ACTIVE ENERGY RAY-CURABLE LITHOGRAPHIC PRINTING INK, AND PRINTED MATTER

Abstract

An active energy ray-curable lithographic printing ink including a rosin-modified resin (A), an active energy ray-curable compound (B), a photopolymerization initiator (C), and an extender pigment (D), where the active energy ray-curable compound (B) includes dipentaerythritol hexaacrylate (B1), and an amount of the dipentaerythritol hexaacrylate (B1) relative to a total mass of the active energy ray-curable lithographic printing ink is within a range from 20 to 37% by mass. The photopolymerization initiator (C) includes at least two types of compounds selected from acylphosphine oxide-based compounds (C1), thioxanthone-based compounds (C2), and oxime ester-based compounds (C3), an amount of the extender pigment (D) relative to a total mass of the active energy ray-curable lithographic printing ink is within a range from 0.1 to 10% by mass, and a viscosity of the ink at 25° C. is within a range from 10 to 120 Pa.Math.s.

Claims

1. An active energy ray-curable lithographic printing ink comprising a rosin-modified resin (A), an active energy ray-curable compound (B), a photopolymerization initiator (C), and an extender pigment (D), wherein the rosin-modified resin (A) has a structural unit (a12) derived from a compound obtained by addition of an α,β-unsaturated carboxylic acid or acid anhydride thereof (A2) to a conjugated rosin acid (A1), a structural unit (a3) derived from an organic monobasic acid (A3) excluding the conjugated rosin acid (A1), and a structural unit (a5) derived from a polyol (A5), wherein a mass ratio between the structural unit (a12) and the structural unit (a3) is within a range from 100:10 to 100:350, the active energy ray-curable compound (B) includes dipentaerythritol hexaacrylate (B1), and an amount of the dipentaerythritol hexaacrylate (B1) relative to a total mass of the active energy ray-curable lithographic printing ink is within a range from 20 to 37% by mass, the photopolymerization initiator (C) includes at least two types of compounds selected from the group consisting of acylphosphine oxide-based compounds (C1), thioxanthone-based compounds (C2), and oxime ester-based compounds (C3), the extender pigment (D) includes at least one compound selected from the group consisting of calcium carbonate, magnesium carbonate, magnesium silicate and silicon dioxide, an amount of the extender pigment (D) relative to a total mass of the active energy ray-curable lithographic printing ink is within a range from 0.3 to 8% by mass, and a viscosity of the ink at 25° C. is within a range from 10 to 120 Pa.Math.s.

2. (canceled)

3. The active energy ray-curable lithographic printing ink according to claim 1, wherein the active energy ray-curable compound (B) also includes a polyfunctional acrylate (B2) having three or more acryloyl groups per molecule (but excluding dipentaerythritol hexaacrylate (B1)), and an amount of the polyfunctional acrylate (B2) relative to a total mass of the active energy ray-curable lithographic printing ink is within a range from 5 to 40% by mass.

4. The active energy ray-curable lithographic printing ink according to claim 1, wherein the photopolymerization initiator (C) also includes at least one compound selected from the group consisting of benzophenone-based compounds (C4) and alkylphenone-based compounds (C5).

5. The active energy ray-curable lithographic printing ink according to claim 1, further comprising an amine-based compound (E).

6. The active energy ray-curable lithographic printing ink according to claim 1, wherein the rosin-modified resin (A), when prepared as a mixture containing the rosin-modified resin (A), the dipentaerythritol hexaacrylate (B1) and trimethylolpropane triacrylate in a mass ratio of 30:35:35, has a viscosity at 25° C. within a range from 10 to 50 Pa.Math.s.

7. Printed matter having a printed layer formed using the active energy ray-curable lithographic printing ink according to claim 1.

8. The active energy ray-curable lithographic printing ink according to claim 1, wherein the extender pigment (D) is a combination of: (D1) at least one compound selected from the group consisting of calcium carbonate, magnesium carbonate and magnesium silicate; and (D2) silicon dioxide.

9. The active energy ray-curable lithographic printing ink according to claim 1, wherein an acid value of the rosin-modified resin (A) is within a range from 10 to 150 mgKOH/g.

Description

EXAMPLES

[0171] The present invention is described below in further detail using a series of examples, but the present invention is in no way limited by these examples. In the present description, “parts” indicates parts by mass, and “%” indicates % by mass.

1. Preparation of Binder Resins

1-1. Preparation of Rosin-Modified Resin (A)

[0172] In the preparation of the rosin-modified resins (A) described below, details relating to the component analysis of the rosins (gum rosins) used, the method used for confirming reaction progression, and the quantitative analysis and the like of the reaction products are as described below.

<Component Analysis of Rosin Acids>

[0173] The rosin acids used as raw materials were each analyzed by gas chromatography-mass spectrometry, and the surface area ratio (%) of each peak was determined relative to a value of 100% for the total peak surface area for the entire rosin acid. More specifically, the ratio between the conjugated rosin acid (A1) and the organic monobasic acid (A3) contained in the rosin acid was determined from the ratio between the surface areas of the corresponding peaks.

<Confirmation of Progression of Diels-Alder Addition Reaction, and Quantification of Produced Addition Reaction Product>

[0174] The reaction solution from the Diels-Alder addition reaction was analyzed by gas chromatography-mass spectrometry, and the progress of the reaction was confirmed by the decrease in the detection peaks for the conjugated rosin acid (A1) and the α,β-unsaturated carboxylic acid or acid anhydride thereof (A2) used as raw materials. When no further decrease in the detection peaks was observed, the reaction was halted.

[0175] Further, calibration curves were created in advance for the conjugated rosin acid (A1) contained in the rosin acid and the α,β-unsaturated carboxylic acid or acid anhydride thereof (A2), and the residual amount of each component left in the reaction solution was measured by fitting the peak surface area obtained in the above analysis to the prepared calibration curve at reaction completion. By then subtracting the residual amount of each component from the amount of that component used in the reaction, the amounts of the components (A1) and (A2) consumed in the Diels-Alder addition reaction were calculated. Moreover, by then adding these amounts of the components consumed in the Diels-Alder addition reaction, the mass of the compound having the structural unit (a12) obtained in the above addition reaction by adding the α,β-unsaturated carboxylic acid or acid anhydride thereof (A2) to the conjugated rosin acid (A1) was able to be calculated.

[0176] The molar quantity of the compound having the structural unit (a12) obtained by adding the α,β-unsaturated carboxylic acid or acid anhydride thereof (A2) to the conjugated rosin acid (A1) was deemed to be the smaller of the two molar quantities of the components consumed in the Diels-Alder addition reaction, each of which was calculated by dividing the previously calculated mass of the component (A1) or component (A2) consumed in the Diels-Alder addition reaction by the molecular weight of that component.

[0177] Furthermore, the molecular weight of the compound having the structural unit (a12) obtained in the Diels-Alder addition reaction can be calculated as the sum of the molecular weight of the component (A1) and the molecular weight of the component (A2).

