JP2008114527A - Manufacturing method for lithographic printing plate material, and lithographic printing plate material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lithographic printing plate material which is excellent in scratch-resistance, printing durability, and on-board developing property, and to provide its manufacturing method. <P>SOLUTION: This manufacturing method for the lithographic printing plate material which has a hydrophilic layer and an image forming layer on a base material in this order has two processes. In the first process, a hydrophilic layer application liquid containing a water-soluble compound of which the solubility with 100 g of water at 25°C ranges from 0.2 g to 4.0 g is applied onto the base material and dried to install the hydrophilic layer. In the second process, after the process of installing the hydrophilic layer, an image forming layer application liquid is applied on the hydrophilic layer and dried to install the image forming layer. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a printing plate material, and more particularly to a lithographic printing plate material capable of image formation by a computer-to-plate (CTP) method.

  At present, in the field of printing, printing by the CTP method has been performed with the digitization of print image data. However, this printing is inexpensive and easy to handle and is equivalent to a conventional so-called PS plate. Therefore, there is a demand for a printing plate material for a CTP system having the following printability.

  In particular, in recent years, there has been a demand for a printing plate material that does not require development processing using a processing solution containing a special agent (for example, alkali, acid, solvent, etc.) and can be applied to a conventional printing machine. Phase change type printing plate material that does not require water, printing plate material that is processed with water or a substantially neutral processing liquid mainly composed of water, and development processing is performed at an initial stage of printing on a printing press. There are known printing plate materials called chemical-free type printing plate materials and processless type printing plate materials, such as printing plate materials that do not require a process.

  It is a thermal laser recording system having a wavelength of near infrared to infrared that is mainly used for image formation of a processless type printing plate material. Ablation type and heat fusion image layer on-machine development type, and phase change type are known, but because there is no contamination due to scattering of the image part due to ablation at the time of exposure, a fine image can be obtained, etc. A heat fusion image layer on-machine development type (see Patent Documents 1 and 2) is used relatively advantageously.

  On the other hand, in the thermal process plate, a highly sensitive printing plate material is required for reducing the load on the exposure apparatus and improving the efficiency of the plate making operation.

  As an example of a technique for increasing sensitivity, a technique is known in which a thermosensitive recording layer containing a compound capable of forming a hydrophobic region by heating or radiation irradiation is provided on a hydrophilic surface (see Patent Document 3). ).

  In addition, when a high-sensitivity thermal recording layer is used as the thermal recording layer, the recording layer in the non-image area is fixed to the hydrophilic surface due to external pressure or scratching (scratch scratches), etc., during printing. In order to prevent such stains during printing (improving scratch resistance), an intermediate layer is provided between the hydrophilic surface of the support and the thermal recording layer to avoid direct contact. Thus, a technique for suppressing scratches and dirt has been disclosed (see Patent Document 4).

  However, such a printing plate material has problems such as a decrease in image recording sensitivity and a decrease in printing durability, which is thought to be due to weak adhesion between the heat-sensitive recording layer and the hydrophilic surface of the image recording portion. . There is also a method to improve scratch resistance by adding a large amount of water-soluble resin such as polyvinyl alcohol or sodium polyacrylate to the heat-sensitive recording layer, and retaining the hydrophobized precursor, but in this case also the sensitivity decreases However, there are problems such as a decrease in printing durability and insufficient on-press developability.

Thus, in a printing plate material having a heat-sensitive recording layer, particularly a printing plate material that can be developed on-press, it is possible to obtain a lithographic printing plate material having excellent scratch resistance, excellent printing durability, and excellent on-press developability. It was difficult.
JP-A-9-123387 JP 2003-231374 A JP 2003-170670 A JP 2002-107917 A

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a lithographic printing plate material having excellent scratch resistance, excellent printing durability, and excellent on-press developability, and a method for producing the same. is there.

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

  1. A method for producing a lithographic printing plate material having a hydrophilic layer and an image forming layer in this order on a substrate, wherein a water-soluble compound having a solubility in 100 g of water at 25 ° C. of 0.2 g or more and 4.0 g or less After the step of applying the hydrophilic layer coating liquid contained on the substrate and drying to provide the hydrophilic layer, and the step of providing the hydrophilic layer, the image forming layer coating liquid on the hydrophilic layer A method for producing a lithographic printing plate material, comprising: applying and drying to form an image forming layer.

  A lithographic printing plate material produced by the method for producing a lithographic printing plate material according to 2.1.

  3. 3. The lithographic printing plate material according to 2, wherein the lithographic printing plate material is a lithographic printing plate material that can be developed on a printing press.

  According to the present invention, it is possible to provide a lithographic printing plate material having excellent scratch resistance, excellent printing durability, and excellent on-press developability, and a method for producing the same.

  Hereinafter, although the best mode for carrying out the present invention will be described, the present invention is not limited to these.

  The method for producing a lithographic printing plate material and the lithographic printing plate material of the present invention are a method for producing a lithographic printing plate material having a hydrophilic layer and an image forming layer in this order on a base material, and to 100 g of water at 25 ° C. Applying a hydrophilic layer coating solution containing a water-soluble compound having a solubility of 0.2 g or more and 4.0 g or less on the substrate and drying to provide the hydrophilic layer; and One feature is that, after the providing step, the image forming layer is provided by applying and drying an image forming layer coating solution on the hydrophilic layer.

