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

Abstract

To suppress appearance defects that occur when manufacturing a laminate including a metal deposition layer using a solvent-free adhesive.SOLUTION: A method for manufacturing a laminate 100 including a metal deposition layer 12 using a solvent-free adhesive, comprises: a preparation step of coating the metal deposition layer 12 of a metal deposition film 13 with a resin coat layer 15 containing a urethane resin and a cellulose ester resin to obtain a first film 10; and a laminating step of laminating the first film 10 and a second film 20 using a urethane-based solvent-free adhesive. In the laminating step, the first film 10 and the second film 20 are laminated such that the resin coat layer 15 is in contact with a layer S'1 formed of the urethane-based solvent-free adhesive.SELECTED DRAWING: Figure 1

Description

Technical Field

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

Background Art

[0002] As part of environmental measures, packaging bags (for example, flexible packaging bags) using plastic films have become widespread. In many cases, flexible packaging bags have a laminated structure in which two or more films are bonded together using an adhesive in order to improve their required performance (for example, strength, water resistance, moisture permeability resistance, gas barrier properties against gases such as oxygen, heat resistance, etc.).

[0003] In recent years, from the viewpoint of reducing the environmental impact, the use of solventless adhesives as adhesives for forming the above laminated structure has been studied. However, when manufacturing a laminated body including a metal vapor deposition layer using a solventless adhesive, there is a problem that appearance defects (for example, appearance defects called orange peel) are likely to occur particularly at the adhesive interface between the metal vapor deposition layer and other layers due to the entrapment of air bubbles.

[0004] On the other hand, for example, in Patent Document 1, it has been proposed to solve the problem of the above appearance defects by using a specific solventless adhesive composition.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] However, even with the method of Patent Document 1 described above, appearance defects may occur in the laminated body, and there is still room for improvement in the manufacturing method of the laminated body using a solventless adhesive.

[0007] Therefore, one aspect of the present disclosure aims to suppress appearance defects that occur when manufacturing a laminate including a metal vapor deposition layer using a solventless adhesive. Another aspect of the present disclosure aims to provide a laminate in which the above appearance defects are suppressed. **Means for Solving the Problems**

[0008] The inventors of the present invention have found that poor wettability and adhesion between the solventless adhesive and the metal vapor deposition layer are one of the causes of the above appearance defects. That is, in the coating of the solventless adhesive, roughness occurs on the coated surface. When the metal vapor deposition layer is laminated on the coated surface having such roughness, the wettability and adhesion between the coating film and the metal vapor deposition layer are poor, and due to the high cohesive force of the coating film (adhesive) itself, the roughness of the coated surface is not eliminated, and bubbles remain trapped. As a result, it has been found that appearance defects occur. As a result of intensive studies based on such findings, it has been found that by providing a specific resin coat layer on the metal vapor deposition layer, it is possible to improve appearance defects caused by poor wettability and adhesion between the solventless adhesive and the metal vapor deposition layer, leading to the present disclosure.

[0009] Some aspects of the present disclosure provide the following [1] to

[10] .

[0010] [1] A laminate comprising a first film, a second film, and a first adhesive layer that adheres the first film and the second film, wherein the first adhesive layer is formed using a urethane-based solventless adhesive, wherein the first film includes a metal vapor deposition layer and a resin coat layer that covers the metal vapor deposition layer and forms a contact surface with the first adhesive layer, wherein the resin coat layer includes a urethane-based resin and a cellulose ester-based resin.

[0011] [2] The laminate according to [1], wherein the resin coat layer contains a filler.

[0012] [3] The laminate according to [1] or [2], wherein the metal vapor deposition layer is an aluminum vapor deposition layer.

[0013] [4] The laminate according to any one of [1] to [3], wherein the base material of the first film is a polypropylene film or a polyethylene terephthalate film.

[0014] [5] The laminate according to any one of [1] to [4], wherein the second film includes a printing layer.

[0015] [6] The laminate according to any one of [1] to [5], further comprising a third film laminated via a second adhesive layer on the side opposite to the first adhesive layer side of the first film or the second film.

[0016] [7] The laminate according to any one of [1] to [6], including a sealant layer.

[0017] [8] A packaging material including the laminate according to any one of [1] to [7].

[0018] [9] A packaging bag formed by bag-making the packaging material according to [8].

