JP2008062614A - Dampening water composition for lithographic printing and lithographic printing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a dampening water composition for lithographic printing by which a printed material having favorable inking properties and high ink density can be obtained in lithographic printing with a lithographic printing plate made up from a photopolymerizing type lithographic printing form original plate provided with an oxygen excludable protective layer including a hydrophilic compound. <P>SOLUTION: In this lithographic printing method, dampening water prepared from the dampening water composition including organic solvent which is liquid at 20°C and boils at 150°C or higher at a pressure of 1 atm, and specified cationic surface active gent is employed. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a fountain solution for lithographic printing. In particular, the present invention relates to a fountain solution for lithographic printing that gives good ink acceptability to the plate surface image area. The present invention further relates to a lithographic printing method using a fountain solution prepared from the fountain solution for lithographic printing.

In general, a lithographic printing plate comprises an oleophilic image area that receives ink in the printing process and a hydrophilic non-image area that receives dampening water. Lithographic printing utilizes the property that water and oil-based inks repel each other, so that the oleophilic image area of the lithographic printing plate is the ink receiving area, and the hydrophilic non-image area is dampened with the water receiving area (ink non-receiving area). As described above, a difference in ink adhesion is caused on the surface of a lithographic printing plate, and after ink is applied only to an image portion, the ink is transferred to a printing medium such as paper and printed. In lithographic printing, the non-image area is moistened with fountain solution to increase the interfacial chemical difference between the image area and the non-image area, thereby increasing the ink repellency of the non-image area and the ink receptivity of the image area. Increases are made.
In order to produce this lithographic printing plate, a lithographic printing plate precursor (PS plate) in which an oleophilic photosensitive resin (image recording layer) is provided on a hydrophilic support has been widely used. Such a lithographic printing plate precursor is exposed through an original image such as a lithographic film, and then a portion to be an image portion of the image recording layer is left, and the other unnecessary image recording layer is made an alkaline developer or organic A lithographic printing plate is obtained by dissolving and removing with a solvent and making a plate by a method in which the surface of the hydrophilic support is exposed to form a non-image area.

On the other hand, in recent years, digitization technology for electronically processing, storing, and outputting image information by a computer has become widespread, and various new image output methods corresponding to such digitization technology will be put into practical use. It is becoming. Along with this, digitized image information is carried by high-convergence radiation such as laser light, and the lithographic printing plate precursor is scanned and exposed with that light, directly without using a lithographic film. Computer-to-plate (CTP) technology has been attracting attention.
Further, after the lithographic printing plate precursor is exposed, a step of dissolving and removing an unnecessary image recording layer with a developer or the like is performed. However, such additional wet processing is made unnecessary or simplified. Has also been considered. As one of such simple plate making methods, an image recording layer that can remove an unnecessary part of a lithographic printing plate precursor in a normal printing process is used. After exposure, a non-image part is formed on a printing machine. A method called on-press development has been proposed which is removed to obtain a lithographic printing plate. As a specific method of on-press development, for example, a method using a lithographic printing plate precursor having an image recording layer that can be dissolved or dispersed in a dampening water, an ink solvent, or an emulsion of a dampening water and an ink, Method of mechanically removing the image recording layer by contact with rollers or blankets of a printing press, cohesion of the image recording layer or adhesion between the image recording layer and the support by penetration of dampening water, ink solvent, etc. There is a method in which the image recording layer is mechanically removed by contact with a roller or a blanket cylinder after weakening the image.

As an example of the above-described lithographic printing plate precursor for CTP, a photopolymerization lithographic printing plate precursor has been proposed. Photopolymerization type lithographic printing plate precursors generally have a polymerization initiator (a compound that initiates and accelerates polymerization of a compound having a polymerizable unsaturated group by generating radicals by the energy of light, heat, or both). Therefore, in order to suppress radical deactivation due to oxygen in the air and improve the polymerization efficiency, an oxygen-blocking protective layer is usually provided on the image recording layer. As this protective layer, polyvinyl alcohol is well known. In addition, it has been proposed that an oxygen-blocking protective layer contains an inorganic layered compound (see, for example, Patent Document 1).
The compound used in such an oxygen-blocking protective layer partially remains on the surface of the image area after development, due to its own hydrophilicity and / or on the surface of the inorganic compound in dampening water. Adsorption of the hydrophilic component may cause insufficient ink receptivity on the surface of the image area during printing, resulting in a problem of poor ink deposition, resulting in a decrease in ink density on the printed matter.

Conventionally, various proposals have been made in order to obtain a fountain solution for lithographic printing having excellent printability.
As a method of supplying dampening water to the plate surface, a continuous water supply method has become common, and in order to increase the water supply to the plate, about 10 to 30% isopropanol has been included in the dampening water. However, since isopropanol falls under the type 2 organic solvent of the Industrial Safety and Health Act, methods for replacing isopropanol have been proposed in recent years. For this reason, it has been proposed to include a specific solvent in the fountain solution. However, since these alternative technologies contain organic solvents, there are concerns about the problem of volatile organic compounds (VOC). On the other hand, it has also been proposed to include a relatively non-volatile solvent in the fountain solution. In order to solve this problem, such a non-volatile solvent has a tendency that the dampening water remaining on the plate surface when the printing press is stopped becomes water droplets, and when the water evaporates and concentrates, the image portion is dissolved and the image is damaged. It has also been proposed to add a specific compound to the fountain solution (see, for example, Patent Documents 2 and 3). Furthermore, it has been reported that a fountain solution excellent in printability is provided without substantially including a volatile organic solvent (see, for example, Patent Documents 4 and 5). In addition, it has been proposed to include a cationic compound in the processing liquid for lithographic printing (see, for example, Patent Documents 6 to 8).
Various improvements related to fountain solution have been proposed so far. In plate making and printing methods from a photopolymerization type lithographic printing plate precursor provided with an oxygen-blocking protective layer, the protective layer is caused by the hydrophilic compound. There is a need for a means for solving ink deposit failure.

JP 2005-119273 A JP-A-4-363297 JP-A-6-183171 JP 2005-271507 A JP 2005-271508 A JP-A-62-218190 JP 62-292492 A JP 7-214934 A

The object of the present invention is to eliminate the toxic and disadvantages of the conventional dampening water, and to completely replace isopropyl alcohol in a printing machine of any mechanism without requiring expert skill in printing. Another object of the present invention is to provide a fountain solution for lithographic printing. The object of the present invention is further to suppress the occurrence of printing problems such as smearing, blinding and water loss of a printing plate using a support that has been electrochemically roughened and anodized, particularly an aluminum plate, and is stable. An object of the present invention is to provide a fountain solution composition for lithographic printing, which enables continuous printing, has no safety and health problems and fire safety problems, and can obtain a high-quality printed matter. The object of the present invention is also a lithographic printing method that can be suitably used in a lithographic printing method using a lithographic printing plate subjected to conventional development processing, and in a plate making and printing method employing on-press development. It is to provide a fountain solution composition.
The object of the present invention is, in particular, in lithographic printing using a lithographic printing plate made from a photopolymerization lithographic printing plate precursor provided with an oxygen-blocking protective layer containing a hydrophilic compound, and has good ink deposition on the image area. An object of the present invention is to provide a fountain solution for lithographic printing, which can obtain a printed matter having a high ink concentration.

