Liquid ink composition, and printed matter and layered product using said liquid ink composition

Abstract

Provided are: a liquid ink composition which contains a pigment, a binder resin, an organic solvent, silica, and a wax, and in which the binder resin contains a polyurethane resin (A) and a polyvinyl butyral resin (B); printed matter obtained through printing using the same; a laminate layered product; and a packaging material. The liquid ink composition, despite being an environmentally friendly ink in which a chlorine-based resin is not used, exhibits excellent highlight transferability, which is one of printing properties, and excellent blocking resistance after printing, and has good adhesion to a base material and is suitable for laminate printing.

Description

Liquid ink composition, and printed matter and laminate using said liquid ink composition

[0001] The present invention relates to a liquid ink composition that can be used as a laminate gravure ink or flexographic ink for flexible packaging, and to a printed matter and a laminate using the liquid ink composition.

[0002] Gravure inks and flexographic inks are widely used to impart beauty and functionality to printed materials. When gravure- or flexographically printed materials are used as packaging materials, especially food packaging, they are typically laminated. In this case, various printing materials and lamination processes are used depending on the type of contents and intended use.

[0003] From the viewpoints of both work hygiene during printing and the harmfulness of packaging materials, the use of aromatic solvents such as toluene and ketone solvents such as methyl ethyl ketone as solvents for these printing inks is being restricted. For example, Patent Documents 1 and 2 describe the addition of carboxylic acids to inks that do not use toluene, methyl ethyl ketone, or the like in order to improve viscosity stability and adhesion.

[0004] In recent years, legal regulations surrounding food packaging in particular have become stricter worldwide, with stricter regulations on the ingredients used in packaging and their migration into food. Furthermore, with the aim of realizing a sustainable society, there is a demand to design inks and packaging components using materials that are guaranteed to be safe for both the human body and the environment.

[0005] For example, polyurethane resins and vinyl chloride-vinyl acetate copolymer resins (hereinafter referred to as "PVC") have been widely used as binder resins for printing inks. These resins are a binder combination that can achieve both excellent dispersibility and high film properties, and are essential ink ingredients for achieving various properties required for laminating inks, such as good printability, anti-blocking properties after printing, adhesion to substrates, lamination strength, and boiling retort properties.

[0006] However, PVC has the following issues, raising concerns about its role as a substance that hinders packaging recycling. First, there is an issue related to chemical recycling. Plastic waste discharged as general waste includes various plastics, including chlorine-based resins such as polyvinyl chloride and polyvinylidene chloride. These chlorine-based resins release hydrogen chloride during the thermal decomposition process of recycling, generating hydrochloric acid, which can corrode equipment and piping. Second, there is an issue related to thermal recycling. In methods for reusing energy generated when waste is incinerated, the presence of chlorine-based resins during incineration poses a problem, as environmental hormones such as dioxins are emitted during incineration. Therefore, there is a need for the development of an ink that has the physical properties required for laminating inks without using chlorine-based materials such as PVC (see Patent Document 3).

[0007] One of the issues with inks that do not use chlorine-based resins is that highlight transfer, which is one of the printing suitabilities, is difficult to maintain, and blocking resistance after printing is reduced. Highlight transfer occurs due to plate fogging and plate clogging during gravure printing, both of which lead to staining of the printed surface. Furthermore, if blocking occurs after printing, offset and other problems occur when the film is wound after printing, which also leads to staining of the printed surface. Therefore, further improvements are being attempted to find inks that can satisfy these issues.

[0008] JP 2019-6909 A JP 2021-8544 A JP 2022-96163 A

[0009] The present invention aims to provide a liquid ink composition that is an environmentally friendly ink that does not use chlorine-based resins, yet has excellent highlight transferability, which is one of the printability characteristics, and excellent blocking resistance after printing, and has good adhesion to substrates, making it suitable for laminate printing.

[0010] That is, the present invention provides a liquid ink composition comprising a pigment, a binder resin, an organic solvent, silica, and a wax, wherein the binder resin comprises a polyurethane resin (A) and a polyvinyl butyral resin (B).

[0011] Furthermore, the present invention relates to a printed matter obtained by printing the liquid ink composition.

[0012] Furthermore, the present invention relates to a laminate having a printed layer formed by printing the liquid ink composition.

[0013] Furthermore, the present invention relates to a packaging material containing the laminate.

[0014] The present invention can provide a liquid ink composition that is suitable for laminate printing, as it is an environmentally friendly ink that does not use chlorine-based resins, yet has excellent highlight transferability, which is one of the printability characteristics, and excellent blocking resistance after printing, and has good adhesion to substrates.

[0015] The present invention will be described in detail. (Definition of Terms) In the present invention, the 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 is preferably gravure ink or flexographic ink. The liquid ink of the present invention does not contain any active energy-curable component, i.e., it is a liquid ink that is non-reactive to active energy rays. Note that in the following description, all "ink" refers to "printing ink." All "parts" refer to "parts by mass," "total amount of ink" refers to the total amount of ink including all volatile components such as organic solvents, and "total amount of ink solids" refers to the total amount of only non-volatile components, excluding volatile components.

[0016] The liquid ink composition of the present invention is a liquid ink composition containing a pigment, a binder resin, an organic solvent, silica, and a wax, and is characterized in that the binder resin contains a polyurethane resin (A) and a polyvinyl butyral resin (B).

[0017] (Polyurethane Resin (A)) The polyurethane resin (A) functions as a binder resin to improve ink adhesion, and also functions as a pigment dispersing resin. The polyurethane resin (A) is preferably made from polyester polyol and polyether polyol as reaction raw materials, with the mass ratio of the polyester polyol being higher in the total mass of the polyester polyol and polyether polyol. That is, the polyol structure of the polyurethane resin (A) preferably contains structural units derived from polyester polyol, which can improve laminate strength. Furthermore, the polyether polyol structure preferably contains structural units derived from polyether polyol, which can improve ink dispersibility and fluidity and also improve adhesion.

[0018] Specifically, the mass ratio of polyester polyol to polyether polyol in the polyol structure is preferably in the range of 45:55 to 100:0, more preferably in the range of 55:45 to 100:0, and even more preferably in the range of 80:20 to 99:1. A mass ratio of polyester polyol to polyether polyol within the range of 45:55 to 100:0 is preferred because it allows for printed matter that is less prone to blocking to be obtained. A mass ratio within the range of 80:20 to 99:1 is preferred because it allows for an ink that is particularly excellent in lamination strength, adhesion, and ink dispersibility to be obtained. Furthermore, when polyvinyl butyral resin (B) is used in combination, a mass ratio of polyester polyol to polyether polyol within the range of 80:20 to 99:1 provides good compatibility, allowing for favorable storage stability and flowability.

[0019] 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.

[0020] 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, and 2-butyl-2-ethyl-1,3 Glycols having a branched structure such as 2-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.

[0021] 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 its anhydride; benzenetetracarboxylic acid, benzenepentacarboxylic acid, benzenehexacarboxylic acid, and the anhydrides of these acids.

[0022] The polyester polyol may be any of various known polyester polyols generally used in the production of polyurethane resin (A), 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.

[0023] 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. In the present invention, the number average and weight average molecular weights are values ​​measured by gel permeation chromatography (GPC) under the following conditions:

[0024] Measurement apparatus: High-speed GPC apparatus ("HLC-8220GPC" manufactured by Tosoh Corporation) Column: The following columns manufactured by Tosoh Corporation were used, connected in series: "TSKgel G5000" (7.8 mm I.D. x 30 cm) x 1, "TSKgel G4000" (7.8 mm I.D. x 30 cm) x 1, "TSKgel G3000" (7.8 mm I.D. x 30 cm) x 1, "TSKgel G2000" (7.8 mm I.D. x 30 cm) x 1 Detector: RI (differential refractometer) Column temperature: 40°C Eluent: Tetrahydrofuran (THF) Flow rate: 1.0 mL / min Injection volume: 100 μL (tetrahydrofuran solution with a sample concentration of 0.4% by mass) Standard sample: A calibration curve was prepared using the following standard polystyrene.

[0025] [Standard polystyrene] "TSKgel Standard Polystyrene A-500" manufactured by Tosoh Corporation "TSKgel Standard Polystyrene A-1000" manufactured by Tosoh Corporation "TSKgel Standard Polystyrene A-2500" manufactured by Tosoh Corporation "TSKgel Standard Polystyrene A-5000" manufactured by Tosoh Corporation "TSKgel Standard Polystyrene F-1" manufactured by Tosoh Corporation "TSKgel Standard Polystyrene F-2" manufactured by Tosoh Corporation "TSKgel Standard Polystyrene F-4" manufactured by Tosoh Corporation "TSKgel Standard Polystyrene F-10" manufactured by Tosoh Corporation "TSKgel Standard Polystyrene F-20" manufactured by Tosoh Corporation "TSKgel Standard Polystyrene F-40" manufactured by Tosoh Corporation "TSKgel Standard Polystyrene F-80" manufactured by Tosoh Corporation "TSKgel Standard Polystyrene F-128" manufactured by Tosoh Corporation "TSKgel Standard Polystyrene F-288" manufactured by Tosoh Corporation "TSKgel Standard Polystyrene F-550" manufactured by Tosoh Corporation

[0026] As the polyether polyol, various known polyether polyols commonly used in the production of polyurethane resin (A) can be used, and one or more of them may be used in combination. Examples include polyether polyols of polymers or copolymers of methylene oxide, ethylene oxide, propylene oxide, tetrahydrofuran, etc. Specific examples include known, general-purpose polyether polyols such as polyethylene glycol, polypropylene glycol, and polytetramethylene glycol. The inclusion of a polyether polyol significantly improves adhesion, particularly on high-performance barrier films, resulting in excellent blocking resistance and laminate strength.

