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

Abstract

Provided are a gravure ink composition that improves the cuttability of the resulting laminate and satisfies the physical properties required for the gravure ink composition, and a laminate having a printed layer formed from the gravure ink composition. 【Solution means】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 in terms of solids content of the urethane resin to the bifunctional polyisocyanate is 13.0:1.0 to 3.0:1.0.

Description

Technical Field

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

Background Art

[0002] Conventionally, various packaging materials have been used to store liquids, powders, or solid foods, detergents, sundries, and the like. As such a packaging material, a packaging bag formed by bag-making a laminate having a plastic film (base material) as a main body and a printing layer formed using printing ink is known. The packaging bag is required to have strength from the viewpoint of protecting the contents. Further, the packaging bag is required to have excellent easy-openability (package cutting property, hereinafter also referred to as "cutting property") during use.

[0003] Patent Document 1 discloses that the cutting property of a laminate obtained by using a printing ink composition for lamination containing a pigment, a binder resin having a specific structure, a trifunctional isocyanate compound having an isocyanurate ring (hardener), and an organic solvent is improved.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, even when using the printing ink composition for lamination described in Patent Document 1, the cuttability of the resulting laminate is insufficient. In addition, the inventors of the present application have examined 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, although the cuttability may be improved depending on the type of trifunctional isocyanate compound, it has been found that the physical properties required for the gravure ink composition are not satisfied. Examples of the physical properties required for the gravure ink composition include the storage stability of the gravure ink composition (hereinafter, also referred to as "ink stability") and printability. In addition, for the printed layer obtained using the gravure ink or medium containing the gravure ink composition, high substrate adhesion and a small amount of residual organic solvent are also required.

[0006] The present invention has been made in view of the above circumstances, and provides a gravure ink composition in which the cuttability of the resulting laminate is improved and the physical properties required for the gravure ink composition are satisfied, a medium and a gravure ink containing the gravure ink composition, and a laminate having a printed layer formed from the medium and the gravure ink.

Means for Solving the Problems

[0007] In order to solve the above problems, the present invention has the following aspects. [1] A gravure ink composition containing 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 composition for gravure ink according to [1] or [2], wherein the weight average molecular weight of the urethane resin is 20,000 to 90,000. [4] The composition for gravure ink 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 composition for gravure ink according to [4], wherein the vinyl chloride-vinyl acetate copolymer has a hydroxyl group and the hydroxyl value is 50 to 250 mgKOH / g. [6] A medium containing the composition for gravure ink according to any one of [1] to [5] and silica. [7] A gravure ink containing the composition for gravure ink according to any one of [1] to [5] and a pigment. [8] A laminate having a printed layer formed from the medium according to [6]. [9] A laminate having a printed layer formed from the gravure ink according to [7].

[0008] [1A] A composition for gravure ink containing a urethane resin, an organic solvent, and a bifunctional polyisocyanate, and satisfying the following conditions (1) to (7). (1) The content of isocyanate groups with respect 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 with respect to the total mass of the solid content of the composition for gravure ink is 10 to 65% by mass. (6) When further containing other resins other than the urethane resin, the content of the solid content of the other resins with respect to the total mass of the solid content of the composition for gravure ink is 3 to 30% by mass. (7) When further containing a polyisocyanate having three or more functional groups, the content of the solid content of the polyisocyanate having three or more functional groups with respect to the total mass of the solid content of the gravure ink composition is 0.5 to 10% by mass. [2A] The gravure ink composition according to [1A], wherein the other resin is at least one selected from the group consisting of a vinyl chloride-vinyl acetate copolymer, a cellulose resin, a polyester resin, and an acrylic resin. [3A] The gravure ink composition according to [1A] or [2A], which contains a vinyl chloride-vinyl acetate copolymer as the other resin, 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 containing the gravure ink composition according to any one of [1A] to [4A] and silica. [6A] A gravure ink containing 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 printed layer formed from the gravure ink according to [6A]. [Effect of the Invention]

[0009] According to the present invention, it is possible to provide a gravure ink composition that improves the cutability of the obtained laminate and satisfies the physical properties required for the gravure ink composition, a medium and a gravure ink containing the gravure ink composition, and a laminate having a printed layer formed from the medium and the gravure ink. [Brief Description of the Drawings]

[0010]

Figure 1

Best Mode for Carrying Out the Invention

[0011] Hereinafter, embodiments of the present invention will be described in detail. 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 implemented with modifications within the scope of the gist thereof.

[0012] ≪Composition for Gravure Ink≫ The composition for gravure ink of the present 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 with respect 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 with respect to the total mass of the solid content of the composition for gravure ink is 10 to 65% by mass. (6) When further containing other resins other than the urethane resin, the content of the solid content of the other resins with respect to the total mass of the solid content of the composition for gravure ink is 3 to 30% by mass. (7) When further containing a polyisocyanate having three or more functional groups, the content of the solid content of the polyisocyanate having three or more functional groups with respect to the total mass of the solid content of the composition for gravure ink is 0.5 to 10% by 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. As the urethane resin, a reaction product of a polyisocyanate compound and a polyol compound can be cited as an example. Further, 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 performing a chain extension reaction using a chain extender can also be cited. A reaction terminator may be used to obtain the reaction product and the chain extension reaction product. That is, the urethane resin contains a polyisocyanate compound unit and a polyol compound unit. The urethane resin may contain a chain extender unit and / or a reaction terminator unit.

[0014] Examples of the polyvalent isocyanate compound include polyvalent isocyanate compounds such as aliphatic, alicyclic, and aromatic polyvalent isocyanate compounds. Specific examples of the polyvalent isocyanate 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, 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-isocyanate methyl-3,5,5-trimethylcyclohexyl isocyanate (isophorone diisocyanate), 4,4'-methylenebis(cyclohexyl isocyanate), methyl-2,4-cyclohexane diisocyanate, methyl-2,6-cyclohexane diisocyanate, 1,4-bis(isocyanate methyl)cyclohexane, 1,3-bis(isocyanate methyl)cyclohexane and other alicyclic diisocyanates; 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, dianisidine diisocyanate, 4,4'-diphenyl ether diisocyanate and other aromatic diisocyanates; polyvalent isocyanate compounds which are adducts, isocyanurate compounds, and biuret compounds of the above diisocyanates; triisocyanates such as 1,3,5-triisocyanate benzene, 2,4,6-triisocyanate toluene, 1,3,5-triisocyanate hexane; polyisocyanates such as 4,4'-diphenyl dimethylmethane-2,2'-5,5'-tetraisocyanate. These polyvalent isocyanate compounds may be used alone or in combination of two or more.

