JP5108430B2 - Ink composition - Google Patents

Description

  The present invention relates to an offset ink composition having a osmotic drying function, and more specifically, an offset having a osmotic drying function capable of providing a printed matter having a high coating film curing speed and excellent coating film gloss and print image reproducibility. The present invention relates to an ink composition (hereinafter sometimes simply referred to as an ink composition).

  Conventionally, offset inks having a penetrating drying function are mainly used for sheet-fed offset printing, and the drying proceeds through two steps of penetrating drying and oxidative polymerization drying. Among the above processes, when the osmotic drying, which is the initial stage of the coating film curing, is slow, there is a problem that ink adhesion stains occur between the printed products that are stacked one after another immediately after printing.

  The above-mentioned osmotic drying function means that when the ink is printed on an absorbent support such as paper, the solvent is a low-viscosity component in the ink immediately after the ink is transferred to the paper. As a result, the coating film is cured. If the above low viscosity component is difficult to penetrate and separate from the ink component, the coating will cure slowly, and the sticky adhesive ink coating will be on the back side of the printed paper or on the ink coating surface. The problem of ink adhesion stains that adhere to the ink occurs.

  As a method of avoiding the above ink adhesion stains, a method of spraying corn starch or other spray powder on an ink film that is insufficiently cured and providing a gap between the printed materials to avoid contact with the ink film as much as possible There is. However, the spraying of these spray powders deteriorates the quality of printed matter or deteriorates the printing work environment, and reducing the spraying amount of spray powder as much as possible has been a major issue.

  In general, in order to improve the above-mentioned penetration drying, it is necessary to weaken the solubility between components such as varnish resin, solvent and vegetable oil used in ink, and to quickly permeate and remove the solvent from the ink system. For this reason, conventionally, a formulation that uses a resin with low solubility or uses a varnish with reduced vegetable oil as an ink to accelerate the osmotic drying property has been used.

  However, resins that are more effective for osmotic drying are less likely to exist in a state where they are uniformly dissolved in the varnish, and in the above conventional formulations, appropriate ink physical properties can be stably obtained due to the effects of resin precipitation and undissolved components. Absent. These inks tend to increase in viscosity, leading to a decrease in reproducibility of printed images due to poor ink transfer, paper peeling, and particularly a decrease in gloss, so extremely low-solubility resins cannot be used. Improvement in osmotic drying could not be expected.

  A certain printing ink composition (Patent Document 1) is disclosed as an offset ink having the above-described penetration drying function. However, the ink disclosed in Patent Document 1 is obtained by replacing a part or all of a petroleum solvent with a fatty acid ester having a high dissolving power. However, it is difficult to separate from the ink system, and as an ink having a penetrating and drying function, the coating film curability cannot be improved more than the conventional ink.

  In view of the above, there is a demand for an ink composition that can provide a printed material having a high coating film curing rate and excellent coating film gloss and printed image reproducibility.

JP 2005-1113070 A

  Accordingly, an object of the present invention is to provide an ink composition having greatly improved coating film curability without impairing printability and print quality.

The above object is achieved by the present invention described below. That is, the present invention provides a varnish prepared by dispersing dissolving the varnish resin and a dissolution aid in an organic solvent and also contains at least, the varnish resin is a rosin-modified phenolic resin and / or rosin ester resin, before Symbol The solubilizer is a triester of at least one fatty acid selected from caproic acid, caprylic acid, and capric acid and glycerin, the organic solvent is a petroleum solvent, and the solubilizer is added to all varnishes. An offset ink composition characterized by containing an amount of 0.1% by mass to less than 50% by mass.

