JPH06127170A - Damping water concentrate for printing - Google Patents

Abstract

PURPOSE:To prevent decomposition and to enhance various printing aptitudes by preparing a damping water concentrate for printing having specific pH by adding a specific compd. and other water compatible antifungal agent to water and diluting the same with water to prepare alkaline damping water for printing. CONSTITUTION:Planographic printing is performed using a printing plate wherein the part corresponding to an image line part is set to a sensitized surface and the part corresponding to a non-image line part is set to a hydrophilic surface. That is, ink is bonded to the sensitized surface and damping water is bonded to the hydrophilic surface to perform printing by the mutual repulsive action of ink and damping water. In this case, a damping water concentrate for printing with pH10-13.5 is prepared by adding a 1,2-benzisothiazolin-3-one compd. and other water-compatible antifungal agent to water. Alkaline damping water is prepared by diluting the damping water concentrate with water. By this method, a damping water compsn. generating no decomposition in spite of long-term preservation or use and capable of realizing stable planographic printing is obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fountain solution concentrate for lithographic printing, and more particularly to a fountain solution concentrate diluted with water to be used as a fountain solution for printing.

[0002]

2. Description of the Related Art Lithographic printing is a printing method in which printing is performed by using a printing plate in which a portion corresponding to an image area is an oil-sensitive surface and a portion corresponding to a non-image area is a hydrophilic surface. That is, the ink is attached to the oil-sensitive surface and the dampening water is attached to the hydrophilic surface, and the mutual repulsion between the ink and the dampening water is used for printing. The fountain solution is applied to the plate surface before the ink is attached to the plate surface. The functions of dampening water are (1) preventing ink from adhering to non-image areas, (2) cleaning the plate surface, (3) preventing changes in the image area, and (4) keeping the plate temperature constant. . Since dampening water has the above-mentioned functions, various compounds are added to water. The pH of the dampening water is acidic in the ordinary PS plate offset printing method, but alkaline in the newspaper offset press. The reason why the fountain solution is made alkaline is that paper powder easily mixes with the fountain solution in the printing method in which the printing ink is set by penetrating the paper like newspaper printing, and aluminum sulfate contained in the paper is used as a sizing agent. This is because it is acidic in water and needs to be neutralized.

Since dampening water is mainly composed of water, it may rot or mold during use or storage. In particular, in a printing environment, the paper dust is dampened and mixed into the water, so that the dampening water is easily decomposed. When the dampening water rots, it not only gives off a bad odor, but also slime is generated and adheres to the dampening water tank, the piping of the printing machine and the water boat, and in some cases, it adheres to the plate surface and the roll via the water supply roll and becomes dirty. turn into. Further, the dampening water is discolored, polluted, and the pH is changed, and the physical properties of the dampening water are also changed. In newspaper printing, there is a case where dampening water is supplied by a spray nozzle method, and the occurrence of slime causes a serious accident in which nozzles are clogged and dampening water is not supplied and stains occur. Every time, the printing worker must clean or re-prepar the dampening water, which is an obstacle to the work. The decay and mold that occur in the fountain solution are caused by the growth of various fungi that originally exist in the water.

Conventionally, preservatives and fungicides have been added to dampening water to prevent spoilage, for example,
Japanese Patent Application Laid-Open No. 57-125096 discloses a fountain solution containing a 4-isothiazolin-3-one compound.
In addition, in JP-A-4-161387, as a preservative added to dampening water, in addition to the above compounds, phenol or a derivative thereof, formalin, an imidazole derivative, sodium dehydroacetate, a benzotriazole derivative, an amisinganidine derivative, a quaternary compound. Ammonium salts, pyridine,
Derivatives such as quinoline and guanidine, diazines, triazole derivatives, oxazoles and oxazine derivatives are disclosed. However, the above preservatives are effective in acidic fountain solution but not in alkaline fountain solution. For example, 4-isothiazolin-3-one has a problem that its antiseptic action is not exhibited due to its poor solubility in alkaline.

[0005]

DISCLOSURE OF THE INVENTION The present invention provides a fountain solution composition for lithographic printing, which does not rot even after long-term storage or use and is capable of realizing stable lithographic printing and having excellent printing suitability. To do.

[0006]

The invention according to claim 1 of the present application is characterized by containing a 1,2-benzisothiazolin-3-one compound and a water-miscible fungicide other than the above, PH 10 to PH 13. No. 5 relates to a dampening water concentrate for printing, and the invention of claim 2 relates to a dampening water concentrate for alkaline printing obtained by diluting the above dampening water concentrate with water.

