Metal-printing ink composition and printed metal sheet obtained using same

Abstract

Provided is a metal-printing ink composition which comprises an alkyd resin, a pigment, and solvents, wherein the alkyd resin is a resin which cures through oxidative polymerization and the solvents comprise a solvent A and a solvent B. The solvent A is an α-olefin having 14-18 carbon atoms, the solvent B is an alcohol having 10-20 carbon atoms, the total content of the solvent A and the solvent B is 50-100 mass% with respect to the total content of the solvents, and the blending ratio (mass ratio) of the solvent A to the solvent B is 20 / 80 to 80 / 20.

Description

Metallic printing ink composition and printed metal plate using same

[0001] The present disclosure relates to a metallic printing ink composition that reduces the amount of mineral oil solvent used in the field of metallic printing inks, particularly in printing inks used for art cans, three-piece beverage cans, food cans, etc., and that has excellent printing suitability, such as excellent misting resistance and dampening water suitability, and excellent ink topping properties, and to a printed metal plate using the same.

[0002] Currently, metal printing can be broadly divided into two methods: one in which metal is processed into a cylindrical shape and then printed using letterpress offset printing, and the other in which sheet metal is printed using lithographic offset printing with dampening water and then post-processed.Art cans, three-piece beverage cans, food cans, etc. are mainly printed using lithographic offset printing.Metal printing ink printed using the lithographic offset method can be cured by ultraviolet irradiation or by oxidative polymerization using heat, but for applications requiring processability, the method of heat curing through oxidative polymerization of alkyd resins composed of drying oils and drying oil fatty acids is often used.

[0003] On the other hand, in recent years, various industries and sectors have been working to reduce the environmental impact from various perspectives, with the goal of protecting the global environment. In the case of printing inks, there has been growing concern about the use of mineral oil solvents in inks, given their genotoxicity, mutagenicity, and other effects on the human body.

[0004] However, mineral oil solvents have traditionally been used in inks for printing on metal sheets to improve printability and the performance of the cured film (Patent Documents 1 and 2), but the use of solvents other than mineral oils has led to problems such as poor misting resistance and poor suitability for dampening water, which makes it easy for smearing of the image area. Furthermore, the transferability of the ink of the second plate (ability to build up on the ink of the first plate) during overprinting has been insufficient.

[0005] JP 2011-137098 A Japanese Patent No. 4348977 A

[0006] The present disclosure aims to provide a metallic printing ink that reduces the amount of mineral oil solvent used and has excellent printing suitability, such as excellent misting resistance and dampening water suitability, and excellent ink build-up properties, and a printed metal plate using the same.

[0007] After extensive research, the inventors have discovered that in a metallic printing ink composition containing an alkyd resin, a pigment, and a solvent, by using a resin that undergoes oxidative polymerization of the alkyd resin, and by setting the alpha-olefin, which is the solvent in the ink composition, and the alcohol in a specified ratio, it is possible to reduce the amount of mineral oil solvent used and to achieve excellent printability and suitability for the ink to be applied over the surface.

[0008] That is, the present disclosure relates to a metallic printing ink composition containing an alkyd resin, a pigment, and a solvent, wherein the alkyd resin is a resin that hardens by oxidative polymerization, the solvent includes solvent A and solvent B, solvent A is an α-olefin having 14 to 18 carbon atoms, and solvent B is an alcohol having 10 to 20 carbon atoms, the total content of solvent A and solvent B is 50 to 100 mass% of the total content of the solvents, and the blending ratio (mass ratio) of solvent A to solvent B is 20 / 80 to 80 / 20.

[0009] The present disclosure also relates to the metallic printing ink composition, wherein the proportion of fatty acids constituting the alkyd resin is 30 to 70%.

[0010] The present disclosure also relates to a printed metal plate having an ink layer formed using the metallic printing ink composition on a metal plate or on a metal substrate having a base coat layer provided on the metal plate.

[0011] The present disclosure also relates to a method for producing a printed metal plate, in which the metallic printing ink composition is printed on a metal plate or on a metal substrate having a base coat layer provided on a metal plate.

