Composition for gravure ink, medium, gravure ink, and laminate

Abstract

To provide: a composition for gravure ink that improves the cuttability of a resulting laminate while satisfying the physical properties required of a composition for gravure ink; and a laminate having a printed layer formed from the composition for gravure ink.SOLUTION: A composition for gravure ink comprises a urethane resin, an organic solvent, and a difunctional polyisocyanate, and satisfies the following conditions (1) and (2): (1) the content of isocyanate groups relative to the total mass of the difunctional polyisocyanate is 15.0-35.0 mass%; and (2) the mass ratio, in terms of solid content, of the urethane resin to the difunctional polyisocyanate is between 13.0:1.0 and 3.0:1.0.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a gravure ink composition, a medium, a gravure ink, and a laminate. [Background technology]

[0002] Conventionally, various packaging materials have been used to store liquid, powder, or solid foods, detergents, miscellaneous goods, and the like. A known example of such packaging material is a packaging bag made from a laminate having a main plastic film (substrate) and a printed layer formed using printing ink. Packaging bags are required to be strong in order to protect the contents. Furthermore, packaging bags are required to have excellent ease of opening when in use (packaging material tearability, hereinafter also referred to as "tearability").

[0003] Patent Document 1 discloses that the cuttability of the resulting laminate is improved by using a printing ink composition for laminate containing a pigment, a binder resin having a specific structure, a trifunctional isocyanate compound (curing agent) having an isocyanurate ring, and an organic solvent. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2021-127429 Summary of the Invention [Problem to be solved by the invention]

[0005] However, even when the printing ink composition for laminate described in Patent Document 1 is used, the cuttability of the resulting laminate is insufficient. Furthermore, the inventors of the present application investigated the use of a trifunctional isocyanate compound other than the trifunctional isocyanate compound having an isocyanurate ring described in Patent Document 1 as a curing agent. As a result, it was found that, although the cuttability may be improved depending on the type of trifunctional isocyanate compound, the physical properties required for a gravure ink composition are not satisfied. Physical properties required for a gravure ink composition include the storage stability of the gravure ink composition (hereinafter also referred to as "ink stability") and printability. Furthermore, a printed layer obtained using a gravure ink or medium containing a gravure ink composition is also required to have high substrate adhesion and little residual organic solvent.

[0006] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a gravure ink composition which improves the cuttability of the resulting laminate and satisfies the physical properties required of a gravure ink composition, a medium and gravure ink containing the gravure ink composition, and a laminate having a printing layer formed from the medium and gravure ink. [Means for solving the problem]

[0007] In order to solve the above problems, the present invention has the following aspects. [1] A gravure ink composition comprising a urethane resin, an organic solvent, and a bifunctional polyisocyanate, and satisfying the following conditions (1) and (2): (1) The content of isocyanate groups relative to the total mass of the bifunctional polyisocyanate is 15.0 to 35.0% by mass. (2) The mass ratio of the urethane resin to the bifunctional polyisocyanate in terms of solid content is 13.0:1.0 to 3.0:1.0. [2] The gravure ink composition according to [1], wherein the urethane resin has a hydroxyl value of 10 to 45 mgKOH / g. [3] The gravure ink composition according to [1] or [2], wherein the urethane resin has a weight average molecular weight of 20,000 to 90,000. [4] The gravure ink composition according to any one of [1] to [3], which contains a vinyl chloride-vinyl acetate copolymer, and the mass ratio of the urethane resin to the vinyl chloride-vinyl acetate copolymer in terms of solid content is 1.0:0.10 to 1.0:1.0. [5] The gravure ink composition according to [4], wherein the vinyl chloride-vinyl acetate copolymer has a hydroxyl group and a hydroxyl value of 50 to 250 mgKOH / g. [6] A medium comprising the gravure ink composition according to any one of [1] to [5] and silica. [7] A gravure ink comprising the gravure ink composition according to any one of [1] to [5] and a pigment. [8] A laminate having a printed layer formed from the medium described in [6]. [9] A laminate having a printing layer formed from the gravure ink according to [7].

[0008] [1A] A gravure ink composition comprising a urethane resin, an organic solvent, and a bifunctional polyisocyanate, and satisfying the following conditions (1) to (7): (1) The content of isocyanate groups relative to the total mass of the bifunctional polyisocyanate is 15.0 to 35.0% by mass. (2) The mass ratio of the urethane resin to the bifunctional polyisocyanate in terms of solid content is 13.0:1.0 to 3.0:1.0. (3) The hydroxyl value of the urethane resin is 10 to 45 mgKOH / g. (4) The weight average molecular weight of the urethane resin is 20,000 to 90,000. (5) The content of the solid content of the urethane resin relative to the total mass of the solid content of the gravure ink composition is 10 to 65 mass %. (6) When the gravure ink composition further contains other resins in addition to the urethane resin, the content of the solid content of the other resins relative to the total mass of the solid content of the gravure ink composition is 3 to 30 mass %. (7) When the gravure ink composition further contains a tri- or higher functional polyisocyanate, the content of the tri- or higher functional polyisocyanate as a solid component relative to the total mass of the solid components of the gravure ink composition is 0.5 to 10 mass %. [2A] The gravure ink composition according to [1A], wherein the other resin is at least one selected from the group consisting of vinyl chloride-vinyl acetate copolymer, cellulose-based resin, polyester resin, and acrylic resin. [3A] The gravure ink composition according to [1A] or [2A], wherein the other resin comprises a vinyl chloride-vinyl acetate copolymer, and the mass ratio of the urethane resin to the vinyl chloride-vinyl acetate copolymer in terms of solid content is 1.0:0.10 to 1.0:1.0. [4A] The gravure ink composition according to [3A], wherein the vinyl chloride-vinyl acetate copolymer has a hydroxyl group and a hydroxyl value of 50 to 250 mgKOH / g. [5A] A medium comprising the gravure ink composition according to any one of [1A] to [4A] and silica. [6A] A gravure ink comprising the gravure ink composition according to any one of [1A] to [4A] and a pigment. [7A] A laminate having a printed layer formed from the medium according to [5A]. [8A] A laminate having a printing layer formed from the gravure ink according to [6A]. [Effects of the Invention]

[0009] According to the present invention, it is possible to provide a gravure ink composition that improves the cuttability of the resulting laminate and satisfies the physical properties required of a gravure ink composition, a medium and gravure ink that contain the gravure ink composition, and a laminate having a printing layer formed from the medium and gravure ink. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a cross-sectional view showing a laminate according to one embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0011] The following describes in detail the embodiments of the present invention. However, the following description is an example of an embodiment of the present invention, and the present invention is not limited to these contents and can be modified and implemented within the scope of its gist.

[0012] <Gravure ink composition> The gravure ink composition of this embodiment contains a urethane resin, an organic solvent, and a bifunctional polyisocyanate, and satisfies the following conditions (1) to (7). (1) The content of isocyanate groups relative to the total mass of the bifunctional polyisocyanate is 15.0 to 35.0% by mass. (2) The mass ratio of the urethane resin to the bifunctional polyisocyanate in terms of solid content is 13.0:1.0 to 3.0:1.0. (3) The hydroxyl value of the urethane resin is 10 to 45 mgKOH / g. (4) The weight average molecular weight of the urethane resin is 20,000 to 90,000. (5) The content of the solid content of the urethane resin relative to the total mass of the solid content of the gravure ink composition is 10 to 65 mass %. (6) When the gravure ink composition further contains other resins in addition to the urethane resin, the content of the solid content of the other resins relative to the total mass of the solid content of the gravure ink composition is 3 to 30 mass %. (7) When the gravure ink composition further contains a tri- or higher functional polyisocyanate, the content of the tri- or higher functional polyisocyanate as a solid component relative to the total mass of the solid components of the gravure ink composition is 0.5 to 10 mass %.

[0013] <Urethane resin> A urethane resin is a compound having a urethane bond and a group capable of reacting with an isocyanate group. Examples of the group capable of reacting with an isocyanate group include a hydroxyl group and an amino group. Examples of urethane resins include a reaction product of a polyisocyanate compound and a polyol compound. Furthermore, when the terminal of the reaction product of a polyisocyanate compound and a polyol compound is an isocyanate group, a chain extension reaction product obtained by further carrying out a chain extension reaction using a chain extender can also be used. A reaction terminator may be used to obtain the reaction product and the chain extension reaction product. That is, the urethane resin contains polyvalent isocyanate compound units and polyol compound units. The urethane resin may contain chain extender units and / or reaction terminator units.

