JP2006181854A - Concentrated composition of dampening water for lithographic printing plate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a concentrated composition of dampening water which can be substituted for an isopropyl alcohol-based one and is agreeable and safe in terms of working environment and excellent in printing stability, and the concentrated composition of the dampening water for a lithographic printing plate which exhibits excellent and stable printability even under the conditions of a member rotating at a high speed and excels in shelf stability though it is concentrated. <P>SOLUTION: The concentrated composition of the dampening water for the lithographic printing plate contains 1 to less than 20 mass% of polypropylene glycol having a molecular weight of 200-1,000 and contains 5 to less than 40 mass% of propylene glycol mono n-butyl ether or 5 to less than 40 mass% of propylene glycol monomethyl ether. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a fountain solution concentrate composition for lithographic printing plates, and more specifically to a fountain solution concentrate composition for lithographic printing plates that provides a fountain solution composition useful for offset printing of lithographic printing plates. .

  Lithographic printing is a printing method that skillfully uses the property that water and oil do not essentially mix, and the printing plate surface consists of an area that receives water and repels oil-based ink, and an area that repels water and receives oil-based ink. Thus, the former is a non-image area and the latter is an image area. The non-image area is moistened with the 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. Made. Conventionally known fountain solutions include alkali metal salts or ammonium salts of dichromic acid, phosphoric acid or salts thereof such as colloidal substances such as ammonium salts, gum arabic, and carboxymethyl cellulose (CMC). There is an aqueous solution added. However, the fountain solution containing only these compounds has the disadvantage that it is difficult to uniformly wet the non-image area of the plate, so that the printed matter sometimes gets soiled, and considerable skill is required to adjust the supply amount of the fountain solution. It has become a problem such as requiring. In recent years, regulations on the release of chromium ions in wastewater have become stricter and tend to be regulated from the aspect of health and safety.

In order to remedy this drawback, a Dahlglen system has been proposed in which an aqueous solution containing about 20 to 25% of isopropyl alcohol is used as a fountain solution. According to this method, the wetness to the non-image area is improved, the amount of dampening water can be reduced, the balance of the supply amount of printing ink and water can be easily adjusted, and dampening water into the printing ink can be obtained. There are a number of advantages in terms of workability and accuracy of the obtained printed matter, such as a reduced emulsification amount and improved transferability of printing ink to the blanket. However, since this isopropyl alcohol is easy to evaporate, a special device for keeping the isopropyl alcohol concentration of the dampening solution constant is necessary, which is expensive in terms of price. In addition, because isopropyl alcohol has a peculiar unpleasant odor and falls under the category of dangerous substances, Class 4 alcohols, it is not only necessary to pay close attention to fire. Since it is a two-type organic solvent and is usually about 5 to 20% by mass when used as a fountain solution, it may be necessary to take measures for purification of the working environment.
Further, from the viewpoint of energy saving, it is required to supply the fountain solution as thick as possible as a concentrated solution to save transportation and storage costs. However, when the concentration of the concentrate is increased, there are problems such as precipitation due to poor solubility and deterioration of performance due to storage in the concentrate.

In recent years, fountain solutions using ethylene glycol ether or propylene glycol ether have been proposed as organic solvents that replace isopropyl alcohol (see, for example, Patent Documents 1 to 3). However, these prior art documents do not describe preferable concentration ranges of various solvents when preparing dampening water as a concentrate.
Therefore, it is safe in terms of environmental hygiene, does not require specialized skills in printing operations, is low in transportation costs, can be stored in a small space, has little deterioration due to preservation, and is free from stains on the printing plate. There is a need for a fountain solution concentrate for a lithographic printing plate that can not only prevent, but also obtain a high-quality print having excellent fountain solution characteristics such as being compatible with high-speed printing.

JP 51-72507 A Japanese Patent Laid-Open No. 5-221180 Japanese Patent Laid-Open No. 3-90389

  An object of the present invention is to provide a fountain solution concentration composition that is comfortable and safe in a working environment that can replace isopropyl alcohol, and that has excellent printing stability. Another object of the present invention is to provide a fountain solution concentrated composition for a lithographic printing plate that exhibits good and stable printability even under the condition of a member rotating at a high speed, and has a good storage stability while being concentrated. There is.