[0019]

[10] A method for manufacturing a laminate including a metal vapor deposition layer, using a solventless adhesive, the method comprising: A preparation step of coating the metal vapor deposition layer of a metal vapor deposition film with a resin coat layer containing a urethane-based resin and a cellulose ester-based resin to obtain a first film; and A lamination step of laminating the first film and the second film using a urethane-based solventless adhesive, In the lamination step, the first film and the second film are laminated such that the resin coat layer and the layer composed of the urethane-based solventless adhesive are in contact with each other. [Advantages of the Invention]

[0020] According to one aspect of the present disclosure, it is possible to suppress appearance defects that occur when manufacturing a laminate including a metal vapor deposition layer using a solventless adhesive. Further, according to another aspect of the present disclosure, an object is to provide a laminate in which the above appearance defects are suppressed.

Brief Description of the Drawings

[0021]

Figure 1

Figure 2

Embodiments for Carrying Out the Invention

[0022] In this specification, a numerical range indicated using “~” indicates a range including the numerical values described before and after “~” as the minimum value and the maximum value, respectively. Further, unless specifically specified otherwise, the units of the numerical values described before and after “~” are the same. Also, in the numerical ranges described in this specification, the upper limit value or the lower limit value of the numerical range may be replaced with the value shown in the examples. Further, the individually described upper limit value and lower limit value can be arbitrarily combined. Also, “A or B” means that either one of A and B may be included, or both may be included. Further, in this specification, the “solventless adhesive” refers to an adhesive that substantially does not contain a solvent (organic solvent and water) (the solvent content is 0.5 mass% or less).

[0023] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings as appropriate. However, the present invention is not limited to the following embodiments. In the drawings, the same or corresponding parts are denoted by the same reference numerals, and redundant descriptions are omitted. The dimensional ratios in the drawings are not limited to the illustrated ratios.

[0024] <Laminate and Method for Manufacturing the Same> FIG. 1 is a schematic cross-sectional view showing a method for manufacturing a laminate according to an embodiment and the laminate obtained thereby. The method for manufacturing a laminate according to an embodiment is a method for manufacturing a laminate including a metal vapor deposition layer using a solventless adhesive. The metal vapor deposition layer 12 of the metal vapor deposition film 13 is coated with a resin coat layer 15 containing a urethane-based resin and a cellulose ester-based resin to obtain a first film 10 (see (a) of FIG. 1).) And a lamination step of laminating the first film 10 and the second film 20 using a urethane-based solventless adhesive (see (b) and (c) of FIG. 1).), In the lamination step, the first film 10 and the second film 20 are laminated so that the resin coat layer 15 and the layer S'1 made of the urethane-based solventless adhesive are in contact with each other.

[0025] According to the above method, it is possible to suppress appearance defects that occur when manufacturing a laminate including a metal vapor deposition layer using a solventless adhesive. Therefore, the laminate 100 in FIG. 1(c) obtained by the above method can be said to be a laminate with suppressed appearance defects. First, the laminate 100 will be described below.

[0026] The laminate 100 shown in FIG. 1(c) includes a first film 10, a second film 20, and an adhesive layer S1 (first adhesive layer) that adheres 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.

[0027] (Adhesive layer) The adhesive layer S1 is a layer formed using a urethane-based solventless adhesive. For example, it is 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 a urethane-based solventless adhesive. It should be noted that the fact that the adhesive layer S1 is a layer formed using a solventless adhesive rather than a solvent-based adhesive can be confirmed by analysis using, for example, Fourier transform infrared spectroscopy.

[0028] The urethane-based solventless adhesive contains, for example, polyols such as polyester polyol, polyether polyol, and acrylic polyol, and polyisocyanates such as aromatic polyisocyanate and aliphatic polyisocyanate. The urethane-based solventless adhesive may be a one-component curing type adhesive in which the polyol and the polyisocyanate are premixed, or may be a two-component curing type adhesive containing a main agent containing the polyol and a curing agent containing the polyisocyanate. The two-component curing type adhesive is used by mixing the main agent and the curing agent. In any of the adhesives, each component reacts (for example, the hydroxyl group of the polyol reacts with the isocyanate group of the polyisocyanate) and cures by heating or the like.

[0029] The equivalent ratio (NCO group / OH group molar ratio) of the isocyanate group (for example, the isocyanate group possessed by the polyisocyanate) to the hydroxyl group (for example, the hydroxyl group possessed by the polyol) in the urethane-based solventless adhesive can be, for example, 0.5 to 5.

[0030] The thickness of the adhesive layer S1 is, for example, 0.3 to 5.0 μm, may be 1.0 to 2.5 μm, or may be 1.2 to 2.0 μm. The basis weight of the adhesive layer S1 is, for example, 0.6 to 2.5 g / m 2 and may be.

