JP7537632B2 - Printed matter and laminated bodies - Google Patents

Description

The present invention relates to printed matter and laminated laminates using a liquid ink composition that can be used as a laminate gravure ink or flexographic ink for flexible packaging.

Gravure ink and flexographic ink are widely used to impart beauty and functionality to printed materials. When gravure- or flexographically printed materials are used as packaging materials, particularly food packaging, they are generally laminated. In this case, various printed materials and lamination processes are used depending on the type of contents and purpose of use.

Traditionally, printing inks using polyurethane resin and vinyl chloride-vinyl acetate copolymer resin (hereinafter referred to as "PVC") as binders have been widely used for such laminated products. These resins are a binder combination that can achieve both excellent dispersibility and high film properties, and are essential ink ingredients for achieving good printability and the various properties required of laminating inks, such as adhesion to substrates, lamination strength, and boil retort properties.

In recent years, the use of aromatic solvents such as toluene and ketone-based solvents such as methyl ethyl ketone is being restricted due to both the hygienic nature of the printing process and the harmfulness of packaging materials. For example, Patent Document 1 describes a non-toluene laminating ink composition for flexible packaging that contains, as essential components, a polypropylene glycol-containing polyurethane resin and a vinyl chloride-vinyl acetate copolymer resin having hydroxyl groups.

Furthermore, legal regulations surrounding food packaging in particular are becoming stricter worldwide, with stricter regulations on the ingredients used in packaging and their migration into food in recent years. The move away from plastic has also accelerated in recent years, increasing the demand for recyclable packaging. In the development of ink products for packaging, etc., it will be necessary in the future to design inks and packaging components using materials that are guaranteed to be safe for the human body and the environment.

In this trend, PVC is concerned as a substance that hinders the recycling of packaging because it has the following problems. The first problem is related to chemical recycling. Plastic waste discharged as general waste contains various plastics, including chlorine-based resins such as polyvinyl chloride and polyvinylidene chloride. These chlorine-based resins cause corrosion of equipment and piping when hydrogen chloride is released and hydrochloric acid is generated during the thermal decomposition process of recycling. The second problem is related to thermal recycling. In a method of reusing the energy generated when waste is incinerated, if chlorine-based resins are included during incineration, environmental hormones such as dioxins are emitted, which is a problem. Therefore, there is a need to develop an ink that has the various physical properties required for lamination inks without using chlorine-based materials such as PVC. For example, Patent Document 2 describes an ink composition that combines a specific polyurethane resin and polyvinyl butyral resin (PVB) as a printing ink that does not use chlorine-based materials.

However, with the recent diversification of packaging substrates, printing inks used for decoration or surface protection are required to have high performance and adaptability to various films. For example, when used as soft packaging materials, especially for food and sanitary products, lamination is generally added. In this case, various printed materials and lamination processes are used depending on the type of contents and the purpose of use. In addition, printed matter used for soft packaging materials generally has multiple printed layers, and is composed of a printed layer containing a white pigment as a background and a printed layer of colored pigments that form a pattern laminated on a film, and the compatibility of the film and each printed layer is also important. Therefore, it is not easy to realize an improvement in environmental compatibility by realizing a chlorine-based resin-free binder while simultaneously improving adhesion to various substrates, lamination strength, and retort suitability in addition to the basic properties of an ink, such as dispersibility, fluidity, and printability.

JP 2005-298618 A JP 2019-173037 A JP 2020-84026 A

Patent Document 2 discloses the development of an ink composition itself to improve the various physical properties required for laminating inks without using chlorine-based materials, but does not consider multiple printed layers. Therefore, there is a demand for development of a printed material that can further improve various physical properties such as lamination characteristics.

Therefore, the problem that this invention aims to solve is to provide printed matter that has excellent lamination strength and is environmentally safe without compromising the basic properties of the ink, such as dispersibility, fluidity, and stability.

After extensive investigation into applications to printed materials and laminated bodies having multiple printed layers, the inventors discovered that a specific configuration of the resins used in the printed layers and the combination of each printed layer is effective in solving the problem.

That is, the present invention relates to a printed matter having, on a film substrate, a first printed layer that does not contain polyvinyl butyral resin and a second printed layer that contains polyvinyl butyral resin.

Furthermore, the present invention relates to a laminate having the printed matter.

The present invention makes it possible to obtain a printed matter that has excellent leveling properties and lamination strength while retaining basic ink properties such as dispersibility, fluidity, and stability. Furthermore, the printed matter of the present invention has excellent ink properties such as dispersibility, fluidity, and stability even though the resin used in the printing ink does not contain a chlorine-based resin, and therefore a printed matter with excellent environmental safety can be obtained.

The present invention will be described in detail.

(Definition of words)
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 an active energy curable component, i.e., it is an active energy ray non-reactive liquid ink.

In the following explanation, all references to "ink" refer to "printing ink." Furthermore, 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.

The printed matter of the present invention is a multilayer printed matter in which a first printed layer and a second printed layer are laminated on a substrate. The first printed layer is preferably a white printed layer having a white pigment, and the second printed layer is preferably a color printed layer having at least one colorant other than the white pigment, or a colorless printed layer containing no colorant. The first printed layer is formed from a first liquid ink composition, and the second printed layer is formed from a second liquid ink composition.

<Second liquid ink composition for forming second printed layer>
First, the second liquid ink composition constituting the second printed layer will be described. The second liquid ink composition contains a binder resin, an organic solvent, and water and various additives as necessary. In addition, it is preferable that the second liquid ink composition contains a colorant other than a white pigment so that the second printed layer forms a color printed layer. The second liquid ink composition does not contain a colorant, and the second printed layer may be a colorless layer. The binder resin contained in the second liquid ink composition contains at least a polyvinyl butyral resin.

(Polyvinyl butyral resin)
The polyvinyl butyral resin contained in the second liquid ink composition is not particularly limited and may be any known resin. In general, a reaction product obtained by acetalizing polyvinyl alcohol with butyraldehyde through a known reaction may be used.

The weight average molecular weight of the polyvinyl butyral resin 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 within the above range, it is possible to obtain an ink with an excellent balance of fluidity and dispersibility.

The glass transition temperature (hereinafter sometimes referred to as Tg) of the polyvinyl butyral resin 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°C to 110°C. In the present invention, the glass transition temperature is obtained by measurement using a differential scanning calorimeter.

The amount of hydroxyl groups in the polyvinyl butyral resin is preferably in the range of 10 to 30% by mass, and more preferably 15 to 25% by mass. By setting the amount of hydroxyl groups in the polyvinyl butyral resin within the above range, an ink with an excellent balance of fluidity and dispersibility can be obtained.

In addition, the amount of acetyl groups in the polyvinyl butyral resin is preferably 10% by mass or less, and more preferably 8% by mass. By setting the amount of acetyl groups in the polyvinyl butyral resin within the above range, an ink with an excellent balance between fluidity and dispersibility can be obtained.

The polyvinyl butyral resin content (solid content of polyvinyl butyral resin) 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, based on 100% by mass of the ink. Adding a total of 0.1% or more of polyvinyl butyral resin tends to maintain the adhesion and transferability of the ink film, while keeping the total at 5% by mass or less can maintain the lamination strength and boil/retort resistance of the ink. The lower limit of the solid weight ratio in the ink is preferably 0.1% by mass, more preferably 0.2% by mass, and most preferably 0.3% by mass. The upper limit of the solid weight ratio in the ink is preferably 45% by mass, more preferably 40% by mass, more preferably 30% by mass, more preferably 20% by mass, more preferably 15% by mass, and most preferably 10% by mass.

The second liquid ink composition can improve dispersibility by containing a polyvinyl butyral resin. Since the constituent elements of polyvinyl butyral resin are only carbon atoms, hydrogen atoms, and oxygen atoms, the risk of environmental pollution can be reduced during the life cycle of products such as packages that use the vinyl butyral resin.