  As a result of intensive studies to solve the above-mentioned problems, the present inventor can easily dissolve a low-solubility resin that is difficult to dissolve in a solvent of a conventional varnish, containing the specific dissolution aid. By using the varnish, the low-viscosity component in the ink coating immediately after printing, particularly a petroleum-based solvent, due to the characteristics of the above-mentioned low-melting resin without impairing the on-machine stability of the ink and the gloss of the coating. It has been found that an ink composition having excellent penetration and drying properties can be obtained. Furthermore, by using a polymer resin having a low solubility and a high weight average molecular weight, in addition to the above-mentioned penetration drying property, the polymerization inside the ink coating film is further promoted, and the conventional ink coating is promoted. An ink composition having extremely excellent coating film curing performance as compared with the film can be obtained.

  According to the present invention, there is provided an ink composition capable of obtaining a printed material having a high coating film curing rate and excellent in coating film gloss and print image reproducibility.

  Next, the present invention will be described in more detail with reference to the best mode for carrying out the invention. As the varnish resin used in the varnish constituting the ink composition of the present invention, any varnish resin can be used as long as it is used in offset ink having a conventional osmotic drying function. Examples of the varnish resin include rosin ester resins, rosin-modified phenol resins, maleic acid-modified rosin ester resins, alkyd resins, rosin-modified alkyd resins, gilsonite resins, petroleum resins, hydrocarbon resins, acid-modified hydrocarbon resins, etc. Is mentioned.

  Of the above varnish resins, rosin-modified phenolic resins and / or rosin ester resins are preferably used. The above rosin-modified phenolic resin and rosin ester resin can be used alone or in combination as appropriate.

  The rosin-modified phenolic resin and rosin ester resin have a cloud point of 50 ° C. to less than 200 ° C. and / or a weight average molecular weight of 80,000 to 500,000, preferably a cloud point of 100 ° C. to 180 ° C. and / or Those having a weight average molecular weight of 80,000 to 300,000 are particularly effective. When the cloud point and weight average molecular weight of the above rosin-modified phenolic resin and rosin ester resin are within the above ranges, low viscosity components in the ink coating immediately after printing, especially petroleum-based solvents, penetrate into the printing paper from the ink. It is easy to detach, promotes the solidification of the above-mentioned resin dissolved in the coating film, and the printed material has excellent ink coating film curing performance compared to the offset ink having a osmotic drying function using a conventional varnish resin. can get. On the other hand, when the cloud point and the weight average molecular weight are out of the above ranges, the penetration drying property of the low viscosity component in the ink coating film is lowered, or the gloss and printed image reproducibility of the printed matter are lowered.

  In addition, the cloud point in this invention is a resin for varnish, for example, rosin modified phenol resin or rosin ester resin (x), and Nippon Oil Co., Ltd. AF solvent 6 (y) which is a petroleum solvent. It is a cloud point value measured by a temperature lowering operation after blending at a ratio of x / y = 1/4 (mass ratio) and heating and dissolving until the resin is dissolved. The above cloud point represents the solubility of the resin, and the higher the cloud point, the less the resin is judged to be. Moreover, a weight average molecular weight is the value converted into standard polystyrene measured by GPC.

  Examples of the rosin-modified phenol resin include a resole resin, a reaction product of rosin and / or rosin and an unsaturated carboxylic acid, a reaction product of a polyhydric alcohol, and the like. The rosin modified phenolic resin preferably has a cloud point and / or a weight average molecular weight within the above range. The above-mentioned resol resin is a condensation product of p-alkylphenols such as cresol, p-tertiary butylphenol, p-secondary butylphenol, p-octylphenol, and other phenols such as bisphenol A and formaldehyde.

  Examples of the rosin to be reacted with the above resole resin include various rosins such as gum rosin, wood rosin, tall oil rosin, polymerized rosin, and disproportionated rosin. Examples of the unsaturated carboxylic acid that forms an addition product with the rosin include, for example, maleic acid, itaconic acid, citraconic acid and the like, and anhydrides thereof, fumaric acid, dimer acid, trimer acid, and acrylic acid. And methacrylic acid.

