JP2005297232A - Printing plate material laminate, printing plate and printing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a slip sheet for a printing plate material excellent in initial inking properties and stain recoverability when an on-press developable printing plate material is stored over a long period of time under a state of the printing plate material laminate having each slip sheet left between the printing plate materials, and to provide a printing plate material laminate, a printing plate and a printing method. <P>SOLUTION: In the printing plate material laminate, which is formed by laminating the on-press developable printing plate material having Sa of 0.05-2.0 μm under the condition that let Sa be the center-line means roughness Ra of the surface on the side of at least one image forming layer provided on an aluminum base material and the slip-sheet contacting with the surface of the printing plate material, an inequality:0.2 μm<(Sa-Pa)<1.0 μm is satisfied, wherein let Pa be the center-line mean roughness Ra of the surface on the side contacting with the side of the image forming layer of the printing plate material of the slip-sheet. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a slip sheet for a printing plate material, a printing plate material laminate, a printing plate, and a printing method.

  With the digitization of print data, there is a need for CTP (computer-to-plate) technology that is inexpensive, easy to handle, and has the same printability as the PS plate.

  In recent years, in order to reduce the burden on the global environment, there is an increasing expectation for a so-called processless CTP printing plate that does not require a developer treatment with a special chemical. Among them, in recent years, on-press developability, in which an image is formed on a printing plate material and then attached to a printing machine without being treated with a chemical solution, and unnecessary parts can be removed with ink and fountain solution and printed immediately. A printing plate material (for example, described in Patent Document 1) has a focus.

  Usually, when packaging a printing plate material using a metal such as aluminum as a support, it is common to wrap several to several tens of printing plate materials. In this case, the printing plate materials stacked during handling may rub against each other and damage the image forming layer. In addition, when cutting dozens of printing plate materials with a cutting machine called guillotine, cutting with only the printing plate material was impossible, and the guillotine blades had to be frequently replaced.

  For this reason, in order to prevent damage to the printing plate and the guillotine blade, it is common practice to sandwich a paper called interleaving paper between the printing plate materials.

  On the other hand, in the case of a printing plate material having developability on a printing press, it can be printed quickly after unnecessary parts are removed with ink and fountain solution, and so-called initial ink fillability is good. It is necessary. Further, there is a demand for a printing plate having a so-called stain recovery property that increases the amount of water and recovers the stain when the ink adheres to and stains the region where the ink is not originally applied during printing.

When stored for a long period of time in the form of a printing plate material laminate in which a slip sheet is sandwiched between printing plate materials, these inks can be recovered from initial ink build-up and soiling in the case of printing plate materials that can be developed on a conventional printing press. There was a problem of inferiority.
JP-A-9-123387 (Claims, Examples)

  It is an object of the present invention to provide a printing plate material that can be developed on a printing machine for a long period of time in a state of a printing plate material laminate in which an interleaf sheet is sandwiched between printing plate materials. It is an object to provide an excellent slip sheet for a printing plate material, a printing plate material laminate, a printing plate, and a printing method.

  The above object of the present invention can be achieved by the following configuration.

(Claim 1)
Development on a printing press having at least one image forming layer on an aluminum substrate, where Sa is the center line average roughness Ra of the image forming layer side surface, and Sa is 0.05 to 2.0 μm In a printing plate material laminate formed by laminating a possible printing plate material and a slip sheet in contact with the surface of the printing plate material, a side of the slip sheet that is in contact with the image forming layer side of the printing plate material A printing plate material laminate having the relationship of the following formula 1 when the center line average roughness Ra of the surface is Pa.

Formula 1 0.2 μm <(Sa−Pa) <1.0 μm
(Claim 2)
The printing plate material laminate according to claim 1, wherein the image forming layer contains heat-meltable fine particles or heat-fusible fine particles.

(Claim 3)
The center line average roughness Ra of the surface of the printing plate material that can be developed on the printing press and the center line average roughness Ra of the surface in contact with the image forming layer side of the slip sheet used when laminating a plurality of the printing plate materials A slip sheet for a printing plate material, wherein the relationship corresponds to Formula 1 according to claim 1.

(Claim 4)
An image forming layer after forming an image with a thermal head or a thermal laser using the printing plate material taken out of the printing plate material laminate after storing the printing plate material laminate according to claim 1 or 2 for one day or more A printing plate produced by a step of removing a non-image portion of the above on a printing press.

(Claim 5)
A non-image of an image forming layer after forming an image with a thermal head or a thermal laser using the printing plate material taken out from the printing plate material laminate after storing the printing plate material laminate according to claim 1 or 2 The printing method characterized by including the process of removing a part on a printing machine.

  According to the present invention, a printing plate material that can be developed on a printing machine stored for a long time in a state of a printing plate material laminate in which a slip sheet is sandwiched between printing plate materials is excellent in initial ink setting property and stain recovery property. A slip sheet for a printing plate material, a printing plate material laminate, a printing plate and a printing method were obtained.

