JP2000281954A - Gel varnish for offset printing ink and offset printing ink composition using the same - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To satisfy the performance required for offset printing such as settability, drying properties, stains on a printing plate or blanket, and abrasion resistance while sufficiently suppressing misting and piling during high-speed printing. Provided are a gel varnish for offset printing ink to be obtained and an offset printing ink composition using the same. SOLUTION: The weight average molecular weight is 20,000 to 150,
Rosin-modified phenolic resin, a gelling agent,
A gel varnish for offset printing ink obtained by heating and reacting a mixture containing at least one selected from the group consisting of a solvent having a boiling point of 60 ° C. or higher and being incompatible with water, a drying oil and a semidrying oil, A gel varnish for offset printing inks, wherein the gelling agent is used in an amount of more than 5% by weight and not more than 20% by weight based on the rosin-modified phenol resin (solid content), and an offset printing ink using the same.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gel varnish for offset printing inks and an offset printing ink composition using the same, and particularly to a gel varnish for offset printing inks suitable for high-speed printing and an offset printing ink composition using the same.

[0002]

2. Description of the Related Art A varnish for a printing ink used in an offset printing ink composition is generally composed of a rosin-modified phenol resin heated and dissolved in a drying oil such as linseed oil, a semi-dry oil, a petroleum-based solvent, or the like. I have. In order to improve the printability by increasing the viscosity of the printing ink, a gel varnish that has been gelled by adding a gelling agent is generally used. For example, JP-A-57-61071, JP-A-1-292079, and JP-A-3-95
254, JP-A-4-132778, JP-A-8-283643, JP-A-10-88052 and the like, a gelling agent is added to a rosin-modified phenol resin or the like, and the mixture is heated to 140 to 240 ° C. To a gel varnish.

On the other hand, in recent years, the printing speed of a printing press has been increasing even in offset printing. However, as the printing speed of a printing press increases, misting and piling increase sharply. It is rare.

However, in the conventional offset printing ink composition using the gel varnish for offset printing ink, misting and piling of the printing ink during high-speed printing are sufficiently suppressed, and drying properties, abrasion resistance, setting properties, and the like are further improved. I could not be satisfied.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the prior art, and it has been found that missetting and piling during high-speed printing are sufficiently suppressed while setting properties, drying properties, stains on a printing plate and a blanket, and abrasion resistance. An object of the present invention is to provide a gel varnish for offset printing ink and an offset printing ink composition using the same, which can satisfy performance required for offset printing such as properties.

[0006]

Means for Solving the Problems The present inventors have made intensive studies to solve the above-mentioned problems, and as a result, a gelling agent was applied to a rosin-modified phenolic resin (solid content) in a varnish for offset printing ink. By using a gel varnish for offset printing ink which is blended in a high addition amount which has never been known before, that is, a high addition amount of more than 5% by weight and not more than 20% by weight in the offset printing ink composition, high speed can be achieved. While sufficiently suppressing misting and piling during printing, we found a new fact that it can satisfy the performance required for offset printing such as setability, drying properties, stains on plate surface and blanket, abrasion resistance,
The present invention has been completed.

That is, the present invention relates to (1) a rosin-modified phenol resin having a weight average molecular weight of 20,000 to 150,000, a gelling agent, a solvent having a boiling point of 160 ° C. or more and being incompatible with water, A gel varnish for offset printing ink obtained by heating and reacting a mixture containing at least one selected from the group consisting of oil and semi-drying oil, wherein the gelling agent is used in an amount of the rosin-modified phenolic resin (solid content). The present invention relates to a gel varnish for offset printing inks, which is more than 5% by weight and not more than 20% by weight.

[0008] The present invention also relates to (2) an offset printing ink composition characterized in that the offset printing ink composition contains 20 to 70% by weight of the gel varnish for offset printing ink described in (1) above. .

