Laminate, method for producing laminate, packaging material, and packaging bag

Abstract

This method for producing a laminate 100 using a solvent-free adhesive comprises: a step for preparing a first film 10 that includes a chlorine-containing layer 15 and has a chlorine content of at least 0.0005 mass%; and a lamination step for adhering the first film 10 and a second film 20 using a urethane-based solvent-free adhesive, wherein, in the lamination step, the first film 10 and the second film 20 are laminated so that the chlorine-containing layer 15 comes into contact with a layer S'1 composed of the urethane-based solvent-free adhesive.

Description

Laminate, manufacturing method of laminate, packaging material, and packaging bag

[0001] The present disclosure relates to a laminate, a method for manufacturing a laminate, a packaging material, and a packaging bag.

[0002] As part of efforts to address environmental issues, packaging bags made of plastic films (e.g., flexible packaging bags) have become widespread. Flexible packaging bags often have a laminated structure in which two or more films are bonded together using an adhesive to improve required performance (e.g., strength, water resistance, moisture resistance, gas barrier properties against gases such as oxygen, heat resistance, etc.).

[0003] In recent years, from the viewpoint of reducing the environmental load, the use of solvent-free adhesives as adhesives for forming the above-mentioned laminated structures has been considered. However, when a laminate is produced using a solvent-free adhesive, there is a problem that poor appearance occurs due to the inclusion of air bubbles at the interface between the adhesive layer formed with the solvent-free adhesive and the adjacent layer.

[0004] In response to this, for example, Patent Document 1 proposes to solve the problem of poor appearance by devising a manufacturing method for a laminate film.

[0005] Japanese Patent Application Laid-Open No. 2003-236939

[0006] However, even with the method of Patent Document 1, there are cases where poor appearance occurs, and there is still room for improvement in the method of manufacturing a laminate using a solvent-free adhesive.

[0007] Therefore, an object of one aspect of the present disclosure is to suppress the occurrence of defects in appearance when a laminate is produced using a solvent-free adhesive. Another object of the present disclosure is to provide a laminate in which the above-mentioned defects in appearance are suppressed.

[0008] Some aspects of the present disclosure provide the following [1] to

[13] .

[0009] [1] A laminate comprising a first film, a second film, and a first adhesive layer that bonds the first film and the second film together, wherein the first adhesive layer is formed using a urethane-based solventless adhesive, the first film includes a chlorine-containing layer that forms a contact surface with the first adhesive layer, and the chlorine content in the first film is 0.0005% by mass or more.

[0010] [2] The chlorine-containing layer is ４ The laminate according to [1], containing chlorine derived from at least one chlorine-based material selected from the group consisting of:

[0011] [3] The laminate according to [2], wherein the chlorine-containing layer contains a reaction product of the chlorine-based material and an alkoxysilane.

[0012] [4] The laminate according to any one of [1] to [3], wherein the chlorine-containing layer contains a water-soluble polymer.

[0013] [5] The laminate according to any one of [1] to [4], wherein the first film further comprises an inorganic vapor deposition layer.

[0014] [6] The laminate according to [5], wherein the inorganic vapor deposition layer contains Al atoms or Si atoms.

[0015] [7] The laminate according to any one of [1] to [6], wherein the thickness of the first adhesive layer is 0.2 to 3.0 μm.

[0016] [8] The laminate according to any one of [1] to [7], wherein the second film includes a printed layer.

[0017] [9] The laminate according to any one of [1] to [8], further comprising a third film laminated via a second adhesive layer on the opposite side of the first adhesive layer of the first film or the second film.

[0018]

[10] The laminate according to any one of [1] to [9], which includes a sealant layer.

[0019]

[11] A packaging material comprising the laminate according to any one of [1] to

[10] .

[0020]

[12] A packaging bag made from the packaging material according to

[12] .

[0021]

[13] A method for producing a laminate using a solvent-free adhesive, comprising: a step of preparing a first film including a chlorine-containing layer and having a chlorine content of 0.0005% by mass or more; and a lamination step of bonding the first film and a second film together using a urethane-based solvent-free adhesive, wherein in the lamination step, the first film and the second film are laminated so that the chlorine-containing layer and a layer made of the urethane-based solvent-free adhesive are in contact with each other.

[0022] According to one aspect of the present disclosure, it is possible to suppress appearance defects that occur when a laminate is produced using a solvent-free adhesive. Also, according to another aspect of the present disclosure, it is possible to provide a laminate in which the above-mentioned appearance defects are suppressed.

[0023] Fig. 1 is a schematic cross-sectional view showing a method for producing a laminate according to one embodiment and a laminate obtained thereby, and Fig. 2 is a schematic cross-sectional view showing a method for producing a laminate according to another embodiment and a laminate obtained thereby.

[0024] In this specification, a numerical range indicated using "to" indicates a range that includes the numerical values ​​written before and after "to" as the minimum and maximum values, respectively. Furthermore, unless specifically stated otherwise, the units of the numerical values ​​written before and after "to" are the same. Furthermore, in the numerical ranges described in this specification, the upper or lower limit of the numerical range may be replaced with the values ​​shown in the examples. Furthermore, the upper and lower limit values ​​individually described can be combined arbitrarily. Furthermore, "A or B" may include either A or B, or may include both. Furthermore, in this specification, a "solvent-free adhesive" refers to an adhesive that does not substantially contain solvents (organic solvents and water) (the solvent content is 0.5 mass% or less).

[0025] Hereinafter, embodiments of the present invention will be described in detail, with reference to the drawings where necessary. However, the present invention is not limited to the following embodiments. In the drawings, the same or corresponding parts are designated by the same reference numerals, and duplicate explanations will be omitted. The dimensional ratios of the drawings are not limited to those shown in the drawings.

[0026] <Laminate and its manufacturing method> Figure 1 is a schematic cross-sectional view showing a laminate manufacturing method according to one embodiment and a laminate obtained thereby. The laminate manufacturing method according to one embodiment is a laminate manufacturing method using a solvent-free adhesive, and includes a step of preparing a first film 10 including a chlorine-containing layer 15 (see Figure 1(a)), and a lamination step of bonding the first film 10 and a second film 20 using a urethane-based solvent-free adhesive (see Figures 1(b) and 1(c)). In the lamination step, the first film 10 and the second film 20 are laminated so that the chlorine-containing layer 15 and a layer (first uncured layer) S'1 made of the urethane-based solvent-free adhesive are in contact with each other.

[0027] According to the above method, it is possible to suppress the appearance defects (particularly the appearance defects due to air bubbles) that occur when manufacturing a laminate using a solvent-free adhesive. Therefore, the laminate 100 shown in FIG. 1(c) obtained by the above method can be said to be a laminate in which the appearance defects are suppressed. Although the reason for such an effect is unclear, it is presumed that the chlorine in the chlorine-containing layer 15 slows down the progress of the curing reaction of the urethane-based solvent-free adhesive in the vicinity of the chlorine-containing layer 15, making it easier to form a smooth interface between the adhesive layer formed after curing of the urethane-based solvent-free adhesive and the second film, and making it difficult for microbubbles to form at the interface, thereby achieving the above effect.

[0028] First, the laminate 100 will be described below.

[0029] 1(c) includes a first film 10, a second film 20, and an adhesive layer S1 (first adhesive layer) that bonds the first film 10 and the second film 20. The thickness of the laminate 100 is, for example, 10 to 300 μm, and may be 30 to 160 μm.

