JPH08132753A - Damping water composition for planographic printing - Google Patents

Abstract

PURPOSE: To prepare a damping water compsn. capable of being highly conc. and having no problem from an aspect of safety and sanitation by adding a compd. obtained by adding ethylene oxide and propylene oxide to trihydric or more polyhydric alcohol. CONSTITUTION: A damping water compsn. for planographic printing containing a compd. obtained by the co-addition condensation of ethylene oxide/propylene oxide to trihydric or more polyhydric alcohol is prepared. As a concrete example of trihydric alcohol, there are glycerine, diglycerine, triglycerine and the like and, as a concrete example of tetrahydric alcohol, there is pentaerithritol and, as a concrete example of hexahydric alcohol, there is sorbitol. The wt. ratio of ethylene oxide and propylene oxide added to those alcohols is pref. 10:90-75:25. The damping water compsn. can be suitably adapted to a planographic printing plate obtained by the imagewise exposure and development of a photosensitive planographic printing plate wherein a photosensitive layer is provided on an aluminum plate being a support.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a fountain solution composition for lithographic printing.

[0002]

2. Description of the Related Art Lithographic printing is a printing method that skillfully utilizes the property that water and oil are essentially immiscible. The printing plate surface has a region that receives water and repels oil-based ink, and a water-repellent oil-based ink. , The former is a non-image area and the latter is an image area. Then, at the time of printing, by dampening the non-image area with a fountain solution containing a desensitizing agent, the surface chemical difference between the image area and the non-image area is enlarged, and ink repulsion and image It increases the ink receptivity of the area.

As such a desensitizing agent which has been generally known from the past, as an alkali metal salt or ammonium salt of dichromic acid, phosphoric acid or a salt thereof, for example, an ammonium salt, gum arabic, carboxymethyl cellulose (CMC). There is an aqueous solution to which a colloidal substance such as is added. However, these fountain solutions have the drawback that they are difficult to evenly wet the non-image areas of the plate, so that the prints sometimes become soiled and considerable skill is required to adjust the fountain solution supply.

In order to improve this drawback, a Dahlgren system using an aqueous solution containing about 20 to 25% of isopropyl alcohol as dampening water has been proposed and is widely used. According to this method, wetting of the non-image area is improved,
A small amount of dampening water is required, the supply balance between the printing ink and water can be easily adjusted, the amount of dampening water emulsified in the printing ink is reduced, and the transferability of the printing ink to the blanket is further reduced. There are various advantages in terms of workability and accuracy of the obtained printed matter such as improvement in quality.

However, since isopropyl alcohol is different from water in ease of evaporation, a special expensive device for keeping the isopropyl alcohol concentration of the dampening water constant is required. In addition, isopropyl alcohol has a peculiar unpleasant odor and also has a problem in toxicity, and is regulated by the Organic Law of the Labor Safety Law . Furthermore, since it is a compound that easily ignites, it falls under the Hazardous Substances of the Fire Service Law, and it requires careful handling and storage management, which is not preferable in the work environment. Also,
Even when the dampening water added with this isopropyl alcohol is applied to offset printing using a normal water stick, isopropyl alcohol evaporates on the roller and the plate surface, so that there is a problem that the effect cannot be exhibited. there were.

Therefore, a fountain solution containing no isopropyl alcohol has been desired. In order to achieve these objects, for example, JP-B-55-25075, JP-B-55-19757, and JP-B-58-5797 describe compositions containing various surfactants. However, when these are used as dampening water, the ink / water is violently moving under the high-speed rotating ink roller, printing plate, and dampening water supply roll, so that water may adhere to the ink film. However, it was not sufficient to completely eliminate the problem of ink spreading on the surface of water. Further, there is a drawback that the fountain solution containing these surfactants easily foams during pumping or stirring.