  Examples of the polyhydric alcohol include ethylene glycol, propylene glycol, trimethylene glycol, 1,4-butanediol, 1,6-hexanediol, glycerin, pentaerythritol, dipentaerythritol, trimethylolpropane, diethylene Examples include divalent or higher alcohols such as glycerin.

  In addition, as the rosin ester resin, for example, an addition reaction product of an unsaturated polybasic acid and / or an unsaturated monocarboxylic acid is added to a rosin or a mixture of a rosin and another diene compound. A rosin ester resin obtained by esterifying a diol with a polyol, and other known rosin ester resins. As the rosin ester resin, those having a cloud point and / or a weight average molecular weight within the above range are preferably used. As these rosin ester resins, those produced by a known general synthetic method can be used, and rosins, diene compounds, unsaturated polybasic acids, unsaturated compounds used in the synthesis of the above rosin ester resins. Monocarboxylic acids and polyols are conventionally known and have no problem.

  As a specific example of the rosin ester resin, for example, a mixture of wood rosin and 1,3-pentadiene resin is heated to 200 ° C. to dissolve uniformly, and then acrylic acid and maleic anhydride are added to synthesize diene. And a rosin ester resin having a weight average molecular weight of 80,000 to 500,000 obtained by esterification of the reaction product at 270 to 280 ° C. with pentaerythritol.

  Examples of rosins used in the synthesis of the rosin ester resin include natural rosins such as wood rosin, gum rosin, tall oil rosin, polymerized rosin obtained by polymerizing rosin under a catalyst, hydrogenated rosin, and the like. Of the mixture.

  Examples of the diene compound used by mixing with the above rosins include diolefin compounds such as 1,3-pentadiene petroleum resin and 1,4-pentadiene petroleum resin, and mixtures thereof.

  In addition, as unsaturated polybasic acid and unsaturated monocarboxylic acid, suitable for diene compound and Diels-Alder reaction (diene synthesis), for example, acrylic acid, methacrylic acid, crotonic acid, isocrotonic acid, angelic acid, tiglic acid , Α-ethylcrotonic acid, maleic acid, fumaric acid, citraconic acid, mesaconic acid, itaconic acid, maleic anhydride, itaconic anhydride and the like.

  As the polyol, low molecular polyols such as ethylene glycol, diethylene glycol, dipropylene glycol, 1,4-butanediol, 1,6-hexanediol, trimethylolpropane, pentaerythritol, polyols such as polyethylene glycol and polypropylene glycol, Other polyol compounds such as polyester polyols and polyether polyols may be mentioned.

  The dissolution aid characterizing the present invention is difficult to dissolve in the varnish formulation using the conventional vegetable oil or solvent when preparing the varnish using the resin for varnish, particularly the weight average molecular weight is relatively low. It has the effect of accelerating the dissolution of the above-mentioned varnish resin into the varnish, and further impregnated and dried the varnish resin without impairing the on-machine stability of the resulting ink and the gloss of the ink coating (printed matter). A performance improving effect is imparted to the ink composition. The effect of the dissolution aid is particularly useful for varnish resins having a cloud point of 50 ° C. or higher and lower than 200 ° C. and / or a weight average molecular weight of 80,000 to 500,000.

  Said solubilizing agent is a polyhydric alcohol fatty acid ester other than vegetable oil, and the solubilizing agent occupies 0.1% by mass to less than 50% by mass, preferably 1% by mass to 40% by mass in all varnishes. Contains. When the content of the dissolution aid is within the above range, the effect as the dissolution aid is sufficiently exhibited. When there are too many compounding ratios in the varnish of said dissolution aid, the osmotic drying property of the ink composition obtained will fall. On the other hand, when the mixing ratio of the dissolution aid is too small, a sufficient effect as the dissolution aid cannot be obtained. The above-mentioned solubilizing agent is a polymer as compared with conventional fatty acid monoesters, but has a very low aniline point, so that it has a viscosity and boiling point close to those of vegetable oils that are usually used, but has excellent solubility in resins.

