Light-blocking printed matter and laminate

Abstract

To provide a light-shielding printed matter and a laminate in which excellent shielding effect is obtained and the content of residual organic solvent and chlorine is small even if vinyl chloride / vinyl acetate copolymer resin is not used.SOLUTION: A light-shielding printed matter has a substrate layer, a white ink layer formed on the substrate layer, and a gray ink layer formed on the white ink layer, where the white ink layer is a layer including white pigment and binder resin satisfying a predetermined condition 1, the gray ink layer is a layer including white pigment, black pigment and binder resin satisfying a predetermined condition 2, and a ratio (mass%) of the white pigment and the black pigment contained in the gray ink layer is white pigment / black pigment=95 / 5 to 70 / 30.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a light-shielding printed material and a laminate. [Background technology]

[0002] Flexible packaging products, such as packaging bags and containers for storing various products such as food and beverages and detergents, are at risk of their contents changing or deteriorating due to external light. Therefore, aluminum foil, aluminum-deposited film, and other materials are used in packaging products to provide light-blocking properties. However, aluminum foil and other deposited films have poor bending resistance, are prone to pinholes, and generate sparks when heated in a microwave oven. Furthermore, aluminum foil and other deposited films react to metal detectors, hindering the detection of foreign objects (such as metal fragments). Furthermore, aluminum foil is difficult to separate from and incinerated, making it undesirable from an environmental perspective. Therefore, products that use printing to replace aluminum foil and aluminum-deposited film have been proposed.

[0003] Patent Document 1 discloses an opaque printed matter in which a white ink layer containing a polyurethane resin and a vinyl chloride-vinyl acetate copolymer resin as binder resins and a gray ink layer containing a polyurethane resin and a vinyl chloride-vinyl acetate copolymer resin as binder resins are laminated on at least one layer of a base material layer. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 6864774 Summary of the Invention [Problem to be solved by the invention]

[0005] However, the printed matter described in Patent Document 1 uses a vinyl chloride-vinyl acetate copolymer resin, which has the problem of containing a large amount of chlorine and leaving a large amount of residual solvent.

[0006] The present invention was made in consideration of these conventional problems, and aims to provide a light-blocking printed material and laminate that achieves excellent shielding effect without using vinyl chloride-vinyl acetate copolymer resin and has a low content of residual organic solvents and chlorine. [Means for solving the problem]

[0007] The present invention, which solves the above problems, mainly comprises the following configuration.

[0008] (1) A light-blocking printed matter having a base layer, a white ink layer formed on the base layer, and a gray ink layer formed on the white ink layer, wherein the white ink layer is a layer containing a white pigment and a binder resin that satisfies the following condition 1, and the gray ink layer is a layer containing a white pigment, a black pigment, and a binder resin that satisfies the following condition 2, and the ratio (mass %) of the white pigment to the black pigment contained in the gray ink layer is white pigment / black pigment = 95 / 5 to 70 / 30. (Condition 1) The binder resin contained in the white ink layer is a polyurethane resin (A) having a urethane bond and a urea bond each having an amino group at its terminal; and at least one of a polyurethane resin (B) having a urethane bond but not a urea bond and a cellulose acetate propionate (C), The content ratio of the polyurethane resin (A), the polyurethane resin (B) and the cellulose acetate propionate (C) is (A) / ((B)+(C))=95 / 5 to 50 / 50 in terms of solid content mass ratio. (Condition 2) The binder resin contained in the gray ink layer is a polyurethane resin (A) having a urethane bond and a urea bond each having an amino group at its terminal; and at least one of a polyurethane resin (B) having a urethane bond but not a urea bond and a cellulose acetate propionate (C), The content ratio of the polyurethane resin (A), the polyurethane resin (B) and the cellulose acetate propionate (C) is (A) / ((B)+(C))=95 / 5 to 50 / 50 in terms of solid content mass ratio.

[0009] With this configuration, the light-blocking printed matter can achieve excellent shielding effects without using vinyl chloride-vinyl acetate copolymer resin. In addition, the light-blocking printed matter contains little residual organic solvent and chlorine.

[0010] (2) The light-shielding printed matter according to (1), wherein the white ink layer has a thickness of 2 to 10 μm, and the gray ink layer has a thickness of 1 to 5 μm.

[0011] With this configuration, the light-shielding printed matter has a high whiteness, high hiding power, and improved visibility of characters and the like.

[0012] (3) The light-shielding printed matter according to (1) or (2), wherein the urethane group concentration of the polyurethane resin (A) is 0.3 to 2.4 mmol / g, and the urethane group concentration of the polyurethane resin (B) is 2.0 to 6.0 mmol / g.

[0013] With this configuration, the light-shielding printed matter is easy to prepare from polyurethane resin and has excellent adhesion.

[0014] (4) The light-shielding printed matter according to any one of (1) to (3), wherein the polyurethane resin (B) has a mass average molecular weight of 1,000 to 6,000.

[0015] With this configuration, the light-shielding printed matter has excellent adhesion.

[0016] (5) The light-shielding printed matter according to any one of (1) to (4), wherein the polyurethane resin (A) has an amine value of 1.0 to 15.0 mgKOH / g.

[0017] According to this configuration, the ink composition has excellent stability over time, and the light-shielding printed matter has excellent blocking resistance.

[0018] (6) The light-shielding printed matter according to any one of (1) to (5), wherein at least one of the polyurethane resin (A) and the polyurethane resin (B) is a biomass polyurethane resin.

[0019] With this configuration, the light-shielding printed matter can further contribute to preventing global warming and reducing the environmental load.

[0020] (7) The light-shielding printed matter according to any one of (1) to (6), wherein the white ink composition contains at least one of an adhesion improver and an anti-blocking agent.

[0021] With this configuration, the light-shielding printed matter has better adhesion or blocking resistance.

[0022] (8) A light-shielding printed matter as described in (7), wherein the adhesion improver includes at least one of rosin, rosin derivative, chlorinated polypropylene, or dammar resin, and the anti-blocking agent includes at least one of silica particles, polyethylene wax, fatty acid amide, or soluble nitrocellulose.

[0023] With this configuration, the light-shielding printed matter has even better adhesion or blocking resistance.

[0024] (9) A laminate in which a sealant layer or a sealing layer is laminated on the gray ink layer of the light-shielding printed material according to any one of (1) to (8).

[0025] With this configuration, the laminate can achieve excellent shielding effects without using vinyl chloride-vinyl acetate copolymer resin, and the laminate also contains low amounts of residual organic solvents and chlorine. [Effects of the Invention]

[0026] According to the present invention, it is possible to provide light-shielding printed materials and laminates that have excellent shielding effects without using vinyl chloride-vinyl acetate copolymer resins and that have low residual organic solvent and chlorine contents. DETAILED DESCRIPTION OF THE INVENTION

[0027] <Light-blocking printed matter> A light-shielding printed matter according to one embodiment of the present invention has a substrate layer, a white ink layer formed on the substrate layer, and a gray ink layer formed on the white ink layer. The white ink layer is a layer containing a white pigment and a binder resin that satisfies the following condition 1. The gray ink layer is a layer containing a white pigment, a black pigment, and a binder resin that satisfies the following condition 2. The ratio (mass %) of the white pigment to the black pigment contained in the gray ink layer is white pigment / black pigment = 95 / 5 to 70 / 30. Each of these will be explained below. (Condition 1) The binder resin contained in the white ink layer is a polyurethane resin (A) having a urethane bond and a urea bond each having an amino group at its terminal; and at least one of a polyurethane resin (B) having a urethane bond but not a urea bond and a cellulose acetate propionate (C), The content ratio of the polyurethane resin (A), the polyurethane resin (B) and the cellulose acetate propionate (C) is (A) / ((B)+(C))=95 / 5 to 50 / 50 in terms of solid content mass ratio. (Condition 2) The binder resin contained in the gray ink layer is a polyurethane resin (A) having a urethane bond and a urea bond each having an amino group at its terminal; and at least one of a polyurethane resin (B) having a urethane bond but not a urea bond and a cellulose acetate propionate (C), The content ratio of the polyurethane resin (A), the polyurethane resin (B) and the cellulose acetate propionate (C) is (A) / ((B)+(C))=95 / 5 to 50 / 50 in terms of solid content mass ratio.

[0028] (base material layer) The substrate layer is not particularly limited, and examples thereof include a resin substrate layer and a paper substrate layer.

[0029] The resin substrate layer is a resin film such as a polyester such as polyethylene terephthalate (PET), a polyolefin such as polyethylene (PE) or polypropylene (PP), or a polyamide such as nylon; a resin film having a metal layer such as aluminum; a metal-deposited film; or a film laminated with a barrier layer.

[0030] The paper substrate includes coated paper, uncoated paper, and paper substrates obtained by laminating a resin film or the like to these.

