Gravure or flexographic ink, printed material, and laminate

Abstract

To provide a gravure or flexographic ink that is superior in temporal stability, blocking resistance, high-temperature laminate strength, and low residual solvent level.SOLUTION: A gravure or flexographic ink includes a urethane resin (A), wherein the breaking stress of the urethane resin (A), measured under the conditions defined below, is 10 MPa or more, and the viscosity of the urethane resin (A) at a liquid temperature of 25°C and a solid content of 30 mass%, measured in accordance with JIS K 7117-1, is 800 mPa s or more. (Stress measurement conditions) Tensile speed: 50 mm / min, Temperature: 25°C, Sample shape: thickness 0.3 mm, width 5 mm, length 20 mm.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to gravure or flexographic inks, printed matter, and laminates.

Background Art

[0002] When using a transparent substrate such as an OPP film, a PET film, an NY film, or a metal oxide vapor-deposited film thereof as the substrate of a packaging material, printing using printing ink is performed for decorating or surface protecting the substrate. The printed substrate then undergoes a slitting process and is sent to a laminating process, and finally becomes a package for food packaging, cosmetic packaging, and other various applications.

[0003] The characteristics required for laminating printing ink include not only color characteristics that exhibit sufficient beauty, but also plate clogging resistance, adhesion to the film, sufficient lamination strength, blocking resistance that prevents the ink from being taken to the back surface of the film substrate when printed and wound up, and that residual components (residual solvents, etc.) contained in the printed layer formed from the printing ink do not affect the taste and odor of the contents of the food package. In particular, blocking resistance and lamination strength are important among various printing physical properties, and due to the diversification of packaging materials and work process efficiency in recent years, the required performance has become more stringent.

[0004] For example, Patent Document 1 discloses an ink containing a urethane resin having a viscosity of 1700 cP (25°C), and Patent Document 2 discloses an ink containing a urethane resin having a viscosity of 2230 mPa·S (25°C), but in both cases, the hardness of the urethane resin was not sufficient and there was a problem with blocking resistance. Furthermore, Patent Document 3 discloses an ink containing a urethane having a breaking strength of 19 MPa, but there was room for improvement in stability over time and blocking resistance.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0006] An object of the present invention is to provide a gravure or flexographic ink that is excellent in stability over time, blocking resistance, and high-temperature lamination strength and has a low residual solvent content.

[0007] As a result of intensive studies on the above problems, the present inventors have found that the above problems can be solved by using the gravure or flexographic ink described below, and have thus completed the present invention.

[0008] That is, the present invention relates to the following [1] to

[12] .

[0009] [1] A gravure or flexographic ink containing a urethane resin (A), wherein the stress at break of the urethane resin (A) measured under the following conditions is 10 MPa or more, A gravure or flexographic ink, wherein the viscosity of the urethane resin (A) measured according to JIS K 7117-1 at a liquid temperature of 25°C and a solid content of 30% by mass is 800 mPa·s or more. (Stress Measurement Conditions) Tensile speed: 50 mm / min, Temperature: 25°C Sample shape: Thickness 0.3 mm, Width 5 mm, Length 20 mm

[0010] [2] A gravure or flexographic ink containing a urethane resin (A), wherein the total of the urethane bond concentration and the urea bond concentration of the urethane resin (A) is 2.2 to 4 mmol / g, The gravure or flexographic ink, wherein the urethane resin (A) has a viscosity of 800 mPa·s or more as measured according to JIS K 7117-1 at a liquid temperature of 25°C and a solid content of 30% by mass.

[0011] [3] The gravure or flexographic ink according to [1] or [2], wherein the elongation at break of the urethane resin (A) measured under the following conditions is 500% or more. (Elongation measurement conditions) Tensile speed: 50 mm / min, Temperature: 25°C Sample shape: Thickness 0.3 mm, Width 5 mm, Length 20 mm

[0012] [4] The gravure or flexographic ink according to any one of [1] to [3], wherein the urethane resin (A) contains an aromatic isocyanate-derived structure.

[0013] [5] The gravure or flexographic ink according to any one of [1] to [4], wherein the urethane resin (A) contains a polyester-derived structure and / or a polyether-derived structure.

[0014] [6] The gravure or flexographic ink according to any one of [1], [3] to [5], wherein the total of the urethane bond concentration and the urea bond concentration of the urethane resin (A) is 2.2 to 4.0 mmol / g.

[0015] [7] The gravure or flexographic ink according to any one of [1] to [6], wherein the urethane resin (A) contains a urethane resin (a1) having an acid value of less than 1 mgKOH / g.

[0016] [8] The gravure or flexographic ink according to [7], wherein the urethane resin (A) further contains a urethane resin (a2) having an acid value of 1 mgKOH / g or more.

[0017] [9] The gravure or flexographic ink according to [8], wherein the mass ratio of the urethane resin (a1) to the urethane resin (a2) is 9.9:0.1 to 2:8.

[0018]

[10] Furthermore, the gravure or flexographic ink according to any one of [1] to [9], which contains at least one selected from the group consisting of a vinyl chloride resin, a vinyl acetal resin, and a cellulose resin.

[0019]

[11] A printed matter having a printing layer made of the gravure or flexographic ink according to any one of [1] to

[10] on a substrate 1.

[0020]

[12] A laminate having a printing layer made of the gravure or flexographic ink according to any one of [1] to

[10] on a substrate 1. [Effects of the Invention]

[0021] According to the present invention, it is possible to provide a gravure or flexographic ink that is excellent in stability over time, blocking resistance, and high-temperature lamination strength and has a small amount of residual solvent. [Embodiments for Carrying Out the Invention]

[0022] Hereinafter, embodiments of the present invention will be described in detail. However, the present invention is not limited to the embodiments described below, and various embodiments can be taken without departing from the gist of the present invention. Hereinafter, the gravure or flexographic ink may be simply referred to as "ink".

[0023] [Gravure or Flexographic Ink] The present invention is a gravure or flexographic ink containing a urethane resin (A), wherein the stress at break of the urethane resin (A) is 10 MPa or more, and the viscosity measured according to JIS K 7117-1 at a liquid temperature of 25°C and a solid content of 30% by mass of the urethane resin (A) is 800 mPa·s or more.

[0024] Further, in the present invention, the total of the urethane bond concentration and the urea bond concentration of the urethane resin (A) is 2.2 to 4.0 mmol / g, and the viscosity measured according to JIS K 7117-1 at a liquid temperature of 25°C and a solid content of 30% by mass of the urethane resin (A) is 800 mPa·s or more.

