JP7199630B2 - Laminate and its manufacturing method - Google Patents

Description

TECHNICAL FIELD The present invention relates to a laminate produced using a water-based inkjet ink and a laminate adhesive composition, and a method for producing the same.

Flexible packaging materials used for packages of foods, medicines, cosmetics, etc. are laminates obtained by laminating plastic films together and/or plastic films and metallized films or metal foils. In general, a laminate that can be used as a flexible packaging material or the like is obtained by laminating a separately prepared material such as a plastic film, a metal-deposited film, or a metal foil to a plastic film on which a printed layer has been formed in advance. This processing method is called "laminating". Further, in order to form a printed layer in a laminate, conventionally, gravure printing or flexographic printing is performed on a plastic film (hereinafter also simply referred to as "film substrate"). Both gravure printing and flexographic printing are printing methods in which ink is transferred to a plate prepared in advance, and are suitable for high-speed printing and mass production.

Under these circumstances, in recent years, in the market for flexible packaging materials, along with the change and diversification of consumer needs, there has been an increase in the variety of products and a shortening of the product cycle. In addition, in consideration of environmental issues and occupational safety, water-based inks are also being used (see, for example, Patent Document 1). In the case of , it is often not profitable. Also, since it takes time to make a plate, it was difficult to meet a short delivery date.

In contrast to the above printing methods, digital printing does not require a plate, so it is possible to reduce costs and respond to short delivery times. progressing to The inkjet printing method, which is a type of digital printing method, involves ejecting and landing fine droplets of ink from an inkjet head onto a recording medium to produce images and characters (hereinafter collectively referred to as "printed matter") on the recording medium. ). Compared to other digital printing methods, it is superior in terms of size and cost of printing equipment, running cost during printing, ease of full-color printing, etc. In recent years, it has been used for industrial printing applications.

There are many types of inks used in inkjet printing, including oil-based, solvent-based, active energy ray-curable, and water-based inks. So far, solvent-based and active energy ray-curable inks have been used for industrial printing applications. However, in recent years, from the point of view of considering and dealing with harmfulness to the environment and people, as in the case of gravure printing and flexographic printing, it is desired to use water-based ink.

On the other hand, when inkjet printing is used to produce flexible packaging materials, image formation on the film substrate is essential as described above. Existing water-based inks used in inkjet printing (hereinafter simply referred to as "inkjet inks") are used for image formation on highly permeable substrates such as plain paper and special paper (e.g., glossy photo paper). When printing on a non-permeable substrate such as a film substrate, the ink droplets after landing do not dry due to permeation and absorption, which impairs the print quality. Problems such as poor adhesion and occurrence of blocking occur.

For example, Patent Document 2 discloses a water-based inkjet ink in which a resin having specific properties and an organic solvent having a specific structure are used in combination. There is a description that it can be used suitably for However, as will be described later, when the present inventors evaluated the ink using the resin specifically described in the examples of Patent Document 2, it was found that the ejection stability was inferior. In recent years, in order to meet the market demand for the above-mentioned application development, studies have been made to increase the resolution of printed matter by miniaturizing the ink droplets ejected from the inkjet head and increasing the driving frequency of the inkjet head. Therefore, it can be said that the improvement of ejection stability is an essential issue.

In addition, if the adhesion to the film substrate is insufficient, the ink film may be peeled off due to rubbing or the like, resulting in a problem that the desired printed image cannot be obtained. Furthermore, when another film is laminated (laminated) via an adhesive (laminate adhesive), the adhesive strength between the layers that make up the laminate cannot be obtained, and a peeling phenomenon (delamination) occurs between the laminates. ) may occur. In particular, in the case of soft packaging materials, after being shaped into a packaging material, it may undergo a process after heat sterilization such as boiling or retorting. Defects will occur.

The present applicant has previously proposed a water-based inkjet ink containing a (styrene) (meth)acrylic resin having a specific composition, which is excellent in ejection stability and print quality on impermeable substrates (see Patent Document 3). . However, with the ink described above, there is a risk that the laminate strength of the printed material may be insufficient, and in consideration of the development of flexible packaging materials, the situation requires improvement.

By the way, in lamination, conventionally, solvent lamination adhesive compositions and non-solvent lamination adhesives (hereinafter referred to as "laminate adhesives" or simply "adhesives"), which are bonding methods based on hydroxyl group/isocyanate curing systems, have been used. ) is the mainstream. In recent years, in the market for flexible packaging materials, consumer needs have diversified and products have become more diverse. In order to respond to these trends, research has been conducted on high adhesive strength between layers that make up laminated laminates. is being done. For example, Patent Document 4 discloses a multilayer composition using an isocyanate prepolymer adhesive layer and a printing layer containing a hyperbranched polyester. However, the printing layer disclosed in Patent Document 4 is a flexographic printing method, not an inkjet printing method.

Further, Patent Document 5 discloses a laminate adhesive containing a polyol component and an isocyanate component composed of two kinds of isocyanate compounds. Further, Patent Document 6 discloses a laminate adhesive containing a polyol component and an isocyanate component essentially comprising isophorone diisocyanate. However, the laminating adhesives disclosed in Patent Documents 5 and 6 have been studied only for lamination of plastic films, and for lamination with a printed layer (ink layer) on a film substrate, Not rated.

As described above, a method for obtaining a laminate having excellent ejection stability and post-processing functions suitable for flexible packaging materials in printing on a non-penetrating base material by a water-based inkjet ink printing method has been found so far. It was not.

JP-A-5-171091 JP 2013-159619 A Japanese Patent Application Laid-Open No. 2018-203802 JP 2016-532578 A JP-A-8-60131 JP-A-2006-57089

The present invention has been made to solve the above problems, and its object is to provide good print quality without color unevenness even in printing on impermeable substrates such as OPP film, PET film, and nylon film. It is an object of the present invention to provide a laminate which is excellent in ejection stability from nozzles of an ink jet head and which maintains good print image quality and excellent adhesive strength even after lamination.

In order to solve the above problems, as a result of extensive studies by the present inventors, a water-based inkjet ink containing a binder resin having a specific ethylenically unsaturated monomer as a structural unit, and a specific structure and a specific range The inventors have found that the above problems can be satisfactorily solved by a laminate produced using an adhesive composition containing a polyol component having a number average molecular weight, and have completed the present invention.

That is, the present invention provides a method for producing a laminate having a transparent substrate 1, an ink layer (II), an adhesive layer (III), and a substrate 4 in this order, comprising the following steps (1) to It relates to a method for manufacturing a laminate including (4).
(1) A step of printing a water-based inkjet ink (A) on a transparent substrate 1 by an inkjet printing method and then drying to obtain an ink layer (II) having a thickness of 0.2 to 20 μm.
However, the water-based inkjet ink (A) contains a binder resin (B), a pigment , a water-soluble organic solvent, and a surfactant ,
The binder resin (B) has a hydroxyl value of 3 to 50 mgKOH/ g, an acid value of 10 to 60 mgKOH/g, a weight average molecular weight of 5,000 to 45,000, and a glass transition temperature (Tg) of 35 to 110 ° C., and the binder resin (B) is derived from a structural unit derived from an ethylenically unsaturated monomer (b1) containing an acid group, and an ethylenically unsaturated monomer (b2) containing a hydroxyl group. and a water-based resin, and the content of the binder resin (B) is 1 to 20% by mass, in terms of non-volatile content, relative to the total amount of the water-based inkjet ink (A). ,
When the water-based inkjet ink (A) is other than white ink, the content of the pigment is 2 to 20% by mass with respect to the total amount of the water-based inkjet ink (A), and the water-based inkjet ink (A) is white. In the case of ink, the content of the pigment is 5 to 40% by mass with respect to the total amount of the water-based inkjet ink (A),
The content of the water-soluble organic solvent is 3 to 40% by mass with respect to the total amount of the water-based inkjet ink (A),
The content of the surfactant is 0.05 to 5.0% by mass with respect to the total amount of the water-based inkjet ink (A).
(2) A step of forming an adhesive layer precursor comprising the laminate adhesive composition (J) on the ink layer (II) and/or the substrate 4 .
However, the laminate adhesive composition (J) contains a polyol component (M) and an isocyanate component (K), and the number of moles of isocyanate groups in the isocyanate component (K) and the number of moles of the polyol component (M) The NCO/OH ratio, which is the ratio to the number of moles of hydroxyl groups, is in the range of 1.0 to 3.0, the polyol component (M) has a number average molecular weight of 500 to 3,200, polyester polyol, Alternatively, it contains a polyether polyol .
(3) A step of superimposing the ink layer (II) and the substrate 4 through the precursor of the adhesive layer.
(4) A step of curing the precursor of the adhesive layer to form the adhesive layer (III).

The present invention also relates to a method for producing the laminate, wherein the binder resin (B) has a hydroxyl value of 10 to 45 mgKOH/g.

The present invention also relates to a method for producing the laminate, wherein the ratio of the polyol having a molecular weight of 500 to 3,200 to the total polyol component (M) is 25% by mass or more.

The present invention also relates to a method for producing the laminate, wherein the isocyanate component (K) contains a urethane prepolymer compound obtained by reacting an aromatic isocyanate and a polyether polyol.

According to the present invention, even when printing on non-permeable substrates such as OPP films, PET films, and nylon films, the print quality is good without color unevenness, and the ejection stability from the nozzles of the inkjet head is excellent. It is possible to obtain a laminate that maintains good print quality and excellent adhesive strength even after lamination, boiling, retorting, or other heat sterilization treatments.

FIG. 1 is a schematic diagram showing an example of a cross-section of a complete solid printed matter used for evaluation of color unevenness, inkjet dischargeability, adhesive strength, and the like.

Hereinafter, a preferred embodiment of the laminate (hereinafter also simply referred to as "this embodiment") will be described.

The ink layer (II) of the laminate of the present embodiment is a layer composed of a dried film of water-based inkjet ink (A) containing a binder resin (B) and a pigment. As is done in Patent Documents 3 and 4, it is common to add a binder resin to the ink. In general, increasing the weight-average molecular weight of the binder resin may increase the adhesive strength after lamination. However, resins with a large weight average molecular weight may significantly deteriorate ink ejection stability. In particular, when used together with a water-soluble organic solvent with a low boiling point in order to improve drying performance on impermeable substrates, the ink viscosity at the air-liquid interface of the nozzle increases sharply, and the nozzle clogs due to precipitation of the binder resin. , and there is a high possibility of deteriorating the ejection stability.

On the other hand, the adhesive layer (III) of the laminate of the present embodiment is a layer composed of a cured film of a laminate adhesive composition (J) containing a polyol component (M) and an isocyanate component (K). By increasing the molecular weights of the polyol component (M) and the isocyanate component (K), there is a possibility that the adhesive strength after lamination processing will increase, but the crosslinking density will not increase during the reaction, resulting in poor curing and the ink layer ( II) may degrade the print quality. In addition, the adhesive becomes more viscous and tends to be unevenly coated, resulting in poor appearance after the films are pasted together, de-lamination caused by unevenness, and deterioration of the content resistance of flexible packaging materials. Cheap.

Therefore, as a result of intensive studies by the present inventors, it was found that the binder resin (B) of the water-based inkjet ink (A) has a hydroxyl value of 3 mgKOH/g or more, contains a water-based resin having an acid group and a hydroxyl group, and has a laminate. The ratio of the number of moles of isocyanate groups in the isocyanate component (K) of the adhesive composition (J) to the number of moles of hydroxyl groups in the polyol component (M) is within a specific range, and has a specific structure and a specific number average It has been found that by including a polyol component having a molecular weight, excellent adhesive strength after lamination can be obtained in addition to good inkjet dischargeability and excellent print image quality. Although the details are not clear, for example, the following mechanism is considered.

First, the binder resin (B) contained in the inkjet ink (A) of this embodiment contains a water-based resin. By making the binder resin water-based, the ejection stability of the inkjet ink can be ensured. In order to render the resin water-based, it contains a structure derived from an ethylenically unsaturated monomer (b1) containing an acid group. It should be noted that the introduction of ethylene oxide groups is also known as a method for making resins water-based, but in the present invention, by using acid groups, the adhesiveness to film substrates and the adhesive strength after lamination can also be improved. This effect is obtained.

In addition, the binder resin (B) contains a structure derived from the hydroxyl-containing ethylenically unsaturated monomer (b2). The hydroxyl group derived from the ethylenically unsaturated monomer (b2) reacts with the isocyanate component (K) of the lamination adhesive composition (J) present in the adhesive layer (III) to improve adhesive strength. In this way, the components of the ink layer (II) and the adhesive layer (III) react to increase the cohesive force between the layers, resulting in a laminate with strong adhesion.