  The reason why the lithographic printing plate material of the present invention is excellent in scratch resistance (scratch resistance) and printing durability is presumed as follows.

  Since the water-soluble compound according to the present invention has low solubility in water, it reaches a saturation concentration in the course of evaporation of water as a coating solvent in the drying process after applying the hydrophilic layer coating solution (aqueous solution) according to the present invention. Therefore, precipitation occurs in the hydrophilic layer coating film according to the present invention at that stage. When drying further proceeds, a state is formed in which the deposited water-soluble compound according to the present invention is oriented on the surface of the hydrophilic layer according to the present invention. The lithographic printing plate material of the present invention is produced by further coating and drying an image forming layer coating solution on the surface of the hydrophilic layer according to the present invention.

  By this process, a compound that is hardly soluble in water but water-soluble precipitates at the interface between the surface of the hydrophilic layer according to the present invention and the image forming layer, and forms, for example, a fragile surface existing in a fine particle state. That is, in the vicinity of the surface of the hydrophilic layer according to the present invention, the water-soluble compound according to the present invention is in a relatively high concentration state. In the lithographic printing plate material in such a state, a part of the surface of the hydrophilic layer according to the present invention can be easily removed when dampening water adheres immediately after the start of printing. The fragile region formed by the presence of the water-soluble compound according to the present invention at the interface on the surface of the hydrophilic layer according to the present invention causes the surface of the image forming layer to be subjected to external pressure or scratches, so that the image layer forming layer component is It is presumed that the fixed region can be easily developed on-machine (excellent in scratch resistance (scratch resistance)). Furthermore, since the water-soluble compound according to the present invention at this interface does not form a continuous layer generally called an intermediate layer, it does not interfere with heat fusion of the heated portion of the image forming layer. It is presumed that a lithographic printing plate material having good printing durability can be produced without increasing the amount of exposure energy necessary for image formation.

  Hereinafter, the present invention will be described in detail.

  In the planographic printing plate material of the present invention, the image forming layer is preferably formed on a substrate having the hydrophilic layer according to the present invention, and the image forming layer is preferably a layer having on-press developability.

  Specifically, as the lithographic printing plate material of the present invention, a substrate having a hydrophilic surface to be described later (for example, an aluminum plate having a grain, a hydrophilic layer (giving a hydrophilic surface to the substrate) On a resin substrate or metal substrate) on which a hydrophilic layer for forming a hydrophilic layer, i.e., a hydrophilic layer that is not a hydrophilic layer according to the present invention) is formed. And a planographic printing plate material provided with an image forming layer.

"Base material"
As the substrate according to the present invention, a substrate having a hydrophilic surface layer by hydrophilizing the substrate surface can be preferably used.

  As the base material according to the present invention, a known material used as a substrate for a printing plate can be used as long as the surface shape is within the range specified in the present invention. For example, a metal plate, a plastic film, a polyolefin, etc. And a composite substrate obtained by appropriately laminating the above materials.

  The thickness of the base material is not particularly limited as long as it can be attached to a printing press, but a thickness of 50 to 500 μm is generally easy to handle.

  As a base material which concerns on this invention, the metal plate which hydrophilized the base-material surface is used preferably.

  Examples of the metal plate include iron, stainless steel, and aluminum. In the present invention, aluminum or an aluminum alloy (hereinafter referred to as an aluminum plate) is particularly preferable because of the relationship between specific gravity and rigidity. Those subjected to any of the known roughening treatment, anodic oxidation treatment, and surface hydrophilization treatment (so-called aluminum grained plate) are more preferred.

  As an aluminum grained board, the grained board obtained by the method currently disclosed by Unexamined-Japanese-Patent No. 10-869 can be mentioned, for example.

  Various aluminum alloys can be used as the base material according to the present invention, such as silicon, copper, manganese, magnesium, chromium, zinc, lead, bismuth, nickel, titanium, sodium, iron, etc. An alloy of metal and aluminum is used.

  The aluminum plate that can be used as the 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 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 and desmutted. It is preferable to perform the 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 surface 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 for example, volcanic ash particles having a particle diameter of 10 to 100 μm on water. While supplying the uniformly dispersed slurry, the brush can be pressed. The roughening by honing polishing is performed by, for example, uniformly dispersing volcanic ash particles having a particle diameter of 10 to 100 μm in water, injecting pressure from a nozzle and injecting them obliquely to the surface of the base material. Can do. Also, for example, abrasive particles having a particle size of 10 to 100 μm are coated on the surface of the substrate so as to exist 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 sheets and applying a pressure to transfer the rough surface pattern of the sheet.

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 base material, 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 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 base material may be subjected to a 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.

  Examples of the plastic film used as the substrate include polyethylene terephthalate, polyethylene naphthalate, polyimide, polyamide, polycarbonate, polysulfone, polyphenylene oxide, cellulose esters, and the like.

  In the present invention, among these plastic films, polyester films such as polyethylene terephthalate (hereinafter sometimes abbreviated as PET) and polyethylene naphthalate (hereinafter sometimes abbreviated as PEN) are preferably used as the base material. The

  Furthermore, it is preferable to use a support obtained by the method described in JP-A No. 10-10676 and having a thermal dimensional change rate of from 0.001% to 0.04% at 120 ° C. for 30 seconds.

  A preferable polyester film is an unstretched polyester film, a uniaxially stretched polyester film, or a biaxially stretched polyester film.

