Metal printing ink composition and printed metal plate using the same

Abstract

An object of the present invention is to provide a metal printing ink composition having excellent printing suitability such as reduced usage amount of mineral oil solvent, excellent anti-misting property and wetting water suitability, and excellent overprinting property of the ink, and a printed metal plate using the same. 【Solution means】In a metal printing ink composition containing an alkyd resin, a pigment, and a solvent, the alkyd resin is a resin that cures by oxidative polymerization, the solvent includes a solvent A and a solvent B, the solvent A is an α-olefin having 14 to 18 carbon atoms, the solvent B is an alcohol having 10 to 20 carbon atoms, and a blending ratio (mass ratio) of the solvent A and the solvent B is 20 / 80 to 80 / 20. A metal printing ink composition characterized by this.

Description

Technical Field

[0001] The present invention relates to a metal printing ink composition having excellent printing suitability such as reduced use amount of mineral oil solvent, excellent anti-misting property and wetting water suitability, and excellent overcoating property in printing inks used in the field of metal printing inks, art cans, three-piece beverage cans, food cans, etc., and a printed metal plate using the same.

Background Art

[0002] Currently, metal printing is roughly classified into two methods: a method of performing printing by the letterpress offset method after processing the metal into a cylindrical shape, and a method of performing post-processing after printing on a sheet-shaped metal plate by the lithographic offset method using wetting water. Art cans, three-piece beverage cans, food cans, etc. are mainly printed by the lithographic offset method. The curing methods of metal printing inks printed by the lithographic offset method include curing by ultraviolet irradiation and oxidative polymerization curing by heating. In applications where processability is required, a method of heat-curing by oxidative polymerization of an alkyd resin composed of a drying oil and a fatty acid of a drying oil is frequently used.

[0003] On the other hand, in recent years, with the goal of global environmental protection, activities to promote reduction of environmental load have been carried out in various industries and sectors from various viewpoints. In printing inks, concerns about the use of mineral oil solvents in inks have been increasing in view of the effects on the human body such as the genotoxicity and mutagenicity of mineral oils.

[0004] However, mineral oil solvents have conventionally been used in inks for metal sheet printing for the purpose of expressing printing suitability and the performance of the cured film (Patent Documents 1 and 2). When solvents other than mineral oil are used, there are problems such as poor anti-misting property and poor suitability for wetting water, so that the lined part is likely to be soiled. Furthermore, the transferability of the second ink when overprinting (the overcoating property on the first ink) was not sufficient.

Prior Art Documents

Patent Documents

[0005] Patent Document 1 Japanese Patent Application Laid-Open No. 2011-137098 Patent Document 2 Japanese Patent No. 4348977 Summary of the Invention Problems to be Solved by the Invention

[0006] An object of the present invention is to provide a metal printing ink having reduced usage amount of mineral oil solvent, excellent printing suitability such as excellent anti-misting property and wetting water suitability, and excellent suitability for ink overcoating property, and a printed metal plate using the same. Means for Solving the Problems

[0007] As a result of intensive studies, the present inventors have found that in a metal printing ink composition containing an alkyd resin, a pigment, and a solvent, by using a resin in which the alkyd resin undergoes oxidative polymerization and setting a predetermined ratio of an α-olefin, which is a solvent in the ink composition, and an alcohol, the usage amount of the mineral oil solvent can be reduced, and excellent printing suitability and suitability for ink overcoating property can be exhibited.

[0008] That is, the present invention is a metal printing ink composition containing an alkyd resin, a pigment, and a solvent, wherein the alkyd resin is a resin that cures by oxidative polymerization, the solvent includes a Solvent A and a Solvent B, the Solvent A is an α-olefin having 14 to 18 carbon atoms, the Solvent B is an alcohol having 10 to 20 carbon atoms, a blending ratio (mass ratio) of the Solvent A to the Solvent B is 20 / 80 to 80 / 20, relating to an ink composition for metal printing.