[0012] According to the present disclosure, it is possible to provide a metallic printing ink composition and printed matter that reduce the amount of mineral oil solvent used, exhibit excellent ink laydown, and exhibit good printability. This is particularly useful for printing inks on art cans, three-piece beverage cans, food cans, etc. The metallic printing ink composition can improve the working environment during printing and reduce the environmental impact.

[0013] Hereinafter, one embodiment of the metallic printing ink composition of the present disclosure will be described. Note that the present disclosure is not limited to the following embodiment and can be practiced with appropriate modifications within the scope of the present disclosure.

[0014] (Metallic Printing Ink Composition) The metallic printing ink composition (hereinafter also referred to as the ink composition) of this embodiment 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 this embodiment functions as a binder component and is a resin whose skeleton is a condensate of a polybasic acid and a polyhydric alcohol and which is modified with a fatty acid or oil. There are no particular limitations on the production method, and known methods such as the transesterification method using oil as a raw material and the fatty acid method using fatty acids as a raw material can be used. By using an alkyd resin that cures by oxidative polymerization, an oxidative polymerization curing type ink with good curing properties can be obtained.

[0016] The proportion of the fatty acid or oil constituting the alkyd resin is preferably 30% by mass or more and 70% by mass or less, more preferably 35% by mass or more and 65% by mass or less, and even more preferably 45% by mass or more and 60% by mass or less. An ink composition containing an alkyd resin having a fatty acid or oil proportion within the above range has an excellent balance of ink fluidity, processability, and coating hardness. The fatty acid or oil preferably has an iodine value of 101 or more, more preferably 110, and even more preferably 120 or more. The upper limit of the iodine value is not particularly limited, but one of 200 or less is usually preferred. The use of a fatty acid or oil having an iodine value of 101 or more enables heat curing by oxidative polymerization. Examples of vegetable oil fatty acid components having an iodine value of 101 or more include linseed oil, tung oil, dehydrated castor oil, soybean oil, safflower oil, linseed oil fatty acids, tung oil fatty acids, dehydrated castor oil fatty acids, soybean oil fatty acids, safflower oil fatty acids, etc., and unsaturated fatty acids such as linoleic acid, linolenic acid, eleostearic acid, and 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 acids, dehydrated castor oil, dehydrated castor oil fatty acids, safflower oil, safflower oil fatty acids, soybean oil, and soybean oil fatty acids are preferred, and linseed oil and linseed oil fatty acids are more preferred.

[0017] Furthermore, a portion of the fatty acids and oils may be replaced with monobasic acids other than fatty acids, such as benzoic acid, pt-butylbenzoic acid, abietic acid, hydrogenated abietic acid, and 12-hydroxystearic acid.

[0018] Examples of polybasic acids 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 himic anhydride; and tribasic acids such as trimellitic anhydride, pyromellitic anhydride, methylcyclohexene tricarboxylic anhydride, and benzophenone tetracarboxylic acid. These polybasic acids may be used alone or in combination. In consideration of the physical properties of the coating film, phthalic anhydride, isophthalic acid, and trimellitic anhydride are preferred.

[0019] The use of tris(2-hydroxyethyl)isocyanurate (hereinafter referred to as THEIC) as the polyhydric alcohol increases the distance between crosslinking points in the resin network structure, thereby increasing the degree of freedom and improving processability by exhibiting 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, and 2-butyl-2-ethyl-1,3-propanediol; trihydric alcohols such as glycerin, trimethylolethane, trimethylolpropane, and tris(2-hydroxyethyl)isocyanurate; and tetrahydric or higher alcohols such as pentaerythritol, dipentaerythritol, diglycerin, ditrimethylolpropane, and 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 to 20,000, more preferably 6,000 to 18,000. The number-average molecular weight (Mn) is preferably 1,500 to 6,000, more preferably 2,000 to 5,000. By having Mw and Mn within the above ranges, the ink composition has appropriate cohesive strength and is likely to obtain sufficient film strength. Furthermore, the viscosity of the alkyd resin is appropriate, making it easy to adjust the ink composition to a predetermined shape and providing excellent printability. In this embodiment, the weight-average molecular weight and number-average molecular weight are values ​​measured by gel permeation chromatography (GPC).

