JPH0924681A - Dampening water for lithographic printing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain dampening water for lithographic printing capable of substituting for isopropyl alcohol by a method wherein alkyl ether of low molecular weight propylene oxide which has not practically an interfacial active performance, is used. SOLUTION: The dampening wafer for lithographic printing contains a compound of the general formula A, and does not contain ethylene oxide and/or propylene oxide adduct of 2-ethyl-1.3-hexanediole, or ethylene oxide and/or propylene oxide adduct of acethylene alcohol or acethylene glycol. In the general formula, R indicates methyl group, ethyl group, n-propyl group or isopropyl group, and (n) indicates an integer of 4. A content of a compound of the general formula (A) in the dampening water is 0.1-10wt.% and preferably 1-7wt.%. When the content is less than 1wt.%, surface tension is not sufficiently decreased, and tinting and scumming will appeare on prints. When it exceeds 10wt.%, though rise of water is made good, this process is disadvantageous in the cost.

Description

Detailed Description of the Invention

[0001]

The present invention relates to a fountain solution 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 dampening solution is attached to the hydrophilic surface, the ink is attached to the oil-sensitive surface, and printing is performed using the mutual repulsion between the ink and the dampening solution. At this time, it is important that the ink and the fountain solution are supplied to the plate while maintaining an appropriate balance. If the dampening water is given too much, the emulsification of the ink becomes intense, which causes the back of the ink and poor drying. On the other hand, if the amount of the dampening solution is too small, the ink adheres to the non-image area and causes stains. To maintain the balance between the ink and the dampening solution, isopropyl alcohol (IPA) has been conventionally used as an additive to lower the surface tension into the dampening solution.
Is usually about 10% by weight, and various hydrophilic substances such as gum arabic and carboxymethyl cellulose (CM
C), citric acid, various surfactants, and other acids such as phosphoric acid have been added as surface modifiers for removing plate surface oxides, and ammonium dichromate and nitrates have been added as plate corrosion inhibitors. Advantages of the dampening solution using IPA are that a good printed matter is obtained and that the drainage is good, and as a result, the so-called water width becomes large and the workability is improved. The reason for this is
The addition of IPA makes the dampening solution wet well on the hydrophilic non-image area of the printing plate, and has good wettability on the dampening water supply roller. However, IPA is a flammable dangerous substance, so it is necessary to pay close attention to fire,
Since it is harmful to the human body, a lithographic dampening solution containing no harmful substances has been desired.

For this reason, for example, Japanese Patent Publication No. 55-19775
Japanese Patent Application Laid-Open No. 63-25093 discloses a lithographic printing dampening solution to which a propylene oxide or ethylene oxide alkyl ether surfactant is added, and JP-A-63-25093 discloses a lithographic printing dampening solution to which a polyethylene oxide surfactant is added. Shimizu was proposed. However, when the surface tension of the dampening solution is reduced by the addition of a surfactant, the surface tension is certainly lowered by the addition of about 0.1 to 0.5%, but compared with the dampening solution using IPA. The fountain solution was poorly drained, and uniform wetting of the plate on the hydrophilic non-image area was insufficient.

[0004] The present inventors have studied the above phenomenon, and as a result, even if the static surface tension is the same, in actual printing, the ink roller, the printing plate and the dampening solution supply roller are rotated at a high speed in actual printing. By presuming that there is a difference in dynamic surface tension, by using an alkyl ether of low molecular weight propylene oxide having substantially no surface active ability,
The present inventors have obtained a new finding that the above-mentioned problem is solved and completed the present invention. It is also conceivable to decrease the surface tension by increasing the amount of the surfactant added. However, in this case, there are disadvantages in that the ink is bladed or foaming becomes severe.

[0005]

An object of the present invention is to provide a fountain solution for lithographic printing which can be replaced with an isopropyl alcohol-based solution.