  The present invention will be described in more detail. The centerline average roughness Ra as used in the present invention is a three-dimensional roughness measurement measured under the condition of 23 ° C. and 48% RH after the sample to be measured is allowed to stand for 24 hours at 23 ° C. and 48% RH. The center line average roughness Ra is defined by JIS-B-0601 of JIS surface roughness. That is, the centerline average roughness (Ra) by analog measurement is obtained by extracting a portion of the measurement length L from the roughness curve in the direction of the centerline and setting the cut-off value as 0.8 mm to X. When the axis and the direction of the vertical magnification are represented by the Y axis and the roughness curve is represented by Y = f (X), the value obtained by the following formula is represented by micrometers (μm).

The average roughness (Ra) of the center line (center plane) measured by three-dimensional digital measurement is a specific sampling length, and the height of M points in the X direction and N points in the Y direction, and the total height of the MN points are measured. Then, a roughness curved surface with the roughness center plane height set to 0 is obtained, and the height Z at the measurement point of the kth point in the X direction and the jth point in the Y direction is f (Z _jk ), The value obtained is expressed in micrometers (μm).

  Examples of the measuring apparatus that can measure the center line (center plane) average roughness (Ra) by three-dimensional digital measurement include a RSTPLUS non-contact three-dimensional micro surface shape measurement system manufactured by WYKO.

  In the present invention, the center line average roughness of the surface on the image forming layer side of the printing plate material is 0.05 to 2.0 μm, and the interleaving paper has a relationship of the average center line roughness of the surface within the scope of the present invention. Any device can be used as long as it has a configuration such that it is not particularly limited. In order to make the interleaf and the printing plate material have the relationship of the above formula 1, it can be achieved by appropriately adjusting the interleaf, the aluminum base, and the constituent layers on the image forming layer side as described below.

  As the paper material used for the interleaving paper of the present invention, natural pulp such as wood pulp and hemp, synthetic pulp obtained from linear polymers such as polyolefin, synthetic fiber, regenerated cellulose and the like can be used. Further, conventionally used additives can be used, for example, fillers such as clay, talc and titanium white, wet strength improvers such as melamine resin, polyamide and polyamine epichlorohydrin resin, and drying such as starch and polyacrylamide. A fixing agent such as a strength improver, a water-soluble polyvalent metal salt such as aluminum sulfate, a cationic starch, or a cationic polymer can be used. The slip sheet of the present invention can be produced from the above components by a known method.

  The method of adjusting the average line center roughness of the interleaving paper within the scope of the present invention includes the types of fiber materials as raw materials and beating conditions, selection of fillers for internal addition and application, types of chemicals used and use The adjustment from the material side and manufacturing conditions is mentioned like quantity and usage. As another adjustment method, particles such as a matting agent can be contained. As examples of the matting agent, silica particles, PMMA particles, calcium carbonate particles, metal oxide particles (alumina, titanium oxide, etc.) can be used. A preferable average particle diameter is 0.5 μm or more and 20 μm or less, and a preferable addition amount is 0.01 g or more and 0.2 g or less. Furthermore, it is preferable to adjust the center line average roughness by improving the surface state by various calendering treatments and lamination of polyethylene resin in the paper making process.

  Next, the aluminum substrate used in the present invention will be described. As the aluminum base material that can be used in the present invention, an aluminum base material made of aluminum or an aluminum alloy (hereinafter also referred to as aluminum) is used from the relationship between specific gravity and rigidity. Various aluminum alloys can be used. For example, an alloy of a metal such as silicon, copper, manganese, magnesium, chromium, zinc, lead, bismuth, nickel, titanium, sodium, iron, and aluminum is used. The thickness of the aluminum substrate is not particularly limited as long as it can be attached to a printing press, but a thickness of 50 to 500 μm is generally easy to handle.

  The aluminum substrate used in the present invention is more preferably one that has been subjected to any of the known roughening treatment, anodizing treatment, or surface hydrophilization treatment, that is, aluminum grain. The aluminum grain may be produced by any method, but one of the production methods for obtaining the surface shape defined in the present invention is the method disclosed in JP-A-10-869. Can do.

  The aluminum substrate according to the present invention is preferably subjected to a degreasing treatment in order to remove the rolling oil on the surface prior to roughening (graining treatment). As the degreasing treatment, a degreasing treatment using a solvent such as trichlene or thinner, an emulsion degreasing treatment using an emulsion such as kesilon or triethanol, or the like is used. In addition, an alkaline aqueous solution such as caustic soda can be used for the degreasing treatment. When an alkaline aqueous solution such as caustic soda is used for the degreasing treatment, dirt and oxide film that cannot be removed only by the degreasing treatment can be removed. When an alkaline aqueous solution such as caustic soda is used for the degreasing treatment, smut is generated on the surface of the aluminum base material. In this case, it is immersed in an acid such as phosphoric acid, nitric acid, sulfuric acid, chromic acid, or a mixed acid thereof. It is preferable to perform a desmut treatment.

