JPH10337975A - Dampening water composite for lithographic printing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform stable lithographic printing undergoing no fouling, roller separation, or the like even in use for a long period of time by adding a compound expressed by specific formulas. SOLUTION: Contained herein is a compound shown by formulas I, II, wherein R1 R2 indicate a 1-4C hydrocarbon group, and (n) expresses 1-3 integer numbers. The compound is generally called as alkyl ether of alkyl glycol in its chemical name, and for R1 , R2 , a methyl group, an ethyl group, an isopropyl group, a butyl group are used often. Although there is limitation of an additive, in particular, for such a compound indicated by formulas I and II, moisture water is preferable to be 0.05-10 wt.%, and more preferably to be 0.1-5 wt.%. In addition, as an auxiliary component for further lowering the surface tension of moisture water, a water soluble organic solvent can be added as required. As such a water soluble organic solvent, a multivalent alcoholic group such as 3-methyl 3-methoxybutanol, and alkylpyrolidone are suitable particularly. There is no limitation for the loadings, however, 0.1-5 wt.% is suitable therefor.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a fountain solution composition useful for lithographic printing.

[0002]

2. Description of the Related Art Lithographic printing is a printing method in which printing is performed using a printing plate having a portion corresponding to an image portion as a grease-sensitive surface and a portion corresponding to a non-image portion as a hydrophilic surface. That is, the ink is attached to the oil-sensitive surface, the fountain solution is attached to the hydrophilic surface, and printing is performed using the mutual repulsion between the ink and the fountain solution. At this time, it is important to supply the ink and the fountain solution to the plate surface in an appropriate balance. If the fountain solution is applied too much, the emulsification of the ink becomes severe and transfer failure occurs. On the other hand, if the fountain solution is too small, the ink adheres to the non-image area and becomes dirty.

In recent years, in lithographic printing, high-speed and automation of a printing press have required high quality and stability of a printed material, and a continuous water supply system is becoming mainstream in such a situation. But,
This continuous water supply system is designed on the assumption that isopropyl alcohol (IPA) is used as a dampening solution in order to exhibit its performance. This IPA is classified as dangerous substance Class 4 alcohols, and it is necessary to pay close attention to fire. Under such a social environment, a fountain solution for lithographic printing which can replace IPA has been developed. For this purpose, for example, Japanese Patent Publication No. 55-19775 and Japanese Patent Laid-Open No. 63-25
In JP-A-0996 and JP-A-3-63188, various surfactants and alcohol derivatives are used. These fountain solutions (compositions) are provided with fountain solution properties similar to IPA in terms of their surface tension, viscosity and emulsification suitability. The rise is poor, and the uniform wetting of the hydrophilic non-image area of the plate is insufficient, so that the water width becomes narrow, and a serious problem such as dirt and roller peeling occurs particularly in a long run.

Although the use of a dampening solution containing a dampening solution composition which is said to be able to reduce IPA in recent years has a certain effect of reducing IPA, the excellent dynamic surface tension lowering action of IPA is obtained. Hardness and softness, such as penetrating action, wettability, emulsification suitability, defoaming properties, etc., could not be completely covered, and ceramicization of the dumper roller of the printing machine, change of rubber roller, adjustment of roller nip, etc. Support is needed. The IPA reduction effect can be realized only after adjusting these conditions, but the problem of dirt and roller bale still occurs during long-term continuous operation. Therefore, a fountain solution that can be stably printed without generating roller baldness or dirt is desired.

[0005]

SUMMARY OF THE INVENTION The present invention provides a fountain solution composition for lithographic printing which is excellent in printing aptitude and can realize stable lithographic printing without generation of stains and roller peeling even after long-term use. Is what you do.

[0006]

Means for Solving the Problems The first invention is a fountain solution composition for lithographic printing characterized by containing a compound represented by the general formula (A) and / or (B). General formula (A) R ₁ —O— (CH ₂ CH ₂ O) n—R ₂ General formula (B) R ₁ —O— (CH ₂ CHCH ₃ O) n—
In the formula R ₂ , R ₁ and R ₂ represent a hydrocarbon group having 1 to 4 carbon atoms. n
Represents an integer of 1 to 3. The second invention is the fountain solution composition for lithographic printing according to the first invention, which comprises at least one compound selected from the group consisting of a water-soluble polyhydric alcohol, ether and alkylpyrrolidone.