[0006]

According to the present invention, there is provided a compound represented by the general formula (A):

Embedded image (Wherein, R represents a methyl group, an ethyl group, an n-propyl group or an isopropyl group, and n represents an integer of 4), and ethylene oxide of 2-ethyl-1,3-hexanediol is contained. And / or a fountain solution for lithographic printing characterized in that it does not contain an ethylene oxide and / or propylene oxide adduct of propylene oxide adduct or acetylene alcohol or acetylene glycol.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The above compounds used in the present invention are usually used by adding 0.1 to 10% by weight to a fountain solution. This dampening solution has an upper limit temperature of 35 to 4 on a printing press.
At 0 ° C. and the amount added in this concentration range, the micelle forming ability is weak, and the behavior as a solvent similar to IPA is exhibited. As an additive for a fountain solution, for example, Japanese Patent Publication No. 19977/1979 proposes the use of an alkyl ether-based surfactant of propylene oxide. Since the addition mole number of propylene oxide is large, this fountain solution is used on a printing press. Upper limit temperature 35 ~
At 40 ° C., the cloudiness, which is a characteristic of a general nonionic surfactant, is low, so that the solubility is poor and its use is difficult. In contrast, the compound used in the present invention does not have such a thing,
The desired purpose can be achieved. The fountain solution of the present invention has a reduced dynamic surface tension, particularly good drainage by a Dahlgren type fountain solution supply device, can uniformly wet a hydrophilic non-image area, and has a foaming property. Also less.

The content of the compound of the formula (A) in the fountain solution is 0.1 to 10% by weight, preferably 1 to 7% by weight. When the content is less than 0.1% by weight, the surface tension is not sufficiently reduced, and the ink spreads to the surface of the dampening solution, causing floating stains and background stains on printed matter. On the other hand, if the content exceeds 10% by weight, the level of the dampening solution is increased to improve the viscosity. However, this is disadvantageous in terms of cost, and further increase of the content is not desirable. When R of the compound of the general formula (A) is a butyl group or more, and n is 5 or more, not only poor solubility in water makes it difficult to achieve a desired purpose, but also a poor boiling point on the printed surface due to a high boiling point. It is not preferable because it causes set-off.

In the fountain solution of the present invention, gum arabic, dextrin, sodium alginate, carboxymethylcellulose, hydroxymethylcellulose, polyvinyl alcohol, polyvinylpyrrolidone, polyacrylic acid, polyacrylamide and the like are further contained as desensitizers for plate surface protection. May be used. Also, depending on the purpose, nitric acid,
Sulfuric acid, phosphoric acid, citric acid, acetic acid, tartaric acid and their sodium, potassium, magnesium salts, etc., and ammonium bichromate, etc., and if necessary, preservatives and anionic, cationic, nonionic, etc. A surfactant or the like may be used.

[0010]

Next, the present invention will be described in detail with reference to comparative examples and examples. Unless otherwise specified, the middle part of an example shows a weight part.
Fountain solutions having the formulations shown in Examples 1 to 10 and Comparative Examples 1 to 7 were produced, and the properties of these, such as ink bleed, were measured. Further, a printing test was performed, and a water width, a printing stain, and the like were measured.

Example 1 9493 parts of water 500 parts of tripropylene glycol monomethyl ether 500 parts of phosphoric acid 1 part 1 part of magnesium nitrate 5 parts of gum arabic

Example 2 9493 parts of water 500 parts of tetrapropylene glycol monomethyl ether 500 parts of phosphoric acid 1 part of magnesium nitrate 1 part of gum arabic 5 parts

Example 3 9493 parts of water 500 parts of tripropylene glycol monoethyl ether 500 parts of phosphoric acid 1 part of magnesium nitrate 1 part of gum arabic 5 parts

Example 4 9493 parts of water 500 parts of tripropylene glycol monoisopropyl ether 500 parts of phosphoric acid 1 part 1 part of magnesium nitrate 5 parts of gum arabic

Example 5 9493 parts of water 250 parts of tripropylene glycol monoethyl ether 250 parts of tripropylene glycol monomethyl ether 250 parts of phosphoric acid 1 part of magnesium nitrate 1 part of gum arabic 5 parts

Example 6 9493 parts of water 250 parts of dipropylene glycol monopropyl ether 250 parts of dipropylene glycol monoethyl ether 250 parts of phosphoric acid 1 part of magnesium nitrate 1 part of gum arabic 5 parts