<Confirmation of Amount of Each Structural Unit in Rosin-Modified Resin (A)>

[0178] In a similar manner to the quantification of the above compound having the structural unit (a12) (the Diels-Alder addition reaction product), the reaction solution obtained following the esterification reaction was analyzed by gas chromatography-mass spectrometry, and the peak surface areas for the organic monobasic acid (A3), the polybasic acid or anhydride thereof (A4) and the polyol (A5) were measured. By fitting these amounts to previously created calibration curves for each of these components, the residual amount of each component left in the reaction solution was measured. By then subtracting the residual amount of each component from the amount of that component used in the esterification reaction, the amounts of the various components consumed in the esterification reaction, namely the masses of the structural units (a3), (a4) and (a5) that exist in the rosin-modified resin (A), were able to be calculated.

[0179] Furthermore, for the residual components (A1) and (A2) that did not participate in the Diels-Alder addition reaction, a similar method to that described above was used to measure the residual amount of each component in the reaction solution obtained following the esterification reaction. By subtracting this residual amount of each component from the residual amount of the corresponding component (A1) or (A2) left in the reaction solution following the Diels-Alder addition reaction, the amounts of these components consumed in the esterification reaction, namely the masses of the structural units (a1) and (a2) that exist in the rosin-modified resin (A), were able to be calculated.

[0180] Moreover, for the compound having the structural unit (a12) obtained by adding the α,β-unsaturated carboxylic acid or acid anhydride thereof (A2) to the conjugated rosin acid (A1), a similar method to that described above was used to measure the amount of the residual component in the reaction solution following the esterification reaction. By subtracting this residual amount from the previously calculated mass of the compound having the structural unit (a12) obtained as a result of the Diels-Alder addition reaction, the amount of the component consumed in the esterification reaction, namely the mass of the structural unit (a12) that exist in the rosin-modified resin (A), was able to be calculated.

[0181] Then, by dividing the amount of each component consumed in the esterification reaction by the molecular weight of that component, the molar quantities for the various components consumed in the esterification reaction, namely the molar quantity of the structural unit (a12), and the molar quantity of each of the structural units (a1), (a2), (a3), (a4) and (a5) derived from the various components (monomers), were calculated for the rosin-modified resin (A) obtained following the esterification reaction.

[0182] In the preparation of the rosin-modified resins (A) described below, maleic anhydride was used as the α,β-unsaturated carboxylic acid or acid anhydride thereof (A2). Accordingly, in those cases where residual component (A2) remained after the Diels-Alder addition reaction, the rosin-modified resin (A) contained a structural unit (a2) derived from maleic anhydride. Furthermore, in those cases where an excess of maleic anhydride was used, and the polybasic acid or anhydride thereof (A4) was also used, the rosin-modified resin (A) contained both a structural unit (a2) derived from maleic anhydride and a structural unit (a4) derived from the polybasic acid or anhydride thereof (A4).

[0183] Details of the various measurements conducted relating to the properties of the resins obtained in the following preparations of the rosin-modified resins (A) are as follows.

(Weight Average Molecular Weight of Rosin-Modified Resin (A))

[0184] The weight average molecular weight (Mw) of the rosin-modified resin (A) was measured using a gel permeation chromatograph (HLC-8320) manufactured by Tosoh Corporation. A calibration curve was prepared using standard polystyrene samples. Further, tetrahydrofuran was used as the eluent, and three TSKgel Super HM-M columns (manufactured by Tosoh Corporation) were used as the columns. Measurement was performed under conditions including a flow rate of 0.6 mL/minute, an injection volume of 10 μL, and a column temperature of 40° C.

(Measurement of Viscosity of Rosin-Modified Resin (A))

[0185] A mixture was prepared by mixing the rosin-modified resin (A), dipentaerythritol hexaacrylate (B1) (product name: Laromer DPHA A-ap, manufactured by BASF Japan Ltd.) and trimethylolpropane triacrylate (product name: MIRAMER M300, manufactured by Miwon Specialty Chemical Co., Ltd.) in a mass ratio of 30:35:35, and the viscosity of the mixture was measured at 25° C. The viscosity measurement was conducted using a viscometer HAAKE RS600 manufactured by EKO Instruments Co., Ltd. equipped with a cone-and-plate sensor, using a measurement method employing the flow curve mode.

(Acid Value of Rosin-Modified Resin (A))

[0186] The acid value of the rosin-modified resin (A) was measured by a neutralization titration method. Specifically, first, 1 g of the rosin-modified resin (A) was dissolved in 20 mL of a solvent prepared by mixing xylene and ethanol in a mass ratio of 2:1. Subsequently, 3 mL of a 3% by mass solution of phenolphthalein was added as an indicator to the prepared solution of the rosin-modified resin (A), and a neutralization titration was then performed with a 0.1 mol/L ethanolic solution of potassium hydroxide. The units for the acid value are mgKOH/g.

(Preparation of Rosin-Modified Resin 1)

[0187] A four-neck flask fitted with a stirrer, a reflux condenser fitted with a water separator, and a thermometer was charged with 25 parts of the gum rosin and 7 parts of maleic anhydride, and by heating the contents to 180° C. over a period of one hour while the flask was flushed with nitrogen gas, a reaction mixture was obtained. Next, as described above, gas chromatography-mass spectrometry of the reaction mixture was used to confirm the completion point of the Diels-Alder addition reaction.

[0188] Subsequently, 40 parts of tert-butylbenzoic acid, 2 parts of succinic anhydride, 26 parts of neopentyl glycol, and 0.1 parts of p-toluenesulfonic acid monohydrate as a catalyst were added to the above reaction mixture, and a dehydration condensation reaction was conducted at 230° C. over a period of 14 hours, thus obtaining a rosin-modified resin 1 (R1).

[0189] The various measurements of the resin 1 (R1) were conducted in accordance with the methods described above. As shown in Table 1, the results revealed an acid value of 23 and a polystyrene-equivalent weight average molecular weight (Mw) measured by GPC of 2.5×10.sup.4. The proportions of the various structural units in the resin 1 (R1), calculated in accordance with the methods described above, were as shown in Table 1.

(Preparation of Rosin-Modified Resins 2 to 6)

[0190] With the exception of altering the formulation of the rosin-modified resin 1 (R1) to each of the respective formulations shown in Table 1, rosin-modified resins 2 to 6 (R2 to R6) were prepared in exactly the same manner as the preparation of the rosin-modified resin 1. Measurements and the like of the various properties of each of the obtained rosin-modified resins were conducted in the same manner as the rosin-modified resin 1. These results are shown in Table 1.

