JP2005305741A - Lithographic printing plate material, lithographic printing plate and printing method using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lithographic printing plate material, the plate-making of which can be performed by a simple water developing treating operation or can be performed under being directly installed on a printing machine without necessitating developing treatment and which develops few coating trouble at the manufacture of a printing plate, and a printing method using it. <P>SOLUTION: In the lithographic printing plate material, which is formed by providing an undercoating layer, a hydrophilic layer and an image forming layer in the order named and is wound in a roll, after corona discharge treatment is applied to the surface of the undercoating layer by at least 3 W/m<SP>2</SP>min and below 40W/m<SP>2</SP>min, the hydrophilic layer is coated on the undercoating layer. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a lithographic printing plate material, and in particular, relates to a lithographic printing plate material (hereinafter also referred to as a printing plate material) that can be directly loaded into a printing press without requiring a simple water development process or a development process. .

  With the digitization of print data, there is a need for CTP (Computer-to-Plate) that is inexpensive, easy to handle, and has the same printability as the PS plate. In particular, in recent years, there is an increasing expectation for a so-called processless plate that does not require a development treatment with a special agent and can be applied to a printing press having a direct imaging (DI) function.

  As the structure of the processless plate, it is possible to use the same aluminum grain as the PS plate, but from the viewpoints of freedom of layer structure and cost reduction, various types of processes using coated and formed hydrophilic layers. Wrestles have been proposed. As such a processless, at present, it is substantially provided only for DI printing press applications (see, for example, Patent Document 1), and a processless plate having sufficient performance as a general-purpose printing plate material is provided. Absent.

  The so-called thermal type that forms an image by infrared laser exposure is mainly used for the processless plate, but the thermal type can be roughly divided into two types. One type of thermal type printing plate material is an ablation type. For example, two layers having different affinity for dampening water or ink used for printing are laminated on a substrate, and the surface side thereof is laminated. This layer is ablated by laser exposure and completely removed. However, such a type of printing plate material has a problem in that it is necessary to attach to the exposure apparatus a mechanism for completely sucking and removing the scattered matter on the ablated surface side layer. In addition, since the energy required for exposure is relatively high, it is necessary to reduce the beam linear velocity during exposure (for example, to reduce the rotation speed of the exposure drum), which may reduce image formation productivity.

  Another type of thermal type printing plate material is an on-press development type. In this type, for example, two layers having different affinity for dampening water or ink used for printing are laminated on a substrate, and the adhesive force between the surface side layer and the lower layer is changed by laser exposure, A portion having a weak adhesive force is removed on a printing press. Various parts such as contact with dampening water supply roller, dissolution and swelling by application of dampening water, contact with ink roller, peeling by ink tack, contact with blanket cylinder, etc. The method can be used.

  As an example of this type, there is disclosed a lithographic printing plate precursor that can form a high-sensitivity and high-resolution image without the need for development processing and without ablation, and has excellent scratch resistance and printing durability, and a printing method using the same. (See, for example, Patent Document 2).

From the viewpoint of printing material cost, a printing plate material using a plastic support wound in a roll shape as a product form is preferred. When a plastic support is used, it is preferable that the hydrophilic layer is formed by coating as printing plate performance, and an aqueous coating solution is more preferable in consideration of printing suitability. However, since it is difficult to directly apply a water-based hydrophilic layer to a plastic support, a method of applying and forming an undercoat layer on a plastic support and applying a hydrophilic layer thereon has been adopted. However, the types and amounts of organic substances that can be added to the hydrophilic layer are limited from the standpoint of printing stains, etc., and it is difficult to freely control the surface tension and viscosity of the hydrophilic layer coating solution. It was necessary to improve wettability.
Japanese Patent No. 2938397 Japanese Patent Laid-Open No. 2001-138852

  An object of the present invention is to make a plate by a simple water development processing operation, or to make a plate by directly loading it into a printing machine without the need for development processing, and a lithographic printing plate material with less coating failure during the production of the printing plate And a printing method using the planographic printing plate material.

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

(Claim 1)
In a lithographic printing plate material in which an undercoat layer, a hydrophilic layer, and an image forming layer are sequentially provided on a plastic support and wound in a roll, the surface of the undercoat layer is 3 W / m ² · min or more, 40 W / m A lithographic printing plate material comprising a hydrophilic layer after a corona discharge treatment of less than ² minutes.

(Claim 2)
2. The lithographic printing plate material according to claim 1, wherein the undercoat layer has a two-layer structure.

(Claim 3)
The lithographic printing plate material according to claim 1, wherein the hydrophilic layer is applied by a wire bar method.

(Claim 4)
The photothermal conversion agent for converting near infrared rays into heat is contained in at least one of the hydrophilic layer and the image forming layer provided in the rolled lithographic printing plate material. Planographic printing plate material.

(Claim 5)
The lithographic printing plate material according to any one of claims 1 to 4, wherein the hydrophilic layer is formed by a coating step and has a two-layer structure.

(Claim 6)
The lithographic printing plate material according to any one of claims 1 to 5, wherein a backcoat layer is provided on the back surface of the image forming layer side coating surface.

(Claim 7)
An image is formed on the lithographic printing plate material according to any one of claims 1 to 6 using a thermal head or a thermal laser.

(Claim 8)
A lithographic printing plate material according to any one of claims 1 to 6, wherein the lithographic printing plate material is laser-exposed based on image information, attached to a printing machine without being subjected to a wet development process, and printed on a printing paper.

  ADVANTAGE OF THE INVENTION According to this invention, the lithographic printing plate material which can be produced stably and gives the lithographic printing plate which has the outstanding printing performance can be provided.

  Hereinafter, the present invention will be described in detail.

(Support)
As a constituent material of the plastic film support according to the present invention, a plastic film is preferable. For example, polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polybutylene naphthalate (PBN) polyimide, polyamide, polycarbonate (PC), Shinji Examples include tactic polystyrene (sPS), polysulfone, polyphenylene oxide, and cellulose esters.

The support according to the present invention has an elastic modulus (E120) at 120 ° C. of 9.81 × 10 ^{2 to} 58.8 × 10 ² MPa from the viewpoint of imparting the above-mentioned handling suitability to the printing plate material of the present invention. It is preferable that it is 11.8 × 10 ^{2 to} 49.0 × 10 ² MPa. Specifically, PEN (E120 = 10.4 × 10 ² MPa), PET (E120 = 14.7 × 10 ² MPa), PBN (E120 = 15.7 × 10 ² MPa), PC (E120 = 16.7) × 10 ² MPa), sPS (E120 = 21.6 × 10 ² MPa), polyetherimide (E120 = 18.6 × 10 ² MPa), polyarylate (E120 = 16.7 × 10 ² MPa), polysulfone ( E120 = 17.7 × 10 ² MPa), polyethersulfone (E120 = 16.7 × 10 ² MPa) and the like. These may be used alone, or may be laminated or mixed. Among them, particularly preferred plastic films include PEN and PET.

  Here, the elastic modulus was obtained by using the tensile tester to determine the slope of the stress with respect to the strain amount in the region where the strain indicated by the standard line of the sample conforming to JIS C2318 and the corresponding stress show a linear relationship. Is. This is a value called Young's modulus, and in the present invention, this Young's modulus is defined as an elastic modulus.

  Furthermore, in order for the printing plate material to exhibit the effects described in the present invention, the support has an average film thickness in the range of 50 to 500 μm from the viewpoint of improving handling suitability when the printing plate material is installed in a printing machine. And the thickness distribution is preferably 10% or less.

  The average film thickness of the support is preferably in the range of 110 to 500 μm as described above, more preferably in the range of 120 to 400 μm, and particularly preferably in the range of 125 to 300 μm.

  The thickness distribution of the support (the difference between the maximum and minimum thickness values divided by the average thickness and expressed as a percentage) is preferably 10% or less as described above, more preferably 8% or less. Yes, particularly preferably 6% or less. Here, the method for measuring the thickness distribution of the support is as follows. The support cut out into a square having a side of 60 cm is drawn in a grid pattern at intervals of 10 cm vertically and horizontally, the thickness of these 36 points is measured, and the average value and maximum value are measured. Find the value and minimum value.

(Method for producing support)
In order to adjust the average film thickness and thickness distribution of the support to the above ranges, there are methods of adjusting the film forming conditions appropriately or adjusting with a smooth roller or the like while reheating after film formation. It is preferable to manufacture by the film forming process described in 1.

  As a film forming means for the support, the thermoplastic resin is melted between a melting point (Tm) and Tm + 50 ° C., filtered through a sintered filter, and then extruded from a T-die, and a glass transition temperature (Tg) −50 ° C. An unstretched sheet is formed on a casting drum whose temperature is adjusted to ~ Tg. At this time, in order to make the thickness distribution within the above range, it is preferable to use an electrostatic application method or the like.

  The unstretched sheet is longitudinally stretched 2 to 4 times between Tg and Tg + 50 ° C. Further, as another method for adjusting the thickness distribution to the above range, it is preferable to carry out multi-stage stretching in the longitudinal direction. At this time, it is preferable to adjust the temperature of the post-stage stretching to be higher in the range of 1 to 30 ° C than that of the pre-stage stretching, and it is more preferable to perform the stretching while adjusting the temperature to be higher in the range of 2 to 15 ° C.

  The magnification of the former drawing is preferably 0.25 to 0.7 times, more preferably 0.3 to 0.5 times the magnification of the latter drawing. Thereafter, the film is held in the temperature range of Tg-30 ° C to Tg for 5 to 60 seconds, more preferably 10 to 40 seconds, and then stretched 2.5 to 5 times between Tg and Tg + 50 ° C in the transverse direction. preferable.

  Thereafter, heat fixation is performed in a state of being gripped with a chuck at (Tm-50 ° C) to (Tm-5 ° C) for 5 to 120 seconds. At this time, it is also preferable to narrow the chuck interval by 0 to 10% in the width direction (thermal relaxation). After cooling this, a method such as obtaining a multiaxially stretched film after winding a knurling of 10 to 100 μm at the end (also referred to as providing a knurling height) is preferable.

