JP2002144752A - Damping water composition for lithographic printing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide damping water for printing which is applicable to various kinds of printing materials without the necessity to change the damping water in compliance with the printing material and is best suited to working environments, and further, free from a printing trouble. SOLUTION: This damping water for lithographic printing contains at least one kind selected from chemical compounds represented by formulae (I), (II) and (III).

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, on the plate, an image portion having an affinity for oil-based ink and a non-image portion repelling the oil-based ink but having an affinity for water. . 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. Therefore, in order to obtain good printed matter, the ink is sufficiently applied to the image portion, but it is desirable that the non-image portion does not accept the ink at all. Therefore, the lipophilicity and hydrophilicity of the image portion and the non-image portion are required. The difference must be large enough. For this reason, various desensitizing treatments according to the plate material, the printing machine, and the printing method to be used are being studied.

As a printing plate generally used in lithographic printing, a PS plate using aluminum as a support, a plate material utilizing a silver salt diffusion transfer method, and the like are known. These plate materials are used according to the purpose of printing in accordance with their respective characteristics. For example, if the number of printed sheets is large, use a PS plate having excellent printing durability, and if the number of printed sheets is small, use a printing plate by the silver salt diffusion transfer method, which is not strong but has low printing durability. As described above, it is common practice to change the used plate material in accordance with the purpose of printing.

[0004]

However, if the same dampening solution is used for different types of plate materials, various problems occur. For example, in a silver salt diffusion transfer printing plate, the difference between the lipophilicity of the image area and the hydrophilicity of the non-image area is not as large as that of the PS plate. When the supply of dampening water becomes unstable due to stains or the like, so-called “ground stains” in which ink adheres to non-image portions during printing are likely to occur. Usually, in order to prevent such a problem from occurring, a method of adding inorganic fine particles such as colloidal silica to a dampening solution for a silver salt diffusion transfer printing plate to increase the hydrophilicity of the plate surface is used. . When the fountain solution for the silver salt diffusion transfer printing plate is used for printing the PS plate, the lipophilicity of the image portion of the PS plate is reduced due to the influence of the inorganic fine particles, and it becomes difficult for the ink to get on the board surface, so that the printing quality is reduced. Cause it.

The dampening solution containing the inorganic fine particles is P
Since it is unsuitable for printing on the S plate, fountain solution for the PS plate generally contains carboxymethylcellulose, hydroxyethylcellulose, or the like as a hydrophilizing agent. However, when such a fountain solution for a PS plate is used for printing on a silver salt diffusion transfer printing plate, there is a problem that a sufficient desensitizing effect cannot be obtained and background stains are easily generated.

Although a fountain solution dedicated to the plate material is generally used in accordance with the plate material to be used as described above, both the cellulose and the inorganic fine particles are used in combination, and depending on the plate material to be used. There has also been proposed a dampening solution that can be used for both the PS plate and the silver salt diffusion transfer printing plate by changing the dilution ratio. In the case of this common dampening solution, it is necessary to use it at a dilution rate according to the plate material in order to avoid the above-mentioned adverse effects. This means that when used for printing on PS plates, it is necessary to adjust the dampening solution to be thinner than when using for printing plates using the silver salt diffusion transfer method so as not to be adversely affected by the added inorganic fine particles. This is because Therefore, when it is desired to use both types of printing plates with one printing press, it is necessary to replace the dampening solution each time the printing plates are replaced with different types of printing plates, and there has been a demand for improvement in terms of work efficiency.

A first object of the present invention is to provide a common dampening solution which is compatible with various plate materials and does not require any replacement of the dampening solution even in a printing environment where plate materials are mixed. .

Another problem is that isopropyl alcohol (IPA), which is usually added to fountain solution, is environmentally undesirable. In order to prevent problems such as background stains that occur during printing, it is not enough that a suitable hydrophilizing agent is added to the fountain solution, and this hydrophilizing agent should be sufficiently spread over the plate surface during printing. Is required. For this reason, for the purpose of facilitating spreading of dampening water on the plate,
A method is often employed in which PA is added to dampening water to make the board surface easier to wet. However, IPA has a low boiling point, is easily evaporated, and is a second type organic solvent in the Prevention Regulations for Organic Solvents.
In the usual use method of adding, it is necessary to install a device for improving the working environment.