[0022] The viscosity of the alkyd resin is preferably 30 Pa·s or more and 300 Pa·s or less, and more preferably 50 Pa·s or more and 150 Pa·s or less. When the viscosity is within the above range, the ink composition can be easily adjusted to a predetermined shape, exhibits good transferability, and provides excellent ink laying properties. In this embodiment, the viscosity is a value measured using an E-type viscometer (RE80 viscometer, manufactured by Toki Sangyo Co., Ltd.) under conditions of a cone diameter of 14 mm, a cone angle of 3 degrees, a temperature of 25°C, and a rotation speed of 1 to 10 rpm.

[0023] The method for producing an alkyd resin is not particularly limited. For example, known methods can be used to produce an alkyd resin, such as a transesterification method using oil as a raw material or a fatty acid method using fatty acids as a raw material. For example, a reaction vessel equipped with a stirrer, a reflux condenser, and a thermometer is charged with the above-described fatty acid, polybasic acid, and polyhydric alcohol together with an azeotropic solvent such as xylene, and the mixture is heated to 230°C with stirring under a nitrogen atmosphere to carry out an esterification reaction. After confirming that the desired acid value has been reached, the reaction is terminated to obtain an alkyd resin.

[0024] The content of the alkyd resin in the ink composition is adjusted appropriately depending on the type and purpose, but is preferably 20 to 75% by mass, more preferably 30 to 65% by mass. When the alkyd resin content is within the above range, the ink composition exhibits good workability and printability, and is also excellent in film strength and processability.

[0025] Furthermore, conventionally used resins can be mixed with the alkyd resin of the present disclosure. That is, known resins compatible with alkyd resins can be used alone or in combination depending on the required performance, such as printability and coating film properties. Specific examples include rosin-modified phenolic resins, polyester resins, petroleum resins, epoxy resins, ketone resins, rosin-modified maleic acid resins, amino resins, and benzoguanamine resins.

[0026] <Pigment> The pigment of the present embodiment is not particularly limited, and any known inorganic or organic pigment for printing ink can be used alone or in combination.

[0027] The inorganic pigments and organic pigments are preferably those having heat resistance, light resistance, and retort resistance. Inorganic pigments include titanium oxide, silica, carbon black, etc. Organic pigments include phthalocyanine pigments, azo pigments, quinacridone pigments, diketopyrrolopyrrole pigments, quinophthalone pigments, threne pigments, dioxazine pigments, isoindolinone pigments, etc.

[0028] The pigment concentration is adjusted appropriately depending on the type and purpose. For example, the content of titanium oxide, which exhibits a white color, in the ink composition is preferably 10 to 70% by mass, more preferably 20 to 65% by mass, the content of carbon black, which exhibits a black color, is preferably 10 to 50% by mass, more preferably 20 to 40% by mass, and the content of organic pigments is preferably 5 to 50% by mass, more preferably 10 to 40% by mass. By ensuring that the pigment contents are within the above ranges, the ink composition exhibits good coloring power and hiding power, and also exhibits excellent dispersion stability.

[0029] <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, the ink composition of this embodiment can reduce the amount of mineral oil solvent used, and has excellent printability such as excellent misting resistance and dampening water suitability, as well as excellent ink laying properties.

[0030] - α-olefins having 14 to 18 carbon atoms (solvent A) Linear or branched α-olefins having 14 to 18 carbon atoms can be used, and examples include 1-octadecene (C18), 1-hexadecene (C16), and 1-tetradecene (C14). These may be used alone or in combination of two or more. If the carbon number is less than C14, the solvent will tend to dry on the printing roll, resulting in poor on-machine stability. On the other hand, if the carbon number is greater than C18, misting resistance will be poor.

