JP2001105764A - Dampening solution composition for lithographic printing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a dampening water composition for lithographic printing, which accelerates no flowing-out of calcium from an ink or a paper, exhibits a favorable calcium hiding effect, prevent the calcium from being precipitated onto the roller of a printing machine over a longer term and, at the same time, prevent also a tinting from developing, resulting in showing a favorable printability. SOLUTION: This dampening water contains a hydrophilic film forming agent, at least one kind of an emulsification inhibitor selected form the group consisting of acetylene glycols and acetylene alcohols and an organic phosphonic acid.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a dampening solution used for offset printing of a lithographic printing plate.

[0002]

2. Description of the Related Art A printing plate in lithographic printing has an image area formed on the plate with an oil-sensitive resin having an affinity for an oil-based ink, and has an affinity for water, which repels the oil-based ink. It has a non-image portion formed of a hydrophilic layer. In lithographic printing, due to such a difference in characteristics between the image area and the non-image area, the ink supplied to the plate surface by the ink supply roller is directed to the image area, and the dampening water supplied by the dampening water supply roller is directed to the non-image area. Because of the transfer, printing on the same plane is possible.

[0003] The hydrophilic non-image portion is a hydrophilic layer formed of gum arabic or the like adsorbed by an operation such as gumming performed before printing. During printing, the plate surface of the printing plate is constantly subjected to friction of a roller or a blanket, and the hydrophilic layer is easily damaged due to the influence of paper powder or a coating agent on printing paper. Therefore, in order to perform printing while repairing the damaged hydrophilic layer, a hydrophilic film forming agent is usually added in advance to the component of the dampening solution.

However, the hydrophilic film-forming agent in the fountain solution easily reacts with calcium to form a precipitate, and if the precipitate adheres to a water source roller of a printing press, it causes poor drainage or uneven water. It is known that this causes printing trouble. For this reason, using a water softening device, a water softening treatment is carried out in which measures are taken in advance to reduce the calcium concentration of the water used, or a chelating agent such as EDTA is added to the dampening water as a calcium concealing agent. .

[0005]

However, the use of a water softener is not only disadvantageous in terms of cost, but also has no effect on calcium eluted from ink or printing paper into dampening water. On the other hand, a method of adding a chelating agent to a fountain solution as a calcium concealing agent is disclosed in JP-A-11-10544.
9, which is disclosed in Japanese Patent Application Laid-Open No. Hei 4-235096, and has an effect of preventing precipitation of calcium eluted from ink or paper, but calcium concealing agents used so far dissolve calcium salts. Because of its high ability, it showed an effect of suppressing the precipitation of calcium salts. Therefore, these calcium concealing agents tend to promote the elution of calcium from paper or ink. For this reason, a good calcium hiding effect is exhibited immediately after the start of use of the dampening solution, but the calcium concentration in the dampening solution increases as it is used, so that precipitation on the head roller of the printing press is prevented for a long time. Could not.

As another problem, a fountain solution simply subjected to a softening treatment may be easily emulsified with ink. When printing is performed using such a fountain solution, there is a problem that ink is easily eluted into the fountain solution, so that bleeding occurs at the boundary between the image portion and the non-image portion, that is, so-called floating stain easily occurs. .

[0007] The present invention solves these problems, does not promote the dissolution of calcium from ink or paper, exhibits a good calcium concealing effect, and prevents precipitation on printing press rollers for a long period of time. Another object of the present invention is to provide a fountain solution composition for lithographic printing which prevents the occurrence of floating stains and exhibits good printability.

[0008]

Means for Solving the Problems In order to achieve the above object, conventionally used calcium concealing agents promote the elution of calcium from paper and ink, and increase the calcium concentration in the fountain solution, Since precipitation cannot be prevented for a long period of time, the use of a calcium concealing agent that has not been used conventionally and the use of dampening water that has only been subjected to a soft water treatment easily emulsify with the ink, so that so-called floating stains are generated. This problem is solved by using an emulsification inhibitor in combination, and the present invention provides a hydrophilic film-forming agent and at least one emulsification inhibitor selected from acetylene glycols and acetylene alcohols, and an organic phosphonic acid. It is characterized by containing.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail. An organic phosphonic acid is added to the fountain solution composition of the present invention as a calcium concealing agent. In particular, it is preferable to use 1-hydroxyethane-1,1-diphosphonic acid and a compound represented by the following general formula (I). General formula (I)

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The following are specific examples of the organic phosphonic acid used in the fountain solution composition of the present invention, but the present invention is not limited to these compounds.