[0031] The thickness of the substrate layer is not particularly limited.

[0032] (white ink layer) The white ink layer is a layer formed on the base layer, and contains a white pigment and a binder resin that satisfies the following condition 1. (Condition 1) The binder resin contained in the white ink layer is a polyurethane resin (A) having a urethane bond and a urea bond each having an amino group at its terminal; and at least one of a polyurethane resin (B) having a urethane bond but not a urea bond and a cellulose acetate propionate (C), The content ratio of the polyurethane resin (A), the polyurethane resin (B) and the cellulose acetate propionate (C) is (A) / ((B)+(C))=95 / 5 to 50 / 50 in terms of solid content mass ratio.

[0033] For example, the white ink layer can be formed by gravure printing a white ink composition.

[0034] The white ink composition contains a white pigment, a binder resin that satisfies the following condition 3, and an organic solvent.

[0035] The white pigment is not particularly limited. For example, the white pigment may be any white pigment commonly used in gravure printing inks, such as titanium oxide, barium sulfate, calcium carbonate, aluminum oxide, kaolin, clay, and talc. Among these, titanium oxide is preferred. Because of its excellent stability over time, titanium oxide is preferably silica alumina or organically surface-treated titanium oxide. Among these, rutile titanium oxide having an average particle size of 0.2 to 0.3 μm and an oil absorption of 17 to 35 ml / 100 g is preferred.

[0036] The content of the white pigment in the white ink composition is preferably 30 to 50% by mass.

[0037] Binder resin The binder resin satisfies the following condition 3. (Condition 3) The binder resin contained in the white ink composition is a polyurethane resin (A) having a urethane bond and a urea bond each having an amino group at its terminal; and at least one of a polyurethane resin (B) having a urethane bond but not a urea bond and a cellulose acetate propionate (C), The content ratio of the polyurethane resin (A), the polyurethane resin (B) and the cellulose acetate propionate (C) is (A) / ((B)+(C))=95 / 5 to 50 / 50 in terms of solid content mass ratio.

[0038] The polyurethane resin (A) has urethane bonds and urea bonds each having an amino group at its terminal. The polyurethane resin (A) is preferably a polyurethane resin obtained by synthesizing a urethane prepolymer by reacting an organic diisocyanate compound with a polymeric diol compound, and then reacting this with a chain extender and a reaction terminator as necessary.

[0039] The organic diisocyanate compound includes aromatic diisocyanate compounds such as tolylene diisocyanate, alicyclic diisocyanate compounds such as 1,4-cyclohexane diisocyanate and isophorone diisocyanate, aliphatic diisocyanate compounds such as hexamethylene diisocyanate, and aromatic aliphatic diisocyanate compounds such as α,α,α',α'-tetramethylxylylene diisocyanate, etc. Among these, the organic diisocyanate compound is preferably an alicyclic diisocyanate.

[0040] Examples of the polymer diol compound include polyalkylene glycols such as polyethylene glycol and polypropylene glycol; polyether diol compounds such as alkylene oxide adducts of bisphenol A with ethylene oxide, propylene oxide, etc.; polyester diols obtained by a condensation reaction of one or more dibasic acids such as adipic acid, sebacic acid, phthalic anhydride, etc. with one or more glycols such as ethylene glycol, propylene glycol, 1,4-butanediol, neopentyl glycol, 3-methyl-1,5-pentanediol, etc.; and polyester diol compounds such as polycaprolactone diols.

[0041] Furthermore, in addition to the above-mentioned polymeric diol compounds, one or more of alkanediols such as 1,4-pentanediol, 2,5-hexanediol, and 3-methyl-1,5-pentanediol, and low molecular weight diol compounds such as ethylene glycol, propylene glycol, 1,4-butanediol, and 1,3-butanediol may be used in combination.

[0042] When synthesizing a polyurethane resin, if a mixed solvent system of an ester-based solvent and an alcohol-based solvent is used as the organic solvent described below, using a polyether diol compound, preferably polypropylene glycol, as the polymer diol compound tends to increase the solubility of the resulting polyurethane resin, and tends to improve printing suitability such as gradation reproducibility and anti-fogging properties, making it possible to design a wide range of inks to suit the required performance, which is preferred.

[0043] The organic diisocyanate compound and the polymeric diol compound are preferably reacted so that the equivalent ratio of isocyanate groups to hydroxyl groups (isocyanate index) is greater than one.

[0044] The chain extender can be any known chain extender used in polyurethane resins as ink binders, and examples of such chain extenders include aliphatic diamines such as ethylenediamine, propylenediamine, tetramethylenediamine, and hexamethylenediamine; alicyclic diamines such as isophoronediamine and 4,4'-dicyclohexylmethanediamine; aromatic diamines such as toluylenediamine; aromatic aliphatic diamines such as xylenediamine; polyamines such as diethylenetriamine and triethylenetetramine; diamines having a hydroxyl group such as N-(2-hydroxyethyl)ethylenediamine, N-(2-hydroxyethyl)propylenediamine, and N,N'-di(2-hydroxyethyl)ethylenediamine; and diol compounds such as ethylene glycol, propylene glycol, 1,4-butanediol, neopentyl glycol, diethylene glycol, and triethylene glycol.

[0045] As the chain extender, it is preferable to use alicyclic diamines in combination with polyamines in a range that does not cause gelation of the resin in terms of pigment dispersibility, and diamines having a hydroxyl group in terms of resolubility.

[0046] Examples of reaction terminators to be introduced that have primary, secondary, and tertiary amino groups at the ends of the polyurethane resin include aliphatic diamines such as ethylenediamine, propylenediamine, tetramethylenediamine, and hexamethylenediamine, alicyclic diamines such as isophoronediamine and 4,4'-dicyclohexylmethanediamine, polyamines such as diethylenetriamine and triethylenetetratriamine, aromatic diamines such as toluylenediamine, aromatic aliphatic diamines such as xylenediamine, and diamines having hydroxyl groups such as N-(2-hydroxyethyl)ethylenediamine and N-(2-hydroxyethyl)propylenediamine. Among these, reaction terminators that have primary amino groups, such as polyamines, in a range that does not cause the resin to gel are preferred in terms of pigment dispersibility.

[0047] Examples of reaction terminators that introduce hydroxyl groups into polyurethane resins include alkanolamines such as monoethanolamine and diethanolamine, and diamines having hydroxyl groups such as N-(2-hydroxyethyl)ethylenediamine and N-(2-hydroxyethyl)propylenediamine. Known reaction terminators, such as monoamine compounds and monoalcohol compounds, can also be used. Specific examples of reaction terminators include monoalkylamines such as n-propylamine and n-butylamine, dialkylamines such as di-n-butylamine, and monoalcohols such as ethanol.

[0048] The polyurethane resin (A) can be obtained by reacting a diisocyanate compound with a diol compound to obtain a urethane prepolymer containing terminal isocyanate groups, and then reacting the resulting prepolymer with a chain extender and / or a reaction terminator.

[0049] The urethane group concentration of the polyurethane resin (A) is preferably 0.3 mmol / g or more, more preferably 0.5 mmol / g or more. The urethane group concentration of the polyurethane resin (A) is preferably 2.4 mmol / g or less, more preferably 1.3 mmol / g or less. When the urethane group concentration is within the above range, the polyurethane resin (A) is easy to synthesize, and the light-shielding printed matter has excellent adhesion.

[0050] The urea group concentration of the polyurethane resin (A) may be 0.3 mmol / g or more. The urea group concentration of the polyurethane resin (A) is preferably 2.0 mmol / g or less, more preferably 1.5 mmol / g or less, and even more preferably 1.2 mmol / g or less. By having the urea group concentration within the above range, the polyurethane resin (A) has printability and adhesion to films and can also be imparted with excellent lamination suitability.

[0051] The weight average molecular weight of the polyurethane resin (A) is preferably 10,000 or more, more preferably 15,000 or more, and even more preferably 20,000 or more. The weight average molecular weight of the polyurethane resin (A) is preferably 100,000 or less, more preferably 80,000 or less, and even more preferably 50,000 or less. Having a weight average molecular weight within the above range provides the polyurethane resin (A) with the advantage of being able to impart appropriate flexibility and high lamination suitability.

[0052] The polyurethane resin (A) preferably has at least one selected from a primary amino group, a secondary amino group, and a tertiary amino group at the molecular terminal, particularly at least one selected from a primary amino group and a secondary amino group at the molecular terminal, and more preferably has a hydroxyl group.