In the present invention, the fountain solution composition for lithographic printing is a concentrated solution comprising the compound represented by the general formula (A) and / or (B) and water, and further diluted with water to the concentration used for printing. Means what was done. If necessary, the fountain solution composition for lithographic printing may contain other known auxiliary substances for improving printability.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The compound represented by the general formula (A) and / or (B) has a chemical name generally referred to as a dialkyl ether of an alkylene glycol. For example, R ₁ and R ₂ represent a methyl group or an ethyl group. , An isopropyl group and a butyl group are preferably used. The amount of the compound represented by the general formula (A) and / or (B) is not particularly limited, but is preferably 0.05 to 10% by weight as a fountain solution.
More preferably, it is 0.1 to 5% by weight. If the concentration is less than 0.05% by weight, the water may not be sufficiently drained and the effect of preventing contamination may not be sufficiently exhibited. If the concentration is more than 10% by weight, it may cause cost problems and adversely affect printability. Is not preferred.

Further, a water-soluble organic solvent can be added, if necessary, as an auxiliary component for further reducing the surface tension of the dampening solution. Examples of the water-soluble organic solvent include polyhydric alcohols such as propylene glycol,
Particularly preferred examples include ethers such as methyl-3-methoxybutanol, monoalkyl ethers of mono- or polyethylene glycol, mono-alkyl ethers of mono- or polypropylene glycol, and alkylpyrrolidone. The amount of addition is not particularly limited, but is not limited to 0.1.
1-5% by weight is preferred.

In the composition for fountain solution of the present invention, gum arabic, dextrin, sodium alginate, carboxymethylcellulose, carboxyethylcellulose, hydroxymethylcellulose, polyvinylpyrrolidone, polyvinylalcohol are further used as desensitizing agents for protecting the plate surface. And water-soluble polymer compounds such as polyacrylic acid and polyacrylamide, and polyphosphoric acid and phytic acid. In addition, inorganic or organic acids such as nitric acid, sulfuric acid, phosphoric acid, citric acid, acetic acid, and tartaric acid, and their sodium salts, potassium salts, and magnesium salts can be added as pH adjusters. In addition, chelating agents, rust preventives, anionic, cationic, nonionic surfactants, and wetting agents such as tridecanol and glycerin can also be added.

As preservatives other than the present invention, for example, salicylic acid, formalin, phenolic compounds, benzimidazole and benzothiazole compounds, organic nitrogen halogen compounds, organic nitrogen sulfur compounds, organic sulfur halogen compounds, organic cyano halogen compounds It can also be used in combination with a system compound, methylene bisthiocyanate, 3-isothiazolone, dithiol, bromoacetic acid esters and the like. The composition for a fountain solution of the present invention comprises water, a general formula (A)
And / or mixing the compound represented by (B) at a predetermined ratio, and then mixing the water-soluble polymer, acid, salt, surfactant,
What is necessary is just to add a surface tension reducing agent, a pH adjuster, a rust inhibitor, a wetting agent, a preservative, and a chelating agent, mix and stir to obtain a uniform aqueous solution. In addition, water containing a water-soluble polymer, an acid, a salt, a surfactant, a surface tension reducing agent, a pH adjusting agent, a rust inhibitor, a wetting agent, a preservative, and a chelating agent may be mixed with water of the general formula (A) and / or (B). ) May be added and mixed and stirred,
The method of mixing and stirring is not particularly limited. The fountain solution of the present invention is obtained by mixing a concentrated solution of the fountain solution of the present invention with water at a predetermined ratio.

Hereinafter, the present invention will be described in more detail based on embodiments.

[0013]