（式中、Ｒ¹〜Ｒ⁴は各々独立に炭素原子数１〜１２のアルキル基、ベンジル基、又はフェニル基を示し、ＺはＮ、ＰまたはＢを示し、Ｘは対イオンを示し、ＺがＮまたはＰのときはＸはアニオンを示し、ＺがＢのときはＸはカチオンを示す。） In order to achieve the above-mentioned problems, the present inventor has conducted extensive research, and as a result, by adding a specific organic solvent and a specific cationic surfactant to the fountain solution, the ink deposition property on the image area is improved. The present inventors have found that a good and high-quality printed matter can be provided, and have completed the present invention.
Therefore, the present invention is characterized by containing an organic solvent having a boiling point of 150 ° C. or higher and a liquid at 20 ° C. at one atmospheric pressure, and at least one compound selected from the compounds represented by the following formula (III): A fountain solution for lithographic printing.

Wherein R ^{1 to} R ⁴ each independently represents an alkyl group having 1 to 12 carbon atoms, a benzyl group, or a phenyl group, Z represents N, P or B, X represents a counter ion, Z When X is N or P, X represents an anion, and when Z is B, X represents a cation.)

The method of using the fountain solution composition of the present invention is not particularly limited. The fountain solution composition of the present invention can be suitably used particularly in lithographic printing using a lithographic printing plate made from a photopolymerization lithographic printing plate precursor provided with an oxygen-blocking protective layer containing a hydrophilic compound. Furthermore, the fountain solution composition of the present invention is preferably used both in a lithographic printing method using a lithographic printing plate subjected to conventional development processing, and in a plate making and lithographic printing method employing on-press development. Can do.
Accordingly, the present invention supplies a fountain solution prepared from the fountain solution composition to a lithographic printing plate obtained by making a plate from a photopolymerization lithographic printing plate precursor provided with an oxygen-blocking protective layer. Is directed to lithographic printing methods, including
The present invention also provides a dampening solution prepared from the fountain solution for lithographic printing to the plate surface after exposing the photopolymerization type lithographic printing plate precursor provided with an oxygen-blocking protective layer, and image recording It is directed to a lithographic printing process that involves removing unexposed portions of the layer.

The fountain solution composition for lithographic printing according to the present invention substitutes isopropyl alcohol in the fountain solution composition in various continuous water supply type printers without the need for specialized skill in printing work, and at the time of printing. Stable continuous printing can be performed without causing problems such as smearing of the printing plate, blinding, and water loss, and the printability is good.
According to the fountain solution composition of the present invention, in lithographic printing using a lithographic printing plate made from a photopolymerizable lithographic printing plate precursor provided with an oxygen-blocking protective layer, the ink acceptability of the surface of the image area is improved. In addition, it is possible to suppress poor ink deposition, and a high-quality printed matter having a high ink concentration can be obtained even when a large number of sheets are continuously printed.
The fountain solution for lithographic printing according to the present invention is suitably used both in a lithographic printing method using a lithographic printing plate subjected to conventional development processing, and in a plate making and lithographic printing method employing on-press development. be able to.

  Hereinafter, the present invention will be described in detail. The fountain solution is generally concentrated and commercialized when used on a commercial basis, and when used, such a concentrate is appropriately diluted and used as a fountain solution. In the present specification, the concentrated product is referred to as a fountain solution composition. The contents and addition amounts of various components mentioned below are based on the total mass of dampening water during use unless otherwise specified.

The fountain solution composition of the present invention contains an organic solvent that is liquid at 20 ° C. and has a boiling point of 150 ° C. or higher at one atmospheric pressure.
This organic solvent has a function of increasing the water absorption of the fountain solution into the plate, and is preferably one that can replace isopropyl alcohol conventionally added to the fountain solution.
Examples of the organic solvent include compounds represented by the following general formula (I).
_{^{R 1 O - (- CH 2}} CH (CH 3) -O-) m-H (I)
(In Formula (I), R ¹ represents an alkyl group having 1 to 4 carbon atoms, and m represents an integer of 1 to 3). In Formula (I), R ¹ is a linear alkyl group or a branched alkyl group. But you can. Among R ¹ , propyl group, isopropyl group, n-butyl group, isobutyl group, t-butyl group and the like are particularly mentioned.
Specific compounds of the general formula (I) include dipropylene glycol monopropyl ether, tripropylene glycol monopropyl ether, dipropylene glycol monoisopropyl ether, tripropylene glycol monoisopropyl ether, propylene glycol monobutyl ether, dipropylene glycol monobutyl ether , Tripropylene glycol monobutyl ether, propylene glycol monoisobutyl ether, dipropylene glycol monoisobutyl ether, tripropylene glycol monoisobutyl ether, propylene glycol monotertiary butyl ether, dipropylene glycol monotertiary butyl ether, tripropylene glycol monotertiary butyl ether, etc. Is mentioned. Among them, the compounds preferably used are propylene glycol monobutyl ether, propylene glycol monotertiary butyl ether, dipropylene glycol monopropyl ether, dipropylene glycol monobutyl ether, dipropylene glycol monotertiary butyl ether.

Another example of the organic solvent is a compound represented by the following formula (II).
_{HO - (- CH 2 CH (} CH 3) -O-) n-H (II)
(In formula (II), n represents an integer of 1 to 5)
Of these, propylene glycol, dipropylene glycol and tripropylene glycol are suitable.

  As another example of the organic solvent, 2-ethyl-1,3-hexanediol, ethylene glycol monomethyl ether, diethylene glycol monomethyl ether, triethylene glycol monomethyl ether, polyethylene glycol monomethyl ether, ethylene glycol monoethyl ether, diethylene glycol monoethyl ether , Triethylene glycol monoethyl ether, ethylene glycol monoisobutyl ether, diethylene glycol monoisobutyl ether, triethylene glycol monoisobutyl ether, ethylene glycol monopropyl ether, diethylene glycol monopropyl ether, triethylene glycol monopropyl ether, ethylene glycol monobutyl ether, ethylene Glycol monota Shaributyl ether, diethylene glycol monobutyl ether, diethylene glycol monotertiarybutyl butyl ether, triethylene glycol monobutyl ether, triethylene glycol monotertiary butyl ether, 3-methoxy-3-methylbutanol, 3-methoxybutanol, trimethylolpropane, molecular weight 200-1000 And polypropylene glycol of these compounds and monomethyl ether, monoethyl ether, monopropyl ether, monoisopropyl ether, monobutyl ether, monoisobutyl ether and monotertiary butyl ether of these compounds.

In the fountain solution composition of the present invention, an organic solvent that is liquid at 20 ° C. and has a boiling point of 150 ° C. or higher at one atmospheric pressure may be used alone, or two or more organic solvents may be used in combination.
The content of the organic solvent in the fountain solution is desirably sufficient water supply to the plate without using isopropyl alcohol in combination, and there is a difference depending on the water supply device of the printing press. The mass% is appropriate, preferably 0.2 to 4 mass%.

（式中、Ｒ¹〜Ｒ⁴は各々独立に炭素原子数１〜１２のアルキル基、ベンジル基、又はフェニル基を示し、ＺはＮ、ＰまたはＢを示し、Ｘは対イオンを示し、ＺがＮまたはＰのときはＸはアニオンを示し、ＺがＢのときはＸはカチオンを示す。）
上記化合物において、Ｒ¹〜Ｒ⁴が各々示す炭素原子数１〜１２のアルキル基は直鎖、分岐鎖及び環状のものを包含する。該アルキル基は置換基を有してもよく、置換基として例えばヒドロキシル基が挙げられ、置換されたアルキル基として例えば炭素原子数１〜４のヒドロキシアルキル基が挙げられる。Ｒ¹〜Ｒ⁴が各々示すフェニル基は置換基を有していてもよく、そのような置換基の例としてメチル基などの炭素原子数１〜４のアルキル基、ヒドロキシル基、ハロゲンなどが挙げられる。
ＺはＮ、ＰまたはＢを示し、ＺがＮ又はＰのときはアニオン（例えば、塩素イオン、臭素イオン、ヨウ素イオンなどのハロゲンイオン、硝酸イオン、硫酸イオン、燐酸イオン、水酸イオン、ＰＦ₆ ^-、ＢＦ₄ ^-、酢酸イオン、グリコール酸イオン、安息香酸イオンなど）を示し、ＺがＢのときはカチオン（例えばＬｉ⁺、Ｎａ⁺、Ｋ⁺などのアルカリ金属イオン又はＮＨ₄ ⁺など）を示す。 The fountain solution of the present invention further contains at least one compound selected from the compounds represented by the following formula (III).