In order to obtain the effects of the present invention, the total mass of the polyvinyl butyral resin relative to the total mass of the resins contained in the second liquid ink composition (second printing layer) is preferably 5 to 100 mass% or more, more preferably 10 to 75 mass% or more, and even more preferably 15 to 50 mass% or more.
(Other binder resins)
The second liquid ink composition of the present invention uses a polyvinyl butyral resin as a binder resin, and may contain a binder resin that can be used in combination in the technical field of liquid ink. From the viewpoint of reducing the environmental load, the binder resin that can be used in combination is preferably a resin that does not contain a chlorine-based component, and examples of the binder resin that can be used in combination include polyurethane resin, ethylene-vinyl acetate copolymer resin, vinyl acetate resin, polyamide resin, acrylic resin, polyester resin, alkyd resin, rosin-based resin, rosin-modified maleic acid resin, ketone resin, cyclized rubber, petroleum resin, and cellulose-based resin. Of these, it is preferable to contain a polyurethane resin, a rosin-modified maleic acid resin, a cellulose-based resin, a polyester resin, or an acrylic resin.

(Polyurethane resin)
By using a urethane resin in combination as the other binder resin, the adhesion, lamination strength, and retort resistance can be further improved.

The polyurethane resin is not particularly limited as long as it is a polyurethane resin obtained by reacting a polyol with a polyisocyanate. As the polyol, it is preferable to use a polyester polyol and/or a polyether 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 the laminate strength by increasing the cohesive energy by introducing an ester group.

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. Specifically, for example, 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.

As the polycarboxylic acid or anhydride thereof, various known polycarboxylic acids commonly used in the production of polyester polyols can be used, and one or more of them may be used in combination. Specifically, for example, 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 anhydrides of these acids, aromatic dicarboxylic acids such as phthalic acid, isophthalic acid, terephthalic acid, and 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 anhydrides thereof, benzenetetracarboxylic acid, benzenepentacarboxylic acid, benzenehexacarboxylic acid, and anhydrides of these acids, etc. can be used.

In addition, the polyester polyol may be any of various known polyester polyols commonly 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 types may be used in combination.

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:

Measurement device: High-speed GPC device ("HLC-8220GPC" manufactured by Tosoh Corporation)
Column: The following columns manufactured by Tosoh Corporation were used, connected in series.

"TSKgel G5000" (7.8mm I.D. x 30cm) x 1 "TSKgel G4000" (7.8mm I.D. x 30cm) x 1 "TSKgel G3000" (7.8mm I.D. x 30cm) x 1 "TSKgel G2000" (7.8mm I.D. x 30cm) x 1 Detector: RI (differential refractometer)
Column temperature: 40°C
Eluent: tetrahydrofuran (THF)
Flow rate: 1.0 mL/min Injection volume: 100 μL (sample concentration 0.4% by mass in tetrahydrofuran solution)
Standard sample: A calibration curve was prepared using the following standard polystyrene.

[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
As the polyether polyol, various known polyether polyols generally used in the production of polyurethane resins can be used, and one or more of them may be used in combination. For example, polyether polyols of polymers or copolymers of methylene oxide, ethylene oxide, propylene oxide, tetrahydrofuran, etc. can be mentioned. Specifically, known general-purpose ones such as polyethylene glycol, polypropylene glycol, and polytetramethylene glycol can be used. By containing polyether polyol, adhesion, especially on a high-performance barrier film, is greatly improved, resulting in excellent blocking resistance and laminate strength.

It is preferable that the polyether polyol has a number average molecular weight of 100 to 3500. If the number average molecular weight of the polyether polyol is less than 100, the polyurethane resin film tends to become hard and the adhesion to the polyester film decreases. If the number average molecular weight is more than 3500, the polyurethane resin film tends to become brittle and the blocking resistance of the ink film decreases.

It is preferable to use a polyurethane resin in which polyester polyol and polyether polyol are used as reaction raw materials, and the mass ratio of polyester polyol is high in the total mass of the polyester polyol and polyether polyol. In other words, by adjusting the mass ratio of polyester polyol in the polyol structure of the polyurethane resin so that polyester polyol is more, it is possible to further improve boil resistance, retort resistance, and laminate strength. In addition, the inclusion of polyether polyol can improve the dispersibility and fluidity of the ink, and also has the effect of improving adhesion.

Specifically, the mass ratio of polyester polyol to polyether polyol in the polyol structure is preferably in the range of 55:45 to 99:1, more preferably in the range of 60:40 to 98:2, and even more preferably in the range of 70:30 to 97:3.

In addition, as a polyol to be used in combination with polyurethane resin as necessary, 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. For example, saturated polyols such as ethylene glycol, 1,2-propanediol, 1,3-propanediol, 2-methyl-1,3-propanediol, 2-ethyl-2-butyl-1,3-propanediol, 1,3-butanediol, 1,4-butanediol, neopentyl glycol, pentanediol, 3-methyl-1,5-pentanediol, 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 can be used. 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 the corresponding methacrylic acid derivatives, etc., with, for example, acrylic acid, methacrylic acid, or an ester thereof.

Diisocyanate compounds used in polyurethane resins include 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 the diisocyanate include 1,4-diisocyanate, xylylene diisocyanate, isophorone diisocyanate, dimeryl diisocyanate, dicyclohexylmethane-4,4'-diisocyanate, 1,3-bis(isocyanatemethyl)cyclohexane, methylcyclohexane diisocyanate, norbornane diisocyanate, m-tetramethylxylylene diisocyanate, 4,4-diphenylmethane diisocyanate, tolylene diisocyanate, bis-chloromethyl-diphenylmethane-diisocyanate, 2,6-diisocyanate-benzyl chloride, and dimer diisocyanate in which the carboxyl group of a dimer acid is converted to an isocyanate group. These diisocyanate compounds can be used alone or in combination of two or more kinds.

Chain extenders used in polyurethane resins include ethylenediamine, propylenediamine, hexamethylenediamine, diethylenetriamine, triethylenetetramine, isophoronediamine, dicyclohexylmethane-4,4'-diamine, etc., as well as amines having hydroxyl groups in the molecule, such as 2-hydroxyethylethylenediamine, 2-hydroxyethylpropyldiamine, 2-hydroxyethylpropylenediamine, di-2-hydroxyethylethylenediamine, di-2-hydroxyethylpropylenediamine, 2-hydroxypropylethylenediamine, di-2-hydroxypropylethylenediamine, and di-2-hydroxypropylethylenediamine. These chain extenders can be used alone or in combination of two or more.

A monovalent active hydrogen compound can also be used as an end-blocking agent for the purpose of stopping 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, amino acids such as glycine and L-alanine can be used as reaction stoppers. These end-blocking agents can be used alone or in combination of two or more.

Polyurethane resins are produced, for example, by reacting polypropylene glycol and a polyol used in combination with a diisocyanate compound in a ratio that results in an excess of isocyanate groups to obtain a prepolymer with terminal isocyanate groups, and then reacting the resulting prepolymer with a chain extender and/or a terminal blocking agent in a suitable solvent, i.e., ester solvents such as ethyl acetate, propyl acetate, and butyl acetate that are commonly used as solvents for non-toluene gravure inks; ketone solvents such as acetone, methyl ethyl ketone, and methyl isobutyl ketone; alcohol solvents such as methanol, ethanol, isopropyl alcohol, and n-butanol; hydrocarbon solvents such as methylcyclohexane and ethylcyclohexane; or a mixture of these solvents, in a two-stage method, or by reacting polypropylene glycol and a polyol used in combination with the diisocyanate compound, the chain extender, and/or the terminal blocking agent at once in a suitable solvent among the above. Of these methods, the two-stage method is preferable for obtaining a uniform polyurethane resin. In addition, when producing a polyurethane resin by a two-stage method, it is preferable to react the chain extender and/or the end-capping agent so that the total amino group (equivalent ratio) is 1/0.9 to 1.3. When the equivalent ratio of the isocyanate group to the amino group is less than 1/1.3, the chain extender and/or the end-capping agent remain unreacted, and the polyurethane resin may turn yellow or emit 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.

The weight-average molecular weight of the polyurethane resin obtained in this manner 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 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 composition tends to be high and the gloss of the printed film tends to be reduced.

