JP6580374B2 - Method for producing penetrating dry offset printing ink composition - Google Patents

Description

  The present invention relates to a method for producing an ink composition for osmotic drying type offset printing.

  Offset printing is a printing method that utilizes the property that an oil-based ink composition for offset printing (hereinafter referred to as “ink composition” or “ink” as appropriate) repels water, and has unevenness. Unlike the relief printing method using a plate, a printing plate having no irregularities is used. This printing plate is provided with an oleophilic image portion and a hydrophilic non-image portion in place of the unevenness. In printing, first, the non-image portion of the printing plate is wetted with dampening water to form a water film on the surface, and then the ink composition is supplied to the printing plate. At this time, the supplied ink composition does not repel and adhere to the non-image area where the water film is formed, but adheres only to the oleophilic image area. Thus, an image of the ink composition is formed on the surface of the printing plate, and then printing is performed by sequentially transferring it to the blanket and paper.

  In addition, offset printing has a characteristic that it is suitable for the field of obtaining a printed material having a high cosmetic property and a large amount of printed material in a short time, although the production of a printing plate is relatively simple. Therefore, offset printing is widely used from fields requiring high cosmetics such as brochures, posters, and calendars to fields requiring high-speed and large-scale printing such as newspapers, magazines, and telephone books. .

  Of these fields, an offset rotary press is generally used in fields that require high-speed and large-volume printing. In the offset rotary press, the printing paper is mounted on the paper supply unit in a wound state, and the winding is unwound to supply the printing paper to the printing unit for printing. The printed printing paper is subjected to necessary processing such as folding after being cut by a cutting section to become a product. According to such a printing method, printing of about tens of thousands to hundreds of thousands of copies can be performed at a time, which is efficient, and the printing speed can reach as high as 100,000 copies per hour or more. is there.

  Newspaper printing, one of the typical fields of high-speed printing, uses the high-speed printing technology as described above, and prints using a osmotic drying ink composition on the additional paper, which is a relatively low-grade printing paper. I do. Renewal paper for newspaper printing has excellent oil absorption properties that allow oil to penetrate into the inside of the paper, so when an oily ink composition is printed on its surface, the oil components contained in the ink composition are quickly removed from the inside. Infiltrate. As a result, the ink composition that loses the oil component and loses its tackiness remains on the surface of the paper, and is in a so-called dry state. The time required for the process is very short. Therefore, even if the printing paper surface coming out from the offset rotary press is immediately folded into a booklet, the ink composition hardly adheres to the facing pages, and the newspaper Can be ensured as readability.

  As described above, the ink composition used for newspaper printing has technical demands to achieve both high-speed rotating offset rotary press and rapid drying by osmotic drying, and imparts high-speed printing suitability. Many products have been proposed (see, for example, Patent Document 1).

JP 2000-281945 A

  By the way, especially in color printing in newspapers, not all printed surfaces have the same size color design, and there are printed surfaces that contain large color designs as represented by full-scale advertisements. There are also printing surfaces that contain only small color symbols, as represented by the weather maps provided. On such a printed surface that contains only small color designs, for example, a weather map or the like is present on one printed surface, and only a news article (mainly black and white) is consumed. There are places where the color ink composition is not consumed. Then, in a portion where the color ink composition is not consumed, the color ink composition that has not been consumed stays on a roller for supplying ink, and sometimes also stays on a dampening roller that supplies dampening water to the printing plate.

  The ink composition staying on the roller is kneaded by the roller for a long time in contact with the fountain solution. Then, with the passage of time, the staying ink increases its viscosity and eventually becomes fixed on the roller. In this state, for example, when the printing press is stopped by replacing the printing plate, the ink composition fixed when the printing press is restarted adheres to the printing plate, or adheres to the blanket via the printing plate. Sometimes. The ink composition attached in this way has a very high viscosity, so if it adheres to the non-image area of the printing plate, it may not be removed easily from the printing plate even if dampening water is supplied, causing stain on the printing paper surface. In addition, if it adheres to the blanket, it may cause troubles such as the printing paper being rolled and cut.