[0030] (Adhesive Layer) The adhesive layer S1 is a layer formed using a urethane-based solventless adhesive, for example, a layer formed by curing a layer (first uncured layer) S'1 made of a urethane-based solventless adhesive. Therefore, the adhesive layer S1 includes, for example, a cured product of the urethane-based solventless adhesive. Note that the fact that the adhesive layer S1 is a layer formed using a solventless adhesive rather than a layer formed using a solvent-based adhesive can be confirmed, for example, by analysis using Fourier transform infrared spectroscopy.

[0031] The urethane-based solventless adhesive contains, for example, a polyol component such as polyester polyol, polyether polyol, or acrylic polyol, and a polyisocyanate component such as aromatic polyisocyanate or aliphatic polyisocyanate.

[0032] The polyisocyanate component may be a polyisocyanate monomer or a polyisocyanate derivative, and may contain one of these alone or two or more of these.

[0033] The polyisocyanate monomer is preferably a diisocyanate, which may be an aliphatic diisocyanate such as hexamethylene diisocyanate (HDI), an alicyclic diisocyanate such as isophorone diisocyanate (IPDI), an araliphatic diisocyanate such as xylylene diisocyanate (XDI), or an aromatic diisocyanate such as methylenebis(4,1-phenylene)diisocyanate (MDI).

[0034] The polyisocyanate derivative is a compound derived from the above polyisocyanate monomer. The polyisocyanate derivative may be a polymer (e.g., dimer, trimer, pentamer, etc.) of the polyisocyanate monomer, a biuret, an adduct, an allophanate, etc. The polyisocyanate derivative may also be an isocyanate-terminated prepolymer derived from the above polyisocyanate monomer.

[0035] The isocyanate-terminated prepolymer is a compound obtained, for example, by subjecting a polyisocyanate (a polyisocyanate monomer or a polyisocyanate derivative) to a urethanization reaction with the above-mentioned polyol component (particularly a diol) at an equivalent ratio (NCO / OH) of the isocyanate groups of the polyisocyanate to the hydroxyl groups of the polyol greater than 1. The isocyanate-terminated prepolymer may have a biuret structure formed by the reaction of an amine with an isocyanate, or may have a uretdione structure and / or an isocyanurate structure formed by the reaction of isocyanates themselves.

[0036] The urethane-based solventless adhesive may be a one-component curing adhesive in which a polyol component and a polyisocyanate component are premixed, or a two-component curing adhesive containing a base agent containing a polyol component and a curing agent containing a polyisocyanate component. The two-component curing adhesive is used by mixing the base agent and the curing agent. Either adhesive cures when heated or the like, with the components reacting (for example, the hydroxyl groups of the polyol component react with the isocyanate groups of the polyisocyanate component).

[0037] The equivalent ratio (NCO group / OH group molar ratio) of isocyanate groups (e.g., isocyanate groups in a polyisocyanate component) to hydroxyl groups (e.g., hydroxyl groups in a polyol component) in the urethane-based solventless adhesive can be, for example, 0.5 to 5.

[0038] From the viewpoint of increasing adhesive strength, the thickness of the adhesive layer S1 is preferably 0.2 μm or more. From the same viewpoint, the thickness of the adhesive layer S1 may be 0.8 μm or more or 1.6 μm or more. From the viewpoint of further suppressing appearance defects, the thickness of the adhesive layer S1 is preferably 3.0 μm or less. From the same viewpoint, the thickness of the adhesive layer S1 may be 2.5 μm or less, 2.0 μm or less, or 1.8 μm or less. From these viewpoints, the thickness of the adhesive layer S1 is preferably 0.2 to 3.0 μm.

[0039] (First Film) The first film 10 comprises a substrate 11 (first substrate), an inorganic vapor deposition layer 12, and a chlorine-containing layer 15, in this order. The first film 10 is, for example, a gas barrier film. The chlorine-containing layer 15 forms the contact surface with the adhesive layer S1 (i.e., the surface of the first film 10 that contacts the adhesive layer S1). It is sufficient that at least a portion of the contact surface with the adhesive layer S1 is formed by the chlorine-containing layer 15, but it is preferable that the entire contact surface with the adhesive layer S1 is formed by the chlorine-containing layer 15. The thickness of the first film 10 is, for example, 10 to 60 μm.

[0040] [Substrate] The substrate 11 is, for example, a resin film. Examples of resin materials constituting the resin film include polyesters such as polyethylene terephthalate, polyethylene naphthalate, and polybutylene terephthalate; polyamides such as nylon; polyolefins such as polypropylene, polyethylene, polymethylpentene, ethylene-propylene copolymer, and propylene-butene copolymer; polystyrene; polyimide; polyvinyl alcohol; polyvinyl chloride; and ethylene-vinyl alcohol copolymer. The resin film may be composed of only one type of resin or may contain two or more types of resin. The resin film may also be a composite film formed by laminating two or more films formed from the above resin materials. The resin film may contain materials other than resin (such as additives), but the resin content in the resin film is 98% by mass or more. The resin film may be a stretched resin film or a non-stretched resin film. The resin film may also be a stretched resin film laminated with a non-stretched resin film.

[0041] The substrate 11 is preferably a polypropylene film (a film containing 95% by mass or more of polypropylene) or a polyethylene terephthalate film (a film containing 95% by mass or more of polyethylene terephthalate). When these films are used, the substrate 11 has high adhesion to the adjacent layer (inorganic vapor deposition layer 12 in FIG. 1 ).

[0042] The surface of the substrate 11 (the surface on the chlorine-containing layer 15 side) may be subjected to various pretreatments such as corona treatment, plasma treatment, ozone treatment, etc. These treatments enhance the adhesion of the substrate 11 to the adjacent layer (inorganic vapor deposition layer 12 in FIG. 1 ).

[0043] The thickness of the substrate 11 can be changed as appropriate depending on the required characteristics of the application (for example, various resistances and processability required of the packaging material), and may be, for example, 10 to 60 μm.

[0044] [Inorganic Vapor Deposition Layer] The inorganic vapor deposition layer 12 is a layer formed by vapor deposition of an inorganic material such as a metal or an inorganic compound. Examples of metals include aluminum, magnesium, sodium, titanium, chromium, zinc, tin, gold, sodium, zirconium, and indium. Examples of inorganic compounds include aluminum oxide and silicon oxide (silica). These may be used alone or in combination of two or more. The inorganic vapor deposition layer 12 has barrier properties (gas barrier properties) against gases such as oxygen gas and water vapor gas, and functions as a gas barrier layer. When the inorganic vapor deposition layer 12 is a vapor deposition layer of a metal such as aluminum, the inorganic vapor deposition layer 12 can also function as a light-shielding layer.

[0045] From the viewpoint of exhibiting a more stable barrier property, the inorganic vapor deposition layer 12 preferably contains Al atoms or Si atoms, and is more preferably an aluminum vapor deposition layer, an aluminum oxide vapor deposition layer, or a silicon oxide vapor deposition layer.