[0011]

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Among these compounds, 1-hydroxyethane-1,1-diphosphonic acid represented by Chemical Formula 3, Chemical Formula 5, Chemical Formula 6, or Chemical Formula 11 masks calcium without promoting calcium elution from paper or ink. It is particularly excellent in performance and is particularly preferably used in the fountain solution composition of the present invention.

The fountain solution of the present invention contains at least one of these compounds, and is preferably contained so that the total amount thereof is 0.01 g to 1.0 g per liter of working solution. Especially 0.025 g to 0.5 per liter
By dissolving calcium more than necessary by containing it in the range of g, it is possible to sufficiently hide the eluted calcium ions, and even if the number of sheets passed through becomes large, dirt adheres to the water supply roller. Does not adversely affect the rising of the water. When more than 1.0 g is added per liter, these compounds affect the calcium ions in the ink, which tends to cause a deterioration in the fluidity of the ink and a change in the color tone. It is difficult to print on a paper.

The fountain solution composition of the present invention contains at least one compound selected from acetylene glycols and acetylene alcohols as an emulsifier. Specific compounds include 3,5-dimethyl-1-hexyne-3
-Ol, 2,4,7,9-tetramethyl-5-decyne-4,7-diol, propargyl alcohol (2-propyn-1-ol), 3-butyn-1-ol, 1-
Butyn-3-ol, 2-butyne-1,4-diol,
3,6-dimethyl-4-octyne-3,6-diol,
Is mentioned. In particular, 3,5-dimethyl-1-hexyne-
3-ol, 2,4,7,9-tetramethyl-5-decyne-4,7-diol has a high ink emulsification suppressing effect,
It can be preferably used. By including the total amount of these emulsification inhibitors in an amount of 0.01 g to 1.0 g per liter of the working solution, the elution of the ink into the dampening water can be suppressed even in the dampening water to which the organic phosphonic acid is added. And the occurrence of floating dirt can be prevented.

As the hydrophilic film forming agent of the fountain solution of the present invention, a hydrophilic polymer compound is preferably used. Specific compounds include carboxymethylcellulose (CM
C), gum arabic, starch derivatives (dextrin, enzyme-modified dextrin, pregelatinized starch, phosphate starch, carboxymethyl starch, hydroxyalkyl starch, etc.),
Fiber derivatives (carboxyethylcellulose, methylcellulose, hydroxypropylmethylcellulose, hydroxyethylmethylcellulose, etc.), sodium alginate, propylene glycol alginate and the like can be mentioned. Particularly preferable printability can be obtained by combining at least one of these compounds and using a compound having a viscosity of 1.05 cSt to 3.00 cSt.

Further, among these hydrophilic polymers, most preferred are gum arabic, CMC and hydroxypropyl methylcellulose, and the total amount of these compounds is 0.005 to 0.005 in the fountain solution of the present invention. 0.05% by weight
By containing it, the viscosity can be adjusted in the range of 1.05 cSt to 3 cSt, and good printability is exhibited. When the content of the hydrophilic film-forming agent is 0.005% by weight or less, the dampening solution has a low viscosity and the running-up during printing is poor, so that sufficient dampening solution cannot be supplied to the plate surface. On the other hand, 0.05
If it is contained in an amount of not less than% by weight, emulsification of the ink proceeds during printing, causing bleeding of the ink and the like, which adversely affects the print quality.

The fountain solution of the present invention may be used to increase the viscosity of the fountain solution so as to improve the water level of the water supply opening, to lower the surface tension to improve the wetting, and to increase the emulsification speed to stabilize the printing density. IPA can be added for the purpose. Even if some dirt adheres to the water supply roller due to the addition of IPA, there is a tendency that the rise in water is compensated for and the printing trouble is reduced. However, the use of IPA is not preferred in the work environment, and various IPA substitutes have recently been proposed. When these IPA substitutes are used, the water supply roller tends to be poorly drained as soon as the water supply roller becomes dirty. Since the dampening solution of the present invention has an excellent effect of preventing contamination of the roller, printing trouble hardly occurs even when these IPA substitutes are used.