[0014] Examples of the polyisocyanate compound include aliphatic, alicyclic, and aromatic polyisocyanate compounds. Specific examples of the polyisocyanate compound include aliphatic diisocyanates such as trimethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, pentamethylene diisocyanate, 1,2-propylene diisocyanate, 1,2-butylene diisocyanate, 2,3-butylene diisocyanate, 1,3-butylene diisocyanate, 2,4,4- or 2,2,4-trimethylhexamethylene diisocyanate, and 2,6-diisocyanate methyl caproate. Hydrogenated diphenylmethane diisocyanate, isophorone diisocyanate, norbornene diisocyanate, 1,3-cyclopentane diisocyanate, 1,4-cyclohexane diisocyanate, 1,3-cyclohexane diisocyanate, 3-isocyanatemethyl-3,5,5-trimethylcyclohexyl isocyanate (isophorone diisocyanate), 4,4'-methylenebis(cyclohexyl isocyanate), methyl-2,4-cyclohexane diisocyanate, methyl-2 Alicyclic diisocyanates such as 1,6-cyclohexane diisocyanate, 1,4-bis(isocyanatomethyl)cyclohexane, and 1,3-bis(isocyanatomethyl)cyclohexane; m-phenylene diisocyanate, p-phenylene diisocyanate, 4,4'-diphenyl diisocyanate, 1,5-naphthalene diisocyanate, 4,4'-diphenylmethane diisocyanate, 2,4- or 2,6-tolylene diisocyanate, 4,4'-toluidine diisocyanate, and dianisidine diisocyanate. Examples of suitable isocyanate compounds include aromatic diisocyanates such as benzene diisocyanate and 4,4'-diphenylether diisocyanate; polyisocyanate compounds that are adducts, isocyanurates, or biurets of the above diisocyanates; triisocyanates such as 1,3,5-triisocyanate benzene, 2,4,6-triisocyanate toluene, and 1,3,5-triisocyanate hexane; and polyisocyanates such as 4,4'-diphenyldimethylmethane-2,2'-5,5'-tetraisocyanate. These polyisocyanate compounds may be used alone or in combination of two or more.

[0015] Examples of polyol compounds include polyether polyols obtained by polymerizing oxirane compounds such as ethylene oxide, propylene oxide, butylene oxide, and tetrahydrofuran using a low-molecular-weight polyol such as ethylene glycol, propylene glycol, trimethylolpropane, and glycerin as an initiator; saturated or unsaturated glycols such as ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, 1,2-propanediol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, neopentyl glycol, pentanediol, 3-methyl-1,5-pentanediol, octanediol, 1,9-nonanediol, 1,8-nonanediol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, bisphenol A, and hydrogenated bisphenol A. polyester polyols obtained by dehydration condensation of glycols with dibasic acids such as adipic acid, maleic acid, fumaric acid, phthalic anhydride, isophthalic acid, terephthalic acid, succinic acid, oxalic acid, malonic acid, glutaric acid, pimelic acid, azelaic acid, sebacic acid, and suberic acid, or the corresponding acid anhydrides or dimer acids; polylactone polyols obtained by ring-opening polymerization of lactone monomers (γ-butyrolactone, γ-valerolactone, ε-caprolactone, and mixtures of two or more thereof) using the above-mentioned glycols as an initiator; polyolefin polyols such as polyethylene polyols and polypropylene polyols; polyether ester polyols obtained by reacting the above-mentioned dibasic acids or dialkyl esters thereof with the above-mentioned polyether polyols; and polycarbonate polyols obtained by reacting the above-mentioned glycols with methyl carbonate, diphenyl carbonate, ethylene carbonate, phosgene, or the like. These polyol compounds may be used alone or in combination of two or more.

[0016] Examples of the chain extender include polyamines and polyols having a number average molecular weight (Mn) or formula weight of less than 500. The chain extenders may be used alone or in combination of two or more.

[0017] Examples of polyamines include diamines having 2 to 12 carbon atoms, such as ethylenediamine, propylenediamine, hexamethylenediamine, isophoronediamine, toluenediamine, piperazine, and aminoethylethanolamine; polyalkylenepolyamines having 2 to 6 carbon atoms and 3 to 7 amino groups, such as diethylenetriamine, dipropylenetriamine, dihexylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, and hexaethyleneheptamine; and hydrazine or a derivative thereof (dibasic acid dihydrazide, for example, adipic acid dihydrazide). Among these, from the viewpoints of the cutting properties and substrate adhesion of the resulting printed layer and the ink stability of the gravure ink composition, alicyclic diamines are preferred, and isophoronediamine and aminoethylethanolamine are more preferred. One type of polyamine may be used alone, or two or more types may be used in combination.

[0018] Examples of polyols include alkylene oxide (hereinafter abbreviated as "AO") adducts of aliphatic dihydric alcohols having 2 to 8 carbon atoms; alicyclic group-containing dihydric alcohols having 6 to 10 carbon atoms such as 1,4-bis(hydroxymethyl)cyclohexane and 2,2-bis(4-hydroxycyclohexyl)propane; aromatic ring-containing dihydric alcohols having 8 to 20 carbon atoms such as m- or p-xylylene glycol, bis(hydroxyethyl)benzene, and bis(hydroxyethoxy)benzene; and bisphenols such as bisphenol A, bisphenol S, and bisphenol F; AO adducts of dihydroxynaphthalene, and bis(2-hydroxyethyl)terephthalate. Examples of the aliphatic dihydric alcohol having 2 to 8 carbon atoms include linear diols having hydroxyl groups only at the terminals of the linear chain structure, such as ethylene glycol, diethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, and 1,6-hexanediol; linear diols having hydroxyl groups other than at the terminals of the linear chain structure, such as 1,2-propanediol, 1,3-propanediol, and 2,3-propanediol; and diols having branched alkyl chains, such as neopentyl glycol, 3-methyl-1,5-pentanediol, and 2,2-diethyl-1,3-propanediol. Among these, from the viewpoint of the cutting properties of the resulting printed layer and the ink stability of the gravure ink composition, aliphatic dihydric alcohols having 2 to 8 carbon atoms are preferred, and 1,3-propanediol and 1,4-butanediol are more preferred. One type of polyol may be used alone, or two or more types may be used in combination.

[0019] Examples of the reaction terminator include monoalcohols having 1 to 10 carbon atoms, such as methanol, propanol, butanol, and 2-ethylhexanol, and monoamines having 2 to 8 carbon atoms. Examples of monoamines having 2 to 8 carbon atoms include mono- or di-alkylamines having 2 to 8 carbon atoms, such as n-butylamine and di-n-butylamine, and mono- or dialkanolamines having 2 to 6 carbon atoms, such as monoethanolamine, diethanolamine, and propanolamine. Among these, mono- or dialkanolamines having 2 to 6 carbon atoms are preferred. One type of reaction terminator may be used alone, or two or more types may be used in combination.

[0020] (Biomass urethane resin) In one aspect of the present invention, the urethane resin is preferably a biomass urethane resin. The biomass urethane resin refers to a urethane resin in which at least a portion of the units constituting the urethane resin are compound units derived from biomass. In particular, it is preferable that the polyol compound contains a compound unit derived from biomass and / or the chain extender is a compound derived from biomass.

[0021] When a biomass urethane resin is used, the biomass concentration in the resulting gravure ink composition can be increased, making the gravure ink composition an excellent material from the perspective of carbon neutrality. Previously, studies have been conducted to increase the biomass concentration in gravure ink compositions, but the performance has not been satisfactory. The inventors of the present application have discovered that using a bifunctional polyisocyanate as a curing agent improves overall performance compared to conventional petroleum-derived urethane resins. In particular, they have found that the cuttability and printability of the resulting printed layer are improved.

[0022] (Physical properties of urethane resin) The weight average molecular weight (Mw) of the urethane resin is 20,000 to 90,000, preferably 30,000 to 85,000, and more preferably 40,000 to 80,000 from the viewpoints of blocking resistance and compatibility. When the weight-average molecular weight is within the above range, both the cuttability and lamination strength of the resulting printed layer can be achieved. Furthermore, when the weight-average molecular weight (Mw) is less than 20,000, the blocking resistance is poor. When the weight-average molecular weight (Mw) is more than 90,000, the compatibility is poor. The Mw of the urethane resin is the weight average molecular weight converted into the molecular weight of standard polystyrene, and is measured by gel permeation chromatography (GPC).

[0023] The urethane resin may contain only hydroxyl groups, only amino groups, or both hydroxyl groups and amino groups as groups reactive with isocyanate groups.

[0024] In one embodiment of the present invention, the urethane resin preferably contains hydroxyl groups at least in the side chains. Introduction of hydroxyl groups into the side chains can be achieved, for example, by using a polyamine having hydroxyl groups (e.g., aminoethylethanolamine) as the polyamine chain extender and carrying out a chain extension reaction using only the highly reactive amino groups. The hydroxyl value of the urethane resin is 10 to 45 mgKOH / g, preferably 26 to 40 mgKOH / g, and more preferably 26 to 35 mgKOH / g from the viewpoint of cutting properties and ink stability. If the hydroxyl value is less than 10 mgKOH / g, the printability and cutting properties of the resulting printed layer will be poor, whereas if the hydroxyl value is more than 45 mgKOH / g, the ink stability will be poor. When the hydroxyl value is equal to or greater than the lower limit of the above range, the printability, cutability, and substrate adhesion of the resulting printed layer are improved.When the hydroxyl value is equal to or less than the upper limit of the above range, the printability, ink stability of the gravure ink composition, and cutability of the resulting printed layer are improved. The hydroxyl value of the urethane resin can be measured in accordance with JIS K0070-1992. The hydroxyl value of the urethane resin can be adjusted by the amount of the hydroxyl-containing polyamine used.