[0027] The polyether polyol preferably has a number-average molecular weight of 100 to 3500, more preferably 100 to 2000, and even more preferably 100 to 1000. If the number-average molecular weight of the polyether polyol is less than 100, the polyurethane resin (A) film tends to be hard, resulting in reduced adhesion to polyester films. If the number-average molecular weight is greater than 3500, the polyurethane resin (A) film tends to be brittle, resulting in reduced blocking resistance of the ink film.

[0028] The polyether polyol is preferably contained in the range of 1% by mass to 50% by mass, more preferably 1% by mass to 40% by mass, per 100 parts by mass of the polyurethane resin (A). When the polyether polyol is 1% by mass or more per 100 parts by mass of the polyurethane resin (A), the solubility of the polyurethane resin (A) in ketone, ester, and alcohol-based solvents is ensured, resulting in good adhesion to high-performance barrier films. Furthermore, the resolubility of the ink film in the solvent is improved, resulting in improved tone reproducibility of printed matter. Furthermore, when the polyether polyol is 50% by mass or less, the ink film has adequate flexibility, which tends to result in good blocking resistance.

[0029] In addition, as a polyol to be used in combination with the polyurethane resin (A) used in the liquid ink composition of the present invention, various known polyols generally used in the production of polyurethane resin (A) can be used, and one or more of them may be used in combination. Examples include 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.

[0030] In addition, when the above-mentioned combined polyol contains a polyester polyol and / or a polyether polyol, the content of the polyester polyol and / or the polyether polyol contained in the combined polyol is also included in the polyester polyol and / or the polyether polyol mass in the polyol structure of the polyurethane resin (A), respectively.

[0031] The diisocyanate compound used in the polyurethane resin (A) in the liquid ink composition of the present invention includes various known aromatic diisocyanates, aliphatic diisocyanates, alicyclic diisocyanates, etc. that are generally used in the production of polyurethane resins (A). 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-1,4-diisocyanate, methyl methyl ether diisocyanate, ... Examples of the diisocyanate 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.

[0032] Examples of chain extenders used in the polyurethane resin (A) in the liquid ink composition of the present invention include ethylenediamine, propylenediamine, hexamethylenediamine, diethylenetriamine, triethylenetetramine, isophoronediamine, and dicyclohexylmethane-4,4'-diamine. In addition, amines containing hydroxyl groups in the molecule, such as 2-hydroxyethylethylenediamine, 2-hydroxyethylpropyldiamine, 2-hydroxyethylpropylenediamine, di-2-hydroxyethylethylenediamine, di-2-hydroxyethylenediamine, di-2-hydroxyethylpropylenediamine, 2-hydroxypropylethylenediamine, di-2-hydroxypropylethylenediamine, and di-2-hydroxypropylethylenediamine, can also be used. These chain extenders can be used alone or in combination of two or more. Furthermore, monovalent active hydrogen compounds can also be used as end-blocking agents for the purpose of terminating the reaction. Examples of such compounds include dialkylamines such as di-n-butylamine, and alcohols such as ethanol and isopropyl alcohol. Furthermore, when it is particularly desired to introduce a carboxyl group into the polyurethane resin (A), an amino acid such as glycine or L-alanine can be used as a reaction terminator. These end-capping agents can be used alone or in combination of two or more.

[0033] The polyurethane resin (A) in the liquid ink composition of the present invention can be produced, for example, by a two-stage process in which polypropylene glycol and a co-used polyol are reacted with a diisocyanate compound in a proportion such that the isocyanate groups are in excess to obtain a prepolymer having terminal isocyanate groups, and the resulting prepolymer is then reacted with a chain extender and / or a terminal blocking agent in a suitable solvent, i.e., an ester solvent commonly used as a solvent for non-toluene gravure inks, such as ethyl acetate, propyl acetate, or butyl acetate; a ketone solvent such as acetone, methyl ethyl ketone, or methyl isobutyl ketone; an alcohol solvent such as methanol, ethanol, isopropyl alcohol, or n-butanol; a hydrocarbon solvent such as methylcyclohexane or ethylcyclohexane; or a mixture thereof; or by a one-stage process in which polypropylene glycol, a co-used polyol, a diisocyanate compound, a chain extender, and / or a terminal blocking agent are reacted all at once in a suitable solvent selected from the above. Of these processes, the two-stage process is preferred for obtaining a uniform polyurethane resin (A). Furthermore, when producing polyurethane resin (A) by a two-stage method, it is preferable to react the chain extender and / or end-capping agent so that the total equivalent ratio of amino groups in the chain extender and / or end-capping agent is 1 / 0.9 to 1.3. If the equivalent ratio of isocyanate groups to amino groups is less than 1 / 1.3, the chain extender and / or end-capping agent may remain unreacted, causing the polyurethane resin (A) to yellow or emitting an odor after printing. Furthermore, in recent years, from the viewpoint of the working environment, it is more preferable not to use aromatic solvents such as toluene and xylene or ketone solvents.

[0034] The weight-average molecular weight of the polyurethane resin (A) thus obtained is preferably within the range of 15,000 to 100,000, and more preferably within the range of 15,000 to 80,000. If the weight-average molecular weight of the polyurethane resin (A) is less than 15,000, the blocking resistance of the resulting ink composition and the strength and oil resistance of the printed film tend to be reduced, while if it exceeds 100,000, the viscosity of the resulting ink tends to be high and the gloss of the printed film tends to be reduced.

[0035] The content of the polyurethane resin (A) used in the liquid ink composition of the present invention in the ink (solids content of the polyurethane resin (A)) is preferably 4% by mass or more, relative to the total mass of the ink, from the viewpoint of ensuring sufficient adhesion of the ink to the substrate, and 25% by mass or less, more preferably in the range of 6 to 15% by mass, from the viewpoint of appropriate ink viscosity and work efficiency during ink production and printing. Furthermore, the lower limit of the solids mass ratio in the ink is preferably 5% by mass, more preferably 10% by mass, more preferably 15% by mass, and even more preferably 20% by mass. Furthermore, the upper limit of the solids mass ratio in the ink is preferably 95% by mass, more preferably 90% by mass, more preferably 80% by mass, and even more preferably 75% by mass.

[0036] (Polyvinyl butyral resin (B)) The liquid ink composition of the present invention contains a polyvinyl butyral resin (B) in order to improve dispersibility and adhesion. The polyvinyl butyral resin (B) is composed only of carbon atoms, hydrogen atoms, and oxygen atoms, and therefore can reduce the risk of environmental pollution over the life cycle of products such as packages that use the polyvinyl butyral resin (B).

[0037] The polyvinyl butyral resin (B) is not particularly limited and any known resin can be used. Generally, a reaction product obtained by acetalizing polyvinyl alcohol with butyral aldehyde through a known reaction can be used. The weight-average molecular weight of the polyvinyl butyral resin (B) is preferably 5,000 to 60,000, more preferably 6,000 to 50,000, and even more preferably 7,000 to 40,000. By setting the weight-average molecular weight of the polyvinyl butyral resin (B) within the above range, an ink with an excellent balance of fluidity and dispersibility can be obtained.

[0038] The glass transition temperature (hereinafter sometimes referred to as Tg) of the polyvinyl butyral resin (B) is preferably in the range of 50° C. to 120° C., more preferably in the range of 55° C. to 115° C., and more preferably in the range of 60 to 110° C. In the present invention, the glass transition temperature is obtained by measurement with a differential scanning calorimeter.

[0039] The hydroxyl group content of the polyvinyl butyral resin (B) is preferably in the range of 10% to 30% by mass, more preferably 15 to 25% by mass. By adjusting the hydroxyl group content of the polyvinyl butyral resin (B) to the above range, an ink with an excellent balance of fluidity and dispersibility can be obtained. Furthermore, the acetyl group content of the polyvinyl butyral resin (B) is preferably 10% by mass or less, more preferably 8% by mass or less. By adjusting the acetyl group content of the polyvinyl butyral resin (B) to the above range, an ink with an excellent balance of fluidity and dispersibility can be obtained. Furthermore, the acetalization degree of the polyvinyl butyral resin (B) is preferably 60 to 90% by mass, more preferably 65 to 85% by mass.

