WO2024171965A1 - Multilayer body - Google Patents

Abstract

The present invention provides a multilayer body which exhibits high adhesion to print layers that are formed of various inks, and which has high gas barrier properties. This multilayer body is obtained by stacking, on at least one surface of a base material film, a metal layer and/or an inorganic compound layer, and a coating layer in this order. With respect to this multilayer body, the ratio X/Y of the emission intensity X of an emission peak to the emission intensity Y of a reference peak is 5 to 300.

Description

Laminate

The present invention relates to a laminate that has excellent adhesion to a printing layer.

Packaging materials for food, medicines, daily necessities, etc. require oxygen and water vapor barrier properties to prevent deterioration of the contents. Barrier films made of resin films such as polyester with a metal layer such as aluminum or a metal oxide layer laminated onto them have been used as barrier packaging materials. In particular, when a metal oxide layer is laminated onto a transparent film, it has good visibility, and when packaging food, it can be heated in a microwave oven, making it highly convenient, and so it is widely used. These films can be printed with characters, pictures, etc. for display purposes, or laminated with other resin films, making them suitable for use as packaging materials for a variety of purposes.

　In addition, to prevent deterioration of the gas barrier performance, a protective layer is sometimes laminated on top of the gas barrier layer, and generally printing is performed on the protective layer.

The printing method used for such protective layers is gravure printing, which is the mainstream method for printing on flexible packaging, because it has excellent printability and adhesion to the protective layer (Patent Document 1). However, gravure printing uses ink that contains a large amount of solvent, so a large amount of energy is required to dry the ink solvent and to treat the exhaust, which places a large burden on the environment.

In recent years, attempts have been made to use EB flexographic printing and EB offset printing, which cure ink by exposure to active energy rays, particularly electron beams (EB), in flexible packaging printing (Patent Document 2). Generally, flexible packaging printing is performed using a roll-to-roll method, so the quick drying of the ink is important, and active energy ray curing printing methods are not only environmentally advantageous because they contain almost no solvents, but also energy-saving and highly productive because they shorten the drying process without using thermal energy. In addition, curing by electron beam irradiation has excellent transparency and does not require a photopolymerization initiator in the ink, reducing the risk of odors on the printed material and migration of initiator decomposition components to the contents, and is also excellent in terms of safety in terms of protecting the contents.

However, active energy beam-curable inks, which are mainly composed of acrylate, have poor adhesion to protective layers. For this reason, a laminate has been reported that has excellent adhesion to active energy beam-curable inks by introducing a silicon alkoxide having a (meth)acrylate group into the protective layer as well (Patent Document 3).

International Publication No. 2018/3596 International Publication No. 2019/69736 JP 2022-20129 A

In the invention described in Patent Document 3, the amount of silicon alkoxide having a (meth)acrylate group introduced is very large, and adhesion to active energy ray-curable ink is obtained, but in consideration of other protective layer components such as highly hydrophilic vinyl alcohol resins and silicon alkoxides with small molecular weights, the introduction of a large number of highly hydrophobic and large molecular weight (meth)acrylate groups increases voids in the film and the film cannot be cured densely enough to suppress deterioration of the contents, which is not sufficient to obtain barrier properties and leaves room for improvement. Furthermore, because the amount of silicon alkoxide having a (meth)acrylate group introduced is very large, there is an issue of reduced adhesion to drying inks other than active energy ray-curable inks (solvents and water as a medium are thermally dried).

The objective of the present invention is to provide a laminate that exhibits high adhesion to printed layers made of various inks and also exhibits high gas barrier properties.

A preferred embodiment of the present invention is as follows.
(1) A laminate in which a metal layer and/or an inorganic compound layer and a coating layer are laminated in this order on at least one surface of a base film, in which the ratio X/Y of the emission intensity X of an emission peak to the emission intensity Y of a reference peak measured under the following measurement conditions from the coating layer side is 5 or more and 300 or less.
<Measurement conditions>
The coating layer side of the laminate was brought into contact with a 1× ^10-4 mol/L solution of 4-Nitro-7-piperazino-2,1,3-benzoxadiazole in THF (tetrahydrofuran) at 60°C for 30 minutes, and the laminate was then immersed and washed twice in THF. Thereafter, a piece was cut to a size of 15 mm×15 mm. In the emission spectrum measurement, the sample was excited at 470 nm, and the peak intensity of the emission maximum observed at 520 to 550 nm was calculated.
<Base Peak>
A 1×10 ⁻⁵ mol/L THF solution of 4-Nitro-7-piperazino-2,1,3-benzoxadiazole was measured in a quartz glass cell with an optical path length of 10 mm in the same manner as for the laminate.
(2) The laminate according to (1), wherein the coating layer contains a hydrolysate of a water-soluble resin and a metal alkoxide and/or a polycondensate thereof.
(3) The laminate according to (1) or (2), wherein the thickness of the coating layer is 200 nm or more and 600 nm or less.
(4) The laminate according to any one of (1) to (3), wherein the metal layer and/or the inorganic compound layer contains aluminum.
(5) The laminate according to any one of (1) to (4), wherein the laminate has a water vapor permeability of 1.0 g/m ² /day or less and an oxygen permeability of 1.0 cc/m ² /day or less.
(6) The laminate according to any one of (2) to (5), wherein the coating layer contains 0.25 mol % or more and 1.25 mol % or less of (meth)acryloyl groups relative to the total molar amount of metal elements contained in the coating layer.
(7) The laminate according to any one of (1) to (6), wherein the ratio X/Y of the emission intensity X of an emission peak to the emission intensity Y of a reference peak measured under the following measurement conditions from the coating layer side of the laminate is 18 or more and 100 or less.
<Measurement conditions>
The coating layer side of the laminate was brought into contact with a 1× ^10-4 mol/L THF solution of 4-Nitro-7-piperazino-2,1,3-benzoxadiazole at 60° C. for 30 minutes, and the laminate was then immersed and washed twice in THF. Thereafter, a 15 mm×15 mm piece was cut out and the emission spectrum was measured by exciting at 470 nm, and the peak intensity of the emission maximum observed at 520 to 550 nm was calculated.
<Base Peak>
A 1×10 ⁻⁵ mol/L THF solution of 4-Nitro-7-piperazino-2,1,3-benzoxadiazole was measured in a quartz glass cell with an optical path length of 10 mm in the same manner as for the laminate.
(8) The laminate according to any one of (1) to (7), wherein the base film is a polyolefin-based resin film.
(9) The laminate according to any one of (1) to (8), wherein the ratio P1/P2 of the following peak intensities P1 and P2 detected by measuring the coating layer by an FT-IR-ATR method (total reflection Fourier transform infrared spectroscopy) is 3.5 or more and 8.0 or less.
P1: Intensity of the maximum peak present at 1,050 to 1,080 cm ^-1 P2: Intensity of the maximum peak present at 920 to 970 cm ^-1 (10) The laminate according to any one of (1) to (9), wherein the coating layer contains a metal element M in addition to a water-soluble resin and a hydrolysate of a metal alkoxide and/or a polycondensate thereof, and the ratio m/s of the peak intensity m of a fragment ion derived from the metal element M to the peak intensity s of a fragment ion derived from a segment having a Si-O bond, as measured by a time-of-flight secondary ion mass spectrometer (TOF-SIMS), is 0.05 or more and 10.00 or less.
<Measurement conditions>
Primary ion species: Bi ⁺ (2 pA, 50 μs)
Acceleration voltage: 25 kV
Detected ion polarity: positive
Measurement range: 100 μm x 100 μm
Resolution: 128×128
Etching ion species: O ²⁺ (2 keV, 170 nA)
Etching area: 300 μm × 300 μm
Etching rate: 1 sec/cycle
(11) The laminate according to any one of (1) to (10), wherein the base film is a film derived from recycling.
(12) The laminate according to any one of (1) to (11), which is used for packaging material applications.
(13) The laminate according to any one of (1) to (12), which is used for printing with an electron beam curable ink.

The present invention makes it possible to provide a laminate that exhibits high adhesion to printed layers made of various inks and also exhibits high gas barrier properties.

1 is a schematic cross-sectional view showing a configuration of a laminate of the present invention.

Below, a preferred embodiment of the laminate of the present invention will be described in more detail.

Substrate Film The resin constituting the substrate film according to the present invention is not particularly limited, and examples thereof include polyester resins such as polyethylene terephthalate, polyethylene-2,6-naphthalate, polypropylene terephthalate, and polybutylene terephthalate; polyolefin resins such as polyethylene, polystyrene, polypropylene, polyisobutylene, polybutene, and polymethylpentene; cyclic polyolefin resins, polyamide resins, polyimide resins, polyether resins, polyesteramide resins, polyetherester resins, acrylic resins, polyurethane resins, polycarbonate resins, and polyvinyl chloride resins; and biodegradable resins such as polylactic acid, polycaprolactone, polyglycolic acid, and polyvinyl alcohol. Among these, polyester resins are preferred from the viewpoint of adhesion to the inorganic compound layer and handling, and polyolefin resins are preferred from the viewpoint of ease of recycling. In addition to recyclability, it is preferable that the resin contains 3 to 55% by mass of recycled raw materials relative to the entire resin. The recycled raw materials may be those recycled by mechanical recycling or chemical recycling, and are not particularly limited. Furthermore, the resin constituting the base film may contain a biomass-derived (plant-derived) raw material, and for example, in the case of polyester, it is preferable that either one or both of the raw materials, diol or dicarboxylic acid, contain 10 to 95 mass % of a biomass-derived (plant-derived) raw material with respect to the entire resin composition. The base film may be unstretched or stretched (monoaxially or biaxially), but is preferably biaxially stretched from the viewpoint of thermal dimensional stability.

The thickness of the base film is preferably 3 μm or more and 100 μm or less, more preferably 5 μm or more and 50 μm or less, and even more preferably 8 μm or more and 30 μm or less. A thickness of 3 μm or more of the base film allows the rigidity of the support to be maintained, while a thickness of 100 μm or less is preferable because it maintains the flexibility of the film as a packaging material while improving conformability. The thickness of the base film is determined by the method described in the examples.

