Laminate, method for producing the same, packaging bag, and package

Abstract

To provide a laminate capable of achieving superior design appearance while employing a solvent-free adhesive composition, and a method for producing the same.SOLUTION: A laminate comprising, in the following order, a base film 10, a print layer 50, a first adhesive layer S1, a metal layer 40, a second adhesive layer S2, and a sealant film 20, wherein the first adhesive layer S1 and the second adhesive layer S2 contain a solvent-free adhesive composition including a polyol component and a polyisocyanate component, a cured product thereof, or a mixture thereof, and the laminate has a first region 51 having an ink area ratio of 8% to 70%.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a laminate, a method for manufacturing the same, a packaging bag, and a package. [Background technology]

[0002] Packaging bags for containing and sealingly preserving beverages, food, etc. are known. Packaging bags are typically made by sealing a laminate of thin films. To impart a metallic luster to the surface of such packaging bags, a metal layer such as aluminum foil may be provided on the laminate. Various types of information, such as product, brand, and manufacturer, are printed on such laminates using a printing layer. Furthermore, an adhesive layer is provided to bond the layers of the laminate together.

[0003] From the viewpoint of reducing the environmental impact, development of adhesives that do not contain organic solvents (solvent-free adhesives) is underway. For example, Patent Document 1 proposes a two-component curing solvent-free adhesive containing a polyisocyanate component and a polyol component, and a composite film for packaging foods, beverages, medicines, quasi-drugs, etc. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2011-162656 Summary of the Invention [Problem to be solved by the invention]

[0005] A laminate having a metal layer may have a portion on the film where a design is printed and a portion where no design is printed and the metallic luster is emphasized. Because solvent-free adhesives have higher viscosity than solvent-based adhesives, air bubbles may be mixed into the adhesive during preparation or application. Therefore, when a solvent-free adhesive composition is used to bond a metal layer to a substrate film, the air bubbles may prevent the metal layer and the substrate film from adhering sufficiently, resulting in floating and unevenness in the surface after bonding. The metallic luster is impaired in areas where such unevenness occurs, reducing the design of the laminate. Therefore, the present disclosure provides a laminate and a method for manufacturing the same that have excellent designability even when using a solvent-free adhesive composition. Also provided are packaging bags and packaging bodies including such laminates. [Means for solving the problem]

[0006] One aspect of the present disclosure provides a laminate comprising, in this order, a base film, a printing layer, a first adhesive layer, a metal layer, a second adhesive layer, and a sealant film, wherein the first adhesive layer and the second adhesive layer contain a solventless adhesive composition containing a polyol component and a polyisocyanate component, a cured product thereof, or a mixture thereof, and the laminate has a first region with an ink area ratio of 8 to 70%.

[0007] The laminate has a first region with an ink area ratio of 8 to 70%, which disperses air bubbles in the adhesive and maintains the metallic luster of the surface. Therefore, lifting caused by air bubbles mixed in the adhesive composition is less noticeable, and unevenness can be suppressed. Therefore, the design of the laminate can be improved even when a solventless adhesive composition is used.

[0008] One aspect of the present disclosure provides a method for producing a laminate, the method comprising the steps of: forming a printed layer on one side of a substrate film; adhering the printed layer and a metal layer together using a solventless first adhesive composition containing a polyisocyanate component and a polyol component; adhering the metal layer and a substrate including a sealant film together using a solventless second adhesive composition containing a polyisocyanate component and a polyol component; and curing or semi-curing the first adhesive composition and the second adhesive composition to form a first adhesive layer and a second adhesive layer, thereby forming a laminate having a first region with an ink area ratio of 8 to 70%.

[0009] The method for producing the laminate described above forms a first region with an ink area ratio of 8 to 70%, which allows the printed layer to disperse air bubbles in the adhesive when adhering the metal layer. Furthermore, metallic luster can be maintained. Therefore, lifting due to air bubbles mixed in the adhesive composition can be made less noticeable. This suppresses the occurrence of unevenness on the metal layer after adhering, even when a solventless adhesive composition is used, thereby maintaining the uniformity of the metallic luster on the surface and improving the design of the laminate.

[0010] One aspect of the present disclosure provides a packaging bag constructed by heat-sealing the sealant films in the laminate described above. Because the packaging bag includes the laminate described above, unevenness on the metal layer can be reduced even when a solvent-free adhesive is used. Therefore, even when a solvent-free adhesive composition is used, the uniformity of the metallic luster on the surface can be maintained, improving the design of the packaging bag.

[0011] One aspect of the present disclosure provides a package including the above-described packaging bag and an item to be contained in the packaging bag. Because the package includes the above-described laminate, unevenness on the metal layer can be reduced even when a solvent-free adhesive is used. Therefore, even when a solvent-free adhesive composition is used, the uniformity of the metallic luster on the surface can be maintained, improving the design. [Effects of the Invention]

[0012] It is possible to provide a laminate having excellent design properties and a method for producing the same, even when a solventless adhesive composition is used. It is also possible to provide a packaging bag and a package including such a laminate. [Brief explanation of the drawings]

[0013] [Figure 1] FIG. 2 is a plan view showing an example of a laminate; [Figure 2] 2 is a cross-sectional view of the first region 51 of FIG. 1 taken along line II-II. [Figure 3] 3 is a cross-sectional view of the second region 52 of FIG. 1 taken along line III-III. [Figure 4] FIG. 1 is a diagram showing an example of a laminating device used when bonding with a solventless adhesive composition. [Figure 5] FIG. 1 is a diagram showing an example of a laminating device used when bonding with a solvent-based adhesive composition. [Figure 6] FIG. 2 is a plan view showing an example of a packaging bag and a packaging body. [Figure 7] FIG. 10 is a perspective view showing another example of a packaging bag. [Figure 8] 1(a) is a photograph of the surface of the laminate in Example 1 observed with a microscope, and FIG. 1(b) is a diagram in which surface unevenness has been emphasized by binarizing FIG. [Figure 9] 1(a) is a photograph of the surface of the laminate in Example 2 observed with a microscope, and FIG. 1(b) is a diagram in which surface unevenness has been emphasized by binarizing FIG. [Figure 10] 1(a) is a photograph of the surface of the laminate in Example 3 observed with a microscope, and FIG. 1(b) is a diagram in which surface unevenness has been emphasized by binarizing FIG. [Figure 11] 1(a) is a photograph of the surface of the laminate in Example 4 observed with a microscope, and FIG. 1(b) is a diagram in which surface unevenness has been emphasized by binarizing FIG. [Figure 12] 1(a) is a photograph of the surface of the laminate in Comparative Example 1 observed with a microscope, and FIG. 1(b) is a diagram in which FIG. 1(a) has been binarized to emphasize the unevenness of the surface. DETAILED DESCRIPTION OF THE INVENTION

[0014] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings as needed. However, the following embodiments are merely examples for explaining the present disclosure and are not intended to limit the present disclosure to the following content. In the description, the same elements or elements having the same functions will be designated by the same reference numerals, and redundant description will be omitted where appropriate. Furthermore, unless otherwise specified, positional relationships such as up, down, left, and right will be based on the orientation of the reference numerals shown in the drawings. Furthermore, the dimensional ratios of each element are not limited to those shown in the drawings.

[0015] Unless otherwise specified, the materials exemplified in this disclosure can be used singly or in combination of two or more. When multiple substances corresponding to each component are present in the composition, the content of each component in the composition refers to the total amount of the multiple substances present in the composition unless otherwise specified. In this disclosure, numerical ranges indicated using "to" indicate ranges that include the respective numerical values ​​before and after "to" as minimum and maximum values. In this disclosure, individual upper and lower limit values ​​can be arbitrarily combined.

[0016] <Laminate> Fig. 1 is a plan view showing an example of a laminate. The laminate 100 has a first region 51 and a second region 52. The first region 51 is, for example, a region where no image is printed, and the second region 52 is a region where an image is printed. The first region 51 has an ink coverage of 8 to 70%. The second region 52 has an ink coverage of 100%.

