JP2929645B2 - Printing ink - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to a printing ink containing a drying inhibitor and a specific high-boiling organic solvent, and more particularly to the printing ink surface in a container or printing when printing is interrupted. By suppressing or delaying the drying of the printing ink attached to each part of the printing machine, it is easy to refill the printing machine with ink from the can, and it is possible to start printing smoothly from the interruption of printing. Related.

(Prior art) Conventionally, various antioxidants have been added as drying inhibitors to printing inks for the purpose of suppressing or delaying the drying of oxidation-polymerized lithographic inks, or these antioxidants have been added to appropriate solvents. It has been practiced to mix dissolved solutions in printing inks as drying inhibitors. Examples of the drying inhibitor include hydroquinone, t-butylhydroquinone, 2,6
-Di-t-butyl-p-cresol, p-nonylphenol, ascorbic acid and the like are used. Among these drying inhibitors, hydroquinones, in particular, have a large drying inhibiting effect and are often used in a mixture with printing inks. In addition, when printing is interrupted, various antioxidants are dissolved in an appropriate solvent to suppress drying of the printing ink adhering to the surface of the printing press, and a printing solution adhering to the surface of the printing press as a solution. It is common practice to suppress the drying of the printing ink by spraying the ink.

For example, JP-A-62-45677 describes a surface drying inhibitor for a printing ink comprising a polymerization inhibitor or a polymerization retarder, and JP-A-1-132267 discloses that hydroquinone is a glycol monoether. It is described that the surface drying of the printing ink can be prevented by mixing a drying inhibitor dissolved in the printing ink with the printing ink.

(Problems to be Solved by the Invention) When a drying inhibitor is mixed with a printing ink in a powder form, the drying inhibitor is present in the printing ink in the form of solid particles without being dissolved. When the use amount of the drying inhibitor increases,
The drying inhibitor in the printing ink causes transfer failure during printing, accumulates on the rollers of the printing press, on the plate surface or on the blanket surface, and causes a problem of piling. In extreme cases, the subsequent printing is impossible. There was a point.

For this reason, a drying inhibitor has been prepared by dissolving a drying inhibitor in alcohols or glycol monoethers to solve the above problems.

However, when a low-boiling organic solvent having a boiling point of less than 150 ° C. is used, the organic solvent tends to evaporate during printing or storage, so that a drying inhibitor precipitates in the printing ink,
As a result, the same phenomenon as in the case of mixing the powder as it is often occurs. Further, even with a high boiling point organic solvent having a boiling point of 150 ° C. or higher, due to the difference in affinity with the vehicle / pigment in the printing ink, the fluidity of the printing ink is lacking,
In terms of safety and working environment during production and use, there has been a demand for the use of an organic solvent having a higher boiling point and a higher flash point and a lower vapor pressure than at present. Also, since alcohols and glycol monoethers strongly affect the water emulsification phenomenon of printing ink, if a large amount of a conventional dissolution-type drying inhibitor is added, the printing ink will not adhere to the ink roller, or the roller will peel off. However, there is a problem that the trouble occurs.

(Means for Solving the Problems) The present inventors have conducted intensive studies in order to meet the above-mentioned problems, and as a result, compared with glycol monoethers of a high boiling point solvent used as a drying suppressant, By adding a compound represented by the following general formula (I) having the above solubility, a high boiling point and a high flash point, and a low vapor pressure to a printing ink, the drying inhibitor can be dissolved in the printing ink. With the aid, and by adding it separately from the drying inhibitor, the desired printing ink was successfully obtained without adding an unnecessary organic solvent to the printing ink.

That is, in order to solve the above-mentioned problems, the present invention provides a drying inhibitor and a compound represented by the following general formula (I): R ¹ -(-OR ² ) _n -O-CO-R ³ (I) ¹ is a hydrogen atom, an alkyl group having 1 to 6 carbon atoms or a phenyl group, R ² is -C ₂ H ₄ -or -C ₃ H _6- , n is an integer of 1 to ³ , R ³ is hydrogen A printing ink characterized by containing a solvent represented by the following formula:

Examples of the drying inhibitor used in the present invention include hydroquinone, t-butylhydroquinone, 2,6-di-t
-Butyl-p-cresol, p-nonylphenol, and ascorbic acid.