On the other hand, NCO, which is the ratio of the number of moles of isocyanate groups (hereinafter also simply referred to as "NCO groups") in the isocyanate component (K) of the laminate adhesive composition (J) to the number of moles of hydroxyl groups in the polyol component (M) The /OH ratio ranges from 1.0 to 3.0. By setting the NCO/OH ratio to 1.0 or more, the reaction with the hydroxyl group derived from the ethylenically unsaturated monomer (b2) of the water-based inkjet ink (A) is facilitated, and the cross-linking reaction between layers is promoted. be done. Moreover, it is thought that by making it 3.0 or less, excessive NCO groups are not left, poor curing is suppressed, and high adhesive strength can be obtained.

The number average molecular weight (Mn) of the polyol component (M) is 500-3,200. When the number average molecular weight is more than 3,200, the reaction of the isocyanate component (K) with the NCO group is slow, and the penetration of the isocyanate component (K) into the ink layer (II) proceeds excessively, resulting in an adhesive layer ( Insufficient curing of III) occurs, and the adhesive strength after lamination deteriorates. When the number average molecular weight is less than 500, the reaction of the isocyanate component (K) with the NCO group proceeds positively, resulting in a hard adhesive layer (III) but lacking flexibility, and the isocyanate component (K) is It is consumed only for the reaction with the polyol component (M), and the reaction with the hydroxyl group derived from the ethylenically unsaturated monomer (b2) contained in the binder resin (B) of the water-based ink (A) is poor, and the ink layer (II ) and the adhesive layer (III) is difficult to obtain, and the adhesive strength as a laminate is lowered. By setting the number average molecular weight of the polyol component (M) to a specific range, the reaction with the NCO group of the isocyanate component (K) is not biased, and the laminate adhesive composition ( J) has a high cross-linking density, resulting in a cured film that is both strong and flexible, and provides a cohesive force between the ink layer (II) and the adhesive layer (III), resulting in a strong adhesive strength as a laminate. can get.

Further, the polyol component (M) includes a polyester polyol or a polyether polyol (both of which have terminal hydroxyl groups). Polyester polyols and polyether polyols have excellent organic solvent resistance due to their structures, have high affinity with the binder resin (B) of the water-based ink (A), and are used in the ink layer of the laminate adhesive composition (J) ( It has excellent coating suitability for II), and it is possible to form a uniform coating film without unevenness. As a result, a laminate having a better appearance can be obtained without impairing the printed image. Furthermore, in order to form a uniform and flexible coating film without unevenness, the ink layer (II) and the adhesive layer (III) have high cohesive strength, distortion due to external stress is small, and adhesive strength is improved. A strong laminate can be obtained.

As described above, there is no color unevenness, the print quality is good, the inkjet ejection is stable, the adhesion between each layer is excellent, and even after lamination, the print quality is good and the adhesion is excellent In order to obtain a laminate that maintains the force, the configuration of the laminate of this embodiment is essential.

Subsequently, each component constituting the laminate of the present embodiment will be described in detail below.

<Ink layer (II), aqueous inkjet ink (A)>
Next, the ink layer (II) constituting the laminate of this embodiment will be described. The ink layer (II) is a layer composed of a dried film of a water-based inkjet ink (A) (hereinafter also simply referred to as "aqueous ink"), and the water-based ink (A) comprises a liquid medium containing water and a binder resin. (B) and a pigment, wherein the hydroxyl value of the binder resin (B) is 3 mgKOH/g or more, and as structural units, an ethylenically unsaturated monomer (b1) containing an acid group, and a hydroxyl group containing ethylenically unsaturated monomer (b2) containing water-modified resin.

<Binder resin (B)>
The binder resin (B) contained in the water-based ink (A) of the present embodiment has a hydroxyl value of 3 mgKOH/g or more, and contains, as structural units, an ethylenically unsaturated monomer (b1) containing an acid group, and It includes a water-modified resin containing an ethylenically unsaturated monomer (b2) containing a hydroxyl group.

The "binder resin" in the present invention is a main component that constitutes the ink layer (hereinafter also referred to as a printing layer), and its main purpose is a resin used for bonding to the base material and the laminate adhesive. be. As will be described later, the water-based ink used in the present invention may contain a pigment dispersing resin, which is a resin used mainly for stabilizing the dispersion of the pigment. Therefore, the pigment dispersing resin and the binder resin are distinguished by their adsorption rate to the pigment. That is, in a pigment dispersion containing a pigment, a resin, and an aqueous medium, wherein the pigment concentration is 5% by mass and the amount of water is 98% by mass or more based on the total amount of the aqueous medium, the pigment A resin having an adsorption rate of 35% by mass or more is determined as a pigment dispersion resin, and a resin having an adsorption rate of less than 35% by mass is determined as a binder resin.

The pigment dispersion used for the measurement of the adsorption rate is, for example, by the method described in the production example of the pigment dispersion C described later, after producing a high-concentration pigment dispersion having a pigment concentration of 20% by mass, the pigment It can be prepared by diluting with water until the concentration reaches 5% by mass. The adsorption rate is obtained by, for example, subjecting the pigment dispersion to ultracentrifugation (for example, 30,000 rpm for 4 hours), then measuring the amount of resin contained in the supernatant, and calculating the following formula (1 ) can be calculated using

Formula (1): Adsorption rate (%) = (WR1-WR2) x 100/WR1

However, in the above formula (1), WR1 represents the amount of resin contained in the pigment dispersion before ultracentrifugation, and WR2 represents the amount of resin contained in the supernatant.

Water-soluble resins and hydrosols and emulsions, which are water-insoluble resins, are generally known as forms of resins. Here, the term “water-soluble resin” refers to a target resin that is transparent to the naked eye when mixed with water at 25° C. and 1% by mass. Further, "hydrosol" refers to a form in which acidic and/or basic functional groups present in a resin are neutralized and dispersed in a dispersion medium, and "emulsion" refers to an emulsifier adsorbed on the surface of fine resin particles. and dispersed in a dispersion medium. This embodiment is characterized by using a water-soluble resin, that is, a water-soluble resin or a hydrosol, as the binder resin (B). At least part of these resins swells and/or dissolves in the aqueous medium in the ink, and is preferably selected from the viewpoint of suppressing precipitation at the air-liquid interface of the nozzle and improving ejection stability. be.

In addition, random copolymers, alternating copolymers, block copolymers, graft copolymers, and the like are known as the arrangement of monomers constituting a copolymer. Any of the above forms can be used.

The binder resin (B) used in the present embodiment contains, as a structural unit, a structure derived from an ethylenically unsaturated monomer (b1) containing an acid group. By including an acid group, it is possible to improve the adhesiveness to the film substrate and the adhesive strength after lamination. The "acid group" includes a carboxylic acid (carboxyl) group, a sulfonic acid group, a phosphonic acid group, and the like, and any of them may be selected in the present invention. Among them, a carboxyl group is preferably selected from the viewpoint of improving ejection stability.

As the ethylenically unsaturated monomer (b1) containing an acid group, known substances can be used. Specifically, acrylic acid, methacrylic acid, carboxymethyl (meth)acrylate, carboxyethyl (meth)acrylate, acryloyloxyethyl succinic acid, methacryloyloxyethyl succinic acid, acryloyloxyethyl phthalate, methacryloyloxyethyl phthalate, acryloyl Oxyisobutyric acid, methacryloyloxyisobutyric acid, 2-sulfoethyl (meth)acrylate, acryloyloxyethylphosphonic acid, methacryloyloxyethylphosphonic acid, 2-(phosphonooxy)ethyl (meth)acrylate, vinylsulfonic acid, styrenecarboxylic acid, styrenesulfone acid, styrene phosphonic acid and the like. These acid group-containing ethylenically unsaturated monomers (a1) can be used singly or in combination. In addition, in this specification, "(meth)acrylate" represents at least one selected from "acrylate" and "methacrylate".

The acid value of the binder resin (B) used in the present embodiment is preferably 10 to 60 mgKOH/g, more preferably 25 to 45 mgKOH, from the viewpoint of improving ejection stability and adhesive strength after lamination. /g.

As used herein, the term "acid value" means the number of milligrams (mgKOH/g) of potassium hydroxide required to neutralize acidic components contained in 1 g of sample. The acid value of the resin may be calculated from each structural unit (monomer) constituting the resin, or may be measured experimentally. As an example of an experimental measurement method, a sample solution is titrated with an ethanol solution of potassium hydroxide (0.1 mol/L) using a potentiometric automatic titrator AT-710S manufactured by Kyoto Electronics Industry Co., Ltd. After the titration is completed, the acid value is calculated from the amount of the ethanol solution added until reaching the end point.

In addition, the binder resin (B) used in the present embodiment has a structure derived from an ethylenically unsaturated monomer (b2) containing a hydroxyl group as a constituent component in order to improve the adhesive strength of the ejection stability and the degree of lamination. include. As described above, the hydroxyl group in the monomer (b2) can form a chemical bond with the polar group on the film substrate or the isocyanate component (K) present in the adhesive layer (III), and after lamination. improves adhesion. In this way, the components of the film substrate and the ink layer (II) and the ink layer (II) and the adhesive layer (III) react to increase the cohesive force between the layers, resulting in a laminate with strong adhesion. be done. In addition, the use of the lamination adhesive composition (J), which will be described later, promotes the formation of a crosslinked structure with the hydroxyl groups, making it possible to obtain a very strong laminate.

As the hydroxyl group-containing ethylenically unsaturated monomer (b2), known substances can be used. Specific examples include hydroxyethyl methacrylate, hydroxyethyl acrylate, 4-hydroxybutyl acrylate and the like. These hydroxyl group-containing ethylenically unsaturated monomers (b2) can be used singly or in combination.

The hydroxyl value of the resin (B) used in the present invention is 3 mgKOH/g or more, and more preferably 5 from the viewpoint of improving ejection stability (initial ejection property and standby ejection property), drying property, and laminate strength. to 50 mgKOH/g, more preferably 10 to 45 mgKOH/g.

As used herein, the term "hydroxyl value" means the number of milligrams (mgKOH/g) of potassium hydroxide required to neutralize the acetic acid required to acetylate 1 g of sample. Similar to the acid value, the hydroxyl value may be calculated from each constituent unit (monomer) constituting the resin, or may be measured experimentally. An example of an experimental measurement method is to add an acetylation reagent (25 mass % pyridine solution of acetic anhydride) to a sample, acetylate the sample by heating, allow to cool, and add water to hydrolyze the acetic anhydride. do. Thereafter, ethanol is added as a solvent, and the sample solution is titrated with an ethanol solution of potassium hydroxide (0.5 mol/L) using a potentiometric automatic titrator similar to that for the acid value. After the titration is completed, the hydroxyl value is calculated from the amount of the ethanol solution added until reaching the end point.

The binder resin (B) used in the present invention is a structural unit other than the structure derived from the ethylenically unsaturated monomer (b1) containing an acid group and the structure derived from the ethylenically unsaturated monomer (b2) containing a hydroxyl group. (hereinafter also referred to as "other structural units") can be included one or more. When the binder resin (B) is (meth)acrylic or styrene (meth)acrylic, ethylenically unsaturated monomers forming other structural units include, for example, styrene, o-methylstyrene, m -methylstyrene, p-methylstyrene, α-methylstyrene, p-ethylstyrene, 2,4-dimethylstyrene, pn-butylstyrene, p-tert-butylstyrene, pn-hexylstyrene, p-methoxy Styrenic monomers such as styrene and p-phenylstyrene;
methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, isobutyl (meth) acrylate, pentyl (meth) acrylate, hexyl (meth) acrylate, octyl (meth) acrylate, 2- Ethylhexyl (meth)acrylate, nonyl (meth)acrylate, decyl (meth)acrylate, lauryl (meth)acrylate, myristyl (meth)acrylate, cetyl (meth)acrylate, stearyl (meth)acrylate, behenyl (meth)acrylate, tetratria Alkyl group-containing (meth)acrylic monomers such as kontanoyl (meth)acrylate and hexatriacontanoyl (meth)acrylate;
(Poly) ethylene glycol mono (meth) acrylate, (poly) propylene glycol mono (meth) acrylate, (poly) butylene glycol mono (meth) acrylate, (poly) (ethylene glycol-propylene glycol) mono (meth) acrylate, ( Poly)ethylene glycol mono(meth)acrylate monomethyl ether, (poly)ethylene glycol mono(meth)acrylate monobutyl ether, (poly)ethylene glycol mono(meth)acrylate monooctyl ether, (poly)ethylene glycol mono(meth)acrylate mono Alkylene oxide chains such as benzyl ether, (poly)ethylene glycol mono(meth)acrylate monophenyl ether, (poly)ethylene glycol mono(meth)acrylate monohexadecyl ether, (poly)ethylene glycol mono(meth)acrylate monooctadecyl ether containing (meth)acrylic monomer;
aromatic ring-containing (meth)acrylic monomers such as phenyl (meth)acrylate, benzyl (meth)acrylate, phenoxyethyl (meth)acrylate;
dimethylaminoethyl (meth)acrylate, amino group-containing (meth)acrylic monomers such as diethylaminoethyl (meth)acrylate;
Polyfunctionality such as diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, etc. (meth)acrylic monomer; and the like. In addition, "(meth)acryl" represents at least one selected from "acryl" and "methacryl".