The inventors of the present invention have studied the fountain solution concentrate for lithographic printing plates in order to achieve the above-mentioned problems. As a result, the inventors have included polypropylene glycol having a molecular weight of 200 to 1000 in a predetermined amount range, Concentrated fountain solution containing n-butyl ether or propylene glycol monomethyl ether in a predetermined range, and the stability of the concentrated liquid and excellent printing performance when diluted and used in a printing press I found out.
Therefore, the present invention contains 1 to 20% by weight of polypropylene glycol having a molecular weight of 200 to 1000, and 5 to 40% by weight of propylene glycol mono n-butyl ether or 5% by weight or more of propylene glycol monomethyl ether. A fountain solution concentrated composition for lithographic printing plates, comprising less than 40% by mass.
In a preferred embodiment of the present invention, the fountain solution concentrated composition contains 0.05 to 1.0 mol / liter of at least one selected from organic acids, inorganic acids and salts thereof. In another preferred embodiment of the present invention, 0.05 to 3.0% by mass of at least one selected from a bromonitroalcohol compound and a 1,2-benzisothiazolin-3-one compound is contained.

  The fountain solution concentrated composition for lithographic printing plates of the present invention does not require isopropyl alcohol, and is therefore comfortable and highly safe in the working environment. The fountain solution concentrate composition for lithographic printing plates of the present invention has little change in performance even when stored over time. The fountain solution concentrate composition of the present invention can exhibit good wettability on the roller and on the plate surface even under the condition of a member that rotates at a high speed when diluted and used. Can be obtained. Because it can be used stably for a long time, it also leads to an improvement in productivity.

Hereinafter, the fountain solution concentrated composition for lithographic printing plates of the present invention will be described in detail.
In addition, the fountain solution concentrated composition of the present invention is used after diluting the concentrate to about 20 to 100 times when used. In the present specification, the contents and addition amounts of various components mentioned below are based on the total mass of the concentrated composition unless otherwise specified.
The fountain solution concentrated composition for lithographic printing plates of the present invention contains 1 to 20% by mass of polypropylene glycol having a molecular weight of 200 to 1000. When the amount of the polypropylene glycol having a molecular weight of 200 to 1000 is within this range, it is appropriate from the viewpoint of the stability of the concentrated solution and the effect of preventing smudges during printing.
In the fountain solution concentrated composition of the present invention, the preferable content of polypropylene glycol having a molecular weight of 200 to 1000 is 3% by mass or more and less than 15% by mass.

The fountain solution concentrated composition for lithographic printing plates of the present invention also contains propylene glycol mono-n-butyl ether in a range of 5% by mass to less than 40% by mass, or propylene glycol monomethyl ether in a range of 5% by mass to less than 40% by mass. . When the amount of propylene glycol mono n-butyl ether or propylene glycol monomethyl ether is within this range, it is appropriate from the viewpoint of the stability of the concentrated liquid and the antifouling effect during printing.
In the fountain solution concentrated composition of the present invention, the preferred content of propylene glycol mono n-butyl ether is 10% by mass or more and less than 35% by mass, and the preferred content of propylene glycol monomethyl ether is 10% by mass or more and less than 35% by mass. It is.
The total amount of polypropylene glycol having a molecular weight of 200 to 1000 and propylene glycol mono n-butyl ether or propylene glycol monomethyl ether is suitably 50% by mass or less, preferably 45% by mass or less, more preferably 40% by mass or less. It is.

In addition, the following can be contained in the fountain solution concentrated composition of the present invention.
(a) Auxiliary agent for improving wettability
(b) Water-soluble polymer compound
(c) pH adjuster
(d) Odor masking agent
(e) Others ((i) preservatives, (ii) chelating agents, (iii) colorants, (iv) rust inhibitors, (v) antifoaming agents, etc.)