  The above polyhydric alcohol fatty acid ester can be obtained by a known synthesis method, for example, a method by direct esterification reaction by the reaction of the above fatty acid and polyhydric alcohol, or other ester and polyhydric alcohol or ester and fatty acid, or ester. Examples include a method based on an ester exchange reaction synthesized from an ester, a method based on a reaction between acyl chloride and a polyhydric alcohol, a method based on a reaction between an epoxide and a fatty acid, and a method based on a direct esterification reaction is preferable. The above-mentioned direct esterification reaction method involves distilling water by mixing the fatty acid, polyhydric alcohol and fatty acid and adding an appropriate amount of an azeotropic dehydrating agent such as toluene or xylene and heating. Let the reaction proceed. As the catalyst, Bronsted acid such as sulfuric acid and p-toluenesulfonic acid, Lewis acid such as zinc oxide, activated alumina, titanium oxide, and tetraisopropyl titanate are used.

  Examples of the polyhydric alcohol constituting the dissolution aid include ethylene glycol, propylene glycol, neopentyl glycol, 3-methyl-1,5-pentanediol, 1,4-cyclohexanedimethanol, and 1,7-heptane. Dihydric alcohols such as diol, diethylene glycol, and triethylene glycol; Trihydric alcohols such as glycerin, trimethylolpropane, and trimethylolethane; Tetravalent alcohols such as diglycerin, erythritol, pentaerythritol, and sorbitan; Xylitol, triethylene Examples include pentavalent alcohols such as glycerin; and other hexavalent alcohols such as sorbitol and tetraglycerin.

  Examples of the fatty acid that reacts with the polyhydric alcohol to form the polyhydric alcohol fatty acid ester include formic acid, acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, enanthic acid, caprylic acid, pelargonic acid, and caprin. Saturated fatty acids such as acid, undecyl acid, lauric acid, tridecylic acid, pentadecylic acid, palmitic acid, heptadecylic acid, stearic acid, nonadecanoic acid, arachidic acid, acrylic acid, crotonic acid, isocrotonic acid, undecylenic acid, sorbic acid, oleic acid And unsaturated fatty acids such as elaidic acid, linoleic acid, linosinic acid and ricinoleic acid.

The dissolution aid is preferably at least one selected from compounds represented by the following general formula (1). The following compounds are particularly excellent in dissolving ability for the varnish resin. The following compounds can be used alone or in combination of two or more.
R ₁ (OCOR ₂ ) _n (1)
(In the general formula (1), R ₁ represents a polyhydric alcohol residue having 3 carbon atoms, and R ₂ represents an alkyl group or alkenyl group having 5 to 15 carbon atoms. Represents an integer of 2 to 3.)

The compound represented by the general formula (1) is a polyhydric alcohol fatty acid ester of a polyhydric alcohol having 3 carbon atoms and a fatty acid having an alkyl group or alkenyl group having 5 to 15 carbon atoms. Examples of the alcohol having a residue of a polyhydric alcohol having 3 carbon atoms which is R ₁ constituting the above compound include propylene glycol and glycerin, preferably glycerin.

  Examples of the fatty acid having an alkyl group or alkenyl group having 5 to 15 carbon atoms constituting the compound of the general formula (1) include, for example, caproic acid, enanthic acid, caprylic acid, pelargonic acid, capric acid, undecyl. Saturated fatty acids such as acid, lauric acid, tridecylic acid, myristic acid, pentadecylic acid and palmitic acid, and unsaturated fatty acids such as undecylenic acid and sorbic acid, particularly preferably caproic acid, caprylic acid and capric acid.