(Fine particles)
It is preferable to add 1 to 1000 ppm of 0.01 to 10 μm fine particles in the above support for improving handling properties.

  Here, the fine particles may be either organic or inorganic. Examples of inorganic substances include silica described in Swiss Patent 330,158, glass powder described in French Patent 1,296,995, and alkaline earth metal described in British Patent 1,173,181. Alternatively, carbonates such as cadmium and zinc can be used. Examples of organic substances include starch described in U.S. Pat. No. 2,322,037, starch derivatives described in Belgian Patent 625,451 and British Patent 981,198, and polyvinyls described in Japanese Patent Publication No. 44-3643. Such as alcohol, polystyrene or polymethacrylate described in Swiss Patent 330,158, polyacrylonitrile described in US Pat. No. 3,079,257, and polycarbonate described in US Pat. No. 3,022,169 Organic fine particles can be used. The shape of the fine particles may be either regular or irregular.

(Polyvinylidene chloride resin)
In the printing plate material of the present invention, it is preferable that the support is the above-mentioned plastic film, and one surface of the support having the image forming functional layer has at least one layer containing a polyvinylidene chloride resin. .

  As the polyvinylidene chloride resin, a copolymer is preferably used, and the amount of the polymerization component of the vinylidene chloride monomer in the repeating unit of the copolymer is preferably 70 to 99.9% by mass, more preferably It is 85-99 mass%, Most preferably, it is 90-99 mass%.

  Examples of copolymer components other than the vinylidene chloride monomer in the copolymer include methacrylic acid, acrylic acid, itaconic acid, citraconic acid and esters thereof, acrylonitrile, methacrylonitrile, methyl acrylate, ethyl acrylate, methyl methacrylate, Examples thereof include glycidyl methacrylate, 2-hydroxyethyl methacrylate, vinyl acetate, acrylamide, and styrene.

  The weight average molecular weight of these copolymers is preferably in the range of 5000 to 100,000, more preferably 8000 to 80,000, and particularly preferably in the range of 10,000 to 45,000. Here, the weight average molecular weight can be measured by a commercially available GPC (gel permeation chromatography) apparatus.

  The arrangement of the monomer units of these copolymers is not limited, and any of random, block and the like may be used.

  When the polyvinylidene chloride resin is an aqueous dispersion, it may be a latex of polymer particles having a uniform structure or a latex of so-called core / shell structure polymer particles having different compositions in the core part and the shell part. Specific examples of the vinylidene chloride copolymer include the following. However, the numerical value indicating the copolymerization ratio is a mass ratio, and Mw represents a weight average molecular weight.

(A) Latex of vinylidene chloride / methyl acrylate / acrylic acid (90/9/1) (Mw = 42000)
(B) Latex (Mw = 40000) of vinylidene chloride / methyl acrylate / methyl methacrylate / acrylonitrile / methacrylic acid (87/4/4/4/1)
(C) Latex (Mw = 38000) of vinylidene chloride / methyl methacrylate / glycidyl methacrylate / methacrylic acid (90/6/2/2)
(D) Latex (Mw = 44000) of vinylidene chloride / ethyl methacrylate / 2-hydroxyethyl methacrylate / acrylic acid (90/8 / 1.5 / 0.5)
(E) Core / shell type latex (90 mass% core portion, 10 mass% shell portion)
Core part: vinylidene chloride / methyl acrylate / methyl methacrylate / acrylonitrile / acrylic acid (93/3/3 / 0.9 / 0.1)
Shell part: vinylidene chloride / methyl acrylate / methyl methacrylate / acrylonitrile / acrylic acid (88/3/3/3/3) (Mw = 38000)
(F) Core / shell type latex (core part 70% by mass, shell part 30% by mass)
Core part: vinylidene chloride / methyl acrylate / methyl methacrylate / acrylonitrile / methacrylic acid (92.5 / 3/3/1 / 0.5)
Shell part: vinylidene chloride / methyl acrylate / methyl methacrylate / acrylonitrile / methacrylic acid (90/3/3/1/3) (Mw = 20000)
(Polyvinylidene chloride resin-containing layer)
The polyvinylidene chloride resin according to the present invention is an undercoat layer, a hydrophilic layer described later, an image forming functional layer, other layers, etc., as long as the image forming functional layer is coated on the support. Although it may be contained in this layer, it is preferably contained in the undercoat layer. The undercoat layer may be a single layer or a plurality of layers. The thickness of these layers is preferably provided at a thickness of 0.5 to 10 μm on at least one side of the support, and more preferably, a layer having a thickness of 0.8 to 5 μm is provided on both sides of the support. Particularly preferably, the thickness is 1.0 to 3 μm on both sides.

(Moisture content of support)
The water content of the support in the present invention is D (mass%) represented by the following formula.

D ′ = (w ′ / W ′) × 100
In the formula, W ′ is the mass of the support in a humidity control equilibrium under an atmosphere of 25 ° C. and 60% RH (relative humidity), and w ′ is the support in a humidity control equilibrium under an atmosphere of 25 ° C. and 60% RH. Represents the water content of the body.
The moisture content of the support is preferably 0.01 to 0.5% by mass or less, and more preferably 0.01 to 0.3% by mass.

  Means for controlling the moisture content of the support to 0.5% by mass or less are as follows: (1) The support is heat-treated at 100 ° C. or higher immediately before the application liquid for the image forming functional layer and other layers is applied (2 ) Control the relative humidity in the step of applying the coating liquid for the image forming functional layer and other layers. (3) Heat the support at 100 ° C. or higher before applying the coating liquid for the image forming functional layer and other layers. And covering with a moisture-proof sheet, storing, and applying immediately after opening. Two or more of these may be combined.

(Undercoat coating on support)
The support according to the present invention performs undercoat layer coating on the coated surface in order to improve adhesion with the coated layer. As the undercoat layer, a layer containing gelatin or latex is preferably provided on the support. Further, the conductive polymer-containing layer described in paragraphs “0031” to “0073” of JP-A-7-20596 and the metal oxide-containing layer described in paragraphs “0074” to “0081” of JP-A-7-20596 It is preferable to provide such a conductive layer. The conductive layer may be coated on any side as long as it is on the plastic film support, but it is preferably coated on the opposite side of the image forming functional layer with respect to the support. When this conductive layer is provided, the chargeability is improved, the adhesion of dust and the like is reduced, and white-out failures during printing are greatly reduced.

  In addition, a plastic film is used as a support according to the present invention, and a plastic film and a metal plate (iron, stainless steel, aluminum, etc.) or a material such as paper coated with polyethylene (also referred to as a composite substrate) are appropriately bonded together. A composite support can also be used. These composite base materials may be bonded together before forming the coating layer, may be bonded after forming the coating layer, or may be bonded immediately before being attached to the printing press.

(Corona discharge)
In order to exert the effect of the present invention, it is necessary to perform corona discharge after applying the undercoat layer. The corona discharge treatment can be performed by the method described in JP-B-39-12838, JP-A-47-19824, and JP-A-48-28067. In the present invention, the discharge intensity is 3 W / m ² · min or more, 40 W / It must be less than m ² · min, preferably 5 W / m ² · min or more and less than 35 W / m ² · min, more preferably 8 W / m ² · min or more and less than 25 W / m ² · min . When the corona discharge intensity is less than 3 W / m ² · min, a coating failure occurs in the hydrophilic layer coating, and the on-press developability of the failed portion is lowered. On the other hand, if it exceeds 40 W / m ² · min, the film strength of the undercoat layer deteriorates and the adhesiveness with the hydrophilic layer decreases, so that the printing durability as a printing plate decreases.

(Stiffness)
Since the printing plate material of the present invention is constituted by a plastic support, it preferably has a stiffness of 50 to 500 g. If it is less than 50 g, the printing plate material is not elastic, and if it exceeds 500 g, the printing plate material is too strong, and in any case, it is difficult to handle the printing plate material and attach the printing plate to the plate cylinder.

  Stiffness can be measured using a commercially available film stiffness tester (for example, Stiffness Tester UT-100-230 or Stiffness Tester UT-200GR manufactured by Toyo Seiki Seisakusho Co., Ltd.). Specifically, both ends on the long side of a 20 cm × 10 cm sample placed on a flat table are brought close to the table, each end of 5 cm is fixed to the table, and the central part is bent upward by 1 cm from the table, Evaluation is based on the load when the top is pushed down by 3 mm with a needle.

(Hydrophilic layer)
Examples of the material used for the hydrophilic layer of the printing plate material of the present invention include the following.

  The material forming the hydrophilic matrix is preferably a metal oxide, more preferably metal oxide fine particles. Examples include colloidal silica, alumina sol, titania sol, and other metal oxide sols. The metal oxide may be spherical, feathered, or any other shape, and the average particle size is 3 to 100 nm. Several kinds of metal oxide fine particles having different average particle diameters can be used in combination. Further, surface treatment may be performed on the particle surface.

  The metal oxide particles can be used as a binder by utilizing the film forming property. The decrease in hydrophilicity is less than when an organic binder is used, and it is suitable for use in a hydrophilic layer. Of these, colloidal silica is particularly preferred. Colloidal silica has the advantage of high film-forming properties even under relatively low temperature drying conditions, and can provide good strength.

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

  Necklace-shaped colloidal silica used in the present invention is a general term for the water dispersion diameter of spherical silica whose primary particle diameter is on the order of nm. Specifically, spherical colloidal silica having a primary particle diameter of 10 to 50 nm is 50 to 50 nm. It means “pearl necklace-like” colloidal silica bonded to a length of 400 nm. The pearl necklace shape (that is, a pearl necklace shape) means that an image in a state in which the silica particles of colloidal silica are connected and joined has a shape like a pearl necklace.

  The bond between the silica particles constituting the necklace-shaped colloidal silica is presumed to be —Si—O—Si— in which —SiOH groups present on the surface of the silica particles are dehydrated. Specific examples of the necklace-shaped colloidal silica include “Snowtex-PS” series manufactured by Nissan Chemical Industries, Ltd.