1,2-benzisothiazoline of the present invention
The 3-one compound mainly acts as a preservative and is a compound represented by the following general formula.

[0008]

[Chemical 1]

(In the formula, R represents a hydrogen atom or a lower alkali group, X represents a hydrogen atom, an alkyl group, an alkoxy group, a halogen atom, etc., and n is an integer of 0 or 4.) Of the 2-benzisothiazolin-3-one compounds, 1,2-benzisothiazolin-3-one having the following structural formula is preferably used.

[0010]

[Chemical 2]

The 1,2-benzisothiazolin-3-one compound is contained in the fountain solution concentrate of the present invention in an amount of 0.1 to 20% by weight,
Preferably 0.5 to 10% by weight is contained.

The water-miscible fungicide of the present invention compensates for the inferior mold performance when the 1,2-benzisothiazolin-3-one compound is used alone. Water-miscible fungicides are those which are water-soluble or dispersed in water in the form of fine particles, for example, "Coatside" containing a trade name benzimidazole compound marketed by Takeda Pharmaceutical Co., Ltd. as an active ingredient. , "Courtside 55D", "Courtside D", "Courtside DX", "Courtside S"
P "," Coatside SP-68 "," Slaoff 95 "containing an organic nitrogen-sulfur compound as an active ingredient," Coatside H "containing an organic iodine compound as an active ingredient, and the like. The water-miscible fungicide is contained in the fountain solution concentrate in an amount of 0.1 to 10% by weight, preferably 0.5 to 3% by weight.

The fountain solution concentrate of the present invention has a pH of 10 to 1
Alkaline of 3.5. Examples of the compound to be added to the fountain solution to make it alkaline include water-soluble alkali metal silicates and water-soluble alkali metal metaphosphates. The water-soluble alkali metal silicate has a function of keeping the dampening water alkaline and facilitating uniform adhesion of the dampening water to the image area. As the water-soluble alkali metal silicate,
So-called water glass can be used, and examples of such a compound include sodium metasilicate (Na ₂
SiO ₃ ), sodium orthosilicate (Na ₄ Si
O _4), sodium disilicate _{(Na 2 Si 2 O 5)} , sodium tetraborate silicate (Na ₂ Si ₄ O _9), and there is a corresponding potassium salt.

The content of the water-soluble alkali metal silicate is
It is 0.1 to 10% by weight, preferably 0.5 to 5% by weight. The water-soluble alkali metal metaphosphate is (HP
It is an alkali metal salt of O ₃ ) _n , and sodium trimetaphosphate, sodium tetrametaphosphate, sodium polymetaphosphate and the corresponding potassium salt can be used. The water-soluble alkali metal metaphosphate has a function of being mixed in dampening water when used to capture metal ion impurities such as calcium ions. That is, the calcium ions contained in the paper are mixed in the dampening water and react with the water-soluble alkali metal silicate salt to become a water-insoluble calcium silicate salt, which reduces the function of the dampening water. Prevent. The content of the water-soluble alkali metal metaphosphate is 0.5 to 20% by weight, preferably 1 to 5% by weight.

In addition to the above compounds, alkali metal phosphates such as trisodium phosphate and tripotassium phosphate, surfactants, defoamers and the like can be added to the fountain solution concentrate of the present invention. As the surfactant, dialkyl sulfosuccinate, alkyl sulfate ester salt, hydroxyalkane sulfonic acid, alkane sulfonic acid, dialkyl sulfosuccinic acid, linear alkylbenzene sulfonate, alkylnaphthalene sulfonic acid, polyoxyethylene alkyl sulfophenyl ethyl ester salt And the like, and nonionic surfactants such as polyoxyethylene alkylphenol, polyoxyethylene alkylphenyl ether, polyoxyethylene styryl phenyl ether, and polyoxyethylene polyoxypropylene alkyl ether. As the defoaming agent, a silicone-based emulsion type or solution type can be used. The fountain solution concentrate of the present invention can be diluted 100 to 300 times with water and used as fountain solution having a pH of 9 to 11.

[0016]

[Examples] 97 parts by weight of tap water, 2 parts by weight of water-soluble sodium silicate, 1 part by weight of sodium phosphate, 0.05 part by weight of nonionic water-soluble surfactant, 0.02 part by weight of silicone antifoaming agent A stock solution of fountain solution (pH 13) is prepared. According to the formulation shown below, 1,2-benzisothiazoline-3-
A fountain solution concentrate containing an on compound and a water miscible fungicide is prepared. As the 1,2-benzisothiazolin-3-one compound, a commercially available product containing 10% of the active ingredient was used. As the water-soluble antifungal agent, a commercially available product of Takeda Pharmaceutical Co., Ltd. was used.