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The above-mentioned patent documents only describe the addition of a gelling agent to a varnish for offset printing ink to form a gel varnish as a conventional technique in the technical field. The invention according to the invention has no feature in the use of a gelling agent, and there has been no detailed study on the use of the gelling agent from the beginning, and the amount of the gelling agent used for the rosin-modified phenolic resin and the misting and piling of Nothing shows a relationship with the suppression effect. For example, the invention disclosed in Japanese Patent Application Laid-Open No. 4-132778 is intended to improve the drying property by blending a resin with a urethane oil having an oil length of 40 to 90%. Although a phenol resin is used, the amount of the gelling agent used is only 5% by weight based on the resin. In addition, Japanese Patent Application Laid-Open No. 8-283643
The invention according to the gazette is to improve the on-paper drying property and on-machine drying property by using a small amount of phenol resin in combination with the rosin-modified phenol resin, the gelling agent for the rosin-modified phenol resin in Examples The amount used is only about 2% by weight. Japanese Patent Application Laid-Open No. 10-88052
The invention according to the gazette is intended to improve the high-speed printing suitability such as misting suppression at the time of high-speed printing by improving the rosin-modified resin by obtaining a rosin-modified resin by a solution polymerization method. The amount of gelling agent used is at most only about 2% by weight. In other patent documents as well, the amount of the gelling agent used for the resin is, as can be seen from the examples, a very small amount of about 3% by weight or less based on the resin solid content in the printing varnish. It is.

In the present invention, however, a gelling agent is added to a rosin-modified phenol resin varnish (solid content) in a conventional manner to obtain a gel varnish for offset printing ink by adding a gelling agent to the rosin-modified phenol resin varnish. When blended in a high addition amount of more than 20% by weight and not more than 20% by weight, surprisingly, misting and piling are sufficiently suppressed at the time of high-speed printing, and the setting property, drying property, dirt on the plate surface and blanket, and abrasion resistance are surprisingly high. It has been found a completely new fact that the performance required for offset printing can be satisfied.

Hereinafter, the gel varnish for offset printing ink and the offset printing ink composition using the same according to the present invention will be described in more detail.

The rosin-modified phenolic resin used for obtaining the gel varnish for offset printing ink of the present invention has a weight average molecular weight of 20,000 to 150,000.
If it is 0, a rosin-modified phenol resin conventionally used can be used without any particular limitation. If the weight-average molecular weight of the rosin-modified phenolic resin is less than 20,000, misting is not improved in offset printing, while if it is more than 150,000, there is a problem that troubles during production are likely to occur.

If the acid value and hydroxyl value of the rosin-modified phenolic resin are too high, the water resistance of the resulting printing ink is lowered, and offset printing tends to cause troubles such as stains. If the value of the hydroxyl value is too low, the unreacted gelling agent will remain, and the temporal stability of the obtained offset printing ink composition tends to deteriorate. It is preferable to select a rosin-modified phenolic resin having the same.

The rosin-modified phenolic resin usable in the present invention includes, for example, rosins or derivatives thereof,
Phenolaldehyde addition condensate (so-called resol)
And, if necessary, a reaction with a polyhydric alcohol. Here, rosins or derivatives thereof refer to rosins or carboxyl group-containing derivatives thereof. Examples of rosins include gum rosin, wood rosin, tall oil rosin, disproportionated rosin, hydrogenated rosin and polymers thereof, and carboxyl group-containing derivatives thereof include unsaturated acids such as maleic acid, itaconic acid and crotonic acid. Rosin derivatives to which a carboxylic acid has been added can be given.

The phenols used in the phenol aldehyde addition condensate include phenol and a phenol having 1 to 1 carbon atoms.
Alkyl-substituted phenols substituted with 20 linear, branched or cyclic alkyl groups, such as p-cresol, m-
Cresol, p-propylphenol, p-tert-
Butylphenol, p-amylphenol, p-cyclohexylphenol, p-tert-octylphenol, p-nonylphenol, p-decylphenol, p
Alkyl-substituted phenols such as dodecylphenol,
Examples include aromatic group-substituted phenols such as phenylphenol and cumylphenol, and polyhydric phenols such as catechol, resorcin, hydroquinone, bisphenol A, bisphenol S, and bisphenol F.