  The phenomenon that the ink composition is fixed by increasing its viscosity is referred to as “nappa”, and is noticeable when the ink composition is kneaded for a long time by a roller in the presence of dampening water. The The present situation is that the response of the ink composition to such “sag” phenomenon is not yet sufficient. Further, such a phenomenon is particularly noticeable in a penetrating dry type ink composition for offset printing used in newspaper printing.

  The present invention has been made in view of the above situation, and it is an ink composition for osmotic dry offset printing that can maintain good printability even when printing is continued for a long time in offset printing. The purpose is to provide goods.

  As a result of intensive studies in order to solve the above problems, the present inventors prepared a pigment dispersion composition constituting the ink composition, and then added a bivalent or higher-valent metal alkoxy compound to the pigment dispersion composition. It was found that by adding them and raising the temperature to 70 to 200 ° C. to cause gelation, and using this as an ink composition, the “sagging” phenomenon during printing can be remarkably improved. The present invention has been made based on the above findings, and specifically provides the following.

The present invention provides a mixing step of preparing a pigment dispersion composition containing a pigment, a resin and an oil component, and the temperature of the pigment dispersion composition is 70 to 200 ° C. in a state where a bivalent or higher-valent metal alkoxy compound is added. to the gelling process, only including, at least a portion of the resin and the oil component, the above mixing step in a condition that heating and mixing are gelled varnishes in the presence of alkoxy compound of divalent or higher valent metal It is a process for producing an ink composition for osmotic drying type offset printing.

  The addition amount of the metal alkoxy compound is preferably 0.1 to 3.0 parts by mass with respect to 100 parts by mass of the pigment dispersion composition.

  The metal alkoxy compound is preferably a compound containing aluminum as a metal.

The metal alkoxy compound is preferably diisopropoxy aluminum ethyl acetoacetate represented by the following chemical formula.

  The resin and the oil component are preferably subjected to the mixing step in a state where the resin and the oil component are heated and mixed in the presence of a divalent or higher metal alkoxy compound to form a gelled varnish.

  ADVANTAGE OF THE INVENTION According to this invention, even if it is a case where printing is continued for a long time in offset printing, the ink composition for osmosis | dry_drying type | mold offset printing which can hold | maintain favorable printability is provided.

  Hereinafter, although one embodiment of a method for producing an ink composition for osmotic drying type offset printing of the present invention is shown and described in detail, the present invention is not limited to the following embodiment.

  The method for producing an ink composition for osmotic drying offset printing according to the present invention comprises a mixing step of preparing a pigment dispersion composition containing a pigment, a resin and an oil component, and a state in which an alkoxy compound of a bivalent or higher metal is added. And a gelation step in which the temperature of the pigment dispersion composition is set to 70 to 200 ° C. The production method of the present invention includes these two steps of the mixing step and the gelation step as essential, and has another step before and after these two steps, and further between these two steps. May be. These two steps do not necessarily have to be performed continuously, but the mixing step needs to be located before the gelation step.

  As is well known, an ink composition is prepared by mixing and dispersing a varnish obtained by dissolving a resin in an oil component and a pigment as a coloring component. At this time, when preparing the varnish to add the viscoelasticity required in offset printing to the ink composition, the resin is dissolved with an oil component, and then a divalent or higher metal alkoxy compound is added and heated. Thus, the resin molecules are cross-linked through polar groups such as carboxyl groups contained in the resin molecules, and the varnish is gelled. That is, it is a normal procedure to prepare an ink composition by mixing and dispersing a varnish that has been gelled in advance and a pigment.