Comparative Example 1 Dampening water stock solution 95 parts by weight 1,2-benzisotizolin-3-one compound commercial product 5 parts by weight Example 1 Dampening water stock solution 94 parts by weight 1,2-benzisotizolin-3-one Commercially available on-compound 5 parts by weight Organic nitrogen-sulfur compound Antifungal agent Trade name "Slaoff 95" 1 part by weight Example 2 Stock solution of dampening solution 94 parts by weight Commercially available 1,2-benzisotizolin-3-one compound 5 parts by weight Part Organic iodine compound Antifungal agent Trade name "Coatside H" 1 part by weight Example 3 Damping water stock solution 94 parts by weight 1,2-benzisothizolin-3-one compound commercial product 5 parts by weight Benzimidazole compound Mold agent Product name “Coatside D” 1 part by weight In addition, as a comparative example, a fountain solution stock solution (pH 13) containing no 1,2-benzisothiazolin-3-one compound and a water-soluble fungicide is used. To. Comparative Example 2 Dampening water stock solution 100 parts by weight

0.5 parts by weight of the fountain solution concentrates of the above Examples and Comparative Examples were diluted with 99.5 parts by weight of tap water to obtain the fountain solution used in the following experiments. Experiment 1. Microbial inhibition test Add 5 parts by weight of seed suspension (shown below from a spoiled dampening tank) to 100 parts by weight of fountain solution of each composition, mix and incubate at 27 ° C for 30 days to suppress the effects of microorganisms. Make a decision. The viable cell counts measured by the hygiene test method were as follows. Bacteria 1.0 × 10 ⁶ (pieces / milliliter) Mold 1.0 × 10 ² (pieces / milliliter) The criteria for the test are as follows: Bacteria 1. Occurrence of bacteria Viable count 1.0 x 10 ⁶ cells / ml or more 2. Occurrence of bacteria 1.0 × 10 ^{5 to} 1.0 × 10 ⁶ cells / ml 3. Occurrence of bacteria 1.0 × 10 ^{3 to} 1.0 × 10 ⁵ cells / ml 4. Occurrence of bacteria is slight 1.0 × 10 ^{2 to} 1.0 × 10 ³ cells / ml 5. No generation of bacteria 1.0 × 10 ² / ml or less Mold 1. Occurrence of bacteria Viable count 1.0 × 10 ³ / ml or more 2. Occurrence of bacteria 1.0 × 10 ^{2 to} 1.0 × 10 ³ cells / ml 3. Occurrence of bacteria 1.0 × 10 ^{1 to} 1.0 × 10 ² cells / ml 4. Occurrence of bacteria is slight 1.0 x 10 ¹ cells / ml or less 5. Table 1 shows the results of the undetected test in which no bacterium was generated.

[0019]

[Table 1]

Experiment 2. Printing test and microbial inhibition result in actual machine Diluting with 0.5 parts by weight of the fountain solution concentrates of the examples and comparative examples and 99.5 parts by weight of tap water, and performing a printing test under the following conditions as dampening water The results after 1 month of use are shown in Table 2. Printing machine: Tokyo Kikai Seisakusho Co., Ltd. keyless off wheel press T-1000 type Printing ink: News King KL ink GT (manufactured by Toyo Ink Mfg. Co., Ltd.) Printing speed: 120,000 copies / hour Paper: Newspaper dampening mechanism: RYCO GRAPHIC spray nozzle system Dampening water tank: RYCO GRAPHIC tank Water temperature 25 ° C to 29 ° C Temperature and humidity: 26 ° C to 31 ° C 60 to 80% RH Number of printed copies: 4.5 million copies

[0021]

[Table 2]

[0022]

The fountain solution of the present invention has a high antiseptic effect and is free from spoilage of the fountain solution due to the growth of various bacteria, molds, bacteria and microorganisms even after long-term use. Therefore, by using the composition for fountain solution of the present invention as fountain solution, printing trouble due to decay of fountain solution is eliminated, and the fountain solution tank,
This makes it easier to clean the piping and the water jet of the printing machine, and improves the work efficiency of those who engage in offset printing. Therefore, the improvement of the printing work environment and the reduction of the dampening water cost can be achieved.

Claims (2)

[Claims] 1. A fountain solution concentrate for printing having a pH of 10 to 13.5, which contains a 1,2-benzisothiazolin-3-one compound and a water-miscible fungicide other than the above. 2. A fountain solution for alkaline printing, which is obtained by diluting the fountain solution concentrate of claim 1 with water.