Example 7 Water 9842 parts Propylene glycol monomethyl ether 150 parts Polyoxyethylene / polyoxypropylene block copolymer (Emulgen PP-230, trade name, manufactured by Kao Corporation) 1 part Phosphoric acid 1 part Magnesium nitrate 1 part Arabic gum 5 copies

Example 8 Water 9962 parts Propylene glycol mononormal propyl ether 30 parts Polyoxyethylene / polyoxypropylene block copolymer (Emulgen PP-230, trade name of Kao Corporation) 1 part Phosphoric acid 1 part Magnesium nitrate 1 part Arabic gum 5 parts

Example 9 Water 9942 parts Dipropylene glycol monoethyl ether 50 parts Polyoxyethylene / polyoxypropylene block copolymer (Emulgen PP-230, trade name of Kao Corporation) 1 part Phosphoric acid 1 part Magnesium nitrate 1 part Arabic gum 5 parts

Example 10 9953 parts of water 40 parts of tetrapropylene glycol monoisopropyl ether 1 part of phosphoric acid 1 part of magnesium nitrate 1 part of gum arabic 5 parts

Comparative Example 1 8993 parts of water 1000 parts of isopropyl alcohol 1 part of phosphoric acid 1 part of magnesium nitrate 1 part of gum arabic 5 parts

Comparative Example 2 Water 9943 parts Ethylene glycol monobutyl ether 50 parts Phosphoric acid 1 part Magnesium nitrate 1 part Arabic gum 5 parts

Comparative Example 3 Water 9893 parts Polyoxyethylene / polyoxypropylene block copolymer (Emulgen PP-230, trade name of Kao Corporation) 100 parts Phosphoric acid 1 part Magnesium nitrate 1 part Arabic gum 5 parts

Comparative Example 4 Water 9982 parts Dialkyl sulfosuccinic acid sodium salt 10 parts Polyoxyethylene sorbitan monolaurate (Reodol TW: L106, trade name, manufactured by Kao Corporation) 1 part Phosphoric acid 1 part Magnesium nitrate 1 part Arabic gum 5 Department

Comparative Example 5 9493 parts of water 500 parts of triethylene glycol monomethyl ether 500 parts of phosphoric acid 1 part of magnesium nitrate 1 part of gum arabic 5 parts

Comparative Example 6 9493 parts of water 500 parts of tripropylene glycol 500 parts of phosphoric acid 1 part of magnesium nitrate 1 part of gum arabic 5 parts

Comparative Example 7 9493 parts of water 500 parts of propylene glycol monobutyl ether 500 parts of phosphoric acid 1 part of magnesium nitrate 1 part of gum arabic 5 parts

The pH of the fountain solution of these Examples and Comparative Examples was
Table 1 shows the results of measurement of surface tension, ink bleed, and odor. Ink bleed: Toyo Ink Manufacturing Co., Ltd. T
The K mark V-M (offset printing ink) indicates the degree of ink scattering when dropped, and the determination is based on the following criteria. The fountain solution of Comparative Example 7 was cloudy and was considered to have no apparent effect, and was excluded from the judgment. ：: The ink does not scatter on the dampening solution at all. X: The ink scatters on the dampening solution. Surface tension: Kyowa CBVP SURFACE TENSIOM manufactured by Kyowa Science Co., Ltd.
The average value measured three times at 25 ° C. or lower using ETER A-3 is shown. pH: Average value measured three times at 25 ° C. or lower using MODEL HM-7E manufactured by Toa Denpa Kogyo KK

Table 1 pH Surface tension Ink Odor dyne / cm bleed Example 1 4.7 40.4 ○ Example 2 4.7 37.6 ○ Example 3 4.8 31.9 ○ Example 4 4.7 28.0 ○ Example 5 4.8 29.0 ○ Example 6 4.7 33.2 ○ Example 7 4.8 43.0 ○ 例 Example 8 4.7 44.5 ○ Example 9 4.8 44.0 ○ Example 10 4.7 43.1 ○ Comparative Example 1 4.9 39.9 × × Comparative Example 2 4.7 49.5 × × Comparative Example 3 4.8 35.5 × Comparative Example 4 4.7 34 0.0 × Comparative Example 5 4.8 62.5 × Comparative Example 6 4.7 54.1 × ○ The determination of odor in Table 1 was made with x when there was an odor and with ○ when there was no odor.