Among the ethylenically unsaturated monomers forming the other structural units exemplified above, monomers having an aromatic ring structure are preferably selected from the viewpoint of obtaining an ink with excellent ejection stability. Moreover, a styrene-based monomer is particularly preferably selected because the weight average molecular weight and the glass transition temperature are easily kept within the above ranges, and the effects of the present invention are favorably exhibited.

As described above, the binder resin (B) contains an ethylenically unsaturated monomer as a structural unit. Therefore, (meth)acrylic and styrene (meth)acrylic resins are preferably used as the resin (B). In particular, it is preferable to use a styrene (meth)acrylic resin from the viewpoint of ensuring ejection stability from nozzles of an inkjet head.

The water-based ink used in the present invention may contain only the binder resin (B), or may contain a resin that does not correspond to the binder resin (B). In this case, urethane-based, vinyl chloride-based, polyolefin-based resins, etc. can be used as resins that do not correspond to the binder resin (B). In addition, the resin that does not correspond to the binder resin (B) may be an emulsion as long as it does not inhibit the effects of the present invention.

The binder resin (B) used in the present embodiment is said to improve ejection stability by suppressing deposition and adhesion at the nozzle of the inkjet head, and furthermore to increase blocking resistance and adhesive strength after lamination. From a viewpoint, the weight average molecular weight (Mw) is preferably 5,000 to 45,000, more preferably 10,000 to 30,000. When it is 5,000 or more, blocking resistance and adhesive strength after lamination can be sufficiently secured, and when it is 45,000 or less, the ejection stability from the inkjet head can be maintained in a suitable state, which is preferable. Furthermore, the binder resin (B) having the weight average molecular weight described above causes molecular motion of the binder resin (B) in the printed layer during lamination or the like, and forms an interaction with the laminate adhesive. It is believed that the adhesion between the layers is even higher.

The weight average molecular weight (Mw) of the binder resin (B) in the present invention and the number average molecular weight (Mn) described below can be measured by conventional methods. In the present invention, a TSKgel column (manufactured by Tosoh Corporation) and a GPC (manufactured by Tosoh Corporation, HLC-8120GPC) equipped with an RI detector were used, and THF was used as a developing solvent. is.

The glass transition temperature (Tg) of the binder resin (B) used in the present invention is preferably 35 to 110°C, more preferably 50 to 100°C, from the viewpoint of adhesive strength after lamination. If it is 35° C. or higher, it is excellent in ejection stability, and if it is 110° C. or lower, it does not cause deterioration of drying properties and adhesion after lamination.

The glass transition temperature of the binder resin (B) of the present invention is a value determined using a DSC (differential scanning calorimeter). Specifically, about 2 mg of a sample obtained by drying the resin was weighed on an aluminum pan, set in a DSC measurement holder, and the endothermic peak temperature of the chart obtained at a temperature increase of 5 ° C./min was measured according to the present invention. is the glass transition temperature at

From the viewpoint of suitably expressing the above effect, the content of the binder resin (B) of the present invention in the water-based ink composition is in the range of 1% by mass or more and 20% by mass or less based on the total mass of the water-based ink in terms of non-volatile matter. It is preferably in the range of 3% by mass or more and 15% by mass or less.

<Pigment>
Both inorganic pigments and organic pigments can be used as the pigment of the water-based ink (A) used in this embodiment. These pigments may be used alone or in combination of two or more. Examples of inorganic pigments include white pigments such as titanium oxide, zinc white, zinc sulfide, calcium carbonate, precipitated barium sulfate, and alumina white, and black pigments such as carbon black and iron oxide.

Titanium oxide is preferably used as the white pigment. Both the anatase type and the rutile type can be used as titanium oxide, but it is preferable to use the rutile type in order to increase the hiding power of printed matter. Moreover, although it may be produced by any method such as the chlorine method or the sulfuric acid method, it is preferable to use titanium oxide produced by the chlorine method because of its high degree of whiteness.

Titanium oxide is more preferably a pigment whose surface has been treated with an inorganic compound and/or an organic compound. Examples of inorganic compounds include compounds of silicon (Si), aluminum, zirconium, tin, antimony, titanium, and hydrated oxides thereof. Examples of organic compounds include polyhydric alcohols, alkanolamines or derivatives thereof, higher fatty acids or metal salts thereof, and organometallic compounds. It is more preferably used because it can be hydrophobized to improve dispersion stability.

It is also preferable to use hollow resin particles as the white pigment. Hollow resin particles have a smaller specific gravity (apparent density) than titanium oxide or the like, and can easily suppress sedimentation over time, so that ink with excellent storage stability can be obtained. Further, in order to obtain a white ink having both storage stability and hiding property, hollow resin particles and titanium oxide may be used together as a pigment.

Carbon black (C.I. Pigment Black 7) produced by the furnace method or the channel method is preferably used as the black pigment. For example, these carbon blacks have characteristics such as a primary particle diameter of 11 to 40 nm, a specific surface area of 50 to 400 m2/g by the BET method, a volatile content of 0.5 to 10% by mass, and a pH value of 2 to 10. is preferred. Specific examples of commercially available products having such characteristics include No. 33, 40, 45, 52, 900, 2200B, 2300, MA7, MA8, MCF88 (manufactured by Mitsubishi Chemical); RAVEN1080, 1255 (manufactured by Birla Carbon); ELFTEX415 (manufactured by Cabot Corporation); Nipex 90, 150T, 160IQ, 170IQ, 75, PrintX85, 95, 90, 35 (manufactured by Orion Engineered Carbons), etc., any of which can be preferably used.

In addition to carbon black, black pigments such as aniline black, lumogen black, azomethine azo black, and the like can be used. Also, a plurality of chromatic pigments such as cyan pigments, magenta pigments, yellow pigments, brown pigments, and orange pigments, which will be described later, can be used to form a black pigment.

Examples of organic pigments include azo pigments, phthalocyanine pigments, anthraquinone pigments, quinacridone pigments, isoindolinone pigments, quinophthalone pigments, dye lake pigments, and fluorescent pigments.

Specific examples of color indexes include C.I. I. Pigment Blue 1, 2, 3, 15:1, 15:3, 15:4, 15:6, 16, 22, 60, 64 and the like.

As a magenta pigment, C.I. I. Pigment Red 5, 7, 12, 31, 48, 49, 52, 53, 57, 112, 120, 122, 146, 147, 149, 150, 168, 170, 184, 185, 188, 202, 209, 238, 242, 254, 255, 264, 269, 282; I. Pigment Violet 19, 23, 29, 30, 37, 40, 50 and the like.

As a yellow pigment, C.I. I. Pigment Yellow 10, 11, 12, 13, 14, 16, 17, 20, 24, 74, 83, 86, 93, 94, 95, 109, 110, 117, 120, 125, 128, 137, 138, 139, 147, 148, 150, 151, 154, 155, 166, 168, 180, 185, 213 and the like.

In addition to the above, special colors such as orange pigments, green pigments, and brown pigments can also be used. Specifically, C.I. I. Pigment Orange 16, 36, 38, 40, 43, 62, 63, 64, 71, C.I. I. Pigment Green 7, 10, 36, Pigment Brown 23, 25, 26 and the like.

In addition, in the water-based ink (A) used for producing the laminate of the present embodiment, a plurality of the above pigments can be mixed and used in order to keep the hue and coloring property of the printed matter within a suitable range. For example, a small amount of one or more pigments selected from cyan pigments, magenta pigments, orange pigments, and brown pigments can be added to black ink using carbon black in order to improve the color tone at low printing rates. .

These pigments are preferably contained in the range of 2% by mass to 20% by mass, and in the range of 2.5% by mass to 15% by mass, with respect to the total amount of ink, except in the case of white ink. is more preferable, and it is particularly preferable to be contained in the range of 3% by mass or more and 10% by mass or less. In the case of white ink, the pigment content is preferably 5% by mass or more and 40% by mass or less, more preferably 8% by mass or more and 30% by mass or less, relative to the total amount of white ink. By setting the pigment content to 2% by mass or more (5% by mass or more in the case of white ink), it is possible to obtain sufficient color development (or concealability in the case of white ink) even in 1-pass printing. . In addition, by setting the pigment content to 20% by mass or less (40% by mass or less in the case of white ink), the viscosity of the ink can be kept within a range suitable for inkjet printing, and the storage stability of the ink can be improved. It can be maintained in good condition, and as a result, long-term ejection stability can be ensured.

<Pigment dispersion resin>
Methods for stably dispersing and holding a pigment in an aqueous ink include (1) a method of coating at least a portion of the surface of the pigment with a water-soluble or water-insoluble pigment dispersing resin; A method of adsorbing and dispersing a water-dispersible surfactant on the pigment surface, (3) chemically and physically introducing a hydrophilic functional group onto the pigment surface, and dispersing it in the ink without a dispersing resin or surfactant. method (self-dispersing pigment), and the like.

For the water-based ink (A) used in the production of the laminate of the present embodiment, the supplementary method of (1) above, that is, the method using a pigment dispersing resin, is preferably selected. This is because by selecting and examining the composition and molecular weight of the polymerizable monomers constituting the resin, it is possible to easily adjust the ability of the pigment dispersing resin to cover the pigment and the charge of the pigment dispersing resin. This is because it is possible to impart dispersion stability even with the addition of a soluble solvent, and furthermore, a printed matter having excellent ejection stability, color development, and color reproducibility can be obtained.

The type of the pigment dispersion resin is not particularly limited. , urethane-based and ester-based resins. Among them, one or more resins selected from α-olefin (anhydride) maleic acid, (meth)acrylic, and styrene (meth)acrylic from the viewpoint of strengthening the adsorption of the pigment and stabilizing the pigment dispersion. is preferably used. In this specification, "(anhydride) maleic acid" represents maleic acid or maleic anhydride.

Moreover, the pigment dispersion resin preferably contains a structural unit derived from a monomer having an aromatic ring structure. This is because the aromatic ring structure contained in the pigment dispersion resin and the nitrogen atom in the urethane bond contained in the laminate adhesive composition (J) form π-cationic interaction to improve adhesive strength. The effect of ensuring and improving the dispersion stability of the pigment in the ink (A) is favorable. The amount of structural units derived from a monomer containing an aromatic ring structure is preferably 10 to 80% by mass, more preferably 15 to 75% by mass, based on the total amount of the pigment dispersion resin, and 20 to 70% by mass is particularly preferred.

Moreover, the weight average molecular weight of the pigment dispersion resin is preferably 5,000 or more and 100,000 or less. It is more preferably in the range of 10,000 or more and 50,000 or less, and still more preferably in the range of 15,000 or more and 30,000 or less. When the weight-average molecular weight is within the above range, the pigment is stably dispersed in water, and the viscosity can be easily adjusted when applied to the water-based ink (A). In particular, when the weight average molecular weight is 5,000 or more, the pigment dispersing resin is difficult to dissolve in the water-soluble organic solvent added to the water-based ink (A). Strong resin adsorption and excellent dispersion stability. Further, when the weight-average molecular weight is 100,000 or less, the viscosity at the time of dispersion can be kept low, and the ejection stability from the inkjet head is excellent, which enables stable printing over a long period of time.

When a water-soluble resin is used as the pigment dispersing resin, its acid value is preferably 60-400 mgKOH/g. By setting the acid value within the above range, the dispersion stability of the pigment and the storage stability of the ink can be made suitable. Further, the acid value is more preferably 120 to 350 mgKOH/g, still more preferably 150 to 300 mgKOH/g. On the other hand, when a water-insoluble resin is used as the pigment dispersion resin, its acid value is preferably 0 to 100 mgKOH/g, more preferably 5 to 90 mgKOH/g, and more preferably 10 to 80 mgKOH/g. More preferred. The acid value of the pigment dispersion resin can be measured in the same manner as the binder resin.

In this embodiment, the blending amount of the pigment dispersing resin is preferably 1 to 50% by mass based on the pigment. By setting the amount of the pigment dispersing resin to 1 to 50% by mass based on the pigment, the viscosity of the pigment dispersion is suppressed, and the viscosity stability and dispersion stability of the pigment dispersion and water-based ink (A) are improved. can be made into something The blending amount of the pigment dispersing resin with respect to the pigment is more preferably 2 to 45% by mass, still more preferably 4 to 35% by mass.

