Liquid ink composition for laminate film, laminated body obtained using said liquid ink composition for laminate film, recycled material using said laminated body, method for producing recycled substrate using said laminated body, and method for producing recycled plastic pellet using said recycled substrate

Abstract

Provided are: a liquid ink resin composition having excellent blocking resistance, adhesion to substrates, (extrusion) lamination strength and two-component stability; and a laminated body and recycled material comprising said liquid ink composition.　This liquid ink composition for a laminate film contains at least a binder resin, silica and an organic solvent. The binder resin contains a polyurethane resin in which the amine value of solid content is 0.1 mg KOH / g-10 mg KOH / g.

Description

Liquid ink composition for laminate film, laminate using said liquid ink composition for laminate film, recycled material using said laminate, method for producing recycled substrate using said laminate, and method for producing recycled plastic pellets using said recycled substrate

[0001] The present invention relates to a liquid ink composition for laminate films, which is used to form a primer layer that can be detached from a substrate, a laminate using the liquid ink composition for laminate films, a recycled material using the laminate, a method for producing a recycled substrate using the laminate, and a method for producing recycled plastic pellets using the recycled substrate.

[0002] Gravure inks and flexographic inks are widely used to impart aesthetic appeal and functionality to printed substrates. When printed substrates are used as packaging materials, particularly food packaging, they are typically laminated. In this case, various printing methods are used for various printed substrates and lamination processes, such as front-side printing, in which printing is performed on the front side of a material such as a plastic film, or reverse printing, in which the orientation or color order of the printed image is reversed, depending on the type of contents or intended use. Conventionally, inks used in such lamination processes have commonly utilized a combination of polyurethane resin and vinyl chloride-vinyl acetate copolymer resin as a binder resin that combines excellent dispersibility and high film properties. This combination of polyurethane resin and vinyl chloride-vinyl acetate copolymer resin has been considered an essential ink ingredient for achieving good printability and the various physical properties required for lamination inks (adhesion to substrates, lamination strength, boil-retort suitability). For example, Patent Document 1 discloses a laminate ink composition for flexible packaging, the main components of which are a colorant, an organic solvent other than an aromatic organic solvent, and a binder resin containing, as essential components, a polypropylene glycol-containing polyurethane resin and a vinyl chloride-vinyl acetate copolymer resin having a hydroxyl group.

[0003] However, in response to the trend toward building a recycling-oriented society that reduces substances that may have adverse effects on humans or the environment, as exemplified by the Sustainable Development Goals, legal regulations surrounding food packaging are becoming stricter worldwide. In particular, in recent years, stricter regulations on packaging ingredients and their migration into food have been required. Furthermore, the movement toward eliminating plastics is accelerating, increasing demand for recyclable packaging. Therefore, in the development of gravure ink products, it has become necessary to design ink and packaging components using materials that are safe for humans and the environment. In particular, vinyl chloride-vinyl acetate copolymers are of concern as substances that hinder packaging recycling for the following reasons: (a) Chlorinated resins such as vinyl chloride can corrode equipment or piping by releasing hydrogen chloride during the thermal decomposition process of recycling, generating hydrochloric acid. (b) In thermal recycling, which reuses energy generated from waste incineration, the incineration of chlorinated resins can release environmental hormones such as dioxins. Therefore, the development of environmentally friendly inks, such as those that are chlorine-free, is required. For example, Patent Document 2 discloses a technology for an organic solvent-based gravure ink containing a pigment, an organic solvent, and a binder resin having a chlorine content of 5 mass% or less and containing a urethane resin (A) and a resin (B).

[0004] JP 2022-096163 A JP 2022-139294 A

[0005] The problem to be solved by the present invention is to provide a liquid ink resin composition for laminate films that is excellent in all of blocking resistance, adhesion to substrates, (extrusion) lamination strength, and two-component stability. The present invention also provides a laminate using the liquid ink composition for laminate films that satisfies the above properties, a recycled material using the laminate, a method for producing a recycled substrate using the laminate, and a method for producing recycled plastic pellets using the recycled substrate.

[0006] As a result of extensive research to solve the above problems, the inventors have completed the present invention by incorporating silica into a liquid ink composition for laminate films containing a binder resin and an organic solvent, and by focusing on the amine value of the solid content in the polyurethane resin contained in the binder resin.

[0007] That is, the present invention encompasses the following aspects: [1] A liquid ink composition for laminate films, comprising at least a binder resin, silica, and an organic solvent, wherein the binder resin comprises a polyurethane resin having an amine value of 0.1 mgKOH / g or more and 10 mgKOH / g or less of a solid content. [2] The liquid ink composition for laminate films according to [1], wherein the silica has a cumulative 50% particle diameter (D50) of a volume-based particle size distribution of 1 μm or more and 10 μm or less, and the cumulative 90% particle diameter (D90), the cumulative 50% particle diameter (D50), and the cumulative 10% particle diameter (D10) of the particle size distribution are expressed by the following formula (1): (D90-D10) / D50<2.0 (1) [3] The liquid ink composition for laminate films according to [1] or [2], wherein the content of the silica is 0.1% by mass or more and 7.0% by mass or less, based on the total solid content of the liquid ink composition for laminate films. [4] The liquid ink composition for laminate films according to any one of [1] to [3], wherein the binder resin further contains one or more resins selected from the group consisting of cellulose resins, polyester resins, acrylic resins, polyamide resins, rosin-modified maleic acid resins, polyvinyl butyral resins, vinyl chloride-vinyl acetate copolymers, chlorinated polypropylene, and ketone aldehyde resins. [5] The liquid ink composition for laminate films according to any one of [1] to [4], wherein the chlorine content of the binder resin is 5% by mass or less. [6] The liquid ink composition for laminate films according to any one of [1] to [5], wherein the liquid ink composition is for extrusion lamination. [7] A laminate having, in this order, a first base film, an ink layer, and a second base film, wherein the ink layer is a layer made of the liquid ink composition for laminate films described in any one of [1] to [5]. [8] The laminate described in [7], wherein the ink layer is a light-shielding printed layer and has at least a white ink layer containing titanium oxide and a non-white colored ink layer containing aluminum paste, carbon black, or an organic pigment, wherein the white ink layer and the colored ink layer are ink layers formed by solid printing. [9] The laminate described in [7] or [8], wherein the second base film includes a melt-extruded resin layer.

[10] The laminate according to any one of [7] to [9], which has an anchor coat layer between the ink layer and the second base film, the anchor coat layer being made of one or more resins selected from the group consisting of polyethyleneimine-based resins, polybutadiene-based resins, and polyisocyanate-based resins.

[11] The laminate according to any one of [7] to

[10] , which has both the first base film and the second base film being polyolefin resins.

[12] The laminate according to any one of [7] to

[11] , which has a detachable primer layer between the first base film and the ink layer, or between the ink layer and the second base film, or both.

[13] The laminate according to any one of [7] to

[12] , which has a detachable primer layer soluble in an alkaline solution.

[14] A recycled material using the laminate according to any one of [7] to

[13] .

[15] A method for producing a recycled substrate, comprising treating the laminate according to

[13] with an alkaline solution to dissolve the detachable primer layer, thereby removing the ink layer from the laminate.

[16] A method for producing recycled plastic pellets, comprising molding the recycled substrate obtained by the method for producing a recycled substrate according to

[15] using a molding machine.

[0008] The present invention can provide a liquid ink resin composition for laminate films that is excellent in all of blocking resistance, adhesion to substrates, (extrusion) lamination strength, and two-component stability. Furthermore, the present invention can provide a laminate using the liquid ink composition for laminate films that satisfies the above properties, a recycled material using the laminate, a method for producing a recycled substrate using the laminate, and a method for producing recycled plastic pellets using the recycled substrate.

[0009] 1 is a schematic diagram illustrating an overview of a laminate according to an embodiment of the present invention.

[0010] The following describes in detail an embodiment of the present invention (hereinafter referred to as the "present embodiment"); however, the present invention is not limited to the following description and can be implemented in various modifications within the scope of its gist.

[0011] [Definitions] Prior to a detailed description of the present invention, the definitions of the terms used in this specification will be explained. As used herein, "for laminate films" means use in a laminate-type structure in which a coating film (various layers or films) is further formed on an ink layer. As used herein, "liquid ink composition" refers to a liquid printing ink, such as gravure ink or flexographic ink, that is applied to a printing method using a printing plate, and preferably gravure ink or flexographic ink. Furthermore, "ink" used in the following description always refers to "printing ink." As used herein, "parts" always refer to "parts by mass," "total amount of ink" refers to the total amount of ink including all volatile components such as solvents, and "(ink or resin) solids (total amount)" refers to the total amount of only non-volatile components, excluding volatile components.

[0012] [Liquid ink composition for laminate film] The liquid ink composition for laminate film described in this specification (hereinafter also simply referred to as "liquid ink composition") contains at least a binder resin, silica, and an organic solvent. Details of each component will be described below.

[0013] (Binder Resin) In this specification, the term "binder resin" refers to a binder resin contained in an ink or ink composition. The binder resin may be dissolved in a solvent or may be in an emulsion state. The properties and characteristics of the polyurethane resin contained in the binder resin used in the present invention will be described below.

[0014] <Polyurethane Resin> In the present invention, polyurethane resin is a general term for a polymeric compound having a urethane bond (—NHCOO—). In the present invention, the polyurethane resin is a reaction product obtained by reacting (crosslinking / curing reaction) a polyester polyol with a polyisocyanate. The polyurethane resin may contain other polyols in addition to the polyester polyol and polyisocyanate, or may be a reaction product of a polyester polyol, a polyisocyanate, and another polyol. The polyurethane resin used in the liquid ink composition for laminate film of the present invention can be prepared by, for example, reacting polypropylene glycol and a polyol to be used in combination with a diisocyanate compound in a ratio such that the isocyanate groups are in excess to obtain a prepolymer having terminal isocyanate groups, and then curing the prepolymer in a suitable solvent, i.e., a solvent typically used for non-toluene gravure inks (e.g., ester solvents such as ethyl acetate, propyl acetate, and butyl acetate; ketone solvents such as acetone, methyl ethyl ketone, and methyl isobutyl ketone; alcohol solvents such as methanol, ethanol, isopropyl alcohol, and n-butanol; methyl The polyurethane resin can be produced by a two-stage process, which includes a step of reacting the prepolymer with a chain extender such as a diamine and / or a terminal blocking agent such as a monoamine in a hydrocarbon solvent such as hexane or hexane-1, hexane-2, hexane-3, hexane-4, hexane-5, hexane-6, hexane-7, hexane-8, hexane-9, hexane-10, hexane-11, hexane-12, hexane-13, hexane-14, hexane-15, hexane-16, hexane-17, hexane-18, hexane-19, hexane-20, hexane-21, hexane-22, hexane-23, hexane-24, hexane-25, hexane-26, hexane-27, hexane-28, hexane-29, hexane-30, hexane-31, hexane-32, hexane-33, hexane-34, hexane-35, hexane-36, hexane-37, hexane-38, hexane-39, hexane-40, hexane-41, hexane-42, hexane-43, hexane-44, hexane-45, hexane-46, hexane-47, hexane-48, hexane-49 ...If the equivalent ratio of isocyanate groups to amino groups is less than 1 / 1.3, the chain extender and / or the terminal blocking agent may remain unreacted, causing the polyurethane resin to yellow or emitting an odor after printing.

