JPH1178281A - Dampening water composition for lithographic printing plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To lower dynamic surface tension with relatively small amount by safety in a working environment by incorporating at least one type of compound represented by a formula (I) or (II) and compound reprsented by a formula (III). SOLUTION: The dampening water composition for a lithographic printing plate comprises at least one type of compound represented by a formula (I) or (II) and compound represented by a formula (III). In the formula (I), R<1> is hydrogen atom or 1-8C alkyl, R<2> is hydrogen atom or methyl group, m is integer of 1 to 4, R<3> is hydrogen atom or 1-12C alkyl, n, o and p are each integer of 1 to 40, and R<4> is 2-12C alkyl. As an embodiment of the compound represented by the formula (I), ethyleneglycolmonomethylether or the like is preferable. As an embodiment of the compound represented by the formula (II), compound containing about 40% or less of ethylene oxide in total molecules and molecular weight of polypropylene oxide of about 2500 or less is suitably used. As an embodiment of the compound represented by the formula (III), ethylpyrrolidone or the like is used.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a fountain solution composition useful for offset printing of a lithographic printing plate.

[0002]

2. Description of the Related Art Lithographic printing is a printing method that skillfully utilizes the property that water and oil are not essentially mixed. 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. The desensitizing agent enlarges the surface chemical difference between the image area and the non-image area by wetting the non-image area with a fountain solution containing the same, thereby increasing the ink repellency of the non-image area and the image area. It has the effect of increasing ink receptivity. As the fountain solution generally conventionally known, alkali metal salts or ammonium salts of dichromic acid, phosphoric acid or a salt thereof, for example, ammonium salt,
Gum arabic, carboxymethyl cellulose (CMC)
There is an aqueous solution to which a colloidal substance such as is added. However, the fountain solution containing only these compounds has a disadvantage that it is difficult to uniformly wet the non-image area of the plate, so that the printed matter sometimes becomes dirty, and considerable skill is required to adjust the supply amount of the fountain solution. Required.

In order to remedy this drawback, a Dahlgren system using an aqueous solution containing about 20 to 25% of isopropyl alcohol as dampening water has been proposed. According to this method, the wetting of the non-image area is improved, the amount of the dampening solution is reduced, the balance between the supply amounts of the printing ink and water is easily adjusted, and the dampening solution in the printing ink is easily adjusted. There are many advantages in terms of workability and accuracy of the printed matter obtained, such as a reduction in the amount of emulsification of the ink and an improvement in the transferability of the printing ink to the blanket. However, since isopropyl alcohol is easy to evaporate, a special device for keeping the isopropyl alcohol concentration of the dampening solution constant is required, which is expensive in terms of price. Further, isopropyl alcohol has a peculiar unpleasant odor and also has a problem in toxicity, which is not preferable in a working environment. In addition, even if this dampening solution to which isopropyl alcohol is added is applied to offset printing using a normal water rod, the effect cannot be exerted because isopropyl alcohol evaporates on the roller and the plate surface, so that the effect cannot be exhibited. Had become.

[0004] Further, in recent years, public interest in industrial pollution has become extremely high, the regulation of chromium ion emission in wastewater has become strict, and the use of organic solvents such as isopropyl alcohol tends to be regulated in terms of safety and health. . For this reason, a fountain solution not containing these has been desired. In order to achieve these objects, for example, Japanese Patent Publication No. 55-2507
No. 5, JP-B-55-19775, JP-B-58
Japanese Patent No. 5797 describes compositions containing various surfactants, but when these are used as dampening solutions, the surfactant concentration must be considerably increased. In actual lithographic printing, the ink / water moves violently under an ink roll, a printing plate, and a dampening water supply roll rotating at a high speed. However, the combination of surfactants proposed above has not been sufficient to completely eliminate these problems. Further, there has been a drawback that the dampening solution containing these surfactants easily foams during pumping or stirring.