The polyolefin resin film used for the base film is preferably a film mainly composed of a resin whose main constituent unit is an olefin hydrocarbon. The main constituent unit refers to the monomer unit contained in the resin that has the highest content (unit number), and the main component refers to the monomer unit contained in the resin that has the highest content (mass%) among all the constituent components. Examples of polyolefin resins include, in addition to ethylene, polymers of α-olefins having alkyl groups on the side chains such as propylene and 4-methyl-1-pentene, and copolymers thereof, or copolymers obtained by copolymerizing α-olefins with acrylic acid, C=C bond-containing carboxylic acid, C=C bond-containing carboxylate, C=C bond-containing carboxylate alkyl ester, etc., polymers of norbornene and cyclodiene, and polymers thereof, which may be single-layered or multi-layered. Among these, it is preferable to include polyethylene or polypropylene because they are relatively inexpensive, and it is more preferable to include polypropylene in terms of heat resistance, and it is even more preferable to use polypropylene as the main component from the same viewpoint. In addition, the film may be unstretched or stretched, but it is preferable to be biaxially stretched from the viewpoint of thermal dimensional stability. The polyolefin resin film preferably has a melting point of 150°C or higher. By setting the melting point at 150°C or higher, heat damage caused by the heat during the process of forming the metal oxide layer or processing into a packaging material can be prevented, and the heat resistance after processing is also increased, so deterioration of the barrier properties can be suppressed. The melting point of the film can be measured by DSC (differential scanning calorimetry) using the following method.

<Method of measuring the melting point of the film>
Using a differential scanning calorimeter (EXSTAR DSC6220 manufactured by Seiko Instruments Inc.), a 3 mg sample is heated from 30°C to 260°C in a nitrogen atmosphere at a heating rate of 20°C/min, then held at 260°C for 5 minutes, and cooled to 30°C at a rate of 20°C/min. After being held at 30°C for 5 minutes, the sample is heated again from 30°C to 260°C at a rate of 20°C/min, and the peak temperature of the endothermic curve obtained during this heating again is taken as the melting point of the resin composition. When multiple peak temperatures are observed, the highest temperature is taken as the melting point of the resin composition.

The glass transition temperature (Tg) of the polyolefin resin film is preferably 50°C or lower. This embodiment increases the flexibility of the film even at low temperatures, and when used as a package, it does not harden even at low temperatures, allowing for stable use over a wide temperature range.

Furthermore, it is preferable that the polyolefin resin film has a smooth surface. Surface smoothness can be expressed by the arithmetic mean height Sa defined in ISO25178 (2012), and Sa is preferably 50 nm or less, more preferably 30 nm or less. Sa can be measured using a non-contact surface observation device, for example, a scanning white light interference microscope manufactured by Hitachi High-Tech Science Corporation. In the present invention, Sa is determined by the method described in the examples. By making the surface smooth, defects in the inorganic oxide layer laminated on the surface can be reduced, a good inorganic oxide layer can be obtained, and the barrier properties can be improved.

Metal Layer and/or Inorganic Compound Layer The laminate of the present invention preferably has a metal layer and/or an inorganic compound layer on at least one surface of the substrate film.

The metal layer and/or the inorganic compound layer preferably contains one or more elements selected from Groups 2 to 14 (excluding carbon) of the periodic table, and the inorganic compound layer further contains at least one of oxygen and nitrogen. Among these, from the viewpoint of processing cost and gas barrier properties, the metal layer preferably contains aluminum, and more preferably has aluminum as the main component. The main component refers to the component that has the largest content (mass%) among the components. From the same viewpoint, the inorganic compound layer preferably contains at least one or more selected from aluminum, magnesium, titanium, tin, indium, and silicon, and more preferably contains silicon or aluminum. Examples of preferable inorganic compound layers include silicon oxide, silicon oxynitride, and aluminum oxide, and aluminum oxide is particularly preferable. Furthermore, in the inorganic oxide layer, the ratio of aluminum to the total of elements from Groups 2 to 14 (excluding carbon) of the periodic table is preferably 50 atomic % or more.

If a metal layer is present, the thickness of the metal layer is preferably 5 nm or more and 500 nm or less, and more preferably 10 nm or more and 100 nm or less. A thickness of 5 nm or more can improve the barrier properties, and a thickness of 500 nm or less is preferable because it can prevent the substrate from being damaged by heat during film formation.

If an inorganic compound layer is present, the thickness of the inorganic compound layer is preferably 2 nm to 50 nm, more preferably 2 nm to 20 nm, and even more preferably 4 nm to 10 nm. A thickness of 2 nm or more can reduce defects such as pinholes in the inorganic compound layer, and a thickness of 50 nm or less can suppress cracks, which is preferable.

The thickness of the metal layer and inorganic compound layer will be determined by the method described in the examples.

The laminate of the present invention is preferably a laminate in which a metal layer and/or an inorganic compound layer, and a coating layer are laminated in this order on at least one surface of a base film. This embodiment includes a laminate in which a base film, a metal layer, and a coating layer are laminated in this order, a laminate in which a base film, an inorganic compound layer, and a coating layer are laminated in this order, as well as a laminate in which a base film, a metal layer, an inorganic compound layer, and a coating layer are laminated in this order, a laminate in which a base film, an inorganic compound layer, a metal layer, and a coating layer are laminated in this order, and a laminate in which a base film, an inorganic compound layer, a metal layer, and a coating layer are laminated in this order.

Coating Layer In the present invention, the coating layer refers to at least one outermost layer of the laminate, and is preferably a layer containing a water-soluble resin and a hydrolysate of a metal alkoxide and/or a polycondensate thereof.

The laminate of the present invention is preferably a laminate in which a metal layer and/or an inorganic compound layer and a coating layer are laminated in this order on at least one surface of a base film, the coating layer is preferably a layer containing a water-soluble resin and a hydrolysate of a metal alkoxide and/or a polycondensate thereof, and the outermost layer is preferably the coating layer.

Water-soluble resin refers to a resin that is dispersed in water to a concentration of 5% by mass, heated and stirred at 90°C for 1 hour, and then cooled to room temperature. When 30 mL of the liquid is passed through filter paper type 1 (compliant with JIS P 3801 (1995)), no residue remains on the filter paper.

The water-soluble resin of the coating layer preferably contains one or more segments selected from a segment derived from a vinyl alcohol resin, a segment derived from a polysaccharide, and a segment derived from an acrylic polyol resin.

Preferred examples of resins containing segments derived from vinyl alcohol resins, segments derived from polysaccharides, and segments derived from acrylic polyol resins are vinyl alcohol resins, polysaccharides such as methyl cellulose, and acrylic polyol resins, respectively, with vinyl alcohol resins being preferred in terms of improved oxygen barrier properties. Examples of vinyl alcohol resins include polyvinyl alcohol, ethylene-vinyl alcohol copolymers, and modified polyvinyl alcohol, and these resins may be used alone or in mixtures of two or more. The average molecular weight of the vinyl alcohol resin (in accordance with JIS K 6726 (1994)) is preferably 500 or more and 3,000 or less. If the molecular weight is smaller than this, the polymer is less likely to be fixed in the layer, and the barrier properties may be reduced.

Vinyl alcohol resins are generally obtained by saponifying polyvinyl acetate. They may be partially saponified by saponifying some of the acetate groups, or completely saponified, but a higher degree of saponification is preferable. The degree of saponification (based on JIS K 6727 (1994)) is preferably 90% or more, and more preferably 95% or more. A higher degree of saponification means fewer acetate groups with large steric hindrance, a smaller free volume for the coating layer, and a higher degree of crystallization of the resin, which is advantageous for improving barrier properties and is therefore preferable.

Modified polyvinyl alcohol resins are those made by chemically reacting polyvinyl alcohol with monomers of different chemical structures, or by copolymerizing monomers of different chemical structures. Modified polyvinyl alcohol resins include vinyl esters such as vinyl acetate and vinyl propionate, carboxylic acids, methacrylic esters, vinyl ethers such as methyl vinyl ether, and glycols.

The segments derived from the vinyl alcohol resin, the polysaccharide, and the acrylic polyol resin contained in the coating layer can be analyzed by the following method.

The film piece is immersed in deuterated isopropanol, and the coating layer composition is dissolved in the solvent, or the coating layer is physically scraped off using a spatula or the like. Whether the coating layer has been dissolved or scraped off can be confirmed by measuring the thickness of the coating layer in the same manner as in the thickness evaluation method described below. Next, the sample dissolved in the solvent is analyzed by liquid NMR, or the scraped sample is analyzed by solid NMR for ¹³ C, and it can be confirmed whether each segment is included by assigning each peak.

The metal alkoxide is one or more selected from silicon alkoxides represented by Si(OR) ₄ , hydrolysates of silicon alkoxides, and polycondensates of hydrolysates of silicon alkoxides, which become segments having Si-O bonds, and/or is represented by the general formula M(OR) _n . In the formula, n is a natural number, and M is a metal atom, preferably titanium, aluminum, zirconium, etc. Here, R is an alkyl group, and in particular, a lower alkyl group having 1 to 4 carbon atoms is preferable. In particular, from the viewpoints of reactivity, stability, and cost, for example, tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, and tetrabutoxysilane can be preferably used, and these may be used alone or in a mixture of two or more kinds. These metal alkoxides may be hydrolyzed or polycondensed to form a network.

The hydrolysis and/or polycondensation of the metal alkoxide can be carried out in the presence of water, a catalyst, and an organic solvent. The amount of water used in the reaction is preferably 0.8 equivalents or more and 5 equivalents or less relative to the alkoxy groups of Si(OR) ₄ and/or M(OR) _n . By setting the amount of water to 0.8 equivalents or more, it is preferable that the hydrolysis can be sufficiently advanced to form a network. By setting the amount of water to 5 equivalents or less, it is preferable that the degree of hydrolysis can be adjusted to suppress random network formation, and the free volume of the film can be reduced to improve the barrier property.