[0009] Further, the present invention relates to the metal printing ink composition, wherein a ratio of a fatty acid constituting the alkyd resin is 30 to 70%.

[0010] Furthermore, the present invention relates to a printed metal plate having an ink layer formed using the metal printing ink composition on a metal plate or on a metal underfloor plate provided with a base coat layer on the metal plate.

[0011] The present invention also relates to a method for manufacturing a printed metal plate, which comprises printing the metal printing ink composition on a metal plate or on a metal underfloor plate provided with a base coat layer on the metal plate.

Advantages of the Invention

[0012] According to the present invention, it is possible to provide a metal printing ink composition and a printed matter that reduce the amount of mineral oil solvent used, exhibit excellent overprintability of ink, and show good printing suitability. In particular, it is useful for printing inks for art cans, three-piece beverage cans, food cans, etc. The above metal printing ink composition can improve the working environment during printing and reduce the environmental load.

Embodiments for Carrying Out the Invention

[0013] Hereinafter, an embodiment of the metal printing ink composition of the present invention will be described. It should be noted that the present invention is not limited to the following embodiments, and can be implemented with appropriate modifications within the scope of the present invention.

[0014] (Printing Ink Composition for Metals) The metal printing ink composition of the present embodiment (hereinafter also referred to as the ink composition) contains an alkyd resin, a pigment, and a solvent as essential components. Each component will be described below.

[0015] <Alkyd Resin> The alkyd resin of the present embodiment functions as a binder component, and is a resin having a condensate of a polybasic acid and a polyhydric alcohol as a skeleton and modified with a fatty acid or an oil. The production method thereof is not particularly limited, and known methods such as a transesterification method using oil as a raw material and a fatty acid method using fatty acid as a raw material can be used.

[0016] The proportion of fatty acids or oils constituting the alkyd resin is preferably 30% by mass or more and 70% by mass or less in the alkyd resin, more preferably 35% by mass or more and 65% by mass or less, and still more preferably 45% by mass or more and 60% by mass or less. An ink composition containing an alkyd resin in which the proportion of fatty acids or oils is within the above range is excellent in the balance of ink fluidity, processability, and coating film hardness. As the fatty acid or oil, a fatty acid or oil having an iodine value of 101 or more is preferable. More preferably 110, and still more preferably 120 or more. The upper limit value of the iodine value is not particularly limited, but those usually having 200 or less are preferably used. By using a fatty acid or oil having an iodine value of 101 or more, heat curing by oxidative polymerization becomes possible. Examples of the vegetable oil fatty acid component having an iodine value of 101 or more include linseed oil, tung oil, dehydrated castor oil, soybean oil, safflower oil, linseed oil fatty acid, tung oil fatty acid, dehydrated castor oil fatty acid, soybean oil fatty acid, safflower oil fatty acid, etc., and unsaturated fatty acids such as linoleic acid, linolenic acid, eleostearic acid or ricinoleic acid. These can be used alone or in combination of two or more. Considering the physical properties of the coating film, linseed oil, linseed oil fatty acid, dehydrated castor oil, dehydrated castor oil fatty acid, safflower oil, safflower oil fatty acid, soybean oil, soybean oil fatty acid are preferable, and linseed oil, linseed oil fatty acid are more preferable.

[0017] Also, part of the fatty acid or oil may be changed to a monobasic acid other than the fatty acid. As other monobasic acids, benzoic acid, p-t-butylbenzoic acid, abietic acid, hydrogenated abietic acid, 12-hydroxystearic acid, etc. can be used.