[0031] The content of the α-olefin having 14 to 18 carbon atoms in the ink composition is preferably 2 to 20 mass %, more preferably 3 to 15 mass %. 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 ink laying properties.

[0032] Alcohols with 10 to 20 carbon atoms (solvent B) The alcohols with 10 to 20 carbon atoms are not particularly limited. For example, linear or branched alcohols with 10 to 20 carbon atoms can be used, such as higher alcohols such as isooctadecyl alcohol (C18), 2-hexyldecyl alcohol (C16), tridecanol (C13), dodecyl alcohol (C12), and 1-decanol (C10). These may be used alone or in combination of two or more. If the carbon number is less than C10, the solvent will be more likely to volatilize on the printing roll, resulting in poor on-press stability. On the other hand, if the carbon number is greater than C20, misting resistance will be poor.

[0033] The content of solvent B in the ink composition is preferably 2 to 20% by mass, more preferably 3 to 15% by mass. When the content of solvent B is within the above range, the ink composition exhibits good misting resistance.

[0034] In the ink composition of this embodiment, the total content of solvent A and solvent B is 50 to 100% by mass relative to the total content of the solvents. The total content is preferably 60 to 100% by mass, and more preferably 70 to 100% by mass. By being in this range, the ink composition can have excellent printability, such as misting resistance and dampening water suitability, and excellent suitability for ink laying on top.

[0035] The blending ratio of the solvent A to the solvent B is preferably 20 / 80 to 80 / 20, more preferably 25 / 75 to 75 / 25, even more preferably 30 / 70 to 70 / 30, and even more preferably 35 / 65 to 65 / 35. By having the blending ratio within the above range, excellent printability such as misting resistance and dampening water suitability can be achieved, and excellent suitability for ink laying on top can be obtained.

[0036] The content of the solvent in the ink composition is adjusted appropriately depending on the type and purpose, but is preferably 3 to 40% by mass, more preferably 5 to 30% by mass. By keeping the content of the solvent within the above range, the ratio of alkyd resin to solvent in the ink composition becomes favorable, and the tack value of the ink used for normal printing can be adjusted to the range of 5 to 40.

[0037] <Other Components> The ink composition of this embodiment may contain other components such as additives that are typically added to ink compositions, such as pigment dispersants, driers, waxes, viscosity modifiers, and storage stabilizers.

[0038] Furthermore, finely powdered silica, organic bentonite, etc. may be added to the ink as an auxiliary agent within the scope of the present disclosure. Furthermore, a gel varnish containing a metal chelating agent, a sorbitol compound, etc. may also be used as a printing ink varnish component.

[0039] The dryer is a curing accelerator for curing the oxidative polymerization curing printing ink. Examples of printing ink dryers that can be used in the present disclosure include salts of metals such as cobalt, manganese, lead, iron, and zinc with carboxylic acids such as octylic acid, naphthenic acid, neodecanoic acid, tung oil fatty acid, linseed oil fatty acid, soybean oil fatty acid, and resin acid, i.e., 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.

[0040] Examples of waxes include polyethylene wax, carnauba wax, polyolefin, and solid paraffin, with polyethylene wax being preferred and the average particle size of the wax being preferably 3 to 15 μm. This has the advantage of improving scratch resistance and slipperiness. When wax is included, the wax content is preferably 0.1% by mass or more and 5.0% by mass or less.

[0041] Method for Preparing 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 triple roll mill, a ball mill, a bead mill, or the like.

[0042] The tack value of the ink composition is preferably 9.0 to 40.0. In this embodiment, the tack value refers to the value measured after 60 seconds using a Digital Incometer D-2 (manufactured by Toyo Seiki Seisaku-sho, Ltd.) at a temperature of 30°C and a rotation speed of 400 rpm.

[0043] The metallic printing ink composition of the present disclosure has excellent printability, such as excellent misting resistance and dampening water suitability, as well as excellent ink build-up properties, and can be suitably used as an ink for printing on metal sheets (metal plates).