  As product names, Snowtex-PS-S (average particle size in a connected state is about 110 nm), -PS-M (average particle system in a connected state is about 120 nm) and -PS-L (connected) The average particle diameter in the state is about 170 nm), and the acidic products corresponding to these are SNOWTEX-PS-S-O, -PS-MO, and -PS-LO, respectively.

  By adding necklace-like colloidal silica, it becomes possible to maintain the strength while ensuring the porosity of the layer, and it can be preferably used as a porous material for the hydrophilic layer matrix. Among these, when using SNOWTEX-PS-S, -PS-M and -PS-L which are alkaline, the strength of the hydrophilic layer is improved, and even when the number of printed sheets is large, scumming is generated. Particularly preferred.

  Colloidal silica is known to have a stronger bonding force as the particle system is smaller. In the present invention, colloidal silica having an average particle diameter of 20 nm or less is preferably used, and more preferably 3 to 15 nm. Moreover, among the colloidal silicas, as described above, it is particularly preferable to use alkaline colloidal silica because alkaline ones have a high effect of suppressing the occurrence of soiling. Alkaline colloidal silica having an average particle size within this range is manufactured by Nissan Chemical Co., Ltd .: Snowtex-20 (particle diameter 10-20 nm), -30 (particle system 10-20 nm), -40 (particle diameter 10 20 nm), -N (particle diameter of 10 to 20 nm), -S (particle diameter of 8 to 11 nm), and -XS (particle diameter of 4 to 6 nm).

  Colloidal silica having an average particle size of 20 nm or less is particularly preferable because it can be further improved in strength while maintaining the porous property of the layer when used in combination with the aforementioned necklace-shaped colloidal silica. The ratio of colloidal silica / necklace-shaped colloidal silica having an average particle size of 20 nm or less is preferably 95/5 to 5/95, more preferably 70/30 to 20/80, and more preferably 60/40 to 30/70. Further preferred.

  As a porous material for the hydrophilic layer matrix, porous metal oxide particles having a particle size of less than 1 μm can be contained. As the porous metal oxide particles, porous silica, porous aluminosilicate particles, or zeolite particles described later can be preferably used. The porous silica particles are generally produced by a wet method or a dry method. In the wet method, the gel obtained by neutralizing the silicate aqueous solution is dried and pulverized, or the neutralized precipitate is pulverized. In the dry method, silicon tetrachloride is burned together with hydrogen and oxygen to obtain silica.

  These particles can be controlled in porosity and particle size by adjusting production conditions. As the porous silica particles, those obtained from a wet gel are particularly preferable. The porous aluminosilicate particles are produced, for example, by the method described in JP-A-10-71764. That is, it is an amorphous composite particle synthesized by hydrolysis using aluminum alkoxide and silicon alkoxide as main components. The ratio of alumina to silica in the particles can be synthesized in the range of 1: 4 to 4: 1 (molar ratio). Moreover, what was manufactured as a composite particle more than 3 component type | system | group by adding another metal alkoxide at the time of manufacture can also be used. These composite particles can also control the porosity and particle size by adjusting the production conditions.

  The porosity of the particles is preferably 0.5 ml / g or more in terms of pore volume, more preferably 0.8 ml / g or more, and still more preferably in the range of 1.0 to 2.5 ml / g.

  The pore volume is closely related to the water retention of the coating film. The larger the pore volume, the better the water retention and the less difficult it is to stain during printing, and the greater the water volume latitude, but greater than 2.5 ml / g. Then, the particles themselves become very brittle, and the durability of the coating film is lowered. On the other hand, when the pore volume is less than 0.5 ml / g, the printing performance may be slightly insufficient.

  Zeolite can also be used as the porous material of the present invention. Zeolite is a crystalline aluminosilicate and is a porous body having regular three-dimensional network voids having a pore diameter of 0.3 to 1 nm. The general formula combining natural and synthetic zeolite is expressed as follows:

(M ₁ , M ₂ ^1/2 ) _m (Al _m Si _n O ₂ (m + n)) · xH ₂ O
Here, M _1, M ₂ are each exchangeable cations, M ₁ is ^{Li +, Na +, K +} , Tl +, Me 4 N + (TMA), Et 4 N + (TEA), Pr 4 N ⁺ (TPA), C ₇ H ₁₅ N ²⁺ , C ₈ H ₁₆ N ^{+ and the} like, and M ₂ is Ca ²⁺ , Mg ²⁺ , Ba ²⁺ , Sr ²⁺ , C ₈ H ₁₈ N ₂ ^2+. Etc. Me represents a methyl group, Et represents an ethyl group, and Pr represents a propyl group.

  Further, n ≧ m, and the value of m / n, that is, the Al / Si ratio is 1 or less. The higher the Al / Si ratio, the greater the amount of exchangeable cations, and thus the higher the polarity and therefore the higher the hydrophilicity. A preferable Al / Si ratio is 0.4 to 1.0, and more preferably 0.8 to 1.0. x represents an integer.

The zeolite particles used in the present invention are preferably synthetic zeolites having a stable Al / Si ratio and a relatively sharp particle size distribution. For example, zeolite A: Na ₁₂ (Al ₁₂ Si ₁₂ O ₄₈ ) 27H ₂ O; Al / Si ratio 1.0, zeolite X: Na ₈₆ (Al ₈₆ Si ₁₀₆ O ₃₈₄ ) • 264H ₂ O; Al / Si ratio 0.811, zeolite Y: Na ₅₆ (Al ₅₆ Si ₁₃₆ O ₃₈₄ ) · 250H ₂ O; Al / Si ratio 0.412 and the like. By containing highly hydrophilic porous particles having an Al / Si ratio of 0.4 to 1.0, the hydrophilicity of the hydrophilic layer itself is greatly improved, it is difficult to stain during printing, and the water latitude is widened. In addition, the dirt on the fingerprint marks is greatly improved. When the Al / Si ratio is less than 0.4, the hydrophilicity is insufficient, and the effect of improving the performance becomes small.

  The hydrophilic layer matrix of the printing plate material of the present invention can contain layered clay mineral particles. The layered mineral particles include kaolinite, halloysite, talc, smectite (montmorillonite, beidellite, hectorite, sabonite, etc.), clay minerals such as vermiculite, mica (mica), chlorite and hydrotalcite, layered polysilicate (kanemite). , Macatite, ialite, magadiite, kenyaite, etc.). Among them, it is considered that the higher the charge density of the unit layer (unit layer), the higher the polarity and the higher the hydrophilicity. The charge density is preferably 0.25 or more, more preferably 0.6 or more. Examples of the layered mineral having such a charge density include smectite (charge density 0.25 to 0.6; negative charge), vermiculite (charge density 0.6 to 0.9; negative charge) and the like. In particular, synthetic fluorine mica is preferable because it can be obtained with stable quality such as particle size. Of the synthetic fluorine mica, those that are swellable are preferred, and those that are free-swelled are more preferred.

  Also used are intercalation compounds of the above-mentioned layered minerals (pillar crystals, etc.), those subjected to ion exchange treatment, and those subjected to surface treatment (silane coupling treatment, compounding treatment with organic binder, etc.) can do.

  As the size of the flat lamellar mineral particles, the average particle diameter (maximum length of the particles) is less than 1 μm in the state of being contained in the layer (including the case where the swelling process and the dispersion peeling process have been performed). The aspect ratio is preferably 50 or more. When the particle size is in the above range, the continuity and flexibility in the planar direction, which are the characteristics of the thin layered particles, are imparted to the coating film, and it is difficult to crack and it can be made a tough coating film in a dry state. Moreover, in the coating liquid containing many particulate matters, sedimentation of particulate matter can be suppressed by the thickening effect of the layered clay mineral. When the particle diameter is larger than the above range, the coating film may be non-uniform, and the strength may be locally reduced. On the other hand, when the aspect ratio is not more than the above range, the number of tabular grains with respect to the addition amount is reduced, the viscosity is insufficient, and the effect of suppressing sedimentation of the particulate matter is reduced.

  The content of the layered mineral particles is preferably 0.1 to 30% by mass, and more preferably 1 to 10% by mass based on the entire layer. In particular, swellable synthetic fluorinated mica and smectite are preferable since they can be effective even when added in a small amount. The layered mineral particles may be added as a powder to the coating solution, but in order to obtain a good degree of dispersion even with a simple preparation method (no need for a dispersion step such as media dispersion), the layered mineral particles are used alone. It is preferable that the gel swollen in water is prepared and then added to the coating solution.

A silicate aqueous solution can also be used as another additive material in the hydrophilic layer matrix. Alkali metal silicates such as sodium silicate, potassium silicate, and lithium silicate are preferred, and the SiO ₂ / M ₂ O ratio is selected so that the pH of the entire coating solution when the silicate is added does not exceed 13. It is preferable for preventing dissolution of inorganic particles.

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

  Moreover, you may contain water-soluble resin. Examples of water-soluble resins include polysaccharides, polyethylene oxide, polypropylene oxide, polyvinyl alcohol, polyethylene glycol (PEG), polyvinyl ether, styrene-butadiene copolymer, conjugated diene polymer latex of methyl methacrylate-butadiene copolymer, acrylic Examples thereof include resins such as polymer polymer latex, vinyl polymer latex, polyacrylamide, and polyvinylpyrrolidone, and the water-soluble resin used in the present invention is preferably a polysaccharide.

  As the polysaccharide, starch, cellulose, polyuronic acid, pullulan, and the like can be used, but cellulose derivatives such as methyl cellulose salt, carboxymethyl cellulose salt, hydroxyethyl cellulose salt are particularly preferable, and sodium salt and ammonium salt of carboxymethyl cellulose are preferable. More preferred. This is because an effect of forming the surface shape of the hydrophilic layer in a preferable state can be obtained by including the polysaccharide in the hydrophilic layer.

  The surface of the hydrophilic layer preferably has a concavo-convex structure with a pitch of 0.1 to 20 μm like the aluminum grain of the PS plate, and this concavo-convex improves water retention and image area retention.