[0018] Examples of the polybasic acid include aromatic dibasic acids such as phthalic anhydride, isophthalic acid, terephthalic acid, 2,6-naphthalenedicarboxylic acid, and 5-sodium sulfoisophthalic acid; alicyclic dibasic acids such as tetrahydrophthalic anhydride, hexahydrophthalic anhydride, and 1,4-cyclohexanedicarboxylic acid; aliphatic dibasic acids such as succinic anhydride, alkenyl succinic anhydride, fumaric acid, maleic anhydride, itaconic acid, adipic acid, sebacic acid, azelaic acid, and hymic anhydride; and tribasic acids such as trimellitic anhydride, pyromellitic anhydride, methylcyclohexenetricarboxylic anhydride, and benzophenonetetracarboxylic acid. These polybasic acids may be used alone or in combination of two or more. Considering the physical properties of the coating film, phthalic anhydride, isophthalic acid, and trimellitic anhydride are preferred.

[0019] By using tris(2-hydroxyethyl)isocyanurate (hereinafter referred to as THEIC) as the polyhydric alcohol, the crosslinking point distance of the resin network structure becomes longer, increasing the degree of freedom, and improving the processability by expressing flexibility. The proportion of THEIC in the polyhydric alcohol component constituting the alkyd resin is preferably 15% by mass or more.

[0020] Examples of polyhydric alcohols other than THEIC include dihydric alcohols such as ethylene glycol, propylene glycol, 1,3 - butanediol, 1,4 - butanediol, 1,5 - pentanediol, 1,6 - hexanediol, 1,9 - nonanediol, 2 - methyl - 1,8 - octanediol, neopentyl glycol, diethylene glycol, triethylene glycol, dipropylene glycol, tripropylene glycol, tetramethylene glycol, 1,4 - cyclohexanediol, 1,4 - cyclohexanedimethanol, bisphenol A, hydrogenated bisphenol A, 2 - butyl - 2 - ethyl - 1,3 - propanediol; trihydric alcohols such as glycerin, trimethylolethane, trimethylolpropane, tris(2 - hydroxyethyl) isocyanurate; and polyhydric alcohols with a valency of 4 or more such as pentaerythritol, dipentaerythritol, diglycerin, ditrimethylolpropane, ditrimethylolethane. These polyhydric alcohols may be used alone or in combination of two or more.

[0021] The styrene - equivalent weight - average molecular weight (Mw) of the alkyd resin is preferably 5,000 or more and 20,000 or less, more preferably 7,000 or more and 18,000 or less. Also, the number - average molecular weight (Mn) is preferably 1,500 or more and 6,000 or less, more preferably 2,000 or more and 5,000 or less. When Mw and Mn are within the above ranges, the ink composition has appropriate cohesive force, and sufficient film strength is easily obtained. Also, the viscosity of the alkyd resin becomes appropriate, the ink composition is easily adjusted to a predetermined shape, and it has excellent printing suitability. In this embodiment, the weight - average molecular weight and the number - average molecular weight are values measured by gel permeation chromatography (GPC).

[0022] The method for producing the alkyd resin is not particularly limited. For example, as the method for producing the alkyd resin, known methods such as a transesterification method using oil as a raw material and a fatty acid method using fatty acid as a raw material can be used. As an example, the above-described fatty acid, polybasic acid, and polyhydric alcohol are charged into a reaction vessel equipped with a stirrer, a reflux condenser, and a thermometer together with an azeotropic solvent such as xylene, and the temperature is raised to 230 ° C with stirring in a nitrogen atmosphere to carry out an esterification reaction. Then, after confirming that the acid value is arbitrary, the reaction is terminated to obtain an alkyd resin.

[0023] The content of the alkyd resin in the ink composition is appropriately adjusted depending on the type and purpose, but is preferably 20 to 75% by mass, and more preferably 30 to 65% by mass. When the content of the alkyd resin is within the above range, the ink composition exhibits good workability and printing suitability, and is also excellent in film strength and processability.

[0024] Furthermore, the conventionally used resin can also be mixed with the alkyd resin of the present invention and used. That is, depending on the required performance such as printing suitability and coating film physical properties, a known resin compatible with the alkyd resin can be used alone or in combination of a plurality. Specifically, for example, rosin-modified phenolic resin, polyester resin, petroleum resin, epoxy resin, ketone resin, rosin-modified maleic acid resin, amino resin, benzoguanamine resin, etc. can be exemplified.