[0044] Suitable metal sheets for printing the metallic printing ink composition of the present disclosure include, but are not limited to, metal sheets such as stainless steel, aluminum, tin-plated steel, and tin-free steel, or metal substrates with a base coat (primer) layer formed on the metal sheets. Base coat compositions commonly used in metal printing, such as sizing paints and white coatings, can be used to form the base coat layer. A PET film may also be laminated.

[0045] The metallic printing ink composition of the present disclosure can be easily printed on these metal plates by a conventional printing method such as a lithographic offset method using dampening water, a dry offset method, etc. The film thickness of the metallic printing ink composition is optional, but may be, for example, in the range of 0.1 to 6 μm.

[0046] The step of curing the metallic printing ink composition of the present disclosure is preferably heat curing, and although there are no particular limitations on the heating conditions, an oven typically used for metallic printing can be used, and the heating temperature is typically 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 is typically in the range of 3 to 30 minutes.

[0047] The method for coating a substrate according to this embodiment includes the steps of providing a printed layer on the substrate using a metallic printing ink composition, applying an overprint varnish to the printed layer, and then performing a curing treatment. Although a printed metal plate does not necessarily require the application of an overprint varnish, the use of an overprint varnish can provide better coating film properties. When applying the overprint varnish, it is usually preferable to apply it after the metallic printing ink composition of the present disclosure has been heat-cured. However, it is also possible to apply the overprint varnish wet-on-wet and then heat-cure both at the same time.

[0048] The overprint varnish is preferably a thermosetting one, and conventionally known varnishes can be used without any particular limitation. Examples include polyester-melamine-based, polyester-epoxy-melamine-based, and polyester-acrylic-melamine-based varnishes. The overprint varnish may be either aqueous or solvent-based.

[0049] The present disclosure will be described below based on synthesis examples and examples, but the present disclosure is not limited to these examples. In the following, "parts" and "%" all mean "parts by mass" and "% by mass".

[0050] (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 xylol were charged into a four-neck flask equipped with a stirrer, and a reaction was carried out at a temperature of 220°C to 230°C while circulating xylol under a nitrogen stream until the acid value reached 10 mgKOH / g or less. After completion of the reaction, xylol was distilled off at 240°C to obtain alkyd resin (1). The amount of dehydration was 8.3 parts.

[0051] (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 xylol were charged into a four-neck flask equipped with a stirrer, and a reaction was carried out at a temperature of 220°C to 230°C while circulating xylol under a nitrogen stream until the acid value reached 10 mgKOH / g or less. After completion of the reaction, xylol was distilled off at 240°C to obtain alkyd resin (2). The amount of dehydration was 5.7 parts.

[0052] (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 xylol were charged into a four-neck flask equipped with a stirrer, and a reaction was carried out at a temperature of 220°C to 230°C while circulating xylol under a nitrogen stream until the acid value reached 10 mgKOH / g or less. After completion of the reaction, xylol was distilled off at 240°C to obtain alkyd resin (3). The amount of dehydration was 11.7 parts.

[0053] The compositions (parts by mass) and parameters of the alkyd resins (1) to (3) are shown in Table 1.

[0054]

[0055] Using the obtained alkyd resins (1) to (3), metallic printing ink compositions of Examples and Comparative Examples were prepared in the formulations (parts by mass) shown in Table 3. The tack value was set in the range of 13.0 to 17.0. The materials listed 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 Toyocolor 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 ("Linearene 12" manufactured by Idemitsu Kosan Co., Ltd.) α-olefin (C20-C24): Mixture of 1-eicosene, 1-docosene, and 1-tetracosene ("Linearene 2024" manufactured by Idemitsu Kosan Co., Ltd.) Alcohol (C18): Isooctadecanol ("Fine Oxocol 180A" manufactured by Nissan Chemical Co., Ltd.) Alcohol (C16): 2-hexyldecyl alcohol ("Fine Oxocol 1600" manufactured by Nissan Chemical Co., Ltd.) Alcohol (C24): 2-decyltetradecanol ("N-Jecol 240A" manufactured by New Japan Chemical Co., Ltd.) Fatty acid ester (C16): isobutyl laurate ("TOSOLV-LIB" manufactured by Toshin Yushi Co., Ltd.) Additive: polyethylene wax ("CERAFLOUR 929N" manufactured by BYK Japan K.K. and other companies, average particle size 8 μm) Hardener: manganese drier ("Manganese Hexoate 8%" manufactured by Toei Kako Co., Ltd.)