[0046] When an adhesive layer formed using a solvent-free adhesive is adjacent to an inorganic vapor deposition layer, the aforementioned poor appearance due to trapped air bubbles is likely to occur. This is thought to be due to poor wettability and adhesion between the solvent-free adhesive and the inorganic vapor deposition layer. Specifically, when a solvent-free adhesive is applied, roughness occurs on the coated surface. When an inorganic vapor deposition layer is laminated onto such a rough coated surface, the roughness of the coated surface is not resolved, and air bubbles remain trapped due to the poor wettability and adhesion between the coating film and the inorganic vapor deposition layer, as well as the high cohesive strength of the coating film (adhesive) itself. Consequently, it is presumed that this poor appearance occurs. In contrast, in this embodiment, the chlorine-containing layer 15 is provided between the adhesive layer S1 and the inorganic vapor deposition layer 12, so the aforementioned poor appearance due to poor wettability and adhesion between the solvent-free adhesive and the inorganic vapor deposition layer 12 is unlikely to occur. Therefore, when the inorganic vapor deposition layer 12 is provided, the effect of suppressing the aforementioned poor appearance tends to be more pronounced.

[0047] The thickness of the inorganic vapor deposition layer 12 is preferably in the range of 0.01 to 0.1 μm.

[0048] [Chlorine-Containing Layer] The chlorine-containing layer 15 is a layer containing at least chlorine (Cl atoms). The chlorine content (chlorine content) may be, for example, 0.001% by mass or more, based on the total mass of the chlorine-containing layer 15. When the chlorine content is within the above range, poor appearance tends to be further suppressed. From the same perspective, the chlorine content may be 0.0350% by mass or more, or 0.700% by mass or more, based on the total mass of the chlorine-containing layer 15. The chlorine content may be 0.875% by mass or less, based on the total mass of the chlorine-containing layer 15. The chlorine content may be 0.0175 to 0.875% by mass, 0.035 to 0.875% by mass, or 0.700 to 0.875% by mass, based on the total mass of the chlorine-containing layer 15. The effect of the chlorine-containing layer in suppressing poor appearance is particularly pronounced when an isocyanate component with a fast curing rate is used as the isocyanate component. However, regardless of the type of isocyanate component, as long as the chlorine content is within the above range, there is a tendency for appearance defects to be further suppressed. In this specification, the chlorine content is the amount of chlorine measured by combustion ion chromatography, and specific measurement conditions are shown in the Examples.

[0049] Although the chlorine-containing layer is thin and it may not be easy to determine the chlorine content of the chlorine-containing layer, the same effect as described above tends to be obtained as long as the chlorine content (chlorine content) based on the total mass of the first film is 0.0005% by mass or more. That is, the chlorine content in the first film (chlorine content based on the total mass of the first film) may be 0.0005% by mass or more. From the viewpoint of further suppressing poor appearance, the chlorine content in the first film may be 0.0010% by mass or more or 0.0200% by mass or more. The chlorine content in the first film may be 0.0250% by mass or less. That is, the chlorine content in the first film may be 0.0005 to 0.0250% by mass, 0.0010 to 0.0250% by mass, or 0.0200 to 0.0250% by mass. The effect of the chlorine-containing layer in suppressing poor appearance is remarkable when an isocyanate component with a fast curing rate is used as the isocyanate component. However, regardless of the type of isocyanate component, as long as the chlorine content is within the above range, poor appearance tends to be further suppressed. The chlorine content is the amount of chlorine measured by combustion ion chromatography, and specific measurement conditions are shown in the examples.

[0050] The chlorine contained in the chlorine-containing layer 15 is preferably HCl (hydrogen chloride) and HClO ４ The chlorine is derived from at least one chlorine-based material selected from the group consisting of (perchloric acid).

[0051] The chlorine-containing layer 15 preferably contains a reaction product of the chlorine-based material and an alkoxysilane. This reaction product contains a hydrolyzate of the alkoxysilane in addition to chlorine derived from the chlorine-based material. The use of an alkoxysilane facilitates the film reaction, leading to the immobilization of chlorine. The hydrolyzate of the alkoxysilane may be a partial hydrolyzate in which some of the alkoxy groups of the alkoxysilane are hydrolyzed, or a complete hydrolyzate in which all of the alkoxy groups of the alkoxysilane are hydrolyzed. The reaction product may contain unreacted alkoxysilane or the chlorine-based material.

[0052] The alkoxysilane may be, for example, a tetraalkoxysilane. The four alkoxy groups of the tetraalkoxysilane may be the same or different. Examples of the alkoxy group include a methoxy group, an ethoxy group, and an ethoxymethoxy group. The tetraalkoxysilane is preferably tetramethoxysilane or tetraethoxysilane. Among them, tetraethoxysilane is easily stabilized in an aqueous solvent after hydrolysis. One type of tetraalkoxysilane may be used alone, or two or more types may be used in combination.

[0053] The alkoxysilane may be, for example, a silane coupling agent. The silane coupling agent has at least one reactive organic functional group and at least one alkoxy group. When a plurality of reactive organic functional groups and / or alkoxy groups are present, the plurality of groups may be the same.

[0054] Examples of reactive organic functional groups include vinyl groups, epoxy groups, amino groups, methacrylic groups, mercapto groups, isocyanate groups, etc. From the viewpoint of imparting excellent heat resistance to the packaging bag and making it easier to obtain stronger laminate strength even after high-temperature retort treatment, the reactive organic functional group is preferably an isocyanate group.

[0055] Examples of the alkoxy group include a methoxy group, an ethoxy group, an ethoxymethoxy group, etc. When the alkoxy group is a methoxy group, the hydrolysis rate of the silane coupling agent tends to be increased.

[0056] The silane coupling agent is, for example, XSiY ３ (X represents a reactive organic functional group, and a plurality of Ys each independently represent an alkoxy group.) The silane coupling agent may be a polymer formed by complexing the compound. When the silane coupling agent is a polymer of trimers or more, the heat resistance of the packaging bag is improved, and it becomes easier to obtain a stronger laminate strength even after high-temperature retort treatment.

[0057] Examples of the silane coupling agent include silane coupling agents having a vinyl group, such as vinyltrimethoxysilane and vinyltriethoxysilane; silane coupling agents having an epoxy group, such as 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldimethoxysilane and 3-glycidoxypropylethyldiethoxysilane; silane coupling agents having a mercapto group, such as 3-mercaptopropyltrimethoxysilane and 3-mercaptopropylmethyldimethoxysilane; silane coupling agents having an amino group, such as 3-aminopropyltrimethoxysilane and 3-aminopropyltriethoxysilane; and silane coupling agents having an isocyanate group, such as 3-isocyanatepropyltriethoxysilane and 1,3,5-tris(3-methoxysilylpropyl)isocyanurate. Among these, 1,3,5-tris(3-trialkoxysilylalkyl)isocyanurate has hydrophobicity due to the polarity of the nurate moiety, and can therefore impart water resistance to the chlorine-containing layer 15. The silane coupling agents may be used alone or in combination of two or more.

[0058] The content of alkoxysilane and its hydrolysate contained in the chlorine-containing layer 15 may be 40 to 75 mass %, or may be 45 to 70 mass %, or mass %, based on the total mass of the chlorine-containing layer 15. When the content of alkoxysilane and its hydrolysate is 75 mass % or less, cracking is less likely to occur, and when the content of alkoxysilane and its hydrolysate is 40 mass % or more, adhesion to the vapor-deposited film is more likely to be obtained.

[0059] The chlorine-containing layer 15 may contain a resin. For example, the chlorine-containing layer 15 may be a layer made of a resin composition containing a resin and a reaction product of the chlorine-based material and an alkoxysilane.