[0025] When the stress at break of the urethane resin (A) is 10 MPa or more, or the total of the urethane bond concentration and the urea bond concentration is 2.2 to 4.0 mmol / g, the strength of the molecular chains in the urethane resin (A) is improved. Further, when the viscosity measured according to JIS K 7117-1 at a liquid temperature of 25°C and a solid content of 30% by mass of the urethane resin (A) is 800 mPa·s or more, the molecular chains of the urethane resin (A) spread into the solution, and the entanglement between the molecular chains increases. By combining the above effects, a tough coating film can be formed by forming a molecular chain network in which hard molecular chains are intricately entangled. Further, when the ink of the present invention contains a pigment, the above molecular chain network can capture the pigment, thereby suppressing re-aggregation and sedimentation of the pigment. Due to these characteristics, the ink of the present invention is excellent in storage stability, blocking resistance, and high-temperature lamination strength, and can reduce the amount of residual solvent.

[0026] <Embodiment Satisfying the Requirement of the Stress at Break of the Urethane Resin (A)> In one embodiment satisfying the requirement of the stress at break of the above-mentioned urethane resin (A), the acid value of the urethane resin (A) is preferably less than 1 mgKOH / g, the amine value is preferably 0.3 to 15 mgKOH / g, the hydroxyl value is preferably 0 to 3 mgKOH / g, the weight average molecular weight is preferably 10,000 to 200,000, the glass transition temperature is preferably -30 to 20°C, the urethane bond concentration is preferably 0.6 to 3.6 mmol / g, the urea bond concentration is preferably 0.4 to 1.8 mmol / g, and the total of the urethane bond concentration and the urea bond concentration is preferably 2.2 to 4.0 mmol / g.

[0027] In the above-described embodiment, as the polyol constituting the urethane resin (A), various known polyester polyols, polyether polyols, polycarbonate polyols, polycaprolactone diols, polyolefin polyols, castor oil polyols, hydrogenated castor oil polyols, etc. can be used. The mass ratio of the polyester polyol to the polyether polyol in the polyol constituting the urethane resin (A) is preferably 50:50 to 99:1.

[0028] In the above-described embodiment, the polyol constituting the urethane resin (A) preferably contains a diol. Specific examples of the diol include linear diols such as ethylene glycol, propylene glycol, butylene glycol, diethylene glycol, triethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,6-hexanediol, 1,8-octanediol, 1,9-nonanediol; branched diols such as 1,2-propanediol, neopentyl glycol, 3-methyl-1,5-pentanediol, 2,4-diethyl-1,5-pentanediol, butylethylpropanediol, methylnonanediol; alicyclic diols such as cyclohexanedimethanol and cyclohexanediol. These may be used alone or in combination of two or more. Among them, aliphatic diols having an alkyl group with 1 to 6 carbon atoms as a substituent are preferred, and more specifically, one or more selected from the group consisting of 3-methyl-1,5-pentanediol, 2,4-diethyl-1,5-pentanediol, butylethylpropanediol, 2-methyl-1,3-propanediol, and neopentyl glycol are preferred.

[0029] In the above-described embodiment, examples of the polyisocyanate constituting the urethane resin (A) include aromatic diisocyanates such as tolylene diisocyanate, aliphatic diisocyanates such as hexamethylene diisocyanate, alicyclic diisocyanates such as isophorone diisocyanate, and dimer diisocyanates obtained by converting the carboxyl groups of dimer acids into isocyanate groups. Among them, aromatic isocyanate and / or alicyclic isocyanate are preferably used, and aromatic isocyanate is more preferably used. As the aromatic isocyanate, tolylene diisocyanate, 2,4-tolylene diisocyanate, and 2,6-tolylene diisocyanate are preferably used, and tolylene diisocyanate is more preferably used. Further, in the above-described embodiment, it is preferable that the aromatic isocyanate-derived structure is contained in an amount of 50% by mass or more in 100% by mass of the polyisocyanate-derived structure of the urethane resin (A).

[0030] As a more preferable embodiment for satisfying the requirement for the stress at break of the above-described urethane resin (A), in the urethane resin (A), the weight average molecular weight is 10,000 to 200,000, the total of the urethane bond concentration and the urea bond concentration is 2.2 to 4.0 mmol / g, the mass ratio of the polyester polyol and the polyether polyol constituting the urethane resin (A) is 50:50 to 99:1, the polyisocyanate constituting the urethane resin (A) is an aromatic isocyanate such as tolylene diisocyanate, 2,4-tolylene diisocyanate, or 2,6-tolylene diisocyanate, and the aromatic isocyanate-derived structure is contained in an amount of 50% by mass or more in 100% by mass of the polyisocyanate-derived structure of the urethane resin (A).

[0031] <Embodiment Satisfying the Requirement for Viscosity at 30% by Mass of Solid Content of Urethane Resin (A)> As an embodiment satisfying the requirement for the viscosity at 30% by mass of the solid content of the above-described urethane resin (A), the mode of the above-described <Embodiment Satisfying the Requirement for Breaking Stress of Urethane Resin (A)> can be adopted.

[0032] As a more preferred embodiment for satisfying the requirement of the viscosity of the urethane resin (A) at 30% by mass of the solid content, in the urethane resin (A), the weight average molecular weight is 10,000 to 200,000, the total of the urethane bond concentration and the urea bond concentration is 2.2 to 4.0 mmol / g, the mass ratio of the polyester polyol and the polyether polyol constituting the urethane resin (A) is 50:50 to 99:1, the polyisocyanate constituting the urethane resin (A) is an aromatic isocyanate such as tolylene diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, etc., and the content of the aromatic isocyanate-derived structure is 50% by mass or more in 100% by mass of the polyisocyanate-derived structure of the urethane resin (A).

[0033] <Urethane resin (A)> The stress at break of the urethane resin (A) is preferably 10 to 30 MPa, more preferably 12 to 28 MPa, and still more preferably 14 to 26 MPa. When the stress at break is within the above range, the blocking resistance and the high-temperature laminate strength are improved.

[0034] The viscosity of the urethane resin (A) measured according to JIS K 7117-1 at a liquid temperature of 25°C and a solid content of 30% by mass is 800 mPa·s or more, preferably 1000 to 4000 mPa·s, more preferably 1100 to 3000 mPa·s, still more preferably 1200 to 2500 mPa·s, and particularly preferably 1200 to 2000 mPa·s. By using the urethane resin (A) showing the viscosity within the above range under the above conditions, the blocking resistance, the high-temperature laminate strength, and the stability over time are improved.

[0035] In the present invention, the viscosity of the urethane resin was measured under the following conditions in accordance with JIS K 7117-1 using a Viscometer TUB-10 manufactured by Toki Sangyo Co., Ltd. 《Measurement conditions》 · Rotor: M3 · Rotation speed: 12 rpm · Liquid temperature: 25 °C · Solids content: 30% by mass · Solvent composition: ethyl acetate / isopropanol = 7 / 3

[0036] The urethane resin (A) is preferably a urethane resin having an amino group at the terminal, which is obtained by reacting a urethane prepolymer having terminal isocyanate composed of a polyol and a polyisocyanate with an amine-based chain extender. In this case, a urethane bond is formed by the reaction of the polyol and the polyisocyanate, and a urea bond is formed by reacting the urethane prepolymer having terminal isocyanate with the amine-based chain extender. Such a urethane resin can be synthesized, for example, by the methods described in JP-A-2013-256551 and JP-A-2016-043600.