  Of these, a longitudinally stretched polyester film uniaxially stretched in the film extrusion direction (longitudinal direction) is particularly preferred.

<Undercoat layer on substrate>
In the polyester film base material, easy adhesion treatment or undercoat layer coating can be performed in order to have various functions.

  Examples of the easy adhesion treatment include corona discharge treatment, flame treatment, plasma treatment, and ultraviolet irradiation treatment.

  As the undercoat layer, a layer containing gelatin or latex is preferably provided on the polyester film support. Among them, the antistatic undercoat layer described in paragraph Nos. 0044 to 0116 of JP-A-7-191433 is preferably used. Further, a conductive layer such as a conductive polymer-containing layer described in paragraph Nos. 0031 to 0073 of JP-A-7-20596 or a metal oxide-containing layer described in paragraph Nos. 0074 to 0081 of JP-A-7-20596 is provided. It is preferable. The conductive layer may be coated on either side as long as it is on the polyester 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 spots failure during printing is greatly reduced.

<< Hydrophilic layer according to the present invention >>
The lithographic printing plate material and the method for producing the lithographic printing plate material of the present invention have a solubility in 100 g of water of 25 ° C. on the aforementioned base material (which may have an undercoat layer on the base material) of 0. The hydrophilic layer coating solution according to the present invention containing 2 g or more and 4.0 g or less of the water-soluble compound according to the present invention is applied and dried to form the hydrophilic layer according to the present invention. A liquid is applied and dried to form an image forming layer.

  The hydrophilic layer according to the present invention contains the water-soluble compound according to the present invention whose solubility in 100 g of water at 25 ° C. is 0.2 g or more and 4.0 g or less.

  The solubility of the water-soluble compound according to the present invention in 100 g of water at 25 ° C. is from 0.2 g to 4.0 g, preferably from 0.3 g to 3.0 g, more preferably from 0.5 g to 2 g. 0.0 g or less. If it is less than 0.2 g, the solubility in water is too low, so that the area where the image layer forming layer component is fixed due to external pressure or scratches cannot be made on-machine developability, and the effect of preventing scratches is exhibited. It becomes difficult. On the other hand, if it is 4 g or more, the solubility in water is too high, so that a fragile surface oriented on the surface of the hydrophilic layer cannot be formed in the drying step, and it is difficult to exhibit the effect of preventing scratches. Therefore, the solubility of the water-soluble compound according to the present invention in 100 g of water at 25 ° C. is 0.2 g or more and 4.0 g or less.

  The water-soluble compound having a solubility in 100 g of 25 ° C. water of 0.2 to 4.0 g according to the present invention means “the amount dissolved in 100 g of distilled water at 25 ° C. is 0.2 to 4.0 g. Means a water-soluble compound.

  The “solubility in 100 g of distilled water at 25 ° C.” of the “water-soluble compound having a solubility in 100 g of water at 25 ° C. of 0.2 g to 4.0 g” according to the present invention is measured as follows. And shall be required.

(Measuring method)
The solubility measurement according to the present invention is carried out by adding a water-soluble compound under stirring to 100 g of distilled water kept constant at 25 ° C. using a thermostatic bath until the solution no longer dissolves (g) ).

  Examples of the water-soluble compound having a solubility in 100 g of water at 25 ° C. of 0.2 to 4 g according to the present invention include inorganic metal salts, organic acids, and water-soluble dyes. Of these, in the present invention, calcium sulfate, benzoic acid, acetanilide, fumaric acid, calcium carbonate, silver sulfate, phthalic acid, lead (II) bromide, lead (II) chloride, picric acid, lithium carbonate, calcium chromate , Magnesium chromate, potassium nitrate, aluminum nitrate, potassium bicarbonate, iron (III) nitrate, zinc sulfate, aluminum chloride, glycine, barium bromide, potassium chromate, cesium iodide, ammonium bicarbonate, lithium sulfate, magnesium sulfate, Sodium carbonate, magnesium carbonate, ammonium chromate, sodium sulfide, sodium sulfate, iron (II) sulfate, lead nitrate, barium chloride, potassium hexacyanoferrate (III), cesium nitrate, sulfur dioxide, copper (II) sulfate, oxalic acid , Sodium bicarbonate, aluminum sulfate, sodium fluoride Lithium, boric acid, potassium hexacyanoferrate (II), potassium chlorate, potassium sulfate, barium sulfide, potassium hydrogen oxalate, potassium dichromate, potassium permanganate, barium nitrate, acetylsalicylic acid, sodium oxalate, hydroxide Barium, food blue No. 2 (Indigo Carmine), food red No. 106 (Acid Red) and the like are preferable. These compounds may be used alone or in combination of two or more.

  Water is used as a solvent for the coating solution containing the water-soluble compound according to the present invention, and an organic solvent such as alcohol may be added as necessary. This coating solution may contain various surfactants for improving coating properties.

  As content with respect to the hydrophilic layer coating liquid of the water-soluble compound which concerns on this invention, 0.01 mass%-3.0 mass% are preferable, and 0.05 mass%-2.0 mass% are especially preferable. When the content is 0.01% by mass or more, the water-soluble compound according to the present invention is preferable because a fragile surface exhibiting a scratch resistance preventing effect can be uniformly formed at the interface between the hydrophilic layer and the image layer according to the present invention. On the other hand, if it exceeds 3.0% by mass, the printing durability is deteriorated. Therefore, as content with respect to the hydrophilic layer coating liquid of the water-soluble compound which concerns on this invention, 0.01 mass%-3.0 mass% are preferable.