When a polyurethane resin is used as a co-resin, the content of the polyurethane resin used in the liquid ink composition in the ink (solid content of the polyurethane resin) is preferably 1% by mass or more, 3% by mass or more, or 5% by mass or more relative to the total mass of the ink, from the viewpoint of ensuring sufficient adhesion of the ink to the printed material. On the other hand, from the viewpoint of appropriate ink viscosity and work efficiency during ink production and printing, it is preferably 25% by mass or less, more preferably 20% by mass or less, and more preferably 15% by mass or less.

In addition, the lower limit of the solids weight ratio of the polyurethane resin in the ink is preferably 1% by mass, more preferably 5% by mass, more preferably 10% by mass, more preferably 15% by mass, and even more preferably 20% by mass. In addition, the upper limit of the solids weight ratio in the ink is preferably 95% by mass, more preferably 90% by mass, more preferably 80% by mass, more preferably 75% by mass, and even more preferably 70% by mass.

(Cellulose-based resin)
Examples of cellulose resins include cellulose acetate propionate, cellulose acetate butyrate and other cellulose ester resins, nitrocellulose (also called soluble cellulose), hydroxyalkyl cellulose, and carboxyalkyl cellulose. The cellulose ester resin preferably has an alkyl group, and examples of the alkyl group include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a pentyl group, and a hexyl group, and the alkyl group may further have a substituent.

Of the above, cellulose acetate propionate, cellulose acetate butyrate, and nitrocellulose are preferred as cellulose-based resins. The molecular weight is preferably a weight average molecular weight of 5,000 to 200,000, and more preferably 10,000 to 50,000. In addition, the glass transition temperature is preferably 120°C to 180°C. When used in combination with the polyurethane resin (A) of the present invention, it is expected that blocking resistance, scratch resistance, and other physical properties of the ink film will be improved.

Nitrocellulose (soluble cellulose) is preferably obtained by reacting natural cellulose with nitric acid to produce a nitric acid ester in which the three hydroxyl groups in the six-membered ring of the anhydrous glucopyranose group in the natural cellulose are replaced with nitric acid groups.

In particular, the second liquid ink composition preferably contains at least a polyvinyl butyral resin and a polyurethane resin as binder resins. In order to obtain the effects of the present invention, the total mass of the polyvinyl butyral resin and the polyurethane resin relative to the total mass of the binder resins is preferably 80% by mass or more, more preferably 85% by mass or more, even more preferably 90% by mass or more, and even more preferably 95% by mass or more.

(Coloring Agent)
The colorant used in the second liquid ink composition preferably contains at least a colorant other than a white pigment.

Examples of colorants include organic and inorganic pigments and dyes that are used in general inks, paints, and recording agents, etc. Examples of organic pigments include soluble azo-based, insoluble azo-based, azo-based, phthalocyanine-based, halogenated phthalocyanine-based, anthraquinone-based, anthanthrone-based, dianthraquinonyl-based, anthrapyrimidine-based, perylene-based, perinone-based, quinacridone-based, thioindigo-based, dioxazine-based, isoindolinone-based, quinophthalone-based, azomethine azo-based, flavanthrone-based, diketopyrrolopyrrole-based, isoindoline-based, indanthrone-based, and carbon black-based pigments.
In addition, examples of the pigments include carmine 6B, lake red C, permanent red 2B, disazo yellow, pyrazolone orange, carmine FB, chromophthalic yellow, chromophthalic 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. In addition, both non-acid-treated pigments and acid-treated pigments can be used. Specific examples of preferred organic pigments are given below.

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.

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. Examples of the pigment blue include C.I. Pigment Blue 63, C.I. Pigment Blue 64, C.I. Pigment Blue 75, C.I. Pigment Blue 79, and C.I. Pigment Blue 80.

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.

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. 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. 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. 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. Pigment Red 271, C.I. Pigment Red 272, C.I. Pigment Red 279, and the like.

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.

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 the pigments include C.I. Pigment Yellow 174, C.I. Pigment Yellow 180, C.I. Pigment Yellow 185 and C.I. Pigment Yellow 213.

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 Range 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.

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

Among them, preferred pigments are 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 an indigo pigment, 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 the pigments 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 selected from these groups.

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, and zircon. Aluminum is in powder or paste form, but it is preferable to use it in paste form from the standpoint of ease of handling and safety, and whether leafing or non-leafing is used is selected appropriately from the standpoint of brightness and concentration.

The colorant is preferably contained in an amount sufficient to ensure the concentration and coloring power of the second liquid ink composition, i.e., 1 to 60% by mass relative to the total mass of the ink, or 10 to 90% by mass in terms of the weight ratio of solids in the ink. The colorant may be used alone or in combination of two or more kinds. The second liquid ink composition may be a colorless liquid ink composition that does not contain a colorant.

The second liquid ink composition may further contain, as necessary, a co-used resin, an extender pigment, a pigment dispersant, a leveling agent, an antifoaming agent, a wax, a plasticizer, an infrared absorber, an ultraviolet absorber, a fragrance, a flame retardant, etc.

(Organic Solvent)
As the organic solvent used in the second liquid ink composition, various organic solvents can be used, for example, aromatic organic solvents such as toluene and xylene, ketone-based solvents such as acetone, methyl ethyl ketone and methyl isobutyl ketone, ester-based solvents such as ethyl acetate, n-propyl acetate, butyl acetate and propylene glycol monomethyl ether acetate, and alcohol-based solvents such as n-propanol, isopropanol, n-butanol and propylene glycol monomethyl ether, which can be used alone or in a mixture of two or more. 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-based solvents.

The second liquid ink composition may contain water as a volatile component together with the organic solvent. The water content is preferably less than 10% by mass of the total ink composition. The addition of water makes it possible to control the drying properties of the ink, and in particular in gravure printing, the characteristic gradation areas with little ink transfer can be beautifully reproduced. Furthermore, a content of water in the range of 1 to 5% by mass of the total ink composition is particularly preferred as this provides good printability.

The addition of water in this way 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 second liquid ink composition 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 fluidity.

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 dispersing machine, the packing rate of the grinding media, the dispersion processing time, the discharge speed of the pigment dispersion, the viscosity of the pigment dispersion, etc. As the dispersing machine, a commonly used machine such as a roller mill, ball mill, pebble mill, attritor, sand mill, etc. can be used.

If the ink contains air bubbles or unexpectedly large particles, it is preferable to remove them by filtration or other methods, as they will reduce the quality of the printed matter. Conventional filters can be used.

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 dispersing it appropriately, 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 type and amount of raw materials used, such as polyurethane resin, colorant, 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.

The hues of the liquid ink composition used in the second printing layer are five process basic colors, yellow, red, indigo, black, and white, and three process gamut colors, red (orange), grass (green), and purple, depending on the type of pigment used. In addition, transparent yellow, peony, vermilion, brown, gold, silver, pearl, and a nearly transparent medium (containing an extender pigment as necessary) for adjusting color density are prepared as base colors. Ink for boiling retort is appropriately selected in consideration of the migration property and heat resistance of the pigment. The base ink of each hue 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 alone or mixed.

<First liquid ink composition for forming first printed layer>
The first liquid ink composition forms a first printed layer (white printed layer) and contains a binder resin, a white pigment, an organic solvent, and, if necessary, water and various additives, etc. The binder resin contained in the first liquid ink composition does not contain a polyvinyl butyral resin.

(Binder resin)
The binder resin is a binder resin used in liquid inks that are usually applied to printing methods using printing plates, such as gravure inks or flexographic inks, and is not particularly limited as long as it is a resin other than polyvinyl butyral resin. Examples of the resin include polyurethane resins, vinyl chloride-vinyl acetate copolymer resins, chlorinated polypropylene resins, ethylene-vinyl acetate copolymer resins, vinyl acetate resins, polyamide resins, acrylic resins, polyester resins, alkyd resins, polyvinyl chloride resins, rosin-based resins, rosin-modified maleic acid resins, ketone resins, cyclized rubbers, chlorinated rubbers, polyvinyl butyral resins, and petroleum resins. These resins can be used alone or in combination of two or more. Among them, polyurethane resins are preferably used as the main binder resin because of their excellent adhesion to film substrates, blocking resistance, lamination suitability, and highlight transferability. When a urethane resin is used as the main binder, the ratio of the urethane resin to the total amount of resins in the ink is preferably 50% by mass or more, and more preferably 60% by mass or more.