[0025] When the urethane resin contains an amino group, the amine value is preferably 0.1 to 20 mgKOH / g, more preferably 0.1 to 5 mgKOH / g, and from the viewpoint of substrate adhesion and ink stability, even more preferably 0.2 to 2 mgKOH / g. When the amine value is at least the lower limit of the above range, the substrate adhesion of the resulting printed layer is improved, and when the amine value is at most the upper limit of the above range, the ink stability of the gravure ink composition is improved. The amine value of the urethane resin is measured by potentiometric titration (e.g., COMTITE (AUTOTITRATOR COM-900, BURETB-900, TITSTATION K-900), manufactured by Hiranuma Sangyo Co., Ltd.) and then converted into the equivalent amount of potassium hydroxide.

[0026] <Difunctional polyisocyanate> A bifunctional polyisocyanate is a compound that has two isocyanate groups in one molecule. Bifunctional polyisocyanates function as curing agents. Examples of bifunctional polyisocyanates include reaction products of diisocyanate compounds and diol compounds, diisocyanate dimers, and allophanate-modified products, and these diisocyanate-modified products are preferred in terms of cutting properties, storage stability, residual solvents, and toxicity. Furthermore, as long as the physical properties are not affected, isocyanates other than bifunctional polyisocyanates can be used in combination, and commercially available products (with a functionality of less than 3) containing a certain amount of non-bifunctional by-products can also be used.

[0027] Examples of diisocyanate compounds include aliphatic diisocyanates, alicyclic diisocyanates, and aromatic diisocyanates among the polyisocyanate compounds described for the urethane resin. Aliphatic diisocyanates and alicyclic diisocyanates are preferred, and aliphatic diisocyanates are more preferred. Among aliphatic diisocyanates, isophorone diisocyanate, 1,5-pentamethylene diisocyanate, and hexamethylene diisocyanate are preferred, and hexamethylene diisocyanate is particularly preferred. One type of diisocyanate compound may be used alone, or two or more types may be used in combination.

[0028] Examples of diol compounds include ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, 1,2-propanediol, 1,3-propanediol, 2-methyl-1,3-propanediol, 2,2-dimethyl-1,3-propanediol, 2-methyl-2-propyl-1,3-propanediol, 2-ethyl-2-butyl-1,3-propanediol, 1,3-butanediol, 1,4-butanediol, and 1,5-pentanediol. Examples of the diol compound include saturated or unsaturated diol compounds such as 2,2-dimethyl-1,3-propanediol, 3-methyl-1,5-pentanediol, 1,6-hexanediol, neopentyl glycol, pentanediol, 3-methyl-1,5-pentanediol, octanediol, 1,9-nonanediol, 1,8-nonanediol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, 2,2-dimethyl-1,3-propanediol monohydroxypivalate, bisphenol A, and hydrogenated bisphenol A. One type of diol compound may be used alone, or two or more types may be used in combination.

[0029] (Physical properties of bifunctional polyisocyanates) The content of isocyanate groups relative to the total mass of the bifunctional polyisocyanate is 15.0 to 35.0 mass%, preferably 15.0 to 30.0 mass%, and more preferably 15.0 to 25.0 mass% from the viewpoint of ink stability and cutting ability. When the isocyanate group content is within the above range, the ink can achieve both stability over time and cutting ability. If the isocyanate group content is less than 15.0% by mass, cutting ability is poor, and if it exceeds 35.0% by mass, ink stability is reduced.

[0030] The isocyanate group content, i.e., the NCO content (mass%), can be determined by neutralizing the isocyanate groups in a measurement sample with an excess of 2N amine and then back titrating with 1N hydrochloric acid. When the bifunctional polyisocyanate to be measured contains an organic solvent (when the product contains an organic solvent), the measurement is performed on the solid content from which the volatile components have been removed. In this specification, the term "solid content" refers to the residue remaining after heating and drying the measurement target (e.g., 1 g) in a circulating air dryer at 130°C for 45 minutes.

[0031] The viscosity of the bifunctional polyisocyanate at 25°C is preferably 100 to 3,000 mPa·s, more preferably 100 to 2,500 mPa·s, and even more preferably 100 to 2,000 mPa·s from the viewpoint of stability and compatibility. The viscosity of the bifunctional polyisocyanate at 25°C can be measured using a B-type viscometer.

[0032] Commercially available bifunctional polyisocyanates may be used. Examples of commercially available products include those manufactured by Asahi Kasei Corporation under the trade names "Duranate D101," "Duranate D201," and "Duranate A201H," and those manufactured by Sumika Covestro Urethane Co., Ltd. under the trade names "Desmodur N3400" and "Desmodur N31100." These bifunctional polyisocyanates are bifunctional polyisocyanates containing hexamethylene diisocyanate units. These may be used alone or in combination of two or more.

[0033] <Organic solvents> As the organic solvent, it is preferable to use a mixed solvent consisting of two or more organic solvents, and known organic solvents can be used, such as aromatic organic solvents such as toluene and xylene, ketone organic solvents such as methyl ethyl ketone and methyl isobutyl ketone, ester organic solvents such as ethyl acetate, n-propyl acetate, isopropyl acetate, isobutyl acetate, and alcohol organic solvents such as methanol, ethanol, n-propanol, isopropanol, and n-butanol. Among these, organic solvents that do not contain aromatic organic solvents such as toluene and xylene (non-toluene organic solvents) are more preferred.

[0034] <Other ingredients> The gravure ink composition of this embodiment may contain other components in addition to the urethane resin, the bifunctional polyisocyanate, and the organic solvent. Examples of other components include other resins other than the urethane resin, other polyisocyanates other than the bifunctional polyisocyanates (i.e., tri- or higher functional polyisocyanates, curing agents), pigments, and additives.

[0035] Examples of the other resins include vinyl chloride-vinyl acetate copolymer, chlorinated polypropylene, cellulose-based resin, ethylene-vinyl acetate copolymer, vinyl acetate resin, polyamide, acrylic resin, polyester resin, alkyd resin, polyvinyl chloride, rosin-based resin, rosin-modified maleic acid resin, terpene resin, phenol-modified terpene resin, ketone resin, cyclized rubber, chlorinated rubber, butyral, petroleum resin, and modified resins thereof. The use of these resins can improve the blocking resistance of the resulting printed layer. These resins may be used alone or in combination of two or more. When the gravure ink composition of this embodiment contains other resins, particularly vinyl chloride-vinyl acetate copolymer, cellulose-based resin, acrylic resin, or polyester resin, the resulting printed layer (5 cm x 5 cm) can be laminated with a pressure of 7 kgf / cm, with the surface of the substrate film being in contact with the surface of the printed layer. 2When the laminated piece was peeled off after being stored under conditions of 40°C and 80% relative humidity for 24 hours under a load of 1000 kJ / s, the printed layer did not peel off and there was no peel resistance.

[0036] Examples of the other polyisocyanates include trifunctional or higher polyisocyanates. The use of the other polyisocyanates can improve the cutting properties and substrate adhesion of the resulting printed layer, as well as the ink stability of the gravure ink composition. The other polyisocyanates may be used alone or in combination of two or more. When the gravure ink composition of this embodiment contains the other polyisocyanate, it is preferable that the other polyisocyanate contains a trifunctional polyisocyanate.

[0037] Examples of the additives include dispersants, leveling agents, antifoaming agents, waxes, antiblocking agents, plasticizers, light stabilizers, infrared absorbers, ultraviolet absorbers, fragrances, and flame retardants.

[0038] (Vinyl chloride-vinyl acetate copolymer) Vinyl chloride-vinyl acetate copolymer is a copolymerization reaction product of vinyl chloride and vinyl acetate. That is, the vinyl chloride-vinyl acetate copolymer contains vinyl chloride units and vinyl acetate units. Furthermore, the vinyl chloride-vinyl acetate copolymer may contain units of a monomer (another monomer) other than the vinyl chloride units and vinyl acetate units, as necessary. The other monomer is not particularly limited as long as it is copolymerizable with vinyl chloride and vinyl acetate.

[0039] The vinyl chloride-vinyl acetate copolymer may have a group capable of reacting with an isocyanate group. The group capable of reacting with an isocyanate group is preferably a hydroxyl group. A vinyl chloride-vinyl acetate copolymer having a hydroxyl group can be obtained, for example, by saponifying a portion of the acetate moiety.