  In the present invention, the hydrophilic layer according to the present invention is provided on a substrate. This can give a hydrophilic surface particularly suitable for the present invention.

  In this case, the hydrophilic layer according to the present invention preferably has a porous structure.

  In order to form the hydrophilic layer according to the present invention having a porous structure, the following materials for forming the hydrophilic matrix are preferably used.

  As a material for forming the hydrophilic matrix, a metal oxide is preferable.

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

  The metal oxide fine particles can be used as a binder by utilizing the film forming property. The decrease in hydrophilicity is less than when an organic binder is used, and it is suitable for use in the hydrophilic layer according to the present invention.

(Colloidal silica)
Among these, colloidal silica can be particularly preferably used. 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 size of 20 nm or less, and the colloidal silica preferably exhibits alkalinity as a colloidal solution.

  Necklace-shaped colloidal silica is a general term for an aqueous dispersion of spherical silica whose primary particle diameter is of the order of nm, and spherical colloidal silica having a primary particle diameter of 10 to 50 nm bonded to a length of 50 to 400 nm. It means colloidal silica in the form of “pearl necklace”.

  The pearl necklace shape (that is, a pearl necklace shape) means that the image of the state in which the silica particles of colloidal silica are connected and linked has a shape like a pearl necklace.

  In the present invention, porous metal oxide particles having a particle size of less than 1 μm can be contained as a porous material having a hydrophilic layer matrix structure.

(Porous metal oxide particles)
As the porous metal oxide particles, the following porous silica, porous aluminosilicate particles, or zeolite particles can be preferably used.

(Porous silica, porous aluminosilicate particles)
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 aqueous silicate solution can be obtained by drying and pulverizing, or by pulverizing the precipitate deposited by neutralization. In the dry method, silicon tetrachloride is burned together with hydrogen and oxygen to obtain silica. These particles can be controlled in their porosity and particle size by adjusting the production conditions. As the porous silica particles, those obtained from a wet gel are particularly preferable.

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

  The porosity of the particles is preferably 0.5 ml / g or more in terms of pore volume, more preferably 0.8 ml / g or more, and further preferably 1.0 to 2.5 ml / g. preferable. The pore volume is closely related to the water retention of the coating film. The larger the pore volume, the better the water retention, the less likely to get dirty during printing, and the larger the water volume latitude, but the pore volume is 0.5 ml. / G or more is preferable from the viewpoint of printing performance, and 2.5 ml / g or less is preferable from the viewpoint of durability of the coating film because the particles themselves do not become very brittle.

(Measurement method of pore volume)
Here, the pore volume is measured by using Autosorb-1 (manufactured by Cantachrome) and assuming that the voids of the powder are filled with nitrogen by nitrogen adsorption measurement using a constant volume method. Thus, the relative pressure is calculated from the nitrogen adsorption amount at 0.998.

(Zeolite particles)
Zeolite is a crystalline aluminosilicate, and is a porous body having regular three-dimensional network voids having a pore diameter of 0.3 nm to 1 nm.

  Moreover, the hydrophilic layer matrix structure which comprises the hydrophilic layer which concerns on this invention can contain a layered clay mineral particle. Examples of the layered mineral particles include kaolinite, halloysite, talc, smectite (montmorillonite, beidellite, hectorite, sabonite, etc.), clay minerals such as vermiculite, mica (mica), chlorite, hydrotalcite, layered polysilicic acid. Examples thereof include salts (kanemite, macatite, ialite, magadiite, kenyaite, etc.). In particular, the higher the charge density of the unit layer (unit layer), the higher the polarity and the higher the hydrophilicity. The charge density is preferably 0.25 or more, more preferably 0.6 or more. Examples of the layered mineral having such a charge density include smectite (charge density 0.25 to 0.6; negative charge), vermiculite (charge density 0.6 to 0.9; negative charge) and the like. In particular, synthetic fluoromica is preferable because it can be obtained with stable quality such as particle size. Further, among the synthetic fluorine mica, those that are swellable are preferable, and those that are free swell are more preferable.

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

  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 for cracks to occur, and a tough coating film can be obtained in a dry state. Moreover, in the coating liquid containing many particulate matters, sedimentation of particulate matter can be suppressed by the thickening effect of the layered clay mineral. When the particle diameter is smaller than the above range, it is preferable for increasing the uniformity of strength due to the increase in uniformity of the coating film. Moreover, it is preferable that the aspect ratio is not less than the above range in terms of an increase in the particle sedimentation suppression effect due to an increase in the number of tabular grains with respect to the addition amount and an increase in viscosity.

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

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

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

  In the present invention, a water-soluble resin may be contained. Examples of the water-soluble resin 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. Examples thereof include resins such as acrylic polymer latex, vinyl polymer latex, polyacrylamide, and polyvinylpyrrolidone. As the water-soluble resin used in the present invention, it is preferable to use a polysaccharide.

  As polysaccharides, starches, celluloses, polyuronic acids, pullulans and the like can be used, but cellulose derivatives such as methyl cellulose salts, carboxymethyl cellulose salts, hydroxyethyl cellulose salts are particularly preferable, and sodium salts and ammonium salts of carboxymethyl cellulose are preferable. More preferred. This is because an effect of forming the surface shape of the hydrophilic layer in a preferable state can be obtained by incorporating the polysaccharide into the hydrophilic layer according to the present invention.