Solvents such as glycols can be used as the IPA substitute substance. Specific examples preferably used are ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, and the like.
Dipropylene glycol, tripyrylene glycol,
Ethylene glycol methyl ether, ethylene glycol ethyl ether, ethylene glycol propyl ether, ethylene glycol butyl ether, diethylene glycol methyl ether, diethylene glycol ethyl ether, diethylene glycol propyl ether, diethylene glycol butyl ether, propylene glycol methyl ether, propylene glycol ethyl ether, propylene glycol propyl ether, propylene Glycol butyl ether, dipropylene glycol methyl ether, dipropylene glycol ethyl ether, dipropylene glycol propyl ether, dipropylene glycol butyl ether, and the like.

In the fountain solution of the present invention, organic acids, inorganic acids and salts thereof can be used. These act as a pH buffer for the dampening solution, and also have the effect of preventing fatty acids and the like dissolved from the ink from adhering to the non-image areas to become oil-sensitive, thereby effecting appropriate etching of the plate surface. Specific organic acids include citric, ascorbic, malic, tartaric, formic, propionic, succinic, glutaric, maleic, fumaric, malonic, lactic, acetic, gluconic, oxalic, and organic phosphonic acids. Acids and the like. Examples of the inorganic acid include phosphoric acid, nitric acid, sulfuric acid, polyphosphoric acid and the like, and these are favorably used as alkali metal salts, ammonium salts and the like. It is also desirable to add organic amines to enhance these effects.

It is also desirable to add a surfactant or the like to the fountain solution of the present invention in order to improve the emulsion stability and wettability and to suppress a decrease in the oil sensitivity of the image area due to the addition of a hydrophilic film-forming agent. Thereby, the generation of stains is small, good oil sensitivity is maintained, and a stable print density is maintained. As the surfactant, a polyoxyethylene polyoxypropylene block polymer or a polyoxyethylene polyoxypropylene alkyl ether is preferably used. Specifically, Adecapluronic L-31, L-44, L-44 manufactured by Asahi Denka Co., Ltd.
Adecapluronics (“ADEKA” is a registered trademark) such as 62 and P-84;
0, 485, 785, etc. ("Epan" is a registered trademark), Nikko Chemical's Nikkor PBC-31, P
Nikkor PBCs ("Nikkor" is a registered trademark) such as BC-34, PBC-41, and PBC-44.

It is also desirable to add a preservative to the fountain solution of the present invention. Since the hydrophilic polymer in the fountain solution is gradually decomposed under the influence of the living organism and the viscosity gradually decreases, it is preferable to add a preservative or an antifungal agent, specifically, salicylic acid,
Phenol, phenol butyl butyl parabenzoate, sodium dehydroacetate, 4-isothiazolone 3-one, 1,2-
And benzisothiazolin-3-one.

It is also desirable to add a rust inhibitor to the fountain solution of the present invention. The rollers of the printing press are always affected by the dampening solution. In order not to damage the printing machine even by long-term use, it is preferable to use a rust inhibitor, specifically, nitrate,
Salts of amines, 1H-benzotriazole and the like can be mentioned.

The fountain solution of the present invention is used for transportation and management.
It is desirable to supply as a concentrated solution of up to 1000 times.

[0024]

Next, the present invention will be described in detail with reference to examples. The following two types of fountain solution compositions (A) and (B) were used as basic compositions, and the compounds shown in Table 1 were added thereto, and Examples 1 to 3 and 7 to 9 and Comparative Examples 4 to 6 were used. 10-11
The fountain solution was adjusted.

<Dampening solution composition (A)> Water 700 ml Carboxymethyl cellulose 0.4 g Surfactant (Epan 785: manufactured by Dai-ichi Kogyo) 0.4 g Emulsifier (see Table 1) 0.05 g Citric acid 0.85 g KOH 0.25 g Magnesium nitrate 0.04 g Ca concealing agent (see Table 1) 0.1 g 1,2-Benzisothiazolin-3-one 0.1 g Water was added and adjusted to pH = 4.0 with 1000 ml KOH.