Wherein R ^{1 to} R ⁴ each independently represents an alkyl group having 1 to 12 carbon atoms, a benzyl group, or a phenyl group, Z represents N, P or B, X represents a counter ion, Z When X is N or P, X represents an anion, and when Z is B, X represents a cation.)
In the above compound, the alkyl group having 1 to 12 carbon atoms represented by each of R ^{1 to} R ⁴ includes linear, branched, and cyclic groups. The alkyl group may have a substituent, and examples of the substituent include a hydroxyl group, and examples of the substituted alkyl group include a hydroxyalkyl group having 1 to 4 carbon atoms. The phenyl group represented by each of R ^{1 to} R ⁴ may have a substituent, and examples of such a substituent include an alkyl group having 1 to 4 carbon atoms such as a methyl group, a hydroxyl group, and halogen. It is done.
Z represents N, P or B, and when Z is N or P, anions (for example, halogen ions such as chlorine ion, bromine ion and iodine ion, nitrate ion, sulfate ion, phosphate ion, hydroxide ion, PF ₆₎ ^-, BF ₄ ^-, acetate ion, glycolate ions, shows and benzoate ion), ⁺ cation (e.g. Li when the Z is B, Na ^+, an alkali metal ion or NH ₄ ^+, etc.), such as K ⁺ Show.

Specific examples of the compound represented by the formula (III) include tetramethylammonium salt, tetraethylammonium salt, tetrabutylammonium salt, tetraoctylammonium salt, dibutyldimethylammonium salt, dioctyldimethylammonium salt, dilauryldimethylammonium salt, benzyl Trimethyl ammonium salt, benzyl triethyl ammonium salt, benzyl tributyl ammonium salt, benzyl trioctyl ammonium salt, benzyl octyl dibutyl ammonium salt, benzyl dimethyl butyl ammonium salt, benzyl dimethyl octyl ammonium salt, benzyl dimethyl lauryl ammonium salt, phenyl trimethyl ammonium salt, phenyl Triethylammonium salt, phenyltributylammonium salt, phenyltrioct Ruammonium salt, phenyldimethylbutylammonium salt, phenyldimethyloctylammonium salt, phenyldimethyllaurylammonium salt, diphenyldimethylammonium salt, diphenyldiethylammonium salt, diphenyldibutylammonium salt, diphenyldioctylammonium salt, triphenylmethylammonium salt, triphenylethyl Ammonium salts such as ammonium salt, triphenylbutylammonium salt, triphenyloctylammonium salt, tetraphenylammonium salt, and more specific examples of anions include halogen ions such as chlorine ion, bromine ion and iodine ion, nitrate ion, sulfate ion, phosphate ion, hydroxide _{^{ion, PF 6 -, BF 4 -}} , acetate ion, glycolate ions, benzoate ions Such as

Tetraphenyl phosphonium iodide, tetraphenyl phosphonium bromide, tetraphenyl phosphonium chloride, tetraphenyl phosphonium sulfate, tetraphenyl phosphonium nitrate, tetraphenyl boron sodium, tetra n-butyl phosphonium iodide, tetra n-butyl phosphonium bromide, tetra n- Butylphosphonium chloride, tetra-n-butylphosphonium sulfate, tetra-n-butylphosphonium nitrate, ethyltriphenylphosphonium bromide, benzyltriphenylphosphonium chloride, tetrabutylphosphonium hydroxide, tetrabutylphosphonium phosphate, ethyltriphenylphosphonium bromide, Butyltriphenylphosphonium bromide, diphenylphosphonium chloride , Tetra-tolyl phosphonium bromide, bis [(benzyl) (diphenyl) Hosuhoranjiiru] ammonium chloride, tetrabutyl ammonium sulfate, tetrabutylammonium nitrate and the like.

  The compound represented by the formula (III) may be used alone or in combination of two or more. In the fountain solution, the content of the compound represented by the formula (IV) is determined by the image of the ink. From the viewpoint of improving the wall-thinning property and smudges during printing, 0.005 to 1% by mass is appropriate, and preferably 0.01 to 0.1% by mass.

A water-soluble polymer compound may be further added to the fountain solution composition of the present invention.
Specific examples of such water-soluble polymer compounds include gum arabic, starch derivatives (eg, dextrin, enzymatically degraded dextrin, hydroxypropylated enzymatically degraded dextrin, carboxymethylated starch, phosphate starch, octenyl succinated starch), alginic acid. Natural products of salts, fiber derivatives (such as carboxymethylcellulose, carboxyethylcellulose, hydroxyethylcellulose, methylcellulose, hydroxypropylcellulose, hydroxypropylmethylcellulose, glyoxal modified products thereof) and modified products thereof, polyvinyl alcohol and derivatives thereof, polyvinylpyrrolidone, Polyacrylamide and its copolymer, polyacrylic acid and its copolymer, vinyl methyl ether / maleic anhydride copolymer, vinyl acetate / Compounds such as water-maleic acid copolymer. These polymer compounds can be used alone or in combination, and the addition amount thereof is 0.0001 to 5% by mass, more preferably 0.003 to 1% by mass in dampening water.

In the present invention, among the above water-soluble polymer compounds, polyvinyl pyrrolidone can be particularly preferably used. The polyvinylpyrrolidone contained in the fountain solution composition means a homopolymer of vinylpyrrolidone. Polyvinylpyrrolidone having a molecular weight of 200 to 3,000,000 is appropriate, preferably having a molecular weight of 300 to 500,000, more preferably 300 to 100,000. Particularly preferred is 300 to 30,000.
These polyvinyl pyrrolidones can be used alone or in combination of two or more kinds having different molecular weights. Further, it can be combined with a low molecular weight polyvinyl pyrrolidone, for example, a vinyl pyrrolidone oligomer having a polymerization degree of 3 to 5.
As such polyvinyl pyrrolidone, a commercially available product can be used. For example, various great grades such as K-15, K-30, K-60, K-90, K-120 manufactured by ISP can be used.
The content of polyvinyl pyrrolidone in the fountain solution is suitably 0.001 to 0.3% by mass, preferably 0.005 to 0.2% by mass.

The fountain solution is generally desirably used in the acidic region, that is, in the range of pH around 3-6. When the pH is less than 3, the etching effect on the support becomes strong and the printing durability is lowered. In order to adjust the pH value to 3 to 6, generally, an organic acid and / or an inorganic acid or a salt thereof may be added. Preferred organic acids include, for example, citric acid, maleic acid, ascorbic acid, malic acid, tartaric acid, lactic acid, acetic acid, glycolic acid, gluconic acid, hydroxyacetic acid, succinic acid, malonic acid, levulinic acid, sulfanilic acid, p-toluenesulfonic acid , Phytic acid, organic phosphonic acid and the like. Examples of the inorganic acid include phosphoric acid, nitric acid, sulfuric acid, and polyphosphoric acid. Further, alkali metal salts, alkaline earth metal salts or ammonium salts of these organic acids and / or inorganic acids, and organic amine salts are also preferably used. These organic acids, inorganic acids and / or salts thereof can be used alone. Or you may use as a mixture of 2 or more types. The addition amount is generally 0.001 to 5% by mass in dampening water.
The fountain solution composition of the present invention can also contain an alkali metal hydroxide, an alkali metal phosphate, an alkali metal carbonate, a silicate and the like, and can be used in an alkaline region near pH 7-11.