The catalyst used for the reaction of the metal alkoxide is preferably an acid catalyst. Examples of acid catalysts include, but are not limited to, hydrochloric acid, sulfuric acid, nitric acid, phosphoric acid, acetic acid, tartaric acid, etc. Usually, the hydrolysis and polycondensation reaction of the metal alkoxide can be carried out with either an acid catalyst or a base catalyst. When an acid catalyst is used, the monomers in the system are easily hydrolyzed on average, and condensation is likely to proceed in a linear or network structure. On the other hand, when a base catalyst is used, the reaction mechanism is such that the hydrolysis and polycondensation reaction of alkoxides bonded to the same molecule is easily promoted, so the reaction product tends to be granular with a large free volume and many voids. Since the voids in the film become a permeation path for water vapor and oxygen, it is preferable to use an acid catalyst. The amount of catalyst used is preferably 0.1 mol% to 0.5 mol% of the total molar amount of the metal alkoxide.

The organic solvent used in the reaction of the metal alkoxide can be water and alcohols that are miscible with the metal alkoxide, such as methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, and n-butyl alcohol.

Commercially available silicate oligomers and polysiloxanes can also be used as polycondensates of metal alkoxides. Although silicate oligomers and polysiloxanes can be used alone or mixed with low molecular weight metal alkoxides, it is preferable to use them mixed with low molecular weight metal alkoxides to prevent cracks caused by excessive crosslinking. When using silicate oligomers or polysiloxanes, it is preferable to select those with a linear or network structure, as this reduces the free volume of the film and tends to improve the barrier properties.

The metal alkoxide contained in the coating layer can be analyzed by FT-IR-ATR analysis of the coating layer surface, and by assigning each peak, it can be confirmed whether or not the coating layer contains segments with Si-O bonds and M-O bonds.

The coating layer in the present invention is preferably obtained by mixing the water-soluble resin with the hydrolysis and/or polycondensation product of the metal alkoxide, and applying and drying the coating agent to the metal layer and/or _inorganic compound layer. The ratio of the resin and the hydrolysis product and/or polycondensation product of the metal alkoxide contained in the coating layer is preferably in the range of 15/85 to 85/15, more preferably in the range of 20/80 to 65/35, more preferably _in the range of 20/80 to 50/50, and particularly preferably in the range of 20/80 to 40/60, in terms of the mass ratio of the resin to the mass (converted mass of SiO 2 and MO n) when the central atom of the metal alkoxide is completely oxidized. By making this ratio 15/85 or more, it is possible to suppress the occurrence of cracks due to the weakening of the film caused by an excess amount of the hydrolysis product and/or polycondensation product of the metal alkoxide, which is preferable. By making the ratio 85/15 or less, the resin can be fixed by a network of a hydrolysate and/or a polycondensate of the metal alkoxide, and deterioration of the water vapor barrier property can be suppressed, which is preferable.

The coating layer in the present invention is preferably prepared by adding a silane coupling agent having a (meth)acryloyl group to the coating agent obtained by mixing the water-soluble resin with the hydrolysis and/or polycondensation product of the metal alkoxide, which makes it possible to introduce a (meth)acryloyl group into the coating layer. By having a (meth)acryloyl group in the coating layer, when a printing layer is formed on the coating layer using an active energy ray-curable ink, the (meth)acryloyl group in the coating layer and the active energy ray-curable ink can be crosslinked by radical polymerization, improving the adhesion between the coating layer and the printing layer.

The (meth)acryloyl group is preferably 0.25 mol% or more, more preferably 0.30 mol% or more, based on the total molar amount of metal elements contained in the coating layer, since it improves the film adhesion of active energy ray-curable ink. Also, since the gas barrier properties are well maintained, it is preferably 1.25 mol% or less, more preferably 1.10 mol% or less. This is because the (meth)acryloyl group has a large free volume compared to alkoxides having 4 or less carbon atoms and hydroxyl groups which are their hydrolysates, and as the amount added increases, the voids in the coating layer expand, which may result in a decrease in gas barrier properties. Also, as the amount of (meth)acryloyl group added increases, the number of hydroxyl groups decreases accordingly, which may result in a decrease in film adhesion in dry inks such as urethane, which exhibit adhesion through intermolecular forces.

The ratio X/Y of the emission intensity of the emission peak X to the emission intensity of the reference peak Y
A preferred embodiment of the laminate of the present invention is a laminate in which the ratio X/Y of the emission intensity X of the emission peak to the emission intensity Y of the reference peak measured under the following measurement conditions from the coating layer side is 5 or more and 300 or less.

<Measurement conditions>
The coating layer side of the laminate was brought into contact with a 1× ^10-4 mol/L THF solution of 4-Nitro-7-piperazino-2,1,3-benzoxadiazole at 60° C. for 30 minutes, and the laminate was then immersed and washed twice in THF. Thereafter, a 15 mm×15 mm piece was cut out and the emission spectrum was measured by exciting at 470 nm, and the peak intensity of the emission maximum observed at 520 to 550 nm was calculated.

<Base Peak>
A 1×10 ⁻⁵ mol/L THF solution of 4-Nitro-7-piperazino-2,1,3-benzoxadiazole was measured in a quartz glass cell with an optical path length of 10 mm in the same manner as for the laminate.

The (meth)acryloyl group is an α-β unsaturated carbonyl compound, and therefore can be converted to a 3-aminopropionate structure by 1,4 conjugate addition of highly nucleophilic primary or secondary amines (Michael addition reaction). By using this reaction to selectively introduce 4-Nitro-7-piperazino-2,1,3-benzoxadiazole, a fluorescent dye with a secondary amino group, into the (meth)acryloyl group, it is possible to quantify the (meth)acryloyl group in the film. The fluorescent dye has only one secondary amino group, so it reacts with the (meth)acryloyl group at an equivalent ratio of 1:1. In addition, since it is an aliphatic amine with high nucleophilicity, the reaction proceeds even at room temperature without a catalyst. In addition, since it has absorption and fluorescence emission in the visible light region of 400 nm or more, it can be detected spectroscopically. In addition, since the contact time is short, the thickness of the coating layer does not affect the value of X very much. The detailed measurement method is determined by the method described in the examples.

The presence of a certain amount or more of (meth)acryloyl groups in the coating layer improves adhesion to ink. In the present invention, attention is focused on X/Y as an index of the amount of (meth)acryloyl groups in the coating layer. If X/Y is less than 5, adhesion between the ink and the film laminate may decrease. From the viewpoint of adhesion, X/Y is more preferably 18 or more. On the other hand, if X/Y exceeds 300, the increase in the amount of (meth)acryloyl groups in the coating layer may expand the voids inside the layer, decreasing the gas barrier properties. In addition, adhesion to dry inks such as urethane, which exhibit adhesion through intermolecular forces, may decrease. From the viewpoints of gas barrier properties and adhesion, X/Y is more preferably 100 or less.

The coating layer in the present invention preferably has a thickness of 200 nm or more and 600 nm or less, and more preferably 200 nm or more and 500 nm or less. By making the thickness 200 nm or more, the metal layer and/or inorganic compound layer can be coated without defects and the barrier properties can be improved. By making the thickness 600 nm or less, cracks due to thermal shrinkage during curing and insufficient curing can be prevented, which is preferable. The thickness of the coating layer will be determined by the method described in the examples.

In the present invention, the coating layer preferably has a ratio P1/P2 of peak intensities P1 and P2 detected by FT-IR-ATR measurement of 3.5 to 8.0, more preferably 4.0 to 6.5 (where P1 indicates the intensity of the maximum peak present at 1,050 to 1,080 cm ^-1 , and P2 indicates the intensity of the maximum peak present at 920 to 970 cm ^-1 . Note that peak intensity is the absorbance (unitless) at the peak position). The FT-IR-ATR method can capture the characteristics of the surface coating layer, where P1 indicates the reaction product Si-O-Si, and P2 indicates the amount of the reaction raw material Si-OH. Therefore, the ratio P1/P2 of peak intensities P1 and P2 increases as the polycondensation of metal alkoxide proceeds. When the polycondensation reaction of the metal alkoxide proceeds, the terminal OH is reduced to form a strong film, improving the barrier properties and improving the moist heat resistance when retorted as a packaging material. When P1/P2 is 3.5 or more, the terminal OH is reduced to form a strong film, and a layer excellent in barrier properties and moist heat resistance can be obtained. When P1/P2 is 8.0 or less, cracks and embrittlement due to shrinkage of the film can be suppressed, which is preferable. P1 and P2 are determined by the method described in the examples. In order to set the ratio P1/P2 of the peak intensities P1 and P2 detected by the FT-IR-ATR method to a preferred range, it is necessary to sufficiently proceed with the reaction of the metal alkoxide. Since the polycondensation of the metal alkoxide is a dehydration reaction, it can be proceeded by heating, but the polyolefin resin film used in the base film constituting the more preferable laminate of the present invention has a low heat resistance compared to conventional polyester resins, so there was a problem that it was difficult to sufficiently proceed with the reaction. As a result of extensive research, the inventors have succeeded in obtaining a film with suitable properties even in low-temperature processing by mixing a component that can form a network at low temperatures. They also discovered that the deterioration of barrier properties in post-processing can be suppressed by adjusting P1/P2 to 3.5 or more and 8.0 or less.

When the laminate of the present invention is used as a packaging material, it is subjected to heat and pressure as it goes through printing and bag making processes. In this case, a coating that forms an appropriate network can function as a protective film, which is preferable. On the other hand, for example, if P1/P2 is less than 3.5, there is a lot of unreacted metal alkoxide, so the coating layer does not harden and is prone to scratches and deterioration of barrier properties, or, depending on the processing conditions, the unreacted metal alkoxide hardens and shrinks, causing barrier deterioration. On the other hand, if P1/P2 exceeds 8.0, the coating layer becomes embrittled, and cracks are likely to occur due to the pressure during lamination and the transport tension, causing barrier deterioration.

The coating layer in the present invention is preferably a layer that contains one or more segments selected from a segment derived from a vinyl alcohol resin, a segment derived from a polysaccharide, and a segment derived from an acrylic polyol resin, as well as a segment having an Si-O bond, and also contains a metal element M.

The segment derived from a vinyl alcohol resin, the segment derived from a polysaccharide, and the segment derived from an acrylic polyol resin are the water-soluble resins described above, and the segment having a Si—O bond is at least one selected from the group consisting of a silicon alkoxide represented by Si(OR) ₄ , a hydrolysate of a silicon alkoxide, and a polycondensate of a hydrolysate of a silicon alkoxide, among the metal alkoxides described above.