[0015] The chain extender may be any compound commonly used in the production of polyurethane resins, and examples thereof include diamines such as ethylenediamine, propylenediamine, hexamethylenediamine, diethylenetriamine, triethylenetetramine, isophoronediamine, and dicyclohexylmethane-4,4'-diamine; and amines having a hydroxyl group in the molecule such as 2-hydroxyethylethylenediamine, 2-hydroxyethylpropanyldiamine, 2-hydroxyethylpropylenediamine, di-2-hydroxyethylethylenediamine, di-2-hydroxyethylenediamine, di-2-hydroxyethylpropylenediamine, 2-hydroxypropylethylenediamine, di-2-hydroxypropylethylenediamine, and di-2-hydroxypropylethylenediamine. These chain extenders may be used alone or in combination of two or more.

[0016] The end-capping agent may be any compound intended for terminating the reaction, and a monovalent active hydrogen compound may also be used. Examples of such compounds include monoamines, such as mono- and di-alkylamines such as butylamine, octylamine, diethylamine, and di-n-butylamine, and alcohols such as ethanol and isopropyl alcohol. Furthermore, when it is particularly desired to introduce carboxyl groups into the polyurethane resin, amino acids such as glycine and L-alanine can be used as reaction terminators. These end-capping agents may be used alone or in combination of two or more. In the present invention, the amine value of the solid content of the polyurethane resin is 0.1 mgKOH / g or more and 10 mgKOH / g or less. The amine value of the solid content of the polyurethane resin is preferably 0.15 mgKOH / g or more, and more preferably 3 mgKOH / g or more. Furthermore, the amine value of the solid content is preferably 9 mgKOH / g or less, and more preferably 5 mgKOH / g or less. Among these, the amine value of the solids is preferably 0.15 mgKOH / g or more and 9 mgKOH / g or less, and particularly preferably 3 mgKOH / g or more and 5 mgKOH / g or less. By setting the amine value of the solids of the polyurethane resin to 0.1 mgKOH / g or more, it is possible to improve the adhesion between an ink layer made of a liquid ink composition for laminate films containing the polyurethane resin and an adjacent layer. Furthermore, by setting the amine value of the solids of the polyurethane resin to 10 mgKOH / g or less, it is possible to provide a liquid ink composition for laminate films containing the polyurethane resin with excellent two-component stability.

[0017] In the present invention, the weight-average molecular weight (Mw) of the polyurethane resin is preferably 8,000 or more, more preferably 15,000 or more. On the other hand, the weight-average molecular weight (Mw) of the polyurethane resin is preferably 100,000 or less, more preferably 80,000 or less. The upper and lower limits can be arbitrarily combined. Among these, the weight-average molecular weight (Mw) is preferably 8,000 or more and 100,000 or less, and particularly preferably 15,000 or more and 80,000 or less. A weight-average molecular weight (Mw) of 8,000 or more is preferable from the viewpoint of excellent blocking resistance of the resulting ink composition, strength and oil resistance of the printed film, and adhesion. On the other hand, a weight-average molecular weight (Mw) of 100,000 or less results in an appropriate viscosity of the resulting liquid ink composition, excellent gloss of the printed film, and is also preferable from the viewpoint of blocking resistance and laminate strength. In the present invention, the urethane bond concentration of the polyurethane resin is preferably 0.30 mmol / g or more, more preferably 0.40 mmol / g or more. On the other hand, the urethane bond concentration of the polyurethane resin is preferably 2.0 mmol / g or less, more preferably 1.8 mmol / g or less. Among these, the urethane bond concentration is preferably 0.30 mmol / g or more and 2.0 mmol / g or less, and particularly preferably 0.40 mmol / g or more and 1.8 mmol / g or less. A urethane bond concentration of 0.30 mmol / g or more is preferred from the viewpoint of polyethylene extrusion lamination strength when printed on OPP film. On the other hand, a urethane bond concentration of 2.0 mmol / g or less is preferred from the viewpoints of polyurethane resin raw material cost, ink viscosity, and flexibility of the ink coating film on the film (adaptability to film deformation). In the present invention, the urea bond concentration of the polyurethane resin is preferably 0.30 mmol / g or more, more preferably 0.50 mmol / g or more. On the other hand, the urea bond concentration of the polyurethane resin is preferably 2.0 mmol / g or less, and more preferably 1.5 mmol / g or less.Among these, the urea bond concentration is preferably 0.30 mmol / g or more and 2.0 mmol / g or less, and particularly preferably 0.30 mmol / g or more and 1.5 mmol / g or less. A urea bond concentration of 0.50 mmol / g or more is preferred from the viewpoint of improving the durability of the final liquid ink composition. On the other hand, a urea bond concentration of 2.0 mmol / g or less is preferred from the viewpoint of solubility in organic solvents.

[0018] The urethane bond concentration can be calculated by the following formula (2): Urethane bond concentration = {(W １ ×OH １ +W ２ ×OH ２ +...+W ｉ ×OH ｉ ) × 1000} / (56100 × S) Equation (2) In equation (2), W is as follows. １ OH: Weight of polyol 1 １ OH: hydroxyl value of polyol 1 W2: weight of polyol 2 ２ W: hydroxyl value of polyol 2 ｉ OH: weight of polyol i ｉ : hydroxyl value of polyol i S: weight of urethane resin solid content

[0019] The urea binding concentration can be calculated by the following formula (3): Urea binding concentration = {(X １ / M １ +X ２ / M ２ +...+X ｉ / M ｉ ) × 2 - (W １ ×OH １ +W ２ ×OH ２ +...+W ｉ ×OH ｉ ) / 56100}×1000 / S Formula (2) In formula (3), the symbols are as follows: X １ : Weight of diisocyanate compound 1 M １ : Molecular weight of diisocyanate compound 1 X ２ : Weight of diisocyanate compound 2 M ２ : Molecular weight of diisocyanate compound 2 Xｉ : Weight of diisocyanate compound i M ｉ W: molecular weight of diisocyanate compound i １ OH: Weight of polyol 1 １ W: hydroxyl value of polyol 1 ２ OH: weight of polyol 2 ２ W: hydroxyl value of polyol 2 ｉ OH: weight of polyol i ｉ : hydroxyl value of polyol i S: weight of urethane resin solid content

[0020] The content of the polyurethane resin used in the liquid ink composition for laminate film of the present invention, for example, in a resin solution with a nonvolatile content of 30%, is preferably 4% by mass or more relative to the total weight of the ink to ensure sufficient adhesion of the ink to the substrate, and 50% by mass or less to ensure adequate ink viscosity and efficient ink production and printing. A range of 4% to 50% by mass is preferred, with a range of 6% to 40% by mass being even more preferred. The hydroxyl value of the polyurethane resin is preferably 10 mgKOH / g or less, more preferably 3 mgKOH / g or less, and even more preferably 0 mgKOH / g. A hydroxyl value of 10 mgKOH / g or less can suppress deterioration of the ink layer's substrate adhesion and water-rubbing resistance, and improve two-component stability. The acid value can be determined by the number of mg of KOH required when titrating the COOH groups contained in 1 g of urethane resin using the potassium hydroxide method, and the weight-average molecular weight can be measured by gel permeation chromatography (GPC). The hydroxyl value can be measured in accordance with the method described in JIS K0070.

[0021] The polyurethane resin according to the present invention is a compound made from polyisocyanate, polyester polyol, and other polyols as reaction raw materials. Each component of the reaction raw materials will be described in detail below.

[0022] The polyisocyanate may be any compound having two or more isocyanate groups, and is preferably a diisocyanate compound, such as various known aromatic diisocyanates, aliphatic diisocyanates, and alicyclic diisocyanates that are commonly used in the production of polyurethane resins. For example, 1,5-naphthylene diisocyanate, 4,4'-diphenylmethane diisocyanate, 4,4'-diphenyldimethylmethane diisocyanate, 4,4'-dibenzyl isocyanate, dialkyldiphenylmethane diisocyanate, tetraalkyldiphenylmethane diisocyanate, 1,3-phenylene diisocyanate, 1,4-phenylene diisocyanate, tolylene diisocyanate, butane-1,4-diisocyanate, hexamethylene diisocyanate, isopropylene diisocyanate, methylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, lysine diisocyanate, cyclohexane-1 Examples of suitable diisocyanate compounds include 4,4-diisocyanate, xylylene diisocyanate, isophorone diisocyanate, dimeryl diisocyanate, dicyclohexylmethane-4,4'-diisocyanate, 1,3-bis(isocyanatomethyl)cyclohexane, methylcyclohexane diisocyanate, norbornane diisocyanate, m-tetramethylxylylene diisocyanate, 4,4-diphenylmethane diisocyanate, tolylene diisocyanate, bis-chloromethyl-diphenylmethane-diisocyanate, 2,6-diisocyanato-benzyl chloride, and dimer diisocyanate in which the carboxyl groups of dimer acid are converted to isocyanate groups. These diisocyanate compounds can be used alone or in combination of two or more.

[0023] <Polyester Polyol> The polyester polyol is preferably a polyester polyol obtained by dehydration condensation or polymerization of a low-molecular-weight polyol and a polycarboxylic acid or an anhydride thereof. The polyester polyol can further increase laminate strength by introducing an ester group to increase cohesive energy.