(Polyurethane resin)
The polyurethane resin used in the first printing layer is not particularly limited as long as it is a polyurethane resin obtained by reacting a polyol with a polyisocyanate. As the polyol, it is preferable to use a polyester polyol and/or a polyether polyol, and these are the same as the polyester polyol and/or the polyether polyol used in the first printing layer (first liquid ink composition) described above.

In the polyurethane resin used in the first printing layer, the type of polyol is not particularly limited, but from the viewpoints of boil resistance, retort resistance, and laminate strength, it is preferable that the proportion of polyester polyol is high, and it is more preferable to use a polyol consisting of polyester polyol alone. Specifically, the mass ratio of polyester polyol and polyether polyol in the polyol structure is preferably in the range of 55:45 to 100:0, more preferably in the range of 60:40 to 100:0, and even more preferably in the range of 70:30 to 100:0.

As the diisocyanate compound used in the polyurethane resin, various known diisocyanate compounds commonly used in the production of polyurethane resins, such as those used in the first printing layer (first liquid ink composition) described above, can be used.

The weight average molecular weight of the polyurethane resin is preferably in the range of 15,000 to 100,000, similar to the polyurethane resin used in the second printed layer, and more preferably in the range of 15,000 to 80,000. If the weight average molecular weight of the polyurethane resin 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, whereas if it exceeds 100,000, the viscosity of the resulting ink composition tends to be high and the gloss of the printed film tends to be reduced.

The first printing layer preferably uses a polyurethane resin as the main binder in combination with a cellulose-based resin and/or a maleic acid resin. The cellulose-based resin may be the same as the cellulose-based resin used in the second printing layer described above.

Examples of white pigments include titanium oxide, zinc sulfide, white lead, zinc oxide, lithopone, antimony white, basic lead sulfate, basic lead silicate, barium sulfate, calcium carbonate, gypsum, silica, etc. Among these, titanium oxide is preferred from the standpoints of coloring power, hiding power, chemical resistance, and weather resistance, and from the standpoint of printing performance, the titanium oxide may be treated with silica and/or alumina.

The amount of white pigment content will vary depending on the desired ink performance, but for white inks that require standard hiding power and high plate fogging, it is usually designed to contain approximately 20 to 40% by mass of the total ink, whereas for white inks that require extremely high hiding power, it may be designed to contain approximately 40 to 60% by mass.

In the first liquid ink composition, the components other than the white pigment, such as organic solvents and other additives, may be the same as those in the liquid ink composition (I) described above. It is preferable that both the second liquid ink composition and the first liquid ink composition do not contain a chlorine-based resin such as a vinyl chloride vinyl acetate copolymer. According to the present invention, excellent dispersibility and laminate strength can be obtained due to a composition with low environmental impact.

(Printed matter)
The printed matter of the present invention is a multilayer printed matter in which a first printed layer and a second printed layer are laminated on a film substrate. The first printed layer and the second printed layer can be formed by printing various film substrates using the above-mentioned liquid ink composition, respectively, and are useful as inks for gravure printing using a gravure printing plate such as an electronic engraving intaglio or an etching type intaglio plate, or for flexographic printing using a flexographic printing plate such as a resin plate, but excluding inks for inkjet printing in which ink is ejected from an inkjet nozzle without using a plate.

In other words, in the case of inkjet ink, the ink droplets ejected from the nozzle directly adhere to the substrate to form a printed item, whereas in the case of the liquid printing ink of the present invention, the printing ink is first adhered to and transferred to a printing plate or printing pattern, and then the ink alone is again adhered to the substrate and dried as necessary to form a printed item.

Examples of the film substrate include films and laminates made of thermoplastic resins such as polyethylene terephthalate (hereinafter sometimes referred to as PET), polyethylene naphthalate, polytrimethylene terephthalate, polytrimethylene naphthalate, polybutylene terephthalate, and polybutylene naphthalate; polyamides such as nylon 6, nylon 66, and nylon 46; polyhydroxycarboxylic acids such as polylactic acid; aliphatic polyester resins such as poly(ethylene succinate) and poly(butylene succinate); polyolefins such as polypropylene (CPP: unstretched polypropylene film, OPP: biaxially oriented polypropylene film), polyethylene (LLDPE: low density polyethylene film, HDPE: high density polyethylene film); polyimide, polyarylate, polystyrene, polyacrylonitrile, polyvinyl alcohol, ethylene-vinyl alcohol copolymers, and mixtures thereof. Among these, films made of polyester, polyamide, polyethylene, and polypropylene are preferably used.

It is also preferable to use a film made of a material containing biomass-derived components as the film substrate. Biomass films are sold by various companies, and for example, sheets such as those listed in the list of biomass certified products listed by the Japan Organics Resources Association can be used.

A specific well-known film is made from biomass-derived ethylene glycol. Biomass-derived ethylene glycol is made from ethanol (biomass ethanol) produced from biomass. For example, biomass-derived ethylene glycol can be obtained by a method of producing ethylene glycol from biomass ethanol via ethylene oxide using a conventionally known method. Commercially available biomass ethylene glycol may also be used, and for example, biomass ethylene glycol available from India Glycoal Limited can be suitably used.

Alternatively, products using biomass raw materials classified by the biomass plastic degree specified by ISO16620 or ASTM D6866 are also on the market. Radioactive carbon 14C exists in the atmosphere at a ratio of 1 in 1012 particles, and this ratio does not change with atmospheric carbon dioxide, so this ratio does not change even in plants that fix this carbon dioxide through photosynthesis. For this reason, the carbon in plant-derived resin contains radioactive carbon 14C. In contrast, the carbon in fossil fuel-derived resin contains almost no radioactive carbon 14C. Therefore, by measuring the concentration of radioactive carbon 14C in the resin with an accelerator mass spectrometer, the proportion of plant-derived resin in the resin, i.e., the biomass plastic degree, can be determined. Examples of plant-derived low-density polyethylene, which is a biomass plastic having a biomass plastic content of 80% or more, preferably 90% or more as specified by ISO 16620 or ASTM D6866, include products manufactured by Braskem under the trade names "SBC818", "SPB608", "SBF0323HC", "STN7006", "SEB853", and "SPB681", and films using these as raw materials can be suitably used.

For example, as an alternative to conventional polyethylene terephthalate films using petroleum-based raw materials, films containing biomass polyesters and biomass polyethylene terephthalate, which have biomass-derived ethylene glycol as the diol unit and fossil fuel-derived dicarboxylic acids as the dicarboxylic acid units, are known.
The dicarboxylic acid unit of the biomass polyester uses a dicarboxylic acid derived from a fossil fuel. As the dicarboxylic acid, an aromatic dicarboxylic acid, an aliphatic dicarboxylic acid, and a derivative thereof can be used without limitation.

In addition to the above diol component and dicarboxylic acid component, the copolymer may be a copolymer polyester containing a copolymer component as a third component, such as a bifunctional oxycarboxylic acid or at least one polyfunctional compound selected from the group consisting of a trifunctional or higher functional polyhydric alcohol, a trifunctional or higher functional polycarboxylic acid and/or its anhydride, and a trifunctional or higher functional oxycarboxylic acid, in order to form a crosslinked structure.

In addition, for example, as an alternative to conventional polyolefin-based films that use petroleum-based raw materials, biomass polyolefin-based films such as biomass polyethylene-based films containing polyethylene resins made from biomass-derived ethylene glycol and biomass polyethylene-polypropylene-based films are also known.

The polyethylene resin is not particularly limited except that ethylene glycol derived from the biomass is used as part of the raw material, and examples thereof include ethylene homopolymers, copolymers of ethylene and α-olefins with ethylene as the main component (ethylene-α-olefin copolymers containing 90% or more by mass of ethylene units), and the like, which can be used alone or in combination of two or more.