US Pat. No. 3,877,372 also describes a fountain solution containing a mixture of ethylene glycol monobutyl ether and at least one of hexylene glycol and ethylene glycol. US Patent No.
No. 4,278,465 includes n-hexoxydiethylene glycol, n-hexoxyethylene glycol, 2-ethyl-
A fountain solution containing at least one of 1,3-hexanediol, n-butoxyethylene glycol acetate, n-butoxydiethylene glycol acetate and 3-butoxy-2-propanol is described. JP-A-5
No. 7-199693, 2-ethyl-1,3-hexanediol and completely water-soluble propylene glycol, ethylene glycol, dipropylene glycol, diethylene glycol, hexylene glycol, triethylene glycol, tetraethylene glycol, tripropane. A fountain solution containing at least one of glycol and 1,5-pentanediol is described. Since these fountain solution compositions do not contain isopropyl alcohol, they are advantageous in terms of safety and hygiene, but in a lithographic printing plate using an anodized aluminum plate as a support, the non-image area during printing is not sufficiently wet, There is a problem in that the non-image area becomes dirty at the time of high-speed printing, the shape of the halftone dot image area becomes large, or unevenness occurs, that is, so-called entanglement of the halftone dot image area occurs. Further, 2-ethyl-1,3-hexanediol has a problem that it has insufficient solubility in water and is disadvantageous in obtaining a concentrated concentrated fountain solution composition.

Further, JP-A-5-221179 discloses that glycerin, sorbitol, 3 methylpentane-
A fountain solution containing a propylene oxide adduct of a polyhydric alcohol such as a propylene oxide adduct of 1,3,5-triol is described. These dampening solutions are not suitable for long-run printing that prints 10,000 sheets or more by themselves, so tetrapropylene glycol monomethyl ether,
Since it is necessary to use a volatile organic solvent such as 3-methyl-2-methoxybutanol or methyl carbitol in combination, it cannot be said to be perfect in terms of safety and hygiene. Further, these isopropyl alcohol substitute compounds are generally high boiling point solvents, and when the water evaporates, the high boiling point organic solvent remains, which has a defect that the image area of the lithographic printing plate is damaged. found.

[0009]

SUMMARY OF THE INVENTION Accordingly, the object of the present invention is to provide a printing machine of any mechanism without the toxicity and drawbacks of the above-mentioned conventional dampening solution, without requiring specialized skill in printing work. , Isopropyl alcohol completely replaced, and printing plate, especially aluminum plate with electrochemically roughened and anodized support, causes printing problems such as stain, blinding and water loss. In addition to suppressing the above, it does not impair the image area of the printing plate, has good compatibility with other fountain solution composition components, enables high concentration, and poses safety and health and fire safety problems. It is another object of the present invention to provide a fountain solution composition for lithographic printing, which can easily obtain a high-quality printed matter.

[0010]

Means for Solving the Problems As a result of intensive studies to achieve the above object, the present inventor has found that the above object can be solved by developing the following fountain solution composition for lithographic printing. The heading has arrived at the present invention. That is, the present invention is a fountain solution composition for lithographic printing containing a compound obtained by copolymerizing ethylene oxide / propylene oxide with a polyhydric alcohol having a valence of 3 or more. In the present specification, the concentrated product is referred to as a fountain solution composition.

The present invention will be described in detail below. The above-mentioned compound used in the present invention is synthesized by subjecting alcohols to an addition reaction of ethylene oxide and propylene oxide. Examples of alcohols include triglyceride such as glycerin, diglycerin, and triglycerin such as polyglycerin, trimethylolmethane, trimethylolethane, trimethylolpropane, hexanetriol, and other triols, tetravalent alcohol such as pentaerythritol, Examples of the hexahydric alcohol include sorbitol and the like. Further, polyhydric alcohols include disaccharides such as sucrose, low molecular weight polyvinyl alcohol, dextrin and the like.

The weight ratio of ethylene oxide and propylene oxide added to these alcohols is 1
0:90 to 75:25 is desirable, especially 10:90
˜50: 50 is more desirable. If the ratio of ethylene oxide is less than 10%, the water solubility decreases, and the compatibility with other components of the fountain solution composition, water-soluble polymer, organic and inorganic acid salts, and water decreases, resulting in a degree of concentration. A fountain solution composition having a high viscosity cannot be obtained. Further, when the ratio of ethylene oxide is more than 75%, the effect of lowering the surface tension cannot be obtained. Compounds obtained by adding a specific ratio of ethylene oxide and propylene oxide to these alcohols can replace isopropyl alcohol without being used in combination with a volatile organic solvent.