[0025] <Pigment> The pigment of the present embodiment is not particularly limited. Known inorganic pigments or organic pigments for printing inks can be used alone or in combination of a plurality.

[0026] The inorganic pigment and the organic pigment preferably have heat resistance, light resistance, and retort processability. Examples of the inorganic pigment include titanium oxide, silica, carbon black, etc. Examples of the organic pigment include phthalocyanine-based pigments, azo-based pigments, quinacridone-based pigments, diketopyrrolopyrrole-based pigments, quinophthalone-based pigments, perylene-based pigments, dioxazine-based pigments, isoindolinone-based pigments, etc.

[0027] The pigment concentration is appropriately adjusted according to the type and purpose. For example, titanium oxide showing white color is preferably 10 to 70% by mass, more preferably 20 to 65% by mass in the ink composition, carbon black showing black color is preferably 10 to 50% by mass, more preferably 20 to 40% by mass, and the organic pigment is preferably 5 to 50% by mass, more preferably 10 to 40%. When the content of the pigment is within the above range, the ink composition exhibits good coloring power and hiding power, and also has excellent dispersion stability.

[0028] <Solvent> The solvent contains an α-olefin having 14 to 18 carbon atoms (solvent A) and an alcohol having 10 to 20 carbon atoms (solvent B). By blending these solvents in the ink composition of the present embodiment, the amount of the mineral oil solvent used can be reduced, and the ink composition has excellent printing suitability such as anti-misting property and wetting water suitability, and excellent additional properties of the ink.

[0029] ·α-olefin having 14 to 18 carbon atoms (solvent A) As the α-olefin having 14 to 18 carbon atoms, a linear or branched one can be used, and examples thereof include 1-octadecene (C18), 1-hexadecene (C16), 1-tetradecene (C14), etc. These may be used alone or in combination of two or more. If the carbon number is less than C14, the solvent is likely to dry on the printing roll, resulting in poor in-machine stability. On the other hand, if the carbon number is greater than C18, the anti-misting property deteriorates.

[0030] The content of the α-olefin having 14 to 18 carbon atoms is preferably 2 to 20% by mass, more preferably 3 to 15% by mass in the ink composition. When the content of the α-olefin having 14 to 18 carbon atoms is within the above range, the ink composition exhibits good transferability and excellent additional properties of the ink.

[0031] ·Alcohol having 10 to 20 carbon atoms (solvent B) Alcohols having 10 to 20 carbon atoms are not particularly limited. For example, linear or branched alcohols having 10 to 20 carbon atoms can be used, and they are higher alcohols such as isooctadecyl alcohol (C18), tridecanol (C13), dodecyl alcohol (C12), 1-decanol (C10), etc. These can be used alone or in combination of two or more. If the carbon number is less than C10, the solvent is likely to volatilize on the printing roll, resulting in poor in-air stability. On the other hand, if the carbon number is greater than C20, the anti-misting property deteriorates.

[0032] The content of Solvent B is preferably 2 to 20% by mass, more preferably 3 to 15% by mass in the ink composition. When the content of Solvent B is within the above range, the ink composition exhibits good anti-misting property.

[0033] The mixing ratio of the Solvent A and the Solvent B is preferably 20 / 80 to 80 / 20, more preferably 30 / 70 to 70 / 30. When the mixing ratio is within the above range, it has excellent printing suitability in terms of anti-misting property and wetting water suitability, and can have excellent suitability in the overprinting property of the ink.

[0034] The content of the solvent in the ink composition is appropriately adjusted according to the type and purpose, but is preferably 3 to 40% by mass, more preferably 5 to 30% by mass. When the content of the solvent is within the above range, the ratio of the alkyd resin and the solvent in the ink composition becomes good, and the tack value of the ink for normal printing can be adjusted to the range of 5 to 40.

[0035] <Other Components> Additives usually blended in the ink composition can be blended as other components in the ink composition of the present embodiment. For example, pigment dispersants, driers, waxes, viscosity modifiers, storage stabilizers, etc. can be mentioned.