[0024] As the low-molecular-weight polyol, various known compounds having two or more hydroxyl groups that are generally used in the production of polyester polyols can be used, and one or more of them may be used in combination. Specific examples include glycols such as ethylene glycol, propylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol, tripropylene glycol, 1,4-cyclohexanediol, and 1,4-cyclohexanedimethanol; 2-methyl-1,5-pentanediol, 3-methyl-1,5-pentanediol, 1,2-butanediol, 1,3-butanediol, 2-butyl-2-ethyl-1,3- Glycols having a branched structure such as propanediol, 1,2-propanediol, 2-methyl-1,3-propanediol, neopentyl glycol, 2-isopropyl-1,4-butanediol, 2,4-dimethyl-1,5-pentanediol, 2,4-diethyl-1,5-pentanediol, 2-ethyl-1,3-hexanediol, 2-ethyl-1,6-hexanediol, 3,5-heptanediol, and 2-methyl-1,8-octanediol; glycerin, trimethylolpropane, trimethylolethane, pentaerythritol, and sorbitol can be used.

[0025] The polycarboxylic acid or anhydride thereof may be any of various known polycarboxylic acids commonly used in the production of polyester polyols, and one or more of these may be used in combination. Specific examples include polycarboxylic acids having 6 or less carbon atoms and two or more carboxyl groups, such as oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, fumaric acid, maleic acid, and the anhydrides of these acids; aromatic dicarboxylic acids, such as phthalic acid, isophthalic acid, terephthalic acid, and the anhydrides of these acids; aliphatic dicarboxylic acids, such as pimelic acid, suberic acid, azelaic acid, sebacic acid, and dimer acid; tricarboxylic acids, such as trimellitic acid and the anhydrides thereof; benzenetetracarboxylic acid, benzenepentacarboxylic acid, benzenehexacarboxylic acid, and the anhydrides of these acids.

[0026] The polyester polyol may be any of various known polyester polyols generally used in the production of polyurethane resins, such as polyester polyols obtained by ring-opening polymerization of cyclic ester compounds, for example, lactones such as polycaprolactone, polyvalerolactone, and poly(β-methyl-γ-valerolactone), and one or more of these may be used in combination.

[0027] The number average molecular weight of the polyester polyol is preferably in the range of 500 to 8,000, more preferably in the range of 800 to 7,000, and even more preferably in the range of 900 to 6,000.

[0028] <Other Polyols> Examples of the other polyols include polyether polyols and polyols used in combination.

[0029] <<Polyether Polyol>> The polyether polyol may be any of various known polyether polyols commonly used in the production of polyurethane resins, and one or more of these may be used in combination. Examples include polyether polyols of polymers or copolymers of methylene oxide, ethylene oxide, propylene oxide, tetrahydrofuran, and the like. Specifically, known, general-purpose polyether polyols such as polyethylene glycol, polypropylene glycol, and polytetramethylene glycol may be used. The inclusion of a polyether polyol significantly improves adhesion, particularly to high-performance barrier films, resulting in excellent blocking resistance and laminate strength. The polyether polyol preferably has a number-average molecular weight of 100 to 3,500. The polyether polyol is preferably contained as a residue in an amount of 1 to 40% by mass relative to the polyurethane resin.

[0030] <<Polyol Used in Combination>> As the polyol used in combination, various known polyols generally used in the production of polyurethane resins can be used, and one or more of them may be used in combination. Examples of the polyol used in combination include saturated polyols such as ethylene glycol, 1,2-propanediol, 1,3-propanediol, 2-methyl-1,3propanediol, 2-ethyl-2-butyl-1,3propanediol, 1,3-butanediol, 1,4-butanediol, neopentyl glycol, pentanediol, 3-methyl-1,5pentanediol, hexanediol, octanediol, 1,4-butynediol, 1,4-butylenediol, diethylene glycol, triethylene glycol, dipropylene glycol, glycerin, trimethylolpropane, trimethylolethane, 1,2,6-hexanetriol, 1,2,4-butanetriol, sorbitol, and pentaerythritol. Examples of suitable polyols include saturated or unsaturated low-molecular-weight polyols (1); polycarbonate polyols (2) obtained by reacting the above-mentioned low-molecular-weight polyols with, for example, dimethyl carbonate, diphenyl carbonate, ethylene carbonate, phosgene, etc.; polybutadiene glycols (3); glycols (4) obtained by adding ethylene oxide or propylene oxide to bisphenol A; and acrylic polyols (4) obtained by copolymerizing, in one molecule, one or more hydroxyethyl groups, hydroxypropyl acrylate, hydroxybutyl acrylate, etc., or their corresponding methacrylic acid derivatives, with, for example, acrylic acid, methacrylic acid, or an ester thereof.

[0031] <Other Resins> The binder resin of the present invention may further contain various resins other than the polyurethane resin, such as one or more resins selected from the group consisting of cellulose resins, polyester resins, acrylic resins, polyamide resins, rosin-modified maleic acid resins, polyvinyl butyral resins, vinyl chloride-vinyl acetate copolymers, chlorinated polypropylene, and ketone aldehyde resins. This makes it possible to form an ink layer that is superior in blocking resistance, adhesion, lamination suitability, scratch resistance, pigment dispersibility, fluidity, and storage (aging) stability.

[0032] In the liquid ink composition for laminate film of this embodiment, the proportion of the polyurethane resin component (solid content) relative to the total solid content of the binder resin (solid content) is preferably 30% by mass or more and 100% by mass or less, more preferably 40% by mass or more and 90% by mass or less, and even more preferably 50% by mass or more and 80% by mass or less. By making the proportion of the polyurethane resin component (solid content) 30% by mass or more, good extrusion lamination strength can be exhibited when printed on OPP film or the like, which is preferable.

[0033] —Chlorine Content— Furthermore, the chlorine content of the total resin solids of the binder resin in the present invention is preferably 5% by mass or less, more preferably 1% by mass or less, and even more preferably 0% by mass. Although the lower limit of the chlorine content can be said to be 0% by mass, the chlorine content may exceed 0% by mass because unavoidable amounts of chlorine may be present during the binder resin production process. By keeping the chlorine content in the binder resin at 5% by mass or less, the amount of chlorine gas emitted during the production of recycled pellets from the resin can be reduced, which is preferable from the perspective of equipment maintenance. From this perspective, liquid ink compositions using the binder resin in the present invention are particularly suitable for use as liquid ink compositions for extrusion lamination, in which the binder resin is exposed to high temperatures during recycling.

[0034] The chlorine content can be calculated from the chlorine content in the total resin solid content in the liquid ink composition using the following formula: (chlorine content contained in the total resin solid content in the liquid ink composition) = (chlorine contained in the total resin solid content in the liquid ink composition) / (mass of the total resin solid content in the liquid ink composition)

[0035] (Silica) In this specification, "silica" refers to silicon dioxide (SiO ２"Silica" refers to a general term for substances composed of silicon dioxide or silicon dioxide. Silica may be crystalline or amorphous. It may also be contained in natural minerals or may be added to dioctahedral smectite. Crystalline silica refers to a solid substance having a crystalline structure (atoms, ions, or molecules that constitute a crystal are arranged with three-dimensional periodicity to form a spatial lattice). Amorphous silica refers to a solid substance in which atoms (or molecules) are aggregated without forming crystals with a regular spatial arrangement. Specific examples of "silica" include silicon dioxide, epoxy-modified silicone, amino-modified silicone, and polyester-modified silicone. The shape of "silica" is not particularly limited, but particulate silica (hereinafter also referred to as silica particles) is preferred.

[0036] - Particle Size Distribution - Here, in the present invention, the preferred particle size distribution of silica is determined using a volume-based particle size distribution measured with a laser diffraction particle size distribution analyzer. The cumulative 90% particle diameter (D90) of the volume-based particle size distribution of silica is preferably 3 μm or more, more preferably 4 μm or more, and even more preferably 5 μm or more. The cumulative 90% particle diameter (D90) is preferably 50 μm or less, more preferably 40 μm or less, and even more preferably 30 μm or less. Similarly, the cumulative 50% particle diameter (D50) of the volume-based particle size distribution of silica is preferably 1 μm or more, more preferably 2 μm or more, and even more preferably 3 μm or more. The cumulative 50% particle diameter (D50) is preferably 30 μm or less, more preferably 20 μm or less, and even more preferably 10 μm or less. Furthermore, the cumulative 10% particle diameter (D10) of the volume-based particle size distribution of the silica is preferably 1 μm or more, more preferably 1.5 μm or more, and even more preferably 2 μm or more. The cumulative 10% particle diameter (D10) of the volume-based particle size distribution of the silica is preferably 10 μm or less, more preferably 5 μm or less, and even more preferably 4 μm or less. The cumulative 50% particle diameter (D50) of the volume-based particle size distribution of the silica is preferably 1 μm or more and 10 μm or less, and the index (D90-D10) / D50, calculated using the cumulative 90% particle diameter (D90), cumulative 50% particle diameter (D50), and cumulative 10% particle diameter (D10) of the particle size distribution, is preferably less than 2.0 (i.e., (D90-D10) / D50<2.0), more preferably less than 1.5, and even more preferably less than 1.0. Since the thickness of the ink layer on a laminate film is generally around 1 μm, a liquid ink composition for laminate films with excellent blocking resistance can be obtained by using silica particles with a size equal to or greater than this thickness. The index (D90 - D10) / D50 represents the uniformity of size per particle diameter, and the smaller the value, the less variation there is in the particle diameter of the powder in the measured system.When such particulate substances are incorporated into the liquid ink composition, the surface of the ink layer containing the liquid ink composition becomes rough, which results in an increase in the adhesive area with the extruded melt layer or the like that comes into contact with the ink layer, thereby improving strength, which is preferable.

[0037] (Organic Solvent) Examples of organic solvents that serve as a solvent for the binder resin include acetate esters such as ethyl acetate, normal propyl acetate, and butyl acetate; alcohols such as methanol, ethanol, n- and isopropanol; ketones such as acetone and methyl ethyl ketone; polyalkylene glycols such as ethylene glycol, diethylene glycol, and propylene glycol; alkyl ethers of polyalkylene glycol; and N-methyl-2-pyrrolidone. Since film-forming materials widely used on plastic substrates require consideration for the health of workers and the environment, it is preferable to use toluene-free, ketone-free, and particularly methyl ethyl ketone (MEK)-free organic solvents. Ethyl acetate, normal propyl acetate, and isopropyl alcohol are preferred. Furthermore, in order to improve the transferability of the ink to the substrate and prevent so-called plate clogging, it is preferable to use a glycol ether-based solvent with a slow evaporation rate, such as propylene glycol monomethyl ether. When dispersing the binder resin and pigment in the organic solvent, a machine such as a homogenizer can be used as needed.