  (a) A surfactant or other solvent can be used as an aid for improving wettability. Among the surfactants, 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. Acid salts, alkylnaphthalene sulfonates, alkylphenoxy polyoxyethylenepropyl sulfonates, polyoxyethylene alkylsulfenyl ether salts, N-methyl-N-oleyl taurine sodium salts, N-alkylsulfosuccinic acid monoamide disodium salts, Petroleum sulfonates, sulfated castor oil, sulfated beef tallow oil, sulfate esters of fatty acid alkyl esters, alkyl sulfate esters, polyoxyethylene alkyl ether sulfate esters, fatty acids Noglyceride sulfates, polyoxyethylene alkylphenyl ether sulfates, polyoxyethylene styryl phenyl ether sulfates, alkyl phosphates, polyoxyethylene alkyl ether phosphates, polyoxyethylene alkylphenyl ether phosphates, styrene -Partially saponified products of maleic anhydride copolymer, partial saponified products of olefin-maleic anhydride copolymer, naphthalene sulfonate formalin condensate and the like. Among these, dialkyl sulfosuccinates, alkyl sulfates and alkyl naphthalene sulfonates are particularly preferably used.

Nonionic surfactants include polyoxyethylene alkyl ethers, polyoxyethylene alkyl phenyl ethers, polyoxyethylene polystyryl phenyl ethers, polyoxyethylene polyoxypropylene alkyl ethers, glycerin fatty acid partial esters, sorbitan Fatty acid partial esters, pentaerythritol fatty acid partial esters, propylene glycol mono fatty acid esters, sucrose fatty acid partial esters, polyoxyethylene sorbitan fatty acid partial esters, polyoxyethylene sorbitol fatty acid partial esters, polyethylene glycol fatty acid esters, poly Glycerin fatty acid partial esters, polyoxyethylenated castor oil, polyoxyethylene glycerin fatty acid partial esters, fatty acid die Examples include olamides, N, N-bis-2-hydroxyalkylamines, polyoxyethylene alkylamines, triethanolamine fatty acid esters, polyoxyethylene-polyoxypropylene block polymers, and trialkylamine oxides. . In addition, fluorine-based surfactants and silicon-based surfactants can also be used.
When a surfactant is used, the content thereof is 10% by mass or less, preferably 0.1 to 5% by mass in consideration of foaming. Two or more of these surfactants can be used in combination.

Other auxiliaries include ethylene glycol monomethyl ether, diethylene glycol monomethyl ether, triethylene glycol monomethyl ether, tetraethylene glycol monomethyl ether, ethylene glycol monoethyl ether, diethylene glycol monoethyl ether, triethylene glycol monoethyl ether, tetraethylene glycol mono Ethyl ether, ethylene glycol monopropyl ether, diethylene glycol monopropyl ether, triethylene glycol monopropyl ether, tetraethylene glycol monopropyl ether, ethylene glycol monoisopropyl ether, diethylene glycol monoisopropyl ether, triethylene glycol monoisopropyl ether, Tetra Chi Ren glycol monoisopropyl ether,
Ethylene glycol monobutyl ether, diethylene glycol monobutyl ether, triethylene glycol monobutyl ether, tetraethylene glycol monobutyl ether, ethylene glycol monoisobutyl ether, diethylene glycol monoisobutyl ether, triethylene glycol monoisobutyl ether, tetraethylene glycol monoisobutyl ether, ethylene glycol monotertiary Ributyl ether, diethylene glycol monotertiary butyl ether, triethylene glycol monotertiary butyl ether, tetraethylene glycol monotertiary butyl ether,

  Dipropylene glycol monomethyl ether, tripropylene glycol monomethyl ether, tetrapropylene glycol monomethyl ether, propylene glycol monoethyl ether, dipropylene glycol monoethyl ether, tripropylene glycol monoethyl ether, tetrapropylene glycol monoethyl ether, propylene glycol monopropyl ether , Dipropylene glycol monopropyl ether, tripropylene glycol monopropyl ether, tetrapropylene glycol monopropyl ether, propylene glycol monoisopropyl ether, dipropylene glycol monoisopropyl ether, tripropylene glycol monoisopropyl ether, tetrapropylene glycol monoisopropyl Ether, dipropylene glycol monobutyl ether, tripropylene glycol monobutyl ether, tetrapropylene glycol monobutyl ether, propylene glycol monoisobutyl ether, dipropylene glycol monoisobutyl ether, tripropylene glycol monoisobutyl ether, tetrapropylene glycol monoisobutyl ether, propylene glycol mono Tertiary butyl ether, dipropylene glycol monotertiary butyl ether, tripropylene glycol monotertiary butyl ether, tetrapropylene glycol monotertiary butyl ether, monomethyl ether, monoethyl ether, monopropyl ether, monoisopropylene of polypropylene glycol having a molecular weight of 200 to 1000 Ropirueteru and mono-butyl ether,