  On the other hand, in the production method of the present invention, after preparing a pigment dispersion composition by mixing and dispersing the varnish and the pigment, gelation is performed by adding an alkoxy compound of a bivalent or higher metal to the pigment dispersion composition and heating. I do. That is, in the present invention, the gelation is not performed in the varnish state, but the pigment is dispersed, and the gelation is performed in a state just before becoming an ink composition. The present inventors have surprisingly found that the above-mentioned “sag” phenomenon is remarkably improved when printing is performed using an ink composition that has undergone such a preparation procedure, and the present invention has been completed. It is. Hereinafter, each step will be described.

[Mixing process]
First, the mixing process will be described. In this step, a pigment dispersion composition containing a pigment, a resin and an oil component is prepared. First, each raw material will be described.

  The resin is a component that functions as a binder for fixing a color pigment, which will be described later, on the surface of the printing paper, and is also a component that is used for dispersing such a color pigment or the like in the ink composition. Examples of such resins include those usually used in the field of ink compositions without any particular limitation, and include rosin-modified phenol resins, rosin-modified maleic resins, rosin-modified alkyd resins, rosin-modified petroleum resins, and rosin esters. Examples thereof include resins, petroleum resin-modified phenol resins, acrylic-modified phenol resins, alkyd resins, vegetable oil-modified alkyd resins, and petroleum resins. The weight average molecular weight of these resins is preferably about 3000 to 300,000.

  Among these resins, from the viewpoint of pigment dispersibility, print quality and stable printability over a long period of time, from the group consisting of a rosin-modified phenolic resin and a rosin-modified maleic resin having a weight average molecular weight of 10,000 to 150,000. It is preferable to use at least one selected. In order to improve the dispersibility of the pigment, it is also preferable to use these resins and alkyd resins in combination. In this case, it is preferable to use about 3 to 10 parts by mass of the alkyd resin with respect to 100 parts by mass in total of the rosin modified phenolic resin and the rosin modified maleic resin. The amount of resin added is preferably about 10 to 35% with respect to the entire ink composition.

  As already described, the resin is dissolved and heated to a varnish when heated together with an oil component described later. As described above, when the resin is dissolved to form a varnish, it is generally used by gelling the varnish by heating with a bivalent or higher metal alkoxy compound. In the present invention, the pigment is used in the varnish. Gelation is performed in the state of being mixed and dispersed into a pigment dispersion composition. The varnish for preparing this pigment dispersion composition may be a varnish in which the resin is dissolved in the oil component (so-called dissolution varnish), or may be bivalent or higher after the resin is dissolved in the oil component. A gelled varnish may be obtained by heating and mixing in the presence of the metal alkoxy compound. It is preferable to use the latter gelled varnish for the preparation of the pigment dispersion composition because the “slipping” phenomenon tends to be further suppressed in the resulting ink composition.

  As the varnish, it is possible to use a combination of a plurality of types having different types of resin and oil component, resin content, and the like. In this case, a dissolution varnish and a gelled varnish can be used in combination.

  As the content of the resin component in the varnish, about 30 to 60% by mass can be mentioned. However, the content of the resin required in the ink composition and the handling property as the varnish are appropriately set. That's fine. In addition, the heating temperature when the resin is dissolved in the oil component to form a varnish may be appropriately set in consideration of the solubility of the resin and the like, and may be about 100 to 250 ° C. As described above, when using a gelled varnish as part or all of the varnish to be used, a gelling agent such as a bivalent or higher metal alkoxy compound is added to the varnish obtained by dissolving the resin. And heating at about 100 to 200 ° C.

[Oil component]
The oil component is used to dissolve the resin to make a varnish or to adjust the viscosity of the ink composition. Examples of the oil component include vegetable oils and / or mineral oils, and those that have been used in the preparation of ink compositions so far can be used without particular limitation.