  Such a concavo-convex structure can be formed by adding an appropriate amount of a filler having an appropriate particle size to the hydrophilic layer matrix. However, the above-mentioned alkaline colloidal silica and the above-mentioned water-soluble solution are added to the hydrophilic layer coating solution. In order to obtain a structure having better printability, it is preferable to include a hydrophilic polysaccharide and form a phase separation when the hydrophilic layer is applied and dried.

  The shape of the concavo-convex structure (pitch, surface roughness, etc.) is determined depending on the type and addition amount of alkaline colloidal silica, the type and addition amount of water-soluble polysaccharides, the type and addition amount of other additives, the solid content concentration of the coating liquid, and the wetness. It is possible to appropriately control the film thickness, drying conditions, and the like.

  The water-soluble resin added to the hydrophilic matrix in the present invention is preferably present in a state where at least a part thereof is water-soluble and can be eluted in water. This is because even if it is a water-soluble material, when it is cross-linked by a cross-linking agent or the like and becomes insoluble in water, its hydrophilicity is lowered and printability may be deteriorated.

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

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

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

  Moreover, the photothermal conversion raw material mentioned later can also be contained. As the photothermal conversion material, in the case of a particulate material, the particle size is preferably less than 1 μm. In this invention, it is preferable to contain the particle | grains coat | covered with the inorganic particle or inorganic material whose particle size is 1 micrometer or more.

Porous, non-porous, organic resin particles, and inorganic fine particles may be used. As inorganic fillers, silica, alumina, zirconia, titania, carbon black, graphite, TiO ₂ , BaSO ₄ , ZnS, MgCO ₃ , CaCO _{3, ZnO, CaO, WS 2} , MoS 2, MgO, SnO 2, Al 2 O 3, α-Fe 2 O 3, α-FeOOH, SiC, CeO 2, BN, SiN, MoC, BC, WC, titanium carbide Corundum, artificial diamond, stone meteorite, garnet, silica, triboli, diatomaceous earth, dolomite, etc., organic fillers include polyethylene fine particles, fluorine resin particles, guanamine resin particles, acrylic resin particles, silicon resin particles, melamine resin particles, etc. I can do it. Examples of the inorganic filler include particles obtained by coating a core of organic particles such as polymethyl methacrylate (PMMA), polystyrene, and melamine with inorganic particles that are smaller in relay than the core particles. The particle size of the inorganic particles is preferably about 1/10 to 1/100 of the core particles. In addition, as the inorganic particles, known metal oxide particles such as silica, alumina, titania, zirconia and the like can be used. Various known methods can be used as the coating method, but the core material particles and the coating material particles collide with each other at high speed in the air like a hybridizer to fix the coating material particles by biting into the surface of the core material particles. A dry coating method for coating can be preferably used.

  Also, particles obtained by metal plating a core material of organic particles can be used. Examples of such particles include “Micropearl AU” manufactured by Sekisui Chemical Co., Ltd. in which resin particles are plated with gold.

  In particular, in order to suppress sedimentation in the coating solution, it is preferable to use porous inorganic fillers such as porous silica particles and porous aluminosilicate particles, and porous inorganic clothing fillers.

  The filler particle size is preferably 1 to 12 μm, more preferably 1.5 to 8 μm, and still more preferably 2 to 6 μm. When the particle diameter exceeds 12 μm, there is a concern that the resolution of image formation is reduced and the blanket stain is deteriorated. The addition amount of particles having a particle diameter of 1 μm or more is preferably 1 to 50% by mass, more preferably 5 to 40% by mass based on the entire hydrophilic layer.

  The hydrophilic layer as a whole preferably has a low content ratio of carbon-containing materials such as organic resin and carbon black in order to improve hydrophilicity, and the total of these materials is less than 9% by mass. Preferably, it is less than 5% by mass.

  As a form of this invention, you may provide a lower layer in a hydrophilic layer. When a lower layer is provided, the same material as the hydrophilic layer can be used as the material used for the lower layer. However, the lower layer has less advantage of being porous, and the nonporous material improves the coating strength, so the content of the porous material of the hydrophilic matrix is higher than that of the hydrophilic layer. Is preferably less, more preferably not contained.

  The amount of particles having a particle size of 1 μm or more is preferably 1 to 50% by mass, more preferably 5 to 40% by mass based on the entire lower layer.

  Also for the entire lower layer, like the hydrophilic layer, it is preferable that the content ratio of materials containing carbon such as organic resin and carbon black is low in order to improve hydrophilicity, and the total of these materials is less than 9% by mass. It is preferable that it is less than 5% by mass.

(Image forming layer)
The image forming layer containing the heat-fusible and / or heat-fusible fine particles can contain the following materials.

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

  Usable materials include paraffin, polyolefin, polyethylene wax, microcrystalline wax, fatty acid wax and the like. These have a weight average molecular weight (Mw) of about 800 to 10,000. In order to facilitate emulsification, these waxes can be oxidized to introduce polar groups such as hydroxyl groups, ester groups, carboxyl groups, aldehyde groups, and peroxide groups. Furthermore, in order to lower the softening point or improve the workability, these waxes are mixed with stearamide, linolenamide, laurylamide, myristamide, hardened bovine fatty acid amide, palmitoamide, oleic acid amide, rice sugar fatty acid amide, It is also possible to add coconut fatty acid amides or methylolated products of these fatty acid amides, methylene bisstellaramide, ethylene bisstellaramide and the like. Coumarone-indene resin, rosin-modified phenol resin, terpene-modified phenol resin, xylene resin, ketone resin, acrylic resin, ionomer, and copolymers of these resins can also be used. Among these, it is preferable to contain any of polyethylene, microcrystalline, fatty acid ester, fatty acid amide, and fatty acid. Since these materials have a relatively low melting point and a low melt viscosity, high-sensitivity image formation can be performed. Further, since these materials have lubricity, damage when a shearing force is applied to the surface of the printing plate material is reduced, and resistance to printing stains due to scratches and the like is improved.

  The heat-meltable fine particles are preferably dispersible in water, and the average particle size is preferably 0.01 to 10 μm, more preferably 0.1 to 3 μm. When the average particle size is smaller than 0.1 μm, when the coating solution for the layer containing the heat-meltable fine particles is applied onto the porous hydrophilic layer described later, the heat-meltable fine particles are not removed from the pores of the hydrophilic layer. It becomes easy to enter inside or into the gaps between fine irregularities on the surface of the hydrophilic layer, resulting in insufficient on-press development and concern about background staining. When the average particle size of the heat-meltable fine particles is larger than 10 μm, the resolution is lowered.

  The heat-meltable fine particles may be continuously changed in composition between the inside and the surface layer, or may be coated with different materials. As a coating method, a known microcapsule formation method, a sol-gel method, or the like can be used.

  The content of the heat-meltable fine particles in the image forming layer is preferably from 1 to 90% by mass, and more preferably from 5 to 80% by mass, based on the entire layer.

  Examples of the heat-fusible fine particles include thermoplastic hydrophobic polymer fine particles, and there is no specific upper limit for the softening temperature of the thermoplastic hydrophobic polymer fine particles. It is preferable that the temperature is lower than the decomposition temperature. The Mw of the high molecular polymer is preferably in the range of 10,000 to 1,000,000.

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

  The polymer polymer fine particles may be composed of a polymer polymer polymerized by any known method such as an emulsion polymerization method, a suspension polymerization method, a solution polymerization method, and a gas phase polymerization method. As a method of microparticulating a polymer polymer polymerized by a solution polymerization method or a gas phase polymerization method, a method of spraying a solution in an organic solvent of the polymer polymer into an inert gas and drying to form particles, Examples thereof include a method in which a high molecular weight polymer is dissolved in a water-immiscible organic solvent, this solution is dispersed in water or an aqueous medium, and the organic solvent is distilled off to form fine particles. In any of the methods, a surfactant, such as sodium lauryl sulfate, sodium dodecylbenzenesulfonate, polyethylene glycol, or a water-soluble resin, such as polyvinyl alcohol, is used as a dispersant or stabilizer in polymerization or micronization as necessary. May be used.

  The thermoplastic fine particles are preferably dispersible in water, and the average particle diameter is preferably 0.01 to 10 μm, more preferably 0.1 to 3 μm. When the average particle size is smaller than 0.01 μm, when the coating liquid for the layer containing the heat-meltable fine particles is applied onto the porous hydrophilic layer described later, the heat-meltable fine particles are not removed from the pores of the hydrophilic layer. It becomes easy to enter inside or into the gaps between fine irregularities on the surface of the hydrophilic layer, resulting in insufficient on-press development and concern about background staining. On the other hand, when the average particle size is larger than 10 μm, the resolution decreases.

  The thermoplastic fine particles may be continuously changed in composition between the inside and the surface layer, or may be coated with different materials. As a coating method, a known microcapsule formation method, a sol-gel method, or the like can be used.

As content of the thermoplastic fine particle in a layer, 1-90 mass% of the whole layer is preferable, and 5-80 mass% is still more preferable.

  The image forming layer containing the heat-fusible and / or heat-fusible fine particles can further contain a water-soluble material. By including the water-soluble material, when the image forming layer in the unexposed area is removed using dampening water or ink on the printing press, the removability can be improved.

  As the water-soluble material, the water-soluble resins mentioned as materials that can be contained in the hydrophilic layer can also be used. However, it is preferable to use saccharides in the image forming layer of the present invention, and it is particularly preferable to use oligosaccharides. preferable.

  Since the oligosaccharide dissolves quickly in water, the image forming functional layer in the unexposed area on the printing device can be removed very quickly, and the normal PS plate printing operation can be performed without being aware of the special removal operation. It can be removed by printing in the same manner as in the above, and there is no increase in printing waste paper. In addition, the oligosaccharide can maintain good printability of the hydrophilic layer without concern for lowering the hydrophilicity of the hydrophilic layer.