<Water-soluble organic solvent>
The water-based ink (A) used in the production of the laminate of the present embodiment improves ejection stability by suppressing ink sticking on the nozzles of the inkjet head, and furthermore, dries on a non-permeable substrate. From the viewpoint of improving the properties, it is preferable to use a water-soluble organic solvent. Moreover, the dispersion stability of the water-based ink (A) can be made suitable, and as a result, an ink having excellent ejection properties and storage stability can be obtained.

The water-soluble organic solvent is not particularly limited, and any known solvent can be used. From the viewpoint of compatibility and affinity, it is preferable to contain a glycol ether solvent and/or an alkyl polyol solvent. In particular, it is preferable that one or more hydroxyl groups are included in the molecular structure. This is because the hydroxyl group of the water-soluble organic solvent reacts with the isocyanate component (K) of the lamination adhesive composition (J) to improve the adhesive strength after lamination. Furthermore, the boiling point of the water-soluble organic solvent under 1 atmosphere is preferably 100°C or higher and lower than 240°C. When the temperature is 100°C or higher, the jetting property, dispersion stability, and moisture retention of the water-based ink (A) are improved. The blocking resistance of the laminate and the adhesive strength of the laminate are improved.

The boiling point under 1 atmosphere can be measured by using a thermal analysis device such as DSC (differential scanning calorimetry).

The total amount of the water-soluble organic solvent (E) in the water-based ink (A) used for producing the laminate of the present embodiment is 3% by mass or more and 40% by mass or less with respect to the total amount of the water-based ink (A). preferable. Furthermore, from the viewpoint of ensuring ejection stability from an inkjet head and sufficient adhesive strength when combined with the laminate adhesive composition (J), it is more preferably 5% by mass or more and 35% by mass. It is particularly preferable to be 8% by mass or more and 30% by mass or less. By setting the total amount of the water-soluble organic solvent to 3% by mass or more, the ink has excellent moisture retention properties and ejection stability, and the adhesive strength after lamination is improved. Further, by setting the total content of the water-soluble organic solvent to 40% by mass or less, it is possible to obtain a printed material having good drying property and color bleeding, and good anti-blocking property.

Suitable alkyl polyol solvents include 1,2-ethanediol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4 -butanediol, 1,2-pentanediol, 1,5-pentanediol, 1,2-hexanediol, 2,2-dimethyl-1,3-propanediol, 2-methyl-1,3-propanediol, 2 -ethyl-2-methyl-1,3-propanediol, 3-methyl-1,3-butanediol, 3-methyl-1,5-pentanediol, 2-methyl-2-propyl-1,3-propanediol , 2-methylpentane-2,4-diol, 2-ethyl-1,3-hexanediol, diethylene glycol, dipropylene glycol and the like.

Suitable glycol ether solvents include, for example, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monopropyl ether, diethylene glycol monobutyl ether, triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, triethylene glycol monobutyl ether, tetra Glycol monomethyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monopropyl ether, dipropylene glycol monobutyl ether, tripropylene glycol monomethyl ether, etc. Alkyl ethers; glycol dialkyl ethers such as diethylene glycol diethyl ether, diethylene glycol isopropyl methyl ether, diethylene glycol butyl methyl ether, triethylene glycol dimethyl ether, triethylene glycol butyl methyl ether, tetraethylene glycol dimethyl ether, and the like.

Among them, 1,2-propanediol, 1,2-butanediol, and 1,3-butanediol can achieve both excellent ejection stability, moisturizing properties, and drying properties, as well as adhesion after lamination. , 1,2-pentanediol, 1,5-pentanediol, 1,2-hexanediol, diethylene glycol monopropyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, dipropylene glycol monopropyl ether, and dipropylene It is preferable to select one or more selected from the group consisting of glycol monobutyl ether.

<Surfactant>
The water-based ink (A) of the present embodiment preferably contains a surfactant for the purpose of adjusting its surface tension, ensuring wettability on the transparent substrate 1, and improving print image quality. On the other hand, if the surface tension is too low, the nozzle surface of the inkjet head will be wetted with the water-based ink (A), impairing ejection stability. From the viewpoint of ensuring optimum wettability and realizing stable ejection from the inkjet head, it is preferable to use a surfactant such as a siloxane-based, acetylene-based, acrylic, fluorine-based, or polyoxyalkylene alkyl ether-based surfactant. It is particularly preferred to use siloxane-based and/or acetylenic surfactants. The amount of the surfactant to be added is preferably 0.05% by mass or more and 5.0% by mass or less, more preferably 0.1% by mass or more and 3.0% by mass or less, relative to the total amount of the water-based ink (A). By making it 0.05% by mass or more, the function of the surfactant can be sufficiently exhibited, and by making it 5.0% by mass or less, the storage stability and ejection stability of the water-based ink (A) are improved. can be maintained at a suitable level.

<Other ingredients>
Further, the water-based ink (A) used for producing the laminate of the present embodiment contains, in addition to the above components, if necessary, a pH adjuster, an antifoaming agent, an antiseptic, an infrared absorber, an ultraviolet absorber, Additives such as thickeners can be added as appropriate. An example of the amount of these additives to be added is preferably 0.01% by mass or more and 10% by mass or less with respect to the total mass of the water-based ink (A).

<Adhesive Layer (III), Laminate Adhesive Composition (J)>
Next, the adhesive layer (III) constituting the laminate of this embodiment will be described. The adhesive layer (III) is a layer made of a cured film of a laminate adhesive composition (J) containing an isocyanate component (K) and a polyol component (M), and the isocyanate group of the isocyanate component (K) to the number of moles of hydroxyl groups in the polyol component (M) is in the range of 1.0 to 3.0, and the number average molecular weight of the polyol component (M) is 500 ~3,200, including polyester polyols or polyether polyols.

<Isocyanate component (K)>
As the isocyanate component (K), the isocyanate compound may be used as it is, or an adduct, isocyanurate, or the like obtained from the isocyanate compound may be used. The "adduct" is an adduct of an isocyanate compound and trimethylolpropane, and the "isocyanurate" is a trimer of the isocyanate compound. Further, when used in the laminate of the present embodiment, an isocyanate compound is a reaction product of a polyol (different from the polyol component (M) described later) and contains a urethane prepolymer having an isocyanate group at the end. It is preferably in the form of a compound. By including the urethane prepolymer, it becomes possible to adjust the molecular weight of the isocyanate component, thereby obtaining a strong and flexible film and improving the adhesive strength as a laminate. Furthermore, the polyol is preferably a polyether polyol or a polyester polyol, particularly preferably a polyether polyol. This improves the compatibility with the polyol component (M), which will be described later, and increases the cohesive strength of the adhesive layer (III). Moreover, the coating properties of the lamination adhesive composition (J) during lamination are improved, and high adhesive strength as a laminate can be obtained. A specific example of a preferable urethane prepolymer is a urethane prepolymer compound obtained by reacting an aromatic isocyanate and a polyether polyol, which will be described later.

The isocyanate compound is not particularly limited, and any known one can be used, but from the viewpoint of increasing the adhesive strength after lamination, it is preferable to include an aromatic isocyanate compound. The reactivity of the aromatic isocyanate compound is higher than that of the aliphatic or alicyclic isocyanate compound, and as a result, the laminate adhesive composition (J) exhibits good adhesive strength and strong adhesion. It becomes the agent layer (III). In addition, the π electrons of the aromatic ring structure of the aromatic isocyanate compound are thought to form an intermolecular interaction with the ink layer (II), thereby improving the adhesive strength of the laminate as a whole.

The proportion of the aromatic isocyanate compound contained in the isocyanate component (K) is preferably 10% by mass or more and 70% by mass or less. When the amount of the aromatic isocyanate compound is within the above range, the coating appearance of the ink layer in the laminate is improved, and the adhesive strength after lamination is also increased. More preferably, it is 20% by mass or more and 60% by mass or less.

A compound having a plurality of isocyanate groups is preferably used as the aromatic isocyanate compound. Specific examples of the aromatic isocyanate compounds include m-phenylene diisocyanate, p-phenylene diisocyanate, 4,4′-diphenylmethane diisocyanate, 2,4′-diphenylmethane diisocyanate, 2,2′-diphenylmethane diisocyanate, 2,4- tolylene diisocyanate, 2,6-tolylene diisocyanate, dialkyldiphenylmethane diisocyanate, tetraalkyldiphenylmethane diisocyanate, 3,3'-dimethyl-4,4'-biphenylene diisocyanate, 3,3'-dimethoxy-4,4'-biphenylene diisocyanate , naphthylene-1,5-diisocyanate, tetrahydronaphthylene-1,5-diisocyanate, 4,4′-dibenzylisocyanate, xylylene diisocyanate, tetramethylxylylene diisocyanate and the like.

Specific examples of isocyanate compounds other than the aromatic isocyanate compounds include aliphatic diisocyanates such as hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, and lysine diisocyanate; dicyclohexylmethane diisocyanate, isophorone diisocyanate, 1,4-cyclohexane diisocyanate, and water. Examples include alicyclic diisocyanates such as xylene diisocyanate and hydrogenated tolylene diisocyanate.

Examples of the polyether polyol include compounds obtained by polymerizing oxirane compounds such as ethylene oxide, propylene oxide, butylene oxide and tetrahydrofuran using water, ethylene glycol, propylene glycol, trimethylolpropane, glycerin and the like as initiators. is mentioned. Also, a plurality of oxirane compounds having different numbers of functional groups can be used in combination.

On the other hand, examples of the polyester polyol include compounds obtained by reacting a polyvalent carboxylic acid component and a glycol component. Examples of polyvalent carboxylic acid components include polyvalent carboxylic acids such as terephthalic acid, isophthalic acid, adipic acid and sebacic acid, dialkyl esters thereof, and mixtures thereof. Examples of glycol components include ethylene glycol, propylene glycol, diethylene glycol, butylene glycol, neopentyl glycol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, polyoxyethylene glycol and polyoxypropylene glycol. , polytetramethylene ether glycol, or mixtures thereof.

When used in the laminate of the present embodiment, the isocyanate group content in the entire isocyanate component (K) is preferably 10% by mass or more and less than 20% by mass. When the isocyanate group content in the isocyanate component (K) is within the above range, it is possible to form a laminate having a better appearance without impairing the print image quality. The isocyanate group content (% by mass) is determined by titration with hydrochloric acid.

<Polyol component (M)>
Next, the polyol component (M) contained in the laminate adhesive composition (J) will be explained.

The polyol component (M) of the present embodiment has a number average molecular weight of 500 to 3,200 and includes polyester polyol or polyether polyol (both of which have terminal hydroxyl groups). Polyester polyols and polyether polyols have excellent organic solvent resistance due to their structures, have high affinity with the binder resin (B) of the water-based ink (A), and are used in the ink layer of the laminate adhesive composition (J) ( It has excellent coating suitability for II), and it is possible to form a uniform coating film without unevenness. As a result, the printed image is not damaged, the appearance is good, and the adhesive strength as a laminate can be increased. Furthermore, since a flexible coating film is formed, a high cohesive force can be obtained between the ink layer (II) and the adhesive layer (III).

Further, when the number average molecular weight is large, the reaction of the isocyanate component (K) with the NCO group is slow, and the isocyanate component (K) excessively permeates the ink layer (II), resulting in adhesion of the adhesive layer (III). power is reduced. If the number average molecular weight is small, the reaction between the polyol component (M) and the NCO groups of the isocyanate component (K) will proceed aggressively, resulting in the ethylenic heterogeneous content contained in the binder resin (B) of the water-based ink (A). The reaction with the hydroxyl group derived from the saturated monomer (b2) is poor, making it difficult to obtain a cohesive force between the ink layer (II) and the adhesive layer (III). By setting the number average molecular weight of the polyol component (M) to a specific range, the reaction with the NCO group of the isocyanate component (K) is not biased, and the laminate adhesive composition ( J) has a high cross-linking density, resulting in a cured film that is both strong and flexible, and provides a cohesive force between the ink layer (II) and the adhesive layer (III), resulting in a strong adhesive strength as a laminate. can get.

In a more preferred embodiment of the polyol component (M), the polyol having a molecular weight of 500 to 3,200 accounts for 25% by mass or more, preferably 55% by mass or more of the total polyol component (M). For example, by using GPC, after calibration with a standard sample, the molecular weight distribution is measured to determine the amount of the polyol component (M) having a molecular weight of 500 to 3,200. The total amount of polyester polyol and polyether polyol contained in polyol (M) is preferably 40% by mass or more, more preferably 55% by mass or more.
The structural properties of the polyester polyol or polyether polyol described above, and the effect of keeping the number average molecular weight within the specific range, can be obtained more effectively, and a laminate with high adhesive strength can be obtained.