The amount of the drying inhibitor used in the printing ink of the present invention is 0.01%.
The range is preferably from 5 to 5% by weight, and particularly preferably from 0.1 to 1% by weight.

The solvent represented by the general formula (I) used in the present invention preferably has a boiling point of 150 ° C. or higher, particularly preferably 190 ° C. or higher. Examples of such a solvent include ethylene glycol acetate, ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, ethylene glycol monopropyl ether acetate, ethylene glycol monobutyl ether acetate, ethylene glycol monoisopropyl ether acetate, and ethylene glycol monoisobutyl. Ether acetate, ethylene glycol monohexyl ether acetate, ethylene glycol monophenyl ether acetate, diethylene glycol acetate, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, diethylene glycol monopropyl ether acetate, diethylene glycol Nobutyl ether acetate, diethylene glycol monoisopropyl ether acetate, diethylene glycol monoisobutyl ether acetate, diethylene glycol monohexyl ether acetate, diethylene glycol monophenyl ether acetate, triethylene glycol acetate, triethylene glycol monomethyl ether acetate, triethylene glycol monoethyl ether acetate, triethylene Glycol monopropyl ether acetate, triethylene glycol monobutyl ether acetate, triethylene glycol monoisopropyl ether acetate, triethylene glycol monoisobutyl ether acetate, triethylene glycol monohexyl ether acetate, triethyl Glycol monophenyl ether acetate,
Propylene glycol acetate, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, propylene glycol monopropyl ether acetate, propylene glycol monobutyl ether acetate, propylene glycol monoisopropyl ether acetate, propylene glycol monoisobutyl ether acetate, propylene glycol monohexyl ether acetate , Propylene glycol monophenyl ether acetate, dipropylene glycol acetate, dipropylene glycol monomethyl ether acetate, dipropylene glycol monoethyl ether acetate, dipropylene glycol monopropyl ether acetate, dipropylene glycol mono Chill ether acetate, dipropylene glycol monoisopropyl ether acetate,
Dipropylene glycol monoisobutyl ether acetate, dipropylene glycol monohexyl ether acetate, dipropylene glycol monophenyl ether acetate, tripropylene glycol acetate,
Tripropylene glycol monomethyl ether acetate, tripropylene glycol monoethyl ether acetate, tripropylene glycol monopropyl ether acetate, tripropylene glycol monobutyl ether acetate, tripropylene glycol monoisopropyl ether acetate, tripropylene glycol monoisobutyl ether acetate, tripropylene glycol mono Organic solvents such as hexyl ether acetate and tripropylene glycol monophenyl ether acetate.

Among these organic solvents, there is little dissolution and expansion of the image area of the PS plate used for lithographic printing, and even when added to printing ink, there is no significant change in the emulsification amount of water, and Those which do not deteriorate the roughness of the ink are particularly preferable. Examples of these organic solvents include ethylene glycol monobutyl ether acetate, diethylene glycol monoethyl ether acetate, and the like.

The amount of the organic solvent represented by the general formula (I) in the printing ink of the present invention is preferably in the range of 0.05 to 25% by weight,
A range of 0.5 to 5% by weight is particularly preferred.

The ink component of the present invention may be the same as a conventional oxidative polymerization type printing ink except that the drying inhibitor and the organic solvent represented by the general formula (I) are added. Conventional oxidative polymerization type printing inks include, for example, pigments 10 to 30% by weight, synthetic resins 20 to 35% by weight, drying oils 15 to 30% by weight, petroleum solvents
A mixture comprising 10 to 25% by weight and 0.3 to 5% by weight of an auxiliary agent such as a dryer is mixed and kneaded by a conventionally known technique.

Examples of petroleum organic solvents that are commonly used in printing inks together with the organic solvent represented by the general formula (I) include, for example, spindle oil, No. 3, No. 4, No. 5, No. 6, No. 7 solvent (Nippon Oil And the like).