In addition to the above components, a chelate compound can also be added to the fountain solution composition of the present invention. Usually, tap water, well water, etc. are added and diluted to the fountain solution composition which is a concentrated solution, and used as the fountain solution. At this time, calcium ions or the like contained in the tap water or well water to be diluted may affect the printing and cause the printed matter to be easily stained. In such a case, the above disadvantages can be eliminated by adding a chelate compound. Preferred chelate compounds include, for example, ethylenediaminetetraacetic acid, potassium salt thereof, sodium salt thereof; diethylenetriaminepentaacetic acid, potassium salt thereof, sodium salt thereof; triethylenetetraminehexaacetic acid, potassium salt thereof, sodium salt thereof; hydroxyethylethylenediaminetriacetic acid Nitrilotriacetic acid, its potassium salt, its sodium salt; 1,2-diaminocyclohexanetetraacetic acid, its potassium salt, its sodium salt; 1,3-diamino-2-propanoltetraacetic acid, its Aminopolycarboxylic acids such as potassium salt and sodium salt thereof, 2-phosphonobutanetricarboxylic acid-1,2,4, potassium salt and sodium salt thereof; 2-phosphonobutanetricarboxylic acid- , 3,4, its potassium salt, its sodium salt; 1-phosphonoethanetricarboxylic acid-1,2,2, its potassium salt, its sodium salt; 1-hydroxyethane-1,1-diphosphonic acid, its potassium salt Organic phosphonic acids or phosphonoalkanetricarboxylic acids such as aminotri (methylenephosphonic acid), potassium salt, sodium salt, and the like.
Organic amine salts are also effective in place of the sodium or potassium salts of the above chelating agents.
These chelating agents are selected so that they are stably present in the dampening water and do not impair the printability. The amount to be added is 0.001 to 3% by mass, preferably 0.01 to 1% by mass in dampening water.

  The fountain solution composition of the present invention may contain a preservative. Specific examples of preservatives include benzoic acid and derivatives thereof, phenol or derivatives thereof, formalin, imidazole derivatives, sodium dehydroacetate, 4-isothiazolin-3-one derivatives, benztriazole derivatives, derivatives of amidine or guanidine, quaternary ammonium salts , Pyridine, quinoline or guanidine derivatives, diazine or triazole derivatives, oxazole or oxazine derivatives, halogenonitropropane compounds, bromonitroalcohol-based bromonitropropanol, 1,1-dibromo-1-nitro-2-ethanol, 3 -Bromo-3-nitropentane-2,4-diol and the like. A preferable addition amount is an amount that exerts a stable effect on bacteria, molds, yeasts, etc., and varies depending on the types of bacteria, molds, yeasts, but 0.0001-1.0 with respect to the fountain solution. The range of mass% is preferable, and it is preferable to use two or more preservatives that are effective against various molds, bacteria and yeasts.

The fountain solution composition of the present invention may further contain a colorant, a rust inhibitor, an antifoaming agent, and the like. Food coloring agents and the like can be preferably used as the colorant. For example, CI No. 19140, 15985 as a yellow dye, CI No. 16185, 45430, 16255, 45380, 45100 as a red dye, CI No. 42640 as a purple dye, CI No. 42090, 73015 as a blue dye, CI No. 42095, and the like.
Examples of the rust preventive include benzotriazole, 5-methylbenzotriazole, thiosalicylic acid, benzimidazole and derivatives thereof.
As the antifoaming agent, a silicon antifoaming agent is preferable, and any of an emulsified dispersion type and a solubilized type can be used.

  The fountain solution composition of the present invention further includes corrosion inhibitors such as magnesium nitrate, zinc nitrate, calcium nitrate, sodium nitrate, potassium nitrate, lithium nitrate and ammonium nitrate, hardeners such as chromium compounds and aluminum compounds, and cyclic ethers. : For example, an organic solvent such as 4-butyrolactone, a water-soluble surface active organometallic compound described in JP-A No. 61-193893, and the like can be added in the range of 0.0001 to 1% by mass.

  A small amount of a surfactant may be added to the fountain solution composition of the present invention. For example, anionic surfactants include fatty acid salts, abietic acid salts, hydroxyalkane sulfonic acid salts, alkane sulfonic acid salts, dialkyl sulfosuccinic acid salts, linear alkyl benzene sulfonic acid salts, branched alkyl benzene sulfonic acid salts, alkyl naphthalene. Sulfonates, alkylphenoxy polyoxyethylenepropyl sulfonates, polyoxyethylene alkylsulfophenyl ether salts, N-methyl-N-oleyl taurine sodium, N-alkylsulfosuccinic acid monoamide disodium salts, petroleum sulfonates, Hydrogenated castor oil, sulfated beef tallow oil, fatty acid alkyl ester sulfate ester salt, alkyl sulfate ester salt, polyoxyethylene alkyl ether sulfate ester salt, fatty acid monoglyceride Acid ester salts, polyoxyethylene alkylphenyl ether sulfates, polyoxyethylene styryl phenyl ether sulfates, alkyl phosphates, polyoxyethylene alkyl ether phosphates, polyoxyethylene alkylphenyl ether phosphates, styrene Examples thereof include partially saponified products of maleic anhydride copolymers, partially saponified products of olefin-maleic anhydride copolymers, and naphthalene sulfonate formalin condensates. Among these, dialkyl sulfosuccinates, alkyl sulfates and alkyl naphthalene sulfonates are particularly preferably used.

  Nonionic surfactants include polyoxyalkyl ethers, polyoxyethylene alkylphenyl ethers, polyoxyethylene polystyryl phenyl ether, polyoxyethylene polyoxypropylene alkyl ether, glycerin fatty acid partial esters, sorbitan fatty acid moieties. Esters, pentaerythritol fatty acid partial esters, propylene glycol mono fatty acid partial esters, sucrose fatty acid partial esters, polyoxyethylene sorbitan fatty acid partial esters, polyoxyethylene sorbitol fatty acid partial esters, polyglycerin fatty acid partial esters, poly Oxyethylenated castor oils, polyoxyethylene glycerin fatty acid partial esters, fatty acid diethanolamides, N, N-bis-2-hydroxy Alkylamines, polyoxyethylene alkylamines, triethanolamine fatty acid esters, such as trialkylamine oxides. Of these, polyoxyethylene alkylphenyl ethers, polyoxyethylene-polyoxypropylene block polymers and the like are preferably used.

Examples of the cationic surfactant include alkylamine salts, quaternary ammonium salts, polyoxyethylene alkylamine salts, polyethylene polyamine derivatives, and the like. Examples of amphoteric surfactants include alkyl imidazolines.
In addition, examples of the fluorine-based anionic surfactant include fluorine-based surfactants, such as perfluoroalkyl sulfonates, perfluoroalkyl carboxylates, perfluoroalkyl phosphate esters, and fluorine-based nonionic surfactants. Examples of the perfluoroalkylethylene oxide adduct, perfluoroalkylpropylene oxide adduct, and fluorine-based cationic surfactant include perfluoroalkyltrimethylammonium salts.
The content of these surfactants is 10% by mass or less, preferably 0.01 to 3.0% by mass in dampening water in view of foaming.

Furthermore, the fountain solution composition of the present invention can contain glycols and / or alcohols as a wetting agent. Examples of such wetting agents include propylene glycol, dipropylene glycol, tripropylene glycol, tetrapropylene glycol and pentapropylene glycol, ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, butylene glycol, hexylene glycol, ethyl alcohol, n -Propyl alcohol, benzyl alcohol, glycerin, diglycerin, polyglycerin, pentaerythritol and the like.
These wetting agents can be contained alone or in combination of two or more in an amount of about 0.01 to 1% by mass in dampening water.