[0040] When the vinyl chloride-vinyl acetate copolymer contains hydroxyl groups, the hydroxyl value is preferably 50 to 250 mgKOH / g, more preferably 60 to 200 mgKOH / g, and from the viewpoint of substrate adhesion and ink stability, even more preferably 80 to 180 mgKOH / g. When the hydroxyl value is at least the lower limit of the above range, the adhesion to the substrate is improved, and when the hydroxyl value is at most the upper limit of the above range, the ink stability of the gravure ink composition is improved. The hydroxyl value of the vinyl chloride-vinyl acetate copolymer can be measured in accordance with JIS K0070-1992.

[0041] The content of vinyl chloride units relative to the total mass of the vinyl chloride-vinyl acetate copolymer is preferably 80 to 95 mass%, more preferably 88 to 93 mass%. When the content of vinyl chloride units is within this range, the adhesion of the resulting printing layer to the substrate is improved.

[0042] The content of vinyl acetate units relative to the total mass of the vinyl chloride-vinyl acetate copolymer is preferably 1 to 20 mass%, more preferably 1 to 15 mass%. When the content of vinyl acetate units is within this range, the adhesion of the resulting printing layer to the substrate is improved.

[0043] (cellulose resin, acrylic resin, polyester resin) As the cellulose-based resin, acrylic resin, and polyester resin, resins known in the art can be used.

[0044] The cellulose-based resin, acrylic resin, and polyester resin may have a group capable of reacting with an isocyanate group, preferably a hydroxyl group.

[0045] When the cellulose-based resin contains hydroxyl groups, the hydroxyl value is preferably 20 to 250 mgKOH / g, more preferably 30 to 200 mgKOH / g, and from the viewpoint of improving compatibility, even more preferably 40 to 170 mgKOH / g. When the acrylic resin contains hydroxyl groups, the hydroxyl value is preferably 10 to 110 mgKOH / g, more preferably 20 to 80 mgKOH / g, and from the viewpoint of improving compatibility, even more preferably 20 to 50 mgKOH / g. When the polyester resin contains hydroxyl groups, the hydroxyl value is preferably 10 to 110 mgKOH / g, more preferably 20 to 80 mgKOH / g, and from the viewpoint of improving compatibility, even more preferably 30 to 60 mgKOH / g. The hydroxyl value of the cellulose-based resin, acrylic resin, and polyester resin can be measured in accordance with JIS K0070-1992.

[0046] (trifunctional polyisocyanate) Trifunctional polyisocyanates are compounds that contain three isocyanate groups in one molecule. They function as curing agents. As the trifunctional polyisocyanate, any trifunctional polyisocyanate known in the art can be used, and examples thereof include compounds having three isocyanate groups exemplified as the polyisocyanate compounds described above, and adducts, isocyanurates, and biurets of the bifunctional polyisocyanates described above.

[0047] As the trifunctional polyisocyanate, commercially available products may be used. Examples of commercially available products include those sold under the trade names "Takenate D103," "Takenate D160N," "Takenate D170N," ​​"Takenate D110N," "Takenate D132N," and "Takenate D140N" manufactured by Mitsui Chemicals, Inc. One of these may be used alone, or two or more may be used in combination.

[0048] (pigment) Examples of pigments include inorganic pigments, organic pigments, and extender pigments. Examples of inorganic pigments include titanium oxide, zinc oxide, zinc sulfide, barium sulfate, silica, aluminum, calcium carbonate, chromium oxide, red iron oxide, and mica. One type of inorganic pigment may be used alone, or two or more types may be used in combination. Titanium oxide is particularly desirable from the viewpoint of hiding power. Titanium oxide pigments having a rutile crystal structure are preferred. The surface of the titanium oxide pigment is preferably treated with silica and / or alumina. The presence of a silica and / or alumina treatment layer improves the printability of gravure ink. Titanium oxide pigments may also be treated with other metals or oxides, such as simple metals such as Si, Al, Zn, or Zr, or oxides of Al and Zn. The term "treated" in the context of titanium oxide refers to a state in which the surface of the titanium oxide particles is coated. The titanium oxide preferably has an oil absorption of 14 to 40 mL / 100 g, more preferably 17 to 30 mL / 100 g, as measured by the JIS K5101 standard. The average particle size (median particle size) measured by a transmission electron microscope is preferably 0.15 μm to 0.35 μm, and more preferably 0.20 to 0.30 μm.

[0049] Examples of extender pigments include calcium carbonate, magnesium carbonate, barium carbonate, calcium sulfate, barium sulfate, silica, talc, kaolin, and mica. One type of extender pigment may be used alone, or two or more types may be used in combination. Examples of silica include sodium silicate, silicon tetrachloride, calcium silicate, and aluminum silicate. From the viewpoint of improving blocking resistance, printability, and residual solvent, it is preferable to contain silica. Surface-treated silica is more preferable.

[0050] Examples of organic pigments include pigments commonly used in gravure ink compositions, such as soluble azo pigments, insoluble azo pigments, phthalocyanine pigments, quinacridone pigments, isoindolinone pigments, isoindoline pigments, perylene pigments, perinone pigments, dioxazine pigments, anthraquinone pigments, dianthraquinonyl pigments, anthrapyrimidine pigments, anthanthrone pigments, indanthrone pigments, flavanthrone pigments, pyranthrone pigments, and diketopyrrolopyrrole pigments. These pigments can be used alone or in combination of two or more.

[0051] As the pigment, a plurality of types of titanium oxide pigments may be used in combination. In addition to the titanium oxide pigment, other inorganic pigments and organic pigments can also be used in the gravure ink composition of this embodiment.

[0052] <Medium, gravure ink> A composition obtained by adding silica to the gravure ink composition of this embodiment is called a medium. A composition obtained by adding a pigment to the gravure ink composition of this embodiment is called a gravure ink. That is, the gravure ink composition of the present invention can be suitably used as a medium for gravure ink or toning. However, the use of the medium is not limited to toning, and its use as a varnish is also a preferred embodiment. For example, in a laminate having a printed layer formed from the gravure ink, the printed layer has excellent cutting properties. Furthermore, the medium has excellent printability for the gravure ink after toning, and in a laminate having a printed layer formed from the gravure ink or varnish, the printed layer has excellent blocking resistance, residual solvent resistance, and cutting properties.

[0053] <Composition of gravure ink composition (medium, gravure ink)> The solid content of the urethane resin relative to the total mass of the gravure ink composition is preferably 4 to 15 mass%, more preferably 5 to 13 mass%, and even more preferably 6 to 11 mass%. When the urethane resin content is within this range, the adhesion of the resulting printing layer to the substrate and the ink stability of the gravure ink composition are improved. The content of the urethane resin solids relative to the total mass of the solids in the gravure ink composition is 10 to 65 mass%, preferably 10 to 55 mass%, more preferably 13 to 50 mass%, and even more preferably 15 to 45 mass%. When the urethane resin content is within this range, the substrate adhesion of the resulting printed layer and the ink stability of the gravure ink composition are improved. When the urethane resin solids content relative to the total mass of the solids in the gravure ink composition is less than 10 mass%, the substrate adhesion is poor. On the other hand, when the solids content exceeds 65 mass%, the blocking resistance and ink stability are poor.

[0054] The solid content of the bifunctional polyisocyanate relative to the total mass of the gravure ink composition is preferably 0.6 to 2.7 mass%, more preferably 0.7 to 2.6 mass%, and even more preferably 0.8 to 2.5 mass%. When the content of the bifunctional polyisocyanate is within this range, the cuttability and substrate adhesion of the resulting printing layer, as well as the ink stability of the gravure ink composition, are improved. The content of the bifunctional polyisocyanate solids relative to the total mass of the solids in the gravure ink composition is preferably 1.5 to 13.5 mass%, more preferably 1.5 to 11.5 mass%, and even more preferably 1.5 to 11.0 mass%. When the content of the bifunctional polyisocyanate is within this range, the cuttability and substrate adhesion of the resulting printing layer, as well as the ink stability of the gravure ink composition, are improved.

[0055] The content of the pigment relative to the total mass of the gravure ink composition is preferably 5 to 50 mass % of the solid content, more preferably 5 to 45 mass %, and even more preferably 5 to 40 mass %. The content of the solid content of the pigment relative to the total mass of the solid content of the gravure ink composition is preferably 15 to 70 mass %, more preferably 20 to 70 mass %, and even more preferably 25 to 70 mass %.

[0056] The content of silica relative to the total mass of the gravure ink composition (medium) is preferably 0.1 to 2.0 mass % of the solid content, more preferably 0.1 to 1.0 mass %, and even more preferably 0.2 to 0.6 mass %. The content of the solid content of the pigment relative to the total mass of the solid content of the gravure ink composition (medium) is preferably 0.2 to 5.0 mass%, more preferably 0.2 to 3.0 mass%, and even more preferably 0.4 to 2.5 mass%.

[0057] The content of the organic solvent relative to the total mass of the gravure ink composition is preferably 20 to 90 mass%, more preferably 40 to 85 mass%, and even more preferably 50 to 85 mass%. Note that, when the urethane resin or bifunctional polyisocyanate contains an organic solvent (when the product contains an organic solvent), the content of the organic solvent includes the amount of this organic solvent.