  An oligosaccharide is a crystalline substance that is soluble in water and generally sweet, and is obtained by dehydrating and condensing several monosaccharides by glycosidic bonds. Oligosaccharide is a kind of O-glycoside with sugar as aglycone, so it is easily hydrolyzed with acid to produce monosaccharide, and disaccharide, trisaccharide, tetrasaccharide, pentasaccharide, etc. depending on the number of molecules of monosaccharide produced are categorized. The oligosaccharide in the present invention refers to those from disaccharide to decasaccharide. These oligosaccharides are roughly classified into reducing oligosaccharides and non-reducing oligosaccharides depending on the presence or absence of a reducing group, homooligosaccharides composed of a single monosaccharide, and two or more types of monosaccharides. It is also classified as a hetero-oligosaccharide composed of

  Oligosaccharides exist naturally as free or glycosides and can also be obtained by partial hydrolysis of polysaccharides with acids or enzymes. In addition, various oligosaccharides are produced by enzymatic glycosyl transfer. Oligosaccharides are often present as hydrates in a normal atmosphere. Moreover, the melting point differs between hydrate and anhydride.

  In the present invention, it is preferable to coat and form a saccharide-containing layer with an aqueous solution. When formed from an aqueous solution, when the oligosaccharide present in the layer is an oligosaccharide that forms a hydrate, The melting point is considered to be that of the hydrate. Thus, since it has a relatively low melting point, the oligosaccharide also melts in the temperature range in which the hot melt fine particles melt or in the temperature range in which the hot melt fine particles fuse, and the porous hydrophilic layer of the hot melt fine particles It does not hinder image formation such as melt penetration into the film and fusion of heat-fused fine particles.

  Among oligosaccharides, trehalose is relatively inexpensive and can be obtained industrially at low cost, and despite its high solubility in water, its hygroscopicity is very low, and on-press developability and The storage stability is very good. In addition, when oligosaccharide hydrate is melted by heat to remove hydrated water and then solidified (within a short period of time after solidification), it becomes an anhydrous crystal, but trehalose has a melting point of anhydride rather than hydrate. Is characteristically higher than 100 ° C. This means that the exposed portion is melted by infrared exposure and immediately after re-solidification, the exposed portion is in a state of being difficult to melt at a high melting point, and is effective in causing image defects during exposure such as banding. In order to achieve the object of the present invention, trehalose is particularly preferable among oligosaccharides.

  The oligosaccharide content in the image forming layer is preferably 1 to 90% by mass, and more preferably 10 to 80% by mass of the entire layer.

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

  As a device suitable for scanning exposure, any type of device may be used as long as it can form an image on the surface of the printing plate material in accordance with an image signal from a computer using a semiconductor laser. Generally, the following three methods can be mentioned.

  (1) A method of exposing the entire surface of the printing plate material by performing two-dimensional scanning using one or a plurality of laser beams on the printing plate material held by the flat plate holding mechanism, and (2) a fixed cylinder The printing plate material held inside the cylindrical holding mechanism is scanned along the circumferential direction of the cylinder (main scanning direction) using one or more laser beams from the inside of the cylinder. A method in which the entire surface of the printing plate material is exposed by moving in a direction perpendicular to the direction (sub-scanning direction), and (3) a printing plate material held on the surface of a cylindrical drum that rotates about an axis as a rotating body, The entire printing plate material is exposed by moving in the direction perpendicular to the circumferential direction (sub-scanning direction) while scanning in the circumferential direction (main scanning direction) by rotating the drum using one or multiple laser beams from the outside. To do.

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

  In the printing plate material of the present invention, an image can be formed by directly applying an oleophilic material to the surface of the hydrophilic layer in an image-like manner. As one of methods for imparting an oleophilic material to the image, a method using a known thermal transfer method can be mentioned. Specifically, a method of transferring a heat-meltable ink from the ink ribbon having a heat-meltable ink layer to the surface of the hydrophilic layer in an image-like manner using a thermal head using a thermal transfer type printer can be mentioned.

  Also, using a digital proof device of an infrared laser heat-melt transfer method, a printing plate material is wound on an exposure drum with a hydrophilic layer on the outside, and an ink sheet further having a heat-meltable ink layer thereon is used as an ink. There can also be mentioned a method in which the surface is wound in contact with the hydrophilic layer, imagewise exposure is performed with an infrared laser, and the heat-meltable ink is imagewise transferred onto the surface of the hydrophilic layer. In this case, the photothermal conversion material may be contained in the hydrophilic layer, the ink sheet side may be contained in any layer, or both may be contained together.

  After forming an image with a heat-meltable ink on the hydrophilic layer, the printing plate material can be heated to further strengthen the adhesion between the hydrophilic layer and the image. When the hydrophilic layer contains a photothermal conversion material, this heat treatment can also be performed using infrared laser irradiation or flash exposure using a known xenon lamp or the like.

  Another method includes a method using a known ink jet method. Examples of the ink to be used include oil-based ink disclosed in Japanese Patent No. 2995075, hot melt ink disclosed in Japanese Patent Laid-Open No. 10-24550, and solid and hydrophobic at normal temperature disclosed in Japanese Patent Laid-Open No. 10-157053. An oil-based ink in which resin particles are dispersed or a water-based ink in which thermoplastic resin particles that are solid and hydrophobic at room temperature are dispersed can be used. As an aspect of the present invention, a radiation-curable ink is preferably used. Can do.

  This radiation curable ink is composed of at least a polymerizable compound. Further, a coloring material can be added for the purpose of obtaining visible image quality.

  As the color material, a color material that can be dissolved or dispersed in the main component of the polymerizable compound, that is, various dyes and pigments can be used. When adding a pigment, since the dispersibility has a great influence on the degree of coloration, the pigment is appropriately dispersed. For the dispersion of the pigment, a ball mill, a sand mill, an attritor, a roll mill, an agitator, a Henschel mixer, a colloid mill, an ultrasonic homogenizer, a pearl mill, a wet jet mill, a paint shaker, or the like can be used. It is also possible to add a dispersant when dispersing the pigment. A polymer dispersant is preferably used as the dispersant. Examples of the polymer dispersing agent include Solsperse series manufactured by Zeneca. Moreover, it is also possible to use a synergist corresponding to various pigments as a dispersion aid. These dispersants and dispersion aids are preferably added in an amount of 1 to 50 parts by mass with respect to 100 parts by mass of the pigment. Although the dispersion medium is a solvent or a polymerizable compound, the radiation curable ink used is preferably solvent-free because it reacts and cures immediately after ink landing. If the solvent remains in the cured image, the solvent resistance deteriorates and the VOC (volatile organic compound) problem of the remaining solvent arises. Therefore, it is preferable in view of dispersibility that the dispersion medium is not a solvent but a polymerizable compound, and among them, a monomer having the lowest viscosity is selected.

  For the dispersion, it is preferable that the average particle diameter is 0.08 to 0.5 μm, and the pigment, the dispersant, and the dispersion medium are selected so that the maximum particle diameter is 0.3 to 10 μm, preferably 0.3 to 3 μm. Set dispersion conditions and filtration conditions. By controlling the particle size, clogging of the head nozzle can be suppressed, and ink storage stability, ink transparency, and curing sensitivity can be maintained.

  The color material is preferably added in an amount of 0.1 to 10% by mass based on the entire ink.

  As the radiation polymerizable compound, a radical polymerizable compound, for example, a photopolymerizable composition described in JP-B No. 7-31399, JP-A Nos. 7-159983, 8-224982, 10-863 and the like was used. Photocurable materials and cationic polymerization photocurable resins are known, and recently, photocationic polymerization photocurable resins sensitized to a long wavelength region longer than visible light are also disclosed in, for example, -43633, 8-324137 and the like.

  The radical polymerizable compound is a compound having an ethylenically unsaturated bond capable of radical polymerization, and any compound having at least one ethylenically unsaturated bond capable of radical polymerization in the molecule may be used. Those having chemical forms such as monomers, oligomers and polymers are included. Only one radical polymerizable compound may be used, or two or more radical polymerizable compounds may be used in combination at an arbitrary ratio in order to improve the desired properties. A polyfunctional compound having two or more functional groups is more preferable than a monofunctional compound. More preferably, two or more polyfunctional compounds are used in combination for controlling performance such as reactivity and physical properties.

  Examples of compounds having an ethylenically unsaturated bond capable of radical polymerization include unsaturated carboxylic acids such as acrylic acid, methacrylic acid, itaconic acid, crotonic acid, isocrotonic acid, maleic acid and their salts, esters, urethanes, amides. And radically polymerizable compounds such as various unsaturated polyesters, unsaturated polyethers, unsaturated polyamides and unsaturated urethanes. Specifically, 2-ethylhexyl acrylate, 2-hydroxyethyl acrylate, butoxyethyl acrylate, carbitol acrylate, cyclohexyl acrylate, tetrahydrofurfuryl acrylate, benzyl acrylate, bis (4-acryloxypolyethoxyphenyl) propane, neopentyl glycol Diacrylate, 1,6-hexanediol diacrylate, ethylene glycol diacrylate, diethylene glycol diacrylate, triethylene glycol diacrylate, tetraethylene glycol diacrylate, polyethylene glycol diacrylate, polypropylene glycol diacrylate, pentaerythritol triacrylate, pentaerythritol Tetraacrylate, dipentaery Acrylic acid derivatives such as lithol tetraacrylate, trimethylolpropane triacrylate, tetramethylolmethane tetraacrylate, oligoester acrylate, N-methylol acrylamide, diacetone acrylamide, epoxy acrylate; methyl methacrylate, n-butyl methacrylate, 2-ethylhexyl methacrylate , Lauryl methacrylate, allyl methacrylate, glycidyl methacrylate, benzyl methacrylate, dimethylaminomethyl methacrylate, 1,6-hexanediol dimethacrylate, ethylene glycol dimethacrylate, triethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, polypropylene glycol dimethacrylate, trimethylol Methacryl derivatives such as tan trimethacrylate, trimethylolpropane trimethacrylate, 2,2-bis (4-methacryloxypolyethoxyphenyl) propane; and other derivatives of allyl compounds such as allyl glycidyl ether, diallyl phthalate, triallyl trimellitate More specifically, Yamashita Junzo “Cross-linking agent handbook” (1981 Taiseisha), Kato Kiyosumi “UV · EB curing handbook (raw material)” (1985, polymer publication society), Commercially available products described in “Application and Market of UV / EB Curing Technology”, p. 79, (1989, CMC), “Polyester Resin Handbook” by Eiichiro Takiyama (1988, Nikkan Kogyo Shimbun) Or radically polymerizable or crosslinkable monomers, oligomers and Polymers can be used. The amount of the radical polymerizable compound added is preferably 1 to 97% by mass, more preferably 30 to 95% by mass.