As the bond structure of ethylene oxide and propylene oxide, a block structure in which ethylene oxide is first added and then propylene oxide is added, a block structure in which propylene oxide is first added and then ethylene oxide is added, and at the same time ethylene Although there is a random structure in which oxide and propylene oxide are added, almost the same effect can be obtained with any structure. When the number of additions of ethylene oxide and propylene oxide is expressed as the molecular weight of the whole compound, the preferable molecular weight of the compound is 500 to 10,000, and particularly preferably the molecular weight is 1,000 to 5,000. Molecular weight is 50
If it is less than 0, the effect of lowering the surface tension is greatly reduced,
Print performance is impaired. On the other hand, if it is more than 10000, it takes a long time to respond to the surface tension on a printing machine rotating at a high speed, so that the effect is not obtained and the printing performance is impaired. Furthermore, among compounds obtained by adding a specific ratio of ethylene oxide and propylene oxide to these alcohols, a compound having three or more copolymer chains of ethylene oxide and propylene oxide is always a problem with a conventional isopropyl alcohol substitute. It was also discovered that it did not invade the image area of the printing plate at all.

The above compound used in the present invention is 0.01 to
By using a fountain solution containing 5% by weight, more preferably 0.02 to 2% by weight, even if isopropyl alcohol is replaced, stains on non-image areas and halftone image areas when printing on a PS plate The stain is gone. Moreover, unlike the conventional isopropyl alcohol substitute, it does not attack the image area of the printing plate at all. 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 (for example, dextrin, enzyme-degraded dextrin, hydroxypropylated enzyme-degraded dextrin,
Carboxymethyl starch, starch phosphate, octenyl succinate starch), alginates, fibrin derivatives (eg carboxymethyl cellulose, carboxyethyl cellulose,
Natural products such as hydroxyethylcellulose, methylcellulose, hydroxypropylmethylcellulose, their glyoxal modified products and the like) and their modified products, polyvinyl alcohol and its derivatives, polyvinylpyrrolidone, polyacrylamide and its copolymers, polyacrylic acid and its copolymers , Vinyl methyl ether / maleic anhydride copolymer, vinyl acetate / maleic anhydride copolymer, and the like. These polymer compounds can be used alone or as a mixture, and the concentration range thereof is 0.0001 to 5% by weight, more preferably 0.003 to 5% by weight in the following "fountain solution". -1% by weight is suitable.

The fountain solution is generally in the acidic region, that is, p
It is desirable to use in the range of H3 to 6 or so. pH 3
If it is less than the above range, the etching effect on the support becomes strong and the printing durability is deteriorated. In order to adjust the pH value to 3 to 6, it is generally sufficient to add a mineral acid, an organic acid or an inorganic acid salt. The appropriate amount of addition is 0.001 to 5% by weight in dampening water. The mineral acids include nitric acid, sulfuric acid, phosphoric acid and the like, and the organic acids include citric acid, acetic acid, glycolic acid, gluconic acid, oxalic acid, malonic acid, p-toluenesulfonic acid,
Examples thereof include tartaric acid, malic acid, lactic acid, levulinic acid and organic phosphonic acid. These mineral acids, organic acids or inorganic salts may be used alone or in combination of two or more. Furthermore, the fountain solution composition of the present invention can contain an alkali metal hydroxide, an alkali metal phosphate, an alkali metal carbonate, a silicate, etc., and can be used in an alkaline region at a pH of about 7 to 11.

In addition to the above components, a chelating compound may be added to the fountain solution composition of the present invention. Usually, the fountain solution composition is used by diluting a concentrated composition with tap water, well water or the like. At this time, calcium ions or the like contained in the tap water or well water diluted may affect printing, and may cause stains on the printed matter. In such a case, the above-mentioned drawbacks can be eliminated by adding a chelate compound. Preferred chelate compounds include, for example, ethylenediaminetetraacetic acid, its potassium salt, its sodium salt; diethylenetriaminepentaacetic acid, its potassium salt, its sodium salt; triethylenetetraminehexaacetic acid, its potassium salt, its sodium salt; hydroxyethylethylenediaminetriacetic acid. , Its potassium salt, its sodium salt; nitrilotriacetic acid, its potassium salt, its sodium salt; 1,2-
Diaminocyclohexanetetraacetic acid, its potassium salt,
Its sodium salt; aminopolycarboxylic acids such as 1,3-diamino-2-propanoltetraacetic acid, its potassium salt, its sodium salt and the like, 2-phosphonobutanetricarboxylic acid-1,2,4, its potassium salt, Its sodium salt; 2-phosphonobutane tricarboxylic acid-2,
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, its sodium salt;
Aminotri (methylenephosphonic acid), its potassium salt,
Examples thereof include organic phosphonic acids such as sodium salts thereof and phosphonoalkane tricarboxylic acids.