[0060] The resin preferably contains a water-soluble polymer from the viewpoint of imparting excellent gas barrier properties to the chlorine-containing layer 15. Examples of the water-soluble polymer include polyvinyl alcohol resin, modified products thereof, and polyacrylic acid. These may be used alone or in combination of two or more.

[0061] As the water-soluble polymer, it is preferable to use a polyvinyl alcohol resin or a modified product thereof from the viewpoint of obtaining better gas barrier properties. The polyvinyl alcohol resin or a modified product thereof is preferably used in combination with a silane coupling agent having a reactive organic functional group that reacts with a hydroxyl group. In this case, curing of the chlorine-containing layer 15 tends to obtain even better gas barrier properties. In addition, such a resin composition tends to have excellent flexibility after curing, and also contributes to suppressing the occurrence of cracks in the chlorine-containing layer 15 during processes such as lamination.

[0062] When the water-soluble polymer contains a polyvinyl alcohol resin or a modified product thereof, the saponification degree of the water-soluble polymer is not particularly limited, but from the viewpoint of improving the gas barrier property of the chlorine-containing layer 15, it is preferably 95% or more, and may be 99%.

[0063] The degree of polymerization of the water-soluble polymer is not particularly limited, but is preferably 300 or more, and more preferably 450 or more, from the viewpoint of improving the gas barrier property of the chlorine-containing layer 15. The degree of polymerization of the water-soluble polymer may be, for example, 300 to 2400, or 450 to 2400.

[0064] The content of the water-soluble polymer in the chlorine-containing layer 15 may be 15 to 60% by mass, 20 to 50% by mass, or 25 to 45% by mass, based on the total mass of the chlorine-containing layer 15. When the content of the water-soluble polymer is 60% by mass or less, adhesion to the vapor-deposited film is easily obtained, and when the content of the water-soluble polymer is 15% by mass or more, an appropriate network with the alkoxysilane is easily formed.

[0065] The ratio of the content of the water-soluble polymer to the content of the alkoxysilane and its hydrolysate contained in the chlorine-containing layer 15 (water-soluble polymer / alkoxysilane and its hydrolysate) is desirably 10% by mass or more, on a mass basis, from the viewpoint of preventing the layer from becoming too hard and making it easier to suppress the occurrence of cracks when the laminate is wound up.

[0066] The resin may consist solely of a water-soluble polymer, or may contain a resin other than the water-soluble polymer. The content of the water-soluble polymer may be, for example, 90% by mass or more, 95% by mass or more, or 100% by mass, based on the total amount of the resin.

[0067] The chlorine-containing layer 15 may contain known additives such as an isocyanate compound, a dispersant, a stabilizer, a viscosity adjuster, and a colorant, as needed, within the range that does not impair the effects of the present invention.

[0068] The thickness of the chlorine-containing layer 15 is preferably, for example, 0.1 μm or more. In this case, the gas barrier property after high retort treatment is improved compared to when the thickness of the chlorine-containing layer 15 is less than 0.1 μm. From the viewpoint of improving gas barrier property, the thickness of the chlorine-containing layer 15 is more preferably 0.15 μm or more, and particularly preferably 0.17 μm or more. On the other hand, from the viewpoint of improving flexibility, the thickness of the chlorine-containing layer 15 is preferably 1.5 μm or less. In this case, compared to when the thickness of the chlorine-containing layer 15 exceeds 1.5 μm, the laminate 100 is less likely to curl, making it easier to use as a gas barrier laminate for forming a packaging container.

[0069] (Second Film) The second film 20 includes a substrate 21 (second substrate) and a printed layer 22 provided on the substrate 21. In the second film 20, the printed layer 22 forms the contact surface with the adhesive layer S1 (i.e., the surface of the second film 20 that contacts the adhesive layer S1). The thickness of the second film is, for example, 3 to 150 μm, and may be 5 to 60 μm.

[0070] [Substrate] Examples of the substrate 21 are the same as the examples of the substrate 11 (first substrate) constituting the first film 10. The substrate 21 may be transparent so that a pattern formed by a printing layer can be displayed.

[0071] The thickness of the substrate 21 is, for example, 3 to 150 μm, and may be 5 to 60 μm.

[0072] [Printed Layer] The printed layer 22 is an ink layer formed with one or more inks. Examples of inks that can be used include general gravure ink, flexographic ink, offset ink, and digital printing ink. When the ink is an oil-based gravure ink, the ink may contain a binder resin such as a mixture of urethane resin and vinyl chloride-vinyl acetate copolymer resin. The ink contains a pigment and a binder resin, and may further contain various additives and a solvent (e.g., a volatile organic solvent). The ink may be an ink containing a colored pigment, known as a colored ink, or a colorless ink containing no colored pigment. Examples of inks that can be used include vegetable oil ink and biomass ink. The ink may also be a water-based ink.

[0073] The thickness of the printed layer 22 may be, for example, 0.05 to 8 μm.

[0074] Although not shown, the contact surface between the printed layer 22 and the adhesive layer S1 may have steps (unevenness). In conventional methods, defects in appearance are likely to occur at such steps, but in the method of the present embodiment, defects in appearance are unlikely to occur even when the second film 20 has such steps.

[0075] The laminate 100 described above is a laminate in which poor appearance is suppressed. For example, when observing the interface between the chlorine-containing layer 15 and the adhesive layer S1 of the laminate 100, the maximum diameter (maximum diameter) of bubbles observed within a 10 cm x 10 cm area is 0.8 mm or less. The maximum diameter (maximum diameter) of the bubbles is preferably 0.01 to 0.7 mm, and more preferably 0.01 to 0.6 mm. Note that a maximum diameter (maximum diameter) of bubbles observed within a 10 cm x 10 cm area of ​​0.8 mm or less means that there is no 10 cm x 10 cm area at the interface that contains bubbles with a diameter (maximum diameter) exceeding 0.8 mm.

[0076] The laminate 100 is suitable for use as a packaging material for forming a packaging bag (for example, a flexible bag) for packaging contents.

[0077] Next, each step in the method for manufacturing the laminate 100 will be described.

[0078] (Preparation Step) In the preparation step, first, a laminated film 13 is prepared, and the inorganic vapor deposition layer 12 of the laminated film 13 is coated with a chlorine-containing layer 15 to obtain a first film 10 (see FIG. 1(a)).

[0079] The laminated film 13 is a film including a substrate 11 (first substrate) and an inorganic vapor deposition layer 12 provided on the substrate 11. The laminated film 13 can be obtained by forming the inorganic vapor deposition layer 12 on the substrate 11 using a conventionally known method, such as a physical vapor deposition (PVD) method such as vacuum deposition, sputtering, or ion plating, or a chemical vapor deposition (CVD) method such as plasma enhanced chemical vapor deposition, thermal chemical vapor deposition, or photochemical vapor deposition. The laminated film 13 may be a known gas barrier film used for packaging bags, such as an aluminum vapor deposition polypropylene film called VM-CPP or an aluminum vapor deposition polyethylene terephthalate (PET) film called VM-PET.

[0080] The thickness of the laminated film 13 can be changed as appropriate depending on the required characteristics of the application (for example, various resistances and processability required of the packaging material), and may be, for example, 10 to 60 μm.

[0081] The chlorine-containing layer 15 is formed by adding each component of the material (e.g., HCl and HClO ４ The inorganic vapor deposition layer 12 can be formed by preparing a coating composition containing a reactive product of an alkoxysilane with at least one chlorine-based material selected from the group consisting of: (a reactive product of an alkoxysilane with at least one chlorine-based material selected from the group consisting of: a ...