[0015] Examples of the polyol compound include polyether polyols obtained by polymerizing oxirane compounds such as ethylene oxide, propylene oxide, butylene oxide, and tetrahydrofuran using low molecular weight polyols such as ethylene glycol, propylene glycol, trimethylolpropane, and glycerin as initiators; 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, and 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, suberic acid, or acid anhydrides or dimer acids corresponding thereto, and polyester polyols obtained by dehydration condensation thereof; polylactone polyols obtained by ring-opening polymerization of lactone monomers (such as γ-butyrolactone, γ-valerolactone, ε-caprolactone, and mixtures of two or more thereof) using the glycols as initiators; polyolefin polyols such as polyethylene polyol and polypropylene polyol; polyether ester polyols obtained by reacting the dibasic acid or their dialkyl esters with the polyether polyol; and polycarbonate polyols obtained by reacting the 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 extender may be used alone or in combination of two or more.

[0017] Examples of the polyamine include diamines having 2 to 12 carbon atoms such as ethylenediamine, propylenediamine, hexamethylenediamine, isophoronediamine, toluenediamine, piperazine, and aminoethylethanolamine; polyalkylene polyamines 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 its derivatives (dibasic acid dihydrazide such as adipic acid dihydrazide). Among them, alicyclic diamines are preferable, and isophoronediamine and aminoethylethanolamine are more preferable, from the viewpoints of the cuttability and substrate adhesiveness of the obtained printing layer and the ink stability of the gravure ink composition. The polyamine may be used alone or in combination of two or more.

[0018] Examples of the polyol include aliphatic diols having 2 to 8 carbon atoms; alicyclic group-containing diols having 6 to 10 carbon atoms such as 1,4-bis(hydroxymethyl)cyclohexane and 2,2-bis(4-hydroxycyclohexyl)propane; aromatic ring-containing diols having 8 to 20 carbon atoms such as m- or p-xylylene glycol, bis(hydroxyethyl)benzene, and bis(hydroxyethoxy)benzene; bisphenols such as bisphenol A, bisphenol S, and bisphenol F; alkylene oxide (hereinafter abbreviated as "AO") adducts thereof, AO adducts of dihydroxynaphthalene, and bis(2-hydroxyethyl) terephthalate. Examples of the aliphatic diol having 2 to 8 carbon atoms include straight-chain diols having a hydroxyl group only at the terminal of the straight-chain structure, such as ethylene glycol, diethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, and 1,6-hexanediol; straight-chain diols having a hydroxyl group other than at the terminal of the straight-chain structure, such as 1,2-propanediol, 1,3-propanediol, and 2,3-propanediol; and diols having a branched alkyl chain, such as neopentyl glycol, 3-methyl-1,5-pentanediol, and 2,2-diethyl-1,3-propanediol. Among them, from the viewpoints of the cuttability of the obtained printing layer and the ink stability of the gravure ink composition, aliphatic diols having 2 to 8 carbon atoms are preferable, and 1,3-propanediol and 1,4-butanediol are more preferable. The polyol may be used alone or in combination of two or more.

[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 the monoamines having 2 to 8 carbon atoms include mono- or dialkylamines 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. The reaction terminator may be used alone or in combination of two or more.

[0020] (Biomass urethane resin) In one aspect of the present invention, the urethane resin is preferably a biomass urethane resin. The biomass urethane resin means a urethane resin in which at least a part of the units constituting the urethane resin is a compound unit derived from biomass. Among them, 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 using a biomass urethane resin, the biomass concentration in the resulting gravure ink composition can be improved. From the perspective of carbon neutrality, the gravure ink composition is an excellent material. Conventionally, although attempts have been made to improve the biomass concentration in the gravure ink composition, the performance has not been sufficient. The inventors of the present application have found that by using a bifunctional polyisocyanate as a curing agent, the overall performance is improved compared to conventional petrochemical-derived urethane resins. In particular, it has been 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, the cuttability and laminate strength of the resulting printed layer can be compatible. Also, when the weight average molecular weight (Mw) is less than 20,000, the blocking resistance is poor. When the weight average molecular weight (Mw) exceeds 90,000, the compatibility is poor. The Mw of the urethane resin is the weight average molecular weight in terms of standard polystyrene molecular weight and is measured by gel permeation chromatography (GPC).

[0023] The urethane resin may contain only a hydroxyl group, only an amino group, or both a hydroxyl group and an amino group as a group capable of reacting with an isocyanate group.

[0024] In one embodiment of the present invention, the urethane resin preferably contains at least a hydroxyl group in the side chain. The introduction of a hydroxyl group into the side chain can be produced, for example, by using a polyamine having a hydroxyl group (such as aminoethyl ethanolamine) as the polyamine of the chain extender described above and performing a chain extension reaction only with 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 viewpoints of cuttability and ink stability. When the hydroxyl value is less than 10 mgKOH / g, the printability and the cuttability of the resulting printed layer are poor. When the hydroxyl value exceeds 45 mgKOH / g, the ink stability is poor. When the hydroxyl value is equal to or higher than the lower limit value of the above range, the printability, the cuttability of the resulting printed layer, and the substrate adhesion are improved. When the hydroxyl value is equal to or lower than the upper limit value of the above range, the printability, the ink stability of the gravure ink composition, and the cuttability 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 use of the polyamine having the above-mentioned hydroxyl group and the like.

[0025] When the urethane resin contains an amino group, the amine value is preferably from 0.1 to 20 mgKOH / g, more preferably from 0.1 to 5 mgKOH / g, and even more preferably from 0.2 to 2 mgKOH / g from the viewpoints of substrate adhesion and ink stability. When the amine value is not less than the lower limit value of the above range, the substrate adhesion of the resulting printed layer is improved. When the amine value is not more than the upper limit value of the above range, the ink stability of the gravure ink composition is improved. The amine value of the urethane resin refers to the value converted to the equivalent of potassium hydroxide after measurement by the potentiometric titration method (for example, COMTITE (AUTOTITRATOR COM-900, BURETB-900, TITSTATION K-900), manufactured by Hiranuma Sangyo Co., Ltd.).