  In the present invention, the vegetable oil may contain a vegetable oil-derived fatty acid ester compound in addition to the vegetable oil. Examples of vegetable oils include dry oils such as soybean oil, cottonseed oil, linseed oil, safflower oil, tung oil, tall oil, dehydrated castor oil, and canola oil, and semi-dry oils. Examples of the fatty acid ester compound derived from vegetable oil include monoalkyl ester compounds of fatty acids derived from the vegetable oil. As the fatty acid constituting the fatty acid monoalkyl ester compound, a saturated or unsaturated fatty acid having 16 to 20 carbon atoms is preferably exemplified, and as such a saturated or unsaturated fatty acid, stearic acid, isostearic acid, hydroxystearic acid, Preferred examples include oleic acid, linoleic acid, linolenic acid, eleostearic acid and the like. As the alkyl group constituting the fatty acid monoalkyl ester compound, an alkyl group having 1 to 10 carbon atoms is preferably exemplified, and more specifically, methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, Preferred examples include a tert-butyl group and 2-ethylhexyl group.

  These vegetable oils can be used alone or in combination of two or more. Preferred vegetable oils include soybean oil and soybean oil fatty acid ester. As content of the vegetable oil in an ink composition, about 20-60 mass% can be illustrated with respect to the whole ink composition.

  In the present invention, examples of the mineral oil include light mineral oil called a solvent and heavy mineral oil that is a lubricating oil. The use of heavy mineral oil is preferable because the “sag” phenomenon can be further suppressed.

  Examples of the light mineral oil include non-aromatic petroleum solvents having a boiling point of 160 ° C. or higher, preferably a boiling point of 200 ° C. or higher. Examples of such non-aromatic petroleum solvents include No. 0 Solvent, AF Solvent No. 5, AF Solvent No. 6 and AF Solvent No. 7 manufactured by JX Nippon Oil & Energy Corporation.

  Examples of heavy mineral oils include various lubricating oils that have been classified as spindle oil, machine oil, dynamo oil, cylinder oil, and the like. Among these, from the viewpoint of adapting to the OSHA standard and EU standard in the United States, it is preferable that the content of the condensed polycyclic aromatic component is suppressed. Examples of such mineral oils include Ink Oil H8 and Ink Oil H35 (all trade names) manufactured by JX Nippon Oil & Energy Corporation, SNH8, SNH46, SNH220, and SNH540 manufactured by Sankyo Oil Chemical Co., Ltd. (Both are trade names).

  These mineral oils can be used alone or in combination of two or more. As content of the mineral oil in an ink composition, about 0-50 mass% can be illustrated with respect to the whole ink composition. In addition, when it conforms to the Eco Mark standard (type name: printing ink version 2.8, standard: petroleum-based solvent in the ink composition is 30% by mass or less) approved by the Japan Eco Mark Secretariat. From the above viewpoint, the content of mineral oil in the ink composition is preferably 30% by mass or less.

[Pigment]
Pigments are classified into coloring pigments that impart coloring power to the ink composition and extender pigments that impart printing suitability such as viscoelasticity to the ink composition. In the present invention, a coloring pigment for imparting coloring power is used as an essential component, and an extender is used as an optional component. Next, these pigments will be described.

  Examples of the color pigment include organic and / or inorganic pigments conventionally used in ink compositions without any limitation.

  Examples of such coloring pigments include yellow pigments such as disazo yellow (Pigment Yellow 12, Pigment Yellow 13, Pigment Yellow 17, and Pigment Yellow 1), Hansa Yellow, and magenta pigments such as Brilliant Carmine 6B, Lake Red C, and Watching Red. And cyan pigments such as phthalocyanine blue, phthalocyanine green and alkali blue, and black pigments such as carbon black.

  The addition amount of the color pigment is exemplified by about 8 to 30% by mass with respect to the entire ink composition, but is not particularly limited. A yellow ink composition using a yellow pigment, a magenta ink composition using a magenta pigment, a cyan ink composition using a cyan pigment, and a black ink composition using a black pigment, respectively. When preparing, it is also possible to use a pigment of another color in combination or to add an ink composition of another color as a complementary color.

  Examples of extender pigments include clay, talc, kaolinite (kaolin), barium sulfate, calcium carbonate, silicon oxide, bentonite, and titanium oxide. The amount of extender added is exemplified by about 0 to 33% by mass with respect to the entire ink composition, but is not particularly limited.