[0053] The amine value of the polyurethane resin (A) is preferably 1.0 mgKOH / g or more, more preferably 2.0 mgKOH / g or more, and even more preferably 2.5 mgKOH / g or more. Furthermore, the amine value of the polyurethane resin (A) is preferably 15.0 mgKOH / g or less, more preferably 10.0 mgKOH / g or less, and even more preferably 7.0 mgKOH / g or less. By having the amine value within the above range, the ink composition is less likely to lose stability over time, and the light-shielding printed matter exhibits excellent adhesion, lamination suitability, and blocking resistance.

[0054] The polyurethane resin (A) preferably has hydroxyl groups, more preferably at the molecular terminals and within the molecule, in view of excellent resolubility and the like.

[0055] The hydroxyl value of the polyurethane resin (A) is preferably 1.0 to 15.0 mgKOH / g.

[0056] In this embodiment, the urethane group concentration and the urea group concentration are calculated by the following formulas. (urethane group concentration) Urethane group concentration = {(W1 × OH1 + W2 × OH2 + ··· + Wi × OHi) × 100 0} / (56100×S) In the formula, each is as follows: When multiple types of polyols are used, they are calculated as polyol 1, polyol 2 to polyol i, respectively. W1: mass of polyol 1 OH1: hydroxyl value of polyol 1 W2: mass of polyol 2 OH2: hydroxyl value of polyol 2 Wi: mass of polyol i OHi: hydroxyl number of polyol i S: Mass of urethane resin solids (urea group concentration) Urea group concentration = {(X1 / M1+X2 / M2+ +Xi / Mi)×2-(W1×O H1+W2×OH2+···+Wi×OHi) / 56100}×1000 / S In the formula, the symbols are as follows: X1: Mass of diisocyanate compound 1 M1: Molecular weight of diisocyanate compound 1 X2: Mass of diisocyanate compound 2 M2: Molecular weight of diisocyanate compound 2 Xi: Mass of diisocyanate compound i Mi: Molecular weight of diisocyanate compound i W1: mass of polyol 1 OH1: hydroxyl value of polyol 1 W2: mass of polyol 2 OH2: hydroxyl value of polyol 2 Wi: mass of polyol i OHi: hydroxyl number of polyol i S: Mass of urethane resin solids

[0057] In the present embodiment, the amine value is calculated by the following method: The amine value means the amine value per 1 g of solid content, and is measured using a 0.1 N aqueous hydrochloric acid solution by potentiometric titration (for example, COMTITE (AUTO TITRATOR COM-900, BURET B-900, TITSTATION K-900), manufactured by Hiranuma Sangyo Co., Ltd.), and then calculated as a value converted into an equivalent amount of potassium hydroxide.

[0058] In consideration of environmental aspects, the polyurethane resin (A) preferably contains a biomass polyurethane resin. In the following description of the biomass polyurethane resin, descriptions common to the polyurethane resins described above will be omitted as appropriate.

[0059] Biomass polyurethane resin is a polyurethane resin containing a biomass-derived (plant-derived) component. Compared to resins using other exhaustible resources, biomass polyurethane resins can contribute more to preventing global warming and reducing environmental impact. Therefore, biomass polyurethane resins are preferably obtained by synthesizing a urethane prepolymer through a reaction between a biopolyol component and an isocyanate component, and then reacting this with a chain extender and a reaction terminator as needed. It is more preferable that the isocyanate component is a plant-derived bioisocyanate.

[0060] The biopolyol component is preferably a biopolyester polyol obtained by reacting a short-chain diol component having 2 to 4 carbon atoms with a carboxylic acid component. It is more preferable that at least one of the short-chain diol component and the carboxylic acid component of the biopolyol component is derived from a plant, and it is even more preferable that both are derived from a plant.

[0061] The plant-derived short-chain diol component having 2 to 4 carbon atoms is not particularly limited. For example, the short-chain diol component may be 1,3-propanediol, 1,4-butanediol, ethylene glycol, diethylene glycol, or the like, which are obtained from plant raw materials by the following method, or these may be used in combination.

[0062] 1,3-propanediol is produced from glycerol via 3-hydroxypropylaldehyde (HPA) by a fermentation method in which glucose is obtained by decomposing plant resources (such as corn). 1,3-propanediol compounds produced by biomethods such as the fermentation method produce useful by-products such as lactic acid, and can be produced at lower costs than 1,3-propanediol compounds produced by the EO production method.

[0063] 1,4-butanediol is produced by hydrogenating succinic acid obtained by fermenting glycol produced from plant resources, while ethylene glycol is produced from bioethanol obtained by conventional methods via ethylene.

[0064] The plant-derived carboxylic acid component is not particularly limited. Examples of the carboxylic acid component include sebacic acid, succinic acid, lactic acid, glutaric acid, and dimer acid. These may be used in combination. Among these, it is preferable that the carboxylic acid component includes at least one selected from the group consisting of sebacic acid, succinic acid, and dimer acid.

[0065] The biopolyol component is produced as a 100% plant-derived biopolyester polyol by appropriately condensing a plant-derived short-chain diol component and a plant-derived carboxylic acid component.

[0066] To obtain a biomass polyurethane resin using the above synthesis components, for example, a diisocyanate compound and a diol compound are reacted to obtain a urethane prepolymer containing terminal isocyanate groups so that the urethane group concentration is 0.3 to 2.4 mmol / g, preferably 0.5 to 1.3 mmol / g, and then a chain extender and / or a reaction terminator is reacted therewith.

[0067] The polyurethane resin (B) has a urethane bond and does not have a urea bond.

[0068] The polyurethane resin (B) is preferably a polyurethane resin having terminal hydroxyl groups that can be obtained by reacting a diisocyanate compound, a low-molecular-weight polyol compound having an average mass molecular weight of 1,000 or less, and a low-molecular-weight compound having two or more hydroxyl groups.

[0069] Examples of the diisocyanate compound include aliphatic diisocyanate compounds such as hexamethylene diisocyanate and 2,2,4-trimethylhexamethylene diisocyanate; alicyclic diisocyanate compounds such as isophorone diisocyanate, hydrogenated xylylene diisocyanate and 4,4-cyclohexylmethane diisocyanate; aromatic aliphatic diisocyanate compounds such as xylylene diisocyanate and α,α,α',α'-tetramethylxylylene diisocyanate; and aromatic diisocyanate compounds such as toluylene diisocyanate and diphenylmethane diisocyanate.

[0070] Low molecular weight polyol compounds having an average mass molecular weight of 1000 or less can be obtained by mixing one or more diol compounds such as polyalkylene glycols such as polyethylene glycol and polypropylene glycol, polyether diol compounds such as alkylene oxide adducts of bisphenol A with ethylene oxide, propylene oxide, etc., polyester diols obtained by condensation reaction of one or more dibasic acids such as adipic acid, sebacic acid, phthalic anhydride, etc. with one or more glycols such as ethylene glycol, propylene glycol, 1,4-butanediol, neopentyl glycol, 3-methyl-1,5-pentanediol, etc., and polyester diol compounds such as polycaprolactone diols.

[0071] The low-molecular-weight compound having two or more hydroxyl groups may be one or more of aliphatic polyols such as ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, hexamethylene glycol, sucrose, methylene glycol, glycerin, and sorbitol; and aromatic polyols such as bisphenol A, 4,4'-dihydroxydiphenyl, 4,4'-dihydroxydiphenyl ether, 4,4'-dihydroxydiphenyl sulfone, hydrogenated bisphenol A, and hydroquinone.

[0072] To obtain polyurethane resin (B) using the above synthesis components, it is preferable to react a diisocyanate compound with a low-molecular-weight polyol compound having an average mass molecular weight of 1000 or less and a low-molecular-weight compound having two or more hydroxyl groups so that the terminals are hydroxyl groups, so that the urethane group concentration is 2.0 to 6.0 mmol / g, preferably 3.5 to 5.5 mmol / g.

[0073] In consideration of the environment, it is preferable that the polyurethane resin (B) contains a biomass polyurethane resin. In the following explanation, explanations common to the polyurethane resins described above in relation to the polyurethane resin (A) will be omitted as appropriate.

[0074] Biomass polyurethane resin is a polyurethane resin containing biomass-derived (plant-derived) components. Biomass polyurethane resins can contribute more to preventing global warming and reducing environmental impact than those made from other exhaustible resources, and are therefore preferably biomass polyurethane resins obtainable by reacting a diisocyanate compound (biomass diisocyanate compounds are more environmentally preferable), a low-molecular-weight polyol compound containing a biomass low-molecular-weight polyol compound with an average mass molecular weight of 1,000 or less, and a compound having two or more hydroxyl groups (biomass low-molecular-weight compounds having two or more hydroxyl groups are more environmentally preferable).