[0058] When the gravure ink composition contains other resins, the solid content of the other resins relative to the total mass of the gravure ink composition is preferably 1 to 9 mass%, and from the viewpoint of improving substrate adhesion and blocking resistance, it is more preferably 1 to 5 mass%. When the gravure ink composition contains other resins, the content of the solid content of the other resins relative to the total mass of the solid content of the gravure ink composition is preferably 3 to 30 mass%, more preferably 4 to 20 mass%.

[0059] When the gravure ink composition contains a vinyl chloride-vinyl acetate copolymer, the solid content of the vinyl chloride-vinyl acetate copolymer relative to the total mass of the gravure ink composition is preferably 1.0 to 6.0 mass%, more preferably 1.3 to 5.5 mass%, and even more preferably 1.5 to 5.0 mass%. When the content of the vinyl chloride-vinyl acetate copolymer is within the above range, the cuttability and substrate adhesion of the resulting printed layer are improved, and the ink viscosity is appropriate. When the gravure ink composition contains a vinyl chloride-vinyl acetate copolymer, the content of the vinyl chloride-vinyl acetate copolymer solids relative to the total mass of the solids of the gravure ink composition is preferably 3 to 30 mass%, more preferably 4 to 25 mass%, and even more preferably 4 to 20 mass%. When the content of the vinyl chloride-vinyl acetate copolymer is within the above range, the cuttability and substrate adhesion of the resulting printing layer are improved, and residual solvent is reduced.

[0060] When the gravure ink composition contains a cellulose-based resin, the solid content of the cellulose-based resin relative to the total mass of the gravure ink composition is preferably 0.1 to 10 mass%, and from the viewpoint of improving substrate adhesion and blocking resistance, it is more preferably 0.3 to 5 mass%. When the gravure ink composition contains a cellulose-based resin, the content of the solid content of the cellulose-based resin relative to the total mass of the solid content of the gravure ink composition is preferably 0.3 to 15 mass%, more preferably 0.5 to 10 mass%, and even more preferably 0.5 to 5 mass%. When the solid content of the cellulose resin relative to the total mass of the solid content of the gravure ink composition was less than 0.3 mass%, the peeled area in the substrate adhesion test in the Examples described below was 10 to 12%, and less than 10% of the printed layer peeled in the blocking resistance test in the Examples described below, and peel resistance was slight. When the solid content of the cellulose resin relative to the total mass of the solid content of the gravure ink composition was 0.3 mass% or more but less than 0.5 mass%, the peeled area in the substrate adhesion test was 12 to 15%, and less than 10% of the printed layer peeled in the blocking resistance test, and peel resistance was slight. When the solid content of the cellulose resin relative to the total mass of the solid content of the gravure ink composition was 0.5 to 5 mass%, the peeled area in the substrate adhesion test was 15 to 20%, and the printed layer did not peel in the blocking resistance test, and there was no peel resistance. When the solid content of the cellulose resin relative to the total mass of the solid content of the gravure ink composition was 5 to 10 mass%, the peeled area in the substrate adhesion test was 20 to 25%, and the printed layer did not peel in the blocking resistance test, and there was no peel resistance. When the solid content of the cellulose resin relative to the total mass of the solid content of the gravure ink composition was 10 to 15 mass%, the peeled area in the substrate adhesion test was 20 to 25%, and less than 10% of the printed layer peeled in the blocking resistance test, and the peel resistance was slight. When the solid content of the cellulose resin relative to the total mass of the solid content of the gravure ink composition was more than 15 mass%, the peeled area in the substrate adhesion test was 25 to 30%, and less than 10% of the printed layer peeled in the blocking resistance test, and the peel resistance was slight. Furthermore, regardless of the range of these contents, the evaluation results in the present invention were within the preferred range.

[0061] When the gravure ink composition contains a polyester resin, the solid content of the polyester resin relative to the total mass of the gravure ink composition is preferably 0.1 to 10 mass%, and from the viewpoint of improving substrate adhesion and blocking resistance, it is more preferably 0.3 to 5 mass%. When the gravure ink composition contains a polyester resin, the content of the solid content of the polyester resin relative to the total mass of the solid content of the gravure ink composition is preferably 0.3 to 15 mass%, more preferably 0.5 to 10 mass%, even more preferably 0.5 to 5 mass%, and particularly preferably 0.5 to 3 mass% from the viewpoint of improving substrate adhesion and blocking resistance.

[0062] When the gravure ink composition contains an acrylic resin, the solid content of the acrylic resin relative to the total mass of the gravure ink composition is preferably 0.1 to 10 mass%, and from the viewpoint of improving substrate adhesion and blocking resistance, it is more preferably 0.3 to 5 mass%. When the gravure ink composition contains an acrylic resin, the content of the solid content of the acrylic resin relative to the total mass of the solid content of the gravure ink composition is preferably 0.3 to 15 mass%, more preferably 0.5 to 10 mass%, even more preferably 0.5 to 5 mass%, and particularly preferably 0.5 to 3 mass% from the viewpoint of improving substrate adhesion and blocking resistance.

[0063] The content of solids of resins other than vinyl chloride-vinyl acetate copolymer, cellulose-based resin, polyester resin, and acrylic resin relative to the total mass of the gravure ink composition is preferably 0.5 mass% or less, more preferably 0.1 mass% or less, and particularly preferably zero. The content of solids of resins other than the vinyl chloride-vinyl acetate copolymer, cellulose resin, and polyester resin relative to the total mass of solids in the gravure ink composition is preferably 1 mass% or less, more preferably 0.2 mass% or less, and particularly preferably zero.

[0064] When the gravure ink composition contains a tri- or higher functional polyisocyanate, the solid content of the tri- or higher functional polyisocyanate relative to the total mass of the gravure ink composition is preferably 0.1 to 2.0 mass%, more preferably 0.1 to 1.8 mass%, even more preferably 0.1 to 1.5 mass%, even more preferably 0.1 to 1.2 mass%, and particularly preferably 0.1 to 0.7 mass%. When the tri- or higher functional polyisocyanate is within this range, the cuttability of the resulting printing layer and the ink stability of the gravure ink composition are improved. The solid content of the tri- or higher functional polyisocyanate relative to the total mass of the solids in the gravure ink composition is 0.5 to 10.0 mass%, more preferably 0.5 to 9.0 mass%, even more preferably 0.5 to 8.0 mass%, even more preferably 0.5 to 2.7 mass%, and particularly preferably 0.5 to 1.6 mass%. When the content of the tri- or higher functional polyisocyanate is within the above range, the cuttability of the resulting printing layer and the ink stability of the gravure ink composition are improved.

[0065] When the gravure ink composition further contains a trifunctional polyisocyanate, the content of the trifunctional polyisocyanate as solids relative to the total mass of the gravure ink composition is preferably 0.1 to 2.0 mass%, more preferably 0.1 to 1.8 mass%, even more preferably 0.1 to 1.5 mass%, even more preferably 0.1 to 1.2 mass%, and particularly preferably 0.1 to 0.7 mass%. When the content of the trifunctional polyisocyanate is within the above range, the cuttability of the resulting printing layer and the ink stability of the gravure ink composition are improved. The content of the trifunctional polyisocyanate solids relative to the total mass of the solids in the gravure ink composition is preferably 0.5 to 10.0 mass%, more preferably 0.5 to 9.0 mass%, even more preferably 0.5 to 8.0 mass%, even more preferably 0.5 to 2.7 mass%, and particularly preferably 0.5 to 1.6 mass%. When the content of the trifunctional polyisocyanate is within this range, the cuttability of the resulting printing layer and the ink stability of the gravure ink composition are improved.

[0066] The solid content of the tetrafunctional or higher polyisocyanate relative to the total mass of the gravure ink composition is preferably 1 mass % or less, more preferably 0.7 mass % or less, and even more preferably 0.3 mass % or less. The solid content of the tetrafunctional or higher polyisocyanate relative to the total mass of the solids in the gravure ink composition is preferably 5 mass % or less, more preferably 2 mass % or less, and even more preferably 1 mass % or less.

[0067] The mass ratio of the urethane resin to the bifunctional polyisocyanate (urethane resin:bifunctional polyisocyanate) is 13.0:1.0 to 3.0:1.0, preferably 12.0:1.0 to 3.0:1.0, and more preferably 11.0:1.0 to 3.0:1.0 from the viewpoint of cutting properties and ink stability. When the mass ratio is within the above range, the cutting properties of the resulting printed layer and the ink stability of the gravure ink composition are improved. Furthermore, if the ratio of the urethane resin in the mass ratio of 3.0:1.0 is less than 3.0, the effects will be inferior in terms of substrate adhesion and printability, while if the ratio of the urethane resin in the mass ratio of 13.0:1.0 is more than 13.0, the cuttability will be reduced. When the urethane resin and the bifunctional polyisocyanate contain an organic solvent (when the product contains an organic solvent), the mass ratio is the mass ratio between the solid contents after removing the volatile content.