Propylene glycol, dipropylene glycol, tripropylene glycol, tetrapropylene glycol and pentapropylene glycol, ethylene glycol, diethylene glycol, triethylene glycol, butylene glycol, hexylene glycol, 2-ethyl-1,3-hexanediol, 3-methoxy- 3-methyl-1-butanol, 1-butoxy-2-propanol, glycerin, diglycerin, polyglycerin, trimethylolpropane, 2-pyrrolidone derivatives substituted at the 1-position with an alkyl group having 1 to 8 carbon atoms, etc. Is mentioned. Among these, glycerin and the above-mentioned 2-pyrrolidone derivative are particularly preferable. In the 2-pyrrolidone derivative, the alkyl group having 1 to 8 carbon atoms at the 1-position may be linear or branched.
These solvents may be used alone or in combination of two or more. In general, these solvents are suitably used in the range of 1 to 30% by mass, preferably 2 to 20% by mass, based on the total mass of the fountain solution concentrated composition.

  Examples of the water-soluble polymer compound (b) used in the fountain solution concentrated composition of the present invention include gum arabic, starch derivatives (eg, dextrin, enzymatically degraded dextrin, hydroxypropylated enzymatically degraded dextrin, carboxymethylated starch, Phosphoric acid starch, octenyl succinylated starch), alginate, fibrin derivatives (for example, carboxymethylcellulose, carboxyethylcellulose, methylcellulose, hydroxyethylcellulose) and other natural products and their modified products, polyethylene glycol and its copolymers, polyvinyl alcohol and its Derivatives, polyacrylamide and copolymers thereof, polyacrylic acid and copolymers thereof, vinyl methyl ether / maleic anhydride copolymers, vinyl acetate / maleic anhydride copolymers, polystyrene sulfonic acids and copolymers thereof Synthesis of polymer, polyvinylpyrrolidone, and the like. Among these, carboxymethyl cellulose and hydroxyethyl cellulose are particularly preferable. The content of the water-soluble polymer compound is suitably from 0.01 to 10% by mass, more preferably from 0.05 to 5% by mass, based on the fountain solution concentrated composition.

  As the (c) pH adjuster used in the fountain solution concentrated composition of the present invention, at least one selected from water-soluble organic acids, inorganic acids and salts thereof can be used. These compounds are effective in adjusting the pH of the fountain solution or buffering the pH, and appropriate etching or anticorrosion of the lithographic printing plate support. Preferred organic acids include, for example, citric acid, ascorbic acid, malic acid, tartaric acid, lactic acid, acetic acid, gluconic acid, hydroxyacetic acid, succinic acid, malonic acid, levulinic acid, sulfanilic acid, p-toluenesulfonic acid, phytic acid, and organic phosphones. An acid etc. are mentioned. 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, and one of these organic acids, inorganic acids and salts thereof is used alone. Or you may use it as a mixture of 2 or more types. The addition amount of these pH adjusting agents to the fountain solution concentrated composition of the present invention is preferably in the range of 0.05 mol / liter to 1.0 mol / liter in combination of organic acid, inorganic acid and salts thereof. If it is less than 0.05 mol / liter, the etching force of aluminum, which is a support for a lithographic printing plate, is insufficient, and stains during printing tend to be somewhat worse. On the other hand, if it exceeds 1.0 mol / liter, the printing press is rusted, the solubility in the fountain solution concentrate tends to be insufficient, and there is a concern about the stability of the concentrate. The pH value of the fountain solution concentrated composition is preferably used in an acidic region in the range of 3 to 7, but contains alkali metal hydroxide, phosphoric acid, alkali metal salt, alkali metal carbonate, silicate, etc. It can also be used in the alkaline region of pH 7-11.

