trimethylolpropane and xylene diisocyanate adduct (Mitsui Takeda Chemical Co., Ltd., Takenate D-110N) 10 g, pentaerythritol triacrylate (Nippon Kayaku Co., Ltd., SR444) 3.15 g and 0.1 g of Piionin A-41C (manufactured by Takemoto Yushi Co., Ltd.) was dissolved in 17 g of ethyl acetate. As an aqueous phase component, 40 g of a 4% by mass aqueous solution of PVA-205 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, stirred at room temperature for 30 minutes, and then stirred at 50 ° C. for 3 hours. The solid content concentration of the microgel solution thus obtained was diluted with distilled water so as to be 15% by mass. The average particle size was 0.2 μm. The glass transition temperature was 105 ° C.

Schematic diagram of the production line

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Production line 2 Undercoat layer coating apparatus 3 Image recording layer coating apparatus 4 Overcoat layer coating apparatus 5 Undercoat layer drying furnace 6 Image recording layer drying furnace 7 Overcoat layer drying furnace 8-15 Heating chambers 16-21 Openings 22-26 Partition walls 27 to 34 Rectifier plates 35 to 42 Air supply ports 43 to 50 Exhaust ports 51 to 57 Conveying rollers (coating surface contact)
58 Web winding device 59 Support web

Claims (5)

  A method for producing a lithographic printing plate precursor having an image recording layer containing at least resin fine particles on a support, wherein the production equipment and the support are brought into contact with the surface of the image recording layer. A method for producing a lithographic printing plate precursor, which is performed at a temperature equal to or lower than a transition temperature.   2. The method for producing a lithographic printing plate precursor as claimed in claim 1, wherein the resin fine particles are heat-reactive polymer fine particles.   2. The method for producing a lithographic printing plate precursor as claimed in claim 1, wherein the resin fine particles are microcapsules or microgels containing a compound having a thermally reactive group.   The lithographic printing plate according to any one of claims 1 to 3, wherein the image recording layer contains an infrared absorber and a polymerization initiator in addition to the resin fine particles, and is polymerized and cured by infrared laser irradiation. Production method of the original plate.   The method for producing a lithographic printing plate precursor as claimed in any one of claims 1 to 4, wherein the image recording layer is removable with printing ink and / or fountain solution.

Images