[0068] When the gravure ink composition contains the other resins, the mass ratio of the urethane resin to the other resins (urethane resin:other resin) is preferably 1.0:0.10 to 1.0:1.0, more preferably 1.0:0.1 to 1.0:0.8, and from the viewpoints of blocking resistance and substrate adhesion, even more preferably 1.0:0.2 to 1.0:0.6. When the gravure ink composition contains a vinyl chloride-vinyl acetate copolymer, the mass ratio of the urethane resin to the vinyl chloride-vinyl acetate copolymer (urethane resin:vinyl chloride-vinyl acetate copolymer) is preferably 1.0:0.10 to 1.0:1.0, more preferably 1.0:0.2 to 1.0:0.8, and from the viewpoint of blocking resistance and residual solvent, even more preferably 1.0:0.2 to 1.0:0.6. When the mass ratio is within this range, ink stability and substrate adhesion are improved. When the gravure ink composition contains the other resins, the mass ratio of the total of the urethane resin and other resins to the polyisocyanate (including both difunctional and tri- or higher functional resins) (urethane resin + other resins: polyisocyanate) is 20.0:1.0 to 3.0:1.0, preferably 16.0:1.0 to 3.0:1.0, and more preferably 14.0:1.0 to 4.0:1.0 from the viewpoint of blocking resistance. When the gravure ink composition contains a vinyl chloride-vinyl acetate copolymer, the mass ratio of the total of the urethane resin and the vinyl chloride-vinyl acetate copolymer to the polyisocyanate (including both bifunctional and trifunctional or higher functional) (urethane resin + vinyl chloride-vinyl acetate copolymer:polyisocyanate) is 20.0:1.0 to 3.0:1.0, preferably 16.0:1.0 to 3.0:1.0, and more preferably 14.0:1.0 to 4.0:1.0 from the viewpoint of blocking resistance. When this mass ratio is within this range, the resulting printed layer exhibits improved cuttability and substrate adhesion, as well as improved ink stability of the gravure ink composition. Note that when the urethane resin, polyisocyanate, and vinyl chloride-vinyl acetate copolymer contain organic solvents (when the product contains organic solvents), the mass ratio is the mass ratio of the solids from which volatile components have been removed.

[0069] When the gravure ink composition contains a trifunctional or higher polyisocyanate, the mass ratio of the bifunctional polyisocyanate to the trifunctional or higher polyisocyanate (bifunctional polyisocyanate:trifunctional or higher polyisocyanate) is preferably 1.0:0.1 to 1.0:2.0, more preferably 1.0:0.1 to 1.0:1.6, more preferably 1.0:0.1 to 1.0:1.2, and even more preferably 1.0:0.1 to 1.0:0.7 from the viewpoint of residual solvent. A large amount of trifunctional or higher polyisocyanate leads to poor cutting properties and increased residual solvent. When the gravure ink composition does not contain a tetrafunctional or higher polyisocyanate, the above-mentioned bifunctional polyisocyanate:trifunctional or higher polyisocyanate ratio is interpreted as bifunctional polyisocyanate:trifunctional polyisocyanate. When the gravure ink composition contains a tri- or higher functional polyisocyanate, the mass ratio of the urethane resin to the sum of the difunctional polyisocyanate and tri- or higher functional polyisocyanate (urethane resin: difunctional polyisocyanate + tri- or higher functional polyisocyanate) is preferably 13.0:1.0 to 3.0:1.0, more preferably 12.0:1.0 to 3.0:1.0, and from the viewpoints of cutting ability, ink stability, and blocking resistance, even more preferably 11.0:1.0 to 3.0:1.0. Note that when the gravure ink composition does not contain a tetra- or higher functional polyisocyanate, the "urethane resin: difunctional polyisocyanate + tri- or higher functional polyisocyanate" is read as "urethane resin: difunctional polyisocyanate + trifunctional polyisocyanate." When the mass ratio is within the above range, the cutting ability and residual solvent are improved. In addition, when the difunctional polyisocyanate and tri- or higher functional polyisocyanate to be measured contain an organic solvent (when the product contains an organic solvent), the mass ratio is the mass ratio between the solid contents after removing the volatile components.

[0070] <Method for producing gravure ink composition (medium, gravure ink)> The gravure ink composition can be produced by mixing a binder resin composition containing a urethane resin with a curing agent composition containing a bifunctional polyisocyanate. The binder resin composition can be produced by dispersing a pigment in an organic solvent using a disperser along with a urethane resin and, if necessary, a vinyl chloride-vinyl acetate copolymer, and then mixing the resulting pigment dispersion with other resins, various additives, an organic solvent, etc. The curing agent composition can be produced by mixing a bifunctional polyisocyanate and, if necessary, other polyisocyanates and an organic solvent.

[0071] <Laminate> The laminate of this embodiment has a print layer formed from the medium or gravure ink of this embodiment. The laminate of this embodiment will be described below with reference to Fig. 1. Fig. 1 is a cross-sectional view showing the laminate of this embodiment.

[0072] As shown in FIG. 1, the laminate 10 of this embodiment has at least a first substrate 11, a printed layer 12, and a second substrate 14. The printed layer 12 is formed on one surface (upper surface) 11a of the first substrate 11. An adhesive layer 13 is formed on the surface (upper surface) 12a of the printed layer 12 opposite the surface that contacts the first substrate 11. A second substrate 14 is provided on the surface (upper surface) 13a of the adhesive layer 13 opposite the surface that contacts the printed layer 12. That is, the laminate 10 has the first substrate 11, the printed layer 12, the adhesive layer 13, and the second substrate 14 laminated in this order.

[0073] Examples of the first substrate 11 include polyester films such as polyethylene terephthalate (PET), polybutylene terephthalate (PBT), and polyethylene naphthalate (PEN); polyolefin films such as low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), high-density polyethylene (HDPE), and polypropylene (PP); cellulose films such as cellophane; polystyrene (PS) films; ethylene-vinyl acetate copolymer resin films; ethylene-vinyl alcohol copolymer resin films; polyamide films such as nylon (NY) film; polycarbonate films; polyimide films; and polyvinyl chloride films. Both stretched and unstretched plastic films, such as biaxially oriented PP films and unstretched PP films, can be used. Substrates with a metal vapor deposition layer such as aluminum vapor deposition and transparent vapor deposition layers such as alumina and silica can also be used. Furthermore, the surface of the substrate may be subjected to various surface treatments such as corona discharge treatment, plasma treatment, flame treatment, solvent treatment, and coating treatment, as well as various decorations such as printing with colored inks.

[0074] Examples of the second substrate 14 include polyethylene, polypropylene, and other polyolefin substrates, or film-like sealants made of composite materials thereof. Examples of methods for laminating the resin layer include known lamination methods such as dry lamination, in which another plastic film (resin layer) is laminated via an adhesive layer on a printed layer provided on a plastic film, and extrusion lamination, in which a molten resin is laminated, if necessary, via an anchor coating agent layer. The thickness of the resin layer is, for example, preferably 1 to 300 μm, more preferably 5 to 200 μm, and particularly preferably 10 to 100 μm.

[0075] The adhesive layer 13 is formed by applying and drying an adhesive. A suitable adhesive is a two-component adhesive made of a mixture of polyol and an isocyanate curing agent. Examples of polyols include polyester-based and polyether-based adhesives. Specific examples include TM-250HV / CAT-RT86L-60, TM-550 / CAT-RT37, and TM-314 / CAT-14B manufactured by Toyo-Morton Co., Ltd.

[0076] <Method of manufacturing laminate> The laminate of this embodiment is obtained by printing a medium or gravure ink on the upper surface 11a of the first substrate 11 to form a printed layer 12, forming an adhesive layer 13 on the upper surface 12a of the printed layer 12, and bonding (laminating) the first substrate 11 and the second substrate 14 together via the adhesive layer 13. Examples of lamination methods that can be used include dry lamination, which involves applying an adhesive to the print layer of a printed material or to a sealant, drying the adhesive, and then laminating the printed material and the sealant by pressure bonding.

[0077] According to the laminate 10 of this embodiment, the printed layer 12 is formed from a medium or gravure ink containing the gravure ink composition of this embodiment as the medium or gravure ink, and therefore the printed layer has better cutting properties than when conventional medium or gravure ink is used.

[0078] <Application> The laminate 10 is preferably used as a packaging material. The packaging material is preferably a packaging material for flexible packaging. "Flexible packaging" refers to packaging material made of a flexible material, i.e., a flexible package, and is used to package food, daily necessities, etc.