[0031] (First Film) The first film 10 includes a base material 11 (first base material), a metal vapor deposition layer 12, and a resin coating layer 15 in this order. At least a part of the surface of the metal vapor deposition layer 12 is covered with the resin coating layer 15, and the resin coating layer 15 forms a contact surface with the adhesive layer S1 (that is, the surface of the first film 10 that contacts the adhesive layer S1). The thickness of the first film is, for example, 10 to 60 μm.

[0032] [Base Material] The base material 11 is, for example, a resin film. Examples of the resin material 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 consist of only one kind of resin or may contain two or more kinds of resins. The resin film may be a composite film formed by laminating two or more films formed of the above resin material. The resin film may contain materials other than resin (such as additives), but the content of resin in the resin film is 98% by mass or more. The resin film may be a stretched resin film or an unstretched resin film. The resin film may be a laminate of a stretched resin film and an unstretched resin film.

[0033] From the viewpoint of adhesion to the metal vapor deposition layer, the base material 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).

[0034] As shown in FIG. 1, when the base material 11 is disposed on the outermost side of the laminate, the base material 11 may have sealability for sealing the laminate 100 in a bag shape. That is, the base material 11 may be a sealant layer. Examples of the sealant layer include a layer containing an unstretched resin film (such as an unstretched polypropylene film).

[0035] On the surface of the base material 11 (the surface on the side of the metal vapor deposition layer), various treatments such as corona treatment, plasma treatment, and ozone treatment may be performed as a pretreatment to improve the adhesion to the metal vapor deposition layer.

[0036] The thickness of the base material 11 can be appropriately changed according to the required characteristics of the application (for example, various resistances and processabilities required for packaging materials, etc.), and can be, for example, 10 to 60 μm.

[0037] [Metal vapor deposition layer] The metal vapor deposition layer 12 is a layer formed by vapor deposition of a metal material. The metal vapor deposition layer 12 is preferably colored and opaque, and more preferably has light blocking properties (light shielding properties) and barrier properties (gas barrier properties) against gases such as oxygen gas and water vapor gas. That is, the metal vapor deposition layer 12 may be provided as a barrier layer.

[0038] As the metal material, a material capable of imparting the above properties is preferably used. Examples of such metal materials include materials containing metals such as aluminum, magnesium, sodium, titanium, chromium, zinc, tin, gold, sodium, zirconium, and indium. Among them, for use as a packaging bag, it is preferable that the metal vapor deposition layer 12 is an aluminum vapor deposition layer formed by vapor deposition of aluminum.

[0039] The thickness of the metal vapor deposition layer 12 is preferably in the range of 0.01 to 0.1 μm.

[0040] [Resin coating layer 15] The resin coating layer 15 contains a urethane-based resin and a cellulose ester-based resin. In other words, the resin coating layer 15 is composed of a resin composition containing a urethane-based resin and a cellulose ester-based resin. The resin coating layer 15 exhibits high affinity for solventless adhesives by containing a urethane-based resin and a cellulose ester-based resin.

[0041] Examples of the urethane-based resin include polyether-based, ester-based, carbonate-based, acrylic-based, and aliphatic-based polyurethane resins. The molecular structure of the polyurethane resin may contain a urea bond or an imide bond.

[0042] Examples of commercially available urethane resins include solvent-based coating liquids such as the Sample IB series manufactured by Sanyo Chemical Industries, Ltd., the Takelac E series manufactured by Mitsui Chemicals, Inc., the Barnoc series manufactured by DIC Corporation, and the Byron UR series manufactured by Toyobo Co., Ltd.

[0043] Examples of cellulose ester resins include cellulose acetate propionate (CAP), cellulose acetate butyrate (CAB), and nitrocellulose.

[0044] Examples of commercially available cellulose esters include the CAB and CAP series of Eastman Chemical Company.

[0045] The mixing ratio of the urethane resin and the cellulose ester resin (amount of urethane resin: amount of cellulose ester resin) is not particularly limited, but from the viewpoint of good coating applicability and adhesion, it is preferably 95:5 to 50:50 by mass ratio.

[0046] The content of the urethane resin may be 50% by mass or more, may be 75% by mass or more, or may be 90% by mass or more based on the total mass of the resin coat layer (total mass of the resin composition) from the viewpoint of adhesion to the metal vapor deposition layer. The content of the urethane resin may be 99% by mass or less, may be 97% by mass or less, or may be 95% by mass or less based on the total mass of the resin coat layer (total mass of the resin composition) from the viewpoint of adhesion to the adhesive layer. From these viewpoints, the content of the urethane resin may be 50 to 99% by mass, or may be 50 to 95% by mass based on the total mass of the resin coat layer (total mass of the resin composition).