Instead of the sodium salt or potassium salt of the chelating agent, salts of organic amines are also effective. These chelating agents are selected so that they are stable in the fountain solution and do not impair the printability. The amount to be added is 0.001 to 3% by weight, preferably 0.01 to 1% by weight, in dampening water. Furthermore, a coloring agent, a preservative and the like can be added to the fountain solution composition of the present invention. For example, benzoic acid and its derivative, phenol, formalin, sodium dehydroacetate, 4-isothiazolin-3-one compound, benzisothiazoline compound, halogenonitropropane compound, etc. are added in the range of 0.0001 to 1% by weight in moistened water. Is also good.

The fountain solution composition of the present invention further comprises corrosion inhibitors such as magnesium nitrate, zinc nitrate, calcium nitrate, sodium nitrate, potassium nitrate, lithium nitrate and ammonium nitrate, and hardeners such as chromium compounds and aluminum compounds. , Cyclic ethers: organic solvents such as 4-butyrolactone, benzyl alcohol, ethylene glycol monophenyl ether, ethyl alcohol, n-propyl alcohol, water-soluble surface-active organometallic compounds and silicone-based compounds described in JP-A-61-193893. An antifoaming agent can be added in the range of 0.0001 to 1% by weight of the fountain solution used.

The fountain solution composition of the present invention may further contain a small amount of a surfactant. For example, as the anionic surfactant, fatty acid salts, abietic acid salts, hydroxyalkanesulfonic acid salts, alkanesulfonic acid salts,
Dialkylsulfosuccinates, linear alkylbenzenesulfonates, branched alkylbenzenesulfonates, alkylnaphthalenesulfonates, alkylphenoxypolyoxyethylenepropylsulfonates, polyoxyethylenealkylsulfophenyl ether salts, N-methyl-N -Oleyl taurine sodiums,
N-alkylsulfosuccinic acid monoamide disodium salt, petroleum sulfonate, hydrogenated castor oil, sulfated beef tallow oil, sulfate ester salt of fatty acid alkyl ester, alkyl sulfate ester salt, polyoxyethylene alkyl ether sulfate ester salt, fatty acid monoglyceride sulfate ester Salts, polyoxyethylene alkylphenyl ether sulfuric acid ester salts, polyoxyethylene styryl phenyl ether sulfuric acid ester salts, alkyl phosphoric acid ester salts, polyoxyethylene alkyl ether phosphoric acid ester salts, polyoxyethylene alkylphenyl ether phosphoric acid ester salts, styrene-maleic anhydride Examples include partially saponified products of acid copolymers, partially saponified products of olefin-maleic anhydride copolymers, and naphthalenesulfonate formalin condensates. It is. Among these, dialkyl sulfosuccinates, alkyl sulfates and alkyl naphthalene sulfonates are particularly preferably used.

As the nonionic surfactant, polyoxyalkyl ethers, polyoxyethylene alkylphenyl ethers, polyoxyethylene polystyrylphenyl ethers, polyoxyethylene polyoxypropylene alkyl ethers, glycerin fatty acid partial esters, Sorbitan fatty acid partial ester, pentaerythritol fatty acid partial ester, propylene glycol monofatty acid partial ester, sucrose fatty acid partial ester, polyoxyethylene sorbitan fatty acid partial ester, polyoxyethylene sorbitol fatty acid partial ester, polyglycerin fatty acid partial ester , Polyoxyethylenated castor oils, polyoxyethylene glycerin fatty acid partial esters, fatty acid diethanolamides, N, N-bis- - hydroxyalkylamines,
Examples thereof include polyoxyethylene alkylamine, triethanolamine fatty acid ester, trialkylamine oxide and the like. Among them, 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. Further, a fluorine-based surfactant can be mentioned. For example, as the fluorine-based anionic surfactant, as a perfluoroalkyl sulfonate, a perfluoroalkyl carboxylate, a perfluoroalkyl phosphate, and a fluorine-based nonionic surfactant. Examples include perfluoroalkyl ethylene oxide adducts, perfluoroalkyl propylene oxide adducts, and fluorine-based cationic surfactants such as perfluoroalkyl trimethyl ammonium salts.
Considering the foaming point, the content of these surfactants is
Appropriately 10% by weight or less, preferably 0.01 to 3.0% by weight, in the fountain solution.