[0036] Also, within a range not impairing the object of the present invention, fine powder silica, organic bentonite, etc. may be added to the ink as an auxiliary agent. Also, as a varnish component for printing ink, it is possible to use a gel varnish made of a metal chelating agent, a sorbitol compound, or the like.

[0037] A dryer is a curing accelerator for curing an oxidation polymerization-curing type printing ink. Examples of the dryer for printing ink that can be used in the present invention include salts of metals such as cobalt, manganese, lead, iron, zinc, etc. and carboxylic acids such as octylic acid, naphthenic acid, neodecanoic acid, tung oil fatty acid, linseed oil fatty acid, soybean oil fatty acid, resin acid, etc., that is, metal soaps. These can be used alone or in combination of two or more. When a dryer is included, the content of the dryer is preferably 0.002% by mass or more and 5.0% by mass or less.

[0038] Examples of the wax include polyethylene wax, carnauba wax, polyolefin, solid paraffin, etc., polyethylene wax is preferable, and the average particle diameter of the wax is preferably 3 to 15 μm. Thereby, there is an advantage that the scratch resistance and the slipperiness are improved. When the wax is included, the content of the wax is preferably 0.1% by mass or more and 5.0% by mass or less.

[0039] · Method for adjusting printing ink The method for preparing the ink composition of the present embodiment is not particularly limited. For example, the ink composition can be prepared by a conventional method using a three-roll mill, a ball mill, a bead mill, etc.

[0040] The tack value of the ink composition is preferably 9.0 to 40.0. In the present embodiment, the tack value refers to the measured value 60 seconds after measurement when using a digital inkometer D-2 (manufactured by Toyo Seiki Seisakusho Co., Ltd.) at a temperature of 30 ° C and a rotation speed of 400 rpm.

[0041] The metal printing ink composition of the present invention has excellent printing suitability such as excellent anti-misting property and wetting water suitability, and excellent suitability as an overprinting property of the ink, and can be suitably used as an ink for printing on a metal sheet (metal plate).

[0042] As the metal plate for printing the metal printing ink composition of the present invention, a metal plate such as stainless steel, aluminum, tin-plated steel sheet, tin-free steel, or a metal underfloor plate provided with a base coat (primer) layer on these metal plates is preferable, but it is not limited thereto. For forming the base coat layer, for example, a composition for base coat such as a sizing paint or a white coating generally used in metal printing can be used. Also, the PET film may be laminated.

[0043] The metal printing ink composition of the present invention can be easily printed on these metal plates by a normal printing method such as a lithographic offset method or a dry offset method using wetting water. The film thickness of the metal printing ink composition is arbitrary, but for example, it may be in the range of 0.1 to 6 μm.

[0044] The step of performing the curing treatment on the metal printing ink composition of the present invention is preferably heat curing. The heating conditions are not particularly limited, but an oven usually used for metal printing can be used, and the heating temperature is usually in the range of 120 to 230°C. The heating time is not particularly limited as long as it is 3 minutes or more, but it is usually in the range of 3 to 30 minutes.

[0045] The coating method of the base material in this embodiment includes a step of providing a printed layer on the base material with a metal printing ink composition, a step of applying an overprint varnish on the printed layer, and then a step of performing a curing treatment. The printed metal plate does not necessarily require the application of an overprint varnish, but by using an overprint varnish, better coating film physical properties can be obtained. When applying the overprint varnish, usually, it is preferably performed after heat-curing the metal printing ink composition of the present invention. However, it is also possible to cure both simultaneously after overcoating in a wet-on-wet manner.

[0046] The overprint varnish is preferably a thermosetting one, and conventionally known ones can be used without particular limitation. For example, polyester-melamine-based, polyester-epoxy-melamine-based, polyester-acrylic-melamine-based varnishes, etc. can be exemplified. Also, the overprint varnish may be either an aqueous type or a solvent type.