  As the color pigment and the extender pigment (that is, the pigment), a press cake may be used or a powdery one may be used. Most of the pigments are synthesized in an aqueous system, and water is removed from the pigment obtained as a precipitate insoluble in water at the final stage of synthesis, and the resultant is used for preparing an ink composition. The first stage of the removal of water is filtration, and pigment particles are collected by filtration and pressure is applied to the water to squeeze out the water, which is called press cake. Since some moisture remains in the press cake, the weight increases, but the presence of moisture around the pigment particles suppresses aggregation of the pigment particles, and when preparing an ink composition, the pigment dispersion is reduced. The energy required can be reduced. On the other hand, when the pigment separated by filtration is dried, it becomes a powdery pigment. Unlike a press cake, a powdery pigment does not contain moisture, so the weight can be reduced. However, since pigment particles aggregate due to drying, energy required for pigment dispersion tends to increase. Which type of pigment is used may be appropriately determined in consideration of production facilities, handling, and the like.

  In this step, these materials are mixed to prepare a pigment dispersion composition. When preparing a pigment dispersion composition, as described above, it is common to previously use a resin and an oil component as a varnish, so the explanation here assumes that the resin and the oil component are used as a varnish. However, the production method of the present invention is not limited to this.

  When a press cake is used as the pigment, the press cake and varnish are sufficiently mixed, and then water derived from the press cake may be removed from the mixture. In order to mix the press cake and the varnish, a kneader or a high-speed stirring device can be used. In order to remove moisture from the mixture, the mixture may be stored in a sealed container and heated in a reduced pressure state. When the moisture contained in the press cake is separated when mixing using a kneader or a high-speed stirring device, it may be drained by slanting prior to removing the moisture under reduced pressure. The above-mentioned mixture from which water has been removed is a pigment dispersion composition that is an object of this step, and this may be used in the next step as it is or after further pigment dispersion by a kneading apparatus such as a three-roll mill. It may be used in the next step.

  When using a powdery pigment as the pigment, the pigment and varnish are sufficiently mixed, and the resulting mixture is kneaded to disperse the pigment. To mix the pigment and the varnish, a high-speed stirring device can be used. In order to knead the obtained mixture, a kneading apparatus such as a three-roll mill or a bead mill can be used. A pigment dispersion composition that is an object of this step is obtained by appropriately examining the degree of pigment dispersion using a grind gauge and kneading until a desired pigment dispersion is obtained.

[Gelling process]
The pigment dispersion composition that has undergone the mixing step is subjected to a gelation step. The gelation step is a step of adding a bivalent or higher metal alkoxy compound to the pigment dispersion composition and setting the temperature to 70 to 200 ° C. in that state. Through this step, the resin contained in the pigment dispersion composition is cross-linked to the metal alkoxy compound, and the entire pigment dispersion composition is gelled.

  As already described, in the conventional method for producing an ink composition, an ink composition was prepared by mixing a gelled varnish and a pigment. However, in the method for producing an ink composition of the present invention, the varnish and After the pigment dispersion composition is prepared by mixing with the pigment, the entire pigment dispersion composition is gelled. As described above, the “sagging” phenomenon is remarkably improved by preparing the ink composition by such a procedure. The reason why such an effect is obtained is not necessarily clear, but compared to the conventional method in which only the varnish is gelled and used, the pigment dispersion composition that is one step before the ink composition is gelled. Thus, a cross-linked network structure can be formed throughout the ink composition, the oil component is retained in this network structure, and a sudden increase in viscosity accompanying the release of the oil component, that is, a “slipping” phenomenon. Presumed to be suppressed. As described above, the varnish used for preparing the pigment dispersion composition may be a dissolved varnish alone, a gelled varnish alone, or a dissolved varnish and a gelled varnish. It may be a combination. As described above, it is preferable to use a gelled varnish as at least a part of the varnish for preparing the pigment dispersion composition because the “slipping” phenomenon tends to be further suppressed after the ink composition is formed. Street.