[0047] From the perspective of heat resistance, the content of the cellulose ester resin may be 1% by mass or more, may be 3% by mass or more, or may be 5% by mass or more, based on the total mass of the resin coat layer (the total mass of the resin composition). From the perspective of coating applicability, the content of the cellulose ester resin may be 50% by mass or less, may be 25% by mass or less, or may be 10% by mass or less, based on the total mass of the resin coat layer (the total mass of the resin composition). From these perspectives, the content of the cellulose ester resin may be 1 to 50% by mass, or may be 5 to 50% by mass, based on the total mass of the resin coat layer (the total mass of the resin composition).

[0048] In addition to the above resin, the resin coat layer 15 preferably contains a filler. The type of the filler is not particularly limited, and it may be any of an organic filler, an inorganic filler, and an organic-inorganic hybrid type filler, and one type may be used alone, or two or more types may be used in combination.

[0049] Examples of the inorganic filler include fillers composed of inorganic materials such as aluminum silicate, magnesium silicate, calcium silicate, kaolin, aluminosilicate, halloysite, natural silica, synthetic silica, synthetic zeolite, boehmite, aluminum oxide, iron oxide, magnesium oxide, calcium oxide, zinc oxide, titanium oxide, chromium oxide, zirconium oxide, calcium carbonate, magnesium carbonate, silicon nitride, silicon carbide, calcium titanate, barium titanate, magnesium pyrophosphate, and glass.

[0050] Examples of the organic filler include fillers composed of organic materials such as polyolefin resins such as polyethylene and polypropylene, styrene resins, epoxy resins, melamine resins, acrylic resins, phenolic resins, polyimide resins, polyamide resins, polyester resins, polyacetal resins, polyurethane resins, vinyl acetate copolymer resins, and copolymers of these resins.

[0051] Examples of the organic-inorganic hybrid filler include those obtained by hybridizing silica particles with an acrylic resin.

[0052] The filler may be spherical or fibrous. For example, the filler may be glass fiber.

[0053] The filler is preferably exposed on the surface of the resin coat layer 15 (the surface on the side in contact with the adhesive layer S1). Conventionally, it is common to make the surface in contact with the solvent-free adhesive a smooth surface. However, in the method of this embodiment, by exposing the filler on the surface of the resin coat layer 15, appearance defects can be further suppressed. This is presumably because the flow of the adhesive is suppressed by the pinning effect of the filler.

[0054] The average particle diameter of the filler is appropriately set according to the thickness of the resin coat layer. From the viewpoint of facilitating the exposure of the filler on the surface of the resin coat layer, 0.1 to 3 μm is preferable. From the same viewpoint, the average particle diameter of the filler is preferably 1.1 to 1.3 times the thickness of the resin coat layer 15. Here, the average particle diameter means the D50 value measured by the laser diffraction / scattering method in accordance with JIS Z8825.

[0055] From the viewpoint of the coating appearance, the content of the filler may be 0.1% by mass or more, 0.3% by mass or more, or 0.5% by mass or more based on the total mass of the resin coat layer (the total mass of the resin composition). From the viewpoint of the transparency of the coating film, the content of the filler may be 5% by mass or less, 4% by mass or less, or 3% by mass or less based on the total mass of the resin coat layer (the total mass of the resin composition). From these viewpoints, the content of the filler may be 0.1 to 5% by mass based on the total mass of the resin coat layer (the total mass of the resin composition).

[0056] The resin coating layer 15 may contain other components other than urethane resins, cellulose ester resins, and fillers as long as the effects of the present invention are not impaired. For example, the resin coating layer 15 may contain other resins such as vinyl chloride-vinyl acetate copolymer resins, polyamide resins, polyester resins, acrylic resins, and epoxy resins. The resin coating layer 15 may contain resin additives (such as stabilizers) commonly used in the art.

[0057] The thickness of the resin coating layer 15 may be, for example, 0.1 to 2 μm. The basis weight of the resin coating layer may be, for example, 0.1 to 2.3 g / m 2 and may be.

[0058] (Second film) The second film 20 includes a base material 21 (second base material) and a printing layer 22 provided on the base material 21. In the second film 20, the printing layer 22 forms a contact surface with the adhesive layer S1 (that is, 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.

[0059] [Base material] Examples of the base material 21 are the same as those of the base material 11 (first base material) constituting the first film 10. The base material 21 may have transparency so that a pattern by the printing layer can be displayed.