  As said polyhydric alcohol fatty acid ester, propylene glycol fatty acid ester, glycerol fatty acid ester, etc., Preferably glycerol fatty acid ester is mentioned, for example. Examples of the glycerin fatty acid ester include caproic acid, enanthic acid, caprylic acid, pelargonic acid, capric acid, undecylic acid, lauric acid, tridecylic acid, myristic acid, pentadecylic acid, and palmitic acid, undecylenic acid, Examples include triesters of fatty acids having 5 to 15 carbon atoms such as sorbic acid and glycerin, preferably triesters of at least one fatty acid selected from caproic acid, caprylic acid and capric acid and glycerin.

  Especially as said glycerin fatty acid ester, Preferably a tri (capryl capric acid) glyceride and / or a tricaproic acid glyceride are mentioned. The tri (caprylic / capric) acid glyceride is a triester of glycerin and a 3: 1 (mass ratio) mixture of caprylic acid and capric acid. The above glycerin fatty acid ester is a polymer and has a high boiling point while maintaining high solubility, so that a uniform varnish system can be obtained while using the hardly soluble resin for varnish, and the resulting ink composition Has an appropriate viscosity and does not impair the gloss of the coating film or the on-machine stability.

  The organic solvent used in the present invention may be any known organic solvent that is used to disperse and dissolve the varnish resin and the dissolution aid, and is used in conventional osmotic drying offset inks. Preferably, a petroleum solvent is mentioned. Examples of the petroleum solvent include paraffinic hydrocarbons, naphthenic hydrocarbons obtained from petroleum fractions, and hydrocarbon solvents composed of hydrocarbons having an aromatic content of 1% or less. These may be used alone or in combination of two or more. The above petroleum-based solvents are from Nippon Oil Corporation “O Solvent (H)”, “AF Solvent No. 4”, “AF Solvent No. 5”, “AF Solvent No. 6”, “AF Solvent No. 7” And can be used in the present invention.

  The varnish used in the ink composition of the present invention is prepared by blending the varnish resin, the dissolution aid and the organic solvent, preferably a vegetable oil and, if necessary, a gelling agent. As a method for preparing the varnish, for example, the resin for varnish, a dissolution aid, an organic solvent and a vegetable oil are appropriately blended, and the mixture is uniformly heated and stirred at 200 ° C. for 30 minutes in a nitrogen stream. Then, it is cooled to 150 ° C., mixed with a gelling agent, and further prepared by heating and stirring uniformly at 200 ° C. for 60 minutes.

  As said vegetable oil, well-known non-drying oil, semi-drying oil, drying oil, etc. can be used. As the above-mentioned non-drying oil, for example, castor oil, peanut oil, olive oil and the like, and as the semi-drying oil, for example, soybean oil, cottonseed oil, rapeseed oil, sesame oil, corn oil and the like, and as the dry oil, for example, , Linseed oil, eno oil, tung oil, etc., preferably soybean oil and linseed oil.

  Examples of the gelling agent include ethyl acetoacetate aluminum diisopropoxide, aluminum ethyl acetate diisopropylate, aluminum tris (ethyl acetate), aluminum stearate, aluminum octylate, aluminum isopropylate, aluminum diisopropylate. Poxysite and the like, preferably ethyl acetoacetate aluminum diisopropoxide, can be mentioned, and can be obtained from Kawaken Fine Chemical Co., Ltd. under the trade name ALCH-50 and used in the present invention.

  The ink composition of the present invention may be an overprint varnish type in which no colorant is blended in the varnish, but may be a type in which a colorant is dissolved or dispersed in the varnish by a known method. Further, if necessary, additives such as an oxidation polymerization catalyst (dryer), a surfactant, a wax compound, and a skin anti-skinning agent may be added within a range that does not interfere with the object of the present invention.

  The ink composition of the present invention preferably has a cloud point of 100 ° C. to 180 ° C. and a weight average molecular weight of 80,000 to 300,000, a rosin-modified phenol resin and / or a rosin ester resin, caproic acid, It is effective to contain at least a varnish containing in a petroleum solvent at least one fatty acid selected from caprylic acid and capric acid and a triester of glycerin.