[0082] The coating composition may be prepared by mixing the respective components that serve as materials. The coating composition may be prepared, for example, by mixing a liquid containing a reaction product between a chlorine-based material and an alkoxysilane with a resin, or by mixing a liquid containing a reaction product between a chlorine-based material and an alkoxysilane with a resin and an alkoxysilane (for example, the above-mentioned silane coupling agent). As the liquid containing the reaction product between a chlorine-based material and an alkoxysilane, the reaction liquid of a chlorine-based material and an alkoxysilane may be used as is.

[0083] The coating method may be a known coating method such as roll coating, gravure coating, spray coating, air knife coating, kiss coating, etc., and gravure coating is preferred from the viewpoints of productivity, uniformity of film thickness, etc. The amount of coating composition to be applied may be adjusted according to the desired thickness of the chlorine-containing layer 15 (for example, so that the basis weight after drying falls within the above-mentioned range).

[0084] The preparation step may include a step of obtaining a reaction product of the chlorine-based material and the alkoxysilane. This step includes, for example, mixing the chlorine-based material, the alkoxysilane, and an optional additive component. Examples of the additive component include methanol, ethanol, isopropyl alcohol, normal propyl alcohol, and butanol.

[0085] The chlorine-based material may be used by mixing with water. That is, an aqueous solution containing the chlorine-based material (e.g., hydrochloric acid) may be used in the preparation step. The concentration of the aqueous solution is not particularly limited, but may be 0.1 to 10 normal, or 0.5 to 5 normal.

[0086] The blending amount of the chlorine-based material may be 1 to 40 parts by mass, 5 to 30 parts by mass, or 10 to 25 parts by mass relative to 100 parts by mass of the alkoxysilane.

[0087] (Lamination Process) In the lamination process, first, a urethane-based solventless adhesive is applied to the surface of the second film 20 on the side of the printed layer 22, and then the first film 10 and the second film 20 are laminated together so that the layer (first uncured layer) S'1 made of the urethane-based solventless adhesive contacts the chlorine-containing layer 15 (see FIG. 1(b)). Next, the urethane-based solventless adhesive is cured to bond the first film 10 and the second film 20 together (see FIG. 1(c)). This results in the laminate 100.

[0088] The application of the adhesive and the lamination of the first film 10 and the second film 20 can be carried out using a known non-solvent laminator.

[0089] The application speed of the adhesive may be, for example, 100 to 400 m / min. The temperature of the adhesive during application may be, for example, 40 to 95°C. The viscosity of the adhesive during application (viscosity at the temperature during application) may be, for example, 10 to 1200 mPa·s. Here, the viscosity of the adhesive is the cone-plate viscosity in accordance with JIS K 5600-2-2:2014.

[0090] The lamination temperature of the first film 10 and the second film 20 may be, for example, 50 to 70° C. The lamination speed may be, for example, 100 to 400 m / min. The faster the lamination speed, the more likely it is that poor appearance will occur, but in the method of the present embodiment, a good appearance is likely to be obtained even if the lamination speed is 200 m / min or more (for example, 200 to 400 m / min).

[0091] The method for curing a urethane-based solvent-free adhesive varies depending on the type of adhesive. For example, if the urethane-based solvent-free adhesive is a thermosetting adhesive, the urethane-based solvent-free adhesive may be cured by heating the laminated body.

[0092] The method for producing a laminate according to one embodiment of the present disclosure and the laminate obtained by the production method have been described above, but the present disclosure is not limited to the above embodiment.

[0093] For example, the surface to which the urethane-based solvent-free adhesive is applied in the lamination step is not limited to the above, and the urethane-based solvent-free adhesive may be applied to the surface of the first film 10 on the chlorine-containing layer 15 side.

[0094] Also, for example, the first film 10 may not include the inorganic vapor deposition layer 12 .

[0095] Furthermore, for example, the first film 10 and the second film 20 may have other functional layers such as a concealing layer depending on the application. For example, the first film 10 may have an anchor coat layer between the substrate 11 and the inorganic vapor deposition layer 12.

[0096] The anchor coat layer is a layer that improves the adhesion between the substrate and the inorganic vapor deposition layer after heat sterilization and the gas barrier properties of the first film. The material constituting the anchor coat layer is not particularly limited as long as it can improve the adhesion between the substrate and the inorganic vapor deposition layer, but such materials include a reaction product of an organosilane or organometallic compound with a polyol component and a polyisocyanate component. In other words, the anchor coat layer can also be said to be a urethane-based adhesive layer.

[0097] The organosilane is, for example, a trifunctional organosilane or a hydrolyzate of a trifunctional organosilane. The organometallic compound is, for example, a metal alkoxide or a hydrolyzate of a metal alkoxide. The metal element contained in the organometallic compound is, for example, Al, Ti, Zr, etc. Each of the organosilane hydrolyzate and the metal alkoxide hydrolyzate may have at least one hydroxyl group.

[0098] The polyol component is preferably an acrylic polyol from the viewpoint of transparency. The polyisocyanate component functions mainly as a crosslinking agent or a curing agent. The polyol component and the polyisocyanate component may be a monomer or a polymer.

[0099] The thickness of the anchor coat layer is not particularly limited as long as it is capable of improving the adhesion between the substrate and the inorganic vapor deposition layer, but is preferably greater than 50 nm. In this case, the gas barrier property after high retort treatment is improved compared to when the anchor coat layer is 50 nm or less. The durability of the laminate can also be further improved. The thickness of the anchor coat layer is more preferably 70 nm or more, and even more preferably 80 nm or more. By increasing the thickness of the anchor coat layer, it is possible to further suppress the deterioration of the water vapor barrier property when an external force such as stretching is applied. The thickness of the anchor coat layer is preferably less than 300 nm. In this case, the durability of the laminate can be further improved and the gas barrier property after high retort treatment is enhanced compared to when the anchor coat layer is 300 nm or more. The thickness of the anchor coat layer is more preferably 200 nm or less.

[0100] In addition, for example, one or more other films other than the first film 10 and the second film 20 may be laminated to impart the mechanical strength, barrier properties, light resistance, openability, heat sealability, etc. required of the packaging bag.

[0101] As an example, as shown in FIG. 2 , a second adhesive may be applied to the surface of the third film 30, and then the laminate 100 and the third film 30 may be laminated together so that a layer (second uncured layer) S′2 made of the second adhesive contacts the substrate 11 of the first film 10, thereby obtaining the laminate 200. The laminate 200 thus obtained further includes, in addition to the laminate structure of the laminate 100, a second adhesive layer S2 (a layer containing a cured product of the second adhesive) and a third film 30 disposed on the first film 10 via the second adhesive layer S2 (i.e., on the opposite side of the first film 10 from the second film 20). The arrangement of the second adhesive layer S2 and the third film 30 is not limited to the above. For example, the third film 30 may be disposed on the second film 20 via the second adhesive layer S2 (i.e., on the opposite side of the second film 20 from the first film 10). Furthermore, the surface to which the second adhesive is applied is not limited to the above. For example, a layer (second uncured layer) S'2 made of the second adhesive may be formed by applying the second adhesive to the surface of the first film 10 or the surface of the second film 20 of the laminate 100.