[0017] FIG. 2 is a cross-sectional view of the first region 51 in FIG. 1 taken along line II-II. FIG. 2 shows a cross-section along the lamination direction (thickness direction) of the laminate 100. The laminate 100 has, in this order, a base film 10, a printed layer 50, a first adhesive layer S1, a metal layer 40, a second adhesive layer S2, and a sealant film 20. A printed surface 55 is provided on the base film 10. The printed layer 50 is provided on the printed surface 55. The printed layer 50 and the base film 10 are in contact with each other, and the printed layer 50 and the first adhesive layer S1 are in contact with each other. The printed layer 50 is in the form of discontinuous halftone dots, formed in an island shape. The first adhesive layer S1 and the second adhesive layer S2 contain a solventless adhesive composition.

[0018] The substrate film 10 may have a flexible substrate. The flexible substrate may include, for example, a thermoplastic polymer film. Examples of flexible substrates include biaxially oriented polypropylene (OPP), biaxially oriented polypropylene (BOPP), polyethylene terephthalate (PET), oriented polyamide (OPA), solid polypropylene (CPP), linear low-density polyethylene (LLDPE), low-density polyethylene (LDPE), and nylon film.

[0019] The base film 10 may include, for example, a vapor-deposited film (transparent vapor-deposited film) having a resin layer such as a PET film and a barrier layer (vapor-deposited layer) on the resin layer. This can improve the sealing performance when the laminate 100 is used as a packaging material. Examples of the barrier layer include a vapor-deposited layer of a metal oxide (for example, silica or alumina). The thickness of the base film 10 may be 7 to 150 μm, 10 to 100 μm, or 12 to 80 μm. A specific example of a transparent vapor-deposited film is a transparent vapor-deposited PET film in which a transparent vapor-deposited layer is formed on a PET film. The base film 10 may include a nylon film such as a barrier nylon film.

[0020] The laminate 100 has a first region 51 with an ink area ratio of 8 to 70%. The ink area ratio represents the ratio of the area of ​​halftone dots actually printed per unit area. For example, if the printed halftone dots are large and adjacent halftone dots completely overlap each other, printing ink over the entire unit area, the ink area ratio is 100%. Furthermore, if no halftone dots are printed in the unit area, the ink area ratio is 0% (plain area). The ink area ratio can be determined by observing the main surface of the laminate 100 with an optical microscope or the like and calculating the ratio of the area of ​​the halftone dots (printed layer 50) to the total area of ​​an arbitrary observation area. Specifically, the automatic area measurement function of an optical microscope (Keyence Corporation, Model No. VHX-6000) is used to extract the halftone dots, and the ratio of the total area of ​​the halftone dots to the area of ​​the observation area is calculated. The observation area may be, specifically, 1 mm square or 3 mm square.

[0021] Having a first region 51 with an ink coverage of 8 to 70% means that the ink coverage may be 8 to 70% in a portion of the laminate 100, but does not mean that the ink coverage is 8 to 70% over the entire surface of the laminate 100. Therefore, in order to form a pattern, the ink coverage of a portion of the laminate 100 may be other than 8 to 70%, for example, 100%. The ink coverage of the portion of the laminate 100 other than the first region 51 may be greater than 70%, or may be 100%. The laminate 100 may be composed of only the first region 51 and the second region 52. In a modified example, the laminate may have a region with an ink coverage of less than 8%, or may have a plain region with an ink coverage of 0%. In another modified example, the laminate may be composed of only the first region 51 and a region with an ink coverage of less than 8%. The range of the first region 51 may be an observation range for observing halftone dots, and specifically, may be 1 mm square or 3 mm square.

[0022] Because solventless adhesive compositions do not contain solvents, they tend to trap air bubbles inside during preparation or application, which reduces adhesion to the metal layer 40. When adhesion between the metal layer 40 and the adhesive composition is reduced, unevenness due to floating occurs on the metal layer 40. The unevenness causes color changes in the areas where the metallic luster is reduced, reducing the uniformity of the metallic luster and the design of the laminate 100. Meanwhile, in the first region 51 with an ink area ratio of 8 to 70%, when the printed layer 50 and the metal layer 40 are bonded together with the solventless adhesive composition, the printed layer 50 can disperse air bubbles in the adhesive composition. Therefore, the adhesive composition and the metal layer 40 can be sufficiently adhered to each other. This reduces the noticeable floating of air bubbles in the solventless adhesive composition, suppressing unevenness on the metal layer 40, and improving the design of the laminate 100 even when using a solventless adhesive.

[0023] The ink area ratio in the first region 51 may be 10% or more, 15% or more, or 20% or more from the viewpoint of further increasing the pressure from the printing layer 50 to the adhesive composition and further suppressing the occurrence of unevenness. Furthermore, the ink area ratio in the first region 51 may be 60% or less, 50% or less, or 40% or less from the viewpoint of sufficiently maintaining the metallic luster of the surface. The range of the ink area ratio in the first region 51 may be, for example, 10 to 60% or 20 to 50%. The color of the ink in the first region 51 may be white from the viewpoint of not making the ink color stand out and sufficiently maintaining the metallic luster of the metal layer 40.

[0024] The ink coverage of the laminate 100 may be 500% or less. By setting the ink coverage to 500% or less, the thickness of the printed layer 50 can be reduced. The ink coverage represents the ratio of halftone dot area per unit area set by the printing press. The desired value of the ink coverage can be set on the printing press; if the ink coverage is set to 200%, the printing press will apply one overcoat, and if the ink coverage is set to 300%, the printing press will apply two overcoats. If the ink coverage is 100% or more, the ink coverage remains 100%. When printing with multiple colors of ink, the ink coverage for each color of ink can be calculated, and the sum of these can be used as the ink coverage of the laminate 100. From the perspective of further reducing the thickness of the printed layer 50, the ink coverage of the laminate 100 may be 400% or less, or 300% or less.

[0025] When the ink coverage is less than 100%, the ink coverage correlates with the ink coverage. In this case, the actual printed dots are spread out, so the ink coverage is greater than the set ink coverage. Therefore, you can adjust the ink coverage by adjusting the ink coverage.

[0026] A primer layer may be provided between the base film 10 and the printed layer 50, and the printed layer 50 may contain an electrostatic ink composition. Although electrostatic ink compositions tend to have low adhesion to solventless adhesive compositions, by setting the ink area ratio to 8 to 70%, air bubbles in the adhesive composition can be sufficiently dispersed, further improving adhesion. Therefore, when the printed layer 50 contains an electrostatic ink composition, adhesion to the metal layer 40 can be further improved and unevenness on the metal layer 40 can be further suppressed. The electrostatic ink composition can be applied using, for example, a digital printing machine (e.g., HP's Indigo 20000 label and packaging digital printing machine).

[0027] The primer layer may contain a resin. Examples of the resin include polyvinyl alcohol resin, cellulose-based resin, polyester, polyamine, polyethyleneimine resin, polyamide resin, polyurethane, polyacrylic polymer, hydroxyl-containing resin, carboxyl-containing resin, and amine-based polymer. The presence of the primer layer allows smooth printing of the electrostatic ink composition using a digital printing machine. Furthermore, the adhesion of the electrostatic ink composition to the primer layer can be improved. The coating amount of the resin constituting the primer layer is, for example, 0.01 to 1.5 g / m. 2 and may be 0.05 to 1.0 g / m 2 may be.

[0028] The electrostatic ink composition is an ink composition used in liquid electrophotographic printing, i.e., electrostatic printing, and may be printed on a primer layer. The electrostatic ink composition may contain a colorant or pigment, such as a dye, and a resin. In addition to these, the electrostatic ink composition may also contain a carrier fluid or carrier liquid. It may also contain a charge director, a charge adjuvant, a surfactant, a viscosity modifier, an emulsifier, and other additives. It may also contain a component (e.g., a polyisocyanate component) that permeates through the first adhesive layer S1 and the second adhesive layer S2.