[0060] The thickness of the base material 21 is, for example, 3 to 150 μm, and may be 5 to 60 μm.

[0061] [Printing layer] The printing layer 22 is an ink layer formed of one or more inks. As the ink, for example, general gravure ink, flexographic ink, offset ink, digital printing ink, etc. can be used. When the ink is an oil-based gravure ink, the ink may contain, as a binder resin, a mixture of a urethane resin and a vinyl chloride-vinyl acetate copolymer resin, etc. 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 coloring pigment, called a color ink, or may be a colorless ink not containing a coloring pigment. As the ink, for example, vegetable oil ink, biomass ink, etc. can also be used. The ink may be an aqueous ink.

[0062] The thickness of the printing layer 22 may be, for example, 0.2 to 8 μm.

[0063] Although not shown, the contact surface with the adhesive layer S1 formed by the printing layer 22 may have steps (concavities and convexities). In the conventional method, appearance defects are likely to occur at such stepped portions, whereas in the method of this embodiment, even when the second film 20 has such steps, appearance defects are less likely to occur.

[0064] The laminate 100 described above is a laminate with suppressed appearance defects. For example, when observing the interface between the resin coat layer 15 and the adhesive layer S1 of the laminate 100, the number of bubbles of 0.5 mm or more confirmed in a range of 10 cm × 10 cm is 9 or less. The number of the above bubbles is preferably 0 to 9, and more preferably 0. Note that the number of bubbles of 0.5 mm or more confirmed in a range of 10 cm × 10 cm being 9 or less means that there is no 10 cm × 10 cm region on the above interface where the number of bubbles of 0.5 mm or more is 10 or more.

[0065] The laminate 100 is suitably used for a packaging material for forming a packaging bag (e.g., a flexible packaging bag) for packaging contents.

[0066] Next, each step in the method for manufacturing the laminate 100 will be described.

[0067] (Preparation Step) In the preparation step, first, a metal vapor deposition film 13 is prepared, and the metal vapor deposition layer 12 of the metal vapor deposition film 13 is coated with a resin coat layer 15 to obtain a first film 10 (see (a) of FIG. 1).

[0068] The metal vapor deposition film 13 is a film including a base material 11 (first base material) and a metal vapor deposition layer 12 provided on the base material 11. On the above-described base material 11, a physical vapor deposition method (PVD (Physical Vapor Deposition) method) such as a vacuum vapor deposition method, a sputtering method, or an ion plating method, or a chemical vapor deposition method (CVD (Chemical Vapor Deposition) method) such as a plasma chemical vapor deposition method, a thermal chemical vapor deposition method, or a photo chemical vapor deposition method. The metal vapor deposition layer 12 can be obtained by forming it by a conventionally known method. As the metal vapor deposition film 13, a known film used for a packaging bag may be used. For example, an aluminum vapor deposition polypropylene film called VM-CPP, an aluminum vapor deposition polyethylene terephthalate (PET) film called VM-PET, or the like may be used.

[0069] The thickness of the metal vapor deposition film 13 can be appropriately changed according to the required characteristics of the application (for example, various resistances and processabilities required for a packaging material), and may be, for example, 10 to 60 μm.

[0070] The resin coating layer 15 can be formed by mixing each component (urethane resin, cellulose ester resin, filler, etc.) serving as a material to prepare a coating agent composition, coating this on the surface of the metal vapor deposition layer 12, and performing a drying treatment as necessary. The coating method may be a known coating method such as a roll coating method, a gravure coating method, a spray coating method, an air knife coating method, a kiss coating method, etc. From the viewpoints of productivity, film thickness uniformity, etc., the gravure coating method is preferable. The coating amount of the coating composition may be adjusted according to the thickness of the target resin coating layer 15 (for example, so that the basis weight after drying falls within the above range).

[0071] (Lamination process) In the lamination process, first, after applying a urethane-based solventless adhesive to the surface of the printing layer 22 side of the second film 20, the first film 10 and the second film 20 are laminated so that the layer (first uncured layer) S'1 made of the urethane-based solventless adhesive and the resin coating layer 15 are in contact with each other (see (b) in FIG. 1). Next, by curing the urethane-based solventless adhesive, the first film 10 and the second film 20 are adhered to each other (see (c) in FIG. 1). Thereby, the above laminate 100 is obtained.

[0072] The application of the adhesive and the lamination (lamination) of the first film 10 and the second film 20 can be performed using a known non-solvent laminator.