  An organic carboxylic acid metal salt can be used as the oxidative polymerization catalyst. Examples of the organic carboxylic acid metal salt include metals such as cobalt, manganese, zinc, calcium and zirconium of organic carboxylic acids such as octylic acid, propionic acid, isopentanoic acid, naphthenic acid, palmitic acid, stearic acid and oleic acid. A salt, preferably cobalt octylate, can be mentioned, and can be obtained from Nippon Chemical Industry Co., Ltd. under the trade name “Cobalt dryer 8%” and used in the present invention.

  Examples of the wax compound include waxes such as paraffin wax, carnauba wax, polyethylene wax, and polytetrafluoroethylene wax. Examples of the anti-skinning agent include cresol, o-isopropylphenol, and t-butylhydroxytoluene. Phenols, and oximes such as methyl ethyl ketone oxime.

  Examples of the colorant include inorganic pigments such as titanium oxide, calcium carbonate, barium sulfate, zinc white, petal, ultramarine, iron oxide, and aluminum powder, insoluble azo pigments, azo pigments laked with metal salts, and condensation. Azo pigment, phthalocyanine pigment, anthraquinone pigment, chelate pigment, quinacridone pigment, thioindigo pigment, isoindolinone pigment, dioxazine pigment, quinophthalone pigment, perylene pigment, perinone pigment, indigo pigment, pyranthrone Organic pigments such as pigments, anthanthrone pigments, flavanthrone pigments, diketopyrrolopyrrole pigments, isoindoline pigments, benzimidazolone pigments, anthraquinone pigments, carbon black, and other dyes.

  Next, preparation examples of varnishes J1 to J5 used in examples of the present invention and preparation examples of varnishes K1 to K4 used in comparative examples, and examples and comparative examples of ink compositions using these varnishes are given. The present invention will be described more specifically. “Part” or “%” in the text is based on mass unless otherwise specified. In addition, this invention is not limited to the following Example.

(Varnishes J1-J5 and Varnishes K1-K4)
As shown in Table 1, varnish resin A or varnish resin B, dissolution aid C or fatty acid ester D, organic solvent E, and vegetable oil F, which are each component constituting the varnish, Heat and stir uniformly at 200 ° C. for 30 minutes under a nitrogen stream, then cool to 150 ° C., mix with gelling agent G, and further heat and stir uniformly at 200 ° C. for 60 minutes to make varnishes J1 to J5. And varnishes K1-K4 were prepared.

The varnish resin A or B, the dissolution aid C or the fatty acid ester D, the organic solvent E, the vegetable oil F, and the gelling agent G in Table 1 are as follows.
-Resin A for varnish: rosin modified phenolic resin (A1, A2, A3)
(Rosin-modified phenolic resin A1)
As the varnish resin, the following production examples are used. A reactor equipped with a stirrer, reflux condenser and thermometer was charged with 47 parts of toluene, 320 parts of p-octylphenol, and 101 parts of 92% paraformaldehyde, heated to 60 ° C. and dissolved, and then 8 parts of sodium hydroxide. . Next, the reaction was performed by heating to 90 ° C., and then water was separated and removed to obtain a resole resin having an average number of nuclei of 3. Next, in a reactor equipped with a stirrer, a reflux condenser with a water separator, and a thermometer, 600 parts of gum rosin was dissolved in a nitrogen atmosphere, the above-mentioned resole resin was added, and then the temperature was slowly raised to 200 At 56 ° C., 56 parts of glycerin and 0.6 parts of magnesium oxide as a catalyst were added and heated to 260 ° C. in 7 hours for esterification to prepare a rosin-modified phenolic resin A1 having a weight average molecular weight of 100,000 and a cloud point of 120 ° C. did.