[0075] The low-molecular-weight polyol compound containing a biomass low-molecular-weight polyol compound having an average mass molecular weight of 1,000 or less may be a biomass polyester polyol alone; a polyalkylene glycol other than a biomass polyester polyol, such as polyethylene glycol or polypropylene glycol; a polyether diol compound, such as an alkylene oxide adduct of bisphenol A, such as ethylene oxide or propylene oxide; a polyester diol obtained by a condensation reaction of one or more dibasic acids, such as adipic acid, sebacic acid, or phthalic anhydride, with one or more glycols, such as ethylene glycol, propylene glycol, 1,4-butanediol, neopentyl glycol, or 3-methyl-1,5-pentanediol; or a polyester diol compound, such as polycaprolactone diols, used in combination with one or more diol compounds.

[0076] Biomass polyester polyols include various polymeric diol compounds, such as polyalkylene glycols (e.g., polyethylene glycol, polypropylene glycol), polyether diol compounds (e.g., alkylene oxide adducts of bisphenol A (e.g., ethylene oxide, propylene oxide), polyester diols obtained by the condensation reaction of dibasic acids (e.g., adipic acid, sebacic acid, phthalic anhydride) with glycols (e.g., ethylene glycol, propylene glycol, 1,4-butanediol, neopentyl glycol, 3-methyl-1,5-pentanediol), and polyester diol compounds (e.g., polycaprolactone diols). At least one of these compounds is derived from plants.

[0077] The plant-derived short-chain diol component is not particularly limited, and may be, for example, 1,3-propanediol, 1,4-butanediol, ethylene glycol, or the like, which are obtained from plant raw materials by the following method.

[0078] 1,3-propanediol is produced from glycerol via 3-hydroxypropylaldehyde (HPA) by a fermentation method in which glucose is obtained by decomposing plant resources (such as corn). 1,3-propanediol compounds produced by biomethods such as the fermentation method described above are safer than 1,3-propanediol compounds produced by the EO production method, because useful by-products such as lactic acid are obtained, and production costs can be kept low. 1,4-butanediol is produced by producing glycol from plant resources, fermenting the glycol, and obtaining succinic acid, which is then hydrogenated.

[0079] Ethylene glycol is produced from bioethanol obtained by a conventional method via ethylene.

[0080] The plant-derived dicarboxylic acid component is not particularly limited. Examples of the dicarboxylic acid component include sebacic acid, succinic acid, lactic acid, glutaric acid, malic acid, and dimer acid. Among these, the dicarboxylic acid component preferably contains at least one selected from the group consisting of sebacic acid, succinic acid, and dimer acid, from the viewpoint of achieving even better blocking resistance and lamination suitability of the printed matter when the resulting adhesive composition is printed or applied to flexible packaging.

[0081] The biomass polyol component can be obtained by appropriately subjecting a plant-derived short-chain diol component and a plant-derived carboxylic acid component to a condensation reaction using a conventionally known method.

[0082] Examples of the low-molecular-weight compound having two or more hydroxyl groups include aliphatic polyols such as ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, hexamethylene glycol, sucrose, methylene glycol, glycerin, and sorbitol; and aromatic polyols such as bisphenol A, 4,4'-dihydroxydiphenyl, 4,4'-dihydroxydiphenyl ether, 4,4'-dihydroxydiphenyl sulfone, hydrogenated bisphenol A, and hydroquinone. From an environmental perspective, the low-molecular-weight compound having two or more hydroxyl groups is preferably 1,3-propanediol, 1,4-butanediol, or ethylene glycol, which can be obtained from plant materials.

[0083] Using the above synthesis components, biomass polyurethane resin (B) can be obtained by reacting a diisocyanate compound (biomass diisocyanate compounds are more preferable from an environmental perspective), a low-molecular-weight polyol compound containing a biomass low-molecular-weight polyol compound with an average mass molecular weight of 1000 or less, and a low-molecular-weight compound having two or more hydroxyl groups (biomass low-molecular-weight compounds having two or more hydroxyl groups are more preferable from an environmental perspective) so that the terminals are isocyanate groups, so that the urethane group concentration is 2.0 to 6.0 mmol / g, preferably 3.5 to 5.5 mmol / g.

[0084] The urethane group concentration of the polyurethane resin (B) is preferably 2.0 mmol / g or more, more preferably 3.5 mmol / g or more. The urethane group concentration of the polyurethane resin (B) is preferably 6.0 mmol / g or less, more preferably 5.5 mmol / g or less. When the urethane group concentration is within the above range, the polyurethane resin (B) is easy to synthesize, and the light-shielding printed matter has excellent adhesion.

[0085] The weight average molecular weight of the polyurethane resin (B) is preferably at least 1,000, and more preferably at least 2,000. The weight average molecular weight of the polyurethane resin (B) is preferably at most 6,000, and more preferably at most 5,000. When the weight average molecular weight is within the above range, the light-shielding printed matter has excellent adhesion.

[0086] The polyurethane resin (B) may not have an amine value.

[0087] The cellulose acetate propionate resin (C) may be any resin that has been conventionally used in gravure printing ink compositions.

[0088] The cellulose acetate propionate resin (C) is obtained by triesterifying cellulose with acetic acid and propionic acid, followed by hydrolysis. Commercially available cellulose acetate propionate resin (C) is generally a resin having an acetylation content of 0.6 to 2.5% by mass, a propionylation content of 42 to 46% by mass, and a hydroxyl group content of 1.8 to 5% by mass. A specific example of a commercially available cellulose acetate propionate resin (C) is cellulose acetate propionate manufactured by Kanto Chemical Co., Ltd.

[0089] The binder resin contained in the white ink composition of this embodiment contains at least one of a polyurethane resin (B) and a cellulose acetate propionate (C).

[0090] Returning to the explanation of the white ink composition as a whole, the content ratio of the polyurethane resin (A), the polyurethane resin (B), and the cellulose acetate propionate (C) in the white ink composition is preferably (A) / ((B)+(C))=95 / 5 to 50 / 50, more preferably 95 / 5 to 70 / 30, in terms of solids mass ratio. When the content ratio is within the above range, the white ink composition has excellent printability, adhesion, and lamination suitability, and has the advantage of being able to reduce residual solvent.

[0091] The white ink layer preferably contains at least one of an adhesion improver and an anti-blocking agent, and can be formed by adding at least one of an adhesion improver and an anti-blocking agent to the white ink composition. This provides the light-shielding printed matter with better adhesion or blocking resistance.

[0092] The adhesion improver preferably contains at least one of rosin, a rosin derivative, chlorinated polypropylene, and a dammar resin.

[0093] Rosin includes gum rosin, tall oil rosin, wood rosin, etc. Generally, rosin is an amber-colored, amorphous resin obtained from pine trees, and since it is obtained from nature, it is a mixture. Rosin may be isolated and used as each of its constituent components, namely, abietic acid, neoabietic acid, palustric acid, pimaric acid, isopimaric acid, sandaracopimaric acid, and dehydroabietic acid, and these are included in the definition of rosin in this embodiment.

[0094] The rosin derivative is a compound obtained by modifying the above-mentioned rosin, and examples thereof include the following.

[0095] Hydrogenated rosin: A rosin that has had hydrogen added to its conjugated double bonds (hydrogenation) to improve its weather resistance. Disproportionated rosin: Disproportionation is a modification in which two molecules of rosin react with each other, resulting in two molecules of abietic acid with conjugated double bonds, one of which becomes aromatic and the other a molecule with a single double bond. Generally, weather resistance is inferior to that of hydrogenated rosin, but it is more weather resistant than untreated rosin. Rosin-modified phenolic resin: Rosin-modified phenolic resin is often used as the main binder in offset printing inks. Rosin-modified phenolic resin can be obtained by known manufacturing methods. Rosin ester: An ester resin derived from rosin, which has long been used as a tackifier for adhesives and pressure sensitive adhesives. Rosin-modified maleic acid resin: A resin obtained by adding maleic anhydride to rosin, and may also include a resin obtained by grafting a hydroxyl group-containing compound such as glycerin through esterification with the anhydride group, if necessary. Polymerized rosin: A derivative containing dimerized resin acids derived from the natural resin rosin. In addition, known rosins and rosin derivatives can also be used.

[0096] The acid value of the rosin and rosin derivative is preferably 120 mgKOH / g or more, more preferably 160 mgKOH / g or more, thereby improving laminate strength. Furthermore, the total amount of rosin and rosin derivative used in the white ink composition is preferably 0.1 to 3.0 mass % in terms of solids mass %.

[0097] The chlorinated polypropylene preferably has a chlorination degree of 20 to 50. When the chlorination degree is within the above range, the chlorinated polypropylene has excellent compatibility with organic solvents and excellent adhesion to films. In the present embodiment, the chlorination degree is defined as the mass % of chlorine atoms in the chlorinated polypropylene resin.

[0098] The chlorinated polypropylene is preferably a modified or unmodified chlorinated polypropylene having a mass average molecular weight of 5,000 to 200,000. When the mass average molecular weight is within the above range, the chlorinated polypropylene has excellent adhesive properties and excellent solubility in organic solvents.