As a method for producing a corresponding phenol aldehyde addition condensate using the phenols, a method in which the phenols and the aldehydes are heated and reacted in an aqueous or organic solvent in the presence of an alkali catalyst, that is, resole A method for producing a phenolic resin, or a phenol and an aldehyde are heated and reacted in an aqueous or organic solvent in the presence of an acid catalyst to first produce a novolak phenolic resin, and then in the presence of an aldehyde and an alkali catalyst. And a method for obtaining a resolated phenolic resin by heat reaction.

The aldehydes used include formaldehyde, paraformaldehyde, acetaldehyde, propionaldehyde, n-butyraldehyde, isobutyraldehyde, glyoxazole and furfural, and the like.
Examples of the acid catalyst include potassium hydroxide and calcium hydroxide, and examples of the acid catalyst include acetic acid, hydrochloric acid, phosphoric acid, hypophosphorous acid, sulfuric acid, p-toluenesulfonic acid, trifluoromethylsulfuric acid, and trifluoromethylacetic acid. As the preferable degree of polymerization of the phenol resin obtained here, those having at least 2 phenol nuclei, more preferably 3 phenol nuclei are preferable from the viewpoint of solubility.

Examples of polyhydric alcohols include glycerin, trimethylolethane, trimethylolpropane, ethoxylated trimethylolpropane, propoxylated trimethylolpropane, neopentyl glycol, pentaerythritol, dipentaerythritol, sorbitol,
Examples include aliphatic polyhydric alcohols such as 1,6-hexanediol, ethylene glycol, diethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, and polypropylene glycol.

The rosin-modified phenolic resin which can be used in the present invention comprises the above-mentioned rosin, resole and, if necessary, polyhydric alcohol in any order at an elevated temperature, preferably in a temperature range of 150 to 300 ° C. It can be obtained by causing a heat reaction. If necessary, an acid catalyst can be used in the reaction, and examples of such an acid catalyst include p-toluenesulfonic acid, dodecylbenzenesulfonic acid, methanesulfonic acid, and ethanesulfonic acid. In order to prevent coloring, a reducing agent such as hypophosphorous acid, triphenyl phosphite, triphenyl phosphate or the like can be used in combination. As a catalyst other than the acid catalyst, magnesium salts such as magnesium hydroxide, magnesium carbonate, magnesium bicarbonate, magnesium acetate, magnesium formate, and magnesium oxalate can also be used. Furthermore, the pressure can be reduced to promote the condensation reaction.

Further, rust of the metal can be prevented by neutralizing hydrogen ions derived from the remaining acid catalyst and the like. As the neutralizer, hydroxides, oxides or salts of carboxylate salts of metals such as lithium, cesium, magnesium, calcium, strontium, barium, aluminum, zinc, titanium, zirconium, antimony, and selenium can be used. is there.

The content of the rosin-modified phenolic resin in the gel varnish for offset printing ink of the present invention is not particularly limited, but is usually in the range of 25 to 50% by weight.

Examples of the gelling agent used for obtaining the gel varnish for offset printing inks of the present invention include aluminum alcoholates, aluminum chelate compounds and the like. Preferred examples thereof include aluminum triisopropoxide, monosec. -Butoxyaluminum diisopropoxide, aluminum trisec-butoxide, ethyl acetoacetate aluminum diisopropoxide, aluminum trisethyl acetoacetate, and the like.