Examples of the roughening method include a mechanical method and a method of etching by electrolysis. The mechanical roughening method used is not particularly limited, but a brush polishing method and a honing polishing method are preferable. The roughening by the brush polishing method is, for example, rotating a rotating brush using brush bristles having a diameter of 0.2 to 0.8 mm, and watering, for example, volcanic ash particles having a particle size of 10 to 100 μm on the aluminum substrate surface. While supplying the slurry dispersed uniformly, the brush can be pressed. The roughening by honing polishing is performed, for example, by uniformly dispersing volcanic ash particles having a particle size of 10 to 100 μm in water, injecting them with pressure from a nozzle, and colliding with the surface of the aluminum base material obliquely. be able to. Also, for example, abrasive particles having a particle diameter of 10 to 100 μm are present on the surface of the aluminum substrate at a density of 2.5 × 10 ³ to 10 × 10 ³ particles / cm ² at intervals of 100 to 200 μm. Roughening can also be performed by laminating the coated sheets and transferring the rough surface pattern of the sheet by applying pressure.

After roughening by the above-mentioned mechanical roughening method, it is preferable to immerse in an aqueous solution of acid or alkali in order to remove the abrasive that has digged into the surface of the aluminum substrate, formed aluminum scraps and the like. Examples of the acid include sulfuric acid, persulfuric acid, hydrofluoric acid, phosphoric acid, nitric acid, hydrochloric acid, and the like. Examples of the base include sodium hydroxide and potassium hydroxide. Among these, it is preferable to use an aqueous alkali solution such as sodium hydroxide. The dissolution amount of aluminum in the support surface, 0.5 to 5 g / m ² is preferred. After the immersion treatment with an alkaline aqueous solution, it is preferable to carry out a neutralization treatment by immersion in an acid such as phosphoric acid, nitric acid, sulfuric acid, chromic acid or a mixed acid thereof.

The electrochemical surface roughening method is not particularly limited, but a method of electrochemical surface roughening in an acidic electrolyte is preferable. As the acidic electrolytic solution, an acidic electrolytic solution usually used in an electrochemical surface roughening method can be used, but a hydrochloric acid-based or nitric acid-based electrolytic solution is preferably used. As the electrochemical surface roughening method, for example, methods described in Japanese Patent Publication No. 48-28123, British Patent No. 896,563 and Japanese Patent Laid-Open No. 53-67507 can be used. This roughening method can be generally performed by applying a voltage in the range of 1 to 50 volts, but is preferably selected from the range of 10 to 30 volts. Current density may be in the range of 10 to 200 A / dm ^2, preferably selected from the range of 50 to 150 A / dm ^2. The quantity of electricity, may be in the range of 5000 C / dm ^2, preferably selected from the range of 100~2000c / dm ^2. The temperature at which the roughening method is performed can be in the range of 10 to 50 ° C, but is preferably selected from the range of 15 to 45 ° C.

When electrochemical surface roughening is performed using a nitric acid-based electrolyte as the electrolyte, it can be generally performed by applying a voltage in the range of 1 to 50 volts, but is selected from the range of 10 to 30 volts. Is preferred. Current density may be in the range of 10 to 200 A / dm ^2, preferably selected from the range of 20 to 100 A / dm ^2. The quantity of electricity, may be in the range of 5000 C / dm ^2, preferably selected from the range of 100~2000c / dm ^2. The temperature at which the electrochemical roughening method is performed can be in the range of 10 to 50 ° C, but is preferably selected from the range of 15 to 45 ° C. The concentration of nitric acid in the electrolytic solution is preferably 0.1 to 5% by mass. If necessary, nitrates, chlorides, amines, aldehydes, phosphoric acid, chromic acid, boric acid, acetic acid, oxalic acid, and the like can be added to the electrolytic solution.

When a hydrochloric acid-based electrolyte is used as the electrolyte, it can be generally applied by applying a voltage in the range of 1 to 50 volts, but is preferably selected from the range of 2 to 30 volts. Current density may be in the range of 10 to 200 A / dm ^2, preferably selected from the range of 50 to 150 A / dm ^2. The quantity of electricity, may be in the range of ^{100~5000c / dm 2, 100~2000c / dm} 2, and more preferably selected from the range of 200~1000c / dm ^2. The temperature at which the electrochemical roughening method is performed can be in the range of 10 to 50 ° C, but is preferably selected from the range of 15 to 45 ° C. The concentration of hydrochloric acid in the electrolytic solution is preferably 0.1 to 5% by mass.

After the surface is roughened by the electrochemical surface roughening method, it is preferably immersed in an acid or alkali aqueous solution in order to remove aluminum scraps on the surface. Examples of the acid include sulfuric acid, persulfuric acid, hydrofluoric acid, phosphoric acid, nitric acid, hydrochloric acid, and the like. Examples of the base include sodium hydroxide and potassium hydroxide. Among these, it is preferable to use an alkaline aqueous solution. The dissolution amount of aluminum in the support surface, 0.5 to 5 g / m ² is preferred. In addition, it is preferable that after the immersion treatment with an alkaline aqueous solution, neutralization treatment is performed by immersion in an acid such as phosphoric acid, nitric acid, sulfuric acid, chromic acid or a mixed acid thereof.

  The mechanical surface roughening method and the electrochemical surface roughening method may each be used alone for roughing, or the mechanical surface roughening method followed by the electrochemical surface roughening method. You may roughen.