The balance is water as a component of the fountain solution composition of the present invention.
Accordingly, in consideration of the content of the various components in the fountain solution and the dilution rate of the fountain solution composition, water, preferably demineralized water, i.e., pure water, is used to adjust the various components at appropriate concentrations. It can melt | dissolve and the fountain solution composition which is a concentrate can be obtained. Such a concentrated solution is diluted about 10 to 200 times with normal tap water, well water or the like at the time of use to obtain a dampening water at the time of use.

The fountain solution composition of the present invention can completely replace isopropyl alcohol.
Also, there is no problem in printing quality even when isopropyl alcohol up to about 15% by mass in dampening water during use is used in combination.

  The fountain solution composition of the present invention can be used for various lithographic printing plates. In particular, a photosensitive lithographic printing plate having an aluminum plate as a support and a photosensitive layer thereon (previously photosensitive). The applied printing plate is called a PS plate) and can be suitably used for a lithographic printing plate obtained by image exposure and development. A preferable example of such PS plate is a photosensitive layer comprising a mixture of a diazo resin (a salt of a condensate of p-diazodiphenylamine and paraformaldehyde) and a shellac as described in British Patent 1,350,521. On the aluminum plate, polymers having diazo resin and hydroxyethyl methacrylate unit or hydroxyethyl acrylate unit as main repeating units as described in British Patent Nos. 1,460,978 and 1,505,739 And a photosensitive polymer system containing a dimethylmaleimide group described in JP-A-2-236552 and JP-A-4-274429 was provided on an aluminum plate. A negative PS plate such as the one disclosed in JP-A-50-125806 It includes positive PS plate provided on an aluminum plate and a photosensitive layer comprising a mixture of O- Kinonjiado photosensitive material and a novolac-type phenolic resins as described in. It can also be used for a positive PS plate that has been burned.

In the composition forming the photosensitive layer, an alkali-soluble resin other than the alkali-soluble novolak resin can be blended as necessary. For example, styrene-acrylic acid copolymer, methyl methacrylate-methacrylic acid copolymer, alkali-soluble polyurethane resin, alkali-soluble vinyl resin described in JP-B-52-28401, alkali-soluble polybutyral resin, and the like. it can. Further, a PS plate having a photosensitive layer of a photopolymerizable photopolymer composition as described in US Pat. Nos. 4,072,528 and 4,072,527 on an aluminum plate, British Patent Nos. 1,235,281 and A PS plate having a photosensitive layer made of a mixture of an azide and a water-soluble polymer on an aluminum plate as described in each specification of No. 1,495,861 is also preferable.
Furthermore, it can be suitably used for a CTP plate that is directly exposed with a visible or infrared laser. Specific examples include a photopolymer type digital plate (for example, PN-V manufactured by Fuji Photo Film Co., Ltd.), a thermal positive type digital plate (for example, HP-F manufactured by Fuji Photo Film Co., Ltd.), and a thermal negative type digital plate (for example, HN-N manufactured by Fuji Photo Film Co., Ltd.).

In particular, the fountain solution composition of the present invention can be suitably used for a lithographic printing plate prepared from a photopolymerization lithographic printing plate precursor provided with an oxygen-blocking protective layer containing a hydrophilic compound.
An example of such a photopolymerization type lithographic printing plate precursor is described in JP-A-2005-119273.
As a structure of a photopolymerizable lithographic printing plate precursor in which the fountain solution composition of the present invention can be suitably used, (A) an actinic ray absorber, (B) a polymerization initiator, and (C) polymerization on a support. There is a lithographic printing plate precursor having an image recording layer containing a functional compound and an oxygen-blocking protective layer containing an inorganic layered compound in this order.

Hereinafter, the configuration, plate making and printing steps of the photopolymerizable lithographic printing plate precursor will be briefly described.
[Oxygen barrier protective layer]
The inorganic layered compound contained in the oxygen-blocking protective layer is a particle having a thin flat plate shape. For example, the following general formula: A (B, C) _2-5 D ₄ O ₁₀ (OH, F , O) ₂ [where A is any of K, Na, Ca, B and C are any of Fe (II), Fe (III), Mn, Al, Mg, V, and D is Si or Al It is. And mica groups such as natural mica and synthetic mica, talc, teniolite, montmorillonite, saponite, hectorite, zirconium phosphate and the like represented by the formula 3MgO.4SiO.H ₂ O.
In the mica group, examples of natural mica include muscovite, soda mica, phlogopite, biotite and sericite. Synthetic mica includes non-swelling mica such as fluor-phlogopite mica KMg ₃ (AlSi ₃ O ₁₀ ) F ₂ , potassium tetrasilicon mica KMg _2.5 Si ₄ O ₁₀ ) F ₂ , and Na tetrasilicic mica NaMg _2.5 ( Si ₄ O ₁₀ ) F ₂ , Na or Li teniolite (Na, Li) Mg ₂ Li (Si ₄ O ₁₀ ) F ₂ , montmorillonite Na or Li hectorite (Na, Li) _1/8 Mg _2/5 Li Examples thereof include swelling mica such as _1/8 (Si ₄ O ₁₀ ) F ₂ . Synthetic smectite is also useful.

Among the inorganic layered compounds, fluorine-based swellable mica, which is a synthetic inorganic layered compound, is particularly useful. That is, this swellable synthetic mica and swellable viscosity minerals such as montmorillonite, saponite, hectorite, bentonite, etc. have a laminated structure composed of unit crystal lattice layers with a thickness of about 10 to 15 mm, Atomic substitution is significantly greater than other viscous minerals. As a result, the lattice layer is deficient in positive charges, and cations such as Na ⁺ , Ca ²⁺ and Mg ²⁺ are adsorbed between the layers in order to compensate for this. The cations present between these layers are called exchangeable cations and exchange with various cations. In particular, when the cation between the layers is Li ⁺ or Na ⁺ , the bond between the layered crystal lattices is weak because the ionic radius is small, and the layer swells greatly with water. If shear is applied in this state, it will easily cleave and form a stable sol in water. Bentonite and swellable synthetic mica have a strong tendency and are more useful. In particular, swellable synthetic mica is preferably used.
As the shape of the inorganic layered compound to be used, from the viewpoint of diffusion control, the thinner the better, the better the plane size as long as the smoothness of the coated surface and the transmittance of actinic rays are not hindered. . Therefore, the aspect ratio is 20 or more, preferably 100 or more, particularly preferably 200 or more. The aspect ratio is the ratio of the thickness to the major axis of the particle, and can be measured, for example, from a projected view of the particle by a micrograph. The larger the aspect ratio, the greater the effect that can be obtained.

As for the particle diameter of the inorganic layered compound to be used, the average major axis is 0.3 to 20 μm, preferably 0.5 to 10 μm, particularly preferably 1 to 5 μm. The average thickness of the particles is 0.1 μm or less, preferably 0.05 μm or less, particularly preferably 0.01 μm or less. For example, among the inorganic layered compounds, the size of the swellable synthetic mica that is a representative compound is about 1 to 50 nm in thickness and about 1 to 20 μm in surface size.
When the inorganic layered compound particles having such a large aspect ratio are contained in the oxygen-blocking protective layer, the coating film strength is improved, and the permeation of oxygen and moisture can be effectively prevented. The oxygen-blocking protective layer is prevented from deteriorating, and even when stored for a long time under high-humidity conditions, the storage stability of the planographic printing plate precursor is not deteriorated due to changes in humidity, and the storage stability is excellent.
The content of the inorganic stratiform compound in the protective layer is preferably 5/1 to 1/100 by mass ratio with respect to the amount of the binder used in the protective layer. Even when a plurality of inorganic layered compounds are used in combination, the total amount of these inorganic layered compounds is preferably the above-described mass ratio.