[0037] When obtaining the urethane resin (A), the reaction molar ratio (NCO molar equivalent / OH molar equivalent) of NCO derived from the polyisocyanate to OH containing the polyol and the aliphatic diol is preferably 0.5 to 3, and more preferably 1.05 to 2. When the reaction molar ratio (NCO molar equivalent / OH molar equivalent) of NCO derived from the polyisocyanate to OH containing the polyol and the aliphatic diol is within the above range, the blocking resistance and the high-temperature lamination strength are improved. Next, chain extension can be carried out with the above-mentioned polyamine as necessary, and a reaction terminator can also be used to prevent an excessive reaction.

[0038] <Polyol constituting the urethane resin (A)> The polyol constituting the urethane resin (A) preferably has an average of 1 to 5 hydroxyl groups in one molecule, and more preferably 1.7 to 2.3 hydroxyl groups. As the polyol constituting the urethane resin (A), various known polyester polyols, polyether polyols, polycarbonate polyols, polycaprolactone diols, polyolefin polyols, castor oil polyols, hydrogenated castor oil polyols, etc. can be used. It is preferably a polyester polyol and / or a polyether polyol, more preferably a polyester polyol, and even more preferably a polyester polyol and a polyether polyol. The above polyols may be used alone or in combination of two or more. Further, the polyol preferably has a branched structure. From the viewpoints of the stability over time and blocking resistance of the urethane resin (A), the number average molecular weight of the polyol constituting the urethane resin (A) is preferably 300 or more, more preferably 500 to 6,000, and even more preferably 1,000 to 3,000.

[0039] <The polyester polyol constituting the urethane resin (A)> Examples of the polyester polyol constituting the urethane resin (A) include polyester polyols obtained by dehydration condensation or polymerization of saturated or unsaturated low molecular polyols such as ethylene glycol, 1,2-propanediol, 1,3-propanediol, etc. and polyvalent carboxylic acids such as adipic acid, phthalic acid, isophthalic acid, terephthalic acid, maleic acid, fumaric acid, succinic acid, oxalic acid, malonic acid, glutaric acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, trimellitic acid, pyromellitic acid, etc. or anhydrides thereof, and polyester polyols obtained by ring-opening polymerization of cyclic ester compounds such as lactones such as polycaprolactone, polyvalerolactone, poly(β-methyl-γ-valerolactone), etc. Among them, polyester polyols obtained by dehydration condensation or polymerization of polyvalent carboxylic acids or anhydrides thereof are preferred, and the polyvalent carboxylic acid is more preferably at least one selected from the group consisting of succinic acid, adipic acid, and sebacic acid, and even more preferably succinic acid and / or sebacic acid.

[0040] In the urethane resin (A), the mass ratio of the polyester polyol to the polyether polyol is preferably 50:50 to 99:1, more preferably 55:45 to 95:5, and still more preferably 60:40 to 90:10. When the mass ratio of the polyester polyol to the polyether polyol is within the above range, the blocking resistance and the stability over time are improved.

[0041] <Polyol constituting the urethane resin (A)> The polyol constituting the urethane resin (A) preferably contains a diol. Examples of the aliphatic diol include linear diols such as ethylene glycol, propylene glycol, butylene glycol, diethylene glycol, triethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,6-hexanediol, 1,8-octanediol, 1,9-nonanediol, etc., branched diols such as 1,2-propanediol, neopentyl glycol, 3-methyl-1,5-pentanediol, 2,4-diethyl-1,5-pentanediol, butylethylpropanediol, methylnonanediol, etc., and alicyclic diols such as cyclohexanedimethanol and cyclohexanediol. These may be used alone or in combination of two or more. Among them, aliphatic diols having an alkyl group having 1 to 6 carbon atoms as a substituent are preferable from the viewpoints of blocking resistance and high-temperature laminate strength. More specifically, 3-methyl-1,5-pentanediol, 2,4-diethyl-1,5-pentanediol, butylethylpropanediol, 2-methyl-1,3-propanediol, and neopentyl glycol are preferably used.

[0042] <Polyisocyanate constituting the urethane resin (A)> As the polyisocyanate, it is preferable to use diisocyanate. For example, aromatic diisocyanates such as tolylene diisocyanate, aliphatic diisocyanates such as hexamethylene diisocyanate, alicyclic diisocyanates such as isophorone diisocyanate, and dimer diisocyanate obtained by converting the carboxyl group of dimer acid into an isocyanate group can be mentioned. These may be used alone or in combination of two or more. Among them, from the viewpoints of blocking resistance and high-temperature lamination strength, aromatic isocyanate and / or alicyclic isocyanate is preferable, and aromatic isocyanate is more preferable. As the aromatic isocyanate, it is preferably tolylene diisocyanate, 2,4-tolylene diisocyanate or 2,6-tolylene diisocyanate, and more preferably tolylene diisocyanate. When the above isocyanate is used, the blocking resistance and high-temperature lamination strength are improved.

[0043] In 100% by mass of the polyisocyanate-derived structure of the urethane resin (A), the content of the aromatic isocyanate-derived structure is preferably 50% by mass, more preferably 70% by mass or more, and still more preferably 90% by mass or more. When the content of the aromatic isocyanate-derived structure is within the above range, the blocking resistance and lamination strength are improved.

[0044] <The polyamine constituting the urethane resin (A)> As the polyamine used for chain extension, aliphatic diamines such as ethylenediamine, 1,4-butanediamine, isophoronediamine, and aminoethylethanolamine are preferably used. Examples of the reaction terminator include alkylamines such as n-propylamine, n-butylamine, and di-n-butylamine, and alkanolamines such as monoethanolamine and diethanolamine.

[0045] <The acid group of the urethane resin (A)> The urethane resin (A) may have an acid group at any site of the urethane resin, such as the terminal or side chain. As the acid group, known functional groups such as a carboxyl group, a sulfonic acid group, and a phosphoric acid group can be used, but a carboxyl group is preferable, and a free carboxyl group is more preferable. The introduction position of the acid group is preferably the side chain of the urethane resin (A). Examples of the compound used for introducing a carboxyl group include compounds having a free carboxyl group and one or more active hydrogens that react with an isocyanate group, and cyclic dicarboxylic anhydrides. Examples of the compound having a free carboxyl group and one or more active hydrogens that react with an isocyanate group include various known compounds such as 2,2-dimethylolpropionic acid, 2,2-dimethylolbutanoic acid, 2,2-dimethylolpentanoic acid, 2,2-dimethylolbutyric acid, 2,2-dimethylolvaleric acid, dihydroxybenzoic acid, glycolic acid, 12-hydroxystearic acid, ricinoleic acid, and salicylic acid, and hydroxycarboxylic acids such as glutamic acid, alanine, tyrosine, serine, 6-aminocaproic acid, monoaminobenzoic acid, diaminobenzoic acid, and aminophthalic acid, and various known aminocarboxylic acids can be used. As the cyclic dicarboxylic anhydride, various known compounds such as maleic anhydride, phthalic anhydride, trimellitic anhydride, pyromellitic anhydride, and succinic anhydride can be used, and one or more of them can be used respectively.