A second object of the present invention is to enable printing using various plate materials without causing printing troubles such as background contamination without using an organic solvent such as IPA which is not preferable in a working environment. To provide a common dampening solution.

[0010]

Means for Solving the Problems The above object is achieved by the following constitution. That is, the present invention relates to the following general formulas (I) (Chem. 6), (II) (Chem. 7) and (III) (Chem. 8)
A fountain solution composition for lithographic printing, characterized by containing at least one compound selected from the compounds represented by the formula: General formula (I)

Embedded image a, b, d, and e represent an alkylene chain having 1 to 10 carbon atoms, and these a, b, d, and e may be substituted with a hydroxyl group, and have an ether bond or a polyethylene oxyhaside having a polymerization degree of 5 to 20. May be included. A, b,
d and e may be the same or different, respectively. X and Y represent any of a hydrogen atom, a hydroxyl group, a carboxyalkyl group, a sulfoalkyl group, and a hydroxyalkyl group, and X and Y may be the same or different. General formula (II)

Embedded image General formula (III)

Embedded image n = an integer of 5 to 10000 In the general formulas (II) and (III), R ₁ , R ₂ , R ₃
May be the same or different, and represent a hydrogen atom or the following formula (Formula 9). F represents an alkylene group having 2 to 10 carbon atoms, and these alkylene groups may be substituted with a hydroxyl group, and may have an ether bond or a polymerization degree of 5 to 30.
May contain a polyethyleneoxy group. g, h,
i represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, which may be the same or different.

Embedded image

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail. Specific examples of the compound represented by the general formula (I) include the following. (I-1)

Embedded image (I-2)

Embedded image (I-3)

Embedded image (I-4)

Embedded image (I-5)

Embedded image (I-6)

Embedded image (I-7)

Embedded image (I-8)

Embedded image (I-9)

Embedded image (I-10)

Embedded image (I-11)

Embedded image

The compounds represented by the general formula (I) can be easily synthesized by subjecting a commercially available product to a polyamine by a polyaddition reaction between a primary amine and a diglycidyl compound.

As the compound represented by the general formula (II) or (III), those having an introduction rate of the following formula (Chemical Formula 21) of 0.001 to 2 per basic glucose chemical structure can be particularly preferably used. .

Embedded image Specific examples of these compounds include, for example, the following. (II-1)

Embedded image In the formula, among R, 0.005 to 0.05 mol with respect to n represents the following formula (Formula 23), and the rest represents H. And m is 1
Represents an integer of 10.

Embedded image (II-2)

Embedded image In R in the formula, 0.005 to 0.05 mol with respect to n represents the following formula (Formula 25), and the rest represents H.

Embedded image (II-3)

Embedded image In the formula, among R, 0.005 to 0.05 mol with respect to n represents the following formula (Formula 27), and the rest represents H.

Embedded image

The compounds represented by the general formulas (II) and (III) are commercially available as cationic cellulose or cationic starch. Specifically, Lion Corporation provides the “Leoguard” series (“Leoguard”). Is a registered trademark of Lion Co., Ltd.), and “Petrosize” series (“Petrosize” is a registered trademark of Nichiten Chemical Co., Ltd.) and “Excell” series (“Excell” is Commercially available as a registered trademark of the company) can be obtained.

The fountain solution of the present invention preferably contains at least one of the compounds represented by the general formulas (I) to (III) in an amount of 0.001 g to 3.0 g per liter of the working solution. Especially 0.02g per liter
When it is contained in a range of from 1.0 to 1.0 g, the hydrophilicity of the non-image area in the silver salt diffusion transfer printing plate is kept appropriate while at the same time the lipophilicity of the image area in the PS plate is not reduced. The effect of imparting appropriate hydrophilicity to the image area is high.
The effect of the large difference between the lipophilicity and the hydrophilicity as described above makes it possible to avoid printing problems such as background stains in which ink adheres to non-image areas during printing and ink not to be applied to image areas, and stable printing. Can be performed.