It is preferable to use a binder together with the inorganic layered compound for the oxygen barrier protective layer.
The binder is not particularly limited as long as it has a good dispersibility of the inorganic layered compound and can form a uniform film in close contact with the image recording layer, and any of water-soluble polymers and water-insoluble polymers can be used. It can be appropriately selected and used. Specifically, for example, polyvinyl alcohol, modified polyvinyl alcohol, polyvinyl pyrrolidone, polyvinyl imidazole, polyacrylic acid, polyacrylamide, partially saponified product of polyvinyl acetate, ethylene-vinyl alcohol copolymer, water-soluble cellulose derivative, gelatin, starch Examples thereof include water-soluble polymers such as derivatives and gum arabic, and polymers such as polyvinylidene chloride, poly (meth) acrylonitrile, polysulfone, polyvinyl chloride, polyethylene, polycarbonate, polystyrene, polyamide, and cellophane. These may be used in combination of two or more as required.
Of these, water-soluble polymers are preferable from the viewpoint of easy removal of the protective layer remaining in the non-image area and handling properties during film formation, and water-soluble polymers such as polyvinyl alcohol, polyvinyl pyrrolidone, polyvinyl imidazole, and polyacrylic acid. Acrylic resin, gelatin, gum arabic, and the like are preferable. Among them, polyvinyl alcohol, polyvinyl pyrrolidone, gelatin can be applied from the viewpoint of being able to be applied using water as a solvent and easily removed by dampening water during printing. More preferred are gum arabic and the like.

  The polyvinyl alcohol that can be used in the oxygen-blocking protective layer may be partially substituted with an ester, an ether, and an acetal as long as it contains a substantial amount of unsubstituted vinyl alcohol units having the required water solubility. Similarly, a part may contain other copolymerization components. Specific examples of polyvinyl alcohol include those having a hydrolysis degree of 71 to 100 mol% and a polymerization degree in the range of 300 to 2400. Specifically, PVA-105, PVA-110, PVA-117, PVA-117H, PVA-120, PVA-124, PVA124H, PVA-CS, PVA-CST, PVA-HC, PVA- manufactured by Kuraray Co., Ltd. 203, PVA-204, PVA-205, PVA-210, PVA-217, PVA-220, PVA-224, PVA-217EE, PVA-217E, PVA-220E, PVA-224E, PVA-405, PVA-420, PVA-613, L-8 etc. are mentioned. Examples of the copolymer include 88-100 mol% hydrolyzed polyvinyl acetate chloroacetate or propionate, polyvinyl formal, polyvinyl acetal, and copolymers thereof.

The inorganic layered compound is dispersed in water by an appropriate method, and an oxygen-blocking protective layer coating solution is prepared from this dispersion. In addition to the above components, known additives such as a surfactant for improving the coating property and a water-soluble plasticizer for improving the physical properties of the film can be added to the oxygen barrier protective layer coating solution. The prepared oxygen barrier protective layer coating solution is applied on the image recording layer provided on the support and dried to form an oxygen barrier protective layer. The coating solvent can be appropriately selected in relation to the binder, but when a water-soluble polymer is used, it is preferable to use distilled water or purified water. The method for applying the oxygen-blocking protective layer is not particularly limited, and a known method such as the method described in US Pat. No. 3,458,311 or Japanese Patent Publication No. 55-49729 is applied. be able to. Specific examples of the oxygen barrier protective layer include blade coating, air knife coating, gravure coating, roll coating coating, spray coating, dip coating, and bar coating.
The coating amount of the oxygen blocking protective layer, the coating amount after drying is preferably in the range of 0.01 to 10 g / m ^2, more preferably in the range of 0.02 to 3 g / m ^2, and most preferably Is in the range of 0.02 to 1 g / m ² .

Component constituting the image recording layer [(A) actinic ray absorber]
An actinic ray absorber is a compound that absorbs light emitted from an exposure light source, efficiently generates radicals from a polymerization initiator in photon mode and / or heat mode, and contributes to improvement in sensitivity of a lithographic printing plate precursor. . The actinic ray absorber is preferably an infrared absorber when the lithographic printing plate precursor is imagewise exposed with an infrared laser, and a wavelength of 250 to 420 nm when the lithographic printing plate precursor is exposed imagewise with an ultraviolet laser. Sensitizing dyes that absorb the light are preferred. The infrared absorber is preferably a dye or pigment having an absorption maximum at a wavelength of 760 to 1200 nm. Such an infrared absorber can be appropriately selected from known ones.

Particularly preferred among these dyes are cyanine dyes, squarylium dyes, pyrylium salts, nickel thiolate complexes, and indolenine cyanine dyes. Furthermore, cyanine dyes and indolenine cyanine dyes are preferred.
These infrared absorbers are added in a proportion of 0.001 to 50% by mass, preferably 0.005 to 30% by mass, particularly preferably 0.01 to 10% by mass, based on the total solid content of the image recording layer. Can do. Within this range, high sensitivity can be obtained without adversely affecting the uniformity and film strength of the image recording layer.

Further, a sensitizing dye may be used, and the sensitizing dye used is a compound having absorption at a wavelength of 250 to 420 nm. Specific examples thereof include benzoin, benzoin methyl ether, benzoin ethyl ether, and 9-fluorenone. 2-chloro-9-fluorenone, 2-methyl-9-fluorenone, 9-anthrone, 2-bromo-9-anthrone, 2-ethyl-9-anthrone, 9,10-anthraquinone, 2-ethyl-9, 10 -Anthraquinone, 2-t-butyl-9,10-anthraquinone, 2,6-dichloro-9,10-anthraquinone, xanthone, 2-methylxanthone, 2-methoxyxanthone, thioxanthone, benzyl, dibenzalacetone, p- (Dimethylamino) phenylstyryl ketone, p- (dimethylamino) phenyl p Methyl styryl ketone, benzophenone, p- (dimethylamino) benzophenone (or Michler's ketone), p- (diethylamino) benzophenone, and the like benzanthrone.
These sensitizing dyes are preferably from 0.1 to 50% by mass, more preferably from 0.5 to 30% by mass, particularly preferably from 0.8 to 20% by mass, based on the total solid content constituting the image recording layer. Can be added.

[(B) Polymerization initiator]
A polymerization initiator is a compound that initiates and accelerates the polymerization of a compound having a polymerizable unsaturated group by generating radicals by energy of light, heat, or both. Examples of the polymerization initiator that can be used include a known thermal polymerization initiator, a compound having a bond with a small bond dissociation energy, and a photopolymerization initiator.
Examples of the polymerization initiator as described above include organic halogen compounds, carbonyl compounds, organic peroxides, azo polymerization initiators, azide compounds, metallocene compounds, hexaarylbiimidazole compounds, organic boron compounds, disulfone compounds, and oximes. Examples thereof include ester compounds, oxime ether compounds, and onium salt compounds.
The polymerization initiator used preferably has a maximum absorption wavelength of 400 nm or less. More preferably, the maximum absorption wavelength is 360 nm or less, and most preferably 300 nm or less. By making the absorption wavelength in the ultraviolet region in this way, the white light safety of the lithographic printing plate precursor is improved.
These polymerization initiators are added in a proportion of 0.1 to 50% by mass, preferably 0.5 to 30% by mass, particularly preferably 1 to 20% by mass, based on the total solid content constituting the image recording layer. Can do. Within this range, good sensitivity and good stain resistance of the non-image area during printing can be obtained. These polymerization initiators may be used alone or in combination of two or more. Moreover, these polymerization initiators may be added to the same layer as other components, or another layer may be provided and added thereto.