EXAMPLE 77 parts by weight of water, 1 part by weight of phosphoric acid, 1 part by weight of magnesium nitrate, 1 part by weight of carboxymethyl cellulose,
An etch stock solution for fountain solution comprising 1 part by weight of a nonionic surfactant is prepared. A fountain solution composition containing the compound represented by the general formula (A) and / or (B) according to the present invention is prepared according to the following formulation. Example 1 98 parts by weight of water 1 part by weight of an undiluted solution for fountain solution 1 part by weight of ethylene glycol dimethyl ether 1 part by weight of 98 parts by weight of water for fountain solution 1 part by weight of undiluted solution for fountain solution 1 part by weight of diethylene glycol dimethyl ether 1 part by weight of Example 3 98 parts by weight of water Stock solution for fountain solution 1 part by weight Triethylene glycol dimethyl ether 1 part by weight Example 4 98 parts by weight of water Stock solution for fountain solution 1 part by weight 1 part by weight of diethylene glycol diethyl ether 1 part by weight Example 5 98 parts by weight of water for fountain solution Undiluted solution 1 part by weight Diethylene glycol dibutyl ether 1 part by weight Example 6 98 parts by weight of water Undiluted solution for fountain solution 1 part by weight 1 part by weight of dipropylene glycol dimethyl ether 1 part by weight Example 7 98 parts by weight of undiluted solution for fountain solution 1 part by weight of di Propylene glycol dimethyl acetate Ter 0.5 parts by weight Diethylene glycol dibutyl ether 0.5 parts by weight Example 8 98 parts by weight of water 1 part by weight of a stock solution for fountain solution 1 part by weight 0.5 parts by weight of dipropylene glycol dimethyl ether 0.5 parts by weight of dipropylene glycol monomethyl ether Example 9 98 parts by weight of water 1 part by weight of a stock solution for fountain solution 1 part by weight of tripropylene glycol dimethyl ether 1 part by weight of Example 10 98 parts by weight of a stock solution for etchant for fountain solution 1 part by weight 0.5 part by weight of dipropylene glycol dimethyl ether 3-methyl 0.5 parts by weight of -3-methoxybutanol

A fountain solution composition is prepared according to the following formulation as a comparative example. Comparative Example 1 96 parts by weight of water Undiluted solution for fountain solution 1 part by weight 3 parts by weight of isopropyl alcohol Comparative Example 2 98 parts by weight of undiluted solution for fountain solution 1 part by weight 0.5 parts by weight of dipropylene glycol monomethyl ether 0.5 parts by weight 3-methyl -3-Methoxybutanol 0.5 parts by weight Comparative Example 3 Water 99 parts by weight Etch stock solution for dampening water 1 part by weight

The fountain solution compositions of Examples 1 to 10 and Comparative Examples 1 to 3 are used as fountain solutions for the following experiments. Experiment (printing test) A printing test was performed using the dampening solution compositions of Examples 1 to 10 and Comparative Examples 1 to 3 under the following conditions. Table 1 shows the results. (Conditions for printing test) Using a sheet-fed offset printing press,
A total of about 10,000 prints were made at a print speed of 10,000 prints / hour.

Experimental procedure: After taking out the OK sheet, continuous printing was performed for 8,000 sheets. After confirming the printability by the presence or absence of roller baldness and dirt, the water dial was gradually lowered, and the dial value at the time when dirt was generated was regarded as the dirt limit. . Finally, the degree of entanglement of the ink with the water base rubber roll was confirmed. Evaluation criteria: 1) Printability: The presence or absence of peeling of the ink roller of the inking roll of the printing press was visually observed. Also, visually observe the sampled printed matter for entanglement or soiling. 2) Print density measurement: Using the solid red density of the OK sheet as the reference density, comparing the red solid density value and the amount of change after printing 8000 sheets. Those with little change in density are judged to be good. 3) Ink entanglement of the water roll: The degree of entanglement of the ink with the water roll after the end of the experiment was visually evaluated. Those with little ink entanglement are judged to be good.

Evaluation 1: No entanglement 2: Slight entanglement 3: Medium entanglement degree 4: Severe entanglement 4) Soil water dial value: The lower the dial value, the smaller the amount of water to be raised, and the higher the amount of dirt. to decide. Water dial width 0-100

[0018]

[Table 1]

[0019]

As described above, even if it does not contain an alcohol-based substance such as IPA, the effect that the printability and the quality of printed matter are greatly improved as compared with the conventional fountain solution is recognized.

Claims (2)

[Claims] 1. A fountain solution composition for lithographic printing, comprising a compound represented by the general formula (A) and / or (B). General formula (A) R ₁ —O— (CH ₂ CH ₂ O) n—R ₂ General formula (B) R ₁ —O— (CH ₂ CHCH ₃ O) n—
In the formula R ₂ , R ₁ and R ₂ represent a hydrocarbon group having 1 to 4 carbon atoms. n
Represents an integer of 1 to 3. 2. The fountain solution composition for lithographic printing according to claim 1, comprising at least one compound selected from the group consisting of water-soluble polyhydric alcohols, ethers and alkylpyrrolidones.