  The bivalent or higher-valent metal alkoxy compound added to the pigment dispersion composition in this step reacts with a polar group such as a carboxyl group or a hydroxyl group contained in the resin molecule to release an alcohol between the metal-resin molecule. A bond is formed. Since this alkoxy compound is divalent or higher, crosslinking is performed between a plurality of resin molecules, and the apparent molecular weight of the resin molecules contained in the composition is increased to gel the composition.

  As the bivalent or higher metal alkoxy compound, those containing aluminum as a metal are preferably used, and among them, diisopropoxy aluminum ethyl acetoacetate represented by the following chemical formula is preferably exemplified. This compound is commercially available, for example, a product sold under the trade name ALCH from Kawaken Fine Chemical Co., Ltd. can be easily obtained.

  The amount of addition of the bivalent or higher metal alkoxy compound to the pigment dispersion composition is preferably 0.1 to 3.0 parts by mass of the metal alkoxy compound with respect to 100 parts by mass of the pigment dispersion composition. More preferably 0.5 to 2.0 parts by mass, and even more preferably 0.8 to 1.5 parts by mass.

  After adding a bivalent or higher metal alkoxy compound to the pigment dispersion composition, the temperature is raised to 70 to 200 ° C., and the temperature is maintained for about 30 to 120 minutes. Thereby, a pigment dispersion composition is gelatinized. As temperature, 100-150 degreeC is mentioned preferably.

  The pigment dispersion composition after gelation is allowed to cool, and the viscosity is adjusted until the composition has a desired viscosity by adding the oil component. The viscosity may be appropriately set in consideration of the printing machine to which the ink composition is applied, handling properties, etc., but if it is a osmotic dry offset ink composition for newspaper printing, it can be measured at 25 ° C. using a Raleigh viscometer. Although it can illustrate that a value is 2.0-20 Pa * s, it is not specifically limited.

  The gelled pigment dispersion composition becomes an ink composition through the viscosity adjustment as described above. In the ink composition thus prepared, the “slipping” phenomenon is remarkably suppressed, so that good printability is maintained even when printing is continued for a long time.

  The present invention will be described more specifically with reference to the following examples. However, the present invention is not limited to these examples. In the following description, “%” means “mass%” and “part” means mass parts unless otherwise specified.

[Preparation of varnish A for ink composition (non-gelling varnish)]
In a four-necked flask equipped with a condenser, thermometer and stirrer, 35 parts of rosin-modified phenolic resin (manufactured by Arakawa Chemical Co., Ltd.) with a weight average molecular weight of 100,000, 20 parts of soybean oil and AF Solvent No. 6 (JX Nikko) (Nisseki Energy Co., Ltd.) 44.5 parts charged, the temperature was raised to 200 ° C., and the resin was dissolved by maintaining the same temperature for 1 hour, whereby the varnish A for an ink composition which is a non-gelling varnish (Hereinafter referred to as Varnish A).

[Preparation of ink composition varnish B (gelled varnish)]
In a four-necked flask equipped with a condenser, thermometer and stirrer, 35 parts of rosin-modified phenolic resin (manufactured by Arakawa Chemical Co., Ltd.) with a weight average molecular weight of 100,000, 20 parts of soybean oil and AF Solvent No. 6 (JX Nikko) After charging 44.5 parts (manufactured by Nisseki Energy Co., Ltd.), the temperature was raised to 200 ° C. and the resin was dissolved by maintaining the same temperature for 1 hour, and then diisopropoxyaluminum ethyl acetoacetate (Kawaken Fine Chemical Co., Ltd.) 0.5 parts of company-made ALCH) was added, and then heated and held at 170 ° C. for 60 minutes to obtain a varnish B for ink composition (hereinafter referred to as “varnish B”) which is a gelled varnish.