[(C) Polymerizable compound]
The polymerizable compound used in the image recording layer is an addition polymerizable compound having at least one ethylenically unsaturated double bond, and is selected from compounds having at least one terminal ethylenically unsaturated bond, preferably two or more. . Such a compound group is widely known in the industrial field, and these can be used without any particular limitation. These have chemical forms such as monomers, prepolymers, i.e. dimers, trimers and oligomers, or mixtures thereof and copolymers thereof. Examples of monomers and copolymers thereof include unsaturated carboxylic acids (for example, acrylic acid, methacrylic acid, itaconic acid, crotonic acid, isocrotonic acid, maleic acid, etc.), and esters and amides thereof. In this case, an ester of an unsaturated carboxylic acid and an aliphatic polyhydric alcohol compound, or an amide of an unsaturated carboxylic acid and an aliphatic polyvalent amine compound is used. In addition, an addition reaction product of an unsaturated carboxylic acid ester or amide having a nucleophilic substituent such as a hydroxyl group, amino group or mercapto group with a monofunctional or polyfunctional isocyanate or epoxy, and monofunctional or polyfunctional A dehydration condensation reaction product with a functional carboxylic acid is also preferably used. Further, an addition reaction product of an unsaturated carboxylic acid ester or amide having an electrophilic substituent such as an epoxy group or an epoxy group with a monofunctional or polyfunctional alcohol, amine or thiol, a halogen group or In addition, a substitution reaction product of an unsaturated carboxylic acid ester or amide having a leaving substituent such as a tosyloxy group and a monofunctional or polyfunctional alcohol, amine or thiol is also suitable. As another example, it is also possible to use a group of compounds substituted with unsaturated phosphonic acid, styrene, vinyl ether or the like instead of the unsaturated carboxylic acid.

About these polymerizable compounds, the details of usage such as the structure, single use or combination, addition amount, etc. can be arbitrarily set according to the performance design of the final lithographic printing plate precursor. For example, it is selected from the following viewpoints.
From the viewpoint of sensitivity, a structure having a large unsaturated group content per molecule is preferable, and in many cases, a bifunctional or higher functionality is preferable. Further, in order to increase the strength of the image portion, that is, the cured film, those having three or more functionalities are preferable, and further, different functional numbers and different polymerizable groups (for example, acrylic acid ester, methacrylic acid ester, styrene compound, vinyl ether type). A method of adjusting both sensitivity and strength by using a compound) is also effective.
In addition, the compatibility and dispersibility with other components in the image recording layer (for example, binder polymer, polymerization initiator, colorant, etc.), the selection and use method of the polymerizable compound is an important factor, For example, the compatibility may be improved by using a low-purity compound or using two or more kinds in combination. In addition, a specific structure may be selected for the purpose of improving the adhesion to the support or the oxygen barrier protective layer.
The polymerizable compound is used in the image recording layer in an amount of preferably 5 to 80% by mass, more preferably 25 to 75% by mass. These may be used alone or in combination of two or more. In addition, the usage of the polymerizable compound can be arbitrarily selected from the viewpoint of polymerization inhibition with respect to oxygen, resolution, fogging, refractive index change, surface adhesiveness, etc. The layer construction and coating method such as undercoating and overcoating can also be carried out.

[Other components of image recording layer]
In the image recording layer, components other than the above (A), (B), (C), for example, binder polymer, surfactant, colorant, print-out agent, polymerization inhibitor (thermal polymerization inhibitor), higher fatty acid Derivatives, plasticizers, inorganic fine particles, low molecular weight hydrophilic compounds and the like can be contained.
For example, as the binder polymer, a conventionally known one can be used without limitation, and a linear organic polymer having a film property is preferable. Examples of such binder polymers include acrylic resins, polyvinyl acetal resins, polyurethane resins, polyurea resins, polyimide resins, polyamide resins, epoxy resins, methacrylic resins, polystyrene resins, novolac phenolic resins, polyester resins, and synthetic rubbers. Natural rubber may be used. Binder polymers may be used alone or in admixture of two or more.
The content of the binder polymer is preferably 10 to 90% by mass and more preferably 20 to 80% by mass with respect to the total solid content of the image recording layer. Within this range, good image area strength and image formability can be obtained. Moreover, it is preferable to use a polymeric compound and a binder polymer in the quantity used as 1 / 9-7 / 3 by mass ratio.

In the image recording layer, a surfactant can be used in order to promote on-press developability at the start of printing and to improve the coated surface state. Examples of the surfactant include nonionic surfactants, anionic surfactants, cationic surfactants, amphoteric surfactants, and fluorosurfactants. Surfactant may be used independently and may be used in combination of 2 or more type.
Surfactant can be used individually or in combination of 2 or more types. The surfactant is preferably contained in the image recording layer in an amount of 0.001 to 10% by mass, and more preferably 0.01 to 5% by mass.

In the image recording layer, a dye having a large absorption in the visible light region can be used as an image colorant. Specifically, Oil Yellow # 101, Oil Yellow # 103, Oil Pink # 312, Oil Green BG, Oil Blue BOS, Oil Blue # 603, Oil Black BY, Oil Black BS, Oil Black T-505 (orientated chemistry) Kogyo Co., Ltd.), Victoria Pure Blue, Crystal Violet (CI42555), Methyl Violet (CI42535), Ethyl Violet, Rhodamine B (CI145170B), Malachite Green (CI42000), Methylene Blue (CI522015), etc. And dyes described in Japanese Patent No. 293247. Also, pigments such as phthalocyanine pigments, azo pigments, carbon black, titanium oxide, etc. can be suitably used.
These colorants are preferably added since it is easy to distinguish an image area from a non-image area after image formation. The amount added is preferably 0.01 to 10% by mass in the image recording layer.

  In the image recording layer, a compound that changes color by an acid or a radical can be added in order to generate a printout image. As such a compound, various dyes such as diphenylmethane, triphenylmethane, thiazine, oxazine, xanthene, anthraquinone, iminoquinone, azo, and azomethine are effectively used.

In order to prevent unnecessary thermal polymerization of the polymerizable compound (C) during production or storage of the image recording layer, it is preferable to add a small amount of a thermal polymerization inhibitor to the image recording layer.
Examples of the thermal polymerization inhibitor include hydroquinone, p-methoxyphenol, di-t-butyl-p-cresol, pyrogallol, t-butylcatechol, benzoquinone, 4,4′-thiobis (3-methyl-6-t- (Butylphenol), 2,2'-methylenebis (4-methyl-6-tert-butylphenol), N-nitroso-N-phenylhydroxylamine aluminum salt are preferred.
The thermal polymerization inhibitor is preferably contained in the image recording layer in an amount of about 0.01 to about 5% by mass.

  In order to prevent polymerization inhibition by oxygen, a higher fatty acid derivative such as behenic acid or behenic acid amide is added to the image recording layer, and it is unevenly distributed on the surface of the image recording layer in the drying process after coating. Also good. The amount of the higher fatty acid derivative added is preferably about 0.1 to about 10% by mass with respect to the total solid content of the image recording layer.

The image recording layer is formed by dispersing or dissolving the above-described constituents in an appropriate solvent to prepare a coating solution and coating it.
The image recording layer can be formed by preparing a plurality of coating solutions in which the same or different components are dispersed or dissolved in the same or different solvents, and repeating a plurality of coatings and dryings.
The image recording layer coating amount (solid content) is preferably 0.3 to 1.5 g / m ² , and preferably 0.5 to 1.5.
g / m ² is more preferable.
Various methods can be used as the coating method. Examples thereof include bar coater coating, spin coating, spray coating, curtain coating, dip coating, air knife coating, blade coating, and roll coating.