In the present invention, the use amount of the gelling agent with respect to the rosin-modified phenol resin (solid content) for obtaining the gel varnish is very important, and the use amount of the gelling agent depends on the rosin-modified phenol resin (solid content). Over 5% by weight and 20
% Or less, preferably 6 to 20% by weight. If the amount of the gelling agent is less than the above range, in the offset printing, the effect of suppressing misting and piling is not sufficient,
In addition, there are problems such as insufficient setability, drying properties, stains on the printing plate and blanket, and abrasion resistance. On the other hand, when the ratio exceeds the above range, there is a problem such as deterioration in temporal stability. However, since the appropriate amount of the gelling agent varies depending on the rosin-modified phenol resin used, it is preferable to select an appropriate amount within the above range. In addition, since there is a limit amount at which the gelling reaction proceeds sufficiently for each rosin-modified phenol resin used, it is preferable to set an appropriate value for each.

The drying oil or semi-drying oil used for obtaining the gel varnish for offset printing ink of the present invention includes soybean oil, cottonseed oil, linseed oil, safflower oil, tung oil,
Tall oil, dehydrated castor oil, canola oil and the like can be exemplified.

As the solvent used for obtaining the gel varnish for offset printing inks of the present invention, those having a boiling point of 160 ° C. or higher, preferably 200 ° C. or higher, which are incompatible with water can be suitably used. Specifically, n-paraffinic solvents, isoparaffinic solvents, naphthenic solvents, aromatic solvents, petroleum solvents such as α-olefins, gas oils, which are generally used as offset printing ink solvents,
Spindle oil, machine oil, cylinder oil, turpentine oil,
Mineral split can be exemplified.

In the gel varnish for offset printing ink of the present invention, either the oil component or the solvent component may be used, or both may be used in combination.

In order to obtain the gel varnish for offset printing ink of the present invention using the above materials, the weight average molecular weight is from 20,000 to 150,000, for example, by the following method.
A rosin-modified phenolic resin, a gelling agent of more than 5% by weight to 20% by weight based on the rosin-modified phenolic resin (solid content), a solvent having a boiling point of 160 ° C. or more and incompatible with water, and a drying oil. And at least one selected from the group consisting of semi-drying oils and a heating reaction.

Weight average molecular weight 20,000 to 150,
A rosin-modified phenolic resin having a boiling point of 160 ° C. or higher and a water-insoluble solvent having a boiling point of not less than 5% by weight and not more than 20% by weight based on the rosin-modified phenolic resin (solid content); A mixture comprising at least one selected from the group consisting of oils and semi-drying oils from 150 to 300
A gel varnish for offset printing ink is obtained by performing a heating reaction at 30 ° C. for about 30 minutes to 2 hours.

The weight average molecular weight is from 20,000 to 150,
A rosin-modified phenolic resin having a boiling point of 160 ° C. or more and at least one selected from the group consisting of a solvent which is incompatible with water, a drying oil and a semi-drying oil is used for 150-30.
After heating at 0 ° C. to dissolve the rosin-modified phenolic resin,
5% by weight based on the rosin-modified phenol resin (solid content)
Over 20% by weight of a gelling agent.
A gel varnish for offset printing ink is obtained by performing a heating reaction at 30 ° C. for about 30 minutes to 2 hours.

In the gel varnish for offset printing inks of the present invention, a resin other than the rosin-modified phenolic resin can be used in combination as long as the performance is not reduced, if necessary. Examples of such a resin component include various alkyd resins, petroleum resins, rosin ester resins, polyester resins, Gilsonite, or modified products thereof.

Next, the offset printing ink composition containing the gel varnish for offset printing ink of the present invention will be described in detail.

The offset printing ink composition of the present invention comprises:
By containing the specific gel varnish, misting and piling are significantly suppressed in a high-speed printing machine as compared with conventional offset printing inks, and setting properties, drying properties, stains on a plate surface or a blanket, abrasion resistance, etc. Is good without deteriorating the performance required for the offset printing.

The content of the specific gel varnish in the offset printing ink composition of the present invention is 20 to 70% by weight. If the high-density gel varnish is less than 20% by weight, there is a problem that an effect of improving performance required for offset printing, such as suppression of misting, cannot be obtained. On the other hand, when the content of the specific gel varnish exceeds 70% by weight, there is a problem that an appropriate viscosity-tack balance as an ink cannot be obtained.