When printing a large amount of printed matter, it is common to use a PS plate having printing durability and increase the printing speed to increase the number of printed sheets per hour. If printing is performed before the dampening solution is sufficiently distributed over the entire non-image area,
Ink also adheres to the non-image area, which is likely to cause background contamination. For this reason, when performing high-speed printing, it is necessary to use dampening solution having a high spreading speed. Since the dampening solution to which the conventional IPA was added was sufficiently spread and had a high speed, such a problem did not cause much problem.
However, in recent years, IPA has been
And it is necessary to improve the spreading speed of dampening solution by some method instead of IPA addition.

The fountain solution of the present invention can be prepared without adding IPA.
2,4,7,9-tetramethyl-5-decyne-4,7-
By adding the diol or its ethylene oxide adduct, the spreading speed of the dampening solution can be improved, so that a dampening solution suitable for high-speed printing can be obtained. 2,4
Since 7,9-tetramethyl-5-decyne-4,7-diol has poor solubility, it is preferable to add it in the form of an ethylene oxide adduct from the viewpoint of solubility. This ethylene oxide adduct tends to have better solubility as the number of moles of ethylene oxide added increases. However, the effect of improving the spreading speed tends to be weaker as the number of moles of ethylene oxide added increases. Therefore, the number of moles of ethylene oxide added is 0, which is highly effective in quickly spreading the dampening solution to the entire plate.
5,2,4,7,9-tetramethyl-5-decyne-4
7-diol is most suitable for the fountain solution of the present invention.

Considering the convenience of distribution, the fountain solution is desirably supplied in the form of a stock solution which is concentrated as much as possible and diluted when used. However, in order to improve the spreading speed of the dampening solution, the number of moles of ethylene oxide added is small and the solubility is not so good.
-It is necessary to use tetramethyl-5-decyne-4,7-diol, and the enrichment cannot be increased much. It is desirable that the concentration of the undiluted solution be 20 times or more from the viewpoint of circulation, but 2,4,7,9-tetramethyl-5-
If the fountain solution containing decyne-4,7-diol or its ethylene oxide adduct is concentrated to such a ratio, two-layer separation may occur, so that it is difficult to prepare a uniform diluent at the time of use.

Therefore, the fountain solution of the present invention contains 2, 4, 7,
When adding 9-tetramethyl-5-decyne-4,7-diol or an ethylene oxide adduct thereof, a compound represented by the following general formula (IV) (formula 28) or ethylene glycol mono-tert-butyl ether is used as a solubilizing agent. It is desirable to add. General formula (IV)

Embedded image R represents an alkyl group having 1 to 4 carbon atoms, EO represents an ethylene oxide chain, and PO represents a polypropylene oxide chain. Also, m and n represent the degree of polymerization, and m / (m + n) =
0.4 to 0.7.

Among the compounds represented by the general formula (IV),
Those having a high proportion of ethylene oxide chains have a high effect as a solubilizing agent, but tend to adversely affect the resin in the image area. Conversely, those having a large proportion of polypropylene oxide chains tend to have a low effect as a solubilizing agent. Even if the proportion of ethylene oxide chains is low, those having a high molecular weight also tend to adversely affect the resin in the image area.

Therefore, as a result of various studies conducted by the present inventors,
It has been found that those having a total sum of polymerization degrees (m + n) of 20 or less can be particularly preferably used in the fountain solution of the present invention.
Of the compounds represented by the general formula (IV), specific examples of particularly preferable compounds include butanol (EO) _3.
O) ₂ adduct and ethanol (EO) _3. (PO) ₂ adduct. By adding these solubilizers, 2,4,7,9-tetramethyl-5-
It becomes possible to solubilize decyne-4,7-diol or an ethylene oxide adduct having an addition mole number of 1 to 5,
A clear fountain solution having a high concentration can be prepared. By adding these solubilizers at a ratio of 1 to 60 g per liter of a fountain solution, it is possible to prepare a stock solution concentrated to 50 times or more, which is excellent in transport and storage properties. It can be.

In addition, a hydrophilic polymer compound can be added to the fountain solution of the present invention, if necessary. Specific compounds include carboxymethylsemelose (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.