[0026] <Bifunctional polyisocyanate> A bifunctional polyisocyanate is a compound having two isocyanate groups in one molecule. The bifunctional polyisocyanate functions as a curing agent. Examples of the bifunctional polyisocyanate include reaction products of diisocyanate compounds and diol compounds, diisocyanate dimers, and allophanate-modified products. These modified products of diisocyanates are preferred from the viewpoints of cuttability, storage stability, residual solvents, and toxicity. Also, within the range where the physical properties are not affected, the combined use of isocyanates other than the bifunctional polyisocyanate and the use of commercially available products (functional group numbers less than 3) containing a certain amount of non-bifunctional by-products can also be used.

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

[0028] Examples of the diol compound include saturated or unsaturated diol compounds such as 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, 1,5-pentanediol, 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. The diol compound may be used alone or in combination of two or more.

[0029] (Physical properties of bifunctional polyisocyanate) The content of the isocyanate group relative to the total mass of the bifunctional polyisocyanate is 15.0 to 35.0% by mass, preferably 15.0 to 30.0% by mass, and more preferably 15.0 to 25.0% by mass from the viewpoints of ink stability and cuttability. When the isocyanate group content is within the above range, it becomes possible to achieve both the aging stability and cuttability of the ink. When the isocyanate group content is less than 15.0% by mass, the cuttability is poor, and when it exceeds 35.0% by mass, the ink stability decreases.

[0030] The content of isocyanate groups, that is, the NCO content rate (% by mass), can be determined by back-titration with 1N hydrochloric acid after neutralizing the isocyanate groups in the measurement sample with an excess of 2N amine. 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 after removing the volatile components. In this specification, "solid content" means the residue after heating and drying a measurement target (for example, 1 g) at 130 °C for 45 minutes using a circulating air dryer.

[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 viewpoints of stability and compatibility. The viscosity of the bifunctional polyisocyanate at 25 °C can be measured using a B-type viscometer.

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

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

[0034] <Other components> The composition for gravure ink of this embodiment may contain other components in addition to the urethane resin, bifunctional polyisocyanate, and organic solvent. Examples of other components include other resins other than the urethane resin, other polyisocyanates other than the bifunctional polyisocyanate (that is, polyisocyanates having three or more functional groups, curing agents), pigments, and additives.

[0035] Examples of the other resins include vinyl chloride-vinyl acetate copolymer, chlorinated polypropylene, cellulose-based resins, ethylene-vinyl acetate copolymer, vinyl acetate resin, polyamide, acrylic resin, polyester resin, alkyd resin, polyvinyl chloride, rosin-based resins, rosin-modified maleic acid resins, terpene resins, phenol-modified terpene resins, ketone resins, cyclized rubber, chlorinated rubber, butyral, petroleum resins, and modified resins thereof. By further using these resins, the blocking resistance of the obtained printed layer can be improved. These resins may be used alone or in combination of two or more. When the composition for gravure ink of this embodiment contains other resins, among them, by containing vinyl chloride-vinyl acetate copolymer, cellulose-based resin, acrylic resin, or polyester resin, the surface of the obtained printed layer (5 cm × 5 cm in size) and the surface of the base film are overlapped so as to be in contact with each other, and on the laminated piece, 7 kg / cm of weight 2When a load was applied and the laminated sheet was peeled after being stored for 24 hours under the conditions of 40 °C and 80% relative humidity, it was found that the printed layer did not peel off and there was no peel resistance.

[0036] Examples of the other polyisocyanate include polyisocyanates having three or more functional groups. By further using other polyisocyanates, the cuttability and substrate adhesion of the obtained printed layer, and the ink stability of the gravure ink composition can be improved. The other polyisocyanates may be used alone or in combination of two or more. When the gravure ink composition of the present embodiment contains other polyisocyanates, it is preferable to contain a trifunctional polyisocyanate.

[0037] Examples of the additive include a dispersant, a leveling agent, an antifoaming agent, a wax, an antiblocking agent, a plasticizer, a light stabilizer, an infrared absorber, an ultraviolet absorber, a fragrance, a flame retardant, and the like.

[0038] (Vinyl chloride-vinyl acetate copolymer) The 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. Further, the vinyl chloride-vinyl acetate copolymer may contain monomer units (other monomers) other than vinyl chloride units and vinyl acetate units as necessary. The other monomers are not particularly limited as long as they can copolymerize with vinyl chloride and vinyl acetate.

[0039] The vinyl chloride-vinyl acetate copolymer may have a group reactive with an isocyanate group. As the group reactive with an isocyanate group, a hydroxyl group is preferable. The vinyl chloride-vinyl acetate copolymer having a hydroxyl group can be obtained, for example, by saponifying a part of the acetate ester moiety.

[0040] When the vinyl chloride-vinyl acetate copolymer contains a hydroxyl group, the hydroxyl value is preferably 50 to 250 mgKOH / g, more preferably 60 to 200 mgKOH / g, and even more preferably 80 to 180 mgKOH / g from the viewpoints of substrate adhesion and ink stability. When the hydroxyl value is at least the lower limit of the above range, the substrate adhesion is improved. 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 the vinyl chloride unit relative to the total mass of the vinyl chloride-vinyl acetate copolymer is preferably 80 to 95% by mass, more preferably 88 to 93% by mass. When the content of the vinyl chloride unit is within the above range, the substrate adhesion of the resulting printed layer is improved.

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

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

[0044] The cellulosic resin, acrylic resin, and polyester resin may have a group reactive with an isocyanate group. As the group reactive with an isocyanate group, a hydroxyl group is preferred.

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

[0046] (Trifunctional polyisocyanate) The trifunctional polyisocyanate is a compound having three isocyanate groups in one molecule. The trifunctional polyisocyanate functions as a curing agent. As the trifunctional polyisocyanate, known trifunctional polyisocyanates in the art can be used, such as compounds having three isocyanate groups exemplified by the above polyvalent isocyanate compounds, adducts of the bifunctional polyisocyanates, isocyanurate bodies, biuret bodies, etc. can be cited as examples.