As the colorant for obtaining the offset printing ink composition of the present invention, a colorless or colored inorganic or organic pigment generally used for offset printing inks can be used. Inorganic pigments such as barium sulfate, calcium carbonate, magnetic iron oxide, azo pigments, lake pigments, phthalocyanine pigments, isoindoline pigments,
Organic pigments such as anthraquinone pigments and quinacridone pigments,
The content of the colorant in the offset printing ink composition in which carbon black or the like can be used is suitably about 6 to 30% by weight.

As the drying oil and / or semi-drying oil that can be used to obtain the offset printing ink composition of the present invention, those similar to those used to obtain the gel varnish for offset printing ink can be used.

The solvent which can be used for obtaining the offset printing ink composition of the present invention includes a boiling point of 16 which is incompatible with water used as a solvent for offset printing ink.
Those having a temperature of 0 ° C or higher, preferably 200 ° C or higher can be used. Specifically, the same solvents as those used for obtaining the gel varnish for offset printing ink can be exemplified.

Further, the offset printing ink composition of the present invention may contain additives such as a pigment dispersant, a dryer, a drying retarder, an antioxidant, a surface conditioning aid, a set-off inhibitor, and a nonionic surfactant. Can be used as appropriate.

For producing the offset printing ink composition of the present invention, a conventionally known method can be used. Hereinafter, a production method generally used for obtaining the offset printing ink composition of the present invention will be described.

To the gel varnish for offset printing ink of the present invention, a colorant, and if necessary, a drying oil and / or a semi-drying oil, a solvent, a pigment dispersant, and a resin varnish that can be used in combination, are added to a bead mill or a three-roll mill. The base for offset printing ink is obtained by dispersing the meat in the above manner.

In the base for offset printing ink,
If necessary, other additives such as resin varnish and wax which can be used together are added, and the viscosity is adjusted to a predetermined viscosity with a drying oil and / or a semi-dry oil, a solvent or the like to obtain an offset printing ink composition.

The offset printing ink composition of the present invention comprises:
It is suitably used for high-speed offset printing presses. In particular, misting and piling are sufficiently suppressed even in a high-speed offset printing press having a printing speed of 9 m / s or more, and even 12 m / s or more. Of course, the offset printing ink composition of the present invention has no problem even when used in a low-speed printing machine.

[0042]

EXAMPLES Hereinafter, the gel varnish for offset printing ink and the offset printing ink composition using the same according to the present invention will be described in more detail with reference to examples, but the present invention is not limited thereto unless it departs from the gist and scope of application. It is not limited. In the following description, "parts" indicates parts by weight.

[Production of varnish for offset printing ink] Examples 1 to 5 A four-necked flask equipped with a condenser, a thermometer and a stirrer was charged with a weight average molecular weight of 34,000 and an acid value of 11.1 m.
gKOH / g, rosin-modified phenolic resin A having a hydroxyl value of 55 mgKOH / g (manufactured by Arakawa Chemical Industry Co., Ltd.), linseed oil, and mineral oil (No. 5 solvent manufactured by Nippon Oil Co., Ltd.) (The blending amount of each component is indicated by the number of parts, the same shall apply hereinafter), the temperature was raised to 200 ° C., and the mixture was heated and dissolved at the same temperature for 1 hour, and then ethyl acetoacetate aluminum diisopropoxide (gelling agent) was used. (ALCH manufactured by Kawaken Fine Chemicals Co., Ltd.) were prepared so as to have the composition shown in Table 1, respectively, and heated and maintained at 175 ° C. for 30 minutes to obtain gel varnishes A to E for offset printing inks.