The α-olefin constituting the copolymer of ethylene and α-olefin is not particularly limited, and examples thereof include α-olefins having 4 to 8 carbon atoms, such as 1-butene, 4-methyl-1-pentene, 1-hexene, and 1-octene. Known polyethylene resins, such as low-density polyethylene resin, medium-density polyethylene resin, and linear low-density polyethylene resin, can be used.

Among these, from the viewpoint of making it even more difficult for damage such as holes or tears to occur even when the films rub against each other, linear low-density polyethylene resin (LLDPE) (a copolymer of ethylene and 1-hexene, or a copolymer of ethylene and 1-octene) is preferred, and linear low-density polyethylene resin having a density of 0.910 to 0.925 g/cm3 is more preferred.

Films and sheets containing starch, a biomass raw material, and polylactic acid are also known. These can be selected and used as appropriate depending on the application.

The biomass film may be a laminate of multiple biomass films, or a laminate of a conventional petroleum-based film and a biomass film.

These petroleum-based films and biomass films may be laminated with a vapor-deposited layer of a metal such as aluminum or a metal oxide such as silica or alumina, may use a metal foil, may be used in combination with a barrier film containing a gas barrier layer such as polyvinyl alcohol, an ethylene-vinyl alcohol copolymer, or vinylidene chloride, or may be coated with polyvinyl alcohol. By using such a film, a laminate with high barrier properties against water vapor, oxygen, alcohol, inert gases, volatile organic compounds (fragrances), etc. can be obtained.

These films may be unstretched or may have been stretched, and there is no limitation on the manufacturing method. Stretching methods generally involve melt-extruding a resin into a sheet using an extrusion film-making method or the like, followed by simultaneous biaxial stretching or sequential biaxial stretching. In the case of sequential biaxial stretching, it is common to first perform longitudinal stretching, and then transverse stretching. Specifically, a method that combines longitudinal stretching using the speed difference between rolls and transverse stretching using a tenter is often used.

The thickness of the base film is not particularly limited, but is usually in the range of 1 to 500 μm. The film surface may be subjected to various surface treatments such as flame treatment and corona discharge treatment as necessary to form an adhesive layer without defects such as film breaks or repellency.

The printing method can be known printing methods such as gravure printing and flexographic printing, but gravure printing is particularly preferred.

In the above printing method, i.e., after the printing ink is once adhered and transferred to a printing plate or a printing pattern, only the ink is adhered again to a substrate and, if necessary, dried or cured in an oven to fix it, thereby obtaining a printed matter. The film thickness of the printing ink formed by the gravure printing method or the flexographic printing method using the liquid printing ink of the present invention is, for example, 10 μm or less, preferably 5 μm or less.

In the printed matter of the present invention, the above-mentioned liquid ink composition can be preferably used as a surface printing ink, reverse printing ink, or laminating ink on a film substrate. When used as a surface printing ink, a separate overprint varnish layer can also be provided. On the other hand, when used as a reverse printing ink, a separate anchor coat varnish layer can also be provided.

In the printed matter, the order in which the first and second printed layers are provided is not particularly limited. For example, the first printed layer may be a color printed layer and the second printed layer may be a white printed layer, and they may be laminated in the order of film substrate/color printed layer/white printed layer, or film substrate/white printed layer/color printed layer. For example, the second printed layer (color printed layer) can be used to form a pattern using a colorant, and the first printed layer formed with a liquid printing ink containing a white pigment can be used as the background of the pattern.

It may further include a third printed layer as another printed layer, which may include, for example, a white pigment, and if it is an overprint varnish, it may not include a colorant (white pigment and colored pigment).

(Laminate)
The laminate of the present invention is obtained by laminating a plurality of substrates, and has a printed layer of the liquid printing ink of the present invention on at least one of the substrates. The substrates can be laminated by lamination with an adhesive or by extrusion lamination.

More specifically, the laminate has the following structure:
(1) Base film 1/printed layer/adhesive layer 1/sealant film (2) Base film 1/printed layer/adhesive layer 1/metal-vapor-deposited unstretched film (3) Base film 1/printed layer/adhesive layer 1/metal-vapor-deposited stretched film (4) Transparent vapor-deposited stretched film/printed layer/adhesive layer 1/sealant film (5) Base film 1/printed layer/adhesive layer 1/base film 2/adhesive layer 2/sealant film (6) Base film 1/printed layer/adhesive layer 1/metal-vapor-deposited stretched film/adhesive layer 2/sealant film Film (7) Base film 1/printed layer/adhesive layer 1/transparent vapor deposition stretched film/adhesive layer 2/sealant film (8) Base film 1/printed layer/adhesive layer 1/metal layer/adhesive layer 2/sealant film (9) Base film 1/printed layer/adhesive layer 1/base film 2/adhesive layer 2/metal layer/adhesive layer 3/sealant film (10) Base film 1/printed layer/adhesive layer 1/metal layer/adhesive layer 2/base film 2/adhesive layer 3/sealant film, etc., but are not limited thereto. The above-mentioned "base film 1/and printed layer" corresponds to the above-mentioned printed matter having a white printed layer and a color printed layer on a film base. In addition, in the above-mentioned configurations (1) to (10), a printed layer may be provided on the surface of the base film 1 on the side of the adhesive layer 1, but a printed layer may be provided on the surface (front surface) of the base film 1 opposite to the adhesive layer 1, or a printed layer may be provided on the base film 2.

Examples of the base film 1 used in configuration (1) include OPP film, PET film, nylon film (hereinafter also referred to as Ny film), etc. The base film 1 may also be coated with a coating intended to improve gas barrier properties or ink receptivity when providing a printing layer, which will be described later. Examples of commercially available coated base films 1 include K-OPP film and K-PET film. Examples of sealant films include CPP film and LLDPE film.

Examples of the base film 1 used in structures (2) and (3) include an OPP film, a PET film, etc. As a metal-vapor-deposited unstretched film, a VM-CPP film obtained by depositing a metal such as aluminum on a CPP film can be used, and as a metal-vapor-deposited stretched film, a VM-OPP film obtained by depositing a metal such as aluminum on an OPP film can be used.

Examples of the transparent vapor-deposited stretched film used in configuration (4) include films in which silica or alumina has been vapor-deposited onto OPP film, PET film, nylon film, etc. For the purpose of protecting the inorganic vapor-deposited layer of silica or alumina, a film in which a coating has been applied onto the vapor-deposited layer may also be used. Examples of the sealant film include the same as those in configuration (1).

The base film 1 used in the structure (5) may be a PET film or the like. The base film 2 may be a nylon film or the like. The sealant film may be the same as that used in the structure (1).

The base film 1 in structure (6) may be the same as those in structures (2) and (3). Metal-vapor-deposited stretched films may be VM-OPP films or VM-PET films in which a metal such as aluminum is vapor-deposited on an OPP film or a PET film. The sealant film may be the same as those in structure (1).

The base film 1 of the structure (7) may be a PET film or the like. The transparent vapor deposition stretched film may be the same as that of the structure (4). The sealant film may be the same as that of the structure (1).

The base film 1 of the structure (8) may be a PET film or the like. The metal layer may be an aluminum foil or the like. The sealant film may be the same as that of the structure (1).

In the structures (9) and (10), the base film 1 may be a PET film or the like. The base film 2 may be a nylon film or the like. The metal layer may be an aluminum foil or the like. The sealant film may be the same as that in the structure (1).
(Adhesive Layer)
The adhesive layer may be formed from a known adhesive for film lamination. When laminating by extrusion lamination, a known anchor coating agent for extrusion lamination may be used as an adhesive auxiliary. When a material having gas barrier properties is used as the adhesive or anchor coating agent, a laminate having particularly excellent barrier properties can be obtained.

Particularly preferred adhesives with excellent gas barrier properties are those which satisfy at least one of the following conditions: the oxygen barrier property of the cured coating film of the adhesive applied at 3 g/ ^m2 (solid content) is 300 cc/ ^m2 /day/atm or less, or the water vapor barrier property is 120 g/ ^m2 /day or less. Commercially available products include the "PASLIM" series, such as PASLIM VM001 and PASLIM J350X manufactured by DIC Corporation, and "Maxive" manufactured by Mitsubishi Gas Chemical Company, Inc.