[0102] The type of the other film, such as the third film, is not particularly limited. The other film may be, for example, a resin film exemplified for the first film. However, when the laminate is used as a packaging material, it is preferable that the laminate includes a sealant layer in the outermost layer (one of the two outermost layers). Therefore, in the laminate 200, it is preferable that the third film is a sealant layer. Examples of the sealant layer include a layer including a non-stretched resin film (non-stretched polyethylene film, non-stretched polypropylene film, etc.).

[0103] The adhesive used for laminating other films, such as the second adhesive, may be a solvent-free adhesive, or may be the above-mentioned urethane-based solvent-free adhesive.

[0104] The arrangement of the printed layer 22 in the second film 20 is not limited to the above. A film other than the second film 20 may include the printed layer 22, or the second film 20 may not include the printed layer 22. The laminate may also not include the printed layer 22. However, if the laminate includes a printed layer, the printed layer is usually provided on the inner surface of the laminate from the viewpoints of preventing ink scraping due to abrasion and preventing ink transfer when multiple laminates are stacked. From this viewpoint, the laminate may have a layered structure of, for example, outer layer / printed layer / adhesive layer / intermediate layer / adhesive layer / inner layer.

[0105] <Packaging Material> Another embodiment of the present disclosure is a packaging material (e.g., packaging film) including the laminate of the above embodiment. The packaging material includes, for example, a sealant layer as the outermost layer. A packaging material having such a configuration is suitably used to form a packaging bag (e.g., a flexible bag) for packaging contents. Specifically, for example, a packaging bag can be manufactured by bonding the sealant layers of a pair of packaging materials together and processing them into a bag. Furthermore, for example, a packaging bag can be manufactured by folding one piece of packaging material so that the surfaces of the sealant layers face each other and processing them into a bag. When the laminate of the above embodiment includes a sealant layer, the laminate can be used as a packaging material as is. When the laminate does not include a sealant layer, a film including a sealant layer (sealant film) can be attached to the laminate to form a packaging material.

[0106] <Packaging Bag> Another embodiment of the present disclosure is a packaging bag produced by manufacturing the packaging material of the above embodiment. Examples of the packaging bag include a flat pouch-shaped packaging bag and a self-standing packaging bag (standing pouch).

[0107] The flat pouch-shaped packaging bag may be, for example, a bag-shaped bag made by folding one sheet of packaging material (packaging material including a sealant layer) in half so that the sealant layers face each other, and then heat-sealing three sides, or may be a bag-shaped bag made by stacking two sheets of packaging material (packaging material including a sealant layer) on top of each other so that the sealant layers face each other, and then heat-sealing four sides.

[0108] The self-standing packaging bag may be, for example, a bag-shaped bag made by stacking three sheets of packaging material (packaging material including a sealant layer) with the sealant layers of the two sheets facing each other, and then inserting one sheet of packaging material (packaging material including a sealant layer) between the two sheets, folded in half with the sealant layer facing outward, and then heat-sealing the four sides.

[0109] The contents to be packaged in the packaging bag include liquids such as liquid seasonings, toiletries, soups, and liquid detergents, solids such as simmered dishes, and solid-liquid mixtures of liquids and solids such as curry.

[0110] The present disclosure will be described below based on examples and comparative examples, but the present disclosure is not limited to the following examples.

[0111] Preparation of Solventless Adhesive 1 (Polyester Polyol) 20 parts by weight of adipic acid and 20 parts by weight of polypropylene glycol were added to a 3 L, four-necked reactor equipped with a mechanical stirrer, nitrogen inlet, thermometer, and fractional distillation system, and the reactor was purged with nitrogen gas. The reactor was then heated to 210°C under a nitrogen atmosphere and maintained at this temperature until the temperature began to drop and water ceased to distill. The reaction mixture was then cooled to 170°C, and 100 g of diethylene glycol was added to the reactor. The reaction mixture was then slowly heated to 230°C over 4 hours and held at 230°C for 2 hours. The reactor was then evacuated from 600 mbar to 200 mbar over 8 hours while maintained at 230°C, followed by a 4-hour hold at 200 mbar and 230°C, yielding a polyetherester polyol.

[0112] (MDI-based polyisocyanate) 40 parts by mass of LOCTITE Liofol LA 6028 (manufactured by Henkel) and 60 parts by mass of CovestroDesmodur (registered trademark) 2460M (manufactured by Covestro AG, 50% to 60% 2,4'-MDI, ≧40% 4,4'-MDI, and <0.8% 2,2'-MDI) were mixed and slowly heated to 70° C. Heating was stopped when the NCO % became less than 16% by mass, to obtain an MDI-based polyisocyanate.

[0113] (Solvent-free adhesive 1) Solvent-free adhesive 1 was prepared by mixing 100 parts by mass of the polyester polyol and 100 parts by mass of an MDI-based polyisocyanate.

[0114] <Preparation of Solvent-Free Adhesive 2> "TSN-4864A" manufactured by Toyo-Morton Co., Ltd. was prepared as the polyester polyol, and a mixture was prepared by mixing HDI biuret (aliphatic polyisocyanate, product name: BASONAT HB100, manufactured by BASF) and IPDI nurate (aliphatic polyisocyanate, product name: VESTANAT T1890 / 100, manufactured by Evonik) in a mass ratio of 1:1. Solvent-free adhesive 2 was prepared by mixing 100 parts by mass of the polyester polyol and 100 parts by mass of the polyisocyanate.

[0115] <Preparation of Coating Liquid> (Coating Liquid 1) 7 parts by mass of tetraethoxysilane (trade name: KBE-04, manufactured by Shin-Etsu Chemical Co., Ltd.), 11 parts by mass of 0.02 N hydrochloric acid prepared by diluting 1 N hydrochloric acid (manufactured by Kanto Chemical Co., Inc.) with water, and 2.8 parts by mass of methanol were mixed, and the resulting mixture was stirred to hydrolyze the tetraethoxysilane. Next, 18 parts by mass of the resulting reaction liquid (a solution containing a hydrolyzate of tetraethoxysilane) was mixed with 22 parts by mass of a 5% by mass aqueous solution of polyvinyl alcohol (trade name: Kuraray Poval 60-90, manufactured by Kuraray Co., Ltd.) to prepare Coating Liquid 1.

[0116] (Coating Liquid 2) 14 parts by mass of tetraethoxysilane (trade name: KBE-04, manufactured by Shin-Etsu Chemical Co., Ltd.), 22.4 parts by mass of 0.02N hydrochloric acid prepared by diluting 1N hydrochloric acid (manufactured by Kanto Chemical Co., Ltd.) with water, and 5.6 parts by mass of methanol were mixed, and the resulting mixture was stirred to hydrolyze the tetraethoxysilane. Next, 37.4 parts by mass of the resulting reaction liquid (a solution containing the hydrolyzate of tetraethoxysilane) was mixed with 30 parts by mass of a 5% by mass aqueous solution of polyvinyl alcohol (trade name: Kuraray Poval 60-90, manufactured by Kuraray Co., Ltd.) and 0.5 parts by mass of the silane coupling agent 1,3,5-tris(3-methoxysilylpropyl)isocyanurate (manufactured by Shin-Etsu Chemical Co., Ltd., X-12-965P) to prepare coating liquid 2.

[0117] (Coating Liquid 3) A reaction liquid (a solution containing a hydrolyzate of tetraethoxysilane) was obtained in the same manner as in the preparation of Coating Liquid 1, and then the reaction liquid obtained was mixed with a 5 mass % aqueous solution of polyvinyl alcohol (trade name: Kuraray Poval 60-90, manufactured by Kuraray Co., Ltd.) in a mass ratio of 90:10 to prepare Coating Liquid 3.