[0040] The content of polyvinyl butyral resin (B) (solid content of polyvinyl butyral resin (B)) is preferably 0.1% to 5% by mass, more preferably 0.1% to 4.0% by mass, and most preferably 0.2% to 3.0% by mass, relative to 100% by mass of the liquid ink composition. Adding a total of 0.1% by mass or more of polyvinyl butyral resin (B) tends to maintain the adhesion and transferability of the ink film, while keeping the total content 5% by mass or less can maintain the lamination strength of the ink. Furthermore, the lower limit of the solids weight ratio in the ink is preferably 0.1% by mass, more preferably 0.2% by mass, and most preferably 0.3% by mass. Furthermore, the upper limit of the solids weight ratio in the ink is preferably 16% by mass, more preferably 13% by mass, and most preferably 10% by mass. In order to obtain the effects of the present invention, the total mass of the polyurethane resin (A) and the polyvinyl butyral resin (B) is preferably 80 mass% or more, more preferably 85 mass% or more, even more preferably 90 mass% or more, and still more preferably 95 mass% or more, based on the total mass of the resins.

[0041] (Other Resins) In addition to the polyurethane resin (A) and the polyvinyl butyral resin (B), the liquid ink composition of the present invention may contain other resins that can be used in combination in the technical field of liquid inks. The resin may be a binder resin or a dispersion resin, but is preferably added as a binder resin. Examples of resins that can be used in combination include ethylene-vinyl acetate copolymer resins, vinyl acetate resins, polyamide resins, acrylic resins, polyester resins, alkyd resins, rosin-based resins, rosin-modified maleic acid resins, ketone resins, cyclized rubbers, petroleum resins, cellulose-based resins, and polyurethane resins (A) other than polyurethane resin (A). Among these, it is preferable to contain at least one resin selected from cellulose-based resins, polyester resins, acrylic resins, polyamide resins, and rosin-modified maleic acid resins, as this can improve blocking resistance and resolubility. Furthermore, from the perspective of reducing environmental impact, it is preferable that the liquid ink composition of the present invention does not contain a chlorine-based resin. These resins can be used alone or in combination. The content of the co-used resin is preferably 0.1% by mass to 25% by mass, and more preferably 2% by mass to 15% by mass, based on the total mass of the ink.

[0042] (Cellulose-Based Resins) Examples of cellulose-based resins include cellulose acetate propionate, cellulose acetate butyrate, and other cellulose ester resins, nitrocellulose (also known as soluble cellulose), hydroxyalkyl cellulose, and carboxyalkyl cellulose. The cellulose ester resin preferably has an alkyl group, such as a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a pentyl group, or a hexyl group. The alkyl group may further have a substituent. Of the above, cellulose acetate propionate, cellulose acetate butyrate, and nitrocellulose are preferred. The molecular weight is preferably a weight-average molecular weight of 5,000 to 200,000, more preferably 10,000 to 50,000. Furthermore, those having a glass transition temperature of 120°C to 180°C are preferred. When used in combination with the polyurethane resin (A) of the present invention, improved blocking resistance, scratch resistance, and other ink film properties can be expected. Nitrocellulose (nitrocellulose) is preferably obtained as a nitric acid ester by reacting natural cellulose with nitric acid to replace three hydroxyl groups in the six-membered ring of the anhydroglucopyranose group in the natural cellulose with nitric acid groups.

[0043] (Rosin-modified maleic acid resin) Rosin-modified maleic acid resin is an alkyd resin obtained by reacting a polyhydric alcohol such as glycerin, pentaerythritol, or ethylene glycol with an adduct of rosin and maleic acid obtained by Diels-Alder reaction. The acid value is determined by the blending ratio of the polyhydric alcohol reacted with the adduct of rosin and maleic acid and the degree of esterification. In addition to the polyhydric alcohol, a polybasic acid may also be used in combination to form a structure in which a long-chain alkyd resin is bonded to the rosin skeleton.

[0044] Examples of polyhydric alcohols to be reacted with the adduct of rosin and maleic acid include ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, trimethylolpropane, glycerin, pentaerythritol, sorbitol, etc. Examples of polybasic acids to be used together with these polyhydric alcohols as raw materials for alkyd resins include phthalic anhydride, terephthalic acid, isophthalic acid, adipic acid, maleic acid, itaconic acid, succinic acid, sebacic acid, etc.

[0045] Furthermore, for example, a compound having a carbon-carbon unsaturated double bond such as maleic acid may be used as a raw material for the alkyd resin, and a styrene-based monomer may be reacted with this to produce a rosin-modified styrene-maleic acid resin, which is also included in the rosin-modified maleic acid resin.

[0046] (Silica) The liquid ink composition of the present invention contains 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.

[0047] The preferred particle size distribution of the silica is determined using a volume-based particle size distribution measured using a laser diffraction particle size distribution analyzer. The cumulative 90% particle size (D90) of the volume-based particle size distribution of the 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 size (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 size (D50) of the volume-based particle size distribution of the silica is preferably 1 μm or more, more preferably 32 μm or more, and even more preferably 3 μm or more. The cumulative 50% particle size (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 size (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 size (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.

[0048] The particle size distribution of the silica, based on volume, preferably has a cumulative 50% particle diameter (D50) of 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 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 with silica particles of a size equal to or greater than this thickness will have excellent blocking resistance. Furthermore, the index (D90-D10) / D50 represents the uniformity of size per particle diameter; a smaller value indicates less variation 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.

[0049] The silica content is preferably 0.1% by mass to 5.0% by mass, more preferably 0.5% by mass to 4.5% by mass, and most preferably 1.0% by mass to 4.0% by mass, based on the total solid content (ink solid content) of the liquid ink composition of the present invention.

[0050] (Wax) The liquid ink composition of the present invention contains a wax. The wax may be any wax that is commonly used in gravure inks or flexographic inks, such as hydrocarbon waxes and amide waxes, and is not particularly limited. Examples of hydrocarbon waxes include polyethylene wax, Fischer-Tropsch wax, paraffin wax, microcrystalline wax, and polypropylene wax. Of these, hydrocarbon waxes including polyethylene wax and / or Fischer-Tropsch wax are preferred. These waxes may be used alone or in combination.

[0051] As the amide wax, fatty acid amide wax (sometimes referred to as fatty acid amide wax) is preferred. Examples of fatty acid amides (sometimes referred to as fatty acid amides; hereinafter, "amide" may also be referred to as "amide") include palmitic acid amide, stearic acid amide, ethylene bisoleic acid amide, hexamethylene bisoleic acid amide, and erucic acid amide. These may be used alone or in combination of two or more.

[0052] The wax is preferably contained in an amount of 0.05% to 2.0% by mass, based on the total solid content (ink solids) of the liquid ink composition of the present invention. A content of 0.1% to 1.5% by mass is more preferred, and a content of 0.2% to 1.0% by mass is most preferred. In particular, when a hydrocarbon wax is added, it is preferably contained in an amount of 0.05% to 2.0% by mass, based on the total solid content (ink solids) of the liquid ink composition of the present invention. A content of 0.1% to 1.5% by mass is more preferred, and a content of 0.2% to 1.0% by mass is most preferred. In particular, when an amide wax is added, it is preferably contained in an amount of 0.05% to 2.0% by mass, based on the total solid content (ink solids) of the liquid ink composition of the present invention. A content of 0.1% to 1.5% by mass is more preferred, and a content of 0.2% to 1.0% by mass is most preferred.

[0053] Of the waxes, fatty acid amide waxes are preferred.

[0054] The silica and wax are used in combination, and a liquid ink composition with superior blocking resistance can be obtained by using them in such a manner that the mass ratio of silica:wax is in the range of 50:50 to 95:5. The mass ratio of silica:wax is preferably in the range of 55:45 to 95:5, and most preferably in the range of 60:40 to 90:10.

[0055] (Pigment) The pigment used in the liquid ink composition of the present invention may be either a colored pigment or a white pigment. The pigment is not particularly limited, and examples thereof include inorganic and organic pigments commonly used in inks, paints, and recording materials. To particularly demonstrate the excellent effect of the present invention of improving storage stability, the pigment is preferably an organic pigment. Examples of organic pigments include soluble azo pigments, insoluble azo pigments, azo pigments, phthalocyanine pigments, halogenated phthalocyanine pigments, anthraquinone pigments, anthanthrone pigments, dianthraquinonyl pigments, anthrapyrimidine pigments, perylene pigments, perinone pigments, quinacridone pigments, thioindigo pigments, dioxazine pigments, isoindolinone pigments, quinophthalone pigments, azomethine azo pigments, flavanthrone pigments, diketopyrrolopyrrole pigments, isoindoline pigments, indanthrone pigments, and carbon black pigments. Other examples include carmine 6B, lake red C, permanent red 2B, disazo yellow, pyrazolone orange, carmine FB, cromophtal yellow, cromophtal red, phthalocyanine blue, phthalocyanine green, dioxazine violet, quinacridone magenta, quinacridone red, indanthrone blue, pyrimidine yellow, thioindigo bordeaux, thioindigo magenta, perylene red, perinone orange, isoindolinone yellow, aniline black, diketopyrrolopyrrole red, and daylight fluorescent pigments. Both non-acid-treated and acid-treated pigments can be used. Specific examples of preferred organic pigments are listed below.