The printing ink of the present invention may be produced by separately mixing the organic solvent represented by the general formula (I) and the drying inhibitor with the above-mentioned conventional oxidative polymerization type printing ink. It can also be produced by mixing a solution obtained by dissolving a drying inhibitor in an organic solvent represented by the general formula (I) in an oxidative polymerization type printing ink.

(Examples) Hereinafter, the present invention will be described in more detail with reference to examples. In addition, "part" in an example represents "part by weight".

Examples 1 to 4 Oxidation polymerization type lithographic printing ink "Space Color Graph-G" (manufactured by Dainippon Ink and Chemicals, Inc.) was added with a drying inhibitor and an organic solvent described in Table 1 and a three-roll mill was used. The mixture was thoroughly mixed and kneaded to obtain a printing ink.

Comparative Examples 1 to 4 Oxidation polymerization type lithographic printing ink "Space Color Graph-G" was added with a drying inhibitor and an organic solvent described in Table 2 and thoroughly mixed and kneaded using a three-roll mill. I got

In Tables 1 and 2, the drying inhibitor A was hydroquinone, the drying inhibitor B was 2,6-di-t-butyl-p-cresol, and the soluble drying inhibitor was diethylene glycol monohexyl ether 6 of hydroquino. % Solution, alcohol solvent is isopropyl alcohol, glycol ether ester solvent A is diethylene glycol monoethyl ether acetate, and glycol ether ester solvent B is ethylene glycol monobutyl ether acetate.

Using the printing inks obtained in Examples 1 to 4 and Comparative Examples 1 to 4, the presence / absence of precipitation of the drying inhibitor, the drying performance of the air and the printing test were evaluated. The results are shown in Tables 1 and 2. It was shown to.

In addition, the drying method of an ink and the evaluation method and evaluation criteria of a printing test are as follows.

[Dryability of Ink] (1) Printing was performed on each surface of sulfuric acid paper using each printing ink, and the drying time was measured.

Less than 6 hours ○ 6 to 10 hours △ 10 hours or more × (2) Printing was performed on a glass plate using each printing ink, and the drying time was measured.

48 hours or more: 24 hours to 48 hours: less than 24 hours: × [Printing test] Each printing ink, 4-color printing machine with CC1 “RVK-3B” (man Roland), “Dick etch” 8000 sheets / hour on coated paper using "Liquid NA-100" (fountain solution manufactured by Dainippon Ink and Chemicals, Inc.), "R-70" (blanket manufactured by Dunlop) and plate material manufactured by Polychrome. Printing was performed at a speed, and the printing adequacy was evaluated when the printing was restarted 12 hours after the stop of the piling, roller baldness, and printing.

Good ……… Somewhat bad …… △ Unusable …… × Not measured ……… − (Effect of the Invention) The printing ink of the present invention does not suppress or delay the drying of the ink on an absorbent printing material such as paper, and the printing ink surface in a storage container or a printing machine when printing is interrupted. It is characterized in that the drying of the printing ink attached to the surface of each part is delayed.

In addition, compared to conventional printing inks containing a solution-type drying inhibitor, the solvent used has a higher boiling point and a higher flash point, and has a lower vapor pressure. Can be improved.

Further, in the printing ink of the present invention, since the drying inhibitor is present in a state of being dissolved in the ink, troubles such as piling are prevented, and the effect is obtained by adding a small amount of an organic solvent. Can also be solved.

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int. Cl. ⁶ , DB name) C09D 11/00-11/20

Claims (1)

(57) [Claims] (1) a drying inhibitor and a compound represented by the general formula (I): R ¹ -(-O-R ² ) _n -O-CO-R ³ wherein R ¹ is a hydrogen atom, an alkyl having 1 to 6 carbon atoms. A group or a phenyl group, R ² represents —C ₂ H ₄ — or —C ₃ H ₆ —, n represents an integer of 1 to 3, and R ³ represents a hydrogen atom, a methyl group or an ethyl group.) Lithographic printing ink comprising a solvent to be used.