Examples of the polyester polyol (having a terminal hydroxyl group) include polyvalent carboxylic acids such as terephthalic acid, isophthalic acid, adipic acid, azelaic acid, and sebacic acid, dialkyl esters thereof, or mixtures thereof, and ethylene glycol. , propylene glycol, diethylene glycol, butylene glycol, neopentyl glycol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, polyoxyethylene glycol, polyoxypropylene glycol, polytetramethylene ether glycol, etc. or a reaction product with a mixture thereof; or a ring-opening polymerization reaction product of lactones such as polycaprolactone, polyvalerolactone, poly(β-methyl-γ-valerolactone); As the polyester polyol, a vegetable oil such as castor oil and a polyester compound having a hydroxyl group derived from the vegetable oil can also be used.

Furthermore, it is also possible to use those obtained by reacting some of the hydroxyl groups in the polyester polyols exemplified above with an acid anhydride such as trimellitic anhydride. By using a polyester polyol to which an acid anhydride is added, the adhesion to the film substrate and the adhesive strength of the laminate as a whole can be improved. When adding trimellitic anhydride, the amount used is preferably 0.1 to 5% by mass based on 100% by mass of the polyester polyol before the reaction.

Examples of the polyether polyol (having a terminal hydroxyl group) include oxirane compounds such as ethylene oxide, propylene oxide, butylene oxide, and tetrahydrofuran, water, ethylene glycol, propylene glycol, trimethylolpropane, glycerin, and the like. A compound obtained by polymerization using a low-molecular-weight polyol as an initiator may be mentioned.

The polyether ester polyol is obtained by reacting dibasic acids such as terephthalic acid, isophthalic acid, adipic acid, azelaic acid and sebacic acid, dialkyl esters thereof, or mixtures thereof with polyether diol. compounds that are

The polyol component (M) of the present embodiment may contain other polyols in addition to polyester polyols or polyether polyols (both of which have terminal hydroxyl groups), as long as the object of the present invention is not impaired. can.

Other polyols include polymer polyols such as polycarbonate polyols, polyurethane polyols, polyesteramide polyols, and acrylic polyols (all of which have terminal hydroxyl groups), ethylene glycol, propylene glycol, diethylene glycol, butylene glycol, neopentyl glycol, Low-molecular-weight diols such as 1,6-hexanediol and 3-methyl-1,5-pentanediol, and low-molecular-weight triols such as trimethylolpropane and glycerin can be used.

As the polyol component (M), one of the polyols exemplified above may be used alone, or two or more of them may be used in combination. In particular, in the case of the laminate adhesive composition (J) used for forming the laminate of the present embodiment, it is preferable that two or more polyols having different number average molecular weights are included as the polyol component (M). Specifically, a polyol having a number average molecular weight of 100 or more and less than 500, a polyol having a number average molecular weight of 500 or more and less than 2,000, and a polyol having a number average molecular weight of 2,000 or more and 5,000 or less or a case of containing a polyol having a number average molecular weight of 100 or more and less than 1,000 and a polyol having a number average molecular weight of 1,000 or more and 5,000 or less. Among the above, polyols having a number average molecular weight of less than 1,000 have excellent permeability to the ink layer (II) and also have good reactivity with the isocyanate component (K). and the adhesion to the transparent substrate 1. In addition, the polyol having a number average molecular weight of 1,000 or more is effective in increasing the cohesive force of the cured film of the laminate adhesive composition (J), and as a result contributes to the strength improvement of the adhesive layer (III). do.

In the laminate adhesive composition (J) of the present embodiment, NCO/OH, which is the ratio of the number of moles of isocyanate groups in the isocyanate component (K) to the number of moles of hydroxyl groups in the polyol component (M) used in combination The ratio ranges from 1.0 to 3.0. It is more preferably in the range of 1.2 to 2.6, still more preferably in the range of 1.4 to 2.2. By setting the ratio of the number of moles of isocyanate groups in the isocyanate component (K) to the number of moles of hydroxyl groups in the polyol component (M) used in combination (NCO/OH ratio) to 1.0 or more, the polyol component (M ) can provide sufficient NCO groups to react with the hydroxyl groups of ), and an effective film of the laminate adhesive composition with high adhesion can be obtained. In addition, it is possible to obtain a laminate that maintains good adhesive strength after lamination. For example, even if aging treatment is performed in a high-humidity environment after lamination, the adhesive strength does not decrease. By setting the NCO/OH ratio to 3.0 or less, the isocyanate component having unreacted NCO groups can be reduced, and poor curing of the laminate adhesive composition can be suppressed.

<Other ingredients>
The laminate adhesive composition (J) used for forming the laminate of the present embodiment further contains a particle component having an average particle size of 1×10 ⁻⁴ mm or more and 4×10 ⁻⁴ mm or less. can be done. When the laminate adhesive composition (J) containing a particle component having an average particle diameter within the above range is used, the gas barrier property of the transparent substrate 1 is high, and even when coating and bonding are performed at high speed, Even if there is, it is possible to obtain a laminate having a more excellent appearance and adhesive strength. The "average particle size" is the cumulative 50% size on a volume basis, and can be obtained, for example, using Nanotrac UPA-EX150 manufactured by Nikkiso Co., Ltd.

Either an inorganic compound or an organic compound can be used as such a particle component, and may be used alone or in combination of two or more.

Examples of particle components made of inorganic compounds include aluminum oxide, aluminum silicate, alumina white, zinc oxide, magnesium silicate, magnesium carbonate, magnesium hydroxide, calcium carbonate, calcium hydroxide, calcium oxide, calcium silicate, and sulfuric acid. Powders of calcium, titanium oxide, silica, zeolite, activated carbon, kaolin, talc, mica, graphite, montmorillonite, sericite, bentonite, pearlite, zeolite, fluorite, and the like are included. Among these, silica and talc are preferred.

As the particle component composed of an organic compound, resin fine particles that can be used in the water-based ink (A) described above can be suitably used. Resin fine particles such as polyimide resin, polyamide resin, polyacetal resin, nylon 6, nylon 12, and cellulose may also be used. Among the above, benzoguanamine-based resin fine particles can be preferably used.

The amount of the particle component added is preferably 0.01 to 10% by mass with respect to the total amount of the laminate adhesive composition (J). By setting it as the said range, both an external appearance and adhesive strength can be improved.

A silane coupling agent may be added to the laminate adhesive composition (J) used for forming the laminate of the present embodiment. As the silane coupling agent, those having a functional group such as a vinyl group, an epoxy group, an amino group, an imino group and a mercapto group, and a functional group such as a methoxy group and an ethoxy group can be preferably used. For example, chlorosilanes such as vinyltrichlorosilane, aminosilanes such as N-(dimethoxymethylsilylpropyl)ethylenediamine, N-(triethoxysilylpropyl)ethylenediamine, epoxysilanes such as γ-glycidoxypropyltrimethoxysilane, and vinyltriethoxysilane. and vinyl silanes such as The amount of the silane coupling agent to be added is preferably 0.1 to 5% by mass with respect to the total amount of the laminate adhesive composition (J).

In addition, the laminate adhesive composition (J) used for forming the laminate of the present embodiment further contains an antioxidant, an ultraviolet absorber, a hydrolysis inhibitor, an antifungal agent, a thickener, and a plasticizer. , antifoaming agents, pigments, fillers and the like may be used as necessary. Further, in order to further improve the adhesion performance, auxiliary agents such as titanate-based coupling agents, phosphoric acid, phosphoric acid derivatives, acid anhydrides and adhesive resins can be used. In addition, known catalysts, additives, etc. can be used to control the curing reaction.

The adhesive layer (III) constituting the laminate of the present embodiment is obtained by mixing a composition containing at least an isocyanate component (K) and a composition containing at least a polyol component (M) before use, and lamination adhesion. It is preferably formed after the precursor of the adhesive layer is obtained by coating the ink layer (II) and/or the substrate 4 after preparing the adhesive composition (J). Moreover, when the laminate adhesive composition (J) contains the above-described particle component, it is preferable that the particle component is preliminarily mixed with at least the composition containing the polyol component (M).

Further, the composition containing at least the isocyanate component (K) and the composition containing at least the polyol component (M) are preferably mixed at a temperature as low as possible within a range in which fluidity can be ensured. It is preferable to carry out at 25° C. or higher and 80° C. or lower. Furthermore, the viscosity at 60° C. immediately after the lamination adhesive composition (J) is prepared is preferably 50 mPa·s or more and 5000 mPa·s or less, more preferably 50 mPa·s or more and 3000 mPa·s or less. In the present invention, "immediately after preparation" means within 1 minute after uniform mixing, and the above viscosity is a value measured with a Brookfield viscometer. If the viscosity at 60° C. is 5,000 mPa·s or less, the ink layer (II) and/or the substrate 4 can be easily coated, and good workability can be ensured. , the paint appearance is also improved. Further, if the viscosity at 60° C. is 50 mPa·s or more, the initial cohesive force is sufficiently high, so that the adhesive strength of the entire laminate is improved, and furthermore, the thickness becomes uniform during coating, resulting in poor appearance. No warpage occurs.

Next, the laminate of this embodiment and the method for producing the laminate will be described. As described above, the laminate of the present invention has the transparent substrate 1, the ink layer (II), the adhesive layer (III), and the substrate 4 in this order.

<Transparent substrate 1>
As used herein, the term “transparent substrate” means that the substrate transmits visible light. Specifically, black characters (8-point MS Mincho letters ) is visible. Polyolefin resins such as polyethylene and polypropylene; polyester resins such as polyethylene terephthalate (hereinafter also referred to as PET), polycarbonate and polylactic acid; polystyrene, AS resin, and ABS as the transparent substrate 1 constituting the laminate of this embodiment. Polystyrene resins such as resins; polyamide resins such as nylon 6 and nylon 12; chlorine-containing resins such as polyvinyl chloride and polyvinylidene chloride; cellophane; Available. The substrate used for these transparent substrates 1 may be coated with polyvinyl alcohol or the like, or may be subjected to surface treatment such as corona treatment or plasma treatment.

<Ink layer (II)>
The ink layer (II) constituting the laminate of the present embodiment is a layer made of a dried film of a water-based inkjet ink (A) containing a binder resin (B) and a pigment, and the hydroxyl groups of the binder resin (B) a water-based resin having a value of 3 mgKOH/g or more and containing, as structural units, an ethylenically unsaturated monomer (b1) containing an acid group and an ethylenically unsaturated monomer (b2) containing a hydroxyl group. contains.

The thickness of the ink layer (II) constituting the laminate of this embodiment is preferably 0.2 to 20 μm. By setting the coating amount within the above range, it is possible to obtain good print quality with suppressed color mixture bleeding, and to obtain high adhesive strength as a laminate. In addition, the water-based ink (A) dries well, prevents blocking when printing is overlaid, and does not interfere with post-processing such as lamination. The thickness of the ink layer (II) is the thickness of the film after drying the water-based ink (A). It is preferably 0.4 to 10 μm.

The water-based ink (A) may be used in a single color, or may be used as a set of a plurality of water-based inks (A) in which a plurality of colors are combined according to the application. Although the combination is not particularly limited, a full-color image can be obtained by using, for example, three colors of cyan, yellow, and magenta. In addition, by adding black ink, the feeling of blackness can be improved, and the visibility of characters and the like can be improved. Furthermore, color reproducibility can be improved by adding colors such as orange, green, and violet. In addition, by printing with white ink, a clear image can be obtained and, as a laminate for flexible packaging materials, the concealability of contents can be improved. Furthermore, an ink set containing ink (clear ink) that does not substantially contain a colorant component, excluding the pigment from the water-based ink (A) of the present invention, is used as a component, and an ink layer containing no pigment exists. may

The water-based ink (A) is printed on the transparent substrate 1 by an inkjet printing method. At that time, it is preferable to print by a one-pass printing inkjet printing method (hereinafter also referred to as “one-pass printing method”). The “one-pass printing method” is a printing method in which an inkjet head is scanned only once against a stationary substrate, or a substrate is passed through the bottom of a fixed inkjet head only once. The same ink is not printed again on the water-based ink (A) printed thereon. Compared to inkjet printing (multi-pass printing method), in which the inkjet head is scanned multiple times, the one-pass printing method requires fewer scans and can increase the printing speed, so it is suitable for industrial applications that require high printing speed. be. In addition, it is also suitable because printed matter with high print quality can be obtained at a high recording resolution of 600 dpi or more. The "recording resolution" is expressed in units of dpi (Dots Per Inch) and represents the number of water-based inkjet ink droplets printed per inch. In addition, the term "recording resolution" as used herein refers to both the recording resolution in the transport direction of the substrate and the recording resolution in the direction perpendicular to the transport direction within the surface of the substrate (hereinafter referred to as the recording width direction). shall be

When printing the water-based ink (A) by a one-pass printing method, the drop volume of the water-based ink (A) largely depends on the performance of the inkjet head. It is preferably in the range of 0.6 to 60 pL in order to obtain a printed matter excellent in adhesion strength. More preferably 1 to 50 pL, particularly preferably 1.4 to 40 pL. Also, in order to obtain high-quality images, it is particularly preferable to use a gradation specification ink jet head capable of changing the drop volume.

