JPH01132671A - printing ink - Google Patents

Abstract

PURPOSE:To obtain a printing ink free of a piling trouble and having excellent drying-inhibiting property, by adding a drying inhibitor for a printing ink obtained by dissolving hydroquinone in a high-boiling organic solvent. CONSTITUTION:A drying inhibitor for a printing ink is obtained by dissolving 5-35wt.% hydroquinone in a hydroquinone-dissolving high-boiling organic solvent of a b.p. >=150 deg.C, such as an organic solvent of the formula (wherein R1 is H or 1-6C alkyl or a phenyl, R2 is C2H4 or C3H6, and n is 2 or 3), e.g., dipropylene glycol monopropyl ether and, optionally, another high-boiling organic solvent (e.g., spindle oil). 0.01-5wt.% this drying inhibitor is added to, for example, a printing ink such as an oxidationpolymerizable offset ink A and mixed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the invention] (Industrial field of application) The present invention relates to a printing ink containing a drying inhibitor for printing ink, and more particularly, the present invention relates to a printing ink containing a drying inhibitor for printing ink, and more particularly, the present invention relates to a printing ink containing a drying inhibitor for printing ink. Uses a drying inhibitor for printing ink that is effective in suppressing or delaying the drying of printing ink adhering to the surface of the printing ink in the container or on the surface of various parts of the printing machine when printing is interrupted, without delaying the drying of the printing ink. Regarding printing ink.

(Prior art) Conventionally, various antioxidants, anti-aging agents, deterioration inhibitors, polymerization inhibitors, polymerization retardants, etc. have been used for the purpose of suppressing and delaying the drying of oxidative polymerization type printing inks such as lithographic inks and letterpress inks. Agent 1 Polymerization inhibitor etc. as a drying inhibitor.

It has been added to printing inks. In particular, hydroquinone is often added to printing inks because of its great drying inhibiting effect. In addition, when printing is interrupted, various antioxidants, anti-aging agents, deterioration inhibitors 2 polymerization inhibitors 1
Polymerization retarder 2 It is common practice to dissolve a polymerization inhibitor or the like in a suitable solvent and spray the solution as a solution onto printing ink adhering to the surface of various parts of a printing machine to suppress drying.

For example, in Japanese Patent Application Laid-Open No. 61-211380.

The addition of radical-scavenging organic compounds to printing inks has been described. This radical scavenging compound is a compound having an active group containing a sulfur atom.

Phenol compounds and amine compounds are disclosed.

Further, Japanese Patent Application Laid-Open No. 62-45677 describes a surface drying inhibitor for printing ink which is composed of a double polymerization inhibitor or a polymerization retarder.

(Problems to be solved by the invention) Hydroquinone has very low solubility in petroleum solvents commonly used in printing inks, and conventionally when added to printing inks it has been added in the form of powder. Even in printing ink, hydroquinone exists in the form of solid particles without being dissolved. Therefore.

When the amount added is large, only the solid particles of hydroquinone in the printing ink cause poor transfer during printing.

It accumulates on the second plate on the roller of the printing press or on the blanket, causing a problem called piling, and in extreme cases may even make printing and m'krt impossible, so the amount of addition is naturally limited. Furthermore, when hydroquinone is added to printing ink in the form of powder, the solid particles of hydroquinone (re)agglomerate during storage of the printing ink, resulting in larger hydroquinone particles, which often promotes the aforementioned piling problem.

Additionally, since hydroquinone has traditionally been added to printing inks in powder form, it naturally exists in the ink film printed on paper or other printing materials in the same powder state as when the ink is stored. There was also a drawback that drying of the ink on the printing material was delayed and suppressed.

It is also known that polyhydric phenols other than hydroquinone are used as drying inhibitors, but polyhydric phenols other than hydroquinone do not have a sufficient drying inhibiting effect, so some degree of effect can be expected. must be added in a considerable amount, and adding too much tends to affect the drying on the printed matter.