[0118] (Coating Liquid 4) Coating liquid 4 was prepared by mixing tetraethoxysilane (trade name: KBE-04, manufactured by Shin-Etsu Chemical Co., Ltd.) and a 5 mass % aqueous solution of polyvinyl alcohol (trade name: Kuraray Poval 60-90, manufactured by Kuraray Co., Ltd.) in a mass ratio of 18:22.

[0119] <Preparation of anchor coat layer-forming composition> Acrylic polyol and tolylene diisocyanate were mixed so that the number of NCO groups in tolylene diisocyanate was equal to the number of OH groups in the acrylic polyol, and the mixture was diluted with ethyl acetate so that the solid content (acrylic polyol and tolylene diisocyanate) was 2 mass%. β-(3,4-epoxycyclohexyl)trimethoxysilane was further added to the diluted mixture in an amount of 5 parts by mass per 100 parts by mass of the total amount of acrylic polyol and tolylene diisocyanate, and these were mixed to prepare a composition for forming an anchor coat layer (anchor coating agent).

[0120] <Preparation of Barrier Film> (Barrier Film 1) The anchor coat layer-forming composition was coated on a PET film (product name: P60, manufactured by Toray Industries, Inc., thickness 12 μm) to form an anchor coat layer (thickness 0.05 μm). Next, an alumina (AlOx) vapor-deposited layer having a thickness of 10 nm was formed on the anchor coat layer by introducing oxygen while evaporating aluminum by EB (electron beam) vapor deposition. This gave barrier film 1.

[0121] (Barrier Film 2) The anchor coat layer-forming composition was coated on a PET film (product name: P60, manufactured by Toray Industries, Inc., thickness 12 μm) to form an anchor coat layer (thickness 0.05 μm). Next, a SiO material (product name: LUMILEAD SiO, manufactured by Canon Optron Inc.) was evaporated on the anchor coat layer by an EB (electron beam) deposition method to form a silica vapor deposition layer with a thickness of 25 nm. This gave barrier film 2.

[0122] Example 1 (Preparation of First Film) The above-mentioned barrier film 1 was prepared as a laminate film, and the above-mentioned coating liquid 1 was coated onto the surface of the alumina vapor-deposited layer of the barrier film 1 by gravure coating so that the thickness after drying would be 0.3 μm. The coating film formed by coating was then dried to form a chlorine-containing layer 1 with a thickness of 0.3 μm. This yielded a first film having a laminate structure of [barrier film 1 (PET film / anchor coat layer / alumina vapor-deposited layer) / chlorine-containing layer 1].

[0123] (Preparation of Laminate) The first film and nylon film 1 (product name: ONMB-RT, manufactured by Unitika Ltd., thickness 15 μm) were laminated using the solventless adhesive 1. The solventless adhesive 1 was applied to the surface of nylon film 1 using a roll coater at an adhesive temperature of 40°C and at a roll speed such that the thickness of the adhesive layer (solventless adhesive layer 1) formed after curing was 1.8 μm. Next, the solventless adhesive 1 was cured by aging treatment for 48 hours in an environment of 40°C. This resulted in a laminate having a laminate structure of [nylon film 1 / solventless adhesive layer 1 / chlorine-containing layer 1 / barrier film 1 (alumina vapor deposition layer / anchor coat layer / PET film)].

[0124] Example 2 A laminate having a laminated structure of [nylon film 1 / solvent-free adhesive layer 1 / chlorine-containing layer 2 / barrier film 1 (alumina vapor-deposited layer / anchor coat layer / PET film)] was obtained in the same manner as in Example 1, except that chlorine-containing layer 2 (thickness: 0.3 μm) was formed using coating liquid 2 instead of coating liquid 1, and the roll speed of solvent-free adhesive 1 was adjusted so that the thickness of the adhesive layer (solvent-free adhesive layer 1) formed after curing would be 1.6 μm.

[0125] Example 3 A laminate having a laminated structure of [nylon film 1 / solvent-free adhesive layer 1 / chlorine-containing layer 2 / barrier film 2 (silica vapor-deposited layer / anchor coat layer / PET film)] was obtained in the same manner as in Example 2, except that barrier film 2 was used instead of barrier film 1.

[0126] Example 4 A laminate having a laminate structure of [nylon film 1 / solvent-free adhesive layer 1 / chlorine-containing layer 1 / PET film] was obtained in the same manner as in Example 1, except that a PET film (product name: E5102, manufactured by Toyobo Co., Ltd., thickness 12 μm) was used instead of barrier film 1, and the roll speed of solvent-free adhesive 1 was adjusted so that the thickness of the adhesive layer (solvent-free adhesive layer 1) formed after curing would be 1.6 μm.

[0127] Example 5 (Preparation of First Film) A first film having a laminated structure of [barrier film 1 (PET film / anchor coat layer / alumina vapor-deposited layer) / chlorine-containing layer 2] was obtained in the same manner as in Example 1, except that the chlorine-containing layer 2 (thickness: 0.3 μm) was formed using Coating Liquid 2 instead of Coating Liquid 1.

[0128] (Preparation of Laminate) The first film and nylon film 1 (trade name: ONMB-RT, manufactured by Unitika Ltd., thickness 15 μm) were laminated using the solventless adhesive 2. The solventless adhesive 2 was applied to the surface of nylon film 1 using a roll coater at an adhesive temperature of 80 ° C. and a roll speed such that the thickness of the adhesive layer (solventless adhesive layer 2) formed after curing was 1.8 μm. Next, a sealant film 1 (polypropylene film, trade name: ZK207, manufactured by Toray Advanced Film Co., Ltd., thickness 60 μm) was prepared, and this film was laminated to the opposite side of the nylon film 1 from the first film using the solventless adhesive 2 in the same manner as above. Next, the solventless adhesive 2 was cured by aging for 96 hours in an environment of 40 ° C. This resulted in a laminate having a laminated structure of [barrier film 1 (alumina vapor deposition layer / anchor coat layer / PET film) / chlorine-containing layer 2 / solvent-free adhesive layer 2 / nylon film / solvent-free adhesive layer 2 / sealant film 1 (sealant layer 1)].

[0129] Example 6 (Preparation of nylon film with printed layer) A water-based flexographic ink (product name: Aquariona, manufactured by Toyo Ink Co., Ltd.) was printed on the corona-treated surface of nylon film 2 (product name: ON, manufactured by Unitika Ltd., thickness 15 μm, corona-treated) to prepare a nylon film with a printed layer having a thickness of 2 μm. The printed layer was a design layer having a printed portion and a plain portion, and the film thickness of the printed layer was measured in the plain portion.

[0130] (Preparation of Laminate) The resulting nylon film with a printed layer was laminated onto the surface of the first film prepared in Example 5 on the chlorine-containing layer 2 side using the solventless adhesive 1. The solventless adhesive 1 was applied to the surface of the printed layer of the nylon film with a printed layer using a roll coater at an adhesive temperature of 40°C and a roll speed such that the thickness of the adhesive layer (solventless adhesive layer 1) formed after curing was 1.8 µm. The solventless adhesive 1 was then cured by aging treatment for 48 hours in an environment of 40°C. This resulted in a laminate having a laminate structure of [nylon film 2 / printed layer / solventless adhesive layer 1 / chlorine-containing layer 2 / barrier film 1 (alumina vapor deposition layer / anchor coat layer / PET film)].