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

[0048] (Pigment) Examples of the pigment include inorganic pigments, organic pigments, extender pigments, etc. Examples of inorganic pigments include titanium oxide, zinc oxide, zinc sulfide, barium sulfate, silica, aluminum, calcium carbonate, chromium oxide, red iron oxide, mica, etc. The inorganic pigment may be used alone or in combination of two or more. In particular, it is desirable to use titanium oxide from the viewpoint of hiding power. As the titanium oxide pigment, a titanium oxide pigment having a rutile crystal structure is preferred. Further, the surface of the titanium oxide pigment is preferably surface-treated with silica and / or alumina. By having a treatment layer of silica and / or alumina, the printing suitability of the gravure ink is improved. Further, the titanium oxide pigment may be treated with other metals or oxides, and examples thereof include simple metals of Si, Al, Zn, or Zr, oxides of Al, Zn, etc. The above-mentioned "treated" 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 amount of 14 to 40 mL / 100 g, more preferably 17 to 30 mL / 100 g, as measured by the measurement method defined in JIS K5101. Further, the average particle diameter (median particle diameter) measured by a transmission electron microscope is preferably 0.15 μm to 0.35 μm, 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, mica. The extender pigment may be used alone or in combination of two or more. Examples of silica include sodium silicate, silicon tetrachloride, calcium silicate, aluminum silicate, etc. From the viewpoints of improving blocking resistance, printing suitability, and residual solvent, it is preferable to contain silica. As the silica, surface-treated silica is more preferable.

[0050] Examples of the organic pigments include those commonly used in the gravure ink composition. For example, 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, ansanthrone pigments, indanthrone pigments, flavanthrone pigments, pyranthrone pigments, diketopyrrolopyrrole pigments, and the like can be mentioned. These pigments can be used alone or in combination of two or more.

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

[0052] <Medium, Gravure Ink> A composition obtained by adding the gravure ink composition of the present embodiment and silica is referred to as a medium. A composition obtained by adding the gravure ink composition of the present embodiment and a pigment is referred to as a gravure ink. That is, the gravure ink composition of the present invention can be suitably used as a gravure ink or a medium for color adjustment. However, in the use of the medium, it is not limited to color adjustment, and it is also one of the preferred forms to be used as a varnish. For example, in a laminate having a printed layer formed from the above gravure ink, the cuttability of the printed layer is excellent. Further, the medium has excellent printability of the gravure ink after color adjustment, and in a laminate having a printed layer formed from the gravure ink or varnish, the blocking resistance, residual solvent, and cuttability of the printed layer are excellent.

[0053] <Composition of Gravure Ink Composition (Medium, Gravure Ink)> The content of the solid component of the urethane resin with respect to the total mass of the gravure ink composition is preferably 4 to 15% by mass, more preferably 5 to 13% by mass, and even more preferably 6 to 11% by mass. When the content of the urethane resin is within the above range, the adhesion of the obtained printed layer to the substrate and the ink stability of the gravure ink composition are improved. The content of the solid component of the urethane resin with respect to the total mass of the solid component of the gravure ink composition is 10 to 65% by mass, preferably 10 to 55% by mass, more preferably 13 to 50% by mass, and even more preferably 15 to 45% by mass. When the content of the urethane resin is within the above range, the adhesion of the obtained printed layer to the substrate and the ink stability of the gravure ink composition are improved. When the content of the solid component of the urethane resin with respect to the total mass of the solid component of the gravure ink composition is less than 10% by mass, the adhesion to the substrate is poor. On the other hand, when the content of the solid component exceeds 65% by mass, the blocking resistance and ink stability are poor.

[0054] The content of the solid component of the bifunctional polyisocyanate with respect to the total mass of the gravure ink composition is preferably 0.6 to 2.7% by mass, more preferably 0.7 to 2.6% by mass, and even more preferably 0.8 to 2.5% by mass. When the content of the bifunctional polyisocyanate is within the above range, the cuttability and substrate adhesion of the obtained printed layer, and the ink stability of the gravure ink composition are improved. The content of the solid component of the bifunctional polyisocyanate with respect to the total mass of the solid component of the gravure ink composition is preferably 1.5 to 13.5% by mass, more preferably 1.5 to 11.5% by mass, and even more preferably 1.5 to 11.0% by mass. When the content of the bifunctional polyisocyanate is within the above range, the cuttability and substrate adhesion of the obtained printed layer, and the ink stability of the gravure ink composition are improved.

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

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

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

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

[0059] When the composition for gravure ink contains a vinyl chloride-vinyl acetate copolymer, the content of the solid component of the vinyl chloride-vinyl acetate copolymer relative to the total mass of the composition for gravure ink is preferably 1.0 to 6.0% by mass, more preferably 1.3 to 5.5% by mass, and even more preferably 1.5 to 5.0% by 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 an appropriate ink viscosity is achieved. When the composition for gravure ink contains a vinyl chloride-vinyl acetate copolymer, the content of the solid component of the vinyl chloride-vinyl acetate copolymer relative to the total mass of the solid components of the composition for gravure ink is preferably 3 to 30% by mass, more preferably 4 to 25% by mass, and even more preferably 4 to 20% by 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 residual solvent is reduced.

[0060] When the composition for gravure ink contains a cellulose-based resin, the content of the solid component of the cellulose-based resin relative to the total mass of the composition for gravure ink is preferably 0.1 to 10% by mass, and more preferably 0.3 to 5% by mass from the viewpoint of improving substrate adhesion and blocking resistance. When the composition for gravure ink contains a cellulose-based resin, the content of the solid component of the cellulose-based resin relative to the total mass of the solid components of the composition for gravure ink is preferably 0.3 to 15% by mass, more preferably 0.5 to 10% by mass, and even more preferably 0.5 to 5% by mass. When the content of the solid component of the cellulose-based resin with respect to the total mass of the solid component of the gravure ink composition is less than 0.3% by mass, the peeling area in the substrate adhesion test in the examples described later is 10 to 12%, and in the blocking resistance test in the examples described later, less than 10% of the printed layer peeled off and the peeling resistance was slight. When the content of the solid component of the cellulose-based resin with respect to the total mass of the solid component of the gravure ink composition is 0.3% by mass or more and less than 0.5% by mass, the peeling area in the substrate adhesion test is 12 to 15%, and in the blocking resistance test, less than 10% of the printed layer peeled off and the peeling resistance was slight. When the content of the solid component of the cellulose-based resin with respect to the total mass of the solid component of the gravure ink composition is 0.5 to 5% by mass, the peeling area in the substrate adhesion test is 15 to 20%, and in the blocking resistance test, the printed layer did not peel off and there was no peeling resistance. When the content of the solid component of the cellulose-based resin with respect to the total mass of the solid component of the gravure ink composition is 5 to 10% by mass, the peeling area in the substrate adhesion test is 20 to 25%, and in the blocking resistance test, the printed layer did not peel off and there was no peeling resistance. When the content of the solid component of the cellulose-based resin with respect to the total mass of the solid component of the gravure ink composition is 10 to 15% by mass, the peeling area in the substrate adhesion test is 20 to 25%, and in the blocking resistance test, less than 10% of the printed layer peeled off and the peeling resistance was slight. When the content of the solid component of the cellulose-based resin with respect to the total mass of the solid component of the gravure ink composition exceeds 15% by mass, the peeling area in the substrate adhesion test is 25 to 30%, and in the blocking resistance test, less than 10% of the printed layer peeled off and the peeling resistance was slight. Also, regardless of which range these contents are in, it was a preferable range as the evaluation result in the present invention.