1-2. Preparation of Other Binder Resins

(Preparation of Resin A)

[0191] A four-neck flask fitted with a stirrer, a reflux condenser fitted with a water separator, and a thermometer was charged with 40 parts of 1,2,3,6-tetrahydrophthalic anhydride, 55 parts of hydrogenated bisphenol A and 5 parts of pentaerythritol, 0.1 parts of p-toluenesulfonic acid monohydrate were then added as a catalyst while the flask was flushed with nitrogen gas, and a dehydration condensation reaction was conducted at 200° C. over a period of 17 hours, thus obtaining a resin A (RA). Measurements and the like of the various properties of the obtained resin A (RA) were conducted in the same manner as the rosin-modified resin 1. These results are shown in Table 1.

(Resin B)

[0192] A sample of DAISO DAP A (a brand name for diallyl phthalate manufactured by Osaka Soda Co., Ltd.) was prepared as a binder resin B (RB), and the acid value, the polystyrene-equivalent weight average molecular weight (Mw) measured by GPC, and the viscosity were measured in the same manner as the rosin-modified resin 1. These results are shown in Table 1.

TABLE-US-00001 TABLE 1 Resin 1 Resin 2 Resin 3 Resin 4 Resin 5 Resin 6 Monomer Compound (R1) (R2) (R3) (R4) (R5) (R6) Formulation (A) (A2) Maleic anhydride 7 12 6 5 15 6.5 (A1) Gum rosin Conjugated double 20 24 16 14 40 20 bond-containing component (A3) Other component(s) 5 6 4 3.5 10 5 Benzoic acid tert-butylbenzoic acid 40 33 41 49 (A4) Succinic anhydride 2 1,2,3,6-tetrahydrophthalic anhydride 1,2-cyclohexanedicarboxylic 29 acid Phthalic anhydride 16.5 (A5) Neopentyl glycol 26 35 Polyethylene glycol 3 Hydrogenated bisphenol A Pentaerythritol 8 20 19.5 Glycerol 14 1,4-cyclohexanedimethanol 45 4-methoxyphenol Anilox M310 Total amount of resin raw materials 100 100 100 100 100 100 Catalyst p-toluenesulfonic acid monohydrate 0.1 0.1 0.1 0.1 0.1 0.1 Resin Weight average molecular weight (Mw) 2.5 × 10.sup.4 3.0 × 10.sup.4 0.45 × 10.sup.4 2.1 × 10.sup.4 0.52 × 10.sup.4 1.9 × 10.sup.4 properties Acid value 23 36 47 29 72 58 Composition Amount of structural 26.5 31.8 21.2 18.5 53.0 26.5 unit (a12) Amount of structural 169.9 122.7 18.9 240.0 18.9 203.9 unit (a3) relative to mass 100 of structural unit (a12) Proportion (mol %) of 3.4 5.6 54.2 32.9 3.1 0.02 structural units (a2), (a4) hydroxyl group/carboxyl group ratio 1.02 1.17 1.19 0.82 1.43 1.17 Viscosity 23.6 34.3 27.3 20.5 18.6 42.9 Resin A Resin B Resin C Resin D Resin E Resin F Monomer Compound (RA) (RB) (RC) (RD) (RE) (RF) Formulation (A) (A2) Maleic anhydride 4 (A1) Gum rosin Conjugated double 21.1 bond-containing component (A3) Other component(s) 5.3 Benzoic acid 25.1 tert-butylbenzoic acid (A4) Succinic anhydride 1,2,3,6-tetrahydrophthalic 40 19.2 anhydride 1,2-cyclohexanedicarboxylic acid Phthalic anhydride (A5) Neopentyl glycol Polyethylene glycol Hydrogenated bisphenol A 55 Pentaerythritol 5 17.6 Glycerol 1,4-cyclohexanedimethanol 4-methoxyphenol 0.1 Anilox M310 7.6 Total amount of resin raw materials 100 — — — — 100 Catalyst p-toluenesulfonic acid monohydrate 0.1 — — — — 0.3 Resin Weight average molecular weight (Mw) 1.8 × 10.sup.4 2.8 × 10.sup.4 4.5 × 10.sup.4 5.0 × 10.sup.4 0.61 × 10.sup.4 2.5 × 10.sup.4 properties Acid value 38  2.1 7   — — 21 Composition Amount of structural 0.0 — — — — 16.3 unit (a12) Amount of structural — — — — — 186.1 unit (a3) relative to mass 100 of structural unit (a12) Proportion (mol %) of 0.0 — — — — 25.7 structural units (a2), (a4) hydroxyl group/carboxyl group ratio 1.15 — — — — 0.82 Viscosity 89.1 83.6 91.4 — — 25.3

Notes:

[0193] In Table 1, the blend amounts shown for the various monomers used when preparing the rosin-modified resins (A) are all recorded as solid fraction mass values.

[0194] The proportions and amounts of the structural units shown in Table 1 are values obtained by analyzing the reaction solution by gas chromatography-mass spectrometry, and were calculated on a mass basis and a molar basis respectively in accordance with the methods described above. A summary is provided below.

[0195] The amount of the structural unit (a12) corresponds with the amount of the compound obtained as a result of the Diels-Alder addition reaction between the component (A1) and the component (A2), measured and calculated using the method described above.

[0196] The amount of the structural unit (a3) represents a value calculated based on the mass of the structural unit (a12) (which was deemed a mass of 100).

[0197] The proportion of the structural units (a2) and/or (a4) represents a proportion (mol %) calculated based on the amount of all the structural units other than the structural unit (a5).

[0198] In Table 1, the resin A and the resin B represent the resins obtained in the preparation examples described above, whereas the resins C to F are as follows.

[0199] Resin C: DIANAL BR116-27 (an acrylic resin) manufactured by Mitsubishi Chemical Corporation.

[0200] Resin D: MIRAMER SC9211 manufactured by Miwon Specialty Chemical Co., Ltd. This resin is a varnish composed of 40 parts by mass of an acrylic acrylate oligomer and 60 parts by mass of hexanediol diacrylate.

[0201] Resin E: MIRAMER PS2522 manufactured by Miwon Specialty Chemical Co., Ltd. This resin is a varnish composed of 75 parts by mass of a polyester acrylate oligomer and 25 parts by mass of dipropylene glycol diacrylate.

2. Preparation of Varnishes for Active Energy Ray-Curable Lithographic Printing Inks

(Preparation of Varnish 1)

[0202] A four-neck flask fitted with a stirrer, a reflux condenser fitted with a water separator, and a thermometer was charged with the rosin-modified resin 1 (R1) prepared above, dipentaerythritol hexaacrylate (B1) and hydroquinone in accordance with the formulation shown in Table 2, and following mixing, the mixture was heated and melted at 100° C. to obtain a vanish 1 (V1).

(Preparation of Varnishes 2 to 6)

[0203] With the exception of altering the formulation of the varnish 1 to each of the respective formulations shown in Table 2, varnishes 2 to 6 (V2 to V6) were obtained in exactly the same manner as the preparation of the varnish 1.

(Preparation of Varnishes A to D and G)

[0204] With the exception of altering the formulation of the varnish 1 to each of the respective formulations shown in Table 2, varnishes A to D and G (VA to VD and VG) were obtained in exactly the same manner as the preparation of the varnish 1.