(Rosin modified phenolic resin A2)
After preparing a resole resin having an average number of nuclei of 3 in the same manner as rosin-modified phenol resin A1, 600 parts of gum rosin are dissolved in a nitrogen atmosphere using the above reaction apparatus, and the above-mentioned resole resin is added. Thereafter, the temperature was raised slowly, and 9 parts of maleic anhydride was added at 180 ° C., 62 parts of glycerin and 0.6 parts of magnesium oxide were added as a catalyst, and the temperature was raised to 260 ° C. in 7 hours to esterify, A rosin-modified phenol resin A2 having an average molecular weight of 180,000 and a cloud point of 150 ° C. was prepared.

(Rosin-modified phenolic resin A3)
After preparing a resole resin having an average number of nuclei of 2, 600 parts of gum rosin is dissolved in a nitrogen atmosphere using the above reaction apparatus, and the above-mentioned resole resin is added. Thereafter, the temperature was raised slowly, and 9 parts of maleic anhydride was added at 180 ° C., 62 parts of glycerin and 0.6 parts of magnesium oxide were added as a catalyst, and the temperature was raised to 260 ° C. in 7 hours to esterify, A rosin-modified phenol resin A3 having an average molecular weight of 50,000 and a cloud point of 45 ° C. was prepared.

-Resin B for varnish: Rosin ester resin 800 g of rosin and 200 g of 1,3-pentadiene petroleum resin were added to a reactor equipped with a stirrer and a thermometer, heated to 200 ° C., and 50 g of acrylic acid and maleic anhydride. The diene was synthesized by adding 50 g of acid. To the reaction product, 130 g of pentaerythritol and 0.5 g of magnesium oxide as a catalyst were added and an esterification reaction was carried out at 280 ° C. to prepare a rosin ester resin having a weight average molecular weight of 100,000 and a cloud point of 130 ° C.

・ Solubility aid C (C1, C2)
C1: Tricaproic acid glyceride C2: Tri (caprylic / capric) glyceride The dissolution aid C2 is a triester of glycerin and a 3: 1 (mass ratio) mixture of caprylic acid and capric acid.

Fatty acid ester D: Octyl acid 2-ethylhexyl ester Organic solvent E: AF solvent No. 6 Vegetable oil F: Soybean oil Gelling agent G: ALCH-50 manufactured by Kawaken Fine Chemicals Co., Ltd.

表１中の数値は、ワニス中の溶解助剤の含有量以外は配合部数を表わす。

The numerical values in Table 1 represent the number of parts other than the content of the dissolution aid in the varnish.

[Examples 1 to 5 and Comparative Examples 1 to 4]
Using the varnishes J1 to J5 and varnishes K1 to K4, as shown in Table 2, phthalocyanine blue, cobalt dryer 8%, and AF solvent No. 6 were blended into the varnish and kneaded uniformly by a known method. Ink compositions L1 to L5 of the present invention and ink compositions M1 to M4 of comparative examples were prepared. In addition, the ink composition M1 is an ink composition having a permeation drying function of a standard composition conventionally used.

表２中の数値は、配合部数を表わす。

The numerical values in Table 2 represent the number of blended parts.

About each ink composition obtained above, it evaluated by the following evaluation method regarding the coating-film curability of an ink, coating-film glossiness, printed image reproducibility, and ink adhesion stain resistance. The evaluation results are shown in Table 3.
(Coating film curability)
Using 0.1 ml of each of the ink compositions obtained above, the color is developed on art paper by using a RI tester 4-split roll manufactured by Ishikawajima Sangyo Co., Ltd. to produce a printed sample piece. Apply white paper art paper to the color development surface of the printed sample piece immediately after the color development as a test sample, use a set tester to apply pressure to the top of the art paper of the test sample, The same operation is performed on the new part. During the repetition of this operation, the time (set time) from immediately after the color development until the printed paint film on the color-developed surface does not adhere to the blank art paper surface by coating film curing is measured. The coating film curability is determined from the above set time. That is, the shorter the set time, the better the coating film curability.