  The surface of the hydrophilic layer according to the present invention 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, but the above-mentioned alkaline colloidal silica is applied to the hydrophilic layer coating liquid according to the present invention. When the hydrophilic layer is applied and dried, a structure having better printability can be obtained, which is preferable.

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

  In the present invention, the water-soluble resin added to the hydrophilic matrix structure part 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, tertiary amino groups and quaternary ammonium groups. Examples thereof include acrylic resin and diacrylamine. The cationic resin may be added in the form of fine particles, and examples thereof include a cationic microgel described in JP-A-6-161101.

  In addition, the coating liquid used for coating the hydrophilic layer according to the present invention can contain a water-soluble surfactant for the purpose of improving the coating property, such as Si-based or F-based. A surfactant 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 from 0.01 to 3% by mass, more preferably from 0.03 to 1% by mass, based on the entire hydrophilic layer according to the present invention (solid content as the coating solution).

  Further, the hydrophilic layer according to the present invention may contain a phosphate. In this invention, since it is preferable that the coating liquid of the hydrophilic layer which concerns on this invention is alkaline, it is preferable to add it as trisodium phosphate or disodium hydrogenphosphate as a phosphate. By adding phosphate, the effect of improving the mesh opening at the time of printing can be obtained. The addition amount of phosphate is preferably 0.1 to 5% by mass, and more preferably 0.5 to 2% by mass as an effective amount excluding hydrate.

  Thus, when providing the hydrophilic layer which concerns on this invention, as a film thickness of the hydrophilic layer which concerns on this invention, 0.01-50 micrometers is preferable, 0.2-10 micrometers is more preferable, Especially 0.5-3 micrometers Is preferred.

(Application)
Examples of the method of applying the hydrophilic layer coating liquid according to the present invention include a method using a slide coater, a curtain coating method, a wire bar method, a gravure coating, an extrusion coating method, and the like, and the coating is performed with a wire bar. The method is preferably used.

(Dry)
The manufacturing method of this invention includes the process of apply | coating the hydrophilic layer coating liquid containing the water-soluble compound which concerns on this invention on a base material as mentioned above, and drying.

  The drying temperature is preferably 30 ° C. or higher, and particularly preferably 40 ° C. or higher.

  The drying time is preferably in the range of 10 seconds to 5 minutes, more preferably in the range of 20 to 2 minutes. Further, depending on the combination of the drying temperature and the drying time, there is a possibility that the base material may be thermally damaged, and therefore it is preferable that the base material is not damaged.

  The lithographic printing plate material of the present invention having a hydrophilic layer according to the present invention is produced through the above-described steps, and has excellent scratch resistance (scratch resistance) and excellent printing durability as follows. This is presumed to be the reason.

  Since the water-soluble compound according to the present invention has low solubility in water, it reaches a saturation concentration in the course of evaporation of water as a coating solvent in the drying process after applying the hydrophilic layer coating solution (aqueous solution) according to the present invention. Therefore, precipitation occurs in the hydrophilic layer coating film according to the present invention at that stage. When drying further proceeds, a state is formed in which the deposited water-soluble compound according to the present invention is oriented on the surface of the hydrophilic layer according to the present invention. The lithographic printing plate material of the present invention is produced by further coating and drying an image forming layer coating solution on the surface of the hydrophilic layer according to the present invention.

  By this process, a compound that is hardly soluble in water but water-soluble precipitates at the interface between the surface of the hydrophilic layer according to the present invention and the image forming layer, and forms, for example, a fragile surface existing in a fine particle state. That is, in the vicinity of the surface of the hydrophilic layer according to the present invention, the water-soluble compound according to the present invention is in a relatively high concentration state. In the lithographic printing plate material in such a state, a part of the surface of the hydrophilic layer according to the present invention can be easily removed when dampening water adheres immediately after the start of printing. The fragile region formed by the presence of the water-soluble compound according to the present invention at the interface on the surface of the hydrophilic layer according to the present invention causes the surface of the image forming layer to be subjected to external pressure or scratches, so that the image layer forming layer component is It is presumed that the fixed region can be easily developed on-machine (excellent in scratch resistance (scratch resistance)). Furthermore, since the water-soluble compound according to the present invention at this interface does not form a continuous layer generally called an intermediate layer, it does not interfere with heat fusion of the heated portion of the image forming layer. It is presumed that a lithographic printing plate material having good printing durability can be produced without increasing the amount of exposure energy necessary for image formation.

<Image forming layer>
The image forming layer according to the present invention is provided by coating the image forming layer coating liquid after the hydrophilic layer according to the present invention is provided.

  The image forming layer according to the present invention is a layer capable of forming an image by imagewise exposure or imagewise heating, and is preferably a layer that can be developed on a printing press.

  Developable on the printing press means that the printing plate material can be developed with dampening water for lithographic printing or dampening water and printing ink on the printing press without any development processing after image exposure of the printing plate material. It can be transferred to.

  The image forming layer is heated imagewise by image exposure or imagewise heating to form an image.

  For imagewise heating, there is a method of imagewise heating with a direct heat source, or a method of performing image exposure with a laser or the like and heating with heat generated by exposure. In the lithographic printing plate material of the present invention, A method using image exposure using laser light is preferably used.

  The heated portion of the image forming layer becomes an image portion that is printing ink receptive during printing.