[0099] The content of the chlorinated polypropylene in the white ink composition is preferably 0.1 to 3.0 mass % in terms of solid mass %.

[0100] Dammar resin is a type of natural resin derived from plants, and is obtained from Dipterocarpaceae or Burseraceae plants that grow in Southeast Asia, such as Malaysia and Indonesia. When used, dammar resin is dissolved in an appropriate organic solvent to form a varnish. Dammar resin does not contain chlorine. Therefore, dammar resin can eliminate or reduce chlorine compared to the use of chlorinated polyolefin resin in ink compositions.

[0101] The content of the dammar resin in the white ink composition is preferably 3.0 mass % or less in terms of solid mass %.

[0102] The anti-blocking agent is preferably silica particles, polyethylene wax, fatty acid amide, cellulose acetate butyrate, cellulose acetate propionate, soluble nitrocellulose, etc., and more preferably contains at least one of silica particles, polyethylene wax, fatty acid amide, and soluble nitrocellulose. Depending on the type of pigment, the anti-blocking agent preferably further contains cellulose acetate butyrate and soluble nitrocellulose.

[0103] Examples of silica particles include natural products, synthetic products, crystalline, non-crystalline, hydrophobic, and hydrophilic silica particles.

[0104] The silica particles preferably have an average particle size of 1.0 to 5.0 μm. The average particle size of the silica particles means the particle size at 50% cumulative value (D50) in the particle size distribution, and can be determined by the Coulter counter method.

[0105] The silica particles may be hydrophilic silica having hydrophilic functional groups on the surface, or may be hydrophobic silica in which the hydrophilic functional groups have been modified with alkylsilane or the like to make them hydrophobic. The silica particles are preferably hydrophilic silica. An ink composition containing hydrophilic silica particles promotes wetting and spreading of the ink composition during overprinting, improving the overprinting effect (hereinafter sometimes referred to as "trapping property").

[0106] The content of silica particles in the white ink composition is preferably more than 0 and not more than 3.0% by mass, and more preferably 0.1 to 1.0% by mass.

[0107] The polyethylene wax preferably has an average particle size in the range of 1.0 to 20 μm. The average particle size refers to the particle size measured with a Microtrac UPA manufactured by Honeywell Corporation. When the particle size of the polyethylene wax is within the above range, the ink composition has excellent smoothness, anti-blocking properties, and trapping properties.

[0108] The content of the polyethylene wax in the white ink composition is preferably 0.1 to 1.5% by mass. When the content of the polyethylene wax is within the above range, the ink composition has excellent gloss.

[0109] Nitrogen cellulose is obtained as a nitric acid ester by reacting native cellulose with nitric acid, substituting nitric acid groups for three hydroxyl groups in the six-membered ring of the anhydroglucopyranose group in the native cellulose. Nitrogen cellulose preferably has a nitrogen content of 10 to 13% and an average degree of polymerization of 35 to 90. Specific examples of nitrocellulose include SS1 / 2, SS1 / 4, SS1 / 8, TR1 / 16, and NCRS-2 (manufactured by KOREA CNC LTD).

[0110] The content of soluble nitrocellulose in the white ink composition is preferably 0.1 to 2.0% by mass.

[0111] Cellulose acetate butyrate resin is obtained by triesterifying cellulose with acetic acid and butyric acid, followed by hydrolysis. Cellulose acetate butyrate resins are generally commercially available as resins with 2 to 30% by mass acetylation, 17 to 53% by mass butyrylation, and 1 to 5% hydroxyl groups.

[0112] The content of the cellulose acetate butyrate resin in the white ink composition is preferably 0.1 to 3.0% by mass.

[0113] The fatty acid amide is not particularly limited as long as it has an amide group and a residue obtained by removing an acid group from a fatty acid. Examples of the fatty acid amide include monoamides, substituted amides, bisamides, methylol amides, and ester amides. Among these, the fatty acid amide is preferably at least one selected from the group consisting of monoamides, substituted amides, and bisamides, because this improves blocking resistance.

[0114] The content of the fatty acid amide in the white ink composition is preferably 0.01 to 1% by mass.

[0115] The monoamide is represented by the following general formula (1). General formula (1) R1-CONH2 (In the formula, R1 represents the residue obtained by removing COOH from a fatty acid.)

[0116] Specific examples of monoamides include lauric acid amide, palmitic acid amide, stearic acid amide, behenic acid amide, hydroxystearic acid amide, oleic acid amide, and erucic acid amide.

[0117] The substituted amide is represented by the following general formula (2). General formula (2) R2-CONH-R3 (In the formula, R2 and R3 represent the residue obtained by removing COOH from a fatty acid, and may be the same or different.)

[0118] Specific examples of the substituted amides include N-oleyl palmitic acid amide, N-stearyl stearic acid amide, N-stearyl oleic acid amide, N-oleyl stearic acid amide, and N-stearyl erucic acid amide.

[0119] The bisamide is represented by the following general formula (3) or (4). General formula (3) R4-CONH-R5-HNCO-R6 General formula (4) R7-NHCO-R8-CONH-R9 (In the formula, R4, R6, R7, and R9 represent residues obtained by removing COOH from fatty acids and may be the same or different. R5 and R8 represent alkylene or arylene groups having 1 to 10 carbon atoms and may be the same or different.)

[0120] Specific examples of bisamides include methylene bisstearic acid amide, ethylene biscapric acid amide, ethylene bislauric acid amide, ethylene bisstearic acid amide, ethylene bishydroxystearic acid amide, ethylene bisbehenic acid amide, hexamethylene bisstearic acid amide, hexamethylene bisbehenic acid amide, hexamethylene hydroxystearic acid amide, ethylene bisoleic acid amide, ethylene biserucic acid amide, hexamethylene bisoleic acid amide, N,N'-distearyl adipamide, N,N'-distearyl sebacic acid amide, N,N'-dioleyl adipamide, and N,N'-dioleyl sebacic acid amide.

[0121] Methylolamide is represented by the following general formula (5). General formula (5) R10-CONHCH2OH (In the formula, R10 represents a residue obtained by removing COOH from a fatty acid.)

[0122] Specific examples of the methylol amide include methylol palmitic acid amide, methylol stearic acid amide, methylol behenic acid amide, methylol hydroxystearic acid amide, methylol oleic acid amide, and methylol erucic acid amide.

[0123] The ester amide is represented by the following general formula (6). General formula (6) R11-CONH-R12-OCO-R13 (In the formula, R11 and R13 represent a residue obtained by removing COOH from a fatty acid and may be the same or different, and R12 represents an alkylene group or arylene group having 1 to 10 carbon atoms.)

[0124] Specific examples of ester amides include stearylamide ethyl stearate and oleylamide ethyl stearate.

[0125] The melting point of the fatty acid amide is preferably 50°C to 150°C.

[0126] The fatty acids constituting the fatty acid amide are preferably saturated fatty acids having 12 to 22 carbon atoms and / or unsaturated fatty acids having 16 to 25 carbon atoms, and more preferably saturated fatty acids having 16 to 18 carbon atoms and / or unsaturated fatty acids having 18 to 22 carbon atoms. The saturated fatty acids are preferably lauric acid, palmitic acid, stearic acid, behenic acid, and hydroxystearic acid. The unsaturated fatty acids are preferably oleic acid and erucic acid.

[0127] Organic solvents The white ink composition contains an organic solvent. Examples of the organic solvent include ketone-based organic solvents such as acetone, methyl ethyl ketone, and methyl isobutyl ketone; ester-based organic solvents such as methyl acetate, ethyl acetate, n-propyl acetate, n-butyl acetate, and isobutyl acetate; alcohol-based organic solvents such as methanol, ethanol, n-propanol, isopropanol, and butanol; and hydrocarbon solvents such as toluene and methylcyclohexane. Among these, from an environmental perspective, the organic solvent is preferably a mixed solvent of an ester-based organic solvent, an alcohol-based organic solvent, and a ketone-based organic solvent, and more preferably a mixed solvent of an ester-based organic solvent and an alcohol-based organic solvent, which is more environmentally friendly.

[0128] The white ink composition preferably contains water. By containing water, the white ink composition can reduce printing defects caused by static electricity, and is excellent in preventing plate fogging and cell reproducibility.

[0129] The content of water in the white ink composition is preferably 10% by mass or less, and more preferably 0.1 to 5.0% by mass.

[0130] The white ink composition may further contain various additives such as a pigment dispersant, an antistatic agent, a plasticizer, an antifoaming agent, etc. The white ink composition may also contain a silane coupling agent.