On the other hand, US Pat. No. 3,877,372 discloses ethylene glycol monobutyl ether and at least one of hexylene glycol and ethylene glycol.
Solutions containing mixtures with seeds are described. U.S. Pat. No. 4,278,467 includes n-hexoxydiethylene glycol, n-hexoxyethylene glycol,
A fountain solution containing at least one of 2-ethyl-1,3-hexanediol, n-butoxyethylene glycol acetate, n-butoxydiethylene glycol acetate, and 3-butoxy-2-propanol is described. JP-A-57-199693 discloses 2-ethyl-1,3-hexanediol and propylene glycol, ethylene glycol, dipropylene glycol, diethylene glycol, hexylene glycol, triethylene glycol and tetraethylene which are completely water-soluble. A fountain solution containing at least one of glycol, tripropane glycol and 1,5-pentanediol is described. Since these dampening solution compositions do not contain isopropyl alcohol, they are advantageous in terms of safety and hygiene. However, in the PS plate of an anodized aluminum substrate, it is hard to say that the non-image area is completely wet during printing, and particularly high speed. There has been a problem in that the non-image portion is stained during printing, and the shape of the halftone dot image portion is not normal, becomes large, and becomes uneven, that is, there is a problem that so-called tangling of the halftone dot image portion occurs. Furthermore, 2-ethyl-1,
3-Hexanediol has problems such as insufficient solubility in water, which is disadvantageous for obtaining a concentrated fountain solution composition and a fountain solution additive at a high concentration.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to provide a wet plate for a lithographic printing plate which can be replaced with an isopropyl alcohol-based material, which is safe in the working environment and can exert its effect sufficiently under the condition of a member rotating at a high speed. To provide a water composition.

[0007]

Means for Solving the Problems In order to achieve the above object, the present inventors have conducted research on components that are environmentally safe and can reduce the dynamic surface tension with a relatively small amount. The inventors have found that the above object can be easily solved by using the compound represented by the formula (III), and have reached the present invention. That is, the present invention provides a fountain solution for a lithographic printing plate comprising at least one compound represented by the following general formula (I) or (II) and a compound represented by the following general formula (III). A composition.

[0008]

Embedded image

Wherein R ¹ is a hydrogen atom or a carbon atom
And R ² represents a hydrogen atom or a methyl group; m represents an integer of 1 to 4; R ³ represents a hydrogen atom or an alkyl group having 1 to 12 carbon atoms; And p
Each represents an integer of 1 to 40, and R ⁴ has 2 carbon atoms.
And represents an alkyl group of -12. )

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The fountain solution composition of the present invention has a reduced dynamic surface tension due to a combination of the above components, and in particular, the wettability of a chromium roller and a rubber roller by a continuous water supply type fountain solution supply device. Since it is good, it can be supplied as a uniform water film to the non-image portion of the printing plate surface. Further, the foaming property, which is a problem in the surfactant system, is small, and the solvent odor becomes a refreshing odor as the environment of the printing room, thereby improving the working environment.

Specific examples of the compound represented by the general formula (III) used in the present invention include ethylpyrrolidone, butylpyrrolidone, pentapyrrolidone, hexapyrrolidone, octylpyrrolidone, laurylpyrrolidone and the like.
One or more of these compounds may be used. Among these compounds, those in which R ⁴ in the formula is an alkyl group having 6 or more carbon atoms are preferably used. The content of the compound represented by the general formula (III) is 0.05 to 3.0% by weight, preferably 0.1 to 1.0% by weight based on the total weight of the fountain solution composition.
% By weight.