The metal element M contained in the coating layer excludes silicon Si. The inclusion of the metal element M in the coating layer makes it possible to make the coating layer dense. It is believed that the reason the inclusion of the metal element M in the coating layer makes it dense is that the compound containing the metal element M penetrates moderately into the repetition of Si-O bonds, creating a moderate degree of freedom in the bonds and making it possible to suppress the occurrence of very fine structural defects and cracks compared to repetition of only Si-O bonds.

The compound containing the metal element M is preferably a complex (chelate) or alcoholate of at least one metal element selected from at least one metal element selected from metals and semimetals excluding silicon, and may contain two types of metal elements. The metal element M preferably contains a metal element having an empty orbital, and the sum of the elemental ratios of the metal elements having an empty orbital is preferably 80 atom% or more in the total of 100 atom% of the metal elements M (excluding silicon). The metal element M preferably contains at least one metal element selected from aluminum, titanium, and zirconium, and more preferably the sum of the elemental ratios of aluminum, titanium, and zirconium is 80 atom% or more in the total of 100 atom% of the metal elements M (excluding silicon), and further preferably consists of at least one selected from aluminum, titanium, and zirconium, and particularly preferably the sum of the elemental ratios of titanium and zirconium is 80 atom% or more in the total of 100 atom% of the metal elements M (excluding Si), and most preferably consists of zirconium and/or titanium.

Examples of chelates or alcoholates containing aluminum element include aluminum tris(acetylacetonate), aluminum monoacetylacetonate bis(ethylacetoacetate), aluminum di-n-butoxide monoethylacetoacetate, aluminum di-iso-propoxide monomethylacetoacetate, aluminum tris(ethylacetoacetate), etc.

Examples of chelates or alcoholates containing titanium element include titanium orthoesters such as tetra-normal-butyl titanate, tetraisopropyl titanate, butyl titanate dimer, tetra(2-ethylhexyl) titanate, and tetramethyl titanate; and titanium chelates such as titanium acetylacetonate, titanium tetraacetylacetonate, polytitanium acetylacetonate, titanium octylene glycolate, titanium lactate, titanium triethanolamine, and titanium ethylacetoacetate.

Examples of chelates or alcoholates containing zirconium element include zirconium acetate, zirconium normal propylate, zirconium normal butylate, zirconium tetraacetylacetonate, zirconium monoacetylacetonate, zirconium bisacetylacetonate, etc.

In order to ensure coating liquid stability when these are added, it is preferable to mix them as chelates, such as aluminum tris(ethylacetoacetate), aluminum monoacetylacetonate bis(ethylacetoacetate), titanium lactate, titanium diethanolaminate, diisopropoxytitanium bis(triethanolaminate), zirconium lactate, etc. Among these, titanium chelates are preferred because they provide stability even with small ligands, since reducing the amount of ligand residue after the reaction can suppress an increase in free volume derived from the ligands.

The polycondensation product of silicon alkoxide that forms the coating layer needs to undergo a sufficient reaction in order to provide a barrier. Therefore, by mixing a highly reactive metal chelate, it is possible to achieve both appropriate reactivity and stability of the coating liquid.

The coating layer of the present invention preferably has a ratio m/s of the peak intensity m of the fragment ion derived from the metal element M to the peak intensity s of the fragment ion derived from the segment having a Si-O bond, measured at the center of the coating layer thickness using a time-of-flight secondary ion mass spectrometer (TOF-SIMS), of 0.05 or more and 10.00 or less.

The ratio m/s of the peak intensity m of the fragment ion derived from the metal element M to the peak intensity s of the fragment ion derived from the segment having a Si-O bond, as measured by a time-of-flight secondary ion mass spectrometer (TOF-SIMS), is determined by the following method.

<Apparatus and measurement conditions>
Time-of-flight secondary ion mass spectrometer TOF-SIMS5 manufactured by ION TOF
<Measurement conditions>
Primary ion species: Bi ⁺ (2 pA, 50 μs)
Acceleration voltage: 25 kV
Detected ion polarity: positive
Measurement range: 100 μm x 100 μm
Resolution: 128×128
Etching ion species: O ²⁺ (2 keV, 170 nA)
Etching area: 300 μm × 300 μm
Etching rate: 1 sec/cycle.

<Identifying the center of the coating layer>
The thickness of the coating layer is calculated by the thickness calculation method described in the examples, and half of the thickness is set as the central part. Next, the coating layer is analyzed while etching the thickness under the above measurement conditions. The analyzed sample is measured for the crater depth using a stylus-type step gauge (Dektak XTL, manufactured by BRUKER). The measured depth is converted using the average etching rate obtained by dividing the measured depth by the etching time, and the value of the central part is read. If there is no TOF-SIMS measurement data for the part that is exactly half the thickness, the TOF-SIMS measurement data of the measurement point closest to the part that is half the thickness is used. If there is not one measurement point closest to the part that is half the thickness, the average value of m/s calculated from the measurement data of each measurement point is set as the m/s of the part that is half the thickness.

<Pretreatment conditions>
If the coating layer is exposed on the outermost surface, no pretreatment is required, but if other layers are formed on the coating layer, those layers are removed before analyzing the coating layer. The method for removing the layers formed on the coating layer can be various ion etching methods such as argon ion beam etching or chemical treatment to remove the thickness of each layer. The thickness of each layer is determined by the method described in the examples.

<Analysis method>
The raw data is read using a time-of-flight secondary ion mass spectrometer TOF-SIMS5 manufactured by ION TOF and measurement software SURFACE LAB 7.1, and peaks assigned to various ions are read from the mass spectrum.

When m/s is 0.05 or more, a reaction promotion effect can be obtained even under low-temperature processing conditions, and the effect of the metal element M can make the coating layer dense, resulting in a layer with excellent barrier properties and moist heat resistance. m/s is more preferably 0.30 or more, and even more preferably 0.50 or more. When m/s is 0.05 or more, the amount of metal element M present in the coating layer can be made to be a certain amount or more, and since the metal element M acts as a catalyst, a reaction promotion effect can be obtained even under low-temperature processing conditions.

The metal element M is preferably one that easily forms a chelate. By forming a chelate, it is possible to ensure reactivity while simultaneously achieving stability in the coating liquid state. Examples of such metal elements include aluminum, titanium, and zirconium. When using a metal chelate containing the metal element M, it is preferable that it has an empty coordination site, which is the difference between the valence and the coordination number. In other words, the metal chelate functions as a Lewis acid. The empty coordination site is electronically unstable and is easily attacked, improving reactivity and providing a reaction promotion effect at a lower temperature. In addition, a metal chelate containing the metal element M can bond multiple silicon alkoxides, thereby promoting the reaction between adjacent silicon alkoxides. In other words, a highly reactive metal chelate lowers the activation energy of the reaction between silicon alkoxides, and can reduce the thermal energy required to promote polycondensation, thereby providing a reaction promotion effect at a lower temperature.

Laminate The laminate of the present invention preferably uses a polyolefin-based resin film as a substrate so that the packaging material can be recovered and recycled. The polyolefin-based resin film has a lower glass transition temperature than conventional polyester-based resins and polyamide-based resins. Therefore, even during storage in a roll, the film is likely to shrink and become tightly wound due to changes in the surrounding temperature. At that time, the coating layer is strongly pressed against the back surface of the film outside the roll, which causes a problem that the coating layer is more likely to deteriorate than conventional resin substrates.

After extensive research into this issue, it was found that even when tight rolling occurs with polyolefin resin films, barrier degradation can be suppressed by setting m/s to 0.05 or more and 10.00 or less. Setting m/s to 0.05 or more provides a reaction promotion effect even under low-temperature processing conditions, making low-temperature processing possible and suppressing stress on the film due to shrinkage of the coating layer caused by additional curing, while setting m/s to 10.00 or less makes it possible to control the progress of excessive reaction, suppressing embrittlement of the coating layer and suppressing barrier degradation when the film is pressed down by tight rolling.

Furthermore, after thorough investigation into this issue, it was found that barrier degradation can be suppressed by setting P1/P2 to 3.5 or more and 8.0 or less, even when tight rolling occurs with polyolefin resin film. Setting P1/P2 to 3.5 or more can suppress the stress placed on the film due to shrinkage of the coating layer caused by additional curing, while setting it to 8.0 or less can suppress embrittlement of the coating layer and suppress barrier degradation when the film is pressed down by tight rolling.

The laminate of the present invention preferably has a water vapor transmission rate of 1.0 g/m ² /day or less, more preferably 0.5 g/m ² /day or less. Also, the oxygen transmission rate is preferably 1.0 cc/m ² /day or less, more preferably 0.3 cc/m ² /day or less. The smaller the water vapor transmission rate and oxygen transmission rate, the more preferable, and the lower limit is not particularly limited, but the water vapor transmission rate is substantially 0.01 g/m ² /day and the oxygen transmission rate is 0.01 cc/m ² /day. By making the water vapor transmission rate 1.0 g/m ² /day or less and the oxygen transmission rate 1.0 cc/m ² /day or less, it is preferable that the deterioration due to moisture absorption and oxidation of the contents when made into a package can be prevented. The water vapor transmission rate and the oxygen transmission rate are measured by the method described in the examples.