Following the roughening treatment, anodizing treatment is preferably performed. There is no restriction | limiting in particular in the method of the anodizing process which can be used in this invention, A well-known method can be used. By performing the anodizing treatment, an oxide film is formed on the aluminum substrate. For the anodizing treatment, a method of electrolyzing an aqueous solution containing sulfuric acid and / or phosphoric acid at a concentration of 10 to 50% as an electrolytic solution at a current density of 1 to 10 A / dm ² is preferably used. A method of electrolysis at a high current density in sulfuric acid described in Japanese Patent No. 1,412,768, a method of electrolysis using phosphoric acid described in US Pat. No. 3,511,661, chromium Examples thereof include a method using a solution containing one or more acids, oxalic acid, malonic acid and the like. The formed anodic oxidation coating amount is suitably 1 to 50 mg / dm ² , preferably 10 to 40 mg / dm ² . The anodized coating amount is obtained by, for example, immersing an aluminum plate in a chromic phosphate solution (85% phosphoric acid solution: 35 ml, prepared by dissolving 20 g of chromium (IV) oxide in 1 L of water) to dissolve the oxide film, It is obtained from mass change measurement before and after dissolution of the coating on the plate.

  The anodized aluminum base material may be subjected to sealing treatment as necessary. These sealing treatments can be performed using known methods such as hot water treatment, boiling water treatment, water vapor treatment, sodium silicate treatment, dichromate aqueous solution treatment, nitrite treatment, and ammonium acetate treatment.

  Further, after these treatments, as a hydrophilization treatment, a water-soluble resin such as polyvinylphosphonic acid, a polymer or copolymer having a sulfonic acid group in the side chain, polyacrylic acid, a water-soluble metal salt ( For example, zinc borate) or a primer coated with a yellow dye, an amine salt or the like is also suitable. Further, a sol-gel treated substrate in which a functional group capable of causing an addition reaction by a radical as disclosed in JP-A No. 5-304358 is covalently used.

(Image forming layer)
A preferred embodiment of the printing plate material used in the present invention includes an embodiment having an image forming layer developable on a printing press on a hydrophilic surface aluminum base material or hydrophilic layer. The image forming layer forms an image by heat generated by exposure with an infrared laser, and contains a photothermal conversion material, heat fusible particles, heat fusible particles, and the like.

(Photothermal conversion material)
Examples of photothermal conversion materials include the following materials.

  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-based, thioamide-based, dithiol-based, and indoaniline-based organometallic complexes. Specifically, JP-A-63-139191, JP-A-64-33547, JP-A-1-160683, JP-A-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.

  In addition, compounds described in JP-A Nos. 11-240270, 11-265062, 2000-309174, 2002-49147, 2001-162965, 2002-144750, 2001-219667, etc. Can also be preferably used.

  In addition, although a pigment etc. can also be used, it is preferable to use a pigment | dye in this invention, and it is more preferable to use a pigment | dye with little coloring with visible light.

(Heat-melting fine particles and heat-fusible fine particles)
As an aspect of the present invention, the image forming layer is fused to the hydrophilic surface by an infrared laser. Examples of the material for forming an image include fine particles formed of a material generally classified as wax as the heat-meltable fine particles and the heat-fusible fine particles. The physical properties are preferably a softening point of 40 ° C. or higher and 120 ° C. or lower, a melting point of 60 ° C. or higher and 150 ° C. or lower, more preferably a softening point of 40 ° C. or higher and 100 ° C. or lower, and a melting point of 60 ° C. or higher and 120 ° C. or lower. When the melting point is less than 60 ° C., storage stability is a problem, and when the melting point is higher than 300 ° C., ink deposition sensitivity is lowered.

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

  Among these, it is preferable to contain any of polyethylene, microcrystalline, fatty acid ester, and fatty acid. Since these materials have a relatively low melting point and a low melt viscosity, high-sensitivity image formation can be performed. In addition, since these materials have lubricity, damage when a shearing force is applied to the surface of the printing plate material is reduced, and resistance to printing stains due to scratches or the like is improved.

  The heat-meltable fine particles are preferably dispersible in water, and the average particle 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, and the development on the printing press becomes insufficient, and there is a concern about soiling. When the average particle size of the heat-meltable fine particles is larger than 10 μm, the resolution is lowered.

  Further, the composition of the heat-meltable fine particles may vary continuously between the inside and the surface layer, or may be coated with a different material.

  As a coating method, a known microcapsule formation method, a sol-gel method, or the like can be used.

  As content of the heat-meltable microparticles | fine-particles in a layer, 1-90 mass% of the whole layer is preferable, and 5-80 mass% is more preferable. Examples of the heat-fusible fine particles of the present invention include thermoplastic hydrophobic polymer fine particles, and there is no specific upper limit for the softening temperature of the polymer fine particles, but the temperature is the decomposition temperature of the polymer fine particles. Lower is preferred. The mass average molecular weight (Mw) of the polymer is preferably in the range of 10,000 to 1,000,000.