Specific examples of the compound represented by the general formula (I) used in the present invention include ethylene glycol monomethyl ether, diethylene glycol monomethyl ether, triethylene glycol monomethyl ether, polyethylene glycol monomethyl ether, ethylene glycol monoethyl ether, and diethylene glycol. Monoethyl ether, triethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monobutyl ether, triethylene glycol monobutyl 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 monotertiary butyl ether, diethylene glycol monotertiary butyl ether, triethylene glycol monotertiary butyl ether, ethylene glycol monohexyl ether, diethylene glycol monohexyl ether, triethylene glycol monohexyl ether , Ethylene glycol monophenyl ether, diethylene glycol monophenyl ether, triethylene glycol monophenyl ether, propylene glycol, dipropylene glycol, tripropylene glycol, tetrapropylene glycol, propylene glycol monomethyl ether, dipropylene glycol monomethyl ether ,

[0013] Tripropylene 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 Propylene glycol monopropyl ether, propylene glycol monoisopropyl 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 Ether, dipropylene glycol monoisobutyl ether, tripropylene glycol monoisobutyl ether, propylene glycol mono t-butyl ether, dipropylene glycol mono t-butyl ether, tripropylene glycol mono t-butyl ether and the like. Of these compounds, ethylene glycol monobutyl ether, ethylene glycol monotertiary butyl ether, propylene glycol monopropyl ether, propylene glycol monobutyl ether and the like are preferably used.

As a specific example of the compound represented by the general formula (II), those in which the percentage of ethylene oxide in the total molecule is 40% or less and the molecular weight of polypropylene oxide is 2500 or less are preferably used. Among these compounds, compounds having a dynamic surface tension of 55 dynes / cm or less in a 0.2% aqueous solution are more preferably used. The fountain solution composition of the present invention has the above general formula (I) or (I)
At least one compound of the formula (I), the content of these compounds being 0.0
5 to 5% by weight is suitable, preferably 0.1 to 3% by weight
It is. If the amount is less than 0.05% by weight, the wettability of the fountain solution composition is poor, and if it exceeds 5% by weight, a roller strip or the like is likely to be caused.

In the present invention, in addition to the above-mentioned compounds, the following compounds may be optionally added to adjust the dynamic surface tension, solubilize the ink, or keep the mixing ratio (emulsification ratio) of the printing ink within an appropriate range. Can be added. Molecular weight 200-1
000 polypropylene glycol and their compounds monomethyl ether, monoethyl ether, monopropyl ether, and isopropyl ether, monobutyl ether, 2-ethyl-1,3-hexanediol,
-Ethylene oxide and / or propylene oxide adduct of ethyl-1,3-hexanediol, ethylene and / or propylene oxide adduct of acetylene alcohol or acetylene glycol, propylene oxide adduct of trimethylolpropane, and propylene oxide addition of glycerin Stuff,
Propylene oxide adduct of sorbitol, 3-methyl-3
-Methoxybutanol, methoxybutanol, tetrahydrofurfuryl alcohol and the like.

Among these compounds, 2-ethylhexanediol and acetylene glycol ethylene oxide adduct are particularly effective as compounds effective as a dynamic surface tension aid. As the solubilizer, ethylene glycol mono-tert-butyl ether, 3-methyl-3-methoxybutanol, 3-methoxybutanol, tetrahydrofurfuryl alcohol and the like are preferably used. As the ink emulsification control agent, ethylene oxide adduct of 2-ethyl-1,3-hexanediol, ethylene oxide adduct of trimethylolpropane, and the like can be suitably used. These compounds may be used alone or in combination of two or more kinds. The range which can be suitably used is 0.01 to 7% by weight, more preferably 0.05 to 5% by weight.

As the pH buffer used in the fountain solution composition of the present invention, a water-soluble organic acid and / or inorganic acid or a salt thereof can be used. It is effective for buffering, moderate etching of the lithographic printing plate support or anticorrosion. Preferred organic acids include, for example, citric acid, ascorbic acid, malic acid, tartaric acid, lactic acid, acetic acid, gluconic acid, acetic acid, hydroxyacetic acid,
Examples include oxalic acid, malonic acid, levulinic acid, sulfanilic acid, p-toluenesulfonic acid, phytic acid, and organic phosphonic acid. As the inorganic acid, for example, phosphoric acid, nitric acid, sulfuric acid,
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 may be used alone. Or a mixture of two or more.