(d) Odor masking agents include esters that are conventionally known for use as perfumes. For example, there is one represented by the following general formula (I).
R ₁ COOR ₂ (I)
In the compound of the general formula (I), R ₁ is an alkyl group having 1 to 15 carbon atoms, an alkenyl group, an aralkyl group, or a phenyl group. In the case of an alkyl group or an alkenyl group, the number of carbon atoms is preferably 4-8. When R ₁ represents an alkyl group, an alkenyl group or an aralkyl group, they may be linear or branched. An alkenyl group having one double bond is particularly suitable. Examples of the aralkyl group include a benzyl group and a phenylethyl group. One or more hydrogen atoms of the alkyl group, alkenyl group, aralkyl group, or phenyl group represented by R ₁ may be substituted with a hydroxyl group or an acetyl group. R ₂ is an alkyl group having 3 to 10 carbon atoms, an aralkyl group, or a phenyl group, which may be linear or branched. In the case of an alkyl group, the number of carbon atoms is preferably 3-9. Examples of the aralkyl group include a benzyl group and a phenylethyl group.

  Specific examples of (d) odor masking agents that can be used include formic acid, acetic acid, propionic acid, butyric acid, isobutyric acid, 2-ethylbutyric acid, valeric acid, isovaleric acid, 2-methylvaleric acid, hexanoic acid (caproic acid), 4-methylpentanoic acid (isohexanoic acid), 2-hexenoic acid, 4-pentenoic acid, heptanoic acid, 2-methylheptanoic acid, octanoic acid (caprylic acid), nonanoic acid, decanoic acid (capric acid), 2-decenoic acid , Esters of lauric acid or myristic acid. In addition, there are acetoacetate esters such as benzyl phenylacetate, ethyl acetoacetate and 2-hexyl acetoacetate. Among them, preferred are n-pentyl acetate, isopentyl acetate, n-butyl butyrate, n-pentyl butyrate and isopentyl butyrate, and n-butyl butyrate, n-pentyl butyrate and isopentyl butyrate are particularly preferable. The content of the odor masking agent (d) in the fountain solution concentrated composition is suitably 0.01 to 10% by weight, more preferably 0.1 to 10% by weight based on the total weight of the fountain solution concentrated composition. 5% by mass. By using these, the work environment can be further improved. Also. Vanillin, ethyl vanillin or the like may be used in combination.

  (E) (i) Preservative used in the fountain solution concentrated composition of the present invention includes phenol or a derivative thereof, formalin, imidazole derivative, sodium dehydroacetate, 4-isothiazolin-3-one derivative, benztriazole derivative, Amidine or guanidine derivatives, quaternary ammonium salts, pyridine, quinoline or guanidine derivatives, diazine or triazole derivatives, oxazole or oxazine derivatives, bromonitroalcohol compounds, 1,2-benzisothiazolin-3-one compounds, etc. Is mentioned. These preferable addition amounts are amounts that stably exert effects on bacteria, molds, yeasts, etc., and differ depending on the types of bacteria, molds, yeasts, etc., but are 0. The range of 01-10 mass% is preferable, and it is preferable to use together 2 or more types of preservatives which are effective with respect to various molds, bacteria, and yeasts. Among these, it is particularly preferable to contain 0.05 to 3.0% by mass of at least one selected from bromonitroalcohol compounds and 1,2-benzisothiazolin-3-one compounds.

  Examples of the bromonitroalcohol compound include compounds represented by the following general formulas [A] to [C].

（式中、Ｒ₁〜Ｒ₁₃はそれぞれ独立に水素原子又はアルキル基を表す。）

(In the formula, R _{1 to} R ₁₃ each independently represents a hydrogen atom or an alkyl group.)

When R _{1 to} R ₁₃ in the general formulas [A] to [C] represent an alkyl group, a lower alkyl group is preferable, particularly an alkyl group having 1 to 3 carbon atoms such as a methyl group, an ethyl group, a propyl group, An isopropyl group or the like is suitable. One or more of these bromonitroalcohol compounds can be used.
Among the bromonitroalcohol compounds used in the present invention, particularly preferred are 2-bromo-2-nitropropane-1,3-diol (pronopol), 1,1-dibromo-1-nitro-2-ethanol (DBNE). ), 1,1-dibromo-1-nitro-2-propanol (DBNP), 3-bromo-3-nitropentane-2,4-diol, and the like.

Examples of the 1,2-benzisothiazolin-3-one compound include those represented by the following formula.