  The image-forming layer contains a hydrophobizing precursor that causes changes such as deformation, melting, and softening due to heat and hydrophobizes the image-forming layer.

  As the hydrophobizing precursor, a thermoplastic material is preferably used, and as the thermoplastic material, heat-meltable particles or heat-fusible particles are preferably used.

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

  Usable materials include paraffin, polyolefin, polyethylene wax, microcrystalline wax, fatty acid wax and the like. These have a molecular weight of about 800 to 10,000. In order to facilitate emulsification, these waxes can be oxidized to introduce polar groups such as hydroxyl groups, ester groups, carboxyl groups, aldehyde groups, and peroxide groups. Furthermore, in order to lower the softening point and improve the workability, these waxes are stearamide, linolenamide, laurylamide, myristamide, hardened beef fatty acid amide, palmitoamide, oleic acid amide, rice sugar fatty acid amide, palm 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, highly sensitive image formation can be performed.

  The heat-fusible 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.

  Moreover, the composition of the inside and the surface layer of the heat-meltable particles may be continuously changed, 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 particle | grains in a layer, 1-90 mass% of the whole layer is preferable, and 5-80 mass% is more preferable.

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

  Specific examples of the polymer constituting the polymer particles include, for example, diene (co) polymers such as polypropylene, polybutadiene, polyisoprene, and ethylene-butadiene copolymer, styrene-butadiene copolymer, Synthetic rubbers such as methyl methacrylate-butadiene copolymer, acrylonitrile-butadiene copolymer, polymethyl methacrylate, methyl methacrylate- (2-ethylhexyl acrylate) copolymer, methyl methacrylate-methacrylic acid copolymer, methyl acrylate- ( N-methylolacrylamide) copolymer, (meth) acrylic acid ester such as polyacrylonitrile, (meth) acrylic acid (co) polymer, polyvinyl acetate, vinyl acetate-vinyl propionate copolymer, vinyl acetate-ethylene copolymer Vinyl such as polymer 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 heat-fusible particles are preferably dispersible in water, and the average particle size is preferably from 0.01 to 10 μm, more preferably from the viewpoint of on-press developability and sensitivity. ~ 3 μm.

  Further, the composition of the heat fusible 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 thermoplastic fine particle in a layer, 1-90 mass% of the whole layer is preferable, and 5-80 mass% is more preferable.

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

  The microcapsules preferably have an average diameter of 0.1 to 10 μm, more preferably 0.3 to 5 μm, and even more preferably 0.5 to 3 μm.

  The image forming layer containing the heat-fusible 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 be used, but as the image forming layer, saccharides are preferably used, and oligosaccharides are particularly preferably used.

  Since the oligosaccharide quickly dissolves in water, the removal of the image forming layer in the unexposed area on the printing apparatus becomes very quick, 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 operation, 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 has a sweet taste, and is obtained by dehydrating and condensing several monosaccharides by glycosidic bonds. Oligosaccharides are a type of glycoside with sugar as an aglycon, so they are easily hydrolyzed with acid to produce monosaccharides, and are classified into disaccharides, trisaccharides, tetrasaccharides, pentasaccharides, etc., depending on the number of molecules of monosaccharides produced. Is done. The oligosaccharide in the present invention refers to those from disaccharide to decasaccharide.

  Oligosaccharides often exist as hydrates in a normal atmosphere. Moreover, the melting point differs between hydrate and anhydride.

  Among oligosaccharides, trehalose is commercially available in a relatively high purity state at a 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.

  As content of the oligosaccharide in a layer, 1-90 mass% of the whole layer is preferable, and 10-80 mass% is more preferable.

(Photothermal conversion material)
The lithographic printing plate material according to the present invention preferably has a layer containing a photothermal conversion material on the side having the image forming layer of the substrate.

  The layer having the photothermal conversion material is preferably an image forming layer or an adjacent layer thereof, and particularly preferably a hydrophilic layer adjacent to the image forming layer or an overcoat layer.

  An infrared absorbing dye or pigment can be used as the photothermal conversion material.

(Infrared absorbing dye)
Examples of infrared absorbing dyes include organic dyes such as cyanine dyes, croconium dyes, polymethine dyes, azurenium dyes, squalium dyes, thiopyrylium dyes, naphthoquinone dyes, anthraquinone dyes, which are general infrared absorbing dyes. Examples thereof include compounds, phthalocyanine-based, naphthalocyanine-based, azo-based, thioamide-based, dithiol-based, and indoaniline-based organometallic complexes.

  Specifically, JP-A-63-139191, JP-A-64-33547, JP-A-1-160683, JP-A-280750, JP-A-1-293342, JP-A-2-2074, JP-A-3-26593, 3-30991, 3-34891, 3-36093, 3-36094, 3-36095, 3-42281, 3-97589, 3-103476, 7 -43851, 7-102179, JP-A-2001-117201, and the like. These can be used alone or in combination of two or more.

  Examples of the pigment include carbon, graphite, metal, metal oxide and the like.

  As carbon, furnace black or acetylene black is particularly preferable. The particle size (d50) is preferably 100 nm or less, and more preferably 50 nm or less.

  As the graphite, fine particles having a particle size of 0.5 μm or less, preferably 100 nm or less, more preferably 50 nm or less can be used.