[0038] The liquid ink composition of the present invention may contain a colorant. Examples of the colorant (D) include organic and inorganic pigments and dyes commonly used in inks, paints, and recording materials. Examples of organic pigments include azo-based, phthalocyanine-based, anthraquinone-based, perylene-based, perinone-based, quinacridone-based, thioindigo-based, dioxazine-based, isoindolinone-based, quinophthalone-based, azomethine azo-based, dicetpyrrolopyrrole-based, and isoindoline-based pigments. It is preferable to use copper phthalocyanine for indigo inks and C.I. Pigment No. 83 for transparent yellow inks in terms of cost and lightfastness.

[0039] Examples of inorganic pigments include carbon black, titanium oxide, zinc oxide, zinc sulfide, barium sulfate, calcium carbonate, chromium oxide, silica, red iron oxide, aluminum, and mica. Furthermore, a lustrous pigment (Metashine; Nippon Sheet Glass Co., Ltd.) made of glass flakes or aggregate flakes coated with a metal or metal oxide can be used. From the standpoints of cost and coloring strength, titanium oxide is preferred for white ink, carbon black for black ink, aluminum for gold and silver ink, and mica for pearl ink. Aluminum is available in powder or paste form, but paste form is preferred for ease of handling and safety. Whether leafing or non-leafing is used is determined based on brightness and density. The colorant is preferably included in an amount sufficient to ensure the density and coloring strength of the ink, i.e., 1% to 50% by weight of the total weight of the ink. Furthermore, colorants can be used alone or in combination of two or more types.

[0040] (Other Additives) The liquid ink composition of the present invention may contain various additives, such as film-forming aids, crosslinking agents, curing accelerators, plasticizers, antistatic agents, waxes, light stabilizers, flow modifiers, dyes, leveling agents, rheology control agents, UV absorbers, antioxidants, photocatalytic compounds, inorganic pigments, organic pigments, and extender pigments, as needed. Furthermore, to stably disperse pigments in organic solvents, the resins mentioned above can be used alone, but a dispersant can also be used in combination to further stably disperse the pigment. Examples of dispersants that can be used include anionic, nonionic, cationic, and amphoteric surfactants. Examples include comb-structured polymers in which polyester is added to polyethyleneimine, and alkylamine derivatives of α-olefin maleic acid polymers. Specific examples include the Solsperse series (Lubrizol), the Ajisper series (Ajinomoto), and the Homogenol series (Kao). The BYK series (BYK-Chemie) and the EFKA series (EFKA) can also be used as appropriate. The dispersant is preferably contained in the ink in an amount of 0.05% by mass or more relative to the total weight of the ink from the viewpoint of storage stability of the ink, and 5% by mass or less from the viewpoint of lamination suitability, and more preferably in the range of 0.1% by mass or more and 2% by mass or less. The presence of a dispersant improves the sedimentation and stability over time of the pigment, and also improves the two-component stability when a curing agent is used in combination with the ink, for example.

[0041] Among the additives, emulsifiers and leveling agents may cause a decrease in the durability of the resulting film, etc., so when high durability is required for the film, etc., it is preferable to use them in a range of 5 mass % or less based on the total amount of the liquid ink composition.

[0042] The components described above can be mixed in any desired ratio. In the liquid ink composition for laminate films of this embodiment, the content of the polyurethane resin component (solid content) is preferably 5% by mass or more, more preferably 10% by mass or more, and even more preferably 15% by mass or more, based on the total solid content of the liquid ink composition. It is also preferably 95% by mass or less, more preferably 90% by mass or less, and even more preferably 80% by mass or less. Among these, the content of the polyurethane resin component (solid content) is preferably 5% by mass or more and 95% by mass or less, more preferably 10% by mass or more and 90% by mass or less, and particularly preferably 15% by mass or more and 80% by mass or less. By setting the content of the polyurethane resin component (solid content) to 5% by mass or more, good polyethylene extrusion lamination strength is exhibited when printed on a laminate film, and particularly favorable strength is exhibited on OPP films.

[0043] Furthermore, in the liquid ink composition for laminate film of this embodiment, the content of the binder resin (solid content) is preferably 5% by mass or more, more preferably 10% by mass or more, and even more preferably 15% by mass or more, based on the total solid content of the liquid ink composition. It is also preferably 95% by mass or less, more preferably 90% by mass or less, and even more preferably 80% by mass or less. Among these, the content of the binder resin (solid content) is preferably 5% by mass or more and 95% by mass or less, more preferably 10% by mass or more and 90% by mass or less, and particularly preferably 15% by mass or more and 80% by mass or less. By setting the content of the binder resin (solid content) to 5% by mass or more, good pigment dispersion stability and coating film properties are exhibited. On the other hand, by setting the content of the binder resin (solid content) to 80% by mass or less, good print color density is exhibited.

[0044] In the liquid ink composition for laminate films of this embodiment, the silica content is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, and even more preferably 1.0% by mass or more, based on the total solids content of the liquid ink composition for laminate films. It is also preferably 7.0% by mass or less, more preferably 6.5% by mass or less, and even more preferably 6.0% by mass or less. Among these, the silica content is preferably 0.1% by mass or more to 7.0% by mass or less, more preferably 0.5% by mass or more to 6.5% by mass or less, and particularly preferably 1.0% by mass or more to 6.0% by mass or less. Adding a specific silica within the above-mentioned range increases the roughness of the ink surface layer, increasing the contact area with the extruded molten layer and, as a result, improving extrusion laminate strength. That is, if the content exceeds 7.0% by mass, laminate strength tends to decrease, while if the content is below 0.1% by mass, the anti-blocking effect decreases. In addition, by having a moderate surface roughness, it is possible to suppress poor appearance after dry lamination and non-solvent lamination, so it is possible to achieve both extrusion lamination strength and the appearance of dry and non-solvent lamination.

[0045] (Production Method) The liquid ink composition for laminate film of this embodiment can be produced by dissolving and / or dispersing a resin, a colorant, etc. in a solvent. Specifically, a pigment dispersion is produced by dispersing a pigment, etc. in an organic solvent with a resin, and other compounds, etc. are blended with the obtained pigment dispersion as needed to produce the ink.

[0046] (Dispersion Method) The particle size distribution of the pigment in the pigment dispersion can be adjusted by appropriately adjusting the size of the grinding media of the disperser, the packing ratio of the grinding media, the dispersion treatment time, the discharge speed of the pigment dispersion, the viscosity of the pigment dispersion, etc. As the disperser, commonly used dispersers such as a roller mill, ball mill, pebble mill, attritor, sand mill, etc. can be used. If air bubbles or unexpectedly large particles are contained in the ink, they are preferably removed by filtration or the like, as they will deteriorate the quality of the printed matter. As the filter, a conventionally known filter can be used.

[0047] The liquid ink composition for laminate films described above is excellent in all of the properties of blocking resistance, adhesion to substrates, and two-component stability. Furthermore, when this liquid ink composition for laminate films is used in extrusion lamination, it provides excellent extrusion lamination strength, making the liquid ink composition for laminate films of the present invention particularly suitable for use in extrusion lamination.

[0048] [Laminate] A laminate formed using the liquid ink composition will be described below with reference to Figure 1. The laminate 100 according to the present invention comprises, in this order, a first substrate film 10, an ink layer 30 composed of the liquid ink composition for laminate films described above, and a second substrate film 50. That is, the laminate 100 of the present invention is intended to be a laminate-type laminate in which a substrate (hereinafter referred to as the first substrate film 10) is disposed on the side of the ink layer 30 opposite to the side on which the substrate (hereinafter referred to as the second substrate film 50) is disposed, and the first substrate film 10, the ink layer 30, and the second substrate film 50 are laminated together. The laminate 100 according to the present invention may also comprise an anchor coat layer 70 between the ink layer 30 and the second substrate film 50. Furthermore, the laminate 100 according to the present invention may have a detachable primer layer 90 (the detachable primer layer on the first substrate film side is referred to as a first detachable primer layer 91, and the detachable primer layer on the second substrate film side is referred to as a second detachable primer layer 92) on either or both of the space between the first substrate film 10 and the ink layer 30 and the space between the ink layer 30 and the second substrate film 50. Details of each layer or film constituting the laminate will be described below. Note that, to avoid complication, reference numerals will be omitted.

[0049] (First base film) Examples of the first base film (hereinafter also simply referred to as "base material") include an OPP film (a polypropylene film, for example, a biaxially oriented polypropylene film), a PET film (a polyethylene terephthalate film, for example, a biaxially oriented polyethylene terephthalate film), and a nylon film. The first base film may be coated for the purposes of improving gas barrier properties and ink receptivity when an ink layer is provided. Examples of commercially available coated first base films include a K-OPP film and a K-PET film.

[0050] (Ink Layer) The ink layer is an ink layer containing a liquid ink composition for laminate films, and refers to, for example, an ink layer colored with a printing ink. Examples of the ink layer include an ink layer formed with a printing ink containing a colored pigment or a white pigment as a colorant. The printing method for the ink layer is not particularly limited, and the ink layer can be formed by various printing methods such as gravure printing, flexographic printing, offset printing, inkjet printing, and screen printing. The printing ink can be an ink appropriate for the various printing methods, and may be a solvent-based ink or a water-based ink. UV-curable or EB-curable inks may also be used.