Examples

[0047] The present invention will be described below based on synthesis examples, examples, etc., but the present invention is not limited only to these examples. In the following, both "parts" and "%" are "parts by mass" and "mass%", respectively.

[0048] (Alkyd resin (1)) 50 parts of linseed oil fatty acid, 23.4 parts of isophthalic acid, 19.4 parts of THEIC, 15.2 parts of trimethylolpropane, and 10 parts of xylene were charged into a four-necked flask equipped with a stirrer, and the reaction was carried out at a temperature of 220°C to 230°C while refluxing xylene under a nitrogen stream until the acid value reached 10 mgKOH / g or less. After the reaction was completed, xylene was distilled off at 240°C to obtain alkyd resin (1). The amount of water removed was 8.3 parts.

[0049] (Alkyd resin (2)) 40 parts of dehydrated castor oil fatty acid, 25.6 parts of phthalic anhydride, 26.5 parts of THEIC, 13.6 parts of trimethylolpropane, and 10 parts of xylene were charged into a four-necked flask equipped with a stirrer. While refluxing xylene under a nitrogen stream, the reaction was carried out at a temperature of 220°C to 230°C until the acid value reached 10 mgKOH / g or less. After the reaction was completed, xylene was distilled off at 240°C to obtain alkyd resin (2). The amount of water removed was 5.7 parts.

[0050] (Alkyd resin (3)) 60 parts of linseed oil fatty acid, 14.6 parts of isophthalic acid, 33.1 parts of THEIC, 4 parts of pentaerythritol, and 10 parts of xylene were charged into a four-necked flask equipped with a stirrer. While refluxing xylene under a nitrogen stream, the reaction was carried out at a temperature of 220°C to 230°C until the acid value reached 10 mgKOH / g or less. After the reaction was completed, xylene was distilled off at 240°C to obtain alkyd resin (3). The amount of water removed was 11.7 parts.

[0051] The compositions and parameters of alkyd resins (1) to (3) are shown in Table 1.

[0052]

Table 1

[0053] Using the obtained alkyd resins (1) to (3), the metal printing ink compositions of the examples and comparative examples were adjusted with the formulations shown in Table 3. The tack value was set in the range of 13.0 to 17.0. The materials described in the table are shown below. The numbers in parentheses indicate the number of carbon atoms. · Pigment: Phthalocyanine Blue 15:3 (“LIONOL BLUE FG-7351” manufactured by Toyo Color Co., Ltd.) · α-olefin (C18): 1-octadecene (“Linearene 18” manufactured by Idemitsu Kosan Co., Ltd.) · α-olefin (C16): 1-hexadecene (“Linearene 16” manufactured by Idemitsu Kosan Co., Ltd.) · α-olefin (C12): 1-dodecene ("Linen 12" manufactured by Idemitsu Kosan Co., Ltd.) · α-olefin (C20-C24): mixture of 1-eicosene, 1-docosene, and 1-tetracosene ("Linen 2024" manufactured by Idemitsu Kosan Co., Ltd.) · Alcohol (C18): isooctadecanol ("Fine Oxocol 180A" manufactured by Nissan Chemical Industries, Ltd.) · Alcohol (C16): 2-hexyldecyl alcohol ("Fine Oxocol 1600" manufactured by Nissan Chemical Industries, Ltd.) · Alcohol (C24): 2-decyltetradecanol ("NJE Col 240A" manufactured by Nippon Rika Kogyo Co., Ltd.) · Fatty acid ester (C16): isobutyl laurate ("TOSOLV-LIB" manufactured by ToShin Oil & Fat Co., Ltd.) · Additive: polyethylene wax ("CERAFLOUR 929N" manufactured by BYK-Chemie Japan Co., Ltd., average particle diameter 8 μm) · Hardening agent: manganese drier ("Manganese 8% Hexoate" manufactured by Toei Chemical Industry Co., Ltd.)