  Cationic polymerization type photo-curing resin includes monomers that are polymerized by cationic polymerization (mainly epoxy type), epoxy-type UV curable prepolymer, prepolymer containing two or more epoxy groups in one molecule. Etc. Examples of such prepolymers include alicyclic polyepoxides, polyglycidyl esters of polybasic acids, polyglycidyl ethers of polyhydric alcohols, polyglycidyl ethers of polyoxyalkylene glycol, and polyglycidyl ethers of aromatic polyols. And hydrogenated compounds of polyglycidyl ethers of aromatic polyols, urethane polyepoxy compounds and epoxidized polybutadienes. One of these prepolymers can be used alone, or two or more thereof can be mixed and used.

  As the polymerizable compound, a (meth) acrylic monomer or prepolymer, an epoxy monomer or prepolymer, a urethane monomer or prepolymer, or the like is preferably used, and the following compounds are more preferable.

  2-ethylhexyl-diglycol acrylate, 2-hydroxy-3-phenoxypropyl acrylate, 2-hydroxybutyl acrylate, hydroxypivalate neopentyl glycol diacrylate, 2-acryloyloxyethyl phthalate, methoxy-polyethylene glycol acrylate, tetramethylol Methane triacrylate, 2-acryloyloxyethyl-2-hydroxyethylphthalic acid, dimethylol tricyclodecane diacrylate, ethoxylated phenyl acrylate, 2-acryloyloxyethyl succinic acid, nonylphenol EO adduct acrylate, modified glycerin triacrylate Bisphenol A diglycidyl ether acrylic acid adduct, modified bisphenol A diacrylate, phenoxy-polyethylene Glycol acrylate, 2-acryloyloxyethyl hexahydrophthalic acid, bisphenol A PO adduct diacrylate, bisphenol A EO adduct diacrylate, dipentaerythritol hexaacrylate, pentaerythritol triacrylate tolylene diisocyanate urethane prepolymer, lactone Modified towable acrylate, butoxyethyl acrylate, propylene glycol diglycidyl ether acrylic acid adduct, pentaerythritol triacrylate hexamethylene diisocyanate urethane prepolymer, 2-hydroxyethyl acrylate, methoxydipropylene glycol acrylate, ditrimethylolpropane tetraacrylate, penta Erythritol triacrylate hexamethylene Isocyanate urethane prepolymer, stearyl acrylate, isoamyl acrylate, isomyristyl acrylate, isostearyl acrylate.

  These acrylate compounds have less skin irritation and sensitization (rash) than conventional polymerizable compounds used in UV curable inks, can lower the viscosity, and have stable ink ejection properties. The obtained polymerization sensitivity and adhesion to the recording medium are also good. 20-95 mass% of the said compound group is used, Preferably it is 50-95 mass%, More preferably, 70-95 mass% is used.

  The monomers listed in the above-mentioned polymerizable compounds have low sensitization even with a low molecular weight, and have high reactivity, low viscosity, permeability to hydrophilic layers and adhesion. Excellent. Furthermore, in order to further improve the sensitivity, bleeding, and adhesion with the hydrophilic layer, it is possible to use the above-mentioned monoacrylate together with a polyfunctional acrylate monomer or polyfunctional acrylate oligomer having a molecular weight of 400 or more, preferably 500 or more. It is preferable in terms of improving sensitivity and adhesion. While maintaining safety, the sensitivity, bleeding, and adhesion to the recording medium can be further improved. As the oligomer, an epoxy acrylate oligomer and a urethane acrylate oligomer are particularly preferable.

  It is preferable to use a monoacrylate selected from the above compound group in combination with a polyfunctional acrylate monomer or a polyfunctional acrylate oligomer, because the film can be made flexible and the film strength can be increased while improving adhesion. As monoacrylate, stearyl acrylate, i-amyl acrylate, i-mystil acrylate, i-stearyl acrylate have high sensitivity, low shrinkage, can suppress the strength reduction due to internal stress in the image area, and further prevent bleeding. It is preferable in terms of the odor of the printed matter and the cost reduction of the irradiation device.

  Although methacrylate has better skin irritation than acrylate, sensitization is generally not different from acrylate and is not suitable because it has lower sensitivity than acrylate, but has high reactivity and good sensitization. If it is a thing, it can be used conveniently. Among the above compounds, alkoxy acrylate has low sensitivity and causes problems of bleeding, odor, and irradiation light source. Therefore, it is preferable to stop the amount to be less than 70 parts by mass and use other acrylates in combination.

  If necessary, other components can be added to the ink.

  When an electron beam, X-ray, or the like is used as irradiation light, an initiator is not necessary. However, when UV light, visible light, or infrared light is used as a radiation source, a radical polymerization initiator or initiator corresponding to each wavelength is used. Add auxiliaries, sensitizing dyes, etc. These amounts require 1-10 parts by weight of the total ink. Various known compounds can be used as the initiator, but the initiator is selected from those that dissolve in the polymerizable compound. Specific examples of the initiator include xanthone or thioxanthone series, benzophenone series, quinone series, and phosphine oxide series. Moreover, in order to improve preservability, 200-20000 ppm of a polymerization inhibitor can be added.

  The ink of the present invention is preferably heated and reduced in viscosity in the range of 40 to 80 ° C. and ejected. Therefore, it is preferable to add a polymerization inhibitor in order to prevent head clogging due to thermal polymerization.

  In addition to this, surfactants, leveling additives, matting agents, polyester resins, polyurethane resins, vinyl resins, acrylic resins, rubber resins, and waxes are added to adjust film properties as necessary. I can do it. In order to improve adhesion to recording media such as olefin and PET, it is preferable to include a tackifier that does not inhibit polymerization. Specifically, high molecular weight adhesive polymer described in JP-A-2001-49200, pages 5 to 6 (ester of (meth) acrylic acid and alcohol having an alkyl group having 1 to 20 carbon atoms, (meta ) A copolymer of acrylic acid and an ester of an alicyclic alcohol having 3 to 14 carbon atoms, an ester of (meth) acrylic acid and an aromatic alcohol having 6 to 14 carbon atoms), or a polymerizable unsaturated bond A low molecular weight tackifying resin.

  In order to improve the adhesion to the hydrophilic layer, it is also effective to add a very small amount of an organic solvent. In this case, it is effective to add in a range that does not cause the problem of solvent resistance and VOC, and the amount is 0.1 to 5%, preferably 0.1 to 3%.

  In addition, as a means for preventing a decrease in sensitivity due to the light-shielding effect due to the ink coloring material, a radical-cation hybrid type curable ink can be obtained by combining a cationic polymerizable monomer having a long initiator lifetime and an initiator.

  The composition ratio of the ink is determined so that the temperature at the time of ejection is preferably 7 to 30 mPa · s, and more preferably 7 to 20 mPa · s, in consideration of ejection properties. The ink viscosity at 25 ° C. is preferably 35 to 500 mPa · s, more preferably 35 to 200 mPa · s. By increasing the viscosity at room temperature, it is possible to prevent ink from penetrating into porous recording media, to reduce uncured monomers and to reduce odor, and to suppress dot bleeding at the time of landing, improving image quality. Is done. If it is less than 35 mPa · s, the effect of preventing bleeding is small, and if it is more than 500 mPa · s, a problem occurs in the delivery of the ink liquid.

  The surface tension is preferably 200 to 300 μN / cm, more preferably 230 to 280 μN / cm. If it is less than 200 μN / cm, there is concern in terms of bleeding and penetration, and if it exceeds 300 μN / cm, there is concern in terms of wettability.

(Photothermal conversion agent)
The hydrophilic layer, the lower layer and the image forming layer of the printing plate material of the present invention realize high sensitivity by containing the following photothermal conversion material.

  The following metal oxides can be added to the hydrophilic layer as photothermal conversion materials.

A material that is black in the visible light region, or a material that is conductive or is a semiconductor. Examples of the former include black iron oxide (Fe ₃ O ₄ ) and black mixed metal oxides containing two or more of the aforementioned metals. The latter includes, for example, SnO ₂ doped with Sb (ATO), In ₂ O ₃ doped with Sn (ITO), TiO ₂ and TiO ₂ with reduced TiO (titanium oxynitride, generally titanium black) ) And the like. Further, it can also be used as the core material of _{(BaSO 4, TiO 2, 9} Al 2 O 3 · 2B 2 O, K 2 O · nTiO 2 , etc.) were coated with these metal oxides. These particle sizes are 0.5 μm or less, preferably 100 nm or less, and more preferably 50 nm or less. Of these photothermal conversion materials, black composite metal oxides containing two or more metals are more preferred materials.

  Specifically, it is a composite metal oxide composed of two or more metals selected from Al, Ti, Cr, Mn, Fe, Co, Ni, Cu, Zn, Sb, and Ba. These can be produced by the methods disclosed in JP-A-8-27393, 9-25126, 9-237570, 9-241529, 10-231441 and the like.

  The composite metal oxide used in the present invention is particularly preferably a Cu-Cr-Mn-based or Cu-Fe-Mn-based composite metal oxide. In the case of a Cu—Cr—Mn system, it is preferable to perform the treatment disclosed in JP-A-8-273393 in order to reduce the elution of hexavalent chromium. These composite metal oxides are colored with respect to the amount added, that is, have good photothermal conversion efficiency.