[0131] There are no particular limitations on the method for producing the white ink composition. As an example, the white ink composition can be produced by kneading a mixture of a white pigment, a binder resin, an organic solvent, and, if necessary, a pigment dispersant, etc., using a high-speed mixer, a ball mill, a sand mill, an attritor, etc., and then adding and mixing the remaining materials, such as predetermined additives.

[0132] Returning to the explanation of the white ink layer as a whole, the film thickness of the white ink layer is preferably 2 μm or more, more preferably 3 μm or more. Also, the film thickness of the white ink layer is preferably 10 μm or less, more preferably 9 μm or less. When the film thickness of the white ink layer is within the above range, the light-shielding printed matter has excellent shielding properties, high whiteness, and excellent visibility of characters, etc.

[0133] (Gray ink layer) The gray ink layer is a layer formed on the white ink layer, and contains a white pigment, a black pigment, and a binder resin that satisfies the following condition 2. The ratio (mass %) of the white pigment to the black pigment contained in the gray ink layer is white pigment / black pigment = 95 / 5 to 70 / 30. (Condition 2) The binder resin contained in the gray ink layer is a polyurethane resin (A) having a urethane bond and a urea bond each having an amino group at its terminal; and at least one of a polyurethane resin (B) having a urethane bond but not a urea bond and a cellulose acetate propionate (C), The content ratio of the polyurethane resin (A), the polyurethane resin (B) and the cellulose acetate propionate (C) is (A) / ((B)+(C))=95 / 5 to 50 / 50 in terms of solid content mass ratio.

[0134] The gray ink layer can be formed by gravure printing a gray ink composition.

[0135] For example, the gray ink composition is a mixture of a white ink composition and a black ink composition. The white ink composition can be the same as that described for the white ink layer.

[0136] The black ink composition contains a black pigment, a binder resin that satisfies the following condition 4, and an organic solvent. (Condition 4) The binder resin contained in the black ink composition is a polyurethane resin (A) having a urethane bond and a urea bond each having an amino group at its terminal; and at least one of a polyurethane resin (B) having a urethane bond but not a urea bond and a cellulose acetate propionate (C), The content ratio of the polyurethane resin (A), the polyurethane resin (B) and the cellulose acetate propionate (C) is (A) / ((B)+(C))=95 / 5 to 50 / 50 in terms of solid content mass ratio.

[0137] Black pigment The black pigment is not particularly limited. For example, the black pigment may be any black pigment commonly used in gravure printing inks, such as carbon black and titanium black. Of these, carbon black is preferred.

[0138] The carbon black is not particularly limited.

[0139] The content of the black pigment in the black ink composition is preferably 7% by mass or more, more preferably 9% by mass or more. The content of the black pigment in the black ink composition is preferably 17% by mass or less, more preferably 15% by mass or less. By having the carbon black content within the above range, the black ink composition has excellent printability and excellent lamination suitability.

[0140] Binder resin The binder resin satisfies the following condition 4. (Condition 4) The binder resin contained in the black ink composition is a polyurethane resin (A) having a urethane bond and a urea bond each having an amino group at its terminal; and at least one of a polyurethane resin (B) having a urethane bond but not a urea bond and a cellulose acetate propionate (C), The content ratio of the polyurethane resin (A), the polyurethane resin (B) and the cellulose acetate propionate (C) is (A) / ((B)+(C))=95 / 5 to 50 / 50 in terms of solid content mass ratio.

[0141] The polyurethane resin (A), the polyurethane resin (B) and the cellulose acetate propionate (C) are the same as those described above in relation to the white ink composition.

[0142] The content ratio of the polyurethane resin (A), the polyurethane resin (B), and the cellulose acetate propionate (C) is preferably (A) / ((B)+(C))=95 / 5 to 50 / 50, more preferably 95 / 5 to 70 / 30, by solids mass ratio. When the content ratio is within the above range, the black ink composition has excellent printability, adhesion, and lamination suitability, and can reduce residual solvent.

[0143] The black ink composition may also contain the components (adhesion improver, antiblocking agent, organic solvent, water, and other optional components) described above in relation to the white ink composition.

[0144] There are no particular limitations on the method for producing the black ink composition. As an example, the black ink composition can be obtained by grinding a mixture of a black pigment, a binder resin, an organic solvent, and, if necessary, a pigment dispersant, etc., using a high-speed mixer, a ball mill, a sand mill, an attritor, etc., and then adding and mixing the remaining materials, such as predetermined additives.

[0145] The gray ink composition can be obtained by mixing the black ink composition and the white ink composition with stirring.

[0146] In this embodiment, the ratio (mass %) of the white pigment used in the white ink composition to obtain the gray ink composition and the black pigment used in the black ink composition is white pigment / black pigment = 95 / 5 to 70 / 30. The gray ink layer can be formed by gravure printing the gray ink composition, and the ratio (mass %) of the white pigment to the black pigment is white pigment / black pigment = 95 / 5 to 70 / 30. By having the ratio of the white pigment to the black pigment within the above range, the light-shielding printed matter does not impair design (visibility) while maintaining high hiding power.

[0147] Returning to the explanation of the gray ink layer as a whole, the thickness of the gray ink layer is preferably 1 μm or more, more preferably 2 μm or more. Furthermore, the thickness of the gray ink layer is preferably 5 μm or less, more preferably 4 μm or less. By having the thickness of the gray ink layer within the above range, the light-shielding printed matter maintains high hiding power without impairing design (visibility).

[0148] Returning to the explanation of the light-blocking printed material as a whole, the light-blocking printed material of this embodiment can be produced by printing a white ink composition one or more times on one side of a substrate layer using a gravure printer, and then printing a gray ink composition one or more times on the white ink layer using a gravure printer. The obtained light-blocking printed material exhibits excellent shielding effects even without using a vinyl chloride-vinyl acetate copolymer resin. In addition, the light-blocking printed material contains low amounts of residual organic solvents and chlorine.

[0149] <Laminate> A laminate according to one embodiment of the present invention is a laminate in which a sealant layer or a sealing layer is laminated on the gray ink layer of the above-described light-shielding printed material.

[0150] The sealant layer can be formed by laminating a resin film or the like using various lamination methods.

[0151] Lamination methods include extrusion lamination, in which an anchor coating agent is applied to the surface of the gray ink layer and then a molten polymer is laminated, and dry lamination, in which an adhesive is applied to the surface of the gray ink layer and then a film-like polymer is laminated. Extrusion lamination is a method in which an anchor coating agent such as a titanium-based, urethane-based, imine-based, or polybutadiene-based agent is applied to the surface of the gray ink layer as needed, and then a molten polymer is laminated using a known extrusion laminator.

[0152] The raw materials constituting the sealant layer include linear low-density polyethylene film, unstretched polypropylene film, etc. in the dry lamination method, and molten resins such as low-density polyethylene, ethylene-vinyl acetate copolymer, and low-density polypropylene in the extrusion lamination method.

[0153] The thickness of the sealant layer is not particularly limited, and is, for example, 5 to 100 μm.

[0154] The sealing layer is formed by applying a heat sealing agent or a hot melt agent.

[0155] The thickness of the sealing layer is not particularly limited. For example, the thickness of the sealing layer is preferably 1 to 50 μm when a hot melt agent is applied, and is preferably 0.01 to 30 μm when a heat sealing agent is applied.

[0156] The laminate of this embodiment provides excellent shielding effect without using vinyl chloride-vinyl acetate copolymer resin, and the laminate also contains low amounts of residual organic solvents and chlorine. [Example]

[0157] The present invention will be described in more detail below with reference to examples. The present invention is not limited to these examples. Unless otherwise specified, "%" means "% by mass" and "parts" means "parts by mass."

[0158] The raw materials and preparation methods used are shown below. <Polyurethane resin (A)>

[0159] (Polyurethane Resin Varnish A-1) A four-neck flask equipped with a stirrer, thermometer, Dimroth reaction system, and nitrogen gas inlet tube was charged with 100 parts by mass of 3-methyl-1,5-pentyleneadipate diol with an average molecular weight of 5000 and 8.9 parts by mass of isophorone diisocyanate, and the mixture was allowed to react for 5 hours at 95 to 105°C while introducing nitrogen gas. After cooling, 196 parts by mass of propyl acetate was added to dissolve uniformly, and 65 parts of isopropyl alcohol and 2.0 parts of isophorone diamine were added to extend the chain. 0.35 parts of monoethanolamine were then added, followed by 0.51 parts of isophorone diamine to terminate the reaction, yielding polyurethane resin varnish A-1 (solids content 30%).