[0046] The elongation at break of the urethane resin (A) is preferably 500 to 2000%, and more preferably 600 to 1700%. When the elongation at break is within the above range, the followability to the film is excellent, so the high-temperature lamination strength is improved.

[0047] <Embodiment Satisfying the Requirement of Elongation at Break of Urethane Resin (A)> As an embodiment satisfying the requirement of the elongation rate of the urethane resin (A), the mode of the above <Embodiment Satisfying the Requirement of Breaking Stress of Urethane Resin (A)> can be adopted. As a more preferred embodiment, in the urethane resin (A), the weight average molecular weight is 10,000 to 200,000, the glass transition temperature is -30 to 20 °C, the amine value is 0.3 to 15 mgKOH / g, the hydroxyl value is 0 to 3 mgKOH / g, the total of the urethane bond concentration and the urea bond concentration is 2.2 to 4.0 mmol / g, and as the polyisocyanate, aromatic isocyanates such as 2,4-tolylene diisocyanate and 2,6-tolylene diisocyanate are used. In 100% by mass of the polyisocyanate-derived structure of the urethane resin (A), the content of the aromatic isocyanate-derived structure is 50% by mass or more.

[0048] <urethane resin (a1)> The urethane resin (A) preferably contains a urethane resin (a1) having an acid value of less than 1 mgKOH / g. The acid value of the urethane resin (a1) is less than 1 mgKOH / g, more preferably 0.5 mgKOH / g or less, and still more preferably 0.3 mgKOH / g or less.

[0049] The amine value of the urethane resin (a1) is preferably 0.3 to 15 mgKOH / g, more preferably 0.5 to 13 mgKOH / g, and still more preferably 2 to 10 mgKOH / g. When the amine value of the urethane resin (a1) is within the above range, the high-temperature lamination strength with respect to the substrate is improved.

[0050] The hydroxyl value of the urethane resin (a1) is preferably 0 to 3 mgKOH / g, more preferably 1 to 3 mgKOH / g, and still more preferably 1.5 to 2.5 mgKOH / g. When the hydroxyl value of the urethane resin (a1) is within the above range, the stability over time, the blocking resistance, and the high-temperature lamination strength are improved.

[0051] The weight average molecular weight of the urethane resin (a1) is preferably from 10,000 to 200,000, more preferably from 30,000 to 100,000. When the weight average molecular weight of the urethane resin (A) is within the above range, the stability over time, blocking resistance, and high-temperature lamination strength are improved.

[0052] The glass transition temperature of the urethane resin (a1) is preferably from -30 to 20°C, more preferably from -20 to 10°C. When the glass transition temperature of the urethane resin (a1) is within the above range, the blocking resistance and residual solvent are improved.

[0053] The urethane bond concentration of the urethane resin (a1) is preferably from 0.6 to 3.6 mmol / g, more preferably from 1.0 to 2.6 mmol / g. When the urethane bond concentration of the urethane resin (a1) is within the above range, the blocking resistance and high-temperature lamination strength are improved. The urea bond concentration of the urethane resin (a1) is preferably from 0.4 to 1.8 mmol / g, more preferably from 0.5 to 1.4 mmol / g. When the urea bond concentration of the urethane resin (a1) is within the above range, the blocking resistance and high-temperature lamination strength are improved. The total of the urethane bond concentration and the urea bond concentration of the urethane resin (a1) is preferably from 2.2 to 4.0 mmol / g, more preferably from 2.5 to 3.0 mmol / g. When the total of the urethane bond concentration and the urea bond concentration of the urethane resin (a1) is within the above range, the blocking resistance and high-temperature lamination strength are improved.

[0054] <Urea bond concentration> The urea bond concentration is a value expressed as follows. After synthesizing a prepolymer having a terminal isocyanate group under the condition that (NCO mole number / OH mole number) > 1 and then chain-extending with a polyamine, when the urethane resin has an amino group at the terminal, the urea bond concentration is represented by the following (Formula 1). (Formula 1) Urea bond concentration (mmol / g) = [Total number of moles of isocyanate groups (mmol) - Total number of moles of hydroxyl groups (mmol)] / Total mass of solids (g)

[0055] After synthesizing a prepolymer having terminal isocyanate groups under conditions such that (moles of NCO groups / moles of OH groups) > 1, and then chain-extending with a polyamine, when the urethane resin has isocyanate groups at its terminals, the urea bond concentration is represented by the following (Formula 2). (Formula 2) Urea bond concentration (mmol / g) = (Total number of moles of amino groups (mmol)) / Total mass of solids (g) Here, the total number of moles of amino groups refers to the total number of moles of primary or secondary amino groups that the polyamine used to react with the prepolymer having terminal isocyanate groups to form urea bonds has.

[0056] <Urethane bond concentration> The urethane bond concentration is a value represented as follows. When (moles of NCO groups / moles of OH groups) > 1 in the raw materials constituting the urethane resin, the urethane bond concentration is represented by the following (Formula 3). (Formula 3) Urethane bond concentration (mmol / g) = Total number of moles of hydroxyl groups (mmol) / Total mass of solids (g) Here, the total number of moles of hydroxyl groups refers to the total number of moles of hydroxyl groups that polyols, etc. used in the reaction to form urethane have. Also, the total solids refer to the total mass of the non-volatile components that become the urethane resin. When (moles of NCO groups / moles of OH groups) < 1 in the raw materials constituting the urethane resin, the urethane bond concentration is represented by the following (Formula 4). (Formula 4) Urethane bond concentration (mmol / g) = Total number of moles of isocyanate groups (mmol) / Total mass of solids (g) Here, the total number of moles of isocyanate groups refers to the total number of moles of isocyanate groups that the polyisocyanate used in the reaction to form urethane has.

[0057] <Urethane resin (a2)> It is also preferable that the urethane resin (A) further contains a urethane resin (a2) having an acid value of 1 mgKOH / g or more. The elongation at break of the urethane resin (a2) is preferably 300 to 1500%, more preferably 500 to 1200%. When the elongation at break is within the above range, the followability to the film is excellent, so the high-temperature lamination strength is improved.

[0058] The acid value of the urethane resin (a2) is 1 mgKOH / g or more, preferably 1.1 to 8 mgKOH / g, more preferably 1.2 to 5 mgKOH / g, and still more preferably 1.3 to 3 mgKOH / g. When the acid value of the urethane resin (a2) is within the above range, the stability over time and the high-temperature lamination strength are improved.