[0056] Examples of black pigments include C.I. Pigment Black 1, C.I. Pigment Black 6, C.I. Pigment Black 7, C.I. Pigment Black 9, and C.I. Pigment Black 20.

[0057] Examples of indigo pigments include C.I. Pigment Blue 15, C.I. Pigment Blue 15:1, C.I. Pigment Blue 15:2, C.I. Pigment Blue 15:3, C.I. Pigment Blue 15:4, C.I. Pigment Blue 15:5, C.I. Pigment Blue 15:6, C.I. Pigment Blue 16, C.I. Pigment Blue 17:1, C.I. Pigment Blue 22, C.I. Pigment Blue 24:1, C.I. Pigment Blue 25, C.I. Pigment Blue 26, C.I. Pigment Blue 60, C.I. Pigment Blue 61, C.I. Pigment Blue 62, C.I. Pigment Blue 63, C.I. Examples of pigments that can be used include C.I. Pigment Blue 64, C.I. Pigment Blue 75, C.I. Pigment Blue 79, and C.I. Pigment Blue 80.

[0058] Examples of green pigments include C.I. Pigment Green 1, C.I. Pigment Green 4, C.I. Pigment Green 7, C.I. Pigment Green 8, C.I. Pigment Green 10, and C.I. Pigment Green 36.

[0059] Examples of red pigments include C.I. Pigment Red 1, C.I. Pigment Red 2, C.I. Pigment Red 3, C.I. Pigment Red 4, C.I. Pigment Red 5, C.I. Pigment Red 6, C.I. Pigment Red 7, C.I. Pigment Red 8, C.I. Pigment Red 9, C.I. Pigment Red 10, C.I. Pigment Red 11, C.I. Pigment Red 12, C.I. Pigment Red 15, C.I. Pigment Red 16, C.I. Pigment Red 17, C.I. Pigment Red 18, C.I. Pigment Red 19, C.I. Pigment Red 20, C.I. Pigment Red 21, C.I. C.I. Pigment Red 22, C.I. Pigment Red 23, C.I. Pigment Red 31, C.I. Pigment Red 32, C.I. Pigment Red 38, C.I. Pigment Red 41, C.I. Pigment Red 43, C.I. Pigment Red 46, C.I. Pigment Red 48, C.I. Pigment Red 48:1, C.I. Pigment Red 48:2, C.I. Pigment Red 48:3, C.I. Pigment Red 48:4, C.I. Pigment Red 48:5, C.I. Pigment Red 48:6, C.I. Pigment Red 49, C.I. Pigment Red 49:1, C.I. Pigment Red 49:2, C.I. Pigment Red 49:3, C.I. Pigment Red 52, C.I. Pigment Red 52:1, C.I. Pigment Red 52:2, C.I. Pigment Red 53, C.I. Pigment Red 53:1, C.I. Pigment Red 53:2, C.I. Pigment Red 53:3, C.I. Pigment Red 54, C.I. Pigment Red 57, C.I. Pigment Red 57:1, C.I. Pigment Red 58, C.I. Pigment Red 58:1, C.I. Pigment Red 58:2, C.I. Pigment Red 58:3, C.I. Pigment Red 58:4, C.I. Pigment Red 60:1, C.I. Pigment Red 63, C.I. Pigment Red 63:1, C.I. Pigment Red 63:2, C.I. Pigment Red 63:3, C.I. Pigment Red 64:1, C.I. Pigment Red 68, C.I. Pigment Red 68, C.I. Pigment Red 81:1, C.I. Pigment Red 83,C.I. Pigment Red 88, C.I. Pigment Red 89, C.I. Pigment Red 95, C.I. Pigment Red 112, C.I. Pigment Red 114, C.I. Pigment Red 119, C.I. Pigment Red 122, C.I. Pigment Red 123, C.I. Pigment Red 136, C.I. Pigment Red 144, C.I. Pigment Red 146, C.I. Pigment Red 147, C.I. Pigment Red 149, C.I. Pigment Red 150, C.I. Pigment Red 164, C.I. Pigment Red 166, C.I. Pigment Red 168, C.I. Pigment Red 169, C.I. Pigment Red 170, C.I. Pigment Red 171, C.I. Pigment Red 172, C.I. Pigment Red 175, C.I. Pigment Red 176, C.I. Pigment Red 177, C.I. Pigment Red 178, C.I. Pigment Red 179, C.I. Pigment Red 180, C.I. Pigment Red 181, C.I. Pigment Red 182, C.I. Pigment Red 183, C.I. Pigment Red 184, C.I. Pigment Red 185, C.I. Pigment Red 187, C.I. Pigment Red 188, C.I. Pigment Red 190, C.I. Pigment Red 192, C.I. Pigment Red 193, C.I. Pigment Red 194, C.I. Pigment Red 200, C.I. Pigment Red 202, C.I. Pigment Red 206, C.I. Pigment Red 207, C.I. Pigment Red 208, C.I. Pigment Red 209, C.I. Pigment Red 210, C.I. Pigment Red 211, C.I. Pigment Red 213, C.I. Pigment Red 214, C.I. Pigment Red 216, C.I. Pigment Red 215, C.I. Pigment Red 216, C.I. Pigment Red 220, C.I. Pigment Red 221, C.I. Pigment Red 223, C.I. Pigment Red 224, C.I. Pigment Red 226, C.I. Pigment Red 237, C.I. Pigment Red 238, C.I. Pigment Red 239, C.I. Pigment Red 240, C.I. Pigment Red 242, C.I. Pigment Red 245,C.I. Pigment Red 247, C.I. Pigment Red 248, C.I. Pigment Red 251, C.I. Pigment Red 253, C.I. Pigment Red 254, C.I. Pigment Red 255, C.I. Pigment Red 256, C.I. Pigment Red 257, C.I. Pigment Red 258, C.I. Pigment Red 260, C.I. Pigment Red 262, C.I. Pigment Red 263, C.I. Pigment Red 264, C.I. Pigment Red 266, C.I. Pigment Red 268, C.I. Pigment Red 269, C.I. Pigment Red 270, C.I. Examples of suitable pigments include C.I. Pigment Red 271, C.I. Pigment Red 272, and C.I. Pigment Red 279.

[0060] Examples of purple pigments include C.I. Pigment Violet 1, C.I. Pigment Violet 2, C.I. Pigment Violet 3, C.I. Pigment Violet 3:1, C.I. Pigment Violet 3:3, C.I. Pigment Violet 5:1, C.I. Pigment Violet 13, C.I. Pigment Violet 19 (γ type, β type), C.I. Pigment Violet 23, C.I. Pigment Violet 25, C.I. Pigment Violet 27, C.I. Pigment Violet 29, C.I. Pigment Violet 31, C.I. Pigment Violet 32, C.I. Pigment Violet 36, C.I. Pigment Violet 37, C.I. Examples of suitable pigments include C.I. Pigment Violet 38, C.I. Pigment Violet 42, C.I. Pigment Violet 50, and the like.

[0061] Examples of yellow pigments include C.I. Pigment Yellow 1, C.I. Pigment Yellow 3, C.I. Pigment Yellow 12, C.I. Pigment Yellow 13, C.I. Pigment Yellow 14, Pigment Yellow 17, C.I. Pigment Yellow 24, C.I. Pigment Yellow 42, C.I. Pigment Yellow 55, C.I. Pigment Yellow 62, C.I. Pigment Yellow 65, C.I. Pigment Yellow 74, C.I. Pigment Yellow 83, C.I. Pigment Yellow 86, C.I. Pigment Yellow 93, C.I. Pigment Yellow 94, C.I. Pigment Yellow 95, C.I. Pigment Yellow 109, C.I. Pigment Yellow 110, C.I. Pigment Yellow 117, C.I. Pigment Yellow 120, Pigment Yellow 125, C.I. Pigment Yellow 128, C.I. Pigment Yellow 129, C.I. Pigment Yellow 137, C.I. Pigment Yellow 138, C.I. Pigment Yellow 139, C.I. Pigment Yellow 147, C.I. Pigment Yellow 148, C.I. Pigment Yellow 150, C.I. Pigment Yellow 151, C.I. Pigment Yellow 153, C.I. Pigment Yellow 154, C.I. Pigment Yellow 155, C.I. Pigment Yellow 166, C.I. Pigment Yellow 168, C.I. Examples of pigments that can be used include C.I. Pigment Yellow 174, C.I. Pigment Yellow 180, C.I. Pigment Yellow 185, and C.I. Pigment Yellow 213.