The adhesive layer can be made of any known material without any particular limitations, but preferably contains a cured product of a polyol and an isocyanate compound. When these polyols and/or isocyanate compounds containing biomass-derived components are used, a laminate with a high biomass content can be obtained, thereby reducing the environmental impact.

In addition, the adhesive may contain an adhesion promoter, an acid anhydride, a compound having an oxygen scavenging function, a tackifier, a stabilizer for the gas barrier adhesive (antioxidant, heat stabilizer, UV absorber, etc.), a plasticizer, an antistatic agent, a lubricant, an antiblocking agent, a colorant, a crystal nucleating agent, etc. These various additives may be added in advance to either or both of the polyol composition (A) and the polyisocyanate composition (B), or may be added when the polyol composition (A) and the polyisocyanate composition (B) are mixed.

The gas barrier adhesive used may be either a solvent-based or solventless type. When the gas barrier adhesive used is a solvent-based type, the adhesive of the present invention is applied onto the surface of the printed layer printed on the first substrate using a roll such as a gravure roll, and the organic solvent is evaporated by heating in an oven or the like, and then the other substrate is laminated to obtain the laminate of the present invention. After lamination, it is preferable to carry out an aging treatment. The aging temperature is preferably room temperature to 80°C, and the aging time is preferably 12 to 240 hours.

When the gas barrier adhesive used is a solventless type, the adhesive of the present invention, which has been preheated to about 40°C to 100°C, is applied to the printed layer surface printed on the first substrate using a roll such as a gravure roll, and the other substrate is immediately laminated to obtain the laminate of the present invention. After lamination, it is preferable to carry out an aging treatment. The aging temperature is preferably room temperature to 70°C, and the aging time is preferably 6 to 240 hours.

When the gas barrier adhesive used is used as an adhesive auxiliary, the adhesive auxiliary of the present invention is applied to the surface of the printed layer printed on the first substrate using a roll such as a gravure roll, the organic solvent is evaporated by heating in an oven or the like, and then the polymer material melted by an extruder is laminated to obtain the laminate of the present invention. As the polymer material to be melted, polyolefin resins such as low-density polyethylene resin, linear low-density polyethylene resin, and ethylene-vinyl acetate copolymer resin are preferred. The aging temperature is preferably room temperature to 70°C, and the aging time is preferably 6 to 240 hours.

The coating amount of the gas barrier adhesive used is adjusted appropriately. In the case of a solvent-based adhesive, the solid content is adjusted to, for example, 1 g/ ^m2 to 10 g/ ^m2 , preferably 2 g/ ^m2 to 5 g/ ^m2 . In the case of a solventless adhesive, the coating amount of the adhesive is, for example, 1 g/ ^m2 to 5 g/ ^m2 , preferably 1 g/ ^m2 to 3 g/ ^m2 .

When the adhesive is used as an adhesion promoter, the amount of application is appropriately adjusted, and is, for example, 0.03 g/m ² or more and 2 g/m ² or less (solid content).

(Laminate other layers)
The laminate of the present invention may be used alone or may further include other films or substrates. As the other substrates, in addition to the above-mentioned stretched film, unstretched film, and transparent vapor deposition film, porous substrates such as paper, wood, and leather can also be used. The adhesive used when bonding the other substrates may or may not be a gas barrier adhesive as described above.

<Packaging materials>
The printed matter and laminate of the present invention can be used as a multi-layer packaging material for the purpose of protecting food, medicines, etc. When used as a multi-layer packaging material, the layer structure can be changed depending on the contents, the environment of use, and the form of use.

The packaging material of the present invention can be obtained, for example, by using the laminate of the present invention, overlapping the surfaces of the sealant film of the laminate so that they face each other, and then heat-sealing the peripheral edge. Examples of the bag-making method include folding or overlapping the laminate of the present invention so that the surfaces of the inner layers (the surfaces of the sealant film) face each other, and heat-sealing the peripheral edge, for example, by a side seal type, a two-sided seal type, a three-sided seal type, a four-sided seal type, an envelope seal type, a grooving seal type, a pleated seal type, a flat bottom seal type, a square bottom seal type, a gusset type, or other heat seal type. The packaging material of the present invention can take various forms depending on the contents, the environment in which it is used, and the form of use. Self-supporting packaging materials (standing pouches) are also possible. Heat sealing can be performed by known methods such as bar seal, rotary roll seal, belt seal, impulse seal, high frequency seal, and ultrasonic seal.

The packaging material of the present invention is filled with contents through its opening, and the opening is then heat-sealed to produce a product using the packaging material of the present invention. The uses of the packaging material are not particularly limited, but it can be suitably used for food packaging, medicines, sanitary products, cosmetics, electronic materials, building materials, industrial materials, etc. Contents to be filled include confectioneries such as rice crackers, bean snacks, nuts, biscuits and cookies, wafer snacks, marshmallows, pies, semi-dried cakes, candies, and snacks, staple foods such as bread, snack noodles, instant noodles, dried noodles, pasta, aseptically packaged cooked rice, porridge, porridge, packaged rice cakes, and cereal foods, pickles, boiled beans, natto, miso, frozen tofu, tofu, nametake mushrooms, konjac, wild vegetable products, jams, peanut cream, salads, frozen vegetables, and processed potato products, livestock products such as hams, bacon, sausages, processed chicken products, and corned beef, and fish hams and sausages. Examples of the foodstuffs include processed fish products such as fish paste, fish paste products, kamaboko, nori, tsukudani, bonito flakes, shiokara, smoked salmon, and spicy cod roe, fruit pulp such as peaches, mandarin oranges, pineapples, apples, pears, and cherries, vegetables such as corn, asparagus, mushrooms, onions, carrots, radishes, and potatoes, prepared foods such as frozen and chilled prepared foods such as hamburger steaks, meatballs, seafood fries, gyoza, and croquettes, dairy products such as butter, margarine, cheese, cream, instant creamy powder, and infant formula, liquid seasonings, retort curry, and pet food. They can also be used as packaging materials for cigarettes, disposable hand warmers, medicines, supplements, infusion packs, and vacuum insulation materials.

The present invention will be described more specifically with reference to examples. In the following, "parts" and "%" are all based on mass.
In the present invention, the weight average molecular weight (converted into polystyrene) was measured by gel permeation chromatography (GPC) using an HLC8220 system manufactured by Tosoh Corporation under the following conditions.
Separation column: Four columns of TSKgel GMHHR-N manufactured by Tosoh Corporation were used. Column temperature: 40° C. Mobile phase: Tetrahydrofuran manufactured by Wako Pure Chemical Industries, Ltd. Flow rate: 1.0 ml/min.
Sample concentration: 1.0% by weight. Sample injection amount: 100 microliters. Detector: differential refractometer.
The viscosity was measured at 25° C. using a Tokimec B-type viscometer.

(Preparation of polyvinyl butyral resin solution B1)
A polyvinyl butyral resin (weight average molecular weight 10,000, hydroxyl group content 15 mass%, glass transition point 60°C, acetyl group content 8 mass%) obtained by reacting polyvinyl alcohol with butylaldehyde was made into a 10% solution in isopropyl alcohol, and this was named polyvinyl butyral resin solution B1.

(Preparation of polyvinyl butyral resin solution B2)
A polyvinyl butyral resin (weight average molecular weight 20,000, hydroxyl group content 20 mass%, glass transition point 70°C, acetyl group content 4 mass%) obtained by reacting polyvinyl alcohol with butylaldehyde was made into a 10% solution in isopropyl alcohol, and this was named polyvinyl butyral resin B2.