[0160] (Polyurethane Resin Varnish A-2) A four-neck flask equipped with a stirrer, thermometer, Dimroth reaction system, and nitrogen gas inlet tube was charged with 100 parts by mass of 3-methyl-1,5-pentyleneadipate diol with an average molecular weight of 3,000 and 13 parts by mass of isophorone diisocyanate, and the mixture was allowed to react for 5 hours at 95 to 105°C while introducing nitrogen gas. After cooling, 206 parts by mass of propyl acetate was added and dissolved uniformly, and 69 parts of isopropyl alcohol and 3.2 parts of isophorone diamine were added to extend the chain. 0.35 parts of monoethanolamine were then added, followed by 0.5 parts of isophorone diamine to terminate the reaction, yielding polyurethane resin varnish A-2 (solids content 30%).

[0161] (Polyurethane Resin Varnish A-3) A four-neck flask equipped with a stirrer, thermometer, Dimroth reaction system, and nitrogen gas inlet tube was charged with 100 parts by mass of 3-methyl-1,5-pentylene adipate diol with an average molecular weight of 1,000 and 42 parts by mass of isophorone diisocyanate, and the mixture was allowed to react for 5 hours at 95 to 105°C while introducing nitrogen gas. After cooling, 274 parts by mass of propyl acetate was added to dissolve uniformly, and 91.4 parts of isopropyl alcohol and 13.3 parts of isophorone diamine were added to extend the chain. 0.5 parts of monoethanolamine were then added, followed by 0.74 parts of isophorone diamine to terminate the reaction, yielding polyurethane resin varnish A-3 (solids content 30%).

[0162] (Polyurethane Resin Varnish A-4) A four-neck flask equipped with a stirrer, thermometer, Dimroth filter, and nitrogen gas inlet tube was charged with 100 parts by weight of sebacic acid (derived from castor oil) / succinic acid (derived from plant) = 70 / 30 (mass ratio) and 1,3-propanediol (derived from plant), an average molecular weight of 1000, and 42 parts by weight of isophorone diisocyanate, and the mixture was reacted for 5 hours at 95 to 105 ° C. After cooling, 274 parts by weight of propyl acetate was added to dissolve uniformly, 91.4 parts of isopropyl alcohol and 13.3 parts of isophorone diamine were added to extend the chain, and 0.5 parts of monoethanolamine was added, followed by 0.74 parts of isophorone diamine to terminate the reaction, yielding polyurethane resin varnish A-4 (solids content 30%).

[0163] (Polyurethane Resin Varnish A-5) A four-neck flask equipped with a stirrer, thermometer, Dimroth stirrer, and nitrogen gas inlet tube was charged with 100 parts by mass of 3-methyl-1,5-pentyleneadipate diol with an average molecular weight of 500 and 80 parts by mass of isophorone diisocyanate, and the mixture was allowed to react for 5 hours at 95 to 105°C while introducing nitrogen gas. After cooling, 360 parts by mass of propyl acetate was added to dissolve uniformly, and 120 parts by mass of isopropyl alcohol and 24.5 parts by mass of isophorone diamine were added to extend the chain. 0.69 parts by mass of monoethanolamine was then added, followed by 1.0 part by mass of isophorone diamine to terminate the reaction, yielding polyurethane resin varnish A-5 (solids content 30%).

[0164] <Polyurethane resin (B)> (Polyurethane Resin Varnish B-1) A four-neck flask equipped with a stirrer, thermometer, Dimroth stirrer, and nitrogen gas inlet tube was charged with 60 parts by mass of 3-methyl-1,5-pentylene adipate diol with an average molecular weight of 1000, 13.5 parts by mass of polypropylene glycol with an average molecular weight of 400, 20 parts by mass of monoethylene glycol, 6.5 parts by mass of propylene glycol, and 89 parts by mass of isophorone diisocyanate, and the mixture was reacted for 3 hours at 95 to 105°C while introducing nitrogen gas. After cooling, 330 parts by mass of propyl acetate was added and dissolved uniformly, and 110 parts by mass of isopropyl alcohol was added to obtain polyurethane resin varnish B-1 (solids content 30%).

[0165] (Polyurethane Resin Varnish B-2) A four-neck flask equipped with a stirrer, thermometer, Dimroth filter, and nitrogen gas inlet tube was charged with 60 parts by mass of polyester polyol with an average molecular weight of 1000 obtained from sebacic acid (derived from castor oil) / succinic acid (derived from plant) = 70 / 30 (mass ratio) and 1,3-propanediol (derived from plant), 13.5 parts by mass of polypropylene glycol with an average molecular weight of 400, 20 parts by mass of monoethylene glycol, 6.5 parts by mass of propylene glycol, and 89 parts by mass of isophorone diisocyanate, and the mixture was reacted for 3 hours at 95 to 105 ° C. while introducing nitrogen gas. After cooling, 330 parts by mass of propyl acetate was added and dissolved uniformly, and 110 parts by mass of isopropyl alcohol was added to obtain polyurethane resin varnish B-2 (solids content 30%).

[0166] (Polyurethane Resin Varnish B-3) A four-neck flask equipped with a stirrer, thermometer, Dimroth stirrer, and nitrogen gas inlet tube was charged with 75 parts by weight of 3-methyl-1,5-pentylene adipate diol with an average molecular weight of 1,000, 10 parts by weight of polypropylene glycol with an average molecular weight of 400, 5 parts by weight of monoethylene glycol, 5 parts by weight of propylene glycol, and 42 parts by weight of isophorone diisocyanate, and the mixture was reacted for 3 hours at 95 to 105°C while introducing nitrogen gas. After cooling, 248 parts by weight of propyl acetate was added and dissolved uniformly, and 83 parts by weight of isopropyl alcohol was added to obtain polyurethane resin varnish B-3 (solids content 30%).

[0167] The properties of the polyurethane resin (A) varnish and the polyurethane resin (B) varnish are shown in Table 1 below.

[0168] [Table 1]

[0169] (Cellulose acetate propionate (C)) 20 parts by mass of cellulose acetate propionate (C) (number average molecular weight 25,000, propionyl 43-47%, manufactured by Kanto Chemical Co., Inc.) was dissolved in a mixed solvent of 20 parts by mass of isopropyl alcohol, 20 parts by mass of propyl acetate, and 40 parts by mass of ethyl acetate to obtain a cellulose acetate propionate (CAP) solution with a solid content of 20%.

[0170] (pigment) Titanium oxide (R-960, oil absorption capacity 18.7 ml / 100 g, manufactured by DuPont) Carbon black (acidic carbon black, particle size 40 nm, DBP oil absorption 47 ml / 100 g, specific surface area 60 m 2 / g, pH 2.8) (Vinyl chloride / vinyl acetate resin) Vinyl chloride-vinyl acetate copolymer (Solvine TA-3, manufactured by Nissin Chemical Industry Co., Ltd.) (adhesion improver) Polymerized rosin: Acid value 160mgKOH / g Chlorinated polypropylene 40 parts by mass of chlorinated polypropylene (solid content 50%) with a degree of chlorination of 40% and a number average molecular weight of 100,000 and 60 parts by mass of methylcyclohexane were mixed and stirred to obtain chlorinated polypropylene with a solid content of 20%. (Anti-blocking agent) Silica particles: average particle size 4.5 μm (Polyethylene wax) Polyethylene wax: average particle size 12 μm (fatty acid amides) Ethylenebisstearamide

[0171] (mixture) Mass ratio: ethyl acetate / propyl acetate / IPA (isopropyl alcohol) = 50 / 25 / 25

[0172] (base material) OPP: Corona discharge treated biaxially oriented polypropylene film, P-2161, thickness 25 μm, manufactured by Toyobo Co., Ltd. PET: Polyethylene terephthalate film with corona discharge treatment on one side, Toyobo Co., Ltd., E-5102, thickness 12 μm NY: Nylon film, N-1102, thickness 15 μm, manufactured by Toyobo Co., Ltd.

[0173] <Production Examples of White Ink Compositions (W1 to W9)> Titanium oxide and polyurethane resin varnish (A) were kneaded using a paint conditioner manufactured by Red Devil Co., Ltd. in the amounts shown in Table 2 below, and polyurethane resin varnish (B), cellulose acetate propionate (C), adhesion improver, anti-blocking agent, mixed liquid, and water were then added to obtain the white ink compositions of the examples shown in Table 2.

[0174] <Method for producing comparative white ink composition (W10)> Titanium oxide, polyurethane resin varnish (A), and vinyl chloride-vinyl acetate copolymer were kneaded using a paint conditioner manufactured by Red Devil Co., Ltd. in the amounts shown in Table 2, and then an adhesion improver, anti-blocking agent, mixed liquid, and water were added to obtain the comparative white ink composition shown in Table 2.

[0175] [Table 2]

[0176] <Production Examples of Black Ink Compositions (B1 to B9) for Preparing the Gray Ink Compositions of the Examples> Carbon black and polyurethane resin varnish (A) were kneaded using a paint conditioner manufactured by Red Devil Co., Ltd. in the amounts shown in Table 3, and polyurethane resin varnish (B), cellulose acetate propionate (C), an adhesion improver, an anti-blocking agent, a mixed liquid, and water were then added to obtain black ink compositions for use in preparing the gray ink compositions of the examples shown in Table 3.