[0029] Examples of colorants include cyan pigments, magenta pigments, yellow pigments, and black pigments. To facilitate digital printing, resins with relatively low melting points (e.g., 100°C or less) can be used. Examples of resins include thermoplastic resins such as ethylene acrylic acid copolymers, propylene acrylic acid copolymers, ethylene methacrylic acid copolymers, propylene methacrylic acid copolymers, and ethylene vinyl acetate copolymers. The resin preferably contains at least one of ethylene acrylic acid copolymers and ethylene methacrylic acid copolymers.

[0030] Carrier fluids and carrier liquids include hydrocarbons, silicone oils, and vegetable oils. Hydrocarbons include aliphatic hydrocarbons, branched-chain aliphatic hydrocarbons, and aromatic hydrocarbons. The electrostatic ink composition may be substantially free of carrier liquid when printed onto a printing substrate, such as the substrate film 10. The carrier liquid may be removed, for example, by an electrophoretic process or evaporation during printing, thereby transferring substantially only solids to the printing substrate.

[0031] Charge directors function to maintain a sufficient electrostatic charge on particles contained in the electrostatic ink composition, and include, for example, ionic compounds such as metal salts of fatty acids, metal salts of sulfosuccinates, metal salts of oxyphosphates, metal salts of alkylbenzenesulfonic acids, and metal salts of aromatic carboxylic or aromatic sulfonic acids, as well as zwitterionic and nonionic compounds such as polyoxyethylenated alkylamines, lecithin, polyvinylpyrrolidone, and organic acid esters of polyhydric alcohols.

[0032] Charge adjuvants have the effect of increasing or stabilizing the charge of particles contained in the electrostatic ink composition. Examples of charge adjuvants include barium petronate, calcium petronate, Co naphthenate, Ca naphthenate, Cu naphthenate, Mn naphthenate, Ni naphthenate, Zn naphthenate, Fe naphthenate, Ba stearate, Co stearate, Pb stearate, Zn stearate, Al stearate, Cu stearate, Fe stearate, and metal carboxylates.

[0033] The electrostatic ink composition may contain a crosslinked product crosslinked by components contained in the first adhesive layer S1 and / or the primer layer. This can sufficiently increase the strength of the printed layer 50 itself, as well as the adhesive strength between the printed surface 55 and the printed layer 50, and between the printed layer 50 and the first adhesive layer S1 and / or the primer layer. It can also prevent gaps from forming at the interface between the printed layer 50 and the first adhesive layer S1. This can improve the adhesive strength of the first adhesive layer S1.

[0034] The thickness of the first adhesive layer S1 may be 0.5 to 5 μm, 0.6 to 3 μm, or 0.8 to 2 μm, thereby achieving a good balance between adhesive strength and design.

[0035] The thickness of each layer constituting the laminate 100 can be measured by observing the cross section of the laminate 100 with a digital microscope.

[0036] The first adhesive layer S1 contains a solvent-free adhesive composition, a cured product thereof, or a mixture thereof. The adhesive composition may be a two-component curing type. The first adhesive layer S1 contains two components: a polyisocyanate component and a polyol component. At least a portion of these components may react with each other to form a cured product. The cured product may also contain polyurethane. The first adhesive layer S1 containing the above two components is in direct contact with the printed layer 50 and the metal layer 40. Being a solvent-free adhesive reduces the environmental impact.

[0037] When the printed layer 50 contains an electrostatic ink composition, the polyol component and polyisocyanate component contained in the adhesive composition penetrate into the electrostatic ink composition, agglomerating the printed layer 50 containing the electrostatic ink composition, sufficiently increasing the adhesive strength with the metal layer 40, suppressing the occurrence of surface unevenness, and further improving the design of the laminate 100.

[0038] The polyisocyanate component may contain a hexamethylene diisocyanate derivative (hereinafter, sometimes referred to as an "HDI derivative"). It is believed that hexamethylene diisocyanate derivatives tend to easily penetrate or become compatible with electrostatic ink compositions. This further increases the cohesive force of the printing layer 50 containing the electrostatic ink composition, thereby further increasing the adhesive strength of the first adhesive layer S1. This also sufficiently increases the adhesive strength with the metal layer 40, suppresses the occurrence of surface unevenness, and further improves the design of the laminate 100.

[0039] The HDI derivative may be a bifunctional derivative of hexamethylene diisocyanate. HDI derivatives are aliphatic diisocyanates and are more easily permeated into the electrostatic ink composition than aromatic diisocyanates. This allows the printed layer 50 containing the electrostatic ink composition to blend well with the first adhesive layer S1, improving the cross-linking effect between the first adhesive layer S1 and the printed layer 50. This improves the adhesion between the printed layer 50 and the first adhesive layer S1, further increasing the adhesive strength of the first adhesive layer S1. This also sufficiently increases the adhesive strength with the metal layer 40, suppressing the occurrence of surface unevenness and further improving the design of the laminate 100.

[0040] The HDI derivative may be a trifunctional derivative of HDI (hexamethylene diisocyanate). Such a trifunctional derivative penetrates the printed layer 50 containing the electrostatic ink composition and crosslinks with the components of the electrostatic ink composition. This increases the cohesive force of the printed layer 50 and further increases the adhesive strength of the laminate 100. By including both a bifunctional derivative and a trifunctional derivative as the HDI derivative, the HDI derivative can be sufficiently penetrated into the electrostatic ink composition and further promote the crosslinking reaction with the components of the printed layer 50. This can further increase the adhesive strength of the first adhesive layer S1 even when the printed layer 50 is thick. This also sufficiently increases the adhesive strength with the metal layer 40, suppresses surface unevenness, and further improves the design of the laminate 100.

[0041] In the first adhesive layer S1 (adhesive composition), the content of the trifunctional derivative of HDI may be higher than the content of the bifunctional derivative of HDI. This allows a crosslinking reaction to proceed in the first adhesive layer S1 and the printed layer 50 containing the electrostatic ink composition, improving the strength of the first adhesive layer S1 and the printed layer 50 and sufficiently increasing the adhesive strength between the first adhesive layer S1 and the printed layer 50. This also sufficiently increases the adhesive strength with the metal layer 40, suppresses the occurrence of surface unevenness, and further improves the design of the laminate 100. From this perspective, the mass ratio of the trifunctional derivative to the total of the bifunctional derivative and the trifunctional derivative may be 55% by mass or more, or may be 60% by mass or more. On the other hand, from the perspective of maintaining the flexibility of the first adhesive layer S1 and the printed layer 50, the mass ratio of the trifunctional derivative to the total of the bifunctional derivative and the trifunctional derivative may be 85% by mass or less, 80% by mass or less, or 75% by mass or less. An example of the mass ratio of the trifunctional derivative to the total of the bifunctional derivative and the trifunctional derivative is 55 to 85 mass %.

[0042] Examples of HDI derivatives include HDI multimers (e.g., dimers, trimers, pentamers, heptamers, etc.), biuret-modified products (e.g., biuret-modified products produced by the reaction of HDI with water, tertiary alcohols, or amines), allophanate-modified products (e.g., allophanate-modified products produced by the reaction of HDI with alcohols), urea-modified products (e.g., urea-modified products produced by the reaction of HDI with diamines), oxadiazinetrione (e.g., oxadiazinetrione produced by the reaction of HDI with carbon dioxide), carbodiimide-modified products (e.g., carbodiimide-modified products produced by the decarboxylation condensation reaction of HDI), and polyol-modified products. HDI may also be an adduct of HDI with trimethylolpropane.

[0043] The content of the HDI derivative in the polyisocyanate component may be 15% by mass or more, 20% by mass or more, or 25% by mass or more. This allows the above-mentioned effects to be fully exhibited. The content of the HDI derivative in the polyisocyanate component may be 60% by mass or less, 50% by mass or less, or 40% by mass or less. An example of the content of the HDI derivative in the polyisocyanate component is 15 to 60% by mass.