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

As the metal oxide, a material that is black in the visible light region or a material that is conductive or that is a semiconductor can be used. Examples of the material exhibiting black color in the visible light region include black iron oxide (Fe ₃ O ₄ ) and black mixed metal oxides containing two or more of the aforementioned metals. The metal oxide is a black complex metal oxide composed of two or more kinds of metal oxides. 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, and 10-231441.

  The composite metal oxide that can be used in the present invention is particularly preferably a Cu-Cr-Mn-based or Cu-Fe-Mn-based composite metal oxide. In the case of a Cu—Cr—Mn system, it is preferable to perform the treatment disclosed in JP-A-8-27393 in order to reduce the elution of hexavalent chromium. These composite metal oxides are colored with respect to the amount added, that is, have good photothermal conversion efficiency. These composite metal oxides preferably have an average primary particle size of 1 μm or less, and more preferably have an average primary particle size in the range of 0.01 to 0.5 μm. When the average primary particle diameter is 1 μm or less, the photothermal conversion ability with respect to the addition amount becomes better, and when the average primary particle diameter is within the range of 0.01 to 0.5 μm, the photothermal conversion ability with respect to the addition amount is obtained. Better. However, the photothermal conversion ability with respect to the addition amount is greatly affected by the degree of dispersion of the particles, and the better the dispersion, the better. Therefore, it is preferable to disperse these composite metal oxide particles by a known method separately before adding them to the layer coating solution to prepare a dispersion (paste). 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. Although the kind of dispersing agent is not specifically limited, it is preferable to use Si type surfactant containing Si element.

Examples of materials that have conductivity or are semiconductors include reduced Sb-doped SnO ₂ (ATO), Sn-added In ₂ O ₃ (ITO), TiO ₂ , and TiO ₂ . Examples thereof include TiO (titanium oxynitride, generally titanium black). Further, it is also possible to use those obtained by coating the core material _{(BaSO 4, TiO 2, 9Al} 2 O 3 · 2B 2 O, K 2 O · nTiO 2 , etc.) in these metal oxides. These particle sizes are 0.5 μm or less, preferably 100 nm or less, and more preferably 50 nm or less.

  A particularly preferable embodiment of the photothermal conversion material is that the infrared absorbing dye and the metal oxide are black complex metal oxides composed of two or more metal oxides.

  As addition amount of these photothermal conversion raw materials, it is 0.1-50 mass% with respect to the layer containing this, 1-30 mass% is preferable, and 3-25 mass% is more preferable.

《Protective layer》
A protective layer may be provided on the image forming layer. As a material used for the protective layer, the above-mentioned water-soluble resin and water-dispersible resin can be preferably used. In addition, hydrophilic overcoat layers described in JP-A Nos. 2002-19318 and 2002-86948 can also be preferably used. The amount with the protective 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.

<On-press development method>
In a preferred embodiment, the lithographic printing plate material of the present invention is a lithographic printing plate material that can be developed on a printing press.

  The lithographic printing plate material developable on a printing press in the present invention is a printing plate material having an image forming functional layer developable on a printing press, and the image forming layer developable on a printing press is as described above. After image exposure, the non-image area is removed by dampening water or dampening water and printing ink on the lithographic printing machine without processing with a special chemical agent, and the hydrophilic layer that is the non-image area is exposed. A layer that can be made with a printable printing plate.

  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. This can be done by various sequences. In such a 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.

  (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 Start printing.

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

  (3) As a sequence for starting printing, the watering roller and the ink roller are brought into contact with each other substantially simultaneously to rotate the plate cylinder 1 to several tens of times, and then printing is started.

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

Example 1
<< Production of 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 a 0.1 mass% hydrochloric acid aqueous solution at 25 ° C. for 30 seconds, neutralized, and 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. The distance between the electrode and the sample surface at this time was 10 mm. Perform electrolytic graining treatment is divided into 12 times, and the quantity of electricity used in one treatment (at a positive polarity) as the 40C / dm ^2, treatment quantity of electricity 480C / dm ² in total (at a positive polarity). In addition, a rest period of 5 seconds was provided between each surface roughening treatment.

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

  Next, after squeezing the surface water after washing with water, it was immersed in a 1% by mass sodium dihydrogen phosphate aqueous solution maintained at 70 ° C. for 30 seconds, washed with water, and then dried at 80 ° C. for 5 minutes.

[Preparation of printing plate materials 1 to 13]
<< Preparation of hydrophilic layer (1) >>
A material having the following composition was sufficiently stirred and mixed using a homogenizer, followed by filtration to prepare a coating solution for the hydrophilic layer (1) having a solid content of 32% by mass.

On the roughened aluminum plate, the hydrophilic layer (1) coating solution is applied using a wire bar so that the amount applied after drying is 4.5 g / m ² , at 120 ° C. The substrate 1 having a hydrophilic layer (1) was produced by drying for 1 minute.