  Specific examples of the polymer constituting the polymer fine particles include, for example, diene (co) polymers such as polypropylene, polybutadiene, polyisoprene, non-film-forming polyester polymer, and ethylene-butadiene copolymer. , Synthetic rubbers such as styrene-butadiene copolymer, methyl methacrylate-butadiene copolymer, acrylonitrile-butadiene copolymer, polymethyl methacrylate, methyl methacrylate- (2-ethylhexyl acrylate) copolymer, methyl methacrylate-methacryl 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 Le - vinyl esters such as ethylene (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. Among these, it is preferable to contain any of non-film-forming polyester, styrene-butadiene copolymer, and methyl methacrylate.

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

  The heat-fusible fine particles are preferably dispersible in water, and the average particle size is preferably 0.01 to 10 μm, more preferably 0.1 to 3 μm. When the average particle size is smaller than 0.01 μm, when the coating liquid for the layer containing the heat-fusible fine particles is applied onto the porous hydrophilic layer described later, the heat-fusible fine particles It becomes easy to enter into the pores or into the gaps between the fine irregularities on the surface of the hydrophilic layer, and the development on the printing press becomes insufficient, which may cause scumming. When the average particle size of the heat-fusible fine particles is larger than 10 μm, the resolution is lowered.

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

  As a coating method, a known microcapsule formation method, a sol-gel method, or the like can be used.

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

(Other materials that can be included in the image forming layer)
The image forming layer used in the present invention may further contain the following materials.

(Water-soluble resin)
In the present invention, it is preferable that at least one layer on the image forming layer side contains a water-soluble resin.

  Such a water-soluble resin is selected from hydrophilic natural polymers and synthetic polymers. Specific examples of water-soluble resins preferably used in the present invention include oligosaccharides, polysaccharides, gum arabic, water-soluble soybean polysaccharides, fibrin derivatives (for example, carboxymethyl cellulose, carboxyethyl cellulose, methyl cellulose, etc.), Modified body, white dextrin, pullulan, enzymatically-decomposed etherified dextrin, etc., polyvinyl alcohol (preferably having a saponification degree of 70 mol% or more), polyacrylic acid, alkali metal salt or amine salt thereof, polyacrylic acid copolymer, Alkali metal salt or amine salt, polymethacrylic acid, alkali metal salt or amine salt thereof, vinyl alcohol / acrylic acid copolymer and alkali metal salt or amine salt thereof, polyacrylamide, copolymer thereof, polyhydroxyethyl acrylate, polyvinyl Pyrrolidone Copolymer thereof, polyvinyl methyl ether, vinyl methyl ether / maleic anhydride copolymer, poly-2-acrylamido-2-methyl-1-propanesulfonic acid, alkali metal salt or amine salt thereof, poly-2-acrylamide- Examples thereof include 2-methyl-1-propanesulfonic acid copolymer, alkali metal salt or amine salt thereof. Moreover, these can also be used in mixture of 2 or more types according to the objective.

  Of these, oligosaccharides, polysaccharides, polyacrylic acid, polyacrylates (Na salts, etc.), and polyacrylamide are preferred.

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

  As polysaccharides, starches, celluloses, polyuronic acids, pullulans and the like can be used, but cellulose derivatives such as methyl cellulose salts, carboxymethyl cellulose salts, hydroxyethyl cellulose salts are particularly preferable, and sodium salts and ammonium salts of carboxymethyl cellulose are preferable. More preferred. The polyacrylic acid, polyacrylic acid, polyacrylate (Na salt, etc.), and polyacrylamide preferably have a molecular weight of 3,000 to 5,000,000, and more preferably 5,000 to 1,000,000.

(Crosslinking agent)
In the present invention, in order to prevent damage at the time of printing and improve the image strength, it is preferable that at least one layer on the image forming layer side contains a crosslinking agent capable of thermally crosslinking the water-soluble resin in addition to the water-soluble resin.

  Examples of crosslinking agents that can thermally crosslink water-soluble resins include cross-linkable polyfunctional compounds such as epoxy compounds, polyamine compounds, isocyanate compounds, carbodiimide compounds, silane compounds, titanate compounds, aldehyde compounds, and polyvalent metal salts. Examples thereof include compounds and hydrazine.

  Specific examples of the epoxy compound include glycerin polyglycidyl ether, polyethylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, diethylene glycol diglycidyl ether, trimethylolpropane polyglycidyl ether, trimethylolpropane polyglycidyl ether, sorbitol polyglycidyl ether, bisphenol. Or a polycondensate of these hydrogenated products and epihalohydrin. Of the above, the water-soluble epoxy compound can also be used as a water-soluble resin. As the cross-linking agent in this case, the compounds described on pages 352 to 376 of the cross-linking agent handbook (Taisei Co., Ltd. October 20, 1981, first edition, first printing) can be preferably used.

  Specific examples of the polyamine compound include ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, hexamethylenediamine, propylenediamine, polyethyleneimine, and polyamidoamine.

  Specific examples of the isocyanate compound include tolylene diisocyanate, diphenylmethane isocyanate, liquid diphenylmethane diisocyanate, polymethylene polyphenyl isocyanate, xylylene diisocyanate, naphthalene-1,5-diisocyanate, cyclohexanephenylene diisocyanate, isopropylbenzene-2,4-diisocyanate, and the like. And aromatic isocyanates such as hexamethylene diisocyanate and decamethylene diisocyanate, alicyclic diisocyanates such as cyclohexyl diisocyanate and isophorone diisocyanate, and polypropylene glycol / tolylene diisocyanate addition products.