[Preparation of magenta ink base A]
In a flasher, 35 parts of the above varnish A and 30 parts of pigment press cake of brilliant carmine 6B (pigment pure content 25%) as a pigment dry solid content are added and kneaded at a temperature of 50 ° C. The water contained in the cake was separated from the solid content in the flasher (flushing), and this was drained by decantation. Thereafter, the solids present in the flasher are heated to 110 ° C. under reduced pressure to remove moisture from the solids, and 20 parts of the varnish A and 15 parts of soybean oil are added thereto and mixed. To obtain a magenta ink base A (hereinafter referred to as M base A). M Base A is an ink base prepared using only non-gelled varnish.

[Preparation of magenta ink base B]
In a flasher, 35 parts of the above varnish B and 30 parts of pigment press cake of brilliant carmine 6B (pigment pure content 25%) as a pigment dry solid content are added and kneaded at a temperature of 50 ° C. The water contained in the cake was separated from the solid content in the flasher (flushing), and this was drained by decantation. Thereafter, the solids present in the flasher are heated to 110 ° C. under reduced pressure to remove moisture from the solids, and 20 parts of the varnish B and 15 parts of soybean oil are added thereto and mixed. To obtain a magenta ink base B (hereinafter referred to as M base B). M base B is an ink base prepared using only gelled varnish.

[Preparation of Cyan Ink Base A]
After mixing 30 parts of cyanine blue pigment, 60 parts of varnish A and 10 parts of soybean oil, this was kneaded by a three-roll mill, and cyan ink base A (hereinafter referred to as “C base A”). Obtained. C Base A is an ink base prepared using only non-gelled varnish.

[Preparation of cyan ink base B]
After mixing 30 parts of cyanine blue pigment, 60 parts of the above varnish B, and 10 parts of soybean oil, this was kneaded with a three-roll mill to prepare cyan ink base B (hereinafter referred to as “C base B”). Obtained. C base B is an ink base prepared using only gelled varnish.

[Preparation of base ink]
After mixing 50 parts of calcium carbonate, 40 parts of the varnish A and 10 parts of soybean oil, this was kneaded by a three-roll mill to obtain a constitutional ink base (hereinafter referred to as “constitutional base”).

[Preparation of ink compositions of Examples 1 to 12]
The above ink base, constitution base, and soybean oil (that is, each component excluding ALCH) were mixed at a blending ratio shown in Tables 1 and 2 to obtain a pigment dispersion composition. Then, after adding diisopropoxy aluminum ethyl acetoacetate (manufactured by Kawaken Fine Chemical Co., Ltd., ALCH) at the blending ratio shown in Tables 1 and 2 for each pigment dispersion composition, the temperature was raised to 120 ° C. with stirring. The ink compositions of Examples 1 to 12 were prepared by maintaining the temperature for 1 hour and then allowing to cool, and adjusting the viscosity by adding soybean oil so that the viscosity was 6.0 ± 0.5 Pa · s. Obtained. In addition, the mixture ratio shown to Table 1 and 2 is a mass part.

[Preparation of ink compositions of Comparative Examples 1 and 2]
Mix each of the above-mentioned color base ink, constitution base, machine oil and soybean oil in the blending ratio shown in Table 2 and add soybean oil to adjust the viscosity so that the viscosity becomes 6.0 ± 0.5 Pa · s. Thus, ink compositions of Comparative Examples 1 and 2 were obtained. In addition, the mixture ratio shown in Table 2 is a mass part.