The addition amount of these pH buffers to the fountain solution composition of the present invention is preferably in the range of 0.001 to 0.3% by weight, and the pH value of the fountain solution composition is in the range of 3 to 7. Although it is preferable to use in an acidic region, it can also be used in an alkaline region having a pH of 7 to 11 containing an alkali metal hydroxide, phosphoric acid, an alkali metal salt, an alkali metal carbonate, or a silicate.

The fountain solution composition of the present invention further comprises (a) a water-soluble polymer compound, (b) a surfactant, (c) a chelate compound, (d) a preservative, (e) a rust inhibitor, (F) a coloring agent,
Components such as (g) fragrance and (h) defoamer can be added as needed. Examples of the (a) water-soluble polymer compound which can be used in the present invention include gum arabic and starch derivatives (eg, dextrin, enzymatically decomposed dextrin, hydroxypropylated enzymatically decomposed dextrin, carboxymethylated starch, phosphate starch, octenylsuccinated starch) ,
Natural products such as alginate, cellulose derivatives (eg, carboxymethylcellulose, carboxyethylcellulose, methylcellulose) and their modified products, polyethylene glycol and its copolymer, polyvinyl alcohol and its derivative, polyvinylpyrrolidone, polyacrylamide and its copolymer , Polyacrylic acid and its copolymer, vinyl methyl ether / maleic anhydride copolymer,
Examples include a vinyl acetate / maleic anhydride copolymer, polystyrene sulfonic acid, and a synthesized product of the copolymer. The content of the water-soluble polymer is 0.000 with respect to the fountain solution composition.
1-0.1% by weight is suitable, more preferably 0.1% by weight.
0005-0.05% by weight.

The surfactant (b) which can be used in the present invention may be added as a solubilizing auxiliary wetting aid. For example, anionic surfactants include fatty acid salts, abietic acid salts, hydroxyalkanesulfonates, alkanesulfonates, dialkylsulfosuccinates, straight-chain alkylbenzenesulfonates, branched-chain alkylbenzenesulfonates, alkylnaphthalenes Sulfonates, alkylphenoxypolyoxyethylenepropyl sulfonates, polyoxyethylene alkylsulfenyl ether salts, N-methyl-N-oleyltaurine sodium salts, N-alkylsulfosuccinic acid monoamide disodium salts, petroleum sulfonates, Sulfated castor oil, sulfated tallow oil, sulfates of fatty acid alkyl esters, alkyl sulfates, polyoxyethylene alkyl ether sulfates, fatty acid monoglyceride sulfate Ester salts, polyoxyethylene alkyl phenyl ether sulfates, polyoxyethylene styryl phenyl ether sulfates, alkyl phosphates, polyoxyethylene alkyl ether phosphates, polyoxyethylene alkyl phenyl ether phosphates, styrene-anhydride Partially saponified products of a maleic acid copolymer, partially saponified products of an olefin-maleic anhydride copolymer, and formalin condensates of naphthalenesulfonic acid salt are exemplified. Of these, dialkyl sulfosuccinates, alkyl sulfates and alkyl naphthalene sulfonates are particularly preferably used.

Examples of the nonionic surfactant include polyoxyethylene alkyl ethers, polyoxyethylene alkyl phenyl ethers, polyoxyethylene polystyryl phenyl ethers, polyoxyethylene polyoxypropylene alkyl ethers, and glycerin fatty acid partial esters. , Sorbitan fatty acid partial esters, pentaerythritol fatty acid partial esters, propylene glycol monofatty acid esters, sucrose fatty acid partial esters, polyoxyethylene sorbitan fatty acid partial esters, polyoxyethylene sorbitol fatty acid partial esters, polyethylene glycol fatty acid esters Kind,
Polyglycerin fatty acid partial esters, polyoxyethylenated castor oils, polyoxyethylene glycerin fatty acid partial esters, fatty acid diethanolamides, N,
Examples include N-bis-2-hydroxyalkylamines, polyoxyethylene alkylamines, triethanolamine fatty acid esters, and trialkylamine oxides. In addition, a fluorine-based surfactant and a silicon-based surfactant can also be used. Among them, polyoxyethylene alkyl phenyl ethers, polyoxyethylene-polyoxypropylene block polymers and the like are preferably used. Further, a surfactant such as a silicon derivative or a fluorine derivative may also be used. In consideration of foaming, the content of these surfactants is 1.0% by weight or less,
Preferably 0.001 to 0.5% by weight is appropriate. Also, two or more kinds can be used in combination.