[0079] <Mechanism of action> The gravure ink composition of the present invention contains a bifunctional polyisocyanate. Compared to trifunctional polyisocyanates, bifunctional polyisocyanates have fewer crosslinking points that can crosslink with polyurethane resins. Therefore, compared to trifunctional polyisocyanates, three-dimensional crosslinking is less likely to proceed, resulting in a crosslinked body (printed layer) with a relatively sparse structure. As a result, the adhesive described above is more likely to penetrate into the printed layer, improving cutting properties. Note that, as shown in the above examples, cutting properties may be improved depending on the type of trifunctional polyisocyanate. However, in this case, the problem of increased residual solvent may occur. [Example]

[0080] The present invention will be explained in more detail below with reference to examples and comparative examples, but the present invention is not limited to the following examples.

[0081] <Evaluation method> (Cutting ability) The laminates of the examples and comparative examples were evaluated for cuttability by a sensory test in which an incision was made with a cutter at the edge of the printed portion in a direction perpendicular to the printing, and the laminate was torn by hand. The evaluation criteria were as follows, with A to C being considered acceptable. A: It can be cut without resistance. B: There is a slight resistance, but it cuts. C: There is resistance but it cuts. D: Strong resistance, stretches while breaking. E: LLDPE stretches and cannot be cut.

[0082] (Ink stability) The viscosity (V1) of the gravure ink composition immediately after mixing the binder resin composition and the curing agent composition of the Examples and Comparative Examples, and the viscosity (V2) of the gravure ink composition after storing at 20°C for 24 hours were measured using a Zahn Cup #3 manufactured by Rigo Co., Ltd., and the viscosity increase (viscosity (V2) - viscosity (V1)) was calculated. The viscosity measurement temperature was 20°C. The ink stability was evaluated according to the following evaluation criteria. Ink stability is an index of the fluidity of the gravure ink composition, and the shorter the viscosity increase, i.e., the better the ink stability, the better the fluidity. The evaluation criteria were as follows, with A to C being considered acceptable. A: Viscosity increase is less than 1 second. B: Viscosity increase lasts for 1 second or more but less than 3 seconds. C: Viscosity increase lasts for 3 seconds or more but less than 5 seconds. D: Viscosity increase lasts for 5 seconds or more but less than 10 seconds. E: Viscosity increase lasts for 10 seconds or more.

[0083] (Adhesion to substrate) Cellophane adhesive tape (manufactured by Nichiban Co., Ltd., width 18 mm) was applied to the printed layer of the printed matter of the Examples and Comparative Examples, and then the cellophane adhesive tape was peeled off and the adhesion of the printed layer to the substrate was evaluated according to the following criteria. The evaluation criteria were as follows, with A to C being considered acceptable. A: Peeling area less than 10%. B: Peeling area is 10% or more but less than 30%. C: Peeling area is 30% or more but less than 50%. D: Peeling area is 50% or more but less than 90%. E: Peeling area is 90% or more.

[0084] (printability) Using a gradation plate, the gravure ink compositions of the Examples and Comparative Examples were printed on a 25 μm thick PET film (manufactured by Toyobo Co., Ltd.) at a speed of 100 m / min. The printed matter was visually observed to confirm the presence of highlights and evaluate blurring. The evaluation criteria were as follows, with A to B being considered a pass. A: The cassoulet was not noticeable at all. B: Blurring was observed in 5% or more but less than 10% of the cells. C: Blurring was observed in 10% or more but less than 20% of the cells. D: Blurring was observed in more than 20% of the cells.

[0085] (residual solvent) The gravure ink compositions of the Examples and Comparative Examples were printed on a 12 μm thick PET film (manufactured by Toyobo Co., Ltd.), and the resulting printed layer was cut into a size of 10 cm wide x 15 cm long. Three of these pieces were placed in an Erlenmeyer flask, sealed, and heated (temperature: 80°C, 30 minutes). 1.0 ml of air was then removed from the flask and analyzed by gas chromatography (GC) to confirm the amount of solvent content. The evaluation criteria were as follows, with A to C being considered acceptable. A: The total amount of residual solvent is 2 mg / m 2 It was less than. B: The total amount of residual solvent is 2 mg / m 2 More than 4mg / m 2 It was less than. C: The total amount of residual solvent is 4 mg / m 2 More than 6mg / m 2 It was less than. D: The total amount of residual solvent is 6 mg / m 2 More than 8mg / m 2 It was less than. E: The total amount of residual solvent is 8 mg / m 2 That was all.

[0086] (blocking resistance) The printed matter of each of the examples and comparative examples was cut to prepare test pieces measuring 5 cm x 5 cm. The prepared test pieces were then stacked so that the surface of the printed layer and the surface of the base film were in contact with each other to obtain a laminated test piece. 2 The laminated test piece was peeled off and the state of the printed layer was observed, and the peel resistance was confirmed, and the blocking resistance was evaluated according to the following evaluation criteria. The evaluation criteria were as follows, with A to C being considered acceptable. A: The printed layer did not peel off and there was no peeling resistance. B: Less than 10% of the printed layer peeled off, and there was slight peel resistance. C: 10% or more but less than 30% of the printed layer peeled off, and there was peel resistance. D: 30% or more but less than 50% of the printed layer peeled off, and there was strong peel resistance. E: 50% or more of the printed layer peeled off, and there was fairly strong peel resistance.

[0087] <Raw materials used> The compounds shown below were used as the urethane resin (A) and other resin (a). A1: Urethane resin (Mw=69000, hydroxyl value=12mgKOH / g). A2: Urethane resin (Mw=42000, hydroxyl value=34mgKOH / g). A3: Urethane resin (Mw=71000, hydroxyl value=5mgKOH / g). A4: Urethane resin (Mw=37000, hydroxyl value=55mgKOH / g). a1: Vinyl chloride-vinyl acetate copolymer (trade name "Solvine TA5R", Mw = 61,000, hydroxyl value = 170 mg KOH / g (manufactured by Nissin Chemical Industry Co., Ltd.) a2: Cellulose-based resin (nitrocellulose, hydroxyl value = approx. 142 mg KOH / g). a3: Cellulose-based resin (cellulose acetate butyrate, hydroxyl value = approx. 43 mg KOH / g). a4: Cellulose-based resin (cellulose acetate propionate, hydroxyl value = approximately 86 mg KOH / g). a5: Polyester resin (hydroxyl value = approx. 39 mg KOH / g). · a6: Acrylic resin (hydroxyl value = approx. 22 mg KOH / g).

[0088] The following compounds were used as the bifunctional polyisocyanate (B) and the trifunctional polyisocyanate (b). B1: HDI-based bifunctional polyisocyanate (isocyanate group content: 19.7% by mass, viscosity: 500 mPa·s, manufactured by Asahi Kasei Corporation, product name "Duranate D101"). B2: HDI-based bifunctional polyisocyanate (isocyanate group content: 15.8% by mass, viscosity: 1800 mPa·s, manufactured by Asahi Kasei Corporation, product name "Duranate D201"). B3: HDI-based bifunctional polyisocyanate (isocyanate group content: 17.2 mass%, viscosity: 110 mPa·s, manufactured by Asahi Kasei Corporation, product name "Duranate A201H"). b1: TDI-based adduct trifunctional polyisocyanate (isocyanate group content: 17.3 mass%, viscosity: 800 mPa·s, manufactured by Mitsui Chemicals, Inc., trade name "Takenate D103"). b2: HDI-based adduct trifunctional polyisocyanate (isocyanate group content: 16.8 mass%, viscosity: 260 mPa·s, manufactured by Mitsui Chemicals, Inc., trade name "Takenate D160N"). b3: HDI-based nurate trifunctional polyisocyanate (isocyanate group content: 20.7 mass%, viscosity: 2000 mPa·s, manufactured by Mitsui Chemicals, Inc., product name "Takenate D170N"). b4: XDI-based adduct trifunctional polyisocyanate (isocyanate group content: 15.3 mass%, viscosity: 500 mPa·s, manufactured by Mitsui Chemicals, Inc., product name "Takenate D110N"). b5: XDI-based nurate trifunctional polyisocyanate (isocyanate group content: 19.3 mass%, viscosity: 110 mPa·s, manufactured by Mitsui Chemicals, Inc., product name "Takenate D132N"). b6: IPDI-based adduct trifunctional polyisocyanate (isocyanate group content: 14.0 mass%, viscosity: 2500 mPa·s, manufactured by Mitsui Chemicals, Inc., product name "Takenate D140N").

[0089] As the pigment (C), the following compound was used. C1: Titanium oxide: Product name "Titanix JR-806" (manufactured by Teika Corporation). C2: Copper phthalocyanine blue: (manufactured by Dainichiseika Color & Chemicals Mfg. Co., Ltd., CI Name "PB-15:3").