[Print Evaluation]
For each of the ink compositions of Examples 1 to 12 and Comparative Examples 1 and 2, using an N-750 printing experimental machine (manufactured by Higashihama Seiki Co., Ltd.), the paper was used for newspapers at a printing speed of 120,000 copies / hour A printing test was carried out at the following solid paper surface density as the renewal paper. 20,000 copies are printed for each ink composition, and the “slipping” state of the ink composition on the swim roller (the roller that supplies dampening water to the printing plate) after each printing is finished evaluated. The evaluation results are shown in Tables 1 and 2. As dampening water in the printing test, tap water added with 0.7% SAH-7 (manufactured by Sakata Inx Co., Ltd., alkaline H solution) is used, and spray dampener SSD-12 ( Sakata Inx Co., Ltd.) was used. At the time of printing, in order to compare the printing state in the vicinity of the lower limit of the water width, the SSD-12 dial was raised by two points from the lower limit value of the water width. The solid paper surface density of each color was 0.95 ± 0.02 for both magenta and cyan. The solid paper surface density is a numerical value obtained by measuring the density of a solid part in a printed material with a Spectroeye densitometer (manufactured by Gretagmacbeth). The evaluation criteria are as follows.
A: The ink composition on the roller adhered to the finger, and its viscosity was the same as the original ink composition
○: The ink composition on the roller adhered to the finger, but the viscosity was slightly increased compared to the original ink composition. Δ: The ink composition on the roller adhered to the finger, but the amount was slightly ×: The ink composition on the roller does not adhere to the finger

[Evaluation over time]
For each of the ink compositions of Examples 1 to 12 and Comparative Examples 1 and 2, using a vertical glass plate flow meter immediately after the preparation, and after being prepared and allowed to stand for 30 days in a 60 ° C. heat insulation box, At 25 ° C., the distance that 0.5 cc of the printing ink composition flowed by gravity for 10 minutes was measured. Then, by dividing the flow distance of what was left for 30 days by the flow distance of that immediately after preparation, the change rate of fluidity with time was calculated, and the change with time was evaluated. The results are shown in Tables 1 and 2. The evaluation criteria are as follows.
◎: Change rate of fluidity was less than 110% ○: Change rate of fluidity was 110% or more and less than 150% △: Change rate of fluidity was 150% or more

  As shown in Tables 1 and 2, in the ink compositions of Examples 1 to 12 in which the varnish and the pigment were mixed and dispersed to form a pigment dispersion composition and then gelled to form an ink composition, the gel was formed against the varnish. Compared with the ink compositions of Comparative Examples 1 and 2 which were used as ink compositions after conversion, the “Nappa” phenomenon tended to be improved. In addition, when the gel composition is gelled, if the amount of the metal alkoxy compound added is 0.5 to 2 parts by mass, the change in the ink composition with time is also suppressed, and it is confirmed that a more preferable result is obtained. It was done. Moreover, although the printing evaluation was all good in the ink compositions of Examples 1, 11 and 12, the ink compositions of Examples 11 and 12 were better in the finger touch in the printing evaluation, and at least partly It was confirmed that the “slipping” phenomenon tends to be suppressed by preparing an ink composition obtained by preparing a pigment dispersion composition using gel varnish and gelling it.

Claims (5)

A mixing step of preparing a pigment dispersion composition comprising a pigment, a resin and an oil component;
A gelling step to 70 to 200 ° C. The temperature of the pigment dispersion composition in a state of being added alkoxy compounds of divalent or higher valent metal, only contains, at least a portion of the resin and the oil component, 2 A method for producing an ink composition for osmotic drying offset printing, which is subjected to the mixing step in the state of being heated and mixed in the presence of a metal alkoxy compound having a valence higher than that to form a gelled varnish .   2. The production of an ink composition for osmotic drying offset printing according to claim 1, wherein the addition amount of the metal alkoxy compound is 0.1 to 3.0 parts by mass with respect to 100 parts by mass of the pigment dispersion composition. Method.   The method for producing an ink composition for osmotic drying offset printing according to claim 1 or 2, wherein the metal alkoxy compound is a compound containing aluminum as a metal. The method for producing an ink composition for osmotic drying offset printing according to any one of claims 1 to 3, wherein the metal alkoxy compound is diisopropoxy aluminum ethyl acetoacetate represented by the following chemical formula.

  The said resin and the said oil component are provided to the said mixing process in the state which was heated and mixed in presence of the bivalent or more metal alkoxy compound, and became the gelatinization varnish. The manufacturing method of the ink composition for osmosis | dry_drying type | mold offset printing of any one.