[0051] Furthermore, the ink layer is preferably a light-shielding printed layer. The light-shielding printed layer preferably has at least a white ink layer containing titanium oxide and a non-white colored ink layer containing aluminum paste, carbon black, or an organic pigment, and the white ink layer and the colored ink layer are preferably ink layers formed by solid printing. The ink layer as a whole preferably has a light transmittance of 10% or less, more preferably 5% or less, for light rays of 450 nm or more and 550 nm or less. This is because light in this wavelength range (especially 510 nm) promotes the oxidation of oil and deteriorates the laminate. From the same perspective, it is preferable that each ink layer contains a UV-blocking agent. The order of the ink layers in the light-shielding laminate is not particularly limited and can be laminated in any order. They may be formed of any two layers, such as substrate / white / black, substrate / black / white, or substrate / white / red, or they may be formed of three or more layers, such as substrate / white / white / silver, or substrate / white / silver / white, etc. The multi-layer coating of substrate / white / white, etc., can be formed by, for example, gravure printing or flexographic printing. Furthermore, it is preferable to form ink layers by solid printing, as this is superior in covering the entire packaging material. The amount of ink applied also affects the light-shielding properties, so the amount of ink applied for each layer should be 0.5 g / m. 2 5.0g / m or more 2 It is preferable to do the following:

[0052] (Removable Primer Layer) The removable primer layer (hereinafter also referred to simply as "primer layer") is a layer that is provided as a layer in contact with the substrate, ink layer, or anchor coat layer, thereby facilitating peeling of the ink layer or separation of the laminate film into single-layer films. Providing a primer layer on a laminate can improve the recyclability of the laminate and the quality of the recycled plastic. The removable primer layer is preferably provided between the first substrate film and the ink layer, or between the ink layer and the second substrate film, or both. The removable primer layer is preferably soluble in an alkaline solution. In this case, known materials can be used for the primer layer, and there are no particular restrictions on the layer as long as it is a layer that can be removed from the substrate by dissolving or swelling in an alkaline solution. However, because it is easily dissolved or hydrolyzed in an alkaline solution, it is preferable for the layer to contain a compound having an acidic group, a water-soluble resin, or an inorganic material that is soluble by treatment with an alkaline solution. Details of each material that can constitute the removable primer layer are described below.

[0053] <Compound Having an Acidic Group> The compound having an acidic group can be a resin having an acidic group or a low-molecular-weight compound having an acidic group. Examples of the resin having an acidic group include resins having an acid value such as urethane resins, cellulose-based resins, ketone resins, polyester resins, rosin-modified maleic acid resins, rosin-modified fumaric acid resins, chlorinated polypropylene resins, ethylene-vinyl acetate copolymer resins, vinyl acetate resins, alkyd resins, polyvinyl chloride resins, cyclized rubber, chlorinated rubber, butyral resins, and petroleum resins, as well as radical copolymer resins such as styrene-(meth)acrylic resins, styrene-maleic (anhydride) resins, and terpene-maleic (anhydride) resins copolymerized with polymerizable monomers having an acidic group, such as polymerizable monomers having a carboxyl group (e.g., itaconic acid, maleic acid, fumaric acid, cinnamic acid, or acid anhydrides thereof), polymerizable monomers having a sulfonic acid group (e.g., sulfonated styrene), and polymerizable monomers having a sulfonamide group (e.g., vinylbenzenesulfonamide), and acid-modified polyolefin resins. These resins can be used singly or in combination. The resin having an acidic group is more preferably a urethane resin having an acidic group, an acrylic resin having an acidic group, a resin having an acid value such as a rosin-modified maleic acid resin or a rosin-modified fumaric acid resin, or a styrene-maleic anhydride resin.

[0054] The acid value of the resin having an acidic group is not particularly limited, but is preferably 150 mgKOH / g or more, and more preferably 150 mgKOH / g or more and 500 mgKOH / g or less.

[0055] The molecular weight of the resin having an acidic group is not particularly limited, but it is preferable that the weight average molecular weight (Mw) is in the range of 500 or more and 20,000 or less.

[0056] The low molecular weight compound having an acidic group can be, for example, an organic acid. Preferred examples of the low molecular weight compound having an acidic group include saturated fatty acids, unsaturated fatty acids, hydroxy acids, aromatic carboxylic acids, dicarboxylic acids, tricarboxylic acids, oxocarboxylic acids, and carboxylic acid derivatives, and these can be used singly or in combination.

[0057] The acid value of the compound having an acidic group is not particularly limited, but is preferably 1 mgKOH / g or more, more preferably 3 mgKOH / g or more, more preferably 5 mgKOH / g or more, more preferably 10 mgKOH / g or more, more preferably 20 mgKOH / g or more, more preferably 30 mgKOH / g or more, more preferably 40 mgKOH / g or more, and more preferably 50 mgKOH / g or more. The acid value is preferably 900 mgKOH / g or less, more preferably 850 mgKOH / g or less, more preferably 800 mgKOH / g or less, more preferably 750 mgKOH / g or less, more preferably 700 mgKOH / g or less, more preferably 650 mgKOH / g or less, more preferably 600 mgKOH / g or less, and more preferably 550 mgKOH / g or less. Among these, the acid value is preferably 1 mgKOH / g or more and 900 mgKOH / g or less, more preferably 3 mgKOH / g or more and 850 mgKOH / g or less, more preferably 5 mgKOH / g or more and 800 mgKOH / g or less, more preferably 10 mgKOH / g or more and 750 mgKOH / g or less, more preferably 20 mgKOH / g or more and 700 mgKOH / g or less, more preferably 30 mgKOH / g or more and 650 mgKOH / g or less, more preferably 40 mgKOH / g or more and 600 mgKOH / g or less, and more preferably 50 mgKOH / g or more and 550 mgKOH / g or less. By setting it within the above range, both alkaline solution releasability and adhesion to the substrate can be achieved.

[0058] <Water-soluble resin> The water-soluble resin may be any resin that swells or dissolves in water and can be released from the plastic substrate. Such resins can be selected from known resins as long as they do not impair water solubility. Examples include water-soluble polyester resins, water-soluble polyamide resins, water-soluble polyimide resins, water-soluble acrylic resins, water-soluble polyurethane resins, water-soluble polyallylamine resins, water-soluble phenolic resins, water-soluble epoxy resins, water-soluble phenoxy resins, water-soluble urea resins, water-soluble melamine resins, polyvinyl alcohol resins, and modified products of these resins. These resins can be used alone or in combination of two or more. Among them, polyvinyl alcohol (PVA) resins are preferred from the viewpoints of availability and release properties. The polyvinyl alcohol-containing primer layer is preferably a resin layer containing at least 25% by mass of polyvinyl alcohol.

[0059] <Inorganic materials that exhibit solubility upon treatment with an alkaline solution> Examples of inorganic materials that exhibit solubility upon treatment with an alkaline solution include inorganic oxides such as alumina, silica, zirconia, magnesia, ceria, yttria, zinc oxide, and iron oxide; inorganic nitrides such as silicon nitride, titanium nitride, and boron nitride; ceramics such as silicon carbide, calcium carbonate, magnesium sulfate, aluminum sulfate, aluminum hydroxide, aluminum oxide hydroxide, potassium titanate, talc, kaolinite, dickite, nacrite, halloysite, pyrophyllite, montmorillonite, sericite, mica, amesite, bentonite, asbestos, zeolite, calcium silicate, magnesium silicate, diatomaceous earth, and silica sand; metals such as aluminum; and glass fibers. These inorganic materials may be used alone or in combination. These inorganic materials exhibit solubility in an alkaline solution, and therefore contribute to the release function of the primer layer.

[0060] The inorganic material may be contained in a layer containing particles containing the inorganic material and a binder resin, or in a vapor-deposited layer of at least one type selected from the group consisting of the inorganic materials. When a binder resin is used as a layer containing the binder resin, the binder resin is not particularly limited, but examples include cellulose-based resins, urethane resins, polyamide resins, vinyl chloride-vinyl acetate copolymer resins, ketone resins, polyester resins, (meth)acrylic resins, rosin-modified maleic acid resins, rosin-modified fumaric acid resins, chlorinated polypropylene resins, ethylene-vinyl acetate copolymer resins, vinyl acetate resins, alkyd resins, polyvinyl chloride resins, cyclized rubbers, chlorinated rubbers, butyral resins, and petroleum resins, and these can be used in combination. Urethane resins, (meth)acrylic resins, rosin-based resins, and modified versions thereof are often used in combination. Furthermore, the mass ratio of the binder resin to the metal particles (binder resin / metal particles) is preferably 90 / 10 to 20 / 80. In the case of a vapor deposition layer, it is preferably made of at least one material selected from alumina, silica, and aluminum, and can be formed by a conventionally known method, with no particular limitations on its composition or formation method.

[0061] The primer layer of the present invention is obtained by applying a primer layer-forming composition containing the above-mentioned resin, as well as solvents such as organic solvents and aqueous solvents, and auxiliary agents, to a substrate and drying the composition. Depending on the configuration of the laminate, the primer layer may be provided on an ink layer or an adhesive layer. The primer layer coating amount is approximately 0.1 μm to 5 μm (dry thickness); however, a thickness less than 0.1 μm makes it difficult to apply uniformly, and a thickness exceeding 5 μm is uneconomical and therefore impractical. Conventional coating methods, such as gravure, letterpress, flexography, roll coater, reverse coater, and spray method, are used for coating. The formation of the primer layer and printing thereon may be performed continuously (in-line), or the formation of the primer layer and printing may be performed separately.

[0062] (Anchor Coat Layer) For the anchor coat layer, a known adhesive for film lamination can be used as appropriate. When laminating by extrusion lamination, a known anchor coat agent for extrusion lamination can be used as an adhesive auxiliary. When a material having gas barrier properties is used for these adhesives or anchor coat agents, a laminate with particularly excellent barrier properties can be obtained. An adhesive with excellent gas barrier properties is particularly preferably 3 g / m ２ The oxygen barrier property of the cured coating film of the adhesive applied at (solid content) is 300 cc / m ２ / day / atm or less, or water vapor barrier property of 120 g / m ２ / day refers to a coating that satisfies at least one of the following conditions. Commercially available products include the "PASLIM" series, such as PASLIM VM001 and PASLIM J350X, manufactured by DIC Corporation, and "MAXIEVE" manufactured by Mitsubishi Gas Chemical Company, Inc. The anchor coat layer is preferably provided between the ink layer and the second base film, and the anchor coat layer is preferably made of one or more resins selected from the group consisting of polyethyleneimine-based resins, polybutadiene-based resins, and polyisocyanate-based resins.