Further, in the fountain solution composition of the present invention, alcohols and / or glycols such as, for example, moisturizing agents
n-propyl alcohol, ethylene glycol, propylene glycol, triethylene glycol, butylene glycol, hexylene glycol, tetraethylene glycol, diethylene glycol, dipropylene glycol, polyethylene glycol, polypropylene glycol, glycerin, diglycerin, polyglycerin, sorbitol, pentaerythritol , Trimethylolpropane, methoxyethanol, ethoxyethanol, butoxyethanol, 3-methoxybutanol, 3-methyl-3-methoxybutanol, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, diethylene glycol monopropyl ether, triethylene glycol monoethyl ether. Me Ether, triethylene glycol monoethyl ether, triethylene glycol monobutyl ether, triethylene glycol monopropyl ether, tetraethylene glycol monomethyl ether, tetraethylene glycol monoethyl ether, tetraethylene glycol monobutyl ether, tetraethylene glycol monopropyl ether, propylene glycol Methyl ether, propylene glycol ethyl ether, propylene glycol propyl ether, propylene glycol isopropyl ether, propylene glycol butyl ether, propylene glycol t-
Butyl ether and the like can also be used. These wetting agents may be used alone or in combination of two or more. Generally, it is desirable to use the wetting agent in an amount of 0.1 to 25% by weight in the fountain solution composition.

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 It is a printing plate provided with photosensitivity and can be suitably used for a lithographic printing plate obtained by imagewise exposing and developing a PS plate). A preferred PS plate is a photosensitive layer comprising a mixture of a diazo resin (a salt of a condensate of p-diazodiphenylamine and paraformaldehyde) as described in British Patent 1,350,521 and a shellac. On an aluminum plate, a polymer having a diazo resin as described in British Patent Nos. 1,460,978 and 1,505,739 and a hydroxyethyl methacrylate unit or a hydroxyethyl acrylate unit as a main repeating unit. And a photosensitive layer comprising a mixture thereof with an aluminum plate, and JP-A-2-236552 and JP-A-4-27.
Negative-type PS plates such as those having a photosensitive polymer system containing a dimethylmaleimide group described in JP-A-4429 on an aluminum plate, and O-quinone diad sensitization as described in JP-A No. 50-125806. A positive PS plate in which a photosensitive layer made of a mixture of a resin and a novolac type phenol resin is provided on an aluminum plate is included. It can also be used for a positive PS plate that has been subjected to a burning treatment.

If desired, an alkali-soluble resin other than the above-mentioned alkali-soluble novolac resin can be added to the composition forming the photosensitive layer. Examples thereof include styrene-acrylic acid copolymer, methylmethacrylate-methacrylic acid copolymer, alkali-soluble polyurethane resin, alkali-soluble vinyl resin and alkali-soluble polybutyral resin described in JP-B-52-28401. it can. Further, a PS plate having a photosensitive layer of a photopolymerizable photopolymer composition as described in U.S. Pat.
A PS plate having a photosensitive layer made of a mixture of azide and a water-soluble polymer as described in each specification of 1,495,861 provided on an aluminum plate is also preferable. When the dampening water composition of the present invention is used, it is used in tap water, well water, etc. 30 to 5 times.
Generally diluted to 00 times, there is no background stains and oxidation stains, printing is possible with a small amount of use, good printed matter is obtained, printing efficiency is improved, and productivity is improved. You can In particular, when used in a continuous water supply type printing machine represented by the Dahlgren method, a good printed matter can be obtained without using isopropyl alcohol. Further, even if 1 to 15% by weight of isopropyl alcohol is used together in the fountain solution, there is no problem in print quality.

[0025]

INDUSTRIAL APPLICABILITY The fountain solution composition of the present invention substitutes isopropyl alcohol in fountain solution in all continuous water supply type printing machines and has good printability. Further, it is possible to highly concentrate, and it is possible to obtain a stable and excellent printed matter without problems in terms of labor safety and fire safety.