  As the silane compound, methyltrimethoxysilane, methyltriethoxysilane, ethyltriethoxysilane, phenyltriethoxysilane, vinyltriethoxysilane, γ-aminopropyltriethoxysilane, N- (β-aminoethyl) -γ-amino Propyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, dimethyldimethoxysilane , Dimethyldiethoxysilane, diphenyldiethoxysilane, 3-chloropropylmethyldimethoxysilane, vinyltris (methylethylketoxime) silane, methyltris (methylethylketoxime) silane, Sulfonyl triacetoxysilane, and the like.

  Titanate compounds include tetraethylorthosilicate, bis (dioctylpyrophosphate) ethylene titanate, isopropyltoreactor noyl titanate, isopropyldimethacrylisostearoyl titanate, isopropylisostearoyldiacryl titanate, isopropyl (dioctylphosphate) titanate, isopropyltricumylphenyl titanate , Isopropyl tri (N-aminoethylaminoethyl) titanate, dicumylphenyloxyacetate titanate, diisostearoyl ethylene titanate, isopropyl triinstearoyl titanate, isopropyl tridodecylbenzenesulfonyl titanate, isopropyl tris (dioctyl phosphate) titanate, tetraisopropyl bis ( Octyl phosphite) titanate, tetraoctyl bis (ditridisyl phosphite) titanate, tetra (2,2-diallyloxymethyl-1-butyl) bis (ditridecyl phosphite) titanate, bis (dioctyl pyrophosphate) oxyacetate titanate Bis (dioctylpyrophosphate) oxyacetate titanate and the like.

  Examples of the aldehyde compound include formaldehyde, acetaldehyde, propyl aldehyde, butyraldehyde, glyoxal, glutaraldehyde, terephthalaldehyde, and the like.

  Examples of the polyvalent metal salt compound include water-soluble salts of metals such as zinc, calcium, magnesium, barium, strontium, cobalt, manganese and nickel.

  Among the crosslinking agents mentioned above, in particular, epoxy compounds, isocyanate compounds, carbodiimide compounds, silane compounds, aldehyde compounds, and polyvalent metal salt compounds are preferably used.

  These crosslinking agents can be used alone or in admixture of two or more. Among these cross-linking agents, a particularly preferable cross-linking agent is a water-soluble cross-linking agent, but a water-insoluble cross-linking agent can be used by being dispersed in water with a dispersant.

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

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

The amount per image forming layer, a 0.01 to 10 g / m ^2, preferably from 0.1 to 3 g / m ^2, more preferably from 0.2 to 2 g / m ^2.

(Hydrophilic overcoat layer)
In the present invention, it is preferable to have a hydrophilic overcoat layer as an upper layer of the image forming layer in order to prevent scratches during handling. The hydrophilic overcoat layer may be a layer immediately above the image forming layer, or an intermediate layer may be provided between the image forming layer and the hydrophilic overcoat layer. The hydrophilic overcoat layer is preferably removable on a printing press.

  In the present invention, the hydrophilic overcoat layer preferably contains a water-soluble resin and / or a crosslinking agent. As the water-soluble resin and the crosslinking agent, those contained in the image forming layer are used.

  In the present invention, the hydrophilic overcoat layer can contain the aforementioned photothermal conversion material.

  Further, in the present invention, a matting agent having an average particle diameter of 1 μm or more and less than 20 μm may be included in the overcoat layer in order to prevent damage when the printing plate of the present invention is mounted on a laser recording device or a printing press. By adding a matting agent to the overcoat layer, the center line average roughness on the image forming layer side of the printing plate material can be easily adjusted to 0.05 to 2.0 μm, which is preferable.

  Preferred matting agents include inorganic fine particles having a new Mohs hardness of 5 or more and organic matting agents. Examples of inorganic fine particles having a new Mohs hardness of 5 or more include metal oxide particles (silica, alumina, titania, zirconia, iron oxide, chromium oxide, etc.), metal carbide particles (silicon carbide, etc.), boron nitride particles, diamond particles, and the like. Can be mentioned. Examples of the organic matting agent include starch described in US Pat. No. 2,322,037 and the like, starch derivatives described in BE625,451 and GB981,198, and the like, and Japanese Patent Publication No. 44-3643. Polyvinyl alcohol described in U.S. Pat. No. 3,022,169, polystyrene or polymethacrylate described in CH 330,158, etc., polyacrylonitrile described in U.S. Pat. No. 3,079,257, etc. Examples include polycarbonates described in the specification and the like.

The addition amount of these matting agents is preferably 0.1 g or more and less than 10 g per 1 m ² .

  In addition, a nonionic surfactant can be mainly added to the overcoat layer in the case of aqueous solution coating for the purpose of ensuring the uniformity of coating. Specific examples of such nonionic surfactants include sorbitan tristearate, sorbitan monopalmitate, sorbitan trioleate, stearic acid monoglyceride, polyoxyethylene nonylphenyl ether, polyoxyethylene dodecyl ether and the like. . The proportion of the nonionic surfactant in the overcoat layer in the total solid is preferably 0.05 to 5 mass%, more preferably 1 to 3 mass%.