[0062] Examples of orange pigments include C.I. Pigment Orange 5, C.I. Pigment Orange 13, C.I. Pigment Orange 16, C.I. Pigment Orange 34, C.I. Pigment Orange 36, C.I. Pigment Orange 37, C.I. Pigment Orange 38, C.I. Pigment Orange 43, C.I. Pigment Orange 51, C.I. Pigment Orange 55, C.I. Pigment Orange 59, C.I. Pigment Orange 61, C.I. Pigment Orange 64, C.I. Pigment Orange 71, and C.I. Pigment Orange 74.

[0063] Examples of brown pigments include C.I. Pigment Brown 23, C.I. Pigment Brown 25, and C.I. Pigment Brown 26.

[0064] Among them, preferred pigments include C.I. Pigment Black 7 as a black pigment, C.I. Pigment Blue 15, C.I. Pigment Blue 15:1, C.I. Pigment Blue 15:2, C.I. Pigment Blue 15:3, C.I. Pigment Blue 15:4, C.I. Pigment Blue 15:6 as indigo pigments, C.I. Pigment Green 7 as a green pigment, and C.I. Pigment Red 57:1, C.I. Pigment Red 48:1, C.I. Pigment Red 48:2, C.I. Pigment Red 48:3, C.I. Pigment Red 146, C.I. Pigment Red 242, C.I. Pigment Red 185, C.I. Examples of pigments that can be used include C.I. Pigment Red 122, C.I. Pigment Red 178, C.I. Pigment Red 149, C.I. Pigment Red 144, C.I. Pigment Red 166, purple pigments include C.I. Pigment Violet 23 and C.I. Pigment Violet 37, yellow pigments include C.I. Pigment Yellow 83, C.I. Pigment Yellow 14, C.I. Pigment Yellow 180, and C.I. Pigment Yellow 139, and orange pigments include C.I. Pigment Orange 38, C.I. Pigment Orange 13, C.I. Pigment Orange 34, and C.I. Pigment Orange 64. It is preferable to use at least one or more pigments selected from these groups.

[0065] Examples of inorganic pigments include white inorganic pigments such as titanium oxide, zinc oxide, zinc sulfide, barium sulfate, calcium carbonate, chromium oxide, silica, lithopone, antimony white, and gypsum. Among the inorganic pigments, titanium oxide is particularly preferred. Titanium oxide exhibits a white color and is preferred in terms of coloring power, hiding power, chemical resistance, and weather resistance. From the viewpoint of printing performance, titanium oxide that has been treated with silica and / or alumina is preferred.

[0066] Examples of inorganic pigments other than white include carbon black, aluminum particles, mica, bronze powder, chrome vermilion, yellow lead, cadmium yellow, cadmium red, ultramarine, Prussian blue, red iron oxide, yellow iron oxide, iron black, and zircon. Aluminum is in powder or paste form, but it is preferably used in paste form from the standpoints of handleability and safety, and whether leafing or non-leafing aluminum is used is selected appropriately from the standpoints of brightness and concentration.

[0067] The pigment is preferably contained in an amount sufficient to ensure the concentration and coloring strength of the liquid ink composition, i.e., 1 to 60% by mass of the total mass of the ink, or 10 to 90% by mass in terms of the weight ratio of solids in the ink. The colorants may be used alone or in combination of two or more.

[0068] The present invention may further contain, as required, extender pigments, pigment dispersants, leveling agents, antifoaming agents, waxes, plasticizers, infrared absorbers, ultraviolet absorbers, aromatics, flame retardants, and the like.

[0069] To stably disperse the pigment in an organic solvent, a resin alone can be used, but a dispersant can also be used to further stabilize the pigment. Examples of dispersants include anionic, nonionic, cationic, and amphoteric surfactants. Examples include comb-structured polymers in which polyethyleneimine is polyester-added, or alkylamine derivatives of α-olefin maleic acid polymers. Specific examples include the Solsperse series (ZENECA), the Ajisper series (Ajinomoto), and the Homogenol series (Kao). The BYK series (BYK-Chemie) and the EFKA series (EFKA) can also be used. From the perspective of ink storage stability, the dispersant content in the ink is preferably 0.05% by mass or more of the total ink mass, and from the perspective of lamination suitability, it is preferably 5% by mass or less, more preferably 0.1 to 2% by mass.

[0070] (Organic Solvent) Various organic solvents can be used as the organic solvent for use in the liquid ink composition of the present invention, and examples thereof include aromatic organic solvents such as toluene and xylene, ketone-based organic solvents such as acetone, methyl ethyl ketone and methyl isobutyl ketone, ester-based organic solvents such as ethyl acetate, n-propyl acetate, butyl acetate and propylene glycol monomethyl ether acetate, and alcohol-based organic solvents such as n-propanol, isopropanol, n-butanol and propylene glycol monomethyl ether, and these can be used alone or in a mixture of two or more. In recent years, from the viewpoint of the working environment, it has been preferable not to use aromatic organic solvents such as toluene and xylene or ketone-based organic solvents.

[0071] The organic solvent preferably contains the ester-based organic solvent and the alcohol-based organic solvent, and the mass ratio thereof is preferably set to ester-based organic solvent:alcohol-based organic solvent = 1:1 to 9:1. When the mass ratio in the organic solvent is within this range, the ink can have excellent printability and blocking resistance. The mass ratio is more preferably 2:1 to 9:1, and even more preferably 2:1 to 8:1.

[0072] (Water) The liquid ink composition of the present invention may contain water as a volatile component in addition to the organic solvent. The water content is preferably less than 10% by mass of the total ink composition. The addition of water can control the drying properties of the ink, and in gravure printing in particular, it can beautifully reproduce the gradation areas characterized by low ink transfer. Furthermore, a water content of 1% to 5% by mass of the total ink composition is particularly preferred because it improves printability. The addition of water in this manner also makes it possible to reduce the amount of organic solvent used. Water may be added to the organic solvent in advance to form a hydrous organic solvent, or a specific amount of water may be added separately. The liquid ink composition of the present invention can be a one-component type that does not use a curing agent such as an isocyanate curing agent, or a two-component type that does use a curing agent, and can provide a liquid ink composition with excellent ink dispersibility and flowability.

[0073] (Method for producing liquid ink composition) The liquid ink composition of the present invention can be produced by dissolving and / or dispersing a resin, a pigment, etc. in an organic solvent. Specifically, a pigment dispersion is produced by dispersing the pigment in an organic solvent using a polyvinyl butyral resin (B), and the ink can be produced by blending other compounds, resins, etc. with the resulting pigment dispersion. The pigment may be dispersed using a polyurethane resin (A), another resin, or a dispersant, but it is preferable to disperse the pigment using a polyvinyl butyral resin (B).

[0074] 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 devices such as a roller mill, ball mill, pebble mill, attritor, sand mill, etc. can be used. If air bubbles or unexpectedly large particles are present in the ink, they are preferably removed by filtration or the like, as they will degrade the quality of the printed material. Conventional filters can be used.

[0075] The viscosity of the ink produced by the above method is preferably in the range of 10 mPa·s or more from the viewpoint of preventing sedimentation of the pigment and adequately dispersing it, and 1000 mPa·s or less from the viewpoint of workability during ink production and printing. The above viscosity is measured at 25°C using a Tokimec B-type viscometer. The viscosity of the ink can be adjusted by appropriately selecting the types and amounts of raw materials used, such as the polyurethane resin (A), polyvinyl butyral resin (B), pigment, organic solvent, etc. The viscosity of the ink can also be adjusted by adjusting the particle size and particle size distribution of the pigment in the ink.

[0076] The hues of the liquid ink composition of the present invention, depending on the type of pigment used, include five process basic colors: yellow, crimson, indigo, black, and white, and three process gamut colors: red (orange), grass (green), and purple. Furthermore, transparent yellow, peony, vermilion, brown, gold, silver, pearl, and a nearly transparent medium (containing an extender pigment as needed) for adjusting color density are prepared as base colors. For boil retort inks, the pigments are appropriately selected taking into consideration their migration properties and heat resistance.

[0077] (Printed Matter) The liquid ink composition of the present invention can be printed to produce a printed matter. Printing methods using known printing plates, such as gravure printing and flexographic printing, are possible, with gravure printing being particularly preferred. Known cylinders, such as engraved and etching types, are used for gravure printing. The layer on which a desired design is formed using the liquid ink composition of the present invention is referred to as a printed layer. This printed layer may be a single layer, or there may be multiple printed layers. When there are multiple printed layers, the liquid ink compositions used for each printed layer may be the same, or may be the same composition with only the colorant being different, or may be different compositions. When there are multiple printed layers, the printed matter may have, for example, a first printed layer formed from a color liquid ink composition, a second white printed layer formed from a white liquid ink, and a third white printed layer, in this order. The first printed layer can form a pattern using a pigment, and the second white printed layer formed with white liquid ink and the third printed layer can be used as a background for the pattern. If the second or third printed layer is an overprint varnish, it does not need to contain a colorant such as a pigment.

[0078] The base ink is diluted with a diluting solvent to a viscosity and concentration suitable for gravure printing or flexographic printing, and is supplied to each printing unit either alone or in a mixture for printing.