[0061] When the gravure ink composition contains a polyester resin, the content of the solid component of the polyester resin with respect to the total mass of the gravure ink composition is preferably 0.1 to 10% by mass, and more preferably 0.3 to 5% by mass from the viewpoints of improving substrate adhesion and blocking resistance. When the composition for gravure ink contains a polyester resin, the content of the solid component of the polyester resin with respect to the total mass of the solid components of the composition for gravure ink is preferably 0.3 to 15% by mass, more preferably 0.5 to 10% by mass, still more preferably 0.5 to 5% by mass, and particularly preferably 0.5 to 3% by mass from the viewpoints of improving substrate adhesion and blocking resistance.

[0062] When the composition for gravure ink contains an acrylic resin, the content of the solid component of the acrylic resin with respect to the total mass of the composition for gravure ink is preferably 0.1 to 10% by mass, and more preferably 0.3 to 5% by mass from the viewpoints of improving substrate adhesion and blocking resistance. When the composition for gravure ink contains an acrylic resin, the content of the solid component of the acrylic resin with respect to the total mass of the solid components of the composition for gravure ink is preferably 0.3 to 15% by mass, more preferably 0.5 to 10% by mass, still more preferably 0.5 to 5% by mass, and particularly preferably 0.5 to 3% by mass from the viewpoints of improving substrate adhesion and blocking resistance.

[0063] The content of the solid component of other resins other than vinyl chloride-vinyl acetate copolymer, cellulose-based resin, polyester resin, and acrylic resin with respect to the total mass of the composition for gravure ink is preferably 0.5% by mass or less, more preferably 0.1% by mass or less, and particularly preferably not contained. The content of the solid component of other resins other than vinyl chloride-vinyl acetate copolymer, cellulose-based resin, and polyester resin with respect to the total mass of the solid components of the composition for gravure ink is preferably 1% by mass or less, more preferably 0.2% by mass or less, and particularly preferably not contained.

[0064] When the composition for gravure ink contains a polyisocyanate having three or more functional groups, the content of the solid component of the polyisocyanate having three or more functional groups with respect to the total mass of the composition for gravure ink is preferably 0.1 to 2.0% by mass, more preferably 0.1 to 1.8% by mass, still more preferably 0.1 to 1.5% by mass, still more preferably 0.1 to 1.2% by mass, and particularly preferably 0.1 to 0.7% by mass. When the polyisocyanate having three or more functional groups is within the above range, the cuttability of the obtained printed layer and the ink stability of the composition for gravure ink are improved. The content of the solid component of the polyisocyanate having three or more functional groups with respect to the total mass of the solid component of the composition for gravure ink is 0.5 to 10.0% by mass, more preferably 0.5 to 9.0% by mass, still more preferably 0.5 to 8.0% by mass, still more preferably 0.5 to 2.7% by mass, and particularly preferably 0.5 to 1.6% by mass. When the content of the polyisocyanate having three or more functional groups is within the above range, the cuttability of the obtained printed layer and the ink stability of the composition for gravure ink are improved.

[0065] When the composition for gravure ink further contains a trifunctional polyisocyanate, the content of the solid component of the trifunctional polyisocyanate with respect to the total mass of the composition for gravure ink is preferably 0.1 to 2.0% by mass, more preferably 0.1 to 1.8% by mass, still more preferably 0.1 to 1.5% by mass, still more preferably 0.1 to 1.2% by mass, and particularly preferably 0.1 to 0.7% by mass. When the content of the trifunctional polyisocyanate is within the above range, the cuttability of the obtained printed layer and the ink stability of the composition for gravure ink are improved. The content of the solid component of the trifunctional polyisocyanate relative to the total mass of the solid component of the gravure ink composition is preferably 0.5 to 10.0% by mass, more preferably 0.5 to 9.0% by mass, still more preferably 0.5 to 8.0% by mass, still more preferably 0.5 to 2.7% by mass, and particularly preferably 0.5 to 1.6% by mass. When the content of the trifunctional polyisocyanate is within the above range, the cuttability of the obtained printing layer and the ink stability of the gravure ink composition are improved.

[0066] The content of the solid component of the polyisocyanate having four or more functional groups relative to the total mass of the gravure ink composition is preferably 1% by mass or less, more preferably 0.7% by mass or less, and still more preferably 0.3% by mass or less. The content of the solid component of the polyisocyanate having four or more functional groups relative to the total mass of the solid component of the gravure ink composition is preferably 5% by mass or less, more preferably 2% by mass or less, and still more preferably 1% by 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 viewpoints of cuttability and ink stability. When the mass ratio is within the above range, the cuttability of the obtained printing layer and the ink stability of the gravure ink composition are improved. Also, when the ratio of the urethane resin at the mass ratio of 3.0:1.0 is less than 3.0, the effect is inferior from the viewpoints of substrate adhesion and printability. On the other hand, when the ratio of the urethane resin at the mass ratio of 13.0:1.0 exceeds 13.0, the cuttability decreases. Note that the mass ratio is the mass ratio of the solid components after removing the volatile components when the urethane resin and the bifunctional polyisocyanate contain an organic solvent (when the product contains an organic solvent).