[0054] (Evaluation) The ink compositions of Examples 1 to 7 and Comparative Examples 1 to 7 were evaluated as follows, and the results are shown in Table 3.

[0055] (Overprintability) White ink was prepared, and 0.075 cc was printed on an electrolytic tin-plated steel sheet (tin plate) with a 4-division roll of an RI tester. Further, the ink compositions prepared in the examples and comparative examples were printed in the same manner, and the overprintability of the ink on the white ink was visually evaluated. 〇: Almost no white ink is visible in the overprinted part. △: The white ink is slightly visible through the overprinted part. ×: The white ink is visible through the overprinted part. The composition of the white ink used in the overprintability test is shown in Table 2.

Table 2

[0056] (Misting resistance) Take 2.6 cc of the adjusted ink composition and apply it to the rotating roller of the inkometer. After leveling it uniformly, rotate it at 1,200 rpm for 5 minutes. During this time, place a 10 cm square plate under the roller and compare the amount of ink splashed onto it. The measurement was carried out with the roller maintained at 40°C. 〇: The mass change of the plate before and after measurement is less than 20 mg, which does not pose a problem during production. △: The mass change of the plate before and after measurement is 20 mg or more and less than 50 mg. The ink is slightly splashing, but it can be used in production. ×: The mass change of the plate before and after measurement is 50 mg or more, which greatly hinders production.

[0057] (Dampening water suitability) Add 20 g of dampening water to 10 g of the adjusted ink composition and stir with a disper for 2 minutes. Filter only the dampening water, and visually evaluate the degree of coloring of the dampening water and the degree of ink remaining on the filter paper. If the dampening water is colored or the ink composition is dispersed in the dampening water, dirt on non-printing areas is likely to occur during printing. ○ and △ are at a practical level. 〇: No coloring and no ink remaining on the filter paper have occurred. △: Slight coloring and / or slight ink remaining on the filter paper have occurred. ×: Strong coloring and / or obvious ink remaining on the filter paper have occurred.

[0058]

Table 3

[0059] As is clear from Table 3, by using the metal printing ink composition described in the examples of the present invention, even in an ink composition containing no mineral oil solvent, a metal printing ink composition excellent in misting resistance, dampening water suitability, and ink overprinting properties could be obtained.

Claims

1. A metal printing ink composition containing an alkyd resin, a pigment, and a solvent, wherein the alkyd resin is a resin that cures by oxidative polymerization, the solvent includes Solvent A and Solvent B, Solvent A is an α-olefin having 14 to 18 carbon atoms, Solvent B is a linear or branched alcohol having 10 to 20 carbon atoms, and the content of Solvent A is 4% by mass or more in the ink composition, the content of Solvent B is 3% by mass or more in the ink composition, and the blending ratio (mass ratio) of Solvent A to Solvent B is 20 / 80 to 80 / 20, A metal printing ink composition.

2. The metal printing ink composition according to Claim 1, wherein the blending ratio (mass ratio) of Solvent A to Solvent B is 30 / 70 to 70 / 30.

3. The metal printing ink composition according to Claim 1, wherein the proportion of tris(2-hydroxyethyl) isocyanurate in the polyhydric alcohol component constituting the alkyd resin is 15% by mass or more.

4. The metal printing ink composition according to Claim 1, wherein the proportion of the fatty acid constituting the alkyd resin is 30 to 70%.

5. A printed metal plate having an ink layer formed by using the metal printing ink composition according to any one of Claims 1 to 4 on a metal plate or on a metal underlayer plate provided with a base coat layer on the metal plate.

6. A method for manufacturing a printed metal plate, comprising printing the metal printing ink composition according to any one of Claims 1 to 4 on a metal plate or on a metal underlayer plate provided with a base coat layer on the metal plate.

7. A method for manufacturing a printed metal plate, comprising printing the metal printing ink composition according to any one of Claims 1 to 4 on a metal plate or on a metal underlayer plate provided with a base coat layer on the metal plate, and performing heat curing at 120 to 230°C for 3 to 30 minutes.

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