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 prevent fatty acids and the like dissolved from the ink from adhering to non-image areas and becoming oil-sensitive,
The effect of appropriately etching the plate surface is seen. Specific organic acids include citric, ascorbic, malic, tartaric, formic, propionic, succinic, glutaric, maleic, fumaric, malonic, lactic, acetic, gluconic, oxalic, and organic. And phosphonic acid. 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 wetting agent to the fountain solution of the present invention. The addition of the wetting agent makes it difficult for the water on the plate surface to dry, thereby making it possible to prevent stains on the non-image area more effectively. Specific examples of the wetting agent include ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol, triethylene glycol, polyethylene glycol, glycerin, triethanolamine, monoethanolamine, diethanolamine, glycolic acid, and pyroglutamic acid.

It is also desirable to add a chelating agent to the fountain solution of the present invention. By adding a chelating agent, calcium ions contained in the dilution water when diluting the concentrated fountain solution are concealed to suppress unnecessary precipitation and calcium carbonate from printing paper during printing. Can be suppressed, and good printing can be performed. Preferred chelating agents include, for example, ethylenediaminetetraacetic acid, diethylenetriaminepentaacetic acid, triethylenetetraminehexaacetic acid, nitrilotriacetic acid, L-glutaminediacetic acid and the like, and these may be added as salts such as alkali metal salts.

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 microorganisms and the viscosity gradually decreases, it is desirable to add a preservative or an antifungal agent. Specific compounds include salicylic acid, phenol, phenol parabutyl benzoate, sodium dehydroacetate, 4-isothiazolone-3-one, 1,2-benzisothiazolin-3-one, and the like.

It is also desirable to add a rust inhibitor to the fountain solution of the present invention. The press rollers are always affected by the fountain solution. It is desirable to use a rust inhibitor in order not to damage the printing machine even after long-term use, and specific compounds include nitrates and 1H-benzotriazole.

[0028]

Next, the present invention will be described in detail with reference to examples. With the composition shown in Table 1, each fountain solution of Samples 1 to 11 was prepared.

[Table 1]

[Printing Test] Using a sample dampening solution adjusted, a printing machine TOKO OFFSET 8000 was used.
(Tokyo Aviation Instruments Co., Ltd.) print 10,000 sheets for each test using a PS plate and a silver salt diffusion transfer plate at a printing speed of 6,000 sheets / hour, and observe and evaluate the print quality. Was done. The evaluation items are as follows. The results of each evaluation are shown in Table 2.

Stain on non-image area: The printed matter was observed, and the occurrence of stain on the non-image area was checked. 〇: No stain was observed on the printed matter even after printing 10,000 sheets. X: Stain was observed in the non-image area from the time when about 1,000 sheets were printed.

Ink application on the image area: The ink application of the printed product was observed, and the effect on the oil sensitivity of the image area of the printing plate was observed. 〇: Good ink coverage of printed matter even after printing 10,000 sheets. ×: Ink of the image area became poor after printing about 1,000 sheets.

[High-speed printing test] Under the same conditions as the printing test, only the printing speed was set to 8,000 sheets / hour and 10,000 sheets.
High-speed printing was performed at 0 sheets / hour, and the effect of each fountain solution sample on printing stability was examined. This test was performed only with a PS plate used for high-speed printing. Table 2 shows the results.
It was shown to.

Printing stability: The printed matter was observed and the effect on print quality during high-speed printing was observed. 〇: No stain was observed on the printed matter even after high-speed printing at 10,000 sheets / hour. Δ: At high-speed printing of 8,000 sheets / hour, stains were observed in the non-image area from the 5,000th sheet.

[Concentration test] With respect to each fountain solution composition, a stock solution was prepared by changing the concentration ratio, and it was checked to what extent each stock solution could be concentrated.