[0205] Varnish E and varnish F (VE and VF) correspond with the components of the resin E and the resin F respectively described above.

TABLE-US-00002 TABLE 2 Varnish 1 Varnish 2 Varnish 3 Varnish 4 Varnish 5 Varnish 6 (V1) (V2) (V3) (V4) (V5) (V6) Resin Type Resin 1 Resin 2 Resin 3 Resin 4 Resin 5 Resin 6 (R1) (R2) (R3) (R4) (R5) (R6) Formulation (A) Resin 33.0 31.0 50.0 36.0 40.0 27.0 amount (B) (B1) Dipentaerythritol 66.9 68.9 44.9 63.9 55.0 58.0 hexaacrylate (B2) Trimethylolpropane 4.9 4.9 14.9 triacrylate Hexanediol diacrylate Dipropylene glycol diacrylate Polymerization Hydroquinone 0.1 0.1 0.1 0.1 0.1 0.1 inhibitor Total 100 100 100 100 100 100 Varnish A Varnish B Varnish C Varnish D Varnish E Varnish F Varnish G (VA) (VB) (VC) (VD) (VE) (VF) (VG) Resin Type Resin A Resin B Resin 1 Resin C Resin D Resin E Resin F (RA) (RB) (R1) (RC) (RD) (RE) (RF) Formulation (A) Resin 25.0 20.0 36.0 21.0 40.0 75.0 30.0 amount (B) (B1) Dipentaerythritol hexaacrylate 32.0 35.0 33.0 30.0 69.9 (B2) Trimethylolpropane triacrylate 42.9 44.9 30.9 48.9 Hexanediol diacrylate 60.0 Dipropylene glycol diacrylate 25.0 Polymerization Hydroquinone 0.1 0.1 0.1 0.1 0.1 inhibitor Total 100 100 100 100 100 100 100

3. Preparation of Active Energy Ray-Curable Lithographic Printing Inks

[0206] Details of the pigments used in preparing the various inks described below are as follows.

<Pigments>

[0207] Pigment Blue 15:3: product name: LIONOL BLUE FG-7330, manufactured by TOYOCOLOR Co., Ltd.

[0208] Pigment Yellow 13: product name: LIONOL YELLOW 1314, manufactured by TOYOCOLOR Co., Ltd.

[0209] Pigment Red 57:1: product name: No. 6516 Carmine 6B, manufactured by Daido Chemical Corporation

[0210] Carbon Black: product name: SPECIAL BLACK 550, manufactured by Orion Engineered Carbons GmbH

(Preparation of Example Ink 1)

[0211] Fifty parts of the previously prepared varnish (V1), 19 parts of LIONOL BLUE FG-7330 (an indigo pigment manufactured by TOYOCOLOR Co., Ltd.), 3 parts of magnesium carbonate, 15 parts of trimethylolpropane triacrylate, 8.9 parts of ditrimethylolpropane tetraacrylate, 2 parts of 2,4,6-trimethylbenzoyl diphenylphosphine oxide, 2 parts of 1,2-octanedione, 1-[4-(phenylthio)phenyl]-, 2-(O-benzoyloxime), and 0.1 parts of hydroquinone were kneaded at 40° C. in a triple roll mill to obtain an active energy ray-curable lithographic printing ink 1 (C1).

[0212] The viscosity of the ink 1 (C1) at 25° C. was measured. The viscosity measurement was conducted using a viscometer HAAKE RS600 manufactured by EKO Instruments Co., Ltd. equipped with a cone-and-plate sensor, using a measurement method employing the flow curve mode. As shown in Table 3, the result revealed a viscosity of 60 Pa.Math.s.

(Preparation of Example Inks 2 to 25)

[0213] With the exception of altering the formulation of the ink 1 (C1) to each of the respective formulations shown in Table 3, inks 2 to 22 (C2 to C22), an ink 23 (Y1), an ink 24 (M1) and an ink 25 (K1) were obtained in exactly the same manner as the ink 1.

[0214] The viscosity of each of the obtained inks was measured in the same manner as the ink 1 (C1). These results are shown in Table 3.

(Preparation of Comparative Example Inks A to M)

[0215] With the exception of altering the formulation of the ink 1 (C1) to each of the respective formulations shown in Table 3, inks A to M (CA to CM) were obtained in exactly the same manner as the ink 1.

[0216] The viscosity of each of the obtained inks was measured in the same manner as the ink 1 (C1). These results are shown in Table 3.

4. Evaluations of Active Energy Ray-Curable Lithographic Printing Inks

[0217] Each of the active energy ray-curable lithographic printing inks prepared in the examples and comparative examples was evaluated for printed coating film applicability and printability in accordance with the methods described below.

<Evaluation of Printed Coating Film Applicability>

[0218] Using an RI Tester (a simple color development device manufactured by Mei Seisakusho Co., Ltd.), each of the active energy ray-curable lithographic printing inks obtained in the examples and comparative examples was printed onto Maricoat paper (a coated cardboard manufactured by Hokuetsu Corporation) at a coating amount of 1 g/m.sup.2. Subsequently, the printed surface was irradiated with ultraviolet rays at 60 m/min using a single 120 W/cm air-cooled metal halide lamp (manufactured by Toshiba Corporation), thus obtaining printed matter.

[0219] Further, in order to prepare a sample for evaluating the curability and adhesiveness as described below, printed matter was also obtained by conducting the irradiation of ultraviolet rays at 100 m/min using a 17 W/cm.sup.2 LED lamp (XP9-I. manufactured by AMS Spectral UV Co., Ltd. instead of the above air-cooled metal halide lamp.

[0220] Following ultraviolet ray irradiation, the printed matter was evaluated for curability, solvent resistance, abrasion resistance, blocking resistance and glossiness in accordance with the methods described below. The results of these evaluation are shown in Table 4.

(Curability)

[0221] The curability was evaluated for both the printed matter obtained using the air-cooled metal halide lamp and the printed matter obtained using the LED lamp. The curability was evaluated on a 5-grade scale against the criteria described below, by visually inspecting the state of the printed surface of the printed matter upon rubbing with a cotton cloth. An evaluation of 3 or higher represents a usable level, but an evaluation of 4 or higher is more preferable.

[0222] 5: no change to the printed surface.

[0223] 4: no scratches observed on the printed surface, but color detected on cotton cloth.

[0224] 3: scratches observed on part of the printed surface, but no detachment observed.

[0225] 2: detachment observed on part (less than 50%) of the printed surface.

[0226] 1: detachment observed on part (at least 50%) or all of the printed surface.

(Solvent Resistance)

[0227] The solvent resistance was evaluated on a 5-grade scale against the criteria described below, by rubbing a cotton swab that had been dipped in MEK (methyl ethyl ketone) 30 times across the printed surface, and then visually inspecting the state of the printed surface. An evaluation of 3 or higher represents a usable level, but an evaluation of 4 or higher is more preferable.

[0228] 5: no change to the printed surface.