[0044] The polyisocyanate component may further contain a polyisocyanate having two or more isocyanate groups in one molecule, which is different from the HDI derivative. This allows for flexibility in designing the laminate 100 according to the desired properties. Examples of such polyisocyanate monomers include aromatic diisocyanates, aromatic alicyclic diisocyanates, aliphatic diisocyanates, and alicyclic diisocyanates.

[0045] Aromatic diisocyanates are highly reactive and easily cured, which allows for rapid production of the laminate 100. Examples of aromatic aliphatic diisocyanates include m- or p-phenylene diisocyanate or a mixture thereof, 2,4- or 2,6-tolylene diisocyanate or a mixture thereof (TDI), 4,4'-, 2,4'-, or 2,2'-diphenylmethane diisocyanate or a mixture thereof (MDI), 4,4'-toluidine diisocyanate (TODI), 4,4'-diphenyl ether diisocyanate, 4,4'-diphenyl diisocyanate, and 1,5-naphthalene diisocyanate (NDI).

[0046] Examples of the araliphatic diisocyanate include 1,3- or 1,4-xylylene diisocyanate or a mixture thereof (XDI), 1,3- or 1,4-tetramethylxylylene diisocyanate or a mixture thereof (TMXDI), and ω,ω'-diisocyanato-1,4-diethylbenzene.

[0047] Examples of the aliphatic diisocyanate include trimethylene diisocyanate, tetramethylene diisocyanate, pentamethylene diisocyanate, 1,2-, 2,3- or 1,3-butylene diisocyanate, and 2,4,4- or 2,2,4-trimethylhexamethylene diisocyanate.

[0048] Examples of alicyclic diisocyanates include 1,3-cyclopentene diisocyanate, 1,4-cyclohexane diisocyanate, 1,3-cyclohexane diisocyanate, 3-isocyanatomethyl-3,5,5-trimethylcyclohexyl isocyanate (isophorone diisocyanate; IPDI), 4,4'-, 2,4'-, or 2,2'-dicyclohexylmethane diisocyanate or mixtures thereof (hydrogenated MDI), methyl-2,4-cyclohexane diisocyanate, methyl-2,6-cyclohexane diisocyanate, 1,3- or 1,4-bis(isocyanatomethyl)cyclohexane or mixtures thereof (hydrogenated XDI).

[0049] The polyisocyanate component may contain a derivative of the polyisocyanate monomer (polyisocyanate derivative). Examples of the polyisocyanate derivative include (for example, a dimer, trimer, pentamer, heptamer, etc.), allophanate-modified products (for example, an allophanate-modified product produced by reacting a polyisocyanate monomer with an alcohol), biuret-modified products (for example, a biuret-modified product produced by reacting a polyisocyanate monomer with water or an amine), urea-modified products (for example, a urea-modified product produced by reacting a polyisocyanate monomer with a diamine), oxadiazinetrione (for example, oxadiazinetrione produced by reacting a polyisocyanate monomer with carbon dioxide), and carbodiimide-modified products (for example, a carbodiimide-modified product produced by a decarboxylation condensation reaction of a polyisocyanate monomer).

[0050] The polyisocyanate component may include an isocyanate-terminated prepolymer. The isocyanate-terminated prepolymer is a urethane prepolymer having at least two isocyanate groups at the molecular end. The urethane prepolymer can be obtained by a urethane reaction between at least one member selected from the group consisting of a polyisocyanate monomer, a polyisocyanate derivative, and an isocyanate-terminated prepolymer and a polyol.

[0051] The polyol component may contain at least one selected from the group consisting of polyester polyols and polyether polyols. Among these, polyether polyols may be included from the viewpoints of reducing production costs and suppressing hydrolysis.

[0052] The polyether polyol may be a polyalkylene oxide. For example, it may be obtained by addition reaction of an alkylene oxide such as ethylene oxide and / or propylene oxide with a low molecular weight polyol as an initiator. Specific examples include polyethylene glycol, polypropylene glycol, and polyethylene polypropylene glycol (random or block copolymer). Other examples include polytetramethylene ether glycol obtained by ring-opening polymerization of tetrahydrofuran.

[0053] The polyester polyol can be obtained, for example, by a condensation reaction or transesterification reaction between a polyhydric alcohol and a polybasic acid, its alkyl ester, its acid anhydride, or its acid halide. Examples of the polyhydric alcohol include low-molecular-weight diols, low-molecular-weight triols, and low-molecular-weight polyols having four or more hydroxyl groups.

[0054] Examples of low molecular weight diols include ethylene glycol, propylene glycol, trimethylene glycol, 1,4-butylene glycol, 1,3-butylene glycol, 1,2-butylene glycol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, 2,2-dimethyl-1,3-propanediol, neopentyl glycol, 1,6-hexanediol, 2,2-diethyl-1,3-propanediol, 3,3-dimethylolheptane, and 2-ethyl-2-butyl-1,3-propanediol.

[0055] Examples of low molecular weight triols include glycerin, 2-methyl-2-hydroxymethyl-1,3-propanediol, 2,4-dihydroxy-3-hydroxymethylpentane, 1,2,6-hexanetriol, trimethylolethane, trimethylolpropane, 2-methyl-2-hydroxymethyl-1,3-propanediol, 2,4-dihydroxy-3-(hydroxymethyl)pentane, and 2,2-bis(hydroxymethyl)-3-butanol.

[0056] Examples of low molecular weight polyols having four or more hydroxyl groups include tetramethylolmethane, pentaerythritol, dipentaerythritol, D-sorbitol, xylitol, D-mannitol, and D-mannite.

[0057] Examples of alkyl esters of polybasic acids include methyl esters and ethyl esters of polybasic acids. Examples of acid anhydrides include acid anhydrides derived from polybasic acids, such as oxalic anhydride, succinic anhydride, maleic anhydride, phthalic anhydride, 2-alkyl (C12 to C18) succinic anhydride, tetrahydrophthalic anhydride, and trimellitic anhydride.

[0058] The acid halides include those derived from the above-mentioned polybasic acids, such as oxalic acid dichloride, adipic acid dichloride, and sebacic acid dichloride.

[0059] In the first adhesive layer S1 (adhesive composition), the mass ratio of the polyisocyanate component may be higher than the mass ratio of the polyol component. Specifically, the mass ratio of the polyisocyanate component to the polyol component may be 1 or more, 1.2 or more, or even 1.4 or more. In this way, by increasing the mass ratio of the polyisocyanate component to the polyol component, the curing reaction is promoted and the adhesion and curing steps can be sufficiently shortened. From the same viewpoint, the mass ratio of the polyisocyanate component to the polyol component may be 4 or less, or even 3 or less. An example of the mass ratio of the polyisocyanate component to the polyol component is 1 to 4.

[0060] The second adhesive layer S2, like the first adhesive layer S1, contains a solventless adhesive composition containing a polyol component and a polyisocyanate component, a cured product thereof, or a mixture thereof. The same description of the first adhesive layer S1 can be applied to the second adhesive layer S2 as is. The first adhesive layer S1 and the second adhesive layer S2 may contain the same components or different components.

[0061] The adhesive composition constituting the first adhesive layer S1 and the second adhesive layer S2 may contain optional components such as additives in addition to the polyisocyanate component and the polyol component. Examples of additives include antioxidants, UV absorbers, light stabilizers, fillers, silane coupling agents, epoxy resins, catalysts, coatability improvers, leveling agents, nucleating agents, lubricants, release agents, antifoaming agents, plasticizers, surfactants, pigments, dyes, organic fine particles, inorganic fine particles, antifungal agents, and flame retardants. The adhesive composition is solventless and does not contain solvents such as organic solvents. This reduces the environmental impact and significantly improves the working environment. Solventless adhesive compositions are heated during application.