[0063] (Second substrate film) The second substrate film may be made of the same material as the first substrate film, and preferably includes a melt-extruded resin layer. Here, the term "melt-extruded resin layer" refers to a resin layer formed by laminating a molten resin onto the surface of an ink layer or the like in an extrusion laminate configuration. This melt-extruded resin layer is preferably an olefin resin such as polyethylene or polypropylene. By using an extrusion-molten layer as the second substrate film, it is possible to achieve stronger adhesion to the ink layer surface, which has been roughened by the inclusion of silica. Furthermore, as such a material, both the first substrate film and the second substrate film are preferably polyolefin resins. The olefin ratio in the laminate is preferably 80% or more, more preferably 90% or more, and even more preferably 90% or more, from the viewpoint of improving recyclability.

[0064] (Other Layers) In addition to the above-described configuration, the laminate of the present invention may include any film (layer) depending on the purpose. Examples of other layers that can be used include a sealant film, a metal-vapor-deposited unstretched film, a metal-vapor-deposited stretched film, and a transparent vapor-deposited stretched film. Examples of the sealant film include a CPP film (unstretched polypropylene film) and an LLDPE film (linear low-density polyethylene resin film). Examples of the metal-vapor-deposited unstretched film include a VM-CPP film, which is a CPP film that has been vapor-deposited with a metal such as aluminum. Examples of the metal-vapor-deposited stretched film include a VM-OPP film, which is an OPP film that has been vapor-deposited with a metal such as aluminum. Examples of the transparent vapor-deposited stretched film include films obtained by vapor-depositing silica or alumina onto an OPP film, a PET film, a nylon film, or the like. Films with a coating applied to the vapor-deposited layer may also be used for purposes such as protecting the inorganic vapor-deposited layer of silica or alumina. Examples of the metal layer include aluminum foil.

[0065] The laminate having an ink layer formed using the liquid ink composition for laminate films of the present invention is not limited to the following embodiments, but examples thereof are preferred.

[0066] First, the modes of applying a primer layer onto a film corresponding to a first base film are as follows: (1-1) First base film / primer layer / ink layer / anchor coat layer / second base film / anchor coat layer / sealant film (1-2) First base film / primer layer / ink layer / anchor coat layer / second base film / anchor coat layer / metal layer / anchor coat layer / sealant film (1-3) First base film / primer layer / ink layer / anchor coat layer / metal layer / anchor coat layer / second base film / anchor coat layer / sealant film

[0067] In the above embodiments (1-1) to (1-3), a primer layer may be applied to both sides of the film positioned as an intermediate layer. (2-1) First substrate film / primer layer / ink layer / anchor coat layer / primer layer / second substrate film / primer layer / anchor coat layer / sealant film (2-2) First substrate film / primer layer / ink layer / anchor coat layer / primer layer / second substrate film / primer layer / anchor coat layer / metal layer / anchor coat layer / sealant film (2-3) First substrate film / primer layer / ink layer / anchor coat layer / metal layer / anchor coat layer / primer layer / second substrate film / primer layer / anchor coat layer / sealant film

[0068] In the above embodiments (1-1) to (1-3) and (2-1) to (2-3), a primer layer may be applied to the film corresponding to the second base film (the film located on the surface opposite to the first base film). (3-1) First base film / primer layer / ink layer / anchor coat layer / second base film / anchor coat layer / primer layer / sealant film (3-2) First base film / primer layer / ink layer / anchor coat layer / second base film / anchor coat layer / metal layer / anchor coat layer / primer layer / sealant film (3-3) First base film / primer layer / ink layer / anchor coat layer / metal layer / anchor coat layer / second base film / anchor coat layer / primer layer / sealant film (3-2-1) First base film / primer layer / ink layer / anchor coat layer / primer layer / second base film / primer layer / anchor coat layer / primer layer / sealant film (3-2-2) First base film / primer layer / ink layer / anchor coat layer / primer layer / second base film / primer layer / anchor coat layer / metal layer / anchor coat layer / primer layer / sealant film (3-2-3) First base film / primer layer / ink layer / anchor coat layer / metal layer / anchor coat layer / primer layer / second base film / primer layer / anchor coat layer / primer layer / sealant film

[0069] When producing the laminates of each of the above embodiments, if a primer layer is formed on the first substrate film, the primer layer may be formed by an in-line coating method in which a primer composition is applied during the film stretching process and then a stretching process is performed, or by an off-line coating method in which a primer composition is applied and dried after the film stretching process to form the primer layer.

[0070] The liquid ink composition of the present invention can be applied to a substrate using a known printing method such as gravure printing or flexographic printing. In addition to the gravure printing and flexographic printing described above, known printing methods that can be used include, for example, a T-die coater, a lip coater, a knife coater, a curtain coater, an inkjet printer, a bar coater, a roll coater, a spray coater, a comma coater, a reverse roll coater, a direct gravure coater, a reverse gravure coater, an offset gravure coater, a roll kiss coater, a reverse kiss coater, a kiss gravure coater, a reverse kiss gravure coater, an air doctor coater, a wire bar coater, a dip coater, a blade coater, a brush coater, a die slot coater, an offset printing machine, a screen printing machine, and the like, or a combination of two or more of these coating methods. When printing, the ink is diluted with a diluting solvent, for example, a mixture of an acetate ester-based organic solvent such as ethyl acetate or butyl acetate with an alcohol-based organic solvent such as ethyl alcohol, isopropyl alcohol or normal propyl alcohol, to a viscosity and concentration suitable for various printing methods such as gravure printing or flexographic printing, and then supplied to each printing unit either alone or in a mixture.

[0071] Examples of the base film 1 include an OPP film (a polypropylene film, for example, a biaxially oriented polypropylene film), a PET film (a polyethylene terephthalate film, for example, a biaxially oriented polyethylene terephthalate film), a nylon film, and a PE film (uniaxial (MDOPE) or biaxially oriented (BOPE)). The base film 1 may be coated to improve gas barrier properties or ink receptivity when a printing layer is provided. Commercially available coated base films 1 include K-OPP film and K-PET film. Other examples include transparent vapor-deposited OPP, PE, and PET films with high gas barrier properties, which are vapor-deposited with alumina or silica. Examples of the sealant film include a CPP film (a non-oriented polypropylene film) and an LLDPE film (a linear low-density polyethylene resin film). Examples of the metal layer include aluminum foil. Examples of the base film 2 include a nylon film. Examples of the sealant film include a CPP film (a non-oriented polypropylene film) and an LLDPE film (a linear low-density polyethylene resin film). Examples of the metal layer include aluminum foil. Examples of the base film 2 include nylon film. Examples of the sealant film include CPP film (unstretched polypropylene film) and LLDPE film (linear low-density polyethylene resin film). Examples of the metal layer include aluminum foil. Examples of the base film 2 include nylon film. From the viewpoint of improving recyclability, a mono-material structure is preferred, and it is particularly preferred to use an olefin-based material (PP, PE). Various known anchor coating agents are used for the anchor coating layer. Examples include isocyanate-based, polyethyleneimine-based, and polybutadiene-based materials, but the present invention is not limited to these materials.

[0072] <Uses of Laminates> The liquid ink composition of the present invention can be suitably used for packaging materials or electronic materials, such as an ink layer for electronic materials, building materials, textiles / leather, home appliances, vehicles such as cars and airplanes, furniture, office supplies, play equipment, sporting goods, or molded parts thereof. Therefore, a laminate having a primer layer formed with the liquid ink composition of the present invention can be applied to various molded products, such as electronic materials, building materials, textiles / leather, home appliances, vehicles such as cars and airplanes, furniture, office supplies, play equipment, sporting goods, or molded parts thereof. Furthermore, a laminate having an ink layer formed with the liquid ink composition of the present invention can also be applied to packaging materials (more specifically, multilayer packaging materials). It can also be used as a multilayer packaging material. When used as a multilayer packaging material, the layer structure can be changed depending on the contents, usage environment, and usage form. When used as a packaging material, for example, a product is produced using a packaging material formed from the laminate of the present invention by filling the contents through the opening and then heat-sealing the opening. The uses of the packaging material are not particularly limited, but it can be used as a packaging material for food, medicines, sanitary products, cosmetics, electronic equipment, building materials, industrial materials, etc., and is particularly suitable for use in electronic equipment.

[0073] <Properties of the Laminate> A laminate comprising the liquid ink composition of the present invention has excellent adhesion between the substrate and the ink layer, and the ink layer can be easily peeled from the substrate via the detachable primer layer. The laminate comprising the liquid ink composition of the present invention can be applied not only to laminates consisting only of an ink, a first substrate film, and a second substrate film, but also to laminates having structures such as those of the above embodiments (1-1) to (3-2-3), and has excellent recyclability.

[0074] [Recycled Material] As described above, the laminate of the present invention or a packaging material comprising the laminate can be processed as is using various known recycling plastic processing methods and used as a recycled material. A recycled material can be obtained by a production method including the steps of crushing the laminate of the present invention or the packaging material, melting and kneading the crushed film pieces, and pelletizing the melt-kneaded mixture. The binder resin used in the laminate of the present invention has a low chlorine content, and is therefore advantageous in that it does not generate chlorine-based gases even when heated and reprocessed, thereby reducing the risk of equipment deterioration.

[0075] [Method for producing recycled substrate] Furthermore, the substrate film (i.e., recycled substrate) can be obtained again by removing the detachable primer layer from the laminate according to the present invention. An example of a method for removing the detachable primer layer from the laminate using an alkaline solution is described below.

[0076] The primer layer can be removed from the substrate by, for example, immersing it in a warm alkaline solution. The alkaline solution used to remove the primer layer is not particularly limited, and examples of the alkaline substance include sodium hydroxide (NaOH), potassium hydroxide (KOH), calcium hydroxide (Ca(OH) ２ ), ammonia, etc. are preferred. NaOH or KOH is preferred. In a method for producing an alkaline aqueous solution, NaOH, KOH, ammonia, etc. may be uniformly dissolved or dispersed in water, and the resulting solution may be appropriately adjusted to a specified concentration or pH.

[0077] In the case of the laminate of the above embodiment (1-1), the primer layer is sandwiched between plastic films, and it takes a considerable amount of time for the alkaline aqueous solution to reach the primer layer, but it is more preferable that delamination proceeds in a short time. The immersion time is preferably within 24 hours, more preferably within 12 hours, and even more preferably within 6 hours.

[0078] In this way, the primer layer can be removed by immersing the laminate in a warm alkaline solution. That is, by treating the laminate with a warm alkaline solution and removing the ink layer together with the primer layer from the first substrate film, a recycled first substrate film can be obtained. The same applies to laminates having a laminate type structure, and according to the present invention, the laminate can be treated with a warm alkaline solution and removing the ink layer and / or the second substrate film together with the primer layer from the first substrate film to obtain a recycled first substrate film, or a recycled first substrate film and a recycled second substrate film or sealant film.