Example 6 A four-necked flask equipped with a condenser, a thermometer and a stirrer was charged with a weight average molecular weight of 35,000 and an acid value of 21.4 m.
A rosin-modified phenol resin B (manufactured by Harima Chemicals, Inc.) having a hydroxyl value of 135 mgKOH / g, linseed oil, and mineral oil having a hydroxyl value of 135 mgKOH / g were prepared so as to have the composition shown in Table 1, and then 200 ° C.
After heating and dissolving at the same temperature for 1 hour, ALCH was charged as a gelling agent so as to have the composition shown in Table 1, and 175 was added.
C. for 30 minutes to obtain a gel varnish F for offset printing ink.

Example 7 A gel varnish G for offset printing ink was prepared in the same manner as the gel varnish D for offset printing ink except that linseed oil was changed to soybean oil in the production of the gel varnish D for offset printing ink of Example 4. Obtained.

Example 8 In the production of gel varnish D for offset printing ink, linseed oil was converted to an alkyd resin (LV-192 manufactured by Rotor Inc.).
A gel varnish H for offset printing ink was obtained in the same manner as in the preparation of gel varnish D for offset printing ink except for changing to 5).

Example 9 A four-necked flask equipped with a condenser, a thermometer and a stirrer was charged with a weight average molecular weight of 130,000 and an acid value of 22.3.
rosin-modified phenolic resin C (manufactured by Hitachi Chemical Co., Ltd.) having a mgKOH / g and a hydroxyl value of 75 mgKOH / g;
Linseed oil and mineral oil were prepared so as to have the composition shown in Table 1.
After heating to 00 ° C. and heating and dissolving at the same temperature for 1 hour, ALCH was charged as a gelling agent so as to have a composition shown in Table 1,
The mixture was heated and maintained at 175 ° C. for 30 minutes to obtain a gel varnish I for offset printing ink.

Example 10 In a four-necked flask equipped with a condenser, a thermometer and a stirrer, rosin-modified phenolic resin A and soybean oil were charged so as to have the composition shown in Table 1, and the temperature was raised to 200 ° C.
After heating and dissolving for 1 hour, ALCH was used as a gelling agent in Table 1.
And heated and maintained at 175 ° C. for 30 minutes to obtain a gel varnish J for offset printing ink.

Example 11 A four-necked flask equipped with a condenser, a thermometer, and a stirrer was charged with rosin-modified phenolic resin A, rosin-modified phenolic resin C, linseed oil, and mineral oil so as to have the composition shown in Table 1. ° C, and dissolved by heating at the same temperature for 1 hour. Then, ALCH was charged as a gelling agent so as to have the composition shown in Table 1, and heated and maintained at 175 ° C for 30 minutes to obtain a gel varnish K for offset printing ink. .

Comparative Example 1 A rosin-modified phenolic resin A, linseed oil and mineral oil were charged into a four-necked flask equipped with a condenser, a thermometer and a stirrer so as to have the composition shown in Table 1, and the temperature was raised to 200 ° C. The mixture was heated and melted at the same temperature for 1 hour to obtain a varnish L for ink for comparative offset printing.

Comparative Examples 2 and 3 A rosin-modified phenolic resin A, linseed oil and mineral oil were charged into a four-necked flask equipped with a condenser, a thermometer and a stirrer so as to have the composition shown in Table 1, and the temperature was raised to 200 ° C. Then, after heating and dissolving at the same temperature for 1 hour, A is used as a gelling agent.
LCH was prepared so as to have the composition shown in Table 1, and at 175 ° C., 3
After heating and holding for 0 minutes, gel varnishes M and N for comparative offset printing inks were obtained.

[Production of Offset Printing Ink Composition] Examples 12 to 22 Gel Varnish A for Offset Printing Inks of Examples 1 to 11
To K, petroleum resin varnish, carbon black and extender were successively kneaded with a bead mill and three rolls in the composition shown in Table 2 to obtain each ink base. Next, a wax and a mineral oil were added to each ink base in the composition shown in Table 2, followed by stirring to obtain offset printing ink compositions of Examples 12 to 22.