[0079] (Laminated Laminate) The laminated body of the present invention may have the following configuration: (1) substrate / adhesive layer / printed layer / substrate; (2) substrate / adhesive layer / substrate / printed layer / adhesive layer / substrate; (3) substrate / adhesive layer / first printed layer / second printed layer / substrate; (4) substrate / adhesive layer / barrier layer / printed layer / adhesive layer / substrate; (5) substrate / printed layer / adhesive layer / substrate. The laminated body may further include, but is not limited to, an additional substrate. When multiple substrates are included, the substrates may be the same or different. The substrate may also be a substrate such as a sealable sealant film or a multilayer film including a sealant layer formed by a heat sealing agent, and the sealable layer is referred to as a sealant layer. The multiple adhesive layers may have the same composition or different compositions. Furthermore, an anchor coat layer may be sandwiched between the adhesive layers to improve the adhesive strength. The above configurations (1) to (5) illustrate examples of laminated bodies in which layers between the substrates are laminated via an adhesive layer. However, in another embodiment of the present disclosure, an extrusion lamination configuration may be used in which a molten resin is extruded without providing an adhesive layer. In the case of extrusion lamination, polyethylene or polypropylene is preferably used as the extrusion resin. In this case, an imine-based, butadiene-based, or isocyanate-based anchor coat layer may be provided on the printing layer, and a resin may be melt-extruded onto the anchor coat layer.

[0080] The liquid ink composition of the present invention is useful for printing on a wide variety of substrates, from general-purpose films to various high-performance films. Usable plastic films are not particularly limited, and examples include polyamide resins such as Ny6, nylon 66, and nylon 46; polyester resins such as polyethylene phthalate (PET), polyethylene naphthalate, polytrimethylene terephthalate, polytrimethylene naphthalate, polybutylene terephthalate, and polybutylene naphthalate; biodegradable resins such as polyhydroxycarboxylic acids such as polylactic acid, aliphatic polyester resins such as poly(ethylene succinate) and poly(butylene succinate); thermoplastic resins such as polyolefin resins such as polypropylene (PP) and polyethylene, polyimide resins, polyarylate resins, and mixtures thereof; various high-performance films coated with inorganic or organic barrier coating materials on their surfaces; and laminates thereof. Among these, films made of polyester, polyamide, polyethylene, and polypropylene are particularly preferred. These films may be unstretched or stretched, and their manufacturing methods are not limited. The base film may be a multilayer film produced by co-extrusion of the resins of each layer, or a multilayer sealant film having a sealant layer as the outermost layer of the multilayer film. The thickness of the base film is not particularly limited, but is usually in the range of 1 to 500 μm.

[0081] The substrate may be formed from a biomass polyolefin. The biomass polyolefin refers to a polyolefin resin using a plant-derived olefin as a raw material monomer. The raw material monomer may contain a petroleum-derived monomer, and may not contain 100% plant-derived monomers. Commercially available biomass polyolefins may also be used. Examples of commercially available products include SGM9450F, SLL118, SLL118 / 21, SLL218, SLL318, SLH118, SLH218, and SLH0820 manufactured by Braskem.

[0082] The substrate used in the laminate of the present invention may be a substrate having a vapor-deposited layer made of an inorganic substance and / or inorganic oxide provided on the above-mentioned resin film. By using a substrate having such a vapor-deposited layer, barrier properties can be imparted to the laminate of the present invention. The vapor-deposited layer can be formed by a known method using a known inorganic substance or inorganic oxide, and its composition and formation method are not particularly limited. The laminate may have two or more vapor-deposited layers, which may have the same composition or different compositions.

[0083] The vapor-deposited layer may be, for example, a vapor-deposited film of an inorganic substance or inorganic oxide such as silicon (Si), aluminum (Al), magnesium (Mg), calcium (Ca), potassium (K), tin (Sn), sodium (Na), boron (B), titanium (Ti), lead (Pb), zirconium (Zr), yttrium (Y), etc. Vapor-deposited films of inorganic oxides such as silicon oxide and aluminum oxide are transparent.

[0084] The inorganic oxides are expressed as MOx (where M represents an inorganic element), such as SiOx and AlOx. The value of x can range from 0 to 2 for silicon (Si), 0 to 1.5 for aluminum (Al), 0 to 1.5 for magnesium (Mg), 0 to 1 for calcium (Ca), 0 to 0.5 for potassium (K), 0 to 2 for tin (Sn), 0 to 0.5 for sodium (Na), 0 to 1.5 for boron (B), 0 to 1.5 for titanium (Ti), 0 to 2 for lead (Pb), 0 to 1 for zirconium (Zr), and 0 to 1.5 for yttrium (Y). In the above, when x = 0, the material is a completely inorganic element (pure substance) and is not transparent. When the value of x is at the upper limit of the range, the material is completely oxidized. Silicon (Si) or aluminum (Al) is preferably used as the vapor deposition layer, and silicon (Si) having an x ​​value in the range of 1.0 to 2.0 and aluminum (Al) having an x ​​value in the range of 0.5 to 1.5 can be used.

[0085] The vapor deposition layer can be formed on the surface of the substrate or the like by a physical vapor deposition method (PVD method) such as vacuum deposition, sputtering, or ion plating, or a chemical vapor deposition method (CVD method) such as plasma chemical vapor deposition, thermal chemical vapor deposition, or photochemical vapor deposition.

[0086] The thickness of the vapor-deposited layer is not particularly limited as long as the vapor-deposited layer alone can exhibit a certain level of gas barrier function. The preferred thickness range varies depending on the type of metal or metal oxide to be vapor-deposited, but is preferably 0.05 to 70 nm, more preferably 0.1 to 70 nm, still more preferably 3 to 70 nm, and even more preferably 5 to 60 nm.

[0087] Examples of the metal-deposited film include a VM-CPP film obtained by depositing a metal such as aluminum on a CPP film, and a VM-OPP film obtained by depositing a metal such as aluminum on an OPP film. Examples of the transparent deposited film include films obtained by depositing silica or alumina on an OPP film, PET film, nylon film, or the like. For the purpose of protecting the inorganic deposited layer of silica or alumina, a film with a coating applied to the deposited layer may also be used.

[0088] Paper can also be used as the substrate. Examples of papers that can be used include fine paper used for printing on packaging for cosmetics, beverages, pharmaceuticals, toys, equipment, etc., kraft paper, pure white roll paper, glassine paper, parchment paper, Manila cardboard, white cardboard, coated paper, art paper, construction paper, thin paper, cardboard, polyethylene-coated paper, various synthetic papers, and acid-resistant paper.

[0089] Furthermore, if the printing surface of the substrate is subjected to a corona discharge treatment, the adhesion to the substrate can be further improved, which is preferable.

[0090] (Lamination Method) The lamination method for producing the laminate of the present invention is not particularly limited, and examples thereof include dry lamination, wet lamination, non-solvent lamination, extrusion lamination, etc. In this case, the layer located between the substrates is called an adhesive layer.

[0091] Examples of adhesives used in the dry lamination include solvent-based two-component curing adhesives, etc. A "solvent-based" adhesive refers to a form used in a so-called dry lamination method, in which the adhesive is applied to a substrate, heated in an oven or the like to volatilize the organic solvent in the coating, and then bonded to another substrate, and includes a polyisocyanate composition, a polyol composition, and an organic solvent capable of dissolving (diluting) them.

[0092] In the two-component curing adhesive, in consideration of the creation of a sustainable recycling-based society (sustainability), it is preferable to use plant-derived materials (biomass materials) as raw materials for the polyisocyanate composition or polyol composition. By appropriately using biomass materials, the environmental impact can be reduced. Examples of biomass materials include castor oil-based polyols such as castor oil, dehydrated castor oil, hydrogenated castor oil (a hydrogenated castor oil), and 5 to 50 mol alkylene oxide adducts of castor oil; aliphatic polybasic acids such as succinic acid, succinic anhydride, glutaric acid, adipic acid, azelaic acid, sebacic acid, and itaconic acid; alkyl esters of these acids; and dimer acids.

[0093] Commercially available adhesives using biomass raw materials can also be used, such as those listed by the Japan Organics Resources Association, including DIC Dry BM (manufactured by DIC Corporation) and Takenate BM (manufactured by Mitsui Chemicals, Inc.).

[0094] The weight of the adhesive layer after drying is 0.1 to 10 g / m ２ It is preferable that the density is 1 to 6 g / m ２ More preferably, it is 2 to 5 g / m ２The thickness of the adhesive layer is preferably 0.1 to 10 μm, more preferably 1 to 7 μm, and even more preferably 2 to 5 μm.