[0056] (Evaluation) The ink compositions of Examples 1 to 8 and Comparative Examples 1 to 7 were evaluated in the following manner, and the results are shown in Table 3.

[0057] (Overlaying Ability) A white ink was prepared, and 0.075 cc was printed on an electrolytic tin-plated steel plate (tin plate) using a 4-split roll of an RI tester. Furthermore, the ink compositions prepared in the Examples and Comparative Examples were printed in the same manner, and the overlaying ability of the ink on the white ink was evaluated visually. ◯: The white ink was almost invisible in the overlapping printed area. Δ: The white ink was slightly visible in the overlapping printed area. ×: The white ink was visible in the overlapping printed area. The composition (parts by mass) of the white ink used in the overlaying ability test is shown in Table 2.

[0058] (Misting Resistance) 2.6 cc of the prepared ink composition was applied to the rotating roller of an ink meter, smoothed evenly, and then rotated at 1,200 rpm for 5 minutes. During this time, a 10 cm square plate was placed under the roller, and the amount of ink splashed onto it was compared. Measurements were performed with the roller kept at 40°C. ◯: The mass of the plate before and after measurement changed by less than 20 mg, which does not pose a problem in production. △: The mass of the plate before and after measurement changed by 20 mg or more but less than 50 mg, which means that the ink is slightly splashed, but the plate can still be used in production. ×: The mass of the plate before and after measurement changed by 50 mg or more, which causes a significant problem in production.

[0059] (Dampening Water Suitability) 20 g of dampening water was added to 10 g of the prepared ink composition and stirred for 2 minutes with a disper, and the dampening water alone was filtered, and the degree of discoloration of the dampening water and the degree of ink remaining on the filter paper were evaluated visually. If the dampening water is discolored or the ink composition is dispersed in the dampening water, staining of non-image areas is likely to occur during printing. ○ and △ are practically acceptable levels. ○: No discoloration or ink residue on the filter paper occurred. △: Slight discoloration and / or slight ink residue on the filter paper occurred. ×: Strong discoloration and / or obvious ink residue on the filter paper occurred.

[0060]

[0061]

[0062] As is clear from Table 3, by using the metallic printing ink composition described in the examples of the present disclosure, it was possible to obtain a metallic printing ink composition that was excellent in misting resistance and dampening water suitability, as well as in ink topping properties, even though the ink composition did not contain a mineral oil solvent.

[0063] Although the present invention has been described with reference to the above-mentioned several embodiments, the present invention is not limited to these several embodiments. Various modifications can be made to the configuration and details of the present invention within the scope of the present invention.

[0064] This disclosure is related to the subject matter described in Japanese Patent Application No. 2023-221447, filed December 27, 2023, the entire disclosure of which is incorporated herein by reference.

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 an alcohol having 10 to 20 carbon atoms, the total content of solvent A and solvent B is 50 to 100% by mass based on the total content of the solvent, and the blending ratio (mass ratio) of solvent A and solvent B is 20 / 80 to 80 / 20. Metal printing ink composition.

2. The metal printing ink composition according to claim 1, wherein the blending ratio (mass ratio) of solvent A and solvent B is 25 / 75 to 75 / 25.

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

4. A printed metal plate having an ink layer formed by using the metal printing ink composition according to any one of claims 1 to 3 on a metal plate or on a metal underfloor plate provided with a base coat layer on the metal plate.

5. A method for manufacturing a printed metal plate, comprising printing the metal printing ink composition according to any one of claims 1 to 3 on a metal plate or on a metal underfloor plate provided with a base coat layer on the metal plate.

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