[0229] 4: almost no change observed on the printed surface, but slight coloring of the cotton swab.

[0230] 3: dissolution observed on part of the printed surface, but no detachment observed.

[0231] 2: detachment observed on part (less than 50%) of the printed surface.

[0232] 1: detachment observed on part (at least 50%) or all of the printed surface.

(Abrasion Resistance)

[0233] The abrasion resistance was evaluated by testing the printed surface (coating film) of the printed matter in accordance with JIS K5701-1. Specifically, using a Gakushin-type rubbing fastness tester (manufactured by Tester Sangyo Co., Ltd.), 500 back and forth rubbing repetitions across the coating film surface were performed using a high-quality paper as the rubbing paper with a 500 g weight applied. The rubbed surface (coating film surface) was then inspected visually for change, and the abrasion resistance was evaluated on a 5-grade scale against the criteria described below. An evaluation of 3 or higher represents a usable level, but an evaluation of 4 or higher is more preferable.

[0234] 5: no change in the rubbed surface

[0235] 4: no scratches observed on the rubbed surface, but some color transfer to the high-quality paper.

[0236] 3: scratches observed on part of the rubbed surface, but no detachment observed.

[0237] 2: detachment observed on part (less than 50%) of the rubbed surface.

[0238] 1: detachment observed on part (at least 50%) or all of the rubbed surface.

(Blocking Resistance)

[0239] Two sheets of printed matter were superimposed with the printed surfaces facing each another, and a load equivalent to a force of 1 kg/cm.sup.2 was then applied for 24 hours in an environment at 40° C. and 80% humidity. After 24 hours, the sheets of printed matter were separated and inspected visually for change to the printed surfaces, with the blocking resistance evaluated on a 5-grade scale against the criteria described below. An evaluation of 3 or higher represents a usable level, but an evaluation of 4 or higher is more preferable.

[0240] 5: no changes, with no sticking of printed matter.

[0241] 4: no changes to printed matter, but some sticking, with sound noticeable upon peeling.

[0242] 3: printed matter sticks together, and some slight transfer to opposing surface, with white paper patches visible.

[0243] 2: printed matter sticks together, and transfer to opposing surface, with white paper patches visible across entire printed matter.

[0244] 1: printed matter sticks tightly together, with detachment of printed matter upon peeling.

(Glossiness)

[0245] Using a Prufbau printability tester, each ink was printed onto Pearl Coat paper manufactured by Mitsubishi Paper Mills Ltd. at a uniform density, thus preparing a test sample. Subsequently, a Gloss Meter model GM-26 (manufactured by Murakami Color Research Laboratory Co., Ltd.) was used to measure the 60° gloss value of the test sample. A higher numerical gloss value indicates superior glossiness. Based on the obtained gloss value, the glossiness was evaluated on a 5-grade scale against the criteria described below. An evaluation of 3 or higher represents a usable level, but an evaluation of 4 or higher is more preferable.

[0246] 5: gloss value of 60 or higher.

[0247] 4: gloss value of at least 50 but less than 60.

[0248] 3: gloss value of at least 40 but less than 50.

[0249] 2: gloss value of at least 30 but less than 40.

[0250] 1: gloss value of less than 30.

[0251] Further, using an RI Tester (a simple color development device manufactured by Mei Seisakusho Co., Ltd.), each of the active energy ray-curable lithographic printing inks obtained in the examples and comparative examples was printed onto a PP film at a coating amount of 1 g/m.sup.2. Subsequently, the printed surface was irradiated with ultraviolet rays at 60 m/min using a single 120 W/cm air-cooled metal halide lamp (manufactured by Toshiba Corporation), thus obtaining printed matter. Printed matter were also obtained using the same method as above, but using a PET film instead of the PP film.

[0252] The adhesiveness of each of the printed matter samples obtained using the air-cooled metal halide lamp and the LED lamp was evaluated in the manner described below. The evaluation results are shown in Table 4.

(Adhesiveness)

[0253] For each of the printed matter samples on PP film and PET film obtained in the manner described above, the adhesiveness was evaluated by performing a cellophane peel test. The surface of the printed matter following the test was inspected visually, and the adhesiveness was evaluated on a 5-grade scale against the criteria described below. An evaluation of 3 or higher represents a usable level, but an evaluation of 4 or higher is more preferable.

[0254] 5: no change in the printed surface

[0255] 4: peeling observed on part (less than 10%) of the printed surface.

[0256] 3: peeling observed on part (less than 25%) of the printed surface.

[0257] 2: peeling observed on part (at least 25% but less than 50%) of the printed surface.

[0258] 1: peeling observed on part (at least 50%) or all of the printed surface.

<Evaluation of Printability>

[0259] Using each of the active energy ray-curable lithographic printing inks obtained in the examples and comparative examples, a printing test was performed by printing 20,000 copies using the ink. The printing test was conducted by using a LITHRONE 226 (a sheet-fed printing press, manufactured by Komori Corporation) to print to Mitsubishi special art paper having a weight of 90 kg/ream (manufactured by Mitsubishi Paper Mills Ltd.) under conditions including a printing speed of 10,000 copies/hour.

[0260] Furthermore, in the printing test, tap water containing 1.5% of Astro Mark III Clear (manufactured by Toyo Ink SC Holdings Co., Ltd.) and 3% of isopropyl alcohol was used as the dampening water. In order to enable comparison of the printed state near the boundaries of the range of conditions under which normal printing can be performed, printing was performed at a water dial value 2% higher than the water tolerance lower limit. Here, the “water tolerance lower limit” means the minimum dampening water supply volume at which normal printing can be performed, and the “water dial” means the dial provided on the printing press for adjusting the supply volume of dampening water.

[0261] The printed matter samples obtained in the printing test were compared for the state of the solid printed areas, but no marked differences were observed between the printed matter prepared using the inks 1 to 20 of the examples and the inks A to I of the comparative examples.

[0262] Furthermore, in the printing test described above, based on the number of waste sheets generated at the start of printing until density fluctuations stabilized, the initial density stability was evaluated on a 5-grade scale against the criteria described below. An evaluation of 3 or higher represents a usable level, but an evaluation of 4 or higher is more preferable. The evaluation results are shown in Table 4.

(Evaluation Criteria for Initial Density Stability)

[0263] 5: number of waste sheets of 100 or fewer.

[0264] 4: number of waste sheets of at least 101 but not more than 200.

[0265] 3: number of waste sheets of at least 201 but not more than 500.

[0266] 2: number of waste sheets of at least 501 but not more than 800.

[0267] 1: number of waste sheets of 801 or more.