  These composite metal oxides preferably have an average primary particle size of 1 μm or less, and more preferably have an average primary particle size in the range of 0.01 to 0.5 μm. When the average primary particle diameter is 1 μm or less, the photothermal conversion ability with respect to the addition amount becomes better, and when the average primary particle diameter is within the range of 0.01 to 0.5 μm, the photothermal conversion ability with respect to the addition amount. Is better. However, the photothermal conversion ability with respect to the addition amount is greatly affected by the degree of dispersion of the particles, and the better the dispersion, the better. Therefore, it is preferable to disperse these composite metal oxide particles by a known method separately before adding them to the layer coating solution to prepare a dispersion (paste). If the average primary particle size is less than 0.01, it is not preferable because dispersion becomes difficult. A dispersing agent can be appropriately used for the dispersion. The addition amount of the dispersant is preferably 0.01 to 5% by mass, and more preferably 0.1 to 2% by mass with respect to the composite metal oxide particles.

  The addition amount of these composite metal oxides is 20% or more and less than 40%, more preferably 25% or more and less than 39%, more preferably 25% or more and less than 30%, based on the total solid content of the hydrophilic layer. Range. If the addition amount is less than 20%, sufficient sensitivity cannot be obtained, and if it is 40% or more, ablation defects due to ablation occur.

  In the present invention, the following infrared absorbing dye can be added as a photothermal conversion material to the hydrophilic layer and the image forming layer of the printing plate material.

General infrared absorbing dyes such as cyanine dyes, croconium dyes, polymethine dyes, azurenium dyes, squalium dyes, thiopyrylium dyes, naphthoquinone dyes, anthraquinone dyes, organic compounds such as phthalocyanine dyes and naphthalocyanine dyes , Azo, thioamide, dithiol, and indoaniline organometallic complexes. Specifically, JP-A-63-139191, JP-A-64-33547, JP-A-1-160683, JP-A-280750, JP-A-1-293342, JP-A-2-2074, JP-A-3-26593, Described in 3-30991, 3-34891, 3-36093, 3-36094, 3-36095, 3-42281, 3-97589, 3-103476, etc. The compound of this is mentioned. These can be used alone or in combination of two or more.
The addition amount of these infrared absorbing dyes is 0.1% or more and less than 10%, more preferably 0.3% or more and less than 7%, more preferably 0.5%, based on the total solid content of the image forming layer. The range is less than 6%. If the added amount deviates from this, as described above, if the added amount is less than 0.1%, sufficient sensitivity cannot be obtained, and if it is 10% or more, ablation residue due to ablation occurs.

(Back coat layer)
In the present invention, it is preferable to have at least one constituent layer on the opposite side of the image forming functional layer of the support in order to handle and prevent physical property changes during storage. Preferred constituent layers are an undercoat layer, a hydrophilic binder-containing layer, or a hydrophobic binder-containing layer, and the binder-containing layer may be coated on the undercoat layer.

  As the undercoat layer, the above-described undercoat layer of the support is preferable. The hydrophilic binder is not particularly limited as long as it is hydrophilic. Polyvinyl alcohol (PVA), which is a resin having a hydroxyl group as a hydrophilic structural unit, a cellulose resin {methyl cellulose (MC), ethyl cellulose (EC), Hydroxyethylcellulose (HEC), carboxymethylcellulose (CMC), etc.}, chitins, and starch; polyethylene oxide (PEO), polypropylene oxide (PPO), polyethylene glycol (PEG), and polyvinyl ether (PVE), which are resins having an ether bond And polyacrylamide (PAAM) and polyvinylpyrrolidone (PVP), which are resins having an amide group or an amide bond. In addition, polyacrylates, maleic resins, alginates and gelatins having carboxyl groups as dissociable groups; polystyrene sulfonates having sulfone groups; amino groups, imino groups, tertiary amines and quaternary ammonium salts Examples thereof include polyallylamine (PAA), polyethyleneimine (PEI), epoxidized polyamide (EPAm), polyvinylpyridine, and gelatin.

  The hydrophobic binder is not particularly limited as long as it is hydrophobic as a binder. For example, polymers derived from α, β-ethylenically unsaturated compounds such as polyvinyl chloride, copolymers of vinyl chloride and vinylidene chloride, vinyl chloride and A copolymer of vinyl acetate, polyvinyl acetate and partially hydrolyzed polyvinyl acetate, a polyvinyl acetal made from polyvinyl alcohol as a starting material, wherein only some of the repeating vinyl alcohol units can be reacted with an aldehyde, Preferable examples include polyvinyl butyral, a copolymer of acrylonitrile and acrylamide, polyacrylic acid ester, polymethacrylic acid ester, polystyrene and polyethylene, or a mixture thereof.

  The hydrophobic binder is obtained from an aqueous dispersion resin (polymer latex) described in paragraphs “0033” to “0038” of JP-A No. 2002-258469 if the finished printing plate material surface is hydrophobic. It could be

In the present invention, it is necessary to contain a matting agent in the back coating layer in order to prevent color misalignment in color printing due to easy attachment to a printing press and misalignment of the printing plate during printing. The matting agent to be contained may be used regardless of porous, non-porous, organic resin particles, and inorganic fine particles. Examples of the inorganic matting agent include silica, alumina, zirconia, titania, carbon black, graphite, TiO ₂ , BaSO ₄ , ZnS, MgCO ₃ , CaCO ₃ , ZnO, CaO, WS ₂ , MoS ₂ , MgO, SnO ₂ , Al ₂ O ₃ , α-Fe ₂ O ₃ , α-FeOOH, SiC, CeO ₂ , BN, SiN, MoC, BC, WC, titanium carbide, corundum, artificial diamond, garnet, garnet, silica, triboli, diatomaceous earth, dolomite, etc., organic matting agents include polyethylene fine particles, fluororesin particles, guanamine resin particles, acrylic resin particles, silicon resin particles, Examples include melamine resin particles. Examples of the inorganic clothing matting agent include particles obtained by coating organic particles such as PMMA, polystyrene, and melamine with inorganic particles having a particle diameter smaller than that of the core particles. The particle size of the inorganic particles is preferably about 1/10 to 1/100 of the core particles. In addition, as the inorganic particles, known metal oxide particles such as silica, alumina, titania, zirconia and the like can be used. Various known methods can be used as the coating method, but the core material particles and the coating material particles are collided at high speed in the air such as a hybridizer to cause the coating material particles to bite into the surface of the core material particles. A dry coating method of fixing and coating is preferably used.

  Also, particles obtained by metal plating a core material of organic particles can be used. Examples of such particles include “Micropearl AU” manufactured by Sekisui Chemical Co., Ltd. in which resin particles are plated with gold.

  Particularly in the case of a product form wound in a roll shape, it is preferable to use organic resin particles because the matting agent of the backcoat layer suppresses scratches on the image forming layer. In addition, the average particle diameter of the matting agent in the present invention can be obtained by calculating a circle equivalent light from the projected area using an electron microscope.

  The particle size is preferably 1 to 12 μm, more preferably 1.5 to 8 μm, still more preferably 2 to 7 μm. When the particle diameter exceeds 12 μm, scratches on the image forming layer are likely to occur, and conversely, with 1 μm particles, plate lifting occurs on the plate cylinder.

  The addition amount of the matting agent is preferably 0.2 to 30% by mass, and more preferably 1 to 10% by mass based on the entire back coat layer.

  Further, the laser recording apparatus or the processless printing machine has a sensor for controlling the conveyance of the printing plate inside the apparatus, and in order to perform the control without delay, the constituent layers include a dye and a pigment. It is preferable to contain. As the dye and the pigment, an infrared absorbing dye and a black pigment such as carbon black used for the above-described photothermal conversion material are preferably used. Furthermore, a known surfactant can be contained.

  EXAMPLES Hereinafter, although an Example demonstrates this invention, the embodiment of this invention is not limited to this. Unless otherwise specified, “%” in the examples represents “mass%”.

<Production of support>
Using terephthalic acid and ethylene glycol, PET of IV (inherent viscosity) = 0.66 dl / g (measured at 25 ° C. in phenol / tetrachloroethane = 6/4 (mass ratio)) was obtained according to a conventional method. This is pelletized, dried at 130 ° C. for 4 hours, melted at 300 ° C., extruded from a T-die, rapidly cooled on a cooling drum at 50 ° C., and not yet thick enough to have an average film thickness of 175 μm after heat setting. A stretched film was prepared. With respect to the drawing temperature, the first drawing was stretched 1.3 times at 102 ° C. and the second drawing was longitudinally stretched 2.6 times at 110 ° C. Next, it was stretched 4.5 times at 120 ° C. with a tenter. Thereafter, the film was heat-fixed at 240 ° C. for 20 seconds and relaxed by 4% in the lateral direction at the same temperature. Thereafter, the chuck portion of the tenter was slit, knurled at both ends, cooled to 40 ° C., and wound at 47.1 N / m. In this way, a biaxially stretched PET film having a thickness of 190 μm was obtained. The glass transition temperature (Tg) of this biaxially stretched PET film was 79 ° C. The width of the obtained PET film (film forming width) was 2.5 m. The thickness distribution of the obtained support was 3%.