[0062] The printing method for the printed layer 50 is not limited to digital printing, but may also be gravure printing, flexographic printing, or offset printing. In this case, ink appropriate for each printing method can be used. The ink may be a solvent-based ink, or from an environmental perspective, a water-based ink. Furthermore, the surface of the base film 10 may be subjected to a surface treatment such as corona treatment or plasma treatment to improve the adhesion of the printed layer 50.

[0063] When performing gravure printing, the ink coverage can be adjusted, for example, by adjusting the depth and density of fine cells engraved in the plate that transfer the ink. When performing gravure printing, the laminate 100 may have an anchor coat layer and a medium layer on the printing layer 50 to improve the adhesiveness of the printing layer 50.

[0064] Examples of the sealant film 20 include a non-oriented polypropylene film (CPP film), a linear low-density polyethylene film (LLDPE film), and a low-density polyethylene film (LDPE film). The thickness of the sealant film 20 may be 10 to 150 μm, 20 to 100 μm, or 30 to 80 μm.

[0065] The metal layer 40 may contain aluminum foil. When the metal layer 40 contains aluminum foil, the laminate 100 can have a metallic luster and can have improved barrier properties. Furthermore, when the solventless adhesive composition contains a surface modifier, the adhesion between the first adhesive layer S1 and the second adhesive layer S2 and the metal layer 40 can be further improved. This can further suppress the occurrence of surface unevenness due to lifting, and can further improve the design of the laminate 100. The thickness of the metal layer 40 may be 1 to 20 μm, 3 to 15 μm, or 5 to 10 μm.

[0066] The metal layer 40 may be a vapor-deposited layer. The vapor-deposited layer may be formed by, for example, vacuum film formation. In the vacuum film formation, physical vapor deposition or chemical vapor deposition may be used. Examples of physical vapor deposition include vacuum deposition, sputtering, and ion plating. Examples of chemical vapor deposition include thermal CVD, plasma CVD, and photo-CVD. When a vapor-deposited layer is used as the metal layer, a vapor-deposited film having a metal layer and a resin film may be provided instead of the metal layer 40. Specific examples of vapor-deposited films include an AL-deposited PET film in which an AL-deposited layer is formed on a PET film, and a transparent vapor-deposited PET film in which a transparent vapor-deposited layer is formed on a PET film.

[0067] Examples of the surface modifier include those containing at least one selected from sulfamic acid, phosphoric acid, nitric acid, hydroxypropyl cellulose, hydroxypropyl methyl cellulose, hydroxyethyl methyl cellulose, and ethyl hydroxyethyl cellulose.

[0068] The laminate 100 may have a second region 52 with an ink coverage of 100% or more. Figure 3 shows a cross-sectional view of the second region 52 in Figure 1 taken along line III-III. The second region 52 refers to, for example, a portion where a pattern is printed over the entire surface. As shown in Figure 3, in the second region 52, the printing layer 50 is printed over the entire surface of the base film 10. Since the ink coverage of the second region 52 is 100% or more, the ink area ratio is 100%.

[0069] The laminate 100 has a second region 52 with an ink coverage of 100% or more, which increases the pressure difference with the first region 51. This prevents bubbles from concentrating at the boundary between the first region 51 and the second region 52, allowing bubbles in the solventless adhesive composition to be sufficiently dispersed, further reducing the occurrence of unevenness. For example, when the first region 51 and the second region 52 are adjacent to each other as shown in FIG. 1, bubbles in the adhesive composition are dispersed from the second region 52 to the first region 51, thereby further reducing the occurrence of unevenness throughout the laminate 100. The size of the second region 52 may be within the observation range, similar to the first region 51, and may be, for example, 1 mm square or 3 mm square. From the perspective of further increasing the pressure difference with the first region 51, the ink coverage of the second region 52 may be 150% or more, 200% or more, or 300% or more.

[0070] The laminate 100 of the present disclosure is not limited to the laminate structure of FIG. 2 or 3. For example, it may have the following laminate structure. In each example, the leftmost layer is the substrate film 10, and the rightmost layer is the sealant film 20. In each example, the layers are arranged in order from left to right. The third adhesive layer described below may be the same adhesive layer as the first adhesive layer S1 and the second adhesive layer S2, or may be a different adhesive layer. Note that the laminate structure of the laminate is not limited to the following examples.

[0071] Example 1) PET film / printed layer / first adhesive layer / metal layer / second adhesive layer / LLDPE film (linear low-density polyethylene film) Example 2) PET film / primer layer / printing layer / first adhesive layer / aluminum foil / second adhesive layer / LDPE film Example 3) Nylon film / printed layer / first adhesive layer / metal layer / second adhesive layer / LLDPE film Example 4) Transparent vapor-deposited PET film / printed layer / first adhesive layer / metal layer / second adhesive layer / CPP film (non-oriented polypropylene film) Example 5) Barrier nylon film / printed layer / first adhesive layer / metal layer / second adhesive layer / CPP film Example 6) Transparent vapor-deposited PET film / printed layer / first adhesive layer / metal layer / second adhesive layer / nylon film / third adhesive layer / CPP film Example 7) Transparent vapor-deposited PET film / primer layer / printed layer / first adhesive layer / aluminum foil / second adhesive layer / nylon film / third adhesive layer / CPP film Example 8) Transparent vapor-deposited PET film / printed layer / first adhesive layer / metal layer / second adhesive layer / PET film / third adhesive layer / CPP film Example 9) OPP film / primer layer / printing layer / first adhesive layer / metal layer / second adhesive layer / CPP film Example 10) OPP film / printed layer / first adhesive layer / metal layer / second adhesive layer / CPP film Example 11) OPP film / printed layer / first adhesive layer / metal layer / second adhesive layer / LLDPE film Example 12) Nylon film / printed layer / first adhesive layer / metal layer / second adhesive layer / CPP film Example 13) PET film / printed layer / first adhesive layer / metal layer / second adhesive layer / CPP film Example 14) PET film / printed layer / first adhesive layer / metal layer / second adhesive layer / LLDPE film Example 15) PET film / printed layer / first adhesive layer / metal layer / second adhesive layer / LDPE film Example 16) PET film / printed layer / first adhesive layer / metal layer / second adhesive layer / nylon film / third adhesive layer / LLDPE film

[0072] <Method of manufacturing laminate> An example of a method for manufacturing a laminate is described below. The method for manufacturing the laminate 100 includes the steps of forming a printed layer 50 on one side of a substrate film 10, bonding the printed layer 50 and one side of a metal layer 40 together using a solventless first adhesive composition containing a polyisocyanate component and a polyol component, bonding the metal layer 40 and a substrate including a sealant film 20 together using a solventless second adhesive composition containing a polyisocyanate component and a polyol component, and curing or semi-curing the first and second adhesive compositions to form a first and second adhesive layer, thereby forming a laminate having a first region with an ink area ratio of 8 to 70%.

[0073] The printing layer 50 and the printing surface 55 may be formed by a known method such as gravure printing, flexographic printing, offset printing, or digital printing. A commercially available printing machine can be used. For digital printing, for example, the HP Indigo 20000 label and packaging digital printing machine can be used. By adjusting the ink coverage setting of the printing machine, the ink coverage of the printing layer 50 can be adjusted to 8 to 70%.

[0074] A step of forming a primer layer on one side of the substrate film 10 may be performed before the step of forming the printed layer 50. The primer layer may be formed on one side of the substrate film 10 by flexographic printing or gravure printing. The primer layer may be formed by crosslinking a resin raw material with a crosslinking agent. Crosslinking may be performed by irradiating with ultraviolet light, heat, ionizing radiation such as an electron beam, or non-ionizing radiation such as microwave radiation. After forming the primer layer, an electrostatic ink composition may be printed on the primer layer as the printed layer 50. The printing of the electrostatic ink composition may be performed by electrostatic printing using a digital printing machine. For example, an HP Indigo 20000 label and packaging digital printing machine may be used as the digital printing machine. In this manner, the printed layer 50 containing the electrostatic ink composition may be formed, thereby obtaining the printed surface 55.