The laminate of the present invention can be obtained by forming a metal layer and/or an inorganic compound layer on at least one surface of a substrate film, and then laminating a coating layer. The metal layer and/or the inorganic compound layer can be formed by using known methods such as vacuum deposition, sputtering, ion plating, and plasma vapor phase growth, but the deposition method can be used preferably because it can form a film at high speed with good productivity. The deposition method of the vacuum deposition method includes, but is not limited to, electron beam (EB) deposition, resistance heating, and induction heating. In addition, when forming a metal layer and/or an inorganic compound layer on a long resin film roll body, it is preferable to cool the main roll of the deposition in order to prevent the film from being damaged by heat, and the temperature is preferably 20° C. or less, more preferably 0° C. or less. As a method for obtaining a metal layer, an example of deposition using a target metal as a raw material can be mentioned. As a method for obtaining an inorganic compound layer, in addition to deposition using a compound of a target composition as a raw material, a method of using a metal as a raw material and introducing a reaction gas into the deposited metal vapor to obtain an inorganic compound can be exemplified. For example, when an aluminum oxide layer is obtained, aluminum is used as a deposition material, and a gas containing oxygen is introduced into the evaporated aluminum vapor to form an inorganic oxide layer on the film. The gas introduced may contain a gas having a composition that reacts with the evaporated metal and is incorporated into the layer, and may contain an inert gas or the like for controlling the film quality. The surface of the resin film on which the metal layer and/or inorganic compound layer is formed may be subjected to a surface modification treatment in order to improve interlayer adhesion. The surface modification treatment may be in-line or off-line, and the modification treatment method is not particularly limited, but examples thereof include known methods such as corona treatment, plasma treatment, ion beam treatment, and flame treatment. These surface modification treatments may be performed in air, or in an atmosphere of various gases such as argon, nitrogen, oxygen, carbon dioxide, hydrogen, ammonia, and hydrocarbons (C _n H _2n+2 , where n is an integer of 1 to 4), or a mixture of these gases. The gas used for the surface modification treatment can be selected based on the ease of discharge, the energy of the active species obtained, and the type of functional group to be introduced. However, it is preferable for the gas to contain carbon dioxide gas or oxygen gas for introducing functional groups, or argon or nitrogen gas, which are easy to stably discharge.

The laminate of the present invention is preferably manufactured by a manufacturing method including a step of applying a coating agent containing a hydrolyzate of a water-soluble resin and a metal alkoxide and/or a polycondensate thereof, and a silane coupling agent having a (meth)acryloyl group, to the surface of the laminate having a metal layer and/or an inorganic compound layer on at least one surface of a base film, and a drying step. By adopting this embodiment, when a printing layer is formed on the laminate, it is possible to obtain a laminate that exhibits high adhesion regardless of the type of ink and has good barrier properties.

Another preferred embodiment of the laminate of the present invention is preferably produced by a production method including a step of applying a coating agent containing a water-soluble resin, a hydrolyzate of a metal alkoxide and/or a polycondensate thereof, and a silane coupling agent having a (meth)acryloyl group to the surface of the metal layer and/or inorganic compound layer of a laminate having a metal layer and/or an inorganic compound layer on at least one surface of a polyolefin resin film, and a drying step. Also, it is preferable that the laminate is obtained by a production method of a laminate including a step of applying a coating agent containing one or more resins selected from silicon alkoxide, a hydrolyzate of silicon alkoxide, and a polycondensate of a hydrolyzate of silicon alkoxide, one or more resins selected from vinyl alcohol resins, polysaccharides, and acrylic polyol resins, a silane coupling agent having a (meth)acryloyl group, and a compound containing a metal element M to the surface of the metal layer and/or inorganic compound layer of a laminate having a metal layer and/or an inorganic compound layer on at least one surface of a polyolefin resin film, and a drying step. By adopting this embodiment, when a printed layer is formed on the laminate, a laminate exhibiting high adhesion and having good barrier properties can be obtained regardless of the type of ink. In addition, a laminate having high water vapor barrier properties and oxygen barrier properties can be obtained while suppressing the environmental load during production. In particular, by adopting this embodiment, the laminate can be sufficiently cured even at low temperatures, and can be sufficiently cured even at high temperatures in a short time, which is preferable because it reduces the environmental load during production. That is, a preferred embodiment of the method for producing a laminate of the present invention is a method for producing a laminate including a step of applying a coating agent containing a water-soluble resin, a hydrolyzate of a metal alkoxide and/or a polycondensate thereof, and a silane coupling agent having a (meth)acryloyl group to the surface having the metal layer and/or the inorganic compound layer of a laminate having a metal layer and/or an inorganic compound layer on at least one surface of a base film, and a step of drying. A more preferred embodiment is one in which the substrate film is a polyolefin resin film, and an even more preferred embodiment is one in which the coating agent is a coating agent containing at least one selected from silicon alkoxides, hydrolysates of silicon alkoxides, and polycondensates of hydrolysates of silicon alkoxides, at least one resin selected from vinyl alcohol resins, polysaccharides, and acrylic polyol resins, a silane coupling agent having a (meth)acryloyl group, and a compound containing a metal element M.

In addition, from the viewpoint of adhesion and gas barrier properties, it is preferable that the coating agent is obtained by mixing coating agent 1 containing a water-soluble resin and a hydrolysate and/or polycondensate of a metal alkoxide with coating agent 2 containing a hydrolysate and/or polycondensate of a silane coupling agent having a (meth)acryloyl group. By adopting this embodiment, a particularly large number of (meth)acryloyl groups can be introduced onto the surface of the coating layer. In addition, by adopting this embodiment, it is easy to form a laminate in which the coating layer has 0.25 mol % or more and 1.25 mol % or less of (meth)acryloyl groups relative to the total molar amount of metal elements contained in the coating layer, while the ratio X/Y is 5 or more and 300 or less.

The coating method is not particularly limited, and known methods can be used, such as direct gravure, reverse gravure, microgravure, rod coating, bar coating, die coating, spray coating, etc. The drying temperature after coating is preferably 70°C or higher and 150°C or lower, and more preferably 90°C or higher and 130°C or lower. The drying temperature refers to the maximum temperature reached on the film surface. By setting the temperature at 70°C or higher, the solvent can be removed to form a layer, and by setting the temperature at 150°C or lower, the thermal shrinkage and deformation of the base film can be suppressed. After coating and drying, the laminate of the present invention may be further heat-treated to promote the polycondensation reaction of silicon alkoxide to improve the barrier properties. The heat treatment temperature is preferably 30°C or higher and 100°C or lower, and more preferably 40°C or higher and 80°C or lower. The heat treatment time is preferably 1 day or higher and 14 days or lower, and more preferably 3 days or higher and 7 days or lower. By setting the heat treatment temperature at 30°C or higher, crosslinking of the coating layer can be promoted to improve the barrier properties, and by setting the temperature at 100°C or lower, curling and shrinkage of the film due to heat treatment can be suppressed. Note that the heat treatment temperature refers to the atmospheric temperature.

The laminate of the present invention is preferably used for packaging material applications. For use in packaging material applications, it may be laminated with another resin film for printing or other purposes, a heat seal layer for bag making, or to improve rigidity. In addition, in order to improve recyclability, the base film, heat seal layer, and resin film for improving rigidity are preferably polyolefin-based resins.

The laminate of the present invention is preferably used for printing with electron beam curable ink. By including the laminate in printing with electron beam curable ink, adhesion with the printed layer is improved and good barrier properties are obtained, so that it is preferable because the deterioration of the contents can be suppressed while the environmental load during the production of the printed layer can be reduced by using electron beam curable ink.

The present invention will be described below based on examples. Note that the present invention is not limited to these examples, and these examples can be modified or changed based on the spirit of the present invention, and are not excluded from the scope of the invention.

[Evaluation method]
(1) Thickness of the Base Film The thickness of ten randomly selected points was measured in an atmosphere of 23° C. and 65% RH using an electronic micrometer (K-312A type) manufactured by Anritsu Corp. The arithmetic mean value of the thicknesses at the ten points was taken as the thickness of the base film (unit: μm).

(2) Arithmetic mean height Sa of the base film
The measurements were made using a scanning white light interference microscope, Vertscan VS1540, manufactured by Hitachi High-Tech Science Corporation, which is a three-dimensional non-contact surface shape measuring instrument. In the analysis, the waviness components of the photographed image were removed using polynomial quartic approximation surface correction using the attached analysis software, and then the image was processed using a median (3 x 3) filter, followed by an interpolation process (a process in which pixels for which height data could not be obtained are supplemented with height data calculated from surrounding pixels). The measurement conditions were as follows.
Measurement conditions: Objective lens 10x
1x telescope tube
Zoom lens x 1
Wavelength filter 530nm white
Measurement mode: Wave
Measurement software: VS-Measure Version 10.0.4.0
・Analysis software: VS-Viewer Version 10.0.3.0
-Measurement area: 0.561 x 0.561 mm ² .

(3) Thickness of the metal layer and/or inorganic compound layer The thickness was measured by cross-sectional observation using a transmission electron microscope (TEM). Using a microsampling system FB-2000A manufactured by Hitachi, Ltd., an observation sample was prepared by the FIB method (specifically, based on the method described in "Polymer Surface Processing Science" (by Akira Iwamori), pp. 118-119). Next, the cross-section of the observation sample was observed using a transmission electron microscope H-9000UHRII manufactured by Hitachi, Ltd., at an acceleration voltage of 300 kV, and the thickness of the metal layer and/or inorganic oxide layer was confirmed at any 10 points. The arithmetic average value of these values was taken as the thickness (unit: nm) of the metal layer and/or inorganic oxide layer.

(4) Thickness of the coating layer The laminate was cut in a direction perpendicular to the film surface with a microtome, and the cross section of the laminate was observed and measured with a scanning transmission electron microscope. The observation was performed using a STEM (scanning transmission electron microscope/H-9000UHRII) manufactured by Hitachi, Ltd., and images were taken at three points at a magnification of 100,000 times. The thickness of the coating layer was measured in the three images obtained, and the average value was taken as the thickness of the coating layer (unit: nm).

(5) Ratio X/Y of emission intensity X to emission intensity Y of the reference peak
The prepared laminate was cut to 40 mm x 40 mm, and the coating layer side was surface-contacted with a 1 x 10 ^-4 mol/L THF solution of 4-Nitro-7-piperazino-2,1,3-benzoxadiazole at 60 ° C. for 30 minutes. Next, the laminate was immersed and washed twice in THF, and then the four corners of the washed film piece were cut, cut into 15 mm x 15 mm pieces, and fixed to a quartz plate to obtain a measurement sample. The measurement sample was subjected to fluorescence measurement by a transmission method using a fluorescent phosphorescence spectrophotometer (manufactured by Horiba, FluoroMax-4P) with 470 nm excitation light, excitation light slit 2 nm, emission slit 2 nm, and a light receiving range of 500 to 700 nm. When a peak of emission intensity was observed at 520 to 550 nm, the peak intensity was calculated as the emission intensity X.

Furthermore, a 1× ¹⁰ mol/L THF solution of 4-Nitro-7-piperazino-2,1,3-benzoxadiazole was measured using a quartz glass cell with an optical path length of 10 mm. The peak of the emission intensity at 520 to 550 nm obtained by the measurement was calculated as the emission intensity Y of the reference peak, and the ratio X/Y of the emission intensity X to the emission intensity Y of the reference peak was calculated.