（式中、Ｒは水素原子又はアルキル基を表し、Ｘはアルキル基、アルコキシ基、又はハロゲン原子を表し、ｎは０又は１〜４の整数を表す。）
上記式中、Ｒがアルキル基を表すとき、低級アルキル基が好ましく、具体的に炭素原子数１〜４のアルキル基が好ましく、特にメチル基が挙げられる。Ｘがアルキル基を表すとき、低級アルキル基が好ましく、具体的に炭素原子数１〜４のアルキル基が好ましい。Ｘがアルコキシ基を表すとき、炭素原子数１〜４のアルコキシ基が好ましい。Ｘがハロゲン原子を表すとき、塩素原子、臭素原子が好ましい。
上記式で表される中でも、ｎ＝０、及びＲがメチル基であるものが好ましい。

(In the formula, R represents a hydrogen atom or an alkyl group, X represents an alkyl group, an alkoxy group, or a halogen atom, and n represents 0 or an integer of 1 to 4).
In the above formula, when R represents an alkyl group, a lower alkyl group is preferred, specifically an alkyl group having 1 to 4 carbon atoms, and particularly a methyl group. When X represents an alkyl group, a lower alkyl group is preferable, and an alkyl group having 1 to 4 carbon atoms is particularly preferable. When X represents an alkoxy group, an alkoxy group having 1 to 4 carbon atoms is preferable. When X represents a halogen atom, a chlorine atom or a bromine atom is preferable.
Among those represented by the above formula, those in which n = 0 and R is a methyl group are preferable.

  (E) (ii) a chelating agent can be further added to the fountain solution concentrated composition of the present invention. The fountain solution concentrate composition is usually prepared by diluting with tap water or well water at the time of use. At this time, calcium ions contained in the diluted tap water or well water have an adverse effect on printing. And may cause the printed matter to become dirty easily. In such a case, the above disadvantages can be eliminated by adding a chelating agent. Preferred chelating agents include, for example, ethylenediaminetetraacetic acid, its potassium salt, its sodium salt; diethylenetriaminepentaacetic acid, its potassium salt, sodium salt; triethylenetetraminehexaacetic acid, its potassium salt, its sodium salt, hydroxyethylethylenediaminetriacetic acid Nitrilotriacetic acid, sodium salt; 1-hydroxyethane-1,1-diphosphonic acid, potassium salt, sodium salt; aminotri (methylenephosphonic acid), potassium salt, sodium salt And organic phosphonic acids and phosphonoalkanetricarboxylic acids. Instead of the sodium salt or potassium salt of the chelating agent, an organic amine salt is also effective. These chelating agents are selected so that they are stably present in the fountain solution concentrated composition and do not inhibit the printability. The content of the chelate compound in the fountain solution concentrated composition is suitably 0.01 to 10% by mass, preferably 0.05 to 5% by mass.

  As the colorant (e) (iii) used in the fountain solution concentrated composition of the present invention, a food colorant can be preferably used. 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 (e) (iv) rust inhibitor used in the fountain solution concentrated composition of the present invention include benzotriazole, 5-methylbenzotriazole, thiosalicylic acid, benzimidazole and derivatives thereof. As the antifoaming agent (e) (v) used in the fountain solution concentrated composition of the present invention, a silicon antifoaming agent is preferable, and any of an emulsified dispersion type and a solubilized type can be used.

  The balance is water as a component of the fountain solution concentrate composition of the present invention. The fountain solution concentrated composition is diluted about 20 to 100 times with tap water, well water, etc. during normal use to obtain a fountain solution composition during use.

Next, the present invention will be described more specifically with reference to examples and comparative examples. % Indicates mass% unless otherwise specified.
According to the composition of the following Tables 1-3, the various fountain solution concentration compositions of Comparative Examples 1-13 and Examples 1-14 were prepared. The balance of the composition was water and finally made up to 1 liter. The unit of the content of each component in the composition is mol / liter for primary ammonium phosphate, ammonium nitrate, secondary ammonium citrate and the total of these, and the others are mass%.
The concentrated composition prepared here is diluted at the time of use to obtain a fountain solution composition.