[0075] Bonding of the printed surface 55 and one side of the metal layer 40 with the first adhesive composition may be performed as follows. FIG. 4 shows an example of a laminating apparatus equipped with a roll coater used for bonding with the solventless first adhesive composition. The laminating apparatus 200 includes a roll coater 210 made up of a combination of multiple rolls, and a solventless first adhesive composition 220 that is fed into the roll coater 210. The first adhesive composition 220 supplied to the roll coater 210 is heated to approximately 40 to 90°C and melted. Meanwhile, the base film 10 or the metal layer 40 travels from the film roll 201 in the direction of the arrow in FIG. 4. The first adhesive composition 220 is applied to the printed surface 55 of the base film 10 or one side of the metal layer 40 by the roll coater 210.

[0076] The first adhesive composition on the printed surface 55 coated by the roll coater 210 or the first adhesive composition on the metal layer 40 is placed opposite the bonding surface of the other substrate, and the first adhesive composition is bonded to the bonding surface of the other substrate using a nip roll 230. The laminated film thus bonded is wound up to obtain a raw roll 240. Aging of the raw roll 240 promotes curing of the first adhesive composition, forming a first adhesive layer S1. In this manner, the base film 10, the printed layer 50, the first adhesive layer S1, and the metal layer 40 can be laminated in this order. The aging temperature may be 20 to 50°C, and the aging time may be 0.5 to 5 days.

[0077] Furthermore, a second adhesive composition is applied to the surface of the metal layer 40 opposite the first adhesive layer S1, and a sealant film 20 is laminated thereon. The process of applying the second adhesive composition to form the second adhesive layer S2 is similar to the process of forming the first adhesive layer S1. That is, as shown in FIG. 4, a second adhesive composition that has been heated to approximately 40 to 90°C and melted is further applied. This application of the adhesive composition may also be performed using a roll coater 210 combining multiple rolls. Thereafter, the applied second adhesive composition 220 and the sealant film 20 are bonded together using a nip roll 230 so that they face each other. This laminated film is wound up and the resulting raw roll 240 is then aged. Through aging, the second adhesive composition is cured or semi-cured by a urethanization reaction, forming a second adhesive layer S2 containing a cured product, and forming a laminate 100 having a first region 51 with an ink area ratio of 8 to 70%.

[0078] In the process of forming a laminate having the first region 51, a second region 52 having an ink coverage of 100% or more may be formed together with the first region 51. By forming the second region 52, the pressure difference with the first region 51 increases, and air bubbles in the solventless adhesive can be sufficiently dispersed.

[0079] The aging to obtain the first adhesive layer S1 and the second adhesive layer S2 may be performed simultaneously after both the first adhesive composition and the second adhesive composition are applied. In this manner, a laminate 100 can be produced that includes, in this order, the base film 10, the printed layer 50, the first adhesive layer S1, the metal layer 40, the second adhesive layer S2, and the sealant film 20. The laminates according to each of the modifications can also be produced in the same manner as the laminate 100.

[0080] The laminate 100 thus manufactured has the configuration and properties as described above. The explanations regarding the laminate 100 and its modifications also apply to the above-mentioned example of the manufacturing method.

[0081] As shown in FIG. 4, a solventless adhesive composition is prepared by applying a highly viscous adhesive composition 220 to a substrate film 10 or the like using a roll coater 210. Therefore, air bubbles tend to be trapped during application. If the adhesive composition contains air bubbles and is then bonded to a metal layer 40, the adhesion between the metal layer 40 and the adhesive composition decreases, resulting in unevenness due to floating on the metal layer 40. However, by forming a first region 51 with an ink area ratio of 8 to 70%, the printed layer 50 can disperse the air bubbles in the adhesive composition, making the floating due to the air bubbles less noticeable and reducing the occurrence of unevenness when the metal layer 40 is bonded. Therefore, the uniformity of the metallic luster of the laminate 100 can be maintained, resulting in a laminate 100 with excellent design properties.

[0082] For reference, a laminating apparatus using a solvent-based adhesive composition will be described with reference to FIG. 5. In the laminating apparatus 300, a solvent 250 containing an adhesive composition is applied to a substrate film or the like using a roll coater 260. The substrate film coated with the solvent 250 is wound in the direction of the arrow and introduced into a drying section 270. This removes the solvent 250 applied to the substrate film, leaving the adhesive composition contained in the solvent 250 on the substrate film. In this way, laminating apparatuses using solvent-based adhesive compositions use solvents with low viscosity, so the adhesive composition does not trap air bubbles when applied to the film. Therefore, the problem of the design of the laminate 100 being impaired due to the trapping of air bubbles can be said to be a problem specific to the use of solventless adhesive compositions.

[0083] The laminate 100 uses a solvent-free adhesive composition, which can sufficiently reduce the environmental impact. Furthermore, even though such a solvent-free adhesive composition is used, the occurrence of unevenness on the metal layer 40 is reduced and the uniformity of the metallic luster can be sufficiently maintained, resulting in excellent design. Such a laminate 100 is suitable for use as a packaging material. The laminate 100 may be used as a packaging material to produce packaging bags and packages.

[0084] <Packaging bags and packaging> FIG. 6 is a plan view showing an example of a packaging bag and a package formed using the above-described laminate. The packaging bag 150 is formed by bonding the sealant films 20 of a pair of laminates 100 together. The surface facing the base film 10 forms the outer surface of the packaging bag 150. The packaging bag 150 includes a sealed portion 101 formed by bonding the peripheral edges of a pair of film-like, approximately rectangular laminates 100 together, and a storage portion 102 formed between the pair of laminates 100 by the sealed portion 101. That is, the side edges, bottom edge, and top edge of the packaging bag 150 are sealed by the sealed portion 101. The packaging bag 150 includes the storage portion 102 in which the packaged item (e.g., food) is stored in a non-sealed portion (sheet portion) surrounded by the sealed portion 101. The sealed portion 101 at the bottom edge may be sealed after the packaged item is filled in the storage portion 102. The sealed portion 101 is formed by heat-sealing the sealant films 20 together.

[0085] It is not essential that the pair of packaging materials that make up the packaging bag 150 have the same layer structure, and for example, the pair of packaging materials may be made up of laminates having different layer structures.

[0086] The packaging bag 150 may be provided with opening means 120 for making it easier to open. The opening means has a pair of easy-open processed portions 124 consisting of V-shaped notches formed in the sealed portion 101 at the side edge, and a half-cut line 121 between the pair of easy-open processed portions 124 that serves as a cutting path. The half-cut line 121 can be formed using a laser. The easy-open processed portions 124 are not limited to V-shaped notches, and may be U-shaped or I-shaped notches, or may be a group of scars.

[0087] The packaging bag 150 includes the laminate 100, which reduces unevenness on the metal layer 40 and maintains metallic luster, resulting in excellent design. Such a packaging bag 150 can be suitably used as a package. Furthermore, the packaging bag 150 uses the laminate 100 with a solvent-free adhesive, which reduces the environmental impact.

[0088] The packaging body 160 includes a packaging bag 150 and an object to be contained in the container 102 of the packaging bag 150. The object to be contained is not particularly limited and may be a solid, a liquid, or a mixture thereof. Examples of the object to be contained include food, beverages, medicines, electronic devices, etc. Because the packaging body 160 includes the packaging bag 150 having the laminate 100, unevenness on the metal layer 40 is reduced, metallic luster is maintained, and the design is excellent. Furthermore, because the packaging body 160 uses the laminate 100 with a solvent-free adhesive, the environmental impact can be reduced.

[0089] <Method of manufacturing packaging bag and packaging body> The procedure for manufacturing a packaging bag 150 and a package 160 using the laminate 100 is described below. A pair of laminates 100 cut to a predetermined shape is prepared as packaging materials. The sealant films 20 provided on one side of each laminate 100 are placed opposite each other, and the sealant films 20 are bonded together. This forms sealed portions 101 at the top and side edges, and forms an unsealed portion surrounded by the sealed portions 101 in a U-shape. In this way, a packaging bag 155 is obtained in which only the top edge (or only the bottom edge) is unsealed, as shown in FIG. 7. In some examples, the packaging bag of this embodiment may have some edges unsealed, as shown in FIG. 7.