[0090] As the organic solvent (D), the following compound was used. D1: A mixed solvent of ethyl acetate, methyl ethyl ketone, and isopropyl alcohol (mass ratio = ethyl acetate:methyl ethyl ketone:isopropyl alcohol = 4:4:2)

[0091] [Examples 1 to 27, Comparative Examples 1 to 16] (Preparation of Gravure Ink) A binder resin composition was prepared by mixing a urethane resin (A), another resin (a), a pigment (C), and an organic solvent (D) and dispersing the mixture in a bead mill. A curing agent composition was prepared by mixing a difunctional polyisocyanate (B), a trifunctional polyisocyanate (b), and ethyl acetate. A gravure ink composition was prepared by mixing a binder resin composition and a curing agent composition. The amounts of the urethane resin (A), other resin (a), pigment (C), organic solvent (D), bifunctional polyisocyanate (B), and trifunctional polyisocyanate (b) were as shown in Tables 1 to 3. The amounts of the urethane resin (A), other resin (a), pigment (C), bifunctional polyisocyanate (B), and trifunctional polyisocyanate (b) refer to solid contents. The amount of organic solvent (D1) refers to the total amount of organic solvents added during preparation of the binder resin composition and curing agent composition, and the amount of organic solvent (D2) refers to the total amount of volatile components (organic solvents) contained in the product of the above-mentioned urethane resin (A), bifunctional polyisocyanate (B), and trifunctional polyisocyanate (b). The numerical values ​​for the gravure ink compositions in Tables 1 to 3 represent parts by mass, and blank spaces represent 0. In Tables 1 to 3, (A) / (B) represents the mass ratio of the solid content of the urethane resin to the solid content of the difunctional polyisocyanate. In addition, in terms of the solid content, (A) represents the content of the solid content of the urethane resin relative to the total mass of the solid content of the gravure ink composition, (a) represents the content of the solid content of other resins relative to the total mass of the solid content of the gravure ink composition, and (b) represents the content of the solid content of the trifunctional polyisocyanate relative to the total mass of the solid content of the gravure ink composition.

[0092] (Preparation of Laminate) A corona discharge-treated PET film (product name "Ester E5102", manufactured by Toyobo Co., Ltd., thickness 12 μm) was prepared as the substrate film. Using a Helio 175 line gravure plate, a gravure ink composition was applied to the treated surface of the substrate film by gravure printing to form a print layer, thereby obtaining a printed material. A dry laminating adhesive (Dainichiseika Chemicals "Seikabond E-593 / C-77" in a dry application amount of 3 g / m) was applied to the obtained printed material. 2 The laminate was coated and dried by gravure printing so that the coating became as shown in Table 1. The laminate was then thermocompressed with LLDPE (manufactured by Futamura Chemical Co., Ltd., trade name "LLXMTN") and aged at 40°C for 48 hours to obtain a laminate. The evaluation results are shown in Tables 1 to 3.

[0093] [Table 1]

[0094] [Table 2]

[0095] [Table 3]

[0096] As shown in Tables 1 to 3, the laminates formed from the gravure ink compositions of Examples 1 to 27 had high cutability and satisfied other physical properties required of a gravure ink composition. The laminates formed from the gravure ink compositions of Comparative Examples 2 to 5, 7, 8, 10 to 13, and 15 had poor cutability. The laminate formed from the gravure ink composition of Comparative Example 1 had high cutability, but a large amount of organic solvent remained in the printed layer, failing to satisfy the physical properties required of a gravure ink composition. The laminate formed from the gravure ink composition of Comparative Example 6 had high cutability, but the ink stability of the gravure ink composition was low, resulting in poor printability and a large amount of organic solvent remaining in the printed layer, failing to satisfy the physical properties required of a gravure ink composition. The laminate formed from the gravure ink composition of Comparative Example 9 had high cutability, but the printed layer had low substrate adhesion and poor printability, failing to satisfy the physical properties required of a gravure ink composition. The laminates formed from the gravure ink compositions of Comparative Examples 14 and 16 had high cutability, but the ink stability of the gravure ink compositions was low, and they did not satisfy the physical properties required of a gravure ink composition. Furthermore, when Examples 1 and 2, which differ only in urethane resin, were compared, the cutting ability was evaluated similarly for Examples 1 and 2 (there was a slight resistance, but it could be cut), but Example 2, which had a higher hydroxyl value, had better cutting ability. In Examples 11 to 13, in which a trifunctional polyisocyanate was further added to Example 5, the amount of organic solvent remaining in the printing layer increased as the amount of trifunctional polyisocyanate added increased (Example 11 → 13). Comparing Example 2 and Example 14, which differ only in the presence or absence of other resin (a), Example 2, which contains other resin (a), was superior in the evaluations of ink stability, substrate adhesion, printability, and residual solvent. Furthermore, Examples 15 to 18, which contain cellulose-based resin, were all rated B for substrate adhesion, but Example 15, which contained the highest cellulose-based resin content, had a slightly larger peel area than Examples 16 to 18. On the other hand, Example 18, which contained the lowest cellulose-based resin content, had slightly inferior blocking resistance compared to Examples 15 to 17.

[0097] [Reference Example] In Examples 1 to 27, Reference Examples 1A to 27A, which were gravure ink compositions containing silica but not containing other resin (a) or pigment (C), respectively, achieved the same effects as Examples 1 to 27. In Comparative Examples 1 to 16, Reference Comparative Examples 1A to 16A, which were gravure ink compositions containing silica but not containing other resin (a) or pigment (C), respectively, were inferior in evaluation results to Reference Examples 1A to 27A, similar to Comparative Examples 1 to 16, respectively. In Examples 1 to 27, Reference Examples 1B to 27B, which were gravure ink compositions containing a pigment and silica but not other resin (a), achieved the same effects as Examples 1 to 27. In Comparative Examples 1 to 16, Reference Comparative Examples 1B to 16B, which were gravure ink compositions containing a pigment and silica but not other resin (a), achieved evaluation results inferior to Reference Examples 1B to 27B, similar to Comparative Examples 1 to 16, respectively. [Industrial Applicability]

[0098] The gravure ink composition of the present invention is useful because it improves the cuttability of the resulting laminate and satisfies the physical properties required of a gravure ink composition. [Explanation of symbols]

[0099] 10 Laminate 11 First base material 12 printing layer 13 Adhesive layer 14 Second base material

Claims

1. A gravure ink composition comprising a urethane resin, an organic solvent, and a bifunctional polyisocyanate, and satisfying the following conditions (1) to (6): (1) The content of isocyanate groups relative to the total mass of the bifunctional polyisocyanate is 15.0 to 35.0 mass%. (2) The mass ratio of the urethane resin to the bifunctional polyisocyanate in terms of solid content is 13.0:1.0 to 3.0:1.

0. (3) The hydroxyl value of the urethane resin is 10 to 45 mgKOH / g. (4) The content of the solid content of the urethane resin relative to the total mass of the solid content of the gravure ink composition is 10 to 65 mass %. (5) When the gravure ink composition further contains another resin other than the urethane resin, the content of the solid content of the other resin relative to the total mass of the solid content of the gravure ink composition is 3 to 30 mass %, and the other resin other than the urethane resin contains at least one resin selected from the group consisting of vinyl chloride-vinyl acetate copolymer, cellulose-based resin, polyester resin, and acrylic resin, and when the gravure ink composition contains the vinyl chloride-vinyl acetate copolymer, the content of the solid content of the vinyl chloride-vinyl acetate copolymer relative to the total mass of the solid content of the gravure ink composition is 3 to 30 mass %, and when the gravure ink composition contains the cellulose-based resin, the content of the solid content of the cellulose-based resin relative to the total mass of the solid content of the gravure ink composition is 0.3 to 15 mass%; when the gravure ink composition contains the polyester resin, the content of the solid content of the polyester resin relative to the total mass of the solid content of the gravure ink composition is 0.3 to 15 mass%; when the gravure ink composition contains the acrylic resin, the content of the solid content of the acrylic resin relative to the total mass of the solid content of the gravure ink composition is 0.3 to 15 mass%; and the content of the solid content of resins other than the vinyl chloride-vinyl acetate copolymer, the cellulose-based resin, the polyester resin, and the acrylic resin relative to the total mass of the solid content of the gravure ink composition is 1 mass% or less. (6) When the gravure ink composition further contains a tri- or higher functional polyisocyanate, the content of the tri- or higher functional polyisocyanate in solid content relative to the total mass of the solid content of the gravure ink composition is 0.5 to 10 mass %.

2. 2. The gravure ink composition according to claim 1, wherein the other resin comprises a vinyl chloride-vinyl acetate copolymer, and the mass ratio of the urethane resin to the vinyl chloride-vinyl acetate copolymer in terms of solid content is 1.0:0.10 to 1.0:1.

0.

3. 3. The gravure ink composition according to claim 2, wherein the vinyl chloride-vinyl acetate copolymer has a hydroxyl group and a hydroxyl value of 50 to 250 mgKOH / g.

4. A medium comprising the gravure ink composition according to any one of claims 1 to 3 and silica.

5. A gravure ink comprising the gravure ink composition according to any one of claims 1 to 3 and a pigment.

6. A laminate having a print layer formed from the medium according to claim 4.

7. A laminate having a printing layer formed from the gravure ink according to claim 5.

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