[0095] Although various pressure-sensitive adhesives can be used for the adhesive layer, it is preferable to use a pressure-sensitive adhesive. Examples of such pressure-sensitive adhesives include rubber-based adhesives obtained by dissolving polyisobutylene rubber, butyl rubber, or mixtures thereof in organic solvents such as benzene, toluene, xylene, and hexane, or those rubber-based adhesives blended with tackifiers such as abiethylene acid rosin ester, terpene-phenol copolymer, and terpene-indene copolymer, and acrylic-based adhesives obtained by dissolving an acrylic copolymer having a glass transition temperature of −20° C. or lower, such as a 2-ethylhexyl acrylate-n-butyl acrylate copolymer or a 2-ethylhexyl acrylate-ethyl acrylate-methyl methacrylate copolymer, in an organic solvent.

[0096] When a material having gas barrier properties is used as the adhesive or the anchor coating agent described below, a laminate film having particularly excellent gas barrier properties can be obtained. 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 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.

[0097] The adhesive layer can also be formed from a thermoplastic resin, and the method for forming the adhesive layer can be a conventionally known method, such as a melt extrusion lamination method or a sand lamination method. Examples of the thermoplastic resin that can be used for the adhesive layer include polyethylene resins such as low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), medium-density polyethylene (MDPE), and high-density polyethylene (HDPE), polypropylene resins such as propylene homopolymers, propylene-α-olefin random copolymers, and propylene-α-olefin block copolymers, norbornene polymers and hydrogenated products thereof, such as norbornene copolymers (COC) obtained by copolymerizing norbornene monomers with olefins such as ethylene, vinyl alicyclic hydrocarbon polymers, and cyclic conjugated diene polymers, and cyclic polyolefin resins such as ethylene homopolymers, propylene copolymers (COC), and propylene copolymers (COC) obtained by copolymerizing norbornene monomers with olefins such as ethylene. Examples of suitable elastomers include polyethylene-based elastomers such as ethylene-vinyl acetate copolymer (EVA) and ethylene-α-olefin copolymers, polypropylene-based elastomers, and butene-based elastomers; ethylene-based copolymers such as ethylene-methyl methacrylate copolymer (EMMA), ethylene-ethyl acrylate copolymer (EEA), ethylene-methyl acrylate (EMA) copolymer, ethylene-ethyl acrylate-maleic anhydride copolymer (E-EA-MAH), ethylene-acrylic acid copolymer (EAA), and ethylene-methacrylic acid copolymer (EMAA); and ionomers of ethylene-acrylic acid copolymers and ionomers of ethylene-methacrylic acid copolymers. Furthermore, in order to improve interlayer adhesion, acid-modified polyolefin-based resins obtained by modifying the above-mentioned polyolefin-based resins with unsaturated carboxylic acids such as acrylic acid, methacrylic acid, maleic acid, maleic anhydride, fumaric acid, and itaconic acid can also be used. In addition, resins obtained by graft polymerizing or copolymerizing unsaturated carboxylic acids, unsaturated carboxylic anhydrides, or ester monomers with polyolefin resins can also be used. These resins can be used alone or in combination of two or more. It is also preferable to use polyethylene-based resins that use the above-mentioned biomass-derived ethylene as a monomer unit.

[0098] When laminating an adhesive layer using extrusion lamination, an anchor coating layer may be formed by applying and drying an anchor coating agent to the surface of the layer to be laminated. Examples of anchor coating agents include anchor coating agents made of any resin with a heat resistance temperature of 135°C or higher, such as polybutadiene-based resins, urethane resins, polyisocyanate-polyether polyols, polyethyleneimine, vinyl-modified resins, epoxy resins, polyester resins, and alkyl titanates, as well as anchor coating agents obtained by diluting the above adhesives with organic solvents. Among these, polyethyleneimine-based anchor coating agents and anchor coating agents obtained by diluting the above adhesives with organic solvents are preferred. A silane coupling agent may also be used as an additive, and soluble nitrocellulose may also be used to enhance heat resistance.

[0099] (Packaging Material) The packaging material of the present invention preferably comprises a laminated laminate containing the liquid ink composition of the present invention. For example, the packaging material may be formed by arranging two sheets of the laminated laminate so that their sealant layers are in contact with each other and sealing them, or by folding a continuous (single) sheet of the laminated laminate so that the sealant layers are in contact with each other and sealing it, or by arranging the laminated laminate and a thermoplastic resin film so that the sealant layer of the laminated laminate is in contact with the thermoplastic resin film and sealing it. The sealing method is not particularly limited, and may be heat sealing or ultrasonic sealing, or any known method can be used. The packaging material can be suitably used as a package. Examples of such packages include packaging for food products such as Western confectionery, snacks, bread, Japanese confectionery, and seasonings; medical packaging for medicines, bandages, and syringes; and hygiene product packaging for dustcloths, masks, and brushes.

[0100] (Recycled Plastics) The laminate or packaging material of the present invention can also be processed directly using various known recycling plastic processing methods to produce recycled plastics. As an example of a specific embodiment, recycled plastics can be obtained by a production method including the steps of impregnating the laminate of the present invention in, for example, a desorption treatment liquid, separating the laminate into each substrate, recovering the recovered material, or crushing the laminate or packaging material of the present invention, melting and kneading the crushed film pieces, and pelletizing the melt-kneaded mixture.

[0101] The crusher used for crushing (pulverization) may be 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. The melt kneading method is particularly common. Examples of kneading devices include a tumbler, Henschel mixer, rotary mixer, super mixer, ribbon tumbler, and V-blender. The film is melt-kneaded using such a kneading device 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 they are or may be subjected to a compression volume reduction treatment with or without heating before being fed. In addition to these extruders, a Banbury mixer, roller, Ko-kneader, blast mill, Prabender Bloutograph, or the like may also be used, and these may be operated batchwise or continuously. Alternatively, the film may be used as a molding resin without being melt-kneaded, and melt-kneaded in the heating barrel of a molding machine.

[0102] The present invention will be explained in more detail with reference to examples. Hereinafter, "parts" and "%" are all based on mass. Measurement of weight-average molecular weight (polystyrene equivalent) by GPC (gel permeation chromatography) in the present invention was carried out using an HLC8220 system manufactured by Tosoh Corporation under the following conditions: Separation column: Four TSKgel GMHHR-N columns manufactured by Tosoh Corporation. Column temperature: 40°C. Mobile phase: tetrahydrofuran manufactured by Wako Pure Chemical Industries, Ltd. Flow rate: 1.0 ml / min. Sample concentration: 1.0 wt%. Sample injection volume: 100 microliters. Detector: differential refractometer. Viscosity was measured at 25°C using a B-type viscometer manufactured by Tokimec Inc.

[0103] (Synthesis Example 1: Polyurethane Resin (A) Solution P1) A four-necked flask equipped with a stirrer, thermometer, reflux condenser, and nitrogen gas inlet tube was charged with 227.36 parts of neopentyl glycol adipate diol (hydroxyl value: 56.1 mg KOH / g), 16.51 parts of polyethylene glycol (hydroxyl value: 280.5 mg KOH / g), and 45.91 parts of isophorone diisocyanate, and the mixture was reacted at 90 ° C. for 8 hours under a nitrogen stream to produce a urethane resin prepolymer having an isocyanate group content of 1.49% by mass. 193.18 parts of ethyl acetate was then added to the mixture to obtain a homogeneous solution of the urethane resin prepolymer. Next, the urethane resin prepolymer solution was added to a mixture of 9.52 parts of isophorone diamine, 0.70 parts of cyclohexylamine, 296.82 parts of ethyl acetate, and 210.0 parts of isopropyl alcohol, and the mixture was stirred and reacted at 45 ° C. for 5 hours to obtain a polyurethane resin (A) solution P1. The obtained polyurethane resin (A) solution P1 had a resin solids concentration of 30.0% by mass, an amine value of 3.00 mgKOH / g, and an Mw of the resin solids of 26,000.

[0104] (Synthesis Example 2: Polyurethane Resin (A) Solution P2) A four-necked flask equipped with a stirrer, thermometer, reflux condenser, and nitrogen gas inlet tube was charged with 212.34 parts of 2-methylpropanediol adipate diol (hydroxyl value: 56.1 mg KOH / g) and 23.62 parts of polypropylene glycol (hydroxyl value: 112.2 mg KOH / g) and 47.84 parts of isophorone diisocyanate, and the mixture was reacted at 90 ° C. for 7 hours under a nitrogen stream to produce a urethane resin prepolymer having an isocyanate group content of 2.52% by mass. 189.2 parts of ethyl acetate was then added to the mixture to obtain a homogeneous solution of the urethane resin prepolymer. Next, 15.73 parts of isophorone diamine, 0.47 parts of cyclohexylamine, 300.8 parts of ethyl acetate, and 210.0 parts of isopropyl alcohol were added to the urethane resin prepolymer solution, and the mixture was stirred and reacted at 45 ° C. for 5 hours to obtain a polyurethane resin (A) solution P2. The obtained polyurethane resin (A) solution P2 had a resin solids concentration of 30.0% by mass, an amine value of 3.60 mgKOH / g, and an Mw of the resin solids of 25,000.