[0073] 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 above application temperature) may be, for example, 10 to 1200 mPa·s. Here, the viscosity of the adhesive is the cone-plate viscosity according to JIS K 5600-2-2:2014.

[0074] 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 higher the lamination speed, the more likely appearance defects are to occur. However, in the method of this embodiment, even when the lamination speed is 200 m / min or more (for example, 200 to 400 m / min), a good appearance is likely to be obtained.

[0075] The curing method of the urethane-based solventless adhesive varies depending on the type of the adhesive. For example, when the urethane-based solventless adhesive is a thermosetting adhesive, the urethane-based solventless adhesive may be cured by heating the laminate after lamination.

[0076] As described above, the method for manufacturing a laminate according to an embodiment of the present disclosure and the laminate obtained by the manufacturing method have been described. However, the present disclosure is not limited to the above embodiment.

[0077] For example, the application surface of the urethane-based solventless adhesive in the lamination step is not limited to the above, and the urethane-based solventless adhesive may be applied to the surface on the resin coat layer 15 side of the first film 10.

[0078] Also, for example, the first film 10 and the second film 20 may have other functional layers such as a concealment layer according to the application.

[0079] Also, for example, in order to impart mechanical strength, barrier properties, light resistance, unsealing properties, heat sealability, etc. required for a packaging bag, one or two or more other films other than the first film 10 and the second film 20 may be laminated.

[0080] As an example, as shown in FIG. 2, after applying a second adhesive to the surface of the third film 30, the laminate 100 and the third film 30 are laminated so that the layer (second uncured layer) S'2 made of the second adhesive contacts the base material 11 of the first film 10, thereby obtaining a laminate 200. The laminate 200 thus obtained, in addition to the laminate structure of the laminate 100 described above, further includes 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 (i.e., on the side of the first film 10 opposite to the second film 20) via the second adhesive layer S2. Note that 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 (i.e., on the side of the second film 20 opposite to the first film 10) via the second adhesive layer S2. Also, 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.

[0081] The type of other films such as the third film is not particularly limited. The other film may be, for example, a resin film exemplified by the above 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 base material of the third film or the second film is a sealant layer.

[0082] The adhesive used for laminating other films such as the second adhesive may be a solvent-free adhesive, and may be the urethane-based solvent-free adhesive described above.

[0083] Also, the arrangement of the printing layer 22 in the second film 20 is not limited to the above. Films other than the second film 20 may include the printing layer 22, and the second film 20 may not include the printing layer 22. Also, the laminate may not include the printing layer 22. However, when the laminate includes a printing layer, from the viewpoints of preventing ink scraping due to abrasion and preventing ink transfer when a plurality of laminates are stacked, etc., the printing layer is usually provided on the inner surface of the laminate. From such a viewpoint, the laminate may have, for example, a laminated structure of outer layer / printing layer / adhesive layer / intermediate layer / adhesive layer / inner layer.

[0084] <Packaging material> Another embodiment of the present disclosure is a packaging material (for example, a packaging film) including the laminate of the above embodiment. The packaging material includes, for example, a sealant layer in the outermost layer. A packaging material having such a configuration is suitably used for forming a packaging bag (for example, a flexible packaging bag) for packaging contents. Specifically, for example, a packaging bag can be manufactured by laminating and bag-making the sealant layers of a pair of packaging materials. Also, for example, a packaging bag can be manufactured by folding and bag-making a single packaging material so that the surfaces of the sealant layers face each other. When the laminate of the above embodiment includes a sealant layer, the laminate can be used as the packaging material as it is. When the laminate does not include a sealant layer, a film (sealant film) including a sealant layer can be attached to the laminate to form the packaging material.

[0085] <Packaging bag> Another embodiment of the present disclosure is a packaging bag formed by bag-making 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).

[0086] A flat pouch-shaped packaging bag can be formed, for example, by folding a single piece of packaging material (packaging material including a sealant layer) in half with the sealant layers facing each other and then heat-sealing three sides to form a bag shape, or by overlapping two pieces of packaging material (packaging material including a sealant layer) with the sealant layers facing each other and then heat-sealing four sides to form a bag shape.

[0087] A self-standing packaging bag can be formed, for example, by facing the sealant layers of two pieces of packaging material (packaging material including a sealant layer), inserting a single piece of packaging material (packaging material including a sealant layer) folded in half with the sealant layer facing the outside between these layers so as to stack three pieces of packaging material in total, and then heat-sealing four sides to form a bag shape.