In the method for producing a laminate of the present embodiment, after printing the water-based ink (A) on the transparent substrate 1, the water-based ink (A) is applied in order to dry and/or cure the water-based ink (A). It may be heated, and the heating method used at that time is not particularly limited. Examples thereof include a heat drying method, a hot air drying method, an infrared drying method (for example, an infrared ray with a wavelength of 700 to 2500 nm), a microwave drying method, and a drum drying method. Moreover, the above drying methods may be used alone or in combination. At that time, in order to prevent color mixture blurring and color unevenness, the heating is preferably applied within 20 seconds, more preferably within 10 seconds, after printing the water-based ink (A).

The water-based ink (A) of the present invention can also be used in the form of an ink-pretreatment liquid set in combination with a pretreatment liquid containing a flocculant. A pretreatment liquid containing a flocculating agent can form a layer (ink flocculating layer) on a recording medium in which solid components contained in the ink are intentionally flocculated. By allowing the water-based ink (A) of the present invention to land on the ink coagulation layer, it is possible to prevent bleeding between ink droplets and color unevenness, thereby significantly improving print image quality. Furthermore, depending on the material used for the pretreatment liquid, the adhesion, anti-blocking property, and suitability for lamination of the printed matter can also be improved.

The "flocculant" in the present invention is a component contained in the water-based ink, capable of destroying the dispersed state of the pigment and causing it to coagulate, and/or insolubilizing the binder resin (B) and increasing the viscosity of the water-based ink. means. The coagulant used in the pretreatment liquid combined with the water-based ink of the present invention preferably contains one or more selected from metal salts and cationic polymer compounds from the viewpoint of improving print image quality. Among them, it is preferable to use a metal salt, and it is particularly preferable to include a salt of one or more polyvalent metal ions selected from the group consisting of Ca ²⁺ , Mg ²⁺ , Zn ²⁺ and Al ³⁺ . When a metal salt is used as a flocculating agent, its content is preferably 2 to 25% by mass, particularly preferably 3 to 20% by mass, based on the total amount of the pretreatment liquid.

In addition, a water-soluble organic solvent, a surfactant, a pH adjuster, an antifoaming agent, a thickener, an antiseptic, and the like can be appropriately added to the pretreatment liquid.

<Adhesive layer (III)>
The adhesive layer (III) constituting the laminate of the present embodiment is a layer made of a cured film of a laminate adhesive composition (J) containing a polyol component (M) and an isocyanate component (K), and the isocyanate The NCO/OH ratio, which is the ratio of the number of moles of isocyanate groups in the component (K) to the number of moles of hydroxyl groups in the polyol component (M), is in the range of 1.0 to 3.0, and the polyol component (M) has a number average molecular weight of 500 to 3,200, and includes polyester polyols or polyether polyols. The laminate adhesive composition (J) is laminated on the ink layer (II) and/or on the substrate 4 to prepare an adhesive layer precursor, and then the adhesive layer precursor is The laminate of the present embodiment is obtained by superimposing the ink layer (II) and the base material 4 through each other, and further curing the precursor of the adhesive layer to form the adhesive layer (III).

As a method of laminating the ink layer (II) and the substrate 4 via the precursor of the adhesive layer to produce a laminate, there is lamination.
As a lamination method, known lamination methods such as dry lamination, non-solvent lamination, extrusion lamination, and hot-melt lamination can be used. Dry lamination and non-solvent lamination, in which the laminating adhesive composition (J) is applied in a roller form, are preferred because they allow the laminating adhesive composition (J) to be evenly and uniformly coated and the amount of lamination can be easily controlled. That is, in the dry lamination method, a volatile organic solvent such as ethyl acetate is used to dilute the lamination adhesive composition (J), and the lamination adhesive composition (J) is applied using a gravure roll coater, a reverse roll coater, or the like. Apply to the surface of the object. After that, the organic solvent is volatilized by drying to prepare a precursor of the adhesive layer, and the ink layer (II) and the base material 4 are laminated. In the non-solvent lamination method, a roller such as a roll coater heated to about 25 to 120 ° C. is used to laminate the laminate adhesive composition (J) on the surface of the object, to prepare an adhesive layer precursor, and the ink Layer (II) and substrate 4 are superimposed.

The lamination amount of the lamination adhesive composition (J) is appropriately selected according to the type of object, lamination conditions, etc., but is usually 1.0 g/m ² or more and 5.0 g/m ² or less, It is preferably 1.5 g/m ² or more and 4.5 g/m ² or less. By superimposing the ink layer (II) and the substrate 4 and allowing them to stand still (aging) for about one day, the laminate adhesive composition (J) is cured to form the laminate of the present embodiment. In addition, if the laminate adhesive composition (J) used in the laminate of the present embodiment, for example, even in a state of high environmental humidity during lamination and aging, the laminate having sufficient adhesive strength is obtained.

<Base material 4>
Specific examples of the base material 4 constituting the laminate of the present embodiment include polyolefin resins such as polyethylene and polypropylene; polyester resins such as polyethylene terephthalate, polyethylene naphthalate, polycarbonate, and polylactic acid; nylon 6 and nylon 12; Polyamide resins such as polystyrene, AS resin, ABS resin, etc., chlorine-containing resins such as polyvinyl chloride, polyvinylidene chloride, etc.; ethylene-vinyl alcohol copolymer resin; cellophane; paper; aluminum, stainless steel , a metal foil such as iron; or a film-like or sheet-like material made of a composite material thereof. In addition, in order to increase the durability, heat resistance, water resistance, light resistance, and gas barrier properties of the laminate, a composite material may be used. There are polyolefin-based resin films, polyester-based resin films, polyamide-based resin films, and the like. At that time, it is preferable that the deposited layer is in contact with the adhesive layer (III) in the laminate. Furthermore, as the base material 4, a laminate obtained by stacking a plurality of base materials exemplified above may be used. As a result, the heat resistance, gas barrier properties, etc. of the laminate can be further enhanced, and a more suitable flexible packaging material for food packages can be obtained.

The base material 4 to be used may be coated with polyvinyl alcohol or the like, or may be subjected to surface treatment such as corona treatment or plasma treatment.

The base material 4 constituting the laminate of the present embodiment preferably has an oxygen permeability of 100 cm ³ /m ² ·24 hrs·atm or less at 25°C. Among the substrates exemplified above, those with a high oxygen permeability per 1 μm (for example, polyamide resin) can be kept within the oxygen permeability range by increasing the thickness of the substrate during use. becomes. A composite material having a vapor deposition layer is less permeable to oxygen regardless of the thickness of the base material, and therefore can be suitably used in the laminate of the present embodiment.

The oxygen permeability can be measured according to the method of JIS K 7126 using an oxygen permeability measuring device (for example, MOCON oxygen permeability measuring device manufactured by Hitachi High-Tech Tens Co., Ltd.).

EXAMPLES Hereinafter, the laminates that are embodiments of the present invention will be described more specifically with reference to examples and comparative examples. In the following description, "parts" and "%" represent "parts by mass" and "% by mass", respectively, unless otherwise specified.

<Production example of binder resin 1>
A reaction vessel equipped with a gas inlet tube, a thermometer, a condenser and a stirrer was charged with 72.4 parts of 2-butanone and purged with nitrogen gas. The inside of the reaction vessel is heated to 80° C., and 4.5 parts of methacrylic acid as an ethylenically unsaturated monomer having an acid group, 5.0 parts of 2-hydroxyethyl methacrylate as an ethylenically unsaturated monomer having a hydroxyl group, A mixture of 90.5 parts of methyl methacrylate as other ethylenically unsaturated monomers and 12 parts of V-601 (manufactured by Wako Pure Chemical Industries, Ltd.) as a polymerization initiator was added dropwise over 2 hours to carry out a polymerization reaction. . After the completion of the dropwise addition, the reaction was further carried out at 80° C. for 3 hours, then 0.6 parts of V-601 (manufactured by Wako Pure Chemical Industries, Ltd.) was added, and the reaction was further continued at 80° C. for 2 hours to dissolve the binder resin 1 solution. Obtained. Using a TSKgel column (manufactured by Tosoh Corporation) and GPC (manufactured by Tosoh Corporation, HLC-8120GPC) equipped with an RI detector, the weight average molecular weight (Mw) of the binder resin 1 measured using THF as a developing solvent is about 7. ,000. After the solution of binder resin 1 was cooled to 50° C., 4.7 parts of dimethylaminoethanol was added for neutralization, and then 140 parts of water was added. After that, it is heated to 78° C. or higher to azeotropically distill 2-butanone with water, and then adjusted so that the solid content is 30%. got The acid value and hydroxyl value of the obtained binder resin 1 were calculated from the constituent units of the binder resin and were 29.3 (mgKOH/g) and 21.6 (mgKOH/g), respectively. Moreover, the glass transition temperature (Tg) was 103° C. as measured using a DSC (DSC6000, manufactured by PerkinElmer).

<Manufacturing Examples of Binder Resins 2, 3, and 21>
In order to adjust the weight average molecular weight, the binder resin 2 was prepared in the same manner as the binder resin 1, except that the amount of the polymerization initiator V-601 added was 4 parts, 2 parts, and 1.1 parts, respectively. , 3, and 21 were obtained at 30% solids.

<Production example of binder resin 20>
In order to adjust the weight average molecular weight, the reaction solvent was changed from 2-butanone to butanol, and the reaction temperature was 110°C. Further, an aqueous solution of binder resin 20 having a solid content of 30% was obtained in the same manner as for binder resin 1, except that the amount of polymerization initiator V-601 added dropwise was changed to 12 parts.

<Production Examples of Binder Resins 4 to 19, 22, 23, 40 to 43>
Binder resins 4 to 19, 22, 23, and 40 to 43 were made aqueous with a solid content of 30% by the same operation as binder resin 2 except that the monomers listed in Table 1 were used as polymerizable monomers. A solution was obtained. In the neutralization, dimethylaminoethanol was added so that the number of moles of amino groups in dimethylaminoethanol was equal to the number of moles of carboxyl groups of the ethylenically unsaturated monomer having a carboxyl group in the binder resin. . In addition, since the binder resin 41 that does not use an ethylenically unsaturated monomer having an acid group and an ethylene oxide group could not be rendered water-based, the subsequent evaluation was not performed.

<Production example of binder resin 24 (AB block polymer)>
20 parts of toluene as a polymerizable monomer, 5.0 parts of methacrylic acid as an ethylenically unsaturated monomer having an acid group, and other 5.0 parts of methyl methacrylate as an ethylenically unsaturated monomer, 0.9 parts of 2,2'-azobisisobutyronitrile as a polymerization initiator, 2-(dodecylthiocarbonothioylthio)-iso 3.6 parts of butyric acid were charged in each. After purging the inside of the reaction vessel with nitrogen gas, the temperature was raised to 75° C. and a polymerization reaction was carried out for 3 hours to obtain a copolymer (A block) composed of methacrylic acid and methyl methacrylate.

After the completion of the polymerization reaction, the reaction system was cooled to room temperature, and then 60 parts of toluene, 5.0 parts of 2-hydroxyethyl methacrylate as an ethylenically unsaturated monomer having a hydroxyl group, and other polymerizable As monomers, 60 parts of methyl methacrylate, 15 parts of stearyl methacrylate, and 10 parts of styrene were added. After purging the inside of the reaction vessel with nitrogen gas, the temperature was raised to 75° C., and the polymerization reaction was carried out for 3 hours to form a copolymer consisting of 2-hydroxyethyl methacrylate, methyl methacrylate, stearyl methacrylate, and styrene in the A block. A binder resin 24 having an AB block structure to which coalescence (block B) was added was obtained.

Then, after cooling the reaction system to room temperature, 6.2 parts of dimethylaminoethanol was added to the reactor for neutralization, and then 200 parts of water was added. Next, the resulting solution is heated to azeotrope toluene with water to distill off the toluene, and then adjusted with water so that the solid content becomes 30%, thereby obtaining an aqueous solution of the binder resin 24. rice field.

<Production Example of Binder Resin 44>
An aqueous solution of binder resin 44 (solid content: 30%) was obtained in the same manner as binder resin 24, except that the monomers shown in Table 2 were used as the polymerizable monomers.