(Paint gloss)
Using each of the ink compositions obtained above, printing was performed with a normal offset sheet-fed printing press, and the obtained printed matter was allowed to stand at room temperature for 24 hours. Measurement was performed using a digital gloss meter (incident / reflection = 60 ° / 60 °) manufactured by Color Research Laboratory.

(Print image reproducibility)
Using each of the ink compositions obtained above, printing is performed with a normal offset sheet-fed printing press, and a printed matter is collected every certain number of sheets from the start of printing. The method was evaluated.
○: Image reproducibility is excellent with almost no change over time.
Δ: Image reproducibility is slightly inferior to the printed material, with slight roughness or poor ink deposit or slight change with time of printing (within practical range).
X: The image reproducibility is considerably inferior to the printed material due to roughness and poor ink deposit (outside the practical range).

(Ink-bonding stain resistance)
Using each of the ink compositions obtained above, 5,000 sheets were printed with a normal offset sheet-fed printing machine without spraying powder to prevent adhesion stains in the paper discharge section. After printing, the degree of ink adhesion stain between printed materials was evaluated by the following evaluation method.
◯: Ink adhesion stain resistance is good with almost no ink adhesion stain between printed materials.
Δ: Ink adhesion stain resistance is slightly inferior, with slight ink adhesion stains observed between printed materials.
X: Ink adhesion stain resistance is considerably inferior since ink adhesion stains are recognized between printed materials.

  From the above evaluation results, the ink composition of the present invention is excellent in the curability of the coating film, and in particular, the current ink composition having a standard composition penetrating and drying function conventionally used in Comparative Example 1. Compared to printed materials, the permeation drying time is very fast, and the effect of suppressing ink adhesion stains between printed materials is extremely good, and the gloss and image reproducibility are equivalent. On the other hand, as in Comparative Examples 2 and 3, an ink composition having improved penetrability by conventional formulation and a low aniline point as in Comparative Example 4, but due to its structure, it has a low molecular weight and a low boiling point. The ink composition to which the fatty acid monoester was added was inferior in coating film curability, ink adhesion stain resistance and printed image reproducibility.

  According to the present invention, the ink composition of the present invention has improved printing productivity by greatly improving the curability of the coating film, and the amount of spray powder sprayed to avoid ink adhesion stains has been increased. It is possible to effectively use as a sheet-fed offset ink having a penetrating and drying function that can improve printing quality and work environment by reduction and obtain printed matter of excellent quality.

Claims (6)

It contains at least a varnish in which a resin for varnish and a dissolution aid are dispersed and dissolved in an organic solvent,
The resin for varnish is a rosin-modified phenol resin and / or a rosin ester resin,
Before SL dissolution aid, a triester of at least one fatty acid and glycerin selected from caproic acid, caprylic acid and capric acid,
The organic solvent is a petroleum solvent,
Offset ink composition characterized by containing an amount of the dissolution aid, it occupies less than 0.1% by mass to 50% in the total varnish. Before kilometers Jin-modified phenolic resin and the rosin ester resin is, cloud point ink composition according to claim 1 below 200 ° C. or higher 50 ° C. and / or weight-average molecular weight of 80,000～500,000. The triester, tri (caprylic-capric) acid glycerides and / or ink composition according to claim 1 or 2 which is Torikapuron glycerides. Before Kiwanis further, the ink composition according to any one of claims 1 to 3 containing vegetable oils. Cloud point 100 ° C. to 180 ° C., and the weight and the rosin-modified phenolic resin and / or said rosin ester resin average molecular weight of 80,000 -, and the triester, dispersed and dissolved in petroleum solvents The ink composition according to any one of claims 1 to 4, which contains at least a varnish prepared. The ink composition according to any one of claims 1 to 5 , which is an offset ink having a penetration drying function.