[0079] [Method for Producing Recycled Plastic Pellets] Furthermore, the recycled substrate obtained by the above-described method for producing recycled substrates can be molded using a molding machine to obtain recycled plastic pellets. The crushing (pulverization) process can be carried out using any known crusher, and is not particularly limited. The crushed film pieces are then physically blended using melt kneading, solvent cast blending, latex blending, polymer complexing, or the like. Melt kneading is particularly common. Examples of kneading devices include tumblers, Henschel mixers, rotary mixers, super mixers, ribbon tumblers, and V-blenders. The film pieces are melt-kneaded using such kneading devices and then pelletized. A single-screw or multi-screw extruder is typically used for melt kneading and pelletization. The film pieces may be fed as is or may be subjected to compression and volume reduction treatment with or without heating before being fed. In addition to these extruders, Banbury mixers, rollers, Ko-kneaders, blast mills, Prabender-Bloutographs, and the like can also be used, and these can be operated batchwise or continuously. Alternatively, the recycled plastic pellets may be used as a molding resin and melt-kneaded in the heating barrel of a molding machine without being melt-kneaded. The recycled plastic pellets may be plastics that have been deinked and delaminated, or a laminate that has not been deinked or delaminated may be used as is. However, the former has higher purity and is therefore more valuable as a recycled material. Therefore, it is possible to process films using the recycled plastic pellets obtained by the present invention.

[0080] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. In the following examples, "%" in the compositions means "% by mass."

[0081] 1. Measurement and Evaluation Methods Used in Examples and Comparative Examples The liquid ink compositions obtained in the examples and comparative examples described below were evaluated using the following test methods.

[0082] (Amine Value) The amine value is the amount of potassium hydroxide (mg) equivalent to the amount of hydrochloric acid required to neutralize the amino groups contained in 1 g of sample, and was measured in accordance with JIS K 0070. Specifically, 0.5 g to 2 g of sample was precisely weighed (sample solids content: S g). 50 mL of a 60 / 40 (mass ratio) mixed solution of methanol and methyl ethyl ketone was added to the precisely weighed sample to dissolve it. Bromophenol blue was added as an indicator to the resulting solution, and the resulting solution was titrated with a 0.2 mol / L ethanolic hydrochloric acid solution (titer: f). The point at which the color of the solution changed from green to yellow was set as the endpoint, and the titration volume (A mL) at this point was used to calculate the amine value according to the following formula: (Formula) Amine value = (A × f × 0.2 × 56.108) / S [mg KOH / g]

[0083] (Particle Size Distribution) In the examples of the present invention, Sylisia 350 and 780 manufactured by Fuji Silysia Ltd., having the distributions shown in Table 1, were used.

[0084] (Acid Value) The acid value was determined as the number of mg of KOH required when the COOH groups contained in 1 g of urethane resin were titrated by the potassium hydroxide method.

[0085] (Weight Average Molecular Weight) The weight average molecular weight (Mw) was measured using gel permeation chromatography (GPC).

[0086] (Urethane Bond Concentration) The urethane bond concentration was calculated by the method using the above-mentioned formula (2).

[0087] (Urea binding concentration) The urea binding concentration was calculated by the method using the above-mentioned formula (3).

[0088] (Two-component stability) The liquid ink compositions described in the Examples and Comparative Examples were placed in glass bottles, and 4% by mass of CVL No. 10 hardener (isocyanate curing agent, manufactured by DIC) was added to 100% by mass of each liquid ink composition. After storing at 40°C for 24 hours, the viscosity was measured and the change in viscosity from before storage was evaluated on a 5-point scale from 1 to 5. 5: No viscosity change - Viscosity change of less than 2 seconds. 4: Slight viscosity change - Viscosity change of 2 to less than 5 seconds. 3: Slightly significant viscosity change - Viscosity change of 5 to less than 10 seconds. 2: Significant viscosity change - Viscosity change of 10 to less than 15 seconds. 1: Very significant viscosity change - Viscosity change of 15 seconds or more.

[0089] (Dry Lamination Strength) A laminate (OPP film (P2161 manufactured by Toyobo) / ink layer / anchor coat layer (LX470, SI75) / CPP film) was prepared, and the printed surface of the ink layer was coated with a urethane-based dry lamination adhesive, DIC Dry LX-470 / SI75 (manufactured by DIC Engineering), using a dry laminator (manufactured by DIC Engineering). An unstretched polypropylene film was laminated on the adhesive-coated surface and aged at 40°C for 3 days to obtain a laminate. The obtained laminate was cut into a width of 15 mm and subjected to a 90-degree peel test at a pulling speed of 300 mm / min.

[0090] (Non-solvent (solvent-free adhesive) laminate appearance) For the evaluation of the non-solvent laminate appearance, the same laminate as that produced for the strength evaluation was coated with DIC's solvent-free adhesive 2K-SF-900A / HA-930B at a coating amount of 2 g / m using a non-solvent laminator. ２ The laminate was laminated in a composition of OPP film (P2161 manufactured by Toyobo) / ink / solvent-free adhesive / aluminum-deposited CPP film (Toray Film Processing 2203), and the appearance after lamination was evaluated and rated according to the following criteria A and B. [Evaluation criteria] A: No defective appearance (glitter) on the particles, and high hiding power. B: Defective appearance (glitter) on the particles, and low hiding power.

[0091] (Extrusion Laminate (PEEL) Strength) The viscosity of the liquid ink compositions described in the Examples and Comparative Examples was adjusted with ethyl acetate to 16 seconds (25°C) using a Zahn cup #3 (manufactured by Rigo Co., Ltd.), and a print was produced using an OPP film P2161 (thickness: 20 μm) manufactured by Toyobo Co., Ltd., using a gravure proofing machine equipped with a gravure plate with a plate depth of 35 μm. 0.1 g / m of a polyethyleneimine-based anchor coating agent was applied to this print. ２ After application, molten polyethylene was laminated to a thickness of 40 μm using an extrusion laminator to obtain a laminated product. The laminated film was then cut into a width of 15 mm and subjected to a 90-degree peel test (measurement of PEEL strength) at a pulling rate of 50 mm / min to measure the PEEL strength (N / 15 mm).

[0092] (Cellophane tape adhesion) The viscosity of the liquid ink compositions described in the Examples and Comparative Examples was adjusted with ethyl acetate to 16 seconds (25°C) using a Zahn cup #3 (manufactured by Rigo Co., Ltd.), and printed matter was produced using OPP film P2161 (thickness: 20 μm) manufactured by Toyobo Co., Ltd., using a gravure proofing machine equipped with a gravure plate with a plate depth of 35 μm. After leaving it for one day, cellophane tape (manufactured by Nichiban Co., Ltd., 12 mm wide) was applied to the printed surface, and the tape was quickly peeled off, and the appearance of the ink layer was evaluated on a 5-point scale of 1 to 5 as follows. In addition, the cellophane tape adhesion was similarly evaluated for the following substrate films: corona-treated polyester film (hereinafter referred to as PET film) Ester E5102 (thickness: 12 μm) manufactured by Toyobo Co., Ltd.; corona-treated nylon film (hereinafter referred to as NY film) Emblem ON (thickness: 15 μm) manufactured by Unitika Ltd.; and alumina-deposited transparent PET film IB-PET-PUB (thickness: 12 μm) manufactured by Dai Nippon Printing Co., Ltd. [Evaluation criteria] 5: No ink layer peeled off at all. 4: 80% or more of the ink layer remained on the film. 3: 50% to 80% of the ink layer remained on the film. 2: 30% to 50% of the ink layer remained on the film. 1: Less than 30% of the ink layer remained on the film.

[0093] (Blocking Resistance) The viscosity of the liquid ink compositions described in the Examples and Comparative Examples was adjusted with ethyl acetate to 16 seconds (25°C) using a Zahn cup #3 (manufactured by Rigo Co., Ltd.), and the films were superimposed on each other so that the printed surface and non-printed surface of a printed matter made using OPP film P2161 (thickness: 20 µm) manufactured by Toyobo Co., Ltd. were in contact with each other using a gravure proofing machine equipped with a gravure plate with a plate depth of 35 µm. ２ The test pieces were left to stand for 12 hours under a load of 1000 kJ / cm² and kept at 40°C. After removal, the state of ink transfer to the non-printed side was evaluated using the following five-point scale of 1 to 5. Blocking resistance was also evaluated using the following substrate films: corona-treated polyester film (hereinafter referred to as PET film) Ester E5102 (thickness: 12 μm) manufactured by Toyobo Co., Ltd.; corona-treated nylon film (hereinafter referred to as NY film) Emblem ON (thickness: 15 μm) manufactured by Unitika Ltd.; and alumina-deposited transparent PET film IB-PET-PUB (thickness: 12 μm) manufactured by Dai Nippon Printing Co., Ltd. [Evaluation Criteria] 5: No ink transfer was observed with 0% ink transfer to the non-printed side; 4: Transfer was observed at a rate of less than 10%; 3: Transfer was observed at a rate of 10% to less than 20%; 2: Transfer was observed at a rate of 20% to less than 30%; and 1: Transfer was observed at a rate of 30% or more.

[0094] (Light-shielding properties) For the light-shielding laminates described in the examples and comparative examples, the light transmittance for light of 450 nm or more and 550 nm or less was measured using an ultraviolet / visible / near-infrared spectrophotometer UV-3600 manufactured by Shimadzu Corporation, and evaluated on a five-level scale of 1 to 5 as follows: [Evaluation criteria] 5: Transmittance less than 10%. 4: Transmittance of 10% or more and less than 15%. 3: Transmittance of 10% or more and less than 20%. 2: Transmittance of 20% or more and less than 30%. 1: Transmittance of 30% or more.

[0095] 2. Preparation of liquid ink compositions of examples and comparative examples

[0096] (2-1) Silica Particles First, for the silica particles used in the Examples and Comparative Examples, Sylisia 350 and 780 manufactured by Fuji Silysia Ltd. were prepared. According to the volume-based particle size distribution values ​​listed in the inspection table, the cumulative 90% particle diameter (D90), cumulative 50% particle diameter (D50), cumulative 10% particle diameter (D10), and (D90-D10) / D50 values ​​of the particle size distribution of each silica were as shown in Table 1 below.