In the present invention, a dry coated amount of the overcoat layer is preferably from 0.05 to 1.5 g / m ^2, more preferred range is 0.1~0.7g / m ^2. Within this range, it is possible to satisfactorily prevent stains, prevent scratches, prevent fingerprint marks, and reduce the generation of ablation residue without impairing the removability of the overcoat layer on the printing press.

[Printing plate material laminate]
In the present invention, the printing plate material laminate refers to a form in which a slip sheet is sandwiched between the printing plate materials when a plurality of printing plate materials according to the present invention are stored. When storing the printing plate material laminate, the printing plate material laminate may be packaged as it is. A packaging material of a printing plate material having a known aluminum base material can be used as a packaging material when packaged and stored. Further, a packaging material having moisture resistance capable of blocking outside air can also be used.

(Image formation of printing plate materials)
The printing plate material according to the present invention has a so-called printing property on a printing press that can be mounted on a printing machine as it is without being treated with chemicals after image formation, and can be printed immediately after removing unnecessary portions with ink and dampening water. It is a printing plate material. In the present invention, as a preferred form, the image forming layer of the infrared laser thermal melting / fusion-bonding printing plate material has an infrared laser exposed portion as an oleophilic image portion, and the non-exposed portion layer is removed. It becomes the image part. The unexposed portion can be removed by washing with water, but it is preferable that the unexposed portion is developed on a printing press, which is removed using ink and fountain solution on the printing press. The removal of the unexposed portion of the image forming layer on the printing press can be performed by contacting a watering roller or an ink roller while rotating the plate cylinder. The various sequences can be performed. In that case, the water amount may be adjusted by increasing or decreasing the amount of dampening water required for printing, and the water amount adjustment may be divided into multiple stages or steplessly. You may change it to.

  (1) As a sequence for starting printing, a watering roller is brought into contact with the plate cylinder to make one to several dozen rotations, then an ink roller is brought into contact with the plate cylinder to make one to several dozen rotations, and then printing is performed. Start.

  (2) As a sequence for starting printing, an ink roller is brought into contact with the plate cylinder to make one to several tens of turns, then a watering roller is brought into contact with the plate cylinder to make one to several tens of turns, and then printing is performed. Start.

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

  EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto.

<Production of slip sheet>
(Interleaf P-1)
Bleached kraft pulp was beaten, and 0.4% by mass of rosin-based sizing agent was added to the paper stock diluted to a concentration of 4%, and aluminum sulfate was added so that pH = 5. The paper stock was coated with 5.0% by weight of a paper strength agent containing starch as a main component, and papermaking was performed to prepare a 40 g / m ² slip sheet having a moisture content of 5%.

(Interleaf P-2)
The interleaving paper P-1 was calendered to change the surface roughness to obtain interleaving paper P-2.

(Interleaf P-3)
After making the interleaving paper P-1, a 5 μm film made of high-pressure low density polyethylene (LDPE) was laminated on both sides of the interleaving paper P-1 to obtain P-3.

(Measurement of centerline surface roughness Ra of slip sheet)
After conditioning the interleaving paper at 23 ° C. and 48% RH for 24 hours, the center line average roughness Ra of the interleaving paper that contacts the image forming layer side of the printing plate material is RSTPLUS non-contact tertiary manufactured by WYKO. Using the original micro surface profile measurement system, the measurement was performed 40 times and under the same temperature and humidity conditions. The obtained results are shown in Table 3.

<< Preparation of aluminum substrate >>
(Aluminum substrate 1)
An aluminum plate (material 1050, tempered H16) having a thickness of 0.24 mm was immersed in a 1% by mass sodium hydroxide aqueous solution at 50 ° C., dissolved so that the dissolved amount became 2 g / m ² , and washed with water. Then, it was immersed in 0.1 mass% hydrochloric acid aqueous solution at 25 ° C. for 30 seconds, neutralized, and then washed with water.

  Next, after squeezing the surface water after washing with water, it was immersed in a 0.5% by mass No. 3 sodium silicate aqueous solution kept at 70 ° C. for 30 seconds, washed with water, dried at 80 ° C. for 5 minutes, and aluminum A substrate 1 was obtained.

(Aluminum substrate 2)
An aluminum plate (material 1050, tempered H16) having a thickness of 0.24 mm was immersed in a 1% by mass sodium hydroxide aqueous solution at 50 ° C., dissolved so that the dissolved amount became 2 g / m ² , and washed with water. Then, it was immersed in 0.1 mass% hydrochloric acid aqueous solution at 25 ° C. for 30 seconds, neutralized, and then washed with water.

Next, this aluminum plate was subjected to electrolytic surface roughening treatment with an electrolytic solution containing hydrochloric acid 10 g / L and aluminum 0.5 g / L using a sine wave alternating current and a peak current density of 50 A / dm ^2. It was. At this time, the distance between the electrode and the aluminum plate surface was 10 mm. Perform electrolytic graining treatment is divided into 12 times, and the quantity of electricity used in one treatment (at a positive polarity) as the 40C / dm ^2, treatment quantity of electricity 480C / dm ² in total (at a positive polarity). In addition, a rest time of 4 seconds was provided between each surface roughening treatment.