[0177] <Method for producing black ink composition (B10) for producing comparative gray ink composition> Carbon black, polyurethane resin varnish (A), and vinyl chloride-vinyl acetate copolymer were mixed in the amounts shown in Table 3 using a paint conditioner manufactured by Red Devil Co., Ltd., and then an adhesion improver, an anti-blocking agent, a mixed liquid, and water were added to obtain a black ink composition for use in preparing the gray ink composition of the comparative example shown in Table 3.

[0178] [Table 3]

[0179] <Method for producing gray ink compositions (G1 to G13) of Examples and Comparative Examples> The white ink composition and the black ink composition were stirred with a stirrer so as to obtain the combination and ratio shown in Table 4, thereby obtaining a gray ink composition.

[0180] [Table 4]

[0181] <Evaluation method and criteria> Residual solvent (mg / m) was evaluated using the following method. 2 ), shielding properties, whiteness, adhesion, and blocking resistance were evaluated. The results are shown in Table 5. In the following evaluations, one of OPP, PET, and NY film was used as the substrate, and it was confirmed that equivalent results could be obtained even with substrates that did not use OPP, PET, or NY film. (residual solvent) Using a gravure printing machine equipped with a Direct 175LPI 28μm gravure printing plate, the white ink composition obtained above was printed on an OPP film at a printing speed of 100m / min with hot air at 55°C (air volume 80%), and the same white ink composition as above was printed on the white ink layer again in the same manner, and the same gray ink composition obtained above was printed on the white ink layer in the same manner. The coating area of ​​the obtained light-shielding film was 0.2m 2 The printed matter was cut into pieces so that they would fit in the printed area, placed in a 500 ml flask, and then sealed. The material was heated in an oven at 80°C for 10 minutes to evaporate the solvent remaining in the printed matter. 1 ml of gas was sampled from the flask and analyzed by gas chromatography to determine the amount of residual solvent per unit area (mg / m 2 ) was measured, and the residual solvent was evaluated based on the following criteria. (Evaluation criteria) ○: Residual solvent is 10 mg / m 2 It was less than. △: Residual solvent is 10 mg / m 2 15 mg / m or more 2 It was less than. ×: Residual solvent is 15 mg / m 2 That was all.

[0182] (shielding property) Using a gravure printing press equipped with a Direct 175LPI 28μm gravure printing plate, the white ink composition obtained above was printed onto PET at a printing speed of 100 m / min using hot air at 55°C (80% airflow). The same white ink composition as above was then printed on the white ink layer in the same manner, and the gray ink composition obtained above was then printed on the white ink layer in the same manner. The resulting laminates were then laminated with RXC-22 (Mitsui Chemicals Tocello Co., Ltd.) sealant. Three 2cm x 3cm sample pieces were cut from each laminate to prepare them. Total light transmittance was measured using a haze meter (HAZE-GARD II, Toyo Seiki Seisakusho Co., Ltd.) according to JIS K 7361-1·1997, and the average value was evaluated. (Evaluation criteria) ◯: The total light transmittance was 3% or less. △: The total light transmittance was 3% or more and less than 5%. ×: The total light transmittance was 5% or more.

[0183] (whiteness) To measure light transmittance, the white ink composition obtained above was printed on PET at a printing speed of 100 m / min using a gravure printing machine equipped with a Direct 175LPI 28μm gravure printing plate and hot air at 55°C (air volume 80%). The same white ink composition as above was printed on the white ink layer in the same manner, and the gray ink composition obtained above was printed on the white ink layer in the same manner. Thereafter, a sealant RXC-22 (manufactured by Mitsui Chemicals Tocello Co., Ltd.) was laminated, and the date was printed with a black ink composition on the substrate side of each laminate, and the visibility of the date was judged visually. (Evaluation criteria) ○: The date was clearly visible. △: The date was visible if you looked closely. ×: I couldn't see the date.

[0184] (Adhesiveness) Using a gravure printing press equipped with a Direct 175LPI 28µm gravure printing plate, the white ink composition obtained above was printed on OPP at a printing speed of 100m / min with hot air at 55°C (air volume 80%), the same white ink composition as above was printed on the white ink layer in the same manner, and the gray ink composition obtained above was printed on the white ink layer in the same manner. Immediately after printing, cellophane tape was applied to the printed surface of each print, and when peeled off, the adhesion was evaluated from the ratio of the area of ​​the ink film peeled off from the substrate. (Evaluation criteria) ○: The ink film did not peel off at all. △: The ink film peeled off in an area of ​​less than 20%. ×: The ink film peeled off over 20% or more of the area.

[0185] (blocking resistance) Using a gravure printing machine equipped with a 175 LPI 28 μm gravure printing plate, the white ink composition obtained above was printed on OPP at a printing speed of 100 m / min with hot air at 55°C (air volume 80%), and the same white ink composition as above was printed on the white ink layer again in the same manner, and the gray ink composition obtained above was printed on the white ink layer in the same manner. For each printed product, the printed surface of each printed product that had been left for one day and the untreated side of the film were aligned, and the resulting mixture was then dried at 15 kg / cm 2 After leaving the film at 40°C for 12 hours under a load of 1.0 g, the blocking resistance was evaluated based on the state of each film when peeled off. (Evaluation criteria) ◯: There was absolutely no resistance when the film was peeled off, and the ink did not peel off from the printed surface. △: There was resistance when peeling off the film, but the ink did not peel off from the printed surface. ×: There was resistance when peeling off the film, and the ink peeled off from the printed surface.

[0186] [Table 5]

[0187] As shown in Table 5, the light-shielding printed material of the present invention exhibited excellent light-shielding effect without using vinyl chloride-vinyl acetate copolymer resin, and had low residual organic solvent and chlorine content.

Claims

1. A light-shielding printed matter having a base layer, a white ink layer formed on the base layer, and a gray ink layer formed on the white ink layer, The white ink layer is a layer containing a white pigment and a binder resin that satisfies the following condition 1: The gray ink layer is a layer containing a white pigment, a black pigment, and a binder resin that satisfies the following condition 2: A light-shielding printed matter, wherein the ratio (mass %) of the white pigment to the black pigment contained in the gray ink layer is white pigment / black pigment = 95 / 5 to 70 / 30. (Condition 1) The binder resin contained in the white ink layer is a polyurethane resin (A) having a urethane bond and a urea bond each having an amino group at its terminal; and at least one of a polyurethane resin (B) having a urethane bond but not a urea bond and a cellulose acetate propionate (C), The content ratio of the polyurethane resin (A), the polyurethane resin (B) and the cellulose acetate propionate (C) is (A) / ((B)+(C))=95 / 5 to 50 / 50 in terms of solid content mass ratio. (Condition 2) The binder resin contained in the gray ink layer is a polyurethane resin (A) having a urethane bond and a urea bond each having an amino group at its terminal; and at least one of a polyurethane resin (B) having a urethane bond but not a urea bond and a cellulose acetate propionate (C), The content ratio of the polyurethane resin (A), the polyurethane resin (B) and the cellulose acetate propionate (C) is (A) / ((B)+(C))=95 / 5 to 50 / 50 in terms of solid content mass ratio.

2. The thickness of the white ink layer is 2 to 10 μm, 2. The light-shielding printed matter according to claim 1, wherein the gray ink layer has a thickness of 1 to 5 μm.

3. The polyurethane resin (A) has a urethane group concentration of 0.3 to 2.4 mmol / g, 3. The light-shielding printed matter according to claim 1, wherein the polyurethane resin (B) has a urethane group concentration of 2.0 to 6.0 mmol / g.

4. 3. The light-shielding printed matter according to claim 1, wherein the polyurethane resin (B) has a mass average molecular weight of 1,000 to 6,000.

5. 3. The light-shielding printed matter according to claim 1, wherein the polyurethane resin (A) has an amine value of 1.0 to 15.0 mgKOH / g.

6. 3. The light-shielding printed matter according to claim 1, wherein at least one of the polyurethane resin (A) and the polyurethane resin (B) is a biomass polyurethane resin.

7. 3. The light-shielding printed matter according to claim 1, wherein the white ink composition contains at least one of an adhesion improver and an anti-blocking agent.

8. the adhesion improver includes at least one of rosin, a rosin derivative, chlorinated polypropylene, and a dammar resin; 8. The light-shielding printed matter according to claim 7, wherein the anti-blocking agent includes at least one of silica particles, polyethylene wax, fatty acid amide, and soluble nitrocellulose.

9. A laminate comprising a sealant layer or a sealing layer laminated on the gray ink layer of the light-shielding printed material according to claim 1 or 2.

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