(Scumming Resistance)

[0268] In the above printing test, as the number of printed copies increases, ink gradually adheres to the roller used for supplying the dampening water. Further, as the supply volume of dampening water is reduced, ink becomes more likely to adhere to the non-printed area (the area to which ink should not adhere) that constitutes part of the image formation on the printed matter. As a result of these factors, scumming of the printed matter becomes more likely as the number of printed copies increases. Resistance to this type of scumming was evaluated by conducting printing in the same manner as the printing test described above, with the water dial set to a water dial value 2% higher than the water tolerance lower limit, and the printed matter was then inspected visually, with the scumming resistance evaluated on a 5-grade scale against the criteria described below. An evaluation of 3 or higher represents a usable level, but an evaluation of 4 or higher is more preferable.

[0269] 5: no particular scumming could be confirmed after printing 20,000 copies.

[0270] 4: slight scumming visible at the paper edges during printing of 20,000 copies, but scumming eliminated by increasing water dial.

[0271] 3: water dial increased during printing of 20,000 copies, but slight scumming visible at the paper edges.

[0272] 2: before printing 20,000 copies, scumming could not be eliminated without cleaning ink adhered to the roller.

[0273] 1: before printing 20,000 copies, scumming could not be eliminated without cleaning ink adhered to the roller multiple times.

(Misting Resistance)

[0274] A white sheet of paper was affixed to the inside of the safety cover of the printing press during the above printing test, and 10,000 copies were printed. The white sheet of paper was then removed, the degree of ink scattering was inspected visually, and the misting resistance was evaluated on a 5-grade scale against the criteria described below. An evaluation of 3 or higher represents a usable level, but an evaluation of 4 or higher is more preferable.

[0275] 5: almost no ink mist detected on the white sheet of paper.

[0276] 4: a small amount of ink mist scattered on a portion of the white sheet of paper.

[0277] 3: a thin layer of ink mist scattered across the entire white sheet of paper.

[0278] 2: a fairly thick layer of ink mist scattered across the entire white sheet of paper.

[0279] 1: a thick layer of ink mist scattered across the entire white sheet of paper.