[0068] When the composition for gravure ink contains the above-mentioned other resin, the mass ratio of the urethane resin to the other resin (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 even more preferably 1.0:0.2 to 1.0:0.6 from the viewpoints of blocking resistance and substrate adhesion. When the composition for gravure ink 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 even more preferably 1.0:0.2 to 1.0:0.6 from the viewpoints of blocking resistance and residual solvent. When the mass ratio is within the above range, the ink stability and substrate adhesion are improved. When the composition for gravure ink contains the above-mentioned other resin, the mass ratio of the total of the urethane resin and the other resin to the polyisocyanate (including both bifunctional and trifunctional or higher) (urethane resin + other resin: 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 composition for gravure ink 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) (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 the mass ratio is within the above range, the cuttability and substrate adhesion of the obtained printed layer, and the ink stability of the composition for gravure ink are improved. In addition, when the urethane resin, polyisocyanate, and vinyl chloride-vinyl acetate copolymer contain an organic solvent (when the product contains an organic solvent), the mass ratio is the mass ratio of the solid components after removing the volatile components.

[0069] When the composition for gravure ink contains a polyisocyanate having three or more functional groups, the mass ratio of the bifunctional polyisocyanate to the polyisocyanate having three or more functional groups (bifunctional polyisocyanate: polyisocyanate having three or more functional groups) is preferably 1.0:0.1 to 1.0:2.0, more preferably 1.0:0.1 to 1.0:1.6, still 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. When the amount of the polyisocyanate having three or more functional groups increases, the cuttability deteriorates and the amount of the residual solvent also increases. When the composition does not contain a polyisocyanate having four or more functional groups, the above-mentioned bifunctional polyisocyanate: polyisocyanate having three or more functional groups is read as bifunctional polyisocyanate: trifunctional polyisocyanate. When the composition for gravure ink contains a polyisocyanate having three or more functional groups, the mass ratio of the urethane resin to the total of the bifunctional polyisocyanate and the polyisocyanate having three or more functional groups (urethane resin: bifunctional polyisocyanate + polyisocyanate having three or more functional groups) is preferably 13.0:1.0 to 3.0:1.0, more preferably 12.0:1.0 to 3.0:1.0, and even more preferably 11.0:1.0 to 3.0:1.0 from the viewpoints of cuttability, ink stability, and blocking resistance. When the composition does not contain a polyisocyanate having four or more functional groups, the urethane resin: bifunctional polyisocyanate + polyisocyanate having three or more functional groups is read as urethane resin: bifunctional polyisocyanate + trifunctional polyisocyanate. When the mass ratio is within the above range, the cuttability and the residual solvent become good. In addition, when the bifunctional polyisocyanate and the polyisocyanate having three or more functional groups to be measured contain an organic solvent (when the product contains an organic solvent), the mass ratio is the mass ratio of the solid components obtained by removing the volatile components.

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

[0071] ≪Laminate≫ The laminate of this embodiment has a printing layer formed from the medium or gravure ink of this embodiment. Hereinafter, with reference to FIG. 1, the laminate of this embodiment will be described. 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 base material 11, a printing layer 12, and a second base material 14. The printing layer 12 is formed on one surface (upper surface) 11a of the first base material 11. An adhesive layer 13 is formed on the surface (upper surface) 12a of the printing layer 12 opposite to the surface in contact with the first base material 11. The second base material 14 is provided on the surface (upper surface) 13a of the adhesive layer 13 opposite to the surface in contact with the printing layer 12. That is, in the laminate 10, the first base material 11, the printing layer 12, the adhesive layer 13, and the second base material 14 are 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) films; polycarbonate films; polyimide films; polyvinyl chloride films; and the like. Either stretched or unstretched plastic films such as biaxially stretched PP films and unstretched PP films can be used. Further, substrates provided with a metal vapor deposition layer such as aluminum vapor deposition or substrates provided with a transparent vapor deposition layer such as alumina and silica can also be used. Furthermore, 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 using colored ink may be applied to the surface of the substrate.

[0074] Examples of the second substrate 14 include films such as polyethylene, polypropylene, and other polyolefin substrates, or film-like sealants made of composite materials thereof. Examples of the method for laminating the resin layer include known lamination methods such as the dry lamination method in which another plastic film (resin layer) is laminated on a printing layer provided on a plastic film via an adhesive layer, and the extrusion lamination method in which a molten resin is laminated via an anchor coat agent layer as required. The thickness of the resin layer is preferably, for example, 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. As the adhesive, a two-component adhesive composed of a mixture of a polyol and an isocyanate curing agent is preferably used. Examples of the polyol include polyester-based and polyether-based polyols. Specifically, TM-250HV / CAT-RT86L-60, TM-550 / CAT-RT37, TM-314 / CAT-14B, etc. manufactured by Toyo Morton Co., Ltd. can be mentioned.

[0076] <Method for manufacturing a laminate> The laminate of the present embodiment is obtained by printing medium or gravure ink on the upper surface 11a of the first substrate 11 to form a printing layer 12, forming an adhesive layer 13 on the upper surface 12a of the printing layer 12, and bonding (laminating) the first substrate 11 and the second substrate 14 through the adhesive layer 13. As the laminating process, for example, a dry lamination method or the like is used. The dry lamination method is a method of applying and drying an adhesive on a printing layer of a printed matter or a sealant, and laminating by pressure-bonding the printed matter and the sealant.

[0077] According to the laminate 10 of the present embodiment, by having a printing layer 12 formed of a medium or gravure ink containing the composition for gravure ink of the present embodiment as the medium or gravure ink, the cuttability of the printing layer is excellent compared to the case of using a conventional medium or gravure ink.

[0078] <Use> The laminate 10 is preferably used as a packaging material. As the packaging material, a packaging material for flexible packaging is preferred. "Flexible packaging" refers to a packaging material composed of a flexible material, that is, a flexible package, and is used for packaging foods, daily necessities, etc.

[0079] <Mechanism of action> The composition for gravure ink of the present invention contains a bifunctional polyisocyanate. Compared with a trifunctional polyisocyanate, in the case of a bifunctional polyisocyanate, there are fewer crosslinking points that can crosslink with the polyurethane resin. Therefore, compared with the case of a trifunctional polyisocyanate, three-dimensional crosslinking hardly proceeds, and it is considered that a crosslinked body (printing layer) having a relatively sparse structure is formed. As a result, it is considered that the above-described adhesive easily penetrates into the printing layer and the cuttability is improved. In addition, as shown in the above-described examples, depending on the type of trifunctional polyisocyanate, the cuttability may be improved. However, in this case, there may arise a problem that the amount of residual solvent increases.