[0097]

[0098] (2-1) Polyurethane Resin The raw materials used in the synthesis of the polyurethane resins in the examples and comparative examples are as follows: IPDI: isophorone diisocyanate Polyol A: Polyertes polyol composed of adipic acid / neopentyl glycol (weight average molecular weight Mw: 2000) Polyol B: Polyertes polyol composed of adipic acid / 2-methylpropanediol (weight average molecular weight Mw: 2000) Polyol C: Polyertes polyol composed of sebacic acid / neopentyl glycol / propylene glycol (weight average molecular weight Mw: 2000) IPDA: isophorone diamine CHA: cyclohexylamine Polyurethane resin 1 was synthesized from the above raw materials as follows. A four-neck flask equipped with a stirrer, thermometer, reflux condenser, and nitrogen gas inlet tube was charged with 49.84 g of IPDI, 231.25 g of polyol A, and 0.03 g of urethane catalyst DICNATE 425. The mixture was reacted at 85°C for 6 hours under a nitrogen stream to obtain prepolymer A. Prepolymer A was added to a mixed solution containing 490 g of ethyl acetate, 210 g of IPA, 17.1 g of IPDA, and 1.81 g of CHA, and the mixture was reacted at 40°C for 4 hours under a nitrogen stream to obtain polyurethane resin 1. The composition and physical properties of polyurethane resin 1 are shown in Table 1 below. The nonvolatile content, amine value, weight average molecular weight (Mw), urethane bond concentration, and urea bond concentration in polyurethane resin 1 are also shown in Table 1.

[0099] Polyurethanes 2 to 6 were prepared in the same manner as polyurethane resin 1, except that the composition was changed as shown in Table 1 below. The compositions and physical properties of polyurethane resins 2 to 6 are shown in Table 2.

[0100]

[0101] (2-2) Liquid Ink Composition Example 1 Then, 30.0 parts by mass of the obtained polyurethane resin 1, 30.0 parts by mass of titanium oxide (R-780), 0.5 parts by mass of silica (Sylisia350), 41.5 parts by mass of ethyl acetate, and 5.0 parts by mass of isopropyl alcohol were mixed and kneaded to prepare a liquid ink composition for laminate film according to Example 1.

[0102] Examples 2 to 14 Liquid ink compositions for laminate films according to Examples 2 to 14 were prepared using the compositions and composition ratios shown in Tables 3 and 4 below, in the same manner as in Example 1. The liquid ink compositions obtained in Examples 1 to 14 were subjected to the various evaluations described above.

[0103] Comparative Examples 1 to 5 Liquid ink compositions for laminate films according to Comparative Examples 1 to 5 were prepared using the compositions and composition ratios shown in Table 5 below, in the same manner as in Example 1. The liquid ink compositions obtained in Comparative Examples 1 to 5 were subjected to the various evaluations described above.

[0104] Examples 15 to 19 Liquid ink compositions for laminate films according to Examples 15 to 19 were prepared using the compositions and composition ratios shown in Table 6 below, in the same manner as in Example 1. The names S1 to S4 and S11 given for the convenience of preparing the various laminates and their color tones as their appearances are also shown in Table 6. The liquid ink compositions obtained in Examples 15 to 19 were subjected to the various evaluations described above.

[0105] Comparative Examples 6 to 13 Liquid ink compositions for laminate films according to Comparative Examples 6 to 13 were prepared using the compositions and composition ratios shown in Table 7 below, in the same manner as in Example 1. The names S5 to S13 given for the convenience of preparing the various laminates and their color tones as their appearances are also shown in Table 7. The liquid ink compositions obtained in Comparative Examples 6 to 13 were subjected to the various evaluations described above.

[0106]

[0107]

[0108]

[0109]

[0110]

[0111] The experimental results in Tables 3 to 7 show that the liquid ink resin compositions for laminate films according to Comparative Examples 1 to 3, 12, and 13, which did not use silica, had PEEL strengths of 1.0 or less and blocking resistance was also evaluated as 3 or less, while the liquid ink resin compositions for laminate films according to Comparative Examples 4, 6, 8, and 10, which used polyurethane resin 5 having an amine value of 0.1 mgKOH / g or less, had PEEL strengths of 1.0 or less and cellophane tape adhesion was also evaluated as 3 or less. Furthermore, the liquid ink resin compositions for laminate films according to Comparative Examples 5, 7, 9, and 11, which used polyurethane resin 6 having an amine value of 10 mgKOH / g or more, showed poor two-component stability. From this, it was found that the liquid ink compositions for laminate films of Examples 1 to 19, which used a polyurethane resin with an amine value of 0.1 mgKOH / g or more and 10 mgKOH / g or less and silica, all became liquid ink resin compositions with excellent blocking resistance, adhesion to the substrate, (extrusion) laminate strength, and two-component stability.

[0112] (2-3) Light-shielding laminate Example 20 Next, the liquid ink resin compositions obtained in Examples 15 (S1) and 16 (S2) were applied by solid printing onto an OPP substrate in the order of ink layer 1 (S1) and ink layer 2 (S2) as shown in Table 8 below, to prepare an ink layer print. A polyethyleneimine-based anchor coating agent was applied to the prepared ink layer print in an amount of 0.1 g / m. ２ After the coating, molten polyethylene was laminated to a thickness of 40 μm using an extrusion laminator to prepare a light-shielding laminate.

[0113] Examples 21 to 25 Using the liquid ink compositions for laminate films of Examples 15 to 19 with the compositions and composition ratios shown in Table 8 below, light-shielding laminates of Examples 21 to 25 were produced in the same manner as in Example 20. The light-shielding laminates obtained in Examples 21 to 25 were subjected to the various evaluations described above, and the results are shown in Table 8.

[0114] Comparative Examples 14 to 17 Using the liquid ink compositions for laminate films according to Example 1 and Comparative Examples 6 to 8, 12, and 13 with the compositions and composition ratios shown in Table 9 below, light-shielding laminates according to Comparative Examples 14 to 17 were produced in the same manner as in Example 20. The light-shielding laminates obtained in Comparative Examples 14 to 17 were subjected to the various evaluations described above, and the results are shown in Table 9.

[0115]

[0116]

[0117] The experimental results in Tables 8 and 9 above show that light-shielding laminates excellent in both the light-shielding property of the laminate film and the extrusion laminate PEEL strength were obtained when the liquid ink compositions for laminate films according to Examples 15 to 19 were used. On the other hand, the light-shielding laminates obtained when the liquid ink compositions for laminate films according to Comparative Examples 6 to 8, 12, and 13 were used either had a light-shielding property of the laminate film of 10% or more, an extrusion laminate PEEL strength of 1.0 or less, or were not excellent in two-component stability to begin with.

[0118] According to the present invention, it is possible to provide a liquid ink resin composition for laminate films that is excellent in all of blocking resistance, adhesion to substrates, (extrusion) lamination strength, and two-component stability. Furthermore, the present invention can provide a laminate using the liquid ink composition for laminate films that satisfies the above properties, a recycled material using the laminate, a method for producing a recycled substrate using the laminate, and a method for producing recycled plastic pellets using the recycled substrate.

[0119] [Contribution to the United Nations-led Sustainable Development Goals (SDGs)] The SDGs have been proposed to realize a sustainable society. One embodiment of the present invention is thought to be a technology that can contribute to goals such as "No. 7: Affordable and Clean Energy" and "No. 12: Responsible Consumption and Production."

Claims

1. It contains at least a binder resin, silica, and an organic solvent. The binder resin comprises a polyurethane resin having a solid content amine value of 0.1 mg KOH / g or more and 10 mg KOH / g or less. The cumulative 50% particle size (D50) of the volume-based particle size distribution of the silica is 1 μm or more and 10 μm or less, and the following formula (1) is used using the cumulative 90% particle size (D90), cumulative 50% particle size (D50), and cumulative 10% particle size (D10) of the particle size distribution. (D90-D10) / D50<1.9... (1) A liquid ink composition for laminating film, represented by [formula].

2. The liquid ink composition for laminating film according to claim 1, wherein the silica content is 0.1% by mass or more and 7.0% by mass or less with respect to the total solid content of the liquid ink composition for laminating film.

3. The binder resin further comprises one or more resins selected from the group consisting of cellulose resins, polyester resins, acrylic resins, polyamide resins, rosin-modified maleic acid resins, polyvinyl butyral resins, vinyl chloride vinyl acetate copolymers, chlorinated polypropylene, and ketone aldehyde resins. The liquid ink composition for laminating film according to claim 1.

4. The chlorine content of the binder resin is 5% by mass or less. The liquid ink composition for laminating film according to claim 1.

5. A liquid ink composition for laminating film according to any one of claims 1 to 4, for use in extrusion lamination.

6. It has a first base film, an ink layer, and a second base film in this order. A laminate in which the ink layer is a layer made of the liquid ink composition for laminate film described in any one of claims 1 to 4.

7. The aforementioned ink layer is a light-shielding printing layer and comprises at least a white ink layer containing titanium dioxide and a non-white colored ink layer containing aluminum paste, carbon black, or an organic pigment. The laminate according to claim 6, wherein the white ink layer and the colored ink layer are ink layers formed by solid printing.

8. The laminate according to claim 6, wherein the second base film includes a melt-extruded resin layer.

9. An anchor coat layer is provided between the ink layer and the second substrate film. The anchor coat layer is made of one or more resins selected from the group consisting of polyethyleneimine resins, polybutadiene resins, and polyisocyanate resins. The laminate according to claim 6.

10. Both the first base film and the second base film are made of polyolefin resin. The laminate according to claim 6.

11. A desorption primer layer is provided between the first substrate film and the ink layer, or between the ink layer and the second substrate film, or in either case or both. The laminate according to claim 6.

12. The aforementioned desorption primer layer is soluble in alkaline solutions. The laminate according to claim 11.

13. A recycled material using the laminate described in claim 6.

14. A method for producing a recycled substrate, comprising removing the ink layer from the laminate by dissolving the desorption primer layer in the laminate according to claim 12 using an alkaline solution treatment.

15. A method for producing recycled plastic pellets, comprising molding a recycled substrate obtained by the method for producing a recycled substrate described in claim 14 using a molding machine.