The support used for the lithographic printing plate precursor is not particularly limited as long as it is a dimensionally stable plate. For example, paper, paper laminated with plastic (eg, polyethylene, polypropylene, polystyrene, etc.), metal plate (eg, aluminum, zinc, copper, etc.), plastic film (eg, cellulose diacetate, cellulose triacetate, cellulose propionate) Cellulose butyrate, cellulose acetate butyrate, cellulose nitrate, polyethylene terephthalate, polyethylene, polystyrene, polypropylene, polycarbonate, polyvinyl acetal, etc.), and paper or plastic films on which the above-mentioned metals are laminated or deposited. Preferable supports include a polyester film and an aluminum plate. Among these, an aluminum plate that has good dimensional stability and is relatively inexpensive is preferable.
The lithographic printing plate precursor may be further provided with a back coat or an undercoat layer.

[Prepress, print]
In the lithographic printing method of the present invention, the lithographic printing plate precursor as described above is exposed imagewise by exposure through a transparent original having a line image, a halftone dot image or the like, or by laser scanning exposure with digital data. Examples of the exposure light source include a carbon arc, a high-pressure mercury lamp, a xenon lamp, a metal halide lamp, a fluorescent lamp, a tungsten lamp, a halogen lamp, an ultraviolet light laser, a visible light laser, and an infrared light laser. A laser is particularly preferable, and examples thereof include a solid-state laser and a semiconductor laser that emit infrared light of 760 to 1200 nm, and a semiconductor laser that emits light of 250 to 420 nm. When a laser is used, scanning exposure is preferably performed in an image-like manner according to digital data. In order to shorten the exposure time, it is preferable to use a multi-beam laser device.

In the lithographic printing method of the present invention, the method of using the fountain solution is not particularly limited. After exposing the lithographic printing plate precursor as described above, the unnecessary image recording layer is dissolved and removed with a suitable developer, and then the fountain solution prepared from the oil-based ink and the fountain solution composition of the present invention is applied to the plate surface. Can be supplied and printed.
Further, in the lithographic printing method of the present invention, the lithographic printing plate precursor as described above is imagewise exposed with a laser beam, and then the oil-based ink and the fountain solution composition of the present invention are passed through no development processing step. The fountain solution prepared from the above can be supplied for printing. That is, the fountain solution composition of the present invention can be used in a so-called on-press development method in which a non-image portion is removed on a printing machine during a printing process to obtain a lithographic printing plate.
Specifically, after exposing a lithographic printing plate precursor with a laser beam, a method of mounting and printing on a printing machine without passing through a development processing step, after mounting a lithographic printing plate precursor on a printing machine, Examples include a method of performing exposure with laser light and printing without going through a development processing step.

After exposing the lithographic printing plate precursor imagewise with a laser beam and supplying it with dampening water and oil-based ink without passing through a development process such as a wet development process, the exposed part of the image recording layer The image recording layer cured by exposure forms an oil-based ink receiving portion having an oleophilic surface. On the other hand, in the unexposed area, the uncured image recording layer is dissolved or dispersed and removed by the supplied dampening water and / or oil-based ink, and a hydrophilic surface is exposed in that area. As a result, the fountain solution component adheres to the exposed hydrophilic surface, and the oil-based ink is deposited on the image recording layer in the exposed area, and printing is started. Here, dampening water or oil-based ink may be supplied to the printing plate first, but the dampening water is first oil-based in order to prevent the dampening water from being contaminated by the image recording layer in the unexposed area. It is preferable to supply ink.
In this way, the lithographic printing plate precursor is subjected to on-press development on an offset printing machine and used as it is for printing a large number of sheets.

Next, the present invention will be described more specifically with reference to examples. % Indicates mass% unless otherwise specified.
Various fountain solution compositions of Examples 1 to 4 and Comparative Examples 1 and 2 were prepared according to the composition of Table 1 below. In the table, the unit is gram, and water is finally added to make 1000 mL. These are all concentrated types and are diluted at the time of use.
The compositions of Examples 1 to 4 and Comparative Examples 1 and 2 prepared as described above were each diluted 40 times with pseudo-hard water having a hardness of 400 ppm, and the pH became around 4.8 to 5.3. Thus, it was adjusted with KOH or ammonia water to obtain a dampening solution that was actually used.
Further, Comparative Example 3 was prepared as a working solution by adding 8% isopropyl alcohol and 1% dampening water “EU-3” manufactured by Fuji Photo Film Co., Ltd. to pseudo-hard water having a hardness of 400 ppm.

^*プルロニックL31＝ポリオキシエチレンポリオキシプロピレンブロックポリマー（アデカ）

^* Pluronic L31 = polyoxyethylene polyoxypropylene block polymer (ADEKA)

[Test method]
The printing machine uses Heidel MOV (Alcolor Water Supply System), Toyo Ink Co., Ltd.'s environmentally friendly NonVOC ink name, High Echo NV-100 Unity process red ink, and Fuji Photo Film Co., Ltd. Thermally untreated CT-P plate Eco & Free System “ET-S” was used. This plate is a photopolymerization type lithographic printing plate precursor in which an image recording layer containing an actinic ray absorber, a polymerization initiator and a polymerizable compound and an oxygen-blocking protective layer provided thereon are provided. This plate was baked with an image of the TAFFTA20 FM screen using the thermal laser setter CREO Quantum, then attached to the printing press, supplied with various dampening water and ink, and completed on-machine development. A print test was conducted.

(a) Continuous printing stability:
Obtain the amount of dampening water that does not cause stains and does not cause water loss (minimum water raising amount), and perform printing using various dampening waters with the minimum amount of water rising, causing the printed matter to become dirty or lose water. Thus, the determination is made based on the number of printed sheets until a satisfactory printed matter cannot be obtained.
10,000 sheets or more A
9999-3000 sheets B
2999-1 sheets C
None D

(b) Emulsification:
The state of emulsification of the ink on the ink kneading roller when 10,000 sheets are printed is examined.
Good A
Slightly bad B
Bad C
(c) ink density stability on printed matter;
Printing was performed up to 10,000 sheets, and the halftone dot density of the printed material was measured.
It was evaluated whether the halftone dot density after printing 10,000 sheets would be reduced by imperfection compared with the density of printing.
No change in halftone dot density (concentration reduction rate less than 5%) A
Halftone dot density change (density reduction rate less than 5% to less than 10%) B
Halftone dot change (concentration reduction rate of 10% or more) C
The results are shown in Table 2.

  From the above results, the fountain solution according to the examples of the present invention is excellent in all of the continuous printing stability, the emulsifying property, and the ink density stability on the printed matter. Not only a good printed product similar to water was obtained, but also after printing a large number of sheets from the start of printing, the halftone dot density of the printed product is stable, which is preferable in terms of quality. Further, unlike the isopropyl alcohol, the fountain solution compositions of Examples 1 to 4 have no occupational safety problems and reduced fire safety problems, which is very preferable in terms of the working environment.

Claims (3)

A dampening for lithographic printing comprising an organic solvent having a boiling point of 150 ° C. or higher at 20 ° C. and at least one compound selected from the following formula (III): Water composition.

Wherein R ^{1 to} R ⁴ each independently represents an alkyl group having 1 to 12 carbon atoms, a benzyl group, or a phenyl group, Z represents N, P or B, X represents a counter ion, Z When X is N or P, X represents an anion, and when Z is B, X represents a cation.)   The fountain solution prepared from the fountain solution composition according to claim 1 is supplied to the lithographic printing plate obtained by making a plate from a photopolymerization lithographic printing plate precursor provided with an oxygen barrier protective layer. Including lithographic printing.   After exposing the photopolymerization type lithographic printing plate precursor provided with the oxygen barrier protective layer, the fountain solution prepared from the fountain solution composition according to claim 1 is supplied to the plate surface, and the image recording layer is not exposed. A lithographic printing method comprising removing parts.