(6) Water vapor transmission rate According to the B method of JIS K 7129 (2008), a water vapor transmission rate measuring device ("PERMATRAN (registered trademark)" W3/31) manufactured by MOCON/Modern Controls was used to measure water vapor transmission rate at a temperature of 40°C and a humidity of 90% RH. The measurement was performed twice for two test pieces, and the average value of the four measured values was calculated to obtain the water vapor transmission rate.

(7) Oxygen permeability According to the isobaric method of JIS K 7126-2 (2006), oxygen permeability was measured using an oxygen permeability measuring device ("OXTRAN (registered trademark)" 2/20) manufactured by MOCON/Modern Controls, Inc., under conditions of a temperature of 23°C and a humidity of 90% RH. The measurement was performed twice for each of two test pieces, and the average value of the four measured values was calculated to be the oxygen permeability.

(8) Analysis by FT-IR-ATR method (P1/P2)
A 30 mm x 30 mm sample of the laminate was used to perform spectrum measurement using a Fourier transform infrared spectrophotometer FT/IR-6100 manufactured by JASCO Corporation, and predetermined peaks P1 and P2 were detected in the peak detection mode of the analysis software. P1/P2 was calculated from the obtained values of P1 and P2.

P1/P2 was calculated at three different positions, and the values at the three points were averaged to obtain P1/P2 for that sample.
Light source: High brightness ceramic light source Detector: TGS
Beam splitter: Ge/KBr
Measurement mode: ATR method (Ge prism, incident angle 45°)
Measurement wave number range: 4,000 cm ^-1 to 600 cm ^-1
・Resolution: 4cm ^-1
Number of accumulations: 32 Analysis: Peaks were detected using the spectrum analysis program Spectra Manager Version 2.

(9) The ratio m/s of the peak intensity m of a fragment ion derived from a metal element M to the peak intensity s of a fragment ion derived from a segment having a Si—O bond
Using a time-of-flight secondary ion mass spectrometer TOF-SIMS5 manufactured by ION TOF and measurement software SURFACE LAB 7.1 manufactured by the same company, the peak intensity m of the fragment ion derived from the metal element M and the peak intensity s of the fragment ion derived from the segment having a Si-O bond were measured by secondary ion mass spectrometry for the center part of the coating layer, and the peak intensity ratio m/s was calculated. The measurement conditions are as follows.

Primary ion species: Bi ⁺ (2 pA, 50 μs)
Acceleration voltage: 25 kV
Detected ion polarity: positive
Measurement range: 100 μm x 100 μm
・Resolution: :128×128
Etching ion species: O ²⁺ (2 keV, 170 nA)
Etching area: 300 μm × 300 μm
Etching rate: 1 sec/cycle.

(10) Peel Strength A solid print layer was formed on each of the laminates obtained in Examples 1 to 42 and Comparative Examples 1 to 9 using the following inks A and B.

[Ink A: Richcure WL EB Cyan (electron beam curable waterless offset ink manufactured by Naigai Ink Mfg. Co., Ltd.), contains photosensitive resin. Acrylic equivalent: 166 g/eq].

Electron beam curable ink A was transferred to various laminates. The transfer method involved spreading the ink using an RI tester. Then, using an electron beam irradiation device (EC250/30/90LS manufactured by Iwasaki Electric Co., Ltd.), the ink was cured by irradiating it with electron beams at an acceleration voltage of 110 kV and an exposure dose of 30 kGy to obtain solid prints.

[Ink B: "Rio Alpha (registered trademark)" S R39 indigo (manufactured by Toyo Ink Co., Ltd., solvent gravure ink for reverse printing), contains polyurethane resin].

Solvent ink B was transferred onto various laminates. A bar coater number 8 was used for the transfer method. Solid prints were then obtained by drying in an oven at 80°C for 1 minute.

Next, a mixed lamination adhesive (Mitsui Chemicals, Inc.'s "Takelac (registered trademark)" A626 / "Takenate (registered trademark)" A50) was applied to the solid print obtained in each case so that the coating amount was 3.0 g / m ² , and laminated with a 70 μm thick non-oriented polypropylene film (CPP) (Toray Film Processing Co., Ltd.'s ZK-207). Then, it was aged at 40 ° C for 3 days to obtain a laminate sample. The obtained laminate sample was cut into a strip shape with a width of 15 mm, and a peel test was performed using a Tensilon universal testing machine (Orientec Co., Ltd.'s RTG-1210), and the peel strength (unit: N / 15 mm) when peeled at 90 ° at 300 mm / min was measured. Each was measured twice, and the average value was calculated to evaluate the adhesion.

If the peel strength is less than 2.0 N/15 mm, the adhesion is insufficient; if it is between 2.0 N/15 mm and 3.0 N/15 mm, the adhesion is good; if it is between 3.0 N/15 mm and 4.0 N/15 mm, the adhesion is better; and if it is 4.0 N/15 mm or more, the adhesion is judged to be extremely good.

[Example 1]
(Formation of Metal Layer or Inorganic Compound Layer)
An aluminum oxide layer having a thickness of 12 nm was formed as an inorganic compound layer on one side of a 12 μm-thick biaxially stretched polyethylene terephthalate film (Lumirror (registered trademark) P60 manufactured by Toray Industries, Inc.) The aluminum oxide layer was deposited by a reactive deposition method in which aluminum is evaporated and then oxidized by introducing oxygen into the deposition section.

(Formation of coating layer)
As a water-soluble polymer, polyvinyl alcohol (hereinafter sometimes abbreviated as PVA, Poval 28-98 manufactured by Kuraray Co., Ltd.) was added to a solvent of water/isopropyl alcohol = 97/3 by mass ratio, and heated and stirred at 90 ° C. to obtain a water-soluble polymer solution with a solid content of 10 mass %. Next, a solution of 6.7 g of TEOS and 2.7 g of methanol was mixed and stirred while adding dropwise 10.6 g of 0.02N hydrochloric acid solution to obtain a TEOS hydrolyzed solution. Furthermore, a solution of 6.1 g of 3-acryloxypropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd.: KBM-5103) and 10.6 g of methanol was mixed and stirred while adding dropwise 2.4 g of 0.1N hydrochloric acid solution to obtain a (meth)acryloyl group-containing hydrolyzed solution.

The water-soluble polymer solution and the TEOS hydrolyzed solution were mixed so that the ratio of the PVA solid content of the water-soluble polymer solution to the _SiO2 equivalent mass of TEOS was PVA solid content/ _SiO2 equivalent mass=35/65. The (meth)acryloyl group-containing hydrolyzed solution was added to the resulting mixed solution so that the (meth)acryloyl group content was 1.12 mol% relative to the total molar amount of metal elements contained in the coating layer, and the coating solution was diluted with water so that the total solid content was 13 mass% to obtain a coating solution. The coating solution was applied onto the above-mentioned aluminum oxide layer and dried at 150°C for 1 minute to obtain a laminate.

[Example 2]
A laminate was obtained in the same manner as in Example 1, except that the coating layer was dried and then further heat-treated at 80° C. for one week.

[Example 3]
A laminate was obtained in the same manner as in Example 2, except that the (meth)acryloyl group-containing hydrolyzed liquid for the coating layer was added so that the (meth)acryloyl group was 0.17 mol % relative to the total molar amount of metal elements contained in the coating layer.

[Example 4]
A laminate was obtained in the same manner as in Example 2, except that the (meth)acryloyl group-containing hydrolyzed liquid for the coating layer was added so that the (meth)acryloyl group was 0.28 mol % relative to the total molar amount of metal elements contained in the coating layer.

[Example 5]
A laminate was obtained in the same manner as in Example 2, except that the (meth)acryloyl group-containing hydrolyzed liquid for the coating layer was added so that the (meth)acryloyl group was 0.34 mol % relative to the total molar amount of metal elements contained in the coating layer.

[Example 6]
A laminate was obtained in the same manner as in Example 2, except that the (meth)acryloyl group-containing hydrolyzed liquid for the coating layer was added so that the (meth)acryloyl group was 0.56 mol % relative to the total molar amount of metal elements contained in the coating layer.

[Example 7]
A laminate was obtained in the same manner as in Example 2, except that the (meth)acryloyl group-containing hydrolyzed liquid for the coating layer was added so that the (meth)acryloyl group was 0.79 mol % relative to the total molar amount of metal elements contained in the coating layer.

[Example 8]
A laminate was obtained in the same manner as in Example 2, except that the (meth)acryloyl group-containing hydrolyzed liquid for the coating layer was added so that the (meth)acryloyl group was 1.01 mol % relative to the total molar amount of metal elements contained in the coating layer.

[Example 9]
A laminate was obtained in the same manner as in Example 2, except that the water-soluble polymer in the coating layer was a modified polyvinyl alcohol ("Exceval (registered trademark)" RS-1717 manufactured by Kuraray Co., Ltd.) and the (meth)acryloyl group-containing hydrolyzed liquid was added so that the (meth)acryloyl group was 1.01 mol % relative to the total molar amount of metal elements contained in the coating layer.
[Example 10]
A laminate was obtained in the same manner as in Example 9, except that the (meth)acryloyl group-containing hydrolyzed liquid for the coating layer was added so that the (meth)acryloyl group was 1.12 mol % relative to the total molar amount of metal elements contained in the coating layer.

[Example 11]
A laminate was obtained in the same manner as in Example 2, except that the water-soluble polymer of the coating layer was modified polyvinyl alcohol (ZF-15 manufactured by Nippon Vinyl Acetate & Poval Co., Ltd.) and the (meth)acryloyl group-containing hydrolyzed liquid was added so that the (meth)acryloyl group was 1.01 mol % relative to the total molar amount of the metal elements contained in the coating layer.

[Example 12]
A laminate was obtained in the same manner as in Example 2, except that the water-soluble polymer in the coating layer was a modified polyvinyl alcohol ("Exceval (registered trademark)" HR-3010 manufactured by Kuraray Co., Ltd.) and the (meth)acryloyl group-containing hydrolyzed liquid was added so that the (meth)acryloyl group was 1.01 mol % relative to the total molar amount of metal elements contained in the coating layer.