Furthermore, as described in the examples of JP-A No. 62-45677, when a low-boiling organic solvent with a boiling point of less than 150° C. is added, the organic solvent evaporates.

The result is that hydroquinone is present in powder form, often giving the same result as adding powder.

There has been little known of a method for dissolving hydroquinone at a concentration sufficient to provide a sufficient drying-inhibiting effect and also providing a drying-inhibiting effect over a long period of time.

[Structure of the invention]

(Means for Solving the Problems) The present invention is a printing ink containing a drying inhibitor for printing ink prepared by dissolving hydroquinone in one or more high-boiling organic solvents; The present invention relates to a printing ink in which the high boiling point organic medium is a compound represented by the following general formula [I].

R++0-Rz) ,, -OH(1) (However, R1 in the above formula represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or a phenyl group, and RZ is CzHa-
or -CiHi-, and n represents an integer of 2 to 3. ) Furthermore, the present invention relates to a printing ink in which the above-mentioned high-boiling point organic medium is added with a printing ink drying inhibitor consisting of a compound represented by the above-mentioned general formula [I] and a high-boiling point organic solvent commonly used in printing inks. .

As a result of extensive research, the present inventors have found that by selecting a high boiling point organic solvent as a solvent for dissolving nohydroquinone, and by using the compound of general formula (1) above, a drying inhibitor for printing ink can be obtained. It was discovered that a solution of hydroquinone could be obtained at a concentration sufficient to be effective as a
This led to the present invention.

The high boiling point organic solvent according to the present invention has a boiling point of 150°C.
As mentioned above, the organic solvent preferably has a boiling point of 180° C. or higher and dissolves hydroquinone.

Examples, j Ha, ethylene glycol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, ethylene glycol monoisopropyl ether, ethylene glycol monoisobutyl ether, ethylene glycol monohexyl ether, ethylene Glycol monophenyl ether, diethylene glycol.

Diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monopropyl ether, diethylene glycol monoisopropyl ether, diethylene glycol monobutyl ether, diethylene glycol monoisoptyl ether, diethylene glycol monohexyl ether, diethylene glycol monophenyl ether, triethylene glycol, triethylene glycol Monomethyl ether, triethylene glycol monoethyl ether, triethylene glycol monopropyl ether, triethylene glycol monoisopropyl ether, triethylene glycol monobutyl ether, triethylene glycol monoisobutyl ether, triethylene glycol monohexyl ether, triethylene glycol mono Phenyl ether, propylene glycol, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol monoisopropyl ether, propylene glycol motubutyl ether, propylene glycol monoisobutyl ether, propylene glycol monobutyl ether, propylene glycol monoisobutyl Ether, propylene glycol monohexyl ether, propylene glycol monophenyl ether, dipropylene glycol, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol monopropyl ether, dipropylene glycol monoisopropyl ether, dipropylene glycol mono Butyl ether, dipropylene glycol monoisobutyl ether, dipropylene glycol monobutyl ether, dipropylene glycol monoisobutyl ether, dipropylene glycol monohexyl ether, dipropylene glycol monophenyl ether, tripropylene glycol, tripropylene glycol monomethyl ether, tripropylene glycol mono Organic solvents such as ethyl ether, tripropylene glycol monopropyl ether, tripropylene glycol monoisopropyl ether, tripropylene glycol monobutyl ether, tripropylene glycol monoisobutyl ether, tripropylene glycol monohexyl ether, tripropylene glycol monophenyl ether, etc. .

Furthermore, dimethyl adipate, di-2-ethylhexyl adipate, diisobutyl adipate, dibutyl adipate, diisodecyl adipate, dibutyl glycol adipate, di-2-ethylhexyl azelate dibutyl sebacate, di-2-ethylhexyl sebacate, methyl acetyl lysyllate.

Diethyl maleate, dibutyl maleate, di-2-ethylhexyl maleate, dibutyl fumarate.

Di-2-ethylhexyl fumarate, trimethyl phosphate, triethyl phosphate, tributyl phosphate,
Ester organic solvents such as tri-2-ethylhexyl phosphate and tributoxyethyl phosphate can also be used.