<Dampening solution composition (B)> Water 700 ml Ethylene glycol monobutyl ether 5.0 g Hydroxypropyl methylcellulose 0.1 g Surfactant (ADEKA PLURONIC L-31: manufactured by Asahi Denka) 0.3 g Emulsifier (Table 1) 0.2 g citric acid 0.1 g KOH 0.03 g ammonium nitrate 0.4 g Ca concealing agent (see Table 1) 0.1 g 1,2-benzisothiazolin-3-one 0.1 g Water is added and pH is adjusted with 1000 ml KOH. = Adjusted to 4.0.

Using the dampening solutions of Examples and Comparative Examples adjusted as described above, a printing test of 50,000 sheets was conducted using a Mitsubishi printing press diamond water supply apparatus, and the contamination of the water supply roller and the printing material were evaluated. The occurrence of floating dirt was observed and evaluated.

Stain on water supply roller: ：: No deposits are generated at all even after printing 50,000 sheets. Δ: A small amount of precipitate was observed when 50,000 sheets were printed. ×: Staining was observed after about 5,000 sheets were printed.

Floating dirt: ：: No bleeding even after printing 5,000 sheets. X: Bleeding was observed from the time when about 1,000 sheets were printed.

[0030]

[Table 1] Emulsifier (a): 2,4,7,9-tetramethyl-5
-Desine-4,7-diol emulsifier (b): 3,5-dimethyl-1-hexyne-
3-ol

As shown in Table 1, when printing was performed using the fountain solution of the present invention, even if 50,000 sheets were printed, no stain was attached to the water supply roller. In addition, printing could be performed with good printability without any floating stains. On the other hand, when the dampening solutions of Comparative Examples 4, 6, and 12 were used, dirt was recognized on the water supply roller from the time when about 5,000 sheets were printed, and the drainage became uneven, and the dirt also appeared on the printed matter. Were seen, and it was not suitable for further printing. When the dampening solutions of Comparative Examples 5 and 11 were used, no stain was observed on the water supply roller, but the boundary between the image area and the non-image area was blurred, and it was not possible to continue to produce high-quality printed matter.

[0032]

As described above, according to the first aspect of the present invention, a hydrophilic film-forming agent, at least one emulsification inhibitor selected from acetylene glycols and acetylene alcohols, and an organic phosphonic acid are contained. Therefore, the combined action of the chelating agent and the emulsification inhibitor does not promote the elution of calcium from the ink or paper, and has a good calcium concealing effect. In addition to preventing the contamination due to the precipitation of the ink over a long period of time, the effect of suppressing the emulsification of the ink can prevent the occurrence of the floating contamination of the printed matter, so that printing can be performed while maintaining appropriate printing adequacy over a long period of time.

According to the second aspect of the present invention, the emulsification inhibitor is 3,5-dimethyl-1-hexyn-3-ol and / or 2,4,7,9-tetramethyl-5-decyne- Since 4,7-diol is used, the effect of suppressing the emulsification of the ink is higher, and the occurrence of floating stains can be more effectively prevented.

According to the third aspect of the present invention, since the organic phosphonic acid is a compound represented by the following general formula (I), it does not promote calcium elution from paper or ink. Since the calcium concealing effect is more excellent, it has an effect that precipitates are less likely to be generated, so that it is possible to perform printing while maintaining appropriate printing suitability for a longer period. (General formula I)

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According to the fourth aspect of the present invention, since the organic phosphonic acid is 1-hydroxyethane-1,1-diphosphonic acid, calcium elution from paper or ink is not promoted. Since the calcium concealing effect is more excellent, it has an effect that precipitates are less likely to be generated, so that it is possible to perform printing while maintaining appropriate printing suitability for a longer period.

Claims (4)

[Claims] 1. A fountain solution composition for lithographic printing, comprising a hydrophilic film-forming agent, at least one emulsification inhibitor selected from acetylene glycols and acetylene alcohols, and an organic phosphonic acid. 2. The method according to claim 1, wherein the emulsifier is 3,5-dimethyl-1-hexyn-3-ol and / or 2,4,7,9-tetramethyl-5-decyne-4,7-diol. The fountain solution composition for lithographic printing according to claim 1. 3. The fountain solution composition for lithographic printing according to claim 1, wherein the organic phosphonic acid is a compound represented by the following general formula (I). (General formula I) 4. The fountain solution composition for lithographic printing according to claim 1, wherein the organic phosphonic acid is 1-hydroxyethane-1,1-diphosphonic acid.