Concentration property: Two layers were not separated. 〇: 50 times or more concentration possible △: Less than 50 times, 20 times or more concentration possible ×: 20 times concentration stock solution preparation is not possible

[0036]

[Table 2]

As shown in Table 2, the general formulas (I) to (II)
When printing was performed using the fountain solution of the present invention (Sample Nos. 1 to 6) containing any of the compounds represented by I), a silver salt diffusion transfer plate and a PS plate were used as plate materials. Whichever was used, a printed matter having good print quality could be produced without using IPA. On the other hand, Sample No. 1 which is a general fountain solution for PS plate was used. 7 and No. 7 9
In the case where a dampening solution (sample No. 8) for a silver salt diffusion transfer plate containing colloidal silica was used, there was a problem in print quality when another plate was used.

Further, 2,4,7,9-tetramethyl-5-
Sample No. containing an ethylene oxide adduct of decyne-4,7-diol. Sample No. 1 containing no fountain solution was used. It can be seen that the printing stability in high-speed printing is superior to that of No. 4.

Also, 2,4,7,9-tetramethyl-5-
In a fountain solution containing an ethylene oxide adduct of decyne-4,7-diol, sample No. 1 also contained a solubilizing agent such as a butanol EO / PO adduct or ethylene glycol mono-tert-butyl ether. 1 and sample no. Sample No. 6 does not contain any solubilizer. It can be seen that the concentration property is superior to that of No. 5. On the other hand, the sample No. of the comparative example. 11 is
It can be seen that, although it is excellent in compatibility with various plate materials, it is very inferior in terms of concentrating properties despite containing a solubilizing agent.

[0040]

As described above, the fountain solution according to claim 1 of the present invention has excellent compatibility with both PS plates of silver salt diffusion transfer plates, and printing in which various plate materials are mixed. Even under the conditions, high-quality printing can be performed with the same dampening solution without replacing the dampening solution. At the same time, it is possible to maintain proper print quality without using IPA that places a large burden on the work environment.

According to the second aspect, in addition to the effect of the first aspect, since the spreading speed of the dampening solution can be improved without using IPA, a dampening solution suitable for high-speed printing can be obtained. Can be

Furthermore, according to the third and fourth aspects, even if the concentration is increased to 20 times or more, it is easy to prepare a uniform diluent at the time of use without causing separation of two layers. In addition, it is capable of solubilizing 2,4,7,9-tetramethyl-5-decyne-4,7-diol having low solubility and ethylene oxide adduct having an addition mole number of 1 to 5, and has a high concentration and a clear fountain solution. An undiluted solution can be prepared, and a product with excellent transport and storage properties can be obtained. In addition, convenience of distribution can be secured.

Claims (4)

[Claims] 1. A compound represented by the following general formula (I):
A fountain solution composition for lithographic printing, comprising at least one compound selected from the compounds represented by the formulas (III) and (III). General formula (I) a, b, d, and e represent an alkylene chain having 1 to 10 carbon atoms, and these a, b, d, and e may be substituted with a hydroxyl group, and include an ether bond or polyethylene oxide having a polymerization degree of 5 to 20. You may go out. A, b, d, e
May be the same or different. X and Y represent any of a hydrogen atom, a hydroxyl group, a carboxyalkyl group, a sulfoalkyl group, and a hydroxyalkyl group, and X and Y may be the same or different. General formula (II) General formula (III) n = an integer of 5 to 10000 In the general formulas (II) and (III), R ₁ , R ₂ , R ₃
May be the same or different, and represent a hydrogen atom or the following formula (Formula 4). F represents an alkylene group having 2 to 10 carbon atoms, and these alkylene groups may be substituted with a hydroxyl group, and may have an ether bond or a polymerization degree of 5 to 30.
May contain a polyethylene oxide group. g,
h and i represent a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, which may be the same or different. Embedded image 2. The fountain solution composition for lithographic printing according to claim 1, further comprising 2,4,7,9-tetramethyl-5-decyne-4,7-diol or an ethylene oxide adduct thereof. 3. The fountain solution composition for lithographic printing according to claim 2, comprising a compound represented by the following general formula (IV) (Formula 5). General formula (IV) R represents an alkyl group having 1 to 4 carbon atoms, EO represents an ethylene oxide chain, and PO represents a polypropylene oxide chain. Also, m and n represent the degree of polymerization, and m / (m + n) =
0.4 to 0.7. 4. The fountain solution composition for lithographic printing according to claim 2, further comprising ethylene glycol mono-tert-butyl ether.