[0059] The amine value of the urethane resin (a2) is preferably 0.1 to 10 mgKOH / g, more preferably 0.2 to 5 mgKOH / g, and still more preferably 0.3 to 2 mgKOH / g. When the amine value of the urethane resin (a2) is within the above range, the stability over time is improved.

[0060] The hydroxyl value of the urethane resin (a2) is preferably 1.0 to 3.0, more preferably 1.0 to 2.5. When the hydroxyl value of the urethane resin (a2) is within the above range, the stability over time, the blocking resistance, and the high-temperature lamination strength are improved.

[0061] The weight average molecular weight of the urethane resin (a2) is preferably 10,000 to 200,000, more preferably 30,000 to 100,000. When the weight average molecular weight of the urethane resin (a2) is within the above range, the stability over time, the blocking resistance, and the high-temperature lamination strength are improved.

[0062] The glass transition temperature of the urethane resin (a2) is preferably -30 to 20°C, more preferably -20 to 10°C. When it is within the above range, the blocking resistance and the residual solvent are improved. When the glass transition temperature of the urethane resin (a2) is within the above range, the stability over time and the high-temperature lamination strength are improved.

[0063] The urethane bond concentration of the urethane resin (a2) is preferably 0.6 to 3.6 mmol / g, more preferably 1.0 to 2.6 mmol / g. When the urethane bond concentration of the urethane resin (a2) is within the above range, the blocking resistance and the high-temperature lamination strength are improved. The urea bond concentration of the urethane resin (a2) is preferably 0.4 to 1.8 mmol / g, more preferably 0.5 to 1.4 mmol / g. When the urea bond concentration of the urethane resin (a2) is within the above range, the blocking resistance and the high-temperature lamination strength are improved. The total of the urethane bond concentration and the urea bond concentration of the urethane resin (a2) is preferably 2.2 to 4.0 mmol / g, more preferably 2.5 to 3.0 mmol / g. When the total of the urethane bond concentration and the urea bond concentration of the urethane resin (a2) is within the above range, the blocking resistance and the high-temperature lamination strength are improved.

[0064] The mass ratio of the urethane resin (a1) to the urethane resin (a2) is preferably 9.9:0.1 to 2:8, still more preferably 7:3 to 4:6. When the mass ratio of the urethane resin (a1) to the urethane resin (a2) is within the above range, the stability over time and the high-temperature lamination strength are improved.

[0065] <Resin other than urethane resin (A)> The gravure or flexographic ink of the present invention may contain resins other than the urethane resin (A) as long as the effects of the present invention are not impaired. Examples of such resins include polyamide resins, rosin-modified resins, chlorinated rubber, cyclized rubber, vinyl chloride-based resins such as vinyl chloride-vinyl acetate copolymer resins, cellulose-based resins such as nitrocellulose, polyvinyl acetal-based resins such as polyvinyl butyral, polyester resins, ketone resins, ethylene-vinyl acetate resins, ethylene-vinyl alcohol resins, styrene-maleic acid resins, casein, and alkyd resins. These resins may be used alone or in combination of two or more. Among them, it is preferable to contain at least one resin selected from the group consisting of vinyl chloride-based resins, cellulose-based resins, and polyvinyl acetal-based resins. The mass ratio of the urethane resin (A) to the other resins is preferably 99:1 to 50:50, more preferably 97:3 to 70, and even more preferably 95:5 to 85:15. When the mass ratio is within the above range, the blocking resistance, high-temperature laminating strength, and stability over time are improved.

[0066] <Additives> The gravure or flexographic ink of the present invention can appropriately contain conventionally known additives. For example, in the production of gravure ink, as additives as needed, pigment derivatives, dispersants, wetting agents, adhesion aids, leveling agents, defoaming agents, antistatic agents, viscosity modifiers, metal chelates, trapping agents, anti-blocking agents, wax components other than the above, isocyanate-based curing agents, silane coupling agents, etc. can be used.

[0067] <Colorants> The gravure or flexographic ink of the present invention may contain a colorant, and the colorant is preferably a pigment. The available pigments are not particularly limited, and various inorganic pigments and organic pigments that can be used in general printing inks and paints can be preferably used. The content of these pigments is preferably 0.5 to 50% by mass in the total amount of the ink.

[0068] <Organic solvents> The gravure or flexo ink of the present invention preferably contains an organic solvent. Examples of the organic solvent include alcohol-based organic solvents such as methanol, ethanol, n-propanol, isopropanol, and butanol; ketone-based organic solvents such as acetone, methyl ethyl ketone, and methyl isobutyl ketone; ester-based organic solvents such as methyl acetate, ethyl acetate, propyl acetate, and butyl acetate; aliphatic hydrocarbon-based organic solvents such as n-hexane, n-heptane, and n-octane; and alicyclic hydrocarbon-based organic solvents such as cyclohexane, methylcyclohexane, ethylcyclohexane, cycloheptane, and cyclooctane. Considering the solubility and drying properties of the binder resin, it is preferable to use them in combination. Among them, the organic solvent is preferably an ester-based solvent and / or an alcohol-based solvent, and more preferably an ester-based organic solvent and an alcohol-based organic solvent for odor during printing and environmental compatibility.

[0069] The content of the organic solvent is preferably 30% by mass or more in the total amount of the printing ink. The content of the ester-based organic solvent in 100% by mass of the organic solvent contained in the ink is preferably 50 to 95% by mass, and more preferably 70 to 90% by mass. When the content of the ester-based organic solvent is within the above range, the stability over time and the high-temperature lamination strength are improved. The content of the alcohol-based organic solvent in 100% by mass of the organic solvent contained in the ink is preferably 5 to 50% by mass, and more preferably 10 to 30% by mass. When the content of the alcohol-based organic solvent is within the above range, the stability over time and the high-temperature lamination strength are improved. The mass ratio of the ester-based organic solvent to the alcohol-based organic solvent in the ink is preferably 50:50 to 95:5, and more preferably 70:30 to 90:10. When the above mass ratio is within the above range, the stability over time and the high-temperature lamination strength are improved.

[0070] <Manufacture of Ink> The ink of the present invention can be produced by first stirring and mixing a urethane resin (A), an organic solvent, and, if necessary, a pigment, a resin other than the urethane resin (A), a pigment dispersant, a surfactant, etc., and then dispersing using various pigment dispersing machines such as a bead mill, a ball mill, a sand mill, an attritor, a roll mill, a pearl mill, etc., and further mixing various additives and organic solvents. Further, the present invention can also be applied to a medium ink or the like that does not contain a pigment.

[0071] <Printing method> The printing method of the ink of the present invention is gravure printing or flexographic printing, but gravure printing is preferred.