<Preparation of underdrawn support>
The both sides of the support film obtained above are subjected to a corona discharge treatment of 8 W / m ² · min, and then an undercoating liquid a having the following composition is applied to one side so that the dry film thickness becomes 0.8 μm. After coating, undercoating treatment (8 W / m ² · min) is performed, and undercoat coating solution b having the following composition is applied to a dry film thickness of 0.1 μm and dried at 180 ° C. for 4 minutes. It was. After drying, the corona discharge treatment having the strength shown in Table 9 was performed to obtain undercoat samples 1 to 1 (undercoat surface A). In addition, after coating the undercoat coating solution c of the following composition on the opposite side so as to have a dry film thickness of 0.8 μm, the corona discharge treatment (8 W / m ² · min) is performed, The drawing coating solution d was applied to a dry film thickness of 1.0 μm and dried at 180 ° C. for 4 minutes. After drying, a corona discharge treatment of 8 W / m ² · min was performed (undercoating surface B).
(Undercoat coating liquid a)
Copolymer latex of styrene / glycidyl methacrylate / butyl acrylate (60/39/1) (solid content 30%, Tg = 75 ° C.) 21.00 g
Copolymer latex of styrene / glycidyl methacrylate / butyl acrylate (20/40/40) (solid content 30%, Tg = 75 ° C.) 5.60 g
Anionic surfactant S-1 0.60 g
73.00 g of pure water
(Undercoat coating liquid b)
1.00g gelatin
Anionic surfactant S-1 0.04g
Hardener H-1 0.12g
Matting agent (silica with an average particle size of 3.5 μm) 0.014 g
Preservative F-1 0.005g
99.00 g of pure water
(Undercoating liquid c)
Copolymer latex of styrene / glycidyl methacrylate / butyl acrylate / acetoacetoxyethyl methacrylate (20/40/40 /) (solid content 30%, Tg = 75 ° C.) 25.30 g
Copolymer latex of styrene / glycidyl methacrylate / butyl acrylate (39/40/20/1) (solid content 30%, Tg = 56.2 ° C.) 13.00 g
Anionic surfactant S-1 0.60 g
74.00g of pure water
(Undercoat coating solution d)
Conductive composition of d-11 / d-12 / d-13 (66/31/1) 30.00 g
Hardener H-2 6.60g
Anionic surfactant S-1 0.05g
Matting agent (silica with an average particle size of 3.5 μm) 0.01 g
63.00 g of pure water
d-11: anionic polymer compound comprising a copolymer of sodium styrenesulfonate / maleic acid (50/50) d-12: copolymer latex comprising styrene / glycidyl methacrylate / butyl acrylate = 40/40/20 d -13: high molecular weight activator comprising styrene / sodium isoprenesulfonate = 80/20

<Application of back coat layer>
The following composition was sufficiently stirred and mixed using a homogenizer, and then filtered to prepare a backcoat layer coating solution. This back coat layer coating solution is applied to the undercoated samples 1 to 8 on the support undercoating surface B side using a wire bar # 6, and the drying speed set at 100 ° C. with a length of 15 m is transported through the drying zone. It was passed at a speed of 15 m / min. The amount of force of the back-coat layer was 2.0g / m ^2.
(Backcoat layer coating solution)
Colloidal silica: Snowtex-XS (Nissan Chemical Co., Ltd., solid content 20%)
33.60g
Acrylic emulsion: DK-05 (Gifu Shellac, solid content 48%)
14.00g
Matting agent (PMMA with an average particle size of 5.5 μm) 0.56 g
51.84 g of pure water
The solid content concentration of the entire coating solution is 14%.

<Application of lower layer and upper hydrophilic layer>
The following compositions were sufficiently stirred and mixed using a homogenizer, respectively, and then filtered to prepare a lower hydrophilic layer coating solution and an upper hydrophilic layer coating solution.
(Lower hydrophilic layer coating solution)
Colloidal silica: Snowtex-XS (supra, solid content 20%) 51.94 g
Porous metal oxide: Shilton JC-40 (manufactured by Mizusawa Chemical Co., Ltd., porous aluminosilicate particles, average particle size 4 μm) 2.22 g
Surface-coated melamine resin particles: STM-6500S (Nissan Chemical Co., Ltd., average particle size 6.5 μm) 3.00 g
Layered clay mineral montmorillonite: Mineral colloid MO (manufactured by Southern Clay Products, average particle size 0.1 μm) was vigorously stirred with a homogenizer to form a 5% water-swollen gel 4.44 g
Cu-Fe-Mn-based metal oxide black pigment: TM-3550 black powder (manufactured by Dainichi Seika Kogyo Co., Ltd., particle size of about 0.1 μm) with a solid content of 40% (of which 0.2% is a dispersant) Stuff
10.00g
4% aqueous solution of sodium carboxymethylcellulose (reagent manufactured by Kanto Chemical Co., Inc.)
2.80g
0.56g of 10% aqueous solution of trisodium phosphate dodecahydrate (reagent manufactured by Kanto Chemical Co., Inc.)
25.04g of pure water
The solid content concentration of the entire coating solution is 20%.
(Upper hydrophilic layer coating solution)
Colloidal silica: Snowtex-XS (supra, solid content 30%) 5.2 g
Necklace-shaped colloidal silica: Snowtex-PSM (manufactured by Nissan Chemical Co., Ltd., solid content 20%) 11.7 g
Colloidal silica: MP-4540 (Nissan Chemical Co., Ltd., solid content 30%, average particle size 0.4 μm) 4.5 g
Porous metal oxide: Shilton JC-20 (manufactured by Mizusawa Chemical Co., Ltd., porous aluminosilicate particles, average particle size 2 μm) 1.2 g
Porous metal oxide: Shilton AMT08 (manufactured by Mizusawa Chemical Co., Ltd., porous aluminosilicate particles, average particle size 0.6 μm) 3.6 g
Layered mineral particles Montmorillonite: Mineral colloid MO (above, average particle size of about 0.1 μm) is vigorously stirred with a homogenizer to form a 5% water-swelling gel 4.8 g
Cu—Fe—Mn-based metal oxide black pigment: TM-3550 black powder (supra, particle size of about 0.1 μm), solid content 40% (of which 0.2% is a dispersant), aqueous dispersion 2.7 g
3.0 g of 4% aqueous solution of sodium carboxymethylcellulose (supra)
0.6 g of 10% aqueous solution of trisodium phosphate dodecahydrate (supra)
62.7g of pure water
The solid content concentration of the entire coating solution is 12%.

The obtained lower layer hydrophilic layer coating solution is applied to the back surface (undercoating surface A) of the support on which the backcoat layer has been applied using wire bar # 5, and is set to 100 ° C. with a length of 15 m. The dried zone was passed at a conveying speed of 15 m / min. Subsequently, the upper hydrophilic layer coating solution was applied using a wire bar # 3 and passed through a drying zone set at 100 ° C. having a length of 30 m at a conveyance speed of 15 m / min. The applied amounts of the lower layer and the upper hydrophilic layer were 3.0 g / m ² and 0.55 g / m ² , respectively. The sample after application was aged at 60 ° C. for 1 day. The applicability of the lower hydrophilic layer will be described later.

<Preparation of printing plate material>
An image forming layer coating solution having the following composition is applied on the upper hydrophilic layer formed above using a wire bar # 5, and a drying zone set at 70 ° C. having a length of 30 m is transported at a speed of 15 m / min. And an image forming layer was formed. The amount of the image forming layer applied was 0.5 g / m ² . The coated sample was aged at 50 ° C. for 2 days to obtain a printing plate material 11.
(Image forming layer coating solution)
Carnauba wax emulsion A206 (manufactured by Gifu Shellac Co., Ltd., average particle size 0.3 μm, softening point 65 ° C., melting point 80 ° C., melt viscosity 8 cps, solid content 40%) 16.0 g
Microcrystalline wax emulsion A118 (Gifu Shellac Co., Ltd., average particle size 0.5 μm, solid content 40%) 5.9 g
Sodium polyacrylate: DL-522 (manufactured by Nippon Shokubai Co., Ltd., average molecular weight 170,000, solid content 30%) 2.4 g
75.7g of pure water
The solid content concentration of the entire coating solution is 9.5%.

  This printing plate material 11 was cut into a width of 660 mm and wound about 30 m around a paper core having an outer diameter of 76 mm, to obtain a roll-shaped planographic printing plate material sample 11.

  Roll samples 12 to 18 were prepared in the same manner as the lithographic printing plate material sample 11 except that the corona discharge intensity was changed as shown in Table 1.

<Creating a printing plate>
Each of the above lithographic printing plate material roll samples was wound around an exposure drum and fixed. For the exposure, a laser beam having a wavelength of 830 nm and a spot diameter of 18 μm is used, and an image is formed by printing at 2400 dpi (dpi is the number of dots per inch, that is, 2.54 cm) and 175 lines, with an exposure energy of 240 mJ / cm ^2. Created a version.

<printing>
Each obtained printing plate was used for printing under the following conditions to evaluate each performance.

Printing device: DAIYAF-1 manufactured by Mitsubishi Heavy Industries
Printing paper: Coated paper Dampening solution: Astro Mark 3 (Nikken Chemical Laboratories) 2%
Ink: Two types are prepared and evaluated for printing. Ink-1: Toyo King High Echo M Red (manufactured by Toyo Ink)
Ink-2: TM High Echo SOY1 (manufactured by Toyo Ink, soybean oil ink)
《Printability (waste paper)》
Good S / N ratio at the time of printing (the non-image area is free of soiling, that is, the non-image area of the image forming layer is removed on the printing machine, and the density of the image area is within an appropriate range. The printing performance was evaluated by the number of printed sheets (printing waste paper) until a printed matter having a development defect due to the scratch of the image layer by the mat material of the BC layer was obtained. The smaller the number of waste paper, the better. There are practical problems with 40 sheets or more.

<Press life>
The printing end point was defined as the end point of printing when either a 3% dot missing in the image or a decrease in the density of the solid portion was confirmed.

  The results are shown in Table 1.

  As is apparent from Table 1, the lithographic printing plate material according to the present invention can be stably produced and has excellent printing performance.

Claims (8)

In a lithographic printing plate material in which an undercoat layer, a hydrophilic layer, and an image forming layer are sequentially provided on a plastic support and wound in a roll, the surface of the undercoat layer is 3 W / m ² · min or more, 40 W / m A lithographic printing plate material comprising a hydrophilic layer after a corona discharge treatment of less than ² minutes. 2. The lithographic printing plate material according to claim 1, wherein the undercoat layer has a two-layer structure. The lithographic printing plate material according to claim 1, wherein the hydrophilic layer is applied by a wire bar method. The photothermal conversion agent for converting near infrared rays into heat is contained in at least one of the hydrophilic layer and the image forming layer provided in the roll-shaped lithographic printing plate material. Planographic printing plate material. The lithographic printing plate material according to any one of claims 1 to 4, wherein the hydrophilic layer is formed by a coating step and has a two-layer structure. The lithographic printing plate material according to any one of claims 1 to 5, wherein a backcoat layer is provided on the back surface of the image forming layer side coating surface. An image is formed on the lithographic printing plate material according to any one of claims 1 to 6 using a thermal head or a thermal laser. A lithographic printing plate material according to any one of claims 1 to 6, wherein the lithographic printing plate material is laser-exposed based on image information, attached to a printing machine without being subjected to a wet development process, and printed on a printing paper.