TABLE-US-00003 TABLE 3 Example Ink 1 Ink 2 Ink 3 Ink 4 Ink 5 Ink 6 (C1) (C2) (C3) (C4) (C5) (C6) Varnish used Varnish 1 Varnish 2 Varnish 3 Varnish 4 Varnish 5 Varnish 6 (V1) (V2) (V3) (V4) (V5) (V6) Formulation Varnish Varnish 50 50 50 50 50 50 Pigment Pigment Blue 15:3 19 19 19 19 19 19 Pigment Yellow 13 Pigment Red 57:1 Carbon Black (B) (B1) Dipentaerythritol hexaacrylate (B2) Trimethylolpropane 15 15 15 15 15 15 triacrylate Ditrimethylolpropane 8.9 8.9 8.9 8.9 8.9 8.9 tetraacrylate (C) (C1) 2,4,6-trimethylbenzoyl 2 2 2 2 2 2 diphenylphosphine oxide (C2) 2,4-diethylthioxanthone (C3) 1,2-octanedione, 2 2 2 2 2 2 1-[4-(phenylthio) phenyl]-, 2-(O-benzoyloxime) (C4) Methyl o-benzoylbenzoate (C5) 2-methyl-1- (4-methylthiophenyl)-2- morpholinopropan-1-one (D) Magnesium carbonate 3 3 3 3 3 3 Calcium carbonate Magnesium silicate (E) Ethyl 4-dimethylaminobenzoate Polymerization Hydroquinone 0.1 0.1 0.1 0.1 0.1 0.1 inhibitor Total 100 100 100 100 100 100 Ink viscosity 60 65 49 56 52 53 Amount of dipentaerythritol 33.5 34.5 22.5 32.0 27.5 29.0 hexaacrylate (B1) Amount of active energy 57.4 58.4 48.8 55.9 53.9 60.4 ray-curable compound (B) Amount of (B2) 23.9 23.9 26.3 23.9 26.4 31.4 Amount of resin 16.5 15.5 25.0 18.0 20.0 13.5 Example Ink 7 Ink 8 Ink 9 Ink 10 Ink 11 Ink 12 (C7) (C8) (C9) (C10) (C11) (C12) Varnish used Varnish 1 Varnish 1 Varnish 1 Varnish 1 Varnish 1 Varnish 1 (V1) (V1) (V1) (V1) (V1) (V1) Formulation Varnish Varnish 50 50 54.6 43 50 50 Pigment Pigment Blue 15:3 19 19 19 19 19 19 Pigment Yellow 13 Pigment Red 57:1 Carbon Black (B) (B1) Dipentaerythritol hexaacrylate (B2) Trimethylolpropane 15 15 15 15 15 15 triacrylate Ditrimethylolpropane 8.9 8.9 7 10.9 8.9 8.9 tetraacrylate (C) (C1) 2,4,6-trimethylbenzoyl 2 2 2 2 2 diphenylphosphine oxide (C2) 2,4-diethylthioxanthone 2 2 (C3) 1,2-octanedione, 2 2 2 2 2 1-[4-(phenylthio) phenyl]-, 2-(O-benzoyloxime) (C4) Methyl o-benzoylbenzoate (C5) 2-methyl-1- (4-methylthiophenyl)-2- morpholinopropan-1-one (D) Magnesium carbonate 3 3 0.3 8 Calcium carbonate 3 Magnesium silicate 3 (E) Ethyl 4-dimethylaminobenzoate Polymerization Hydroquinone 0.1 0.1 0.1 0.1 0.1 0.1 inhibitor Total 100 100 100 100 100 100 Ink viscosity 60 60 47 81 65 55 Amount of dipentaerythritol 33.5 33.5 36.5 28.8 33.5 33.5 hexaacrylate (B1) Amount of active energy 57.4 57.4 58.5 54.7 57.4 57.4 ray-curable compound (B) Amount of (B2) 23.9 23.9 22.0 25.9 23.9 23.9 Amount of resin 16.5 16.5 18.0 14.2 16.5 16.5 Example Ink 13 Ink 14 Ink 15 Ink 16 Ink 17 Ink 18 Ink 19 (C13) (C14) (C15) (C16) (C17) (C18) (C19) Varnish used Varnish 1 Varnish 1 Varnish 1 Varnish 1 Varnish 1 Varnish 1 Varnish 1 (V1) (V1) (V1) (V1) (V1) (V1) (V1) Formulation Varnish Varnish 49 49 49 49.9 48 38 46.5 Pigment Pigment Blue 15:3 19 19 19 19 19 19 19 Pigment Yellow 13 Pigment Red 57:1 Carbon Black (B) (B1) Dipentaerythritol hexaacrylate (B2) Trimethylolpropane 15 15 15 15 15 20 15 triacrylate Ditrimethylolpropane 8.9 8.9 8.9 7 8.9 15.9 7.4 tetraacrylate (C) (C1) 2,4,6-trimethylbenzoyl 2 2 2 2 2 2 2 diphenylphosphine oxide (C2) 2,4-diethylthioxanthone 2 (C3) 1,2-octanedione, 2 2 2 2 2 2 2 1-[4-(phenylthio) phenyl]-, 2-(O-benzoyloxime) (C4) Methyl o-benzoylbenzoate (C5) 2-methyl-1- (4-methylthiophenyl)-2- morpholinopropan-1-one (D) Magnesium carbonate 3 3 3 3 8 Calcium carbonate 3 Magnesium silicate 3 Silicon dioxide 1 1 1 (E) Ethyl 2 4-dimethylaminobenzoate Polymerization Hydroquinone 0.1 0.1 0.1 0.1 0.1 0.1 0.1 inhibitor Total 100 100 100 100 100 100 100 Ink viscosity 68 73 63 65 65 15 117 Amount of dipentaerythritol 32.8 32.8 32.8 33.4 32.1 25.4 31.1 hexaacrylate (B1) Amount of active energy 56.7 56.7 56.7 55.4 56.0 61.3 53.5 ray-curable compound (B) Amount of (B2) 23.9 23.9 23.9 22.0 23.9 35.9 22.4 Amount of resin 16.2 16.2 16.2 16.5 15.8 12.5 15.3 Example Ink 20 Ink 21 Ink 22 Ink 23 Ink 24 Ink 25 (C20) (C21) (C22) (Y1) (M1) (K1) Varnish used Varnish 1 Varnish 1 Varnish 1 Varnish 1 Varnish 1 Varnish 1 (V1) (V1) (V1) (V1) (V1) (V1) Formulation Varnish Varnish 49.9 49.9 50 52 52 47 Pigment Pigment Blue 15:3 19 19 19 Pigment Yellow 13 13 Pigment Red 57:1 17 Carbon Black 20 (B) (B1) Dipentaerythritol hexaacrylate (B2) Trimethylolpropane 15 15 23.9 15 15 15 triacrylate Ditrimethylolpropane 7 7 8.9 8.9 10.9 tetraacrylate (C) (C1) 2,4,6-trimethylbenzoyl 2 2 2 2 2 2 diphenylphosphine oxide (C2) 2,4-diethylthioxanthone (C3) 1,2-octanedione, 2 2 2 2 2 2 1-[4-(phenylthio) phenyl]-, 2-(O-benzoyloxime) (C4) Methyl 2 o-benzoylbenzoate (C5) 2-methyl-1- 2 (4-methylthiophenyl)-2- morpholinopropan-1-one (D) Magnesium carbonate 3 3 3 7 3 3 Calcium carbonate Magnesium silicate Silicon dioxide (E) Ethyl 4-dimethylaminobenzoate Polymerization Hydroquinone 0.1 0.1 0.1 0.1 0.1 0.1 inhibitor Total 100 100 100 100 100 100 Ink viscosity 65 65 37 42 56 52 Amount of dipentaerythritol 33.4 33.4 33.5 34.8 34.8 31.4 hexaacrylate (B1) Amount of active energy 55.4 55.4 57.4 58.7 58.7 57.3 ray-curable compound (B) Amount of (B2) 22.0 22.0 23.9 23.9 23.9 25.9 Amount of resin 16.5 16.5 16.5 17.2 17.2 15.5 Comparative Example Ink A Ink B Ink C Ink D Ink E Ink F Ink G (CA) (CB) (CC) (CD) (CE) (CF) (CG) Varnish used Varnish A Varnish B Varnish C Varnish D Varnish E Varnish F Varnish 1 (VA) (VB) (VC) (VD) (VE) (VF) (V1) Formulation Varnish Varnish 51 50 50 50 48 55 53.9 Pigment Pigment Blue 15:3 19 19 19 19 19 19 19 Pigment Yellow 13 Pigment Red 57:1 Carbon Black (B) (B1) Dipentaerythritol 4 3 3 15 15 2.5 hexaacrylate (B2) Trimethylolpropane 13 15 15 15 8.9 1.9 15 triacrylate Ditrimethylolpropane 5.9 5.9 8.9 5.9 4.5 tetraacrylate (C) (C1) 2,4,6-trimethylbenzoyl 2 2 2 2 2 2 2 diphenylphosphine oxide (C2) 2,4-diethylthioxanthone (C3) 1,2-octanedione, 2 2 2 2 2 2 2 1-[4-(phenylthio) phenyl]-, 2-(O-benzoyloxime) (C4) Methyl o-benzoylbenzoate (C5) 2-methyl-1- (4-methylthiophenyl)-2- morpholinopropan-1-one (D) Magnesium carbonate 3 3 3 3 5 5 1 (E) Ethyl 4-dimethylaminobenzoate Polymerization Hydroquinone 0.1 0.1 0.1 0.1 0.1 0.1 0.1 inhibitor Total 100 100 100 100 100 100 100 Ink viscosity 35 65 51 72 45 35 50 Amount of dipentaerythritol 20.3 20.5 16.5 3.0 15.0 15.0 38.6 hexaacrylate (B1) Amount of active energy 62.1 63.9 55.9 23.9 23.9 16.9 58.1 ray-curable compound (B) Amount of (B2) 41.8 43.4 39.4 20.9 8.9 1.9 19.5 Amount of resin 12.8 10.0 18.0 0.0 0.0 0.0 17.8 Comparative Example Ink H Ink I Ink J Ink K Ink L Ink M (CH) (CI) (CJ) (CK) (CL) (CM) Varnish used Varnish 1 Varnish 1 Varnish 1 Varnish 1 Varnish 1 Varnish G (V1) (V1) (V1) (V1) (V1) (VG) Formulation Varnish Varnish 53.9 37 50 33 48 53.9 Pigment Pigment Blue 15:3 19 19 19 19 19 19 Pigment Yellow 13 Pigment Red 57:1 Carbon Black (B) (B1) Dipentaerythritol hexaacrylate (B2) Trimethylolpropane 15 15 15 21 15 15 triacrylate Ditrimethylolpropane 8 12.9 6.9 19.9 5.9 8 tetraacrylate (C) (C1) 2,4,6-trimethylbenzoyl 2 2 6 2 2 2 diphenylphosphine oxide (C2) 2,4-diethylthioxanthone (C3) 1,2-octanedione, 2 2 2 2 2 1-[4-(phenylthio) phenyl]-, 2-(o-benzoyloxime) (C4) Methyl o-benzoylbenzoate (C5) 2-methyl-1- (4-methylthiophenyl)-2- morpholinopropan-1-one (D) Magnesium carbonate 12 3 3 8 (E) Ethyl 4-dimethylaminobenzoate Polymerization Hydroquinone 0.1 0.1 0.1 0.1 0.1 0.1 inhibitor Total 100 100 100 100 100 100 Ink viscosity 45 94 69 8.5 130 43 Amount of dipentaerythritol 36.1 24.8 33.5 22.1 32.1 37.7 hexaacrylate (B1) Amount of active energy 59.1 52.7 55.4 63.0 53.0 60.7 ray-curable compound (B) Amount of (B2) 23.0 27.9 21.9 40.9 20.9 23.0 Amount of resin 17.8 12.2 16.5 10.9 15.8 16.2