According to detailed research by the present inventors, the amount of hydroquinone in the drying inhibitor is generally 5 to 35% by weight, more preferably 15 to 35% by weight, and within this range. The object of the present invention can be fully achieved. Regarding printing ink, the purpose of the present invention can be sufficiently achieved by containing the above-mentioned drying inhibitor in the printing ink, generally 0.01 to 5% by weight, more preferably 0.1 to 3% by weight. I can do it.

The components of the printing ink of the present invention may be the same as in the prior art in each case, except for the addition of the drying inhibitor of the present invention. Furthermore, if necessary, an additive having a drying suppressing effect can be used in combination with hydroquinone.

Regarding the solvent of dry raccoon suppressant, it hardly dissolves the image area of the 28 plate used for lithographic printing, and when added to printing ink, it hardly reduces the amount of emulsification of printing ink, and it can be stored for a long time. In this case, it is preferable to use an ink that does not deteriorate the feel of the printing ink.9 For example, dipropylene glycol monobutyl ether.

Use dipropylene glycol monopropyl ether, etc.

Also, as a solvent for the drying inhibitor, petroleum-based organic solvents 9, such as spindle oil, No. 3, which are commonly used in printing inks, as well as the high-boiling organic solvents described above.

Solvent No. 4, No. 5, No. 7 solvent (manufactured by Nippon Oil Co., Ltd.), etc. can also be used.

(Function) When the drying inhibitor according to the present invention was added to printing ink, it was confirmed that hydroquinone existed in the ink in a dissolved state. In other words, especially when printed on an absorbent printing material such as paper, hydroquinone is in a dissolved state and is quickly absorbed into the printing material together with the petroleum solvent in the printing ink. There is no delay or suppression of drying of the printing ink film.

(Example) The present invention will be explained below with reference to Examples. In the examples, 2 parts means parts by weight, and 2% means % by weight.

Production Examples 1 to 12 (Preparation of Drying Inhibitor) Drying inhibitors for printing inks of the present invention were obtained by the following formulations.

(Left below) I Kuro - h'11 Yoguchi's 010's 0's Loli 0's lit co an co tyr c
o an co an co o> co
.

Teacher; ■■■■ in the last time N■! 20 Comparative production example Part by weight Compound
Weight part O ■ Ethanol 80 Hydroquinone 20380 p-nonylphenol 20 5
80 2-6-terLbutyl-4-methylphenol 207 Dipropylene glycol 80
p-nonylphenol 20 Monopropyl ether 9 Monoethylene glycol 80 2-6-di-te
r L-buty+1-4-methylphenol 20 monobutyl ether Examples 1-12. Comparative Examples 1 to 10 To 100 parts of commercially available oxidative polymerization type off-cent ink A (Toyo King New Bright G, manufactured by Toyo Ink Mfg. 91), 1 part of each of the drying inhibitors of Production Examples 1 to 12 was added and mixed. The drying time when printed on paper and the drying of the ink on the printing press roll were measured and the results shown in Table 1 were obtained. Moreover, the drying inhibitors of Comparative Production Examples 1 to 10 were also tested in the same manner, and the results are shown in Table 2.

For comparison purposes, the drying times on two papers and on a glass plate are also listed in the table for inks to which the drying inhibitor of the present invention was not added.

(Leaving space below) Table 1 Example Drying inhibitor Drying time Fish Production example Arashi On paper On glass plate Texture 1
1 2.5 hours 12 hours Same as additive-free product 2
2 2.3〃 6〃 〃3 3
2.5〃 12〃 〃4 4 2.3〃
6〃 〃5 5 2.5〃12〃〃 6 6 2.3〃 6〃 〃7
7 2.5〃12〃 Slightly inferior 8 8 2
．． 3〃 6〃 〃9 9 2.5〃
12〃 Same as additive-free product 10 10 2.3
〃6〃〃 11 11 2.5〃12〃〃12 1
2 2.3〃6〃〃 Ink A (not added) 2 hours 3 hours □Table 2 Comparative example Drying inhibitor Drying time Comparative manufacturing example On paper On glass plate Texture No.
.