[0072] <Gravure printing> (Gravure plate) In the present invention, the gravure plate is a cylindrical one made of metal, and recesses are created in various colors by engraving or etching·laser. There are no restrictions on the use of engraving and laser, and they can be arbitrarily set according to the pattern. As the line number, those with 100 lines to 300 lines are appropriately used, and the larger the line number, the finer the printing can be. As the thickness of the printing layer, 0.1 μm to 100 μm is preferred. (Printing press) In a gravure printing press, one printing unit is equipped with the above-mentioned gravure plate and a doctor blade. There are a number of printing units, and printing units corresponding to organic solvent-based printing inks and pattern inks can be set, and each unit has an oven drying unit. Printing is performed by rotation and is a roll-fed printing method. The type of plate and the type of doctor blade are appropriately selected, and those corresponding to the specifications can be selected.

[0073] <Printed matter and laminate> The ink of the present invention can be printed on the substrate 1 by gravure printing or flexographic printing to obtain a printed matter. When the printed matter is used for back printing, it can also be laminated with at least one layer through an adhesive to form a laminate. Representative examples of the lamination process include the extrusion lamination method, the dry lamination method, the non-solvent lamination method, etc. The lamination process is a method in which an adhesive layer is provided on any surface of the printed matter by coating, drying, etc., and then thermocompression bonded to the substrate 2 for lamination.

[0074] <Substrate 1> Examples of the substrate 1 include polyethylene, polypropylene and other polyolefin substrates, polycarbonate substrates, polyethylene terephthalate, polylactic acid and other polyester substrates, polystyrene substrates, polystyrene-based resins such as AS resin or ABS resin, polyamide substrates, polyvinyl chloride substrates, various substrates of polyvinylidene chloride, cellophane substrates, paper substrates or aluminum foil substrates, etc., or film-like or sheet-like materials made of these composite materials. Among them, polyester substrates and polyamide substrates with a high glass transition temperature are preferably used.

[0075] <Substrate 2> Examples of the substrate 2 include the same ones as the substrate 1, and it may be the same as or different from the substrate 1. Note that the substrate 2 is preferably a thermoplastic substrate (sometimes referred to as a sealant), and an unstretched polyethylene substrate, an unstretched polypropylene substrate, an unstretched polyester substrate, etc. are preferred.

[0076] <Adhesive layer> The adhesive layer is not limited to the following, and examples thereof preferably include an anchor agent layer, a molten resin layer, a urethane-based adhesive layer, an acrylic-based adhesive layer, etc., and can be obtained by a melt extrusion method, a coating method, or the like. For example, as the urethane-based adhesive, a two-component adhesive composed of a mixture of a polyol and an isocyanate curing agent is suitable, and examples of the polyol include polyester-based and polyether-based polyols. Specifically, examples include TM-250HV / CAT-RT86L-60, TM-550 / CAT-RT37, TM-314 / CAT-14B, etc. manufactured by Toyo Morton Co., Ltd.

Example

[0077] Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited by these examples. Unless otherwise specified, "parts" described in this specification represent parts by mass, and "%" represents mass%.

[0078] The details of various measurements performed in the following examples are as follows.

[0079] <Viscosity> The viscosity of the urethane resin was measured in accordance with JIS K 7117-1 using a Viscometer TUB-10 manufactured by Toki Sangyo Co., Ltd. under the following conditions. <Measurement Conditions> · Rotor: M3 · Rotation speed: 12 rpm · Liquid temperature: 25°C · Solids content 30% by mass · Solvent composition: Ethyl acetate / Isopropanol = 7 / 3

[0080] <Stress and elongation at break> Each polyurethane resin solution obtained in the synthesis examples described below was dried to prepare a coating film test sample (thickness 0.30 mm, width 5.0 mm, length 20.0 mm). For each sample, a small tensile tester manufactured by Instron was used, and each was carried out under the conditions of a tensile speed of 50 mm / min and a room temperature of 25°C, and the stress and elongation at break of the sample at the time of break were measured.

[0081] <Weight-average molecular weight> The weight-average molecular weight was determined by the GPC (gel permeation chromatography) method. The molecular weight distribution was measured using "Shodex GPC System-21" manufactured by Showa Denko K.K., and the molecular weight in terms of polystyrene was determined. The measurement conditions are shown below. Column: A plurality of the following columns were connected in series and used. TSKgel Super AW2500, manufactured by Tosoh Corporation, TSKgel Super AW3000, manufactured by Tosoh Corporation, TSKgel Super AW4000, manufactured by Tosoh Corporation, TSKgel guard column Super AW-H, manufactured by Tosoh Corporation Detector: RI (differential refractometer), Measurement conditions: Column temperature 40°C, Eluent: Dimethylformamide Reference substance: Polystyrene Flow rate: 0.5 mL / min

[0082] <Hydroxyl value> It was determined according to the method described in JIS K0070.

[0083] <Acid value> It was determined according to the method described in JIS K0070.

[0084] <Amine value> The amine value was determined according to the following method in accordance with JIS K0070 as the number of mg of potassium hydroxide equal to the equivalent amount of hydrochloric acid required to neutralize the amino groups contained in 1 g of the resin. The sample was accurately weighed at 0.5 to 2 g (sample solid content: S g). 50 mL of a mixed solution of methanol / methyl ethyl ketone = 60 / 40 (mass ratio) was added to the accurately weighed sample and dissolved. Bromophenol blue was added as an indicator to the resulting solution, and the resulting solution was titrated with a 0.2 mol / L ethanolic hydrochloric acid solution (titer: f). The point at which the color of the solution changed from green to yellow was taken as the end point, and using the titration volume (A mL) at this time, the amine value was determined by the following (Equation 5). (Equation 5) Amine value = (A × f × 0.2 × 56.108) / S [mg KOH / g]

[0085] <Synthesis Example 1> Into a four-necked flask equipped with a stirrer, thermometer, reflux condenser, and nitrogen gas inlet tube, 12.57 parts of polyester polyol PEs1 (a polyester polyol that is a condensate of adipic acid and 2-methyl-1,3-propanediol, number average molecular weight 1000), 6.77 parts of polyether polyol (poly(1,2-propylene glycol), number average molecular weight 1000) (hereinafter PPG), 0.22 parts of N-methyldiethanolamine (hereinafter MDA), 0.92 parts of neopentyl glycol (hereinafter NPG), 7.32 parts of tolylene diisocyanate (hereinafter TDI), 20 parts of ethyl acetate, and 0.002 parts of tin catalyst (tin 2-ethylhexanoate) were charged. The reaction was carried out at 90 °C for 6 hours under a nitrogen stream, 10 parts of ethyl acetate was added, and the mixture was cooled to obtain a solution of a terminal isocyanate prepolymer. Next, 1.96 parts of isophoronediamine (hereinafter IPDA), 0.13 parts of n-dibutylamine (hereinafter DBA), 0.11 parts of aminoethylethanolamine (hereinafter AEA), 19 parts of ethyl acetate, and 21 parts of isopropyl alcohol (hereinafter IPA) were mixed, and the obtained solution of the terminal isocyanate prepolymer was gradually added thereto at room temperature. Next, the reaction was carried out at 50 °C for 1 hour to obtain a urethane resin (a1) solution (PU-1) having a solid content of 30%, a mass average molecular weight of 55000, an amine value of 7.5 mgKOH / g, a urethane bond concentration of 2 mmol / g, a urea bond concentration of 0.8 mmol / g, a viscosity of 1600 mPa·s, a breaking stress of 15 Pa, and an elongation rate of 700%.