[0131] Example 7 A sealant film 2 (a low-density polyethylene film, product name: SE620, manufactured by Tamapoly Co., Ltd., thickness: 100 μm) was prepared, and this film was laminated onto the barrier film 1 side of the laminate of Example 6 before the aging treatment. Solventless adhesive 1 was applied to the barrier film 1 side of the laminate using a roll coater at an adhesive temperature of 40°C and at a roll speed such that the thickness of the adhesive layer (solventless adhesive layer 1) formed after curing was 1.8 μm. The solventless adhesive 1 was then cured by aging treatment for 48 hours in an environment of 40°C. This resulted in a laminate having a laminate structure of [nylon film 2 / printed layer / solventless adhesive layer 1 / chlorine-containing layer 2 / barrier film 1 (alumina vapor-deposited layer / anchor coat layer / PET film) / solventless adhesive layer 1 / sealant film 2 (sealant layer 2)].

[0132] Example 8 A laminate having a laminated structure of [nylon film 1 / solvent-free adhesive layer 1 / chlorine-containing layer 3 / barrier film 1 (alumina vapor-deposited layer / anchor coat layer / PET film)] was obtained in the same manner as in Example 1, except that chlorine-containing layer 3 (thickness: 1.0 μm) was formed using Coating Liquid 3 instead of Coating Liquid 1.

[0133] Example 9 A laminate having a laminated structure of [nylon film 1 / solvent-free adhesive layer 1 / chlorine-containing layer 3 / barrier film 1 (alumina vapor-deposited layer / anchor coat layer / PET film)] was obtained in the same manner as in Example 1, except that chlorine-containing layer 3 (thickness: 1.5 μm) was formed using Coating Liquid 3 instead of Coating Liquid 1.

[0134] Comparative Example 1 A laminate having a laminated structure of [nylon film 1 / solvent-free adhesive layer 1 / barrier film 1 (alumina vapor-deposited layer / anchor coat layer / PET film)] was obtained in the same manner as in Example 1, except that barrier film 1 was used instead of the first film (i.e., no chlorine-containing layer was formed).

[0135] Comparative Example 2 A laminate having a laminated structure of [nylon film 1 / solvent-free adhesive layer 1 / chlorine-containing layer 4 / barrier film 1 (alumina vapor-deposited layer / anchor coat layer / PET film)] was obtained in the same manner as in Example 1, except that chlorine-containing layer 4 (thickness: 0.3 μm) was formed using Coating Liquid 4 instead of Coating Liquid 1.

[0136] <Appearance Evaluation> Images of the appearance of the laminates produced in each example were taken using an optical microscope. The observation area (photographed area) was 10 cm x 10 cm. The bubble with the largest diameter (maximum diameter) was identified and the maximum diameter of the bubbles was compared. The area ratio of bubbles within the observation area was calculated from the same image. A good appearance was determined when the maximum diameter of the bubbles was 0.8 mm or less and the area ratio of bubbles was 6.0% or less. The appearance of the laminate was observed by observing the outside of the roll obtained by winding up 200 m of the laminate. The results are shown in Table 1. In Comparative Example 2, the chlorine-containing layer did not solidify, so measurement was not possible (marked "-" in the table).

[0137] <Measurement of Chlorine Amount> The amount of chlorine contained in the first film in the laminates obtained in the Examples and Comparative Examples was measured by combustion ion chromatography. Specifically, first, the solventless adhesive 1 was removed from the laminate, and films (nylon film, sealant film) other than the first film (a laminate of a chlorine-containing layer and a barrier film or a PET film) were removed. Next, the obtained first film was cut in its thickness direction. The obtained sample was collected as a combustion sample, placed on a ceramic board, and weighed. At this time, the weight of the combustion sample was approximately 30 mg. Next, the combustion sample was combusted under the following condition 1 using an automatic sample combustion device (AQF-2100H manufactured by Nitto Seiko Analytech Co., Ltd.), and the generated gas was collected in 10 mL of absorption liquid. After collection, the absorption liquid was adjusted to 15 mL with pure water to obtain an analytical sample, which was then subjected to quantitative analysis using ion chromatography (ICS-3000 manufactured by Thermo Fisher Scientific) under the following condition 2 to measure the chlorine concentration (% by mass) in the analytical sample. Note that, for Comparative Example 1, the amount of chlorine in Barrier Film 1 was measured, with Barrier Film 1 regarded as the first film.

[0138] (Condition 1) Inlet temperature: 900℃ Outlet temperature: 1000℃ Gas flow rate (O ２ Gas flow rate (Ar): 400 mL / min. Gas flow rate (Ar): 200 mL / min. Flow rate of humidifying Ar gas in the gas absorption unit when the generated gas is absorbed into the water absorbing liquid: 100 mL / min.

[0139] (Condition 2) Separation column: Dionex Ion Pac AS18 (4 mm x 150 mm) Guard column: Dionex Ion Pac AG18 (4 mm x 30 mm) Removal system (suppressor): Dionex ADRS-600 (external mode) Detector: electrical conductivity detector Eluent: KOH aqueous solution (eluent generator EGCIII used) Eluent flow rate: 1.2 mL / min Analysis sample injection volume: 250 μL

[0140]

[0141] 10...first film, 11...first substrate, 12...inorganic vapor deposition layer, 13...laminated film, 15...chlorine-containing layer, 20...second film, 21...second substrate, 22...printed layer, 30...third film, 100, 200...laminated body, S1...first adhesive layer, S2...second adhesive layer, S'1...first uncured layer, S'2...second uncured layer.

Claims

1. A laminate comprising a first film, a second film, and a first adhesive layer that bonds the first film and the second film together, wherein the first adhesive layer is formed using a urethane-based solventless adhesive, the first film includes a chlorine-containing layer that forms a contact surface with the first adhesive layer, and the chlorine content in the first film is 0.0005% by mass or more.

2. The chlorine-containing layer is a layer containing HCl and HClO ４ The laminate of claim 1 , comprising chlorine derived from at least one chlorine-based material selected from the group consisting of:

3. The laminate of claim 2, wherein said chlorine-containing layer comprises a reaction product of said chlorine-based material and an alkoxysilane.

4. The laminate of claim 1, wherein the chlorine-containing layer comprises a water-soluble polymer.

5. The laminate of claim 1, wherein the first film further comprises an inorganic vapor-deposited layer.

6. The laminate according to claim 5, wherein the inorganic vapor-deposited layer contains Al atoms or Si atoms.

7. The laminate according to claim 1, wherein the thickness of the first adhesive layer is 0.2 to 3.0 μm.

8. The laminate of claim 1, wherein the second film includes a printed layer.

9. The laminate according to claim 1, further comprising a third film laminated via a second adhesive layer on the side of the first film or the second film opposite to the first adhesive layer side.

10. The laminate of claim 1, including a sealant layer.

11. A packaging material comprising the laminate according to any one of claims 1 to 10.

12. A packaging bag made from the packaging material according to claim 11.

13. A method for manufacturing a laminate using a solvent-free adhesive, comprising: a step of preparing a first film including a chlorine-containing layer and having a chlorine content of 0.0005% by mass or more; and a lamination step of bonding the first film and a second film together using a urethane-based solvent-free adhesive, wherein in the lamination step, the first film and the second film are laminated together so that the chlorine-containing layer and the layer made of the urethane-based solvent-free adhesive are in contact with each other.

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