  The storage stability was evaluated by storing the concentrates prepared with the compositions shown in Tables 1 to 3 at 50 ° C. for 1 week. Further, the printing stability width and the stability of the water supply roller were also evaluated using the fountain solution concentrated composition stored at room temperature of 25 ° C. In the printing test experiment, each concentrated composition was diluted 50 times with tap water and adjusted with NaOH / phosphoric acid (85%) so that the pH was around 4.8 to 5.3. The fountain solution composition actually used was subjected to a printing test. The printing machine uses Heidel Speed Master SM102 (Heidelberg Co., Ltd. sheet-fed offset printing machine, Alcolor water supply device), VALUES-G Beni (Dainippon Ink Chemical Co., Ltd.) ink, and Fuji Photo as the plate used. The following printing test was carried out using a plate made of HP-S manufactured by Film Co., Ltd. under standard conditions. The results are also shown in Tables 1 to 3 below.

(a) Storage stability of the concentrated composition 18 liters of the concentrated solution is sealed in a polyethylene container, and after storage at 50 ° C. for 1 week, 1 liter is collected from the upper part of the container, and tap water is added to this to add 50 liters. Diluted twice, prepared to a concentration of 2%, and used for printing test. The environmental temperature and humidity of the printing room was set to 35 ° C. and 50%, and printing stains in a high temperature environment were evaluated. The water scale at the time of printing was lowered, and the value of the water scale at which stains started to appear on the non-image portion of the printed matter was examined. Separately from this, the same test was performed on the fountain solution concentrated composition stored at room temperature of 25 ° C., and the value of the water scale on which dirt was generated was examined. In this test, the liquid diluted from the concentrated composition stored at 50 ° C. for 1 week has a higher water scale than the liquid diluted from the concentrated composition stored at room temperature of 25 ° C. Start to get dirty. Therefore, a water scale value that causes smearing during printing in a solution diluted from a concentrated composition stored at 50 ° C. for 1 week, and a stain in a liquid diluted from a fountain solution concentrated composition stored at room temperature of 25 ° C. The difference from the water scale value at which water is generated was determined, and it was determined that the smaller the difference, the better the storage stability of the concentrated composition.
○ …… Difference is less than 5 scales △ ...... Difference is 6 to 10
× …… The difference is 11 or more

(b) Printing stability width Tap water was added to the concentrated composition stored at room temperature of 25 ° C. to dilute it 50 times to prepare a concentration of 2% and used for the printing test. In the water supply scales 1 to 100 of the printing press (which is also a measure of the number of rotations of the water supply roller), the printable width was observed. If the water supply scale is reduced, the printed matter is likely to be stained, and if the water supply scale is increased, the ink density of the printed matter is lowered. A wider water supply scale is preferable.
○ …… 60-100
△ 70-100
× ... 80-100

(c) Water supply roller stability Tap water was added to the concentrated composition stored at room temperature of 25 ° C., diluted 50 times, and using dampening water prepared to a concentration of 2%, 10, 000 sheets were printed for 3 consecutive days. Dirt on the water supply roller on the first day (after printing 10,000 sheets), the second day (after printing 20,000 sheets), and the third day (after printing 30,000 sheets) (whether the water film can be uniformly cleaned on the rollers) How).
○ …… There is almost no dirt △ …… Some dirt is seen × …… Stains

  From the results of Tables 1 to 3, the fountain solution concentrated composition according to the present invention is excellent for any test items when diluted and used, and a good printed matter is obtained. It was found that the stability was also excellent.

Claims (5)

  1 to 20% by mass of polypropylene glycol having a molecular weight of 200 to 1000, and 5 to 40% by mass of propylene glycol mono n-butyl ether or 5 to 40% by mass of propylene glycol monomethyl ether A fountain solution concentrated composition for a lithographic printing plate, comprising:   The fountain solution concentrated composition for lithographic printing plates according to claim 1, comprising a polypropylene glycol having a molecular weight of 200 to 1000 in an amount of 3% by mass to less than 15% by mass.   The fountain solution concentrated composition for lithographic printing plates according to claim 1 or 2, comprising 10% by mass or more and less than 35% by mass of propylene glycol mono n-butyl ether or 10% by mass or more and less than 35% by mass of propylene glycol monomethyl ether.   The fountain solution concentrated composition for lithographic printing plates according to any one of claims 1 to 3, comprising 0.05 to 1.0 mol / liter of at least one selected from organic acids, inorganic acids and salts thereof. .   The lithographic printing according to any one of claims 1 to 4, comprising 0.05 to 3.0% by mass of at least one selected from a bromonitroalcohol-based compound and a 1,2-benzisothiazolin-3-one compound. A fountain solution concentrate for printing plates.