Comparative Examples 4 to 6 Varnishes L to N for Offset Printing Inks of Comparative Examples 1 to 3,
Petroleum resin varnish, carbon black, and extender pigment were kneaded sequentially with a bead mill and three rolls in the composition shown in Table 2 to obtain each ink base. Then, for each ink base, Table 2
The wax and mineral oil were added and the mixture was stirred.
6 was obtained.

[Performance Evaluation Test] (1) 2.32 ml of the offset printing ink compositions of Examples 12 to 22 and Comparative Examples 4 to 6 were weighed and measured on a misting incometer (JIS K5701 4.2.2), and 30 ° C, 2400
The machine was operated for 2 minutes at rpm (peripheral speed of 9.0 m / s), and the misting amount at that time was judged from the weight of the ink adhered on the 10 cm × 10 cm paper spread under the vibration roll and the stain on the paper visually. Was evaluated based on the following criteria. Table 3 shows the results.

5: The paper has almost no stain and the weight of the mist ink is 10 mg or less. 4: The paper has little stain and the weight of the mist ink is 10 to 10.
30 mg 3: Medium stain on paper and weight of mist ink of 30
６０60mg 2: The paper is soiled a lot, and the weight of the mist ink is 60-1
00 mg 1: The paper is very dirty, and the weight of the mist ink is 100
mg or more

(2) Drying property The offset printing ink compositions of Examples 12 to 22 and Comparative Examples 4 to 6 were spread on art paper by a color spreader (JIS K5701 5.2.1) and heated to a predetermined temperature. The ink was passed through a drying oven set for 10 seconds, and the lowest oven temperature at which the ink became non-tacky was determined and evaluated based on the following criteria. Table 3 shows the results.

5: One that loses tackiness at 145 to 155 ° C 4: One that loses tackiness at 155 to 165 ° C 3: One that loses tackiness at 165 to 175 ° C 2: Loss of tackiness at 175 to 185 ° C Thing 1: Loss of tackiness at 185-195 ° C

(3) Transferability Using a printability tester (manufactured by Mitsui Electric Seiki Co., Ltd.), 0.15 cc of each of the offset printing ink compositions of Examples 12 to 22 and Comparative Examples 4 to 6 was printed at a printing speed of 9 It was spread on art paper at 0.9 m / s, and its transfer density was measured with a reflection densitometer (RD-918, manufactured by Macbeth), and evaluated based on the following criteria. Table 3 shows the results.

5: those having a transfer concentration of 1.7 to 1.8 4: those having a transfer concentration of 1.6 to 1.7 3: those having a transfer concentration of 1.5 to 1.6 2: Those having a transfer concentration of 1.4 to 1.5 1: Those having a transfer concentration of 1.3 to 1.4

(4) Printing Suitability Using a sheet-fed printing machine, if the water level gauge is changed, the printing paper surface, the plate, the blanket, and the like that are relatively superior to the soiling, and 5, An inferior thing was evaluated as 1. Table 3 shows the results.

<Printing conditions> Printing speed: 2 m / s Paper: NK High Coat (manufactured by Nippon Kaishi Paper Co., Ltd.) Wetting water: 2% cipher manufactured by Sakata Inx Co., Ltd.
No isopropyl alcohol added

(5) Friction Resistance The printed matter obtained in the above-mentioned printing suitability test was subjected to a load of 50 using a Gakushin type friction resistance tester manufactured by Daiei Kagaku Seiki Co., Ltd.
A friction test was performed under the conditions of 0 g and five strokes, the degree of rubbing of the printed matter was observed, and the evaluation was made based on the following criteria. Table 3 shows the results.

5: The printed matter is hardly rubbed 4: The printed matter is little rubbed 3: The printed matter is rubbed moderately 2: The printed matter is rubbed much 1: The printed matter is rubbed extremely much

(6) Printing test on high-speed web offset presses Using a high-speed web offset press, Examples 12 and 13
Printing tests were performed on the inks of Example 15, Example 17, and Comparative Example 6. Table 4 shows the results.