[Example 13]
A laminate was obtained in the same manner as in Example 2, except that the water-soluble polymer of the coating layer was modified polyvinyl alcohol (DF-20 manufactured by Japan Vinyl Acetate & Poval Co., Ltd.) and the (meth)acryloyl group-containing hydrolyzed liquid was added so that the (meth)acryloyl group was 1.01 mol % relative to the total molar amount of the metal elements contained in the coating layer.

[Example 14]
A laminate was obtained in the same manner as in Example 2, except that the (meth)acryloyl group-containing hydrolyzed liquid for the coating layer was added so that the (meth)acryloyl group was 1.68 mol % relative to the total molar amount of metal elements contained in the coating layer.

[Example 15]
A laminate was obtained in the same manner as in Example 2, except that the (meth)acryloyl group-containing hydrolyzed liquid for the coating layer was added so that the (meth)acryloyl group was 5.59 mol % relative to the total molar amount of metal elements contained in the coating layer.

[Example 16]
(Formation of Metal Layer or Inorganic Compound Layer)
An aluminum oxide layer having a thickness of 12 nm was formed as an inorganic compound layer on one side of a 12 μm-thick biaxially stretched polyethylene terephthalate film (Lumirror (registered trademark) P60 manufactured by Toray Industries, Inc.) The aluminum oxide layer was deposited by a reactive deposition method in which aluminum is evaporated and then oxidized by introducing oxygen into the deposition section.
(Formation of coating layer)
As a water-soluble polymer, polyvinyl alcohol (Poval 28-98 manufactured by Kuraray Co., Ltd.) was added to a solvent of water/isopropyl alcohol = 97/3 by mass ratio, and heated and stirred at 90 ° C. to obtain a water-soluble polymer solution with a solid content of 10 mass %. Next, a solution of 6.4 g of TEOS, 0.3 g of 3-acryloxypropyltrimethoxysilane (KBM-5103 manufactured by Shin-Etsu Chemical Co., Ltd.), and 2.7 g of methanol was mixed with 10.6 g of 0.02 N hydrochloric acid solution while being added dropwise, to obtain a (meth)acryloyl group-containing TEOS hydrolyzed solution.

The water-soluble polymer solution was mixed with the (meth)acryloyl group-containing TEOS hydrolyzed solution so that the ratio of the PVA solid content of the water-soluble polymer solution to the _SiO2 -equivalent mass of TEOS was PVA solid content/ _SiO2 -equivalent mass = 35/65. The solution was diluted with water to a total solid content of 13 mass% to obtain a coating solution. The coating solution was applied onto the above-mentioned aluminum oxide layer, dried at 150°C for 1 minute, and then heat-treated at 80°C for 1 week to obtain a laminate.

[Example 17]
A laminate was obtained in the same manner as in Example 7, except that in preparing the coating solution for the coating layer, the ratio of the PVA solid content of the water-soluble polymer solution to the _SiO2 -equivalent mass of the TEOS hydrolyzed solution was set to PVA solid content/ _SiO2 -equivalent mass = 20/80.

[Example 18]
A laminate was obtained in the same manner as in Example 4, except that in preparing the coating solution for the coating layer, the ratio of the PVA solid content of the water-soluble polymer solution to the _SiO2 -equivalent mass of the TEOS hydrolyzed solution was set to PVA solid content/ _SiO2 -equivalent mass = 80/20.

[Example 19]
A laminate was obtained in the same manner as in Example 6, except that in preparing the coating solution for the coating layer, the ratio of the PVA solid content of the water-soluble polymer solution to the _SiO2 -equivalent mass of the TEOS hydrolyzed solution was set to PVA solid content/ _SiO2 -equivalent mass = 55/45.

[Example 20]
A laminate was obtained in the same manner as in Example 2, except that in preparing the coating solution for the coating layer, the ratio of the PVA solid content of the water-soluble polymer solution to the _SiO2 -equivalent mass of the TEOS hydrolyzed solution was set to PVA solid content/ _SiO2 -equivalent mass = 5/95.

[Examples 21 to 23]
A laminate was obtained in the same manner as in Example 8, except that the coating thickness of the coating layer was changed.

[Example 24]
A laminate was obtained in the same manner as in Example 6, except that in the preparation of the coating liquid for the coating layer, zirconium chelate ("Orgatix (registered trademark)" ZC-300, manufactured by Matsumoto Fine Chemical Co., Ltd.: zirconium lactate ammonium salt, solid content concentration 12 mass%) was further added in an amount of 2.98 mol % relative to the total molar amount of metal elements contained in the coating layer (excluding the (meth)acryloyl group-containing hydrolyzed liquid of the coating layer), and the coating liquid was applied onto the aluminum oxide layer, dried at 120°C for 1 minute, and then heat-treated at 80°C for 1 week.

[Example 25]
A laminate was obtained in the same manner as in Example 24, except that a biaxially oriented polypropylene film having a thickness of 12 μm (polypropylene film manufactured by Toray Industries, Inc., melting point 170° C., Sa 21 nm) was used in forming the metal layer or inorganic compound layer.

[Example 26]
A laminate was obtained in the same manner as in Example 24, except that a biaxially oriented polypropylene film having a thickness of 12 μm (polypropylene film manufactured by Toray Industries, Inc., melting point 170° C., Sa 21 nm) was used in the formation of the metal layer or inorganic compound layer, and a titanium chelate (TC-310 manufactured by Matsumoto Fine Chemical Co., Ltd.: titanium lactate, solid content concentration 44 mass%) was added in place of a zirconium chelate in the preparation of the coating liquid for the coating layer at 0.61 mol% relative to the total molar amount of the metal elements contained in the coating layer (excluding the (meth)acryloyl group-containing hydrolyzed liquid of the coating layer).

[Examples 27 to 35]
Laminates were obtained in the same manner as in Example 26, except that in the preparation of the coating solution for the coating layer, the (meth)acryloyl group-containing hydrolyzed liquid was added in amounts of 0.17 mol%, 0.28 mol%, 0.34 mol%, 0.56 mol%, 0.79 mol%, 1.01 mol%, 1.12 mol%, 1.68 mol%, and 5.59 mol% based on the total molar amount of the metal elements contained in the coating layer, and further, titanium chelate (TC-310 manufactured by Matsumoto Fine Chemical Co., Ltd.: titanium lactate, solid content concentration 44 mass%) was added in an amount of 1.81 mol% based on the total molar amount of the metal elements contained in the coating layer (excluding the (meth)acryloyl group-containing hydrolyzed liquid of the coating layer).

[Example 36]
A laminate was obtained in the same manner as in Example 26, except that in the preparation of the coating solution for the coating layer, titanium chelate (TC-310: titanium lactate manufactured by Matsumoto Fine Chemical Co., Ltd., solid content concentration 44 mass%) was added in an amount of 3.56 mol% based on the total molar amount of the metal elements contained in the coating layer (excluding the (meth)acryloyl group-containing hydrolyzed solution of the coating layer).

[Example 37]
In preparing the coating solution for the coating layer, a titanium chelate (TC-400: titanium triethanolamine, manufactured by Matsumoto Fine Chemical Co., Ltd., solid content concentration 79 mass%) was added in an amount of 8.15 mol% based on the total molar amount of the metal elements contained in the coating layer (excluding the (meth)acryloyl group-containing hydrolyzed solution of the coating layer), except that a laminate was obtained in the same manner as in Example 26.

[Examples 38 to 41]
In preparing the coating solution for the coating layer, a zirconium chelate (Orgatix ZC-300 manufactured by Matsumoto Fine Chemical Co., Ltd.: zirconium lactate ammonium salt, solid content concentration 12 mass%) was added in amounts of 0.20 mol%, 0.41 mol%, 17.7 mol%, and 19.7 mol% relative to the total molar amount of the metal elements contained in the coating layer (excluding the (meth)acryloyl group-containing hydrolyzed solution of the coating layer), except that a laminate was obtained in the same manner as in Example 26.

[Example 42]
A laminate was obtained in the same manner as in Example 25, except that an undercoat layer was formed on one side of the biaxially oriented polypropylene film and then an inorganic compound layer was formed thereon.

The undercoat layer was formed by the following procedure. Six parts by mass of the melamine compound "Amidair (registered trademark)" APM (manufactured by DIC Corporation) were added as a crosslinking agent to 100 parts by mass of "Hydran (registered trademark)" AP-201 (manufactured by DIC Corporation, solids concentration 23%), which is a polyester urethane-based water-dispersible resin, and one part by mass of "Catalyst" PTS (manufactured by DIC Corporation), a water-soluble acidic compound, was added as a crosslinking catalyst. Pure water was then added to adjust the overall solids concentration to 10%, to obtain a mixed coating. This mixed coating liquid was applied to one side of a biaxially oriented polypropylene film and dried at 110°C for 30 seconds to form an undercoat layer with a thickness of 700 nm.

[Comparative Example 1]
A laminate was obtained in the same manner as in Example 1, except that no covering layer was formed.

[Comparative Example 2]
A laminate was obtained in the same manner as in Example 3, except that the (meth)acryloyl group-containing hydrolyzed liquid was not added.

[Comparative Example 3]
A laminate was obtained in the same manner as in Example 3, except that the amount of the (meth)acryloyl group-containing hydrolyzed liquid added was such that the (meth)acryloyl group accounted for 18.72 mol % of the total molar amount of metal elements contained in the coating layer.

[Comparative Example 4]
A laminate was obtained in the same manner as in Example 3, except that an isocyanate group-containing hydrolyzed liquid (a hydrolyzed liquid in which 3-isocyanatepropyltriethoxysilane (X-12-1308ES, with an isocyanate protecting group, manufactured by Shin-Etsu Chemical Co., Ltd.) was used instead of 3-acryloxypropyltrimethoxysilane (KBM-5103, manufactured by Shin-Etsu Chemical Co., Ltd.) in the (meth)acryloyl group-containing hydrolyzed liquid in Example 1) was added in place of the (meth)acryloyl group-containing hydrolyzed liquid, such that the isocyanate group accounted for 1.12 mol % relative to the total molar amount of metal elements contained in the coating layer.