[0086] <Synthesis Examples 2 to 14, Comparative Synthesis Examples 19 to 21> Urethane resin solutions (PU-2 to 14, PU-19 to 21) were obtained in the same manner as in Synthesis Example 1, except that the composition was changed to that described in Table 1. The details of the abbreviations in the table are as follows. ·PEs2: A polyester polyol that is a condensate of adipic acid and 2-methyl-1,3-propanediol, number average molecular weight 2000 ·PEs3: (3-Methyl-1,5-pentanedipate) glycol, number average molecular weight 2000 ·IPDI: Isophorone diisocyanate ·AAS: N-Aminoethyl-3-aminopropyltrimethoxysilane

[0087] <Synthesis Example 15> Into a four-necked flask equipped with a stirrer, thermometer, reflux condenser, and nitrogen gas inlet tube, 12.93 parts of polyester polyol PEs1, 0.04 part of MDA, 0.11 part of dimethylolbutanoic acid (DMBA), 7.32 parts of TDI, 20 parts of ethyl acetate, and 0.002 part of tin catalyst (tin 2-ethylhexanoate) were charged, and the reaction was carried out at 90 °C for 6 hours under a nitrogen stream to obtain a solution of a terminal isocyanate prepolymer. Next, a mixture of 1.57 parts of IPDA, 0.1 part of AEA, 29 parts of ethyl acetate, and 21 parts of IPA was gradually added to the obtained solution of the terminal isocyanate prepolymer at room temperature for chain extension, and then the reaction was carried out at 50 °C for 1 hour to obtain a urethane resin (a2) solution (PU-13) with a solid content of 30%, acid value of 1.4 mg KOH / g, amine value of 0.65 mg KOH / g, urethane bond concentration of 2 mmol / g, urea bond concentration of 0.8 mmol / g, weight average molecular weight of 40,000, viscosity of 1200 mPa·s, breaking stress of 10 mPa, and elongation rate of 800%.

[0088] <Synthesis Examples 16 to 18, Comparative Synthesis Examples 22 to 24> Urethane resin solutions (PU-16 to 18, 22 to 24) were obtained in the same manner as in Synthesis Example 15, except that the compounding compositions described in Table 1 were changed.

[0089]

Table 1

[0090]

Table 1

[0091] <Example 1> 35 parts of titanium oxide pigment (manufactured by Teika Co., Ltd., rutile-type titanium oxide surface-treated with silica and alumina, oil absorption 21 g / 100 g, solid content 100%), 14 parts of urethane resin (a2) solution (PU-13), 9 parts of propyl acetate, 5 parts of ethyl acetate, and 5 parts of isopropyl alcohol were stirred and mixed, and the pigment was dispersed with a sand mill. Then, 18 parts of urethane resin (a1) solution (PU-1), 3 parts of vinyl acetal resin solution (a polyvinyl butyral resin having vinyl alcohol units, vinyl acetate units, and vinyl butyral units, containing 73% by mass of butyral ring groups, glass transition point 70 °C, weight average molecular weight 50,000, chlorine content 0% by mass, nitration degree 0% by mass) in a 30% by solid content solution of ethyl acetate / isopropanol = 1 / 1 mixed solvent, 5 parts of propyl acetate, 3 parts of ethyl acetate, 1.8 parts of isopropyl alcohol, 0.5 part of chlorinated polypropylene (weight average molecular weight 30,000, chlorine content 30% by mass, nitration degree 0% by mass, solid content 30%, ethyl acetate solution), 0.5 part of amide wax (manufactured by Kao Chemical Co., Ltd., amide P, solid content 20%, ethyl acetate solution), and 0.2 part of antifoaming agent (manufactured by BYK Co., Ltd., BYK-051N, solid content 20%, mineral spirit solution) were stirred and mixed to obtain white printing ink X1.

[0092] <Examples 2 to 29, Comparative Examples 1 to 3> Printing inks were obtained in the same manner as in Example 1, except that the composition was changed to that described in Table 2 or Table 3. The details of the raw materials used are as follows. · Vinyl chloride resin solution: A 30% by solid content ethyl acetate solution of a vinyl chloride-vinyl acetate copolymer resin (Solvain TA3 manufactured by Nisshin Chemical Co., Ltd., chlorine content 47.1% by mass, nitration degree 0% by mass) · Cellulose resin solution: A 30% by solid content ethyl acetate solution of a cellulose acetate propionate resin (CAP-504-0.2 manufactured by Eastman Chemical Co., Ltd., glass transition point 160 °C, weight average molecular weight 40,000, chlorine content 0% by mass, nitration degree 0% by mass) · Rosin resin solution: A 30% solids ethyl acetate solution of pentaerythritol rosin ester (Hariester P manufactured by Harima Kasei Co., Ltd., softening point 100 °C, acid value 10 mgKOH / g, weight average molecular weight 1,500, chlorine content 0 mass%, nitration degree 0 mass%) · Polyamide resin solution: A 30% solids isopropyl alcohol solution of polyamide resin (manufactured by Tsukino Food Industry Co., Ltd., product name Vegichem Green 725, softening point 116 °C, weight average molecular weight 8,000)

[0093]

Table 2

[0094]

Table 2

[0095]

Table 3

[0096] <Preparation of a printed matter using the ink of Example 1> The viscosity of the ink of Example 1 was adjusted by dilution with an ethyl acetate / isopropyl alcohol mixed solvent (mass ratio 75 / 25) so that the viscosity in a Zahn cup #3 (manufactured by Rika Co., Ltd.) was 15 seconds (at 25 °C). Using a gravure printing press equipped with a gravure plate with a plate depth of 30 μm, it was printed on a one-sided corona-treated polypropylene (OPP) film (Pyren P2161 manufactured by Toyobo Co., Ltd.) and dried at 45 °C to obtain a printed matter using the ink of Example 1.

[0097] <Preparation of printed matters using the inks of Examples 2 to 29 and Comparative Examples 1 to 3> Except for using the inks described in Table 2 or 3, printed matters using the inks of Examples 2 to 29 and Comparative Examples 1 to 3 were obtained in the same manner as in Example 1 above.

[0098] (Evaluation) Using the printing inks obtained in the above Examples and Comparative Examples, and the printed materials thereof, evaluations of stability over time, blocking resistance, residual solvents, and high-temperature lamination strength were conducted by the methods described below.