(Synthesis Example 1: Polyurethane resin solution P1)
A four-neck flask equipped with a stirrer, a thermometer, a reflux condenser and a nitrogen gas inlet tube was charged with 233.38 parts of neopentyl glycol adipate diol (hydroxyl value: 37.4 mg KOH / g), 190.95 parts of polyethylene glycol (hydroxyl value: 112.2 mg KOH / g) and 89.49 parts of isophorone diisocyanate, and reacted for 10 hours at 90 ° C. under a nitrogen stream to produce a urethane prepolymer with an isocyanate group content of 2.09 mass%, and then 128.15 parts of ethyl acetate were added to this to obtain a uniform solution of the urethane prepolymer. Next, the urethane prepolymer solution was added to a mixture consisting of 23.87 parts of isophorone diamine, 0.30 parts of cyclohexylamine, 750.3 parts of ethyl acetate and 376.6 parts of isopropyl alcohol, and the mixture was stirred and reacted at 45 ° C. for 5 hours to obtain a polyurethane resin solution P1. The resulting polyurethane resin solution P1 had a resin solids concentration of 30.3% by mass, and the Mw of the resin solids was 54,000.

(Synthesis Example 2: Polyurethane resin solution P2)
A four-neck flask equipped with a stirrer, a thermometer, a reflux condenser and a nitrogen gas inlet tube was charged with 233.38 parts of neopentyl glycol adipate diol (hydroxyl value: 37.4 mg KOH / g), 41.18 parts of polyethylene glycol (hydroxyl value: 280.5 mg KOH / g) and 60.19 parts of isophorone diisocyanate, and reacted for 10 hours at 90 ° C. under a nitrogen stream to produce a urethane prepolymer with an isocyanate group content of 2.17% by mass, and then 83.7 parts of ethyl acetate were added to this to obtain a uniform solution of the urethane prepolymer. Next, the urethane prepolymer solution was added to a mixture consisting of 15.99 parts of isophorone diamine, 0.32 parts of cyclohexylamine, 489.7 parts of ethyl acetate and 245.7 parts of isopropyl alcohol, and the mixture was stirred and reacted at 45 ° C. for 5 hours to obtain a polyurethane resin solution P4. The resulting polyurethane resin solution P4 had a resin solids concentration of 30.3% by mass, and the Mw of the resin solids was 60,000.

(Synthesis Example 3: Polyurethane resin solution P3)
A four-neck flask equipped with a stirrer, a thermometer, a reflux condenser and a nitrogen gas inlet tube was charged with 240.65 parts of polyethylene glycol (hydroxyl value: 56.1 mgKOH/g) and 40.07 parts of isophorone diisocyanate, and reacted for 10 hours at 90 ° C. under a nitrogen stream to produce a urethane prepolymer with an isocyanate group content of 1.72% by mass, and then 70.2 parts of ethyl acetate was added to the mixture to obtain a uniform solution of the urethane prepolymer. Next, the urethane prepolymer solution was added to a mixture consisting of 10.65 parts of isophorone diamine, 0.22 parts of cyclohexylamine, 406.1 parts of ethyl acetate and 204.1 parts of isopropyl alcohol, and the mixture was stirred and reacted at 45 ° C. for 5 hours to obtain a polyurethane resin solution P3. The obtained polyurethane resin solution P3 had a resin solid concentration of 30.2% by mass and a resin solid Mw of 65,000.

(Synthesis Example 4: Polyurethane resin solution P4)
A four-neck flask equipped with a stirrer, a thermometer, a reflux condenser and a nitrogen gas inlet tube was charged with 240.65 parts of neopentyl glycol adipate diol (hydroxyl value: 36.1 mgKOH/g) and 40.07 parts of isophorone diisocyanate, and reacted under a nitrogen stream at 90°C for 10 hours to produce a urethane prepolymer with an isocyanate group content of 1.72% by mass, and then 70.2 parts of ethyl acetate was added to the mixture to obtain a uniform solution of the urethane prepolymer. Next, the urethane prepolymer solution was added to a mixture consisting of 10.87 parts of isophorone diamine, 0.22 parts of cyclohexylamine, 406.4 parts of ethyl acetate and 204.3 parts of isopropyl alcohol, and the mixture was stirred and reacted at 45°C for 5 hours to obtain a polyurethane resin solution P6. The obtained polyurethane resin solution P6 had a resin solids concentration of 30.1% by mass and a resin solids Mw of 58,000.

(Preparation of Cellulose Acetate Propionate Resin Solution Ca)
80 parts of a mixture of isopropyl alcohol/ethyl acetate/normal propyl acetate/methylcyclohexane (weight ratio of 25/25/13/10) was added to 20 parts of cellulose acetate propionate CAP482-0.5 (manufactured by Eastman Chemical Co.) and thoroughly mixed to prepare a cellulose ester resin solution Ca having a resin solid content concentration of 20% by mass.

(Preparation of Maleic Acid Resin Solution M)
A maleic acid resin solution M was prepared by mixing "SMA 3000P" manufactured by Tomoe Engineering Co., Ltd. in a mixture of 25% IPA, 25% ethyl acetate, and 50% SMA 3000P to prepare a 50% solids solution, which was then thoroughly stirred.
(Preparation of vinyl chloride/vinyl acetate copolymer resin solution)
A hydroxyl group-containing vinyl chloride-vinyl acetate copolymer resin (resin monomer composition by weight: vinyl chloride/vinyl acetate/vinyl alcohol=92/3/5, hydroxyl value (mg KOH)=64) was made into a 10% solution in ethyl acetate, and this was designated as vinyl chloride-vinyl acetate resin solution V.

<Preparation of second liquid ink composition>
(Preparation Example I-1)
A mixture of 30 parts of polyurethane resin solution P1, 25 parts of polyvinyl butyral resin B1 (solid content 10%), 1 part of maleic acid resin solution M, 3 parts of cellulose acetate propionate resin solution Ca, 10 parts of a phthalocyanine blue pigment (FASTGEN Blue LA5380: manufactured by DIC Corporation), and 31 parts of ethyl acetate, totaling 100 parts, was kneaded using a Dynomill (manufactured by Willy & Bachofenon) to prepare a liquid ink of the present invention.

(Preparation Examples I-2 to I-9, and Comparative Preparation Examples I-11 to I-12)
For Preparation Examples I2 to I-9 and Comparative Preparation Examples I-11 to I-12, second liquid inks were produced using the formulations shown in Tables 1 and 2 in the same manner as in Preparation Example I-1.

<Preparation of first liquid ink composition>
(Preparation Example II-1)
A mixture of 30 parts of polyurethane resin solution P1, 1 part of maleic acid resin solution M, 3 parts of cellulose acetate propionate resin solution Ca, 36 parts of titanium oxide JR-780 (manufactured by Teika Co., Ltd.), and 30 parts of ethyl acetate, totaling 100 parts, was kneaded using a Dynomill (manufactured by Willy & Bachofenon Co., Ltd.) to prepare a liquid ink.

(Preparation Examples II-2 to II-3, and Comparative Preparation Examples II-11 to II-12)
For Preparation Examples II-2 to II-3 and Comparative Preparation Examples II-11 to II-12, first liquid inks were produced according to the formulations shown in Table 3 and in the same manner as in Preparation Example II-1.

<Creating printed matter>
Example 1
The viscosity of the liquid ink of Preparation Example II-1 was adjusted to 16 seconds (25°C) with ethyl acetate using a Zahn cup #3 (manufactured by Rigo Co., Ltd.), and the ink was applied to a film using a gravure proofing machine equipped with a gravure plate having a plate depth of 35 µm to form a white printing layer.

Next, the viscosity of the liquid ink of Preparation Example I-1 was adjusted to 16 seconds (25°C) with ethyl acetate using a Zahn cup #3 (manufactured by Rigo Co., Ltd.), and a color printing layer was formed on top of the prepared white printing layer using a gravure proofing machine equipped with a gravure plate with a plate depth of 35 μm, thereby producing a multilayer print.

(Examples 2 to 11, Comparative Examples 1 to 4)
For Examples 2 to 11 and Comparative Examples 1 to 4, printed matter was produced using the liquid inks shown in Table 3 in the same manner as in Example 1.