[0088] Examples of the contents packaged in the packaging bag include liquid seasonings, toiletry items, soups, liquid substances such as liquid detergents, solid substances such as boiled foods, and solid-liquid mixtures of liquid substances and solid substances such as curries.

Example

[0089] Hereinafter, the present disclosure will be described based on examples and comparative examples. Note that the present disclosure is not limited to the following examples.

[0090] <Example 1> (Preparation of coating liquid) 50 parts by mass of a urethane resin (Sample IB-972 manufactured by Sanyo Chemical Industries, Ltd., solid content 30% by mass) and 1 part by mass of a cellulose acetate propionate resin (CAP-504-0.2 manufactured by Eastman Chemical Company) were mixed to obtain a mixed resin. The obtained mixed resin was dissolved in a mixed solvent composed of 20 parts by mass of methyl ethyl ketone, 9 parts by mass of isopropyl alcohol, and 20 parts by mass of ethyl acetate to prepare a coating liquid 1 for forming a resin coat layer.

[0091] (Production of the first film) As the metal vapor deposition film, an aluminum vapor deposition polyethylene terephthalate (PET) film "Tetrite EXE" (manufactured by Oike Pack Material Co., Ltd., trade name, thickness 12 μm, metal vapor deposition layer: aluminum vapor deposition layer (thickness 40 nm), base material: PET film (thickness 12 μm)) was prepared, and the coating liquid 1 was coated on the surface of the aluminum vapor deposition layer of the metal vapor deposition film by the gravure coating method. The coating amount of the coating liquid 1 was 0.5 g / m in terms of the mass after drying. 2 Next, the resin coating layer (thickness 0.4 μm) was formed by drying the coating film formed by coating. Thus, a first film having a laminated structure of [PET film / aluminum vapor deposition layer / resin coating layer] was obtained.

[0092] (Production of the second film) On the laminating surface of a biaxially stretched nylon (ONY) film "ONMB-RT" (manufactured by Unitika Ltd., emblem, thickness 15 μm), "Realpha White" manufactured by Toyo Ink Co., Ltd. was printed by gravure printing to form a printing layer (thickness 1.5 μm). Thus, a second film having a laminated structure of [ONY film / printing layer] was obtained.

[0093] (Production of the laminate) As the third film, an unstretched polyethylene film (PE sealant film) "SE620F" (manufactured by Tamapoly Co., Ltd., SE620F, thickness 100 μm) was prepared, and the second film, the first film, and the third film were laminated in this order. For the lamination process, a solvent-free adhesive "TSN-4864A / TSN-4864B3" (manufactured by Toyo Morton Co., Ltd.) mixed at a mass ratio of 100:100 was used. Also, the solvent-free adhesive was applied at an adhesive temperature of 80°C (viscosity approximately 600 mPa·s) and a coating amount of 1.8 g / m using a roll coater. 2Coating was performed at a processing speed of 250 m / min. Subsequently, the solvent-free adhesive was cured by performing an aging treatment at 40°C for 72 hours, and a laminate having a laminated structure of [ONY film / printing layer / solvent-free adhesive layer (first adhesive layer) / resin coat layer / aluminum vapor deposition layer / PET film / solvent-free adhesive layer (second adhesive layer) / PE sealant film] was obtained.

[0094] <Example 2> (Production of the first film) As the metal vapor deposition film, except that an aluminum vapor deposition uniaxially oriented polypropylene (CPP) film "2703" (manufactured by Toray Process Film Co., Ltd., VM-CPP, thickness 25 μm, metal vapor deposition layer: aluminum vapor deposition layer (thickness 50 nm), base material: CPP film (thickness 25 μm)) was used, in the same manner as in Example 1, a first film having a laminated structure of [CPP film / aluminum vapor deposition layer / resin coat layer] was obtained.

[0095] (Production of the second film) On the laminate surface of a PET film "E5102" (manufactured by Toyobo Co., Ltd., Toyobo ester film, thickness 12 μm), "Realpha White" manufactured by Toyo Ink Co., Ltd. was printed by gravure printing to form a printing layer (thickness 1.5 μm). Thereby, a second film having a laminated structure of [PET film / printing layer] was obtained.

[0096] (Production of the laminate) The above second film and the above first film were laminated in the same manner as in Example 1, and then aging treatment was performed in the same manner as in Example 1 to obtain a laminate having a laminated structure of [PET film / printing layer / solvent-free adhesive layer / resin coat layer / aluminum vapor deposition layer / CPP film].