[0099] <Stability over time> After allowing the obtained printing ink to stand in a constant-temperature chamber at 40°C for one week, the stability was evaluated according to the following criteria. The practical level is A to C. (Evaluation criteria) A: No thickening, precipitation, or separation is observed. B: Slight thickening or slight precipitation is observed. C: Slight separation is observed. D: Thickening, precipitation, or separation is observed.

[0100] <Blocking resistance> Two pieces of the obtained printed material were cut out into 4-cm squares. The printed surface of one piece of the printed material and the unprinted surface of the other piece of the printed material were completely overlapped, and a load of 100 kg / cm 2 was applied. After leaving it in an atmosphere at a temperature of 40°C and a humidity of 80% RH for 24 hours, the blocking resistance was evaluated from the degree of the peeling state when the printed surface was peeled off. The practical level is A to C. (Evaluation criteria) A: The printing ink film does not peel off at all, and the peeling resistance is small. B: The peeled area of the printing ink film is 1% or more and less than 15%, and the peeling resistance is small. C: The peeled area of the printing ink film is 15% or more and less than 50%. D: The printing ink film peels off by 50% or more.

[0101] <Residual solvents> The obtained printed material was cut out so as to be 0.2 m 2 and heated in a sealed Erlenmeyer flask at 80°C for 30 minutes to volatilize the solvent. It was analyzed by gas chromatography (manufactured by GL Sciences Inc., GC-4000) to confirm the amount of the volatilized solvent. The practical level is A to C. (Evaluation criteria) A: The total amount of the residual solvents is 0.5 mg / m2 Those less than B: The total amount of residual solvents is 0.5 mg / m 2 2 mg / m or more 2 Those less than C: The total amount of residual solvents is 2 mg / m 2 3 mg / m or more 2 Those less than D: The total amount of residual solvents is 3 mg / m 2 Those 3 mg / m or more

[0102] <High-temperature laminate strength> A methanol solution (solid content 1% by mass) of an imine-based anchor coating agent (EL420 manufactured by Toyo Morton Co., Ltd.) was applied to the obtained printed matter, and molten polyethylene (LC600A manufactured by Nippon Polyethylene Co., Ltd.) was extruded at 320 °C at a line speed of 100 m / min by an extrusion laminating machine (manufactured by Musashino Kikai Co., Ltd.) and laminated at 18 μm. At the same time, CPP (FCMN film thickness 20 μm manufactured by Futamura Chemical Co., Ltd.) was laminated in the same manner to obtain a laminate. Regarding the laminate, it was cut out into a length of 150 mm and a width of 15 mm so that the long side was in the MD direction, opened at the printed ink / OPP film interface, and the laminate strength in the 90° direction was measured using a tensile tester under the condition of a temperature of 60 °C. The practical level is A to C. When the ink of the present invention is used for a packaging material, during transportation in summer and the like, due to the influence of recent global warming, it is assumed to be stored at high temperature and come into contact with other packaging materials. When external stimuli such as contact occur at high temperature, the risk of delamination of the packaging material increases. Therefore, the laminate strength in the present invention was carried out under unprecedented high-temperature conditions. (Evaluation criteria) A: 1.2 N / 15 mm or more B: 1.0 N / 15 mm or more and less than 1.2 N / 15 mm C: 0.5 N / 15 mm or more and less than 1.0 N / 15 mm D: Less than 0.5 N / 15 mm

[0103] From the above results, in Comparative Example 1, since the viscosity measured by JIS K 7117-1 at a liquid temperature of 25°C and a solid content of 30% by mass of the urethane resin was less than 800 mPa·s, the stability over time and blocking resistance were poor. In Comparative Example 2, since the stress at break of the urethane resin was less than 10 MPa, the blocking resistance was poor. In Comparative Example 3, since the total of the urethane bond concentration and the urea bond concentration of the urethane resin exceeded 4 mmol / g, the residual solvent amount and the high-temperature lamination strength were poor. On the other hand, in the examples, the urethane resin (A) was included, and either the stress at break of the urethane resin (A) was 10 MPa or more, or the total of the urethane bond concentration and the urea bond concentration of the urethane resin (A) was 2.2 to 4 mmol / g, and the viscosity measured according to JIS K 7117-1 at a liquid temperature of 25°C and a solid content of 30% by mass of the urethane resin (A) was 800 mPa·s or more. Therefore, the stability over time, blocking resistance, high-temperature lamination strength, and low residual solvent were good.

Claims

1. A gravure or flexo ink containing a urethane resin (A), wherein the stress at break of the urethane resin (A) measured under the following conditions is 10 MPa or more, A gravure or flexo ink wherein the viscosity of the urethane resin (A) measured according to JIS K 7117-1 at a liquid temperature of 25 ° C and a solid content of 30% by mass is 800 mPa·s or more. (Stress measurement conditions) Tensile speed: 50 mm / min, temperature: 25 ° C Sample shape: thickness 0.3 mm, width 5 mm, length 20 mm

2. A gravure or flexo ink containing a urethane resin (A), wherein the total of the urethane bond concentration and the urea bond concentration of the urethane resin (A) is 2.2 to 4.0 mmol / g, A gravure or flexo ink wherein the viscosity of the urethane resin (A) measured according to JIS K 7117-1 at a liquid temperature of 25 ° C and a solid content of 30% by mass is 800 mPa·s or more.

3. The gravure or flexo ink according to claim 1 or 2, wherein the elongation at break of the urethane resin (A) measured under the following conditions is 500% or more. (Elongation measurement conditions) Tensile speed: 50 mm / min, temperature: 25 ° C Sample shape: thickness 0.3 mm, width 5 mm, length 20 mm

4. The gravure or flexo ink according to claim 1 or 2, wherein the urethane resin (A) contains an aromatic isocyanate-derived structure.

5. The gravure or flexo ink according to claim 1 or 2, wherein the urethane resin (A) contains a polyester-derived structure and / or a polyether-derived structure.

6. The gravure or flexographic ink according to claim 1, wherein the total of the urethane bond concentration and the urea bond concentration of the urethane resin (A) is 2.2 to 4.0 mmol / g.

7. The gravure or flexographic ink according to claim 1 or 2, wherein the urethane resin (A) contains a urethane resin (a1) having an acid value of less than 1 mg KOH / g.

8. The gravure or flexographic ink according to claim 7, wherein the urethane resin (A) further contains a urethane resin (a2) having an acid value of 1 mg KOH / g or more.

9. The gravure or flexographic ink according to claim 8, wherein the mass ratio of the urethane resin (a1) to the urethane resin (a2) is 9.9:0.1 to 2:

8.

10. The gravure or flexographic ink according to claim 1 or 2, further comprising at least one selected from the group consisting of a vinyl chloride resin, a vinyl acetal resin, and a cellulose resin.

11. A printed matter having a printing layer made of the gravure or flexographic ink according to claim 1 or 2 on a substrate 1.

12. A laminate having a printing layer made of the gravure or flexographic ink according to claim 1 or 2 on a substrate 1.

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