[0026]

EXAMPLES Next, the present invention will be described more specifically by way of examples. Unless otherwise specified,% means% by weight. A concentrated fountain solution composition having the following composition was prepared. Isopropyl alcohol substitute shown in Table 1 40 parts by weight Water-soluble polymer (carboxymethyl cellulose) 3 parts by weight (Serogen, Daiichi Pharmaceutical Co., Ltd.) pH buffer: phosphoric acid 85% 1 part by weight Phosphoric acid second Ammonium 1 part by weight Citric acid 2 parts by weight Nitrate: Magnesium nitrate 2 parts by weight Calcium nitrate 1 part by weight Pure water added 100 parts by weight

[0027]

[Table 1] Table 1 Isopropyl alcohol substitute Polyhydric alcohol EO / PO ratio ^* Molecular weight Example 1 Sorbitol 25/75 1000 2 Sorbitol 15/85 3000 3 Sorbitol 25/75 3000 4 Sorbitol 40/60 3000 5 Sorbitol 25/75 5000 6 Glycerin 25/75 3000 Comparative Example 1 Sorbitol 25/75 400 2 Sorbitol 0/100 3000 3 Sorbitol 80/20 3000 4 Sorbitol 100/0 3000 5 Sorbitol 25/75 15000 6 Butanol 25/75 3000 7 Octanediol 25 / 75 3000 8 Ethylene glycol monobutyl ether 9 Hexylene glycol 10 Isopropyl alcohol * EO / PO ratio: weight ratio of ethylene oxide / propylene oxide

Test method FPS (Positive type PS plate manufactured by Fuji Photo Film Co., Ltd.) as a printing plate was exposed using a film of solid part and 30% halftone dot part, PS automatic developing machine 800EII, positive developer DP
-4 (8 times diluted with water), Positive finisher FP
(Double diluted with water) (Fuji Photo Film Co., Ltd.)
Manufactured by Mitsubishi Heavy Industries Co., Ltd. and attached to a printing machine manufactured by Mitsubishi Heavy Industries (continuous water supply device, equipped with a diamond type), and sheet-fed process ink: Hiplus Indigo (manufactured by Toyo Ink) and Example 1 in Table 1. .About.6 and the concentrated liquids of Comparative Examples 1 to 10 were printed using dampening water diluted 100 times with tap water. In Comparative Example 10, 20% of isopropyl alcohol was further added.

A. Stability of concentrated dampening water solution: Example 1 in Table 1
~ 6 and the concentrated solutions of Comparative Examples 1 to 10 are formulated, and the stability of the solutions is visually evaluated after standing for 1 week. No problem A Separation, turbidity B Separation C b. Continuous printing stability: The amount of dampening water that does not cause stains or water loss (minimum amount of water rise) is calculated, and the number of prints until a good print cannot be obtained due to stains on the print or water loss. Determined by 10000 sheets or more A 10000 to 3000 sheets or more B 2999 to 1 sheet C None D

C. Emulsification property: The emulsification state of the ink on the ink kneading roller when printing 10,000 sheets is examined. Good A bad B bad C d. Image area deterioration: The printing machine is stopped, and the solid area of the PS plate becomes 3
5 μl, 10 μl, 20 μl and 50 μl of the respective dampening water were added dropwise to the image portion of the 0% halftone dot portion using a syringe, and the mixture was left for 60 minutes. After that, printing is restarted and deterioration of the image area is evaluated. No problem A Some deterioration (with ring mark) B deterioration C The test results are shown in Tables 2 and 3.

As a result of testing the fountain solution of the example,
(A) Concentrated dampening water solution stability, (b) Continuous printing stability,
Both of (c) emulsifying property and (d) deterioration of image area were excellent, and a good printed matter similar to the fountain solution using the isopropyl alcohol of Comparative Example 10 was obtained. Further, this dampening water, unlike isopropyl alcohol, has no problems in terms of occupational safety and fire safety.

[0032]

[Table 2] Table 2 ─────────────────────────────────── Example ratio Comparative example 1 2 3 4 5 6 1 2 3 4 5 6 7 8 9 10 Concentrated fountain solution stability AAAAAAACAABBCBCA Continuous printing stability BAAAAADBBDCCCDDA Emulsification AAAAAACBCCBBBCCA

[0033]

[Table 3] Table 3 ──────────────────────────────── Dropping amount Example ratio Comparison example 1 2 3 4 5 6 1 2 3 4 5 6 7 8 9 10 5 μl AAAAAAABAACCCBCA 10 μl AAAAAAABAACCCBCA 20 μl AAAABAABAACCCCCA 50 μl AAAABBACAACCCCCA

Claims (1)

[Claims] 1. A fountain solution composition for lithographic printing containing a compound obtained by adding ethylene oxide and propylene oxide to a polyhydric alcohol having a valence of 3 or more.