<Evaluation>
The liquid inks and printed matter prepared were evaluated as follows.
(Base liquidity)
The viscosity of the first liquid ink and the second liquid ink described in Preparation Example I-1 to Preparation Example II-1 was measured at rotation speeds of 6 rpm and 60 rpm using a Brookfield viscometer. The viscosity measured at 6 rpm was divided by the viscosity measured at 60 rpm to obtain the TI value. If the TI value is less than 3.0, the ink is usable for practical use.

○: TI value is less than 1.5 △: TI value is 1.5 or more but less than 3.0 ×: TI value is 3.0 or more
(viscosity)
The viscosity of the first liquid ink and the second liquid ink described in Preparation Example I-1 to Preparation Example II-1 was measured using a Zahn Cup #4 (manufactured by Rigo Co., Ltd.). If the viscosity was 30 seconds or less, the ink was usable for practical use.

(Storage stability)
The first liquid ink and the second liquid ink described in Preparation Example I-1 to Preparation Example II-1 were allowed to stand at 25° C. for one week, and then the degree of separation and precipitation was evaluated.
<Separation> Appearance Evaluation ◯: No separation was observed at all.
△: Some separation is observed in the upper layer. As a guideline, the thickness of the separated layer is 5 mm or less.
×: Clear separation is observed in the upper layer. As a guideline, the thickness of the separated layer is 5 mm or more.
<Sedimentation> Gently scrape the bottom of the container containing the ink with a spatula.
A: No precipitation is observed.
△: A small amount of sediment is observed at the bottom. (A small amount of sediment is observed at the tip of the spatula.)
×: A lot of sediment is found at the bottom. (A lot of sediment can be scraped off with a spatula.)

(Boiling resistance)
A linear low density polyethylene film (LLDPE film: Mitsui Chemicals Tohcello TUX-HC, thickness 60 μm) was laminated on the printed matter of Examples 1 to 11 and Comparative Examples 1 to 4 using a urethane-based dry laminating adhesive DIC Dry LX-500/KW-75 (DIC) by a dry laminating machine (DIC Engineering), and aged at 40° C. for 3 days to obtain a laminate. The obtained laminate was made into a pouch of 120 mm x 120 mm in size, and filled and sealed with 70 g of a pseudo food containing vinegar, salad oil, and meat sauce in a weight ratio of 1:1:1 as the contents. The pouch was boiled at 98° C. for 60 minutes, the contents were removed, the pouch was washed with water, and the bag was cut into a width of 15 mm and a T-peel test was performed at a pulling speed of 300 mm/min.

In addition, in the boil resistance test, a Ny film with one side subjected to corona treatment was used as the film for the printed matter, and the printed matter was produced by printing on the corona-treated side.

The printed matter produced had the following order from the Ny film side of the substrate: Ny substrate (F)/printed ink layer/adhesive layer (Ad)/LLDPE film.
◎: 3.5 N/15 mm or more, sufficient strength. ◯: 3.0 N/15 mm or more but less than 3.5 N/15 mm, practical range. △: 2.0 N/15 mm or more but less than 3.0 N/15 mm, slightly insufficient strength. ×: Less than 2.0 N/15 mm, insufficient strength.

In addition, the appearance of the resulting pouch after boiling treatment was evaluated.
Good: No delamination or blistering observed.
△: Slight delamination or blistering is observed in some parts of the pouch.
×: Clear delamination or blisters are observed throughout the pouch.

(Retort resistance)
The printed matter of Examples 1 to 11 and Comparative Examples 1 to 4 was laminated with aluminum foil and non-oriented polypropylene film (hereinafter referred to as R-CPP: ZK-75 50 μm, manufactured by Toray Synthetic Films Co., Ltd.) using a dry laminating machine (manufactured by DIC Engineering Co., Ltd.) with a urethane-based dry laminating adhesive DIC Dry LX-703VL/KR-90 (manufactured by DIC), and aged at 40° C. for 3 days to obtain a laminate. The obtained laminate was made into a pouch having a size of 120 mm x 120 mm, and 70 g of a pseudo food containing vinegar, salad oil, and meat sauce in a weight ratio of 1:1:1 was filled and sealed as the contents. The produced pouch was subjected to steam retort sterilization at 135° C. for 30 minutes, after which the contents were removed and the pouch was washed with water, and the bag was cut into a width of 15 mm and subjected to a T-peel test at a pulling speed of 300 mm/min.

In the retort resistance test, a biaxially oriented polyester film (PET film) with one side subjected to a corona treatment was used as the film for the printed matter, and the printed matter was produced by printing on the corona-treated side.

The printed matter produced had the following order from the PET film side of the substrate: PET substrate (F) / printing ink layer / adhesive layer (Ad1) / aluminum foil (AL) / adhesive (Ad2) / R-CPP film. A biaxially stretched polyester film (PET film: Toyobo Co., Ltd. E-5100, thickness 12 μm) was used.
The evaluation results in the table are as follows.

◎: 3.5 N/15 mm or more, sufficient strength. ◯: 3.0 N/15 mm or more but less than 3.5 N/15 mm, practical range. △: 2.0 N/15 mm or more but less than 3.0 N/15 mm, slightly insufficient strength. ×: Less than 2.0 N/15 mm, insufficient strength.

In addition, the appearance of the resulting pouch after retort treatment was evaluated.
Good: No delamination or blistering observed.
△: Slight delamination or blistering is observed in some parts of the pouch.
×: Clear delamination or blisters are observed throughout the pouch.

(Leveling ability)
The densities of 100% and 50% dots of the color print layer in the printed matter were measured using a reflection densitometer. The leveling ability was evaluated based on the density ratio obtained by dividing the 50% density by the 100% density, according to the following criteria.

A: Concentration ratio is 0.36 or more B: Concentration ratio is 0.3 or more and less than 0.36 C: Concentration ratio is less than 0.3 The results are shown in the table below. Note that in Comparative Examples 1 and 3, the viscosity and storage stability were outside the practical range, and the boil resistance, retort resistance, and leveling properties could not be evaluated.

From the above results, it was found that by forming a laminate in which the first printed layer having a white pigment does not contain polyvinyl butyral resin and the second printed layer not using a white pigment uses polyvinyl butyral resin, a laminate having excellent laminate strength can be obtained without impairing the basic properties of the ink, such as dispersibility, fluidity, and stability. The laminates of Examples 1 to 11 are also excellent in environmental safety because they do not contain chlorine-based resin like Comparative Example 4, and furthermore, they are found to have superior leveling properties compared to Comparative Example 4. The reason why Examples 1 to 11 have superior leveling properties compared to Comparative Example 4 is unclear, but one reason is thought to be that the ink containing butyral has a smaller contact angle with the film and is easier to wet and spread than the ink containing vinyl chloride-vinyl acetate copolymer resin.

Claims (8)

A first printed layer not containing a polyvinyl butyral resin and a second printed layer containing a polyvinyl butyral resin and a polyurethane resin are provided on a film substrate,
The film base material, the first printed layer, and the second printed layer are provided in this order, or the film base material, the second printed layer, and the first printed layer are provided in this order,
The first printed layer contains 20 to 60 mass % of titanium oxide as a white pigment. The printed matter according to claim 1, wherein neither the first printed layer nor the second printed layer contains a chlorine-based resin. The printed matter according to claim 1 or 2, wherein the polyvinyl butyral resin has a number average molecular weight of 5,000 to 60,000, a glass transition point of 50 to 120°C, and a hydroxyl group content of 10 to 30% by mass. The printed matter according to claim 1 or 2, wherein the second printed layer further contains at least one resin selected from maleic acid resin, cellulose-based resin, polyester resin, acrylic resin, and polyamide resin. The printed matter according to claim 1 or 2, wherein the second printed layer contains 5 to 100 mass % of the polyvinyl butyral resin relative to the total amount of resin contained in the second printed layer. The printed matter according to claim 1 or 2, wherein the first printed layer contains at least one resin selected from polyurethane resin, maleic acid resin, cellulose resin, polyester resin, acrylic resin, and polyamide resin. A laminate having the printed matter according to claim 1. A laminate comprising the printed matter according to claim 1, an adhesive layer, and a sealant film.