[Comparative Example 5]
A laminate was obtained in the same manner as in Example 3, except that a vinyl group-containing hydrolyzed liquid (a (meth)acryloyl group-containing hydrolyzed liquid in Example 1 using vinyltriethoxysilane (Shin-Etsu Chemical Co., Ltd.: KBE-1003) instead of 3-acryloxypropyltrimethoxysilane (Shin-Etsu Chemical Co., Ltd.: KBM-5103) in the (meth)acryloyl group-containing hydrolyzed liquid in Example 1) was added in place of the (meth)acryloyl group-containing hydrolyzed liquid, such that the vinyl group accounted for 1.12 mol % relative to the total molar amount of metal elements contained in the coating layer.

[Comparative Example 6]
A laminate was obtained in the same manner as in Example 2, except that a biaxially oriented polypropylene film was used as the base film and that the (meth)acryloyl group-containing hydrolyzed liquid was not added.

[Comparative Example 7]
A laminate was obtained in the same manner as in Example 3, except that a biaxially oriented polypropylene film was used as the base film, that the (meth)acryloyl group-containing hydrolyzed liquid was not added, and that after applying the coating liquid, the coating liquid was dried at 160° C. for 1 minute.

[Comparative Example 8]
A laminate was obtained in the same manner as in Example 3, except that an epoxy group-containing hydrolyzed liquid (a liquid in which 3-glycidoxypropyltriethoxysilane (KBE-403 manufactured by Shin-Etsu Chemical Co., Ltd.) was used instead of 3-acryloxypropyltrimethoxysilane (KBM-5103 manufactured by Shin-Etsu Chemical Co., Ltd.) in the (meth)acryloyl group-containing hydrolyzed liquid in Example 1) was added in place of the (meth)acryloyl group-containing hydrolyzed liquid, such that the epoxy group accounted for 1.12 mol % relative to the total molar amount of metal elements contained in the coating layer.

[Comparative Example 9]
A laminate was obtained in the same manner as in Example 3, except that a carboxyl group-containing hydrolyzed liquid (X-12-1135, manufactured by Shin-Etsu Chemical Co., Ltd., an aqueous silane coupling agent having a carboxyl group in an organic functional group, hydrolyzed) was added in place of the (meth)acryloyl group-containing hydrolyzed liquid so that the carboxyl group was 1.12 mol% relative to the total molar amount of the metal elements contained in the coating layer.

[Comparative Example 10]
(Formation of Metal Layer or Inorganic Compound Layer)
An aluminum oxide layer having a thickness of 12 nm was formed as an inorganic compound layer on one side of a 12 μm-thick biaxially stretched polyethylene terephthalate film (Lumirror (registered trademark) P60 manufactured by Toray Industries, Inc.) The aluminum oxide layer was deposited by a reactive deposition method in which aluminum is evaporated and then oxidized by introducing oxygen into the deposition section.

(Formation of coating layer)
As a water-soluble polymer, polyvinyl alcohol (hereinafter sometimes abbreviated as PVA, Poval 28-98 manufactured by Kuraray Co., Ltd.) was added to a solvent of water/isopropyl alcohol = 97/3 by mass ratio, and heated and stirred at 90 ° C. to obtain a water-soluble polymer solution with a solid content of 10 mass %. Next, the PVA of the water-soluble polymer solution, 3-acryloxypropyltrimethoxysilane (KBM-5103 manufactured by Shin-Etsu Chemical Co., Ltd.), and titanium chelate (TC-310 manufactured by Matsumoto Fine Chemical Co., Ltd.: titanium lactate, solid content concentration 44 mass %) were mixed so that the solid content ratio was 4/5/1, and diluted with water to a total solid content of 13 mass % to obtain a coating liquid. The coating liquid was applied onto the above-mentioned aluminum oxide layer and dried at 120 ° C. for 2 minutes to obtain a laminate.

In Comparative Example 2, the barrier properties were good, but because the coating layer did not contain a (meth)acryloyl group, adhesion to the printed layer using electron beam curable ink was not obtained.

In Comparative Example 3, the coating layer contains many (meth)acryloyl groups, so adhesion to the printed layer using electron beam curable ink is good, but the reduction in hydroxyl groups significantly deteriorates adhesion to gravure ink containing urethane resin, and the acryloyl groups, which are highly hydrophobic and have a large molecular weight, increase the voids in the coating layer, which is thought to have deteriorated the barrier properties.

In Comparative Examples 4 and 5, isocyanate groups and vinyl groups were used instead of (meth)acryloyl groups, and although the barrier properties were good, no adhesion to the printed layer using electron beam curable ink was obtained. It is believed that the isocyanate groups reacted with other components in the coating layer and were deactivated. Vinyl groups had a small molecular weight and were advantageous in terms of barrier properties, but compared with (meth)acryloyl groups, they generated fewer radicals and it is believed that sufficient adhesion was not obtained.

In Comparative Example 7, the drying temperature for the coating layer was high, and the coating layer was damaged by the shrinkage of the film, causing tiny cracks, etc., which is thought to have significantly deteriorated the oxygen barrier properties in particular.

In Comparative Examples 8 and 9, epoxy groups and carboxy groups were used instead of (meth)acryloyl groups, and although the barrier properties were good, adhesion to the printed layer using electron beam curable ink was not obtained. It is thought that the amount of radicals generated was small compared to (meth)acryloyl groups, and sufficient adhesion was not obtained. In addition, the highly hydrophobic (meth)acryloyl group tends to be unevenly distributed on the surface of the coating layer, so adhesion can be improved with a small amount, but hydrophilic functional groups tend to diffuse into the coating layer, and it is thought that it is difficult to improve adhesion with a small amount.

The above results show that the present invention can provide a laminate that has good adhesion to printed layers using various inks and also has good barrier properties. Furthermore, even in laminates using polyolefin resin substrates with low heat resistance, it is possible to provide laminates that have good adhesion to printed layers using various inks and also have good barrier properties.

1: Substrate film 2: Metal layer and/or inorganic oxide layer 3: Coating layer

Claims (13)

A laminate in which a metal layer and/or an inorganic compound layer, and a coating layer are laminated in this order on at least one surface of a base film, wherein the ratio X/Y of the emission intensity X of an emission peak to the emission intensity Y of a reference peak measured under the following measurement conditions from the coating layer side is 5 or more and 300 or less.
<Measurement conditions>
The coating layer side of the laminate was brought into contact with a 1× ^10-4 mol/L solution of 4-Nitro-7-piperazino-2,1,3-benzoxadiazole in THF (tetrahydrofuran) at 60°C for 30 minutes, and the laminate was then immersed and washed twice in THF. Thereafter, a piece was cut to a size of 15 mm×15 mm. In the emission spectrum measurement, the sample was excited at 470 nm, and the peak intensity of the emission maximum observed at 520 to 550 nm was calculated.
<Base Peak>
A 1×10 ⁻⁵ mol/L THF solution of 4-Nitro-7-piperazino-2,1,3-benzoxadiazole was measured in a quartz glass cell with an optical path length of 10 mm in the same manner as for the laminate. The laminate according to claim 1, wherein the coating layer contains a hydrolysate of a water-soluble resin and a metal alkoxide and/or a polycondensate thereof. The laminate according to claim 1 or 2, wherein the thickness of the coating layer is 200 nm or more and 600 nm or less. The laminate according to claim 1 or 2, wherein the metal layer and/or the inorganic compound layer contains aluminum. 3. The laminate according to claim 1, wherein the laminate has a water vapor permeability of 1.0 g/ ^m2 /day or less and an oxygen permeability of 1.0 cc/ ^m2 /day or less. The laminate according to claim 2, wherein the coating layer contains 0.25 mol% or more and 1.25 mol% or less of (meth)acryloyl groups relative to the total molar amount of metal elements contained in the coating layer. 3. The laminate according to claim 1, wherein a ratio X/Y of an emission intensity X of an emission peak to an emission intensity Y of a reference peak measured under the following measurement conditions from the coating layer side of the laminate is 18 or more and 100 or less.
<Measurement conditions>
The coating layer side of the laminate was brought into contact with a 1× ^10-4 mol/L THF solution of 4-Nitro-7-piperazino-2,1,3-benzoxadiazole at 60° C. for 30 minutes, and the laminate was then immersed and washed twice in THF. Thereafter, a 15 mm×15 mm piece was cut out and the emission spectrum was measured by exciting at 470 nm, and the peak intensity of the emission maximum observed at 520 to 550 nm was calculated.
<Base Peak>
A 1×10 ⁻⁵ mol/L THF solution of 4-Nitro-7-piperazino-2,1,3-benzoxadiazole was measured in a quartz glass cell with an optical path length of 10 mm in the same manner as for the laminate. The laminate according to claim 1 or 2, wherein the substrate film is a polyolefin-based resin film. The laminate according to claim 1 or 2, wherein the ratio P1/P2 of the following peak intensities P1 and P2 detected by measuring the coating layer by an FT-IR-ATR method (total reflection Fourier transform infrared spectroscopy) is 3.5 or more and 8.0 or less.
P1: Intensity of the maximum peak present at 1,050 to 1,080 cm ⁻¹ P2: Intensity of the maximum peak present at 920 to 970 cm ⁻¹ 3. The laminate according to claim 1 or 2, wherein the coating layer contains a metal element M in addition to a water-soluble resin and a hydrolysate of a metal alkoxide and/or a polycondensate thereof, and a ratio m/s of a peak intensity m of a fragment ion derived from the metal element M to a peak intensity s of a fragment ion derived from a segment having a Si—O bond, as measured by a time-of-flight secondary ion mass spectrometer (TOF-SIMS), is 0.05 or more and 10.00 or less.
<Measurement conditions>
Primary ion species: Bi ⁺ (2 pA, 50 μs)
Acceleration voltage: 25 kV
Detected ion polarity: positive
Measurement range: 100 μm x 100 μm
Resolution: 128×128
Etching ion species: O ²⁺ (2 keV, 170 nA)
Etching area: 300 μm × 300 μm
Etching rate: 1 sec/cycle The laminate according to claim 1 or 2, wherein the base film is a film derived from recycling. The laminate according to claim 1 or 2, which is used for packaging material applications. The laminate according to claim 1 or 2, which is used for printing with electron beam curable ink.

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