Examples

[0080] Hereinafter, the present invention will be described more specifically with reference to Examples and Comparative Examples, but the present invention is not limited to the following Examples.

[0081] <Evaluation method> (Cuttability) Regarding the laminates of Examples and Comparative Examples, the cuttability was evaluated by a sensory test in which a cut was made with a cutter in a direction perpendicular to the printing at the edge of the printed portion and the laminate was torn by hand. The evaluation criteria were as follows, and A to C were considered acceptable. A: It cuts without resistance. B: There is a slight resistance, but it cuts. C: There is a resistance, but it cuts. D: The resistance is strong and it cuts while stretching. E: The LLDPE stretches and it cannot be cut.

[0082] (Ink stability) The viscosity (V1) of the gravure ink composition immediately after mixing the binder resin compositions and the curing agent compositions of the examples and comparative examples, and the viscosity (V2) of the gravure ink composition after storage at 20°C for 24 hours were measured using a Zahn cup #3 manufactured by Reika Co., Ltd., and the viscosity increase (viscosity (V2) - viscosity (V1)) was calculated. The measurement temperature of the viscosity was 20°C. The ink stability was evaluated according to the following evaluation criteria. The ink stability is an index of the fluidity of the gravure ink composition, and the shorter the viscosity increase, that is, the better the ink stability, the better the fluidity. The evaluation criteria were as follows, and A to C were considered passing. A: The viscosity increase is less than 1 second. B: The viscosity increase is 1 second or more and less than 3 seconds. C: The viscosity increase is 3 seconds or more and less than 5 seconds. D: The viscosity increase is 5 seconds or more and less than 10 seconds. E: The viscosity increase is 10 seconds or more.

[0083] (Substrate adhesion) A cellophane adhesive tape (manufactured by Nichiban Co., Ltd., width 18 mm) was attached 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 substrate adhesion of the printed layer was evaluated according to the following criteria. The evaluation criteria were as follows, and A to C were considered passing. A: The peeled area is less than 10%. B: The peeled area is 10% or more and less than 30%. C: The peeled area is 30% or more and less than 50%. D: The peeled area is 50% or more and less than 90%. E: The peeled area is 90% or more.

[0084] (Printing suitability) Using a gradation plate, the gravure ink compositions of the examples and comparative examples were printed on a PET film (manufactured by Toyobo Co., Ltd.) with a thickness of 25 μm at a speed of 100 m / min. The printed matter was visually observed to confirm the presence of highlights and evaluate streaks. The evaluation criteria were as follows, and A to B were considered passing. A: No streaks were observed at all. B: Mold release was observed in cells with 5% or more and less than 10%. C: Mold release was observed in cells with 10% or more and less than 20%. D: Mold release was observed in cells with 20% or more.

[0085] (Residual solvent) The gravure ink compositions of the examples and comparative examples were printed on a PET film (manufactured by Toyobo Co., Ltd.) with a thickness of 12 μm. The obtained printed layer was cut into a size of 10 cm in width and 15 cm in length. Three pieces were put into an Erlenmeyer flask, sealed, and heated. (Temperature: 80 °C, 30 minutes) Then, 1.0 ml of the air in the flask was extracted and analyzed by gas chromatography (GC) to confirm the amount of solvent components. The evaluation criteria were as follows, and A to C were considered qualified. A: The total amount of residual solvent was less than 2 mg / m 2 . B: The total amount of residual solvent was 2 mg / m 2 or more and less than 4 mg / m 2 . C: The total amount of residual solvent was 4 mg / m 2 or more and less than 6 mg / m 2 . D: The total amount of residual solvent was 6 mg / m 2 or more and less than 8 mg / m 2 . E: The total amount of residual solvent was 8 mg / m 2 or more.

[0086] (Blocking resistance) The printed materials of the examples and comparative examples were cut to prepare test pieces with a size of 5 cm × 5 cm. The prepared test pieces were overlapped so that the surface of the printed layer and the surface of the base film were in contact to obtain a laminated test piece. A load of 7 kg / cm 2 was applied and stored under the conditions of 40 °C and 80% relative humidity for 24 hours. The state of the printed layer when the laminated test piece was peeled off was observed, and the peel resistance was confirmed. The blocking resistance was evaluated according to the evaluation criteria shown below. The evaluation criteria were as follows, and A to C were considered qualified. A: The printing layer did not peel off and there was no peeling resistance. B: Less than 10% of the printing layer peeled off and there was a slight peeling resistance. C: 10% or more and less than 30% of the printing layer peeled off and there was a peeling resistance. D: 30% or more and less than 50% of the printing layer peeled off and there was a strong peeling resistance. E: 50% or more of the printing layer peeled off and there was a considerably strong peeling resistance.

[0087] <Raw materials used> As the urethane resin (A) and other resins (a), the following compounds were used. · A1: Urethane resin (Mw = 69000, hydroxyl value = 12 mg KOH / g). · A2: Urethane resin (Mw = 42000, hydroxyl value = 34 mg KOH / g). · A3: Urethane resin (Mw = 71000, hydroxyl value = 5 mg KOH / g). · A4: Urethane resin (Mw = 37000, hydroxyl value = 55 mg KOH / g). · a1: Vinyl chloride - vinyl acetate copolymer (trade name "Solvaine TA5R", Mw = 61000, hydroxyl value = 170 mg KOH / g (manufactured by Nissin Chemical Industry Co., Ltd.). · a2: Cellulose - based resin (nitrocellulose, hydroxyl value = about 142 mg KOH / g). · a3: Cellulose - based resin (cellulose acetate butyrate, hydroxyl value = about 43 mg KOH / g). · a4: Cellulose - based resin (cellulose acetate propionate, hydroxyl value = about 86 mg KOH / g). · a5: Polyester resin (hydroxyl value = about 39 mg KOH / g). · a6: Acrylic resin (hydroxyl value = about 22 mg KOH / g).

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

[0089] As the pigment (C), the following compounds were used. ·C1: Titanium oxide: trade name "Titax JR-806" (manufactured by Teika Corporation). ·C2: Copper phthalocyanine blue: (manufactured by Dainichi Seika Kogyo Co., Ltd., C.I. Name "PB-15:3").