<Printing conditions> Printing speed: 12 m / s Paper: SPX-O (manufactured by Nippon Paper Industries Co., Ltd.) Dampening water: 2% cipher manufactured by Sakata Inx Co., Ltd.
No isopropyl alcohol added

<Evaluation Items> Misting A blank paper was pasted on the front of the kneading roll of the printing press, and 10
The misting amount at the time of printing every copy was visually observed and evaluated based on the following criteria.

5: Slightly soiled paper 4: Slightly soiled paper 3: Moderately soiled paper 2: Slightly soiled paper 1: Slightly soiled paper

Printing Suitability A relatively excellent one was evaluated as 5 and a relatively inferior one was evaluated as dirt on a printing paper surface, dirt on a plate or a blanket.

Abrasion Resistance The printed matter obtained in the above-mentioned printability test was subjected to a load of 50 using a Gakushin type friction resistance tester manufactured by Daiei Kagaku Seiki Co., Ltd.
A friction test was performed under the conditions of 0 g and five strokes, the degree of rubbing of the printed matter was observed, and the evaluation was made based on the following criteria.

5: The printed matter hardly rubs 4: The printed matter rubs little 3: The printed matter rubs moderately 2: The printed matter rubs much 1: The printed matter rubs very much

(7) Influence of peripheral speed on misting In the misting test of the above (1),
Using the offset printing ink compositions of 5, 17 and Comparative Examples 4 and 6, the peripheral speed of the incometer was 3.0 m / s,
The misting amount (weight of mist ink) at 6.0 m / s and 9.0 m / s was determined in the same manner as described above.
The results are shown in Table 5 and FIG.

(8) Influence of printing speed on transferability In the transferability test of (3), Examples 13 and 15
Using the offset printing ink compositions of Example 17 and Comparative Examples 4 and 6, the printing speed in a printability test apparatus was 3.3 m.
/ S, 6.6 m / s and 9.9 m / s were determined in the same manner as above. The results are shown in Table 6 and FIG.

[0073]

[Table 1]

[0074]

[Table 2]

[0075]

[Table 3]

[0076]

[Table 4]

[0077]

[Table 5]

[0078]

[Table 6]

[0079]

In offset printing at the time of high-speed printing,
By using the offset printing ink composition containing the gel varnish for offset printing ink of the present invention, misting can be significantly reduced as compared with the case of using the conventional offset printing ink composition. Also, set properties,
At the same time, the performance required for offset printing, such as drying properties, stains on the printing plate and blanket, piling, and abrasion resistance, is also very good.

[Brief description of the drawings]

FIG. 1 is a graph showing a relationship between a peripheral speed of an ink roller of a printing press and misting.

FIG. 2 is a graph showing the relationship between printing speed and transferability.

Continuing on the front page (72) Inventor Akihisa Sato 1-23-37 Edobori, Nishi-ku, Osaka-shi Inside Sakata Inks Co., Ltd. (72) Inventor Tomohide Kato 1-23-37 Edobori, Nishi-ku, Osaka-shi Inside Sakata Inks Co., Ltd. (72 ) Inventor Takashi Iwase 1--23-37, Edobori, Nishi-ku, Osaka-shi F-term in Sakata Inc. Co., Ltd. AB08 AE02 AF01 BC02 BC03 BE12 BE23 CA07 EA10 EA36 GA02

Claims (2)

[Claims] A weight average molecular weight of 20,000 to 150,
Rosin-modified phenolic resin, a gelling agent,
A gel varnish for offset printing ink obtained by heating and reacting a mixture containing at least one selected from the group consisting of a solvent having a boiling point of 60 ° C. or higher and being incompatible with water, a drying oil and a semidrying oil, A gel varnish for offset printing inks, wherein the amount of the gelling agent used is more than 5% by weight and not more than 20% by weight based on the rosin-modified phenol resin (solid content). 2. The offset printing ink composition according to claim 1, wherein the gel varnish for offset printing ink is 20 to 7 in an offset printing ink composition.
An offset printing ink composition containing 0% by weight.