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

  Next, after squeezing the surface water after washing with water, it was immersed in a 0.5% by mass No. 3 sodium silicate aqueous solution kept at 70 ° C. for 30 seconds, washed with water, dried at 80 ° C. for 5 minutes, and aluminum A substrate 2 was obtained.

(Aluminum substrate 3)
In the production of the aluminum base material 1, the aluminum base material was processed in the same manner except that the amount of processing electricity (at the time of anode) was changed to 60 C / dm ² and the total amount of processing electricity (at the time of anode) was 720 C / dm ^2. 3 was obtained.

<Preparation of printing plate material>
On the prepared aluminum substrates 1 to 3, the following prepared image forming layer coating solution and overcoat layer coating solution were applied with a coater in the combinations shown in Table 3 so as to have a dry weight under the following conditions. Then, it was dried under the following conditions, and then an aging treatment was performed to obtain a printing plate material.

Application of image forming layer: Drying amount 0.75 g / m ² , drying condition 55 ° C./3 minutes Overcoat layer coating: Drying amount 0.30 g / m ² , drying condition 55 ° C./3 minutes Aging condition: 40 ° C. / 24 hours (Preparation of image forming layer coating solution)
Table 1 shows the details of the material of the image forming layer coating solution. An image forming layer coating solution was prepared by diluting and dispersing with pure water.

(Preparation of overcoat layer coating solution)
Table 2 shows details of the material of the overcoat layer coating solution. A protective layer coating solution was prepared by diluting and dispersing with pure water.

(Measurement of centerline surface roughness Ra of printing plate material)
Each of the produced printing plate materials is conditioned at 23 ° C. and 48% RH for 24 hours, and the center line average roughness Ra on the image forming layer side is measured using a WYKO RSTPLUS non-contact three-dimensional micro surface shape measurement system. Measurement was performed under the same temperature and humidity conditions at 40 times. The obtained results are shown in Table 3.

(Evaluation methods)
100 sheets of each interleaving paper and printing plate material (size: 72cm x 65cm) are alternately stacked, stored for 3 days in an environment of 23 ° C and 80% RH, and then imaged by the following infrared laser exposure to form a printing press The printing performance was evaluated.

(Image formation by infrared laser exposure)
The printing plate material was wound around the exposure drum and fixed. A laser beam having a wavelength of 830 nm and a spot diameter of about 18 μm was used for exposure, exposure energy was 250 mJ / cm ² , and an image was formed with 2400 dpi (dpi represents the number of dots per 2.54 cm) and 175 lines. The exposed image includes a solid image and a 1 to 99% halftone dot image.

(Printing method)
Printing machine: LITHRONE 26 manufactured by Komori Corporation, coated paper, dampening solution: 2% by mass of Astro Mark 3 (manufactured by Nikken Chemical Laboratory), ink (soy oil type TK high echo SOY1 manufactured by Toyo Ink Manufacturing Co., Ltd.) Printing was carried out using a red ink. The printing plate material was attached to the plate cylinder as it was after exposure, and printed using the same printing sequence as the PS plate.

<Evaluation of initial ink fillability>
The printing start sequence was performed in the PS printing sequence, and it was evaluated at what number the ink smears in the non-image area disappeared. The smaller the number of sheets, the better the ink fillability.

(Evaluation of stain recovery)
Ordinary printing (nip of ink roller and water roller) was performed with only the ink roller niped and ink adhered to the entire surface. At that time, the number of sheets in which the non-image area in the printed material was free of contamination was evaluated. A smaller number is better.

  From Table 3, it can be seen that the samples satisfying the requirements of the present invention are excellent in initial ink setting and stain recovery.

Claims (5)

Development on a printing press having at least one image forming layer on an aluminum substrate, where Sa is the center line average roughness Ra of the image forming layer side surface, and Sa is 0.05 to 2.0 μm In a printing plate material laminate formed by laminating a possible printing plate material and a slip sheet in contact with the surface of the printing plate material, a side of the slip sheet that is in contact with the image forming layer side of the printing plate material A printing plate material laminate having the relationship of the following formula 1 when the center line average roughness Ra of the surface is Pa.
Formula 1 0.2 μm <(Sa−Pa) <1.0 μm The printing plate material laminate according to claim 1, wherein the image forming layer contains heat-meltable fine particles or heat-fusible fine particles. The center line average roughness Ra of the surface of the printing plate material that can be developed on the printing press and the center line average roughness Ra of the surface in contact with the image forming layer side of the slip sheet used when laminating a plurality of the printing plate materials A slip sheet for a printing plate material, wherein the relationship corresponds to Formula 1 according to claim 1. An image forming layer after forming an image with a thermal head or a thermal laser using the printing plate material taken out of the printing plate material laminate after storing the printing plate material laminate according to claim 1 or 2 for one day or more A printing plate produced by a step of removing a non-image portion of the above on a printing press. A non-image of an image forming layer after forming an image with a thermal head or a thermal laser using the printing plate material taken out from the printing plate material laminate after storing the printing plate material laminate according to claim 1 or 2 The printing method characterized by including the process of removing a part on a printing machine.