Next, a printing test was performed using each fountain solution of Examples and Comparative Examples. The printing conditions are as follows. Printing machine: Mitsubishi Diamond I-4 (trade name, manufactured by Mitsubishi Heavy Industries, Ltd.) Printing speed: 10,000 revolutions / hour Paper: SK coat 4/6 90K (Sanyo Kokusaku Pulp)
(Trade name) dampening water Mechanism: Dahlgren method Temperature and humidity: 20-22 ° C, 40-50% RH Ink: TK Mark V Red-M (Toyo Ink Manufacturing Co., Ltd.)
(Production) Each dampening water was subjected to a printing test of 10,000 copies, and the degree of stains on the printed matter, the water width (note) and the degree of foaming were determined. Table 2 shows the results.

Table 2 Dirt Water Width Foaming of Printed Material Example 1 No Stain Occurrence 50 ○ Example 2 〃 50 ○ Example 3 ５０ 50 ○ Example 4 ５０ 50 ○ Example 5 実 施 50 ○ Example 6 ５０ 50 ○ Execution Example 7 ５０ 50 Example 8 〃 50 Example 9 〃 50 Example 10 ５０ 50 比較 Comparative Example 1 ４５ 45 比較 Comparative Example 2 Smearing / printing not possible 70 Comparative Example 3 １００ 100 XX Comparative Example 4 〃 100 XX Comparative Example 5 ７０ 70 ◎ Comparative Example 6 〃 100 ○

Note: Water width: The water dial value when the amount of water supplied to the plate surface is reduced and the printed matter is stained.
A smaller value indicates that the non-image area can be uniformly protected with a small amount of dampening water. Degree of foaming: ◎ …… No foaming …… Foaming is recognized, but there is no problem in printing ×× …… Foaming is severe and printing is difficult

The results in Tables 1 and 2 show that the fountain solution according to the invention has at least as good printability as the fountain solution with IPA. FIG. 1 shows the relationship between the Dahlgren water dial and the plate surface moisture content in Example 1, Comparative Example 1 and Comparative Example 3. As is clear from FIG. 1, the fountain solution of the present invention has significantly improved drainage,
The behavior was close to that of PA.

[0034]

According to the present invention, there is provided a fountain solution for lithographic printing having excellent printability equal to or better than fountain solution containing isopropyl alcohol which has been frequently used as a fountain solution for lithographic printing. You. According to the present invention, odor,
A fountain solution for lithographic printing having excellent suitability such as no ink bleed is provided. Further, according to the present invention, there is provided a fountain solution for lithographic printing, which has excellent printability such as no print stain, wide water width, good water drainage, and excellent wettability.

[Brief description of drawings]

FIG. 1 is a diagram showing the relation between a Dahlgren water dial and the water content of a plate to show the state of each dampening water in Example 1, Comparative Example 1 and Comparative Example 3.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Takeya Sakai 571 Sonobe, Wakayama City, Wakayama Prefecture (72) Inventor Toshio Sato 2 of 732 Sakata, Wakayama City, Wakayama Prefecture (72) Takashi Ito 1-chome Taito, Taito-ku, Tokyo No. 5 No. 1 Toppan Printing Co., Ltd. (72) Inventor Katsuhiro Osaki 1-5-1, Taito, Taito-ku, Tokyo No. 1 Toppan Printing Co., Ltd. (72) Inventor Masumi Takase 2-3 Kyobashi, Chuo-ku, Tokyo No. 13 Toyo Inki Manufacturing Co., Ltd.

Claims (3)

[Claims] 1. A compound of the general formula (A) (Wherein, R represents a methyl group, an ethyl group, an n-propyl group or an isopropyl group, and n represents an integer of 4), and ethylene oxide of 2-ethyl-1,3-hexanediol is contained. And / or a fountain solution for lithographic printing, which does not contain an ethylene oxide and / or propylene oxide adduct of propylene oxide adduct or acetylene alcohol or acetylene glycol. 2. A fountain solution for lithographic printing according to claim 1, wherein the compound of the formula (A) is contained in an amount of 0.1 to 10% by weight. 3. The fountain solution for lithographic printing according to claim 1, comprising 1 to 7% by weight of the compound of the formula (A).