[0105] (Synthesis Example 3: Polyurethane Resin (A) Solution P3) A four-necked flask equipped with a stirrer, thermometer, reflux condenser and nitrogen gas inlet tube was charged with 221.73 parts of neopentyl glycol sebacate (hydroxyl value: 56.1 mg KOH / g) and 54.53 parts of isophorone diisocyanate, and reacted for 8 hours at 90 ° C. under a nitrogen stream to produce a urethane prepolymer having an isocyanate group content of 4.04 mass%, and then 184.24 parts of ethyl acetate was added to this to obtain a homogeneous solution of urethane prepolymer. Next, the urethane prepolymer solution was added to a mixture of 22.50 parts of isophorone diamine, 1.14 parts of cyclohexylamine, 305.76 parts of ethyl acetate and 210.0 parts of isopropyl alcohol, and the mixture was stirred and reacted at 45 ° C. for 5 hours to obtain a polyurethane resin (A) solution P3. The obtained polyurethane resin (A) solution P3 had a resin solids concentration of 30.0 mass %, an amine value of 2.00 mgKOH / g, and an Mw of the resin solids of 27,000.

[0106] (Preparation of Polyvinyl Butyral Resin (B)) Polyvinyl butyral resin (B) (weight average molecular weight 10,000, hydroxyl group content 15% by mass, glass transition point 60°C, acetyl group content 8% by mass) obtained by reacting polyvinyl alcohol with butyral aldehyde was dissolved in n-propyl acetate to form a solution with a solid content of 15%, which was used as a polyvinyl butyral resin (B) solution.

[0107] (Preparation of Cellulose Resin Solution) 20 parts of cellulose acetate propionate CAP482-0.5 (manufactured by Eastman Chemical Co.) was added with 80 parts of a mixed solution of isopropyl alcohol / ethyl acetate (ratio: 40 / 40 by weight) and thoroughly mixed to prepare a cellulose ester (CAP) resin solution with a resin solids concentration of 20% by mass.

[0108] Example 1 A mixture of 9 parts by weight of polyurethane resin (A) solution P1 (30% solids), 1.5 parts by weight of polyvinyl butyral resin (B) (15% solids), 0.6 parts by weight of cellulose acetate propionate resin solution (20% solids), 0.5 parts by weight of silica (particle diameter 4 μm), 0.15 parts by weight of fatty acid amide solution (10% solids), 10 parts by weight of phthalocyanine blue pigment (FASTGEN Blue LA5380: manufactured by DIC Corporation), 45 parts by weight of ethyl acetate, and 2 parts by weight of water was kneaded using a Dynomill (manufactured by Willy & Bachofenon) to prepare the liquid ink of Example 1. The amounts of various solvents added later were adjusted so that the amounts contained in the resin solution and the amounts added later were equal to the amounts listed above.

[0109] (Examples 2 to 10 and Comparative Examples 1 and 2) Using the formulations shown in Tables 1 and 2, liquid inks of Examples 2 to 10 and Comparative Examples 1 and 2 were produced in the same manner as in Example 1.

[0110] The resulting liquid inks were evaluated by the following test methods.

[0111] (Dry Lamination Strength) The viscosity of the inks 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 inks were printed on OPP film "P2161 (thickness: 20 μm)" manufactured by Toyobo Co., Ltd. using a gravure proofing machine equipped with a 35 μm deep gravure plate. A urethane-based dry lamination adhesive, Dikdry LX-470 / SI75 (manufactured by DIC), was applied to the printed surface using a dry laminating machine (manufactured by DIC Engineering). A non-oriented polypropylene film (CPP film) having an anchor coat layer (LX470, SI75) was laminated on the adhesive-coated surface, and the resulting laminate was aged at 40°C for 3 days to obtain a laminate having a configuration of "OPP film / printed layer / dry lamination adhesive layer / anchor coat layer (LX470, SI75) / CPP film." The resulting laminate was cut into a width of 15 mm and subjected to a 90-degree peel test at a pulling rate of 300 mm / min. Dry laminate strength (OPP / CPP) is expressed in N / 15 mm.

[0112] (Appearance of non-solvent (solvent-free adhesive) laminate) The viscosity of the inks 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 on 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. DIC's solvent-free adhesive 2K-SF-900A / HA-930B was applied to the printed surface using a non-solvent laminator at a coating amount of 2 g / m. ２ An aluminum vapor-deposited CPP film "Toray Film Processing 2203" was then laminated onto the adhesive-coated surface to obtain a laminated product having a configuration of "OPP film / printed layer / solvent-free adhesive layer / aluminum vapor-deposited CPP film." The appearance after lamination was evaluated and rated according to the following criteria A and B. Non-solvent laminate appearance is shown. [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.

[0113] (Cellophane tape adhesion) The viscosity of the inks 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 an OPP film "P2161 (thickness: 20 μm)" (hereinafter referred to as OPP film) 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, 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 following substrate films were also used to evaluate cellophane tape adhesion: a corona-treated polyester film "Ester E5102 (thickness: 12 μm)" (hereinafter referred to as "PET film") manufactured by Toyobo Co., Ltd.; a corona-treated nylon film "Emblem ON (thickness: 15 μm)" (hereinafter referred to as "NY film") manufactured by Unitika Ltd.; and an alumina-deposited transparent PET film "IB-PET-PUB (thickness: 12 μm)" (hereinafter referred to as "deposited PET film") 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.

[0114] (Blocking resistance) The viscosity of the inks 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 prepared using OPP film "P2161 (thickness: 20 μm)" (hereinafter referred to as OPP film) manufactured by Toyobo Co., Ltd. was stacked so that the printed and non-printed surfaces were in contact using a gravure proofing machine equipped with a gravure plate with a plate depth of 35 μm. A load of 10 kgf / cm2 was applied, and the film was left to stand in an environment of 40°C for 12 hours. After removal, the state of ink transfer to the non-printed surface was evaluated using the following five-point scale of 1 to 5. Blocking resistance was also evaluated in the same manner for the following substrate films: Toyobo Co., Ltd.'s corona-treated polyester film "Ester E5102 (thickness: 12 μm)" (hereinafter referred to as "PET film"), Unitika Ltd.'s corona-treated nylon film "Emblem ON (thickness: 15 μm)" (hereinafter referred to as "NY film"), and Dai Nippon Printing Co., Ltd.'s alumina-deposited transparent PET film "IB-PET-PUB (thickness: 12 μm)" (hereinafter referred to as "deposited PET film"). [Evaluation criteria] 5: No ink transfer observed, with 0% ink transferred to the non-printed surface. 4: Transfer observed at a rate of less than 10%. 3: Transfer observed at a rate of 10% or more but less than 20%. 2: Transfer observed at a rate of 20% or more but less than 30%. 1: Transfer observed at a rate of 30% or more.

[0115] (Highlight Transferability) In a blur test, a gravure proofing machine with a 35 μm deep gravure plate having a plate circumference of 600 mmφ, as described in the method for producing film prints, was used, and the highlight transferability was evaluated according to the following criteria A and B, as the percentage of the blurred area in the highlight printed portion (dot area less than 10%) at a printing speed of 200 m / min. (Evaluation Criteria) A: Almost no blurring, and almost no staining of non-printed portions. B: Slight blurring or slight staining of non-printed portions.

[0116] The results are shown in Tables 1 and 2. Blank spaces indicate no blending.

[0117]

[0118]

[0119] ​In the table, the abbreviations are as follows: CAP: cellulose ester FASTGEN Blue LA5380: blue pigment B15:3 SYMULER RED 4580: red pigment R146

[0120] The experimental results in Tables 1 and 2 show that the liquid ink composition of Comparative Example 1, which did not use silica as an additive, exhibited poor blocking resistance, and the liquid ink composition of Comparative Example 2, which did not use wax, exhibited poor cellophane tape adhesion. On the other hand, the liquid ink compositions of Examples 1 to 10, which used silica and wax, exhibited excellent results in both blocking resistance and adhesion to the substrate, and liquid ink resin compositions with an excellent balance of various performance properties were obtained without using a chlorine-based resin.

Claims

1. It contains a pigment, a binder resin, an organic solvent, silica, and wax, wherein the binder resin contains a polyurethane resin (A) and a polyvinyl butyral resin (B). A liquid ink composition wherein the mass ratio of silica to wax, silica:wax, is in the range of 55:45 to 95:

5.

2. The liquid ink composition according to claim 1, wherein the silica is contained in an amount of 0.1% to 5.0% by mass relative to the total amount of ink solids, and the wax is contained in an amount of 0.05% to 2.0% by mass relative to the total amount of ink solids.

3. The liquid ink composition according to claim 1, wherein the wax is a hydrocarbon wax and / or an amide wax.

4. The liquid ink composition according to claim 1, wherein water is contained in an amount of 1 to 5% by mass of the total amount of the ink composition.

5. The liquid ink composition according to claim 1, wherein the liquid ink composition does not contain a chlorine-based resin.

6. A printed article obtained by printing the liquid ink composition according to any one of claims 1 to 5.

7. A laminate having a printed layer obtained by printing the liquid ink composition according to any one of claims 1 to 5.

8. A packaging material containing the laminated material according to claim 7.