[0090] Next, the contents to be packaged are filled from the unsealed upper end (or lower end). After that, the stacks 100 are bonded together at the upper end (or lower end) to form a sealed portion 101 at the upper end (or lower end). In this way, a package 160 including a packaging bag 150 and the contents contained therein can be manufactured.

[0091] The packaging bag 150 and the packaging body 160 are manufactured using the laminate 100. Therefore, the packaging bag 150 and the packaging body 160 can reduce the environmental burden and increase consumer purchasing interest due to their excellent design.

[0092] Although several examples have been described above, this embodiment is not limited to the above examples. The shape of the packaging bag may be, for example, a four-sided bag, a zipper bag, a standing bag, a gusset bag, a two-sided bag, a three-sided bag, a folded bag, or the like.

[0093] The present disclosure includes the following embodiments and modifications thereof. [1] A substrate film, a printing layer, a first adhesive layer, a metal layer, a second adhesive layer, and a sealant film, in this order; the first adhesive layer and the second adhesive layer contain a solventless adhesive composition containing a polyol component and a polyisocyanate component, a cured product thereof, or a mixture thereof; A laminate having a first region with an ink area ratio of 8 to 70%. [2] A primer layer is provided between the base film and the printing layer, The laminate according to [1], wherein the printed layer contains an electrostatic ink composition. [3] The laminate according to [1] or [2], wherein the metal layer contains aluminum foil. [4] The laminate according to any one of [1] to [3], which has an ink coverage of 500% or less. [5] The laminate according to any one of [1] to [4], which has a second region with an ink coverage of 100% or more. [6] The laminate according to any one of [1] to [5], wherein the polyisocyanate component contains a derivative of hexamethylene diisocyanate. [7] The laminate according to [6], wherein the polyisocyanate component further contains a polyisocyanate different from the derivative of hexamethylene diisocyanate. [8] The laminate according to [6], wherein the derivative of hexamethylene diisocyanate includes a bifunctional derivative of hexamethylene diisocyanate and a trifunctional derivative of hexamethylene diisocyanate. [9] The laminate according to [8], wherein the content of the trifunctional derivative is higher than the content of the bifunctional derivative.

[10] The laminate according to any one of [1] to [9], wherein the mass ratio of the polyisocyanate component to the polyol component is 1 or more.

[11] The laminate according to any one of [1] to

[10] , wherein the polyol component contains a polyether polyol.

[12] The laminate according to any one of [1] to

[11] , wherein the adhesive composition contains a surface modifier.

[13] forming a printing layer on one side of a substrate film; a step of adhering the printed layer and the metal layer using a solventless first adhesive composition containing a polyisocyanate component and a polyol component; a step of adhering the metal layer and a substrate including a sealant film using a solventless second adhesive composition including a polyisocyanate component and a polyol component; and curing or semi-curing the first adhesive composition and the second adhesive composition to form a first adhesive layer and a second adhesive layer, thereby forming a laminate having a first region with an ink area ratio of 8 to 70%.

[14] A step of forming a primer layer on the one side of the base film before the step of forming the printing layer, The method for producing a laminate according to

[13] , wherein the printed layer contains an electrostatic ink composition.

[15] The method for producing a laminate according to

[13] or

[14] , wherein the metal layer contains aluminum foil.

[16] The method for producing a laminate according to any one of

[13] to

[15] , wherein the ink coverage is 500% or less.

[17] A method for manufacturing a laminate according to any one of

[13] to

[16] , wherein in the step of forming the laminate, the laminate is formed to have a second region having an ink coverage of 100% or more together with the first region.

[18] The method for producing a laminate according to any one of

[13] to

[17] , wherein the polyisocyanate component contains a derivative of hexamethylene diisocyanate.

[19] A packaging bag formed by heat-sealing the sealant films in the laminate according to any one of [1] to

[12] above.

[20] A packaging body comprising the packaging bag described in

[19] above and an item to be contained in the storage section of the packaging bag. [Example]

[0094] The present disclosure will be described in more detail with reference to examples and comparative examples, but the present disclosure is not limited to the following examples.

[0095] Example 1 [Laminate fabrication] A commercially available polyethylene terephthalate film (PET film, thickness: 12 μm) was prepared as a substrate film. An aqueous primer resin (a resin containing polyethyleneimine, manufactured by Michelman, product name: DP050) was applied to one side of this PET film to form a primer layer. At this time, the amount of aqueous polyethyleneimine applied was 0.10 to 0.18 g / m 2 The water-based primer resin was applied to the PET film so that the

[0096] An electrostatic ink composition was applied to the surface of the primer layer using a digital printing machine (HP Indigo 20000 label and packaging digital printing machine) to form a printed layer. W (white) was used as the ink composition. The ink coverage was adjusted to form a printed layer with an ink area coverage of 8% per 3 mm square. The ink area coverage was determined using the following procedure. The main surface of the printed substrate film was observed with an optical microscope, and halftone dots within a 3 mm square observation area were extracted, and the total area of ​​the halftone dots was measured using automatic area measurement. The ratio of the total area of ​​the halftone dots to the observation area was calculated. The ink area coverages determined in this way were as shown in Table 1. Halftone dots within the observation area were extracted using the automatic area measurement function of an optical microscope (Keyence Corporation, model number: VHX-6000).

[0097] As polyisocyanate components, a derivative of diphenylmethane isocyanate (MDI) (MDI derivative, manufactured by Mitsui Chemicals, Inc.), a derivative of hexamethylene diisocyanate (HDI derivative I, manufactured by Mitsui Chemicals, Inc.), and a derivative of hexamethylene diisocyanate (HDI derivative II, manufactured by Mitsui Chemicals, Inc.) were prepared. HDI derivative I contained a bifunctional derivative of hexamethylene diisocyanate. HDI derivative II contained a trifunctional derivative of hexamethylene diisocyanate. The MDI derivative, HDI derivative I, and HDI derivative II were blended in a mass ratio of MDI derivative:HDI derivative I:HDI derivative II = 100:14:28 to prepare a polyisocyanate component.

[0098] A polyether polyol (manufactured by Mitsui Chemicals, Inc., product name: XRN-21B) was prepared as the polyol component. The polyol component and the polyisocyanate component were blended so that the mass ratio of the polyol component to the polyisocyanate component was 142 / 65 (≒2.18), and a surface modifier was further added to prepare an adhesive composition. This adhesive composition was heated to approximately 40°C and applied to the primer layer and the printing layer using a roll coater to form a first coating film with a predetermined thickness. The amount of adhesive composition applied was approximately 2.0 g / m 2 This first coating film and an aluminum foil (manufactured by Luoyang Wanji Aluminum Processing Co., Ltd., product number: 8079, thickness: 7 μm) serving as a metal layer were overlapped so as to face each other, and the printed layer on the base film and the aluminum foil were bonded via the first coating film (adhesive composition) using a nip roll.

[0099] Next, the adhesive composition was similarly applied to the surface of the aluminum foil (the surface opposite to the substrate film side) to form a second coating film having a predetermined thickness. The amount of the adhesive composition applied was about 2.0 g / m 2 A commercially available low-density polyethylene film (LDPE film, thickness: 60 μm) was placed facing the second coating film as a sealant film, and the aluminum foil and the sealant film were bonded together via the second coating film (adhesive composition) using a nip roll.

[0100] The adhesive compositions of the first and second coating films were then cured or semi-cured by aging at 45°C for two days. In this way, a laminate was obtained having, in this order, a PET film, a primer layer, a printed layer, a first adhesive layer, an aluminum foil, a second adhesive layer, and an LDPE film. The size of the produced laminate was 18cm long x 12cm wide.