1 1 2.5 hours 8 hours Same as additive-free product 2 2 2.3〃4〃〃 3 3 2.3〃 4〃 〃4
42 〃 3〃 〃5 5 3 〃
5〃 〃662.5〃 4〃 〃 7 7 2.5〃4.5〃〃 8 8 2.3〃 3.5〃 〃9
9 3.0〃5.5〃〃〃 10 10 2.5〃4〃〃〃 Examples 13 to 24 Printing was carried out on a sheet-fed offset monochrome machine using the inks of Examples 1 to 12, and the printing life of the PS plate was The number of sheets and the number of sheets with piling were investigated. After printing, the printing press was left for 12 hours without cleaning to see if it could be reprinted. The results are shown in Table 3.

Table 3 Example No., number of sheets to be printed Reprint Number of sheets with piling occurrence 13 (1) 10 or more sheets ○ No occurrence 14 (2) 〃O” 15 (3)〃O〃 16 (4) 〃O” 17 (5) 10 pieces or more ○ 1B
(6) 〃 ○ 〃19(
7)/10〃 20(8) 〃 ○ 〃2
H9) 8 or more sheets O22 (10)
〃 ○ 〃23(11) 1
0 pieces or more ○ 24 (12)
〃 ○ 〃Ink A 10 or more sheets × 〃Also. Table 4 shows the results of the same tests performed on the inks of Comparative Examples 1 to 10.

(Margin below) Table 4 Comparative Example No. Number of printed sheets Reprint Number of sheets with piling occurrence 11 (1) 10 sheets or more 0 1 sheets 12
(2)〃×3〃 13(3)〃×2〃 14(4) X4〃15(5)
〃× No occurrence 16 (6) ” x 5
17(7) s X #
18(8)〃X n19(9)〃×
〃 20 (10) ”
Comparative Examples 21 to 23 Hydroquinone (Comparative Example 2) was added to commercially available offset ink A.
1), p-octylphenol (Comparative Example 22) or 2
．． 6-tertbutyl-4-methylphenol (Comparative Example 23) was added as a powder in the same amount as in Example 1, and dispersed using a three-roll mill.

For these three types of ink, the drying time is 2.

We tested the number of printed sheets, page printing, and number of piled sheets.
The results are shown in Table 5.

Table 5 Comparative example Drying time Floor On paper On fi5 board Texture 21 2.
5 hours 8 hours Same as additive-free product22 2.2〃4〃
〃 23 3.0 4.5 〃 Comparative Example No. Number of sheets to be printed Reprint Number of sheets with pile-up occurrence 21.1 million sheets or more 010,000 sheets 22× No occurrence 23〃× Suppresses and delays the drying of the printing ink adhered to the surface of the printing ink in the container or the surface of each part of the printing machine during printing interruptions without suppressing or delaying the drying of the ink film on the printing material having the properties things became possible. By adding hydroquinone as a solution, compared to the conventional method of adding it as a powder, it has become possible to reduce the hydroquinone content in printing ink by approximately 60% when providing the same degree of drying suppression effect. . Additionally, since hydroquinone exists in the ink in a dissolved state, there is no problem with piling.

Claims (1)

[Scope of Claims] 1. A printing ink comprising a drying inhibitor for printing ink prepared by dissolving hydroquinone in one or more high-boiling point organic solvents. 2. The printing ink according to claim 1, wherein the high-boiling organic medium is a compound represented by the following general formula [I]. ▲There are mathematical formulas, chemical formulas, tables, etc.▼ [I] (However, R_1 in the above formula represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or a phenyl group, and R_2 represents -C_
Represents 2H_4- or -C_3H_6-, where n is 2 to
Represents an integer of 3. 3. The printing ink according to claim 2, wherein the high-boiling organic medium comprises a compound represented by the general formula [I] and a high-boiling organic solvent used in the printing ink.