[0097] <Example 3> (Preparation of the coating liquid) Filler "Seahoster KE-P100" (manufactured by Nippon Shokubai Co., Ltd.) with an average particle diameter of 1.0 μm was added to coating liquid 1 to prepare coating liquid 2. The addition amount of the filler was 0.1 part by mass with respect to 100 parts by mass of coating liquid 1.

[0098] A laminate having a laminated structure of [ONY film / printing layer / solventless adhesive layer (first adhesive layer) / resin coat layer / aluminum vapor deposition layer / PET film / solventless adhesive layer (second adhesive layer) / PE sealant film] was produced in the same manner as in Example 1, except that coating liquid 2 was used instead of coating liquid 1 when producing the first film.

[0099] <Example 4> A laminate having a laminated structure of [PET film / printing layer / solventless adhesive layer / resin coat layer / aluminum vapor deposition layer / CPP film] was produced in the same manner as in Example 2, except that coating liquid 2 was used instead of coating liquid 1 when producing the first film.

[0100] <Comparative Example 1> A laminate having a laminated structure of [ONY film / printing layer / solventless adhesive layer (first adhesive layer) / aluminum vapor deposition layer / PET film / solventless adhesive layer (second adhesive layer) / PE sealant film] was produced in the same manner as in Example 1, except that an aluminum vapor-deposited polyethylene terephthalate (PET) film "Tetrite EXE" was used as the first film (i.e., no resin coat layer was provided).

[0101] <Comparative Example 2> A laminate having a laminated structure of [PET film / printing layer / solventless adhesive layer / resin coat layer / aluminum vapor deposition layer / CPP film] was produced in the same manner as in Example 2, except that an aluminum vapor-deposited non-stretched polypropylene (CPP) film "2703" was used as the first film (i.e., no resin coat layer was provided).

[0102] (Comparative Example 3) A resin coat layer was formed on the surface of the printing layer in the second film of Example 1, and this was used as the second film of Comparative Example 3. The resin coat layer was formed in the same manner as in Example 1.

[0103] Next, as the second film, a laminate having a laminated structure of [ONY film / printing layer / resin coat layer / solventless adhesive layer (first adhesive layer) / aluminum vapor deposition layer / PET film / solventless adhesive layer (second adhesive layer) / PE sealant film] was produced in the same manner as in Comparative Example 1, except that the film having the resin coat layer obtained above was used.

[0104] <Evaluation Items> The appearance of the laminate produced in each example was visually observed from the second film side (printing layer side), the number of bubbles having a diameter (maximum diameter) of 0.5 mm or more was confirmed, and evaluation was made according to the following criteria. The observation range was set to 10 cm × 10 cm, and when the evaluation was 3 or more, it was judged to have a good appearance. The results are shown in Table 1. 4: No appearance defects due to bubbles (a pattern like a pebbled skin or a small spotted pattern) were confirmed 3: The number of bubbles was 1 to 9 2: The number of bubbles was 10 to 29 1: The number of bubbles was 30 or more

[0105]

Table 1

Explanation of Symbols

[0106] 10…First film, 11…First base material, 12…Metal vapor deposition layer, 13…Metal vapor deposition film, 15…Resin coat layer, 20…Second film, 21…Second base material, 22…Printing layer, 30…Third film, 100, 200…Laminate, 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, wherein the first adhesive layer is formed using a urethane-based solventless adhesive, the first film includes a metal vapor deposition layer and a resin coat layer that covers the metal vapor deposition layer and forms a contact surface with the first adhesive layer, and the resin coat layer includes a urethane-based resin and a cellulose ester-based resin.

2. The laminate according to claim 1, wherein the resin coat layer contains a filler.

3. The laminate according to claim 1, wherein the metal vapor deposition layer is an aluminum vapor deposition layer.

4. The laminate according to claim 1, wherein the base material of the first film is a polypropylene film or a polyethylene terephthalate film.

5. The laminate according to claim 1, wherein the second film includes a printing layer.

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

7. The laminate according to claim 1, including a sealant layer.

8. A packaging material comprising the laminate according to any one of claims 1 to 7.

9. A packaging bag formed by bag-making the packaging material according to claim 8.

10. A method for manufacturing a laminate including a metal vapor deposition layer using a solventless adhesive, the method comprising: a preparation step of covering the metal vapor deposition layer of a metal vapor deposition film with a resin coat layer including a urethane-based resin and a cellulose ester-based resin to obtain a first film; and a lamination step of bonding the first film and a second film using a urethane-based solventless adhesive, wherein in the lamination step, the first film and the second film are laminated such that the resin coat layer and a layer composed of the urethane-based solventless adhesive are in contact with each other.

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