<Composition of coating solution for hydrophilic layer (1)>
Composite oxide of FeO—Fe ₂ O ₃ —TiO ₂ : ETB300 (Titanium Industry Co., Ltd., solid content 40% by mass) 37.85 parts by mass Hydrophilic layer colloidal silica (alkaline): Snowtex-S (Nissan Chemical Industries) 10.10 parts by mass Necklace-shaped colloidal silica (alkaline): Snowtex-PSM (manufactured by Nissan Chemical Industries, Ltd., solid content 20% by mass) 22.74 parts by mass Colloidal silica: MP-4540 (Nissan Chemical Industry Co., Ltd., solid content 40% by mass)
8.01 parts by mass Lithium silicate: LSS-35 (manufactured by Nissan Chemical Industries, Ltd., solid content 20% by mass)
9.60 parts by mass Porous metal oxide particles: Shilton AMT08 (manufactured by Mizusawa Chemical Co., Ltd., porous aluminosilicate particles, average particle size 0.6 μm) 0.83 parts by mass Porous metal oxide particles: Shilton JC-70 ( Made by Mizusawa Chemical Co., Ltd., porous aluminosilicate particles, average particle size 6 μm) 3.2 parts by mass Water-soluble compounds of the present invention (types shown in Table 1) (weight after drying is 0.03 g / m ²⁾ Used as an aqueous solution prepared as above (7.67 parts by mass))
Amount to give 0.03 g / m ² after coating and drying Pure water Amount to give a solid content of 32% by weight in the coating solution (finished) of hydrophilic layer (1) << Image forming layer (a) Production and Production of Lithographic Printing Plate Materials 1-13 >>
Subsequently, a material having the following composition was sufficiently mixed and stirred and filtered to prepare a coating solution for the image forming layer (a) having a solid content of 5% by mass.

<Composition of coating solution for image forming layer (a)>
Carnauba wax emulsion: A118 (manufactured by Gifu Shellac Co., Ltd., average particle size 0.3 μm, softening point 65 ° C., melting point 80 ° C., melt viscosity 8 ° cps at 140 ° C., solid content 40% by mass)
9.94 parts by mass Aqueous solution of disaccharide trehalose (trade name Treha, Hayashibara Shoji, melting point 97 ° C), solid content 20% by mass 1 part by mass Sodium polyacrylate: Aquaric DL522 (manufactured by Nippon Shokubai Co., Ltd.), solid 10% by weight 6.25 parts by weight Photothermal conversion dye: 1% by weight aqueous solution of ADS830WS (manufactured by American Dye Source) 30 parts by weight Pure water 52.81 parts by weight On the hydrophilic layer (1) coated above, The coating solution for the image forming layer (a) was applied using a wire bar so that the dry weight was 0.3 g / m ² and dried at 60 ° C. for 45 seconds. Next, aging treatment was performed at 50 ° C. for 24 hours to obtain lithographic printing plate materials 1 to 13.

<< Lithographic printing plate material 14 >>
A lithographic printing plate material 14 was prepared in the same manner as in the lithographic printing plate materials 1 to 13 except that the coating solution similar to the coating solution for the hydrophilic layer (1) was applied except that it did not contain the water-soluble compound of the present invention. did.

"Evaluation methods"
<Image formation by infrared laser exposure>
The lithographic printing plate material was wound around the exposure drum and fixed. For the exposure, a laser beam having a wavelength of 830 nm and a spot diameter of about 18 μm was used, and the exposure energy was changed to 150, 175, 200, 225, and 250 mJ / cm ^2, and 2400 dpi (dpi was 1 inch, that is, 2.54 cm per 2.54 cm). An image was formed with 175 lines. The exposed image includes a solid image and a 1 to 99% halftone dot image.

<Printing method>
Printing machine: DAIYA1F-1 manufactured by Mitsubishi Heavy Industries, Ltd., coated paper, dampening water: 2% by mass of Astro Mark 3 (manufactured by Nikken Chemical Laboratory), ink (TK High Unity Red manufactured by Toyo Ink Co., Ltd.) Used to print. The lithographic 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.

<Printing evaluation>
(Scratch resistance)
For each of the above lithographic printing plate materials, scratch resistance was determined by the following method (scratch test) and used as an index of scratch resistance.

Scratch test Shinto Kagaku Co., Ltd. continuous load type scratch strength tester Tribogear TYPE: 18 / 18L, 0.5mmφ sapphire needle, load: 25g, 50g, 100g, 200g, 300g, moving speed: 500mm / min, surface After repeatedly rubbing, printing was performed to confirm the influence on the printed matter. The load at which scratching is observed (visual observation) is shown as an index of scratch resistance.

(Print life)
The number of printed sheets at the time when the 3% halftone image started to be missing was used as an index of printing durability.

(On-press developability)
For each lithographic printing plate material, the number of sheets printed from the start of printing was determined to obtain a print with good image quality. The on-machine development end index is that the non-image area is not smudged on the printed material, the density of the solid image area is 1.5 or more (measured in the M mode using Macbeth RD918), and 90% The halftone image is open.

  The results are shown in Table 1.

  From Table 1, it can be seen that the lithographic printing plate material produced by the method for producing a lithographic printing plate material of the present invention has excellent scratch resistance, excellent printing durability, and excellent on-press developability.

Claims (3)

A method for producing a lithographic printing plate material having a hydrophilic layer and an image forming layer in this order on a substrate, wherein a water-soluble compound having a solubility in 100 g of water at 25 ° C. of 0.2 g or more and 4.0 g or less After the step of applying the hydrophilic layer coating liquid contained on the substrate and drying to provide the hydrophilic layer, and the step of providing the hydrophilic layer, the image forming layer coating liquid on the hydrophilic layer A method for producing a lithographic printing plate material, comprising: applying and drying to form an image forming layer. A lithographic printing plate material produced by the method for producing a lithographic printing plate material according to claim 1. The planographic printing plate material according to claim 2, wherein the planographic printing plate material is a planographic printing plate material that can be developed on a printing press.