TABLE-US-00004 TABLE 4 Example Ink 1 Ink 2 Ink 3 Ink 4 Ink 5 Ink 6 Ink 7 Ink 8 Ink 9 Ink 10 Ink 11 Ink 12 (C1) (C2) (C3) (C4) (C5) (C6) (C7) (C2) (C9) (C10) (C11) (C12) Curability (metal 4 4 3 4 3 4 4 4 4 4 4 4 halide) Curability (LED) 5 5 4 5 4 4 5 5 5 5 5 5 MEK resistance 5 5 3 4 3 4 5 5 5 4 5 5 Abrasion resistance 4 5 4 4 4 4 4 4 5 4 4 4 Blocking resistance 5 5 4 4 4 3 5 5 4 4 4 4 Gloss value 4 5 5 5 5 3 4 4 5 3 4 4 Adhesiveness (metal 4 4 5 4 5 4 4 4 4 3 4 4 halide) Adhesiveness (LED) 3 3 5 4 4 3 3 3 3 3 3 3 Misting resistance 4 4 4 4 4 4 4 4 3 5 5 4 Scumming resistance 5 5 4 5 4 4 5 5 5 4 5 4 Initial density 4 4 5 4 5 3 4 4 4 3 4 4 stability Example Ink 13 Ink 14 Ink 15 Ink 16 Ink 17 Ink 18 Ink 19 Ink 20 Ink 21 Ink 22 Ink 23 Ink 24 Ink 25 (C13) (C14) (C15) (C16) (C17) (C18) (C19) (C20) (C21) (C22) (Y1) (M1) (K1) Curability (metal 4 4 4 5 5 4 4 4 3 4 4 4 4 halide) Curability (LED) 5 5 5 5 5 5 4 5 4 5 5 5 5 MEK resistance 5 5 5 5 5 5 5 5 3 4 5 5 4 Abrasion resistance 4 4 4 5 4 5 5 5 4 4 5 5 5 Blocking resistance 5 4 4 5 5 4 4 5 4 4 5 4 4 Gloss value 3 3 3 3 4 3 4 4 5 4 5 5 5 Adhesiveness (metal 4 4 4 4 4 4 3 4 4 4 4 4 3 halide) Adhesiveness (LED) 3 3 3 3 3 3 3 3 4 4 3 3 3 Misting resistance 5 5 5 4 4 4 4 4 4 3 4 4 4 Scumming resistance 5 5 5 4 4 5 5 5 4 4 4 4 4 Initial density 5 5 5 3 4 4 4 4 4 4 5 4 5 stability Comparative Example Ink A Ink B Ink C Ink D Ink E Ink F Ink G Ink H Ink I Ink J Ink K Ink L Ink M (CA) (CB) (CC) (CD) (CE) (CF) (CG) (CH) (CI) (CJ) (CK) (CL) (CM) Curability (metal 1 2 1 3 2 2 4 4 3 3 2 3 4 halide) Curability (LED) 2 3 2 4 3 2 5 5 4 4 3 3 5 MEK resistance 1 2 1 2 3 2 5 4 3 3 2 3 4 Abrasion resistance 2 2 2 2 2 2 3 3 3 3 2 3 3 Blocking resistance 3 4 2 2 3 2 4 3 3 2 3 3 3 Gloss value 3 2 4 1 2 2 4 5 2 3 4 2 3 Adhesiveness (metal 2 2 4 2 4 3 2 3 3 2 3 3 2 halide) Adhesiveness (LED) 2 1 3 1 3 3 2 2 2 2 3 3 1 Misting resistance 1 2 3 1 2 3 1 1 4 3 2 5 2 Scumming resistance 3 3 3 1 1 2 2 1 2 3 1 2 3 Initial density 3 3 3 1 1 1 3 3 1 3 1 1 2 stability

[0280] As shown in Table 4, the inks 1 to 25 of the examples that correspond with embodiments of the present invention exhibited usable levels for all of the evaluations, and it was evident that the inks had excellent printability and were able to form coating films having excellent printed coating film applicability and printed coating film strength. In contrast, in the case of the inks A to L of the comparative examples, for example, the curability and/or the adhesiveness were inferior, and at least one of the printability, printed coating film applicability and printed coating film strength did not reach a usable level.

[0281] More specifically, as is evident upon comparison with the inks A to F of the comparative examples which used typical lithographic printing ink binder resins, the inks 1 to 25 of the examples that correspond with embodiments of the present invention exhibited markedly lower viscosity values for the rosin-modified resin (A). As a result, in the inks of the examples, the blend amount of the dipentaerythritol hexaacrylate (DPHA) (B1) was able to be increased significantly.

[0282] Usually, increasing the blend amount of the dipentaerythritol hexaacrylate (B1) in an ink increases the likelihood of a deterioration in the flexibility of the printed coating film, meaning curing shrinkage of the printed coating film becomes more likely, and other problems such as a deterioration in the adhesiveness are more likely to occur. However, as is evident from a comparison of the inks 1 to 25 of the examples and, for example, the inks C to F of the comparative examples, in the present invention, by using a prescribed amount of DPHA (B1) and a prescribed amount of the extender pigment (D), the printability, printed coating film applicability and printed coating film strength were able to be improved with good balance. In contrast, in the inks C to F of the comparative examples, the blend amount of DPHA (B1) was less than the prescribed range, whereas in inks G and M of the comparative examples, the blend amount of DPHA exceeded the prescribed range. Further, the inks H and M of the comparative examples did not contain the extender pigment (D), and the ink I of the comparative example had a blend amount of the extender pigment (D) that exceeded the prescribed range. The ink M corresponds with an embodiment that uses the resin disclosed in Patent Document 3 (Example 1 of JP 2016-190907 A), and contains no extender pigment. The ink M, although exhibiting excellent curability, displayed inferior results for the printability and printed coating film applicability, including the adhesiveness, misting resistance and initial density stability. The adhesiveness was particularly poor, and it was evident that using a prescribed amount of the extender pigment in the inks of the examples enabled a significant improvement in the adhesiveness.

[0283] Furthermore, as is evident from a comparison of the inks 1, 7 and 8 of the examples with the ink J of the comparative example, using a combination of two or more specified types of photopolymerization initiator (C) facilitated the improvement in curability. Moreover, as is clear from the inks K and L of the comparative examples, adjusting the viscosity of the ink to a value within the prescribed range facilitates improvements in the printed coating film applicability and printed coating film strength, while maintaining excellent printability.

[0284] Further, in general, as the blend amount of binder resin in an ink is increased, the curability tends to be prone to deterioration. However, as is evident, for example, by comparison of the inks 1 to 6 of the examples with the inks B, D and C of the comparative examples, by using the rosin-modified resin (A) as a binder resin, excellent curability can be achieved regardless of whether the blend amount of binder resin is large. Moreover, it is also evident that by incorporating a large amount of polycyclic structures derived from the raw material rosin acid, the pigment dispersibility can be improved, and excellent glossiness can be achieved in the printed matter.