In the present invention, (c) a chelate compound may be added. Usually, the concentrated dampening solution composition is diluted with tap water, well water and the like before use. At this time, calcium ions and the like contained in the diluted tap water or well water may adversely affect the printing and cause the printed matter to be easily stained. In such a case, the above disadvantage can be solved by adding a chelate compound. Preferred chelating 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; Acetic acid, its potassium salt, its sodium salt; nitrilotriacetic acid, its sodium salt; 1-hydroxyethane-
Organic phosphonic acids or phosphonoalkanetricarboxylic acids such as 1,1-diphosphonic acid, its potassium salt, its sodium salt; aminotri (methylenephosphonic acid), its potassium salt, its sodium salt and the like can be mentioned. Organic amine salts are also effective in place of the sodium or potassium salts of the above chelating agents. These chelating agents are selected from those which are stably present in the fountain solution composition and do not inhibit printability. The amount added to the fountain solution composition is 0.0001 to 1.0% by weight, preferably 0.1% by weight.
0005-0.1% by weight is suitable.

(D) Preservatives which can be used in the present invention include phenol or its derivatives, formalin, imidazole derivatives, sodium dehydroacetate, 4-isothiazolin-3-one derivatives, benztriazole derivatives, amidine or guanidine derivatives, quaternary Ammonium salts, pyridine, quinoline or guanidine derivatives, diazine or triazole derivatives, oxazole or oxazine derivatives, bromonitropropanol, 1,1-dibromo-1-nitro-2-ethanol, 3-bromo-3-
Examples thereof include nitropentane and 2,4-diol. The preferred amount of addition is an amount that exerts a stable effect on bacteria, molds, yeasts, etc., and varies depending on the type of bacteria, molds, and yeasts. .0
The range of weight% is preferable, and it is preferable to use two or more preservatives which are effective against various molds, bacteria and yeasts.

The rust preventive (e) which can be used in the present invention includes, for example, benzotriazole, 5-methylbenzotriazole, thiosalicylic acid, benzimidazole and derivatives thereof. As the coloring agent (f) that can be used in the present invention, food coloring agents and the like can be preferably used. For example, as a yellow pigment, CI No. 19140, 1598
5, red pigments are CI No. 16185, 4543
0, 16255, 45380, 45100, CI No. 42640 as a purple pigment, and CI No. 42 as a blue pigment.
42090, 73015, CI No. 4 as a green pigment
2095, and the like.

The fragrance (g) which can be used in the present invention can be suitably used for enhancing the printing environment by mixing a small amount of the fragrance. For example, a fountain odor, a lemon odor, a vanillin odor, and the like can be masked to provide a more convenient dampening solution. As the (h) antifoaming agent that can be used in the present invention, a silicone antifoaming agent is preferable, and among them, any of an emulsifying dispersion type and a solubilizing type can be used. The fountain solution composition of the present invention is generally concentrated and commercialized when it is used on a commercial basis. When using a concentrated liquid, it is more economical and preferable to use it after diluting it 30 to 500 times with tap water, well water, or the like.

[0026]

The fountain solution composition for a lithographic printing plate of the present invention comprises:
Even under the condition of a member that is environmentally safe, has a low dynamic surface tension, and exhibits high printability and stable stability over time even under conditions of a member that rotates at a high speed, it is possible to obtain a printed matter excellent in stability.

[0027]

Next, the present invention will be described more specifically with reference to examples. In addition,% indicates weight% unless otherwise specified.

Examples 1 to 3 and Comparative Examples 1 to 3 Various fountain solution compositions were prepared according to the compositions shown in Table 1. The unit is gram, and water was added to make up to 1000 ml.