<Production Example of Binder Resin 45>
A reaction vessel equipped with a gas inlet tube, a thermometer, a condenser and a stirrer was charged with 50 parts of ion-exchanged water and 0.2 parts of Aqualon KH-10 (manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) as an emulsifier. On the other hand, 70.5 parts of butyl acrylate, 20 parts of styrene, 4.5 parts of methacrylic acid, 5 parts of 2-hydroxyethyl methacrylate, 68 parts of deionized water and Aqualon KH-10 as an emulsifier (Daiichi Kogyo Seiyaku Co., Ltd.)1. Eight parts were separately stirred and mixed by a homomixer to obtain an emulsion.

Five portions of the emulsified liquid were taken and added to the reaction vessel described above. After the addition, the internal temperature was raised to 60° C. and the contents were sufficiently replaced with nitrogen, and then 3 parts of a 5% aqueous solution of potassium persulfate and 4 parts of a 1% aqueous solution of anhydrous sodium bisulfite were added to initiate polymerization. After starting the reaction, the rest of the above emulsion, 2 parts of a 5% aqueous solution of potassium persulfate, and 6 parts of a 1% aqueous solution of anhydrous sodium bisulfite were added dropwise over 1.5 hours while maintaining the internal temperature at 60°C. Stirring was continued for an additional 2 hours. After completion of the reaction, the temperature was cooled to 30° C. and diethylaminoethanol was added to adjust the pH to 8.5. Further, by adjusting the solid content to 30% with ion-exchanged water, an aqueous dispersion of the binder resin 45 (30% solid content) was obtained.

<Production Example of Binder Resin 46>
An aqueous dispersion of binder resin 46 having a solid content of 30% was obtained in the same manner as for binder resin 45, except that the monomers shown in Table 3 were used as the polymerizable monomers.

The abbreviations described in Tables 1 to 3 are as follows.
AA: acrylic acid MAA: methacrylic acid MOEPh: methacryloyloxyethyl phosphonic acid VSA: vinyl sulfonic acid 2HEMA: 2-hydroxyethyl methacrylate 2HEA: 2-hydroxyethyl acrylate 4HBA: 4-hydroxybutyl acrylate MMA: methyl methacrylate BMA: butyl methacrylate LMA : Lauryl methacrylate StMA: Stearyl methacrylate 2EHMA: 2-Ethylhexyl methacrylate BA: Butyl acrylate St: Styrene α-MeSt: α-methylstyrene

<Synthesis Example of Pigment Dispersion Resin 1>
A reaction vessel equipped with a gas inlet tube, a thermometer, a condenser and a stirrer was charged with 95 parts of butanol and purged with nitrogen gas. The inside of the reaction vessel was heated to 110° C., and 35 parts of styrene, 35 parts of acrylic acid, 30 parts of behenyl acrylate as polymerizable monomers, and V-601 (manufactured by FUJIFILM Wako Pure Chemical Industries, Ltd.) as a polymerization initiator were added. A mixture of 6 parts was added dropwise over 2 hours to carry out a polymerization reaction. After the dropwise addition, the mixture was further reacted at 110°C for 3 hours, 0.6 part of V-601 was added, and the reaction was further continued at 110°C for 1 hour to obtain a solution of Pigment Dispersion Resin 1. Furthermore, after cooling to room temperature, dimethylaminoethanol was added to completely neutralize the mixture, and then 100 parts of water was added to make it aqueous. Thereafter, the mixture was heated to 100° C. or higher to azeotrope butanol with water to distill off the butanol, and the solid concentration was adjusted to 30%. Thus, an aqueous solution of Pigment Dispersion Resin 1 having a solid content concentration of 30% was obtained. Pigment dispersion resin 1 had a weight average molecular weight of 28,000 and an acid value of 273 mgKOH/g.

<Production Example of Pigment Dispersion W>
40 parts of CR-90-2 (titanium oxide) manufactured by Ishihara Sangyo Co., Ltd., 30 parts of an aqueous solution of pigment dispersion resin 1 (solid content concentration 30%), and 30 parts of water are mixed. A pigment dispersion liquid W (white) was obtained by dispersing by the method.

<Production Example of Pigment Dispersion C>
20 parts of Toyocolor Lionol Blue 7358G (CI Pigment Blue 15:3), 15 parts of aqueous solution of pigment dispersion resin 1 (solid concentration: 30%), and 65 parts of water were mixed and mixed with a disper. After pre-dispersion, main dispersion was performed using a Dyno mill with a volume of 0.6 L filled with 1,800 g of zirconia beads with a diameter of 0.5 mm to obtain a pigment dispersion liquid C (cyan).

<Production example of ink 1W>
40 parts of pigment dispersion W (white), 20 parts of binder resin 1 (solid content concentration 30%), 23 parts of 1,2-propanediol, 1 part of adipic acid dihydrazide, 1.5 parts of TEGO WET 280 , 1 part of Surfynol 465, and 0.05 of Proxel GXL are successively added to a mixing vessel, then water is added to adjust the total ink to 100 parts, and the dispersion is sufficiently uniform. Stir until After that, filtration was performed with a membrane filter having a pore size of 1 μm to remove coarse particles that cause head clogging, and ink 1W was prepared.

<Manufacturing examples of inks 2W to 32W, 41W to 46W, 4C, and 42C>
Inks 2W-32W, 41W-46W, 4C and 42C were obtained in the same manner as ink 1W, except that the materials listed in Table 4 were used.

In addition, the abbreviations described in Table 4 are as follows.
PD: 1,2-propanediol BD: 1,2-butanediol HD: 1,2-hexanediol MB: 3-methoxybutanol DEDG: diethylene glycol diethyl ether TEGO WET 280: siloxane surfactant TEGO WET 500 manufactured by Evonik : Alkoxy alcohol-based surfactant Surfynol 465 manufactured by Evonik Co., Ltd. Acetylene diol-based surfactant BYK3400 manufactured by Shin-Etsu Chemical Co., Ltd. Anionic surfactant Surflon S243 manufactured by Big Chemie Co., Ltd. Fluorine-based surfactant Emulgen 707 manufactured by AGC Seimi Chemical Co., Ltd. : Polyoxyethylene alkyl ether manufactured by Kao Corporation ADH: Dihydrazide adipic acid Proxel GXL: Preservative manufactured by Lonza

<Production Example of Laminate Adhesive Composition>
A laminating adhesive composition was prepared according to the following procedure.
(1) After mixing a polyol (different from the polyol component (M)) and an isocyanate compound, the mixture is subjected to a urethanization reaction to produce an isocyanate component (K) having an isocyanate group at its end.
(2) Production of polyol component (M).
(3) Mixing an isocyanate component (K) containing a urethane prepolymer and a polyol component (M) to produce a laminate adhesive (J).
(4) In (3), ethyl acetate was mixed as necessary in order to impart coatability of the laminate adhesive composition.

<Synthesis example of isocyanate K1>
The following materials are put into a reaction vessel equipped with a stirrer, heated to 70° C. to 80° C. while stirring under a nitrogen gas stream, and the urethanization reaction is performed for 3 hours while maintaining the temperature in the vessel to isocyanate. A polyether polyisocyanate compound having a group (referred to as isocyanate K1) was obtained. The isocyanate group content of isocyanate K1 was 10.2%, and the aromatic isocyanate monomer content was 30%.
Polypropylene glycol (number average molecular weight about 400) 300 parts Polypropylene glycol (number average molecular weight about 2,000) 400 parts Triol obtained by adding polypropylene glycol to glycerin (number average molecular weight about 400) 200 parts 4,4'-diphenylmethane diisocyanate 400 parts 2,4'-diphenylmethane diisocyanate 600 parts

<Synthesis example of isocyanate K2>
80 parts of isophthalic acid, 460 parts of adipic acid, 60 parts of 1,6-hexanediol, and 400 parts of diethylene glycol are charged into a reaction vessel and heated to 150° C. to 240° C. under a nitrogen gas stream with stirring to increase the temperature in the vessel. The esterification reaction was carried out while maintaining When the acid value of the content reached 1.3 (mgKOH/g), the temperature inside the vessel was raised to 200°C, and then the pressure inside the reaction vessel was gradually reduced to 1.3 kPa or less. Then, the mixture was reacted for 30 minutes while maintaining the above temperature and pressure to obtain a polyester diol L having an acid value of 0.4 mgKOH/g, a hydroxyl value of 80 mgKOH/g, a number average molecular weight of about 1,400, and terminal hydroxyl groups.

160 parts of the obtained polyester diol L, 200 parts of PPG-400, 310 parts of 4,4'-MDI, and 350 parts of 2,4-MDI were charged into a reaction vessel different from the above. , under a nitrogen gas stream, heated to 70 ° C. to 80 ° C. with stirring, and urethanized for 3 hours while maintaining the temperature in the container, the isocyanate group content was 16.7%, containing an aromatic isocyanate monomer. A polyether polyisocyanate compound containing isocyanate groups (referred to as isocyanate K2) was obtained with a yield of 50%.

<Synthesis examples of isocyanates K3 to K7>
Isocyanates K3 to K7, which are polyether polyisocyanate compounds, were obtained in the same manner as for isocyanate K1, except that the raw materials shown in Table 5 were used.

<Synthesis example of isocyanate K8>
Isocyanate K8, which is a polyether polyisocyanate compound, was obtained in the same manner as for isocyanate K2, except that the raw materials shown in Table 5 were used.

In addition, the abbreviations described in Table 5 are as follows.
PPG-400: polypropylene glycol (number average molecular weight of about 400)
PPG-2000: polypropylene glycol (number average molecular weight of about 2,000)
PPG-400-3 functional: triol obtained by adding polypropylene glycol to glycerin (number average molecular weight of about 400)
4,4'-MDI: 4,4'-diphenylmethane diisocyanate 2,4'-MDI: 2,4'-diphenylmethane diisocyanate TDI: mixture of 2,4-tolylene diisocyanate and 2,6-tolylene diisocyanate XDI: xylene Diisocyanate HDI: hexamethylene diisocyanate IPDI: isophorone diisocyanate

Table 5 also shows the compounding molar ratio of each isocyanate compound, the isocyanate group (NCO group) content, the isocyanate monomer content, and the aromatic isocyanate monomer content for the isocyanates K1 to K8. was described.

<Production examples of polyols M1 to M9 and M21 to M23>
Polyester diols (referred to as N1 to N5, respectively) were synthesized in the same manner as in Synthesis Examples 201, 203, 205 to 207 described in JP-A-2017-177800. The physical properties of the obtained polyester diols N1 to N5 were as shown in Table 6.

Polyols M1 to M9 and M21 to M23 were obtained by mixing the polyester diols N1 to N5 obtained above with the materials and compounding amounts shown in Table 6. Table 6 also shows the hydroxyl values of polyols M1 to M9 and M21 to M23, and the number average molecular weight (Mn) of the entire polyol component (M).

Table 6 also shows the proportion (%) of polyester polyols or polyether polyols having a number average molecular weight of 500 to 3,200 in the total polyol component (M). First, the standard deviation σ was calculated from the obtained number average molecular weight and weight average molecular weight using the following formula (2).
Formula (2): standard deviation σ = [Mn (Mw - Mn)] 1/2
Using this standard deviation σ and the standard normal distribution table, the ratio of the number average molecular weight of 500 to 3,200 to the whole was calculated.

EXCENOL400, 1030, 230 and 4030 listed in Table 6 are polyether polyols manufactured by AGC. ETERNACOLL-PH100 is a polycarbonate diol manufactured by Ube Industries.

<Production Example of Laminate Adhesive Composition J1>
100 parts of the isocyanate component K1 obtained above and 50 parts of the polyol component M1 obtained above were mixed at 60° C. to obtain a laminate adhesive composition J1. The ratio of the number of moles of isocyanate groups in the isocyanate component of the laminate adhesive composition J1 to the number of moles of hydroxyl groups in the polyol component (NCO/OH ratio) is 1.3.

Here, the ratio of the number of moles of isocyanate groups to the number of moles of hydroxyl groups in the polyol component (NCO/OH ratio) was obtained by the following formula (3).
Formula (3): Amount of isocyanate groups per 100 moles of hydroxyl groups = [isocyanate groups (eq.) / hydroxyl groups (eq.)]

However, in formula (3),
Isocyanate group (eq.) = NCO group content (mass%) / 4200
and
Hydroxyl group (eq.) = hydroxyl value/56100
is.