[0090] As the organic solvent (D), the following compounds were 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 - 27, Comparative Examples 1 - 16] (Preparation of Gravure Ink) The urethane resin (A), other resin (a), pigment (C), and organic solvent (D) were mixed and then dispersed in a bead mill to prepare a binder resin composition. Also, the bifunctional polyisocyanate (B), trifunctional polyisocyanate (b), and ethyl acetate were mixed to prepare a curing agent composition. The binder resin composition and the curing agent composition were mixed to prepare a composition for gravure ink. The amounts of the urethane resin (A), other resin (a), pigment (C), organic solvent (D), bifunctional polyisocyanate (B), and trifunctional polyisocyanate (b) were made to be the amounts shown in Tables 1 - 3. The amounts of the urethane resin (A), other resin (a), pigment (C), bifunctional polyisocyanate (B), and trifunctional polyisocyanate (b) mean the solid content. The amount of the organic solvent (D1) means the total amount of the organic solvent added during the preparation of the binder resin composition and the curing agent composition, and the amount of the organic solvent (D2) means the total amount of the volatile components (organic solvents) contained in the products of the above-mentioned urethane resin (A), bifunctional polyisocyanate (B), and trifunctional polyisocyanate (b). Note that the numerical values of the gravure ink compositions in Tables 1 to 3 represent parts by mass, and blanks mean 0. Also, (A) / (B) in Tables 1 to 3 represents the mass ratio of the solid content of the urethane resin to the solid content of the bifunctional polyisocyanate. Further, in the solid content, (A) represents the content of the solid content of the urethane resin with respect to the total mass of the solid content of the gravure ink composition, (a) represents the content of the solid content of other resins with respect 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 with respect to the total mass of the solid content of the gravure ink composition.

[0092] (Preparation of laminate) As the base film, a corona discharge-treated PET film (trade name "Ester E5102", manufactured by Toyobo Co., Ltd., thickness 12 μm) was prepared. Using a gravure plate of Helio 175 lines, a gravure ink composition was applied to the treated surface side of the base film by the gravure printing method to form a printed layer, and a printed matter was obtained. To the obtained printed matter, an adhesive for dry lamination ("Seikabond E-593 / C-77" manufactured by Dainichi Seika) was applied and dried by the gravure printing method so that the dry coating amount was 3 g / m 2 and then heat-pressed with LLDPE (manufactured by Futamura Chemical Co., Ltd., trade name "LLXMTN"), and then 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 cuttability and satisfied the physical properties required for other gravure ink compositions. The laminates formed from the gravure ink compositions of Comparative Examples 2 to 5, 7, 8, 10 to 13, and 15 had low cuttability. The laminate formed from the gravure ink composition of Comparative Example 1 had high cuttability, but had a large amount of organic solvent remaining in the printed layer and did not satisfy the physical properties required for the gravure ink composition. The laminate formed from the gravure ink composition of Comparative Example 6 had high cuttability, but had low ink stability of the gravure ink composition, poor printing suitability, a large amount of organic solvent remaining in the printed layer, and did not satisfy the physical properties required for the gravure ink composition. The laminate formed from the gravure ink composition of Comparative Example 9 had high cuttability, but had low substrate adhesion of the printed layer, poor printing suitability, and did not satisfy the physical properties required for the gravure ink composition. The laminates formed from the gravure ink compositions of Comparative Examples 14 and 16 had high cuttability, but had low ink stability of the gravure ink composition and did not satisfy the physical properties required for the gravure ink composition. Also, when comparing Example 1 and Example 2 where only the urethane resin was different, the cuttability evaluation was the same for Example 1 and Example 2 (slightly resistant but cuttable), but among them, Example 2 with a higher hydroxyl value had higher cuttability. In Examples 11 to 13 where a trifunctional polyisocyanate was further added to Example 5, as the addition amount of the trifunctional polyisocyanate increased (Example 11 → 13), the amount of organic solvent remaining in the printed layer increased. When comparing Example 2 and Example 14 where only the presence or absence of the other resin (a) was different, Example 2 containing the other resin (a) was superior in the evaluation of ink stability, substrate adhesion, printing suitability, and residual solvent. Also, in Examples 15 to 18 containing a cellulose-based resin, the evaluation of substrate adhesion was B in all cases, but in Example 15 where the content of the cellulose-based resin was the highest, the peeled area was slightly larger compared to Examples 16 to 18. On the other hand, in Example 18 where the content of the cellulose-based resin was the lowest, the blocking resistance was slightly inferior compared to Examples 15 to 17.

[0097] [Reference Examples] In Reference Examples 1A to 27A where a gravure ink composition containing no other resin (a) and pigment (C) but containing silica was used in Examples 1 to 27, the same effects as in Examples 1 to 27 were obtained. In Comparative Examples 1 to 16, in Reference Comparative Examples 1A to 16A where a gravure ink composition containing no other resin (a) and pigment (C) but containing silica was used, the evaluation results were inferior to those of Reference Examples 1A to 27A in the same manner as in Comparative Examples 1 to 16. In Reference Examples 1B to 27B where a gravure ink composition containing no other resin (a) but containing a pigment and silica was used in Examples 1 to 27, the same effects as in Examples 1 to 27 were obtained. In Comparative Examples 1 to 16, in Reference Comparative Examples 1B to 16B where a gravure ink composition containing no other resin (a) but containing a pigment and silica was used, the evaluation results were inferior to those of Reference Examples 1B to 27B in the same manner as in Comparative Examples 1 to 16.

Industrial Applicability

[0098] The gravure ink composition of the present invention is useful for improving the cuttability of the obtained laminate and satisfying the physical properties required for the gravure ink composition.

Explanation of Symbols

[0099] 10 Laminate 11 First substrate 12 Printing layer 13 Adhesive layer 14 Second substrate

Claims

1. 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 mass%. (2) The mass ratio of the urethane resin to the difunctional polyisocyanate in terms of solid content is 13.0:1.0 to 3.0:1.

0. (3) The urethane resin has a hydroxyl value of 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 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, 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. (7) In the case where the composition further contains a tri- or higher functional polyisocyanate, the content of the solid content of the tri- or higher functional polyisocyanate relative to the total mass of the solid content of the gravure ink composition is 0.5 to 10 mass %.

2. The gravure ink composition according to claim 1, wherein the other resin contains a vinyl chloride-vinyl acetate copolymer, and a 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 printing 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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