[0101] [Evaluation of Unevenness] The surface of the fabricated laminate was observed and photographed under an optical microscope at 100x magnification. The photograph is shown in Figure 8(a). The photograph was binarized using image analysis software (ImageJ Fiji). The image after binarization is shown in Figure 8(b). In Figure 8(b), the area of ​​the white portion shown by the binarization was calculated as the area of ​​unevenness by automatic area measurement. The results are shown in Table 1.

[0102] [Appearance evaluation] The surface of the produced laminate was visually observed to evaluate whether its appearance was close to the metallic luster of aluminum foil. The evaluation was conducted on a four-point scale according to the following criteria. The results are shown in Table 1. A: Has a metallic luster equivalent to that of aluminum foil. B: Looks a little whitish, but has a metallic luster similar to aluminum foil. C: It is possible to determine that white printing has been performed, but the metallic luster of the aluminum foil remains. D: It can be determined that white printing has been performed, and the metallic luster of the aluminum foil cannot be confirmed.

[0103] Example 2 A laminate was produced using the same procedures as in Example 1, except that the printed layer was formed so that the ink coverage per 3 mm square area was 10%. Evaluation of unevenness and metallic gloss were performed using the same procedures as in Example 1. The results are shown in Table 1. Figure 9(a) shows a photograph of the surface of the laminate, and Figure 9(b) shows a binarized photograph.

[0104] Example 3 A laminate was produced using the same procedures as in Example 1, except that the printed layer was formed so that the ink coverage per 3 mm square area was 16%. Evaluation of unevenness and metallic gloss were performed using the same procedures as in Example 1. The results are shown in Table 1. Figure 10(a) shows a photograph of the surface of the laminate, and Figure 10(b) shows a binarized photograph.

[0105] Example 4 A laminate was produced using the same procedures as in Example 1, except that the printed layer was formed so that the ink coverage per 3 mm square area was 20%. Evaluation of unevenness and metallic gloss were performed using the same procedures as in Example 1. The results are shown in Table 1. Figure 11(a) shows a photograph of the surface of the laminate, and Figure 11(b) shows a binarized photograph.

[0106] Example 5 A laminate was produced in the same manner as in Example 1, except that the printed layer was formed so that the ink coverage per 3 mm square area was 35%. Evaluation of unevenness and metallic gloss were carried out in the same manner as in Example 1. The results are shown in Table 1.

[0107] Example 6 A laminate was produced in the same manner as in Example 1, except that the printed layer was formed so that the ink coverage per 3 mm square area was 70%. Evaluation of unevenness and metallic gloss were carried out in the same manner as in Example 1. The results are shown in Table 1.

[0108] (Comparative Example 1) A laminate was produced using the same procedures as in Example 1, except that no printed layer was formed. That is, in Comparative Example 1, the ink area ratio was 0%. Evaluation of unevenness and evaluation of metallic gloss were carried out using the same procedures as in Example 1. The results are shown in Table 1. Also, Fig. 12(a) shows a photograph of the surface of the laminate, and Fig. 12(b) shows a binarized photograph.

[0109] (Comparative Example 2) A laminate was produced in the same manner as in Example 1, except that the printed layer was formed so that the ink coverage per 3 mm square area was 80%. Evaluation of unevenness and metallic gloss were carried out in the same manner as in Example 1. The results are shown in Table 1.

[0110] [Table 1]

[0111] As shown in Table 1, it was confirmed that as the ink area ratio of the printed layer decreases, the appearance becomes closer to the metallic luster of aluminum foil, but unevenness increases. On the other hand, it was confirmed that as the ink area ratio increases, the air bubbles contained in the solvent-free adhesive composition disperse, reducing unevenness. However, in Comparative Example 2, where the ink area ratio was 80%, it was confirmed that the metallic luster of the appearance disappeared. In Example 4, where the ink area ratio was 20%, as shown in Figure 9(b), no unevenness was observed, and the appearance was confirmed to have a metallic luster equivalent to that of aluminum foil. Therefore, it was shown that by adjusting the ink area ratio, it is possible to obtain a laminate with excellent design, which suppresses the occurrence of unevenness and maintains metallic luster, even when using a solvent-free adhesive composition. [Industrial Applicability]

[0112] According to the present disclosure, it is possible to provide a laminate that has excellent design properties while using a solventless adhesive composition, and a method for producing the same. It is also possible to provide a packaging bag and a packaging body that include such a laminate. [Explanation of symbols]

[0113] 10...base film, 20...sealant film, 40...metal layer, S1...first adhesive layer, S2...second adhesive layer, 50...printed layer, 55...printed surface, 100...laminated body, 51...first region, 52...second region, 150, 155...packaging bag, 101...sealed portion, 102...storage portion, 120...opening means, 121...half-cut line, 124...easy-open processing portion, 160...packaging body, 200, 300...laminating device, 201...film roll, 210, 260...roll coater, 220...adhesive composition, first adhesive composition, second adhesive composition, 230...nip roll, 240...raw fabric roll, 250...solvent, 270...drying portion.

Claims

1. a substrate film, a printing layer, a first adhesive layer, a metal layer, a second adhesive layer, and a sealant film in this order; the first adhesive layer and the second adhesive layer contain a solventless adhesive composition containing a polyol component and a polyisocyanate component, a cured product thereof, or a mixture thereof; A laminate having a first region with an ink coverage of 8 to 70%.

2. a primer layer is provided between the base film and the printing layer; The laminate of claim 1 , wherein the print layer comprises an electrostatic ink composition.

3. The laminate according to claim 1 or 2, wherein the metal layer comprises aluminum foil.

4. 3. The laminate according to claim 1, wherein the ink coverage is 500% or less.

5. The laminate according to claim 1 or 2, which has a second region having an ink coverage of 100% or more.

6. The laminate of claim 1 or 2, wherein the polyisocyanate component comprises a derivative of hexamethylene diisocyanate.

7. The laminate of claim 6 , wherein the polyisocyanate component further comprises a polyisocyanate different from the derivative of hexamethylene diisocyanate.

8. The laminate according to claim 6 , wherein the derivative of hexamethylene diisocyanate includes a bifunctional derivative of hexamethylene diisocyanate and a trifunctional derivative of hexamethylene diisocyanate.

9. The laminate according to claim 8 , wherein the content of the trifunctional derivative is higher than the content of the bifunctional derivative.

10. The laminate according to claim 1 or 2, wherein a mass ratio of the polyisocyanate component to the polyol component is 1 or more.

11. The laminate according to claim 1 or 2, wherein the polyol component comprises a polyether polyol.

12. The laminate of claim 1 or 2, wherein the adhesive composition comprises a surface modifier.

13. forming a printing layer on one side of a substrate film; a step of adhering the printed layer and the metal layer using a solventless first adhesive composition containing a polyisocyanate component and a polyol component; a step of adhering the metal layer and a substrate including a sealant film using a solventless second adhesive composition including a polyisocyanate component and a polyol component; and curing or semi-curing the first adhesive composition and the second adhesive composition to form a first adhesive layer and a second adhesive layer, thereby forming a laminate having a first region with an ink area ratio of 8 to 70%.

14. a step of forming a primer layer on the one surface side of the base film before the step of forming the printing layer, The method for producing a laminate according to claim 13 , wherein the print layer comprises an electrostatic ink composition.

15. The method for producing a laminate according to claim 13 or 14, wherein the metal layer comprises aluminum foil.

16. The method for producing a laminate according to claim 13 or 14, wherein the ink coverage is 500% or less.

17. The method for manufacturing a laminate according to claim 13 or 14, wherein in the step of forming the laminate, the laminate is formed to have, together with the first region, a second region having an ink coverage of 100% or more.

18. The method for producing a laminate according to claim 13 or 14, wherein the polyisocyanate component includes a derivative of hexamethylene diisocyanate.

19. A packaging bag formed by heat-sealing the sealant films in the laminate according to claim 1 or 2.

20. A package comprising the packaging bag according to claim 19 and an item accommodated in the accommodation portion of the packaging bag.

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