[0028]

Table 1 Example Comparative Example Components 1 2 3 1 2 3 [Compound of the general formula (I)]-Ethylene glycol-300--380-monobutyl ether-Ethylene glycol 100-300--310 mono-t-butyl ether-Propylene glycol 150-----monobutyl ether [General formula (II Compound of the following formula (II) -a 10-20----Compound of the following (II) -b 20-30--30 [Compound of the general formula (III)]-Octylpyrrolidone-105- --Laurylpyrrolidone 10-5 10--[Solubilizing agent]-3-methyl-3-methoxybutanol 100 50 50 370 50 50 [pH buffer]-Primary ammonium citrate 25 25 25 25 25 25-Phosphorus Acid (85%) 10 10 10 10 10 10 ・ Ammonium nitrate 10 10 10 10 10 10 (rust inhibitor) ・ Benzotriazole 0.1 0.1 0.1 0.1 0.1 0.1 [Water-soluble polymer compound] ・ Hydroxypropylcellulose 55-55--PVA / maleic anhydride copolymer--5--5 [Preservative]-4-isothiazoline-1 2 2 12-3-one derivative • 1,1-dibromo-1-nitro-1--1-2-2-2-ethanol The total volume was adjusted to 1000 ml with pure water. ────────────────────────────────────

[0029]

Embedded image

The prepared fountain solution compositions of Examples 1 to 3 and Comparative Examples 1 to 3 were diluted to a concentration of 2%, and the pH was adjusted to 5.0 ± 0.3 with the 2% diluted solution. did. Using these diluents, using a diamond water supply system of Mitsubishi Printing Machine Co., Ltd., using a high-purity MZ cyan ink of Toyo Ink Co., Ltd. and a plate made of VPS manufactured by Fuji Photo Film Co., Ltd. under standard conditions as a plate to be used. A print test was performed. Table 2 shows the evaluation results at that time. The details of the evaluation are described below.

(A) Metering Roll Soil: The degree of ink stain on the metering roll for watering was examined. Good A Somewhat inferior B Inferior C (b) Bleedability: After printing 5,000 and 10,000 sheets, the operation of the printing press was stopped, and the extent to which the ink in the image area had spread to the non-image area was examined. Almost no bleeding A A little bleeding B Many bleeding C

(C) Emulsifiability: When printed on 10,000 sheets,
The emulsified state of the ink on the ink kneading roll was examined. Good A Somewhat bad B Bad C (d) Continuous stability: Using fresh water as dampening water, 1000
Print 0 sheets, find the amount of dampening water that does not cause stains (minimum water level), print using various dampening water with this minimum water level, and print until stains occur on the printed matter The judgment was made based on the number of sheets. 10,000 sheets or more A 10,000 to 3000 sheets B (e) Suitability of rib mark (easiness of formation of rain streaks): The solid portion and the flat net portion were observed at a printing press speed of 100,000,000 rpm and 5000 rpm. Good A Somewhat inferior B Inferior C

[0033]

Table 2 Example Comparative Example 1 2 3 1 2 3 (a) Metering roll stain AAACCB (b) Ink bleed AAACBB (c) Emulsifiable AAACAB (d) Continuous stability AAACBC (e) Rib mark suitability AAACBB ──────────────── ────────────────────

The fountain solution of the present invention was excellent in all of the items (a) to (e), and it was found that a good printed matter was obtained and the suitability for the fountain solution was also excellent.

Claims (1)

[Claims] 1. A fountain solution for a lithographic printing plate comprising at least one compound represented by the following general formula (I) or (II) and a compound represented by the following general formula (III): Composition. Embedded image (Wherein, R ¹ represents a hydrogen atom or an alkyl group having 1 to 8 carbon atoms, R ² represents a hydrogen atom or a methyl group, m represents an integer of 1 to 4, and R ³ represents a hydrogen atom or a carbon atom. 1 atom
~ 12 alkyl groups, n, o and p each represent 1
And R ⁴ represents an alkyl group having 2 to 12 carbon atoms. )