In addition, the aromatic isocyanate compounds contained in the total amount of the laminate adhesive composition J1 were 4,4'-MDI and 2,4'-MDI, and the total ratio was 20%. Here, the aromatic isocyanate monomer content is the area of the peak derived from the 4,4'-MDI monomer (appearing around Mn = 200 to 300) observed on the GPC chart, and the area of the 2,4'-XDI monomer. It is obtained by dividing the total area of the derived peak (appearing around Mn=150 to 250) by the total area of all the peaks observed on the GPC chart.

<Production Examples of Laminate Adhesive Compositions J2 to J14 and J21 to J26>
Laminate adhesive compositions J2 to J14 and J21 to J26 were obtained in the same manner as laminate adhesive composition J1, except that the compositions shown in Table 7 were used. Table 7 also shows the ratio of the number of moles of isocyanate groups in the isocyanate component to the number of moles of hydroxyl groups in the polyol component (NCO/OH ratio) for each laminate adhesive composition.

[Examples 1 to 47, Comparative Examples 51 to 66]
<Example of printing with water-based inkjet ink>
An inkjet head KJ4B-1200 (manufactured by Kyocera Corporation, resolution 1200 dpi, maximum drive frequency 64 kHz) was installed above a conveyor capable of conveying the printing substrate, and filled with the water-based inkjet ink prepared above. Next, after fixing the transparent base material 1 on the conveyor, the conveyor is driven at 50 m/min, and water-based inkjet ink is discharged when passing through the installation part of the inkjet head, and the image shown below is obtained. I made two prints. The drop volume during printing was set to 2.5 pL, and the printed material was placed in an air oven at 70° C. and dried for 3 minutes.

<Print image 1>
After printing a nozzle check pattern and confirming that ink is being ejected normally from all nozzles, leave it for 1 minute in an environment of 25°C, then print at a frequency of 40 kHz and a print rate of 1200 x 1200 dpi. 100% solid printing was performed. At that time, the initial ejection property was evaluated by checking visually and with a magnifying glass whether or not a 100% solid printing start portion was printed. The evaluation criteria are as follows, and the ⊚ and ◯ evaluations are considered to be practically usable. As the transparent substrate 1, a PET film (FE2001, thickness 12 μm) manufactured by Futamura Chemical Co., Ltd. was used.
◎: No chipping was observed at the beginning of striking even when visually checked and with a magnifying glass. ◯: No chipping was observed visually, but a chipping of less than 1 mm was confirmed when confirmed with a magnifying glass. △: Visually. Chipping of 1 mm to less than 5 mm was confirmed at the start of hitting ×: Chipping of 5 mm or more was confirmed at the start of hitting by visual inspection

<Print image 2>
Using the same printing conditions and the same base material as in Print Image 1, solid printing was first performed with a print rate of 100%. After solid printing, the inkjet ejection device was put on standby for a certain period of time in an environment of 25° C., then a nozzle check pattern was printed, and intermittent ejection properties were evaluated by visually confirming whether or not the nozzles were missing. The evaluation criteria are as follows, and the ⊚ and ◯ evaluations are considered to be practically usable.
◎: No nozzle missing even after printing after waiting for 2 hours ○: No nozzle missing even after printing after waiting for 1 hour, but nozzle missing occurs after printing after waiting for 2 hours △: 1 to 9 missing nozzles occurred after printing after waiting for 1 hour ×: 10 or more missing nozzles occurred after printing after waiting for 1 hour

<Production Example of Laminate>
Using the same printing conditions as for printed image 1, solid printing was performed on transparent base material 1 shown below at a print rate of 100%. Using a test coater, the laminate adhesive composition was applied to the surface of the ink layer (II) on the printed material under the conditions of a temperature of 60 ° C. and a coating speed of 50 m / min (coating amount: 2 g / m ² ) to prepare a precursor of the adhesive layer. After superimposing the substrate 4 on the precursor of the adhesive layer so as to have the layer structure shown in Table 8, the laminate was aged for 1 day in an environment of 25 ° C. and 80% RH. The adhesive composition was cured to produce a laminate.
Transparent substrate 1
・PET film “FE2001” manufactured by Futamura Chemical Co., Ltd.
(Thickness 12 μm, described as “PET” in Table 8 below and below)
・Nylon film “Emblem ON” manufactured by Unitika
(Thickness 15 μm, described as “NY” in Table 8 below and later)
Base material 4
・Unstretched polypropylene film “FHK2” manufactured by Futamura Chemical Co., Ltd.
(Thickness 25 μm, described as “CPP” in Table 8 below and below)
・Linear low-density polyethylene film “TUX-FC-D” manufactured by Mitsui Chemicals Tohcello
(Thickness 40 μm, described as “LLDPE” in Table 8 below and below)

For the laminate adhesive containing a solvent component, the coating amount was set to 3 g/m ² and the solvent component was dried after coating to prepare a precursor of the adhesive layer.

Table 8 shows the combination of the transparent substrate 1, water-based ink, lamination adhesive composition, and substrate 4 used to prepare each laminate.

In addition, in Example 47, Comparative Examples 65, and 66, after printing with cyan ink at a printing rate of 100%, a laminate was made. FIG. 1 is a schematic diagram showing a laminate produced from overprinted prints. Table 9 shows the combinations of transparent substrate 1, water-based ink, lamination adhesive composition, and substrate 4 used in this process.

Each laminate produced above was evaluated as follows. The evaluation results were as shown in Tables 8 and 9 together with the results of the initial ejection performance evaluation and the intermittent ejection performance evaluation.

<Evaluation of color unevenness>
Regarding the laminate produced using the printed image 1, the degree of color unevenness was evaluated by visually observing from the transparent substrate 1 side. The evaluation criteria are as follows, and ⊚ and ∘ are defined as practically usable ranges.
◎: Color unevenness in the solid part was not observed ○: Slight color unevenness was visually observed ×: Clear color unevenness was visually observed

<Evaluation of omission of solid area>
Regarding the layered product produced using the printed image 1, the degree of removal was evaluated by checking the degree of removal with a magnifying glass and visual observation from the transparent base material 1 side. The evaluation criteria are as follows, and ⊚ and ∘ are defined as practicable regions.
◎: Missing was not seen with a loupe and visually ○: Missing was slightly seen with a loupe, but not visually observed ×: Missing was seen visually

<Adhesion evaluation 1>
A laminate prepared using the printed image 1 was cut into a length of 300 mm and a width of 15 mm to obtain a test piece. Using an Instron type tensile tester, the T-peel strength (N) between the transparent substrate 1 and the substrate 4 was measured by pulling at a peel speed of 300 mm/min under an environment of 25°C. This test was performed 5 times and the average value was obtained to evaluate the adhesive strength. The evaluation criteria are as follows, and the ⊙ and ◯ evaluations are considered to be practically usable areas.
◎: Adhesive strength 1.5 N or more ○: Adhesive strength 0.6 N or more and less than 1.5 N △: Adhesive strength 0.3 N or more and less than 0.6 N ×: Adhesive strength less than 0.3 N

<Adhesion evaluation 2>
Two laminates prepared using the printed image 1 are superimposed on the substrate 4 side so that the transparent substrate 1 is on the outside, and a heat sealer is used at 150° C., 2 kg/cm ² , 1 second. A tare was prepared by sealing with This was sterilized with hot water at 95° C. for 30 minutes using a high-temperature and high-pressure cooking sterilization tester “RCS-40RTGN” manufactured by Nissaka Seisakusho. After the test, the evaluation was performed in the same manner as in Evaluation 1 of the adhesive force.

<Appearance evaluation>
The appearance of the laminate used in Evaluation 2 of Adhesive Strength was evaluated by visually observing from the side of the transparent substrate 1 . The evaluation criteria are as follows, and the ⊙ and ◯ evaluations are considered to be practically usable areas.
◎: Yuzu skin-like pattern and small spot-like pattern are not confirmed 〇: Small spot-like pattern is not confirmed, but some yuzu skin-like pattern is confirmed △: Small spot-like pattern, yuzu skin-like pattern Both patterns are somewhat confirmed ×: Many small spot-like patterns and yuzu skin-like patterns are confirmed

In Comparative Example 51, the hydroxyl value of the binder resin (B) is less than 3 mgKOH/g, and in Comparative Examples 52 to 54, 57, 64, and 65, as a structural unit, an ethylenically unsaturated monomer containing a hydroxyl group ( Since b2) was not included, the cross-linking reaction with the laminate adhesive composition (J) and the hydrogen bonding strength were inferior, resulting in inferior adhesive strength of the laminate. In particular, deterioration of adhesive strength and poor appearance after hot water treatment resulted in poor results. In Comparative Examples 55 and 56, the binder resin (B) does not belong to the water-based resin of the present invention, the weight average molecular weight is unmeasurably high, and the ejection property from the nozzle of the inkjet head is poor. As a result, color unevenness and missing solid portions occurred. In Comparative Examples 58 to 60, 64, and 66, the NCO/OH ratio, which is the ratio of the number of moles of isocyanate groups in the isocyanate component (K) of the laminate adhesive composition to the number of moles of hydroxyl groups in the polyol component (M), was It is out of the range of 1.0 to 3.0, resulting in inferior adhesive strength of the laminate after hot water sterilization. Comparative Examples 61 and 62, in which the number average molecular weight of the polyol component (M) was out of the range of 500 to 3,200, resulted in inferior adhesive strength of the laminate. In Comparative Example 63, since the polyol component (M) did not contain polyester polyol or polyether polyol, the adhesive strength of the laminate was inferior.

On the other hand, Examples 1 to 47 are systems using suitable water-based inks and lamination adhesives, and have a suitable layer structure of transparent substrate 1, ink layer (II), adhesive layer (III), and substrate 4. As a result, it is possible to obtain printed matter with excellent ejection properties from the nozzles of the inkjet head, print quality without color unevenness and lack of solid areas, and the adhesive strength as a laminate is also excellent. all remained in good condition, and all were within the practicable range.

1: transparent substrate 1
2a: cyan ink layer 2b: white ink layer 3: adhesive layer 4: substrate 4

Claims (4)

A method for producing a laminate having a transparent substrate 1, an ink layer (II), an adhesive layer (III), and a substrate 4 in this order, comprising the following steps (1) to (4). , a method for producing a laminate.
(1) A step of printing a water-based inkjet ink (A) on a transparent substrate 1 by an inkjet printing method and then drying to obtain an ink layer (II) having a thickness of 0.2 to 20 μm.
However, the water-based inkjet ink (A) contains a binder resin (B), a pigment , a water-soluble organic solvent, and a surfactant ,
The binder resin (B) has a hydroxyl value of 3 to 50 mgKOH/ g, an acid value of 10 to 60 mgKOH/g, a weight average molecular weight of 5,000 to 45,000, and a glass transition temperature (Tg) of 35 to 110 ° C., and the binder resin (B) is derived from a structural unit derived from an ethylenically unsaturated monomer (b1) containing an acid group, and an ethylenically unsaturated monomer (b2) containing a hydroxyl group. A water-soluble resin containing a structural unit that
The content of the binder resin (B) is 1 to 20% by mass in terms of non-volatile content with respect to the total amount of the water-based inkjet ink (A),
When the water-based inkjet ink (A) is other than white ink, the content of the pigment is 2 to 20% by mass with respect to the total amount of the water-based inkjet ink (A), and the water-based inkjet ink (A) is white. In the case of ink, the content of the pigment is 5 to 40% by mass with respect to the total amount of the water-based inkjet ink (A),
The content of the water-soluble organic solvent is 3 to 40% by mass with respect to the total amount of the water-based inkjet ink (A),
The content of the surfactant is 0.05 to 5.0% by mass with respect to the total amount of the water-based inkjet ink (A).
(2) A step of forming an adhesive layer precursor comprising the laminate adhesive composition (J) on the ink layer (II) and/or the substrate 4 .
However, the laminate adhesive composition (J) contains a polyol component (M) and an isocyanate component (K), and the number of moles of isocyanate groups in the isocyanate component (K) and the number of moles of the polyol component (M) The NCO/OH ratio, which is the ratio to the number of moles of hydroxyl groups, is in the range of 1.0 to 3.0, the polyol component (M) has a number average molecular weight of 500 to 3,200, polyester polyol, Alternatively, it contains a polyether polyol .
(3) A step of superimposing the ink layer (II) and the substrate 4 through the precursor of the adhesive layer.
(4) A step of curing the precursor of the adhesive layer to form the adhesive layer (III). 2. The method for producing a laminate according to claim 1, wherein the binder resin (B) has a hydroxyl value of 10 to 45 mgKOH/g. 3. The method for producing a laminate according to claim 1, wherein the polyol having a molecular weight of 500 to 3,200 accounts for 25% by mass or more of the total polyol component (M). The method for producing a laminate according to any one of claims 1 to 3 , wherein the isocyanate component (K) contains a urethane prepolymer compound obtained by reacting an aromatic isocyanate and a polyether polyol.

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